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a N H THE \ageda hie

QUARTERLY JOURNAL

OF THE

GEOLOGICAL SOCIETY OF LONDON.

EDITED BY

THE ASSISTANT-SECRETARY OF THE GEOLOGICAL SOCIETY.

Quod si cui mortalium cordi et cure sit non tantum inventis herere, atque iis uti, sed ad ulteriora
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 Organum, Prefatio.

1897.
UGH11930
SATO WAL muses
LONDON: oma

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.

MDCCCXCYVII.

List
OF THE

OFFICERS

OF THE

GEOLOGICAL SOCIETY OF LONDON.

ARRAALBRARAIIII ‘

Elected February 19th, 1897.

yee vy.

Present,
Henry Hicks, M.D., F.R.S.
Wice-Prestvents,
Prof. T. G. Bonney, D.Sc., LL.D., F.R.S. | J. J. H. Teall, Esq., M.A., F.R.S.
Lieut.-General C. A. McMahon. Henry Woodward, LL.D., F.R.S.
Secretaries.
R. 8. Herries, Hsq., M.A. | J. E. Marr, Hsq., M.A., F.R.S.
Foreign Secretary.
Sir John Evans, K.C.B., D.C.L., F.R.S., F.L.8.
Creasurer,
W. T. Blanford, LL.D., F.R.S.
COUNCIL,
H. Bauerman, Esq. R. Lydekker, Esq., B.A., F.R.S.
W. T. Blanford, LL.D., F.R.S. Lieut.-General C. A. McMahon.

Prof. T. G. Bonney, D.Sc., LL.D., F.R.S. | J. E. Marr, Esq., M.A., F.R.S.
Prof. W. Boyd Dawkins, M.A., F.R.S. Prof. H. A. Miers, M.A., F.R.S.
Sir John Evans, K.C.B., D.C.L., F.R.S., | H. W. Monckton, Hsq., F.L.S.

FE.LS. E. T. Newton, Esq., F.R.S.
F. W. Harmer, Esq. A. Strahan, Hsq., M.A.
R. 8S. Herries, Esq., M.A. J.J. H. Teall, Hsq., M.A.,"F'.B.S.
Henry Hicks, M.D., F.R.S. W. W. Watts, Hsq., M.A.
Rey. Edwin Hill, M.A. W. Whitaker, Esq., B.A., F.B.S.
Prof. E. Hull, M.A., LL.D., F.R.S. Rev. H. H. Winwood, M.A.

Prof. J. W. Judd, O.B., LL.D., F.R.S. Henry Woodward, LL.D., F.R.S.

Q

Assistant-Secretarp, Clerk, Librarian, anv Curator.
L. L. Belinfante, M.Se.

Assistants in Office, Library, anv {Hluseum.
W. Rupert Jones. | Clyde H. Black.

TABLE OF CONTENTS.

ANDREWS, CHartes W., Esq. On the Structure of the Skull of a
etirasatite (Cela te ee) searches one 0 os ope Ola oo Seine ere

Aston, Miss E. Water Analyses from Wells in the Nubian Desert,
SOME CASL OLA OLOSIO' § «3H. Nojvearese . cboketrvteneaar ese: © sieve aielens iter

BuiakE, Rev. J. F. On some Superficial Deposits in Cutch ......

Bonney, Prof. T. G. Additional Note on the Sections near the
Summit of the Furka Pass (Switzerland) ..................

Bucxmay, 8.S., Esq. Deposits of the Bajocian Age in the Northern
Cotteswolds: the Cleeve Hill Plateau. (Plate XLVI) ......

CaLtaway, Dr. CHartEs. On the Origin of some of the Gneisses
OH RIN eS a OR Oem Ae uoinee, 51.0 SOS Or iben Joins oo cr?

Davison, Dr. CHartEs. On the Distribution in Space of the
Accessory Shocks of the Great Japanese Harthquake of 1891 ..

——. On the Pembroke Earthquakes of August 1892, and
iovenmber 1899.,4 (Cela te Oe ye cy Lydd etch orate: ayetere woxsps.onekeveto

Draper, Davip, Esq. Notes on the Occurrence of Sigillaria,
Glossopteris, and other Plant-remains in the Triassic Rocks of
SMa MMETIP NMAC cle Wc 5 oatse) adn eno Siasferss soba of anor ss ars Se tee ene Oe

Etes, Miss G. L. The Subgenera Petalograptus and Cephalo-
prays. (SELENE GUH ea.G AE) eae eee ccine coo oan oom oot

GarRDINER, C.1., Esq., and 8. H. Reynoxrps, Hsq. An Account
of the Portraine Inlier, Co. Dublin. (Plates XLIT & XLIIT.)..

Page

Wag

O74

223

16

607

349

157

310

186

520

Gostine, A., Esq. Izaico and other Volcanoes in Central America, 221

a2

1V - TABLE OF CONTENTS.

Page
GREGORY, Dr. J. W. On the Affinities of the Echinothuride ; and
on Pedinothuria and Helikodiadema, two new Genera of
Helimoidea. (Plate Vil.) epee te eee ee ee 112

. On Echinocystis and Paleodiscus, two Silurian Genera of
Bchinoidea, (Plate VIL), eco eae ees on eee 1238

GREsLEY, W.S., Esq. Coal: a New Explanation of its Formation;
or the Phenomena of a New Fossil Plant considered with
reference to the Origin, Composition, and Formation of Coal-
beds. (Abstract ii isk in hast oe. ee 245

Hicks, Dr. Henry. On the Morte Slates and Associated Beds in
North Devon and West Somerset.—Part II. (Plates XXXI-
DON) a eR. Cnet iN 438

Hottanp, Tuomas H. On Augite-Diorites with Micropegmatite
mSouthern tndia, (Plate XNITK.).., co. sccc eee ee ee 405

Hott, Prof. Epwarp. Another Possible Cause of the Glacial
ORM, UCAS RACE fiero ane ee nek he ete 2 ee 107

Hung, Dr. W. Fraser. The Cretaceous Strata of County Antrim.
(ines OVI UV.) eee eae nn on nae ioe eer 540

Kaysrr, Prof. E. Note on Volcanic Bombs in the Schalsteins of
ENP er ite i ae aca GS pits at nm Gon Rene Ie a eg 109

Lyons, Capt. H. G. On a Portion of the Nubian Desert South-east
of Korosko: Field Geology. (Plate XXVI.) .........-.50¢ 360

McManovn, Lieut.-Gen. C. A., and McManon, Capt. A. H. Notes
on some Volcanic and other Rocks, which occur near the
Baluchistan-Afehan frontier, between Chaman and Persia.
(tates ey TION.) ese we Wa «bh ae be be we gs Vee 289

Nerwron, E. T., Esq., and J. J. H. Teatz, Esq. Notes on a Col-
lection of Rocks and Fossils from Franz Josef Land, made
by the Jackson-Harmsworth Expedition during 1894-1896.
Rabe, ONE ET yoo icles bua tee Se o's i AT7

PARKINSON, JoHN, Esq. Some Igneous Rocks in North Pembroke-
Blanrercn (ta he! ORY BAY i bee ciseta tk ele ln fy ele lo. u cokes lett eee A65

Ratstn, Miss C. A. On the Nature and Origin of the Rauenthal
Serpentine. (Plates XVI & XVII.) ............ She» Ae 246

Petrology of a Portion of the Nubian Desert South-east of
TOROS Is ca tele asian lets oie pata pels c's ca ince oltre sta ole ee 364

ReEave, T. MetLARD, Esq. The Glacio-Marine Drift of the Vale

of Clwyd. (Plate XXV.)......... pre he) 341

TABLE OF CONTENTS. Af

Page
Reep, F. R. Cowrsr, Esq. The Fauna of the Keisley Limestone.—
erat pel, © EMME OV EL) cce4 8 disc tale e ma ekos daalaiaae «cs he males « 67

The Red Rocks near Bunmahon on the Coast of Co.
W aterford 269

2.8), '6 FF 0 8 6: 6 OC vd 0,0) @..@ O Bs) wa) Bie (e) 9) ec wt) RO) ae) @ 19) B®) (0: 0, oe) a8 6) 68

——. On the Fossils from the Portraine Inlier, Co. Dublin .... 535

REID, CLEMENT, Esq. Pleistocene Plants from Casewick, Shackle-
swell sand: Gurdiyst cise sa vseeee nate ae hore eee mete ain ers 465

Reynowtps, 8. H., Esq., and C. I. Garpiner, Esq. An Account 1
of the Portraine Inher, Co. Dublin. (Plates XLII & XLIII.).. 520

Ricwarps, EK. Percy, Esq. The Gravels and Associated Deposits
at N ewbury. (ERIE ee MONG) Vly alee aah Seeks! sings ahaa oreo) op gos 420

SEWARD, A. C., Esq. On Cycadeoidea gigantea, a New oS aes
Stem from the Purbeck Beds of Portland. (Plates I-V.) . 22

——. On the Association of ee and Gilossopteris in South
Africa. (Plates XXI-XXIV.)

DRE ee Cel ee ny ee eee 15
STEBBING, W. P. D., Esq. On Two Boulders of Granite frem the
Middle Chalk of Betchworth, Surrey. (Plate XV.).......... 213
STRAHAN, AUBREY, Hsq. On Glacial Phenomena of Paleozoic
Age in the Varanger Fiord. (Plates VIII-X.)..,........... 137
——. The Raised Beaches and Glacial Deposits of the Varanger
BRIOEHE Nitahs coat) is Neale a i erg ee aioi Reape cy paths « Hane ere LAS
Tarr, Prof. Rautew 8. Changes of Level in the Bermuda Islands.
CARBMCE Ee ne ain wale taht Se Naan eee tues sie > ¢ialss ©). Sah oes 222
Treat, J. J. H., Esq., and E. T. Newton, Esq. Notes on a
Collection of Rocks and Fossils from Franz Josef Land, made
by the Jackson-Harmsworth Expedition during 1894-1896,
GEA rea MOON HL SAD MI ern ts See feo e acl’ sco ee data oak neee's 477
Water, T. L., Esq. Geological and Femoermpieal Studies of
the Sudbury Nickel District CO crreabea ake ole oi bec ashes © bs ot arora we 40
Wuipborne, Rev. G. F. Description of Fossils from the Morte
Slates, and Associated Beds, in North Devon and West Somerset.
eles 2S 2 @.9.8 De en ee 445

Woops, Henry, Esq. The Mollusca of the Chalk Rock.—Part II.
evens BOO. @.G 10 1 Ee Rene nee ee a an 377

vi . TABLE OF CONTENTS.

PROCEEDINGS.

Page
Proceedings of the Meetings .............. Gee RO 1, xcill
PNSHMMTIAL ARE POEG - sishc te a cao oe St oieee eee Peete nie arenes aia e Glia wa vill
Histor onors:te the abrany | eee os ees aoe * meee xii
histiof Horeion (Members ../ «ci. es 0 ce echoes = oie aeons meee eae XXlli
iast:of Moreign Correspondents 2. 0.21. neas, sec pmeee eh ee XX1V
Last of Wollastan Medallists ; 2. shel. es uals 6 0's sis a ieee ee XXV
Inet of Murchison Medallists... 00.00.25. :.0.204 0. eee XXVil
Last’ at Muyell Medallistse Miia ala euias «cee 6 oo Reh doa ee XXVIll
Mstiot Bissby Medalists. s\.ice atte sic So's cles Gis's.38 > wa ee XX1X
Applications of the Barlow-Jameson Fund ..............+.004: XxXix
Prine EG MORE Witness io atlas tastes ai icis vis cols Sos aces Oe 2.00 4
Auwato of the Medals, BbC./s.....«cicjsiaiei-teerd ea wats Cr. thes eee XXXVli
ALMITEVCRSeiy ON CO EES fe ul chee pci y sip oe ud or hee chess hie xlix
Sree General MGenmigs: ai. sje «ee pints wien layaiis ts bees iv, Vil

BuakE#, Rey. J. F. The Laccolites of Cutch and their Relations
to the other Igneous Masses of the District. (Title only.).... xevii

Hicks, Dr. Henry. Announcement of the decease of Prof. A. H.
Green and of the Prestwich Bequest’ .....,.1...sece+..0) i
. On Mr. C. E. Beecher’s models of Triarthrus ........ XCVi

Lostey, J. Logan. On the Depth of the Source of Lava. (Title
CET RAR STON atv sb ahi cB ele Rare Mm a De nS SRD ees XCiV

Wootacort, D. An Explanation of the Claxheugh Section, Co.
Durham... (T2tle only.) oo... os Spain acs rae tae bela Hi Be XCIX

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.
PLANTE.
Anomozamites? Pl. xli. fig. 8 ... ,)
eo cf. whitbiense. “PL. xli.| |? Oolitic ......... | Franz WOcee
Baiera? Pl. xxxviii. fig. 10 eRe bate dees
’ cad apes Jurassic ......

' ? Permo- Casey’s
Cardiocarpus sp. Text-fig. 1d ... RAR eos Township
Conites sp. Pl. xxii. fig. 2 ......... { : Foren ep Vereeniging
Cycadeoidea gigantea. Pls. i-v. &

ROME OS. OFS Bloc ar eden sccm Gian Purbeck Beds...| Portland.......
Fieldenia [Torellia]. Pl. xxxviii.) { ? Upper ( Franz Josef

Pee WD ss ps dywmidiesnGe aqumecomae spose Jurassic ...... Wire scgien
Gangamopteris cyclopteroides.| f ? Permo-

Text-fig. 1c & pl. xxii. fig. 1 ... Carboniferous} Transvaal ....
Ginkgo polaris ? Pl. xxxviii. figs. 1-| { ? Upper )

PP sine oe te nasece deb saan anticiond { Jurassic ...... lp Tee

reniformis ? Pl. xii. fig. 10. i sd arti

siberica? Pl. xxxviii. figs, 4 & [ ? Upper |
PPE doo -aieris/s est eg=adoweadansnses Jurassic ...... 3

NOR Meee arcu s 22 dancnen ctleatignatapterae

Boschmans

var. indica. ~-Pl. xxi. Carboniferous

GRE ea sep we 5 4a sale cso
Neeggerathiopsis Hislopi. Pl. xxi.
fig. 6

—_———

Boschmans
Pie Oh “cceecepe ema seacs cise eddies cates
Phyllotheca [Equisetites] ¢f. co-

+48 Franz Josef
lumnaris. PI. xli. figs. 1-3...... 1 oat sess ene

Hand) -.3.. 5:

Fontein ...

Pontein ..,.:.

fie. 4.4...... ee Oh See Pots f Permo- 1 Te een

and: = cove.

Page

Vili

FOSSILS DESCRIBED AND FIGURED.

Name of Species. Formation. Page
PLANT& (continued).
Phyllotheca sp. Pl. xxiv. fig. 1... { ? Fermo- Maggies Mine...| 324
y SPO ea Oc tae ais Carboniferous g8 sia
Pimites:: Pl. xii. fig, VO... 5. Fee-.: 7 ( 506
Pinus spp. Pl. xxxvili. figs. 6-8 . | iiianee 494
Podozamites lanceolatus? PI. sed | Franz Josef
=f Jurassic ...... \ ~
ACV HPD wakincebockeewslyoves | alee el | | 495
Rhiptozamites ? cf. Geepperti. | |
di pod bah fed oa Fl Pen caes) <i e BOO. Aes J | 504
Sigillaria Brardi. Text-figs. 2a—p) |
& 3, pl. xxi. fig. 3. & pl. xxiii. fig. 2) | 326
p unis sp. Text-fig. 2f, pl. xxii. | ? Permo- Transea
fig. 4a & pl. xxiv. fig. 3 ......... | Carboniferous 330
Sphenopteris sp. Text-fig.la@ ... ) { Casey's 339
Thyrsopteris? Pl. xxxviii. figs. 13 &| ) ? Upper
ACY | FARES ODAC SS Oe HNO ANE Eee a Jurassic ...... Franz i osef 495
Zamiopteris? ¢f glossopteroides; . . ## Jf Land wicca .
1) ora Wa tf Wes Or ae ae ae TOOMEIC ct. neat 504
Incerte sedis. Pl. xxi. fig. 5, | { ? Permo- inancraal oe
pl. xxii. fig. 40, & pl. xxiv. fig. 2.) 1 Carboniferous } se 333
GRAPTOLITOIDEA.
Cephalograptus cometa. Pl. xiii. ) (
freee OMe Fa Gains atlas wal | 204
petalum. PI. xiii. figs. 6-9 || | ye ae 9206
Petalograptus folium. Pl. xiii. r Ordovician aisseiea| | eeOIUCHEe eee
Ge ets anit) teeta veve! cegies'es | | 188
—— minor. Pl. xiv. figs. 17-21 ay \ 201
——- ovatus. Pl. xiv. figs. 15 &16.| Tarannon Shales| ? Conway......... 199
Pl. xiv. figs. 1-4 |} (193
— —— var. latus. Pl. xiv.
BRS AME) SNe ein soe wninalevcteebianie victha aces | 195
—— ovato-elongatus.) } Ordovician ...... Britain | ood
Pl. xiv. figs. METAS hee ee 197
woe var. tenuis. Pl. xiv. |
EI AO OOP LO) oe eRe Wlecinan steals wnals ) \ 196
ACTINOZOA.
‘ Us
Bridopbyllum sp. sn. .02| f Morte Slates ...| Treborough....u] {$28
; ; ? Upper Franz Josef ;
oar a pice SG os { Jurassic ...... Ue Dand (2 tea 498
reais ee, oe ok i se } Morte Slates ...} Treborough...... 456

FOSSILS DESCRIBED AND FIGURED 1X

Name of Species. | Formation. | Locality. Page
EcHINODERMATA.
oer Keisley Lime- .

NUM OU CAR acces a cene canes vaceeoe scee> { Wi RENEE UE } Keisley mak cea se 83

SaRMEANE Reso os ashok adc <ciebtaseaone Morte Slates ...| West Somerset.| 456

Kchinocystis. Text-figs. 1-3 ...... ee ree a } Leintwardine ... {159°

Helikodiadema, Text-figs. 7-10...) Chalk ............ Hugland .....-..- 121

ae Text-figs. 4 & 5..... : | ane \ Leintwardine ... fast

Been GONEENES, AE Weisser Jura ...| Germany......... 119

Spheronites pyriformis............... Rosey ae \ Keisloyiynatce. +4 82

TRILOBITA.

Dalmanites [Cryphzus] laciniatus ?| \ ( (
var. occidentalis. Pl. xxxiii.| | | |
HIS A. 25 wot oee.Sndnecosesee ‘ Morte Slates ...|{ Oakhampton ...|{ 445

So. beat fies. 18) 7. .15) | | 447

Homalonotus sp. Pl. xxxi. fig. 4 | ) | Treborough...... \ 447

Trinucleus seticornis, var. port- phe
TENE LEM SUSY ada a Dt dee nate senia gasses } UO aE PQECEBENOS signs? 288

BRACHIOPODA.

Atrypa expansa vars. a, B, &y .. ; 71

Atrypina similis. Pl. vi. figs. 2 tee fi dala Keisley .........
AS Ge ee StOMe sees. j 72

Chonetes plebeia, PI. xxxiii. figs. 1) )

BUD ee cn bien ancamawaaaeswomeee \M faSlaites Treb i 454

sarcinulata? Pl. xxxiii. figs.| f~ OT MANES --- Fae rae eset
SA Oe a Oo pane Mey Bn 455

Dayia pentagonalis. PI. vi. figs. 5,| ) » (
ENOL ORE SCRTIC REC eee SERRE Pa | 74

Hyattella Portlockiana ............... | | 75

Oholella. 672 Mitens’ | .2....ceneseanee: | Keisley Lime- 67

Orbiculoidea sp........ scinauivisaiecinpniade f Shoie?! £25 .3..- t Jen ; 67

Orthis calligramma var. ............ | 68

| Hebertella? | keisleyensis. Pl. | |
wane La Or NO yt sec cscs ) ) 69

Rhynchonellahercynica? Pl. xxxiy. ) 2
A OAD BED ovo k owen csecse 451

——nympha? Pl. xxxiv. figs. 6 Morte Slates . 5 Leen “oe
OTe iio sho Maacti jesse wen nei J 451

Rhynchotrema cf. dentatum......... { epecel aa } Keisley) if...0c5. 73

Spirifera spp. Pl. xxxi. fig. 10 & ) (

{le RMI VE OSI: Ge ay cu teseeads vee tee West Somerset .| 450

Streptorhynchus? persarmentosus. |
PEt yligs, Aedo' Oj .5. esate ses | Treborough...... 454

Stropheodonta teniolata. Pl.xxxiv. r Morte Slates ...

AOR Oe Ge toes Pavia, once cohen say Oakhampton ...| 452

Strophomena explanata? Pl. xxxi.
figs. 11-13 & pl. xxii. figs. 1-3| ) | Treborough...... 452

re afinis. PI. vi. figs. 4& ores Lime- | Keisley Ree 73

FOSSILS DESCRIBED AND FIGURED.

Name of Species. | Formation. Locality. Page
LAMELLIBRANCHIATA.
Anodontopsis sp. Pl. vi. figs. 9 & | Keisley Lime- | | TEE con. 81
OD vin cscs as ons Sacelee cn sh emoeaneaanar stone. |
Area cf. Galliennei. Pl. xxvii.) \ \ (

fig. SOSA eens Pao ska aseomads | | 378
—— [Barbatia] cf. Geinitzi. PI. |

RV HGS. DiC. Sane cw nce vane > Ouckhamsley ...|{ 378

Bp) PL exx vit mip es + Chalk Rock...... | | 379
Arctica ? equisulcata. Pl. xxviii. figs. Sai
EO ache Sete Pee nea ; le
me PERS bo SET a as | Hingland %..-.-c, 390

pl. xxviii. fig. 1 eee
Avicula cf. i ivalvis, Pl. xl. a ese Josef

“ule of inmauivlis” "P| pppoe Fura {ame Zot | a
Aviculopecten mundus. Pl. xxxiii. ;

fics 14, 14 eee ee } Morte Slates ...| Oakhampton ...| 449
Cardita cancellata. Pl. xxviii. figs.| \ | England .......-. 390
Cardium cf. cenomanense. PI. | P| (

KV. fies. 25 da eeeeee ss. -+ rece 389

turontense. Pl. xxvii. figs. \ Chalk Rack ee

(a) pb A See) DIT Gem yaaa iy
Corbis? Morison. Pl. xxviii. figs. | fp Guekhomely 4

13614 |... ee | 392
Cuspidaria caudata. Pl. xxviii, |

fies 19 & 20 2k } (393
Cypricardinia? sp, Pl. xxxi. fig. 5. 447

aire -9 ;
ae bp he | ilone ielaies rage: 448
Grammysia? sp. Pl. xxxi. figs. 7-9) 448
Inoceramus striatus. Pl. xxvii. | f
Cy eae soteseceteeteatensecenees Ragland ae 381
sp. Pl. xxvii. figs. 14-17......| } Chalk Rock...... 381
Lima | Plagiostoma] Hoperi......... (383
Limopsis sp. Pl. xxvii. figs. 7 & 8. Cuckhamsley ...| 379
eet Poo eae | Morte Slates ....| Oakhampton ...| 449
Martesia? rotunda. Pl. xxviii.| \

A611 ie on: | } Cuckhamsley “| 993
Modiola Cott. Pl. xxvii. figs. 9-12} | England .........| 380
Nucula sp. Pl. xxvii, figs. 1 &2...| [CMM Rock-----| Cuckhamsley ...| 378
oe } Winchester...) 887
Pterinza subfalcata var. ..........4. Ne elie } Keeisleys...c0t.vas 81
Spondylus spinosus .................. 885
Trapezium trapezoidale. Pl. xxviii.| | England .........

figs. 9 & 10.......0010-seeererrenneee S Chalk Rock...... ) 391

Moe ee ee } Cuckbamsley ...] 392

FOSSILS DESCRIBED AND FIGURED. x1

Name of Species. Formation. Locality. Page
GASTEROPODA.
Eunema carinatum var. ............ \ (is
Loxonema striatissimum. Pl. vi.
fig. s Be eset ae See Ge actaetere nae pee | 78
Murchisonia sp. nov.? Pi. vi. eisley Lime- :
HEROIC Gaeta udaeunsiteces ote a | Keisley he eee 4 80
Platyceras ¢f. cornutum ............ ris,
verisimile. P1. vi. figs. 7, 7 a,
GTO esses came cen ceitee Oder vines y ) Vat?
CEPHALOPODA.
Ammonites [Macrocephalites] | ? Upper \ ff
Ishme var. arcticus. Pl. xl. .. Jurassic ...... | 500
— macrocephalus. Pl. | |
MORES es | wae at wean eaiocn ates | 497
[Cadoceras] modiolaris. PI.
pomxacesterg 1.0! 5225. .vdhantoesdeines : | 497
miehohani? Bil xenie | Callovian..-..... f ead i Josef | 4
PB ey eel oie. vac wedaeeanadasades: i | steasainal 4 496
Belemnites Panderi. Pl. xxxix.| |
HBL HNS: os... doce e sana haan J | 498
; ? Upper ; OOL
Tif RENE ALE ES ER os nome Jurassic... ; (502
Orthoceras cf. scabridum............ / beets ee \ Keisleyy *.25.65.<. 77
Sa Pee j

PLESIOSAURIA.

Pliosaurus ferox. Text-figs. 1 & 2

(Sh Oj eal abene enc loan Oncanenee enerace

|} Ostora Clay _., Peterborough . pie

Dent
; : appa"
‘
-
-
: ‘
’
. .
, ¥
t -
o Z
~ n
, \
- i
Fy
= i
'
.
Wy 7 -
’ a
> F
!
' S cea
i Y
,
A i ‘ a
‘6 ’

EXPLANATION OF THE PLATES.

PLATE

Tv { CycADEorpEA, MacrozAMiA, AND BENNETTITES, etc., to illus-
“~"* | trate Mr. A. C. Seward’s paper on Cycadeoidea gigantea... 22

Pace

to illustrate Mr. F. R. oo Reed’s paper on those

BRACHIOPODA AND MouuvuscA FROM THE KeEIstEY LIMESTONE,
VI
HOSSUL GE ce eee Ee Ie a ei ene eR Rg 67

VII PrpinotHurRIA, HcHINOCYsTIS, AND PaLzxoptscus, to illustrate
Dr. J. W. Gregory’s papers on those fossils ............ 112, 123

ConTEMPORANEOUS BovuiLpER CLAY BETWEEN QUARTZ-GRITS
(GaisA Brps); QUARTZ-GRITS BEDDED ON AND AGAINST
ConTEMPORANEOUS BouLDER CLAY ; and ConTEMPORANEOUS
VITI-X.{ Bovunper Cay, RESTING ON A GLACIATED SURFACE OF
QUARTZ-GRIT, AND OVERLAIN BY QvUARTzZ-GRIT, to illustrate
Mr. Aubrey Strahan’s paper on Glacial Phenomena of

Palzozoic Age in the Varanger Fiord ..............-.ec0ec00s 137

Mar or tHe Premproke HARTHQUAKES oF August 1892
AND NovemsBer 1893, to illustrate Dr. Charles Davison’s
paper on those earthquakes Bajah Peet ati deece As 8) enameled 157

SKULL oF Puiosaurus FEROX, to illustrate Mr. Charles W.

XU. | ““Andrews's paper on the Cranial Structure of that reptile... 177

Hilles’s paper on those subgenera. ........0...essncteeseonecsenes 186

Tue BrtcuwortH Bovupers, to illustrate Mr. W. P. D.
Stebbing’s paper on two Boulders of Granite from the
Middle Chalk of the above-named locality .................. 213

XV.

SKETCH-MAP, SHOWING THE APPROXIMATE PosITION AND CHA-
RACTER OF THE RAUENTHAL SERPENTINE; and MicroscoPE
SECTIONS OF THAT AND THE Bonnomae SERPENTINE, to
illustrate Miss Catherine A. Raisin’s paper on the first-

pears ae Ie a etoilata del ow Samia de sowanctesiamitawied heen aie 246

SKETCH-MAP OF THE BALUcHIsTAN-AFGHAN FRONTIER; and

XVIII- Microscore-sections of Rocks from that district, to illus-

XX. trate Lieut.-Gen. OC. A. McMahon and Capt. yap a
McMahon's paper on those rocks ...........cscscsseescssesees 289

XVI &

\

ae oh nee AND CEPHALOGRAPTUS, to illustrate Miss G. L.
(
|

XVII. |

mentioned rock

X1V EXPLANATION OF THE PLATES.

_ PLATE PaGE
[ GLOSSOPTERIS, N@&GGERATHIOPSIS, GANGAMOPTERIS, ConITES,
XXI-— SrigILLARIA, Puyniotueca, ete., to illustrate Mr. A. C.
any Seward’s paper on the Association of Sigillaria and
Gilossopteris in South sAiricaget eres c.cctece te eeeec tes ceeca seen 315

GroLtogicaL Map oF PART OF THE VALE OF Cuiwyp, to illus-
XXV. trate Mr. T. Mellard Reade’s paper on the Glacio-Marine
Dritt ofthat merrhbourhaud Gietes-ccssecaes eens. cae eee 341

GEOLOGICAL Mar or A PorTIon oF THE NuUBIAN DESERT SOUTH-
XXVI. EAST OF Korosko, to illustrate Capt. H. G. Lyons’s paper

ONM a iGUSEITCt jdein «a elas desea ute done. Cae den Sukh Behe Pee een eee 360
XXVII & { Cuatx Rock Mouuvsea, to illustrate Mr. Henry Woods's
AXVIII. | paper on those fossils ........0.cesseseeeseeeees sre sktsseeaeeeee 317

XXIX. { MicroPEGMATITIC AUGITE-DIORITES FROM SouTHERN InpIA,
to illustrate Mr. T. H. Holland’s paper on those rocks ... 405

Map or Newsury, anv Sections, to illustrate Mr. E. Percy
Richards’s paper on the Gravels and Associated Deposits

GNeT EMO CA MUR AS: ON diet) MEM Cote Aico bat Michiels sh. oS 420
TREBOROUGH AND OAKHAMPTON Fossits, and GEroLoGIcAL
XXXT-— Mar or A Portion or West Somerset, to illustrate
XXXV. Dr. Henry Hicks’s paper on the Morte Slates, and Asso-

ciated Beds, in North Devon and West Scmerset............ 438

Microscorr-sections oF Ieneous Rocks rrom Nortu Pem-
BROKESHIRE, to illustrate Mr. John Parkinson’s paper on
THIGHS (TOGKS W. .aSeceeeen Reena eee te es Mean ee ERE ee 465

| Some -SECTIONS OF Basauts, ETc.; Fossiz Puants;
\

XXXVI.

XXXVII- AND AMMONITES, BELEMNITES, ETC. FROM ‘Riana JosEFr LAND,
XLI. to illustrate Messrs. E. T. Newton and J. J. H. Teall’s
paper on’ that: repo! Jed. ce sei sideck oe cent tauren tomeaeaeee AUT
XLII & SECTION ALONG THE Coast and GEOLOGICAL Map OF THE
XLII. Portraine Iyutur, to illustrate Messrs. C. I. Gardiner and
8. H. Reynolds's paper on that miller. .....2.......:0csennes sen. 520

Upper Cretaceous PEBBLE-CONGLOMERATE AT THE BASE OF
THE CHaLK, Murtoucu Bay; and Comparative SERIES OF
Divis1onAL SEcTIONS IN THE COreETACEoUS STRATA OF
County Antrim, to illustrate Dr. W. F. Hume’s paper
On Those Gbreta ics cents keto s chee atone eee onan eee See 540

XLIV &
XLY.

Map or tHE Bagoctan Denupation, to illustrate Mr. 8S. 8.
Buckman’s paper on the Bajocian Strata of the Cleeve

XLVI.
TTT PURO hao ae Gat ce eee ss alt ee eedbiscre Suthewes Ace eateries 607

PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES

FIG.
1-8.

bo

He <- Qaeee See ee oe

BESIDES THOSE IN THE PLATES.

PAGE
Maps representing the distribution of earthquake-shocks in
DEORE Sahota eee eed cdsactcasec hate aaécercisawdocsacatcs<ueedncace’ 4-7

Diagrams of the western side of the summit of the Furka Pass 17, 18

Diagram of quarry-section at Portland ...............cceseeeeeeee eee 22
Transverse section of the stem of Cycadeoidea gigantea ......... 23
Apical bud of Cycadeoiden giganted ..............scceceeeesseseeeess 24
Apical bud of Encephalartos Altensteint? ...... 2.010. cescenceeeeeees 32
Geological Sketch-map of the Sudbury District (Canada) ...... 64
Portion of quarry-face in schalstein, at Rumpelsberg, near

O) ees Lie fe Besse Am daar atc Aneel 110
Ambulacral plates of Phormosoma Uranus .......20..s-eceeeeeeees 115
Ambulaerall plates ob Pelamechiius 2... .scc.0cscoi0.vsentscosscssaceae 116
Ambulacral plates of Phormosoma bursariwm .........1.000eeee0e 116
Ambulacral plates of Phormosoma luculentum ...........000000ees 117
Auifellaeral, plates:6f Patina. ....c..>ssiptheat aesh.bes 2. eo-- 118
Ambulacral and genital plates of Helikodiadema ..............00+5 121
Amibulactall plates Of LCHNOcystts -vuscana: sjsaeaiccads.-deavessee-a3 125
Pyramid from the masticatory apparatus of Echinocystis ...... 125
Ambulaeral plates of Pal@odiscus .......cecssccsssevescvessceeceases 129
Pair of half-pyramids of Pal@odiscus ..........cs.c0ceesseeeseesseseee 130
Naps of Ee. Varancer Wierd. 5252230005. diac2eq-0secseensoan sae oseeebSe 138

Map of the Epicentral District of the Pembroke Earthquakes.. 158
Posterior portion of the palate of Pliosawrus ferox .............+. 179

Lateral view of the cranium of Pliosaurus ferox

@eeasetssesesesses

xvi

F

1

PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES.

IG. PAGE
Diagram of early stages in the development of Petalograptus
POUVUHU Pe gs he eS EOI ea Ne sn 6b sled on ROO eee 190
9. { Microscopic sections of granite-boulders from the Chalk of
a Bebeh worl | x.2.ha23. dae setae MeaMeM ee nee oor Gus Socns ve cael ee eee 216
Geological’ Map, of ‘a portion of Cute .n7-.scdcocsse sens. mane 224
1, Section ona ‘stream. west of Kotae cet. avy ccc.scdsacenceeescceeeneee 231
2. Boulder-beds in the north of Patcham .................ssceeeceeeees 233
3. Jnfratrappean grits at Bhujia. Hill. .:..0.2.¢.sc.:.s.0oeaeeeeee 235

Olivine-serpentine and ‘amphibolite’ (Rauenthal) in thin
BEC ULOM) Mieke caasinc.-\co ta suntawauereceuaiieastacdsssobes theese aaa 249

1. Section in the cliff at the E. end of Ballydouane West Bay ... 273

2. Ground-plan of the foreshore, W. side of Ballydouane Bay ... 274
3. Section in the cliff at the N.E. corner of Ballydouane Bay...... 275

ue aromas sections of cliffs on the N, and H. sides of Bally-

GOUBTIOMBHY acct. tkctdeceeaeets aseees eaceeeetse oncsaceet cee 277
6. Section of the W. face of Kennedy’s Island, Bunmahon Head . 279

7 Pees of the foreshore on the E. side of Kennedy’s

Island, Bunmahon Heads. 55, socevcctcsceec- ude dnote se hee eee 280

8. Sketch-map of Kennedy’s Island, Bunmahon Head............... 283
9. Sketch-map of the neighbourhood of Ballydouane ............... 284
10. Diagram-section on the E. side of Ballydouane Bay ............ 285

1 View showing sand-dunes covering the lower slopes of the moun-
tains and gradually overwhelming the higher spurs (Registan) 290

2. The Neza-i-Sultan, a natural pillar of voleanic agglomerate ... 294

1 eee y showing the localities where the fossils were dis-

covered (plant-remains from the Transvaal)................0006 310

2. section ab Vereeniging |. 5: s.sr0.qenerartecen scence henncesanies eee 312

38. Section through a quarry 2 miles E. of Vereeniging ............ 313

1. Sphenopteris, ¢ Sigillaria, Glossopteris, C60. ....2+.0.00+s0es0eserene 324

Foe PSUGUNGNIG IBHOT OL, CLC. 00.2.2 4rkerpersee gant aes feiss sides ateenen 327, 329
Diagram of esker south-east of Diserth Castle .................00+ 345

1. Gneiss of primary injection, Llangaffo ................cesesseeeeees 304

2. Blocks of altered and squeezed diorite in grey gneiss ............ 305

PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES. XVil

FIG. PAGH

¥, Gneiss of secondary injection, Llangaffo ...................sseeeee- 356

Rounded boulders in pothole, reservoir of Wadi Om Risha
Nebel Ratt) badacascs soso ee ee see ee ee oer oe erida stern cieee suse 363

1, { Section in Donnington Glacial (?) Drift near Donnington
SQUARE os cavessasacmcant woeeee eeretene Dokbb chose sound Soe M Oo eer a ace 423

2. Section in the Lambourne railway-cutting..........0....--seseeeeees 424

Section in the Upper River-gravel at Bull’s Lane.................. 425

3
+. Section in a gravel-pit on the Enborne Road, aear Newbury... 426
5

Section at the pumping-station of the Drainage-works............ 428
6. Section 30 yards north of the preceding .................-0sece0e0s 429
7. Section in Northbrook Street, Newbury ............. A LMT eA 431
1. Section from Treborough to Withycombe ...............-.-.-cerasee- 439
2. Section from North Down to Battin’s Farm......................4- 439

Sketch of rock with white fragments due to flow-brecciation ... 472

1. Sketch-map of part of Franz Josef TEE TL oS a a 478
A MAG cor Illa 5 Chyoe) IMC decachounenoononoeonk eegeaanenoscanbeceacr 481
3. General view of the western part of Franz Josef Land... facing 512

aa

Vertical sections, showing the probable stratigraphical succes-
SHoyalabm deeaovy diese es DaNnVGl AGE ane enemanconey eubanunns chenee facing 512

i Overtolded Bala Timestone and Shale i.cses.cs ccsccccaer ccs cee scs 528

Limestone-and-shale bands, beginning to be broken up by pres-
sure, in the bay S. of the northern martello-tower (Portraine) 528

St)

. Thrust-conglomerate at Priest’s Chamber ..................00eeeeeee 532

he

Diagram of the cliff at Priest’s Chamber, looking north-west ... 533
1. Diagram of quarries east of the Rolling Bank ..................... 614

» { Diagram-section from Hewlett’s Hill to beyond the Rolling
2.4 MS ATIGM ances este ene ateecbte ace sa caitin ce lst secre sicciaes wc sac /usinatenats eaaage 616

3. Diagrammatic Sketch of a portion of the Rolling Bank Quarry 619

4 eta of the Bajocian Denudation : from Birdlip to Cleeve

oO U eepretsoOt Gomes de DACOR EN aR MA ADR eee h INAn Sty Cea ee eee 621
Oo; 6, | Diagrams) (denudation and overlap) J2icssts.0ssccecsesssecceeonesoes 624
Meipyotmunen Cleeve Mil Wlateatencisc. acssaveusseescessadessocsertss 628

VOL. LIT. b

} Vol. LIT. FEBRUARY lst, 1897. No. 209. :

. ‘

QUARTERLY JOURNAL

GEOLOGICAL SOCIETY.

EDITED BY

THE ASSISTANT-SECRETARY.

[With Seven Plates, illustrating Papers by Mr. A. C. Seward, ;
Mr. F. R. Cowper Reed, and Dr. J. W. Gregory. |

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ema i io Vee ge ig Fy . q oa:
LIST 328 OF TH eae ee

GEOLOGIOx. — _eTY OF LONDON.

x .
ve eee
Sa ae,

sy Sv

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

Wice-Presivents. 8 ge

Prof. T. G. Bonney, D.Sc., LL.D., F.B.8. | R. Lydekker, Esq., B.A. F.RS.
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F.R.S. Lieut.-General O. A. M¢Mahon. a
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[Business will commence at Eight o’Clock precisely each Evening.} Ried oe

THE

QUARTERLY JOURNAL

OF

THE GEOLOGICAL SOCIETY OF LONDON

Vou. LEE.

1. On the Disrrisurion i Space of the Accessory S#ocxs of the
Great Japanese HartHauakE of 1891. By Cuartes Davison,
Sc.D., F.G.S., King Edward’s High School, Birmingham.
(Read November 4th, 1896.)

I. Intropvuction.

1. The complete history of the Mino-Owari, or great Japanese,
earthquake of 1891 has yet to be written ; but several important
contributions to it have already been made. Prof. Koto, in an
admirable memoir,’ has traced the course of the extraordinary
fault-scarp and discussed the origin of the earthquake; Prof. Omori,”
with equal care and thoroughness, has investigated the unrivalled
record of after-shocks ; and Prof. Milne, in his invaluable catalogues
of Japanese earthquakes,’ has provided the materials for detailed

analyses from many points of view.

My object in this paper is to consider the geographical distribu-
tion of the numerous shocks which preceded and followed the great
earthquake. Prof. Omori has discussed the distribution of the after-
shocks of this and other Japanese earthquakes, chiefly with regard.
to time; but, in an interesting section of his memoir,* he studies
the distribution in space of the after-shocks of the Mino-Owari
earthquake. In order to show the difference between Prof. Omori’s
method of treatment and that adopted in the present paper, I will
first give a brief summary of this part of his work, though it is
difficult to do justice to it without reproducing his maps.

‘<The Cause of the Great Harthquake in Central Japan, 1891, Joura.
Coll. Sci., Imp. Univ., Japan, vol. v. (1893) PP. 295-353 & pls. xxviii —xxxv.

2 *On the After- shocks of Earthquakes,’ Journ. Coll. Sci., Imp. Univ.,
Japan, vol. vii. (1894) pp. 111-200.

ah A Catalogue of 8331 Earthquakes recorded in Japan between 1885 and
1892,’ Seismol. Journ. Japan, vol. iv. (1895) pp. i-xxi, 1-367 (especially
Pp. 134- 243), with maps.

4 Op. supra cit. pp. 141-147.

Oo J.G.8s- No. 209: | B

2 DR. CHARLES DAVISON ON THE [Feb. 1897,

II. Meryons oF REPRESENTING THE DISTRIBUTION OF THE SHOCKS.

2. The great earthquake occurred on October 28th at 6" 38™ a.m.
(mean time of 135° E.), and during the first few days the after-
shocks were so numerous and were separated by intervals of time
so short that the identification of many of those observed at different
places was nearly, if not quite, impossible. But at the meteoro-
logical station of Gifu, and at thirty-two other places in the provinces
of Mino, Owari, and Mikawa, careful records were kept of all the
shocks observed. Plotting on a map the numbers corresponding to
the different stations, Prof. Omori has drawn curves through all
places where equal numbers of shocks were felt during given intervals
of time—namely, 1892, 1893 (omitting the months of January and
September), January 1894, and also during the four years 1887 to
1890. In the first of these maps,’ the marked expansion of the
curves in four directions indicates the existence of as many axial
lines which radiate from a point near Koori, and along which
the seismic activity exceeded that in the adjoining districts. In
the second and third maps, the axial lines proceeding towards Ibi
and the Isé Gulf become insignificant, the other two, extending
towards the E.N.E. and E.S.E., being still distinct; while in the
fourth map no trace of any one of the axial lines exists. One
interesting result which these maps bring out very clearly is that
in the central part of the Neo Valley, which formed the principal
epifocal tract of the great earthquake, the after-shocks were much
less numerous than in the regions to the north and south.

3. The maps (figs. 2-8, pp. 4-7) which illustrate this paper are
founded entirely on Prof. Milne’s catalogues. These give, with com-
paratively few exceptions, the following elements of each earth-
quake :—the time of occurrence, the length, breadth, and extent of
the disturbed area, the course of its boundary, and the approximate
position of its epicentre. For the latter purpose, the whole country
is divided by north-south and east-west lines into rectangles, each 4
degree in length and breadth; and the position of an epicentre is
represented by the number of the rectangle in which it occurs, or, if
under the sea, by its distance from the nearest rectangle on land.

The area included within the maps is bounded by the parallels
34° 40' and 36° 20’ lat. N., and by the meridians 2°10’ and 3° 50’
long. W. of Tokio, so that ten of Prof. Milne’s rectangles adjoin each
side of the map, and the whole area contains one hundred such
rectangles.

In constructing the maps, the number of epicentres lying within
each rectangle has been counted. Sometimes an epicentre is
defined as lying between ‘two consecutive rectangles, and such
cases are divided equally between them.* Curves are then drawn
through the centres -of all rectangles within which the number of
epicentres is the same, or through points which divide the line

1 A reduced copy of this map, showing its essential features, is given in
‘Natural Science,’ vol. vi. (1895) p. 393.

2 It thus happens sometimes that the number of epicentres allotted to a
rectangle is not integral. .

Vol. 53.] GREAT JAPANESE EARTHQUAKE OF 1891. 3°

joining the centres of two rectangles in the proper proportion.
_Taking, for example, the curve marked 5, if the numbers in two
consecutive rectangles are 3 and 7, the curve bisects the line joining
their centres; if the numbers are 1 and 6, the line joining. the
centres is divided into five equal parts, and the curve passes through
the first point of division reckoned from the centre of the rectangle
in which six epicentres are found.

4. In Prof. Omori’s maps, the meaning of the curves is obvious.
At every point of the curve marked 100, for instance, one hundred
shocks were, or would have been, felt during the period embraced by
the map.

The meaning of the curve marked 100 in the accompanying maps
(pp. 5, 6, & 7) 1s as follows :—Let any point in the curve be imagined
as the centre of a rectangle whose sides are directed north-south and
east-west, and are respectively 4 of a degree of latitude and longitude,
then the number of epicentres within this rectangle is at the rate
of 100 for the time considered.

Tf all of the Mino-Owari after-shocks had been exceedingly weak,
so that each was felt at one station only, that place might be
regarded as the centre of the shock, and the two methods would be
the same, except in one slight detail. Some shocks, however, were
strong or violent," and must have been felt at a large number of
stations, and in these cases Prof. Omori’s method of counting the
shock at each station is equivalent to drawing the disturbed area of
that shock. Thus, the difference in principle between the two
methods is nearly the same as that between Mallet’s map of the
world, in which the disturbed areas are coloured, and Milne’s map of
Japan, in which the epicentres only are marked. But, as a matter
of fact, so large a number of the Mino-Owari after-shocks were weak
or feeble that the two series of maps bear a certain resemblance one
to another. ‘The features in which they differ are due mainly,
I believe, to the difference in principle noticed above and to the
shorter intervals of time adopted in this paper.

5. It is important to point out a source of possible error in the
maps, due, however, not to defects in the method so much as to
the approximate character of the available data. In a map of all
Japan which I have prepared, the number of rectangles is so great,
and their size is so small compared with that of the whole country,
that the errors may be neglected except in minute details. But in
the present case the number of rectangles in each map is only
100, and the number to which the epicentres are principally
confined is very much smaller, and therefore the errors may be of
greater consequence. If the epicentres are connected with lines of
fault, it is unlikely that they should be distributed evenly between
the centres of adjacent rectangles. Thus, some error is un-
avoidably introduced into the curves by regarding the epicentres as

' © Of the 3365 after-shocks recorded at Gifu during the first two years,
10 were ‘violent,’ 97 ‘strong,’ 1808 ‘weak,’ and 1041 ‘feeble,’ while in the
ae 409 only sounds were heard without shocks.’ —Omori, op. jam cit.
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all collected at the centre of the rectangle, and the magnitude of
the possible error increases with that of the rectangle. Supposing,
however, the extreme case to occur in which all the epicentres are
situated at one point close to a side of the rectangle, then the
eet deviation of any curve om its correct position would be
equal to 54, of a degree, 2. e. to sy of a side of the complete map.
The probable error is, of course, “ond less than this.

Another source, less of error than of misconception, should also
be mentioned. This is due to the form of the rectangles, a degree
of latitude being always longer than a degree of longitude, except
at the equator. When a number of epicentres lie within a single
isolated rectangle, the resulting curve is a small ellipse whose length
is less than + of a degree, but the direction of the longer axis
has no physical meaning, for it is necessarily parallel to the longer
side of the rectangle.

Again, when a curve is founded on the occurrence of epicentres
in re adjacent rectangles alone, its axis will generally be parallel
to the line joining their centres ; and its direction need not, though
it may, correspond with that of some physical feature, for it is
possible that all the epicentres might be grouped close to the common
side of the two rectangles. It is only when the longer axis of the
curve exceeds in length the sides of several rectangles that we
can make any probable inference as to the connexion between
the distribution of after-shocks and the geological structure of the
district.

6. Turning now to the maps themselves, fig. 1 (p. 4) shows the
outline of the coast within the Mino-Owari district. The dotted lines
represent the boundary of the area over which the principal shock
was felt most severely. The continuous line between them marks
the course of the great fault-scarp, the northern part of which, not
having been actually followed on the ground, is indicated by a
dotted line.! The points A to P denote the centres of the rect-
angles,” within which the majority of the after-shock epicentres
lie; this group of rectangles, as will be seen from the last column
of Table I., contains sometimes all, and never less than ,% of
the total number of epicentres within the district contemplated.
In the succeeding maps, the coast-line and fault-scarp are indicated
by dotted lines, the boundary of the meizoseismal area being omitted
in order to avoid confusion.

The remaining figures are selected from a large number of maps.
Fig. 2 represents the distribution of earthquakes during the pericd
(January Ist, 1890, to October 27th, 1891) immediately preceding
the great earthquake. The others illustrate the distribution of
after-shocks for every two months from November 1891 to October
1892.

* The course of the fault-scarp and the boundary of the meizoseismal area
are reduced from plate xxix. in Prof. Koto’s memoir.

2 They correspond in alphabetical order to the rectangles in Prof. Milne’s
map numbered 1257, 1238, 1352, 1353, 1401, 1402, 1403, 1404, 1457, 1459,
1512, 1515, and 1567.

TasxeE I,

No. of A B C D E F

Hpicentres.

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LES Or Aecadqeets. eee 19
MBB T Secau.tecect twat pect 16
SB Sie Ge cceges cece Top ates 33'5
Mes S\8). qedong aca pae eens 27°5
WOE RS accsse Scie Means ete s 52°5 1
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Oy DR. CHARLES DAVISON ON THE [Feb. 1897,

7. The maps do not, however, give a complete idea of the relative
frequency of earthquakes in different parts of the district, just
as contour-lines drawn at wide intervals do not determine with
certainty the relative heights of the peaks which they enclose. The
preceding Table (p. 9) supplements the maps in this respect. The
letters A to P correspond to the rectangles whose centres are so
denoted in fig. 1(p.4). The figures for each rectangle indicate the
percentage of the whole number of epicentres in the Mino-Owari
district which lie within that rectangle for the month or period
mentioned.

8. It will be noticed in fig. 1 that the meizoseismal area is
forked. The more important branch proceeds towards the south,
while the fault-scarp apparently follows only the shorter branch
to the south-east. From this figure alone it is difficult to avoid
the impression that a considerable displacement, though perhaps not
superficially visible, must have taken place along a fault passing
somewhere near the axis of the southern branch, and this impression
will be strengthened by a glance at the other maps, especially those
in figs. 2to6. Without having any geological evidence of this second
fault, I shall assume throughout the remainder of this paper that it
does exist. Travelling first in a north-westerly direction from the
sea, it probably bends towards the north somewhere near the point
M (fig. 1). But whether it continues to the north joining the
visible fault near the points E and F or turns again to the north-
west about the point K, that is, whether it is a branch-fault or one
of a system of faults, is not clear from the seismic evidence. The
isolated curve in the south-western corner of fig. 2 would seem to
indicate the existence of another fault of such a system, but the
foundation for the inference is not very strong. For the sake
of clearness, however, I will give provisionally the name of the
‘main fault’ to that which is visible on the surface, and of
the ‘secondary fault’ to that whose existence along the southern
branch of the meizoseismal area is inferred from the testimony of
the earthquakes. |

9. The central points C and D (fig. 1), and possibly also E and F,
seem to be connected with the main fault; A and B with the
northern end of the fault-scarp; G and H with its southern end ;
and L and N with a probable continuation of the main fault to the
south-east. The points K, M, and P appear to be related to the
secondary fault.

If we measure the seismic importance of a rectangle during
a given interval by the number of epicentres which lie within it,
the order of importance of the lettered rectangles will be evident
from Table II., the corresponding number of epicentres being
affixed.

Woles3.] GREAT JAPANESE EARTHQUAKE OF 1891. 11

Taste II.

1885-1889. | Jan. 1, 1890—Oct. 27, 1891. | Nov. 1, 1891—Dec. 31, 1892.

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IIT. Tue PREPARATION FOR THE GREAT EARTHQUAKE,

10. According to Prof. Milne, the last severe earthquakes at and
near Gifu took place in 1826, 1827, and 1859.' On May 12th, 1889,
a rather strong earthquake occurred, disturbing an area of about
48,700 square miles, and having its centre within or near the
rectangle F,

The average yearly number of shocks in the district from January 1st,
1885, to October 27th, 1891, is 30. During the five years 1885-1889,
the annual percentage of epicentres falling within the rectangles
A-—P lies between 25:0 and 51:1, the average being 42; in 1890 and
1891 (until October 27th) it rises to a little over 60; while, during
the fourteen months succeeding the great earthquake, the monthly
percentage is never less than 90 and twice is as much as 100.

11. During the first five years, the numbers of epicentres lying
inside the rectangles A—P are respectively 13, 7, 4, 15, and 14;
and the numbers occurring outside them are 16, 12, 12, 18-5, and
13:5. Thus, the number of epicentres lying within the fault-
region increases and decreases with the total number of epicentres in
the Mino-Owari district, showing that the great faults are to a large
extent, though not entirely, responsible for the excess or defect in
the average number of earthquakes.

It is remarkable that, during these five years, only one epicentre
lies within the rectangle K, which is by far the most prominent seat
of after-shocks in November and December 1891, while in the
rectangles M and P there were only three epicentres during the
same period. At this time, therefore, the secondary fault was
almost inactive.

At the northern end of the main fault (rectangles A and B) there
are no epicentres at all during the five years; at the south-eastern
(rectangles G and H) there are four; and 6°5 in the continuation
of the main fault te the south-east (rectangles L and N). The

* Seismol. Journ. Japan, vol. i. (1893) p. 149; Brit. Assoc. Rep. (1892) p. 128.

12 DR. CHARLES DAVISON ON THE [Feb. 1897,

chief seat of earthquakes is in the rectangle D in 1885 and E in
1886, 1888, and 1889; the latter being the second in numerical
importance, and the most persistent, in the district throughout the
eight years considered.

Remembering that the rectangles A—P form only 13 per cent. of
the whole area, it is thus clear that the frequency of earthquakes
was relatively greater within the fault-region,’ and that the seismic
importance of the region increased considerably within about two
years before the great earthquake.

12. The distribution of epicentres during the interval, January
Ist, 1890, to October 27th, 1891, is illustrated in fig. 2(p.4). The
total number is, however, so small comparatively that the essential
features of the distribution are only brought out by adding curves 1
and 2. While the rectangle E is still the chief seat of seismic activity,
it will be seen at a glance how the curves follow the lines of the main
and secondary faults. In this as in other maps, there is a discon-
tinuity in the curves in part of the main fault between the points
Band C. Otherwise, earthquakes seem to have occurred along the
whole fault-system, especially in the secondary fault and the sup-
posed continuation of the main fault towards the south-east. A
noteworthy feature is the uniformity in the distribution of epicentres
throughout the fault-region; the marked concentration of effort
which characterizes the after-shocks is hardly perceptible here.
And this uniformity (as will be seen from Table I., p. 9) is still more
noticeable in the earthquakes of the year 1890 alone.

13. An important point to be decided is how far this remarkable
distribution is a result of the strong earthquake of May 12th, 1889.
The number of shocks in the district in 1890 was 52°5, but in 1889
was only 27:5, of which 13 occurred before May 12th, and 13°5 after.
Indeed, the earthquake of May 12th seems to have been almost
unattended by after-shocks, the number of earthquakes felt in the
district during the last eight months of 1889 being respectively 1, 1,
1, 2,3°5,4,0,and 1. I think, then, that we may conclude that the
distribution of earthquakes in 1890 and 1891 was in very small
measure, if at all, the result of the shock of May 12th, 1889, but is
rather to be regarded as a preparation for the great earthquake, the ~
consequent relief at numerous and widely-distributed points equal-
izing the effective stress along the whole fault-system, and so clearing
the way for one or more almost instantaneous slips throughout its
entire length.

This outlining of the fault-system by the frequency-curves of
1890-91 points, therefore, to the previous existence of the faults,
and implies that the great earthquake was due, not to the rupturing
of strata, but probably to the intense friction called into action by
the sudden displacement.’

l As 53 epicentres were situated during 1885-89 within these 13 rectangles,
and 72 in the remaining 87 rectangles, it follows that the average frequency in
one of the rectangles of the fault-region was five times as great as in one of those
outside it.

2 Tt would be interesting to determine in future studies whether this uniformity

in distribution along a fault is a common feature of preparatory shocks. If so,
it would form some rough indication of the approach of a great earthquake.

Vol. 53.-] GREAT JAPANESE EARTHQUAKE OF 1891. 13

LV. DistRIBUTION OF THE AFTER-SHOCKS IN SPACE.

14, Prof. Omori has shown how the after-shocks decline in
frequency, rapidly at first and more slowly afterwards. This decline
is accompanied by more or less periodic fluctuations, and is occasion-
ally interrupted (as on September 7th, 1892) by strong or violent
earthquakes, each of which is followed by its own series of after-
shocks, which may cause a temporary rise in the total number.

That a somewhat similar law governs the area over which shocks
originate is evident from figs. 3-8 (pp. 5-7). During the first two
months the epicentres occur over nearly the whole fault-region, but
afterwards they are distributed over a more limited district, which
does not, however, continually decrease in size.

In order to ascertain roughly the rate of diminution of the area
of seismic action, I have made use of a series of monthly maps from
November 1891 to December 1892, and have in each case determined
the area included within the curve 5, which may be regarded as an
approximate, though not an accurate, measure of the area in question.
The results are given in the following table :—

Tape IIT.

Month. ee age ae igs Number of Epicentres.
Nov ISOU |. J.ec: 1741 11395
Deo Nee eee cee 935 495°5
Mame) NSO .24s02 930 284-5
Bisa c5scpetssaat 633 1405
PST set akaisciniape tats 572 U2)
PRED cay) [ace seis: 728 123
IVES Sp sk eetld se 543 96
BAITIGhe ky ~kdaetnges 444 72
UU are eeeeeeees 432 84
PME WS heats neice 473 95
Septet yg) occ use 546 156
OG ia eee 622 98°5
So) ae 727 103

| ec.) eee 467 86

The monthly number of after-shocks, already stated in Table I.
(p. 9),is repeated here for convenience of comparison. The figures in
both columns exhibit a fluctuating decline, but the area of seismic
action is not proportional to the number of shocks. We should not,
however, expect this to be the case, any more than we should
expect the area of the horizontal section of a hill made by the 500-
feet contour to be proportional to the total volume of the hill above
that plane.

15. Not only does the area of seismic action on the whole decrease
in size, but the seat of principal activity is subject to almost continual
change. Thus, the remarkable centre in the rectangle K sinks into

14 DR. CHARLES DAVISON ON THE [Feb, 1897,

comparative insignificance after the first two months, and gives
place to others in the rectangles EK and F, the order during the first
fourteen months being the following :—

KOK, FP, 8), 8, By Ee ee, 2, and) 2 (equal):

The maps themselves furnish the most interesting evidence of this
continuous displacement of the epicentres, though for details Table I.
should be consulted. One or two points may be referred to. Thus,
it will be seen that the rectangles C and D are more or less com-
plementary ; when one is the seat of action, the other is generally
in repose. So also, but to a much less extent, are the rectangles
K and F, one being as a rnle much more active than the other,
though they approach equality in this respect during the last three
months.”

Perhaps the most interesting result of all is the distribution of
epicentres along the main fault. A glance at the maps shows that
this is not continuous. In the two rectangles which intervene
diagonally between B and D there was almost complete repose,
except for the great earthquake, during the whole time considered,
there being only three epicentres within them in November 1891
and one in January 1892.” Again, in the rectangle G there is
another, though far less strongly-marked, break, which does not
occur, however, in December 1891 and April 1892, as will be seen
in figs. 8 & 5(pp.5 &6). Thus, the distribution along the fault may
be summed up as follows :—a nearly central region of extraordinary
activity, and two more or less isolated districts near or surrounding
the extremities of the fault.

The seismic activity of these terminal districts was not only less
marked, but also of shorter duration, than that of the central
district. At the northern end of the main fault, as well as at the
south-eastern end of its assumed continuation, all action practically
died out before April 1892. In the southern terminal region of
the fault-scarp it lasted until, if not after, the close of the same
year.

A similar withdrawal of action from its southern extremity
characterizes the secondary fault, only two epicentres lying in its
neighbourhood after March 1892. 3

The after-shocks of the Mino-Owari earthquake for the first
fourteen months were thus subject to the following conditions :—
decline in frequency, decrease in the area of seismic action, and a
gradual but oscillating withdrawal of that action to a more or less
central district.

1 These and other facts seem to show that the main fault is a system of two
or more rather than the single fault indicated by the scarp.

2 On September 7th, 1892, a strong earthquake occurred, which disturbed an
area of nearly 44,000 square miles. The rectangles most shaken lie along a line
passing immediately south-east of the B point and approximately at right angles
to the direction of the main fault. A transference of strain from the latter to a
possible longitudinal fault along the line indicated may perhaps account for the
comparative quiescence along this part of the main fault.

Vol: 5 3. | GREAT JAPANESE EARTHQUAKE OF 1891. 15

PostscRIPTUM.

[In the discussion which foliowed the reading of this paper, it
was stated that ‘where the maps showed blank spaces, in many
cases the country was mountainous, and there were no observers.’
This probably affords a partial, but not, I think, a complete expla-
nation of the paucity of epicentres in the district referred to herein,
for it would only apply to very slight earthquakes. It is obvious
that the stronger shocks (if there were any) originating within the
mountainous region would be observed in the surrounding country,
and the resulting records would enable the positions of the epicentres
to be determined.— Nov. 20th, 1896. ]

Discussion.

Prof. Mizner said that the Mino-Owari earthquake had furnished
a greater number and a more varied series of seismic phenomena for
analysis than had been noted in connexion with any disturbance
previously recorded. When this earthquake took place an enormous
fault, which can be traced over a length of more than 40 miles,
appeared upon the surface, and it was usually supposed that the
sudden rupture and displacement of vast masses of material along
this line were the cause of the earthquake.

On account of a peculiar distribution of shocks which took place
prior to 1891, Dr. Davison argued that the fault or faults in the
Mino-Owari district were outlined before the occurrence of the sreat
earthquake, which was, therefore, only the result of their extension.
This may have been so, but it must be remembered that before 1891
the number of shocks occurring in the Mino-Owari plain were not
numerous; and as we pass from 1889 to 1891 we cannot say that
they increased in number, while their distribution, as exhibited by
maps, was largely dependent upon the observing-stations. Where
the maps showed blank spaces, in many cases the country was
mountainous, and there were no observers. The present Author’s
method of treatment of the statistics relating to ‘ after-shocks’ no
doubt possesses advantages over that previously used by Prof. Omori,
but the results arrived at, so far as they are comparable, closely
accord. It was at the speaker’s suggestion that the study of after-
shocks was undertaken, and he must congratulate Prot. Omori on
having obtained results. far beyond and of greater importance than
anything anticipated at the outset. Prof. Omori added to our
knowledge respecting the expiring efforts in a seismic area; while
Dr. Davison, among other things, has thrown new light upon the
change in subterranean conditions which culminated, on October
28th, 1891, in a shaking which could be recorded from pole to pole.

The Rev. Epwry Hitt remarked upon the extreme interest of the
earthquakes described.

Mr. D. Patt also spoke.

16 PROF. T. G. BONNEY ON THE SECTIONS NEAR = [ Feb. 1897,

2. ApprtionaL Nore on the Sxcrions near the Summit of the FurKA
Pass (Switzertanp). By T. G. Bonney, D.Sc., LL.D., F.BS.,
V.P.G.S8., Professor of Geology in University College, London,
and Fellow of St. John’s College, Cambridge. (Read November
4th, 1896.)

In 1894 I gave an account* of certain sections in the valley of the
Reuss (Switzerland) where a somewhat schistose white marble is
associated with phyllites and limestones of Jurassicage. But of that
on the Furka Pass, as then stated, the description was incomplete, as
T had been compelled, owing to unfavourable weather. to be content
with a hurried glance at that part of the infold which is on the
western side of the summit. Here the road, curving round from a
W.S.W. to W.N.W. direction, cuts across the apparent strike of
the sedimentary rocks, and then quits them to run over the gneiss.
It was the western end of the triangle thus formed, a piece
measuring perhaps 400 yards in length by 250 at the widest part,
which I had been unable to examine. But in the summer of 1895
I walked up to the top of the pass from the valley of the Rhone, in
company with my friend the Rey. E. Hill, whose kind help I gladly
acknowledge, and completed the examination of the western side,
besides going over parts of the area which I had visited on the
former occasion. A few additional facts were obtained, which may
be worth bringing to the notice of the Society, for, although they are
not conclusive as to the relation of the marble to the Jurassic rock,
they throw, I think, some light upon the question.

On the western side of the pass, to speak first of the part left
unexamined on the previous occasion, the live rock in many places
is completely hidden by débris and turf. We have to make the best
of various outcrops, which become more isolated as we go west-
ward. The following account, however, I trust, is fairly correct.
The great mass of slabby marble,” mentioned in my former paper as
crossing the pass at the back of the ‘dépendance’ of the Furka Inn
and forming a crag above the road, appears to descend gradually
towards and run beneath the latter, and is lost under turf and talus
on the steep slope below. It is overlain® by a greyish sutcrystal-
line limestone, also rather slabby, with darker. more argillaceous
bands, which do not look at all crystalline. This rock in general
aspect corresponds with No. 3 of the section on p. 295 (op. cit.), and
reveals traces of organisms under the microscope. Higher up comes
a small outcrop of a rock which presents more resemblance to a
very crushed condition of the marble than to one of the ordinary

l Quart. Journ. Geol. Soe. vol. 1. (1894) p. 285.

2 No. 2 in the description given on p. 294 (op. cit.).

3 T speak throughout this paper of the apparent succession of the outcrops
on the mountain-slopes.

Vol. 53.] THE SUMMIT OF THE FURKA PASS, 17

Jurassic limestones. Thus I believe that the opinion expressed in
my former paper, as to a recurrence of the marble, is correct.
I was not, however, able to trace this second mass farther west.
‘The very rough diagram appended (fig. 1), a reproduction of one

Hie. I:

1 = Jurassic. 4 = Quite typical Jurassic: 12 to

2 = (Probably) crushed marble. 15 feet exposed.

3 = Small patch, probably crushed 5 = Marble (end of crag by road).
marble. 6 = Road.

[Intervening spaces mostly turf-covered. Rock, if any visible, Jurassic. |

drawn in my note-book to indicate the general relation of the rocks
on the western side of the top of the pass, may make the matter
clearer than copies of more detailed sections. Next comes more
limestone, grey or dark blue in colour, in one place having some
sandy bands, in another becoming clayey. ‘The details, however,
are without interest, and the rock is undoubtedly Jurassic. Lastly,
we found a pale-grey porphyritic gneissoid rock, with indications
of having been crushed; not improbably a modified granite. It
‘belongs, however, to the crystalline series of this part of the Alps,
and is much older than the Jurassic period. So far as one can
judge, the succession, which we observe close to the top of the pass,’
continues towards the west, except that the upper bed of marble seems
to disappear. The lower and larger mass is masked, after passing
beneath the road, by turf and talus, and, so far as I could see, does
not reappear. It is not indicated on the maps, and I think no
conspicuous outcrop occurs on the slopes of the glen west of the
pass.2. The dip of the above-mentioned rocks is variable in amount
and in direction, but something like 45° for the one and W.N.W.
for the other may serve as a rough approximation. The marble at
the top of the pass was more steeply inclined, having a dip nearer
70°; this, so far as I remember, was, however, rather exceptionally
high.

1 Op. eit. p. 295, ef. fig. 3.

? The slopes are steep and grassy, and exposures of rock mostly small. I
found at one place about 1400 feet above the Rhone Glacier Hotel a very small

outcrop which might possibly represent the marble in a greatly crushed condition.
But in this part I have not attempted to make a minute examination.

Q.3,G.8. No: 209. °. C

18 PROF. T. G. BONNEY ON THE SECTIONS NEAR _—‘ [ Feb. 1897,

At the time of my last visit the junction of the main mass of
marble with the overlying Jurassic rock could be seen at three
places. One is in a very small opening on the western side of the
pass, just beyond the end of the crag of marble overhanging the road.
Here we found in descending order (fig. 2) a subcrystalline lime-
stone weathering bluish-
grey, banded with a blackish
slaty rock, about 18 inches ;
‘black messy stuff’ (the
above slaty rock crushed),
about 6 inches; the slabby
marble (crushed). The two
other sections are on the
eastern side of the pass, and
Were exposed in small quar-
ries which had been opened
by the roadside since my
visitin 1894. The first was
about 120 yards from the
‘dépendance.’ Here we see
(1) a slabby, dull-coloured,
subcrystalline limestone,

1 = Marble, rather crushed.

parted by darker and more
argillaceous bands; (2) a
foot or so of ‘dark messy
stuff’ corresponding with

<x =Top slab: specimen taken.

2 = Suberystalline limestone with argil-
laceous slaty partings.

2'= Crushed slaty or shaly rock (‘black

messy stuff’), about 6 inches thick at

that in the last section ;
(3) the marble,* which rose
to a height of about 15 feet
above the road. Its surface has a somewhat wavy outline, and its-
upper part is evidently in a rather crushed condition. This is the
top of the mass of marble, which in 1891 we traced up the slope of
the valley below, and which passes behind the ‘ dépendance,’ forming
the crag by the roadside farther west. Two other smali pits, near
together, are found about 40 yards east of that just described, each
showing asimilar section. In all these exposures two rocks of very
different mineral character appear in close sequence, and suggest:
by their aspect some amount of faulting.

On previous visits I had observed certain macroscopic differences
between the marble and the admittedly Jurassic limestone, but on
this occasion became more than ever convinced of their existence.
The most important may be stated as follows:—The marble, if
unstained, is lighter in colour on a freshly-broken surface; on
weathered surfaces it turns to a pale fawn colour, with occasional
browner bands. These are more micaceous and project a little
from the rest of the rock. The Jurassic limestone is darker
in colour, becomes greyish-blue or bluish-grey in weathering, and

1 No. 2 of the section described on p. 294 (op. cit.).

Walts3.| THE SUMMIT OF THE FURKA PASS. 19

loses even its subcrystalline character in the more argillaceous
bands. Both rocks are ‘slabby,’ but this character seems due, in
the marble to pressure, in the limestone more immediately to the
presence of soft shaly layers, though it may have been augmented
by pressure. Moreover, to fracture a slab of the marble requires a
hard blow with the hammer. The other rock breaks more easily
and splits up into thinner slabs. In other words, the marble,
except perhaps within a few inches of the junction, in the zone of
exceptional crushing, is the less fissile of the two rocks. These
remarks apply especially to the most crystalline variety of the
Jurassic limestone, which appears, as stated in my former paper, to
come immediately above the marble. The rest of. it is so totally
different from the latter rock that no confusion can arise.

The distinctions which are observed in the field are confirmed by
study with the microscope. I collected some additional specimens
last year, which have been compared with those obtained on former
occasions. As regards the marble, I have really nothing to add to
my previous description. If allowance be made for the effects of
crushing (which are more conspicuous near the exterior), this rock
everywhere has marked characteristics of its own. The mica, when
it occurs, is usually well developed, seemingly authigenous, varying
from colourless to a pale brown tint; the grains of quartz (with no
hint of a fragmental origin) are larger than in the other rock; so
also are those of calcite, as well as being more uniform in size and
aspect. This rock, in short, corresponds very closely with the
marble and the purer parts of the calc-mica schists, which are so
abundant in association with various crystalline schists in many parts
of the Pennine Alps, not to mention other districts. Even the most
crystalline variety of the Jurassic rock is altogether less regular, and
_ generally is more fine-grained in structure than it; the mica is in
smaller flakes and of doubtful origin ; the calcite-grains vary much
in size, several certainly are fragments of organisms, among which
crinoidal structure occasionally can be recognized: here and there
dark films and small lenticles mark the presence of ‘ earthy ’ carbo-
naceous material, as in any ordinary impure limestone. Some
mineral changes have undoubtedly occurred; the quartz, for in-
stance, in its present form, does not indicate a clastic origin, but
the alteration never exceeds, if indeed it equals, that in the matrix
of the Jurassic ‘ knotenschiefer’ near the Nufenen Pass.!

Omitting for the moment one character, which has no immediate
bearing on the present question, we may thus sum up the dif-
ferences: that while both rocks have been affected to some extent
by pressure, the marble always seems tending to ally itself with
a thoroughly crystalline rock, such as elsewhere in the Alps would
be associated with typical mica-schists, quartz-schists, etc., and the
limestone with the ordinary members of the Jurassic system.

The subcrystalline limestone seems to occupy the same position
in regard to the marble, so far as it can be traced in this district,

1 Op, cit. p. 288, and vol, xlvi. (1890)-pp. 213-221. ‘
Cc

20 PROF. T. G. BONNEY ON THE SECTIONS NEAR [Feb. 1897,

and a second thinner and apparently more limited band of the
latter rock occurs above it. In the section at Realp! a rather
similar limestone overlies the slabby marble, but the second mass
of that rock is not seen. It may occur, however, for there is a
considerable interval of covered ground just where it ought to
crop out.

The possibility that this subcrystalline Jurassic rock might contain
small fragments of the marble has more than once occurred to me, but
on this point I have failed to obtain conclusive evidence. Here
and there one detects with the microscope single grains of calcite,
or associated groups of a few grains of calcite and quartz, which
present an approach to a definite boundary and resemble small
fragments of the marble; but, as the principal constituents of the
two rocks are the same, anything like a boundary-line is not easily
distinguished, and it may be that the agent, to which such meta-
morphism as the rock has undergone is due, has operated a little
sporadically. Still I think that this possibility should be kept
in view by anyone studying the rock. But the composition and
condition of the band in immediate contact with the marble, and the
state of the upper part of the latter, strongly suggest the existence
of a thrust-fault. That might follow, however, the direction of
the junction-surface between two rocks of different strength. But
whether the present succession of the rocks be the original one or be
only due to faulting, the result of this examination and of further
study of the rocks in the great trough of the Upper Rhone valley
convinces me that it is more probable that the marble is not a
member of the Jurassic system, but a much more ancient rock,
than that metamorphism has acted in a way unaccountably sporadic
and capricious.

Postscript.

This paper was completed shortly before I left England early in
July 1896. Most of my holiday was devoted to examining, in
company with my friend Mr. J. Eccles, F.G.S., sections between
Tlanz and Spliigen and the district south of the Rheinwald-Thal.
Hereabouts ‘slabby’ marble is an unusually abundant constituent —
of the group of calc-mica schists (including quartz-schists and
‘green schists’). The distinctive characters of the marble, and the
marked differences between this group of crystalline schists and
the slaty or calcareous rocks of Mesozoic age in the Alps, were
impressed, if possible, more strongly than ever, upon my mind.

Discussion.

The Rey. Epwin Hit said that he could speak only of the
Furka.section. The two rocks seemed always in conformity, but
always with signs of crush between, and always showed marked
differences in strength, pointing to difference in age.

1 Op, cit. p. 293, 3’ in the section.

Vol. 53.| THE SUMMIT OF THE FURKA PASS, - 21

Dr. J. W. Greeory thought that Prof. Bonney’s maintenance of
his former conclusion after a third study of the relations of the
saccharoidal and the Jurassic limestones would lessen the value
attached to the difficulties of his theory. Neither explanation
is free from difficulty, but the constant differences now found
between the two rocks greatly increase the probabilities in favour
of the fault-theory.
~The Avruor said that he quite agreed with Dr. Gregory that we
had a dilemma before us. We must either assume very peculiar
faulting or very sporadic and inexplicable metamorphism—seeing
that the marble was totally different from the adjacent Jurassic
rocks, was exactly like the ‘marbles elsewhere members of the
erystalline schists, and evidently had been affected by pressure after
it had become a marble, while the other was simply a limestone
affected by pressure. Hence he thought that the hypothesis of
faults offered the fewer difficulties.

22 MR. A. C, SEWARD ON CYCADEOIDEA GIGANTEA. [ Feo. 1897,

3. On CYCADEOIDEA GIGANTEA, a new CycapEan Siem from the
Purseck Beps of Porrranp. By A. C. Swann, Esq., M.A.,
F.G.8., University Lecturer in Botany, Cambridge. (Read
November 18th, 1896.)

[Puates I-V.]

Tue Isle of Portland has long been famous for the silicified Coni-
ferous and Cycadean plants which occur in the surface-soils of
Purbeck age. Buckland,’ Carruthers,? and others have described
the manner of occurrence and structure of the plant-remains
from this horizon, and the fossil ‘ crows’ nests,” or short, thick
stems of Cycads, have long been familiar to geologists. The plant
which forms the subject of the following description was acquired
by Dr. Woodward in 1895, and is

now one of the most remarkable Fig. 1.—WNSection of the quarry
specimens in the Fossil Plant Gal- — in which the Cycadean stem
lery of the British Museum.’ Itis was found.

probably the largest fossil Cycad
hitherto recorded, and although the
internal structure has been for the

—

slaty stone

most part very imperfectly pre- Shifling rubile
served, the cast of the stem is in
Ton slate
some respects unusually complete. =
aCycad Shaley clay

The specimen was found lying in a
horizontal position in a bed of
shaly clay, 2 feet thick, and about
17 feet higher in the Purbeck series
than the Great Dirt-bed, from which
most of the Portland plants have
been obtained.

The position of the fossil is shown ===
in fig. 1; the section is drawn from [| 26°\3====) Bur
a photograph of the rock-face in
one of Mr. Barnes’s quarries close to

——| Shinglebed
eee slaly stone

St. George’s Church on the west side Top cap
of the old Portland Wide Street.
; Lower ditt bed
In Pl. I. the stem is represented Sees

about 3 natural size; it measures [=
1 metre 18°5 cm. in height (nearly Wil beds 'y Roack

4 feet), and at the broadest part -diplland beds:

has a girth of 1m.7cm. Atthe — =

base it is somewhat narrower and [? OT en a chotoea i
thinner, and the. surface-features - ae

1 'W. Buckland, ‘Geology and Mineralogy considered with reference to
Natural Theology,’ Sixth Bridgewater Treatise, vol. i. (London, 1836) p. 490,
pls. lx—-Ixii.; also Trans. Geol. Soc. ser. 2, vol. ii. pt. iii. (1828) p. 395.

2 W. Carruthers, ‘On Fossil Cycadean Stems from the Secondary Rocks of
Britain,’ Trans, Linn. Soe. vol. xxvi. (1870) p. 675. > No. V. 3454.

Vol. 53.] MR. A. C. SEWARD ON CYCADEOIDEA GIGANTEA. 23

care less clearly shown than in the other portions of the stem. A
short distance above the base the preservation is particularly good,
and much of the internal structure of the peripheral tissues is fairly
well preserved. A transverse section has an elliptical outline (fig. 2),

Fig. 2.—Transverse section of the stem of Cycadeoidea gigantea,
Sp. nov.

Hie eatey
ASAT ANN PL pe
Ay A \\ a \ i) bal Cy gi TNH
YS a ANY \ Ml /
S \S \
=

measuring 41 cm. along the greater diameter, and 19 cm. along the
smaller. The section, as drawn in fig. 2, is taken from about the
middle of the stem; one side is almost flat, while the other has
a more distinctly convex form. The present shape of the stem is
no doubt largely the result of pressure, but it is possible that the
trunk was originally rather broadly oval than circular in section.

Covering the surface of the specimen there is the characteristic
ACycadean armour of the persistent bases of spirally-arranged leaf-
stalks. Among recent Cycads, the majority of species present an
appearance practically identical with that of the fossil, but in a few
living forms the surface of the stem has a very different appearance,
the regular petiole-bases being replaced by irregular transverse
ridges and corky protuberances. This less known and more un-
common form is well illustrated by such plants as Zamia Skinneri,
Warsz., Z. Loddigesit, Miq., and several others... In most Cycads,
however, after the fronds have withered, they become detached and
the lower portion of the petiole remains for a longer time on the
stem ; finally the ragged petiole is cut off by a clean surface covered
with corky tissue. The surface of the old stem in certain recent
genera is thus covered with the regularly-disposed persistent bases
of the large leaves. In the genus Cycas the stem shows a distinctly
marked alternation of large persistent bases of fronds, and smaller
‘bases of old bud-scales ; while in such a genus as Encephalartos the
bases of bud-scales and fronds present no such regular alternation,
and cannot be readily distinguished in the older portion of a large
stem. The surface of the fossil trunk is completely covered with
rhomboidal leaf-bases, approximately of the same size, and it is
impossible to draw any definite distinction between those of bud-
scales and the larger foliage-leaves.

1 See A.C. Seward, ‘Annals Bot.’ vol. x. no. xxxviii. (1896) p. 218, pl. xiv.
figs. 1 & 2.

24 MR. A. C, SEWARD ON CYCADEOIDEA GIGANTEA. [Feb. 1897;

Passing to the apex of the trunk, we find that the leaf-bases become
smaller in size (Pl. II. fig. 1), and finally at the extreme tip there is a
conical bud surrounded by several long and narrow bud-scales (fig. 3).
Covering the apex of the bud there is an irregularly-shaped cap of

whitish colour, of which the surface is marked by numerous wavy
lines suggestive of fine scaly or hair-like structures. The bud has
a height of about 3 or 4 cm., and the scale-leaves which are best seen
are about 1°5 cm. long and 6 mm, broad. The appearance of this
terminal bud is shown in Pl. I., and more clearly in Pl. II. fig. 1,
and in fig. 3. The lighter-coloured cap gives a flat-topped appear-

Fig. 3.— Apical bud of i pees gigantea, sp. nov.

SUN
Duy

nv y; AN?
pl % int eee

ance to the bud, and hides the tips of the uppermost scale-leaves ;
the form of the scales is, however, clearly seen in the lower portion
of the bud. It is important to note that the stem at the base of
the bud is almost circular in outline, thus confirming the opinion
that the flattened appearance shown in fig. 2 (p. 23) is in great
measure due to crushing. In the neighbourhood of the stem-apex
the surface-features are imperfectly preserved, but the leaf-bases are
distinctly visible in many places, and their gradual increase in size
as we pass down the stem is easily recognized.

44 it
Ih i

a
e . = oe ;
= a A =f Fc - Phan PES ~
ee =
= =
=

The material of which the specimen consists is highly siliceous ;
as shown in fig. 2, the central portion exhibits no trace of plant-
structure, and is composed of cherty rock, while at the periphery
the basal portion of the petioles and the interpetiolar substance are
more or less clearly seen, and are represented in the sketch by
radial lines extending inward a short distance (4 to 5 cm.) from the
surface. There are no traces on the stem of any large lateral buds
such as form so striking a feature in some fossil Cycadean plants,
as, for example, in Bennettites Gibsonianus, Carr., and in some of
the large specimens from North America and Italy.! An example
figured by McBride,” from Dakota, shows a number of lateral shoots

1 Capellini & Solms-Laubach, ‘Tronchi di Bennettitee,’ Mem. Real. Accad.
Sci. Istit. Bologna, [5], vol. ii. 1892, p. 3.
2 «The American Geologist,’ vol. xii. (1893) p. 248, pl. xi.

Vol. 53.] MR. A. C. SEWARD ON CYCADEOIDEA GIGANTEA. 25

with remarkable distinctness; he named this stem Bennettrtes
dacotensis, but Lester Ward has substituted the generic term
Cycadeoidea.* The distal ends of the persistent petiole-bases have
the form of rhomboidal areas, and the more internal portions ex-
tend for a short distance towards the centre of the stem in a
slightly upward direction. This is, at all events, the case in the
middle and lower portion of the specimen, but this position of the
petioles is probably to a large extent the result of the pressure of
overlying fronds, which has imparted to the bases a slightly down-
ward direction.

A closer examination of the surface-features and of the facts
revealed by microscopic sections of such peripheral tissues as have
been preserved brings out some interesting points, which enable us
to institute a comparison with recent plants and other fossil Cycads.
In Pl. II. fig. 2 a portion of the surface towards the lower part of
the trunk is shown on a larger scale. The appearance is that of a
strong and prominent network with rhomboidal or elliptical meshes ;
the upper and lower sides of each mesh assume in some places the
form of an are of a circle, and laterally each mesh is bounded by
the upper and lower walls meeting at an acute angle. The meshes
shown in the figure (on a reduced scale) have a breadth of about 3 cm.
and a height of 2em. In many cases the spaces in the network are
occupied by a plug of cherty rock which can occasionally be extracted
without difficulty ; in others there is a mass of crumbling brown dust,
while some are empty and extend for a short distance into the stem,
as cavities marking the position of the lowest portion of the petioles.
In some of the plugs occupying the meshes several small pits or
dots may be seen towards the periphery; these are, no doubt, the
remains of the vascular bundles of the leaf-stalk. In most cases,
however, the actual structure of the petioles has not been preserved
in any detail. The projecting framework frequently shows a
marked tendency to weather into flakes, and this is simply an ex-
pression of the fact that the ridges separating the petiole-bases are
largely made up of laminar structures, which are arranged in a
direction parallel to the surface of the petioles. These interpetiolar
structures are diagrammatically shown in PI. V. figs. 147, 16-18 r,
and more highly magnified in Pl. III. fig. 17, and figs. 4 & 8.
Sections cut through some of the projecting ridges, of which the
structure has been preserved by the infiltration of siliceous solutions,
enable us to make out some of the anatomical characters of the
petioles and the surrounding tissue composing the greater part of
the framework of the net. The petioles consist in the main of
fairly large-celled parenchymatous tissue, traversed by numerous
secretory canais and scattered vascular bundles. The position of
the secretory sacs or canals is indicated by the occurrence of dark
brown or almost black patches which represent the mineralized
contents of the secretory tissue. In Pl. V. figs. 16-18 the manner of

’ Proc. Biol. Soc. Washington, vol. ix. (1894) p. 86.

26 MR, A. C. SEWARD ON CYCADEOIDEA GIGANTEA. [TF eb. 1897,

occurrence of the secretory tissue is shown by the black dots; and
in the parenchyma of the petiole a, shown in fig. 14, the sacs are
seen in longitudinal section as obliquely-running and occasionally
anastomosing cavities. ‘The parenchymatous tissue of the leaf-stalk
is usually crushed and imperfect, but in places the preservation is
sufficiently good to show that the cells were of the ordinary type,
such as characterizes the fundamental tissue of recent Cycadean
petioles. In several of the parenchymatous cells of the ground-
tissue, and especially well seen in longitudinal sections, there occurs
a light-coloured vacuolated, or in some cases a darker granular
substance. A few of the cells enclosing such contents are shown
in Pl. IV. figs. 11-13; in the cell 6 (fig. 11) the brown contents
have a granular appearance, and lie in the cell-cavity as a slightly
contracted mass. In the cell c¢ the apparent granular substance
under a high magnifying power resolves itself into a fine reticulate
structure, the framework of the net being marked out by lines of
dark granules, and the meshes occupied by a brown substance. In
fig. 13 the whole cavity is filled with a lighter and more transparent
and delicate network, having rather the appearance of a number of
more or less spherical celis with clear contents. In fig. 11 d the
cell contains a spherical mass bounded by a delicate granular border,
and consisting of a brown material possessing a vacuolated or
frothy structure.

Again, in the neighbourhood of the larger sac (fig. 12) containing
the petrified secretion, the cells are occupied by a distinct reticulum.
The appearance presented by such a cell as d in fig. 11 and in
fig. 13 suggests the spores or cells of an endoparasitic organism, but
a careful comparison of several cells leads to the conclusion that
these various forms of vacuolated, frothy, and granular material are
merely different conditions of cell-contents. Prof. Marshall Ward
pointed out to me the very striking resemblance, or indeed identity,
between the contents of the fossil cells and the vacuolated and
frothy substance found in the parenchymatous tissue of many recent
plants. In a series of drawings of such cell-contents in some
recent members of the Rubiacew, made by Prof. Ward from material

which he investigated in Ceylon, it is possible to recognize the

several forms assumed by the cell-substance of the fossil parenchyma.
In the recent tissues these appearances are due to the various forms
assumed by tannin, oily and protoplasmic substances in the cells,
and in the fossil cells there can be little doubt that we have an
illustration of the preservation of similar cell-contents. The chief
importance of these facts is to emphasize the danger of regarding
such structures as the cells of foreign organisms. Among recent
plants this kind of cell-contents has been described as a parasitic
fungus, and the extraordinary manner in which some portions of the
vacuolated and frothy substance simulate the rounded cells of a
fungus, renders it easy to be misled by the deceptive appearance.
Precisely similar contents occur in the cells of the ground-tissue in
the petioles of Bennettites Gibsonianus.

It has recently been shown that the ‘spot disease’ of orchids is

Vol. 53.] MR. A. C, SEWARD ON CYCADEOIDEA GIGANTEA. 27

of a non-parasitic nature’; the contents of the leaf-cells of diseased
plants agree very closely with those in the fossil tissue. In a
paper contributed by Prof. Williamson in 1888 to the ‘ Annals of
Botany’ several examples are described of ‘anomalous cells’
within the tissues of Coal-Measure plants.” Some of the figures
of these structures are practically identical with the appearance
presented by the vacuolated contents in the cells of the Cycadean
petioles. A comparison, for example, of Williamson’s fig. 1
(pl. xvili.) with figures 11-13, Pl. IV. of this paper, and again
with Massee’s figure of the leaf-cells of a recent orchid, brings
out an exceedingly close agreement in both these cases. There is
very little doubt that many of these so-called ‘ cells’ in the tissues of
fossil plants are in reality vacuoles, granules, and other structures
which are probably pathological in their origin. Some may be
normal cell-contents, but others are more probably the expression
of some abnormal condition of the plant in which they occur.

In some of the parenchymatous cells in the petioles of the Port-
land fossil there are preserved small oval or spherical bodies which
stand out fairly conspicuously in the cell-cavity, as at n, Pl. IV.
fig. 11. It is not improbable that these are examples of fossil nuclei.

At the periphery of the petioles the ground-tissue passes
gradually into a parenchyma composed of somewhat smaller cells
(Pl. III. fig. 1), which assume a distinct radial arrangement.
External to these innermost radially disposed cells the tissue is
frequently broken across, but in places it has been left intact, and
is then seen to have the form of a zone of smaller, thinner-walled,
and flattened cells, which is evidently a band of meristematic tissue.
Beyond the cambium layer there is a succession of flatter and often
crushed cells in regular series, limited by a layer of indistinct and
partially disorganized cells (¢) representing the remnants of an
epidermis. In some parts of the section a light yellow-coloured
line (c) may be seen outside the epidermal cells, and this is in all
probability the imperfectly preserved and broken cuticle which has
in many places been detached from the cells of the epidermis. The
dark bands (p) at the margins of the petioles in Pl. V. figs. 16-18,
and the band (p) in fig. 14, are made up of SAEED rows of tan-
gentially-flattened cells.

In Pl. III. fig. 1 the lowest and largest cells g are part of the
parenchymatous ground-tissue of the petiole; next to these occur
rather smaller and radially-arranged cells, with cell-contents of a
bright sherry-colour, which may be described as phelloderm ( phd.)
formed on the inner side of the cork-cambium or phellogen (pAl.).
The break in the tissues represents approximately the position of
the cambium-cells, which would form a natural line of weakness.
External to this, we have the lighter-coloured and flatter cells ck.,
which constitute the cork-tissue developed from the phellogen.
The rich brown contents of the phelloderm-cells no doubt consist
of the silicified protoplasmic contents of this recently developed

1 G. Massee, ‘ Annals Bot.’ vol. ix. (1895) p. 421, pl. xv.
2 W. C. Williamson, ‘ Annals Bot.’ vol. i. (1888) p. 1, pl. xviii.

28 MR. A. C. SEWARD ON CYCADEOIDEA GIGANTEA. [Feb. 1897,

secondary tissue, while the absence of such infilling-material in the
cork tissue is in accordance with air-containing periderm-cells. The
epidermal cells are shown at ¢ in Pl. III. fig. 1, and what is probably
the remains of the cuticle at c. In fig. 3 the cork-cambium cells
are shown under a higher power. From the relative position of the
partially disorganized epidermis and its underlying periderm, it would
seem that the phellogen arose in the subepidermal cell-layer. In
Pl. ILI. fig. 2 is shown, on the same scale as fig. 1, a section through
the peripheral portion of a petiole of Macrozamia Denisoni, Moor &
Muell., cut from the persistent base of a leaf-stalk which has re-
mained attached to the stem after the fall of the frond. The larger
phelloderm-cells in the lower part of the section, phd., pass gradu-
ally into the parenchyma and the ground-tissue, g, and on the left
of the figure are seen four thick-walled sclerenchymatous cells, s.
External to the phelloderm there is the cork-cambium, followed by
the regular rows of flattened and somewhat crushed elements of the
cork, ck; finally the torn epidermis and thick cuticle are found in
the petiole-surface (e & c). In another part of the longitudinal
section, shown in Pl. V. fig. 14, the epidermis of the petioles has
been bent in such a manner as to appear in some places in surface-
view, in precisely the same way as, in a badly-cut transverse section
of a fresh leaf or twig, the epidermal layer is often bent over instead
of being cut through transversely. Where the epidermis has been
thus folded over, the component cells are seen to be polygonal or
square in form and to have straight walls, as in most recent Cycads.”
Several stomata stand out clearly, their position being readily recog-
nized by the occurrence of comparatively large and dark-coloured
guard-cells. In Pl. V. fig. 15 a stoma and some of the neighbouring
epidermal cells are represented ; the two conspicuous guard-cells, gd,
055 mm. in length, have somewhat shrunken cell-contents, and
the oval brown-coloured bodies in the lower cell bear a striking
resemblance to the chloroplasts in the guard-cells of recent stomata.
It is by no means impossible that the substance of the chlorophyll-
corpuscles has been preserved by the mineralizing material in such
a way as to retain in the fossil condition the original form and
arrangement of these constituents of the living cell.

The forms assumed by siliceous or calcareous substances in the
tissues of fossil plants are, however, often difficult to interpret, and
one cannot always determine how far the original cell-contents have
been the cause of the form assumed by the material in the petrified
cells. Between the two guard-cells, a small elliptical median
aperture is clearly seen, especially on focussing down to a slightly
lower level; this is the entrance to the respiratory cavity. On
either side of this there appears to be a subsidiary cell (s). As
no stoma is cut through vertically, it is difficult to be quite certain
as to the structures observed in surface-view ; possibly the apparently
lower cells, s, are really part of the inwardly curved guard-cells.

1 See Bornemann, ‘ Ueber organische Reste der Lettenkohlengruppe Thiirin-
gens, Leipzig, 1856; and Kraus, Pringsh. Jahrb. vol. iv. (1865-66).

Vol. 53.] MR. A. C. SEWARD ON CYCADEOIDEA GIGANTEA. 29

Kraus has figured a stoma of Ceratozamia mexicana * in which the
guard-cells are curiously curved in such a manner as to present an
appearance in surface-view similar to that of the fossil stoma.
Probably, however, the cells s are really separate from the guard-
cells, and in transverse section would appear very similar to the
stoma-cells of Cycas revoluta” as figured by Kraus, and later by
Strasburger.* The latter points out that Kraus’s section is neither
median nor vertical. On the whole the appearance in surface-view
and the size agree closely with those of the stomata of Dioon edule
and other Cycads; in Doon there are two subsidiary cells accom-
panying the guard-cells, and it is probable that there are two in the
stomata of the fossil petioles. So far as it is possible to decide, it
would appear that in the fossil the stomata are not much below the
level of the epidermis.

Scattered through the ground-tissue of the portion of the petiole 7,
shown in fig. 16, there are twelve imperfectly preserved vascular
bundles. The structure of the bundles appears to agree with that
described by Carruthers’ and Lignier® in species of Bennettites.
A single vascular bundle of Bennettites Gibsonianus is sbown in
Pl. IV. fig. 10, drawn from one of the sections of this plant in the
Jodrell Laboratory of the Royal Gardens, Kew. At cp there isa
group of tracheids without any regular arrangement, representing the
centripetal part of the xylem ; the probable position of the protoxylem
elements is shown at px. External to this there are other tracheids
more perfectly preserved and arranged in radial series (cf), with a
few separating rows of medullary-ray cells (m). This portion of
the bundle constitutes its centrifugally-developed xylem. Beyond
this the tissues are as a rule less perfectly preserved, but in some of
the sections of Bennettites it is easy to make out a line of thin-walled
cambium-cells succeeded by the crushed elements of the phloem.
Next to the zone of crushed phloem, there is a group of more clearly
preserved cells (s), which may have been sclerenchymatous ; they
correspond to the thick-walled elements which Bertrand and Lignier
have designated the ‘ fibres primitives’"; probably, however, these
cells do not form part of the true vascular bundle, but belong to
the ground-tissue of the petiole. In Pl. IV. fig. 9, one of the
vascular bundles of the Portland stem is represented ; although the
preservation of the tissues is imperfect, the structure is sufficiently
good to enable us to recognize a close agreement with the bundles
of Bennettites Gibsonianus. The line ¢ marks the external limit of
the centrifugal xylem and the position of the cambium. External
to this is the crushed phloem (ph), and finally a few cells, s, corre-

1 Kraus, ‘Ueber den Bau der Cycadeenfiedern,’ Pringsh. Jahrb. vol. iv.
(1865-66) pl. xxi. fig. 20.

2 Ibid. pl. xix. fig. 5.

° Strasburger, ‘ Hin Beitrag zur Entwicklungsgeschichte der Spaltéffnungen,’
Pringsh. Jahrb. vol. v. (1866-67) p. 331, pl. xli. fig. 143.

* Not shown in the figure.

5 Trans. Linn. Soe. vol. xxvi. (1870) pl. lx. fig. 7.

6 ‘Structure et Affinités du Bennettites Morterei (Sap. & Mar.),’ Mém. Soc.
Linn. Normandie, vol. xviii. (1894) p. 21, pl. i. fig. 18, ete.

7 Lignier, op. swpra cit. p. 21.

30 MR. A. C, SEWARD ON CYCADEOIDEA GIGANTEA, [ Feb. 1897,

sponding to those on the outside of the Bennettites-bundle (Pl. IV.
fig. 10). The dark radial lines, m, are no doubt rows of medullary-
ray parenchymatous cells. Below the radially-disposed tracheids,
the tissue is very indistinct and disorganized, but probably there
was in this position a group of centripetal tracheids corresponding
to those shown at cp in fig. 10. In longitudinal section the
imperfect xylem elements are seen to have scalariform thickenings
on their walls.

It has already been pointed out that the spaces between the
petiole-bases are occupied by a mass of scaly structures or ramenta.
In transverse section the ramenta have the form of short and tapered
cell-rows, more or less closely crowded together between the petioles.
Longitudinal sections through the petioles show the ramenta attached
here and there to the epidermal layer, from which they arise as
laminar outgrowths. In Pl. V. fig. 14 the ramenta are seen to curve
towards the leaf-stalk surfaces at «, whereas in the greater part of
the space between the petioles they occur as closely-crowded
lamine, 7, parallel to the petiole-bases. In Pl. III. figs. 1, 4, & 8,
some ramenta are shown in transverse section ; they have the form
of a single layer of cells, or in the median portion they may be
two, three, or more cells thick. The largest in fig. 4 has a length
of *75 mm. and a breadth in the middle of ‘1 mm. In the longi-
tudinal section the cells of the ramenta are long and narrow, with
fairly squareends. Precisely similar structures have been previously
described and figured by Carruthers and others, as forming a kind
of interpetiolar packing in Bennettites... The ramentum shown in
Pl. III. fig. 7 was drawn from a section of B. Gibsonianus ; it is
shorter and broader than most of these structures, which are
practically identical in form in the Portland stem, in Bennettites
Gibsonianus, and B. Morierer.2 Nodoubt the compact and crowded
arrangement of these epidermal structures between the petiole-bases
has been partly brought about by the development of cork, and the
consequent increase in thickness in the persistent leaf-bases. The
projecting network shown in the photograph, Pl. I. and Pl. II.
fig. 2,is chiefly made up of silicified ramental tissue, and exactly the
same is the case in Bennettites Gebsonvanus and other fossil trunks:
The crowded and narrow cellular plates apparently absorbed the
mineralizing-solution more readily than the tissues of the petioles,
and so resisted decay, while the substance of the petioles has been
for the most part destroyed. The comparatively loose mass of
ramenta probably acted like a sponge, and sucked up the siliceous
solutions with avidity. In speaking of these scaly outgrowths
covering the basal portions of the petioles in Bennettites, Graf Solms *
has called attention to the striking resemblance which they bear to:
the ramenta or palez so abundant on the leaf-stalks of many ferns.

1 Cp. Carruthers’s figures (op. gam cit.), pl. 1x. figs. 7 & 11.

2 Lignier, op. cit. pl. i. figs. 10-13.

-3 Solms-Laubach, ‘ On the Fructification of Bennettites Gibsonianus, Carr.,
Annal. Bot. vol. v. (1890-91) p. 423.

Vol. 53.] MR. A. C. SEWARD ON CYCADEOIDEA GIGANTEA. 3l

Carruthers thus describes the occurrence of the interpetiolar
scaly structures in Bennettites :—‘ A very dense ramentum clothed
the under-surface of the base of the petiole, which was developed
to such an extent as to separate very considerably each petiole from
its neighbour. The petrifying material, having obtained speedy
access to these delicate scales, has preserved them in a remarkably
perfect condition.’ *

In Pl. III. fig. 5 a single ramentum from the petiole of Cyathea
excelsa, Sw., is shown in transverse section. This is a typical
example of a fern-ramentum, and the resemblance to the corre-
sponding structures in the fossil Cycad is obvious. The ramenta of
ferns are occasionally more than one cell! thick, as in those of the
fossil Cycadean petioles. In a few ferns, e. g. Dicksonia antarctica,
Lub., and Osmunda regalis, L.,* the paleze have the form of cell-
filaments, but this is exceptional. In recent Cycads, on the other
hand, the woolly covering which is conspicuous on the bud-scales
and leaf-stalk bases of some species consists of very long hairs com-
posed almost entirely of a single cell. Buckland, in the sixth
‘Bridgewater Treatise,’ figured a section through the basal portion
of a recent Cycad, showing the woolly epidermal hairs, comparable
to the outgrowths from the fossil leaf-stalks (pl. lxii.). In Pl. ITT.
fig. 6 a portion of one of the long hairs of Dioon edule, Lind., is
represented ; it consists of a short, thick-walled stalk-cell with a very
long terminal cell. In the bud-scales and carpophylls of the cone
of the same species, the dense covering of woolly hairs is very
conspicuous. Similar hairs occur alsoin Macrozamia, Encephalartos,
and other recent Cycads.* These ramental hairs of Cycads and the
chaffy scales of fern-petioles are used in New South Wales as
stuffing for cushions and known as ‘ pulu.’

Reverting to the terminal bud of the fossil stem, it has already
been pointed out that the apex is covered by an irregularly-shaped
cap of ramental tissue. In fig. 4 (p. 32) is represented the apical bud
of a large plant of Encephalartos Altenstemi, Lehm., in the Royal
Gardens, Kew ; in the lower portion the narrow and pointed bud-
scales are clearly shown, but the summit is capped by a loose woolly
mass of long brown hairs.* The resemblance between the bud of
the recent and fossil stems is particularly striking. A few months
after the photograph, reproduced in fig. 4, was taken, the hairy
covering and bud-scales were seen to be pushed aside by the elon-
gation and expansion of a large male flower. Whether the fossil
bud, at the time of the plant’s death, contained a crown of unde-

1 Trans. Linn. Soc. vol. xxvi. (1870), p. 696.

? Campbell, ‘The Structure and Development of the Mosses and Ferns,’
1875, p. 353. See also De Bary, ‘ Comparative Anatomy,’ p. 64.

3 For other instances of the occurrence of hairs or cell-laminz on the leaves:
of fossil Cycadean plants, see ‘The Wealden Flora,’ vol. ii. (Brit. Mus. Cat.
1895), ‘ Bennetiites, passim. See also Eichler on Cycadacee, in Engler &
Prantl’s ‘ Die natiirlichen Pflanzenfamilien,’ pt. ii. (1889).

* My thanks are due to the Director of the Royal Gardens for permission to
have photographs prepared for comparison with the fossil plant.

32 MR. A. C. SEWARD ON CYCADEOIDEA GIGANTHA, [Feb. 1897,

veloped fronds or a floral shoot must unfortunately remain a
matter for speculation.'

It remains for us to consider more fully the affinities of the
Portland fossil stem. Externally it would be difficult to discover
any real difference between the fossil and many large trunks of
recent Cycads, especially some species of Macrozamia and Encephal-
artos. Inrecent stems, the
older petiole-bases may be Fig. 4.—The apical bud of Encephal-
frequently seen to have artos Altensteinii.
rotted away internally, _—
while a peripheral band of :
more resistant material,
periderm or sclerenchyma,
has remained as a project-
ing ridge.” In the fossil
stem it is more particularly
the interpetiolar tissues
that have remained as the
prominent surface-feature.

Passing to the internal
structure, there is a close
correspondence between the
fossil petioles and those of
living Cycads. In a trans-
verse section of a recent 2 oy
petiole taken some inches oa 3
above the base, there is a [From a photograph of a plant in the Palm
well-developed hypodermal House, Royal Gardens, Kew.]
mass of sclerenchyma in-
terspersed with groups of thin-walled parenchyma. If a series of
sections be cut from a petiole until the base is reached, the scleren-
chymatous hypoderm is found to gradually decrease in amount, and
is finally almost or entirely absent. A cork-cambium arises in the
persistent basal portion, either in the subepidermal layer or ina deeper
layer of cells, and a ring of periderm is developed. This increase

in the diameter of the old leaf-bases of Cycads has been alluded to

by Saporta,? Renault,’ Solms-Laubach,’ and others. In the fossil
stems we have an exactly similar formation of periderm in the
petiole-bases. The leaf-bases of Dioon edule, as well as those of
the species of Macrozamia (M. Denisonz) figured in Pl. III. fig. 2,
illustrate very clearly the disappearance of the sclerenchyma and the
formation of cork. In Dioon edule the phellogen occurs internal

1 Lester Ward has pointed out (U.S. Geol. Surv., 16th Ann. Rep. 1896,
p. 487) that one of the specimens of Benmettites (Cycadeoidea) Saxbyana in the
British Museum possesses an apical leaf-bud. This, however, is very much less
distinct than the bud in the Portland stem.

2 This is particularly well shown in a piece of a stem of Macrozamia
Moorei in the Museum, Kew Gardens.

3 Pal. Franc. vol. ii. (1875), Cycadées, p. 11.

4 ©Cours de Bot. foss.’ vol. i. (1885) p. 35.

5 ‘Die Sprossfolge der Stangeria u. der iibrigen Cycadeen,’ Bot. Zeit., Jahrg.
xlviii. p. 12. See also Hichler in Engler & Prantl, op. jam cit. p. 7.

Vol. 53.] MR. A. C. SEWARD ON CYCADEOIDEA GIGANTEA,. 33

to the hypodermal sclerenchyma; in Macrozamia Denisoni, imme-
diately underneath the epidermis. Some of the petioles seen on the
polished tangential surface of a large block of Bennettites Giibson-
zanus in the British Museum possess a peripheral band of darker
tissue, which is probably periderm. In the leaf-bases of B. Gubson-
zanus, in the immediate neighbourhood of the lateral inflorescences,
there is no cork or sclerenchyma ; in such cases the petioles would
retain the power of further growth by cell-division.

The identity of the ramenta with those of Bennettites has already
been emphasized, also the apparently close resemblance between the
vascular bundles. Without discussing at length the comparative
structure of the vascular bundles of recent and fossil Cycadean
petioles, it is advisable to draw attention to one or two important
features. ‘ In a transverse section of a Cycadean leaf-stalk, we find
the vascular bundles are distinctly collateral in form, with the proto-
xylem elements on that side of the xylem next the phloem. The
main portion of the xylem consists of tracheids internal to the proto-
xylem, which have been developed centripetally ; external to the
protoxylem, however, there occur a few isolated tracheids, or in
some cases a fairly thick, crescent-shaped band, developed in a
centrifugal direction." Bundles in which the primary xylem is both
centripetal and centrifugal have been termed mesarch. The nature
of such bundles has been discussed by Solms-Laubach in his
* Fossil Botany’ (p. 257), and more recently by Williamson and
Scott (Phil. Trans. vol. clxxxvi. 1895, B, p. 713). If we examine a
petiolar vascular bundle in the basal portion of a frond-axis, the
centripetal portion of the xylem is found to be much more con-
spicuous than in the upper part of the petiole, and composed of
radially-arranged tracheids. This is seen to be the case in Macro-
zamia Denisoni, and Mettenius figures a good example of such a
bundle in the petiole of Cycas revoluta.*”, A comparison, therefore,
of the fossil vascular bundles with those in the basal portions of
recent petioles shows a fairly close agreement. There is still need,
however, of a more accurate knowledge as to the anatomy of the
recent Cycadean vascular bundle and its exact relation to that of
Bennettites and other fossils. The chief difference between the
fossil and recent bundles seems to consist in the more considerable
development in the former of the centrifugal portion of the xylem.

The genus Bennettites has frequently been referred to in the
description of the Portland stem ; this generic name was proposed by
Carruthers in 1870 for stems possessing the following characters :—
« Trunk ovoid, in transverse section elliptical, covered with the some-
what long permanent bases of the petioles. Medulla entirely cellular,
with numerous gum-canals. Wood consisting of a thin interrupted

1 These centrifugal tracheids are shown in a figure of Cycas revoluta, in De
Bary’s ‘ Comparative Anatomy’ (1884), p. 336. See also Mettenius, ‘ Beitrage
zur Anatomie der Cycadeen,’ Abh. k. sachs. Gesellsch. Wissensch. 1860 ; Kraus,
Pringsh. Jahrb. vol. iv. 1865-66, ete. The petioles of Cycas media, Br., and
Dioon edule, show a larger development of these centrifugal tracheids than is
found in some other species. 2 Mettenius, op. supra cit, pl. i. fig. 7 (d).

Q.J.G.8. No. 209. D

34 MR. A. C. SEWARD ON CYCADEOIDEA GIGANTEA. [Feb. 1397,

cylinder of striated tissue everywhere penetrated by medullary rays.
Fruits borne on secondary axis not protruding beyond the bases of
the petioles.’ *

The elliptical form of the stem in transverse section is a character
of somewhat doubtful value, and should not be regarded as @
feature of primary importance, owing to the difficulty of determining
how far such a form is due to secondary causes. In an important
morograph on Italian Cyeadean fossil stems, Solms-Laubach uses the
generic name Bennettites for such stems as possess the lateral
inflorescences, showing the characteristic features which have been so
fully described in the case of B. Gibsonianus, Carr.2? The important
difference between the present fossil stem and B. Gibsonianus
consists in the absence in the former of any lateral inflorescences.
A careful examination of the surface of the trunk has failed to reveal
any indication of the small flattened bracts which surround the
inflorescence of Benettites. In other respects there is the closest
agreement between the large Portland trunk and B. Gibsonianus.
Seeing that the surface-features are imperiectly preserved, it would
be rash, on the strength of negative evidence, to assume that in the
stem before us the flowers were produced at the apex as in recent
species. The evidence, indeed, so far as it goes, tends to support
such an assumption.

Insuch species as B. Gabsonianus and B.(Cycadeoidea) portlandicus
(Carr.)° the lateral inflorescences are easily seen on the stem-surface,
and if such existed in the present specimen one would certainly:
expect to find traces of them among the casts of the leaf-stalk bases.

Although no trace has been found of a lateral inflorescence of
the Bennettitean type, a small bud was discovered in a tangential
section taken from the lower portion of the stem. In Pl. Y. fig. 16
a tangential section is shown, slightly enlarged, in which portions
of three petioles are seen separated by the densely-packed ramenta, r..
At 6 a smaller oval structure, 8 mm. in length, is cut across trans-
versely; it consists in the main of parenchymatous tissue with
numerous secretory sacs.

At the periphery of 6 the epidermis and cuticle are distinct, with.
some ramenta seen in connexion with the surface-cells. Below the
epidermis the tissue consists of flat and crushed cells, which by their
apparently radial arrangement suggest periderm. Next to this.
band yp’ there is parenchyma with numerous secretory sacs. At p’
there is a band of tissue similar to p’, and consisting of radially-
disposed cells. The centre is occupied by parenchyma containing.
numerous secretory cells with dark-coloured contents.

In the parenchymatous tissue occasional groups of smaller:
elements are seen, which may be vascular bundles. From this- -
section alone it seemed impossible to interpret the meaning of the
structure 6 embedded in the mass of ramental tissue. In figs. 17
& 18 two more sections are represented, which were cut parallel.

1 Carruthers, Trans. Linn. Soe. vol. xxvi. (1870) p. 694.
2 For a general account of Bennettites, see Cat. Brit. Mus. ‘ Wealden Flora,”
vol. 11. (1895) pp. 134 et segg. ? Carruthers, op. supra cit. pl. 1xi.

=

Vol. 53.] MR. A. C, SEWARD ON CYCADEOIDEA GIGANTEA. 30

with, and slightly external to, that shown in fig.16. In the second
section, fig. 17, in place of the solid group of tissue, we find a
number of long, narrow, and irregularly-shaped structures, more
clearly seen in fig. 19, which are no doubt young leaves spirally
arranged round the axis, av. The whole group is 7 mm. in length.
The leaf-sections consist of parenchyma containing many secretory
cells, and external to these bract-like appendages there occur
numerous ramenta. ‘The entire structure is evidently a bud cut
across somewhat obliquely. Finally, in fig. 18, the bud is no longer
visible, but its position is indicated by the twisted and sinuous form
of the ramenta, which suggests—to use a far-fetched simile—the
swirling eddies of water over a sunken rock. The apex of the bud
was no doubt clothed with ramental appendages, and it is these
covering and protecting structures that are seen at 6’ in fig. 18.
The oval section 6 in fig. 16 may be regarded, therefore, as the
stalk of a small and apparently vegetative bud, of which the indi-
vidual leaves are shown in fig. 176 and fig. 19. The whole structure
is evidently a dormant and aborted lateral bud. In recent Cycads
such lateral shoots are often seen in species of Cycas,' and less
commonly in Encephalartos and other genera. — It is indeed possible.
that the bud may be that of an inflorescence, but there is no
decisive evidence as to its exact nature.

A plant of Encephalartos Altensteinii in the Palm House at Kew
shows a large lateral branch bearing a well-developed crown of
leaves. Zamia Skinneri, Warsz., and other species of the same
genus, afford striking examples of branched Cycadean stems.

In a recent revision of Buckland’s genus Cycadeoidea, Lester
Ward* has included in that comprehensive generic designation
Carruthers’s genus Bennettites. There are, however, certain reasons,
as shown by Solms-Laubach, which favour his use of the genus
Benneitites, according to which it is restricted to such stems as
possess undoubted inflorescences of the type described in the case of
B. Gibsonianus.’ Without entering further into this question of
nomenclature, there can be little doubt that Cycadeoidea is the
most appropriate generic name for the stem described in the present
paper. It is proposed to name the specimen Cycadeoidea gigantea.

The following diagnosis is necessarily incomplete, as the pre-
servation of the specimen is not such as to permit of a thorough
investigation :—

Genus CycapEomEaA, Buckland, 1827.

OCycadeoidea gigantea, sp. nov. ‘Type specimen in the British
Museum. (Wo. V. 3454.) Acquired Oct. 1895. From the Upper
Purbeck, Isle of Portland.

Stem terminating in an apical bud, covered with long and narrow

1 Goppert in 1844 figured a good example of such buds in a paper on fossil
Cycads, Schles. Gesellseh. Denkschr. 1853, p. 251. In his figure of Rawmeria
Schulziana, Gopp. (pl. vii), the ramenta appear to be of the same form as those
figured in Pl. IE. of the present paper.

2 Ward, Proc. Bicl. Soc. Washington, vol. ix. (1894) p. 75.

3 Cat. Brit. Mus. ‘ Wealden. Flora,’ vol. ii. (1895) p. 139.

D2

36 MR. A. C, SEWARD ON CYCADEOIDEA GIGANTEA. [Feb. 1897,

bud-scales, and covered with ramental outgrowths. The older part
of the stem is surrounded by an armour of persistent petiole-bases .
separated one from another by a dense mass of ramenta. The
petioles composed of parenchymatous ground-tissue with numerous
secretory cells, and traversed by scattered and comparatively large
collateral vascular bundles ; the centrifugally-developed xylem forms
the most conspicuous part of each bundle, and consists of radially-
arranged rows of pitted tracheids, with a few rows of medullary-
ray cells. At the periphery of the petioles there is a fairly thick
band of phelloderm and periderm, the phellogen being found in
the subepidermal layer. The epidermis is provided with a distinct
cuticle, and stomata consisting of two guard-cells and probably two
subsidiary cells, slightly bent below the level of the epidermis.
The ramenta arise as epidermal outgrowths in the form of plates
of elongated parenchymatous cells; they may consist of a single
layer of cells, or in the median portion they may be several cells in
thickness. No trace of any lateral inflorescence such as occurs in
Bennettites. Fronds unknown.

As already stated, the points of agreement between Cycadeoidea
gigantea and Bennettites are very clear, with the exception of the
absence, or apparent absence, in the former of any lateral inflores-
cence. It is unnecessary to recapitulate the characteristic features
of Bennettites which mark it off as distinct in certain particulars from
the recent family Cycadacee, but it is important to bear in mind
that in speaking of fossil Cycads we include other forms than those
which strictly conform to the characters of the present genera. It
has been rightly said. that we have as yet no well-authenticated
case of a fossil stem which may with certainty be placed in the
Cycadaceze * as at present defined. As regards the exact affinities
of Cycadeoidea gigantea, it is impossible to speak with certainty as
to its natural position without more complete evidence. In the
absence of the reproductive organs we must be content with such
evidence as is afforded by the vegetative structures. There is no
sufficient reason for regarding the stem as essentially distinct from
such a type as is represented by Bennettites Gabsonianus, so far as
concerns its position in a system of classification.

It is to be hoped that more material may be obtained which will
enable us to supply some of the lacunz in the above description,
and to decide whether Cycadeoidea gigantea agrees in its floral
structures with existing Cycads or with the true Bennettites, which
can only be included among Cycadean plants if the term Cycad be
used in an extremely wide sense. The point of contact between
Cycadeoidea gigantea and species of Bennettites on the one hand, and
recent ferns on the other, which is afforded by the ramental scales,
although perhaps a small one, is of interest when considered in
connexion with some other fossil genera. The genera Lyginoden-
dron, Heterangium, Myeloxylon, of Paleozoic age, are good examples
of plants in which Cycadean and Filicinean characters are combined

1 Solms-Laubach, ‘ Annals Bot.’ vol. v. (1890-91) p. 425.

Vol. 53.] MR. A. C. SEWARD ON CYCADEOIDEA GIGANTEA. 37

in a striking manner, and they furnish undoubted evidence of a very
close alliance of Ferns and Cycads in an earlier stage of plant-
evolution. In all probability these synthetic forms warrant the
conclusion that the characteristic features of existing Cycadean
plants have been derived from an ancient fern-like stock.’ It is
of interest, therefore, to discover in the ramental scales of Mesozoic
Cycadean species a remnant of this relationship between the two
sets of plants ; although in the structure of its reproductive organs
the genus Bennettites has advanced a stage beyond that repre-
sented by recent Cycads. In describing a section of Rachiopteris
Willamsoni in 1894, I referred to the occurrence of a mass ot
parenchymatous tissue attached to the surface of the petiole, con-
sisting of thin-walled and elongated parenchymatous cells. Probably
this tissue is of the same nature as the pales on the petioles of recent
ferns, and the #aminar outgrowths in Bennettites and Cycadeoidea
gegantea. LRachiopteris Walliamsoni, as Scott and Williamson have
suggested, should probably be included in the list of plants which
occupy a position in the borderland between fern-like and Cycadean
forms. Unfortunately we have as yet no evidence of the form of
the fronds which crowned the stem of Cycadeoidea gigantea. The
palzobotanist must often perforce be content to describe leaves and
stems under separate names, and wait for additional evidence as to

the connexion between the detached fossil portions of the same
plant.

My thanks are due to Mr. Gepp, of the Botanical Department,
British Museum, for the photographs reproduced in Pls. I. & II. ;
and to Dr. Henry Woodward I am indebted for facilities afforded
me in the examination of the British Museum specimens. Mr.
H. H. W. Pearson, of Christ’s College, has rendered me valuable
assistance in the preparation of sections of recent plants.

EXPLANATION OF PLATES I.-Y.

(The sections of Cycadcoidea gigantea, twelve in number, are in the Geological
Department of the British Museum, Natural History.)

Prate I,

Cycadeoidea gigantea, $ nat. size. (From a photograph by
Mr. Gepp, of the British Museum.)

Puate II,

Fig. 1. The apex of the stem shown in Pl. I. About + nat. size.
2. Leaf-bases and ramenta from the lower portion of the stem. (Both
figures from Mr. Gepp’s photographs.) About 4 nat. size.

* On this question see Williamson & Scott, Phil. Trans. vol. elxxxvi. (1895)
p- 770. As regards the connexion between recent Cycads and Ferns, see Hichler,
in Engler & Prantl’s ‘ Die natiirlichen Pflanzenfamilien,’ pt. ii. (1889) p. 20.

2 “Annals Bot.’ vol. viii. no, xxx. (1894) p. 209, pl. xiii. fig. 2a.

38 MR. A C, SEWARD ON CYCADEOIDEA @IganTEA. [Feb. 1897,
Puate III.

Fig. 1. Transverse section through the periderm of a petiole of Cycadeoidea

gigantea. (X 52.) r=ramenta; c=cuticle; e=epidermis;

ck=cork; phi=phellogen ; phd=phelloderm ; g=ground-tissue.
2. Transverse section of the periderm of Macrozamia Denisoni, Lettering
as in fig. 1. (xX 52.) s=sclerenchymatous cells.
3. Cells of the cork-cambium (phellogen) of fig. 1 more highly magnified.
x 230.
Figs. 4 & é Sata of Cycadeoidea gigantea in transverse section. (X 52.)
Fig. 5. Single ramental layer of Cyathea excelsa. (X 52.)
6. Epidermal hair of Dioon edule. (x 280.)
7. Ramentum of Bennettites Gibsonianus, Carr. (xX 52.)

Puate LY.

Fig. 9. Vascular bundle of a petiole of Cycadeoidea gigantea. (X 320.) s=
sclerenchyma (?); ph=crushed phloem; c=campium ; ¢f=centri-
fugal wood ; m=medullary rays. .

10. Vascular bundle of Bennettites Gibsonianus. px=protoxylem ; cp=

centripetal xylem. Other lettering asin fig. 1. (x 320.)

Figs. 11,12, &13. Cells of the parenchymatous ground-tissue of the petiole a
shown in fig. 14. m=nucleus(?). Fig. 12(x 230). Figs. 11 &13
(x 355). Reduced one-half from the original drawing.

PuatTe V.

Fig. 14. Longitudinal section showing portions of the petioles and an inter-
vening mass of ramenta. (x 17.) a=upper petiole, with
parenchyma and secretory cells of the fundamental tissue. p=

eriderm, including phelloderm and cork; x=junction of ramenta
with the epidermis ; r=ramenta.
15. Stoma, with guard-cells and pore; also a few epidermal cells showing
the form of the walls. gd=guard-cells; s=subsidiary cells.

Figs. 16-18. Semi-diagrammatic sketches slightly enlarged (fig. 16—section
16x2 em., fig. 17—2:1x 1°35 em., fig. 18—2°3x1°8 cm.), showing
portions of petioles, ramental tissue, and bud, 0.

Fig. 19. Section of the hud as shown at 0 in fig. 17. (x 24.) ax=axis of
bud, surrounded by leaves and ramenta. Reduced one-third from
the original drawing.

Discussion.

Dr. D. H. Scorr thought that this paper was of the greatest
interest. Nothing was more remarkable in paleobotany than the
prevalence during the Mesozoic period of plants which exactly
resembled existing Cycadez in habit and external characters, but
which, in the best known cases, differed absolutely from them as
regarded their fructification. This was the case notably with
Bennettites, investigated by Carruthers, Solms-Laubach, and Lignier,
which bore reproductive organs totally unlike those of Cycadeex or
any other known gymnosperms, and approaching in some respects
those of angiosperms. The existence of the Bennettiteze and certain
other fossil groups showed that our recent Cycads form only a small
surviving family, representing what was once an extensive and varied
class of plants.

Tt was an interesting question, to which group of Cycad-like plants
the fine specimen described by the Author belonged. ‘The ramenta

‘Vol. 53.] MR. A. C., SEWARD ON CYCADEOIDEA GIGANTEA, 39

afforded a minute but important character, strongly indicating
Bennettitean affinities. Possibly the small lateral bud described by
the Author might have been an abortive fructitfication.

The preservation of histological structure in the external tissues,
as demonstrated by the Author, was astonishingly perfect, and had
rarely been equalled in fossil plants. As regards the branching of
recent Cycadezx, it was well known that many of them branched
far more freely in nature than when cultivated in our hot-
houses.

Prof. Tats intimated that Australia might be thought to offer a
field of investigation in the evolution of the Cycadex, but unhappily
no such plants (at least none acceptable to the botanist) occur in the
Kainozoic strata, which contain at various horizons extensive
terrestrial formations. From field-observations on some Australian
species of Encephalartos, notably EL. Macdonnelli, he could not concur
with the statement that the trunk was subject to furcation.

Prof. SzeLey stated that he had examined specimens of Cycad
stems in the Isle of Portland and in the Wealden Beds, and one
specimen from the Potton Beds, which appear to have been vertical,
and were all more or less ovate in section ; but there is no conclusive
evidence of the cause of the external form.

Dr. Woopwarp referred to the interesting fact that the new
Cycadeoidea gigantea came from a higher level than the old historical
Dirt-bed described by Dr. Buckland. It is interesting as suggesting
the persistence for a long period of land-conditions—a point of great
interest to geologists. He bore testimony to the beauty of the
photographs shown by the Author.

Mr. Wurraxer also spoke.

The AvrHor expressed his thanks to the Fellows of the Society for
the reception accorded to his paper. He did not wish to give too
great prominence to the negative evidence as regards the position of
the inflorescence, and admitted the possibility that the small bud
found on the stem might bean aborted fertile shoot. He mentioned
instances of branching Cycadean stems in the tropical house at Kew.
‘There was no evidence, he believed, of the occurrence of Bennettites
in English rocks in an erect position with an elliptical stem, and
therefore he did not feel disposed to attach much importance to the
shape of the stem as a generic character. In conclusion, the Author
referred to his indebtedness to Mr. Gepp, of the British Museum, for
the excellent photographs taken of the Portland fossil.

AO MR. T.-L. WALKER ON THE [Feb. 1897,

4, GrotoetcaL and PrrroGRaPHIcaL Stupies of the SupBpury NIcKEL
District (Canapa). By T. L. Watxzr, Esq., M.A. (Com-
municated by J. J. H. Tart, Esq., M.A., F.R.S., Sec. G.S.
Read November 4th, 1896.)

[ Abridged. ]
ConTENTS.
Page

TD, EMPLOGUECHION. iiocecccensmcces «css. sc Fibede ek Sa ee 40
Dire Gmeres=Hormeanow te. sek aideeoed ese ee ee 41
Phe Emronian” Rocks Wak: sfc tte. fee ass Siete eae 43
Vj +he: Nickelsbearingnocks:: .cbai\./hs seh 0eskeks gensase aa eee eee 46
Vi. OthermNneleliteroussAtrreas h..Wee. ook aus atiece ciccle eee eee ee 59
Vil. “The sVoummer!sG ramihes! oii .dese soa daeete a. dino ge cesar Ree 61
Vi Olivine-ditioase Dykes es. tec cccem otcadebamedcmaneeeee eee 62
AV TD. elrterabure’ Bo beige) ol ea Se 65
AVR apo eta: Aaeiae etstnciet ties. Sete diaek » Moab deaGdhAcla Biba abiaab Whi sonthaes seen 64

I, Inrropvuction.

Tur town of Sudbury is situated in Northern Ontario, 442 miles.
from Montreal on the transcontinental line of the Canadian Pacific
Railway. When this railway was constructed some eight or ten
years ago, the name Sudbury was given to a small station which
was afterwards selected for the eastern terminus of the branch
railway that follows the northern shore of Lake Huron and crosses.
the St. Mary River at Sault Ste. Marie. It is about 40 miles from
the north-eastern shore of Lake Huron.

Shortly after the construction of the railway, considerable deposits
of chalcopyrite were discovered in the neighbourhood, and an
American company was organized to workthem. ‘Thus it was that
Copper Cliff Mine was opened up for copper, although along with
the chalcopyrite large quantities of nickeliferous pyrrhotite occurred.
The pyrrhotite was considered worthless, as it was not known to
contain nickel till the mine had been in operation for some little
time, and sales had been made of the products. After the accidental
discovery of the value of the pyrrhotite as a nickel ore, there was
much ‘prospecting in the district for nickel-deposits. This con-
tinued till 1891, by which time scores of nickel-deposits had been
located. At that time the world’s annual consumption of metallic
nickel was not more than 1500 tons, and hence it was a more diffi-
cult task to dispose of nickel properties at remunerative prices than
it was to discover them. For this reason, prospecting for nickel
was abandoned in this region, though it is quite probable that,
should a demand for larger quantities of nickel arise, many more
deposits will yet be discovered.

The earliest geological descriptions of the country in the imme-
diate vicinity of Sudbury were published by Selwyn in 1884. In
1888 Bonney published an account of the Huronian rocks exposed.

Wolk. 53.) SUDBURY NICKEL DISTRICT (CANADA). AL

in the cuttings of the Canadian Pacific Railway in the neighbour-
hood of Sudbury. During the seasons of 1888, ’89, and ’90, Bell and
Barlow were appointed by the Canadian Geological Survey to explore
the district. A collection of rocks was sent by Bell to the late
G. H. Williams, whose petrographical studies were published along
with Bell’s report. During the summer of 1890 the late Baron von
Foullon, of the Austrian Geological Survey, spent a few weeks in
the district, and directed his attention particularly to the determi-
nation of the relative ages of the different rocks. A full statement
of the literature bearing on the subject is appended (§ VIII. p. 65).
I beg to acknowledge my indebtedness to the writings of all who
have studied the geology of the Sudbury district, especially to the
papers of Adams, Bell, Barlow, Bonney, von Foullon, Garnier, and
G. H. Williams. Vogt’s excellent descriptions of the Norwegian
nickel-deposits and associated rocks have been freely consulted, as
in many respects these descriptions are quite accurate when applied
to the Sudbury district.

The nickel district is included in the great belt of Huronian rocks
which extends from the northern shore “of Lake Huron north-east-
ward to Lake Mistassini. In the neighbourhood of Sudbury this
belt is barely 25 miles wide, and consists of quartzite, amphibolite,
mica-schist, phyllite, voleanic breccia, and grauwacke. JInliers of
later eruptives form a large part of the belt, and it is in connexion
with one class of these that the nickel-deposits occur. The country
north-west and south-east of the belt of Huronian rocks is com-
posed of coarse granites and gneisses which are regarded as of
Laurentian age.

The whole of this part of Canada has been subjected to glacial
action, the general direction of ice-movement having been from
north-east to south-west. The rocks in many places present well-
polished surfaces, particularly where the protecting covering of
clay, sand, or gravel has been only recently removed, as in railway-
cuttings and along lake- and river-banks. The most lasting work
of glacial agency is seen in the hollowing-out of innumerable
depressions, which are now occupied by lakes and rivers, Archwan
districts in Canada are characterized by innumerable rocky lakes
with clear waters and swift eddying streams.

Il. Tue Gnetss-FormMaAtTion.

The larger part of Northern Ontario is occupied by gneisses of
various kinds. In the immediate vicinity of Sudbury these rocks
are not observed, though they form almost endless tracts on both
sides of the Huronian belt. Good exposures, which are easily
reached, occur in the cuttings of the Canadian Pacific Railway, near
Wahnapitae to the south-east, and about 3 miles west of Onaping
to the north-west. Besides these gneisses, which may be regarded
as Laurentian, there are gneissoid rocks geographically included in
the Huronian belt, but as these are of very much later origin, and
not true gneisses, it is proposed to deal with them in a later section.

49 , MR. T. L, WALKER ON THE [Feb. 1897,

(1) The Gneisses near Wahnapitae Station.

These rocks are well bedded, and show considerable folding on
a large scale. LBiotite is by far the most prominent constituent.
‘Over large areas reddish almandine-garnet is so common that the
Wahnapitae rocks may be designated ‘ garnetiferous biotite-gneiss.’
The garnets vary from § to 14 inch in diameter, and are often
so abundant as to constitute 20 per cent. of the rock. When in
micaceous bands they are crystallized in rhombic dodecahedra o O,
while when in quartzose or felspathic bands they are always
icositetrahedra 20 2. As a rule, garnets are inclined to crystallize
in rhombic dodecahedra when in schistose or basic bands, while
when in acid or granular bands there is a tendency to take the
form of icositetrahedra.

The microscope shows that the biotite is strongly pleochroic and
mearly uniaxial. It occurs as comparatively large independent
individuals, and never forms continuous films composed of innu-
merable small individuals. The biotite is sometimes altered to
chlorite. Muscovite is occasional. The quartzes abound in liquid
inclusions, which are often characterized by moving bubbles or
small cube-like crystals. Felspar plays an important part, and is
frequently perthitic or microclinic. Kyanite is often abundant, and
presents in rock-sections long, highly-polarizing individuals which
generally, but not always, conform to the schistosity. Inclusions of
quartz and felspar are quite common. The colour is different in
different individuals, and even in different parts of the same indi-
vidual. Some are water-clear, while others are water-clear with
irregular sky-blue flecks. No twinning could be detected. Silli-
manite is frequent on slickensides. The long, colourless, acicular
erystals show the effect of pressure in being broken into large
numbers of short prismatic fragments which are drawn apart, so
that the disjointed crystal is about twice as long as the original
crystal. Zircon in rounded grains is frequent, and seems to be
largely confined to the neighbourhood of biotite. When the zircon-
grains are included in the biotite, they are usually surrounded by
pleochroic areas (‘ pleochroitische Hofe ’}. i

(11) Gneiss near Onaping Station.

The gneiss exposed west of Onaping Station is largely composed
of quartz and felspar, which form pinkish-white bands: these
alternate with comparatively small bands of biotite. The Onaping
gneiss is thus very much lighter in colour than the gneiss at
Wahnapitae. The microscope shows that these rocks are true
gneisses and not crushed granites. Biotite occurs in large indi-
viduals, whose prismatic sections show a well-developed system of
partings which form a cross-hatching, probably the result of
pressure. The gliding-plane is apparently a pyramidal face, as has
been proved to be the case for large mica-individuals by Tschermak.
Biotite is sometimes changed to an aggregate of chlorite, epidote,

Wal. 5. ] SUDBURY NICKEL DISTRICT (CANADA). 43

and sphene. Specimens collected farther south-west on the same
gneiss-terrane contain almost equal quantities of biotite and mus-
covite, both of which are well preserved.

. JIT. Tae Hvuronran Rocks.

These are chiefly confined to the Huronian belt, which in the
neighbourhood of Sudbury is about 25 miles wide. Inliers of
different kinds are numerous, but these will be described in a later
section. Quartzite, grauwacke, mica-schist, phyllite, and altered
volcanic breccia are the chief constituents of the Huronian complex.
They have all suffered extensive metamorphism, so that it is
generally difficult to speak definitely as to their origin. Those
which have been derived by the disintegration of still older rocks
are to be regarded as among the oldest-known sediments. It is
possible that some of the above rocks have been derived from acid
tuffs, which in some cases may have been deposited in the primeval
sea, as suggested by the frequently perfect stratification. Some may
have been derived by the devitrification of flows of glassy, occa-
sionally porphyritic eruptives. Metamorphism has advanced so far
that the early history of these rocks is only very imperfectly
revealed. All of the above-mentioned sources have doubtless con-
tributed to the formation of the Huronian strata of the Sudbury
district.

(i) Quartzites.

In the immediate vicinity of Sudbury, numerous exposures of
these rocks are observed. In general the texture is very fine, the
stratification obscure, and the colour ashen-grey. The microscope
shows that the quartz-grains interlock as if much secondary
enlargement had taken place, although no outline of original grains
could be detected. Grains of perthitic felspar and scales of mus-
covite are mingled sparingly with the grains of quartz. Small
clusters of brown mica and rounded spots of chlorite are often seen
in thin sections. The general strike is N. 30°E. A short distance
north of Sudbury, on the way to Blezard Mine, an evenly-stratified
quartzitic rock occurs. Narrow bands of a few millimetres in width
may be often followed for some score yards. A microscopic exami-
nation shows the presence of much muscovite and numerous small
colonies of chlorite. This rock is also well exposed along the road
to Copper Cliff Mine, about a mile from Sudbury. West of Sudbury,
along the Canadian Pacific Railway, the quartzites are, as a rule,
very thickly bedded, while in some cases bedding is scarcely dis-
cernible.

South-east of Sudbury, along the rocky shores of Ramsay Lake,
conglomeratic phases of the above quartzites occur. The pebbles
are in the main of reddish granite and vary much insize. Asa
rule, the south-eastern side of the Huronian belt is composed of
the quartzitic rocks just described. The conglomeratic portions
are undoubtedly derived from still older Archzan rocks, while the

44 _ MR.T.L., WALKER ON THE * [Feb. 1897,

evenly-bedded, very micaceous strata may represent altered acid
tuffs which were deposited in shallow water. Bonney has suggested
that some of the very fine-grained, indistinctly-bedded muscovite-
quartzites may have been derived by devitrification of acid glassy or
porphyritic rocks.

Exposures of highly-altered quartzite occur south of the Stobie
Mine, and also on the main line of the Canadian Pacific Railway,
11 mile west of Sudbury. At the former place, the altered rock
becomes quite granitic in composition, and gneissoid in structure.
The microscope shows that the component minerals are quartz,
felspar, biotite, and a little muscovite. Quartz-grains abound in
fluid inclusions, are irregular in ontline, and generally interlock.
Muscovite forms large separate individuals, while biotite usually
forms approximately-parallel connected aggregates of small scales,
The rock exposed on the railway west of Sudbury is of medium
grain and peculiarly mottled: pale pink, roundish spots, from 1 to
4 inches in diameter, dapple a groundwork of a dark grey colour.
On closer examination, it is seen that no sharp boundaries exist
between the portions of different colour, and a microscopic exami-
nation shows that there is no important mineralogical difference.
Gneissoid structure is altogether wanting. Crystals and grains of
reddish garnet occur in addition to the minerals present in the
rock south of Stobie Mine. Cousidering the mineralogical compo-
sition of these rocks, they may be referred to as biotite-granite.
Bell has shown that these highly-altered clastics constitute a belt
4 mile wide and 6 miles long, extending from near the Stobie
Mine south-west nearly to Copper Cliff Mines. Naturally, only a
very impure quartzite could give rise to such rocks as these. We
know very little as to the causes of this extreme and apparently
selective metamorphism. Rocks of granitic composition and struc-
ture, when formed by the regeneration of clastics, may be called
‘regenerated granites.’ There is reason to believe that this is a
more fruitful source of granitoid rocks than has been previously
acknowledged.

(11) Mica-Schists.

In the immediate vicinity of Sudbury these rocks, though occa~
sionally present, play a very subordinate part. They generally dip
at high angles, and are more frequent towards the centre of the
Huronian belt. A very narrow band of silvery grey mica-schist
crosses the railway about 4 mile east of Murray Mines. In thin
sections the foliation is very distinct. Muscovite forms a net-
work which surrounds the quartz-grains. Immediately east of
Worthington Station a similar rock is exposed in the railway-
cuttings. Farther south-west the Huronian belt is much richer
in mica-schists,. which are often hornblendic and _ staurolitic.
Between Blezard and Stobie Mines a dark, compact, schistose rock
occurs, which the microscope shows to be a hornblende-epidote-
schist ; it is perhaps geologically an equivalent of the mica-schists.

Nok 53:] SUDBURY NICKEL DISTRICT (CANADA), 45

(iii) Phyllite.

This rock is very closely associated with the mica-schists, and
may be examined in the railway-cuttings 3 miles east of Worth-
ington Station. The rock dips at high angles, and is purple-brown
in colour. On the cleavage-surfaces small yellowish-brown specks
are observed which the microscope shows to be sagenitic aggregates
of rutile-crystals: these are fairly transparent, and so large as to
give polarization-colours resembling those of zircon.

(iv) Clay-Slates.

These constitute an important member of the Huronian complex.
They may be examined 3 mile west of Rayside Station, and also a
short distance north of White Water Lake. In the former place
they are in contact with the nickel-bearing rocks, and close to the
junction the schistosity has quite disappeared. They are ashen-
grey, drab to nearly black in colour, and probably represent detritus
deposited in the deeper seas of the Huronian period.

(v) Volcanic Breccia.

The western portion of the Huronian belt in the Sudbury district
is occupied by a trough which is composed of the younger Huronian -
rocks. This trough extends nearly from Lake Wahnapitae south-
westward to the township of Trill, a distance of over 30 miles.
The greatest width is a little over 8 miles. The central part of the
trough is occupied by evenly-grained grauwacke, while the margin
is composed of a highly-altered volcanic breccia. One of the most
accessible exposures of this breccia is on the northern shore of
Whitson Lake, where it is in contact with the nickel-bearing
eruptive. The colour is ashen-grey, the stratification distinct,
though interrupted and lumpy, and the strike is N. 70° E. The
microscope discloses the breccia-structure. The volcanic fragments
are quite angular, and sometimes show flow-structure, though they
have been generally replaced by aggregates of secondary minerals
—chlorite, quartz, felspar, muscovite, and calcite. Glass could be
seen neither in the fragments nor in the matrix. An analysis of
the breccia north of Whitson Lake gave the following results :—

Sis er caete- ere 59°93 °/,
al, Oy Gt cose on ee ee
BAO vss 25.42 Gaile 1056: ,,
VEO ec seep taterays «5 trace
MONEY eh he ten ap hs 4:49 ,,
BLO aged. deren see Ae
12s Aare rsa aued ooo" |,
NOE Heth d. ctv arden OT 55
Loss by ignition... 1°57 ,,
MOG aily os fie dies chee 98°63

There are also good exposures of this rock along the north-western
border, about 13 mile south-east of Onaping Station.

46 “MR. T. L. WALKER ON THE [Feb. 1897,

(vi) Grauwacke.

The central portion of the trough of younger Huronian rocks is:
occupied by an even-grained, ash-coloured, quartzose rock, in which
conglomeratic fragments may be detected with the naked eye.
This is the youngest member of the Huronian complex, and, as it is
never cut by the nickel-bearing rocks, I am inclined to regard it as
later than these. There is good ground for looking upon the nickel-
bearing rocks as younger than the volcanic breccia, and hence the
conclusion that the nickel-bearing rocks are of Huronian age, and that
they occupy a position lying chronologically between the volcanic
breccia and this youngest member. It may be mentioned, however,
that Bell and Selwyn are inclined to regard the grauwacke as Lower
Cambrian, although no fossils have been found in it.

Good exposures occur at several points along the railway,
especially at Chelmsford and Larchwood Stations.

LV. Tur Nickrt-BEARING Rocks.

(i) General Observations.

These rocks have attracted much more attention than the other
rocks of the district. The discovery of areas characterized by
extensive deposits of nickel ores gave employment to large numbers:
of explorers from 1887 to 1891. It was soon remarked that
valuable deposits of copper and nickel ores. occurred only in con-
nexion with greenish-coloured rocks of medium texture, which
were conveniently referred to as trap, diorite, or greenstone.
Early microscopic examination of the rocks in the immediate
vicinity of the nickel-deposits showed that they were composed in
general of hornblende and plagioclase, and in smaller proportions.
of quartz and biotite, with magnetite and apatite as accessories.
Thus the microscope confirmed in a measure the prospectors’ name
‘diorite, but it also showed the probability of the secondary nature
of the chief constituents, and so the original nature of the: —
country-rock of the nickel-deposits continued to be a matter of.
doubt. As the hornblende was probably derived from one of the
members of the pyroxene group, the original rock was doubtless one:
of the gabbro family.

In the published descriptions these rocks are referred to as diorite,.
uralitic diorite, gabbro-diorite, and even occasionally as diabase.
This uncertainty is in a measure accounted for by the fact that.
most of the specimens studied microscopically were collected quite
close to the nickel-deposits, where the rock is as a rule completely
altered, though in other parts of the ‘greenstone’ area the meta-
morphism has seldom advanced so far, and in some places the rock
is practically unaltered. .

It will be seen that the nickel-bearing rocks, taken as a whole
and considered geologically, include not only these greenstone areas
but also considerable areas of gneissoid and microp egmatiti

Wolk. 53.) SUDBURY NICKEL DISTRICT (CANADA). . 47

granite, which cannot be genetically separated from the green-
stones. The geological map of the Sudbury district published by
the Canadian Geological Survey contains nearly one hundred areas
of greenstone. We will confine our attention to a very small
number of these nickeliferous eruptives.

The nickeliferous rocks are included in or adjoining the Huronian
belt already described. They commonly form long elliptical areas
whose longer axis is more or less parallel to the stratification of the
Huronian rocks. The largest of these areas extends from the town-
ship of Garson south-westward into the township of Creighton,
having a width of nearly 4 and a length of at least 25 miles. It
is crossed by the Canadian Pacific Railway between Murray and.
Rayside Stations. The area second in size is described by Bell as
extending from the township of Lavack south-westward to the
township of Trill. Its length is at least 18 miles, and its width
between 3and 4 miles. Onaping Station is situated near the south-
eastern border of this eruptive area. As the former eruptive is well
exposed in the vicinity of Whitson Lake, it will be convenient to
refer to it as the Whitson Lake eruptive. For a similar reason,
the second eruptive area will be referred to as the Windy Lake.
eruptive.

(ii) The Whitson Lake Eruptive.

The length of this area has been very moderately stated above ;
there is good reason for regarding it as much greater, and possibly
connected with other nickeliferous areas which are now mapped as
separate eruptives. The best exposures are to be found along the
shores of the lakes lying within its bounds, and in the cuttings
of the Canadian Pacific Railway. Along its north-western boundary
itis flanked by the volcanic breccia previously described. It includes
three parallel areas, which were mapped by Bell as greenstone,
granite, and Huronian. It will be shown that the rocks which
constitute these three terranes, though so different in appearance,
are genetically a unit, that they are eruptive and younger than the:
enclosing rocks, and that in their apparent diversity they may
rightly be referred to as nickel-bearing rocks.

a. Haposures along the main line of the Canadian
Pacific Railway.

This eruptive is well exposed in the railway-cutting between
Murray and Rayside Stations. Its width here is about 4 miles. As
the rock is freshest towards the centre of the area, it will be ad-
visable to consider in detail specimens collected there ; then to study
in order the specimens collected between the fresh central or type-
rock and the Murray Mines contact, and finally the specimens from.
the north-western half, beginning at the centre, and proceeding
towards the north-western contact near Rayside Station.

The Type-rock.—About 14 mile north-west of Murray Mines,

A8 MR. T. L. WALKER ON THE © [| Feb. 1897,

near the point where the railway enters the township of Rayside,
there are good exposures of a somewhat coarse-grained rock, which
is greenish on the weathered surface, while the freshly-broken
surfaces exposed in the railway-cuttings are nearly black, with a
bluish tint. It is the diorite or greenstone of the prospectors,
which the microscope shows to be norite. Hypersthene forms
idiomorphic crystals, and seems to have been the first of the essential
minerals to crystallize. Sections of this mineral when in the pris-
matic zone are stoutly rectangular, while sections parallel to the
basis are octagonal and show indistinct prismatic cleavage. It is
strongly pleochroic—rose-red, bluish-grey to nearly colourless. The
crystals of hypersthene are generally bordered and veined with
bastite, which often contains small grains of magnetite. In other
cases the alteration has proceeded so far that one observes rect-
angular areas of bastite which contain only a few separated grains
of hypersthene. Where the bastitic alteration-products border on
plagioclase, a still further change occurs, in that bastitic fibres and
magnetite-grains give place to a somewhat compact, strongly
pleochroic, bluish-green hornblende. This latter change does not
occur along borders between bastitic areas and biotite or magnetite.
The felspar seems to participate, by contributing the alumina
necessary for the formation of green hornblende.

Plagioclase is the most abundant mineral. The crystals are
xenomorphic when in contact with hypersthene, which is thus seen
to have crystallized earlier than the plagioclase. The broadly-
twinned plagioclase-crystals are from two to three times as long as
broad, and even in the thinnest sections are brownish, owing to the
presence of innumerable dust-like inclusions, which are regarded as
ilmenite, and are very characteristic of plagioclase in norites.
Besides these brown inclusions, too small to admit of microscopic
determination, there are colourless needle-like inclusions which form
a network of three parallel systems. It is probable that these in-
clusions are parallel to the three edges formed by the pinacoidal
faces. Measurements of extinction-angles lead to the conclusion
that we are here dealing with bytownite.

Augite forms occasional, large, irregularly-bounded grains, which
are non-pleochroic, and xenomorphic with respect to hypersthene
and plagioclase. Inclusions parallel to OP give the appearance
of basal cleavage when examined with a low power.

Besides the above-mentioned hornblende, which is of secondary
origin, there is a small proportion of apparently primary nature.
It never occurs alone in well-formed crystals, but mostly forms
borders on crystals of hypersthene and on areas of bastite derived
from these. This hornblende possesses well-developed cleavage,
definite outline when bordering on felspar, is darker than the
secondary hornblende, and is compact and not fibrous. Much
might be said in favour of the secondary nature of this hornblende,
where it could be regarded as the final product of the alteration
represented by the change of hypersthene to a bastite-magnetite
aggregate, this to bluish-green hornblende with no characteristic

Vol. 53-] SUDBURY NICKEL DISTRICT (CANADA). 49

outline or cleavage, and finally the hornblende in question with
definite outline, strong pleochroism, and characteristic cleavage.
Were this the case we should expect to find the largest amounts of
this hornblende in rocks where alteration had advanced farthest.
This, however, as will be seen later, is not the case, and hence it is
preferable to regard this well-developed hornblende as primary, and
as having formed borders on the pyroxene-crystals in the original
unaltered norite. When so regarded, we find difficulty neither in
explaining its presence as a border on perfectly fresh hypersthene-
erystals, nor in its surrounding the bluish-green hornblende, which
is undoubtedly of secondary nature.

Biotite is occasionally observed in well-developed scales, of whose
primary nature there is no doubt. Secondary hornblende forms
a very narrow border on biotite-scales when in contact with
plagioclase.

Apatite, magnetite, and occasionally grains of iron sulphides are
present, as is usually the case in such rocks. The very last
mineral to crystallize was quartz, which is represented by a few
irregular grains.

From this description it will be seen that the type-rock of the
nickel-bearing eruptive exposed between Murray and Rayside
Stations is a norite containing small quantities of biotite, hornblende,
and augite. The slight alteration in no way obscures the original
nature of the rock.

East of the Type-rock.—Eastward along the railway very little
change is observed in the character of the greenstone for some
distance. About 1 mile east of the type-rock two intrusions of
granite occur. The broader of these has a width of about 100
yards. The later age of this granite may be concluded, as it sends
apophyses into the norite, and where in contact with the latter
rock it has changed the pyroxenes to hornblende and biotite.
Similar action may be observed on fragments of norite included in
the granite. This intrusive granite will be fully described later.
It is enough here to know that we have sufficient ground for
regarding the norite as a continuous area.

About 3 mile east of the type-rock the rock is macroscopically
unchanged, except that it peels off in concentric layers when exposed
to the weather, as is frequently the case with diabase, but not with
norite. ‘The microscope shows that it is more altered than the
type-rock. Most of the hypersthene-crystals are so altered that
generally only a few isolated grains can be detected in areas of
secondary hornblende, whose areas are identical with those of the
normal hypersthene-crystals. The secondary hornblende is the
Same as in the previous rock, except that there is relatively more
pale bluish-green hornblende and less bastite.

A few needles of secondary pale-green hornblende occur in the
plagioclase, as ii the bastite-substance had been transported into
the felspar, aud had there produced the pale green hornblende,
which in the type-rock occurred only where bastite bordered on
felspar. The plagioclase constitutes two-thirds of the rock, and,

Q.J.G.8. No. 209. E

50 ' MR. T. L. WALKER ON THE [Feb. 1897,

except for the presence of hornblende-inclusions, does not differ from
that of the type-rock.

Passing eastward, the rock becomes slightly finer-grained, but
does not differ materially from the type-rock. About 200 yards
from the smelting-works at Murray Mines, the rock when examined
microscopically is seen to differ from the former specimens in two
ways: there are differences on the one hand which are due to
metamorphism, and these may be regarded as of secondary nature ;
and on the other hand there are differences of a primary nature,
and these are to be explained as due to the differentiation of the
original rock-magma. Neither crystals of hypersthene nor even pre~
served remnants of the mineral, such as were noticed in the previous
rocks, can be observed, and we are able to prove its presence in the
original rock only by reference to the areas of bastite and secondary
hornblende. The more or less regularly rectangular areas have
been derived from hypersthene, while quite irregular areas have
been probably derived from augite. Primary hornblende is not so
abundant as previously, while biotite, which appears to be of
primary nature, is more abundant. Plagioclase is characterized by
brown dust-like inclusions, and by small colourless crystals which
are probably zoisite or epidote.

The plagioclase-crystals contain numerous particles of secondary
ereen hornblende, which is at times so plentiful as to somewhat
conceal the original felspar-boundaries. The same indistinctness is
often observed in connexion with the secondary products resulting
from hypersthene and augite. SBastite-substance seems to have
been transported in solution from the original hypersthene-areas,
and to have produced the secondary hornblende in the plagioclase
by reacting upon it. Generally the solution followed cleavage-
planes in the felspar, but frequently the cleavage-paths cannot be
traced. This process, whereby secondary hornblende is formed by
the action upon plagioclase of solutions carrying bastite-substance,
and the deposition of the hornblende distant from the bastite-areas,
may be referred to as the ‘ migration of hornblende,’ and hornblende
so formed may be called ‘immigrated hornblende.’

Between the smelting-works and the Murray Mines ore-deposits —
the rock is finer-grained and more altered. The microscope shows
that the secondary hornblende is nearly all of the bluish-green type,
bastite having almost disappeared. The migration of hornblende
has become much more general, so that the old boundaries of the
pisilicates are very imperfectly preserved in the areas of their
secondary products. Itis also worthy of note that a few of the
areas of secondary hornblende seem to have suffered a still further
change, and to have given rise to dark brown, fine, scaly biotite.
This seems to be the final product of the alteration which changes
hypersthene successively to bastite-magnetite aggregate, pleochroic
bluish-green hornblende, and finally scaly biotite. The production
of biotite from secondary hornblende seems to have been much
more frequent in the small individuals included in the felspar. The
plagioclase swarms with epidote-crystals and shows very irregular

Vol. 53.] SUDBURY NICKEL DISTRICT (CANADA). 51

boundaries. Grains of chalcopyrite and pyrrhotite are very
frequent.

In the railway-cutting quite close to the Murray Mines deposit,
which is very near the south-eastern border of the Whitson Lake
eruptive, the rock contains a large amount of pyrrhotite and chalco-
pyrite. It has been much more altered than the rocks already
described. Hypersthene and augite have entirely disappeared and
have been replaced by green hornblende, which does not appear to
be confined to any definite areas. Primary plagioclase cannot be
detected, but seems to have given place to small individuals which
are broadly twinned and water-clear. A few scales of biotite, a
little primary hornblende, numerous small irregular grains of quartz,
and swarms of pyrrhotite- and chalcopyrite-grains, complete the
list of constituents. The rock has been almost entirely recrystal-
lized, and its original nature is somewhat concealed. In composition
it corresponds at present to an uralitic diorite, and has doubtless
been derived from a rock of the gabbro family. For convenience,
these altered norites or gabbros will be referred to in the following
pages as ‘ greenstones.’

Although the rocks collected along the railway near Murray
Mines indicate a total disappearance of hypersthene and a large
‘increase of secondary hornblende, yet there is good ground for
regarding these rocks as having been derived from norite. The
late Baron von Foullon described a rock which was blasted out
when the foundations were being prepared for the smelting-works
at Murray Mines, not more than 100 yards from the contact.
This rock is described as containing strongly pleochroic semi-
‘idiomorphic hypersthene-crystals, along with a smaller amount of
diallage. He observes that these minerals are often bordered with
hornblende. The rock on the dump at Murray Mines is generally
fine-grained and too much altered to‘show hypersthene, but in the
lower workings, 10 to 20 yards removed from the contact, the ore
occurs in a rock of medium grain, which contains an abundance of
fresh hypersthene. This rock shows a large amount of diallage-like
-augite and secondary hornblende, while plagioclase is not so abundant
as usual, and has been partly recrystallized.

The contact with the granite on the south-eastern side of the
eruptive is not very sharp. Granite is mingled with greenstone for
100 to 150 yards and often forms breccias with it. The breccias
have a granitic grained matrix, and sharply angular greenstone-
fragments which vary much in size. The granite is very fine-grained
near the contact, and is certainly younger than the greenstone.
It seems to have been intruded along the wall between the green-
stone and the original clastic, which was in contact with the
eruptive greenstone before the intrusion of the granite. A narrow
band of this clastic may now be seen along the railway about 4 mile
east of the present contact of the Whitson Lake eruptive with the
granite. .

The nickeliferous pyrrhotite is intimately intermingled with
the greenstone. Chalcopyrite is present in very much smaller

E 2

59 MR. T. L, WALKER ON THE [Feb. 1897,

quantity. The pyrrhotite often contains crystals of magnetite and
biotite, which are consequently older than the pyrrhotite con-
taining them. By examining some specimens one might conclude
that the ores had crystallized before the silicates, while an exami-
nation of other specimens would lead to the opposite conclusion.
The ores are, in fact, to be regarded as constituents of the rock,
which at a few places along the border of the eruptive have been
concentrated by differentiation, so that the ore-deposits are norite or
greenstone, which is rich enough in chalcopyrite and nickeliferous
pyrrhotite to be of commercial value. The quantity of the ores in
the rock increases gradually towards the border, till it often consti-
tutes three-fourths of the rock. Sometimes the ores and silicates:
are finely intermingled, while at other times comparatively pure
masses of pyrrhotite and chalcopyrite are included in the silicate—
groundmass. These masses of pure ore vary from a few lines
to a foot in longest diameter. In other cases the ores appear to
form the groundmass in which the silicates are included. Near the
contact the grain of the ores is fine, and the proportion of chaleo-
pyrite and pyrrhotite is often so large as to form deposits of economic
importance, while farther from the contact the ore becomes coarser-
grained and the quantity of silicates increases till it can no longer
be worked at a profit. The nickel percentage of the pyrrhotite
varies greatly, but may be safely stated as ranging from 3 to 7 for
the deposits which have been worked on a large scale. There
are, however, many deposits which contain less than 3 per cent. of
nickel, but these are at present of no special value.

Vogt, in describing similar nickel-deposits in Norway, regards the
pyrrhotite and chalcopyrite as rock-forming minerals, and believes
that they took their present form at the time of the solidification
of the rock containing them. JHe refers to the rock rich in
pyrrhotite as ‘ pyrrhotite-norite,’ and observes that the ores generally
diminish with the distance from the contact. He regards the ores-
as the most basic rock-constituents, and considers that the pyrrhotite-
norite is related to the greenstone in the same way as basic borders.
on granite-stocks ere to the granite. Both, he maintains, have been:
formed by differentiation of once homogeneous magmas. My obser-—
vations lead me to think that the same relations obtain in the case
of the Sudbury chalcopyrite-pyrrhotite deposits.

Occasionally small masses of titaniferous magnetite are associated
with the pyrrhotite. An analysis of such a mass from Murray
Mines showed the presence of 18°34 per cent. of titanic acid. At
other points along the border of the Whitson Lake eruptive similar
masses of titaniferous magnetite occur. Portions of norite which
are rich in titaniferous magnetite might well be so named as to:
indicate the presence of magnetite as an essential mineral. Similar
peripheral separations of titaniferous magnetite are frequent in
connexion with the gabbros of Minnesota, as Bayly has recently
pointed out.

About 100 yards south of the office at Murray Mines a
porphyritic facies of the greenstone occurs. The groundmass is:

Vol. 53.] SUDBURY NICKEL DISTRICT (CANADA). 53

fine-grained and weathers to a greenish colour. Crystals of black
hornblende, varying in size from peas to ‘marbles, are richly
scattered through it.

Rocks West of the Type-rock.—We shall now examine in turn
the rocks collected along the railway between the type-rock and
‘the north-western contact.

About z mile north-west of the type-rock, there seems to be
little change macroscopically. Small sapphire-blue grains of quartz
are frequently observed in the dark rock. The microscope shows
the complete alteration of hypersthene to bastite and green horn-
blende. The boundaries of the secondary products are fairly sharp,
although there has been considerable migration of bornblende.
Frequently the secondary hornblende is associated with scales of
biotite, asif the latter had been produced from the former. Within
the bounds of the old hypersthene-areas the hornblende extinguishes
in two portions, and presents in some cases, between crossed nicols,
the appearance of polysynthetic twinning on the orthopinacoid.
There are occasional irregular areas of secondary hornblende, as if
derived from augite. Primary hornblende and biotite are present
in about the same proportions as in the type-specimen. Micro-
pegmatite forms a few small areas, and seems to have been one of
the last constituents to crystallize.

One mile east of Rayside Station the mee becomes quite coarse
and gabbro-like. The dark minerals constitute only a third of the
rock. Microscopically it differs from the last specimen in the total
disappearance of the bastite stage of secondary hornblende, an in-
«rease in fine scaly biotite in association with immigrated hornblende,
and an abundance of epidote-crystals in the plagioclases. The
original rock was of a somewhat more acid character than those
previously examined, as indicated by an increase in the quantity of
quartz and micropegmatite. There are a few grains of a mineral
which is strongly pleochroic—purple, rose, colourless—and which is
generally associated with the bisilicates. It is probably orthite.

Westward the rock takes on gradually the appearance of a granite.
The weathered surface is white to pink instead of green, while an
indistinct parallelism is sometimes noticeable. Fine scaly biotite is
more prominent, while the large, bright, black cleavage-surfaces of
hypersthene, biotite, and hornblende are seldom observed.

A specimen collected about + mile west of Rayside Station repre-
sents the north-western border of the area. The weathered surface
is pale pink. Parallelism in the constituents is very apparent, so
that the structure is coarsely gneissoid. The texture is finer than
in the central portion of the eruptive. The microscope shows that
fine scaly biotite is the only bisilicate present, that orthoclase is
much more abundant than plagioclase, and that quartz in small
grains makes up about half the rock. This granitic rock has been
subjected to considerable pressure, as indicated by the undulatory
extinction of the quartz-grains and the bending and breaking of the
plagioclase-crystals.

Quite at the contact, in a hill 3 mile north-west of Rayside

54 MR. T. L, WALKER ON THE [Feb. 1897,.

Station, the slate has been so altered by the eruptive as to lose its
schistosity and to resemble the ‘ hornfels’ so commonly produced by
granite when in contact with slate. This rock is shown by the
microscope to be composed of fine scales of biotite and muscovite and
grains of quartz. The quartz-grains are bounded by polyhedral
outlines, so as to produce the ‘ pavement ’-structure which is so:
characteristic for contact-products. Roundish mica-scales are:
frequently included in the quartz-grains. These microscopic struc-
tures confirm the contact nature of the rock. Calcite-grains are so
common that the rock-powder effervesces briskly with cold hydro-
chloric acid.

There are numerous inclusions of quartzose fragments in the
eruptive near the junction. The presence of these quartzite-inclusions
in the eruptive indicates that it has broken through quartzitic strata,
which consequently underlie the slates at present observed in contact.
with the granite.

3. Exposures north of Blezard Mine.

The south-eastern contact is only a short distance south of
Blezard Mine. The rocks are well exposed along the road north
of the mine, while excellent opportunity is afforded for geological.
examination by the rocky shores and islands of Whitson Lake. The
rocks of this cross-section of the Whitson Lake eruptive are quite
similar to those studied in the previous one along the main line of
the Canadian Pacific Railway.

The rock a short distance north of the mine is almost identical
with the type-rock of the last series. It is dark, and of medium
texture. The freshly-broken surface shows a few scales of biotite.

Specimens collected 200 yards south-west of the mine along the
railway show that the rock has undergone considerable alteration.
The original bisilicates and plagioclase have been replaced by
secondary hornblende and irregular water-clear grains of plagioclase,
which are generally accompanied by small grains of quartz.

Northward from Blezard Mine the rocks show an increase in
acidity and alteration. By canoe one may visit the shores and.
islands of Whitson Lake, where further changes are observed. On
an island about 4 mile south of the narrows the rock begins to
show a granitic appearance, the quantity of quartz is much larger,
brown scaly biotite and a little secondary hornblende represent the
bisilicates, while untwinned orthoclase-felspar is present in about
equal quantity with the narrowly-twinned plagioclase.

Areas of secondary hornblende generally extinguish more or less
distinctly in two portions, but in sections of the above rock this.
manner of extinction is very plain. Moreover, in some cases horn-
blende twinned polysynthetically on oo P w is connected with these:
areas, and one part of the hornblende-mosaic extinguishes with one
series of twinning-lamelle, while the other part of the mosaic
extinguishes with the alternate series of twinning-lamelle. This.
proves that the hornblende of the mosaic is oriented in the position.
for twinning on o Po. It differs, however, from the ordinary:

Vol. 53.] SUDBURY NICKEL DISTRICT (CANADA). 55

twinning, in that there is complete interpenetration of the horn-
blende-individuals, which in the ordinary twinning are separated by
straight lines, as is the case with plagioclase when twinned poly-
synthetically. It has been long remarked that areas of secondary
hornblende extinguish in two portions, but the exact orientation of
the one portion with reference to the other has not been previously
determined.

Specimens from an island near the narrows of Whitson Lake
show distinct parallelism, and appear to be gneissoid granite. The
scaly biotite which occurred sparingly in the previous specimens is
here a prominent constituent, and forms continuous films of small
individuals, which give to the rock its parallel structure. Ortho-
clase is much more prominent than plagioclase, while micropeg-
matite constitutes nearly half the rock. It is interesting to note
that the felspar present in the micropegmatite is well-twinned
plagioclase.

Farther north the islands and shores present the same rock as
that just described, except that scaly biotite, quartz, and orthoclase
are almost the sole constituents. Micropegmatite nearly disappears
in the northernmost specimens. Sometimes the rock contains
numerous grains of calcite, which is well twinned and water-clear.
This mineral is certainly not a decomposition-product of the granite,
which is quite fresh. It may be a primary constituent, or more
probably an infiltration into the small cavities of the originally
somewhat porous rock. Similar calcite-granites have been reported
by Hawes from New Hampshire, and by Tornebohm from Guémilo
in Sweden.

The north-western contact occurs at the extreme north of the
lake, near the mouth of a small creek. The rock to the north-west
is the silicified breccia previously described.

This cross-section of the Whitson Lake eruptive shows that it
extends from a short distance south of Blezard Mine to the northern
end of the lake, a distance of 34 miles, and that there is a gradual
increase in acidity towards the north.

y. Exposures along the line between Lots 8 and 9 in the
Township of Snider.

A two days’ trip was made through the woods along the line
between lots 8 and 9 in the township of Snider, in order to study
further and map the Whitson Lake eruptive. It was found that on
the southern shore of the lake the rocks exposed were gneissoid
granites similar to those seen near the narrows of Whitson Lake.
The contact occurs about 4 mile north of the lake. Passing south-
ward towards Meat Bird Tee the granite gradually gave place to
the normal greenstone. The eauelnesd seule was found to be near
the boundary-line between concessions II. and III. Its width is
therefore about 4 miles.

Thus it is seen that this section of the Whitson Lake eruptive is
quite similar to the two sections already described.

56 _ MR, T. L. WALKER ON THE [Feb. 1897,

While engaged as an assistant on the Canadian Geological Survey
in 1890, and exploring south of White Water Lake with a view to
determining the boundaries of the eruptive, I first observed that
there was not a sharp boundary between the greenstone and the
granite lying north-west of it, since there appeared to be everywhere
a gradual transition from the one to the other.

In the previous pages it has been shown that such transitions
occur along all the cross-sections of the Whitson Lake eruptive. The
variations in chemical composition of these rocks are illustrated in the
following series of analyses of specimens collected along the Blezard
Mine crossing. The specimens range from south to north, from
I to V. I am indebted for analysis IV to Mr. C. B. Fox, M.A,
chemist of the Iron and Steel Company, of Hamilton, Ontario :—

I II avg, IV. V

7 Bi 0 | 0 oh 0 °/ 0
SIO) scaneaees 49:90 51°52 64°85 69°27 67°76
MIO os ccpaceaks 1°47 NaS" a es 0-78 0°46
lS 0 Bee ae A 017 0:10 0:24 0:06 0:19
AG ys Rts 16°32 19:77 11°44 12°56 14:00
MD... ates lc gieinieis ds “47 2°94 289). cee
EO) Vie aes 13°54 6°77 6:02 4°51 5:18
CAO uanene. 6°58 8:16 3°49 1:44 4:28
IWIBO) cc csetiee 6:22 6°49 1:60 0°91 1:00
1:1) a @ Waas At trace trace trace trace trace
BOS OE e. Seshd «> 2-25 0:70 3°02 3°05 1:19
INES © DON Seas 1°82 2°66 3°92 3°12 5:22
EERO. -8 oa: 0°76 1:68 0°78 (76 101

Motel.) cs 99:03 99°71 98°30 99°35 100-29
Specific gravity= 3-026 2°832 2°788 2724 2-709

Several of the most important nickel-deposits occur along the
south-eastern border of the Whitson Lake eruptive; among others
the Blezard, Murray, Little Stobie, and Lady M°Donald mines.

(iii) The Windy Lake Eruptive.

This eruptive is situated about 25 miles north-west of Sudbury,
and is known to extend from the township of Lavack south-west to
the township of Trill, a distance of 20 miles, though its total length
is probably much greater. Exceptional opportunity is afforded for
the examination of this eruptive by the cuttings of the Canadian
Pacific Railway near Windy Lake, where the rock extends over a
width of nearly 4 miles. Onaping Station is situated near the
south-eastern border of the area.

About 33 miles west of Onaping Station the railway passes
through a ridge of greyish to pinkish, heavily-bedded gneiss, which
was described at the beginning of this paper (p. 42). On travelling
eastward a few hundred feet along the low margins of Windy Lake
no rocks are observed, but a little farther east there are exposures
of a medium-grained rock, in which the unaided eye distinguishes
a black mineral occurring as separate grains, and a much more

Vol 53.) SUDBURY NICKEL DISTRICT (CANADA). 57

abundant white mineral forming the groundmass for the dark
mineral. Though a norite, this rock differs in appearance from the
Whitson Lake eruptive in being coarser-grained and of a much
lighter colour.

The microscope shows that here the hypersthene, though often
quite fresh, is more frequently changed partly or even entirely to
bastite or secondary hornblende. The plagioclase-crystals are quite
free from the dusty-brown inclusions observed in the plagioclase of the
Whitson Lake norite. This difference is largely responsible for the
comparatively light colour of the Windy Lake norite as contrasted
with the dark colour of the Whitson Lake norite.

A specimen collected 4 mile east differs from the last in being
Slightly more altered and of somewhat more acid character. Some
crystals of plagioclase exhibit in an unusual degree zonal structure
and wandering extinction. In some cases there is a difference of
38° between the extinction of the central and marginal portions of
the same individual. Such plagioclase-crystals generally border on
small areas of quartz and micropegmatite, and appear to have con-
tinued their growth till all the constituents except the quartz and
micropegmaitite had crystallized. ‘The central portion is therefore
composed of one of the most basic plagioclases, while the marginal
portion represents one of the most acid of the series.

Eastward the rock becomes coarser in grain, and the greyish
norite gives place to what might be taken macroscopically for a
hornblende-syenite. A specimen collected 27 miles west of Onaping
Station, when examined microscopically, shows that secondary horn-
blende is the only bisilicate present. Micropegmatite and quartz
are more abundant: the felspar of the micropegmatite is well-
+winned plagioclase. There are a few grains of a yellowish pleochroic
mineral, which has strong polarization-colours and a high index of
refraction. As this mineral becomes much more abundant near
Oueping Station, it will be more fully dealt with later: it seems to
alter to radiating aggregates of pale lemon-yellow hornblende.

Towards Onaping Station there is a marked increase in the
quantity of micropegmatite, which forms about half the rock. Well-
defined felspar-crystals form the centres for radiating micropeg-
matite areas. Taking into consideration the prominent part played
by micropegmatite and the porphyritic nature of the rock, it may be
called a ‘ hornblende-porphyry with a micropegmatitic groundmass.’

There is, moreover, another important constituent. This occurs
commonly in groups of irregular grains, and is distinctly pleochroic—
lemon, yellowish-green, and colourless. The index of refraction
is high, and the surface appears to be quite rough when seen
under the microscope. The double refraction is high, so that it
polarizes in orange-green and red tints when quartz of the same
thickness polarizes in grey. It is always associated with the
radiaiing aggregates of seconda:y hornblende above mentioned.
‘This mineral appears to have occupied a prominent place in the
original rock, where it largely replaced the bisilicates. Having
crystallized later than the quartz, it presents very seldom idiomorphic

58 _ MR, T. L, WALKER ON THE [Feb. 1897,

forms. The same mineral is a very frequent accessory in the
Norwegian zircon-syenites, though the secondary products are not so
well developed there as in the Onaping rocks. This mineral has
been identified in the zircon-syenites as wohlerite, and it is possible
that the associates of wohlerite may be found in the Sudbury nickel-
bearing rocks. A mechanical or chemical separation of this mineral
was impossible.

The reddish granite at Onaping Station is composed of micro-
pegmatite, orthoclase with a little free quartz, and about equal
quantities of wohlerite and secondary hornblende, which was pro-
bably derived from the former. Orthoclase has replaced plagioclase
in the micropegmatite, which constitutes about two-thirds of the
rock, and has attained a high degree of perfection. Wohlerite is
present as grains, which at times deserve the name of crystals, and
may be seen to be optically biaxial, with a very large optic angle.
The secondary hornblende derived from it contains numerous deli-
cate feathery crystals of biotite, which are also probably of secondary
nature.

South-eastward from Onaping, near the contact, the granite
becomes fine-grained and darker in colour, while the microscope
shows a slight increase in plagioclase and iron ores, and a decrease
in free quartz.

In this eruptive, as in the one previously described, micropeg-
matite is characteristic for the granitic rocks connected with basic
noritic borders. Harker has observed the same occurrence in his
studies of the Carrock Fell gabbro in England. Elsewhere micro-
pegmatitic rocks are generally muscovite-bearing, but in the Sudbury
eruptives muscovite is very seldom found. A wider examination
might show that micropegmatite is characteristic for all rocks which
are midway between the more acid and the more basic portion of
differentiated eruptives.

Some of the most important deposits of nickeliferous pyrrhotite
discovered in the Sudbury district are situated along the north-
western border of the Windy Lake eruptive. We have here to deal
with an eruptive whose length is unknown, and whose width is nearly
4 miles. The gradual transition, from typical pyrrhotite-norite on
the one hand to hornblende-granite on the other, shows that in most.
respects it is identical with the Whitson Lake eruptive. These
eruptive areas, which are bordered locally with norite and pyrrhotite-
norite, cannot properly be spoken of as basic eruptives, since the
average acidity for the whole of the eruptives is at least 62 per cent.
of silica. In this respect the Sudbury nickel-bearing eruptives differ
from those of Norway as described by Vogt.

Bell’s map shows a greenstone area extending from Lake Sagi-
tchi-wai-a-ga-mog south-westward into the township of Morgan.
This area is in all probability only a basic border of the Windy
Lake eruptive. In this case the length of the eruptive is at least.
25 miles, while further investigation may show that it is even
longer.

Vol. 53.] SUDBURY NICKEL DISTRICT (CANADA). 59

Specific-gravity determinations, of a series of specimens collected
along the railway where it crosses the Windy Lake eruptive, show
a decrease from each border towards the centre, where the lightest
and most acid rocks occur. The following numbers are averages of
pairs of specimens, so that the error inherent in determinations
made on small fragments is more or less eliminated :—

Hasterm contact: | 2.2... .<-e6 22. 2°714
\. Bi AY a ecee atts eae 2°746
‘5 Pru dus ce Ae ane 2°690
Onaping Station ............... 2722
be see tbe BT ar ee ee 2°793
Wesiern contact ............... 2°851

(iv) The Travers Mine Eruptive.

This nickel-bearing area is situated in the townships of Drury
and Denison, about 25 miles south-west of Sudbury. It is most
easily reached from Worthington Station on the ‘Soo’ branch of the
Canadian Pacific Railway. Bell maps it as being nearly a mile wide
and 6 miles long.

The rock on the dump at Travers Mine is fine-grained, dark
greenish-grey, and in some cases exhibits a schistose structure. The
microscope shows that it is composed of fine granular felspar, uralitic
hornblende, a very little hornblende-epidote, and iron ores. The
schistosity is often very distinct, and is caused by the bisilicates
forming lengthened, irregularly - pointed, elliptical areas, which
alternate with granular felspar-epidote masses, that constitute two-
thirds of the rock.

Farther south the rock is composed of the same minerals, but is
often much coarser. Locally there are small patches which are
nearly pure felspar-epidote aggregate, while in other places there
are dark patches which contain very little felspar-epidote aggregate.
A mile and a quarter south of the mine the rock becomes very much
coarser.

The rocks of this area resemble the well-known flaser-gabbros of
Rosswein, Saxony, and differ widely from the rocks of the two areas
already studied. At present it is composed of saussurite flaser-
gabbro, especially rich in saussurite. The flaser-structure has pro-
bably been caused by great pressure, which hastened the uraliti-
zation and saussuritization of the components, and may have pro-
duced the crushed granite north of the Travers Mine. I have not
determined the relation of the gabbro to the granite north of the
mine, but I think that the two are genetically distinct.

VY. Oruer Nickenirerous ARBAS.

The Stobie Mine is connected with a long narrow area of some-
what schistose greenstone, which is only a few yards wide where
crossed by the Blezard branch of the Canadian Pacific Railway.
The specimens collected indicate an approach to amphibolite. The
Huronian rocks have been metamorphosed by this now highly-altered.

60 _ MR. T, L. WALKER ON THE [Feb. 1897,

greenstone ; garnet and biotite are the chief new minerals, while
the whole rock has been rendered quite crystalline.

Copper Cliff Mine is also situated on a very narrow eruptive stock.
‘The greenstone is so much altered that its original nature is quite
concealed. The microscope shows that uralite, a little secondary
hornblende, plagioclase, free quartz, and a little micropegmatite are
the chief constituents. This rock is thus seen to be much more acid
than that examined at any of the other nickel mines.

Worthington Mine is connected with an eruptive which is not
more than 50 yards wide where the ‘Soo’ branch of the Canadian
Pacific Railway crosses it at Worthington Station. The rock is very
schistose, and greenish-grey in colour. Some of the fresher specimens
might be called actinolite-schist, while others are largely changed to
a fine aggregate of talc, which contains only a few slender actinolite-
crystals. Pyrrhotite-grains are richly scattered through the rock.

There are a few areas of hornblende-schist in the Sudbury district,
but it is difficult to determine whether they should be regarded as
crystalline schists and proper members of the Huronian, or as altered
greenstones. One of the largest and most accessible of these areas
is cut by the main line of the Canadian Pacific Railway, about
3 miles west of Sudbury. The rock is rather compact, distinctly
schistose, and nearly black in colour. The microscope shows that
it is composed of long, slender crystals of bluish-green hornblende,
a smaller quantity of quartz and water-clear grains of felspar.

Narrowly elliptical quartz-grains form parallel chains of inclusions
in the hornblende-crystals. These inclusions occupy a definite plane,
which, from the following observations, appears to be the positive
orthodome +Po. (The face usually marked p is here taken to be
the basis oP) :—

(i) In sections of hornblende-individuals the inclusion-chains
are at right angles to the cleavage—hence they lie in a
plane of the orthodiagonal zone.

(ii) The maximum extinction for sections parallel to oo Bo
is 18° 55’. Such sections show that the chains of inclu-
sions form an angle of 75° with the cleavage, and an

angle of 89° with the axis of elasticity

(iii) Sections with smaller angles of extinction give larger
angles between the cleavage and the inclusion-chains.

Similar disjointing of blade-like crystals by pressure is observed in
many minerals, particularly in the piedmontite of Japanese pied-
montite-schists. Parting of hornblende-crystals along +P has
been observed by Cross in actinolite-schists from Britanny, and also
less perfectly in green schists from Zermatt in Switzerland.

The same amphibolite-area may be examined about 4 mile north
of Copper Cliff Mine. The nickel-bearing rocks at Stobie Mine
resemble these amphibolites, and it is possible that they are all
connected.

Vol. 53. ] SUDBURY NICKEL DISTRICT (CANADA). 61

It is worthy of note that most of the narrow arcas of nickeliferous
rocks have been acted upon by dynamic metamorphism with com-
parative ease, and as a result the original unaltered rock is seldom
found in the smaller eruptives. The original rock was probably a
massive norite or gabbro, which was changed into schistose horn-
blende-rock. This is seen in the rocks of the Stobie, Travers, and
Worthington eruptives. On the other hand, large eruptives such
as the two first described have retained their massive structure and
to a large extent their pyroxene content.

As compared with the Norwegian nickeliferous rocks, the Sudbury
rocks are decidedly more acid, for olivine, which is a frequent con-
stituent of the former, has never been detected in any of the
Sudbury nickeliferous rocks.

VI. Tue Youncer GRANITEs,

We must now refer briefly to a class of granites which are younger
than the nickeliferous rocks, and may be conveniently spoken of
as ‘Younger Granites.’ The best exposures of these rocks occur
on the main line of the Canadian Pacific Railway, about 2 miles
west of Murray Mines. The nickel-bearing rocks are there cut by
two separate eruptions of fine-grained, pinkish biotite-granite, which
sends off apophyses into the surrounding greenstone. The wider of
these intrusions is about 100 yards broad, while the smaller is
less than 60 yards. The microscope shows that quartz, orthoclace,
plagioclase, and biotite are the chief constituents.

Where the rock comes into contact with the norite, the hy per-
sthene, hornblende, and augite of the latter are changed to fine scaly
biotite, while the well-formed plagioclase is replaced by an aggregate:
of granular plagioclase, epidote, and quartz.

Another exposure of this rock occurs immediately south-east of
Murray Mines, where it cuts through the nickeliferous greenstone,
sometimes forming apparent inliers in the same. In other places
breccias are formed by the inclusion of angular fragments of green-
stone in a groundmass of fine-grained pinkish granite.

It appears as if there had been an intrusion of this granite along
the contact between the nickel-bearing eruptives and the Huronian
rocks south-east of them. The width of this granitic intrusion is
over 3 mile. It contains numerous inliers of greenstone. A narrow
strip of mica-schist 11 yards wide is exposed along the railway
on the south-eastern border of the granite. The schist dips at
very high angles, and doubtless represents the rock which was
originally in contact with the nickel-bearing eruptive. Similar
exposures of fine-grained granite are observed immediately south
of Blezard Mine.

North of Copper Cliff Mine there is a large area of coarse
gneissoid granite, which the late Baron vo. Tontlon considered to be
Laurentian. It is essentially the same rock os that exposed east of
Murray Mines, except that the latter has been so crushed as to
present a much finer grain,

62 MR, T. L. WALKER ON THE [Feb. 1897,

VIL. Oxrvine-Drapase Drxes.

These dykes are the youngest of the Sudbury rocks, and are
characterized by north-westeriy direction with only very slight
variations. All the other rocks of the district are intersected by
them. The extensive area over which these dykes occur, taken in
connexion with their general parallelism, points to a period of great
dynamical action. The force that produced the cracks through
which the diabase-magma ascended had doubtless a part in the
production of amphibolites and flaser-gabbros from massive pyroxene-
rocks, in the metamorphism of the norites, and in the crushing of
the Younger Granites and granitic borders of the nickel-bearing
areas, As the dykes intersect all the other rocks, we may conclude
their post-Huronian age, though it is impossible to say whether they
were formed in early Paleozoic or in comparatively recent times.

One of the best representatives of this dyke-system is well exposed
quite near the town of Sudbury, and can be followed for 7 miles.
The easternmost exposure is on the southern shore of Ramsay Lake,
near the north-western point of the peninsula which nearly divides
the lake. It appears again on the north-western shore near the
landing, and the dyke may be followed by frequent exposures past
the town of Sudbury. All the exposures of diabase along the
railway between Sudbury and Rayside Stations are portions of the
same dyke.

Another dyke of this system crosses the railway 1 mile east of
Worthington Station, and a third about 7 mile east of the station.
A very large dyke is well exposed on the railway near Nairn Station.
Many others might be mentioned, some of which are said to have
other directions, but all those examined by the writer have a general
north-westerly direction. In width they vary from a few feet to
50 yards.

Plagioclase is the chief constituent. It is generally quite fresh,
but is occasionally somewhat clouded. Idiomorphic much-twinned
crystals are characteristic. From measurements of the angles of
extinction the felspar seems to be labradorite. The twinning is
commonly of the albite law, but a combination of the albite and
pericline laws is frequent. In a section from the large dyke near
Murray Mines twinning was observed combining the albite, pericline,
and Baveno laws. Twinning of plagioclase according to the Bayeno
law was first mentioned by Weiss, and more fully described by
Brezina. The combination of this rare twinning law with the albite
and pericline laws as exhibited in the diabase from near Murray
Mines is very interesting, and probably has never been previously
observed. Plagioclase being by far the earliest to crystallize, the
ophitic structure is beautifully developed. |

The quantity of monoclinic pyroxene varies. In the exposure
near Murray Mines it forms about a quarter of the rock, while at
other points on this dyke, as also in the dykes near Worthington
Station, it does not constitute more than an eighth of the rock.
Where there is most pyroxene there is least olivine, and vice versd,

Vol. 53.] SUDBURY NICKEL DISTRICT (CANADA). 63

so that the total quantity of pyroxene and olivine is nearly constant.
The olivine forms more or less rounded, pale greenish-yellow grains,
which are younger than the plagioclase, but older than the augite.
Sometimes the olivine has given rise to small quantities of serpentine
and swarms of minute grains of magnetite. The pyroxene shows
no definite outline, and very seldom imperfect cleavage : it is reddish-
brown to violet in colour, and distinctly pleochroic. The usual
accessory minerals are present, and the rock is remarkably fresh.

One point characteristic of these dykes is the ease with which
they are acted upon by hydrochemical agencies. Near the village
of Murray Mines the Government road passes for some distance
between high walls of granite, which have become prominent by the
weathering-out of the diabase. The nickel-bearing greenstones
resist the action of atmospheric agencies much better, and are
generally greenish on the weathered surface. In this respect they
stand in contrast to the rocks under discussion, which become quite
rusty on exposure. Spheroidal weathering is characteristic.

One of the exposures on the railway immediately east of
Worthington Station contains porphyritic crystals of plagioclase
from 1 to 2 inches long. This porphyritic phase is confined to
within 2 yards of the contact. No glassy borders were observed in
connexion with these dykes, but this may be due to the ease with
which the rock decays. The large dyke, where exposed on Ramsay
Lake, exhibits a gradual change in.texture from very fine at the
borders to quite coarse in the central portions. A microscopic
examination of the marginal and central portions shows that they
are mineralogically identical, and that there has been no differen-
tiation. This is confirmed by specific-gravity determinations of a
series of specimens representing a cross-section of the dyke where
its width is about 40 yards.

A quantitative analysis of a specimen from the big dyke near
Murray Mines gave the following result :—

“/o

SoC Jauleecas, Rata ae Seaegte 4722
SALT, Ore sate ee aetie eels a 16°52
GOs Peo secede ed ole 3°32

LO ey Se eae ees Oe 12-40
WENO rece tesa eee ee 0:04
DAO OAs. ce daoae sseseues 9°61
MO eine ee aes sets: 3°33
BRO) i tie Seca os Ra ea Punches 0°67
lINiee On ae a2 nae Seucanesroes 3°40
EO Fr cic tenn sccran cate aes ais 3°62
JE 0 eee eee ene 0:33
EO Pei ana Aamo outinns 0-01
OW hiacdea tnteios sdanes trace
13,1 SJ agen ef od 0:0275
COON ioe. vectls 0:0055
Loss by ignition ......... 0:30

loa Je cis ye salve 100°803

Specific gravity ......... 3°01

Grotoetcat SxrrcH-MAP oF THE SupBuRY DistrRi07.

%
Avs
ar

SARSON

$444tttt f;
Ft teas peget| ttre ttt
AEH Feet page pee et tte

tHe te ttt pettt
tH Se at
LAP bbe d tht tt ed

tette ptt +t
ttted Fett +] 4
tet ttttet +
+ttt ta444)4
ee
Steer beets
tet spp pet
+1+

ut us ut =
oc S
= =Sss 7 |e =
a = S29 9% g 12 Ws:
= =) «< 0 E
iS ub no =
a i VE oo{s z= Zz
z= < ag re ia so S)
ie 2 s cA4\ fe ou
g oS § 2

EnelisH Mites.

0

Se eee

4

— = Railway-lines,

Nol. 54%] THE SUDBURY NICKEL DISTRICT (CANADA), 65

The proportions of ferrous oxide and titanic acid are unusually
large. The latter doubtless occurs partly in the magnetite and
ilmenite and partly in the augite, giving this last its peculiar violet
colour. It has long been known that nickel is a frequent constituent
of the heavy ferro-magnesian minerals, especially of olivine and
pyroxene, and it is probable that the heavy metals contained in the
diabase are constituents of these silicates. Whether the nickel,
cobalt, and copper were primarily constituents of the diabase-magma
or not would be difficult to say, as they may have been derived from
the nickel-bearing greenstones which are intersected by these dykes.
Fragments of the nickel-bearing rocks may have been absorbed by
the diabase-magma. I am, however, inclined to regard the nickel
content of the diabase as a constituent of the original diabase-
magma. No nickel-deposits have been found associated with these
dyke-rocks.

Had the nickeliferous diabase solidified more slowly and been
richer in sulphur, the nickel would probably have separated as iron-
nickel sulphides along the border, as it did in the case of the nickel-
bearing greenstones, where these differentiations of pyrrhotite-norite
now constitute the most extensive nickel-deposits in the world.

The map which accompanies this paper is founded on that issued
by the Canadian Geological Survey. It differs, however, in two
ways from the Government map. Firstly, I have omitted much of
the detail both in topography and geology, and have reproduced only
such features as are necessary to illustrate the present paper. The
second difference is wholly geological, and consists in such changes
as my own explorations showed to be necessary. These changes
are principally connected with the Whitson Lake and Windy Lake
eruptives, and with the Younger Granites.

The investigations reported in this paper were carried on under
the direction of Herr Geheimrath Professor Zirkel. It affords me
great pleasure to acknowledge my indebtedness to him for his
friendly advice and encouragement.

VIII. Lrreratvre.

Apams, F. D. ‘On the Igneous Origin of certain Ore Deposits.’ Mining
Association of the Province of Quebec. Montreal, 1894.

na th EH. ‘Nickel and Copper Deposits of Sudbury.’ Ottawa Naturalist,

Beut, Rosert, ‘The Nickel and Copper Deposits of Sudbury, Canada.’ Bull.
Geol. Soc. Am. vol. ii. (1891) pp. 125-187.

——. ‘Report on the Sudbury Mining District.’ Geol. Survey of Canada,
1891, Ann. Rep. pt. i. F.

Bonney, T.G. ‘Notes on a Part of the Huronian Series in the Neighbour-
hood of Sudbury, Canada.’ Quart. Journ. Geol. Soc. vol. xliv. (1888)
pp. 32-44.

Fouuton, H. B. von. ‘Ueber einige Nickelerzvorkommen.’ Jahrb. d. k.-k.
geol. Reichsanstalt. Vienna, 1892, pp. 223-310.

Garninr, J. ‘Mines de Nickel, Cuivre et Platine du Sudbury, Canada.’ Mém.
Soc. des Ing. civils. Paris, 1891.

Q.J.G.8. No. 209. F

66 THE SUDBURY NICKEL DISTRICT (CANADA). [ Feb. 1897,

Mickur, G. R. ‘The Relation between Pyrrhotite, Gangue, and the accom-
panying Rocks of the Sudbury District.’ Sudbury Journal, 1894.

Peters, EK. D., Jun. ‘Sudbury Ore Deposits.’ Trans. Am. Inst. Min. Eng.,
vol. xviii. (1890) p. 278.

Setwyn, A. R. C. ‘ Descriptive Sketch of the Physical Geography and Geology
of the Dominion of Canada.’ Geol. Survey of Canada, 1884.

Stratzner, A. W. (Notes on Sudbury Rocks, communicated by G. R. Mickle.
Sudbury Journal, 1894.)

Voer, J. H. L. ‘Bildung von Erzlagerstatten.’ Zeitschr. f. prakt. Geologie,

1893-1894.

‘ Nikkelvorkomester og Nikkelproduktion.’ Kristiania, 1892.

Waker, T. L. ‘Diabase Dykes in the Sudbury District. Trans. Ontario
Mining Institute, 1895.

Wituiams, G. H. ‘Notes on the Microscopic Character of Rocks from the
Sudbury Mining District, Canada.’ Geol. Survey of Canada, 1891, Ann.
Rep. pt. i. F. App. i.

Discussion.

The PrestpEnt said that all additional information in regard to
the Huronian rocks, which resemble so closely the volcanic rocks of
pre-Cambrian age in Wales, was most useful at the present time.
The Author’s paper, therefore, was one in which British geologists
would necessarily be much interested.

Prof. Bonney said that, so far as he had seen the district, he doubted
whether the ore was the result of differentiation. He believed
that it was more likely to have been introduced afterwards, as is
commonly the case with mineral ores. He thought also that the
Author was pushing this idea of differentiation too far in regard to
the rocks of the country. So far as he knew, there was a number
of separate bosses of various kinds of rocks.

Mr. Tratt said that hyperites were associated with the Loch Dee
granite in the South of Scotland, and that pyrrhotite occurred in
some of the altered forms of these rocks. This pyrrhotite, however,
in the specimen he had examined was certainly not nickeliferous to
anything like the same extent as the Swedish and Canadian varieties.
The. association of nickeliferous pyrrhotite with hyperites and
norites was now known from a very large number of localities in
various parts of the world, and the differentiation-hypothesis had
been advanced by Vogt to explain the association. }

The paper was based on a large amount of field as well as labora-
tory work. Its main object was not to establish a theory, but to
describe facts.

Gen. M°Manon referred to the theoretical portion of the paper,
and commented on the difficulty of understanding how the law of
‘gravitation could be appealed to as the explanation of the basic
portions of slowly-cooling magmas concentrating in the centres of
eruptive masses, combined with the formation of acid rocks on both
margins.

The Rev. J. F. Buaxz also spoke.

Wal. 537 THE FAUNA OF THE KEISLEY LIMESTONE. 67

5. The Fauna of the Kutstuy Limestonr.—Part II. Concruston.*
By F. R. Cowper Reep, Esq., M.A., F.G.S. (Read November

18th, 1896.)
[Prats VI.]

OSTRACODA.

Or the rich fauna of ostracods which Prof. T. Rupert Jones * has
described from Kildare I have, after careful search, been able to
-determine only the following two at Keisley :—

Primitta M‘Coyt, Salter.

This is the form which many previous observers have recorded
as Cythere phaseolus (His.), but it is a mistaken identification,
as Prof. Rupert Jones (loc. cit.) has shown. The species is as
abundant at Keisley as it is at Kildare.

CyYTHERE WRIGHTIANA, Jones.

This is a rare form at Keisley, only two or three specimens
having so far been found.

BRACHIOPODA.

OBOLELLA cf. NITENS, Hisinger.

A small transversely-oval shell, with a longitudinal groove from
the beak to the anterior margin, appears to belong to this Swedish
species.’ The shell is very thin, and marked with only a few con-
centric lines of growth; the brachial valye, which here is alone
preserved, is much flattened, has a small pointed beak near the
margin, an almost straight hinge-line, and a distinct longitudinal
groove running from the beak to the front edge. The brachial valve
of this species figured by Lindstrom * corresponds very closely in
shape and other characters with our Keisley specimen, but the
pedicle-valves there delineated are subcircular, and described as
shield-shaped, though the breadth is given as twice the length.
The species is found in the T'rinucleus-schists of Sweden. Our
specimen measures 2 millim. in length and 3 in breadth.

ORBICULOIDEA, Sp.

A small circular pedicle-valve, ornamented with rather coarse
concentric striz, and possessing a central elevated umbo whence a
narrow external pedicle-groove is traceable to the margin, is the only
representative of the genus that I have seen from this rock. The
specimen is in the Woodwardian Museum.

1 For Part I., see this Journal, vol. lii. (1896) pp. 407-437 & pls. xx.-xxi.
2 Ann. Mag. Nat. Hist. ser. 4, vol. ii. (1868) p. 54, pl. vii.
8 Hisinger, ‘ Lethza Suecica,’ Stockholm, 1837, p. 77 (Atrypa? nitens).
4 «Fragm. Silur.’ (1880) pl. xiii. fig. 34.
F2

68 MR. F. R. COWPER REED ON THE [ Feb. 1897;

It cannot be identified with Discina gibba (Lindstr.) of the
Leptena-Limestone, for that species has two small nodules below the
apical foramen, and the beak of the pedicle-valve is subcentral and
nearer the posterior than the anterior margin. Davidson ' figures a
small species of Orbiculoidea (Discina, Day.), from Keisley, which
is apparently distinct from that above described.

Linevra ?, sp.

Prof. Harkness ° records Lingula brevis? (Portl.) from the Keisley
Limestone. I have seen the specimen thus identified at Carlisle,
and am very doubtful about it. It might even not be a brachiopod
at all, but a lamellibranch, like Ambonychia? nux (Lindstr.), which
Lindstrom * figures and describes from the Leptwna-Limestone.

OrTHIsS CALLIGRAMMA, Dalm.

This species is not common at Keisley.

ORTHIS CALLIGRAMMA, Var.

In addition to specimens with the ordinary features of this
well-known species, there has been found the imperfect brachial
valve of an Orthis having the shape and appearance of typical
individuals of this species, but furnished with thirty to forty rounded,.
straight, simple ribs of regular width, separated by interspaces which
at the margin of the valve are more than double the breadth of
the ribs, except near the hinge-line, where the last six or seven
ribs are somewhat crowded together and of rather smaller size.

Ortuis Actonrz, Sowerby.

This is a rare species in the Keisley rock. Probably Orthis:
Oswaldi (Von Buch), which occurs in Stage F of the Kast Baltic
provinces, is a synonym, as Schmidt * mentions. It is found also in
the Kildare and Leptena-Limestones.

Orruis (Bitoprres) BILOBA, Linn.

Though a characteristically Silurian species, this is not unknown
from Ordovician beds, and Davidson ’ records its occurrence at Cefn
Rhyddan and other places in Bala rocks. J have seen several well-
preserved specimens from Keisley, two of which I found myself.
It occurs in the Leptena-Limestone.

OntHis (PLATYSTROPHIA) BIFORATA, Schlotheim.

A fairly common species at Keisley. The Kildare and Leptena-
Limestones and Schmidt’s Stage F also contain it,

1 «Mon. Brit. Foss. Brach.,’ vol. iii. (1864-71) pl. 1. fig. 27.

2 Quart. Journ. Geol. Soe. vol. xxi. (1865) p. 248.

3 «Fragm. Silur.’ (1880) p. 17, pl. xiii. figs. 53, 54.

4 ¢QOn the Silurian (and Cambrian) Strata of the Baltic Provinces of Russia,”
Quart. Journ. Geol. Soc. vol. xxxviii. (1882) p. 514.

5 § Mon. Brit. Foss. Brach.,’ vol. iii. (1864-71) p. 206.

Vol. 53.] FAUNA OF THE KEISLEY LIMESTONE, 69

Ortuis (DALMANELLA) TESTUDINARIA, Dalman.

Not very common at Keisley. It has not been recorded so far
from the Kildare or the Leptena-Limestone.

‘Ontuis (DaLMANELLA ?) cf. conrertA, Lindstrém.

Lindstrom ! describes and figures a small species of Orthis from
the Leptena-Limestone under the name of O. conferta. Some
specimens from Keisley appear to belong to it, agreeing in shape
and surface-ornamentation.

‘OrtuIs cf, ARGENTEA, Hisinger.

I have but little doubt that this species of Hisinger’s? occurs at
Keisley, for several well-preserved shells show all the typical
external features with the regular bifurcation of the ribs, but they

are of rather large size. In Sweden it occurs in the T'rinucleus-
Schists.

Orntuis (HeBERTELLA?) KEISLEYENSIS, sp.n. (Pl. VI. figs. 1, la, &10.)

This species is founded on a single pedicle-valve of a small speci-
men, but it shows characters so ‘peculiar and distinct that a new
specific name is not uncalled for.

The valve is transverse, with a sotnietvenlak outline. The depth
at the umbo is nearly one-third of the total length. There is a
very faint indication of a median sinus; the beak is small, and not
curved over the hinge-line.

The hinge-line is straight, and there is a high, triangular, steeply
inclined hinge-area. The surface of the valve is ornamented with
about sixteen simple, straight, unforked, narrow, rounded ribs
extending from the beak to the margin, with interspaces of quite
double the width of the ribs.

The ribs and interspaces are crossed by strong, rounded, raised,
equidistant, concentric lines, not lamellose; these give a distinct
cancellated appearance to the surface.

The length of the valve is 5 millim., and its width 6 millim.,

In the shape of the pedicle-valve and the characters of the hinge-
area, this Keisley form resembles the species belonging to the group
Hebertella of Hall & Clarke,* but none of the species, so far as I
know, have a precisely similar ornamentation.

In these respects also the common Wenlock species, Orthis Bou-
chards (Davidson), is not unlike our specimen, but it has fewer ribs
and the concentric markings are lamellose,

ORTHIS VESPERTILIO, Sowerby.

There is a specimen in the Carlisle Museum from Keisley, but it
is arareform. It probably occurs at Kildare.

‘Fragm. Silur.’ (1880) p. 26, pl. xiii. figs, 1-3.

2 Tbid. pl. xiv. figs. 12-15 ; and Hisinger, ‘Lethza Suecic.’ (1337), p. 72,
pl. xx. fig. 15.

3 «Pal. N.Y.,’ vol. viii. Brach. pt. i. (1892) p. 198.

70 MR. F. R. COWPER REED ON THE [Feb.2Go7—

Ortuis (DALMANELLA) ELEGANTULA ?, Dalman.
OrrHis (HETERORTHIS) ALTERNATA ?, Sowerby.

OnTHIS (DINORTHIS) FLABELLULUM ?, Sowerby.

These three species have been doubtfully identified from frag-
mentary specimens.

STROPHOMENA ANTIQUATA, Sowerby.

A fairly common species at Keisley ; it is found in the Bala, as:
well as in the Silurian of Britain.

STROPHOMENA CORRUGATELLA, Davidson.

This is one of the commonest species at Keisley, and is also
found at the Chair of Kildare and in the Leptena-Limestone.

LEPTHNA RHOMBOIDALIS, Wilckens.

This species, commonly but erroneously’ called Strophomena
rhomboidalis, is not abundant in the Keisley Limestone, but it has
been recorded thence by Harkness, Marr, and Nicholson, and I have
found good typical specimens of it myself. It occurs also in the
Kildare Limestone and in the Dalecarlian Limestone.

PrectamBonitEs Scumipti, Tornquist.

It is of considerable importance that this species has been recog-
nized at Keisley, for it appears to be nearly restricted to the horizon
of the Leptena-Limestone and Stage F of Schmidt. I have not seen
any specimens from Kildare, but the Keisley examples show all the
features described by Lindstrom.”

PLECTAMBONITES QUINQUECOsTATA, M‘Coy.

Toérnquist * compares a Leptena-Limestone species with this one of
M‘Coy’s, but it is not given in the ‘ List of the Fossil Faunas of
Sweden’ (Stockholm, 1888). It is fairly common at Keisley and
Kildare.

PLECTAMBONITES TRANSVERSALIS ?, Wahlenberg.

I believe that this species occurs at Keisley, but the specimens
are rather imperfect. It occurs also doubtfully at Kildare. It is
known from Bala, Llandovery, and Wenlock rocks in the United

Kingdom.*
RAFINESQUINA EXPANSA, Sowerby.

There is a well-preserved ventral valve of this species at Carlisle,
and I have seen other fragments. Davidson’ states that this form
is found in the Caradoc and Lower Llandovery.

1 Hall & Clarke, ‘Pal. N. Y.,’ vol. viii. Brach. pt. i, (1892) pp. 250 & 276.;
* * Fragm. Silur.’ (1880) p. 29, pl. xiv. figs. 25, 26.
3 «Ofvers. 6. Bergbyggn. inom Siljans. i Dal. p. 26, Sveriges Geol.
Undersokn. ser. C, no. 57 (Stockholm, 1883).
4 Davidson, ‘Mon. Brit. Foss. Brach.,’ vol. 111. (1864-71) p. 320 (Leptena

transversalis).
5 Ibid. p. 314 ( Strophomena expansa).—

Vols set FAUNA OF THE KEISLEY LIMESTONE. (as

RaFINESQUINA DELTOIDEA, Dalman.

The typical form of this species occurs at Keisley, and perhaps at
Kildare, but is rare. Itis recorded from Stage F of the Kast Baltic
provinces by Schmidt.'

RaFINESQUINA (?) DELTOIDEA, var. UNDATA, M‘Coy.

This variety is not uncommon at Kildare and Keisley. I strongly
doubt whether it is really a variety of &. deltoidea and not a distinct
species belonging to another genus, Lindstrom? figures and de-
scribes a variety of Stropheodonta imbrex (Pander) which seems to be
almost identical with the Keisley form. The latter agrees best with
fig. 23, pl. xxxix. vol. iti. of Davidson’s ‘ Monograph of the British
Fossil Brachiopoda.’ The Swedish specimens, however, which are
from the Leptewna-Limestone appear to be less suddenly geniculated
and to possess a greater number of larger ribs than those from
Keisley and Kildare.

TRIPLECIA INSULARIS, Eichwald.
This species occurs at Keisley, Kildare, and in Stage F.

STREPTIS MONILIFERA, M‘Coy.

This form appears to be almost restricted to Keisley and Kildare,
where it is abundant.

CHRISTIANIA TENUICINCTA, M‘Coy.

This is a very common species at Keisley, and is also found at
Kildare. The peculiar internal structure and muscular impressions
have recently led Messrs. Hall & Clarke to establish the new genus
Christiania for the reception of this species, which previously was
ealled a Leptena.

ATRYPA EXPANSA, Lindstrom.

This species * is very variable, but is distinguished from A. mar-
gmalis (Dalm.) by its subquadrate form and diminished prominence
of the beak of the ventral valve. Three fairly distinct varieties
oceur in the Keisley Limestone. The first (var. «) is characterized
by the almost obsolete fold on the brachial valve, while the sinus on
the pedicle-valve is fairly strong. The marginal fringes to the
valves,.such as Davidson figured in the case of A. reticularis, are
frequently preserved.

The second variety (3) has the fold on the brachial valve distinct,
but the ribs on the valves are much smaller and more numerous
than in the type-form. Thus I have counted as many as ten ribs
on the brachial fold of one specimen. The marginal fringes are often
present in this variety also. The third variety (y) is characterized
by the possession of a strong angular sinus in the pedicle-valve,

1 ‘Rev. d. ostbalt. Silur. Trilob., pt. i. Mém. Acal Imp. des Sci.
St. Pétersbourg, ser. 7, vol. xxx. (1881) no. 1, p. 38.

> «Fragm. Silur.’ (1880) p. 29, pl. xiv. figs, 27-32.

3 Ibid. p. 22, pl. xii. figs, 6-10, 17-19.

72 MR. F. RB. COWPER REED ON THE [Feb. 1897,

furnished with a single median rib. The brachial valve has a low
median fold, marked by two ribs and a somewhat wide interspace
on each side between the fold and the lateral group of ribs. The
cardinal angles of the shell are more rounded than in the type-form.
I was at first inclined to remove this form into a new species, but
perhaps it is safer at present merely to consider it a variety of
A, expansa. It apparently occurs in the Leptena-Limestone.

ATRYPA MARGINALIS (Dalman).

There is no reason to doubt that this species or a variety of it
occurs in the Keisley Limestone, as its characters are sufficiently
distinct from those of A. expansa in its typical form.

ATRYPINA SIMILIS, sp. n. (PI. VI. figs. 2, 2a, 26, 3, & 3a.)

Shell small, subcircular, retziform, flattened. Pedicle-valve more
convex than the brachial valve, and furnished with a prominent beak
pierced by a distinct circular foramen with a deltidium (of one piece ?)
in front. The surface of this valve is traversed by seven radiating
rounded ribs extending from the beak to the margin; of these the
median one bifurcates close to the beak into two strong rounded
ribs, each of which again bifurcates at about half its length. The
other ribs are simple, and decrease in strength near the hinge-line.,

Brachial valve flattened, more convex posteriorly, with small
inc nspicuous beak and shallow mesial sinus, widening anteriorly.
In this sinus lies a single rounded rib which arises at a point about
half the length of the shell and bifurcates into two weaker ribs
which reach the margin. On each side of the sinus is a strong
rounded rib, arising from the beak and bifurcating, at about half its
length, into two weaker contiguous ribs reaching the margin like
the central one in the sinus. (In the young form, Pl. VI. fig. 2a,
these ribs do not bifurcate.) On each lateral portion of the valve
- outside these ribs bordering the sinus are three simple ribs, those
nearest the hinge-line being the weakest.

millim.,
Tenth obs slell iecnn gests wcustecar eleva. lemaynes 98 69~ 55
VCR UGH eek ee Meee rt cataneetsre cas cee a 5:0

This species much resembles Atrypa Barrande: (Davidson) ' in
shape and general characters, as well as in the distribution of the
ribs on each valve. But it differs in the bifurcation of certain of
these ribs and in the absence of the concentric-growth ridges.

Hall & Clarke * have recently designated the group of shells to
which Atrypa Barrandei belongs by the generic term of Atrypina.
Our Keisley species is especially closely allied to A. disparilis
(Hall) * of the Niagara Group, and also much resembles the type of
the genus A. imbricata (Hall) * from the Lower Helderberg Group.

' Davidson, ‘Mon. Brit. Foss. Brach.,’ vol. iii. (1864-71) p. 128, pl. xiii.
figs. 10-13; vol. v. Suppl. Sil. Brach. (1882) p. 114, pl. vii. figs. 7-7 0.

2 ¢Pal. N. Y.,’ vol. viii. Brach. pt. ii. (1894) p. 161.

3 Ibid. vol. ii. (1852) p..277, pl. lvii. fig. 6.

* Ibid. vol. iii. (1859) p. 246, pl. xxxviii. figs. 8-13.

Vol. 53.] FAUNA OF THE KEISLEY LIMESTONE, 73

But the distribution and furcation of the ribs are shown by the
figures of these American species to be slightly different.

CamMERELLA ? THomsontr (Davidson).

This species, which Davidson! doubtfully put in the genus
Rhynchonella, resembles in external characters Billings’s Camerella
Volbortht® from the Black River Limestone of Canada and Torn-
quist’s Camerella angulosa® from the Leptena-Limestone. I think,
therefore, that it is safer to assign it to the genus Camerella than
to Rhynchonella, used in its old wide sense.

Davidson gives only Craighead Quarry and Penwhapple Glen as
the localities in which this species has previously been found.

SYNTROPHIA AFFINIs, sp.n. (PI. VI. figs. 4 & 4a.)

Hall & Clarke * have recently established the new genus
Syntrophia for a small group of brachiopods which externally
resemble Billingsella and Protorthis, but in their internal structure
are related to the genus Stricklandinia of a later date. A single
pedicle-valve of a species of this genus Syntrophia from the Keisley
Limestone is in the Woodwardian Museum, bearing a close resem-
blance to Whitfield’s species Syn. lateralis, from the Calciferous
formation of America. Our specimen is transversely elongate,
strongly convex, with a straight hinge-line nearly equal to the
greatest width of the shell. The valve is divided into two rounded
convex lobes by a smooth sinus commencing a short distance in
front of the umbo, and extending with increasing width to the
anterior margin, which it gently sinuates. The umbo is small, not
prominent, but incurved over the hinge-line. At the cardinal-
lateral angles there is a slight flattening of the convexity of the
lobes of the valve in the vicinity of the hinge-line. The surface of
the valve is smooth, except for 4 few concentric strie, of which the
marginal ones are more strongly incised than the others.

As to the internal structure of the valve, the median septum is
seen through the thin shell to extend forward from the beak for
about two-thirds the length of the shell, but the spondylium
formed by the dental plates is not visible.

The points in which our species differs from Syn. lateralis
(Whitf.) are the inferior height and prominence of the umbo, and the
more clearly defined and rounded median sinus.

millim
Green ria BGI ore Sie 2) 0 OT ee Ie bese 3
eae bee Thee tects Ue he eh oe ie od ee Shik dw 5

RHYNCHOTREMA cf. DENTATUM, Hall.
The species Rh. dentatum occurs in the Trenton Limestone of

+ ‘Mon. Brit. Foss. Brach.,’ vol. iii. (1864-71) p. 186, pl. xxiv. fig. 18.
i 2 ‘ a Naturalist & Geologist,’ vol. iv. (1859) pp. 301, 302 & 445,
figs. 23, 24.
* *Om Lagerfolj. i Dal. undersilur Bildn.” Lunds Universitets Arsskrift,
vol. iii. (1866) p. 17; Lindstrém, ‘ Fragm. Silur.’ (1880) p. 23, pl. xiii. figs. 14-19.
“ «Pal. N. Y.,’ vol. viii. Brach. pt. ii. (1894) p. 216, pl. lxii. figs. 1-10.

74 _ MR. F. R. COWPER REED ON THE [Feb. 1897,

America, from which it was first described by Hall’ under the
name of Atrypa dentata. Recently it has been assigned by Hall &
Clarke* to the genus Rhynchotrema. The species much resembles
fihynchonella? cemula (Salter MS.) described by Davidson * from
the Kildare Limestone, but in this Irish form the mesial fold of the
brachial valve becomes biplicated only near the front margin of the
shell, and the two short rounded ribs on each side of it are confined
to the edges of the valve. In Rh. dentatum, on the other hand, the
mesial fold is strongly biplicated nearly from the beak, while each
lateral portion is furnished with three simple, slightly curved ribs,
extending entirely from the beak to the margin. The ‘zigzag
filiform lines’ which Hall describes in the American individuals
are also distinguishable on the ribs of our specimen.

The American specimens appear to have rather sharper and more
angular ribs than the Keisley form. This, however, is the only
point of difference that I have been able to detect.

Dayidson’s Rhynchonella decemplicata,' from the Bala and Upper
Llandovery beds, has more numerous ribs on the lateral portions,
but otherwise, so far as external characters go, much resembles
thynchotrema dentatum.

Wienethyorsmell |“ sigekt. cosas. Seda kenn aieenmesiseoes
UPOAOI LH oe ctadodic anivcteat nw decmaeeueivectcehnmiddocae desea 4

DaYIA PENTAGONALIS, sp. n. (Pl. VI. figs. 5, 5a, 56, & 5c.)

Shell subpentagonal, broadest across the middle, biconvex.
Hinge-line curved. Nohinge-area. Pedicle-valve more convex than
the brachial valve, especially near the beak; beak closely curved
over the hinge-line, concealing foramen. Beak of pedicle-valve
furnished with a longitudinal, broad, rounded keel; at about one-
third the length of the valve a shallow median furrow begins on
this keel or ridge, and extends to the front margin, increasing in
width anteriorly and thus making a double keel on the anterior
portion of the valve. The lateral portions of the valve on the slopes
of the median keel are slightly excavated, and are bounded posteriorly
on each side by a small narrow fold starting from the side of the
beak and curving round in its outward course to the end of the
hinge-line, so as to give the appearance of a false hinge-area
between it and the hinge-line, as in some Rhynchonellids.

The brachial valve is more convex posteriorly than towards the
front margin. A shallow groove begins close in front of the umbo,
and extends forward, with a steadily increasing width and depth,
to the anterior edge of the shell, where it has a smooth flattened
floor with low, steep, and abrupt sides. The lateral portions of this
valve are gently convex.

The anterior margin of the shell is broadly notched, owing to the
meeting of the median sinuses of the opposite valves. In the
umbonal cavity of the pedicle-valve are seen two short, divergent,

1 ‘Pal. N. Y.,’ vol. i. (1847) p. 148, pl. xxxiii. fig. 14.

2 Ibid. vol. viii. Brach. pt. i, (1894) p . 182.

3 «Mon. Brit. Foss. Brach.,’ vol. iii. (1864-71) p. 188, pl. xxiv. fig. 21.
+ Woid. ap. Vit, pl. xxii, figs. 20-24.

Vol. 53. | FAUNA OF THE KEISLEY LIMESTONE. 75

dental plates; and a long, low, median septum or ridge extends for
about two-thirds of the length of the brachial valve.

A brachidium with spiral cones of the type of Dayia is present,
but its details have not been made out, owing to lack of material on
which to experiment.

millim
Ronen lof shell 2c.cwsesine sesec vee neatecnceceneeaee 85
SCALE ec giem on geateet tee seed DoS 5 eee | 8:0

Affinities —The extraordinarily close external resemblance of
this species to Emmons’s Cyclospira bisulcata* of the Trenton Lime-
stone led me at first to the view that it must belong to the same
genus. With the exception of the absence of the median fold in
the sinus of the brachial valve, the resemblance appears to be com-
plete. But on developing the interior of the shell I have been able
to demonstrate that the brachidium is of the type of Daya navicula,
which is entirely different from the American genus Cyclospira, as
Hall & Clarke have recently shown.’

I do not know whether Tornquist’s species Dayia pentagona (MS.)*
is synonymous, as no description or figure has been published. But
the latter species is from the Leptena-Limestone, and I have seen
specimens of the form which JI have above described from the same
rock. There is a specimen of this shell from the Chair of Kildare
Limestone, labelled <Atrypa navicula (var.), in Sir R. Griffith’s
Collection in the Dublin Museum.

Hyatretira Portrock1ana (Davidson).

Davidson described this species more than 25 years ago from
the Limestone of the Chair of Kildare,’? and subsequently (in his
Supplement to the Silurian Brachiopoda) from the Upper Llandeilo
of Balcletchie, Girvan. The external characters of the shell
were alone given, and it was assigned doubtfully to the genus:
Rhynchonella. Lindstrom’ placed it in the genus Athyris, but
does not mention his reasons for so doing. I have been able to
expose the internal structure with some completeness, and to
demonstrate the presence of spiral lamella, necessitating the removal
of this species both from the genus Rhynchonella and from the
genus Athyris.

There are two fairly distinct varieties of this species—a long one
and a broad one. The elongated ovate form is that figured by
Davidson ; those illustrated by Lindstrom are rather broader and
more globose, and pass into the transverse or broad variety. Inter-

* *Geol. New York,’ Rept. Second Distr. (1842) p. 395, fig. 4 (Orthis bisulcata) ;
Hall, ‘Pal. N.Y.,’ vol. i. (1847) p. 189, pl. xxxiii. fig. 3 (Atrypa bisulcata) ;
Hall & Clarke, bid. vol. viii. Brach. pt. ii. (1894) p. 146 ( Cyclospira bisulcata).

? Davidson, ‘ Mon. Brit. Foss. Brach.,’ vol. iii. (1869) p. 190, pl. xxii. figs, 20-
23; vol. vy. Suppl. Sil. Brach. (1882) p. 96, pl. v. figs. 1-4.

3 ‘Pal. N. Y.,’ vol. viii. Brach. pt. ii. (1894).

* EH. Stolley, ‘Die cambrischen u. silurischen Geschiebe Schleswig-Holsteins,’
Archiv fiir Anthrop. u. Geol. Schl.-Holst., vol. i. pt. i. (1895) p. 88.

5 “Mon. Brit. Foss. Brach., vol. iii. (1869) p. 189, pl. xxiv. figs. 23-25 ;.
yol. v. Suppl. Sil. Brach. (1882) p. 159, pl. x. figs. 12-14.

6 «Fragm. Silur.’ (1880) p. 22, pl. xiii. figs. 20-22.

76 MR. F. R. COWPER REED ON THE [Feb. 1897,

nally, the characters of these varieties appear to be identical. The
small subcircular, flattened forms which Davidson figures (op. supra
ut, fig. 25), and which I have also found at Keisley, are probably
only young individuals of the species, In these the median dorsal
fold is more sharply defined posteriorly than in the other forms.
The description of the species is as follows :—Shell longitudinally to
transversely ovate, subglobose. Hinge-line curved. Cardinal angles
rounded. Pedicle-valve the larger, with prominent beak incurved
over the hinge-line; a weak median sinus is present in this valye—
narrow near the beak, but increasing in width and depth anteriorly ;
a slight fold borders it on each side, and in some individuals a faint
median ridge occurs in it. Brachial valve less convex than the
ventral; beak small, and hidden beneath the incurved beak of the
other valve. A low subquadrate fold with steep sides exists in this
valve and corresponds to the sinus in the pedicle-valve ; the fold is
indistinct posteriorly in the adult and old individuals, but strongly
developed on the anterior edge, where a deep sinus borders it on
each side.

The surface of the valves is smooth, or decorated with very
delicate radiating strie (?).

A pair of sbort, subparallel, dental lamellae is seen in the um-
bonal cavity of the pedicle-valve, and a strong muscular impression
lies between them.

- In the brachial valve a short septum exists, extending for about
one-fifth of the length of the valve. The crural plates (seen in the
course of developing one specimen) are triangular, and divided by
a narrow deep median cleft exactly as figured in Hyattella congesta
(Conr.).". The crura themselves are short, as in that species also.
The primary lamelle run forward with a steady divergence of from
25° to 30°, with no outward and only a shght upward curvature.
The points and manner of attachment of these lamelle have not
been seen. They extend forward for more than two-thirds of the
length of the valve, and then are coiled into the spiral cones.
These cones consist of only four or five volutions, and form very
loose coils. Their bases are subparallel to the longitudinal axis __
the shell, and their apices are directed laterally and slightly back-
ward and downward into the pedicle-valve.

The loop has not been satisfactorily or clearly exposed; but it
seems to arise at a point about haifway along the primary lamella,
and to make a very acute angle with them, running backward
with an upward curvature. At the angle where its lateral branches
unite a strong single median process—apparently tubular—is given
off, and rises abruptly in an upward direction to the level of the
primary lamelle. The point of this process is seen as a central dot
between them in grinding down the brachial valve.

millim, millim,
Kength of shell .....cjsc.creeneeeeee see 10 9
Breadth!) 5.) and eh ees: 15 8:5

——e

1 Hall & Clarke, ‘Pal. N. Y.,’ vol. viii. Brach. pt. ii. (1894) p. 61, pl. x1,
figs. 23-28, .

Vol. 53.] FAUNA OF THE KEISLEY LIMESTONE, 77

Affinities.—This species I would assign to the genus Hyattella,
which Hall & Clarke have recently established (Joc. cit.) In ex-
ternal characters H. Portlockiana agrees very closely with Conrad’s
H. congesta from the Clinton Group, and in its internal features the
loose spiral coils, with their few volutions, position, and shape, the
course of the primary lamelle, the shape of the hinge-plate, with
its narrow median cleft and short crura, the deep and striated
pedicle-cavity in the pedicle-valve, with strong short dental plates,
and the loop and process, so far as can be made out, are essentially
similar. The chief points of difference are the presence of the
short median septum in the brachial valve, and the greater length
of the process of the loop.

This species (H. Portlockiana) is found in the Leptena- Limestone
in tolerable abundance.

POLYZOA.
PrILODICTYA COsTELLATA, M‘Coy ?

Prinopictya REcTA, Hall?
These two species are doubtfully recorded from Keisley.

FENESTELLA ASSIMILIS, Lonsdale.
Not very common.

MOLLUSCA.
Cephalopoda.

OrtTHOCERAS cf. SCABRIDUM (Ang.).

Some fragmentary specimens from Keisley resemble this species:
of Angelin’s’ in their cylindrical shape, with a very slow rate of
tapering, in the great distance apart of the septa (7. e. 1 to 14
the diameter of the shell), in the deep cup-shape of the septa, in
the central siphuncle, and, as far as can be seen, in the ornamen-
tation of the surface of the shell.

O. scabridum, in Sweden, is found in the Orthoceras-Limestone.

Foord* mentions that, in addition to O. cf. elongatocinctum:
(Portl.), another species occurs in the Keisley Limestone, and he
may be referring to O. cf. scabridum.

ORTHOCERAS cf. ELONGATOCINCTUM (Portl.).

Foord (Joc. cit.) describes this species from Keisley, where it is the
commonest Orthoceras, and in some parts of the limestone occurs in
abundance almost to the exclusion of other fossils.

? Lindstrom, ‘ Fragm. Silur.’ (1880) p. 4, pl. iv. figs. 6-9 & pl. vii. figs. 8-10.
* Quart. Journ. Geol. Soc. vol. xlvii. (1891) p. 526. i mn

78 MR. F. 8, COWPER REED ON THE [Feb. 1897,

Gasteropoda.

LoxonEMA stTRIATIssimuM, Salter MS. (PI. VI. fig. 6.)

Shell elongate, turriculate, consisting of nine or ten whorls.
Apical angle about 20°. Whorls ventricose, about twice as broad
as long, the successive whorls regularly decreasing in size towards
the apex by one-third of their length and breadth. Upper whorls
constricted just below the suture. The suture-line crosses the axis
of the shell at an angle of about 70°. Surface of shell ornamented
with fine longitudinal curved lines.

There are specimens of this shell from the Kildare Limestone,
and it is one of these in the Jermyn Street Museum which bears
the MS. name L. striatissemum. It was probably given by Salter.
L. sinuosum (Sowerby)? is a closely-allied species, and so is
L. intumescens (Lindstrom),’* but they possess strongly-bent striz
on the whorls. L. dalecaricum (Lindstrém),*’ of the Leptena-
Limestone, has whorls too globose and short to be considered
identical with the Keisley form.

Hotorgra concinna, M‘Coy.

This species is found at Keisley, and is said to be very abundant
at the Chair of Kildare.* There are specimens of it from the latter
locality in Sir R. Griffith’s Collection in the Dublin Museum.

HonopPFA sTRIATELLA, Sowerby.

Casts of this species are not uncommon at Keisley. I have been
unable to assign to it definitely any specimens from Kildare.

CYCLONEMA RUPESTRE, EKichwald.

This species is found at Kildare, and I have seen a portion of a
single shell from Keisley in the Carlisle Museum, where it was
labelled Holopea concinna. It is not recorded from the Leptena-
Limestone, but Schmidt’ gives it as T’rochus rupestris in his list
of fossils from the Lyckholm-bed (Stage F).

CYcLONEMA SULCIFERUM, Hichw.

Of this shell I have seen only one imperfect specimen from |
Keisley. It occurs in the Kildare Limestone, and in the Orthoceras-

‘Limestone of Esthonia.

EvunEMA CaRINATUM, Lindstrom, var.

The only point of difference between a specimen from Keisley
and that figured by Lindstrém * from the Leptena-Limestone is

1 «Sil. Syst.’ pt. i. (1839) p. 619, pl. viii. fig. 15 (Terebra).

2 «Sil. Gastrop., etc. Gotland,’ K. Svensk. Vetensk. Akad, Handl. vol. xix.
(1884) no. 6, p. 148, pl. xv. fig. 6.

8 « Fragm. Silur.’ (1880) p. 14, pl. xv. fig. 19.

4 M‘Coy, ‘Syn. Sil. Foss. Irel.’ Dublin, 1846, p. 18, pl. 1. fig. 10.

5 «Rey. ostbalt. silur. Trilob.,’ pt. i. Mém. Acad. Impér. d. Sci. St. Péters-
‘bourg, ser. 7, vol. xxx. (1881) no. 1, p. 38.

6 Op. jam cit. p. 14, pl. xv. fig. 20.

VOLs52.]| FAUNA OF THE KEISLEY LIMESTONE. 79

that the apical angle is rather larger, giving consequently a broader
and shorter form to the shell. The seven ventricose whorls
furnished with three revolving caring are apparently quite similar
to those in the Dalecarlian individuals.

EVoMPHALUS cf. oBTUSANGULUS, Lindstrom.

There are several small specimens of an Huomphalus in the state
of casts, which may well be compared with Lindstrém’s species
F.. obtusangulus,* but they are not sufficiently well preserved to admit
of any positive statement as to their specific identity. H. obtusangulus
is a Leptena-Limestone species.

EvoMPHALUS NITIDULUS, Lindstrém ?

I have little doubt that the fossil which is here referred with
a query to Lindstrém’s” species from the Leptena-Limestone will
ultimately be found really identical with it. It appears very similar
to Billings’s Straparollus Hippolyta.’

EvoMPHALUS sSuBSULCATUS (His.) ?

There is a portion of a shell in the Carlisle Museum which may
belong to this species, quoted by M‘Coy * as common in the Chair
of Kildare Limestone. The fragment that I have seen is merely
part of a shell coiled in a flat spiral, with several carine running
round the whorls.

PLATYCERAS VERISIMILE, sp.n. (PI. VI. figs. 7,7 a, & 7 6.)

Shell neritiform, transverse, about twice as broad as high; spire
low and short; of three or four whorls rapidly decreasing in size.
Body-whorl very large, twice as broad as high, and nearly three
times as large as the succeeding whorl. Suture only slightly
impressed. Surface of shell ornamented with fine longitudinal lines
which are rather irregular in size and very slightly sigmoidal.

This species much resembles the Swedish form Pl. caniculatum
(Lindstrom),’ but its sutural line is not so deeply impressed nor is
its body-whorl so long. The mouth of the shell is not preserved.
The ornamentation is different from that of Pl. cornutum (Hisinger),°
which it otherwise resembles. ‘The American species Platyostoma
niagarense" appears to show much the same characters.

PLatyceras cf. connuruM, Hisinger.

This very variable species is held to be synonymous with Natica
parva (Sowerby), and with several other British species. Our
specimen resembles most closely the species of Sowerby’s just

* *Fragm. Silur.’ (1880) p. 12, pl. xvii. figs. 19-20.

2 Ibid. p. 12, pl. xv. figs. 24-26.

3 ‘Geol. of Canada: Palzoz. Foss.,’ vol. i. p. 160, fig. 144.

4 ‘Syn. Silur. Foss. Irel.’ (1846) p. 14.

5 Op. gam cit. pl. xvii. figs. 13-16.

° ‘* Lethsea Suecica’ (1837) p. 41, pl. xii. fig. 11 (Pileopsis cornuta).
7 Hall, ‘ Pal. N.Y.,’ vol. ii. (1852) p. 287, pl. 1x. figs, 1 a—v.

80 MR. F. R, COWPER REED ON THE [Feb. 1897,

mentioned. The ornamentation, so far as can be made out, consists
of fine, longitudinal, sigmoidally-curved lines, with some faint con-
tinuous transverse lines running round the whorls, and better marked
near the middle of the whorls.

PLEUROTOMARIA NOTABILIS, Kichwald ?

An internal cast of a Plewrotomaria appears to me to be referable
to this Russian species described and figured by Eichwald.! The
shell itself has not been figured or described, and the casts of
species of Pleurotomaria are always somewhat unsatisfactory and
difficult of identification. Pl. notadbilis occurs in the Borkholm
Limestone.

Movrcuisoni1a, sp.n.? (Pl. VI. figs. 8 & 8 a.)

The cast of a small gasteropod from Keisley appears to belong
to the genus Murchisonia, though some of the tall species of Pleuro-
tomaria are not unlike it. It is a turriculate shell of six convex
whorls, with an apical angle of 30°. Each whorl is very short,
being less than half as long as broad. This gives a peculiar com-
pressed appearance to the shell. The suture-line is almost at right
angles to the axis. A faint, narrow, spiral band can be detected
running round rather below the middle of the whorls. Iam not
acquainted with any species showing the above characters, and
believe that this specimen belongs to a new species. Its length is
7 millim., and across the basal whorl the breadth is 4°5 millim.

Pteropoda.
CoNULARIA, sp.

A solitary specimen of Conularia in the Carlisle Museum has the
following characters:—Shell short, triangular, rapidly tapering to
the apex, with sides converging at an angle of about 50°. Surface
with a median depression, and ornamented with simple, transverse,
parallel raised lines, slightly sinuated in the middle, and more than
their thickness apart. Length=3 millim.; width at front end=
2°5 millim.

Harkness” records Conularia elongata (Portlock*) from the
Keisley Limestone, and this specimen, to which I hesitate to give a
specific name, is thus labelled. The ornamentation is certainly
very similar, though I was not able to distinguish the fine longi-
tudinal lines which Portlock figures. Portlock says of his species
that it is ‘characterized by the very gradual decrease in its
thickness,’ whereas our specimen is characterized by the very rapid
decrease in its thickness, so as to resemble in shape Hall’s species
CO. trentonensis.* For these reasons, I cannot hold that the identifi-

1 * Lethea Rossiea,’ vol. i. (1860-61) p. 1170, pl. xliv. figs. 22 a—d.
2 Quart. Journ. Geol. Soc. vol. xxi. (1865) p. 249.

3 «Rep. Geol. Londonderry’ (1843), p. 393, pl. xxix a. fig. 2.

4 «Pal. N.Y., vol. i. (1847) p. 222, pl. lviii. fig. 4.

Vol. 53.] FAUNA OF THE KEISLEY LIMESTONE. 81

cation of our specimen with C. elongata is correct. It does not
appear to agree with any of Holm’s Swedish species.’

HYoLitHvs TRIANGULARIs ? (Portl.).

Prof. Harkness recorded this species from Keisley, and a speci-
men so labelled is in the Carlisle Museum. I am doubtful as to
the correctness of this identification, for the rate of tapering of this

specimen is more rapid, and, unless we regard it as the broken
- pointed end of the shell, it is a much shorter form than that figured
by Portlock * and in Murchison’s ‘ Siluria.’ *

Lamellibranchiata.

PreRIN#ZA SUBFALCATA, Conrad, var.

Shell obliquely oval, subfalcate, narrow, strongly convex ; umbo
gibbous, acute, projecting above hinge-line. Surface ornamented
with regular, simple, radiating, straight, fine ribs, of which the
anterior ones are slightly curved forward. Anterior ear small,
flat, triangular, sharply marked off from the body of the shell,
striated. Posterior wing not preserved, but apparently as abruptly
defined from the body of the shell as the anterior ear.

millim
Length of shell (obliquely measured) .............+. 10°5
Width of same across middle .............seceeceeeee 70

This shell, which is in the Carlisle Museum, was labelled, appa-
rently by Harkness, as Pterinwa tenuistriata; its shape and
ornamentation are, however, completely different. It differs from
typical specimens of Pt. subfalcata (Conrad) * only by the absence of
the concentric strie. The type-form of the species occurs in the
Upper Ludlow.

Anopontoprsis, sp. (Pl. VI. figs. 9 & 9a.)

Shell small, subcireular, gently convex, most convex near the
beak; hinge-line slightly curved; beak near the anterior end,
directed forward. The beak rises steeply above a small flattened
portion immediately in front of it. No muscular scars or pallial
line visible. Length 4°5 millim.

M‘Coy’s Anodontopsis bulla® appears to bear resemblance to this
Keisley form, but it is with some hesitation that I refer the latter to
the same genus, since it hardly shows sufficient structural features

1 “Sveriges Kambr. Silur. Hyolithide o. Conulariide,’ Sver. Geol. Undersdkn.
ser. C, no. 112 (1893).

2 “Rep. Geol. Londond.’ Mies p. 375, pl. xxviii. A, figs. 3 a-c,

> 5th ed. p. 199, Foss, 41, fig. 2

* M‘Coy, ‘Syst. Descr. Brit. Pal. Foss. (1855) p. 268, pl. i.1, fig. 3,

® Ibid. p. 271, pl. i. x, figs. 11-13.

Q.J.G.8. No. 209. G

82 _ MR. F. R. COWPER REED ON THE [Feb..1897,

to allow of one’s feeling sure of its affinities. Murchison’s species
Incina ? Hisingeri,' from Gotland, also bears comparison with our
form.

MoptoLorsis ?, sp.

Harkness recorded Modiolopsis Nerer (Munster) fae Keisley.’
There is a specimen in the Woodwardian Museum with that name
attached to it, but it is a mere fragment, and, in addition to feeling
sure that this identification is erroneous, I have grave doubts even
about the genus to which it should be referred. The anterior
portion of a left (?) valve, probably of a circular shape when perfect,
with a small inconspicuous beak some distance from the anterior (?)
border of the shell, with the surface ornamented with concentric
strie-——these are all the characters visible, and they are quite
inadequate for identification.

ECHINODERMATA.
Cystidea.

SPHHRONITES PYRIFORMIS (Forbes).

Forbes describes this species as Caryocystites pyriformis® from
the Chair of Kildare, but none of his specimens showed the ar-
rangement of the.plates. Our specimen, though imperfect, shows
distinctly five tiers of large pentagonal or hexagonal plates some-
what irregularly arranged, but it is too incomplete to allow of any
certainty as to the number or position of the plates in each tier.
There are, however, five basal plates to be made out, and these with
three lateral tiers and the summit-plates compose the test. The
length of our specimen is about 18 millim.

The species has also been recorded from Rhiwlas.*

Crinoidea.

Only portions of the stems of various crinoids ° have so far been
found in the Keisley Limestone. Consequently, it is impossible with
this unsatisfactory material to determine the genera and species;
as there are, however, several well-marked types of stems which

1 Quart. Journ. Geol. Soc. vol. iii. (1847) p. 24, woodcut; F. Romer,
‘Leth. Errat.,’ p. 87, pl. vi. fig. 7, & p. 101, pl. viii. fig. 2 (Palzont. Abhandl,
ii. 1885).
ne Be Journ. Geol. Soc. vol. xxi. (1865) p. 249.

3 Mem. Geol. Surv. vol. ii. pt. 11. (1848) p. 515, pl. xxi. fig. 1.

4 Ibid. vol. iii. 2nd ed. (1881) p. 476.

5 Holm mentions crinoidal remains from the JLeptena-Limestone, Sver.
Geol. Undersdkn., ser. c, no. 115, pp. 14, 15 (Stockholm, 1890).

Vol. 53.] FAUNA OF THE KEISLEY LIMESTONE. 83

may at some future date be found associated with the calices, a brief
description of them will be useful.

One type (a) consists of thin circular ossicles furnished with a
strong rounded projecting ridge on the periphery, occupying rather
more than one-third of the width.

Another common type (3) is composed of large, plain, smooth
ossicles, unornamented, and all of equal size, forming a regular,
smooth, cylindrical column.

Yet another type (vy) is quadrangular in section, and composed
of alternating thick and thin ossicles with a large central canal.

A fourth type (6) consists of circular ossicles, with a thickness of
about one-fourth of the diameter of the stem, and all of the same
size. A narrow, smooth, marginal ring surrounds the front edge,
and a series of fine concentric lines with a single median circlet of
tubercles adorn the rest of the periphery. There is a large central
canal, with the margins radially striated.

Another type (e) is composed of circular thick ossicles of equal
size, with a rounded periphery ornamented with eight or nine
longitudinally-elongated tubercles. The central canal is very -
small,

A sixth type (2) of stem shows a pentagonal section with a
central canal of about one-fourth the diameter of the stem. And
finally there is another type (), which has a circular section, and
is composed of thin ossicles ornamented with encircling threads
swelling into irregularly-disposed low tubercles.

ACTINOZOA.

SrREPTELASMA EUROPZUM, F. Romer.

This species seems to be the commonest coral at Keisley. It
occurs also in the Borkholm ? and Lyckholm zones,? in the Sadewitz
drift-pebbles,* and is common in the Craighead Limestone.*

HALyYSITES CATENULARIA, L.

_ In England this species ranges from the Bala to the Silurian. I
have seen only one specimen from Keisley. It occurs also in the
Kildare Limestone, in the Leptcena-Limestone, and in the Lyck-
holm zone.° |

1 ‘W. Weissermel, ‘Die Korallen d. Silurgesch. Ostpreuss.,’ Zeitschr. d.
Deutsch. geol. Gesellsch. vol. xlvi. (1894) p. 580.

* Fr. Schmidt, ‘Rey. d. ostbalt. Silur. ‘Trilob.,’ pt. i Mém. Acad. Imp. des
Sci. St. Pétersbourg, ser. 7, vol. xxx. (1881) no. 1, p. 38.

° F. Romer, ‘ Die foss. Fauna d. Silur. diluv. Gesch. v. Sadewitz, Breslau,
1861, p. 16, pl. iv. fig. 1.
: eee & Etheridge, ‘Mon. Silur. Foss. Girvan,’ 1878, p. 76, pl. vi.

BL B.

55 Weissermel, op. supra cit. p. 661.

84 MR, F. R. COWPER REED ON THE [Feb. 1897,

He tiouires pusra, Schmidt ?

As far as one can judge from the external aspect, size, and
arrangement of the corallites in a small fragment of a corallum,
this species occurs at Keisley. Schmidt’ describes it from the
Lyckholm Beds, Lindstrom?” from the Leptena-Limestone, F. Romer*®
from the Sadewitz pebbles,* and Weissermel* from those of Rosen-
berg.

Srenopora FrBRosa, Goldf.
This species is of common occurrence at Keisley and Kildare.

FavosiTEs ALVEOLARIS, Goldf., pars.

The Geological Survey of Ireland record this species from the
Chair of Kildare, and it may be identical with the variety of
the allied #. aspera said by Schmidt to occur in the Borkholm
zone. J’, aspera’ has smaller corallites with greater irregularity of
size.

Prasopora Gray, Nich. & Eth.

Prof. H. A. Nicholson, to whom I am indebted for kind assistance
in this group of organisms, informs me that he has found this
species at Keisley. In his work ‘ Paleozoic Tabulate Corals,’ he-
says (p. 327): ‘The only known species of Prasopora [i.e. Pr.
Graye]| occurs commonly in the Craighead Limestone (Lower
Silurian) of Craighead, near Girvan, Ayrshire.’

Note.—In addition to the above-mentioned species, there are
several indeterminable zaphrentoid corals and monticuliporoids in
the Keisley Limestone. Harkness recorded WNebulipora lens from
this rock, but the specimen thus labelled in the Carlisle Museum is
very indistinct and doubtful.

1 «Untersuch. ib. d. Silur. Form. Ehstland, etc.’ (1858) p. 228.
2 «Fragm. Silur.’ (1880) p. 32, pl i. figs. 1-4.
3 «Die foss. Fauna d. Silur. diluy. Gesch. vy. Sadewitz’ (1861), p. 26, pl. iv.
fig. 5.
e; Zeitschr. d. Deutsch. geol. Gesellsch. vol. xlvi. (1894) p. 666 & pl. liii. fig. 4.
5 Edwards & Haime, ‘ Brit. Foss. Corals,’ Monogr. Pal. Soc. (1850-1855):
p. 257, pl. lx. figs. 3 & 3a.

Vol. 53. ]

FAUNA OF THE KEISLEY LIMESTONE.

List oF Fossi~s FROM THE KEIsSLEY LIMESTONE

85

(showing also the species occurring in the Kildare

Limestone, etc.).

GENERA AND SPECIEs. 2 5 = s
SB
= 38.3
als
“ia
TRILOBITA,
Agnostus cf. galba, Billings ............+0+ cholerae etiite at lata
WeATUPY LE CMOWULOSUS) TI, SPs \cacenccacesaenacnravesniwananseacu
RUFESUGS WNSCUUPLUS, MCOY ....0.cancconasecncacacanceeecocasns *
Remopleurides Colbi, Portlock. .-.cwavwrecevseeesececucesone
- longicostatus, Portlock .........2.:seeseeees *
Ciphoniscus socialis, Salter ......--v0vewservescveverarsoeeceees *
Calymene Blumenbachi, var. Caractact, Salter ...........-
Homalonotus ? punctillosus, Tornquist .......cs.s.sesseeees %.) x
LINED IES DE OQUTOTT UDR IS TU) Wi eRe Ee CARPAL CCR EP EO ee meee *
5 7 var. brevicapitatus ..... Boot aes *
5 iy Var. LONGICAPULALUS ...ccseeesecececeeees
Ma tre Olt: aciava us saae de edawanaewndeeeebeanaaeess« * | x
PERE E77. WiOLDOLEI: cccanaisde oaenes bade see loesiioawoses ? *
PR CCCUS ETON kr, sin aivante ewe cnenstaeteeee Mi cadebePeanias em ober
PAO UCEL IES BI)u) We shetaitonidenarceeacaeomeecacsosuausovs dence
» 8p. (hypostome) ........0000 iictda fie atest esate ela %
Cheirurus bimucronatus, Murchison. .........+.sceecesseeees *
re cancrurus, Salter ......csccees Wiig ete A all yeelive
9 ECISICYONSIS, SPs Was a toatamwaeabueeenwceeesass cee st *
45 GF. glaber, Angelimy ..:...cvtertctseswasieennevede tases Re eal,
Are ise ef. clavifrons, Dalmay « sacrnecterntas tecdeevecscnse e
” (Pseudospherexochus) conformis, Angelin x | x
A % subqguadratus, sp. n....| ?
? Spherocoryphe granulata, Angelin ..........c0:cscceseeeee ? | x
Spherexochus mirus, Beyrich .......cssecsessccosscessevesvees * | x
sis LATUTUGATUS, BP Ts - oc .cssscesecasacacssscersee %
Staurocephalus Murchisoni, Barrande ...........sseeseeeee *
| Acidaspis convexd, SP. D. — .s.seecevecssevcereoeeere dla
t SFTP cisco th htselalevolatlatetartattoateetestaletaw'stelciercreloteetelecivdo u'
Lichas Pee NICOL «iis ewweianicieerniewetnvrereatatdlotstewerec'oeie'o ost ge’ %
at OL ULEQUUS) Dy. SPs» avieniawrtiawe'e erate aactencl retaliate tubes a safe ?
of | Cillurceps,, PUGS MIS, « «snoneeenteveccevedecncueues #
jx COMSOTINISMAT TE cravecers nieces saatdefsletitardderaevaeniatas owe | ¥
5 33 VEL ACISICYCNSIS » -eraaeetaatstentedeeviesieodoeee
fa LLULENMOUS EOMLOC Mn sainecenwedaastoviecdeseseuteccdeaes *
5h MOLGLUS NE OO Yr» rot veraciaautonesiteriadizeaweteeatddvedaed’s * | %
Cyphaspis ? Harknessi, sp. Vi. .......ccseeeseserecceeeveeccenes
» (Tornquistia) Nicholsont, sp. D. ......ceeoseeseses *
| Phillipsinella parabola, Barrande .........ccseceecereesecees
Harpes Wegelint, Angelin : ....2..-ccsccisedscceceeddssescesces * | *
1? 5, costatus, Angelin§ .....cccscceeese Biddddlstaw ee vedetddeee Soe Hae
3 OD i O airweartnsdndattanssdddardivicederedcaaidadeasdatasede

Stage F,
——>
ae
Soa|So
a als
SN/ON
a lH
* | *
eee *
es *%
* | *
?
* | %

86

. MR. F. R. COWPER REED ON THE

List or Fossits (continued).

[Feb. 1897;

2 spp.
Strophomena

Rafmesquina

2?

99

?

” 9
° ”

”

Orbiculoidea,

| ? Lingula, sp.

GENERA AND SPECIES.

OstTRACODA,

Pritt, WE CONG, SAUEOL) apes cewek onsiosea einer nomeeeacencs
Cythere Wrightiamd, JONES ......+0...0ncassssapassanenedeeass

BRACHIOPODA.

Orthis calligramma, Dalman ...........00sseereeeeeeeseeees

VAL. coccccccecevcccsrecccncccceccscesees

:. Actonia, Siiceebiyey anicersesias aces es wees
: vespertilio, SOWGEDYs.ce-desiecpah seeds rates beth peer renee
», (Bilobites) biloba, Linné ..... ac Sodee eet ht aes
» (Platystrophia) biforata, Schlotheim ...............
(Dalmanella) testudinaria, Dalman ...............

3 ) ef. conferta, Lindstroniw “cseecavene
53 ) cl argented, Misinger i... 0. j0.c.0s-0
4 ) elegantula, Dalian, ...05....+ +0002

ae (Heters7this) GILETNATE, BOWEIDY .. sisscecedeecerss
? ,, (Dénorthis) flabellulum, RD WEEDY | pacrry reer eoomntee
3» (?'Hebertella) Keisleyensis, 8p, 1. sevirseeers-ceccdouss

IN OOED av sxnvciphesrneccaceanes deemue sadeseosnees
antiquata, SOWELDY.....rrcrecpprosresstscsoness
corriugatella, Davidson ...........+ssssersceees

Leptena Phagnuord Gs, WV UCKONS «i. heinses- roy aneurin bsinceersoee

CLPANSG, SOWCLDY. presence coceseharesderses aamue
DELCOLMED,.-.» sss 49a dein nla pace Lda y Poa eemn cise
| VAL. Undata, MOY sien acc -n-cceney

Plectambonites guinguecostata, M‘ Coy » eas hedetihee tina beint

Sehmidt, Tornquist, .ccrecpecres= 20s ek vee -
transversalis, Wahlenberg -. 4. sec. .san oo

Atrypa qmargimalis, Walman s.::esesrseensaden sores s-nrerear=
wo CLpause. Miia sino Seessec rye re rprerscermaces side e

WAT Pie ocnareteoeerecucrsepesceacereesaehes

Atrypina SUMGMS AST, seep eccaseacereoesyecec pony asbibied
| Christiania -cenuicincta, M‘OOY. ppres-nrcrrecersscssercssccsse
| Streptis monilifera, M‘ Coy PEG rab rear ee wine abeiimebie hii. 5
Triplecia:instlargs, WichWald ..o.ccsermeseceseanveis es seasvee si
Rhynchotrema cf. dentatwm, Hall ..... eee reane ar seecs wee
Samm O PREG GIS, SD. Ws ccercrnsescceecpnesenrrocas (sb datec es
| Camerella ? Thomsoni, Davidson ......0...s.ceeeceeececeeee
Hyatiella Portlockiana, Davidson ........ oh ebignimienpels be
| DaYiG PENTAGONGMS, BP, Ne on cavanenenscnenentasaesenns ed oeeden
| Obolella ef. nitens, Hisinger .........ss.seseeeesseeseereeeeee

22 STRING, erate eee A ere el emeriksnnireier Asner

POCF OS eeerestsresselOCFESOSOHSHTESHOHEOETESESHSL OSLO

Kildare
Limestone.

Leptena-
Limestone.

|

2 OK OK

Stage F.
——_
= ig
So a1oo
aesjaad
M4 S| 9
BN/ON
A iA
*
* *
*
* *
* *
*

Wak 533] FAUNA OF THE KEISLEY LIMESTONE. 87 *

List oF Fosstts (continued).

Stage F,
SS SS
o/1 60/8 |4
GENERA AND SPECIES. £8 S 8le6iec
SES ele Sie
4 eS slSNiEN
ay gars |
Potyzoa.
Ptilodictya costellata, M*Coy ? ...........sescssseeceereneees Pid aa is it
a TECHIE TERRY. RUS DIRS AROSE. *
Fenestella assimilis, Lonsdale .........0.s0.2cs-sescenesscecees x
Mou.vsca.
Orthoceras cf. elongatocinctum, Portlock ...........-..066
ek scabridum,; Ampeliny 225.5 Jididewodss--d0tvesae
Loxonema striatissimum, Salter MS. .........c20cesceeeeeees *
EPAPER COUCHIIG ICON, opin ckn sis ca nddne nd adesinsiisaaaee <n *
PU SERULOLIIG OO WCCOY akan cpoamineecesncsscanen
Cyelonema rupestre, Wichwald ..2......-..0s0se--seecceeeee- 5 od oem lle ae a
BE sulciferum, Hichwald © ..........2..2ssesceeeesees *
Eunema carinatwm, Lindstrom, var. ..........e0eeeceseeeees an Os:
Euomphalus cf. obtusangulus, Lindstrom ............0606-- <<a
aes subsulcatus, Hisinger ....eccccseesesaccenese x | *
? Ss SGTONNTES: WONGSETOINS > 2.02) cehediccs cnetee nee *
Platyceras verisimile, Sp. MT. ....cscsccececevendorcececesceees
- ef. cornutum, Hisinger .....0.ccscss0ssbecnces--
? Pleurotomaria notabilis, Hichwald ..............seeeeeeee: ei haath,
MU hASONA, SP. ? o.0us-nesceseeceenees iain de adeae wa ac ee
EEE IEIEAENES Celene ogre es oaoceedanuy asasbtacegeoastionads ss “
? Hyolithus triangularis, Portlock ...........cscececeeceneees
Pterinea subfalcata, Conrad, var. .........ccceeecessececeees
ECU DSES: SD. Vows ctiwnndes ds «aaranae «inde sie baanbeieh bngaa fans
ULCERS Gg ae ee arene ree Meee ee
EcHINODERMATA.
Spheronites pyriformis, Forbes .........cessseeeeees Peto x
GUTOR VER” (11 ho oe ne a ae er
ACTINOZOA.
Streptelasma ewropewm, Romer .........cecseceeeenececeeeee: Seo Wael yiyas PY 9
Halysites catentlari@, Linn | ....secncecolsnecensacscdesdess: 36h EL Gooe ol +E
& Heliplites Cupid, SCOMIGE. ....... .ncracearsascatssancesaseaces eet Or an oe ee:
CETIPON® ITM, COMO TIBS ...<..c0:0s02-ueeenroodecnceacscecs x
Favosites alveolaris, Goldfuss, pars .....csccseceseneceeeees *
Prasopora Graye, Nicholson & Etheridge ..............-

& NCP eae PTI NICO isms «Su gasdicvinwesn'edtbasinwescennnoa>

88 MR. F. R. COWPER REED ON THE [Feb. 1897,

GenERAL REMARKS ON THE FAUNA OF THE KBEISLEY LIMESTONE.

I. Trrtosrra.—The Trilobita are unmistakably the predominant
members of the assemblage of organisms which we meet with in
the Keisley Limestone. Not only in the number and variety of the
genera and species do they far exceed other groups, but also in the
number of individuals. Yet all the genera are not equal in this
latter respect, nor are the species. The J//eni are the most common
of all the trilobites, and large slabs covered with the head-shields
and pygidia of I. Bowmani and its varieties are of frequent occur-
rence. J. galeatus is the next most common species of Illenus,
while J. Remeri, I. fallax, and J. cecus are very rare.

Next in order of abundance come the genera of Cheiruride, and
in species and individuals they hold the same place. The species
of Pseudospherexochus and of Spherexochus are represented by
numerous individuals. The genus Zichas has at least six species
belonging to it in this rock, but the individuals are not numerous.
Cyphoniscus socialis is fairly abundant. From the failure of many
observers and collectors to find such trilobites as Staurocephalus
Murchison, of which I have myself collected at least a dozen
specimens in a few hours, I believe the occurrence of such forms
is sporadic or limited to special bands in the rock. It should be
remembered that the great majority of the fossils recorded have
been collected from loose blocks in the adjacent stone walls, or
hammered out of detached masses lying on the surface of the
ground. Many of those which I found were obtained from the
remains of an‘old lime-kiln close to the large quarry, but others
were chipped out of the outcropping solid rock.

The peculiar features of the trilobitic fauna are :—(1) The absence
of the genera Phacops and Trinucleus. Both these genera are 80
abundant in the Bala rocks of all areas, and are represented by
species so characteristic, that their entire absence is very striking.
In the Staurocephalus-Limestone and Ashgill Shales, as well as
in the underlying Middle Bala, we find them making a marked
feature in the fauna. The genera Trinucleus and Phacops are
practically absent from the Chair of Kildare Limestone’ and the
Leptena-Limestone. Trinucleus is very rare in the Russian Stage F,”
and till recently was thought not to occur there. (2) The occurrence
of certain peculiar genera of very limited range in time and space,
as, for example, Cyphoniscus and Tiresias. (3) The occurrence of
many peculiar species limited either entirely to this Keisley bed, or
to it and the Chair of Kildare Limestone, or to both these beds and
the Leptena-Limestone of Dalecarlia, or to the Keisley and Dale-
carlian beds, or to one of these beds and Stage F of the East Baltic
provinces of Russia.

1 Quite recently Mr. OC. I. Gardiner, F.G.S., has shown me an eye of a
Phacopsand a fragment of a Trinucleus—possibly Tr. seticornis (His.)—from the
Kildare Limestone ; but these are the only specimens I know.

2 Fr. Schmidt, ‘Rev. ostbalt. Silur. Trilob., pt. iv. Mém. Acad. Imp. des
Sci. St. Pétersbourg, ser. 7, vol. xlii. (1894) no. 5, p. 71.

Vol. 53.] FAUNA OF THE KEISLEY LIMESTONE. 89

It will be seen on examining the list of fossils tabulated on p. 85
that, out of the total number of 40 species of trilobites in the
Keisley Limestone, 20 are definitely known to occur in the Kildare
Limestone, and 6 others are doubtfully recorded.

The following species also, so far as is known, are absolutely
peculiar to these two limestones :—Cheirurus keisleyensis, Ch. can-
crurus, Spherexochus latirugatus, Lichas bulbiceps, Tiresias insculptus,
Cyphaspis (Tornquistia) Nicholsoni, and Cyphoniscus socials.

In the Leptena-Limestone 10 or perhaps 12 of the Keisley
species are found, and in the Borkholm and Lyckholm zones 3 (or 4)
and 6 have respectively been recorded. Only a very poor list of the
fauna of the Borkholm zone is obtainable,’ or probably the number
of common species would have to be increased. Moreover, if we
take into account the closely-allied but not identical species of
these beds, the similarity of the trilobitic faunas is still more marked.
Thus Cheirurus bimucronatus and Ch. keisleyensis are allied to
Ch. insignis and Ch. speciosus of the Leptena-Limestone; Ch.
(Ps.) subquadratus to Ch. (Ps.) Remert of the Borkholm and
Lyckholm zones; Lichas bifurcatus to L. margaritifer of the
Leptena-Limestone and Borkholm zone; <Acidaspis convexa to
A. evoluta of the Leptena-Limestone; and Jilenus Bowmani to
I. Iinnarssoni, of the Leptena-Limestone and the Borkholm and
Lyckholm zones.’

The occurrence of many peculiar species of trilobites is very
noticeable. Cheirurus (Pseudospherexochus) conformis occurs in the
above-mentioned beds in each area, and it might well be taken as
the zone-fossil of this horizon.

The following species which are found at Keisley also are markedly
characteristic of, or limited to, the Leptena-Limestone, and therefore
deserve special notice :—Cheirurus glaber, Ch. (Pseudospherexochus)
conformis, Spherocoryphe granulata (?Keisley), Harpes Wegelint,
H. costatus (? Keisley), Homalonotus? punctillosus, Illenus fallax,
and I. Roemer.

The following species have been so far found only at Keisley ;
although two of them are doubtfully recorded from Kildare :—

Cheirurus (Pseudospherexochus) subquadratus (? Kildare), Lichas
bifurcatus (? Kildare), Cyphaspis? Harknessi, Ampya binodulosus,
Acidaspis convexa, and Illenus galeatus.

Turning now to the question of the degree of relationship of the
trilobitic fauna of Keisley to that of the Middle and Upper Bala of
Great Britain, we find the following species occurring in Middle
Bala rocks :—COheirurus bimucronatus, Ch. clavifrons, Dalm.?,

1 Schmidt, ‘ Rev. ostbalt. Silur. Trilob., pt. i. Mém. Acad. Imp. des Sci.
St. Pétersbourg, ser. 7, vol. xxx. (1881) no. 1, p. 88; and Quart. Journ. Geol.
Soc. vol. xxxvili. (1882) p. 514.

? Several of the Kildare trilobites, not hitherto found at Keisley, occur in
Stage F of the Baltic provinces, thus linking these widely-separated beds more
closely together; see S. H. Reynolds & ©. I. Gardiner on ‘The Kildare
Inlier,’ Quart. Journ. Geol. Soc, vol. lii. (1896) p. 587.

90 _ MR. F. R. COWPER REED ON THE [Feb. 1897,

Calymene Blumenbachi, var, Caractaci, Sphceerexochus mirus, Ilcenus
Bowman, Lichas laxatus. .

In the Upper Bala beds the following Keisley species are
found :—Cheirurus bimucronatus, Ch. clavifrons, (?) Spheereaochus
mirus, Lichas laxatus, Illenus Bowmani, *Remopleurides longi-
costatus, *Phillipsinella parabola, Staurocephalus Murchisoni, and
Calymene Blumenbachi.

Of these the two species marked * are in Britain known only
in the Upper Bala (excepting, of course the Kildare and Keisley
Limestones). Ch. bumucronatus, Sph. mirus, C. Blumenbachi,
and St. Murchisont pass up into the Silurian. Lichas hibernicus,
curiously enough, occurs elsewhere only in the Craighead Lime-
stone of Scotland. J. Bowmani and Sph. mirus also occur in the.
Scottish Lower Bala.’

Thus, of the 10 species found in other British rocks, 3 occur in
the Lower Bala, 6 in the Middle Bala, 9 in the Upper Bala, and 4
pass up into the Silurian. But in spite of this apparent great
resemblance to the Upper Bala, we must remember that the absence.
of all species of Zrinucleus and Phacops, especially Tr. seticornis
and Ph. eucentra, characteristic forms of the Upper Bala,” marks
an important difference.

Summing up, we obtain the following percentage results with
respect to the species of trilobites from Keisley :—

(i) 50 °/, occur in the Kildare Limestone.
(ai) 25 °/, occur in the Leptena-Limestone.
(iii) 25 °/, occur in British Bala or Silurian beds, and of these
about 99 °/, occur in Upper Bala beds.
(iv) Over 70 °/, occur in no other British bed.
(v) About 16 °/, are peculiar to the Keisley Limestone.

The peculiarity of the trilobitic fauna of this bed is thus plainly
shown.

II. Ostracopa.—Both the Keisley species occur at Kildare, and
these are the only two localities in which one form (Cythere ©
Wrightiana) is known to occur, while Primitia M‘Coyi, the other
species, is known elsewhere from the limestone of Aldeans on the
Stinchar River.’

III. Bracuroropa.—The foregoing list of the fossils of the
Keisley Limestone shows (p. 86) that out of the 37 species of
brachiopoda, 19—or over 50 °/,—are also found at Kildare, and
several others probably occur. In the Leptena-Limestone * 12 of

1 Nicholson & Etheridge, ‘Mon. Silur. Foss. Girv.’ 1879; Lapworth, Quart.
Journ. Geol. Soc. vol. xxxviii. (1882) p. 537.

2 Marr & Roberts, Quart. Journ. Geol. Soe. vol. xli. (1885) p. 476.

3 Ann. Mag. Nat. Hist. ser. 4, vol. ii. (1868) p. 56.

* In the case of the Leptena-Limestone I have made use of the specimens in
the Woodwardian Museum, Tornquist’s list in ‘ Ofvers. 6. Bergbygn. in Siljans.
i Dal.’ p. 26, Sveriges Geol. Undersokn. ser. c, no. 57, and the ‘ List of the
Fossil Faunas of Sweden,’ published by the Stockholm Museum in 1888.

Vol. 53.] FAUNA OF THE KEISLEY LIMESTONE. 91

the Keisley species, or over 30 °/, of the whole number of Keisley
brachiopoda, have been recognized.

Schmidt mentions only 11 species of brachiopoda from the
Lyckholm zone,’ but of these 5 occur at Keisley. Out of the 10
species mentioned by him (loc. cit.) from the Borkholm zone, 4
occur at Keisley. Other species allied to British forms are recorded
by him from these rocks. Thus we see that there is a considerable
degree of similarity in the brachiopodal faunas.

Atrypa expansa and Orthis conferta appear confined to this
horizon as represented at Keisley, the Chair of Kildare, Dalecarlia,
and Western Russia. Plectambonites Schmidt is highly characteristic
of it, though also known from the TZrinucleus-shales of Sweden,
while Hyattella Portlockiana has elsewhere been recorded only
from ‘the Upper Llandeilo’ of Balcletchie, Girvan.’ Streptis
monilifera, apart from Kildare and Keisley, is mentioned by David-
son only from the ‘Middle Llandovery’ of Woodland Point,*
Girvan.

Three species are peculiar to the Keisley Limestone :—Orthis
keisleyensis, Syntrophia affinis, and Atrypina similis.

The commonest species of brachiopoda at Keisley are Atrypa
expansa (and its varieties), Strophomena corrugatella, and Christi-
ania tenurcincia.

The following Keisley species are found also in the Middle Bala
of England, Wales, and Scotland :—

Orthis callgramma, O. Actome, O. biforata, O. biloba, O. alternata,
O. elegantula, O. flabellulum, O. testudimaria, O. vespertilio, Triplecia
insularis, Strophomena antiquata, Str. corrugatella, Rafinesquina
deltoidea, R. expansa, Leptena rhomboidalis, Christiania tenuicincta,
Plectambonites transversalis, Pl. quinquecostata, (?) Camerella ?
Thomsoni.

Thus over 50 °/, of the Keisley species occur in the Middle Bala.

Of the species occurring in the Upper Bala (2. e. the beds above
and including the Staurocephalus-Limestone) it is difficult to draw
up a satisfactory list, as the fossils have been by no means well
investigated. From lists given by Mr. Marr and others* and from
specimens at Cambridge we see that the following Keisley forms
occur in the Upper Bala:—Orthis Actonie, O. biforata, O. calh-
gramma, O. elegantula, O. testudinaria, O. vespertilio, Christiania
tenurcincta, Leptena rhomboidalis, Plectambonates quinquecostata.

This list is, I believe, much too short, and represents therefore
imperfectly the degree of affinity of the brachiopodal faunas.

1 ‘Rey. ostbalt. Silur. Trilob.,’ pt. i. Mém. Acad. Imp. des Sci. St. Pétersbourg,
ser. 7, vol. xxx. (1881) no. 1, p. 88; and Quart. Journ, Geol. Soe. vol. xxxviil.
(1882) p. 514.

? Davidson, ‘ Mon. Brit. Foss. Brach.’ vol. v. (1882-84), Sil. Suppl. p. 159.

3 Ibid. p. 147.

4 Quart. Journ. Geol. Soc. vol. xxxiv. (1878) p. 871, vol. xli. (1885) p. 476,
vol, xlvii. (1891) p. 500; Geol. Mag. 1892, p. 97.

92 MR. F. R. COWPER REED ON THE [ Feb. 1397,

A very considerable number are found in British Silurian beds.

The following is a list of these species :—

Orthis Actoniw, O. brferata, O. biloba, O. elegantula, O. call-
gramma, O. testudinaria, O. vesperitho, Strophomena antiquata,
Sir. corrugatella, Rafinesquina expansa, Plectambonites transversalis,
Pl. quinquecostata, Leptena rhomboidalis, Triplecia insularis,
Streptis monilifera, and Atrypa marginalis.

Thus 16 species, or over 44 °/,, occur in the Silurian. But none
of these are characteristically Silurian forms,’ and all of them are
known from Bala Beds. Owing, therefore, to their long range, they
are of comparatively little zonal importance, and cannot justly be
used in support of the argument for the Silurian facies of the fauna.
It is also specially noteworthy that such typically Silurian genera
as Stricklandima and Pentamerus (and its subgenera or allied
genera) are conspicuous by their absence. There are, moreover, no
species of Spzrifer such as we should expect to find in Silurian strata.

In the Leptena-Limestone, indeed, Meristella? crassa is found,
but this species marks the conglomerate at the top of the Ashgill
Shales in Britain, and this bed is on the border-line between the
Silurian and Ordovician.

On the whole we must therefore say that the brachiopoda of the
Keisley Limestone are an assemblage of species of a Middle and
Upper Ordovician stamp, but that this assemblage possesses a
certain uniqueness which can be most closely paralleled by that of
the Kildare and Leptena-Limestones, as in the case of the trilobitie
fauna.

IV. Potyzoa.—Members of this group appear very rare at
Keisley, whereas at Kildare and in the Dalecarlian and Russian
assumed equivalent formations they are very common. In fact, the
Leptena-Limestone has the alternative name ‘ Fenestellenkalk,” ’
and a long list of polyzoa is known from Stage F of Schmidt.

All the Keisley polyzoa that I have seen are very imperfect
and fragmentary specimens ; all the species are doubtfully identified,
but two of these (Ptilodictya recta and Fenestella assimilis) occur
in the Kildare Limestone, and the third (Pt. costellaia) is a Bala
form. There is no Silurian species among them. Not one of the
three species is recorded from the Leptena-Limestone or Stage F
except Pt. costellata, which occurs in the Borkholm zone.

V. Motivsca.—Of the mollusca the cephalopoda are by far the
most abundant group in the Keisley Limestone, but there appear to
be only the two species of Orthoceras as the representatives of the
group. Neither of these throw any light on the horizon of the
limestone.

The gasteropoda are represented by a dozen or more species
belonging to 9 genera, but they are by no means common. The
most abundant form is Loxonema striatissimum, which shows
close affinity with Silurian species. The only other species
suggesting Silurian affinity is the form compared with Hisinger’s

1 Except Atrypa marginalis and Orthis biloba.
* Remelé, Zeitschr. d. Deutsch. gecl. Gesellsch. vol. xxxii. (1880) p. 645, &
vol. xxxiv. (1882) p. 651.

”

Moll 53.1 FAUNA OF THE KEISLEY LIMESTONE. 93

Platyceras cornutum. Of the others, Holopea concinna and H. stria-
tella are typically Bala forms.

Loxonema striatissemum, Huomphalus subsulcatus, Holopea con-
cinna, Cyclonema rupestre, and C. sulciferum are found also in.
the Kildare Limestone. Lowonema striatissimum is confined to the
Keisley and Kildare Limestones. Hunema carinatum, Euomphalus
obtusangulus, and EH. nitidulus are Leptcna-Limestone species.
Cyclonema rupestre and Plewrotomaria notabilis occur in Stage F
of the Baltic provinces of Russia.

We thus see that the gasteropoda of the Keisley Limestone
support the conclusions derived from a study of the brachiopoda
and crustacea as regards the affinities of the fauna.

The pteropoda and lamellibranchiata are too indefinite to help us.

VI. Ecuinopermata.—The only determinable form is a species:
(Spheronites pyriformis) which occurs at Kildare and in the Upper
Bala of Rhiwlas. It is also noticeable that this genus is particularly
abundant in the Leptena-Limestone, being there represented by 4
species.’

VII. Acrtnozoa.—Of the Actinozoa Streptelasma europeum and
Stenopora fibrosa, with some indeterminable zaphrentoid corals, are
the commonest forms at Keisley. But corals are decidedly scarce.

Three species—Halysites catenularia, Stenopora fibrosa, and
Favosites alveolaris—oceur at Kildare.

Halysites catenularva and Heliolites dubia are found in the
Leptena-Limestone and in the Lyckholm zone, with the addition
of Streptelasma europeum, which also occurs in the Borkholm zone..

In Great Britain Halysites catenularia ranges from the Llandeilo
formation to the Ludlow, Stenopora fibrosa occurs all through the
Bala, and Streptelasma europewm and Prasopora Graye are found
in the Craighead Limestone of Llandeilo age.

PALMONTOLOGICAL EVIDENCE OF THE AGE OF THE Ketstny Limestone.

After removing from the list of fossils all those species which are
either peculiar to the Keisley Limestone, or are found in no other
bed in the British Isles save the Chair of Kildare Limestone, and
in addition all the doubtful species, we find that there are 16 which
occur in the Lower Bala beds, 28 in the Middle Bala, 20 in the
Upper Bala, and 21 in the Silurian. But, as the following list
shows, some of these are species with a great vertical range, and
therefore ought to be left out of the argument. After their
removal we find that there are 8 or 9 characteristically Middle Bala
species, 3 or 4 Upper Bala species, and 3 Silurian species. <A
mistake against which we must guard ourselves is to lay too little
stress on the occurrence of some species belonging to the fauna of a
bed which is poor in organic remains, or which has been insuffi-
ciently worked out from a palzontological point of view. We may,
I think, safely consider that the Middle Bala and most of the
Silurian have had their organic contents investigated very fully,.

1 «List of the Fossil Faunasof Sweden. I.—Cambrian and Lower Silurian,”
Stockholm, 1888.

94 MR. F. R. COWPER REED ON THE [ Feb. 1897,

but with respect to the Upper Bala we cannot say the same, for the
fossils so far collected are both few in numbers and poorly preserved,
and the fauna requires much more working out, Thus we must
attach more importance to the occurrence of a few typical Upper
Bala forms than their mere number alone would seem to justify.

List or Kerstty Limestone Fossins ocCURRING IN OTHER
Bririsa Bens,

Lower | Middle | Upper ja...
Bala. Bala. Balen Silurian.

Cheirurus bimucronatus Murch. ...... * * *
sh elawifrons (? Dalm.) ......... * %
Spherexochus mirus, Beyr. ..........+ % % * *
Calymene Blumenbachi, Brong. ...... es % x *
Itlenus Bowmani, Salt. ..........ee00s % %
Staurocephalus Murchisoni, Barr. ... : * *
Phillipsinella parabola, Barr. ......... 5 *
Remopleurides longicostatus, Portl... i x
Lichas laratus, M‘Coy — ......ceeseseee =e * *
bs hibernicus, PO Bits. cca wiped vile %*
Promita WM" Cot, Saltisecs.<.00ecnse one *
Orthis calligramma, Dalm. ......... * * * *
ba) WACTORTIEs SOWE. stuevssomeivare suc’ % % * *
Jl SALLCRNGEA; OWS Ah. eee ead %¢ * *
ae WUMOrata, Behlobhis, cersesiwen coke * * *
hate OUOU OE Ma ie ik cowemaee: ere % x
, elegantula, Dalm. ..............: * * *"y
ny.) 1 PLQUCHMMT, SOW: Vsccseccacceecs: sa * ?
5, testudinaria, Dalm. .....5...640 % * * ak
vespertilio, Sone, camer! lowe ft * * *
Strophomena antiquata, Sow. ......... * “
i corrugatella, Dav. ...... se ~ * *
Triplecia insularis, Hichw. ............ Me * *
Hyattella Portlockiana, Dav. ......... %
Streptis monilifera, M‘Ooy i... o+...-- .s pa aa *%
Rafinesquina expansa, Sow. cusvo+re- % * ig “
fi DAG OIded |S. Bara tenes r *
Leptena rhomboidalis, Wilck. ......... * * * *
Christiania tenuicincta, M‘Coy ...... * *
Plectambonites transversalis, Dalm. . * ne *
quingquecostata, M‘ Coy : * % *
Camerella ? Thomsont, Day. 2-0-0: *
Atrypa marginalis, Dalm. ............ ae *
? Ptilodictya costellata, M‘Coy ...... *
Holopea concinna, M‘Coy ............ *
sf SUMGLENG SOW, sdscueCaeeo ones %
?Pterinea subfalcata, Conr. (var.
CNG ASCETTELER 2) ce eo Pr eae ie *
Spheronites pyriformis, Forbes ...... mee *
| Prasopora Graye, Nich. & Eth. ...... *
| Halysites catenularia, L. .......0..2-4+ * * Ca *
Stenopora fibrosa, Goldf. ..........0.+6- * *
? Nebulipora lens, M‘Coy _ ............ “ *

Streptelasma europeum, F. Rom. ... *

eS

Vol, 53.] FAUNA OF THE KEISLEY LIMESTONE. 95

It is clear that the bed contains a fauna with Middle and Upper
Bala rather than Lower Bala affinities; and the occurrence of the
species Staurocephalus Murchisoni, Phallipsinella parabola, Remo-
pleurides longicostatus, and Spheronites pyriformis, which do not
range down below the Upper Bala, points to the inclusion of the
bed in the Upper Bala. The presence of some Silurian species might
incline us to assign to the Keisley Limestone a somewhat high
position in the Upper Bala; but on comparing the lists of the fossils
from the Stawrocephalus-zone and the Ashgill Shales in England and
Wales with the list from the Keisley bed, it is at once apparent that
the relationship is much closer with the former than with the latter.

Thus, in the Stawrocephalus-zone, we find the following Keisley
species present :—

Remopleurides longicostatus. Christiania tenuicincta.
Illenus Bowman. Orthis calligramma.
Lichas laxatus. » elegantula.
Phillipsinella parabola, » testudinaria.
Cheirurus bimucronatus. Leptena rhomboidalis.

5» juvenis (=clavifrons,? Dalm.) | Plectambonites quinquecostata.
Staurocephalus Murchisoni. Halysites catenularia.
Spherexochus mirus, Stenopora fibrosa.

In the Ashgill Shales and Redhill Beds, on the other hand, only
the following Keisley species are present :—

Calymene Blumenbacht. Orthis elegantula.
Cheirurus clavifrons. », testudinaria.
Orthis Actonie. 5» vespertilro.
» alternata. Leptena rhomboidalis.
», viforata. Christiania tenuicincta.
» calligramma. Holopea concinna.

The argillaceous instead of calcareous nature of the sediment,
and the different conditions of deposition, undoubtedly have much
to do with the different facies of the Ashgill Shale fauna. There
are, however, certain marked deficiencies in the Keisley Limestone
fauna when we compare it with any part of the Upper Bala. Thus
the genus Trinucleus is completely wanting, though T'r. seticornis
is a characteristic trilobite of the whole Upper Bala throughout
England and Wales. The two typically Ashgill Shale brachiopods,
namely, Ortlas protensa and Strophomena siluriana, are also con-
spicuous by their absence. The genus Phacops is completely absent
from Keisley, so far as is known, though this genus is very rich
in species and individuals throughout the Middle and Upper Bala
elsewhere.

The affinities of the Keisley Limestone fauna with that of the
Slade Beds and Hirnant Limestone are too remote to necessitate
entering into the question here.

Full weight must be given to the large number of peculiar
species found in the Keisley Limestone. Thus, of its well-deter-
mined species, omitting all those about which there is any doubt,
11 are absolutely peculiar to it, and 14 others are nowhere else
found in the United Kingdom except in the Kildare Limestone.

96 MR. F. R. COWPER REED ON THE [Feb. 1897,

The possession of so many peculiar forms stamps the fauna with a
distinct individuality and strongly differentiates it from all other
British beds.

Summing up, therefore, the paleontological evidence with re-
ference to its stratigraphical position, we find: (1) that the fauna
has a thoroughly Ordovician facies; (2) that it possesses a large
number of peculiar species; (3) that while possessing a considerable
number of Middle Bala species, yet the presence of certain forms
known elsewhere only from or only commencing in the Upper
Bala Beds points to a closer relationship to the latter than to the
Middle Bala; (4) that the affinity of the fauna is much closer with
that of the Staurocephalus-zone than with that of the overlying
Ashgill Shales; (5) that the presence of so many peculiar forms, as:
well as the absence of certain typical species of the Stawrocephalus-
zone, precludes us from considering the Keisley Limestone and
Staurocephalus-zone to be on exactly the same horizon, while the
presence of a number of Middle Bala forms inclines us to put the
Keisley Limestone slightly below rather than above the Stauro-
cephalus-zone.

Thus it is at the bottom of the Upper Bala that on the strength
of the paleontological evidence I would put the Keisley Limestone..
Mr. Marr has arrived at nearly the same conclusion,’ for he says
that its fauna distinctly belongs to a lower horizon than the Ashgill
Shales, and he would place it immediately below the Staurocephalus-
Limestone as the uppermost bed of the Applethwaite Beds of the
Sleddale Group of the Coniston Limestone Series, that is, at the top
of the Middle Bala.

Sedgwick and Salter” assigned the fossils from this bed to the
Middle Bala group.

Trish AND CoNTINENTAL EQUIVALENTS.

Throughout the preceding description of the fauna of the Keisley
Limestone frequent reference has been made to the Chair of
Kildare Limestone, the Leptena-Limestone of Dalecarlia, and the
Borkholm and Lyckholm zones, which constitute Schmidt’s Stage F —
of the East Baltic provinces of Russia, and many of the Keisley
species have been mentioned as occurring in one or more of these beds..
A brief summary of the common species will bring out the close
relationship of these beds clearly. Unfortunately, only in the case
of the Kildare and Leptena Limestones has the fauna been to any
extent adequately worked out, and even in these two cases there is.
room for a further scrutiny. The lists of fossils from the Borkholm
and Lyckholm beds are very meagre. Schmidt,? however, states
that the Swedish Leptwna-Limestone of the Osmundsberg in Dalarne
which he visited seems perfectly identical with the white Bork-

1 Geol. Mag. 1892, pp. 97 & 445.

2 Cat. Cambr. & Sil. Foss. Woodw. Mus. (1873) p. 54, ete.

3 Quart. Journ. Geol. Soc. vol. xxxviii. (1882) p. 514; [quoted by Linnarsson],.
Zeitschr. d. Deutsch. geol. Gesellsch. vol. xxv. (1873) pp. 696-697.

Vol. 53.] FAUNA OF THE KEISLEY LIMESTONE. 97
holm Limestone, and he regards them as formed at the same time
in the same ocean. To support this view he quotes a list of
identical fossils from the same bed, amongst which we notice
several species which are not found on higher or lower horizons
in those districts. It is on this occurrence of peculiar species of
very limited vertical range that we must depend for the correlation
of beds in distant lands, as is notoriously exemplified by the grap-
tolites and Ammonoidea.

The homotaxial equivalence of the Keisley Limestone with that
of Kildare is practically proved by the occurrence in both of the
following species (List I.), which are unknown from any other beds
in the British Isles. The presence also of the many common
species (enumerated in List II.) in these two limestones strongly
supports this conclusion.

List I.

Cyphoniscus socialis. Homalonotus punctillosus.
Cyphaspis ( Tornguistia) Nicholsont. Ilienus fallax.
Cheirurus cancrurus. ? ,, Roameri.

% keisleyensis. 214... Ce@eUus:

0 (Pseudospherexochus) con- | Harpes Wegelini.

formis. Cythere Wrightiana.

eC» ( - ) subqguadratus. | Atrypa expansa.

Fenestella assimilis.
Loxonema striatissimum.
Cyclonema rupestre.
sulciferum.

Spherexochus latirugatus.

? Spherocoryphe granulata.
Lichas bulbiceps.

? ,, bifurcatus. ce

Tiresias insculptus.

List II.

Cheirurus bimucronatus.
Tee clavifrons re
Spherexochus mirus.
Staurocephalus Murchisont.
Lichas laxatus.
. hibernicus.
Illenus Bowmant.
Remopleurides longicostatus.
Primitia M‘Coyi.
Atrypa marginals.
Orthis Actonie.
? ,, alternata.
» Otforata.
calligramma.
» jlabellulum.
? ,, testudinaria.
vespertilio.
Rafinesquina deltoidea, var.

Rafinesquina eapansa.
Strophomena corrugatella.

5% antiquata.
Leptena rhomboidalis.
Plectambonites quinquecostata.

= transversalis.
Christiania tenuicincta.
Streptis monilifera.
Triplecia insularis.
Hyattelia Portlockiana.
? Ptilodictya recta.
? Huomphalus subsulcatus.
Holopea concinna.
Conularia, sp.
Spheronites pyriformis.
Favosites alveolaris.
Stenopora fibrosa.
Halysites catenularia.

Turning now to the Leptena-Limestone of Dalecarlia we see
that the following species, peculiar to that rock in Sweden, occur
at Keisley. Those marked with an asterisk are doubtful at Keisley.

Cheirurus glaber.
Lichas conformis (var. at Keisley).
* Harpes costatus.
- Wegelini.
Homalonotus punctillosus,
*Huomphalus nitidulus,

Q. J.G. 8. No, 209. H

EHuomphalus obtusangulus.
EHunema carinatum.

* Orthis conferta.
Dayia pentagonalis,
Atrypa expansa

935 MR. F. R. COWPER REED ON THE

[Feb. 1897,

In addition to the foregoing the following Keisley species occur

in the Leptena-Limestone :—

Cheirurus (Pseudospherexochus) con-

Orthis biloba.

formis. » calligramma.
Spherexochus mirus. Strophomena corrugatella.
* Spherocoryphe granulata. Leptena rhomboidalis.
Lichas affinis. ? Rafinesquina deltoidea, var. undata.
| dawatus. Plectambonites Schmidti.
Llienus fallax. ce quinguecostata.
3 | he@emert. Hyattella Portlockiana.
Orthis Actonie. * Heliolites dubia.
» otforata. Halysites catenularia.

The allied but not identical species need not again be mentioned.
The evidence already adduced is sufficient to show the homotaxial
equivalence of the beds.

With regard to the Russian eae Schmidt, as above mentioned,
has insisted that the Leptena-Limestone is on the same horizon as
his Borkholm zone. It is confirmatory of my conclusions as to the
homotaxial equivalence of these beds that several Kildare fossils
which do not occur elsewhere in the British Isles are identical with
species from these Russian beds; as, for example, Lichas levis
(Kichw.) and LZ. margaritifer (Nieszk.).

The difficulty as to the stratigraphical position of the Leptena-
Limestone, indeed, enters into the above correlation. The diver-
gence of opinion on this point is well known. Briefly, one party,
respresented by Tornquist, places the Leptena-Limestone above
the etiolites-Shales; the other party, to which Schmalensee,
F. Romer, and Marr belong, put it immediately above the Trinucleus-
Beds and below the Rastrites-Shales. JI am not in a position to
criticize these two views, nor is this the occasion to do so, but I
may point out that Schmidt has indisputably established the strati-
graphical position and relations of the Borkholm zone in a region
in which the succession of the beds is not confused or indistinct
from deformation or dislocation of the strata; that he has proved
it to be at the top of the Ordovician System, and its fauna to be
essentially identical with that of the Leptwna-Limestone.

Tornquist ! has given the reasons for his view of the case in a
number of valuable papers. Marr?’ at first went with him, but
in 1885° rejected that view, although he expressed the opinion that
the Leptena-Limestone contained ‘ a mixture of faunas of several
of the Haverfordwest beds, viz. the Lower Llandovery, the Tri-
nucleus seticornis-beds, and perhaps even of the Robeston Wathen
Limestone.’

' *Om Lagerfolj. 1. Dal. undersil. Bilduing.,’ K. Vetensk. Akad. Forhandl.
1867 ; ‘ Geol. Iakt. o. d. Kambr. o. Silur. Lagf. i. Siljans.’ Ofv. K. Vetensk. Akad.
Férhandl. 1871, no. 1; ‘Om Siljans. Pal. Format.’ ibid. 1874, no. 4, p. 3;
‘ Berattelse, ete. aid. 1879, no. 2; Geol. Foren. i Stockholm Férhandl. no. 90,
vol. vii. (1884) pt. 6, p. 3804; ébed. vol. viii. (1886); zbzd. vol. xiv. (1892),
nos. 141, 147, ete.

2 Quart. Journ. Geol. Soe. vol. xxxviii. (1882) p. 313.

3 Ibid. vol. xli. (1885) p. 489.

Vol?'53.| FAUNA OF THE KEISLEY LIMESTONE. 99

Schmalensee’* has expressed the view that the Leptena-Limestone
corresponds with the horny Klingkalk immediately above the Tri-
nucleus-Shales, and Marr” likewise says that the Keisley Limestone
may be represented by a white horny limestone seen in the stream
at the Upper Bridge, Skelgill Brook, containing large Orthocerata
and occurring immediately below the Staurocephalus-Limestone.
Nathorst * illustrates this view of the occurrence of the Leptwna-
Limestone by a diagram showing the local swelling-ont of a thin
band of limestone into a thick reef-like mass. Ferd. Romer,* on
paleontological grounds, adopts the view that the Leptena-Lime-
stone is at the upper limit of the Lower Silurian [ =Ordovician ];
and Holm’ and Andersson,’ more recently, do the same.

It may be noticed here that several of the species limited in
Sweden to the Leptena-Limestone, in England to the Keisley
Limestone, and in Ireland to the Chair of Kildare Limestone occur
in the East Baltic provinces, not only in the Borkholm Limestone,
which Schmidt” correlates exactly with the Leptena-Limestone,
but also in the underlying Lyckholm zone. Thus Pseudospherex-
ochus conformis, Cheirurus cf. glaber, Cybele brevicauda,® Harpes
Wegelini, Lichas dalecarlicus, Bronteus laticauda, and Heliolites
dubia are recorded among others by Schmidt’ from the Lyckholm
zone, but in Sweden for the first and only time from the Leptena-
Limestone. Schmidt’ indeed says that the Lyckholm and Bork-
holm zones are so closely allied in their faunas that they cannot be
separated at present as distinct stages. Yet, on the other hand,
though he considers his Stage F to represent ‘the British Caradoc
Sandstone and the Coniston and Craighead Limestones,’ it is
remarkable that so many of its typical species do not occur in
Britain till the Keisley Limestone, which we have been led to place
at the base of the Upper Bala—e. g. Pseudospherewochus conformis,
Cheirurus cf. glaber, Illenus Remeri, I. cecus, Harpes Wegclini,
Plectambonites Schmidti, Cyclonema rupestre, Pleurotomaria notabilis.
It is also noticeable that several Keisley Limestone species are
very closely allied to forms not occurring in lower beds in Britain,
but in lower beds in Scandinavia. Of these the following are
examples :—Cheirurus keisleyensis, which is allied to Ch. subulatus
of the Trinucleus-Schists, and Cyphaspis Nicholsoni, which so much
resembles T’rilobites trira diatus of the same beds.

' «Om Leptenak. Plats i Silur. Lag.’ Geol. Foren. i Stockh. Forhandl. no. 89,
vol. vii. (1884), pt. 5, p. 280; ibid. no. 146, vol. xiv. (1892), pt. 6, p. 497.

? Geol. Mag. 1892, p. 97.

3 *Nagr. o. o. Slipsandst. i. Dal.’ Geol. Foren. i Stockh, Forhandl. no. 93,
vol. vii. (1884) pt. 9, p. 559.

* ‘Lethexa Erratica,” Palaont. Abhandl. Berlin, vol. ii. (1885) pt. v. p. 72.

° Sveriges Geol. Undersékn. ser. c, no. 115, pp. 14, 15, Stockholm, 1890.

® Ofvers. K. Sy. Vet. Akad. Forhandl. 50 Arg. p. 571, Stockholm.

7 Quart. Journ. Geol. Soc. vol. xxxviii. (1882) p. 514.

* This species is stated by Schmidt to occur also in his Stage E.

° ‘Rey. ostbalt. silur. Trilob.,’ pt. i. Mém. Acad. Imp. des Sci. St. Pétersbourg,
ser. 7, vol. xxx. (1881) no. 1.

© Quart. Journ. Geol. Soc. vol. xxxviii. (1882) p. 514.

H 2

100 MR. F. R, COWPER REED ON THE [Feb. 1897,

Spherocoryphe granulata, Illenus Remeri, and Plectambonites
Schmidti occur in the Trinucleus-Schists of Sweden as well as in the
Leptena-Limestone, but are kuown only from the Keisley Lime-
stone in Britain. Jllenus fallax, found only at Keisley and Kildare
in the United Kingdom, occurs as low down as the Chasmops-
Limestone in Sweden.

These facts appear to indicate that the species developed at an
earlier period iu Kastern Europe, and thence migrated in a westerly
direction. Marr’ has pointed to similar evidence in the case of
the Cystidean and Orthoceras-Limestones of Sweden and Russia.

MopE oF OccURRENCE AND CHARACTERS OF THE
KEIsLEY LIMESTONE.

The Keisley Limestone occurs as an isolated mass of limestone
on the western side of the southern end of the Cross Fell inlier.
The earliest mention of itis in a paper by Buckland ? in 1807.
Recently its relations have been described in brief by Marr
& Nicholson.2 The narrow elongated area which it occupies is
bounded on all sides by faults, and in no neighbouring locality is a
limestone with similar characters, thickness, and fossils known to
exist. Consequently, its exact stratigraphical relations and horizon
have been a matter of much dispute. The lithological characters
of the rock are by no means simple or uniform. The mass in fact
appears to consist of several more or less well-marked types, or
perhaps beds, of limestone with thin subsidiary shaly layers.

Thus, lithologically, we may distinguish the following more or
less distinct varieties of the limestone: (1) a pale pink, fine-grained,
compact, homogeneous limestone with comparatively few organic
remains and no crinoid-stems ; (2) a dark grey, bituminous, compact
or crystalline limestone, likewise poor in fossils and devoid of
crinoids; (3) a very coarsely crystalline, white or reddish-stained
limestone full of the characteristic fossils and many crinoid-stems.
The crystallization of the matrix in this case has extended to these
included organic fragments, as described by Prof. Nicholson *;
(4) a dark greyish compact limestone, not coarsely crystalline,
crowded with Orthoceras, but containing few other genera of fossils ;
(5) a pale greyish crystalline limestone with many fossils. Other
transitional varieties occur. Some layers of the limestone are full
of Illeni, and a dozen or more head-shields and pygidia may be
seen on a slab a foot or so square.

These varieties of texture and organic contents do not occur with

1 Quart. Journ. Geol. Soc. vol. xxxvi. (1880) p. 279; vol. xxxvili. (1882)
p. 313.

* Trans. Geol. Soc. ser. 1, vol. iv. pt. i. (1816) p. 105, pl. v., section, no. 3.
In this paper the limestone is apparently considered to be of Carboniferous
age.

3 Quart. Journ Geol. Soc. vol. xlvii. (1891) p. 507.

4 Nicholson & Lydekker, ‘ Manual of Palxontology,’ 3rd ed. (1889) vol. i.
p- 20, figs. 5a, 5d.

Nol. '53.|| FAUNA OF THE KEISLEY LIMESTONE. 101

much regularity or allow themselves to be traced far laterally, but
the greatest development of the dark bituminous, poorly fossiliferous
variety is found in the large quarry on the hillside, which is still
worked. This quarry lies at the foot of the hill, and shows a
southerly to south-easterly dip of these beds. On the higher slopes
the grey, pink, or coarsely crystalline varieties are met with, but
whether they lie above or below the bituminous variety is doubtful.

The red-staining of some parts of the limestone is undoubtedly
due to a comparatively recent oxidation of the contained iron, or
possibly to the infiltration of chalybeate waters.

The patchy manner in which some of the varieties of limestone
occur, even in the same hand-specimen, seems to point to original
slight differences in the deposit or to segregation at local centres
while the calcareous mud was soft. This ‘ patchiness’ is espe-
cially noticeable in the case of the fine-grained pink variety of the
limestone.

Some of the minute structural features are due to the dynamic
agencies which have affected the rock.

EVIDENCE oF DISTURBANCE.

Direct evidence of considerable mechanical disturbance of the
limestone is afforded by the twisted wisps of shales included in the
mass, as Marr & Nicholson have remarked (Joc. cit.). In the old
disused quarry, south of the one now worked, there may be seen
a section of a partially overturned fold, and of what appears to be
a thrust-plane, with considerable shattering and crushing of the
rock along the gliding-surface.

Marr & Nicholson believe that the limestone has been thickened
by the thrusting-up together of the calcareous portions and
squeezing-out of the shaly layers by the action of a force acting
from the south-west, and they mention that inversion of some of
the beds appears indicated by the occurrence of Jllent with their
convex surfaces downward. We must in fact regard the so-called
Keisley Limestone as a series of thin limestone-bands separated by
thinner shaly layers, which have been folded, crushed together, and
forced over each other so as to present a spurious thickness.

STRATIGRAPHICAL CoNSIDERATIONS.

Since we are led to regard the thickness of the Keisley Limestone
as largely due to mechanical deformation and not entirely to
original deposition, and the obscurity of its relations as due to its
isolation by faults, we might not unnaturally think that it was a
block of the neighbouring strata squeezed up and displaced. This
view, however, is seen to be utterly antenable when we ascertain
the unique facies of the fauna and its dissimilarity to that of any
other British beds (see infra). There is, however, an idea, which
at first sight appears probable, that the Keisley Limestone is the
sole remnant of what was once a widespread formation, which

102 MR. F. R. COWPER REED ON THE [Feb. 1397;

has suffered enormous denudation, leading to its complete removal
except in this one spot. Since everyone must concede, even from
the above evidence of the fossils, that the fauna has an Ordovician
facies, we look down the list of Ordovician rocks of the district to
see at what horizon it can be inserted. But there is no gap in
the series or trace of such a widespread denudation, at any rate
until we come to the top of the system, and at this point a difficulty
arises, for the authorities on this district are divided in their
opinions.

Marr & Nicholson’ do not mention any break between the Ordo-
vician and Silurian, but have traced the whole series in unbroken
succession from the rhyolite and ashes below the Oorona-beds up
into the Brathay Flags, which are of Wenlock Shale age.

The first-named author’ moreover states that he has not detected
any traces of the supposed denudation at the close of Ordovician
times in this area, and certainly if it really exists, the evidence of it
has not yet been published. In the Lake District, however, there
is a physical break between the Ashgill Shales and the overlying
series, which is marked in various localities by the well-known
conglomerate with Meristella (?) crassa. The great irregularity in
the thickness of the Ashgill Shales in that district is to be attributed
either to an overlap of the overlying strata or to an unconformity,
and several facts seem more in favour of the latter.’

Mr. Goodchild * is the main upholder of the denudation-theory in
the Cross Fell area, and he disputes the continuity of deposition
from Ordovician into Silurian times. Roughly dividing the Bala
rocks of the Cross Fell inlier into a lower ‘calcareous shale’
series and an upper ‘mainly calcareous’ series graduating into
each other, he says :—‘ The limestone of Keisley belongs, I believe,
to a higher part of this calcareous series than has been left by pre-
Silurian denudation elsewhere in the area under notice.’

If, however, we can show that the paleontological affinities of
the bed are not with the Ashgill Shales, but with beds below them,
we shall be forced on these grounds alone to reject the theory that
the limestone is the remnant of a bed at the very top of the Ordo-
vician System, unless, indeed, we betake ourselves to Barrande’s —
theory of colonies. Mr. Goodchild (loc. cit.) admits that the patch
of limestone is faulted-in all round, so that its relations to other
beds cannot be directly observed, but only inferred.

In a case, therefore, such as this, the determination of the exact
horizon must be made entirely from the evidence of the fossils and
the affinities of the fauna.

2 Quart. Journ. Geol. Soc. vol. xlvii. (1891) p. 500, and Geol. Mag. 1892,
p. 97.

2 Geol. Mag. 1892, p. 445.

3 Marr, Quart. Journ. Geol. Soc. vol. xxxiv. (1878) p. 871; T. M°K. Hughes,
Geol. Mag. 1867, p. 354; Aveline, Geol. Mag. 1872, p. 441, and ibid. 1876,
p- 282.

* Geol. Mag. 1892, p. 295.

Vol. 53.] FAUNA OF THE KEISLEY LIMESTONE. 103

ConDITIONS oF DEposiTION AND ORIGIN OF THE FAUNA
OF THE Kurs~tEY LIMESTONE.

The isolation of the patch of limestone at Keisley has been fully
emphasized, but, as already mentioned, Marr’ is inclined to think
that it is merely a very local development, under peculiar and very
restricted conditions, of a thin limestone underlying the Stauro-
cephalus-Limestone. A white horny limestone in Skelgill, and a
similar limestone in Swindale Beck may be, in his opinion, the
attenuated and lithologically-different representatives of the Keisley
mass. He adduces cases in other districts with beds of various ages
in which ‘ reefs’ or lenticular masses of crystalline limestone occur
on the same horizon as these horny limestones and in close con-
nexion with them. Such is the case with some Devonian lime-
stones near Torquay, with the Konieprus Limestone (Ff2) in
Bohemia, with the Leptena-Limestone and Klingkalk of Dalecarlia
(according to Nathorst”*), with the ‘knoll-reefs’ described by
Tiddeman,’ of Carboniferous age, south of the Craven fault in West
Yorkshire, and with some Devonian limestones of the Ardennes.
In all these instances the district and rocks in which they occur
have suffered great disturbance.

With regard to the Keisley Limestone, I am inclined to think
that we may best explain the fact that it is not palzontologically
represented elsewhere in the British Isles, except at Kildare, by
supposing that a wave of migration started from the Baltic towards
the close of Middle Bala times; that it travelled in a westerly
direction over Scandinavia, the North of England, and into Ireland,
but only in isolated spots—such as are now found in Dalecarlia,
Keisley, and Kildare—did the fauna which it bore (namely, the
fauna of Stage F of Western Russia) find the conditions suitable for
its settlement. In the intervening areas it was unable to exist, at
any rate in its entirety. Many of the species of the fauna of the
seas which it invaded continued to flourish alongside of it, and con-
tributed their remains to the formation of the limestone-patches.
On the surrounding portions of the sea-floor, thin horny lime-
stone accumulated in some parts, and in others shales, etc., but
without the peculiar fauna. After an existence of brief duration in
these isolated outposts, far removed from its original home, most
of the fauna died out, mainly owing to the cessation of favourable
conditions, but partly owing to the immigration of the new fauna
of the Stawrocephalus-zone. It left but few descendants behind it.

The facts in favour of the view that the existence of this fauna
was largely conditional on the physical and biological environment
are: (1) the presence of numerous specifically-identical forms,
although the localities are so widely separated one from another ;
(2) the absolute limitation of many of these forms to these patches
of limestone ; (3) the occurrence of blind species of Illenus with

* Geol. Mag. 1892, p. 97.
* Geol. Foren. i Stockholm Forhandl. no. 93, vol. vii. (1884) p. 559.
° Rep. Internat. Geol. Congr. 1888, pp. 319-822. .

104 MR. F. R. COWPER REED ON THE [Feb. 1897,

common structural peculiarities; (4) the similar lithological
character of the patches.

The evidence in favour of the brief duration of the fauna consists
in (1) the comparatively slight change in the peculiar facies of
the fauna, despite the considerable distance apart of the several
localities ; (2) the small development of local species or varieties ;
(3) the little impression that it has left on subsequent faunas.

So far, therefore, as our present knowledge goes, we may look
upon this ‘Stage F’ fauna as presenting an example of discon-
tinuous distribution. ‘The period during which the area of distri-
bution was continuous lasted only during the time necessary for
the migration, and it was therefore so transient as to leave scarcely
a trace behind in the intervening tracts between the few spots
where the fauna was able to take root. These spots now alone
indicate the size of the area over which the wave of migration
spread.

The fact that the limestone in each of these ‘outposts’ or
‘stations’ has suffered so much mechanical disturbance may,
perhaps, be in the main attributable to its reef-like nature and
mode of occurrence, as a local thickening of an elsewhere thin band
of rock. But I do not wish to generalize, or to imply that this
suggested explanation applies to those examples of ‘reefs’ among
Devonian and Carboniferous rocks which Mr. Marr has quoted
(loc. cit.). Each case must be decided independently and on its
own merits.

SUMMARY AND CoNCLUSION.

As the result of the above detailed inquiry into the characters of
the fauna of the Keisley Limestone and the relations of the rock,
it appears to me that the following facts are established :—

(1) The fauna has a thoroughly Ordovician facies.

(2) It is closely comparable with that from the Chair of
Kildare Limestone and that of the Leptewna-Limestone of
Dalecarlia, and less closely with that of Stage F of the
East Baltic provinces.

(3) Its paleontological features point to its stratigraphical
position being at the base of the Upper Bala.

(4) It must be regarded as the locally-thickened development of
a bed which is elsewhere in Great Britain very thin or
entirely absent, or represented by beds of entirely different
lithological characters containing a different fauna.

(5) The fauna has certain unique characters which mark it off
from all other known assemblages of fossils in Great Britain.

Note.—Recently I have been informed by Mr. R. Clark, of the
Geological Survey of Ireland, that the limestones of Toorma-
keady, Co. Mayo, Courtown, Co. Wexford, and Caherconree, Co.
Kerry, are lithologically and paleontologically (so far as the
fossils are known) identical with the Kildare Limestone. At present,

Vol. 53.] FAUNA OF THE KEISLEY LIMESTONE. 105

I have been unable, from lack of time, to confirm personally the
accuracy of this statement, which I find also appears in the
Geological Survey Memoirs dealing with those districts, but I intend
to take the earliest opportunity of visiting these localities. The
scanty lists of fossils from them which have appeared in the
Explanations of Sheets 160, 161, ete. (1863), p. 12 (Caherconree) ;
sheets 148, 149 (1887), pp. 21-24 (Courtown); sheets 73, 74,
etc. (1876), pp. 28, 31, and 33; and sheets 93, 94, etc. (1878),
p-114 (Toormakeady), certainly contain several of the Kildare species,
and the specimens of the rocks which I have seen bear a remark-
able resemblance to the Keisley and Kildare Limestones. If it be
subsequently established by more minute investigation that these
patches of limestone at Toormakeady, Courtown, and Caherconree
are of the same age as that at Keisley, none of the conclusions
arrived at in this paper will have to be rejected, but these three
localities will have to be quoted as additional ‘ outposts’ of this
peculiar fauna.

EXPLANATION OF PLATE VI.

Fig. 1. Orthis (Hebertella ?) keisleyensis, sp.n. Pedicle-valve. x3.
la. Outline of side view of pedicle-valve. 3.
16. Natural size.
2. Atrypina similis, sp.n. Pedicle-valve. X93.
2a. Brachial-valve (young individual). x3.
26. Natural size.
3. Atrypina similis, sp.n. Brachial valve. X93.
3a. Natural size.
4. Syntrophia affinis, sp.n. Pedicle-valve. X3.
4a. Natural size.
5. Dayia pentagonalis, sp.n. Brachial valve. 3.
5a. Pedicle-valve. x3.
56. Anterior margin of valves. X93.
5e¢. Natural size.
6. Loxonema striatissimum (Salter MS.). Natural size.
7. Platyceras verisimile, sp.n. 2.
7a. Side view. X2.
76. Natural size.
8. Murchisonia, sp. X98.
8a. Natural size.
9. Anodontopsis, sp. X38.
9a. Natural size.

DIscussion.

Mr. Marr could not, at the late period of the evening at which
the paper concluded, say much upon the points where he agreed
with the Author, so would speak at once regarding matters on which
he disagreed. He doubted whether the limestones of Keisley were all
upon one horizon, though there certainly was a very definite fauna
intermediate between that of the Applethwaite Limestone and that
of the Staurocephalus-Limestone ; whether that fauna was referable
to Middle or Upper Bala depended upon the line taken between
these two groups—which had been originally separated one from
another by Sedgwick on stratigraphical grounds, though he (the

106 THE FAUNA OF THE KEISLEY LIMESTONE. [Feb. 1897,

speaker) had attempted to define the base of the Upper Bala in
Britain upon paleontological grounds. The Author was mistaken
in saying that the speaker considered the Keisley Limestone a local
development ; what he did think was that its peculiar features at
Keisley were due to subsequent earth-movement. Finally, he
disputed the statement that Trinucleus seticornis was a characteristic
Upper Bala fossil. The type (in Sweden) came from Middle Bala
beds ; it was very common in Middle Bala beds in Britain, and, so
far as the speaker’s experience went, rare in Upper Bala beds.

Dr. G. J. Hnypz enquired of the Author whether he had compared
the fauna of the Keisley Limestone with that of the Hudson River
formation of Kastern North America, and more particularly with
that shown onthe Island of Anticosti. Judging from the specimens
exhibited, it seemed to the speaker that there were several species
common to these widely-separated areas.

The AvTHoR, in replying to Mr. Marr, who objected to the use
of percentages in determining the relations of faunas, held that
percentages were merely a concise way of stating ascertained facts,
and were only misleading when the special conditions and modifying
circumstances of each case were left out of account. Mr. Marr also
denied that Zrinucleus seticornis was specially characteristic of -
Upper Bala beds, though some years ago he had called the Upper
Bala beds of the Haverfordwest area after that fossil. From the
examination of a very large number of so-called examples of this
species from the Middle Bala, the Author could positively state
that the great majority of them were quite distinct from the
common form which bears this name in Upper Bala beds. He had
had no opportunity of comparing the Keisley Limestone fauna with
that of the Hudson River Group.

Cusre Journ Geolkooc. Vol Al PLVL.

FH.Michael del.et tith .

BRACHIOPODA AND MOLLUSCA
PROM toe KEISLey LIMESTONE.

Mintern Bros.imp.

Vol. 53.] ANOTHER POSSIBLE CAUSE OF THE GLACIAL EPOCH. 107

6. Another Posstste Cause of the Guactan Epocu. By Prof.
Bowsre ‘Hui, MA. ED RR BG.o: |” (Read
December 2nd, 1896.)

[ Abstract. |

In the introductory portion of the paper the Author gives an
account of the submarine topography of the area east of North
America, and summarizes Dr. J. W. Spencer's work upon a
submerged Antillean continent; he then deals with the effects
which would be produced upon the Gulf Stream by the uprising of
this continent in the Glacial Period, and maintains that, as the
current could not pass into the Gulf of Mexico (being debarred
by a coast of high continental land), it would flow directly north-
wards into the North Atlantic, and thereby be deprived of about
10° (Fahr.) of heat: the effects of which may be practically
illustrated by supposing the isothermal line of 32° to take the
place of that of 42° in the northern hemisphere. He argues that
the increased snowfall which would thus be caused over certain
areas would tend to intensify the cold through all the adjoining
tracts.

To the effects produced in this way must be added those due to
the elevation of the land of Eastern North America and to an
elevation of North-western Europe, which is supposed to have
occurred at the end of Pliocene times. These elevations would
intensify the glaciation caused by the difference of direction taken
by the Gulf Stream.

Discussion.

The Rev. Epwiy Hitt, while welcoming the paper, refrained
from discussing Prof. Spencer’s views or the influence on climate of
the Gulf Stream. There remained the real point of the paper—a
suggestion that Prof. Spencer’s views involved a deviation of the
Stream—a new suggestion. He wished to know the grounds for
the estimated reduction of temperature, and would be glad to have
a comparison between the Gulf Stream in such conditions and the
present North Pacific current ; also a discussion of the effects on
the winds which cause currents. It must be remembered, moreover,
that a deviation in the Stream might throw more of it onto our
coasts. A good review of the question would be valuable.

Dr. Buanrorp agreed with the previous speaker in feeling doubtful
whether a change in the configuration of the American coast would
prevent a warm current from still impinging upon the shores of
North-western Europe. He also called attention to the circumstance
that evidence of Pleistocene glaciation was not confined to the
neighbourhood of the Atlantic, but had been clearly shown to exist
in other parts of the world—for instance, the Himalayas and New
Zealand. The speaker expressed his opinion that the main cause
of the Glacial Epoch was still unknown.

The AvurHor, in reply to Mr. Hill, stated that he could not dis-

108 ANOTHER POSSIBLE CAUSE OF THE GLACIAL EpocH. [ Feb. 1897,

sociate his argument from the conclusions of Prof. Spencer; and as
regards these conclusions, they had not been challenged by any
American geologists with whom he had been able to confer, nor by
Mr. Jukes-Browne, who had reviewed Prof. Spencer’s memoirs in the
pages of the ‘ Geological Magazine.’

Replying to Dr. Blanford with reference to his remarks on the
Pleistocene extension of the Himalayan glaciers, of which he (the
Author) had been fully aware, it seemed to him that any great
refrigeration of the climate over Western and Northern Europe
would extend its influence even into the heart of Asia. At the same
time the objection was not very easy to meet, except by supposing
an elevation of this region to a greater extent than at present.’

1 [The Author has since dealt with this point in the ‘ Geological Magazine ’
for January 1897, p. 48.]

Vol. 53.] PROF. E, KAYSER ON VOLCANIC BOMBS IN NASSAU. 109

7. Nore on Vorcanic Bomss im the Scnatsterns of Nassau. By
Prof. E. Kayser, Ph.D., For.Corr.G.8. (Communicated by the
Secretary. Read December 16th, 1896.)

Tue origin of the schalsteins of Nassau, the Harz, and other districts
has remained hitherto an unsolved enigma for geologists. This,
however, is not surprising, considering the very variable nature of the
rocks. Generally of greyish-green colour, with highly-developed slaty
cleavage, and with a large admixture of calcareous and chloritic
matter, the schalsteins are sometimes earthy, sometimes coarse-
grained to conglomeratic and brecciated—and in this latter case
they contain frequently fragments of foreign rocks of extremely
diverse derivation, such as diabase, porphyry, limestone, slate, etc.
The schalsteins are, moreover, sometimes fossiliferous and distinctly
bedded, and sometimes unfossiliferous, with as little evidence of
stratification as an eruptive rock.

Some geologists consider the schalsteins as originating from a
mixture of disintegrated diabases and ordinary argillaceous mud ;
others see in them a product of metamorphic processes ; while most
observers look upon them as volcanic tuffs, but greatly changed
in consequence of their great age. That this last opinion is the
only correct one seems clearly proved by the bombs which I have
discovered.

These bombs are found in great numbers in two localities in the
neighbourhood of Oberscheld, near Dillenburg: firstly in the vicinity
of the village of Bicken (well known to the paleontologist on
account of the occurrence there of Hercynian and Upper Devonian
fossils), in a fine, earthy schalstein, very well stratified; and
secondly, close to Oberscheld, in a slaty rock, less clearly stratified.

In the first locality the rock forms a small hill, projecting from
the surrounding Culm Measures and constituting geologically an
anticlinal fold; in the second locality it is only separated from the
superjacent Culm Measures by a moderately thick layer of diabase.
The above-mentioned schalsteins must, therefore, belong to the
uppermost horizon of the Upper Devonian. ;

The bombs are generally rounded, sometimes, however, angular ;
varying in size from that of a walnut to that of a man’s fist, but
sometimes as big as a man’s head. They consist of a kernel of
coarse-grained rock resembling gabbro, with a comparatively thin
rind of ‘mandelstein.’ The kernel is composed, according to the
researches of my colleague, Prof. M. Bauer, of a crystalline aggregate
of calcite, mica, chlorite, and other minerals, and represents frag-
ments of limestone altered by contact-metamorphism. The rind is
1 to 2 centim, thick, generally finely porous, but contains occasionally
very large bubble-cavities, filled with calcite or zeolites

The Oberscheld bombs are therefore very similar to the well-
known bombs of olivine, mica, hornblende, etc., encrusted with a
rind of lava, found in the tuffs of the Eifel, Auvergne, and other
volcanic districts.

[ tBaUTT 2 qnoqe : eTeog |

(ydvaboqoyd 0 wow) “pyayasuaqg unou baogspadunay 40
‘squiog 9vuna}0a poppaqua oy, buamoys “(firj-asvgnrp) majspoyas ur aonf-hasonb fo w0rp.og

Vol. 53.] PROF. E. KAYSER ON VOLCANIC BOMBS IN NASSAU. EE

Together with the contorted diabasic lavas, also found in recent
years in the Dillenburg area, and doubtless representing the super-
ficial part of old lava-streams, these bombs undoubtedly prove that
volcanic action in that far-off Paleozoic time was similar in all
essential points to volcanic action in our own days. The bombs
further demonstrate the explosive character of this volcanic action.
Near Oberscheld and Bicken volcanoes must have arisen in Devonian
times, from whose craters vast quantities of earthy or ashy materials,
and innumerable fragments of the rocks, existing deep down below
the surface and forced up by the escaping steam, etc., have been
ejected. Thus did many fragments come into contact with the
molten lava ascending through the same funnel, and were coated
with a crust of lava, the above-mentioned mandelstein-rind.

Although, in the course of countless ages, every trace of the out-
ward form of these old volcanoes has been destroyed, yet the bombs
here preserved, which were ejected from them, demonstrate clearly
the existence of the craters and show that their activity was in
every respect similar to that of recent volcanoes.

te _ DR. J. W. GREGORY ON THE [Feb. 1397,

8. On the Arrinitiss of the KcHINoTtHURIDm; and on PEDINOTHURIA
and HELIKODIADEMA, two NEw GuneRA of Ecurnorpna. By
J. W. Greeory, D.Sc., F.G.S., F.Z.8., Assistant in the Geological
Department, British Museum. (Read December 2nd, 1896.)

[Pars VIL]

Tue genus Echinothuria was founded by 8. P. Woodward ' in 1863
to include two Chalk fossils in the British Museum (Nat. Hist.). The
specimen first discovered was found at Rochester, and it was regarded
as a fossil cirripede until Darwin refused to accept it as a member
of that class. Ed. Forbes then proposed to describe it as an holo-
thurian, but finally declined this responsibility. It was not till the
second specimen was found at Charlton by the Rev. J. N. Glass that
the two fossils were recognized as probably fragments of an abnormal
echinid. §. P. Woodward discussed the possibility of the fossils
being holothurians or allied to Paleozoic echinids, such as Proto-
echinus; but he rejected both ideas, and cautiously described the
specimens as belonging to a new genus of echinoderm, of which the
affinities ‘ are still matter for conjecture.’ He remarked that ‘the
disviples of von Baer may regard it it as a “‘ generalized form” of
echinoderm’; but he shows that he realized one strong objection
to this view, by pointing out the fact of the fossil ‘coming, how-
ever, rather late in the geological day.’

The importance of the genus Hchinothuria was not fully appre-
ciated until 1873. In that year Sir Wyville Thomson’ published
an account of some recent echinids with flexible tests: for one
series of these he proposed the name Calveria, but this has since
made way for that of Asthenosoma, which had been given by Grube ®
in 1868. Thomson recognized the affinity of the deep-sea species
with the Chalk fossil, and included both, with a third genus Phor-
mosoma, 1n a new family—Hchinothuride. |

The possible affinity of these flexible echinids with the Paleozoic
genera at once aroused the interest of paleontologists. Prof. J.
Young,’ in 1873, and Mr. R. Etheridge, Jun., in 1874, promptly
called attention to the resemblances between them. The latter
author welcomed the new genera as throwing light on the relation-
ship between Paleeozoic and recent Kchini, and as serving ‘to unite

1 «On EKchinothuria floris,a New and Anomalous EHchinoderm from the
Chalk of Kent,’ Geologist, vol. vi. (1863) pp. 327-330, & pl. xviii.

2 «The Depths of the Sea,’ 1873, pp. 155-159 ; ‘On the Echinoidea of the
Porcupine Deep-Sea Dredging Expedition,’ Phil. Trans. Roy. Soc. vol. elxiy.
(1874) pp. 730-737.

3 « Asthenosoma variwm, nu. sp.,’ Jahresber. Schles. Gesellsch. Breslau, vol. xlv.
(1868) pp. 42-44.

4“On a Carboniferous Genus of Echinoderms with Overlapping Plates,’
Geol. Mag. 1873, pp. 301-503.

Vol. 53. | AFFINITIES OF THE ECHINOTHURIDZ. 113

the echini of the present seas with certain of those genera which
existed during Paleozoic times.’ *

The view of the close affinity of the Echinothuride with the
Paleozoic ‘ Perischoechinide’ was not allowed to pass unchallenged.
It was denied by the late W. Keeping,” from a study of the fossil
forms, and by Prof. F. J. Bell* in his classification of the recent
families. Bell, however, still regarded the gap between the Kchino-
thuride and other ectobranchiate echinids as very marked. He
included the family in his Ectobranchiata, which he divided into
two series: one of these, the Neoproctous, included all regular
echinids except the Cidaride and Saleniide; it was subdivided
into two subseries, the ‘ polylepid,’ including only the Kchino-
thuride, and the ‘ decalepid,’ containing all the rest.

Prof. A. Agassiz, about the same time, also clearly recognized
the affinity of the Echinothuride with the typical families of living
ectobranchiate echinids. He even remarked? that ‘it is difficult
to separate this group of echinids as a distinct family from the
Diadematide.’ But he counteracted this advanced view and gave
great encouragement to the older hypothesis by the remark ‘that
the Palachinide are far more closely allied to the recent echinids
than is usually supposed, and that we have in the recent Kchino-
thuride structural features combining the characteristics of the
normal Desmosticha and of the Palechinide.’ ’

This view received its most definite exposition in an important
memoir by the cousins P. & F. Sarasin,® published in 1888.
These authors, impressed by many remarkable features in the
anatomy of a new species of Asthenosoma (A. wrens), claimed that
the Echinothuride are the most primitive of living Echinoidea, and
established the origin of this class from an holothuroid ancestor.
They laid especial stress on the great size of the ‘ Stewart’s organs,’
on the presence of a series of powerful radial muscles, and on the
absence of the supposed calycinal system of plates. Bell,” however,
showed in 1889 that both the ‘ Stewart’s organs’ and radial muscles
are absent or rudimentary in the genus Phormosoma, and that these
organs therefore do not possess the importance attached to them
by the Sarasins.

1 «On the Relationship existing between the Echinothuride, Wyv. Thoms.,
and the Perischoechinide, M‘Coy,’ Quart. Journ. Geol. Soc. vol. xxx. (1874)
pp. 807-315, & pl. xxiv.

2 «Notes on the Palxozoic Echini,’ 2bd. vol. xxxii. (1876) p. 40.

° «Observations on the Characters of the Echinoidea, pt. iv.: The Echino-
er their Affinities and Systematic Position,’ Proc. Zool. Soc. 1881,

. 417.
eee on the Hchinoidea,’ Challenger Exped., Zool. vol. iii. (1881)

a Tih.
ae Ibid. p. 81.

6 ‘Veber die Anatomie der Echinothuriden u. die Phylogenie der Echino-
dermen,’ Ergebn. naturw. Forsch. auf Ceylon, vol. i. (1888) pp. 83-151.

7 “Report of a Deep-Sea Trawling Cruise off the S.W. Coast of Ireland
under the direction of Rev. W. Spotswood Green. Echinodermata,’ by F. J.
Bell, Ann. Mag. Nat. Hist. ser. 6, vol. iv. (1889) pp. 436-438.

Q.J.G.S. No. 209. 1

114 DR. J. W. GREGORY ON THE [Feb. 1897, —

Duncan, who carefully considered the Sarasins’ arguments during
the preparation of his ‘ Revision of the Genera and Great Groups of
the Echinoidea,’ did not accept their conclusions. He pointed out
the differences between the Paleozoic echinids and the EKchino-
thuride, and concluded that ‘it appears more reasonable to place
the Echinothuride near the Diadematide, granting some atavism,
than to station them at the end of the Palechinoidea.’’ Like Bell,
however, he separated them from the rest of his order, the Diadema-
toida (which included all Neozoic regular echinids except the
Cidaridze), as a special suborder, the Streptosomata.

Hence there have been, and still are, two opposite theories as to
the affinities of the Echinothuride. According to one school, the
characters of this family are primitive and ancestral; according to
the other, they are degenerate and highly specialized. As it is
impossible to progress with the phylogenetic classification of the
echinids until it be known whether the Echinothuride are a root
or whether they are a branch near the summit, I may be excused
for again calling attention to this question.

As we have already seen, it has been remarked by A. Agassiz,
Bell, and Duncan—to whom Neumayr’* may be added—that, in
spite of the resemblances between the Echinothuride and the
flexible Paleozoic echinids, this family is most closely allied to the
Diadematide. It was natural first to compare Asthenosoma with
Astropyga. But, as Wyville Thomson remarked in 1874, although
‘some characters would seem to indicate a tendency to a passage
from the Diadematide to the Echinothuride, through such forms as
Astropyga, the resemblances are for the most part superficial, and
very important anatomical characters maintain, according to our
present knowledge, a broad line of distinction between the
families.’* Astropyga is now recognized as a thin-tested member
of the family Pedinidxz, with no special resemblances to any of the
Echinothuride.

In most previous attempts to determine the origin of this family,
the living echinothurids have been taken as the starting-point.
The ancestry of the family is inferred from the characters of the
latest and most specialized, instead of from those of the earliest and
most primitive members. The best clue as to the origin of the
Kchinothuride is obtained from Pelanechinus, a Corallian genus
founded by W. Keeping,* and ably described by T. T. Groom.’ His
account leaves no doubt that Pelanechinus is an echinothurid, of
which family it is the oldest known form.

1¢A Revision of the Genera and Great Groups of the Hchinoidea,’ Journ.
Linn. Soc., Zool. vol. xxiii. (1891) pp. 39-40.

2 ‘Die Stimme des Thioersighar’ sl i. (1889) p. 377.

3 Phil. Trans. Roy. Soe. vol. elxiv. (1874) p. 732.

4 «On Pelanechinus,a New Genus of Sea-Urchins from the Coral Rag,’ Quart.
Journ. Geol. Soc. vol. xxxiv. (1878) pp. 924-930.

5 «On some New Features in Pelanechinus corallinus,’ ibid. vol. xliii. (1887)

pp. 703-714 .& pl. xxviii.

Vol. 53.] AFFINITIES OF THE ECHINOTHURIDA. 115

The Characters of the Ambulacra in the Echinothuride.—Since
Dunean’s classical paper on the’ ‘Structure of the Ambulacra of
some Fossil Genera and Species of Regular Echinoidea,’! it has been
universally admitted that the characters of the ambulacral plates
offer the best guidance in the classification of that section of the
class. These plates in <Asthenosoma and Phormosoma are very
different from those of any other living echinid. It will be
advisable therefore, in the first place, to endeavour to trace their
gradual development. In the living echinothurids the ambulacral
plates are all free; two-thirds of the pore-pairs occur in small
plates (‘ klasma-plates ’) lying along the horizontal sutures between
the remaining plates (fig. 1). Both characters remind us of the
ambulacral plates of some
Paleozoic echinids, which are Fig. 1.—Ambulacral plates of

multiserial, simple, and free. Ph
But in the living echinothurids yn Wey Uranus. (After

every third plate is a large

primary; and in spite of the

apparent irregularity of the
plates, they may be recognized . SD)

as occurring in triplets. This

is quite different from anything met with among the Paleozoic
echinids, and they agree fundamentally with the typical Diadema-
toida. If the Echinothuride are to be regarded as descendants
from the Paleozoic echinids, then compound ambulacral plates have
been twice independently developed from the simple primary plates
of the latter and of the Cidaride. This is not impossible, for
heterogenetic homceomorphy unquestionably occurs sometimes. It
is highly probable that echinids with ‘ arbacioid ’ ambulacral plates
have developed from forms with simple ambulacral plates, through
stages represented by the genera Salenia and Acrosalenia ; while
those with ‘diademoid’ ambulacral plates have developed through
forms such as Hodiadema and Archwodiadema. It is conceivable
that there may have been a third line along which the Echino-
thuridz have developed; but there is no evidence of any such deve-
jopment, and we ought not to assume this origin in face of actual
evidence for one which is inherently far more probable.

It will be remembered that the typical ‘ diademoid ’ ambulacral
plates consist of three primary plates fused into one (fig. 9, p. 121).
The middle primary is usually the largest. The gradual growth of
this central plate may be traced until the adoral and aboral plates are
cut off from the vertical suture-line, and thus become demi-plates
(fig. 6d, p. 118). By a further progress in the same direction, the
demi-plates are reduced to the condition of ‘klasma-plates,’ * detached

1 Quart. Journ. Geol. Soc. vol. xli. (1885) pp. 419-452.

? A name suggested for the small, eye-shaped plates, which are cut off from
contact with either the vertical suture running down the centre of the ambu-
lacral area, or that between the ambulacrum and interambulacrum, They
represent a stage of reduction further than that of demi-plates. From
«\daopa, a fraction,

12

116 DR. J. W. GREGORY ON THE [Feb. 18974

from both of the vertical sutures, and lying only on the horizontal
sutures (see fig. 1), as in Phormosoma Uranus. Now in Pelanechinus
the ambital ambulacral plates (fig. 2) each consist of three primary
ambulacral plates and three demi-plates and three klasma-plates, or
nine constituents in all. This ar-

rangement is apparently so complex Fig. 2.—Ambztal ambulacral
that Mr. Groom suggests that it is plate of Pelanechinus..
to be regarded as a new type of (After Groom.)
ambulacral plate. But the plates ia
near the end of an ambulacrum
consist of triplets, each composed
of a central large primary with a
demi-plate (or klasma-plate) above
and below it (fig. 3). This is the
arrangement of a typical ‘ diade-
moid’ plate. If we follow along
an ambulacrum of a Pelanechinis,
we find a gradual passage from
the simple diademoid triplets to
the large compound plates of the Fig. 3.—Peristomal ambula-

ambitus. These plates may, there- cral plates of Pelanechinus,
fore, be regarded as formed by the showing division into trip-
fusion of three diademoid plates. lets of the diademord type.

In the living Echinothuride the
ambulacral triplets are usually de-
scribed as formed of a large aboral
primary and two small demi-plates
in the adoral suture of the primary
(fig. 1, p.115). This view obscures
the diademoid structure of the plates.
If we examine the ambital plates
the usual view appears the natural
one. But if we examine the ambu-
lacral plates near the apex, we find
that they are composed of a central primary between an adoral and
an aboral primary, as, for example, in:;:Phormosoma bursarium
(fig. 4), and near the peristome the same arrangement recurs (fig. 5) ;
that is to say, the plates are typically diademoid, and agree in

arrangement with the equivalent
plates of Pelanechinus. From Fig. 4.—Ambulacral plates of

these upper plates we may follow Phormosoma bursarium near
the series downward, seeing the the apex. (After,A. Agassiz.).
gradual increase of the central

plate, and the reduction of the FOE
demi-plates until they occur as (e) eo)
small klasma-plates in the hori- 7

zontal suture. The develop-
ment of the plates shows, therefore, that the ambulacral plates

1 Quart. Journ. Geol. Soe. vol. xliii. (1887) p. 707. The author, however,
there regards the triplets as of the echinoid, and not of the diademoid type.

i 7
Vol. 53.] AFFINITIES OF THE ECHINOTHURID®. /

ought to be described as composed of a central primary between
aboral and adoral demi-plates; and of the pair of pore-pairs below
each primary, one belongs to the same triplet as the plate above,
and the other to that of the plate below. The limits of the triplets
in Pelanechinus are shown in fig. 5.
Peélanechinus and the living echinothurids, therefore, begin with
plates of identically the same
arrangement. In Péelanechinus Fig. 5.—Ambulacral plates of

three of the triplets fuse into a Phormosoma luculentum near
compound plate; while in Asthe- the peristome. (After A.
nosoma and Phormosoma, on the Agassiz.)

other hand, the triplets are broken
up—owing to reduction in the
calcification of the test.

It appears, therefore, possible
to explain the peculiar arrange-
ment of the ambulacral plates of
living echinothurids as due: Ist,
to the fusion of three diademoid
triplets ; 2nd, to their dissociation
part passu with the reduction of
the calcareous matter in the test, as the plates become thinner and
the test flexible. If this view be correct, then the flexibility of
the Echinothuride is a secondary character, and was not due to
inheritance from a flexible, Paleozoic ancestor. 7

The structure of the ambulacral plates seems conclusively to
prove that the Echinothuride are members of the order Diademoida.
The question arises whether the members of this family have
descended from a diademoid ancestor, or whether the rest of that
order have descended from an echinothurid.

That the former alternative is the true one is rendered probable by
several reasons :—lIstly, the Echinothuride are younger than many
of the Diademoida, for this order begins in the Lower Lias, while
the family does not appear until the Corallian; 2ndly, the oldest
form of echinothurid is more nearly allied to the nearest diademid
than are the later, and apparently more primitive, members of
the family. To accept the other alternative would make diademids
found in the Lower Lias, and even some older forms occurring in the
Trias, descendants from genera not known to occur earlier than the
Corallian.

Let us therefore next enquire whether there be any member
of the Diademoida, of Corallian or pye-Corallian age, from which
Pelanechinus could have been derived.

Neumayr * has already suggested that the evolution of the family
was through ‘a series from Hemipedina by Pelanechinus to the
Echinothuride.’ It is true that the only species of Pelanechinus
‘was originally described as an Hemipedina*; and the two genera

1 ‘Ueber Palechinus, Typhlechinus, und die Echinothuriden,’ Neues Jahrb-
41890, vol. i. p. 85.

* ZH, corallina, Wright, ‘ Monogr. Brit. Foss. Ech. Ool., p. 163, pl. xii. fig. 1.

118 - DR. J. W. GREGORY ON THE [Feb. 1897+

agree in having perforate, non-crenulate tubercles, and low, broad
interambulacral plates, each with a row of tubercles. But the
genera differ widely by the structure of the ambulacral plates. In
Hemipedina the compound

ambulacral plates are always Fig. 6.—Ambulacral plates of
formed of three primaries, Pedina. (After Duncan.)

and the pore-pairs are a simple
vertical series. But in Pelan-
echinus the pore-pairs are
triserial, We have therefore
to look for its ancestor
among the triserial Pedinidz,
and not among the uniserial
Diadematide to which Hemi-
pedina belongs.

Before following this clue,
however, we must remember that Duncan adopted a course which,
if agreed upon, would prevent the derivation of the Echinothuride
from such specialized Diademoida as the Pedinidz. Duncan divided
the order Diademoida into two suborders—the Streptosomata,
including the Hchinothuride, and the Stereosomata, including the
rest of the order. He defined the Streptosomata as follows ! :—
‘Test more or less flexible, with external and internal branchie.
Ambulacral plates alone continued beyond the peristome to the
stoma.’ But all these characters also occur among the other
suborder, the Stereosomata. In the pedinid Astropyga and the
diademid Helikodiadema (see wmfra, p. 121) the test is more or less.
flexible. Both external and internal branchie are as well developed
in Diadema as they are in Phormosoma.’ In those of the Stereo-
somata which have plates on the peristomal membrane, these are
always ambulacral.

Hence Duncan’s diagnosis is useless, and there is no evidence to
show that the Echinothuride diverged from the main diademoid
stem at a very early period. We may search therefore among the
triserial members of that order for a suitable ancestor for the
echinothurids. Of all the Pedinide, Pedina is most like Pelan- ©
echinus. The interambulacral plates have the same tuberculation,
for in both genera they are multiserial, perforate, and non-
crenulate.

The ambulacral plates of Pedina show a series of stagés between
simple diademoid plates and those of Pelanechinus. The ambital
plates of Pedina usually consist of three primaries, of very unequal
size. Insome cases the middle primary increases so much in size that
it crowds out the other two constituents and reduces them to demi-
plates (fig. 6). These demi-plates may even lose any connexion
with the vertical suture between the ambulacral and interambulacral
areas; they are thus reduced to the position of klasma-plates on
the horizontal sutures between the primaries. Plates in this

1 Journ. Linn, Soc., Zool. vol. xxiii. (1890) p. 25.
2 F. J. Bell, Ann. Mag. Nat. Hist. ser. 6, vol. iv. (1889) p. 437.

Vol. 53.! AFFINITIES OF THE ECHINOTHURID2. 119

condition are not common in Pedina; but they do occur, and they
are identical in arrangement with the ambulacral plates near the
apex of Pelanechinus and Phormosoma.

Thus Pedina suggests the point at which the echinothurid branch
diverged from the main diademoid stem. The gap between Pelan-
echinus and the nearest member of the rest of the order Diademoida
is bridged by a new echinid from the German Jura, which I have
accordingly named Pedinothuria. Its test being small and rigid, it
appears to be nearer to the Pedinide than to the Echinothuride.

PEDINOTHURIA, gen. Nov.

Diagnosis—Pedinide with the test small, rigid, and turban-
shaped.

Apical system large, its diameter about half that of the test.
The arrangement of the plates is unknown.

Ambulacra.—Near the apex the plates are simple primaries.
At the ambitus the pore-pairs are biserial, owing to the reduction
of alternate primaries to demi-plates. Below the ambitus the pore-
pairs are triserial, owing to the presence of a second demi-plate on
the horizontal suture between two primaries.

Near the peristome the plates are not compound; they are all
demi-plates, and occur in three series. Those of the median series
are the largest, and they may bear a miliary granule. .

There are no primary tubercles on the ambulacra ; but two rows
of small, regular granules run down each ambulacrum. Near the
peristome they are small, and limited to the primary plate on
which they occur.

Interambulacra.—The plates are unituberculate. Upon each
there is a prominent, primary tubercle, which is perforate and
crenulate. About seven in each vertical series. The mamelons
are perforated. Near the peristome the ambulacra are broader than
the interambulacra.

Peristome small; branchial slits very deep.

Distribution —Jurassic, Germany.

PEDINOTHURIA CIDAROIDEs, sp.noy. (Pl. VII. figs. 1-3.)

Diagnosis.—Test circular, depressed. Oral surface very flat ;
aboral half slightly tumid.

Apical system slightly more than half the width of the test
in diameter.

Interambulacra.—Seven plates in each vertical series. Scrobi-
cular areas confluent. Miliary granules scarce.

Ambulacra.—Structure as in generic diagnosis. The change
from the uniserial to the biserial arrangement of the pore-pairs
occurs at the 12th or 13th plate from the apex.

Dimensions.—Diameter, 12 millim.; height, 5 millim.; diameter
of apical area, 7 millim.; diameter of peristome, 4 millim.; width
of ambulacrum at ambitus, 24 millim.; width of interambulacrum

120 _ DR, J. W. GREGORY ON THE [ Feb. 1897,

at ambitus, 5 millim.; width of interambulacral plates in each
series, 7 millim. .

Distribution.— Weisser Jura,Germany. Type, B. M., no, 34,724.

Affinities.—This specimen was sent to the Museum labelled Diplo-
cudaris. Its deep branchial slits and compound ambulacral plates
show that it cannot belong to the order Cidarida. There can be no
doubt that it is a member of the order Diademoida, for the genus is
regular and ectobranchiatc. It is distinguished from the suborder
Calycine (including the Saleniide and Acrosaleniide), in the absence
of knowledge of the structure of the apical system, by the com-
plexity of the ambulacral plates. From the suborders Arbacina and
Kchinina it differs in having the ambulacral plates diademoid,
instead of on the arbacioid or echinoid type. The genus falls easily
into the suborder Diademina, owing to the character of the ambu-
lacral plates. In this suborder there are six families; of which
the Orthopside have simple ambulacral plates; the Diadematide
and the Diplopedinide respectively have regularly uniserial and
biserial pore-pairs ; the Cyphosomatide have the pore-pairs in high
curved arcs. This leaves only the two families of the Pedinide and
Kchinothuride, with both of which the genus agrees in some
respects. Thus the ambulacral plates may consist of a central
primary and two demi-plates, one or both of which may be further
reduced to klasma-plates. The plates just below the ambitus of
Fedinothuria agree exactly with those of Asthenosoma, except that
they are thicker and solidiy united to their fellows. They are more
of the echinothurid type than of that of Pedina. Nevertheless,
owing to the rigidity of the test, and the unituberculate, cidaroid
character of the interambulacral plates, it appears advisable to
include the genus in the family Pedinide.

The exact horizon whence the fossil came is unfortunately
unknown. It is simply labelled ‘ Weisser Jura, Germany.’ The
test has apparently been washed in weak acid, and thus it may not be
sate to guess its horizon from its appearance. But, as far as I can
judge, it probably came from either Western Bavaria or Wirttem-
berg, and from the horizon y of the Weisser Jura. In that case it
would be older than the earliest echinothurid, which lived in the ©
succeeding stage of the Weisser Jura e.

As the main difference between Pedinothuria and Pelanechinus is
that the latter had a somewhat flexible test, it is advisable to
consider the value of this character. The evidence of Astropyga
and of the deep-sea spatangids, such as Calymne and Oystechinus,
shows that flexibility is not limited to a single family, and may be
independently acquired; it is probably due to changes of environ-
ment leading to diminished calcification of the test. We must
therefore be prepared to meet with imbricating-plates in any group
of echinids,

In various Mesozoic rocks there occur isolated plates, with
truncated margins, which, if imbrication and flexibility were
limited to the Echinothuride, would have to be referred to that

Vol. 53.] AFFINITIES OF THE ECHINOTHURIDE. 121

family. S. P. Woodward called attention to these plates in his
original description of Echinothuria. Spines had previously been
figured by Forbes, first as belonging to Micraster* and then to
Cidaris” S. P. Woodward* and Wright * showed a truer apprecia-
tion of their characters by assigning them to Diadema. At this
time, however, the echinid was known only from isolated plates.
In Wright’s ‘Monograph of the Cretaceous Hchinoidea’ a better

Fig. 7.—Ambulacral plates of Fig. 9.—Ambulacral plates of
Helikodiadema at summit Helikodiadema adjoining
of ambulacrum. peristome,

O @

Fig. 8.—Ambital ambulacral Fig. 10.—Genital plate of
plate of Helikodiadema, Helikodiadema.

specimen was figured, with the plates in their relative positions : °
it was named Pseudodiadema fragile. The structure of the ambu-
lacral plates was not shown; but the accompanying figure (7)
of a specimen in the British Museum (B. M. 46,781) shows that the
plates are diademoid.

The echinid is most nearly allied to Pseudodiadema, but the
differences between it and that genus seem well worthy of generic
distinction. I therefore describe it as follows :—

Hetixoprapema,® gen. nov. (Figs. 7-10.)

Diagnosis.—Diadematide with a large, flexible test, composed of
thin, loosely-fitting plates. Peristome and periproct large. Peri-
gnathic processes slender.

* E. Forbes, in Dixon’s ‘ Geol. Suss.,’ Expl. of pl., p. x, pl. xxv. fig. 28.
2 Id., Dec. Geol. Surv. no. iii. pl. x. fig. 15.

3S. P. Woodward, zbid. no. v. pl. ii. p. 11.

4 Wright, ‘Monogr. Cret. Ech.’ pl. xiv. fig. 2.

° Jbid. pl. lxxx.

® From éAckos, twisting.

122 AFFINITIES OF THE ECHINOTHURIDZ. [Feb. 1897,

Apical system apparently a single circle of ten plates. Genital
plates pentagonal and large.

Ambulacra.—The plates near the apex are primaries. At the
ambitus they are of three fused primaries. Near the peristome
they are crowded, and demi-plates are numerous.

Tubercles perforate and crenulate.

Spines annulated, fluted, hollow.

Distribution.—Chalk, England.

Type Species.—Helikodiadema fragile (Wilts.), of which the
synonymy is as follows :—

Cidaris, sp., Forbes, 1850, in Dixon, ‘ Geol. Suss.,’ Expl. of
piAp. x, plo xxy. fe 26.

Mvecraster, sp., Forbes, 1850, Dec. Geol. Surv. no. iii. pl. x.
fig. 15.

Diadema, sp., 8. P. Woodward, 1856, Dec. Geol. Surv. no. v.
pl. u. p. 11; Wright, 1868, ‘ Mon. Cret. Ech.’ pl. xiv. fig. 2 ;
S. P. Woodward, 1878, in Dixon, ‘Geol. Suss.’ 2nd edit.
p. O72, plu xxv, [28] fig. 28:

Pseudodiadema fragile, Wiltshire, 1882, in Wright, op. cit.
ple Ixxax,

SuMMARY oF CoNCLUSIONS.

1. That the family Echinothuride is a member of the order
Diademoida, and is derived from the Pedinide.

2. That the oldest member of the family is the genus Pelanechinus,
and that the extreme flexibility and loose articulation of the plates
of the living genera Asthenosoma and Phor mosoma are due to
diminished calcification of the plates.

3. That the apparently primitive features of the Echinothuride
are secondarily acquired and are not primeval. The recent genera
are therefore extremely specialized, instead of being primitive forms.

4, A new genus Pedinothuria is a connecting-link between the
Pedinide and the Echinothuride.

5. A new genus Helikodiadema, which has a flexible test, is a
modified form of Pseudodiadema ; it has probably arisen from the
adoption of deep-sea life having resulted in diminished calcifica-
tion of the test.

[For Explanation of Plate VIL, see p. 134.]

Vol. 53.] ECHINOCYSTIS AND PALHODISCUS. 123

9. On Ecurnocystis and Patzxopiscus—two Srmvur1AN Genera of
EcurnomEa. By J. W. Grecory, D.Sc., F.G.8., F.Z.8., Assist-
ant in the Geological Department, British Museum. (Read
December 2nd, 1896.)

[Puate VII.]

ConTENTS. Page
Amt YOGUehOW? scsrceness- con. ohitas ocee ou asceunee noes vacwaae aleve: 123
bie History efithe Genera’ Ril cgese.ts sores octiceusvaceuts-aueeae 124
Ti, TheiStructiwe of Menimocyseis Cacdzaiec. enh casswassecteds «4 124
mV. “Whe Adtinities Gl Mchimocysres) wap cans cctciatsh inntinspson yoo 126
Va Phe Struehure.0b Parcogiscuse cicdces codcaienessoacems euros 129
WAS [hic Atiained Of PONZOCISCHS: 6 cos oni a Sh dese senneenate os 130
VII. The Homologies of the Masticatory Pyramids and
Apical) Plates of Behm otdea.. 2. .cd..aditdeceeeiesoseens 131
VIII. Classification of the Cystocidaroida..................secee 132
EXe Summary. Of COnCIISIONS ys ao: quate sce > ecnigtsnasae ene ose 133
RGM AUOLO ae at. sae se ereion cae daca dcaak aa canaecos ad ctinees ask 154

I. Inrropucrion.

Tue persistence with which the Crinoidea, Echinoidea, and Stel-
leroidea have maintained their essential characters, from their first
appearance until the present time, has been often remarked and
has received very different explanations. Thus, Prof. Poulton * [8,
pp- 507-509], in his recent address to the Zoological Section of the
British Association, deduces from the fact the vast duration of that
part of the pre-Cambrian era during which the earth was inhabited.
When the paleontological record begins in the Cambrian period,
the phylum Echinoderma was already in existence. It was repre-
sented by the crinids, cystids, and stellerids, which were joined in
the Ordovician by echinids. But, in spite of their early appearance,
the oldest known members of the surviving classes may be assigned
to their respective divisions as readily as if they were perfectly-
preserved recent specimens. ‘That the different classes of echino-
derms have descended from a common ancestor is now unquestioned ;
but the search for missing links between those that still exist has
not been attended with any success. The two recent classifications
of the Echinoderma by Bell [1] and Hickel [3, p. 164] unite the
Stelleroidea and Echinoidea into one section. But the oldest known
imembers of these two classes resemble one another less than do
some of their later representatives; and we do not yet know a
single intermediate form between them. Similarly, Ttarechinus,
which of all Echinoidea most resembles the Crinoidea, came far too
late to give any evidence as to the ancestry of either class. The
only fossil echinids which give much help in linking their class with
any of the others are the Silurian Eehinocystis and Paleodiscus, of
which the structure is imperfectly known.

I prepared some notes on both genera in 1888, which the late

1 The numerals in thick type throughout this paper refer to the biblio-
graphical list on p. 134,

124 DR, J. W. GREGORY ON [Feb. 1897,

Melchior Neumayr kindly urged me to publish then. The hope,
however, of obtaining access to better specimens has delayed me from
doing so until now.

II. Hisrory oF THE GENERA.

Palcodiscus was the first established of the two genera. It was
founded by J. W. Salter in 1857 [9, p. 332, pl. ix. fig. 6] on a fossil
from the Ludlow Flags of Leintwardine. He described it as a
new starfish, a view which seemed to be established by the flattened,
pentagonal form of the fossil and its radiating lanceclate ambulacra,
which were apparently limited to one side of the body.

Echinocystis (or Echinocystites) was founded by Wyville Thomson
in 1861 [11] for some fossils from the same horizon as Palewodiscus.
He recognized that they were echinids with affinities to the cystids,
and placed Palcwodiscus as a flat member of the same family. In
this course, however, he has not been widely supported. Wright
[14, p. 35], who next referred.to Paleodiscus in 1868, accepted it as
an asterid, and Zittel, in 1879 (15, p. 453], did the same, placing
it in his suborder Encrinasterie. Neumayr, in 1881, republished
Wright's figure, and concluded [7, p. 156], ‘trotzdem tauchte kein
Bedenken gegen die Seesternnatur dieser Formen auf.’

Nevertheless, Duncan, in 1889, after examining specimens, not
only regarded Palwodiscus as an echinid, but he made it a synonym
of the genus Echinocystis [2, p. 20]. The latter genus had, mean-
while, been made by von Zittel (15, p. 480] the type of a new
order of Kchinoidea named Cystocidaroida, while Steinmann and
Doderlein [10, p. 180] used it as the basis of an order of Cystoidea
which they named Cystechinoidea. Finally, Jackson retains it
among the Echinoidea [4, p. 242]. |

Paleodiscus is therefore regarded as an echinid or an asterid,
and Echinocystis as an echinid or a cystid. As there are good
specimens of both genera in the British Museum, I propose to
describe them—ain order to attempt the determination of the class or
classes to which they belong. The specimens all come from the
Lower Ludlow Flags of Leintwardine; those of Hchwnocystrs are
casts, which yield good impressions in wax of the original animals,

III. Tue Srructure oF EcHinocysris.

The specimens representing this genus in the British Museum
are mostly crushed on to a plane, passing through the ambitus.
Sir Wyville Thomson, however, figured specimens which had been
flattened along a plane passing vertically upward through the
mouth, and these show the general form of the animal. Stein-
mann’s diagrammatic restoration is based on these figures. The
remaining points in the anatomy are illustrated by different speci-
mens in the British Museum; thus the structure of the ambulacra
and the shape and position of the madreporite are shown in
No. 40,158, and the character of the jaws in Nos. E 1256 and
40,156.

The following account of the animal has been compiled from the

Vol. 53.] ECHINOCYSLIS AND PALHODISCUS. 125:

Museum specimens, supplemented by Thomson’s figures for the
shape of the test :—

Description.—F orm spheroidal, either prolate or oblate. The test
is thin and flexible. The peristome is central on the lower surface.
The anus is protected by a group of large plates ; it is not opposite
the mouth, but opens in the posterior interambulacrum.

Ambulacra regular in width, tapering gradually to the apex.
Each ambulacrum consists of four series
of plates. ‘The plates are small, simple

: RS Fig. 1.—Ambulacral
ie The pore-pairs are biserial plates of Echinocystis.

Interambulacra of numerous ir-
regular, angular plates. In the widest
parts of the interambulacra they are about
ten in width, decreasing in number above
and below. The plates vary from trian-
gular to hexagonal. Most of the interam-
bulacral plates bear small granules, which sh pee
support short, sharp, movable spines.

Small miliary granules also occur.

Madreporite large, circular or polygonal; granular in appear-
ance, being perhaps perforated by many fine pores. It is situated
in the posterior interambulacrum, a short
distance from the meeting-point of the five Fig. 2—Pyramd from
ambulacra. masticatory apparatus

Apical plates absent. of Echinocystis, seen

Jaws large and powerful. The masti- from behind.
catory apparatus is described by Thomson
as ‘a five-sided pyramid..... composed
of pairs of strong, hollow, wedge-shaped
jaws. The apparatus consists of five
pyramids, which in general character re-
semble those of the Cidaride, although
there does not appear to have been either
rotula or brace. The symphysis between
the two half-pyramids is long, and the
epiphyses are short. Seen from the back
(fig. 2), a deep triangular depression ap-
pears to occupy most of the surface of
each half. At the free angle of each

half-pyramid there are three depressions, Fig. 3.— Distal end oy
separated by branches from the marginal pyramid of Echino-
ridge ; these depressions and ridges were cystis from the side.
probably used for muscular attachments.
The distal apex of the pyramid is very sharp
(fig. 3) : according to Thomson there were SS
strong spines situated at this point, a state-
ment which I have been unable to verify. ;

Distribution,—Leintwardine Flags, Lower Ludlow, near Leint~

wardine, Shropshire, There are two species—Z. uva and £. pomum,
but the former may be only a young stage of the latter.

126 ' DR. J. W. GREGORY ON [ Feb. 1897,

LY. Tas AFFINITIES oF ECHINOCYSTIS.

Echinocystis has been assigned to both the classes Echinoidea and
Cystoidea, and there can be little doubt that it belongs to one of
them. In order to determine in which of the two it is to be
placed, we must first consider the essential differences between
them. We are at once confronted with the difficulty that the
diagnoses of the class Cystoidea are very unsatisfactory, and it is
easier to condemn than to improve them. Bell, in 1891, when
discussing the inter-relations of the classes of Echinoderma, recoiled
from the task of drawing up a diagnosis of the Cystoidea, and hoped
[1, p. 215] that ‘perhaps a paleontologist will oblige.’ Since that
date two paleontologists have ‘ obliged,’ and we must first enquire
whether Hchinocystis is necessarily included by them among the
cystids.

vara Zittel [16, p. 148], in 1895, defined the Cystoidea as
follows :—‘ Extinct, short-stalked, more rarely unstalked Pelma-
tozoa, with more or less irregularly-arranged calycinal plates, with
the arms feebly developed, and sometimes quite absent, The
calycinal plates are frequently perforated by fine canals.’

There is nothing in this diagnosis except the word Pelmatozoa to
exclude Hchinocystis; for it is an extinct, unstalked form, with
irregularly-arranged plates, without arms, and having some of the
plates perforated by fine canals. But Lepidesthes and Melonites
both possess the same series of characters, for in these two genera
the plates protecting the body are less regular than in Caryocrinus
or Porocrinus. We have therefore to refer back to von Zittel’s
diagnosis of Pelmatozoa to see if this will exclude forms like Tvar-
echinus and yet admit Echinocystis.

The diagnosis of the Pelmatozoa [16, p. 113] is as follows ;—
‘Kchinoderma which are fixed by a jointed stem or directly by the
aboral (dorsal) side of the body, either throughout life or in youth,
A bag-shaped, calyx-shaped, or spherical capsule of calcareous plates
encloses the body-cavity. On the upper (oral or ventral) side are
the mouth and anus, as well as ambulacral vessels leading to the
mouth. At the distal ends of the ambulacral furrows of the tegmen
there usually arise jointed arms, or the ambulacral furrows continue
over the sides of the cup, and are bordered on both sides by pinnules.
The lower (dorsal, aboral) side is encompassed by one or two circles
of basal plates, which either rest on the stem or surround a centro-
dorsal plate.’ The positive characters in this definition are:—
(1) fixation at one period of life ; (2) a capsule of calcareous plates ;
(3) the occurrence of mouth, anus, and ambulacra on the upper
surface; (4) the presence of arms or pinnules; (5) the double circlet
of calycinal plates.

This combination of characters does not, however, give any test
by which we can at once say whether a certain fossil is a cystid or
an echinid. There are exceptions in regard to each character.
Thus we now know both pelmatozoic and apelmatozoic cystids
and crinoids, including forms which not only have no stalk, but no
trace of an aboral attachment. Prof. Bell remarks [1, p. 210],

Vol. 535] ECHINOCYSTIS AND PALAODISCUS. 127

‘I suppose no morphologist will be bold enough to say whether
Marsupites or the irregular Blastoids are primarily or secondarily
free forms.’ To affirm that Marsupites had a fixed stage is to push
the analogy with -Antedon to extreme and improbable limits.
Antedon retains in the adult definite traces of its early attachment ;
its central plate is called a centro-dorsal, that is, itis regarded as the
modified top stem-joint. But the corresponding plate in Marsupites
is called a dorso-central, that is, it is regarded as the central basal
plate ; therefore, ew hypothesi, Marsupites cannot have had a stem,
and its dorso-central shows no scar left from attachment by that
late.

In Uintacrinus the improbability of the members having passed
through a fixed stage is still greater, for the genus was probably
pelagic, and pelagic animals usually have free-swimming larve, even
when those of their littoral or abyssal representatives are fixed.

The second statement in the diagnosis of Pelmatozoa, namely,
that the body is enclosed in a capsule of calcareous plates, is useless,
for it is as true of echinids as of crinids.

The third point in the definition has too many exceptions on both
sides to be valid. The mouth and anus are both oral in many
echinids, whereas the anus is not on the oral side in some cystids,
such as Anomalocystis. There are no ambulacral furrows in some
cystids, such as Aristocystis, while they occur in some echinids, and
are there on the same side as the mouth and anus, as, for example,
in Scutella.

The fourth character quoted is the presence of arms or pinnule-
bearing extensions of the ambulacra in Pelmatozoa; but this would
probably exclude genera such as Aristocystis from this division of
the echinoderms.

The last structure relied on is the occurrence of calycinal plates ;
but if we accept the theory of the homology of the central, aboral
plates of echinids and stellerids with the plates of the calyx of
crinids, then these plates are better represented in some echinids
(such as Tiarechinus) and stellerids (such as Ophiopyrgus) than in
some cystids.

There is therefore no single character in von Zittel’s definitions,
of either Cystoidea or Pelmatozoa, which can serve as a certain test
as to whether a fossil is to be included among them. As of the five
characters of the Pelmatozoa Echinocystis probably lacked the first ;
as the second is equally typical of echinids and of cystids; and as
Echinocystis certainly had not the third, fourth, or fifth, then this
genus cannot be included among the Pelmatozoa as defined by
von Zittel. According to him [16, p. 174] the Echinoidea are
characterized by (1) a spherical, discoid, or oval body; (2) a body-
cavity enclosed by solid plates bearing movable spines; (3) a
ventral mouth ; (4) an anus situated in the disc, or between this
and the mouth; and (5) five ambulacra bordered by pore-series.
As Echinocystis has all these characters, it appears that von Zittel
was quite justified in restoring the genus to the Echinoidea.

A later diagnosis of the Cystoidea has been recently issued by

128 _ DR. J. W. GREGORY ON [Feb. 1897,

Hiackel. He divides the Echinoderma into three ‘ cladoms’; the
first or Monorchonia includes the Cystoidea ; the last or Pentorchonia
includes the Echinoidea. The Monorchonia includes those with
‘one pair of gonads and an unpaired dorsal genital duct; the ovoid
gland, genital sinus, and genital stolons are altogether absent”
[3, p. 164]. In the Pentorchonia, on the other hand, ‘ the gonads
are pentameral; there are five interradial dorsal genital stolons ;
there is an ovoid body with periproctal genital sinus; the mouth is
ventral. They are free, creeping on the ventral surface.’

The characters used in these diagnoses are all points of visceral
anatomy, except one which is a habit, and they cannot be easily
determined for the fossil forms. But, so far as they can be ascer-
tained, they are not invariable. The gonads are not actually
pentameral in many echinids; in most spatangids there are four ;.
in Galerites and some species of Holectypus there are also four; in
Tripylus there are but three.

It may be replied that in such echinids the ancestors had five
gonads, and the number has been reduced by secondary changes,
which need not be considered in the main diagnosis. But if a
diagnosis is to be regarded as a summary of the essential characters
of the class to which it refers, then a character which may be lost
by secondary changes ought not to enter into it; if the character
can be readily lost it is not essential. If the possession of five
gonads is an essential character of the Echinoidea, then an animal
with only three or four gonads is not an echinid.

This character is not only useless as a test-distinction between
echinids and cystids, but it certainly could not be used to separate
Echinocystis and Paleodiscus from the Echinoidea; for the pent-
ameral symmetry in these is so well marked, and the interambulacral
areas are so eapacious, that there was prokably a gonad in each
interambulacrum. We are therefore driven back to Hackel’s fuller
diagnosis of the Cystoidea on p. 72 of the same monograph. This
may be translated as follows :—‘ Echinoderma, with the essential
forms of the body bilateral-radial; with a radial anthodium [%. e.
ambulacral rosette], which is composed of several (2-5 or more)
ambulacra. Theca uniaxial or radial; it is rarely free at the
aboral pole of the principal axis, but mostly directly sessile or
fastened or fixed by astem. The tegument has rarely a flexible
scaly armour, generally a rigid plate-armour, which is composed of
very numerous polygonal small plates, irregularly arranged ; some
of the latter are frequently fused to form larger plates. The .
mouth is always central at the oral pole of the primary axis; it is
radially an oblique cleft, often circular, mostly with radial incisions
and three to five lips. The anus is always excentric, on the ventral :
side, with valvular pyramid. Between mouth and anus there is
usually a gonopore (“third aperture”), rarely also a hydropore
(‘fourth aperture”). The skeletal appendages are mostly developed
in the form of pinnules, more rarely as a peristomal circle of radial.
‘“‘brachioles,” or as a girdle of thecal arms.’

This diagnosis includes ten characters :—(1) the bilateral-radial

Peles age! - HCHINOCYSTIS AND PALAODISCUS. 129

symmetry; (2) a radial anthodium ; (3) theca uniaxial or radial ;
(4) usually fixed aborally, but sometimes free; (5) a scaly or plated
test ; (6) a central mouth; (7) an excentric anus on the aboral side ;
(8) a valvular pyramid; (9) gonopore and hydropore, when present,
situated between mouth and anus; (10) the presence of pinnules,
arms, or brachioles. This diagnosis clearly separates the cystids-
from the crinids and from the members of Hickel’s new class,
the Amphoralia ; but it does not give any very satisfactory grounds
for separation from the echinids. The Hchinoidea agree with the
Cystoidea in characters Nos. 1, 2, 3, and 5; some echinids agree
with some cystids in Nos. 4, 6, 7, and 8'; 9andi0 are not present
in all cystids, for there is no more reason to regard Aristocystis as
having pinnules, arms, or armlets than some Paleozoic echinids.
Thus the diagnosis does not yield a single constant, invariable dis-
tinction between the Cystoidea and the Echinoidea.

In order, therefore, to refer Echinocystis to its class, we have to
rely on the sum of its characters. It agrees with both cystids and
echinids in the possession of characters 1, 2, 3, 5,6, 7, and 8. In
the remaining characters, 4, 9, and 10, it agrees with typical
echinids, but differs from typical cystids. Hence it seems more
reasonable to follow von Zittel and assign the genus to the Echi-
noidea than, with Neumayr and Stcinmann, to regard it as a cystid.
The absence of calycinal plates or of any aboral attachment; the
presence of a jaw-apparatus and of articulatory spines ; the develop-
ment of an exoskeleton, which is spherical in shape, and consists of
closely-fitting plates; the occurrence of biserial ambulacral pore-
pairs; and, finally, the ventral aspect of the mouth, are all
characters in which Echinocystis agrees with the Echinoidea.

V. Tar STRUCTURE OF PALODISCUS.

Form.—Discoid, possibly subpentagenal. Test thin and probably
flexible. Mouth central on lower surface. Anus aboral, central.

Ambulacra broad on the oral surface, but gradually diminishing
in width on the aboral surface. In flat-
tened specimens they are somewhat petaloid Fig. 4.—Ambulacral
(a character, however, greatly exaggerated plates of Paleodiscus.
in Wright’s figure).

On the oral surface the ambulacral
plates are simple, thin, and bar-shaped
(fig. 4).

On the aboral surface each ambulacrum
consists of two alternate series of simple,
thin, bar-shaped plates. There are no
pores through the plates, but the podia
must have been extruded through the
sutures between them.

On the aboral surface the ambulacra are narrower (see, for
example, E 1482); and, according to Wyville Thomson, there is
a series of single pores on each side.

? A valvular pyramid occurs in Palgostoma.

Q.J.G.5. No, 209. K

130 DR. J. W. GREGORY ON [Feb. 18,7,

Interambulacra of angular, irregular, scale-like plates in
many series; at the ambitus there are ten in width in each inter-
radius.

The interambulacral plates bear numerous short spines.

Apical plates unknown, probably absent. The periproctal area
is large. Madreporite unknown.

Jaws.—According to Salter’s figure [9, pl. ix. fig. 66], the oral
armament apparently consists of an oral ring of the ambulacral
type, that is, the ambulacral constituents form 7
the prominent projections. Specimens in the Fig. 5.—Pair of
British Museum, however (such as 40,307), — half-pyramids of
show that the masticatory apparatus is very Paleeodiscus.
different from that of stellerids. It consists
(Pl. VII. fig. 5 6) of five pairs of irregularly
triangular plates; those of each pair are
joined together proximally, but are free at
the distal (7. e. the oral) ends, where they are
separated by a deep cleft. The distal ends are
expanded (fig. 5). According to Salter, some spines are situated at
the apex of each half-pyramid.

VI. Tar AFFiniries or PaLmopiscus.

The previous discussion as to the affinities of Hchinocystis has
cleared the way for the consideration of those of Palewodiscus, which
in many respects is the simpler form. It differs still more markedly
from the typical echinids, but it is even less like a cystid, and the
genus is usually assigned to the Stelleroidea, as by Neumayr,
Zittel, and Wright.

Palcodiscus resembles the stellerids in two important respects.
In the first place, the ambulacra appear in most specimens to be
limited to the oral surface ; but the case is not clear, for if Wyville
Thomson’s figures be correct, the genus is truly desmactinic.
Secondly, the ambulacral plates are not perforated by pores, at least
on the oral surface; but in the echinid Asthenosoma some of the
podia pass out through the sutures between the plates, for their
klasma-plates (see ante, p. 115) are reduced to spicular rings.

Fortunately, however, the fundamental difference between the
Echinoidea and Stelleroidea can generally be applied: in the former
the ambulacral plates cover the radial water-vascular vessel, which
is within the test, whereas in the stellerids this vessel lies in a groove
on the external side of the ambulacral plates. In Palceodiscus the
ambulacral plates are flush with those of the interradii, and in all
probability the radial water-vascular vessel was within the test.
The general characters of the skeleton are also more echinoid than
asteroid; the absence of special adambulacral plates, the occurrence
of small articulating spines, the resemblance of the interradial
perisomatic plates to those of Hchinocystis, and the character of the
masticatory apparatus, are all points which ally Palcodiscus to the
Echinoidea and separate it from the Stelleroidea.

“Vol. 53.] ECHINOCYSIIS AND PALODISCUS. 131

We must, however, compare this genus with the Cystoidea, for
there is a considerable agreement in some respects between it and
Agelucrinus. Paleodiscus is not aborally fixed; it has no pinnules,
and, in all probability, it had no calycinal plates. Of the nine
characters which Hickel assigns to the Cystoidea, Paleodiscus has
only such as are common to the Echinoidea.

The only reason for regarding it as a cystid is based on its
resemblance to Agelacrinus, which, however, is merely superficial.
In Agelacrinus the anus is on the oral surface; the ambulacra are
limited to part of the oral surface alone; there is no Jjaw-apparatus ;
the ambulacra are sinuous, and there is a peripheral zone of plates
round the disc.

Hackel is probably correct in regarding Agelacrinus' as a flattened
form of Hemzcystts, in which greater extension of the pinnule-
bearing grooves is obtained by their being twisted. Hemicystis has
no resemblance to a stellerid ; and to accept this view of the origin
of Agelacrinus means the abandonment of any fundamental affinity
between it and Paleodiscus.

There is, however, one genus, which, if correctly described by
Worthen and Miller{13, p. 335}, may be a Carboniferous representative
of either Palewodiscus or Echinocystis. According to the description
of its authors, this remarkable form has an irregular, sac-like body ;
above the mouth there is a series of plates which may represent
jaws. The name “chinodiscus was given to this fossil by Worthen
and Miller, but this term having been preoccupied by Agassiz for an
echinid, for which it is still in use, the name of the cystid may be
changed to Discocystis.

VIL. Tue Homotoeizes oF THE Masticatory PYRAMIDS AND
AptcaL Puates oF ECHINOIDEA.

From the considerations stated in the previous section, it
seems advisable to regard Paleodiscus as an echinid, allied to
Echinocystis, although not congeneric as Duncan made it. In
this case it is certainly the most primitive of Echinoidea, and
represents a condition when the ambulacral plates were only in part
perforated by pores. The presence of a masticatory apparatus is of
interest, especially as it gives us some suggestions regarding the
origin of that structure. The figures published by Lovén and his
accompanying remarks [5, pp.8 & 9, pl. iu. figs. 22 & 23], show that
while the teeth are interradial in development, the plates that form
the half-pyramids lie above the ambulacra, and are to be regarded
as ambulacral in origin. In Hchinocystis the pyramids agree with
those of Cidaris, at least in their fundamental characters; but in
Paleodiscus the structure is far more primitive. Beside the oral
ends of the ambulacra lie two strong plates, which are fixed together
aborally, but are separated by a deep groove near the mouth.

' The type-species of Agelacrinus is A. humiltonensis, Vanux. (Geol. Rep.
New York, 1842, pp. 158, 306), not A. vorticellatus, Hall, as stated by Hackel.

The genus Agelacystis founded [Hackel, 3, p. 114] ou A. hamilionensis, is there-
fore a synonym of Agelacrinus.

132 DR. J. W. GREGORY ON [ Feb. 1897,

These plates are, in all probability, ambulacral in origin, and each
plate is then homologous with the halt-pyramid of Hchinocystis. In
order, therefore, to form the pyramids of Avhinocystis, it is only
necessary to assume that the two free ends of the half-pyramids of
Paleodiscus bent inward, so that the symphysis was continued
along the whole length, instead of being limited to the aboral end.
At the same time, increase in the strength of the muscular attach-
ments led to the development of ridges and depressions on the
proximal end.

Paleodiscus therefore gives useful information as to the origin of
the masticatory apparatus of the gnathostomate echinids. For, just
as in the Stelleroidea the adoral ambulacral plates are modified to
form the ambulacra] oral projections of asterids, and the jaws (that
is, the distal portion of the syngnaths) of ophiurids, so it is probable
that the pyramids of the masticatory apparatus of echinids arose as
a modification of the peristomal ambulacral plates. As it is, how-
ever, possible that the whole apparatus was formed around the
cesophagus, and not as part of the exoskeleton, it would not be safe
to definitely claim the pyramids as the homologues of the ambulacral
oral projections of asterids and of the jaws of ophiurids.

The absence of calycinal plates is of great interest, as it appears
fatal to the theory assigning a crinoid ancestry to the Echinoidea.
The insignificance of these plates in the oldest echinids, when com-
pared with specialized forms such as Tiarechinus and Lysechinus or
larval Strongylocentrotus, shows that the so-called ‘ calycinal
plates’ are not primitive. MacBride [6, p. 436] has thrown doubt
on the homology of these plates in asterids and crinids, and Hehino-
cystis suggests similar doubts for echinids. In the early echinids
‘these plates appear as a ring round the anus. In Achinocystis the
anus opens at the centre of a circle of five valvular plates. This
Silurian echinid is followed by others in the Devonian and Carboni-
ferous, such as Palechinus and Perischodomus, in which the anus
likewise opens in the centre of five rather large plates. I see no
reason why these five circumanal plates of Palecvhinus are not
homologous with the five circumanal plates of Hchinocystis. Such at
least is by no means so far-fetched an idea as that which makes
these plates the homologues of the basal circlet of the crinoid calyx.
It is therefore at least possible, and perhaps even probable, that the
apical or so-called ‘calycinal plates’ of echinids are homologous
with the anal valvular pyramid of Cystoidea, and not with the plates
of the calyx.’

VIII. CrasstricaTIon oF THE CYSTOCIDAROIDA.

As Kchinocystis and Palaodiscus are therefore accepted as two
genera of Hchinoidea, it may be advisable in conclusion to attempt
a synopsis of the order to which they belong.

' It may be suggested that the genital pores mark out the basal circlet, and
that these pores probably opened, in Kchinocystis, round the apex, and not
round the anus. Put the connexion of these pores, as of the water-pore, with
any plates is a purely secondary feature, and cannot be used for the determina-
tion of a primary homology.

Vol. 53.] ECHINOCYSTIS AND PALHODISCUS. 133

Order Cystociwwaroiwa, Zittel, 1879.

Diagnosis.—Kchinoidea with a test composed of irregular, thin,
spine-bearing plates; the mouth is central; the anus is aboral ;
the madreporite is large and single, and occurs in the same inter-
ambulacrum as the anus (unknown on one genus); there are no
ealycinal plates; the ambulacral plates are simple, and may be
perforate or imperforate ; there is a jaw-apparatus composed of five
pyramids.

Family 1. PatmopiscipZ.

Diagnosis.—Cystocidaroida with a depressed pentagonal body.
The ambulacral plates on the oral surface are imperforate. The
anus is central.

Genus Paleodiscus, Salter, 1857 [9].

Ty pe-species.—P. ferox, Salter. Leintwardine Flags, Lower
Ludlow.
Family 2. Ecurnocysrip&.

Diagnosis.—Cystocidaroida with a spherical body. The ambu-
lacral plates are perforated by pores ; the pore-pairs are biserial, and
some demi-plates are present. The anus is excentric.

Genus Echinocystis, Wyv. Thomson, 1861 [11] (non Hall, 1867).’

Synonym.—Cystocidaris, Zittel, 1879.

Type-species.—Hchinocystis pomum, Wyv. Thomson, 1861.

Von Zittel includes the genus Spatangopsis, founded by Torell
[12, p.11] on a species named Sp. costata, as a possible cystocidarid.
Torell, however, describes the genus as having five sharp radial
coste ; and though it is possibly an echinoderm, the narrowness
of the coste would exclude it from the Cystocidaroida, whether
these radial structures are ambulacral or not.

IX. Summary or ConcLvsions.

1. The structures of the Silurian genera Paleodiscus, Salt., and
Echinocystis, Wyv. Th., are redescribed.

2. It is concluded that Echinocystis is an echinid, and not a cystid :
and that Palwodiscus is an echinid, and not an asterid.

3. The name Scolocystis is given to the cystid named Lehino-
cystis by Hall; and that of Discocystis to the form named
Lichinodiscus by Worthen and Miller.

4, In a discussion of the affinities of Hchinocystis, the two latest

' Zittel called attention to the fact that the name Echinocystis has been used
by Hall for cystids as well as by Thomson for echinids. By a slight oversight
he omitted to notice that Thomson had priority by six years, and Zittel therefore
kept the name Echinocystis for cystids and renamed Thomson's genus Cysto-
cidaris. Although this has been more than once pointed out (¢.g. Duncan, 2,
p- 20), Hackel retains Hchinocystis for the cystid. To save further confusion,
I propose the name Scolocystis for this cystid (from ox@dos, a thorn).
Acanthocystis, also accepted by Hackel, has long been preoccupied among
Protozoa by Carter. Hall’s date is sometimes given as 1864; some advance
copies of the Report were issued in 1865, but it was not published until 1867.

134 DR. J. W. GREGORY ON [ Feb. 1897,

diagnoses of the Cystoidea are considered, and it is con-
tended that they do not enable us to draw any sharp line of
distinction between the Cystoidea and the Echinoidea. __

5. It is shown that the masticatory apparatus of Paleodiscus and
Echinocystis explain the origin of that structure in gnatho-
stomate echinids.

6. It is suggested that Hchinocystis renders probable the homology
of the so-called ‘calycinal plates’ of Echinoidea with the
plates of the valvular pyramid of Cystoidea, and not with
the calyx-plates.

X. LIrERATURE,

1. Buxt, F. Jurrrey. ‘On the Arrangement and Inter-relations of the Classes
of the Echinodermata,’ Ann. Mag. Nat. Hist. ser. 6, vol. viii. (1891)
pp. 206-215.
2. Duncan, P. M. ‘A Revision of the Genera and Great Groups of the
Hehinoidea,’ Journ, Linn. Soe., Zool. vol. xxiii. (1890) pp. 1-311.
3. Hacker, E. ‘Die Amphorideen und Cystoideen. Beitrage zur Morpho-
logie und Phylogenie der Echinodermen,’ Festschr. Gegenbaur, 1896,
vol. i. pp. 1-180. pl. iv.
4. Jackson, R. T. ‘Studies of Palechinoidea,’ Bull. Geol. Soc. Amer.
vol. vii. (1896) pp. 171-254, pls. ii-ix.
5. Loven, 8S. ‘ Echinologica,’ Bihang k. Svensk. Vet.-Akad. Handl. vol. xviii.
pt. iv. no. 1 (1892), 74 pp., 12 pl.
6. MacBrivg, E. W. ‘The Organogeny of Asterina gibbosa, Proc. Roy. Soc.
vol. liv. (1894) pp. 431-486.
7. Neumayr, M. ‘ Morphologische Studien tiber fossile Echinodermen,’ Sitz.
k. Akad. Wiss. Wien, vol. lxxxiv. pt. i. (1881) pp. 143-176, 2 pl.
8. Poutton, E. B. Presid. Addr. to Sect. D, Brit. Assoc. (L’pool Meeting),
‘Nature,’ vol. liv. (1896) pp. 500-509.
9. Satrer. J. W. ‘On some New Palzozoic Starfishes,’ Ann. Mag. Nat.
Hist. ser. 2, vol. xx. (1857) pp. 3821-334 & pl. ix.
10. Sremmann, G., & Dopertem, L. ‘Elemente der Palaontologie,’ pt. i.
(1888) pp. 1-336.
11. Tuomson, Wyvitte T.C. ‘Ona New Paleozoic Group of Echinodermata,’
Edin. New Phil. Journ. vol. xiii. (1861) pp. 106-117 & pls. ii1., iv.
12. Torey, Orro. ‘ Petrificata Suecana Formationis Cambric,’ Acta Univ.
Lund. vol. vi. (1869) no. viii. 14 pp.
13. Wortuen, A. H., & Minune, 8. A. ‘ Descriptions of New Carboniferous
Echinoderms,’ Pal. Illinois, vol. vii. (1883) pp. 327-838, pl. xxxi.
14. Wricut, Tu. ‘Monograph of the British Fossil Echinodermata of the
Oolitic Formations, vo]. 1i—‘ The Asteroidea and Ophiuroidea,’ Pal.
Soc. 1863-1880.
15. Zirrer, K. ‘ Handbuch der Palaontologie,’ vol. i. pt. iii. (1879).
16. ZirreLt, K. von. ‘Grundzige der Palaontologie.’ (1895.)

EXPLANATION OF PLATE VII.

Fig. 1. Pedinothuria cidaroides, sp. n., B.M. 34.724.—Figs. 1a, 6, and e¢, the
test seen respectively from below, from the side, and from above.
x 3 diam.

Fig. 1d. Outline. Natural size.

Fig. 2. An interambulacrum of the same. X 5 diam.

Fig. 3a. An ambulacrum of the same. X 5diam. Figs. 36, c, and d. Parts
of an ambulacrum, showing arrangement of the plates.

Fig. 4. Echinocystis pomum, Wyv. Th.—A specimen in the British Museum,
from the Leintwardine Flags, showing the aboral surface, with
madreporite and ambulacra. Natural size.

Fig. 5. Palgodiscus ferox, Salt. _A specimen in the British Museum, from the
Leintwardine Flags.—Fig. 5a, oral side; 56, the oral armament of
the same specimen, from a wax mould. Natural size.

Weald 3: | ECHINOCYSTIS AND PALXODISCUS. 135

Discussion (ON THE TWO PRECEDING PaPERs).

Mr. F. Baruer inclined to accept the homology of the anal
pyramid of Echinocystis with the anal pyramid of cystids on
the one hand and the proximal apical plates of echinoids on the
other, and agreed that it would prove entire absence of homogeny
between the apical system of echinoids and the calycal system
of crinoids and certain cystids. It was not, however, fair to
say that Lovén, Carpenter, and Sladen had derived Echinoidea from
a crinoid ancestor: this theory was a fiction of its opponents—
e.g. Semon and the Sarasins. What had been maintained was
that the homologue of the calycal system could be traced in all
classes of Echinoderma, and therefore had been possessed by their
common ancestor. But the rejection of this theory did not imply,
as Dr. Gregory had seemed to suggest, the rejection of the hypo-
thesis that the quinqueradiate symmetry of Echinoderma was due to
a fixed mode of life. In this group it could not be due to a free-
swimming existence, since free-swimming forms were secondary
developments; a creeping existence, again, produced antero-poste-
rior elongation. Nor was the possession of perradial ambulacra,
whether epithecal, hypothecal, or exothecal, the common heritage
of the whole phylum Echinoderma from a ‘ Pentactwa’ ancestor.
The simplest cystids—Aristocystide—showed no trace of radial
symmetry in the arrangement of plates, nor of any extensions from
the circumoral water-ring, nor of ciliated grooves leading to the
mouth. Whether Lchinocystis were placed in the Cystidea or
Kchinoidea was a mere question of names; but while its relation
to the Echinoidea was clear, its relations to the Cystidea were still
veiled. Echinocystis, in common with other echinodermata, must
have descended from simple forms like the Aristocystide, and the
quinqueradiate extension of its water-system must have arisen
during a period of fixation somewhere in the race-history. This
habit of life must have acted on hypothecal extensions from the
water-ring, communicating with the exterior through pores between
the plates, as in Agelacrimus and similar fixed forms, a position
retained in Paleodiscus; ambulacral pores had no connexion with
the scattered cystid diplopores. The position of the madreporite
might throw some light on the question: information as to this, or
any suggestions by the Author as to the probable line of ancestry,
would be of much interest.

The Rev. J. F. Buaxe referred to the diagrams drawn by the
Author showing on one side a row of simple ambulacral plates,
and on the other a series of primary and demi-plates, and enquired
whether there was any paleontological evidence to show that,
as described by the Author, the demi-plates were diminished
primaries pushed aside by the growth of the others, or, in the
reverse order, growing plates which were destined to become
ultimately equal to the other primaries, and thus the whole struc-
ture should pass from the complex to the simple.

The Prestpent asked the Author whether he had had an oppor-
tunity of examining the supposed echinoid forms found some years

136 ECHINOCYSTIS AND PALHODISCUS.. [ Feb. 1897.

ago by Dr. Torell in the Cambrian rocks of Sweden, apparently the
oldest at present known.

The AvurHoR replied that the Spatangopsis of Torell may be an
echinoderm, but it is not an ally of the Cystocidaroida. In reply.
to Mr. Blake, he said that the development of the echinid ambu-
lacral plates is from the simple to the complex. He had not said
that Lovén, Carpenter, or Sladen had asserted the development of
Echinoidea from Crinoidea, but only that their homology of the
apical plates with the calyx-plates of the Pelmatozoa suggested
the origin of the Echinoidea from that group of echinoderms of
which the Crinoidea are the only living representatives. He had not
stated it as his opinion that a pentaradiate water-vascular system
was an essential character of an echinoderm, but that this view
was assumed by those who argued that the pentaradiate symmetry of
echinoderms was due to fixation. He agreed with Mr. Bather that
this character was not essential. The madreporite of Hchinocystis
is not at the apex, but in the posterior interambulacrum.

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Wot. 53.) GLACIAL PHENOMENA OF PALHOZOIC AGE. 137

10. On Gractat Poenomena of Patmozorc AGE in the VARANGER
Frorp. By Avprey Srrawan, Esq., M.A,, F.G.8. (Read
January 20th, 1897.)

[Puates VIII-X.]

An expedition to Vadsé in the Norse King having been organized
to observe the total eclipse of the sun in 1896, I took advantage of
it for the purpose of examining as much of the Varanger Fiord as
time would permit. I had two objects more especially in view:
firstly, a visit to a section described by Dr. Reusch as showing a
conglomerate of glacial origin intercalated in rocks of reputed
Paleozoic age!; and, secondly, an examination of the raised beaches
and glacial phenomena of the region. The remoteness of the fiord
probably accounts for the fact that the remarkable section dis-
covered by Dr. Reusch had remained unvisited by any other
geologist, and for the rejection of his conclusions in the face of
most convincing evidence.

The section in question lies about 26 miles farther up the Fiord
than Vadsd, where the Norse King lay, and for my opportunities
of visiting it I was indebted to Mr. R. R. Pirrie, who most
generously allowed me the use of one of his small steamers
for that purpose. I had also the advantage of the assistance of
Mr. Charles Upton and Mr. E. Dickson, F.G.S., in examining the
section.

The Varanger Fiord runs nearly east and west, and is about
50 miles long, with a breadth of 12 miles at Vads, and of 3 to 7
miles west of that town. At its western extremity it divides into a
northern branch, known as the Meesk Fiord,* and a southern branch,
at the head of which lies the Lapp settlement of Karlbotn. The
fiord itself has been excavated along the junction of the crystalline
rocks with a sedimentary and little altered formation known as the
Gaisa* system, and consequently presents a marked contrast in the
scenery of its northern and southern shores. The former, occupied
by the Gaisa Beds, presents a succession of desolate moorlands,
rising gently to a height of 600 or 800 feet, or even 1000 feet
inland ; the southern shore, on the other hand, is diversified by the
rugged outlines characteristic of the older rocks, and is intersected
by numerous deep fiords of the usual Norwegian type.

The boundary-line between the two systems is shown on Keilhau’s

1 Norges geologiske Undersdgelse: ‘Det nordlige Norges Geologi,’ 1891,
pp. 26-34. See also Aarbog for 1891, p. 78.

? It may be worth noting here that good quarters are obtainable at Nyborg,
on the northern shores of the Mesk Fiord, and that an excellent road leads
thence to Vadso (30 miles) in the one direction and to the Tana River (9 miles)
in the other.

3 The term ‘ Gaisa,’ in Finnish, is equivalent to ‘ Fjeldtop’ in Norse, which,
literally translated, is ‘ mountain-top.’

2. J.G.8, No. 280. L

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Vol. 53.] GLACIAL PHENOMENA OF PALHOZOIC AGE, 139

map of Norway (1844), and on Dr. Dahll’s map,! to strike the
shore of the fiord in the peninsula known as Kvalnes, and to run
thence to Karlbotn, and so westward to the Tana River near
Polmag. I found a good exposure of the junction a short distance
north-east of Karlbotn, in the direction of Bigganjargga. On the
foreshore the granitic rocks rise into view for a few yards in the
form of a low boss, upon, and closely adherent to, which lay a few
inches of hard sandy material. Immediately upon this came well-
bedded grits, consisting of disintegrated granitic débris redistributed
as a sediment, which passed up into sandstones of the usual Gaisa
type. On one side of the boss a small hollow, due to a pre-Gaisa
joint or small fault in the granitic rocks, had been filled up with a
coarse conglomerate before being overspread by the Gaisa sediments.
The conglomerate consisted of partially-rounded blocks of granitic
rocks ranging up to 6 inches in diameter. The surface of the
boss, like all the other rock-exposures of the neighbourhood, was
strongly glaciated, but neither in this nor in any other respect was
there evidence of contemporaneous ice-action. The section proved
conclusively, however, that the crystalline rocks had been meta-
morphosed and subjected to vast denudation before the Gaisa epoch
commenced, the relations of the two systems rather forcibly bringing
to my mind those of the Carboniferous strata to highly-altered rocks
as seen in parts of our own country. Viewed from the hillside above,
the boundary-line between the two was clearly marked out in its
westward course towards the Tana River by the same scenic features
as those which distinguish the two sides of the Varanger Fiord.

These basement-beds of the Gaisa system pass up, in a few feet,
into well-bedded quartz-grits, often containing quartz-pebbles, and
interstratified with red shales. Strata of this character form the
promontory which separates the two arms of the Varanger Fiord,
the grits giving rise to frequent little scarps separated by swampy
hollows, in which disintegrated shale is occasionally visible. They
dip at a gentle angle northward, and in proceeding in that
direction, and presumably therefore ascending in the series, we
noticed less conglomerate, but more shale and sandstone, frequently
of aredor purplish tinge. The fine section in the precipitous ravine
of the Meskely, 2 miles east of Nyborg, shows upwards of
100 feet of alternations of grey grits and red or mottled shales, in
beds of 1 to 2 feet in thickness. The strata here have been thrown
into sharp folds running E.N.E., a somewhat unusual feature in this
neighbourhood, for the Gaisa Beds, wherever else I saw them,
showed but little disturbance.”

At Vads6 a low cliff, extending for some distance westward,

* «Geologisk Kart over det nordlige Norge, udarbeidet efter Foranstaltning af
den Kongelige Norske Regjerings Departement for det Indre,’ Kristiania, 1866-
1879. Iam indebted to Mr. W. H. Hudleston for the interesting fact that the
position of the boundary was correctly fixed by Keilhau more than 50 years
ago.

oe section is figured in Reusch’s ‘Geology of Northern Norway’ 1891,
p. 30.

L2

140. MR. A. STRAHAN ON GLACIAL PHENOMENA OF [May 1897,-

consists of irregularly-bedded sandstones with grey and purplish
shales. The sandstones occur in the most irregular manner and.
wedge in so suddenly as almost to resemble included masses; they
contain also fragments of shale more or less rolled, and in this and
other respects indicate that deposition alternated with erosion under
the influence of variable currents. The rather bolder cliff on the:
southern side of Vadso Island presents crags of grey quartz-grit-
separated by upwards of 20 feet of fine red sandstone, current-
bedded in thin lamine. I saw also on the hillsides boulders which
I believe to have been derived from the Gaisa rocks, in which frag-
ments of dolomite were abundant.

In all these respects the Gaisa Beds present only such features
as are common to rocks of the type of the Wealden, Trias, Coal.
Measures, or Old Red Sandstone, and give no hint of the action
of ice. But on visiting the section near Bigganjargga,' referred
to by Dr. Reusch, I found a deposit of which I have seen no-
counterpart in any of those formations. The cliff there rises from:
the shore in a succession of rock-ledges, the strata being nearly
horizontal and free from surface-deposits. In the lowest ledge,
just above high-tide mark, a lenticular mass of darker rock inter-
calated between the ledges of sandstone at once arrests the atten--
tion, even as seen from the deck of a steamer (Pl. VIII). The
mass wedges in abruptly, and at a distance of about 4 yards from
the point of its first appearance attains a thickness of 8 feet..
Thence it runs for about 70 yards at the foot of the cliff, until.
the gentle dip carries it beneath the sea, the thickness nowhere
exceeding about 10 feet. Its base is remarkably straight, for a
reason given hereafter; but its upper surface undulates as the
thickness of the mass varies, and on these undulations the overlying
sandstones have.been tranquilly deposited in such a way as to level--
up the irregularities, some of the beds thinning away against the
sloping sides of the mass (Pl. IX), while others overtop it and
extend continuously across it.

Having been deposited on a sloping surface, these strata vary in
thickness and are slightly inclined, but in the overlying sediments:
all such irregularities of deposition gradually disappear, and a few
feet up in the cliff the bedding runs evenly and uninterruptedly over
the site of the buried lenticle. For an inch or two at their base
the sandstones in contact with the buried mass contain material
washed up from its surface.

The mass itself is a boulder-rock quite unlike any of the Gaisa-
sandstones or conglomerates which I saw elsewhere. It is referred.
to by Dr. Reusch as a conglomerate, but from the fact of its being
neither stratified nor waterworn I prefer to avoid the use of that
term. It may be described as a dark-bluish or ashy-grey friable
rock, composed of a heterogeneous mixture of grit, sand, and clay

1 The section is exposed about 2 miles north-east of the two or three Lapp:
huts known by that name, and about a mile west of the Island of Suolo

shown on the map (p. 138).

Quart. Journ. Geol. Soc. Vol, LIII. Pl.

CYcADEOIDEA GIGANTEA, sp. nov.

Sar

wee eee

ol ee

Quart. Journ. Geol. Soc. Vol. LIII. Pl. II.

Fig. 2.

CYCADEOIDEA GIGANTEA, sp. nov.

is

Quart.Journ.Geol.Soc Vol LI PL IL

,Cambridge.

3 OTL

ls

Edwin Wi

A.C.Seward del.

CYCADEOIDEA, MACROZAMIA ETC.

Quart.Journ.Geol. soc. Vol. LIL. Pl IV

,Cambridge.
J

iSOn

Edwin Wil

BS.

ih

CYCADEOIDEA AND BENNETTI

A.C.Seward del.

A.C. Seward del Edwin Wilson,Ca mbridge ,
CYCADEHOIDEA.

- Vol. 53.] PALMOZOIC AGE IN THE VARANGER FIORD. ‘141

-of all degrees of coarseness, and containing boulders ranging up to
2 feet in length scattered through it. Though quite unstratified, it
shows here and there a slight schistose! structure. The included
‘boulders, which are of all shapes and lie at all angles, consist
principally of red and grey granites, and of quartz-grits resembling
those of the Gaisa formation. I did not succeed in finding any
striated blocks, but the fact that the matrix has been hardened and
adheres closely to the boulders prevented me from examining more
than two or three in the limited time at my disposal. From a similar
boulder-rock at Mortensnes, however, which I unfortunately missed
seeing, Dr. Reusch describes and figures well-glaciated blocks ot
dolomite.”

Before quitting this part of the subject I would point out that
the form of the intercalated mass of boulder-rock, as well as the
fact that fragments of it occur in the base of the overlying strata,
indicate that it underwent denudation before it was buried. Not
improbably it extended considerably farther west than the present
limit, as indeed is suggested by the extension of the striated
pavement in that direction. It is easy to conceive that the whole
mass might have been washed away, excepting only the larger
boulders, in which case the glacial episode would have been recorded
only by the presence of large erratic blocks embedded in Gaisa
quartzites. Some of the erratic-bearing beds in other parts of the
world, subsequently alluded to, possibly originated in this way.

The boulder-rock rests on a regularly-bedded sandstone of the
usual type, and has been weathered back so as to expose several -
square yards of the remarkably even surface of that rock. The
platform thus exposed is not only smoothed, but conspicuously and
characteristically striated (Pl. X). The scratches can be followed
in some cases for 2 or 3 yards, not only up to the foot of the little
cliff of boulder-rock, but under it, a fact of which I made certain by
wedging out some masses of that material, and exposing a fresh
portion of the platform. This striated pavement is visible for a
short distance beyond the point where the boulder-rock thins out, as
already mentioned. Three sets of strie can be detected, the strongest
running N. 30° W., asecond, less marked, ranging N. 70° W., while
a few occur with the direction N. 10° W. Though strongly scored, as
well as smoothed, the sandstone does not seem to have suffered much
erosion, for the boulder-rock rests upon the same bed throughout
the section. The sandstone is traversed by a few irregular joints,

1 [By the word ‘schistose’ reference is made merely to an obscure fissile struc-
ture developed here and there in the rock, in consequence of which it splits more
readily along certain curving, nearly horizontal planes than in other directions.
The microscope shows, as I am informed by Mr. Teall, that the rock is quite
uncrushed, and has not been subjected to such movements as would have taken
place if the striated surface had been part of a thrust-plane.—Jan. 29th, 1897. ]

* ‘Geology of Northern Norway,’ 1891, pp. 30 et segg. It is worth noting
that stones in a conglomerate have been known to acquire scratches by sub-
sequent movements in the rock, whether by squeezing in a gritty matrix or by
grinding against one another. Dr. Reusch’s figures, which are reproduced
from photographs, in no way recall such markings, but represent boulders with
ithe shape and striation characteristic of ice-action.

142 MR. A, STRAHAN ON GLACIAL PHENOMENA OF [May 1897,

the lines due to which, however, on the striated platform bear no
resemblance to glacial groovings. The strie have, beyond ques-
tion, been cut into that surface independently of any structure
possessed by the rock, and are in all respects characteristic glacial
markings.

From the character of the markings it is necessary to suppose
that the sand of which the quartzite consists must have become
consolidated before the ice advanced over it, although it must
apparently have been newly formed at that time. I suggest, how-
ever, that it may not have been literally the latest deposit, but that
it may have been buried, more or less consolidated, and only brought
into contact with the ice by the removal of all overlying sediment
that had not become compacted.

The evidence detailed above seems to leave no room for doubt:
that we have here an intercalation of a true glacial till’ in the
Gaisa formation, for it provides an answer to every alternative theory.
Three possible explanations of the section had suggested themselves:
to me before my visit to the spot :—

(1) That the striz had been made during the Glacial Epoch or
subsequently.

(2) That the till had been forced in between the ledges of
sandstone during that epoch.

(3) That the till was not a glacially-formed deposit, but a
crush-conglomerate or a fault-breccia, and that the striated
surface beneath it was the floor of a thrust-plane.

The first of these is disposed of by the fact that the strice
unquestionably pass beneath the till.

The second is negatived by the fact that the till existed before
the sandstones above it were deposited, for the obstruction offered
by it to the even distribution of the sand, until it was finally buried,
is perfectly clear.

The third, which had seemed the most probable, is equally
untenable. A crush-conglomerate or a fault-breccia is made up:
of the fragments of the strata which it traverses; the till, on the
contrary, consists largely of boulders and débris of granitic rocks,
which can nowhere form part of the Gaisa formation. Nor does
the striated floor present any of the features of a fault or thrust-
plane, for the markings are confined to the one surface, and do not
occur along more than one plane, as happens with slickenside, nor is
there any indication of shattering in the rocks either in a direction
parallel to the grooved surface or in any other. That such a fault
or thrust-plane should exist here is highly improbable, for there is
no sign in the neighbourhood of such disturbance as the theory
demands. Lastly, the relation of the till to the sandstones above
it is alone sufficient to disprove the hypothesis.

1 The name ‘till’ is used here, not as indicating the presence of clay, but as
descriptive of a material formed by the mixing together by glacial action of
the débris of rocks of any composition.

Vol, 53.] PALMOZOIC AGE IN THE VARANGER FIORD. 143

Under these circumstances I accept without hesitation Dr. Reusch’s
conclusion that the phenomena are due to glacial action, and that
they were produced contemporaneously in the Gaisa formation.

The determination of the age of the Gaisa rocks now became an
object of importance, and a diligent search for fossils was made by
myself and other members of the expedition, but unfortunately
without result. Up to the present no fossils have been recorded
from these rocks, and in their absence we have to fall back upon the
stratigraphical relations of the system to other groups in the north
of Norway. Of these [had no opportunity of judging, and therefore
abstract all that is at present known on the subject from the publi-
cations of the Norwegian geologists. According to Dr. Dahll, the
Gaisa rests unconformably upon an older system known as the
Raipas, which also is later than the metamorphism of the crystalline
rocks, and, like the Gaisa, unfossiliferous. The Raipas is regarded
by Dr. Dahll as representing Devonian, and the Gaisa as being either
Trias, Dyas, or Carboniferous.'. Dr. Reusch, on the other hand,
throws doubts on the supposed unconformity between the Raipas
and Gaisa, and compares the whole sedimentary group with the
Sparagmite formation of Southern Norway.* This formation, which
is described as consisting largely of felspathic sandstones and quartz-
ites, also rests upon a denuded surface of highly-metamorphosed
rocks, and is overlain by strata containing the Olenellus-fauna, a
fact which proves that it is of Cambrian or earlier age. Dr. Nathorst
expresses an opinion that Dr. Reusch’s view that the Gaisa is of the
same age as the Sparagmite is more probable than that of Dr. Dahll.’
So far, therefore, as our information goes at present, the Gaisa
Beds may be of about the same age as the basal Cambrian quartzite,
or they may be even as old as the Torridon Sandstone.

In general lithological characters the Gaisa Beds belong to the
type of the great continental formations; the scarps of quartz-grit
with intervening red sandstones or red shales reproduce the appear-
ance and scenery of ‘much of both the Torridon Sandstone and the
Old Red Sandstone, while the irregularly-bedded sandstones and
shales of the cliff near Vads6 so strongly recalled parts of the Coal
Measures that I was in constant expectation of finding plant-
remains.* The red sandstones could no less appropriately be matched
by parts of the Bunter. They all belong, in fact, to the type pre-
vailing in those formations which have been the first to be deposited
at the close of a great continental epoch. Among the characteristics
common to such formations may be mentioned, firstly, that they rest
upon a deeply-denuded surface of much older rocks; secondly, that
they originated in a copious supply of more or less raw detritus—that
is, of detritus which had neither been completely decomposed nor
ground down to the last stage of fineness, and which may even

1 ‘Geology of Northern Norway,’ 1891, p. 197. 2 Ibid. p. 199.

° «Geology of Sweden,’ by A. G. Nathorst, 1894, p. 153.

* It is interesting to note here that upwards of 230 feet of productive Coal
Measures intervene between two erratic-bearing series in New South Wales.

144 MR. A; STRAHAN ON GLACIAL PHENOMENA OF [May 1807,

at times be traced to its source among the older rocks; thirdly,
that deposition was not only unequal but alternated with erosion,
leading to fragments of one bed being included as pebbles in another ;
fourthly, that they rarely contain marine organisms, or such strata
as usually compose marine formations, while on the other hand
drifted plant-remains are not uncommon; fifthly, that such lime-
stones as occur consist, when unaltered, of amorphous carbonate of
lime and not of organic remains; while, lastly, there is common to
all a tendency to a red colour. All these characteristics may be
taken as indicating the proximity of large land-areas, and it is in
rocks of this type, if anywhere, that evidence of the existence of
land-ice might be expected to be preserved.

We are here reminded that ice-action was called in so long ago
as 1855 by Ramsay’ to account for certain characters in the Old
Red Sandstone and the Permian, and though the evidence on which
he relied has since been proved by Mr. Wickham King to have
been insufficient, the idea has been revived of late years by Mr.
Oldham. More recently Dr. Hicks found evidence of glacial action
in the Cambrian rocks of Wales, not only in the presence of large
boulders, but in the enormous thickness of beds devoid of marine
life,? and points out that ‘at no time since, unless in the Glacial
period, does there seem to have been so much land in the higher
latitudes, and it is, therefore, reasonable to suppose that in the
earlier stages at least of the epoch the climate was one of great cold’
(op. cit. p. 252). It is especially noteworthy that the Gaisa Beds
appear to be approximately of the same age as the rocks referred
to by Dr. Hicks.

In the formations in other parts of the world in which glacial
phenomena occur we find a repetition of the same general charac-
teristics. Most of those described consist of sandstones, mudstones,
and conglomerates of great thickness, and showing, in the inter-
spersal of great erratics, evidence of the prolonged action of ice,
though in some cases striated pavements and deposits of the type of
Boulder Clay have also been observed. They, therefore, differ
from the Gaisa Beds, which at present are known to contain only
an occasional glacial episode, during which there seems to have been
a sudden and possibly brief invasion of the water by land-ice, though
the sediments above and below contain no erratics or any other hint
of glacial action. But both to the Gaisa and the other formations
there seems to be common a general absence of marine organisms or
of strata of open-sea origin. They rarely contain any fossils save
plant-remains, and in this and other respects approximate to the
same type as the great continental formations alluded to above.

Evidence of glacial action in such formations has been discovered
in Australia by Selwyn,° in Tasmania, in India by Dr. Blanford, in

1 Quart. Journ. Geol. Soc. vol. xi. (1855) p. 185. See also R. D. Oldham,
abid. vol. 1. (1894) p. 463.

2 Geol. Mag. 1876, p. 157; zbid. 1880, p. 488.

8 The latest account of these glacial beds, together with references to the
previous literature, will be found in a paper by Prof. Edgeworth David, Quart.
Journ. Geol. Soe. vol. lii. (1896) p. 289.

Vol. 53.] PALHOZOIC AGE IN THE VARANGER FIORD. 145

South Africa by Dr. Sutherland, and in South America, and though
their exact age has generally been in doubt, in consequence of
their poverty in fossils, many of them have been assigned to a
late Carboniferous period with considerable certainty. Others are
described as being of Permo-Carboniferous age, an expression which,
so far as Western Europe is concerned, is extremely indefinite ;
while in yet a few cases their unconformable relations to strata
bearing Carboniferous fossils suggest an early Mesozoic age." But
the fact that several of the glacially-formed rocks in these tropical
and subtropical regions belong to approximately the same date
seems extremely suggestive of a temporary but general change
of climate towards the close of the Carboniferous epoch, as sup-
posed by Feistmantel.* It will be noted, however, that the only
example hitherto recorded from Northern Europe or Asia belongs,
if Dr. Reusch’s correlation proves to be correct, to a vastly earlier
period.

The section which I have described lies in latitude 70° 8’, and its
situation so far north may be taken into consideration in attempting
to account for the glacial episode. At the same time geographical
situation does not explain all the evidences of past climates that we
possess, for not only do the Australian, Indian, and African glacial
deposits lie in what are now tropical and subtropical regions, but
rich fossil floras and faunas have been obtained in younger forma-
tions far north of the Varanger Fiord. Nor can the phenomena be
explained by supposing the existence of snow-covered mountain-
ranges, for glaciers, however large they might be, would not reach
the sea-level and distribute boulders in marine formations in or
near the tropics. The Gaisa Beds, so far as I saw them, do not
suggest the immediate neighbourhood of a mountain-region, for such
conglomerates as they contain are neither coarse nor plentiful. The
facts tend rather to indicate a temporary deterioration of climate
both in this and the other instances recorded, but how far the Gaisa
episode was universal (so far as the northern part of the globe
is concerned) it must be left to future investigations to determine.

PostscRIPt.

[In consequence of the importance of the point raised in the
discussion by Sir Archibald Geikie, thin sections of the boulder-
rock and underlying quartzite have been cut, for the purpose of
ascertaining the cause of their hardness. The sections show that
the grains of sand which form a large proportion of the matrix of
the boulder-rock, as well as those composing the quartzite, have been
enlarged by the deposition of secondary silica in optical continuity
with the original grains. The induration of the two rocks was
therefore due to the same cause, and presumably took place at the

1 Thus the Dwyka Conglomerate and associated Karoo Beds of South Africa,
as I am informed by Mr. Gibson, rest quite unconformably upon the Zwarte-
bergen Quartzite, in which Mr. Sawyer has obtained Carboniferous fossils,
Trans. Fed. Inst. Min. Eng. vol. ix. p. 365.

? Mem, Geol. Surv. N.S.W. (1890), Pal., No. 3, p. 181.

146 GLACIAL PHENOMENA OF PALMOZOIC AGE. [May 1897,

same time. It follows that the quartzite was not hardened by the
deposition of the silica until after the deposition of the boulder-rock.
For this observation I am indebted to Mr, G. Barrow.

One of the slices referred to traverses the junction of the boulder-
rock and quartzite, and shows that the grains composing the
quartzite project into the overlying boulder-bed and have not been
cut or broken through; such as were removed in the process of
glaciation were torn away bodily and incorporated in the boulder-
rock. On the other hand, when the quartzite in its present condi-
tion of induration is broken, many of the grains seem to be broken
across—owing to the firmness with which they are held in the
matrix. This observation, which is due to Mr. Teall, proves that
the quartzite is harder now than at the time of its glaciation. In
one of my specimens, moreover, a small chip of a granitic rock lies
embedded in the surface of the quartzite, as though it had been
forced in before that rock was hard.

It seems that even an incoherent sand is capable of retaining
glacial groovings, for I am informed by Mr. Clement Reid that the
base of a boulder-clay resting on soft sand on the Norfolk coast
showed ridges which were obviously casts of furrows in the surface
of the sand below. A suggestive observation has been made also
in Alaska by Mr. Harry Fielding Reid,’ who states that ‘the
alpine end of the Charpentier Glacier rests on gravels. In the
hundred feet or more between the glacier and Hugh Miller Inlet
the gravels are streaked with uniform, straight, parallel grooves, a
foot or two apart, which looked as if they had been ploughed out.’ A
further suggestion, made by Mr. Belinfante, that the sand may have
been frozen when the ice passed over it, is deserving of considera-
tion.—January 29th, 1897.]

1 Sixteenth Annual Report U.S. Geol. Surv. (1894-95) p. 452.

PLATES VIII-X.

Views of cliff near Bigganjargga, showing the contemporaneous Boulder Clay.
interbedded with the Quartz-grits.

[For the Discussion, see p. 153. |

Quart. Journ. Geol. Soc. Vol. LIII, Pl. VIIL.

NEAR BIGGANJARGGA, LOOKING EAST.

) ConTemPoRANEOUS BovtpER Cray Between Quartz-erits (Garis Bens).
. [Q = Quartz-grits; B = Boulder-rock.]

Quart. Journ. Geol. Soc. Vol. LIII. Pl. IX.

NEAR BIGGANJARGGA, LOOKING EAST.
Quarrz-cRits (Ga1sA Brps) BEDDED ON AND AGAINST ConTEMPORANEOUS BouLpER Otay.
The camera-case lies upon Boulder-rock in place.
[Q = Quartz-grits ; B = Boulder-rock.]

Quart. Journ. Geol. Soc. Vol, LIII. Pl. X.

NEAR BIGGANJARGGA, LOOKING WEST.

ConTEMPORANEOUS BouLpER CLAY, RESTING ON A G@LACIATED SURFACE OF QUARTZ-GRIT, AND OVERLAIN BY
~ Quartz-arit (Gaisa Bens).
ee [Q = Quartz-grits ; B = Boulder-rock ; QG = Glaciated Quartz-grits.]

. aks ‘ 4 in

e a
a een cane re mee a ee mene me eS ie

Vol. 53.] RAISED BEACHES OF THE VARANGER FIORD. 147

11. The Ratsep BracHes and Gractat Depostts of the VARANGER
Frorp. By Avsrey STRAHAN, Esq., M.A., F.GS. (Read
January 20th, 1897.)

Tue raised beaches of the Varanger Fiord have frequently been
noticed.| Though readily recognized all round Northern Norway,
they are particularly well developed on the less precipitous coasts
formed by the Gaisa rocks. In the immediate neighbourhood ot
Vadso, the long slopes leading up to the moorlands of the interior
can be seen from the sea to be diversified by a sticcession of
terraces, too numerous to count, and lying one above the other up
to a height of nearly 300 feet above the present shore. On closer
examination’ these terraces are found to consist of shingle and sand,
piled up here and there into characteristic beach-ridges, and
enclosing behind them a number of shallow lakes or peat-bogs.
Where the form of the ground permits they extend a considerable
distance inland, and change the character of a large tract of country.

Though in every locality that I visited some of the intermediate
beaches were more pronounced than others, I was not able to trace
on such banks for more than a short distance, or to show that they
occurred at the same level in different parts of the fiord. They
seem rather to have been due to wave-action having been more
energetic first in one place, then in another, as the form of the coast
varied with the change of level. On the other hand, the upper
limit of the series of beaches could be traced without difficulty,
and, so far as I saw, contoured the hills around the fiord more or
less continuously. The following aneroid-measurements were taken
by Mr. W. Andrews, F.G.S., on the hillside 1 mile north-west of
Vadso :— .

Feet
Trigonometrical Station..........sssseeseeeeeeeeeeeeeees 590
Highest raised beach ........:.sseeeeeeeeeeeeeeeeeesetess 285
240
Numerous raised beaches, the more prominent 232
OCCULTING aAb........-seeeereeecteceteteereseeeseeterees 227
140

A conspicuous shingle - bank north of Vadso
GOITER hee otic atennt aie ene aje es oneaee nies osecemecienmon 92
GB ealioveh. .- occas ah ca-tesczonss sewebeesenasecssecweeencceosss 0

The height of the Trigonometrical Station is given in the
Norwegian Government Map as 184 metres, whence it would appear
that the aneroid-readings should be increased by about 4 per cent.
This would give 296 feet as the level of the highest beach at
Vadsi, which is not far off Dr. Reusch’s measurement of 93
metres. It is worth noting that when the land stood at that level
the sea must have extended across the low ground separating

1 [The earliest observations that I am aware of were made by B. M. Keilhau
in 1837, Nyt Mag. for Naturvidensk. p. 244, and ‘Gea Norvegica,’ Christiania,
1850. ]

148 MR, A, STRAHAN ON THE RAISED BEACHES AND [May 1897,

the Varanger Fiord from the Tana Valley, and thus communicated
with the Tana Fiord so as to isolate a large tract of Norwegian
Lapland. From Karlbotn I could see the terraces extending far in
the direction of the Tana, but was unable to follow them for want
of time. It must be noted, however, that the level of the highest
beach between Nyborg and Karlbotn was only 235 feet, according
to an aneroid-measurement by Mr. Dickson—that is, 61 feet lower
than at Vadso.!

‘Che form of a raised beach is best seen at the highest level.
It is usually that of a level terrace of shingle resting against the
rock-slope, but not unfrequently, where the slope is gentle, the
shingle has’ been piled up in a ridge, so as to dam back the land-
water in a series of bogs and lakes, as already mentioned. The
terrace or ridge often runs for a mile or two continuously, but
sooner or later ends off against a rocky shoulder of the hill; in
more than one such case, and notably 14 mile east of Vadsd, the
beach starting as a mere line of pebbles on the western side of
such an obstruction increased in size eastward until it piled itself
as a conspicuous bank against the next shoulder, thus pointing to
the prevalent wind and wave-action having been from the west.

While traversing one of these rocky tracts on the hillside, it was
easy to follow the level of the beach, even in the absence of the
shingly terrace, for the rocks below that level were conspicuously
distinguished by their rounded outlines and by abundant pot-holes,
while those above it present the usual angular and splintered
appearance due to weathering. By following the level thus marked
out, I was led to more than one little isolated patch of shingle-
beach, occupying what had obviously been a small shingly bay in
the old shore-line. Good examples both of wave-worn rocks and
of these detached patches of shingle occur on a hillside north-east
of Vadso.”

Another noticeable point was the abundance of large erratics
lying on the old beaches. Though not absent above the highest
beach, they occurred in greater abundance on and below that level.
Among these were some of a conglomerate containing fragments |
of dolomite, which I believe had been derived from the Gaisa Beds,
though I did not find the rock in situ; boulders of igneous and
metamorphic rocks were common also, and had probably been brought
from the ground near the head of the fiord. I infer from the
presence of these erratics that floating ice was at work during the
formation of the beaches, though at the present day the Varanger
Fiord never freezes in its wider parts, and even in the tributary

1 [My opportunities were too limited to enable me to enter into the question
of differential uplift. ‘That the level of the highest beach varies is well known,
and some of the earliest observations on the subject were made by Bravais in
the Altenfiord— Sur les Lignes d’ancien Niveau de la Mer dans le Finmark ’
(extrait des ‘ Voyages en Scandinavie, en Laponie et au Spitzberg de la Corvette
La Recherche, Paris, 1848). Chambers made further notes on the variations
of level in 1850, ‘ Tracings of the North of Europe,’ pp. 199 et segq.]

_? The limit of waterworn rocks is equally well marked at Makur,
according to Dr. Reusch, ‘ Geology of Northern Norway,’ p. 91 & fig.

Vol. 53.]' | GLACIAL DEPOSITS OF THE VARANGER FIORD. . 149

fiords and shallower parts not to a sufficient extent for the trans-
port of large blocks.

The numerous ravines which are being cut by streams through
the raised beaches show nothing but sand and shingle roughly
stratified ; but the surface of the beach, and more especially the top
and landward side, is generally overspread by angular fragments.
This is partly due to the splitting of the pebbles by frost, but more
to the interruption of the process of shingle-making by the rising of
the land. A beach formed on a subsiding shore is rolled over and
over upon itself, and every part of it in turn is brought under the
action of the waves. On a rising coast, on the other hand, the
angular land-débris which forms the raw material, though it may
be piled up in a characteristic beach-ridge, escapes being turned
over and over, if the land by reason of its movement is gaining
upon the sea. Marine organisms have been recorded by Col. Feilden
and others in the beaches at about 50 feet above the sea in
this neighbourhood,’ but I could find neither shells nor bones at
the higher levels, all presumably having perished in so porous a
matrix.

We attempted more than once to count the beaches, but always
unsuccessfully. The difficulty arose from the multitude of small
subsidiary terraces like tide-marks. Here and there, and notably
north of Karlbotn, we walked over what had obviously been a
gravelly spit jutting out into the fiord. On the shelving surface of
such spits these small terraces occurred in great numbers, spacing
themselves out in a series of nearly concentric arcs on the shoal, but
merging one into the other on either side of it. If it could be proved
that each terrace marks the lapse of one year. the rate of elevation
of the land could be determined at once. The calculation would
probably show a rate of 1 or 2 inches a year, but I had no means:
of determining the exact gradient. On the other hand, these sub-
ordinate terraces may be merely storm-beaches, as suggested by
Dr. Reusch, though it must be noted that they are remarkably equal
and regularly spaced to have originated in such a manner,

The deposits of sand and shingle referred to above occur where
the fiord is broad and open, but a different type sets in towards
the head. Within a mile of Nyborg the Varanger Fiord terminates
in a low marshy tract. No large river enters it, and there is little
current beyond what is due to the slight rise and fall of the tide.
The deposit now forming between tide-marks is a blue mud, over
which are scattered many loose stones, none of large size. On
searching for the raised beaches, I found a similar blue mud, also
containing stones, and irregularly mixed with sand and shingle.
Near Karlbotn also, where the fiord is of the same character, part
of the raised beach-material consisted of blue clay, which, however,
gave place to sand and shingle at the village. The appearance of
the clay with its included stones, many of which, moreover, showed

’ Quart. Journ. Geol. Soe. vol. lii. (1896) p. 724.

150 MR. A. STRAHAN ON THE RAISED BEACHES AND [May 1897,

glacial strie, led me at first sight to believe it to bea till, an opinion
which I had occasion to change.

At Bodo there occurs a somewhat similar deposit. It forms a
terrace about 70 to 80 feet high, on which the town is built, and
consists of a bluish sandy clay, with many included stones and
shells of Leda (Yoldia) arctica in the position of life; it rests on a
rock-surface which is conspicuously moutonnée, but from which the
strie have been obliterated. Upon it, at a height of 70 to 80 feet
above the sea, ors lies a shell-marl containing, a others,

he following shells}

Mya truncata, very abundant, Littorina obtusata.
with the valves united. Hydrobia ulve (?).
Purpura lapillus. Lacuna crassior,
Trochus. Broken nullipore and rolled
Luttorina littorea. echinoderm-spines.

At Tromso6 I noticed a similar blue clay, and resting upon it, at a
height of about 10 feet above the sea, a shell-marl from | to 3 feet
thick, in which the following occurred :—

Pecten islandicus. Astarte compressa,

Mytilus edulis. Tellina calearea.

Mya truncata. Littorina littorea,

Saxricava rugosa. Tectura.

Cardium edule. Balanus porcatus.

Astarte borealis. And much nullipore.
sulcata.

On the mainland opposite Tromso the clay is worked for brick-
making, and is described by Colonel Feilden as ‘a homogeneous
mass of blue clay with boulders and stones interspersed throughout.
There is not a trace of bedding throughout the mass . . . the clay
contains ice-scratched stones, and mollusca are abundant throughout
the bed; examples of Cyprina islandica and Pecten rslandicus,
partially retaining their colour, are common, likewise stones to
which the bases of a Balanus are attached.’* In all these cases
mud is the material forming the bottom of the fiord.

My reasons for not applying the term ‘till’ to this deposit
are briefly as follows :—Till, or the almost synonymous term
Boulder Clay, which is used for this clay by Col. Feilden, always
contains grit and sand, and generally in larger proportions than
appear at first sight. When the proportion of clay is high, it is
always because argillaceous formations have formed the source of
supply, but even then it is a heterogeneous mixture of materials
of all degrees of coarseness, bearing internal evidence of having been
churned up, but not sorted under water. The fiord-clay, on the
other hand, is a homogeneous clay or fine silty sand, such as could
hardly have been accumulated except by the sorting action of
water. It contains delicate moilusca, nearly all in a perfect con-
dition, with the valves united; while, lastly, itis not such a material

1 These and the other shells were identified for me by Mr. Clement Reid.
The deposit was noticed so long ago as 1850 by ee ‘Tracings of the

North of Europe,’ p. 134.
2 Quart. Journ. Geol. Soc. vol. lii. (1896) p. 723.

Vol. 53. ] GLACIAL DEPOSITS OF THE VARANGER FIORD, 151

as would result from the grinding down of any rocks near which it
lies. In the apparent absence of stratification it resembles such a
deposit as the Scrobicularia-Clay of parts of the English coast,
which frequently breaks more readily along vertical shrinkage-
cracks than in any other directions, in consequence of its perfect
homogeneity. The strongest argument in favour of the glacial
origin of the blue clay lies in its containing scratched stones; but
the explanation of their presence is suggested by the fact that
stones are being strewn over the surface of the similar mud now
forming in the bottoms of the fiords, brought there, I presume, by
the ice which forms annually in the shallower waters. In con-
nexion with this it is worth noting that such a process of distri-
bution takes place occasionally even in this country ; the mud-flats
of the estuary of the Cheshire Dee have been known after hard
frosts to be dotted over for some miles with erratics of slag from
the Flintshire iron-works. Avoiding, on these accounts, the use
of the terms Till and Boulder Clay, I adopted the name ‘fiord-
mud,’ but the expression ‘glacio-marine’ used by Col. Feilden is
perhaps equally suitable, so long as it does not lead to the con-
founding of the deposit with formations of true glacial age. In the
three localities I have referred to, namely the Varanger Fiord,
Bods, and Tromso, I consider the deposit to belong to the raised
beaches, and to differ in no marked degree from the material now
accumulating in the neighbouring fiords. :

GLACIAL DeEposits,

To distinguish the beds of glacial age from the raised beaches
was seldom easy, for not only does the fiord-mud simulate Boulder
Clay, but the sand and shingle of the beaches might well pass for
esker-gravel. At first I was disposed to so class these gravels,
believing that their terraced outline alone was attributable to
rearrangement by waves." But after seeing some examples of
Glacial Drift, above the level of the highest beach, I came to the
conclusion that, though the material of the beach had often been
derived from Glacial Gravels, yet it had been completely redis-
tributed, and could no longer be regarded as part of the earlier
series.

Glacial Drift was by no means so typically developed as in this
country. J saw two examples, however, near Vadsé, which seemed
to be characteristic. In the one case mounds and ridges, enclosing
water-logged hollows, extended from the level of the highest beach
along the little valley of the Thomaselvy. This hummocky strip was
terminated abruptly by the smooth and level terrace of the beach,
and had evidently yielded much of the material of which it was
composed. Many of the mounds were overspread by, and perhaps

1 This is the explanation of a moraine with a perfectly level top which
dams up a lake at Hammerfest. Dr. Reusch supposes the surface of the
moraine to have been levelled by the waves, ‘Geology of Northern Norway,’

p- 101 & fig. The dam, consequently, has the composition of a moraine, but
the form of a beach,

152 MR. A, STRAHAN ON THE RAISED BEACHES AND [May 1897,

consisted of, angular sandstone-blocks, and they had assumed the
form of moraines, but the valley was too small to have contained more
than a diminutive glacier. A considerable quantity of talus encum-
bered the sides of the valley, and a winding stream had cut deeply.
into the hummocky débris, giving an impression of some antiquity
for the mounds. ‘The scene reminded me of many of our north
country gills.

The second example referred to consisted of a conspicuous mound
of sand and pebble-gravel, perched on the hillside north of Vadso,,
afew feet above the level of the highest beach. The mound is
slightly elongated in an east-and-west direction, and resembles a very
large oval tumulus, but its size and composition disprove its artificial
origin, for it contains none of the angular débris which lies round
its base, but consists wholly of sand and shingle, which would have
had to be carried from nearly a mile away. Though unusually
isolated and conspicuous, the mound presents the same general.
features as those that I have seen elsewhere, and as those of many
eskers in this country, which also often resemble closely great
tumuli.’

With these exceptions, nearly the whole of the ground that I
walked over was free from deposits of glacial age.

GLACIAL STRIz,

The shores of the Varanger Fiord are, of course, conspicuously
glaciated, though less so on the Gaisa Beds of the northern side than
on the crystalline rocks of the opposite coast. A finely-striated
surface, however, occurs at one of the landing-stages on Vadso:
Island, while the spit of land between the Nyborg and Karlbotn
branches of the fiord is well glaciated all over. The strie there
range between W. 10° N. and W. 25° N., and from an inspection
of a large number of ‘roches moutonnées,’ we were able to satisfy
ourselves that the ice moved from west to east—that is, down the
fiord. The distribution of the boulders supports this conclusion
in so far as the spit of land approximately divides Gaisa from
granitic erratics, showing that they have travelled along and not
across the fiord.

The strize appeared to be earlier than the raised beaches, for they
are often obliterated under them, though the glaciated form of the
rock is preserved, as in the case at Bodo referred to above. The
wave-worn rocks under the highest beach at Vadso form a stronger
argument, for there the surface remains as it was left at the
period of the beach, but shows no glaciation.” On the other hand,
the apparent freshness of some striated surfaces under raised
beaches led Col. Feilden to conclude that the glaciation went on
simultaneously with the emergence of the land,’ and undoubtedly

1 T should mention that Mr. Upton, who accompanied me, was disposed to
believe the mound to be a tumulus.

2 [The observations of Chambers and many other geologists who followed
him led to the same conclusion on the western coast also. ‘There, too, large
erratics lie on the top of the fiord-deposits. |

3 Quart. Journ. Geol. Soc, vol. lii. (1896) p. 736.

Vol. 53.| GLACIAL DEPOSITS OF THE VARANGER FIORD. 153,

the striz on the shore of Vadsd Island look remarkably fresh.
Their powers of survival, however, are vouched for by the fact that
they are exposed to the wash of every tide and the traffic of men
and boats, but have suffered no injury. Occurring as they do,
moreover, at the present sea-level, they would be contemporaneous
with the lowest beach—namely, that of the present day. This, in
view of the fact that the upward movement of the land is still
proceeding, amounts to saying that the glaciation should now be
taking place. So far asthe Varanger Fiord is concerned, this is not
the case.

The glaciation of the fiord seemed, so far as my limited obser-
vation went, to be the work of floating ice rather than of an ice-
sheet, and it was with great interest that I read, on my return,
Col. Feilden’s graphic description of the behaviour of drifting pack-
icein such asituation. J drew this inference from the fact that the
glaciation, though so well marked along the fiord, was inconspicuous,
if it existed at all, on the moorlands a few hundred feet above it.
Without a far more extended experience I could not say that it was
absent, but the scarps of hard sandstone which I examined near
Vadso, at a height of 400 to 600 feet above the sea, showed no
signs of having been crossed by ice, while the same rock between
Karlbotn and Nyborg, up to a height of about 400 feet, was smoothed
and scored all over. These observations indicate that the glacia-
tion was due either to a Varanger glacier or to ice drifting down
the fiord when the jand stood at a lower level. I have already
mentioned that when the land stood at the level indicated by the
highest raised beach there was a communication between the
Varanger Fiord and the Tana Valley, and so with the Tana Fiord.
The tide must then have had a free run round a large tract of
Norse Lapland, and penetrated many valleys which are now high
and dry. On the supposition that the striation was effected by
floating ice, the fact that the striation of the rocks near Karlbotn
extends nearly 140 feet above the level of the highest beach, indi-
cates that the land stood at a still lower level during the Glacial
Period than subsequently when the beaches were formed. However
this may have been, there can be no doubt that, even when the
land was 235 feet lower than at present, the conditions prevailing
in the Varanger Fiord would not only have allowed of the formation
of a considerable quantity of ice, but would have admitted of a
current to move it.

Discussion (ON THE TWO PRECEDING PAPERS).

The Prestpenr remarked that the first paper was of unusual
interest to him, for so long ago as 1876 he had argued that it
seemed impossible to conceive that the thick breccias and the large
boulders so abundant at the base of the Cambrian conglomerates in
Wales could have accumulated, unless the pre-Cambrian land had
suffered greatly from subaerial influences, including those of ice and
snow. When he visited the North-western Highlands in 1878
he felt equally convinced that the breccias at the base of the

O:3.6.8. No. 210. M

154 MR. A. STRAHAN ON THE RAISED BEACHES AND [May 1897,

Torridon Sandstone were the result of similar causes, and in
his paper in the ‘ Geological Magazine’ for 1880, ‘ On Pre-Cambrian
Volcanoes and Glaciers, he gave the facts then known. He
congratulated the Author on the admirable manner in which he
had worked out the evidence now produced from the Varanger
Fiord, and on his being able to show so conclusively that the
views put forward by Dr. Reusch were substantially correct.

Sir AncHIBALD GeErKrE congratulated the Author on having been
more successful in his Arctic expedition than his companions
the astronomers. Of the various possible interpretations of the
phenomena described, that adopted in the paper seemed to him
the most probable. At the same time it was not without its
difficulties. One of the most obvious of these was presented by the
striated pavement of quartzite below the boulder-bed. According
to the Author’s observations there appeared to be no break in the
stratification, the dark boulder-bearing deposit being merely a
local interruption of one continuous sequence of sedimentation.
But it was clear that the striated quartzite must have been in-
durated, possibly even as hard as it is now, before it could receive
and retain the strie. How could this induration take place under
water in a continuous series of deposits of loose siliceous sand ?

The objection seemed serious, but it might not prove to be
insuperable. It was conceivable that, in spite of the apparent
conformability in the sections examined by the Author, there might
really be a break of some magnitude represented by the boulder-bed,
though in that case there would be the objection that it seems unlikely,
after this prolonged interval, that sediment of precisely the same
character should be laid down with perfect conformability on the
previously striated bed of quartzite. If, however, no such chrono-
logical or stratigraphical break could be detected, there remained the
possibility that the striated quartzite acquired its induration under
water and while the immediately overlying sediments were being
deposited.

A number of instances were now known where silica seems to
have been deposited, on the whole, contemporaneously with the
sediment. The Gannister seams of the Carboniferous system might
be quoted, but still more remarkable was the evidence that the
radiolarian cherts of the Arenig Series in the South of Scotland had
become solid stone on the sea-bottom, and had been broken up
by volcanic explosions into angular fragments which were found in
the immediately overlying tufts.

With regard to the age of the Gaisa Series, the speaker was
inclined to adopt the view of Dr. Reusch, who compared this series
with the sparagmite of Central and Southern Norway. He himself
had seen the sparagmite am setw, and had been much struck with
its general resemblance, both in scenery and in lithology, with the
Torridonian rocks of N.W. Scotland. It was, like those rocks,
older than the Cambrian system. An interesting parallel might be
drawn between the Sutherland sections and those of Norway. The
Lewisian Gneiss was found to pass in rounded domes and hummocks
beneath the Torridon Sandstone. These forms so exactly resembled

A Te GLACIAL DEPOSITS OF THE VARANGER FIORD. 155

those of ice-worn surfaces that, although no striation of the gneiss
had been observed, they at once suggested the infiuence of glaciation.
Again, the composition, disorder, and lenticular character of the
coarse conglomerates sometimes met with at the base of the
Torridonian Series might perhaps find their counterparts in the
Gaisa rocks.

Dr. J. W. Greeory thought that the Society was to be con-
gratulated on this paper, and on the opportunity of seeing the
Author’s admirable photographs of the rocks. The previous failure
to discover traces of glacial action in high northern latitudes in
pre-Pleistocene times gave wide interest to Reusch’s paper; and
the corroboration of his views was of great value. The speaker
thought the deposits of special interest, as similar conglomerates
occupying identically the same stratigraphical position occur all
round the Polar basin, and in places where their age can be proved.
In Spitzbergen the occurrence of the conglomerates was discovered
last summer, and they are there pre-Devonian. Mr. Garwood,
during his ascent of Hornsund Tind, found fossils in the same
series. In North-eastern Greenland the conglomerates, associated
with the same red rocks, quartzites, etc., are known to occur, from
the work of Payer and Ryder; and the beds re-appear from beneath
the ice-cap on the western coast of Greenland. Farther south they
occur in Labrador, as part of a series of red rocks and quartzites
resting on the metamorphic rocks, and are referred to the Cambrian ;
the conglomerates consist of boulders, some of which are rounded,
and others are angular, while A. P. Low states that they range in
weight from an ounce toaton. Farther north-west the beds occur
in the North-eastern Provinces, and in the Coppermine River, and
finally they re-appear on the northern coast of Siberia. The con-
glomerates are therefore probably part of a circumpolar belt.
Paleontological evidence for their correlation is wanting, but they
always occur resting on the metamorphic series, and are older than
the oldest fossiliferous rocks of the area wherein they occur; indeed,
it can be often proved that they are pre-Silurian. The absence of
Silurian or Devonian pebbles in the Varanger Fiord conglomerates is
a strong argument for their early Paleozoic age, as Silurian rocks
probably once occurred a little farther north.

Mr. Grorez Barrow wished to know exactly what the Author
meant by the sentence ‘ the Boulder Clay has a somewhat schistose
structure.’

Mr. Hupixston, having visited the Varanger Fiord some forty-
two years ago, could to a certain extent corroborate the Author’s
statements as to the nature of the country and of the arenaceous
quartzite system prevailing in Kastern Finmark. Beyond the
region shown in his map, on the eastern side of the Tana Fiord, the
Stanganes Fjeld rises rather steeply to heights probably reaching
3000 feet. This is a quartzite wilderness, almost as white as snow,
having a strong external resemblance to the quartzite-mountains of
the North-western Highlands ; the system might thus include both
Torridonian and besal Cambrian beds.

The importance of the Author’s verification of Reusch’s statements

um 2

156 RAISED BEACHES OF THE VARANGER FIORD. [May 1897,

was very great. The late Dr. Croll had been desirous of obtain-
ing evidences of glaciation in the several formations anterior to
the great Ice Age. His failure to do so he attributed to the
circumstance that the evidences of glaciation are to be found
principally on land-surfaces, and that the transformation of a land-
surface into a sea-bottom would in most cases obliterate all traces
of glaciation. A striated bed-rock went much farther in this
direction than mere boulders and striated stones; and, as far as he
(the speaker) knew, these occurrences on the Varanger Fiord were
the only occurrences as yet established in the Northern Hemisphere,
with some possible exceptions in the case of the Talchirs. For a
grander exhibition of striated bed-rock they must look to the
Southern Hemisphere: Prof. Edgeworth David had recently brought.
before the Society such evidence from Southern Australia, referred.
to the Permo-Carboniferous period. |

With regard to the Author’s second paper, he could testify from
personal experience to the striking development of the terrace-
formations, tier above tier, on the northern side of the Varanger
Fiord.

Mr. H. B. Woopwarp remarked that there was plenty of schistosity
in the Boulder Clay of Cromer, as described by Mr. Clement Reid.

The Rey. H. N. Hurcuinson ventured to suggest that the difficulty
raised by a previous speaker with regard to the absence of a break
between the quartz-grits had not received the attention that it.
deserved. How could the lower grit have become sufficiently
hardened to receive these supposed glacial strixw, if the series was:
unbroken by any unconformity ? This was the difficulty, and it had
not been met. He did not feel at all convinced himself, and would
like to ask how many sets of strie the Author had observed.

The AvrHor, in reply, remarked on the interest of Dr. Hicks’s.
speculation as to the glacial origin of certain British rocks of appa-
rently the same age. To Sir Archibald Geikie’s question regarding the
relationship of the quartzites above the Boulder Clay to those below
it, he was unable to give a definite answer, further than to say that he
had seen no evidence of a break at that horizon. The characters of
the rocks and their dip suggested a continuous series, but the point
could not be settled in so brief a visit. The fact that the quartzite:
had been hard enough to receive and retain the striz undoubtedly
required explanation. It may, perhaps, have been buried, hardened,.
and subsequently laid bare by the ice, which presumably would
erode all unconsolidated material until it reached the first hardened
bed. In reply to Dr. Gregory, he had not stated that the glacial.
episode was local, but that the question of its extent must be left
for further investigation. The boundary-line between the Gaisa
and the crystalline rocks was not a thrust-plane, as suggested by
Mr. Barrow, but, at the point he had examined, a clear unconform-
able superposition. To Mr. Hutchinson he replied that three sets
wt striz occurred, one of which, however, was much stronger than.
the others. He was glad to see a tendency to accept the glacial
origin of the phenomena. Though it was difficult to do full justice
to it, the evidence on the ground was strong.

Vol. 53.] THE PEMBROKE EARTHQUAKES OF 1892 & 1893. 157

12. On the PemBroxe Harruauaxkss of Aveust, 1892, and NoveMBER,
1893. By Caarztes Davison, Sc.D., F.G.S., King Edward’s
High School, Birmingham. (Read January 6th, 1897.)

[Puate XI.]
ContTENTS.
Page
I. Earthquakes of August 17th—23rd, 1892 ................ 2.00 159
II. Harthquakes of November 2nd—3rd, 1893 .............0008- 168
Ty Onigingol the Hartquakesyis..622..-c6 so Ssetcddencectes Ses tieses 172

Tur Essex earthquake, one of the strongest ever recorded in this
country, occurred on April 22nd, 1884. Since that time the most
important shocks are those which were felt, principally in Pem-
brokeshire and the surrounding counties, on August 18th, 1892,
and November 2nd, 1893.! I propose in this paper to give a brief
account of the nature and probable origin of these earthquakes, as
well as of the slighter shocks which preceded and followed them.
Owing to the large number of observations (nearly 2000) which I
have collected, it is impossible for me to quote the authority for
every statement here made, or to present the evidence in any detail.
But, in offering my hearty thanks collectively to the numerous
ladies and gentlemen who by their kindness have made this investi-
gation possible, I should like to mention how greatly I am indebted
to Prof. Lapworth for frequent advice and assistance; to Mr. Marr
and Mr. Teall for information with regard to the geology of the
epicentral district; and to Mr. T. Mann Jones, F.G.8S., Mr. H. Cecil
Moore, Mr. Harold J. E. Peake, Mr. O. M. Prouse, F.G.S., Mr. G.
J.Symons, F.R.S., and especially to the Rev. W. M. Morris, formerly
of Cresswell Quay, near Pembroke, for valued aid in collecting
additional records.” My obligations to the last-named gentleman will
be obvious when I state that he visited for this purpose nearly
all parts of Pembrokeshire, and by his skill in cross-examining
observers extracted details which could not have been obtained by
any set of printed questions, however carefully framed.*

1 (It should be mentioned that the above sentence was written before the
occurrence of the Hereford earthquake of Dec. 17th, 1896.—March Ist, 1897.]

2 My best thanks are also due to the editors of the ‘ Times,’ the ‘ Standard,’
the ‘South Wales Daily News’ (Cardiff), the ‘Western Morning News’
(Plymouth), and many other newspapers, for their courtesy in inserting letters
from me asking for observations of the earthquakes.

° The expenses incurred in investigating the earthquakes of 1893 were
defrayed by a grant which J had the honour of receiving from the Government
Research Fund.

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Vol. 53.] THE PEMBROKE EARTHQUAKES OF 1892 & 1893. 159

I.—Earruavakes or Aveust 17th—23rd, 1892.

The following is a list of the earthquakes of this series, the
principal shock being denoted by a capital letter :—

a. August 17th: about 11.30 p.m. g. August 18th: 2.50 A.M.

b. August 18th: 0.22 a.m. h. Be about 4 A.M.

C. RA 0.24 a.m. i. August 19th: 9.30 a.m.

ae if 0.37 A.M. k. August 22nd: about 11.55 a.m.
e. 3 about 1.5 A.M. 1. August 23rd: 4.30 am.

t * about 1.40 A.M.

It should be remarked that the earthquake denoted by the letter
7.depends on the evidence of one witness only. But, as it is recorded
by a most careful observer, the usual rule of regarding such an
earthquake as doubtful should, I think, be suspended in this case.

(i) Preparatory Earthquakes.
a. August 17th: about 11.30 p.m.

Intensity, 3.—Number of records, 3; from 3 different places.

The shock was felt at Haverfordwest and Rudbaxton, 3 miles
farther north. At the same time, two rumbling noises were heard
at Pembroke.

b. August 18th: 0.22 a.m.

Number of records, 7; from 7 different places.

Two minutes before the principal shock, a distant sound, as of
thunder, was heard, without any accompanying tremor. The places
of observaticn are situated within a small area in the extreme south of
the county (see map, p. 158). The longer axis of the area is directed
approximately north and south, and its centre is either close to the
coast (about 13 mile west of Manorbier) or else beneath the sea.
The land-area over which the sound was heard contains about 33
square miles. Five minutes before the great shock, Dr. Propert, at
St. David’s, heard a noise as of a cart passing. It is uncertain
whether this observation refers to the same earth-sound as the
others,

(ii) Principal Earthquake. C: 0.24 a.m.

Intensity, 7.—Number of records, 712, from 555 different places ;
also 114 records from 111 different places at which, so far as known,
the earthquake was not observed.

Disturbed Area and Isoseismal Lines.—On the map illustrating this
earthquake (Pl. XI) are shown the isoseismal lines corresponding
to intensities 4 and 5 of the Rossi-Forel scale. Portions of those
corresponding to intensities 6 and 7 are also given, but the land-
areas traversed by these lines are not great enough to allow of the
remaining parts being drawn. On this account it is not possible to
determine the position of the epicentre with great exactness.

160 DR. C, DAVISON ON THE PEMBROKE EARTHQUAKES [May 1897,

So far as the land-areas are concerned the isoseismal 4 is
probably nearly accurate. The path of this line across the sea is of
course conjectural, but its trend just before leaving the land appears
to indicate that it is correctly drawn. Assuming this to be the
case, the area included within this curve is 255 miles
in length from north to south, 225 miles from east to
west, and contains about 44,860 square miles. This does
not, however, represent the whole of the disturbed area, for the
shock was plainly felt at several places beyond the limits of this -
isoseismal. There can be no doubt that it was felt at Tresco Abbey
in the Scilly Isles, at Dorchester, and at South Littleton near
Evesham, the distances of these places from the isoseismal being
14, 12, and 8 miles respectively. From the account given me
by Mr. J. J. Cole, F.R.A.S., I believe that an exceedingly slight
tremor observed by him at Sutton, in Surrey, must be attributed to
this earthquake. The distance of Sutton from the epicentre is
about 200 miles, and from the nearest point of the isoseismal 4
about 85 miles. Accounts have also been received from Ballina-
hinch and Milltown Malbay, in Co. Clare; but, from the great
recorded intensity of these disturbances, whether they be seismic or
not, I have no hesitation in rejecting the supposition of any con-
nexion between them and the Pembroke earthquake.

While it is impossible to assign definite limits to the disturbed
area, there can thus be no doubt that it must greatly have exceeded
45,000 square miles in extent. The disturbed area of the Essex
earthquake of 1884 is estimated by Messrs. Meldola and White at
about 50,000 square miles’; but this is the total area, not that
included within isoseismal 4, which must have been very much
smaller. ‘The Pembroke earthquake, though not nearly so strong
near the epicentre, must therefore have disturbed a far larger area.
It seems reasonable to attribute this to the wide distribution of
older and harder rocks over its disturbed area.

The isoseismal 5 bounds an area 172 miles long and 136 miles
broad, and containing about 18,660 square miles. The centre of
this curve is about 23 miles west of Linney Head. Its longer axis
is directed approximately north and south. If the earthquake were
due to fault-slipping, it follows that in the neighbourhood of the
epicentre the direction of the fault-line must be north
and south.

The next isoseismal (intensity 6) includes the whole of Pembroke-
shire and parts of the counties of Caerdigan, Caermarthen, and
Glamorgan. Only the eastern portion of the curve can be drawn,
the western part lying at some distance from the coast. Towards the
south it probably passes to the north of Lundy Island, but it would
be unsafe to presume too much on the strength of a single observa-
tion at that place. The land-area enclosed by this isoseismal
contains about 1070 square miles.

1 ‘Report on the East Anglian Earthquake of April 22nd, 1884’ (1885),
p- 22.

Vol. 53. OF AUGUST 1892 AND NOVEMBER 1893. 161

The central isoseismal (intensity 7) is in the form of a semi-
ellipse whose shorter axis is 21 miles in length, and whose longer
axis is directed north and south. As only the northern half lies on
land, it is somewhat doubtful whether the centre of the area lies
beneath the land or the sea; but in either case it is probably not
far from the coast, at a point about 33 miles 8.S.E. of Pembroke.
The land-area included within this curve contains about 450 square
miles. ‘The form and position of this isoseismal corroborate the
inference previously drawn as to the direction of the originating
fault.

Owing to the incompleteness of the isoseismal 6, there is some
uncertainty as to the direction in which the supposed fault hades.
Comparing the isoseismals 7 and 5, however, it will be seen that on
the eastern side of the epicentre they are separated by a distance of
52 miles, while on the western side the distance between them is as
much as 62 miles. If the district on either side of the epicentre
were fairly similar and uniform in structure, this would indicate
that the fault hades to the west. The great extent of the
disturbed area, and the fact that so much of it to the west is covered
by sea, lessen the force of this inference so far as it depends on the
relative position of the isoseismals.

On the other hand, the distance between the isoseismals 4 and 5 is
much greater towards the north, north-east, and east, and at first
sight this appears to lead to a contrary conclusion to that above
stated. In the neighbourhood of the epicentre, the distance be-
tween two given isoseismals is greater on the side towards which
the fault hades than on the opposite side. But at great distances
from the origin the inclined position of the fault-plane has a less
unequal effect on the intensity at equal distances on opposite sides
of the fault, and the consequence is that two distant isoseismals are
less separated on the side towards which the fault hades than on
the other. It is clear, however, that the relative position of the
isoseismals is governed to a great extent by the structure of the
districts through which the earth-wave had to pass. The intensity
appears to have died out less slowly on continuous land-areas thau
when sea-areas intervened, and thus the isoseismal 5 might have
extended still farther west if there had been no sea to traverse.
Thus, judging from this earthquake alone, a westerly hade of the
fault is more probable than an easterly one.

As the intensity of the shock is greater on the side of the fault
towards which it hades,! it follows that the fault must intersect the
ground along a north-and-south line lying a short distance (perhaps
2 or 3 miles) east of the centre of the isoseismal’7. Referring to the
map (p. 158), it will be seen that such a line nearly coincides with
the longer axis of the curve bounding the area over which the earth-
sound (6) was heard 2 minutes before the principal shock.

Nature of the Shock.—Owing to the time of its occurrence, many
of the observers were roused by the first tremors or by the pre-

* Geol. Mag. 1896, pp. 78-79.

162 DR.C. DAVISON ON THE PEMBROKE HARTHQUAKES [May 1897;

liminary sound, and thus the earlier phenomena were lost to them.
But there remain a large number of careful accounts written by
those who were awake at the time, and from these I select the
following as generally descriptive of the shock in different parts of
the disturbed area :—

Haverfordwest.—The shock began violently, gradually weakened,
then became stronger than at first; it lasted about 14 seconds.

Cresselly.—F our sets of vibrations—weak, medium, strong, weak;
the second and third sets separated by a few seconds, during which
a tremulous motion was felt. Duration, about 20 seconds.

At several other places in Pembrokeshire (especially Cheriton,
Cosheston, Manorbier, Redberth, and St. Florence), the nature of
the shock closely resembled that felt at Cresselly.

From these and many other accounts it is clear that near the
epicentre the shock, though continuous, contained two maxima of
intensity, the second of which was stronger than the first. Farther
away, the tremulous motion felt between the two maxima was
imperceptible, and the shock then consisted of two detached series of
vibrations separated by an interval of a few seconds of rest. The
following may be mentioned as examples :—

Clynderwen (Caermarthenshire): sharp vibrations increasing in
intensity for about 5 or 6 seconds, ceasing for 2 or 3 seconds, and
renewed with greater violence for about 10 to 15 seconds.

Port Eynon (Glamorganshire): two series of vibrations, with an
interval of about 10 seconds between them.

Cleavehouses (near Bideford): two distinct shocks, the first a
tremor like that produced by a clap of thunder, the second more
pronounced.

Ballywalter (near Gorey, Co. Wexford): two series of vibrations,
the second more intense; an interval of about 2 seconds between
them,

The double series of vibrations was observed practically all over
the disturbed area, at Rhyl in the north, Tresco Abbey (in the Scilly
Isles to the south), at Worcester on the east, and at Tullow (Co.
Carlow) onthe west. Excluding some rather doubtful cases, it was
noticed by 42 observers, 30 of whom record the relative intensity
of the vibrations. The second is said to have been the stronger at
22, and the first at 2, of these places, while at the remaining 6 places
the two series are described as of approximately the same intensity.
The two places at which the first series was regarded as the stronger
are Martletwy, in Pembrokeshire, and Treorchy, in Glamorgan-
shire; but there can be, I think, little doubt that these observations
are incorrect. When we remember that most of the accounts were
written after the lapse of several days or weeks, it is obvious that
some allowance must be made for defects of memory. It is
probable that the difference in intensity was not very great, but that
all over the disturbed area tbe second maximum was
stronger than the first. The significance of this conclusion
will be considered in a later section dealiug with the origin of the
shock.

Vol. 53.] OF AUGUST 1892 AND NOVEMBER 1893. 163

Sound-Area.—The earth-sound was heard at 334 places, at all but
5 of which the shock was also felt. So far as can be ascertained,
the sound-area coincided nearly, but not quite, with the area bounded
by the isoseismal 4; but the number of places near the boundary is
too small to allow of its being laid down with any approach to
accuracy. Towards the north, west, and south the two curves
are close together ; towards the east and south-east the sound-curve
extends a few miles beyond the isoseismal.

At 53 places it is expressly stated that no earth-sound was heard,
while the shock was distinctly felt. In some cases these places
are near the boundary of the sound-area and help to determine its
position ; but 26 of them are in the counties of Monmouth, Somer-
set, Gloucester, and Hereford. It is not at all an uncommon
experience to find the earth-sound unperceived by isolated observers
at places well within the isoseismal 5, This can hardly be due to
inattention on the part of the observers; rather, I believe, to the
sounds being below their lower limit of audibility.

Nature of the Earthquake-Sound.— Within the isoseismal 5 the
sound is generally compared to the passing of heavily-laden waggons
or traction-engines, to thunder, etc. The sound varied in pitch and
character. For instance, at Lamphey (near Pembroke), a murmur-
ing sound resembling that of sea-waves at a distance was heard
for 3 seconds, changing, when the shock was strongest, to a deep,
short, heavy boom like thunder, and continuing after the shock
for about 3 seconds with the same sound as at first.

Between the isoseismal lines 4 and 5, the slighter sounds which
gave rise to these variations were imperceptible ; the sound was
more monotonous, being compared most frequently to the low roll
of distant thunder, the moaning of the wind or of sea-waves, or to
rain falling on the leaves of trees.

Time-Relations of the Sound and Shock.—In the following Table
are given the time-relations of the beginning, epoch of maximum
intensity, and end of ‘the sound and shock. The figures show the
number of places in different districts at which the beginning, etc.,
of the sound preceded (p), coincided with (c), or followed (f), the
beginning, etc., of the shock :—

Epoch of
Beginning. Maximum End.
Intensity.

Pembrokeshire ............... 3 30 4 9} 41 Sal aes 8 | o4
Resi of Wales ............... LSh ee Ont 22) |e Geol 2 jos2ot 3
Devon and Cornwall ...... ro a a | Zileri Ot WE els, St fel Aaa t
Rest of England ............ Aes Olly kL Oo Ot” 2th 8
rGland. :ccee eee... 9 a a 2 3 1 2 2 6

164 DR. 0, DAVISON ON THE PEMBROKE EARTHQUAKES [May 1897,

In considering this Table some allowance must be made for
defective observation and errors of memory; but it is clear, as a
first result, that the beginning of the sound generally preceded that
of the shock, their epochs of maximum intensity coincided, and the
end of the sound followed that of the shock.

The most notable exception to this rule is the large number of
places in Pembrokeshire at which the beginning of the sound coincided
with that of the shock. One reason for this is that the preliminary
tremors were felt in that county, whereas in other districts the
beginning of the sound was necessarily referred to the beginning
of the principal vibrations. or vibrations which are rapid enough
to be perceived as sound, the ear, with most observers, is a far more
delicate seismoscope than the body. Moreover, there can be little
doubt that the seismic focus was many miles in length, and, though
partly under the sea, extended some distance up the county, so that
the margins of the focus (from which, I believe, the sound-vibrations
chiefly come) and the rest of the focus were almost equidistant from
many of the places of observation. In other parts of the disturbed
area, but especially in those which lie north and south of the
epicentre, the beginning of the sound preceded that of the shock,
because the nearest part of the focus was either the northern or
southern lateral margin.

At Penzance and St. Goran, in the south of Cornwall, the sound
is said to have preceded the shock entirely; and at Lydney, in the
west of Gloucestershire, to have ceased before the principal vibra-
tions were felt. These observations seem at first sight to prove
that the velocity of the sound was greater than that of the larger
vibrations, but such a conclusion is not sustained by the rest of the
evidence. At four other places in the south of Cornwall the epochs
of maximum intensity of the sound and shock are said to have
coincided, or the end of the sound to have followed that of the shock.
It is possible that in this district the epoch of maximum intensity
of the sound may really have preceded that of the shock by a short
interval, for these epochs are difficult to define with precision.
This is what we should expect, for the south of Cornwall lies
almost in the continuation of the supposed fault-line, and the
loudest sound-vibrations heard there would come from the southern
margin of the focus. From the neighbourhood of Lydney there
is no other evidence; but if the sound outraced the shock in one
direction at right angles to the focus, it would do so also in the other,
and the observations from the south-east of Ireland are entirely
opposed to this. On the other hand, the records both from
Gloucestershire and Ireland are what we should anticipate with a
westerly hade of the originating fault.

Another explanation of the observations is not impossible. At
Bally walter Gn Co. Wexford) and Newcastle (in Co. Wicklow) two
series of vibrations were felt, and the sound was perceived only in
the interval between them. Now, if the first and slighter series had
escaped notice, as it seems to have done in some places, the sound
would to the observers there have appeared to precede the shock

Vol. 53.| OF avGUST 1892 AND NOVEMBER 1893. 165

entirely. Though preferring the former, I am unable to decide
between these two explanations; but, at any rate, there seems to
be no reason for supposing that the sound-vibrations and the larger
vibrations travelled with different velocities.

Sea-Waves and Miscellaneous Phenomena.—The shock was felt
by several persons in boats, the sensation being the usual one of
having struck upon a rock. At Bulwell, on the southern shore of
Milford Haven, two or three waves were seen to dash up the shore,
the sea both before and after being absolutely still. The shock was
also felt by the engineer of a steamboat on the river opposite
Langwm. ‘The water, although perfectly calm before, became
suddenly swelled as with a heavy breeze. The boat seemed as if
passing over a swell, and then another, and then another—three
distinct waves, after which the water was troubled for a few
seconds; then it became perfectly calm as before.’ The waves
lasted from 15 to 20 seconds, and crossed the river from north-west:
to south-east.’

Some hours after the earthquake, one or more so-called tidal
wayes were observed at various places along the shore of the English
Channel, and were generally regarded as an effect of the earth-
quake. The places from which I have obtained accounts of such
waves are (from west to east): Scilly Isles, Porthpean (near St.
Austell), Lostwithiel, River Yealm, River Dart, estuary of the Exe
at Exmouth and Topsham, Weymouth, Portsmouth, and Bosham (in
Sussex). It is unnecessary to enter into any detailed description of
the waves, since, whatever their origin may have been, it is difficult
for the following reasons to connect them with the Pembroke earth-
quake :—(1) All the places are situated along the English Channel.
(2) The accounts obviously refer to several different waves, but, so
far as one wave in particular can be traced, it advanced from east
to west. (3) Similar waves were observed on the two days pre-
ceding that of the earthquake.

The shock appears to have had some slight effect on underground
water. At Green Croft (near Narberth), a well, shortly before the
earthquake, contained some water, and when visited soon afterwards
was found to be empty. At Marloes, according to an account
written about eight weeks after the shock, the springs in the upper
part of the village had been dry ever since, while the lower ones
were overflowing.

Only two accurate determinations of the time of occurrence appear
to have been made—namely, Oh. 24m. at Haverfordwest, and Oh.
26m. at Exeter. Both of these may be relied on, but, being given
only to the nearest minute, they are of little value except to show
that the surface-velocity of the earth-wave cannot have been less than
2050 feet per second. No traces of the earthquake are to be discerned
on the magnetograms of Kew and Greenwich, or on the records of
the horizontal pendulums at Strassburg and Nicolaiew.

1 T am indebted to the Rev. W. M. Morris for this account,

166 DR. 0. DAVISON ON THE PEMBROKE EARTHQUAKES [May 1807,

(iii) After-Shocks.
d. August 18th: 0.37 a.m.

Intensity, about 4.—Number of records, 23; from 23 different
places.
: The disturbed area includes the whole of Pembrokeshire and
parts of Caerdiganshire, Caermarthenshire, and North Devon. Its
boundary is indicated on the map (PI. XI) by a dotted and broken
line (—.—.), and, though somewhat uncertain on account of the
small number of determining stations, it is clear that its centre
must lie under the sea, and several miles south of that of the
principal earthquake.

The shock consisted of one series of very slight vibrations, the
accompanying sound being a low rumble, like a distant thunder-

peal.
e. August 18th: about 1.5 a.m.

Intensity, 3.—Number of records, 3; from 2 different places.

A very slight shock, felt at Dale and Pembroke Dock, at the
latter accompanied by a subdued rumbling sound. ‘The epicentre
was probably not far distant from either of these places.

f. August 18th: about 1.40 a.m.

Intensity, about 5.—Number of records, 114; from 111 different
places.

Disturbed Area and Sound-Area.—This was the strongest of all
the after-shocks, and, owing to the fact that many observers
remained awake and on the watch, it was felt over a comparatively
wide area.

The isoseismal 4 (see map, p. 158) can be traced with some
accuracy. Hxcept that it extends a little farther westward, it coin-
cides nearly with the isoseismal 7 of the principal earthquake. The
shorter axis of the curve is 24 miles in length, the longer axis is
directed approximately north and south, and the land-area enclosed
by it contains about 510 square miles. The centre is probably
close to the coast almost due south of Pembroke, but whether it
lies beneath the land or the sea is uncertain.

Outside this isoseismal, the places at which the earthquake was
observed are far apart, and it is impossible to draw the boundary
of the disturbed area or any other isoseismal. The most distant
places at which the shock was felt are Knighton and Glasbury
(Radnorshire), Cantref and Aberclydach (Breconshire), Exmouth,
St. Austell, and Kyle and Wexford (Co. Wexford). All of these lie
outside the isoseismal 5 of the principal earthquake, and one of
them, Knighton, is 26 miles beyond it.

The sound was everywhere much less intense than that which
accompanied the principal shock. With two exceptions (Llany-
byther in Caermarthenshire, and Treneglos near Launceston), it
was not heard beyond the isoseismal 6 of that earthquake.

Vol. 53.] OF AUGUST 1892 AND NOVEMBER 1893. 167

Nature of the Shock and Sound.—Detailed accounts of this earth-
quake are rather rare, but they all agree in representing it as much
simpler in character than the principal earthquake. ‘The following
may be given as examples :—

Tenby: tremulous motion for a few seconds, ending in a sharp
shake ; a low rumbling sound, becoming gradually louder until the
shake occurred, and then suddenly ceasing.

Maenclochog: a thud accompanied by a little swaying motion of
the ground and tremulous motion.

At most of the places, however, the tremulous motion and low
rumbling sound were not observed; the shock is described simply
as a jolt or thud; the sound as a cannon boom, beginning and
ending abruptly, and coinciding with the shock.

The shock was felt on the river opposite Langwm, and was
accompanied by a wave, but not nearly so marked as those seen at
the time of the principal shock.

g. August 18th: 2.50 a.m.

Intensity 3.—Number of records, 69 ; from 67 different places.

The disturbed area includes the whole of Pembrokeshire, most
of Caermarthenshire, and parts of the counties of Caerdigan and
Glamorgan ; in all, a land-area of about 1680 square miles. The
boundary of the area, so far as it can be traced, is shown by a dotted
and broken line on the map of the principal earthquake (Pl. XI).
Its position can be regarded as only approximately correct, on account
of the small number of observations made at a distance from the epi-
centre. The centre of the area obviously lies under land, and some
miles farther north than that of the principal earthquake.

The shock is everywhere described as a slight, tremulous motion.

The accompanying sound was heard at only 17 places, and is
always described as a distant, faint sound, or compared to very
distant thunder. At 39 other places it is expressly stated that no
sound was heard.

The sound-area is elliptical in form, 16 miles long, 13 miles broad,
and containing about 175 square miles. The centre coincides
almost exactly with the town of Haverfordwest. It will be
observed that the axis of the sound-area is situated 33 miles
west of that of the isoseismal 7 of the principal earthquake, to which
it is nearly parallel, and 6 miles west of that of the preliminary
earth-sound b. (See map, p. 158.)

lie August 18th: about 4 A.M.

Intensity, 2 or 3.—Number of records, 10; from 10 different
laces.
Part of the boundary of the disturbed area is shown in the map,
p- 158. Only the eastern half of it can be drawn, but this is sufficient
to show that the longer axis of the curve runs approximately east
and west, coinciding roughly with the axis of Milford Haven. The
shorter axis is 9 miles in length.’ The shock is everywhere described

168 DR. C. DAVISON ON THE PEMBROKE EARTHQUAKES [May 1897,

as a very slight quiver. There are no records of any sound being
heard to accompany it, and in this respect it is almost unique in
the annals of recent British earthquakes. The chief interest of
this shock and of that of Aug. 22nd (£) lies in the fact that the longer
axes of their disturbed areas are at right angles to those of the
preceding earthquakes.

i. August 19: 9.30 acu.

I have received only one record of this earth-sound. At
St. David’s, Dr. W. P. Propert heard a noise like thunder, but
more crashing and grating, without any accompanying vibration.
As most of the previous shocks were felt by this observer, it
appears to me that, though a solitary record, much reliance may
be placed upon it.

k. August 22nd: about 11.55 am.

Intensity, 4.Number of records, 21; from 13 different places.

The boundary of the disturbed area is a narrow oval, 19 miles
long, 74 miles broad, and containing about 112 square miles. Its
longer axis runs east and west, and lies about 14 mile north of
that of the last earthquake (h) on Aug. 18. The centre of the curve
is at a point 13 mile west of Honeyborough. (See map, p. 158.)

The shock consisted of a slight tremor. It was strongest at
Pembroke Dock, where three slight shocks of equal intensity were
felt at intervals of about 3 or 4 seconds, The sound, a slight
rumbling like the firing of a distant gun, was observed at only
6 places.

l. August 23rd: 4.30 a.m.

A slight vibration, felt by several observers in one house at
Pembroke Dock.

JI.—Earruavares oF NovemBer 2nd—8rd, 1893.

Only four undoubted earthquakes belong to this series. The
principal earthquake is indicated by a capital letter.
A. Nov. 2nd: 5.45 p.m.
b. i 6.1 P.M.
Cc. io about 6.15 or 6.80 p.m.
dy Novcsrd = 3, ) jl (Asm:

At Kidwelly (Caermarthenshire), a rumbling noise was heard 25
seconds before the principal shock. Also, at Hafren Hall, in the
same county, noises like distant thunder were heard at intervals
during the afternoon, no tremulous motion being felt. It is
doubtful whether these were of seismic origin.

Vol. 53.] OF AUGUST 1892 AND NOVEMBER 1893. 169

(i) Principal Earthquake. A: 5.45 p.m.

Intensity, 7—Number of records, 633, from 494 different
places ; also 164 records from 161 places at which, so far as known,
the earthquake was not observed.

The records of this earthquake are less numerous than those of
the principal earthquake of the preceding year, but they are far
more evenly distributed over the disturbed area.

Disturbed Area and Isoseismal [ines.—On the map of the earth-
quake (Pl. XI), the isoseismals 6, 4, and 3 are shown, and that part
of the isoseismal 5 which lies on land. The number of places at
which the intensity was 7 are too few to allow of the corre-
sponding isoseismal being drawn.

Towards the west and south the isoseismal 3 may possibly extend
somewhat beyond the limits of the curve laid down, owing to
the difficulty or impossibility of obtaining observations in these
directions. Judging, however, from the recorded intensity at the
places farthest west and south, I do not think that the position
assigned to the curve can be greatly in error. The length of the
isoseismal as drawn is 313 miles, the breadth 269 miles, and the
area enclosed by it about 63,600 square miles, that is, nearly three-
quarters of the area of Great Britain. This curve may be con-
sidered as the boundary of the disturbed area, for I have received
only one record from the region outside, and this one is not free
from doubt.

The next isoseismal (intensity 4) depends on a very large number
of good observations. Its length is 233 miles, its breadth 196
miles, and the enclosed area about 35,900 square miles. Its longer
axis is directed approximately HE. 30°N. and W. 30°S. A short
distance north of this line there occurs a small isolated area in the
neighbourhood of Manchester, in 1 which the intensity was equal,
or nearly equal, to 4.

The isoseismal 5 is confined to Wales and the north-western corner
of Devon, and it is therefore impossible to complete the curve.
The land-area included within it contains about 4680 square
miles.

The last isoseismal (intensity 6) that can be drawn is roughly
elliptical in form. Its centre is 33 miles north of Whitland, and
its longer axis is directed E. 15° N. and W. 15°S. The area
enclosed by the curve is 41 miles long, 28 miles broad, and con-
tains about 940 square miles. (See map, p. 158.)

The evidence with regard to the position of the originating fault
is not very complete. From the direction of the longer axes of the
isoseismals 6 and 4, it would follow that the fault-line must
run about E.15°N. and W.15°S. At several places within this
isoseismal a few buildings were slightly damaged, chimney-pots or
parts of chimneys were thrown down, but this occurred very rarely.
_ With one exception, all the places lie towards the southern or south-
eastern part of the isoseismal, and this would appear to indicate that

Q.J.G.8. No, 210. N

170 DR. C, DAVISON ON THE PEMBROKE EARTHQUAKES [{ May 1897,

the fault hades towards the south. But the inference is
far from certain, and, the isoseismal lines being incomplete near the
epicentre, no additional evidence is furnished by their relative
position. If it be correct, however, the fault-line must be situated
a short distance to the north of the centre of isoseismal 6.

Nature of the Shock.—The os accounts are given to illus-
trate the nature of the shock :—

White Lays (Pembrokeshire): a rather severe swaying motion,
in two series of vibrations, the second the stronger ; durations of
the first series, interval, and second series about 3" 4, amd 5 seconds
respectively : slight trembling and rumbling sound between the
two series; the rumbling sound preceded the sensible movement
by about 3 seconds, and followed it by the same interval.

Ballyhealy (Co. Wexford): two series of vibrations, the first the
stronger; durations of the first series, interval, and second series
about 6, 1, and 4 seconds, respectively; slight tremulous motion
and rumbling sound before the first series, in the interval between,
and after the second series.

At some distance from the epicentre, the tremulous motion
between the series was of course imperceptible, and the shock con-
sisted of two detached series of vibrations, generally of unequal
strength. Ata very large number of places, one of the two series
passed unnoticed or unrecorded, but as observations of the double
series come from nearly all parts of the disturbed area, even from
places so near the boundary as Bournemouth, Ashley, and Derby,
the number of such records is 49. In 18 of these the first series
is described as the stronger, and in 14 others the second. Within
and near the isoseismal 6, the second series is invariably estimated
as the stronger; and at a considerable distance, generally, but not
always, the first. The observations from neighbouring places are
not, however, always concordant, and this prevents the statement
of any general law.

Near the epicentre the shock consisted of rapid vibrations, but
at some distance from it the period seems to have lengthened out,
and the shock is described as a ‘swaying motion.’ The fifteen
places from which such records come lie within an oval area ex-
tending from Whitchurch (Salop) on the north to Wells on the
south, and from Llangammarch (Brecon) on the west to Hereford
on the east.

Sound-Area.—Records of the earthquake-sounds come from 253
places, while at 95 others it is stated that no sound was heard. In
this case, the boundary of the sound-area (shown by a broken line on
the map, Pl. XI) can be drawn with considerable accuracy. Its
length is 231 miles, breadth 210 miles, and the contained area
about 37,700 square miles. Its form and size are thus approxi-
mately the same as those of the isoseismal 4; indeed, if the
isoseismal were shifted about 10 or 12 miles north-eastward, it
would coincide roughly with the boundary of the sound-area.

™7

Vol. 53.] OF AUGUST 1892 AND NOVEMBER 1893. 171

Time-Relations of the Sound and Shock.—The numbers of places
at which the beginning, etc., of the sound preceded, coincided with,
or followed the beginning, etc., of the shock are given in the
following Table :—

Epoch of
Beginning. Maximum End.
Intensity.

————

Pe nieta ore fee een oe

| 2S saemoig and Caermar- \ 49 7 9 4| 97 7 3 2| 41

Penahnret sf. 2a ena
ESE OLIN BIOS 52.22.22 sees acceeeee 10} 6 2 Five estate cena ae 5 8
ATA aiden ach azatipn schepiiac. Wife arity Obits bOy el Qik. Dae 3G
TELAT b G Rai aR Rel Mita. oe 4 1 OO 1 Oi OF}. 2 0
atalety. seu sons Es. 80 | 16 | 15 Ora ee er TE ap

These figures lead to the same conclusion as those for the earth-
quake of 1892—namely, that the beginning of the sound generally
preceded that of the shock, their epochs of maximum intensity
coincided, and the end of the sound followed that of the shock.

At three places the sound is said to have ceased before, or just
as, the shock began. These are Eglwyswrw and Tenby in
Pembrokeshire, and Moat Lane Junction in Montgomeryshire.
The observations at the first two places contradict others made
there and at a large number of places in the immediate neigh-
bourkood, and must therefore be rejected. At and near Moat Lane
Junction the records are less discordant, and it is possible that the
instant when the sound was loudest preceded that when the shock
was strongest. Still farther north-east, at Ellesmere in Shropshire,
the epochs of maximum intensity of sound and shock coincided,
while the end of the sound followed that of the shock. This was
also the case at Courtown, in Co. Wexford.

The most probable conclusion to be drawn from all the observa-
tions is that the epochs of maximum intensity coincided in the
neighbourhood of the epicentre and near the boundary of the sound-
area, while at intermediate stations near the ‘longer axis of the
area the epoch of maximum intensity of the sound preceded that of
the shock. The explanation would seem to be, not that the velo-
city of the sound was greater than that of the larger vibrations,
but that the north-eastern lateral margin of the focus was of con-
siderable length, so that, at moderate distances, the sound-vibrations
which appeared loudest came from a point much nearer than the
centre of the focus; while, at great distances, the relative inten-
sities of the sound-vibrations from the lateral margin and from the
upper margin of the focus were sensibly the same, so that the
principal vibrations were felt during the interval when the sound
was loudest.

N2

172 DR. C, DAVISON ON THE PEMBROKE EARTHQUAKES [May 1807,

(i) After-Shocks.

b. November 2nd: 6.1 p.m.

Intensity, 4.—Number of records, 64; from 57 different places.

This shock was felt over the greater part of Pembrokeshire and
Caermarthenshire and in the southern part of Caerdiganshire. The
disturbed area is 43 miles long, 29 miles broad, and contains about
1000 square miles. The longer axis is directed about E. 25° N..
and W. 25° §., and the centre of the area lies 24 miles north-west
of Narberth, that is, about 8 miles W. 20° 8. of the centre of the
isoseismal 6 of the principal earthquake. The line joining the
two centres is thus roughly parallel to the longer axes of both
curves. (See map, p. 158.)

The shock was felt at 45 places, at 15 of which the sound was
not heard. The sound was heard at 22 places, and at 10 of these

the shock was not felt. So far asthe observations extend, however,,.

the disturbed area and the sound-area approximately coincide. .

The shock is always described as a tremulous motion, as a rule
exceedingly slight. The rumbling sound was also very faint, and
it is not surprising that it should have escaped notice at many
places.

c. November 2nd: about 6.15 or 6.30 p.m.

This was an exceedingly slight shock. It was felt at Llandyssul
and Blaendyffryn in Caerdiganshire, possibly also at Llanstinan and
Pen-ty-parc in Pembrokeshire, though the last two places are at

some distance from the others. The epicentre obviously lies north--

east of that of the principal earthquake.

d. November 3rd: about 1 a.m.

The only records of this slight shock come from Llanilar and’

Rhydlewis in Caerdiganshire, and Newcastle Emlyn on the border of
that county and Caermarthenshire. They appear to indicate a still
further displacement of the epicentre towards the north-east. With
regard both to this and the preceding shock, it should be remarked

that, except their proximity in time of occurrence and disturbed.
area, there is no evidence for connecting them with the same fault--

system as the first two earthquakes.

IlI.—Oriein oF THE EARTHQUAKES.

In correlating the earthquakes described above with the faults:

of the epicentral district, difficulties arise from the great number of
known faults in one part and their scarcity in another. The

majority so far traced are longitudinal faults, and, in the south of

Pembrokeshire, run roughly in an east-and-west direction, trending
some degrees north of east in the west of Caermarthenshire. It can
hardly be doubted that a series of transverse faults crosses them

approximately at right angles, though few are [marked on the-

Vol. 53.] OF AUGUST 1892 AND NOVEMBER 1893. . 173

Geological Survey map. In the map of the epicentral area (p. 158),
the principal faults are indicated by broken lines. They are founded
on the Index-map of the Geological Survey (on the scale of 4 miles
to 1 inch), on the map which accompanies the paper of Messrs. Marr
and Roberts on ‘The Lower Paleozoic Rocks of the Neighbourhood
of Haverfordwest,’* and on information kindly given to me by
Mr. Marr. The two faults, whose positions are inferred from the
seismic phenomena, are shown by dotted lines aa, 63. So far as I
am aware, no geological evidence of their existence has been dis-
covered, but in this part of the district the exposures are, I believe,
insufficient to give much force to negative evidence.

Earthquakes of 1892.—Several of the earthquakes of 1892,
including the principal earthquake, are apparently connected with
a transverse fault aa, hading to the west. There is not sufficient
evidence to determine whether this was the case with the first
shock (a), but, assuming it to be so, there must have been a slight
slip a short distance north of Pembroke. This was succeeded in
less than an hour by another slip farther south, the centre of the
focus being close to the coast. The focus may have extended under
both land and sea, but the amount of slip must have been very
small, for no tremor was perceptible on the surface.

The function of these preliminary slips seems to have been to
relieve the stress at two isolated spots, and thus to equalize the
residual stress over a great length of the fault. The total relief
was, however, very slight, for, 2 minutes after the second slip,
the most important movement took place. Owing to the incom-
pleteness of the isoseismal 7, no estimate can be formed of the
length of the focus, but it was certainly many miles. Its centre
coincided approximately with that of the earth-sound (6), and the
focus itself lay partly under land and partly under sea. The
double nature of the shock, and the greater intensity of the
second series of vibrations in practically all parts of the disturbed
area, show that the slip was interrupted, the sliding mass almost
halting for a few seconds; but whether the second and more
important part of the slip occurred in the same, or a different, region
of the fault, there is no evidence to show. The latter alternative
seems, | think, the more probable, when we consider the dimensions
of the displaced rock-mass.

However great the amount of slip may have been near the centre
of the focus, it must have died out before reaching the surface, for
no trace of a fault-scarp is recorded within the epicentral tract.
The water-waves observed at Bulwell and near Langwm can hardly
have been of the nature of a ‘ great sca-wave,’ such as would be
produced by a sudden elevation or subsidence of the sea-bed, but
rather what Mallet would have called ‘forced sea-waves.’ They
were no doubt due to the wave of direct vibrations transmitted
through the water.

* Quart. Journ. Geol. Soc. vol. xli, (1885) pp. 476-491.

174 ‘DR. C. DAVISON ON THE PEMBROKE EARTHQUAKES [May 1897;

Tn less than a quarter of an hour, the first after-shock (d) took
place. As so little of the disturbed area lay on land, it is impossible
to determine the position of the focus,.except that the whole or the
greater part of it must have lain beneath the sea. If it were con-
nected with the transverse fault aa, the chief displacement of the
series was evidently followed by a slip farther to the south.

The next after-shock (¢) had so few observers that its connexion
with this fault is also uncertain. All that can be asserted is that
its focus lay north of that of the principal earthquake.

Then foliowed the strongest of the after-shocks (f). From the
approximate coincidence of its isoseismal 4 with the isoseismal 7 of
the chief earthquake, we may infer that it was caused by another
slip along the transverse fault aa, and in almost exactly the same
region.

By the slip which produced this earthquake, the pre-existing
stress along the fault aa was practically relieved. But the displace-
ments by which this relief was effected increased the stress along
adjoining faults, with the result that the fourth after-shock (gq)
points to a slip along another surmised transverse fault (3, approxi-
mately parallel to the fault aa and about 6 miles farther west.
The increase of stress having been inconsiderable, one small slip
was enough to restore equilibrium along this fracture.

In about 34 hours after the principal earthquake, there occurred
a slight shock (4), which is clearly connected with one of the longi-
tudinal systems of faults running east and west. Four days later,
on August 22nd, a somewhat stronger shock (/) took place, which
may be traced to another fault of the same system, lying a mile
or so farther north. On the map (p. 158), two faults are shown,
which, if continued, would occupy the required positions; for, as
Mr. Marr informs me, they are both thrust-planes hading at a high |
angle probably to the south.

Earthquakes of 1893.—The first two shocks of Nov. 2nd, 1893, are
evidently connected with one and the same fault, for the line join-.
ing the centres of the isoseismal 6 of the principal earthquake (A)
and. of the disturbed area of the first after-shock (6) is approximately
parallel to the longer axes of the same curves. The direction of the
originating fault must be about E. 15° N. and W. 15°S., but with
regard to its hade the evidence is doubtful. The fault ee (see map,.
p- 158) is a thrust-plane hading probably to the north; the fault (2
is also a thrust-plane, but probably hading in the opposite direction. |
As traced on the map it is possibly incomplete, for Messrs, Marr and.
Roberts’s map does not extend beyond the eastern end shown; but
its course so far is parallel to the fault-line implied by the seismic
evidence. Neither this fault nor the preceding will, however, satisfy
the required conditions, for they both dip away from the common
axis of the isoseismal lines; but the district between them, as
Mr. Marr informs me, ‘is simply wattled with minor faults,’ and it
is probably to movements along one of these that the earthquake
of 1893 must be assigned.

Vol. 53.] OF AUGUST 1892 AND NOVEMBER 1803. 175

There can be little doubt, I think, that the fault-slips of 1892
affected the conditions of stress along this neighbouring fault, so
that the displacements along it occurred earlier than they might
otherwise have done. There is no evidence of any preliminary
slips, the first that took place being the most important of the series.
As in the principal earthquake of 1892, the slip was discontinuous :
but whether the focus consisted of two detached portions, or
whether the slip was repeated at the same or a different part of
the fault, is doubtful, for the records of the relative intensity of
the two parts of the shock are discordant. The principal part of
the focus may have been as much as 10 or 12 miles long, but the
length of its eastern margin must have been considerable, and
much greater than that of the western margin. This is shown by
the position of the boundary of the sound-area with respect to
that of the isoseismal 4, and also by the time-relations of the sound
and shock.

The stress being more completely relieved on the eastern side of the
focus, we should expect the next slip to take place on the opposite
side. And this we find to have been the case, for in the first after-
shock (6), which occurred a quarter of an hour later, the epicentral
area was shifted to the W.S.W. Though much less in amount of
slip, the focus must have been of almost the same length as that of
the principal earthquake, and partly overlapping it, but with its
centre lying about 8 miles farther to the W.S.W.

Assuming, as is very probable, that the second and third after-
shocks are connected with the same fault, the next slip occurred on
the eastern side of the principal focus and at increasing distances from
it. The great rock-mass, once set in motion, thus appears to have
oscillated slowly, first to one side and then to the other, before finally
coming to rest.

Conclusion.—I have not yet been able to study in any detail the
seismic history of the district principally affected by these two series
of earthquakes. Several shocks have been felt in Pembrokeshire
and Caermarthenshire during the present century, some of which had
their origins elsewhere, and at least three (in 1802, 1832, and 1840)
possibly in the latter county. For more than 50 years, however,
there appear to have been no slips of any consequence along the
fault-system here considered, and the following facts are therefore
worthy of notice :—(1) that, after this prolonged interval of repose,
the earlier movements took place along transverse, and the later
along longitudinal, faults: (2) that the three faults of the latter
series lie successively the one to the north of the other, as if the
abrupt displacement of a rock-mass over one thrust-plane impelled
the further advance of those immediately below.

PLATE XI.

Map of the Pembroke Earthquakes of August 1892 and November 1893, on
the scale of 40 miles to 1 inch.

176 THE PEMBROKE EARTHQUAKES OF 1892 & 1893. [May 1897,

Discussion.

The PrestpEnt said that the Author’s enquiries into the relation-
ship between earthquakes and faults were of great interest. It is
well known that the older rocks in Pembrokeshire have been
much crushed and broken, and that thrust-faults of great mag-
nitude occur there. It is also a fact that the area has been
frequently affected by earthquake-shocks, one of which, many years
ago, caused serious damage to the Cathedral of St. David’s.

The Rey. J. F. Braxe remarked upon the apparent absence of any
signs of disturbance on the surface. If these earthquakes were due
to slips, it was strange that none of them should yield this evidence.
In the cases previously described by the Author the principal
evidence was the association with well-known faults, which might
be lines of fresh dislocation ; but in the present instance faults had
to be hypothecated. Though, therefore, the speaker believed the
theory to be the true one, the evidence for it appeared extremely
weak,

Mr. H. H. Starnam, Mr. W. Wuiraxer, and Mr. Marr also
spoke.

Quart. Journ. Geol. Soc. Vol. LILI. Pl. XT

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The dotted lines
the beundary of the sound area of the same earthquake.

Vol. 53.] STRUCIURE OF THE SKULL OF A PLIOSAUR. 177

13. On the Structure of the Sxutt of a Puiosaur. By C. W.
Anprews, Esq., B.Sc., F.G.S., Assistant in the Geological
Department, British Museum. (Read January 6th, 1897.)

[Puate XIT.]

In the present communication I propose to give a short account
of the cranial structure of the Plesiosaurian reptile known as
Pliosaurus ferox (Sauvage), a very fine skull of which has recently
been acquired by the British Museum. Like so many other
reptilian fossils from the Oxford Clay, this specimen was obtained in
the neighbourhood of Peterborough by A. N. Leeds, Esq., F.G.S., who
has expended much time, patience, and skill in fitting together the
numerous fragments into which the bones were found broken.
The result, however, is well worth the trouble taken, and the
specimen is now perhaps the finest Pliosaur skull known. The
extreme length from the occipital condyle to the anterior extremity
is 112 cm., while the width at the quadrate region, perhaps
somewhat exaggerated by crushing, is 50 cm.

The description of this skull is facilitated by the great similarity
which exists between it and that of Peloneustes philarchus, of which
an account has already appeared.” This similarity is so striking that
it seemed not impossible that the present specimen might be merely
the skull of an old individual of Peloneustes: but there are a
number of differences which tend to show that such is not the case.
In the first place, the total number of teeth in the upper jaw of
Peloneustes is greater, and there are six instead of five in the
premaxilla; it is, however, possible that a premaxillary tooth
might be lost in growth, since this actually occurs in Crocodilus
porosus,* so that this latter point is of less importance than might be
supposed. Again, in Peloneustes there is no diastema between the
premaxillary and maxillary alveoli, and the variation in the size of
the teeth in different parts of the jaw is less. ‘he form of the
palatines and transpalatines is also different. Unfortunately the
lower jaw and all the rest of the skeleton is missing in the present
instance, so that the length of the symphysis and other characters
pointed out by Lydekker are not available for the determination of
this specimen.

It may be remarked that, although the teeth of this form from the
Oxford Clay of Peterborough agree precisely with those described
by Sauvage from the same horizon at Boulogne, under the name
Inopleurodon ferow,* they differ considerably from those from the
Kimeridge Clay, upon which Owen founded the genus Pliosaurus,

1 See Brit. Mus. Cat. Foss. Rept. pt. ii. (1889) p. 145.

? Andrews, Ann. Mag. Nat. Hist. ser. 6, vol. xvi. (1895) p. 242.

3 Boulenger, ‘ Fauna and Flora of British India: Reptilia and Batrachia’
(1890) p. 5.

* Bull. Soc. géol. France, ser, 3, vol. i. (1873) p. 378.

178 _ MR. C. W. ANDREWS ON THE STRUCTURE [May 1897,

being circular in section instead of trihedral. ‘They, however, show
a distinct tendency towards this typical form in the absence, or at
least scanty development, of ridges on their outer surface ; and since
the skull and skeleton of the Oxfordian and Kimeridgian forms,
so far as known, are closely similar, I prefer, for the present at
least, to follow the British Museum Catalogue in referring both to
one genus—Pliosaurus.

DESCRIPTION OF THE SKULL.

Most unfortunately, this skull was not found associated with any
other portions of the skeleton, even the mandible being entirely
absent. As already mentioned, it is much crushed, nevertheless
all the more important points in the structure can be made out.
A number of the characteristic teeth, beautifully preserved, occurred
in close proximity to the skull, but only one or two broken bases
remain actually in the alveoli.

The basi-occipital (Pl. XII. fig. 1, occ.) is very similar to
that of Peloneustes, but the condyle is relatively rather larger, and
is also rounder and more prominent; it has a well-marked dimple-
like depression marking the former position of the notochord. The
arrangement of the very massive ventro-lateral processes is the same
as in the smaller form; in the present specimen the pterygoids,
which terminate posteriorly in a strong transverse ridge, have been
crushed up upon them. ‘The surfaces for union with the exoccipital
look upward and somewhat outward; they are separated by a
narrow interval only.

The exoccipitals (fig. 2, p. 181, ew.oc.), which form the sides
of the foramen magnum, are stout solid bones, the upper ends of
which have been broken away by the crushing down of the dorsal
surface of the skull. Laterally they, or, more correctly speaking, the
opisthotic elements fused with them, bear extremely long (15 em.)
paroccipital processes (fig. 2, p.oc.). The distal extremity of these
is somewhat expanded into a spathulate form, the outer surface of
the expanded portion being flattened and rugose. This surface
appears to have formed a close union with the inner surface of the
anteriorly-directed process of the quadrate, by which that bone
unites with the posterior pterygoid ramus; possibly, however, a
portion of the overlapping ‘squamosal’ may intervene to some
extent between the outer end of the paroccipital process and the:
quadrate.

The supra-occipital is too much crushed for description, and
the basisphenoid is completely concealed above by the depressed
roof of the skull and ventrally by the pterygoids.

In front of the basisphenoid, the ventral axis of the skull is
prolonged forwards by the bone which, for reasons given elsewhere,
I regard as the parasphenoid (fig. 1, p. 179, pas.). The hinder
portion of this is partly concealed by the pterygoids, and indeed the
exact line of division between the median expansion of these bones ,
_ and the parasphenoid is not in this case to be made out. Anteriorly

Nolir'2.] OF THE SKULL OF A PLIOSAUR. 179

the latter element runs forward in the form of an elongated spear-
head, of which the postero-lateral borders form the inner margin of the
posterior palatine vacuities, while the antero-lateral borders form a
sutural union with the pterygoids (see fig. 1). On the upper surface

Fig. 1.—Posterior portion of palate, showing the relations of the
parasphenord and transverse bones.

Baie
7u, = jugal. | pt. = pterygoid.
pal, =palatine. ~~ sq. = squaincsal.
pas, = parasphenoid. trs. = transverse bone.

[About } nat. size. |

of the posterior portion of the parasphenoid is a mass of osseous
tissue of somewhat irregular form. This is probably the remains of
the anterior portion of the true basis cranii derived from the trabe-
cule, and either forms an. anterior portion of the basisphenoid
or an imperfectly ossified presphenoid. The length of the exposed
portion of the parasphenoid is roughly 19 cm., its width between
the post-palatine vacuities 1:8 cm., and its greatest width between
the pterygoids 2:2 cm.

The pterygoids (pt.), in their general form and relations, are
closely similar to those of Peloneustes, but there are one or two
well-marked differences. The anterior rami, which are very stout
and massive, widen gradually from before backward, and unite
externally with the palatines in a straight suture (convex externally

180 MR. C. W. ANDREWS ON THE STRUCTURE [May 1897,

in Peloneustes) ; they do not appear to have met on the middle line,
at least anteriorly, as in the smaller form, so that for some distance
there was a narrow median vacuity. Behind this, however, they
unite with one another for about 4 cm., behind which again they
are separated by the parasphenoid. About opposite the anterior
border of their lateral ramus, that is relatively farther forward
than in Peloneustes, their median borders diverge from the para-
sphenoid, and enclose with it the posterior palatine vacuities
(Pl. XII, p.p.vac.), which are here about 10 or 11 cm. in length.
The posterior union of the pterygoids over the basisphenoid and
part of the basioccipital forms a suture about 9 cm. in length, the
posterior portion of which for about 6 cm. is raised into a thick and
prominent ridge. In front this forks into a pair of crests, which
curve outward through about a quarter of a circle, forming
externally the hinder border of the lateral ramus of the bone.
This crest terminates in a massive tuberosity, the flattened top
of which looks downward and outward; this, together with a
similar prominence on the transpalatine, forms the downwardly-
directed process corresponding to that seen on the palate in
Peloneustes, Sphenodon, and many other reptiles.

The outer border of the posterior ramus (fig. 2, p. 181, p.pé.)
is thick and rounded; posteriorly, it passes into the backwardly-
produced process, the distal portion of which underlies and unites
in close suture with the broad, forwardly-directed process from the
inner border of the quadrate, the two meeting in an oblique suture.

The lateral ramus of the pterygoid (fig. 2, l.pt.), the hinder border
of which is formed by the curved ridge, as above described, has a
thin external edge overlapping the inner edge of the transpalatine.
The anterior border is at right angles to the skull-axis, and unites
with the palatine.

The transpalatine (Pl. XII & fig. 1, p. 179, ws) iiewam
L-shaped bone, having a prominent tuberosity at the angle. This
tuberosity, as above mentioned, forms the anterior half of the
downwardly-directed process of the palate. One of the limbs of
the L is directed forward, the other outward and a little backward.
Of the former, the inner edge forms a sutural overlap upon the
pterygoid, while the outer forms the inner border of the suborbital
vacuity. The outer arm joins the maxilla and possibly, to some
extent, the jugal, but its exact relations to this latter are not clear ;
it forms the posterior boundary of the suborbital vacuity.

On the dorsal surface of the pterygoid, there is on the left side
of the present specimen the well-preserved lower half of the
epipterygoid or columella cranii (fig. 2, col.). Its basal portion
is an elongate oval, with its long axis antero-posterior, and its
anterior edge opposite the hinder margin of the lateral ramus of the
pterygoid ; this expanded basis forms a firm junction with the upper
surface of the pterygoid. In its middie portion the bone contracts
considerably in width, but its antero-posterior diameter is still
far greater than its width from side to side. On the right side of
the skull it can be seen that the upper end of the epipterygoid is

Vol. 53.] OF THE SKULL OF A PLIOSAUR. 181

again expanded and unites with the downwardly-directed lateral
region of the parietals; the actual suture is unfortunately not
visible.

Fig. 2.—Lateral view of cranium, showing the relations of the
columella and paroccipital process.

col. = columella. i.pt. = lateral ramus of pterygoid.
ex.0¢. = exoccipital. p.pt. = posterior ramus of pterygoid.
o¢.c. = occipital condyle. p.oc. = paroccipital process.

par. = parietal.
[About 4 nat. size. |

The palatines (Pl. XII, pal.) are elongated bones bordered
internally by the pterygoids and, probably for a short distance in
front, by the vomers ; externally by the maxille, and posteriorly
by the lateral wing of the pterygoids and the suborbital vacuities..
Anteriorly they probably formed part of the hinder border of the
internal nares, but their relations in this region are obscured by the
crushing that has taken place. Lach palatine is perforated by a
foramen, about 2 cm. in diameter, lying 4 cm. from the hinder
and 1 cm. from the inner margin of the bone; these foramina do
not occur in the palatines of Peloneustes.

The vomers (vo.), which for the anterior four-fifths of their
length are anchylosed with one another, are very large bones, about
40 cm. long. Anteriorly they run up some distance (13 ecm.)
between the premaxille, behind which they are bordered by the
maxille. They are overlapped to a considerable extent by both
these elements, and opposite the alveoli of the second maxillary
teeth they only appear in the middle of the palate as a narrow strip
about 6 mm. in width. As in Peloneustes, the united vomers form
the median bar, convex from side to side, between the internal
narial openings, opposite the middle of which they are together
about 3 cm. in width. Posteriorly they widen out to about
4-8 cm., and behind the nares they terminate in a fan-shaped
splintery suture against the pterygoids and palatines. It should be
noted, however, that the relations of the hinder end of these bones
are not quite clear, but there is no reason to suppose that their

182 MR, C. W, ANDREWS ON THE STRUCTURE [May 1897,

arrangement differs in any way from that described in the skull of
Peloneustes, in which this portion of the palate is well preserved,
and its structure perfectly clear.

The premaxille (Pl. XII, p.ma#.) are very large bones, each
consisting of a dentigerous body, which is produced backward
on the palate into a ‘short palatine process, and an enormously
elongated facial process which extends far behind the external nares
and terminates in a suture with the frontals.

The teeth borne by each premaxilla are five in number. The
first pair are comparatively small, directed forwards, and almost in
contact in the middle line. The second, third, and fourth increase
in size in the order named, while the fifth is considerably smaller
than the fourth. Between the last premaxillary tooth and the
first in the maxilla there is a diastema about 6 cm. long, which is
crossed near its middle point by the premaxillo-maxillary suture.
Immediately internal to the alveoli there is a deep groove, at the
bottom of which the tips of the successional teeth may be seen.
The inner wall of this groove is formed by a prominent ridge, which,
joining that of the opposite side, forms an elongated triangular
- raised area in the middle of the anterior end of the palate. By the
divergence of the ridges posteriorly a short groove is formed, which
is closed behind by the prominent anterior end of the vomers. The
upper surface of the body of the premaxille is rough and pitted
with numerous foramina. The immense facial processes together
form a broad convex ridge along the upper surface of the snout;
behind they form a complicated zigzag suture with the frontals.
The suture between the premaxille ‘is persistent.

The maxilla (Pl. XII, mz.) in its general form closely resembles
that of Peloneustes, but instead of bearing from twenty-eight to thirty
teeth as in that genus, there are only about twenty. Of these the
first two were small, the next two very large. Behind these there is a
gradual decrease in size as far asthe ninth. The tenth and eleventh
are again larger, and behind these the series decreases gradually,
the hindermost teeth being very small. The whole alveolar margin
of the jaw, seen from the side, is sinuous in outline: the first con-
vexity occurring in the premaxilla, the next opposite the second
and third maxillary teeth, the last and least marked opposite the
tenth and eleventh.

As already mentioned the anterior palatal portion of the maxilla
forms an extensive overlap upon the vomer. Opposite the internal
nares its inner border is raised into a high, thin ridge, which forms a
kind of outer wall to the opening. Behind the nares the maxilla
first joins the palatine, then forms the outer boundary of the sub-
orbital vacuity, behind which, again, it is joined by the trans-
palatine. It terminates posteriorly i in a slender prolongation which
underlies the lower border of the jugal, and nearly reaches the
anterior end of the squamosal. Immediately within the alveolar
region, throughout its wholo extent, there is a deep groove similar
to that seen in the premaxille.

The faeial surface of the maxilla, like that of the premaxilla, is

pWol. 53-4 OF THE SKULL OF A PLIOSAUR. 183

roughened and pitted by many foramina. Internally it is bounded
by the premaxilla and the nostril, of which it forms the outer
margin. Posteriorly it appears to meet the nasal (?), supra-orbital,
and lachrymal.

The arrangement of the bones in the upper surface of the skull is
difficult to determine with certainty, owing to the crushing that has
taken place.

The fused parietals (fig. 2, p. 181, pa.) form a high massive
crest between the temporal fossz ; posteriorly they widen out to a
considerable degree, and no doubt their outer angles joined the upper
rami of the squamosals, which in the present specimen have been
dislocated in such a way as to overlap the hinder portion of the skull,
The inferior borders of the parietals slope outward so as to form a
roof to the brain-case ; anteriorly they unite with the expanded upper
end of the epipterygoid. The boundary between the parictals and
frontals is not clearly defined, and probably the bones were, in fact,
anchylosed. There are, however, traces of the suture between them
on the sides of the large pineal foramen ‘about 5 cm. in length),
the walls of this opening being formed by both these elements.

About 2 em. external to the pineal foramen there is a suture
dividing from the frontals and (?) parietals a bone which is clearly
the post-frontal. Anterior to this, and lying immediately external
to the frontal, thereis a long, narrow bone, apparently the prefrontal.
In front of this again there is another element which seems to be
continuous with a narrow strip which thrusts itself between the
external nares and the facial process of the premaxilla: this I
regard as the nasal. External to the nasal and prefrontal there is
a broad, thin plate of bone, the limits of which are not clear. This
bone overhangs the orbit, or at least the anterior part of it, and is
a supra-orbital.

The external nares (Pl. XII, ema.) are oval apertures,
about 5 cm. in length. They are separated from one another by
an interval of about 9°5 cm.,’ occupied by the facial processes of
the premaxilla and probably also by the nasals. They lie 57 em.
behind the tip of the snout, and, as in Peloneustes, some distance
behind the internal nares.

The antero-inferior portion of the orbital margin is formed by a
massive bone which joins the supra-orbital above, the maxilla and
probably also the jugal below: this element is no doubt a
lachrymal (7). It is produced inward, into a broad ridge which
forms an anterior wall to the orbit, and, curving upward and back-
ward, becomes continuous with a rounded crest on the inferior sur-
face of the cranial bones forming the inner limit of the orbit.

The form of the post-orbital and jugal (ju.), as well as
their relations to one another and to the ‘squamosal,’ are as in
Feloneustes.

The ‘squamosal’ (sq.) consists of an anterior ramus relatively
more slender than in the smaller form, and an upper ramus which no

* Probably somewhat exaggerated by crushing.

184 MR. C. W. ANDREWS ON THE STRUCTURE [May 1807,

doubt joined the outer ends of the parietals, but which has been
broken from its union with them and crushed down upon their dorsal
surface. In consequence of this dislocation the quadrate region is
much fractured, but it can be seen that the squamosal sends down @
broad plate which is closely applied to and apparently fused with
the posterior surface of the quadrate. This portion of the squamosal
terminates ventrally in a convex border which forms a rounded
ridge on the quadrate a short distance above the articular condyle
of that bone. This ridge is most prominent internally where,
between it and the upper border of the condyle, there is a deep
groove.

The quadrate (qu.) itself is extremely large and massive. The
body of the bone is concave from side to side anteriorly, convex in
the same direction posteriorly. As just noted, the posterior surface
is largely overlaid and concealed by the squamosal. ‘The distal end
forms an extremely large articular condyle, the form of which is
shown in Pl. XII. It will be seen that this articular surface is
divided by an oblique ridge into a smaller postero-internal and a
larger antero-external portion. From the inner border of the bone
immediately above the distal condyle there arises a strong process
directed inward and forward; this unites in an oblique suture with
the backward process of the pterygoid.

The teeth call for no special notice, since they agree precisely
with those described and figured by Lydekker.* The largest
specimen preserved is probably one of the large anterior (3rd
or 4th) maxillary teeth; its total length along the outside of
the curve is 23°5 em., length of crown 8°5 cm., and the diameter
at the base of the crown 2°8 cm. The smallest complete tooth
measures 6°2 cm. in length along the outside of the curve, the
crown occupying one-third of the length; the diameter at the base
of the crown is 1:1 cm.

The chief measurements of this skull are as follow :—

cm.
Length from tip of snout to occipital condyle ............-....666 112
se - 3 anterior angle of external nares ... 57
a a . 2 internal nares ... 36
s a a hinder end of facial process of
qorenmaxi aca tee .et es. cathe ease neeceeen eee 14
oun, AOLZEXbERTAL MATES )-\ doeeMe dese a HeSs(sivin cc « solgmndeow ree onto eam 5
Pei ramet SUABET TID GTATES) | Boe site c a alate eps acd a.sie ae die, atin hols eRe CRE 65
PP POSLEMIO’ PAlALME VACHILES 2... egies sanneo sense 11
Width of skull at quadrates (perhaps slightly exaggerated by
CHUSIMIIID A de ceccdteatiivaclesaaosshteetens nacceeeetaee 50
ie ,, at level of transpalatine bone ................0.00 48
i 7. ae middle of internal nares <....2. 055-20: eeee 19
es oy AEG TIGISTTO RRM Oo ROE cin 113
ts atawidest part OL premaxilla.........-a.00 seem 12
Or quadrate BM DICHLA TION: io.ch'cadpin cede csidigce owen es eee 12
Greatest diameter (transverse) of occipital condyle ............... 6:5

1 Quart. Journ. Geol. Soe. vol. xlvi. (1890) p. 49, pl. v. fig. 1.

J.Green del.et hth.

Quart. Journ. Geol Soc Vol. LIU P1.XI.

Mintern Bros. imp.
VRULI OF PLIOSAURUS.

Vol. 53. | OF THE SKULL OF A PLIOSAUR. : 185

EXPLANATION OF PLATE XII.
Skull of Pliosawrus ferox (Sauvage) from the Oxford Clay of Peterborough.
oa Nat. size.

1, From below. | 2. From above.

REFERENCE LETTERS.

col. = columella (epipterygoid). par.for. = parietal foramen.

é.na. = external nares. pas. = parasphenoid.
ina, = internal nares. p.f. = post-frontal.

ju. = jugal. pr.f. = pre-frontal.

Z, = lachrymal. p.mx. = premaxilla.

mx. = maxilla, p.p.v. = posterior palatine vacuities.

m.? = nasal (?). pt. = pterygoid.
0c.c. = occipital condyle. sg. = squamosal.
pal, = palatine. s.orb. = supra-orbital.
par. = parietal. vo. = vomer.

Discussion.

Mr. Lypexxer and Mr. Marr spoke, and the AurHor briefly
replied.

o.5.G. 8. No. 210. Oo

186 MISS G. L. ELLES ON THE SUBGENERA [May 1897, -

14. The Suscenera Pxrratoeraprus and CnpHaLogRaprvs. By
Miss G. L. Extes. (Communicated by J. KE. Marr, Esq., M.A.,
F.R.S., F.G.8. Read February 3rd, 1897.)

[Puares XIII. & XIV.]

ConTENTS.
Page
. Entrod Gems s ce cscaeatecane sabe cald@eckcn coche econ coe ee 186
EL. Definition of the’Subsenera © 2 4.0.0 /c22gs..-cs nese sae poeeeeeee 188
TELS Deseription of ble Spectres wc... <c 30. ds.else skeen eee 188
FV. General Conclusions | ios. s<c.cshenseceatsccueedenster eect tee eee 209

I. Inrropvuction.

Mocs confusion has arisen in our own country and on the Continent
with regard to the use of the names Petalograptus and Cephalo-
graptus for certain subgenera of Graptolites. Both names have
sometimes been employed for the very same species. Such an error
can only have arisen through ignorance of the detailed structure of
the type-forms. Thus, for example, in 1873 Lapworth’ gave Petalo-
graptus foliwm (His.) as the type of the subgenus Petalograptus.
In 1882 Tullberg, in his paper on the ‘ Graptolites described by
Hisinger,’ called it Cephalograptus folium, and classed it with
Cephalograptus cometa (Gein.). No wonder, then, that Geinitz,
writing later,’ adopted the safer plan of ignoring both subgenera, and
referred the species to the more embracing genus Diplograptus.

The object of this paper is to bring out the following facts :— :

(1) That both Petalograptus and Cephalograptus should be re-
garded as subgenera of the genus Diplograptus.

(2) That these subgenera are perfectly distinct, and can readily
be distinguished one from the other.

(3) That certain species should be referred to one or other sub-

enus.

: (4) The detailed structure of the various species, showing the
relationship existing between them. |

I have endeavoured to make my work on these subgenera as
complete as possible by examining specimens from many British
and foreign localities. Many of the British specimens were collected
by myself in the field, while others are to be found in the collections
of the Woodwardian Museum at Cambridge, and in the British
Museum (Natural History). During a recent visit to Sweden I was
enabled, through the great kindness of Dr. Térnquist, of Lund,
to study his magnificent collection of graptolites. This collection
not only contains specimens from almost every locality in Sweden
where graptolites are to be found, but is also rich in typical
forms from many other European areas (Bohemia, Thuringia, etc.).
From some Swedish localities I obtained specimens for myself, and

1 Geol. Mag. pt. il. p. 555.
2 *Graptoliten des k. Mineralog. Mus. Dresden,’ 1890.

Vol. 53.] PETALOGRAPTUS AND CEPHALOGRAPTUS, 187

Dr. Térnquist was good enough to supply me with material that
has been invaluable to me in my work.

Owing to the fact that the Swedish specimens are found in almost
every case in a better state of preservation than the British, I
have from them been able to make out with comparative ease many
important structural details which must otherwise have remained
obscure. ‘This applies especially to the details of structure of the
proximal end, which in the Swedish specimens is often preserved
in relief. It will, I hope, be evident from what follows that a
knowledge of the structure of the proximal end is of the greatest
importance for accurate specific determination of these forms.

HMistorical.—As early as 1851 Siiss' used the term Petalolithus
as a synonym for M‘Coy’s Diplograpsus, but it should be noted that
the forms which he considered typical of this genus were: P. palmeus
(Barr.), P. folium (His.), P. parallelocostatus (sp. nov.), P. ovatus

Barr.).

In * 968 Carruthers” recognized the peculiarity of the form
Diplograptus cometa (Geinitz, 1852), and suggested that perhaps it
should be made the type of a new genus. Acting on this sugges-
tion, Hopkinson founded the genus Cephalograptus for this form.°
He also recognized that the form was distinct from what he erro-
neously calls D. foliwm (His.).

In 1873 Lapworth, in his ‘Classification of the Rhabdophora,’ *
placed both Petalograptus (Siiss) and Cephulograptus (Hopk.) as
subgenera of Diplograptus (M‘Coy), and considered Petalograptus
folium (His.) as a type of the subgenus Petalograptus, and Cephalo-
graptus cometa (Gein.) as a typical Cephalograptus. He stated
that such subgenera are of value merely ‘ as enabling us to group
together, for convenience of reference, species having a certain
amount of similarity in their external features.’ But this ‘ simi-
larity in external features’ is accompanied by certain structural
modifications.

Accepting the definition of Diplograptus as given by Lapworth
(op. cit.), both Petalograptus and Cephalograptus must be included
in it. In structure also they follow, broadly speaking, the same
general plan. Hence they should, I think, be regarded as sub-
genera of that genus. But because they possess many characters
in common with all forms of Diplograptus, and yet have some
peculiar to themselves, I venture to think that these subgenera
have great value as representing a distinct phase in graptolite
phylogeny. The Petalograpti are the closest to those forms of
Diplograptus which we regard as normal; these are included in
Lapworth’s Orthograptus and Glyptograptus.

It will be shown in the sequel that Petalograptus must have been
derived from Orthograptus, and Cephalograptus from Petalograptus,
as the result of development along certain lines. Cephalograptus
may be regarded as the most extreme Diplegraptus-type.

1 «Ueber Bohmische Graptolithen.” 2 Geol. Mag. p. 131.
* See Journ. Quek. Microsc. Club, 1869. + Geol. Mag. pt. ii. p. 555.
02

188 MISS G. L, ELLES ON THE SUBGENERA _ [ May 18907,

ILI. DEFINITION OF THE SUBGENERA.
PETALOGRAPTUS.

Rhabdosoma foliiform. Sicula embedded, completely visible only
on one side of the rhabdosoma. Proximal end somewhat protracted,.
never rounded. Thece of various lengths, all with the same general
characters. Long tubes with concave apertures, situated obliquely
to the general direction of the rhabdosoma. Septum complete or
partial. Type, Petalograptus folium (His.).

To this subgenus may also be referred:— |

Petalograptus palmeus (Barr.); P. p. var. latus(Barr.); P. p. var.
tenuis (Barr.); P. p. var. ovato-elongatus (Kurck) ; P. ovatus (Barr.) ;
P, minor (sp. nov.).

CEPHALOGRAPTUS.

Rhabdosoma fusiform or triangular. Sicula exposed, completely
visible on both sides of the rhabdosoma. Proximal end very
protracted. Thece long, tubular, with concave apertures almost
perpendicular to the long axis of the rhabdosoma. Septum incom-
plete. Type, Cephalograptus cometa (Geinitz); also C. petalum,.
sp. Noy.

The species are particularly characteristic of the Middle and
Upper Birkhill Shales ; some survive into the Lower Gala-Tarannon,
and one appears to be confined to that horizon.

I now proceed to a description of the species, beginning with the
type-species of the subgenus Petalograptus.

III. Descriprion oF THE SPECIES.
Subgenus Petalograptus.

PETALOGRAPTUS FoLIUM (Hisinger). (Pl. XIII. figs. 1-5.)

1837. Prionotus foliwm, Hisinger, ‘Lethza Suecica,’ Suppl. p. 114, pl. xxxv. fig. 8.
1843. Prionotus foliwm, Portlock, ‘ Geol. Report Londonderry,’ p. 321, pl. xx. fig. 5.
: 1851. Non Diprion foliwm, Harkness, Quart. Journ. Geol. Soc. vol. vii. p. 63, pl. i.-
g. 12.
1851. Non Diplogr. foliwm, Scharenberg, ‘ Ueber Graptolithen,’ p. 16, pl. i. figs. 18,
14, pl. ii. figs. 15, 16.
cares Non Prionotus folium, Boeck, ‘ Bemerkninger angaaende Graptolitherne,”
pl. 1. fig. 8.
1868. Non Diplogr. foliwm, Nicholson, Quart. Journ. Geol. Soc. vol. xxiv. p. 524,
pl. xix. figs. 4-7.
1868. Non Diplogr. foliwm, Carruthers, ‘Syst. Position of the Graptolites,”
Intellectual Observer, xi. pl. ii. figs. 4a-c, 5 a-d.
1876. Non Diplogr. folium, Lapworth, ‘Grap. of Co. Down,’ Proc. Belfast
Naturalists’ Field Club, p. 183, pl. vi. fig. 16.
oe Diplogr. foliwm, Tornquist, Geol. Foren. Forhandl. vol. v. p. 442, pl. xvii.

1882. Cephalogr. folium, Tullberg, K. Svenska Vet. Akad. Handl. vol. vi. no. 13,,
p. 16, pl. i. figs. 15-19.

1890. Diplogr. folium, Geinitz, ‘Graptoliten des k. Mineralog. Mus. Dresden,’
p- 26, pl. A. figs. 44-46,

Vol. 53.] PETALOGRAPTUS AND CEPHALOGRAPTUS, 189

This species, though very well known in Scandinavia, seems
never to have been clearly recognized in this country. It has most
frequently been confounded with Petalograptus palmeus (Barr.). It
may be said to show some general relationships to that species, but
it has peculiar characteristics which mark it out as a perfectly
distinct form. .

Tullberg, in his paper on the ‘ Graptolites described by Hisinger,’
has grouped it with Cephalograptus cometa (Gein.) in the sub-
genus Cephalograptus (Hopk.). To this I cannot agree. In the
development of the earliest thece, in the position of the sicula, and
in the relation of the thece to the sicula, Petalograptus folium is
far more closely allied to Petalograptus palmeus (Barr.) than to
Cephalograptus cometa (Gein.).

Hisinger’s original figures were generalized from many imperfect
Specimens, but during my recent visit to Sweden I had the oppor-
tunity of studying more perfect specimens of the species, collected
at the same time as Hisinger’s types.

The forms from different localities vary within certain narrow
‘limits as regards width, but the difference is so slight that the forms
ean hardly be considered worthy of being ranked as distinct varieties.
The circumstance of variation in width depends merely on the
amount of curvature of the thece. If the curvature is rather more
pronounced the width is increased.

Some of my specimens are in half-relief, and exhibit details of
Structure which have not hitherto been noticed.

Structure of the Proximal End.—The sicula is somewhat slender,
but is short compared with the great length attained by the thece.
It never exceeds +4, inch in length, and is usually rather more than
7g inch long (about 2 mm.).

It certainly possessed an apertural spine, though this is not seen
in all specimens, since it would seem to have been easily broken off.
From a short distance above the base of the sicula and on the same
side as the apertural spine the ‘ primordial bud’ is produced. ‘This
gives rise to the first theca of the primordial series, and also to the
connecting-canal, from which the first theca of the second series is
‘developed.

Here I must explain a few of the terms of which I shall make use
in the following pages. The term ‘primordial series’ is used in
Térnquist’s sense to denote all the thece lying on the same side of
the sicula as the first. For the sake of brevity these are repre-
sented in the tables by the following symbols: 1’, 2}, 3°, etc. ;
while those which lie on the opposite side are termed the ‘ second
series,’ since they contain the second theca. These are denoted by
the symbols 1’, 2”, 3°, etc. That side of the rhabdosoma on which
the sicula is completely visible is termed the ‘ obverse’ side. In such
an aspect the first theca of the primordial series (1’) is always on
the left side. The other aspect of the rhabdosoma is termed the
‘reverse’ side. The ‘ connecting-canal’ is a convenient term to use
for the canal, at or near the base of the sicula, which connects the

190 MISS G, L. ELLES ON THE SUBGENERA [May 1897,

first theca of the primordial series with the first of the second series.
Dr. Holm has used it in this sense. It is completely visible on the
reverse side of the rhabdosoma. The later that theca 1° develops
from theca 1, the shorter is the connecting-canal. If 1° does not
arise till after theca 1’ has grown past the apex of the sicula, the
connecting-canal is practically reduced to nothing. It is generally

Two early stages in the development of Petalograptus folium (His.).

oo --nen--------Virgule.

---------Th, 12,

1% Theca --. :
; aut hele:
, 20t complete. not complete,"

wenn SG
wWicula, e
Tia: Sicula..
tee =

Avertural “Primordial “Primordial ™

Pine of ----==—n--- bud. Apertural Eas
_Sicula. PUNE Of; Nineteen et,

Stcula,.
1 [Greatly enlarged. | 2

indicated by the growth-lines running in a direction different from
those of thece 1 and 1’.

In this species the sicula is never completely enveloped by the
thecee of the rhabdosoma, even at its apex ; it is visible for its entire
length on the obverse side. In this position it appears to be free
on the right side for about 4 of its length; after that it occupies a
position midway between thece 1! and 1°. In the reverse aspect.
only the base of the sicula and a very small portion of the side are
visible, the rest being here concealed by the connecting-canal and
by the initial part of the second and subsequent thece.

The first theca of the primordial series seems to grow both
upwards and downwards in a manner similar to that described by
Dr. Wiman as characteristic of the genus Diplograpius. The
downward-growing part in this case extends a little way below the
base of the sicula.

The first theca of the primordial series is usually rather less than
three times as long as the sicula. It attains a length just short of
z ch; the thece developed later are slightly longer. All have a.
distinct concave curvature; proximally the apertures overlap each
other from about 4 width, but distally the overlap is less. The
width of the rhabdosoma opposite the aperture of the first theca of the

Vol..53.| PETALOGRAPTUS AND CHPHALOGRAPTUS. 191

primordial series is 3 inch. Exceptionally it is as much as } inch.
Below that point the rhabdosoma tapers somewhat abruptly.

Character of Mature Rhabdosoma.—The greatest length attained
by the mature rhabdosoma is 1 inch. The width increases rapidly
up to the 4th theca (4'), but afterwards the increase is so slight
and so gradual that the sides appear approximately parallel for a
greater or shorter distance, according to the length of the rhabdo-
soma. The maximum width attained is about inch. Some forms
barely attain ;2, inch, while one form which I saw in Dr. Tornquist’s
collection at Lund attained its maximum width opposite theca 4’,
and then again diminished near the distal end: the resulting form
resembling that variety of P. palmeus (Barr.) to which Kurck has
given the name ovato-elongatus.

The thece of the middle of the rhabdosoma are slightly longer
than the two earliest thece; they are about 7 inch long, distally
they are less, and at the actual extremity are quite short. The
relation between thecal length and breadth is as 6: 1.

The thece are alternate; they are tubular, and appear to be
square in section. The apertures are slightly concave; they are
perpendicular to the long axis of the theca, and oblique to the
general direction of the rhabdosoma, except at the distal end. They
are often striated parallel to the aperture; these strize are growth-
lines. There are twenty-five apertures in the space of linch. The
outer wall of each theca is free for a small fraction of its length,
except at the distal extremity. The angle at which the thece are
inclined to a median line varies; itis about 5° at the proximal end,
it then increases to about 20° in the middle of the rhabdosoma, and
again decreases to 5° near the distal end. The thece are all con-
cavely curved, but not equally so. The curve is greatest in the
earliest thece, but subsequently diminishes, giving to the whole
rhabdosoma the characteristic foliate appearance to which it owes
its name.

The appearance of rounding off at the distal end is due to decrease
in curvature and diminution in length of the thece in that direction.
In no specimen have I seen any indications of the presence of a
septum, and I certainly do not think that one can ever have been
present. One reason in support of this view is the quite irregular
course taken by the virgula from its point of origin at the sicula-
apex to the point at which it emerges from the rhabdosoma at the
distal end. This irregularity would seem to point to its having
been perfectly free in the rhabdosoma, and I cannot believe that
the appearance, which is the same in many differently preserved
specimens, is merely a result of the conditions of preservation. The
virgula is often distally prolonged for a considerable length, and not
infrequently is split at one or more points along its length. It
must have been very near the obverse surface of the rhabdosoma
for at least the earliest part of its course.

The following table records the measurements of a few typical
forms :—

192 MISS G. L. ELLES ON THE SUBGENERA [May 1897,

Spec. | Locality. | Lgth. ws oe a Opp. . L. 14. 12| Max. | 82-,%

ap. inch
A. |Belcraig...) 3 = <- 3 1 | 42) 41 | 24
C1. |Kallholn...) 3 4 3 i np it 1| 25
O07. - a 3 tc ve Te re cs
D. » 4 7 1 3a Te z x | 26
E. ” “ 3 te a 15 a x | 25
F, ” 3 3 1 ma: —4 | +3] +3] 25
G. |Kongslena| # Pa - = * a 1
I. |Beleraig...) 4 $ Bs he" +
K. |Duffkinnell| & fi 2S age 1 24

Notr.—-The sign + in the above table is intended to represent that
the measurement is slightly in excess of the figure which it precedes; the
sign — denotes that the measurement is slightly below that figure. Thus
+4 means that the measurement is more than } inch, and —} that it is less
than } inch,

General Characters.—In summing up the chief characteristics of
this species it will be convenient to compare it with Petalograptus
palmeus (Barr.), the form with which it has so often been confounded
by British authors.

(1) The characteristic foliate form is more marked than in
P. palmeus (Barr.).

(2) The form attains a greater width than P. palmeus.

(3) The proximal end is far more protracted than in the latter
species.

(4) The thece in P. foliwm (His.) are much longer, the angle of
inclination is less, and there are fewer in the space of an inch.

(5) There exists quite a different ratio between the length of the
sicula and the length of the thece.

Horizon.—In the Moffat district P. folium (His.) occurs in a
band of black shale distinctly below the horizon of C. cometa (Gein.).
In the Lake District it occurs in Marr and Nicholson’s zone of
M. convolutus (His.), a zone which occupies a similar position.’
This species also occurs in a band below the C. cometa-zone in the
Rastrites-Shales of Kallholn,” Furudal (Dalarne), Kongslena ( Vester-
gotland), and at Rosténga, Kiviks Esperod, and Tommarp in Skane.

The species is also known in the ‘ colonie Haidinger’ in Bohemia.

British Localities —Moffat District: Dobb’s Linn, Beleraig Burn,
Duffkinnell Burn, near Wamphray. Lake District: Skelgill.

1 See Quart. Journ. Geol. Soe. vol. xliv. (1888) p. 711.

2 Geinitz, ‘Graptoliten des k. Mineralog. Mus. Dresden,’ 1890, states that
Hisinger’s types came from Fagelsang in Skane. This is an error; the original
specimens came from Furudal in the province of Dalarne.

Vol. 53.] PETALOGRAPTUS AND CEPHALOGRAPTUS. 193

PETALOGRAPTUS PALMEUS (Barr.).

1850. Graptolithus palmeus, Barrande, ‘Grap. de Bohéme,’ p. 59, pl. iii. figs. 1-7.
1851. Petalolithus palmeust parallelocostatus, Stiss, ‘ Ueber Bohmische Grapto-
lithen,’ pp. 20, 21, pl. vil. figs. 1, 2, 4.
1852. Diplograptus palmeus, Geinitz, ‘ Die Graptolithen,’ p. 21, pl. i. figs. 5-19.
1853. Diplograptus palmeus, Richter, Zeitschr. d. Deutsch. Geol. Gesellsch. vol. v.
p. 455, pl. xu. figs. 8-10.
‘ 1876-1880. Diplograptus palmeus, Zittel, ‘Traité de Paléont.’ vol. i. p. 305,
. 214, d,e.
*i880- 81. Diplograptus palmeus, Linnarsson, Geol. Foren. Forhandl. vol. v. p. 522,
pl. xxiii. figs. 26-28.
1887. Diplograptus palmeus, Tornquist, Geol. Foren. Férhandl. vol. ix. pp. 478,481.
1890. Diplograptus palmeus, Geinitz, ‘Graptoliten des k. Mineralog. Mus.
Dresden,’ p. 26, pl. A. figs. 39, 41-43.
1893. Diplograptus palmeus, Tornquist, ‘Structure of some Diprionide,’
K. Fysiogr. Sallskap. Handl., Lund, vol. iv. p. 9, figs. 29-35.

This species has been very generally recognized, but the details
with regard to the structure of its proximal end have never received
proper attention. The form which Tornquist referred to this species
in 1893 (op. supra cit.) cannot, I think, be retained in it, as it differs
in many important particulars, and must, in my opinion, be regarded
as a distinct species.

I can find no evidence in support of the separation of P. parallelo-
costatus from the true P. palmeus (Barr.). The characters upon which
Siiss founded this species have been shown to belong equally to
P. palmeus (Barr.). Therefore I think that the species must be
abolished.

Barrande, in his work on the Graptolites of Bohemia, suggested
two varieties of the species palmeus. These varieties were based on
the difference in width of the rhabdosoma in different individuals,
and were termed respectively (1) var. lata and (2) var. tenwis. He
does not describe these varieties in detail; but from his description of
Petalograptus palmeus we must, I think, conclude that he meant the
forms that exceeded $ inch (38 mm.) to be termed var. Jatus, and
those which were less than ;4 inch (2 mm.) to be called var. tenuis.
Hence it follows that the actual specific name Petalograptus palmeus
(Barr.) must be restricted to those forms which exceed 5), inch in
width and which do not exceed 3 inch. Lach of these three forms
has a slightly different range in time.

In addition to the three forms mentioned above there exists one
to which Kurck has given the name ovato-elongatus.

He ranked it as a distinct species, but, for reasons which will be
given later, I think that it cannot be regarded as more than a
variety. Barrande recognized the form, but did not give it a separate
name. :

I now proceed to describe in some detail the structure of the
different forms of P. palmeus (Barr.).

PETALOGRAPTUS PALMEUS (Barr.) (restricted). (Pl. XIY. figs. 1-4.)

Structure of the Prowimal End.—The sicula is fairly long, and is
broader than that of P. foliwm (His.). It is usually rather less than
ys inch long (about 2mm.). It reaches up to the third theca of each

194 MISS G. L. ELLES ON THE SUBGENERA [May 1897,

series. The sicula is very long relatively to the length of the thece,
compared with P. folium (His.). It is furnished with an apertural
spine, which seems to have been particularly stout and strong in the
forms which lived in the Gala-Tarannon times, but which is also
found in the forms of other horizons, All the Gala-Tarannon
specimens have the spine exceedingly well-preserved, even when
the fossils are not very clear in other respects. But in the case of
forms occurring at lower horizons the spine seems to have been broken -
off altogether in some specimens, while in others only a small
portion of it remains.

The first theca of the primordial series arises at the base of the
sicula and grows outward almost at once, making a very decided
concave curve. There appears to be no downward growth in this
case below the base of the sicula. The second theca (1°) arises very
much as in P. foliwm (His.) except that the curvature is greater and
takes place sooner than in that species, so that the sicula is not free
for so large a fraction of its length on the right side. Viewing the ~
rhabdosoma from the obverse side, the sicula is free for rather less
than 3 of its length ; on the reverse side only the base is seen to the
left, the rest being concealed by the connecting-canal, the initial
part of theca 1°, and subsequent thecal bases. The theca = here
follows the outline of the sicula for a short distance before curving
outward, so that less of the sicula is seen on the reverse than on the
obverse side. The two earliest thece are rather less than jo inch
in length, and are equally curved, giving a symmetrical appearance
to the proximal end. Subsequent thece are not so much curved as
the earliest ones. The angle at which the thece are inclined 18:
approximately constant in the narrower forms at 35°, but in the
wider forms the angle becomes steeper towards the distal end, though
it never diminishes below 20°. Taken as a whole, the proximal end
may be said to be short and blunt.

Character of Mature Rhabdosoma.—The mature rhabdosoma gene- —
rally attains the length of about 1 inch, but in some specimens has
been known to be as much as 13 inch long. The maximum width
is attained almost at once; it varies between ;4 and § inch. The
sides are parallel. This is noticeable even in quite young forms,
which maintain a constant width right up to the distal end. That
end may be truncate or slightly rounded.

The thecze are alternate; they consist of short tubes three times
as long as wide, whose outer wall is free for a small fraction of its
length near the distal end, but at the proximal end the tubes are often
in contact throughout their length. The thece are adorned with
lines of growth parallel to the aperture. The apertures are slightly
concave, and are perpendicular to the long axis of the thece; they
overlap somewhat, at the proximal end, but this diminishes distally.
There are 32 thecal apertures in the space of an inch.

There appears to have been a continuous septum throvgh the
rhabdosoma. The virgula is, as a rule, very conspicuous in all
_ Specimens; it is usually prolonged distally and is often split at

me

Viols5 3. PETALOGRAPTUS AND CEPHALOGRAPTUS. 195

various points along its length, both inside and outside the rhabdo-
soma (see P]. XIV. fig. 3). In this case as in all others, the sicula is
completely exposed on the obverse side ; the virgula, for the earlier
part of its course, must run very near the obverse surface. Barrande
suggested that the appearance of splitting might be due to a process
of exfoliation of the component layers, which could come about only
after the death of the animal.

General Characters. This species is characterized by—

(1) The short and abruptly-terminated character of the proximal
end.

(2) Length of the sicula relatively to the theca.

(3) Short thecz and the ratio between their length and breadth.

(4) Relative length and width of rhabdosoma as a whole.

Horizon.—The species seems to have had a long range. It ranges
in Britain from the bottom of the Middle Birkhill Shales up into the
Lower Gala-Tarannon beds. In Scandinavia it occurs immediately
above the zone corresponding to that of Diplograptus vesiculosus
(Nich.) at. Rosténga, and is common in the Rastrites-Shales of
Tommarp, Bollerup (Skane), and Kongslena (Vestergotland). It
occurs with M. turriculatus (Barr.) at Klubudden (Vestergotland), and
with M. turriculatus and M. eaigquus at Osmundsberg (Dalarne).

It occurs also at similar horizons at Berown and Zelkovice in
Bohemia, and in the Rastrites-Shales of Heinrichsruhe in Thuringia.

British Localities.—Moffat District : Dobb’s Linn, Belcraig Burn,
Garple Linn, etc., Lundhope-on-Yarrow. Lake District: Skelgill,
Browgill, Pull Beck, Kentmere, Ashgill. Wales: in Birkhill and
Tarannon Shales at Conway.

PETALOGRAPTUS PALMEUS, var. LATUS (Barr.). (PI. XIV. figs. 5-8.)

Structure of the Proximal Hnd.—In nearly all the details of
structure of the proximal end P. palmeus, var. latus, agrees with
P, palmeus (restricted). The sicula is about the same length, and
reaches up to the third theca of the primordial series, as in that form.
It has an apertural spine, although this is but rarely preserved.

It differs in the fact that the earliest thece make a greater
curve from their origin and are rather longer, so that the width of
the rhabdosoma is increased.

Character of Mature Rhabdosoma.—This variety very seldom
attains a length as great as that of the longest forms of P. palmeus
(restr.) ; it is most commonly found with a length of about 4 inch.
The maximum width, generally nearly 1 inch, is attained at once
and continues quite up to the distal end, which has a broadly trun-
cate form in most specimens, but occasionally is somewhat rounded.

The thece are alternate ; they are about three times as long as
wide, and are fully 4 inch long, except at the distalend. The aper-
tures are slightly concave; they are perpendicular to the thecal length,

196 MISS G. L. ELLES ON THE SUBGENERA | May 1897,

and oblique to the long axis of the rhabdosoma. ‘There are about
36 thecal apertures in the space of an inch. The thece are
inclined at their origin at the proximal end at an angle of about
A5°, but curve very distinctly after this in an outward direction.
The angle of inclination changes uniformly from the proximal up to
the distal end, where it is about 20°. There appears to be a con-
tinuous septum in this variety, but its course is rather irregular (see
‘Pl. XIV. fig. 8). The virgula is conspicuous, is distally prolonged,
and may be split as in P. palmeus (restricted).

General Characters.—This variety differs from P. palmeus (restr.)

in

(1) Greater width.

(2) Greater number of thecal apertures in the space of an inch.

(3) The greater angle at which the thece are inclined at the
proximal end.

(4) The greater curvature of the same thece.

Horizon.—This variety has a rather shorter range than P. palmeus
(restr.). It first appears about the middle of the zone of M. gregarius
(Lapw.), and is most abundant throughout the middle and upper
parts of that zone. I have never found a specimen in the Lower
Gala-Tarannon beds. It seems to be specially characteristic of the
Middle Birkhill Shales.

It occurs in Scandinavia in the Rastrites-Shales of Tommarp
and Bollerup in Skane, at Kongslena in Vestergotland, and at
En§n in Dalarne.

In Bohemia it occurs with M. proteus (Lapw.) at Litohlay, and
with M. finbriatus at Berown and Zelkovice.

In Thuringia it has been found in the Rastrites-Shales of Riickers-
dorf and Heinrichsruhe.

British Localities —Moffat District: Dobb’s Linn, Garple Linn,
etc., wherever the M. gregarius-zone is typically developed. Lake
District: Skelgill. Ireland: Coalpit Bay, Co. Down.

PETALOGRAPTUS PALMEUS, var. TENUIS (Barr.). (PI. XIV. figs. 9-10.) |

Structure of the Proximal End.—The details of the structure
of the proximal end are similar to those in P. palmeus (restr.).
The sicula is perhaps a very little shorter than in the two
forms previously described. It is furnished with a long apertural
spine.

The earliest thecze are shorter than in P. palmeus (restr.), and are
almost straight; they are also much broader in proportion to their
length.

The sicula is rather more than 4 inch long. ‘The first theca is
the most curved ; it is about =4; inch in length.

Character of Mature Rhabdosoma.—This form is often small,
but it may be as much as 4 inch in length. The width of ,1, inch
is maintained throughout its length. The thece are alternate; they

ot
Vol. 537) PETALOGRAPTUS AND CEPHALOGRAPTUS. 197

are short tubes =1 inch long, and are twice as long as broad. Their
outer walls are free for a small fraction of their length. The theca
are often seen to be adorned with striz parallel to the direction of the
apertures, which are concave and perpendicular to the long axis of
each theca, but oblique to the general direction of the rhabdosoma
(Pl. XIV. fig. 10). The thece are widest at their apertures; they
are inclined at a constant angle of about 35°. The earliest thece
are curved very slightly, but subsequent ones are almost straight.
There are about 36 apertures in the space of an inch. A septum
is present, but it seems to be only a partial one. The virgula is
often distally prolonged.

General Characters.—This variety differs from P. palmeus (restr.),
(1) In its extreme narrowness ;
(2) In the number of thecal apertures in the space of an inch ;
(3) The shortness of the thece and the absence of curvature ;
(4) The proportions of the thece.

Horizon.—This variety ranges from the top of the zone of M.
gregarius (Lapw.) into the Lower Gala-Tarannon Shales.

It occurs with M. convolutus in Scandinavia, at Tommarp, Rost-
anga, Kongslena, and Enan. In Bohemia it occurs with an Upper
Birkhill fauna at Berown, Zelkovice, etc., and with M. turriculatus
at Litohlav.

It also occurs in the Aastrites-Shales of Heinrichsruhe in
Thuringia.

British Localities——Moffat District: Dobb’s Linn, Belcraig, ete.
Lake District: Skelgill, Pull Beck. Wales: Lower Tarannon-
Shales, Conway.

P. PALMEUS, Var. OVATO-ELONGATUS (Kurck). (PI. XIV. figs. 11-14.)

1850. Diplograptus palmeus, Barrande, ‘ Grap. de Bohéme,’ i. pl. iii. fig. 7.

1852. Petalolithus palmeus, Siiss, “Ueber Bohmische Grapt.’ pl. viii. fig. 1.

1868. D. palmeus, Nicholson, Quart. Journ. Geol. Soc. vol. xxiv. p. 523 & pl. xix.
figs. 2, 3. j

1876. D. palmeus, Lapworth, ‘Cat. Western Scottish Fossils,’ pl. i. fig. 27.

1881. Cephalograptus ovato-elongatus, Kurck, ‘Nagra nya Graptolitarter fran
SkAne,’ Geol. Foren. Férhandl. vol. vi. p. 303, pl. xiv. fig. 10.

1890. D. ovato-elongatus, Geinitz, ‘Graptoliten des k. Mineralog. Mus. Dresden,’
pl. A. fig. 40.

When Kurck described this form in 1881, he acknowledged that
he was ignorant of any of the details of the structure of the proximal
end. Had he been acquainted with these he would surely have
detected the very close relationship existing between this form and
Petalograptus palmeus, var. latus (Barr.), and would probably then

have described the form merely as another variety of P. palmeus
(Barr.).

Structure of the Proxumal End.—The sicula is distinctly seen in

many specimens ; it is rather less than +4, inch long and is placed

exactly as in P. palmeus, var. latus (Barr.), except that in this

198 MISS G, L, ELLES ON THE SUBGENERA [May 1897,

case it scarcely reaches the level of the base of theca 3%. The
earliest thece are strongly curved, as in P. palmeus, var. latus, and
in all details of development ‘are precisely similar. The earliest
thecze are rather shorter than those subsequently developed.

Character of Mature Rhabdosoma.—The length of the mature
rhabdosoma is generally between 3 and 1 inch. The form varies
within certain limits in the relative amounts of what may be
termed the ‘ ovate’ or the ‘ elongate’ parts.

Asin P. palmeus, var. latus (Barr.), the maximum width is attained
almost at once, usually opposite the aperture of the second theca of
the primordial series. The width attained is 4 inch, the same as in
var. latus. Thus, in all the early stages, itis very hard to distinguish
P, p. var. latus from P. p. var. ovato-elongatus. The maximum width
may be maintained for a short distance if the ‘ ovate’ part is long,
or else a diminution in width takes place directly.

The decrease is sometimes gradual, sometimes rather abrupt.
This decreased width is then maintained up to the distal end.

The thece are alternate ; they are ;4, inch long, and four times as
long as wide in the ‘ ovate’ part, but rather less near the distal
end. The thecee are widest at the apertures, and frequently show
growth-lines. The apertures near the proximal end are almost
parallel with the long axis of the rhabdosoma, but become more
oblique towards the distal extremity. Near the proximal end the
thecee are inclined at 45°, and describe a decided curve as they
grow outward, but the angle of inclination diminishes to 20° near
the distal end, and the thece throughout the ‘elongate’ part are
almost straight. Hence the form is attained by an alteration in the
amount of curvature and inclination, accompanied by a slight
diminution in the length of the thece.

There seems to have been a continuous septum (see Pl. XIV.
fig. 14).

General Characters.—The form of the mature rhabdosoma is
sufficient to distinguish it from all other varieties of P. palmeus —
Barr.).
Horizon.—The species has a long range. It appears early in the —
zone of M. gregarivs (Lapw.), and survives into the Lower Gala-
Tarannon beds.

It is common in the Lastrites-Shales of Tommarp, Bollerup, and
Klubudden, and has been recorded from Zelkovice, Berown, etc., in
Bohemia.

British Localities.—Moffat District: Dobb’s Linn, Garple Linn,
etc. Lake District: Skelgill, Mealy Gill. Wales: Conway
(Tarannon Shales).

Nol 53: PETALOGRAPTUS AND CEPHALOGRAPTUS. ° 199

TABLE OF MEASUREMENTS OF DIFFERENT VARIETIES OF
P. PALMEUS (Barr.).

*
, | L. of | W. opp. | Max. Irhecat | No. of | No. to .
No.| Species. | Lngth. ‘| sicula. ap. 1'. | width.|length. thecz.| inch. pealiy:
a. | P. palmeus...| % fs jos | - 32 | Conway.
1>, | P. palmeus.... & |—ds vy ty Te wee Zelkovice.
2. | var. tenuis...) 5 oe ot ir ee aes: 36 | Belcraig.
: Dobb’s

3. | var. tenuis suis $ as oy is ot 11 36 { Linn.
6°. | var. datus ...| 4 42 z +35 26 36 i

10. var. datus ....\4+3 |—Z L 1 \+45 23 36 a
Pe ee \ SN aa 3 Tz & |+7s 26 36 ”

hp sed ens amps | Abe x abeae |<... ho kw \eSealaal

PETALOGRAPTUS ovATUS (Barr.). (Pl. XIV. figs. 15-16.)

1850. Graptolithus ovatus, Barrande, ‘ Grapt. de Bohéme,’i. p. 63, pl. iii. figs.

1851. Petalolithus ovatus, Siiss, ‘Ueber Béhmische Grapt.’ p. 21, ‘pl. vill. Ee

1852. Diplograpsus ovatus, Geinitz, ‘ Die Graptolithen,’ p. 20, pl. 1. figs. 3 &4.

1890. Diplograptus ovatus, Geinitz, ‘ Graptoliten des k. Mineralog. Mus. Dresden,’
p. 25, pl. A. fig. 37.

With the exception of one very doubtful form from the Tarannon
Shales of Conway, North Wales, I have never seen a British specimen
that could correctly be referred to P. ovatus (Barr.). As far as our
present knowledge goes, the typical form at any rate does not seem
to have been recognized outside Bohemia.

The species is exceedingly characteristic, and can readily be dis-
tinguished from all other forms; but, in spite of this, many young
forms of other species have been erroneously referred to it. The
specimens from Bohemia in the British Museum (Natural History)
have had for some unaccountable reason Barrande’s original labels
corrected, and now bear the name D. foliwm (His.), though they are
typical forms of P. ovatus (Barr.), and bear little or no resemblance
to Hisinger’s species.

Structure of the Proximal End. ane sicula has a peculiar
shape ; it is broad, curved, and about ;4, inch long. It reaches up
to the third theca of each series, at is furnished with a short
apertural spine. The earliest thecz are both very curved ; the first
of the primordial series arises near the base of the sicula, and is so
much curved that the aperture is almost on a level with the point at
which the ‘ primordial bud’ arose. The second theca (1’) is very
nearly as much curved. Sometimes these two earliest thece are
very short, at others they do not differ greatly in length from those
thecz which arise later.

200 MISS G. L. ELLES ON THE SUBGENERA [May 1897,

On the obverse side the sicula appears to be free for 4 of its
length on the right side, and the same amount is seen on the reverse
side.

Character of the Mature Rhabdosoma.—The species varies some-
what in shape; it is typically as broad as it is long, but in some
specimens it is rather longer, and the shape then is a broad oval. I
have never seen a specimen that exceeded 7 inch in length. The
width varies in different specimens from 3 to 7 inch.

Near the proximal end the thece are alternate ; where the thece
become horizontal they are almost opposite, but the alternation is
again visible at the distal end. The thecz are ;4 inch long except
at the distal extremity, and in typical forms are four times as long
as they are broad; in the more oval forms the dimensions are
slightly less. The thece are widest at their apertures, and overlap
somewhat. The apertures are concave, and near the proximal
end they are directed downward, but towards the distal end this is
not so marked. ‘There are about 42 apertures in the space of 1 inch.
The angle of inclination of the thece varies greatly at different
points along the length of the rhabdosoma. It changes as follows :—
70°-90°-55°-45°. The thece are all concavely curved, but the
curvature is greatest near the proximal end. The virgula is pro-
longed beyond the distal extremity.

When the form is longer in proportion to its width, this seems to
be due to the fact that there is a difference in direction of growth
of the thece ; fewer thecze are curved downward, so the upward
inclination begins earlier.

General Characters.—This species differs from all others
(1) In the various angles at which the thece are inclined in
different parts of the rhabdosoma ;
(2) In the number of thecee ;
(3) In having the apertures of the thecz recurved towards the
_ base.

Horizon.—This species occurs in Bohemia in shales with WM. tur-
riculatus (Barr.), and M. ewiguus (Nich.). These beds are probably
the equivalents of our Lower Gala-Tarannon beds.

British Locality.—(?) Conway, North Wales.

TABLE oF MEASUREMENTS.

No. |Lngth. aut ean ae ee tec Locality.

Ce ae vr a 1 J+, 22 | Zelkovice, Bohemia. |
Quod Oe ts Tz t Tz 24 ; 93
e.../+ 3 +4 Te 16 ” ”

d...| & Telos TZ 15 s» Y

é. % 1 5 1z 22 ” ”

Woli53.1 PETALOGRAPTUS AND CEPHALOGRAPTUS. 201

PETALOGRAPTUS MINOR, sp. nov. (Pl. XIV. figs. 17-21.)

= Diplograptus palmeus, Tornquist, ‘Structure of some Diprionide.’

This small species has usually been regarded as merely a young
stage of P. palmeus (Barr.), or P. palmeus, var. latus (Barr.), but it
differs from these in many important particulars.

I had noted this form some little time previous to my visit to
Sweden, but through lack of good material I did not like to venture
upon its description. While in Sweden I was fortunate enough to
see several excellent specimens preserved in relief ; and having since
my return examined some better material obtained from the Moffat
district, I no longer hesitate to assert that it must be regarded as
a new species.

Structure of the Proximal End.—The sicula is slender and very
long. It tapers so finely in an upward direction that in many
specimens it is exceedingly hard to say where the sicula ends and
the virgula begins. In some specimens it is certainly } inch long,
but in others it is slightly less ; its apex usually lies on a level with
the 4th theca of the primordial series and half way up the central
part of the 3rd theca of the second series; it was furnished with an
apertural spine.

The sicula is completely visible only when the rhabdosoma is
viewed from the dorsal side. From its base on the left side
arises the ‘primordial bud’ whence the first theca originates. It
grows parallel with the sicula for a short distance, and then
describes a gentle concave curve outwards. It never exceeds
zs inch in length, and is commonly rather less. The sicula is
apparently free on the right side for 4 of its length, but when
viewed on the reverse side only the sicula-base and a small portion
of the side are visible, since the rest is concealed by the conuecting-
canal and the initial part of the theca 1”. In its earliest stage this
theca closely follows the outline of the sicula for a short distance.
This fact is only seen on the reverse side, so that, viewing the
rhabdosoma from the obverse side, theca 1’ appears to originate
at about 3 way up the sicula, while in reality it has originated
earlier. This theca is also concavely curved, but the curve is less
than that described by theca 1’; and therefore the aperture of
theca 1” rises to a greater height than does that of 1*, though both
are of approximately the same length.

The aperture of theca 1’ is always more than ; inch above
the base of the sicula.’ It rises to a level of 4, inch from the
sicula-base, and is at a distance of ;4, inch from it.

Character of Mature Rhabdosoma.—The rhabdosoma is always
small; it is commonly 1 inch long, but a few specimens have
been found in which this dimension is slightly exceeded. It is

1 Tn all forms of P. palmeus (Barr.), the first thecal aperture is always less
than 1, inch from the base of the sicula,

Q.J.G.S. No. 210, P

202 MISS G. L, ELLES ON THE SUBGENERA [May 1897,

concavo-convex, with great convexity on the reverse side. Mature
forms are oblong, and have a rounded, narrow distal end. The
maximum width is attained very gradually ; it is never reached till
half way up the rhabdosoma, that is, 3 inch from the proximal end.
It never exceeds 3 inch, but is usually about that measurement.

In the longer forms the rhabdosoma remains at the maximum
width for a very short distance, but more commonly begins at once
to diminish again. In some specimens, as a result of the extreme
convexity, the distal end of the reverse aspect is seen to have a
pointed appearance, but this is not usually the case.

The thece are alternate; they are ;4, inch long and 43 times as
long as wide; their apertures are very slightly concave, and are
perpendicular to the long axis of thetheca. There are 36 apertures.
in the space of an inch. There is not much difference in the width
at the aperture and the width at the initial part. Growth-lines
parallel to the aperture are often seen. The thece are inclined to
a median line at a constant angle of about 45°. The amount of
curvature decreases towards the distal end. On the obverse side
there are indications of the presence of aseptum, but on the reverse
side in a specimen preserved in relief there is no trace of one, so
that it must be incomplete.

Tornquist has shown that this is the case. It appears from his
work that the septum extends half way through the rhabdosoma,
but it may be still further reduced.

The virgula is conspicuous, and is often distally prolonged.

MEASUREMENTS OF VARIOUS Forms.

sm na Ree] w. | ie 2t| aon
Rites Vee = 15 ae = 25 ee ee Dobb’s Linn.
Pa asl ees 1z 14 neg Wear: = 3 & » ”
ee cae ne 20 Tz vee s 8 %9 9
14...) +4 as i9 |+7, |-3 L 4 Skelgill.

1G a +: 21 ? —1 q +2 Dobb’s Linn.
23 i Ts 18 ee ery S +5 ” ”
25 zi Tz 19 1) Vas 3 $ ¥9 ”
29 2 eo ee ala aes i) $ Skelgill.
Aes es a 19 =e x i Tommarp.

I have also taken measurements of a number of species of all
ages, and the following table shows the relation between the
number of thece and the length :—

Vol. 53.] PETALOGRAPTUS AND CEPHALOGRAPIUS. 203

No. | No. of thece. Length. Locality.
26. 5 x Dobb’s Linn, Moffat.
| 12. r¢ —+t “i “a a
| 2. 8 —4 <t 35 +
113 10 & adie ee ee
8 11 2 * 4 “5
21, 12 $ - i, i
18. 13 £ a “
as 14 is 09 %» 9
7 14 15 ” » 99
1 15 Ys - 9 ”
11 15 ¥s 25 ” »
3 16 1s ” ” ”
9 16 +3; £ is 25
| 10 16 sey % ” ”
| 29. 18 i Skelgill.
23. 18 + Dobb’s Linn, Moffat.
14. 19 aoe Skelgill.
A. 19 a Tommarp, Skane.
ive 20 tr Dobb’s Linn, Moffat.
42, 20 zl Skelgill.
16. 21 3 %9

General Characters——This species has sometimes a superficial
resemblance to young forms of P. palmeus (Barr. restr.), and P.
palmeus, var. latus (Barr.), but can be readily distinguished from
them. ;

(1) The sicula is longer, and attains*a greater height in the
thecal series than in any varieties of P. palmeus (Barr.).

(2) The proximal end is more protracted than in those varieties.

(3) The maximum width is attained later than in either P.
palmeus (restr.), or P. palmeus, var. latus (Barr.). In this
species it is never attained till half way up the rhabdosoma,
while in all forms of P. palmeus (Barr.) it is attained at
once.

(4) There is no trace of a septum on the reverse side. In P.
palmeus (restr.) and in var. latus (Barr.) a continuous
septum is present.

(5) In this species the distal end is gently rounded off, and the
rhabdosoma decreases in width distally. In the forms of
P. palmeus (Barr.) the rhabdosoma retains its maximum
width quite up to the distal end, which is usually abruptly
truncate.

P2

204 MISS G. L. ELLES ON THE SUBGENERA [May 1897,

Horizon.—This species seems to be confined to the zone of
Monograptus gregarius (Lapw.). It is most abundant at the
horizon corresponding to Marr and Nicholson’s zone of Monograptus
jfimbriatus (Nich.), in the Lake District.

It occurs at the same horizon in the Rastrites-Shales of Sweden at
Tommarp and Kongslena; and I have also seen specimens from the
‘colonie Haidinger ’ and Berown in Bohemia, and from the Rastrites-
Beds of Bohmsdorf in Thuringia.

British Localities—Moffat District: Dobb’s Linn (Long Cliff),
Garple Linn., etc. Lake District: Skelgill. ; :

Subgenus Cephalograptus.
CepHALocRaptus cometa (Gein.). (Pl. XIII. figs. 10-16.)

1852. Diplograpsus cometa, Geinitz, ‘ Die Graptolithen,’ p. 26, pl. 1. fig. 28.

1853. Diplograpsus cometa, Richter, Zeitschr. d. deutsch. geol. Gesellsch. vol. v.
‘p. 457, pl. xii. figs. 16-17.

1867. Diplograpsus tubulariformis, Nicholson, Geol. Mag. p. 109, pl. A fig. 15.

1868. Diplograpsus cometa, Carruthers, Geol. Mag. p. 131, pl. v

g. 4
1869. Cephalograptus cometa., Hopkinson, Journ. Quek. iMicnsas Club, p. 159,
pl. viii. fig. 14.

1873. Cephalograptus cometa, Lapworth, Geol. Mag. p. 555 & Proc. Geol. Assoc.
vol. ii. p. 167.

1876. pple lcorany cometa, Lapworth, ‘Graptolites of Co. Down,’ p. 182,
pl. vi. fig. 4; ‘Cat. Western Scottish Fossils,’ pl. i. fig. 31.

1878-79. Diplograptus cometa, Tornquist, Geol. Foren. Férhandl. vol. iv. p. 456.

1882. Cephalograptus cometa, "Tullberg, K. Svenska Vet. Akad. Handl. vol. vi.
no. 13, p. 15.

1890. Diplograptus cometa, Geinitz, ‘Graptoliten des k. Mineralog. Mus.
Dresden,’ pl. A. fig

1893. Cephalograptus cometa, Tornquist, ‘Structure of some Diprionide,’ K.
Fysiogr. Sallsk. Handl., Lund, vol. iv. p. 11, figs. 836-41.

The distinctive character of the external form of this species was
recognized by Hopkinson when he founded the subgenus Cephalo-
graptus, in order to separate the form from the ordinary types of
Diplograptus. He did not, however, recognize all its structural
characteristics. It was left to Tornquist to do this in his work on
the ‘Structure of some Diprionide.’ Geinitz’s original description,
and, indeed, all the earlier descriptions, were founded on incomplete
specimens, and the figures given are therefore not characteristic.
In his more recent work Geinitz acknowledges the figures of later
authors ; but I do not think that these either are based upon com-
plete specimens. Tornquist’s are the only figures on which reliance
may be placed. One of his figures certainly shows a complete
specimen, and he alone gives figures showing the characteristic
structure of the proximal end. I have but little to add to Térn-
quist’s work in this respect.

Structure of the Proximal End.—As Tornquist has shown, the
sicula is completely visible in both obverse and reverse positions of
the rhabdosoma. It is short, compared ya the great length
attained by the earliest thece. It is about #4, inch long. When

A ee SS A

es

a a

Vol. 53.] PETALOGRAPTUS AND CEPHALOGRAPTUS, 2095

viewed from the obverse side it is free for the whole of its length
on the right-hand side, recalling strongly the position of the sicula
in all forms of Monograptus.

The first theca of the primordial series arises close to the base of
the sicula and grows slightly downward, so as to be a little below
the base of the sicula; it grows also upward (apparently) simul-
taneously, making a very gentle outward curve.

The first theca of the second series does not develop from theca 1°
till it has grown some considerable way past the sicula. Hence
the reason why the sicula is completely visible in both aspects
of the rhabdosoma. The virgula is seen, as usual, to arise at the
apex of the sicula, and it is worthy of note that at first it runs
along the dorsal side of the first theca for some little distance ;
then, however, it is seen to pass into the centre of the rhabdosoma.
It is very slender in this species, especially at its origin. ‘The
entire proximal end is slender, being much protracted ; the attenua-
tion is especially conspicuous at a short distance from the proximal
end, and it is at this point that the rhabdosoma is so frequently
broken off. When the rhabdosoma is perfect there is seen to be
a slight dilatation at the extreme proximal end where the sicula is
placed.

The whole proximal end would seem to have been flexible, for
the most slender forms are often seen to be somewhat sinuous.

The two earliest thece are both very long and narrow. The
first of the primordial series is ordinarily ;4 inch long, but may be
as much as 4 inch. All the thece subsequently deve-
loped are shorter.

Character of Mature Rhabdosoma.—The whole rhabdosoma, when
mature and complete, seems always to have exceeded 3 inch in
length, and is often nearer 1 inch. Owing, however, to the
extremely rare occurrence of a complete specimen, it usually appears
much less. Specimens from different localities are apt to vary
slightly in width, but never to any very marked extent.

The maximum width of 54, inch is attained opposite the aperture
of the first theca of the primordial series. This width is sometimes
maintained as far as the aperture of the first theca of the second
Series, and then decreases, or a decrease in width may have taken
place before the aperture of the first theca of the second series is
reached.

The thecz are always few in number; I have never seen a
specimen in which there were more than 6 on each side. The
apertures are all within a small fraction of the distal extremity,
forming a kind of crown; they are arranged alternately. The
thecee are very long and tubular. They are usually rather less than
5 inch long and are 12 times as long as wide. ‘The thecal aper-
tures are perpendicular to the long axes of the thece, and often
nearly perpendicular to the long axis of the rhabdosoma itself.
Growth-lines are often beautifully seen in specimens preserved in
relief. The angle at which the thece are inclined is very steep;

206 MISS G, L. ELLES ON THE SUBGENERA [May 1897,

it varies from 5° to 10°. The thece are but very slightly curved ;
those at the distal end are short and straight.

As Tornquist has shown, the septum is invisible on the reverse
side of the rhabdosoma; in fact it is so reduced that it can scarcely
be said to be more than a mere fold of the periderm on the obverse
side. The median fold is not continued to the proximal end of the
rhabdosoma.

The virgula is distally prolonged, and not infrequently split at
some point along its length.

No.) ese aia pak Sil web ie oles Toca
1s, | 42 ve | tH, hs ... | 6+5 | Hartfell.
2. te?! xe ue a gr | 5+4 | Belcraig.
3. Ie ve Tz Tz 1 vee ”
4, g cies a Was ase ... | Browgill.
6 Tz vs |—zs | 4+38 | Tommarp, Skane.
7. % 1s Ts rei) | aaane 4+3 ” ”
ld. 31 | —2 7 os vse | 5+4 | Kongslena, V. G.
12%. 3 Te Tz Tz Te d+4 ” ” 9
12», 2 or ot .. | 4+8 9 ary)
UA ge a as Tz re | O+4 08
13°. 8 z Tz Tz ? 4+3 3 9
14. ies die ts a ne 4+4 5 ih Bh
15 Tz z vs 1s vs | 4+3 2 99

Horizon.—This species has long been recognized as belonging to
a distinct horizon at the base of the zone of M. spinigerus (Nich.),
both in this country and on the Continent.

British Localities—Lake District: Browgill. Moffat District :
Dobb’s Linn, Belcraig. Ireland: Coalpit Bay.

CEPHALOGRAPTUS PETALUM, sp. nov. (Pl. XIII. figs. 6-9.)
= Diplograpsus tubulariformis, Nich., Geol. Mag. 1867, pl. vii. figs. 12 & 18.

In 1867 Prof. Nicholson described a form to which he gave the
name Diplograptus tubulariformis. Subsequent authors have taken
this name as a synonym for (. cometa (Gein.), and the description
given by Nicholson certainly corresponds closely with that species.
Having examined the specimens, which I believe to be those figured
by him as D. tubulariformis, | am convinced that they belong to
three distinct species. The specimens from which figs. 12 & 13
(op. supra cit.) were drawn belong to aspecies hitherto undescribed ;
fig. 14 is that of a young form of Petalograptus foliwm (His.); and
fig. 15 is probably meant to represent the true Cephalograptus

Vol. 53.] PETALOGRAPTUS AND CEPHALOGRAPTUS. 207

cometa (Gein.). Under such circumstances it seems best to adopt a
new name for the species represented by figs. 12 & 13, specimens
of which I have also procured for myself from Dobb’s Linn and
Belcraig Burn. The species in question is undeniably a link
between the Petalograpti and the Cephalograpti, as represented
on the one hand by Petalograptus foliwm (His.), and on the other
by Cephalograptus cometa (Gein.).

Speaking generally, we might say that this species is distally a
Petalograptus and proximally a Cephalograptus, since the characters
of the thecze show that it is closely related to P. foliwm (His.), but
the character of the proximal end proclaims it a true Cephalc-
graptus.

Structure of the Proximal End.—The position of the sicula
again strongly recalls the Monograptus-type. It is entirely free on
one side in either aspect of the rhabdosoma. It is furnished with
an apertural spine. The whole proximal end is slender and pro-
tracted as in C. cometa (Gein.), but it is not so long as in that
species. The first theca of the primordial series appears to arise
slightly above the base of the sicula; it describes a decided outward
curve, and attains a length of 3 inch.

The first theca of the second series arises from 1' just after the
first of the primordial series has grown past the sicula.

The proximal end is straight, as in P. folawm (His.), not sinuous
as in C. cometa (Gein.).

Character of Mature Rhabdosoma.—The forms of the mature
rhabdosoma are very varied. Some approach more nearly to
P. folium (His.), others are more like C. cometa (Gein.). The
greatest length attained by any specimen that I have seen was
1 inch ; this is exceptionally long: the specimens are more commonly
about 3 inch in length.

The maximum width of + inch is not attained opposite tho
aperture of the first theca, but the rhabdosoma gradually increases
in width as far as the third theca of either series ; a constant width
is then maintained up to the distal end.

The thece are alternate; they are tubular; the earliest ones are
3 inch long, but those in the middle of the rhabdosoma have a
constant length of 1 inch; there is a further diminution in length
at the distal extremity. The thece on an average are 8 times as
long as they are wide. The apertures of the earliest thece are
oblique to the general direction of the rhabdosoma, but near the
distal end they become more nearly perpendicular ; they are always
perpendicular to the long axis of the theca. The apertures of the
earliest thecze overlap 4, but this decreases distally.

There are 2+ apertures in the space of an inch, and they are not
all near the distal end as in C. cometa, but the rhabdosoma has
apertures for fully half its length on either side. The angle of
inclination is about 10° in the middle of the rhabdosoma, but it is
less proximally and distally. The thece are almost straight.

208 _ MISS G. L, ELLES ON THE SUBGENERA [May 18097,
There are no indications of the presence of a septum. The

virgula is, as a rule, prolonged beyond the distal extremity. Its
course is similar to that described in the case of C. cometa (Gein.).

TABLE oF MEASUREMENTS.

L. 0 W. opp. No. of Localities
Spee oie | gin. soe he + i cups thece.| (Moffat District).
IP SS2 ca ae vs 4 ts 3 14 | Frenchland Burn.
Psion ee ae 4 +s t 17 | Duffkinnell Burn.
Da eae oe zs a _ x 30? | Dobb’s Linn.
DD pies tiees bee ts =. 3 ty 9 | Duffkinnell Burn.

Horizon.—The specimens obtained from Dobb’s Linn and Belcraig
Burn were found just below the zone of C. cometa (Gein.), but the
species probably ranges up into the latter zone.

British Localities.—All the specimens known to me were found
in the Moffat district ; they come from Dobb’s Linn, Belcraig Burn,
Frenchland Burn, and the Duffkinnell Burn near Wamphray.

TABLE sHOWING Ratio or THECAL TABLE SHOWING RATIO BETWEEN
LrnetH AND BREADTH IN THE TuHeEcat Leneth anp LenetH
VARIOUS SPECIES. OF SICULA.
Species. Ratio. Species, Ratio.
P. palmeus, var. tenwis......... Ze i. P. palmeus, var. tenuis...) 2:1
AP OMIRUUSS ches santas dotenenerees au 1 PB. WANOT ” dnc ccdeee eee 2 al
P. p. var. ovato-elongatus (a).| 34 : 1 P, POlMCUS —oneaen eee 12%
% " (OE orl ie Se | P. p. var. ovato-elongatus| 1: 1
P. palmeus, var. latus ......... Ao DP. pu var. (ats, eae heed
WP OUGUUS! ln.th race vert sn er Reaes 4:1] P 2 OUCtUS Jue, ee 2 I
UILENOT Sacha caus ons ese ee: Ars | P, folitia sn. doen 4:]
IMATE EE oe oy eel C. petalum ...s:4geee ee
CEPCOM WHE Macbian dasa cintebweacaee Shall C. COMECLE: ase Syl
CS COME LG are aeceolars eee Zed

Wol.5 3.1 PETALOGRAPTUS AND CEPHALOGRAPTUS, 209

ITV. General ConcLusions.

From the descriptions that have been given, there can, I think, be
no doubt that the forms referable to the subgenera Petalograptus
and Cephalograptus differ from those more common forms of Dzplo-
graptus, included in Lapworth’s subgenera Orthograptus and
Giyptograptus, which we are accustomed to regard as typical of the
genus. The structure of the proximal end of such forms has been
described in detail by Dr. Wiman (‘ Ueber Diplograptide ’).

Orthograptus foliaceus (Murch.) and Orthograptus truncatus
(Lapw.) fall into such a class, and the external resemblance of
these species to some of the Petalograpti is evident at a glance.
In these forms the proximal end is not protracted, and the sicula is
not completely visible in either aspect of the rhabdosoma, but the
characters of the thece are strikingly similar to those of Petalo-
graptus palmeus (restr.). I regard this as significant ; the differences
separating the forms can so easily be brought about by very slight
alteration in the mode of development that I cannot refrain from
offering the suggestion that the Petalograpti have been derived
from Orthograptus foliaceus, and that Orthograptus truncatus is
merely a step on the way.

In O. truncatus (Lapw.) the canal connecting 1’ with 1° is
almost horizontal, so that the theca 1° arises at nearly the same
level as 1.1 If the connecting-canal became more oblique, and the
thecee more concayely curved, a form identical with P. palmeus
(restr.) would be the result. If the theca 1° arises still later, and
the thece at first grow parallel with the sicula and then curve, the
resulting form is identical with Petalograptus minor (sp. nov.).
The thecze in this form are longer.

A further increase in thecal length would give the form P. folium
(His.). Now we have reached an important stage. Should the
theca 1° develop so late from the first that the first has already
grown past the apex of the sicula, the sicula will be entirely
free on the side remote from that on which the first theca of the
primordial series arises. Such a form we have in Cephalograptus
petalum, other changes being a diminution in the angle of incli-
nation and further increase in thecal length. The extreme type is
reached in Cephalograptus cometa, in which the theca 1” arises still
later, the thece are still longer, and are almost parallel to the long
axis of the rhabdosoma. The other forms of Petalograptus may be
derived from P. palmeus by slight alterations in the amount of
curvature.

That the Petalograpti have a Phyllograptus as a remote ancestor
seems very likely, but the evidence for this is at present incomplete.
Neither am I able to state whether the C. cometa (Gein.) type has
a further stage in a form of Dimorphograptus or not. I know no
Dimorphograptus which resembles it, and it seems possible that,
owing to the excessively fragile nature of the proximal end, this
form was not that most fitted to survive in the struggle for life.

210 _MISS G@, L, ELLES ON THE SUBGENERA [May 1897,

SuecEsreED PHYLOGENY.

4
?
5

Orthograptus truncatus (Lapw.).

Petalograptus palmeus (Barr.).

| [(Kurck).

P. minor, sp. nov. P.p. var. ovato-elongatus

? ?
| aay | [(Barr.).
P. folium (His.). P. palieus var. latus

P. palmeus, var. tenuis. |
C. petalum, sp. nov. P. ovatus (Barr.). i

C. cometa (Gein.).

In conclusion I offer my grateful thanks to Prof.T. McK. Hughes,
F.R.S., for much kind encouragement; to Prof. Lapworth, F.R.S.,
and Mr. J. E. Marr, F.R.S., for kind help and advice, and for the
loan of specimens ; and to Prof. Otto Torell, Director of the Swedish
Geological Survey, Dr. G. Holm, and Dr. Tornquist for facilitating
my work in every way during my stay in Sweden:

EXPLANATION OF PLATES XIII. & XIV.

All the figures are X 2. Those marked * are in the
British Museum (Nat, History).

Puate XIII,

Figs. 1-5. Petalograptus folium (His.).

Fig. 1. Reverse aspect of mature specimen, showing the base of the sicula on.
the left. Belcraig.

2. Obverse aspect, in relief, of mature specimen, showing the position

of the sicula and the character of the proximal end. ‘Thecal striz

well seen. Kallholn.
3. The same, in relief. Kallholn.
4, Reverse aspect of the proximal end, showing the base of the sicula
with the apertural spine. Kallholn.

*5, Obverse aspect of a young specimen.
Duffkinnell Burn, near Wamphray.

Figs. 6-9. Cephalograptus petalum, sp. nov.

Fig. *6. Obverse aspect of foliate form, showing the position of the sicula and
the course of the virgula. Duffkinnell Burn.

*7, Reverse aspect of a young specimen incomplete at the proximal end,
showing only the apex of the sicula. Duffkinnell Burn.

*8. Reverse aspect, showing the splitting of the virgula outside the
rhabdosoma. Frenchland Burn.

9. Reverse aspect of a very long specimen. Dobb's Linn.

Yok: 5 3.] PETALOGRAPTUS AND CEPHALOGRAPTUS. 211

Fig. *10.
11.

12.
13.
14,

15.
16.

Me, *1.

¥4,

Bige= *5.

Fig. 9.
10.

Fig. *15.

*16

Figs. 10-16. Cephalograptus cometa (Gein.).

Obverse aspect of an incomplete specimen. Duffkinnell Burn.
Obverse aspect of a curved specimen ; proximal end wanting.
Beleraig Burn.

Obverse aspect of a complete specimen, showing the position of the
sicula. Kongslena.
Distal end, preserved in relief, showing characteristic thecal
striations. Tommarp.
Reverse aspect of proximal end, showing position of the sicula and
course of the virgula. Preserved in relief. Tommarp.
Obverse aspect of proximal end; preserved in relief. Tommarp.
Obverse aspect of proximal end of a curved specimen ; preserved in
relief. Tommarp.
PuaTe XIV.

Figs. 1-4. Petalograptus palmeus, sensu stricto (Barr.).

Reverse aspect of a mature specimen, showing the sicula with the
apertural spine. Owing to the mode of preservation, the sicula is
seen through from the obverse side. Zelkovice.

. Obverse aspect of mature specimen, showing the sicula and the

general characters of the proximal end. Conway.

. Obverse aspect, showing the splitting of the virgula within the

rhabdosoma. Dobb’s Linn.
Obverse aspect of wide specimen. Zelkovice.

Figs. 5-8. P. palmeus, var. latus (Barr.).

Obverse aspect, showing the characters of the proximal end.
Frenchland Burn.

. Reverse aspect of a young specimen ; base of sicula seen on the left.

Dobb’s Linn.

. Obverse aspect of mature specimen, showing the sicula with the

apertural spine. Preserved in half relief. Tommarp.

. Transverse section through the middle of a mature specimen, showing

the septum and the position of the virgula. Specimen preserved
in iron pyrites. Skelgill.

Figs. 9,10. P. palmeus, var. tenuzs (Barr.).

Obverse aspect of mature specimen, showing the sicula with the
apertural spine. Skelgill.
Obverse aspect, in relief, of a young specimen, showing the sicula,
the general characters of the proximal end, and the growth-lines
on the thece. Dobb's Linn.

Figs. 11-14. P. palmeus, var. ovato-elongatus (Kurck).

. Reverse aspect of a mature specimen, with the apertural spine. The

cells on the right side have been affected by pressure.
Dobb’s Linn.

. Obverse aspect, in relief, of a young specimen not complete. Skelgill.
. Obverse aspect, in relief, of a mature specimen. Skelgill.
. Transverse section of a specimen, preserved in relief, showing the

continuous septum and the position of the virgula. Skelgill.

Figs. 15, 16. Petalograptus ovatus (Barr.).

Reverse aspect, showing the sicula through from the obverse side;
typical form showing alteration in the angle of inclination.

Zelkovice.

. Reverse aspect of a more oval form, showing alteration in the angle

of inclination. Zelkovice.

212 PETALOGRAPTUS AND CEPHALOGRAPTUS. [May 1897,

Figs. 17-21. Petalograptus minor, sp. nov.
Fig. 17. Obverse aspect of a typical form, showing the long sicula and the

general characters of the proximal end. Dobb’s Linn,
18. Obverse aspect of a mature specimen ; the thecz on the right side are
not perfectly preserved. Tommarp.
19. Reverse aspect, in relief, of a typical form. Note the absence of the
septum, Skelgill.

20. Specimen preserved so as to show some internal structure. Note the
long sicula and the origin of the lowest theca on the right.

Dobb’s Linn.

21. Reverse aspect of a young specimen. The sicula is seen through

from the obverse side. Dobb’s Linn,
Discvssi0n.

Mr. Horxtnson said that this paper was of much interest, and he
considered it to be an important contribution to the history of the
small section of the Diplograptide of which it treated. The details
of the structure had been well worked out, evidently from better
specimens than he had had an opportunity of examining. He
agreed with the Author as to the derivation of Cephalograptus
from Orthograptus through Petalograptus ; but he thought that she
did not attach sufficient importance to the absence of a longitudinal
septum in Cephalograptus, which was one of the main points upon
which he relied in founding the genus. There appeared to be such
a septum in all other Diplograptide, and on this account Cephalo-
graptus was farther removed from Petalograptus than was that
subgenus from Orthograptus. In some cases there could be no
doubt about the phylogeny of the Graptolites. For instance,
Dicranograptus was evidently derived from Climacograptus by the
distal portion of the hydrosoma dividing into two branches, and the
hydrothecee becoming slightly modified; while Dicelloyraptus was
derived from Dicranograptus.by the further division of the hydro-
soma into two entirely separate branches, and the further modifi-
cation of the hydrothece in the same direction (from an angular to
a rounded outline) resulting in a two-branched graptolite which has
no relation to Didymograptus. The Author’s final suggestions had
no such clear foundations as this; and he did not think it at all
likely that Petalograptus was derived from Phyllograptus, nor
could he see how Cephalograptus could be the ancestor of
Dimorphograptus.

Mr. Marr bore testimony to the scrupulous care with which the
Author had conducted her researches. He was not interested
in the separation of Cephalograptus from Petalograptus, for he
believed that most of these terms were temporary in the case
of the Graptolites; but he felt that the Author, by her careful
examination of the whole structure of one group of the Diplo-
graptide, had given geologists a detailed study in phylogeny of
great importance.

CuariJourn- GeolSoe Vol. LM) Pl X iil.

sh

Edwin Wilson,Cambridge.

PoMALOCRAPIUS £ CEPHALOGRAPTUS.

GuertWourn- Geol Soe Vol TAM PL xy

Edwin Wilson,Cambridge.

PE RACOGR AG TUS.

Vol. 53.] BOULDERS FROM THE BETCHWORTH CHALK. 213

15. On two Bovtpers of Granite from the Mippie CHarx of
Betcuwortu, Surrey. By W. P. D. Sreszine, Esq., F.G.S.
(Read February 24th, 1897.)

[Puate XV.]

Bouxpers of various Paleozoic rocks, other than mere pebbles, in
the Upper Cretaceous and in some other strata have at different
times been described, but they are acknowledged to be of com-
paratively rare occurrence in rocks of Mesozoic age. It may be of
interest to summarize briefly the chief finds of this kind which
have been made up to the present in this country.

In 1827 Mantell* observed that ‘In this country the Chalk
very rarely contains traces of older deposits: the only instances
of extraneous rocks that have come under my observation are
pebbles of quartz and some fragments of green schist.’

In 1850 Dixon? wrote :—‘ Small pebbles and large rolled frag-
ments of sandstone and quartz-rock are occasionally discovered in
the centre of the Upper Chalk. Mr. Coombe found one specimen,
weighing near 14 lbs., at Houghton, Sussex, and I have seen others
from the same pit of 2 or 3 lbs. weight. Several also have been
sent me by Mr. Catt from the pits near Lewes.’

In 1857 the well-known Purley boulder was found, of which
this Society is fortunate enough to possess the principal remains.
R. A. C. Godwin-Austen in vol. xiv. of the Quarterly Journal, p. 253,
says ‘the boulder ..... was found in a chalk-pit by the side of the
old London and Brighton road, near Purley..... The portion of
the Chalk-formation in which the pit is worked is the lower part
of that containing flints.’ After the boulder was removed there
were found associated with it a mass of fine, waterworn, siliceous
beach-sand, evidently derived from the waste of a coast-line of
crystalline rocks; a quantity of coarse sand-like material, which on
examination proved to be decomposed rock of the same kind as the
boulder; and a collection of blocks of smaller dimensions, also
waterworn. Most of these were composed of a peculiar and very
different rock, consisting of augite, with lath-shaped, twinned
crystals of felspar; but some were of greenstone. The largest of
them must have weighed as much as 20 to 25 lbs,; all were very
much decomposed.

The form of the boulder itself, which had been broken up by the
workmen, seems to have been roughly egg-shaped, and it was
evidently a rounded waterworn block of crystalline granitoid rock.
The colour is red, and the weight of the fragment in the Geological
Society’s Museum is about 45 lbs.

In 1860 Godwin-Austen recorded the occurrence ® of a mass of

1 «The Geology of the South-East of England,’ p. 78.
2 « Geology of Sussex,’ p. 69.
> Quart. Journ. Geol. Soc. vol. xvi. p. 326.

214 MR. W. P. D. STEBBING ON TWO BOULDERS OF [May 1897,

bituminous coal, with veins of ferruginous clay, in the Upper Chalk
of Kent. This mass, which weighed about 4 cwt., and was from
4 to 10 inches thick and about 4 feet square, was discovered at a
depth of 180 feet in the process of tunnelling for the L. C. and
D. Railway, between Lydden Hill and Shepherdswell, a few miles
from Dover. It was probably of Oolitic or Wealden age.

Messrs. Jukes-Browne and W. Hill mention! that they were
informed, by a man working in a Totternhoe Stone pit at Isleham,
of the find of a number of large stones mixed with material that
looked like rotten wood, in a cavity in undisturbed Chalk.

I noticed last September in the Brighton Museum a block of
quartzite, weighing 13 lbs. 14 oz., from the Middle Chalk of
Houghton, Sussex. It was exhibited by Mr. Henry Willett when
Godwin-Austen read his paper on the Purley boulder before this
Society. It has the lower valve of a Spondylus, a Polyzoan, a
Serpula, and the remains of several other bodies still adhering to
it. The same museum contains also a pebble of clay-slate, weighing
about 1 lb., found in the Lower Chalk at North Stoke.

The Museum of Practical Geology, Jermyn Street, possesses a
large oyoid quartzite-boulder from West Thurrock, discovered 30 feet
below the surface, and two of quartzite and greenstone from Gayton,
Norfolk.

Many fragments of foreign rocks have been found at yarious
times in the Cambridge Greensand.2” In 1872° Messrs. W. J.
Sollas and A. J. Jukes-Browne described several different examples
from their own collections and the Woodwardian Museum,
Cambridge. These were of various shapes, nearly all being sub-
angular, with only one or two rounded specimens. They ranged in
size from 1 cubic foot downwards, some being very much decom-
posed. Others were scratched as if by ice, while almost all were
encrusted with Ostree and Plicatule. The following rocks, among
others, were represented: coarse yellowish grit, purplish-red slate,
grey and reddish sandstones, a fine conglomerate, Magnesian, black
and brown siliceous limestones, granites, black basalt, green mica-
schist, greenstone, obsidian, and labradorite-rock, also joints of
Poteriocrinus and fossil resin. One of the granites, marked 12 in
their paper, much decomposed, consisted of felspar, black mica,
masses of fibrous hornblende, and irregular crystals of quartz.

It should also be mentioned that a large boulder of spherulitic
rhyolite, much rounded and worn, with attached Plicatule, was
found in the Cambridge Greensand at Ashwell, Herts, and is
described by Prof. Bonney in Proc. Camb. Phil. Soc. vol. v. p. 65.4

1 Quart. Journ. Geol. Soc. vol. xliii, (1887) p. 554.

2 T. G. Bonney, Proc. Geol. Assoc. vol. iii. p. 1.

3 Quart. Journ. Geol. Soe. vol. xxix. (1873) p. 11.

4 Among examples of boulders in rocks composed of fine sedimentary or
organic material may be mentioned the following :—Quartzite, granitoid and
other rocks in the Coal Measures, EH. W. Binney, Mem. Lit. & Phil. Soc. Manch.
1851, vol. ix. ser. 2, p. 8306; T. G. Bonney, Geol. Mag. 1873, p. 289, and Rep.
Brit. Assoc. (Birmingham), 1886, Pres. Addr. Sect. C, p. 601; J. Radcliffe,
Quart. Journ. Geol. Soc. vol. xliii, (1887) p. 599; J. Spencer, zbid. p. 734;

Vol. 53.] GRANITE FROM THE MIDDLE CHALK OF BETCHWORTH. 215

We turn now to the main subject of this communication—the
boulders obtained by me at Betchworth.

According to a tradition which I have been unable to authenticate,
Betchworth chalk-pit, which is about 4 miles from Dorking, was
worked in the time of the Romans. Whether this be true or not,
there is no doubt that quarrying has been in operation there for a
very long period. The section exposed in the pit extends from very
near the base of the Chalk to the top of the zone of Terebratulina
gracilis. The two blocks (A and B) which form the subject of
this communication were obtained last April from one of a gang of
men working on the western side of the pit, and engaged in clearing
away the chalk above the zone of Holaster subglobosus. They came
from the zone of Terebratulina gracilis, and were found after a
blast. Unfortunately both of them are broken. It is likely, as
they are very much decomposed, that they were broken through
their fall after the blast, or by the blast itself: the boulders may, of
course, have been broken by the men themselves before they were
observed; but the workmen assured me that they saw no other
fragments.

The weight of the larger boulder (A) was 7 lbs. 7 oz. when
it first came into my hands. In shape it is roughly quadran-
gular, measuring 5°8 x 6°25 x 4:125 inches. It is a fine-grained
granite, so very much decomposed that it will hardly bear handling,
and is rotten enough to be rubbed away by the finger. It has the
remains of several lower valves of Spondylus latus and some
Serpule still attached. On the broken side it is stained with
streaks and spots of iron oxide. There are also parallel to that side
one or two small cracks.

The other fragment (B), which seems to be the half of a roughly
ovoid mass, weighed 3 lbs. 12 oz., and measured 3°6x5:8x
4-5 inches. This also isa granite; but it is interesting to observe
that it is of altogether different character from the other, there
being large irregular crystals of quartz visible on part of the
exterior, while on the broken surface mica is very distinct in places.
It is not nearly so much decomposed as the other specimen.

I am indebted to Prof. Bonney’s kindness for the following notes
on the microscopic structure of the rocks :—
‘ Boulder A.—Structure granular, with some irregularity in size

and an occasional slight tendency to clustering of grains which are

alike in size or nature: seldom any approach to idiomorphism.
Constituents: quartz (not very abundant), sometimes with slight
strain-shadowing, occasional microlithic inclusions, and very minute
cavities. Felspar: ordinary plagioclase, microcline, and probably
orthoclase: often embedding small grains of quartz; also some

M. Stirrup, Rep. Brit. Assoc. (Manchester) 1887, p. 686, and Trans. Manch.
Geol. Soc, vol. xxi. 1891, p. 172, etc.; and angular fragments of granite,
quartzite, etc.,in the Carboniferous Limestone, V. Ball, Quart. Journ. Geol. Soe.
vol. xliv. (1888) p. 871. To the ice-borne masses of rock of the Glacial Beds it
is needless to refer.

216 MR. W. P. D. STEBBING ON TWO BOULDERS OF [May 1897,

grains of a mineral having a very slight earth-brown tint in
ordinary light, and appearing (with crossed nicols) as an aggregate
of minute specks inclining to flaky or fibrous, which have weak
depolarizing power: probably a pinite (? after cordierite). A very
little of rather altered biotite and iron oxide, also zircon, and (?)
rutile, both small and rare. The structure of the rock is not that
of a normal granite, but more nearly resembles one of those which
are often banded, and commonly occur in a complex of the older
Archean, such as the so-called Laurentian or Hebridean (see fig. 1).

‘ Boulder B.—The constituents in this specimen differ, in that much
of the felspar is ordinary plagioclase, and orthoclase is more certainly
present: the pinitic mineral is doubtfully present; there is very

Fig. 1.—Microscopie section of Boulder A.

ey

x 380.

The dark grain at the edge. about 8.8.W. of the centre, is blackened biotite,
and there are some small films to the N.W. of it. The lighter grains are
quartz ; the rest is felspar. A trace of minute micrographic structure is
visible. The rock is cracked, but the peculiarly formed clear space
between S.E. and E.S.E. is caused by a breakage in the slice.

little biotite, but much white mica. A little of this may be
bleached biotite, and in one or two cases I think that small flakes
of biotite are interlaminated. There is a small elongated cluster
of impure red garnets, pierced longitudinally by a thin tongue of
quartz (see fig. 2). In this rock signs of mechanical action are
clear. The mica is sometimes bent or ‘rucked,’ the quartz and

ae
—-

Vol. 53.] GRANITE FROM THE MIDDLE CHALK OF BETCHWoRTH. 217

felspar are more or less cracked and recemented; there are some
strain-shadows in the former, and I am disposed to attribute a
cross-hatched structure, which occurs ‘ sporadically’ in the latter,
to the same cause. The rock, in short, is gneissoid from pressure,
and resembles those which are rather common in the same regions
as the last-named.

‘T have compared these slices with one from the original Purley
boulder given to me by Prof. Judd. In this the felspar is more
distinctly idiomorphic, the quartz has slightly larger cavities, there
is hardly any mica (biotite), and one small grain, I think, of horn-
blende. One or two zircons occur, and also a few very small

Fig. 2.— Microscopie section of Boulder B.

The dark grains are garnets containing much opacite. The clear grains are
uartz. The white mica can be recognized by its cleavage-lines. The
rest of the slide is felspar. The rather wavy dusty lines are cracks, stained

or bordered with decomposition-products.

minerals, probably of secondary origin, together with one slightly
larger, which is oblong in form; these I cannot identity with
certainty, and need not discuss on the present occasion. This rock,
though less affected by pressure, might have come from the same
region as the others. I have also compared Mr. Stebbing’s
specimens with a slice from a boulder obtained by Mr. Starkie
Gardner from the Kentish Gault, which is almost wholly composed
of quartz and felspar, and is much pressure-modified.’

ecb GS. No. 210. Q

218 MR. W. P. D, STEBBING ON TWO BOULDERS OF [May 1897,

The existence of these extraneous fragments suggests some
interesting questions. We should like to know from what special
localities, and by what controlling agencies, such foreign substances
came into their present positions, though I have no doubt that over
and beyond these a multitude of other questions might be raised.

With respect to the various theories that have been mentioned,
so far as I may venture to offer an opinion, the agency of berg-ice
does not appear likely to have come into play in the movement of
boulders such as those from Betchworth.

Coast-ice appears to have been the probable medium of con-
veyance. The same explanation is applicable to such a case as that
of the Purley boulder, where there was a mass of stones of various
sizes with beach-sand, and also to the Cambridge specimens. Some .
of the latter have scratches on them, which in a few cases are
covered by Plicatule affixed after they were made. The scratches
were very likely caused by the grinding up and down of the ice
holding them on the shore before it floated off. Shore-ice has
occurred on the East coast of England, and is known to have
carried away shingle frozen into it. Specimens in this case need
not be much rolled, as fresh material is nearly always being added
from the foreshore and cliffs.

Another very probable agency would be the entanglement of earth
and stones in the roots of trees. The mass of stones mingled with
what looked like rotten wood, noticed by a workman in a Totternhoe
Stone pit at Isleham, and recorded by Messrs. Jukes-Browne and
W. Hill, would appear to have been so transported. Darwin, in his
‘Journal of the Voyage of the Beagle,’ mentions the occurrence of
a piece of greenstone on a coral-island in the Indian Ocean, which
clearly could not have been brought there by any other agency.
Analogous to that manner of conveyance would be the clinging of
seaweed to stones and rock, either below or between tide-marks.

Most of the boulders that I have mentioned would exceed the
weight that could have been so shifted, but not so the granite-
fragments in the Carboniferous Limestone near Dublin, which
Valentine Ball supposed to have been thus distributed. The same
theory would also explain the occurrence of some of the various
small pebbles of quartz, etc., in the Chalk.

It may be thought rather fanciful to add the hypothesis, suggested
by one enquirer, of marine animals as such carriers. At all events,
that would be compatible only with the transport of few and minute

ebbles.’

: The mass of supposed Mesozoic coal found in the Chalk near
Dover may very well have been transported by coast-ice, ‘being
gently deposited when the ice melted.

As for extraneous boulders, they seem to come oliedi font the
Middle Chalk and about the zone of Terebratulina gracilis. ‘To my
knowledge only three specimens of granite have been obtained from
the Chalk, namely the Purley boulder and these two Betchworth

1 For a recent instance of this kind, in which penguins and fur-seals are the
carriers, see the Challenger Reports, Zoology, vol. ii. (1881), Birds, p. 126,

Quart. Journ. Geol. Soc. Vol. LIII. Pl. XV.

THE BETCHWORTH BOULDERS.

[From a Photograph.|

Vol. 53.] GRANITE FROM THE MIDDLE CHALK OF BETCHWORTH. 219

specimens. Granite seems to be rare in the Coal Measures also,
quartzite being by far the commonest rock in both deposits.

One of the Betchworth specimens, the quartzite in the Brighton
Museum, and most of the Cambridge boulders have shells, etc., still
affixed. They are typical Middle Chalk and Cambridge Greensand
forms, and evidently grew there after the boulders were dropped
on the sea-bottom.

A further question of interest in relation to these and other
fragments is the identification of the places whence they set out.
Present evidence seems to point to the north as the starting-point
of most of them; but there is no certainty about the particular
localities. Godwin-Austen supposed the Purley boulder to have
come from Scandinavia, which also appears to be the origin of many
of the Cambridge Greensand fragments, though some at any rate
may be presumed to have originated in Scotland. To the Scottish
Highlands or, in Prof. Bonney’s judgment, more probably to
Scandinavia may be assigned also the birthplace of these two
Betchworth boulders.

PLATE XV.
Reproduction of photographs of the Betchworth boulders, & nat. size.

Discussion.

Prof. Bonny said that these rocks showed the granular structure
often seen in rocks of Laurentian type, contained microcline, white
mica slightly bent up, and, to a certain extent, a mosaic of quartz.
The felspar in the Purley boulder was more idiomorphic. He
thought that the subject had been very clearly and well brought
before the Society.

The PresrpEenr remarked that Mr. Stebbing and Prof. Bonney had
opened out a question of great interest. Few probably were pre-
pared to admit the existence of a glacial period in the heart of the
Cretaceous, but the hypothesis of floating ice came up here. Masses
so transported must have come from a considerable distance ; there
was indeed room for much imagination and much discussion. The
Author had mentioned transport by marine animals, driftwood,
seaweed, and finally ice—which latter appeared to be the most
reasonable.

Mr. Srrawan complimented the Author on his careful record of
the circumstances under which these boulders had been found. It
seemed curious that such foreign bodies were not found more
frequently, considering how vast a number of Chalk-exposures
occurred throughout the country. In other marine formations,
moreover, they are almost unknown—possibly, however, in con-
sequence of the difficulty of detecting them. :

The complete rounding of many of the boulders, and the adhesion
to them of Chalk organisms, pointed to their derivation from a
shore; and this, taken in connexion with the large size of some
of them, made it difficult to understand that they had been floated

a2

220 GRANITE-BOULDERS FROM THE MIDDLE CHALK. [May 1897, ©

out to sea entangled in the roots of trees. On the other hand, the
theory of glacial transport needed confirmatory evidence.

Dr. Hume thought that the presence of these boulders in the
Chalk could not be taken as evidence of the existence of a Cretaceous
glacial period. ‘There is a total absence of the traces of a glacial
current, and the fauna observed points rather to the conclusion
that, if a current existed, it would more probably have come from
the south. The large size of the Purley boulder makes it difficult
to assume the transport by seaweed, trees, and especially fishes, so
that at present the action of ice as an agent cannot be absolutely
dismissed.

Prof. Jupp maintained that the size of the boulders from Croydon
was such that it was impossible to account for their transport by
floating trees or floating seaweeds over great areas of the ocean.
He considered that the larger blocks could only have been carried by
ice—though the paucity of blocks pointed to the conclusion that,
while the Cretaceous sea was occasionally traversed by stray ice-
bergs, there could have been nothing like a glacial period.

Mr. A. E. Satrer thought that the smaller pebbles found in the
Chalk were deserving of attention and study. ‘They were more
numerous and of greater variety than the large boulders, and
might, on careful microscopical examination, yield valuable evidence
as to the source of origin of these erratic bodies. Mr. Dibley had
recently obtained more than a dozen pebbles of various rocks from
the same pit near Croydon as that whence the large, so-called ‘ Purley
boulder’ came. He had also obtained several from Northfleet. A

now disused portion of the great chalk-pit at Burham had yielded .

several some years ago, and Prof. Wiltshire also obtained a large
number from Northfleet which are now in the Woodwardian
Museum.

Mr. Wuirtaker also spoke.

The AvrHor, in reply, explained that he had never supposed
a glacial period to be a condition of the migration of these boulders,
since any winter would have sufficed. On behalf of the hypothesis
of coast-ice which had been criticized, he reminded the Society of
the presence of beach-sand with the Purley boulder. The question
of small pebbles had been left untouched by him as being outside
the sphere of the present paper, which was concerned only with the
larger specimens.

Vol. 53.] IZALCO AND OTHER VOLCANOES IN CENTRAL AMERICA. 221

16. Izauco and ornER VoLcanoEs a Cxrntrat America. By
A. Gostine, Esq., H.M. Minister and Consul-General in
Central America. (Communicated by the Prestpenr. Read
March 10th, 1897.)

[Extract from a letter addressed to H.M. Secretary of State for Foreign Affairs. |

Ir may not be wholly devoid of speculative interest to learn that
the voleano of Izalco, in the Republic of Salvador, which has
been in active eruption for over one hundred years, suddenly ceased
to be so in the early days of December 1896.!

Izalco, rightly named ‘ the Beacon of Central America,’ is one of
the most recent and interesting volcanoes in that part of the world;
and J venture to quote some remarks respecting it which I contri-
buted in January of last year to the North American Review :—

‘ Nowhere on this planet, the island of Java, perhaps, excepted,
are volcanoes so numerous and of such varied and eccentric con-
formation as in Guatemala. The most notable are Agua and Fuego,
respectively 12,310 and 13,976 feet in height. During last century
the former vomited forth volumes of igneous matter, beneath which
lies buried the old Spanish city of Ciudad Vieja. Guatemala la
Antigua, the former capital and seat of government under a Spanish
viceroy, with its hundreds of fine churches and religious establish-
ments, was, upwards of a hundred years ago, totally destroyed by
earthquakes caused by the sudden and terrible activity of Fuego.
Of recent years seismic disturbance has been of such rare occurrence
in Guatemala that houses of two or three stories have replaced the
low and substantial structures of former times, built to withstand
the much-dreaded violence of the teerra mota.

‘In the Republic of Salvador, a volcano of recent formation, named
Izalco, by whose agency the capital, San Salvador, was nearly
destroyed in 1873, serves the useful purpose of a beacon for this
iron-bound coast on the Pacific. Towards the end of last century
the site on which it is situated was a fertile knoll where the Indians
cultivated their corn, and where the frequent destruction of their
crops by fire was attributed to acts of vengeance by neighbouring
tribes, giving rise to many a free fight, in which that deadly weapon
the machete played a prominent part; nor was it until a gradual
upheaval of the soil was observed that it occurred to anyone that
these supposed acts of incendiarism were due to subterrancous
ignition. Izalco has now attained an altitude of some 5000 feet,
and coasting navigators watch its rapid growth from year to year.
Its nocturnal] ebullitions form a spectacle of more imposing grandeur
than the eruptions of Vesuvius; explosions occur every 12 or 15
minutes, day and night, with extraordinary regularity, accompanied
by noises likened to the discharge of heavy artillery, followed by
the escape of volumes of dense smoke and flame, carrying with it
hundreds of tons of rock and lava, which on a dark night presents a
most weird appearance.’

1 [The Author draws attention to the fact that an earthquake-shock was
experienced in England on the 17th of the same month.—Ep. |

22? CHANGES OF LEVEL IN THE BERMUDA ISLANDS. [May 1897,

17. Caanezs of Leven in the Bermupa Istanps. By Prof.
Rate# §. Tarr, of Cornell University. (Communicated by
the Secretary. Read January 6th, 1897.)

[ Abstract. |

Tur Author gives a summary of previous writings bearing upon
the geology of the Bermudas; but his own researches point to
a rather more complicated series of changes than those which have
been inferred by other writers. The formation of the ‘ base-rock’
or ‘ beach-rock ’ occurred at some period which cannot be accurately
ascertained at present, owing to the fragmentary nature of the
included fossils. It may have been formed in Pleistocene or even
late Tertiary times. After its formation it was converted into a
dense limestone and then eroded, probably by subaerial agents, and
finally attacked by the waves at an elevation of at least 15 feet
above present sea-level ; during this stage it was covered by beach-
deposits of pebbles and shells, which were accumulated in a period
so recent that the contained fossils are of the same species as the
organisms living in the neighbouring sea. Then followed an
uplift, during which land-shells lived on the beach-deposits; but
these were soon covered by blown sand—the principal accumulations
of the islands, and the outline of the islands was perfected by the
action of the winds. This was done at an elevation which was at
one time certainly as much as 40 or 50 feet above present sea-
level. The author adduces evidence of a depression since this
accumulation, causing land to disappear and the outline of the area
to become very irregular ; and he proves that these changes cannot
be accounted for solely by erosion, as some have maintained. There
are indications that the land is at present quiescent. It appears,
then, that most of the work of construction of the Bermudas has
been done in recent times.

Discussion.

Dr. J. W. Greeory thought it appropriate for the paper to be
sent to this Society, as one of the earliest fossil-collections from
Bermuda was in the Society’s Museum, and as the geological
structure of the islands had been described in the Society’s Trans-
actions by Capt. Nelson. He had hoped that the age of the basal
rock of Bermuda might have been settled by this paper,.as this
would have precisely limited the short period during which had
occurred the movements described by the Author.

Capt. Srirre said that, having given some attention to the subject
whileat the Bermudas, he had formed the opinion that recent elevation
or depression was not necessary to account for the present condition
of thé islands, Aiolian agency was quite adequate to produce the
present state of things. The blown calcareous sand associated with
recent shells has been consolidated into a very porous limestone,
apparently by pluvial and chemical action.

Vol. 53. THE SUPERFICIAL DEPOSITS OF CUTCH. 223

18. On some Superriciat Deposits in Curcu. By the Rev. J. F.
Brake, M.A., F.G.S. (Read February 3rd, 1897.)

[Abridged.*]

Durine a recent visit to Cutch for the purpose of studying the
Jurassic * rocks there exposed, my attention was naturally attracted
to a number of superficial deposits, which in some cases concealed,
and in others were associated with, the solid rocks beneath. I
cannot pretend to have made an exhaustive study of them, as I have
only examined such parts as may be found in the Jurassic area;
but these have suggested certain theories of their origin, which I
have not seen proposed elsewhere, and as these theories depend on
observations which I do not find recorded, it may at least be hoped
that an account of such observations may throw light on the origin
of the deposits. The matters with which I propose to deal may be
classed under the following heads :—

(1) Subrecent concrete.

(2) The boulder-beds associated with this concrete.
(3) Infratrappean grits.

(4) Laterite.

(5) Alluvium and Ran.

Of all these, except No. 2, there are to be found brief descrip-
tions in Mr. A. B. Wynne’s memoir on the geology of Cutch,* but,
as a rule, that author does not venture on any suggestion as to their
origin, and in no case does he appeal to the particular causes to
which I have been led to refer them.

(1) The Subrecent Concrete.

Under this name Mr. Wynne describes some remarkable deposits
of which he writes as follows:—‘ Very generally distributed over
the hilly country is the subrecent caleareous deposit already alluded
to. The white sandstones of which it consists are sometimes
sufficiently coherent to be used for building, and it is very commonly
burnt for lime all over the province. No fossils have ever been
found in it, but on some slabs from the deposit in Western Cutch
tracks of crustacea or of annelids have been observed. It is not
limited to a uniform level in its various situations, having been met
with in the low ground at the foot of the hills bordering the Runn,
as well as high in their glens. Its aspect is always very much the
same, though its texture is varied, being sometimes conglomeratic or
finely oolitic, and generally it presents some oblique lamination.’ *

1 [By the omission of that portion of the paper in which the quartzite-
reefs and their mode of formation were discussed. |

2 Throughout this memoir I use the word ‘Jurassic’ for all the rocks so
coloured on Mr. Wynne’s map, without prejudging the question as to how many
of them may be, as some certainly are, of Neocomian age.

3 Mem. Geol. Surv. India, vol. ix, pt. i, (1872). 4 Ibid. p. 81.

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Vol. 53.! THE SUPERFICIAL DEPOSITS OF CUTCH. 225

This description, which is the fullest in the memoir, does not in
any way indicate the author’s view of their origin. Indeed he
elsewhere says: ‘The... . subrecent deposits, except in their most
superficial portions, contain no evidence as to the conditions under
which they were accumulated.’

Although in one sense it is true that they are very generally
distributed, there are only ten definite localities where these
deposits are sufficiently important to be noticed. Of these one 1s
said to be of ‘ quartz-gravel,’ and is thus, as will be seen, of a
character different from the rest. There are also six other localities
where I have noticed them, making in all fifteen to be considered,
situated as follows :—1. The northern slopes of the Kala Dongar, in
Patcham.* 2. The summit of the Gora Dongar, north of Andhou.
3. In the glens at a considerable elevation in Bela. 4. On the
northern flanks of the Habo Hills, near Kotae. 5. Below Roha Hill.
6. High up on the Kas scarp. 7. On the south side of the Jhurio
Hills. 8. In the valleys of Varar Hill. 9. At Baukha, where it is
quarried. 10. On Bhujia Hill. 11. At the base of Katrod Hill.
12. In the Katrod Hills between Ler and Jadura. 13. Ina valley
north-west of Godpur. 14. On the Mandvi road, where it is
quarried. 15. At the base of the trap-escarpment at Khedoi. It
will be observed that the deposits are all very local, and usually
associated with some hill. They appear also to be absent or
inconspicuous on the western side of Cutch. (See Map, opposite.)

If we examine now more closely their mode of occurrence, some
remarkable peculiarities become obvious, which should be some
guide as to their origin. Thus the Kala Dongar Hills* have a steep
escarpment on their northern side, and the slopes below have usually
a direction parallel to it, but near the western end there is a
projection of high ground forming a kind of bay which opens on the
west, and it is in the angle of this bay that the subrecent concrete
is found. In the Gora Dongar, north of Andhou, a broad open
valley is formed by a dome of: Jurassic rocks, the eastern side
of which is bounded by an escarpment of limestone rising towards
the north. Near the summit the continuity of this escarpment is
broken, and we find a narrow recess of which the mouth faces west.
lt is on the two flanks of this recess that the concrete occurs,
occupying nearly the highest level in the neighhourhood, which,
from the figures given on the Trigonometrical Survey map, must be
some 560 feet above the level of the Ran. In the glens of Bela these
deposits lie, as noted, at a high level. On the northern flanks of
the Habo Hills the principal part lies on the southern slope of an
outlying scarp, and reaches a height of 300 feet above the Ran. In

* Mem. Geol. Surv. India, vol. ix. pt. i. (1872) p. 85.

? The spelling of the names is in all cases that found on the Trigonometrical
Survey Maps; but the local pronunciation, as given by Mr. Wynne’s names, is
often very different, unaccented a being pronounced as a short w, and d, /, and
r being often interchangeable.

° The Kala Dongar Hills run along the northern half of Patcham, and the
Gora Dongar Hills along the southern half,

226 REV. J. F. BLAKE ON SOME [May 1897,

the three localities south of the same hills the occurrence is very
instructive. Here a long east-and-west valley is bounded on the
north side by gently sloping surfaces, and on the other or south
side by a long and very uniform escarpment. This, however, is
broken at one place where the pass over the summit crosses, and
shows a kind of notch in the outline, which is the only spot where
the subrecent concrete occurs. It here reaches its highest elevation,
being not more than 100 feet below the summit of the escarpment,
and therefore about 700 feet above the level of the Ran. Towards
the east the valley closes in, and we reach the watershed below some
high hills. It is on the west side of this watershed that the greater
part of these deposits of concrete occurs, while there is very little on
the east (see fig. 10 in Mr. Wynne’s memoir). On the south side of
the Jhurio Hills there is a fairly continuous encircling scarp which
faces north. The main drainage of the southern slopes of the inner
hills escapes through a gorge in this scarp, which at one time was
fairly broad, but is now nearly choked up by the concrete, while
within the scarp we find the concrete spreading out as a thick white
mantle over a square mile of the slopes beyond. Notwithstanding this,
the outer slopes of the scarp, up to within a few hundred yards of the
gorge, are quite bare, the solid rocks being everywhere visible. At
Bhujia Hill the deposit is found in a semicircular valley which
opens on the south. Between Ler and Jadura there is a long east-
and-west valley, opening to the east, and this is almost entirely bare ;
but at one place a basaltic dyke crosses the valley like a wall, and ©
on the west side of it the concrete is piled up in places to its summit.
A similar phenomenon may be seen in the valley north-west of
Godpur. Where the Mandvi road crosses the Charwar range, it
traverses in one place a valley whose streams run west, and in this
valley we find the concrete on the north side resting against the
Jurassic prominences as seen near the Mandvi road. Farther east
the locality Khedoi, where Mr. Wynne records this concrete, is
situated in a semicircle eroded back from the general line of the
trap-escarpment.

In structure these deposits are very uniform. Leaving out of
consideration for the present the large stones derived from the
nearest solid rocks, which they sometimes contain, they consist of
fine particles very slightly agglutinated, so that a blow of the
hammer shatters them to dust. Some southern varieties, however,
are tougher, and are used for building, while on reaching the
extreme north-east in Bela we find them scarcely consolidated at all.
They are for the most part obliquely laminated, and in this case the
slope of the lamine in the part of the deposit nearest to the solid
rock is in the direction of that rock.

In composition the majority are mostly white sand, cemented only
with calcareous matter. In the more southerly exposures there are
calcareous particles also, but I have not seen any that are truly
oolitic. The complete rounding of the particles gives the rock that
appearance, especially in the deposit near Kotae, but on examination
they appear to be organic fragments, and there are white specks

-_—

Vol. 53.] SUPERFICIAL DEPOSITS IN CUICH. 227

which consist of little-worn miliolines. These organisms belong, of
course, to the deposit itself; but the concrete is in the habit of
enclosing what it finds on the spot. Thus at Bhujia Hill it is full of
the fragments of trap that have fallen from the summit; on the
Kas scarp it encloses the little Buliminus which is now living in
the district, and in Bela it is said to enclose human bones, though it
is not stated definitely that the deposit there was undisturbed.

Such are the facts with which we have to deal in attempting to
discover the origin of these curious deposits. Their constant
association with hills, and their occurrence in the glens, might
suggest at first that they are a rainwash, more or less transported
by rapidly descending water, on account of their lamination. But
this seems impossible. In some cases, no doubt, the solid rocks
might yield the sand, but it would be ferruginous, not white,
and such sandstone-rocks would yield very little calcareous matter.
But in other cases there is no sand in the neighbourhood at all.
Thus<in the Gora Dongar all the hills are of limestone, and the
deposits are at the very summit. The same may be said of the
deposit in the Jhurio Hills and in Bela, while the miliolines at
Kotae cannot possibly be of local derivation. Moreover, the deposits
he on a great variety of rocks, and yet have an uniform character.
We may therefore dismiss this explanation.

Another alternative is that they are marine deposits. This would
involve a depression in quite recent times of 700 feet or more, and
would in no way account for their peculiar local distribution, nor for
their lamination. One might also expect marine shells when
delicate Bulimint and tiny miliolines have been preserved. But
greater than all other difficulties is that of their loose porous
character. So far as my experience goes, no deposits that have been
laid down in water are of similar character. The water invariably
aids the particlesin packing together at their closest, and with such
materials as these they would form a solid rock.’

There remains, so far as I can see, but one other alternative, and
that is that they are eolian in origin, and this will, I think, be
found to account for all their peculiarities. It would need, however,
a strong wind to raise sand up to 700 feet in one place and 560
feet in another, and carry the miliolines from the nearest sea. We
must therefore enquire whether there are such winds in Cutch.

The Meteorological Office in Simla publishes every day a series of
observations showing, amongst other things, the average rate per
hour for the last 24 hours, and the direction of the wind at 8 a.m.
We cannot gather from this what was the direction of the wind at
other times, for if the direction has changed the time of the change
is not recorded; but by assuming that the direction at 8 a.m. is the
same as that for 12 hours before and 12 hours after, we may arrive

1 Mr. Wynne (op. cit. p. 103) speaks of a small patch of littoral concrete full
of shell-casts on the northern side of Patcham, about 20 feet above the Ran ; but
he does not classify this with the ‘subrecent concrete,’ which he says is unfos-
siliferous.

228 _ REV. J. F. BLAKE ON SOME [May 1897,

at a rough estimate of the average direction and speed. Taking the
year 1895, and treating the records in this way, it appears that the
air travels at Bhuj, in the various directions, at an average rate of
103 miles per hour for the whole year. But at the end of this
time, the air is not found to have returned upon itself. According
to the records, a particle of air which travelled constantly with
the wind would find itself at the end of the year 66,000 miles
to the east and 9600 miles to the north of its initial position.
These figures, of course, are merely indicative of general results, the
meaning being that there is, on the whole, a constant passage of air in
one direction, from a little to the south of west, at a rate of 73 miles
per hour, .

We shall form, however, a better idea of the action and power of
the wind by examining the records in detail. There were, in the first
place, only 40 occasions in the year when there was any east in the
wind at all, and the total velocity of such winds was only 123 per
cent. of that of the westerly winds. Again, for the greater part of the
year the winds are not excessive, but out of the 140 days between
April 25th and September 11th, no less than 90 days’ gales are
recorded, 7 of which are specially recorded as dust-storms. If now
we confine ourselves to these dates of gale we find that the average |
velocity was 20 miles per hour, and the average direction about 20°
south of west. The velocity exceeded in six cases 30 miles per
hour. This is an average for 24 hours, and, as gales do not
continue to have a constant velocity for so long, there must have
been not infrequent times when the wind was moving at 40 miles
per hour. The complete records for other years I have not been able
to consult, but there is no reason to believe that 1895 had a maximum
of wind, nor are we sure that the present winds as a whole are equal
in intensity to those of some period of the past. We have, therefore,
good reason to believe that there is adequate force available to do
the work required.

Moreover, similar work is now being done, as witness the dust-
storms for which Cutch is famous. As, however, the gales blow
from the west, it is Important to know what happens in that direc- .
tion, and on consulting the Meteorological Reports above quoted
we find that there were no fewer than 55 dust-storms recorded at
Karachi during 1895, mostly under westerly winds, and in the other
stations next north and north-east of Cutch 53 dust-storms and
53 dust-hazes, which latter may be taken to mean the transport of
the finer particles of dust. It is obvious, therefore, that the passage
of fine sand, etc., across the country is a widespread phenomenon.

We have evidence also that the sand thus carried travels with
great velocity, for, as shown on p. 456 of the 2nd edition (1893) of
Blanford & Medlicott’s ‘Geology of India,’ there are in Sind two
types of sandhills—one lying transverse to the prevailing winds and
the other parallel to them, the direction here being about 30° south
of west. Now it is only necessary to study the drifting of snow to
see that, while comparatively gentle winds make transverse drift,
the snow that is borne along tumultuously by the wind lies, when

Vol. 53.] SUPERFICIAL DEPOSITS.IN CUICH. 229

the wind drops, in long straggling lines parallel to the course it has
taken. These longitudinal sand-dunes, therefore, indicate a great
velocity of wind in the desert north of the Ran, so that we are not
surprised to learn that some of them, even without the aid of any
inclined plane of solid rock below, are able to attain a height of
400 to 500 feet. That the same phenomena are found in Cutch
itself may be gathered from the fact that in speaking of the sand-
dunes along the southern coast Mr. Wynne says that they have a
bearing of about 20° south of west, which is exactly the average
direction, as seen above, of the strongest winds. From personal
observation I can only say that at Mandvi, after the close of the
monsoon season, when the sea had calmed down enough for steamers
to call, the wind was constantly blinding with sand and the pier

was all buried in a dune. ‘That large areas of Cutch are now
’ covered with still drifting sand is pointed out by Mr. Wynne.?

The cause assigned being thus found adequate for the work, we
must next enquire how far it explains the special phenomena noted
above. As it was the distribution of the deposits that suggested
the cause, this must be taken first. Now all the localities may be
described as spots where a wind coming from the west or south
would be stopped by an obstacle, or where a shelter-spot exists in a
long scarp. Thus in the Kala Dongar the wind would he stopped
by a projecting high land, below Roba Hill by a watershed, below
Bhujia Hill by the hill itself, between Ler and Jadura, and also
N.W. of Godpur, by projecting dykes, and on the Mandvi road by
the Jurassic escarpments. On the other hand shelter-spots occur
above Andhou on the Gora Dongar, on the flanks of Habo Hills, on
the Kas scarp, on the south side of the Jhurio Hills, and at Khedoi
on the trap-escarpment. In some other places, as along the north
side of the Katrod Hills, and apparently at Baukha, the deposit
makes no feature on the surface, being level with the ground, and
thus probably fills originally existing hollows. To this latter
category must also be assigned the various glens in which the
deposits less abundantly occur.

It is thus seen that the horizontal distribution is exactly what it
ought to be. In the vertical direction, where the deposits occur at
high levels inland the main valleys are also high, so that there is
not a great difference of level; but in the case of the Gora Dongar,
where the deposits are 560 feet above the neighbouring Ran, there is
a gradual rocky slope all the way, leading up to the hollow where
they lie. In the case of the Kas scarp the west wind would be
hemmed in by lofty hills into a gradually narrowing valley, so that
its force would be greatly increased.

The lamination may at first sight seem a difficulty in the way
of the proposed explanation, but it is not so. The principal dust-
bearing gales are in the hot season, and these will leave a deposit
of sand or calcareous dust upon any preexisting surface. Then the
succeeding rains, which are not often so heavy in Cutch as to wash

1 Mem. Geol. Surv, India, vol. ix. pt. i. (1872) p. 82. 2 Ibid. p. 12.

230 REV. J, F. BLAKE ON SOME [May 1897,

such deposits away, will cement the particles together at once, as
they do the flood-deposits along the riversides. Thus each lamina
will represent a season’s work. That the lamine should dip
towards the rock on which the concrete rests, on the side nearest
to the rock, is what we should expect in a wind-blown deposit.
For when sand is blown against an obstacle it is thrown back again
and the wind has to pass away on either side, so that in such places
we always find an intervening valley between the mound and the
obstacle, the surface of the mound thus sloping towards the obstacle.
The loose porous character of the deposits, as already pointed out,
is against their aqueous origin, but is what we should expect in
an eolian formation, only so far subjected to water that it has
been rained upon. ‘The uniformity of general character over a wide
area, independently of the rock below, is thus fully accounted for.
The more calcareous composition of the southern deposits is due to
- the fact that the materials here are mostly derived from the sea (hence
the milioline also), while farther north the dust is reinforced by the
breaking-up of the Jurassic sandstones. The enclosure of the local
rocks and of the local Buliminus is quite natural, the dust finding
its way into the interstices of whatever was lying on the ground.’

(2) The Associated Boulder Beds.

These are not mentioned by Mr. Wynne, unless he refers to them
in the passage quoted above, when he writes of the concrete that it is
‘sometimes conglomeratic’ (op. cit. p. 81). Asno xolian deposit can
be in itself conglomeratic, these boulder-beds require explanation.

I will first describe the three localities where I have observed
these beds. The first is in the banks of a river running out from the
Habo Hills at Fulae near Kotae, where the subrecent concrete has
been above recorded. Here we find the following section (see
fio).

The bed of the river and about 4 to 6 feet of the vertical sides
are composed of Oxfordian shales dipping at a very high angle.
Their surface, except for the river-erosion, is nearly flat, and
immediately on the top lies a 5-foot bed of rounded and subangular
stones, from the size of a quarto book downwards, embedded in a
fine loamy material without any stratification. The boulders lie
irregularly jumbled together, with a tendency, however, for the long
axes to lie horizontally, so that the deposit has very much the aspect
of a boulder-clay. Over this comes 7 to 8 feet of false-bedded
concrete, and then follows another boulder-bed 5 to 12 feet thick
up to the top of the cliff, in which the boulders are smaller, about
the usual size of coals in a scuttle. All the boulders, so far as
observed, can be matched in the neighbouring hills. The stratifica-
tion is approximately horizontal; but the boulders only commence
some way down stream, away from the outer slopes of the hills

1 Tf this be the true origin of the calcareous surface-deposits of Cutch, it is

probably also the origin of the foraminiferous rock of Porbandar, which too is
local and is backed by a range of felsite-hills on the north and east,

Vol, 53.] SUPERFICIAL DEPOSITS IN CUICH. 231

and below the spot where the Miliola-bearing concrete is seen
resting directly on the Jurassic rocks.

The second locality is on the south side of the Jhurio Hills, in
the concrete-filled gorge and beyond. The description of these
deposits would be practically a repetition of the last—only the
thicknesses are somewhat greater, and the bed-rock is not reached in
the stream-bottom, where the boulders are seen in the sides.

The third locality is a more remarkable one, namely, that on the
north side of the Kala Dongar in Patcham. It was here that the
boulder-beds were first noticed and called loudly for some explana-
tion. At this spot there are marked on the map of the Trigono-
metrical Survey two long projecting elevations running out at right
angles from the Jurassic escarpment, where it is coated with the

Fig. 1.—Section on stream west of Kotae.

ee tiles
EEE
Bega

CALA
eS

A = Oxfordian. = False-bedded concrete.
B = Boulder-bed. D = Smaller-boulder-bed.

subrecent concrete. These no doubt were originally one, the end
having been eroded along the dividing watercourse. Their length
is 5%, mile, the united breadth 3 mile, and their elevation (not
marked on the map) is perhaps 100 to 150 feet above the plain.
They have the general aspect of the tip-heaps of a cyclopean
railway-embankment in course of construction. As seen weathered
on the surface they are covered with large fragments of rock from
3 cwt. downwards, more or less rounded, but not scratched, and
all to be apparently matched in the neighbouring Jurassic hills.
Where a section is seen the matrix is rubbly, more or less tufaceous,
and tough enough to form a cliff. At the base of the valley
laterite is found, and the long mounds appear to rest upon it.

939 REV. J. F, BLAKE ON SOME [May 1897,

Tn the first two localities the stratification in alternate boulder-
and non-boulder-bearing beds may be without discussion assigned
to the action of the streams when they were depositing and not
eroding, but in all three cases the difficulty is to account for the
carriage of the large stones and their promiscuous heaping together.
The principal agents that have been supposed to possess sufficient
transporting power are ice, torrents, and sea-waves. In a place
where the present range of temperature is between 70° and 120°, it
is scarcely feasible to call in the aid of ice, and certainly sea-waves
are out of the question. In the first two localities, where the
boulder-beds fill up the bottom of valleys at the end of gorges
leading out from lofty domes, the bottom beds may be fairly
ascribed to the force of the water, with or without further aid; but
those which oyerlie the soft concrete could scarcely, one would
think, be borne along in so rapid a torrent that they could not
even be sorted, without that torrent eroding the surface below.

For the third locality, however, there seems no possibility of calling
in the aid of a torrent, as there is no gathering-ground for the water.
The whole history of the deposit must at the outside be confined
within an area of 1? square miles on which no longer line than
23 miles can be drawn, with a maximum difference of elevation of
1150 feet. But the mounds point in the direction of the scarp
only 1+ miles distant and whose highest point is only 640 feet
above their surface, and for three-quarters of this distance the
boulders occur. Nor do they fill up a valley, but form mounds on a
flat surface. The only area whence the water could be obtained to
form a torrent would thus be the slopes of the hills opposite the
mounds, with an average fall of only 320 feet. This appears to
me quite inadequate to produce a torrent sufficient to carry large
stones over a nearly level surface for ;*, mile. If we take the
longer oblique line and greater height the difficulty is found to be
not lessened but increased.

In the 29th volume (1873) of the Journal of this Society, p. 493,
Dr. W. T. Blanford describes similar deposits on a far larger scale
in Persia. Here there are boulder-ridges extending for 5 to 10
miles from the foot of the hills, with a fall of their upper surface in
that distance of 1000 to 2000 feet. He says that the large fragments
are commonest near places where small streams issue from the
higher ranges, but the mounds increase in quantity towards the north
and east, where the rainfall is less. I thought that this last fact would
have led the author to enunciate the theory which I am about to
expound, but he argues only that there must have been a greater
rainfall in past times, and that lakes were thus produced—without
saying how even then these boulders could have been transported for
5 to 10 miles with so little fall.

In Cutch these boulder-beds occur only where there are deposits
of eeolian origin, and in Persia they are most abundant where there
is less rain and therefore presumably more dry sand to be blown
about, so that some connexion between the two is suggested. It
appears to me that, if we suppose that at one time there was more

a

Vol. 53: | SUPERFICIAL DEPOSITS IN CUTCH. 233

blown sand present, so as to make a greater slope, the weathered
blocks which fell on it from the hills would, under the influence of
the rains saturating the sand below, slip gently forward along the
slope, supported by the underlying sand, till they reached their
farthest destination without sinking to the bottom. Thus the
eolian deposits have served as the carrier (see fig. 2).

Fig. 2.—Boulder-beds in the north of Patcham.

A = Boulder-beds. C= Jurassic rocks.
B= Subrecent concrete. D= Hypothetical former extension of
coucrete with boulders.

This explanation is analogous to that made use of by Sir Wyville
Thomson to account for the forward motion of the stone-river in
the Falkland Islands,’ and, if it be a true one, it is possible that it
may in some cases account for deposits of loose blocks which have
been referred to glacial action. There will always be antagonism
between this process and the running away of the water in definite
channels, and at last, when the slope of the zolian deposits became too
low, the growth of the mounds would cease and the streams would
begin to sensibly denude the deposits, and even cut channels in the
bed-rock. It might be thought that ali along the rain would wash
the sand away and let the boulders drop, but we see that as a matter
of fact it does not; besides which, the boulder itself protects the
sand below it, as in the case of earth-pillars, and what is washed
away above or below will be replaced by the next dust-storm.

(3) Infratrappean Grits.

These deposits, lying as they do below the traps, cannot in strictness
be called superficial, but it will be seen that they were probably of
that character—that is, deposited on the land before the traps
were poured on the top of them. This is what Mr. Wynne says of

them :—‘These form a peculiar, soft, loosely granular, and obscurely

stratified group of earthy and sandy rocks, largely composed of
trappean materials . . [they] are frequently associated with the base
of the stratified traps, but they also occur in separate patches over
the country, and sometimes at a considerable distance from them.
They are clearly beneath the trap in some localities; in others they
fill up hollows in the Jurassic beds, the planes of stratification not

1 ‘Nature,’ vol. xv. (1876) p. 359.
Q.J.G.8. No. 210. R

234 ? REV. J. F. BLAKE ON SOME [May 1897,

being conformable even to the surfaces of the hollows which they
occupy.’?

In the detailed description, however, I can find only eight places
where they are recorded, namely, west of Bhachau, Bhujia Hill, two
places north of Katrod, Rhojla Hull, ‘Khirgreea,’ Rampur, and
Lakhapur. The letter d by which they are indicated is also marked
on the map at Sanosra and west of Mundhan. Of these, one of the
localities obviously represents, by the description, some fault-rock
only; that at Lakhapur and west of Mundhan is related to an intru-
sive mass of igneous rock which the deposits do not underlie, but
merely abut against, so that they may possibly belong to the subrecent
concrete. Of the deposit at Rampur, it is stated that ‘it may have
been the basal portion of the trap series.’ It is not connected with
the trap of the neighbourhood, and consists of ‘ scoriaceous lumps of
trap mixed with sand, etc., so that this also may be an old variety of
subrecent concrete. Of the other deposit north of Katrod, we read
that beneath the trap is ‘a hard bed of black ferruginous grit ;’ it
therefore contains no trap-fragments, and may perhaps be dismissed as
doubtful. There remain, therefore, five spots where peculiar deposits
are actually found below the traps, with a sixth at Artara, unrecorded
by Mr. Wynne, and in no case are they large enough to map.”

These six may also be grouped together, for those at Artara and
at Sanosra are of the same character, and those at Khirgreea and
Rhojla Hills are described as similar to that at Bhujia Hill. There
are thus, with that west of Bhachau, three types of such deposits.

I have thought it necessary to thus analyse the evidence on
account of the statement that they are ‘ largely composed of trappean
materials,’ which is difficult to understand if they are infra- and —
therefore presumably pre-trappean.

We will first examine the deposits on Bhujia Hill. The following
are the only two sentences in Mr. Wynne’s memoir which give us
his description of them :—‘ To the eastward from beneath the highest
summits, the basalt is underlaid by, and intercalated with, a rapidly
increasing mass of soft, ? ashy, sandy rock of greenish-yellow colour,
passing in places into a hard siliceous trappoid sandstone of coarse
texture, containing fragments of woody plants. ..... From Bhoojia to
the conical sandstone-hill on which Soorul temple stands and near
the latter, the subtrappean grits are occasionally seen; the trappean
blotches and interstitial portions weathered out into little cavities
on the surface of the rock, which sometimes occupies pockets or
wide fissure-like spaces in the underlying Jurassic beds.’* With this
description I am in perfect agreement, but the accompanying map
and section do not correspond to it, and I am at a loss to understand

1 Mem. Geol. Surv. India, vol. ix. pt. 1. (1872) p. 56.

2 On Mr. Wynne’s map there is marked a considerable expanse of infra-
trappean rocks in the neighbourhood of Bhachau, but there is evidently some-
thing wrong here. A distinct unexplained colour is inserted, and the details
do not correspond with the text. Moreover, the deposits are not overlain by
the traps.

3 Op. cit. p. 168.

Vol.'53:| SUPERFICIAL DEPOSITS IN CUICH. 230

them. It will be seen that, beyond calling some of the rocks ‘? ashy ’
and ‘trappoid’ and speaking of ‘trappean blotches,’ the author
speaks of nothing but grits. It is true that in some parts they are so
much and so irregularly discoloured, apparently by infiltration, that
they then bear a superficial resemblance to some rocks of volcanic
origin, but their essentially gritty nature is unaltered.

The best exposure is on the northern slope of the hill, where the
section shown in fig. 3 is seen. Here the bulk of the hill is com-

Fig. 3.—Infratrappean grits at Bhujia Hill.

RYDE Ty
' j muses!
ST ie eer peqeraenis pole
4 : :
PAL PCE DRS x STAY Aa: cits

Sal Ditayoys i!
rr se

A = Jurassic rocks. C = Trap.
B = Infratrappean grits.

posed of the Jurassic sandstones, which on the western side rise
up and meet the capping of basalt. Hast of this junction there
comes in rapidly a series of thick beds of very porous character,
all of which are laminated, but not conformably to the base on
which they lie. Their porous character gives them a very ‘ashy’
appearance—that is, the appearance of fine débris deposited in the
open air; but they are almost entirely composed of sand-grains
lying in a loose matrix of finer dust, and are so like some of
the samples of subrecent concrete that without labels they can
scarcely be distinguished in hand-specimens. The lamine ran up
to and meet the basalt above, and as we pass eastward the deposit
becomes thinner till the basalt and Jurassic sandstones come together
again. The other patches referred to as lying in the open hollows
are generally darker and more compact, but they are still sandy.
The isolation of this and similar deposits at Khirgreea and Rhojla;
its occurrence in a shelter-spot on an old Jurassic hill; its porous
character and sandy composition, all point to an eolian origin,
representing as they do the same conditions as those represented by
the subrecent concrete.

The second type of deposit at Sanosra, due south of Bhuj, and
at Artara, between the Jurassic rocks and the trap, is simply a
collection of stones derived from the rocks below, cemented by finer
material, and lying in hollows over which the trap passes: that is
to say, it is the surface-débris of the land on which the lava was

poured out.
R2

936 | REV. J. F. BLAKE ON SOME [May 1897,

The section west of Bhachau, which appears to show a third type,
I have not seen, as at the place where alone I was able, from lack
of more time, to examine the trap, it was lying directly on the
Jurassic rocks, showing, as pointed out by Mr. Wynne, the very
local character of the subtrappean group. I therefore copy here
the description in the memoir (p. 136) of the beds referred with a
query to this group, as taken from Mr. Fedden’s note-book :—

Feet.
*7, Brecciated and conglomeratic bed, lower part almost

wholly “of pink lawa,?) cc... etes ewenta de aeece-cscene eee
©. Wellow sandstones... dt sgucuur-pesceeroceecr snes eeeeeeeeee 2
5. Conglomeratic and concretionary bed of pale lavender

and pink lava ?, with large pebbles of hornstone, frag-

ments of yellow clay, and fine sandstone ................6. 1-4
4. Hard, yellow and pinkish, gritty sandstone ............... 5’

It will be seen from this description that the only ingredients which
could not be derived from the Jurassic rocks are the fragments of
‘pale lavender and pink lava?’ I think itis very doubtful whether
these are really volcanic fragments. Even Mr. Fedden queries
them, and as the large area south of Bhachau, mapped as trap, is now
seen in the cuttings of the new road to be entirely lateritic, it is
more probable that the fragments here noted are also of that
character. Perhaps, however, it comes to the same thing if laterite
is derived from trap, in which case the basalt of Bhachau must be
one of the later flows. The stratification also of these deposits
indicates the agency of water, so that we may perhaps sum up as
follows :—

The subtrappean rocks are all superficial deposits on the pre-
trappean land-surface, those at Artara and Sanosra being the
ordinary results of weathering : those at Bhachau, the washing-down
of similar débris onto a lower, water-covered level; and those of
Bhuyjia Hill, etc., eolian drift.

Taking this last in connexion with the subrecent concrete, we
have thus a record of the constancy of the meteorological con-
ditions in Cutch, from recent times as far back as the Cretaceous
epoch.

(4) The Laterite.

The deposits hitherto dealt with are on a small scale and more or
less peculiar to Cutch, but those which remain to be discussed are
widely distributed in this part of India.

The various deposits which in different parts of India have gone
by the name of laterite are, with exceptions, superficial in origin.
As, however, the term has been so widely applied that the only
definition which will cover all the varieties is that it is a very
ferruginous rock of peculiar character, it follows that the rocks
included under this definition may be of many origins and of many
ages. All the laterites of Cutch are classed and mapped by
Mr. Wynne as ‘sub-Nummulitic,’ so that they stand, with those of

Vol. 53. SUPERFICIAL DEPOSITS IN CUICH. 237

the Nerbudda valley near Surat, as the only laterites which lie
below well-defined marine deposits.

That there are lateritic beds below and associated with the
Nummulitic Series in Cutch admits of no dispute; but those whose
age can thus be proved all lie on the south side of the trap-escarp-
ment and rest immediately on the trap itself, where there can be
little doubt that the lower red earthy varieties are the products of
decomposition wm situ. It is with an entirely distinct area that I
am concerned, where the laterite is separated from the trap by miles
of intervening Jurassic rocks and Ran, and is overlain by nothing
but alluvium. That these also are sub-Nummulitic depends on the
assumption that all the lateritic deposits in a province as large as
Cutch must necessarily be of the same age—an assumption which
does not appear to me to be warranted.

The superficial group of laterite is found only on the southern
and western margins of the Ran islands and along the northern
border (and eastern also according to Mr. Wynne) of Wagir. In the
course of this range it is found lying on various members of the
Jurassic series. In the north of Patcham it lies on the oldest, in
the north of Wagir on the youngest, and on intervening members
at other places.

This distribution indicates, I think, a later age than the Nummu-
litic rocks, for these latter rest upon the decomposition-products of
the trap, which do not require long to form, and they nowhere
extend to the Jurassic rocks, as they surely must have done, if
these had been already denuded to any great extent. Whereas,
before these laterites were produced, not only must the lowest
Jurassics have been exposed by denudation, but the general contour
of the country must have been not far different from what it is at
present. The only indication of age that I can quote is that they
underlie the boulder-beds in Patcham.

The laterite here is a sort of gravelly deposit, the pieces being of
fantastic shapes with a crinkly surface. They are dark red or black
in colour, and consist of concretionary and stringy ferruginous
matter, more or less closely sprinkled with sand-grains. The
several pieces often interosculate into a vacuous spongy mass, in
which case the rock so closely resembles some of the higher members
of the Jurassic series as to be undistinguishable in hand-specimens.
In certain well-defined spots, the surface of the ground is covered
with small, irregularly-shaped, and obviously detrital agates, some-
times white and sometimes tinged yellow and red. These ferru-
ginous beds are frequently seen to overlie well-stratified, soft, white
sandstones and earthy beds, which are tinged with pink and purple
by the infiltration from the laterite, as seen by the stalactitic form
of the coloured parts (see fig. 1, p. 69 of Mr. Wynne’s memoir).

Deposits of this kind are mostly found at levels relatively low,
as compared with the surrounding Jurassics, and they seem to be
limited to a level lower than about 120 feet above the Ran. They
are only found inland at spots which would become lakes if the
water-level were restored to that height.

238 7 REY. J. F. BLAKE ON SOME [May 1897,

From the preceding observations we may safely conclude that

(i) This laterite and its associates were formed in water.

(ii) They are not the result of the decomposition of any rock
mn situ. ;

(111) They are detrital in origin.

(iv) They were formed at a time when the surface of the country
was not very different from what it is at the present day, but when
the water-level was 120 feet or more higher than now.

As to the source of the detritus, the materials of the sandstones,
etc., might easily be procured from the higher Jurassic rocks, and
the iron of the laterite itself could be found abundantly in the
same beds or in the lower Jurassics—though possibly not in a state
suited for solution. But we cannot derive the agates thence, and
agates and iron probably came together. Agates are abundant in
certain of the lower flows of trap, and to such rocks we must look
for the source of the laterite. Now, as the ‘stratified traps’ are
flows without pipes, and in the Jurassic area to the north of them
there are several pipes without flows, it has been natural to connect
the one with the other; and if the southern traps were emitted
from these pipes, there must have been flows also to the north.
Here, however, is a sharp anticlinal visibly bringing in the higher
Jurassics, so that the relics of such flows would now be hidden
beneath the Ran ; and it is from the degradation of these flows that
we may best seek the source of the laterites. This would account
for their occurrence on the north side, but not on the south side
of the inner Ran.

In the absence of any organic remains, it is impossible to say
whether they are marine or lacustrine deposits. Their resemblance
to the higher Jurassic rocks which have associated plant-beds
points to the latter, in which case we may call in the aid of vegeta-
tion, as suggested by McGee and by Mallet; but as there are
other deposits which have a similar distribution, and yet contain
remains of apparently marine shells, and as moreover a depression is
easier to imagine than a barrier, the former becomes at least equall
probable.

(5) The Alluvium and Ran.

The area marked as alluvium on Mr. Wynne’s map is a very large
one. It occupies no less than 800 square miles. A large portion
of it, however, lies along the southern margin of the province,
overlying fossiliferous Tertiary rocks, and it is to this portion that
J think Mr. Wynne’s description must especially apply, when he
says that ‘it is the result of the degradation of the local rocks,
consisting largely of materials derived from the Tertiary beds,
frequently mingled with travelled fragments brought by rivers from
the hills.’ On this part of the alluvial area I have nothing to say,
but of those parts which are in relation to the Jurassic rocks the
above is scarcely a suitable description. In these I have found
no evidence that the materials are specially of local origin or of
Tertiary derivation, and no travelled fragments have been any-

Vol. 53.] SUPERFICIAL DEPOSITS IN CUTCH. 239

where seen by me. The history, in fact, of these portions must be
somewhat exceptional and instructive.

The alluvium comes into relation with the Jurassic rocks (except
In the lateritic and a few other, possibly marine, patches of similar
age, which have contributed no recognizable elements to it) in the
broad flat area which joins the mainland of Cutch, north of Bhachau,
to Wagir, continues round the western and northern sides of that
district and unites it to Bela, skirts the south-western sides of the
islands of Kharir and Patcham, and forms patches here and there
along the northern coast of Cutch proper. With the deposits of this
area must be classed about 650 square miles of lower-lying land,
still occasionally flooded, known as the Bani, which lies in the
middle of the area between the mainland and Patcham and
the deposits on the floor of the Ran, which may be divided into the
inner Ran, south of the islands, and the outer or Great Ran, north
of them. All these areas pass insensibly into each other, being
merely distinguished by the relative heights of an undulating
surface above the general level of the sea.

In the area mapped as alluvium there are parts which become
muddy in the rains, and these pass gradually into Ran; but a larger
portion is sandy soil, which soon becomes dry, including vast tracts
where the sand is all loose and where no amount of rain can remain
for an hour on the surface.

The characteristic deposit of the Bani is a very fine micaceous
silt, and the surface is dotted over with groups of trees which stand
round the margins of artificial tanks, or near the wells which are
known to be abundant here. The surface of the Ran, in the wet
season, is everywhere covered with the slimiest of muds, on which
the camels can scarce maintain a foothold; but this is probably
underlain by a firmer, perhaps sandier deposit, as below the first
two or three inches the ground is firm and may be easily traversed
while covered with water.

Before attempting the history of this strange area, attention must
be drawn to the further features which may help to elucidate it.
One of the most important of these is the aspect of the Ran where
the alluvial deposits are absent. It has been shown long ago by
Dr. Blanford! that both the Ran and the sandy desert on the north of
it may be reasonably concluded to have been formerly occupied by the
Sea, and the latter to have been since more or less choked by blown
sand. Mr. Wynne? quotes the numerous statements that have been
made that the Ran was navigable and provided with various ports
within the period covered by native traditions, though, in describing
the Kharir cliffs (p. 106), he appears to be doubtful of the geological
evidences. In one placein Patcham (op. cit. p. 27) he quotes a deposit
with ‘marine shells nearly 20 feet above the Runn’ as ‘traces of
this old sea’; but elsewhere he states that these ‘shells’ are casts
and may be ‘very new Tertiary.’ They are therefore no evidence

* Journ. Asiat. Soc. Bengal, vol. xlv. pt. ii. (1876) p. &6.
? Mem. Geol. Surv. India, vol. ix. pt. i. (1872) p. 26.

240 | REV. J, F. BLAKE ON SOME [May 1897,

that before the sea left in comparatively recent times it stood
20 feet higher than the present surface ot the Ran.

Standing by the edge of the Great Ran, on the northern shore of
Patcham, Kharir, or Bela, one might fancy oneself looking over ,
flats which have just been deserted by the tide. Save for the
absence of the scraps of sea-wrack and the greater firmness of the
mud, there is little to distinguish the appearance from that which
might be seen along the coast of Britanny and Normandy between
St. Malo and Mont St.-Michel. Here, too, are the clean-swept
foreshore, the low cliffs on its landward margin,’ the broken
‘tumbled masses on the slopes, and the frowning scarps above, all
recalling the aspect, though wilder in type, of the Undercliff of
the Isle of Wight, where the le of the strata also is the same as
itishere. But, since the formation of the laterites and other minor
deposits, there is no evidence that the sea has stood at a higher
level than when it washed the low cliffs that now edge the Ran.

Why then has the sea departed, as it were yesterday, and left its
bed to be dried up by the sun? ‘Two explanations are possible:
either the sea has been dammed out of the area by deposits on its
surface, or the land has relatively risen. If the former were the
sole explanation, the level of the borders of the Ran would still be
uniform. But, according to the figures on the Trigonometrical
Survey maps, it would require a depression of about 30 feet to bring
the sea-water to the edge of the inner Ran along the northern
shores of the mainland, whereas on the edge of the eastern side of
Kharir it would require no more than 5 or 6 feet. ‘The land
therefore must have risen unequally, which is not an improbable
counterpoise to the depression that has taken place over the Sindree
basin.

But that deposits also have taken place and that the peculiarities
of the Ran result from these will, I think, appear probable from
what follows:—In the first place the Ran proper is extraordinarily
level ; this may be seen from the figures on the Trigonometrical
Survey map, where, over wide areas, we find 1, 3,5, 4, 8, 11, 12 feet,
showing a difference of very few feet, and I have myself ridden
over 10 miles of it in the rainy season with water on it almost all
the way of never greater depth than the knees of the coolies, Yet,
beneath the lofty scarps of Patcham and Kharir with their broken
undercliff, the shores are swept quite clean, and the débris must
have been carried away when these shores were in the making, and
when the small cliffs, sometimes 30 feet in height, were being worn
away. Now, in such a shallow sea as the Ran would be if the
water returned no waves or currents could originate, nor would the
harbours, of which tradition tells, be restored, and I conclude that
in former times the bottom must have been deeper and have been
since filled up.

* Ido not specially quote in this connexion the curiously worn cliff figured
by Mr. Wynne as ‘? sea-cliff,’ because it happens to be composed of irregularly
hardened sandstone which even inland weathers into similar fantastic shapes,
as near Mundhan.

Volt 53.) SUPERFICIAL DEPOSITS IN CUTCH. 241

Again, the Ran is traversed by no rivers; some of those from
the northern side of the mainland reach its edge, and the projecting
higher alluvial land in their neighbourhood may be taken to repre-
sent their deltas. But the great majority begin and end without
reaching it. At the lower end they break up into constantly sub-
dividing branches, which dwindle away to nothing. Im this latter
ease all the water which runs even during the heaviest rains is
absorbed by the porous soil, and sinks in before it can reach the
Ran; in the former case the quantity and velocity of the water are
too great for this to be entirely effected, and the remaining water
spreads out in a broad sheet on the surface, and so helps to flood
the Ran. In the higher parts of the Bani, and in the alluvial
area west of Wagir, there are a number of short nullahs, which
begin and end in the middle of a flat surface, and sometimes follow
each other in a broken line. They indicate the course of under-
ground streams, the roofs of which have fallen in and exposed them
in places. Such an underground course must be due to the original
valley being filled in with loose and porous material, into which
the water sinks. This it may be actually seen to do with great
rapidity. I have known 4 inches of rain to fall in the course of a
night, and the rivers to be torrential in the morning, but before
evening to be all dry again; and one can watch the water sinking
in on the bottom of their beds.

The nature and origin of these deposits can also, I think, be
determined. With regard to the Bani, as it is separated both from
the mainland (except at the two extremities) and from Patcham by
an area of Ran, it can hardly be ‘a bank formed ... by the discharge
of the Cutch streams,’ while the fine micaceous silt of which it is
composed could scarcely be obtained from thence. Its composition
and the power which it has of retaining water indicate rather that
it is a relic of the sea-bottom, corresponding perhaps to a higher
level of the submerged bed-rocks. The highest part of the alluvial
area between Wagir and the mainlard lies in the direct line of an
anticlinal which passes from one area to the other, and is doubtless
continuous. This may have origuated the higher level here.

With these two exceptions, tle whole of the features may be put
down to the wind and rain. The importance of the former may be
argued from the wide sheets of loose sand that lie to the west of
Wagir and on the south-western edges of the islands. These are
comparatively scarce on the margin of the mainland, and entirely
absent along the northern island-coasts: that is, these sands occur
where the prevailing strong winds will be stopped and are lacking
on the lee of high grounds. Moreover, the rivers that reach the
Ran on the north side of the mainland (with one exception where
there is higher Tertiary ground to the west) are deflected to the
west by the accumulation of sand, etc., on the east; hence the
distribution of this sand may be assigned to the wind. Neverthe-
less, much of the fine dust that is carried by the gales must fall
en route and beyond the lee of the hills. Here, however, it will be
covered by water during the rains, and the finer particles will come

242 REV. J. F. BLAKE ON SOME [May 1397,

to the surface and form the mud, but the ground as a whole will be
fairly firm.

The amount of deposit from rivers must be comparatively, if not
very, small. What they bring down must for the most part be left
behind when the water sinks in, and then be distributed by the
wind. It is only when the rainfall is very heavy, 2 or more inches
in 24 hours, that it can escape on to the more impervious Ran, and
in this case it will make a comparatively small part of what has
fallen there directly from the clouds, for the depth of water there is so
immediately sensitive to the fall of rain that it cannot depend for
its principal supply on remote sources. The only material that
the rivers succeed in bringing directly to the Ran will be of the
finest mud, and it will be uniformly spread.

From these causes I believe that the whole depression of the Ran
has become shallower, just as the Sindree basin to the east has
become more contracted, and in course of time all the surface
will become ‘alluvial’ soil. There are no satisfactory means of
ascertaining whether such a diminution of the Ran is now actually
in progress, the older maps being only approximate. Nevertheless
all comparisons tend in that direction. Thus the western end of the
Bani is marked on the old maps as surrounded by Ran, but as joining
the mainland by a wide area now under cultivation in the new. ‘The
northern edge of the Bani is also separated by Ran from Patcham
in the old maps, but I found little or no mud there after 4 inches of
rain, while the Ran on the south side was under water. Mr. Wynne
mentions places where the Ran is very soft, as between Patcham
and Kharir; but itis reported as perfectly passable now. Mr. Wynne
also goes out of his way to correct the statement that Bela is joined
by alluvium to Wagir; and though no doubt in the dry season, when
both are barren, it may be difficult to distinguish alluvium from
Ran, I can scarcely think he could have done this, if so many
trees had then found root in it as are now to be seen growing in the
area. But on the lee of the hills there is certainly no change—the
cliffs of Kharir are to-day exactly as he drew them.

It will be seen from the above that the main geological agent in
Cutch is now, and for long ages past has been, the wind. The heat
of the sun expands the surface-rocks, the rain disintegrates them ;
but the wind denudes, cleaning them in one place and covering
them in another. If this be so, we can scarcely admit with
Mr. Wynne that ‘ the question of how the alluvial plains of India
were formed is not cleared up by anything observed in Cutch’; but
we may adopt, with a slight modification, another statement of his,
that to whatever causes the great plains of Sind and the Ran are
due the coast-plains of Western India may also be ascribed. These,
indeed, with their wide distribution of thick unstratified deposits of
fine soil over areas inaccessible to rivers, and their abundance of
kunkur gathered from disseminated calcareous particles, seemed to
bespeak an eolian origin, even before a visit to Cutch rendered the
activity of the wind in this quarter of the globe an observable fact.
Doubtless much of the material is brought down in the first instance

Noles 32] SUPERFICIAL DEPOSITS IN CUTCH. 243

by the Indus and other rivers, but from the neighbourhood of their
mouths this has been blown about in an easterly and northerly
direction, and has thus afforded a constantly renewed source of
fresh fertility.

Discussion,

Dr. W. T. Buanrorp expressed his satisfaction that some of the
peculiar formations of Western India had been examined by an
English geologist of experience. Indian geologists appreciated the
value of independent criticism. Taking the deposits, which varied
greatly in geological age, in the order in which they had been
treated by the. Author, the speaker said that his own knowledge
of the subrecent concrete, the Miliolite. of Dr. Carter, was small,
but the fact that the rock was said to be so calcareous that it
was In many places burnt into lime was difficult to reconcile with
a purely zolian origin. The deposits described by the Author as
boulder-beds doubtless belonged to the subaerial accumulations so
enormously developed in Central Asia, Cutch being on the edge of
the great dry region in which disintegration is in excess of trans-
porting power, and the rainfall only suffices to carry detritus,
including boulders, to a lower level, not to wash it down to the sea.
With the so-called quartzite-reefs the speaker was unacquainted.
The infratrappean grits were possibly part of a similar formation
oceurring at the base of the Deccan traps throughout the Nerbudda
valley and elsewhere, and known as Lameta Beds. These often
contained small rolled quartz-pebbles. The laterites of Cutch were
principally of Eocene age, but it was very probable that lateritic
deposits of more recent origin also occurred. Some of the peculiarities
of the rock were that the two principal types—that supposed to be
due, in part at least, to alteration of other rocks, and that which was
unquestionably of detrital origin—were remarkably similar, and
that the rock is easily reconsolidated from the detritus of an earlier
laterite. The Ran must formerly have been much deeper, and
according to tradition was navigable; but as late as the time of
Alexander the Great the Indus flowed into the western part, and
silt must have been deposited with great rapidity. Even now
silt-laden water from the sea is driven up the channels on both sides
of Cutch in the south-west monsoon, and from this and other causes
deposits take place constantly. The high elevation of the Ran
alluvium near the land-area of Cutch may be due to rainwash.

Mr. E. A. Martin regretted that he could not quite understand
how the quartzite-reefs could have been formed in the manner sug-
gested. It seemed to him that if this pseudo-stratified rock were
formed by the action of the prevalent south-westerly winds, there
would not be that thinning-out arrangement on the north-east and
east which the diagram appeared to show. If, however, the occa-
sional winds from the opposite direction were also to be taken into
account, the force of the theory was more apparent, and then the
prevalence of one wind more than another would be shown by the
north-easterly trend of the apices of the beds where the dovetailing
took place.

244 THE SUPERFICIAL DEPOSITS OF CUTCH. [May 1897,

Mr. Lameivuen was glad that the Author had called attention to
the phenomena of dry erosion, as he had touched the fringe of an
important subject which had not yet received its due recognition
from the geologists of this country. Over vast areas in various
parts of the world the surface-drainage was at present insufficient
to remove the detritus brought down the slopes by atmospheric
agencies, and the waste-material consequently accumulated around
the hills and partially buried them. The speaker had been greatly
impressed by these phenomena in Arizona, where, as Dr. Blanford
had just remarked with respect to another region, the rocky ground
often stood out like islands above the vast spreads of loose material.

Mr. Vaveuan Cornisu said that the power of the winds in the
locality dealt with in Mr. Blake’s paper was undoubtedly adequate
to carry sand to the situations described ; and that, with regard to
the calcareous nature of the subrecent concrete which Dr. Blanford
regarded as a difficulty, the blown sand of Hale in Cornwall might
be cited in support of the Author’s views. This was largely com-
posed of shell-fragments, and he had observed that it was more
mobile under the action of wind than the ordinary quartz-sand of the
sea-shore. Referring to the boulder-beds, he said that the travel of
boulders presented some curious features, which he was at present
examining. For example, a large boulder travelled badly on fine
sand because the sand was readily displaced, and the boulder sank.
Conversely, little pebbles travelled with difficulty over a bed of
boulders because they were caught in the hollows, and with diffi-
culty surmounted the humps of the rough surface. The best con-
dition for the transport of large boulders, and of blocks or slabs of
stone, appeared to be when the bed was composed of pebbles large
enough to forma hard floor, but not so large as to allow the boulder
to catch in the pits of the surface. It seemed, therefore, that to
every size of boulder there should correspond a particular size of
pebbles over which the boulder could be transported with the
minimum effort.

The AvrHor, in replying, remarked that the infratrappean grits
were, in his view, of entirely local origin and not to be compared,
except in point of time, with any deposits elsewhere; while the
presence of a single quartz-pebble in them would be destructive of
his account of their origin. He admitted that there were laterites
in Cutch of Eocene age. Those examined by him, however, which
were far more widely spread, gave no indication of age, but were
certainly neither derived from the rocks on which they rested nor
produced by the reconstruction of such as were so derived. He
very much doubted the usual statement that water was driven
on to the Ran from the Indus-mouth by the monsoon. He had
ridden over part of it towards the end of an exceptionally rainy
season, and there was less water on it than the rain that had
fallen. Moreover, the strongest winds in Cutch blow in the hot
season, but the Ran is not flooded till the rain has fallen. He
agreed with Mr. Lamplugh that the study of the phenomena
of denudation by aerial agencies in the tropics was a new experience
for an English geologist.

Vol. 53.] MR. W. 8. GRESLEY ON THE FORMATION OF COAL. 245

19. Coat: a New Exptanation of tts Formation; or the Pun-
NoMENA of a New Fossiz Puant considered with reference to
the Oriein, Composition, and Formation of Coat-Beps. By

W.S. Grestey, Esq., F.G.S. (Read February 24th, 1897.)
[ Abstract. ]

Tae Author argues that the brilliant black lamine in coal and
materials similar to those that form these laminz, which are found
in earthy coals, shales, and clays, point to the former existence of
an aquatic plant, having the general shape of the modern Platy-
cerium aleicorne, which grew in place. He believes that much coal
was formed by this aquatic ‘ coal-plant, which grew amongst the
mechanical sediments and the débris of the terrestrial vegetation
that accumulated on the floors of sheets of water."

Discussion.
Mr. Marz spoke.

(Specimens, and a series of large diagrams in illustration of his paper,
were exhibited by the Author when the paper was read. By an unfortunate
oversight, the mention of this exhibit was omitted in the Proceedings, p. xciii.
—KEp.|

246 MISS C. A. RAISIN ON THE NATURE AND [May 1897,

20. On the Narurz and Oricin of the RaventHaL SeRPENTINE.
By Miss Carnrrine A. Ratstn, B.Sc. (Communicated by
Prof. T. G. Bonnuy, D:Se., LL.D., F.B.S., V.P.G:5.yead
February 24th, 1897.)

[Puates XVI. & XVII]

ConTENTS.

Page
TPOMMCHIOR fo isdis acinlescnsbeyopadse domadan ses ceeab al Boeaee eee eee 246
I Fnvestigation' mthe Bield) 2... .i-d eee ces to<neaearie: seen 247
HY.; Mieroscopie Detatls. .2.5.5. 000 wo se-tiecee ss sendesens oee eRe eee eee 251
11, Controversial Questions 2..2-h2.4gis./hisd aes cee ees eee 254
IV. Comparison with other Serpentines from the Vosges ......... 261
V. Comparison with Serpentines from other Localities ......... 263
VE SUMMA Y, Sadie table apes webh sysasoabes shbaedsemae\araa- eee ee” 266

INTRODUCTION.

Tur general origin of the rock serpentine as a metamorphosed
peridotite is now usually admitted since the investigations, which
have become classic, of Profs. Tschermak, Sandberger, Bonney,
and other later observers. An exception is made, however, for
certain masses by some geologists. One of the most interesting
of these is that described as the Rauenthal serpentine. The
hypothesis which was put forward by Weigand in 1875+ was that
this did not originate from a peridotite, that it is indeed a meta-
morphosed rock, but is the result of the metamorphosis of part of
a gneiss. The investigation of the genesis of this rock thus has a
bearing on an important general petrological question. Exception
was taken to the conclusions of Herr Weigand by Prof. Bonney from
the study of microscopic slices.” In consequence of this, on my
return journey from Switzerland in 1895, I turned aside to visit
the Rauenthal, and brought back a few specimens, with the idea
that they might be useful in the further examination of the question
which I hoped that Prof. Bonney intended to make. As, how-
ever, it was not possible for him to visit the locality himself for
some time, he asked me to continue the investigation, which I did
in the summer of 1896, spending about a fortnight in the district.
From the numerous specimens then collected, many slides have
been prepared, the inferences from which seem entirely to corrobo-
rate the views formed on the spot. I have been able fortunately to
submit to Prof. Bonney the specimens and slides, and he kindly
allows me to state that he agrees with the main conclusions from
them as here put forward. For all the help of various kinds given
to me by him in this investigation, and for the facilities most
generously afforded for examining his numerous specimens of
serpentines from other localities, 1 would here offer my best thanks.

1 Jahrb. d. k.-k. Geol. Reichsanstalt, vol. xxv. (1875) p. 183; or Tschermak,
Min. & Petr. Mitth. 1875. * Geol. Mag. 1887, p. 65.

Vol $2. ORIGIN OF THE RAUENTHAL SERPENTINE. 247

I. INVESTIGATION IN THE FIELD.

The outcrop of the Rauenthal serpentine is marked on the French
map published in 18371 as a somewhat lenticular patch rather more
than 1200 metres from 8.W. to N.E. by 200 metres from N.W. to
S.E., occurring between ‘granulitic gneiss’ below and ‘granulite’
above. A small tributary streamlet* seemed to be fed by springs
near the upper limit of the serpentine, to fall over a steep rocky
bed westward in a course roughly determined by the northern
boundary of the outcrop, although cutting through one corner, then
to continue to the north and north-west into the Rauenthal stream.
The steep hillside is often covered with grass or a close growth of
ferns or flowers, and much of it is richly wooded. Fortunately
several paths, and, still better, the road leading beyond the Schaaf-
haus, give easy access to the area which had to be examined.

(1) Relation of the Gneiss.

In the description given by Herr Weigand he speaks of a passage
from the gneiss into serpentine. Therefore I first examined, as
far as possible, the adjacent parts of the former rock. From the
side of the path near the lower course of the above-mentioned
streamlet, and from a quarry close by, I took several specimens, one
being a well-marked hornblendic band, but the outcrop here by
the path is small, and distant } mile, or perhaps more, from the
serpentine.* The gneiss is well exhibited on the north of the stream
along the road (marked a, Pl. XVI.) cut by it in small cliffs at
intervals. his rock is foliated and banded ; it sometimes has layers
resembling a reddish granitoid rock, and others a foliated diorite ; it
is usually micaceous, and often has bands especially rich in biotite.
The general dip here and in other masses is to the west of N. or to
N.W., often at a considerable angle (45° to 60°). The gneiss, of
perfectly normal type, is seen in a large mass at about 240 feet*
north of the stream, and in a small mass, apparently in situ, about
40 feet north of the stream, or 120 feet north of the serpentine.
The actual junction south of the stream is obscured, but a sloping
cliff of muddy talus extending about 80 feet seems to be full of
fragments, some of slickensided schistose rock, such as often results
from disturbance along a junction. Serpentine forms next a mass
of tumbled big blocks, and then occurs as fragments in the earthy
bank for about 470 feet. Beyond this the gneiss apparently extends

1 Published by the Dépdt de la Guerre: scale a This map is rather

later in date than that of Kochlin-Schlumberger to which Weigand refers.
2 Marked with more accuracy on the German contour-map of the district,

not coloured geologically (scale sau): This is the streamlet along which

scattered blocks can be traced, as described by Weigand.
$ At this distance, or farther from the serpentine, some of the rock is a
hornblende-schist or foliated diorite.

* All measurements are very rough calculations, made from pacing the
distances.

248 MISS C. A. RAISIN ON THE NATURE AND [May 18097,

until we reach the granite rather north of the next tributary
streamlet.

Here, then, was the first result which J had not anticipated. No
clean continuous sections were found, showing a passage from gneiss
to serpentine, nor even from gneiss to an almost pure amphibolite,
and the gneiss seemed to be everywhere of normal type. Herr
Weigand states in regard to this rock that the hornblende ‘ gradually
gains the upper hand, and thus the rock passes through amphi-
bole-gneiss to a pure hornblende-rock, which, however, retains the
stratified aspect of the gneiss.’* Whatever changes have occurred
in the local exposures (and it would have been perhaps a help if
Herr Weigand had given a more detailed description of the parts
which he examined in the field), it is difficult to see where the
sections can have been which showed the passage stated.” As just
previously recorded, in the gneiss almost adjacent to the serpentine
(along the strike of the foliation) hornblende can hardly be found,
all the dark layers which have been cut for the microscope proving
to be micaceous; and although the mineral occurs in the valley
below? and in an occasional band on the lower slopes, this seems
but slender proof of a gradual passage to an almost pure amphiho-
lite.

(2) The Serpentine and its Relation to the Amphibolite.

The crags on the grassy and tree-covered slope consist mainly of
serpentine in situ, and these were next examined.* ‘They generally
face steeply towards the west or valley-side, and are often large
masses extending 40 or 80 or even 150 feet in length, and to a
height of 20 feet or more. Among them examples are soon noticed
of the amphibolite and of various minerals associated with the
serpentine, such as may have been found in blocks by the brook
and roadstones in the valley. The chief rock is serpentine, often
including, as described by Herr Weigand, a peculiar chlorite. That
mineral is definitely orientated, the rock is generally platy, and its
appearance on transverse and parallel surfaces is in marked contrast.
On the former it looks dull, of a rather varied dark green colour,
with slightly marked lines along the edges of the planes rich in
chlorite. If these are exposed in step-like fashion, or if the rock be
broken parallel with them, the chlorite gives a silvery glitter to the

1 «Diese letztere [Hornblende] gewinnt nach und nach die Oberhand und
fihrt so das Gestein durch Amphibolgneiss in reinen Hornblendefels uber, der
aber die Schichtung des Gneisses beibehalt.’ Op, cit. p. 197.

2 The road has been made somewhat recently, I believe, and doubtless changes
have occurred in the sections exposed. But along the smaller (and, I should
think, older) path above (marked (3) gneiss is seen, in small outcrops towards
its southern end, and in bosses north of the stream, and these are of the same
normal type.

3 This would be rather distant, as previously stated, unless more crags occur
which I failed to see, because they were hidden by the trees on the lower slopes
of the hill, and even these would not be close at hand.

4 One or generally several specimens were taken from each mass. I believe
that I examined every crag, but I certainly left no important section untouched.

Vol. 53.] ORIGIN OF THE RAUENTHAL SERPENTINE. 249

surface. In the serpentine, enstatite-crystals are sometimes seen
on the cross-fracture planes, where the chlorite is not visible. This
platy serpentine rich in chlorite can be recognized in many crags
(see Pl. XVI). In a second form of the rock the chlorite-flakes
are much smaller, more crowded, and not orientated. A third
variety is massive, dark rich greenish, not platy, without chlorite,
but containing well-developed enstatite or bronzite. Fourthly, the
serpentine may be mottled with greenish patches, or a similar
material may form streaks and laminze sometimes about 3 inch
thick ; these patches and layers are somewhat indefinite in outline.

Lastly, the peculiar amphibolite occurs in places. Where typi-
cally developed it is a beautiful mass of glittering, silvery, pale-
greenish crystal-fiakes, orientated so as to produce an appearance of
foliation. Examples of it are found in at least five of the serpentine-
crags. It often forms layers an inch or two in thickness embedded
in normal serpentine, and the two rocks are clearly distinguishable
in the crags, although the boundary is not always sharply defined,
a certain indentation or mixing being visible on close examination.

Olivine-serpentine and ‘amphibolite’ (Rauenthal) in thin section.

The darker-spotted parts represent the distinctly green portions of the slice,
which are composed of olivine-serpentine. The paler areas represent the
‘amphibolite,’ which is colourless. (x 23.)

Thus the amphibolite-bands occur not along the limit of the ser-
pentine, but included in it (see Pl. XVI). Again, the loose blocks
in the valley show the amphibolite and serpentine in similar relations.
Another mode of association, however, is exhibited in certain
loose boulders, and in one crag near to and south of the streamlet.

Q.J.G.8. No. 210. s

250 MISS C. A, RAISIN ON THE NATURE AND [May 1897,

Here angular and irregular patches of serpentine and amphibolite
are intermingled, giving the appearance of a breccia.

This occurrence of hornblendic bands and patches presumably
represents the passage of the amphibolite into the serpentine
described by Weigand. In these separate bands or streaks, as also
in the chlorite-bearing serpentine, a parallelism and orientation of
the minerals is usually found, and Herr Weigand speaks of this as if
only one cause could bring it about. He states that the serpentine
‘lies in the amphibolite and in the strike of the gneiss; it is thus
a metamorphosed banded complex of hornblende-rock.* As will
be seen from my description, the fact is rather that the amphibolite
les in the serpentine. A parallelism, however, with the foliation
of the gneiss could be explained on the theory of the igneous nature
of the serpentine and amphibolite. If amagma were intruded into
a mass of gneiss, the intrusion would be likely to follow the

structure-planes of that rock and to show a general parallelism
with them.

(3) General Character of the Gneiss.

Finally, we must notice one general difficulty. The gneiss near
the Rauenthal, as I have stated, is exposed, and exhibits a normal
character over a large area. Occasionally (I should say rarely) it
has bands rich in hornblende or composed of that mineral. In
these, the hornblende, as Weigand describes it, is the dark greenish
variety usually found in the gneiss. The rock shows the usual
alternations of layers: quartz and felspar, biotite and felspar, or
quartz, felspar and mica. Yet, on Weigand’s hypothesis, the
gneiss becomes in one isolated locality a mass of almost pure
hornblende. Nowhere else in the neighbourhood is this repre-
sentation found.” The only evidence for it here consists, first, in a
comparatively few isolated layers of the peculiar pale amphibolite
(and no hypothesis is put forward to explain the supposed bleaching
and modification of the dark mineral of the gneiss), and secondly,
in a mass of serpentine into which the hornblende-rock is supposed
to be changed. Of the latter alteration we may at least say that it
is neither usual nor easily explained. Even if there were a passage,
of which I can see no evidence, this general difficulty should have
been discussed.

On Herr Weigand’s measurements, the serpentine-outerop is
30 paces broad,? and the occurrence of hornblendic bands a few
inches in thickness would not afford much material for so massive
a development.

1 «Br liegt im Amphibolit und im Streichen des Gneisses; er ist also ein
umgewandelter Schichtencomplex von Hornblendefels.’ (Op. cit. p. 208.)

2 As Prof. Bonney points out, a large mass of either pure hornblende or
pure pyroxene is certainly very rare. (Geol. Mag. 1887, p. 66.)

3 «Die grdsste Breite des Serpentinanstehenden ist ungefahr 30 Schritte’
(op. cit. p. 197). My own very rough measurements up the steep, covered,
boulder-strewn slope gave the outcrop as about 260 yards broad. ‘This agrees
better with the map, but would increase the difficulty discussed above.

bo
Or
e

Vol. 53.] -—«-« ORIGIN OF THE RAUENTHAL SERPENTINE.

(4) Relation to the Granite.

I traced the serpentine upward, passing off it in many places
until satisfied that [ was on the granite and that no serpen'ine
occurred higher up, since fallen blocks were not to be seen. The
two rocks approach most closely along the upper course of the
streamlet already noticed, especially below the road (6) and above
the little path (y). Clambering here for a few paces at several
spots over ground covered with soil and plants, I passed in each
case from the serpentine to fragments and blocks, mostly moss-
covered, consisting of granite, but I found no actual junction.

II. Microscopic Deratts.

In the slides of rocks from the Rauenthal certain distinct minerals
can be identified. For very many details about these we may
briefly recapitulate the descriptions given in previous articles by
Herr Weigand? and by Prof. Bonney.”

(1) Chlorite.

The shining folia visible macroscopically exhibit water-clear
sections which extinguish straight, and are identified as chlorite
often enclosing extruded iron oxide. In addition, they sometimes
contain spindle-shaped crystals of another mineral *,’ probably aggre-
gates of perofskite, or perhaps in some cases an impure sphene.
The chlorite is associated either with the ordinary serpentine or
with the amphibolite (Pl. XVII. figs. 4, 6). At places it shows in
polarized light transverse bands like strain-shadows, so that it
imitates the twinning of felspar, and has almost a microcline
appearance.*

(2) Hornblende.

Clearly-marked hornblende occurs within the serpentine, in Jongi-
tudinal sections with rectilineal structure and in transverse sections
with lattice-work, both often showing partial alteration, as described
by the above-named authors’ (Pl. XVII. fig. 2). There would
be no difference of opinion that such crystals are undergoing
serpentinization, and that these serpentinized parts retain the
characteristic indication of hornblende-cleavages. The transverse
serpentinized bars may be somewhat sinuous and fringed, but the
longitudinal planes extend as straight boundaries to the kernels of

1 «Die Serpentine der Vogesen, Jahrb. d. k.-k. Geol. Reichsanstalt, vol. xxv.
(1875) p. 197.

2 ‘Note on Specimens of the Rauenthal Serpentine, Geol. Mag 1887,

. 65-70.

PP; The * indicates a mineral not mentioned in Weigand’s description.

+ J found in another slide a twinning somewhat resembling the above ina
mineral which I believe to be pyroxenic, probably enstatite. Cf. T. G. Bonney,
Geol. Mag. 1887, pp. 239, 240.

-° Id, ibid.; also J. J. H. Teall, ‘ British Petrography, 1888, p. 111.
s2

252 MISS C. A, RAISIN ON THE NATURE AND [May 18097, |

hornblende. Although the original hornblende-crystal has in the
process of change become ragged and often irregularly replaced at
the exterior by the mineral] serpentine or actinolite, yet in a few
cases a definite external form can be traced. An idiomorphic
character would not have been generally acquired in the original
crystallization of hornblende any more than in other hornblendic
peridotites or in the amphibolite of this area. The pale hornblende
which forms the last-named rock consists of crystals often bounded
by straight sides (generally prism-faces) and exhibiting perfect
cleavages, but with ragged ends (Pl. XVII. figs. 4 & 5). Most of
the mineral is fresh, but occasionally it is broken up into an
aggregate partly serpentinous, partly actinolitic, which begins in
tooth-like projections penetrating into the hornblende.

(3) Enstatite.*

This mineral can be identified by various characters. It exhibits
close parallel structure, with straight extinction, appears streaked
at least partially with serpentine, and includes, along the structure-
planes, minute tubular enclosures, or some clustered brownish
crystals, probably perofskite. The enstatite is undergoing serpenti-
nization and is similar in its characters to that which Weigand
describes as forming the major part of the Starkenbach mass, which,
partly from this fact, he infers to have an origin different from that
of the Rauenthal rock.

(4) Augite.*

Augite occurs in one slide, although it is in a layer of amphi-
bolite, and thus, according to Weigand’s bypothesis, not within
an original peridotite. The augite is colourless, fresh-looking, with
well-developed cleavages seen both in transverse and in longitudinal
sections. The crystals are partly idiomorphic (with planes 110,
101, 011) and are enclosed within the hornblende.

(5) Iron Oxide.

Secondary minerals occur, one of the most important of which is
iron oxide, commonly associated, as Weigand describes, with the
chlorite, and often in the form of hematite. Other minute grains of
iron oxide will be noticed shortly as occurring in the serpentine.

(6) Perofskite.*

In connexion with the serpentinized enstatite, small crystals
occur (about ‘025 mm. or less in diameter), sometimes in definite
cubes or octahedra, but usually clustered. The mineral is clear,
colourless, with a high refraction and rough-looking surface, and it
has whitish or silvery lustre by reflected light. It apparently is
perofskite. ,

The mineral within the chlorite (as mentioned above) has very

Vol. 53.] ORIGIN OF THE RAUENTHAL SERPENTINE. 253

similar characters. In the enstatite and in some of the hornblende,
gummy-brown granular aggregates are clustered along the cleavage-
planes, and perhaps cause a filmy appearance over intervening parts.
This also is not unlike perofskite, possibly a second form of that
mineral or a stage in its development, but it is in grains too minute
to be tested. The serpentinized hornblende in one slide encloses
small rhomboidal nets, which might be clusters of a similar mineral,
but have rather the appearance of skeleton crystals.

(7) Rutile.*

In one slide of serpentine (from a loose specimen) many of the
rounded kernels within the network exhibit acicular brownish
crystals. They are long, but too slender to be examined in detail.
Their colour and form suggest a dark impure rutile, and geniculate
twins, although not common, occur. ‘The needles are developed
usually towards the border of the kernel and point in a more or less
radial direction. The late Prof. Carvell Lewis, as will be seen from
his forthcoming work on the Genesis and Matrix of the Diamond,
identified rutile in serpentinized olivine.

(8) Serpentine.

The mineral serpentine in these slides shows varietal forms. It
may consist of tubular or fibrous elements, sometimes parallel in
bundles, sometimes in a matted mass. This serpentine is greenish,
gives yellowish polarization-colours, and extinguishes parallel to
the direction of the fibres, which thus are probably chrysotile.
Secondly, the serpentine may show the lattice-work or the somewhat
rectangular network surrounding angular kernels as described by
Weigand and others.’ Thirdly, it exhibits kernels of less regular form
which, although they sometimes have rectilinear boundaries, are
generally rather more rounded. Several differences between the last
two cases are often recognizable. These are for the most part best
seen with high powers in ordinary light by the use of a diaphragm.
The parts with angular network are paler in colour; the net gives
an effect of higher refractive power than the mesh, appearing like a
green rim bordering a colourless area. With crossed nicols, the
rim gives low colours and extinguishes nearly or quite parallel,
while the enclosed parallelogram is faintly or not at all doubly
refracting. The part with rounded grains is greener, the kernels
are paler, more highly refracting and prominent than the inter-
vening bands; where they have a greener tint we may sometimes be
looking at a band cut parallel to its plane. In either case the
nucleus has no effect on polarized light, but the borders give the
usual low colours of serpentine.

Thus, as was pointed out by Prof. Bonney, there are two type-

1 This form of serpentine results from the alteration of hornblende, trans-
verse sections of that mineral showing a lattice-structure, and longitudinal
sections exhibiting the prism-cleavages crossed roughly at right angles by less
regular lines,

254 MISS C. A, RAISIN ON THE NATURE AND [May 1807, .

forms of the serpentine, differing in several characteristics. Whether
the fibrous part is connected always with one or the other form is
difficult to decide, but it seems certainly in some cases related to the
more irregular part, since it can be traced originating either as
patches or as a fringe beginning to extend into the kernels. A
fourth form of serpentine with close parallel structure has been
noticed as the result of change in enstatite.’

Although these observations thus agree with many of the details
given by Herr Weigand, yet some additions to his list are required,
and the presence of enstatite especially has an important bearing,
as it is distinctly a mineral associated with peridotites or allied
rocks.”

III. ConrrovERsIAL QUESTIONS.

The characters must now be considered in which, according to
Weigand, the Rauenthal serpentine is unlike the other masses, and
by reason of which, according to the same authority, a different
origin must be attributed to it.

(1) Accessory Minerals.

It is stated that ‘the accessory minerals so characteristic of
olivine-serpentine here are wholly wanting.’*® It is true that
picotite does not appear to be present, but it is absent from other
serpentines, and other accessories characteristic of peridotites (perof-
skite, rutile, enstatite) are found here.

(2) Iron Oxide.

A second important distinction is stated to be that, ‘ for one thing,
strings of iron are entirely wanting, and in consequence differently
coloured zones.’® The serpentine in many parts hasa rather uniform
greenish tint, contains only minute specks of ferrite scattered within
the kernels, or aggregated in minutely granular strings along the

! A kind of spherulitic serpentine also occurs within certain veins which
cross the amphibolite. In one of these, a very pale greenish or yellowish
isotropic ground exhibits, with polarized light, scattered stars which consist of
fibres, evidently serpentine or chrysotile. A vein in another slide shows, in
polarized light, a diaper-lke pattern with black crosses similar to that of
spherulitic rhyolites. At other parts wedge-shaped crystallites grow in tufts
from the sides of the vein. I noticed a slight development of a similar structure
in a serpentine from the Lizard.

* The views of Herr Weigand as to the Rauenthal serpentine are quoted by
Mr. Teall (‘ Brit. Petrogr.’ 1888, pp. 110-112). We find it stated, however, in
another place, in connexion with Sandberger’s results, that ‘one or more of
the minerals, chromite, picotite, pleonaste, chrome-diopside, enstatite, and
pyrope, are found in the typical peridotites. The occurrence of any of these
tainerals in a serpentine is therefore strong evidence that it has been produced
by the alteration of an olivine-rock.’ (Op. cit. p. 108.)

3 B. Weigand, op. cit. p. 201 :—‘ Ferner fehlen hier im Hornblendeserpentin
ganzlich die fiir den Olivinserpentin so charakteristischen accessorischen Minera-
lien. .... Hinmal fehlen hier ganzlich Erzschnire und damit verschieden
gefarbte Zonen.’

Vol. 53.] ORIGIN OF THE RAUENTHAL SERPENTINE, 259

intervening bands, as indicated by Prof. Bonney.! Thus, even apart
from the chlorite, iron oxide is not entirely absent”; but it is true
that the strongly marked black or brownish network of many
serpentines is not here visible.

I fail to see, however, that this fact leads to any other inference
than that the original olivine was not a ferriferous variety. It
would seem that the original magma was one rather poor in iron,
for the colourless hornblende probably owes its peculiarity to a want
of the ferruginous constituent. Much of the iron oxide which is
present in the serpentine seems to be associated with the peculiar
chlorite. In certain specimens, however, the olivine-serpentine is
more ferruginous, with grains of magnetite (?) and so much scattered
minute opacite that it gives a bluish tinge to parts of the slide; but
here no chlorite is exhibited.

(3) Microscopic Structure of the Serpentine.

(1) After the accurate description of the serpentinization of
hornblende, Herr Weigand goes on to state that ‘ the same arrange-
ment is found everywhere in the serpentine,’ * and that it ‘ follows
without doubt that ....a serpentine ....in great masses .... has
originated from amphibolite.’ It was shown by Prof. Bonney that
the serpentine had not so universal and uniform a character, and
that the major part of it can be distinguished from the serpentinized
erystals of hornblende. We cannot ignore the differences which
certainly exist, which Weigand himself to a certain extent recognizes
from his words the ‘larger rounded parts.’” This phrase alone
suggests two differences ; others have now been added; and the
true explanation seems to be that the part with ‘larger rounded ’
kernels is the result of the serpentinization of an olivine-mass
(Pl. XVIT. figs. 2,6). In fact the hornblende occurs as an accessory
in an original peridotite, just as that mineral is found in parts of
the Lizard serpentine.

(2) We are told that this nena AL serpentine does not exhibit
the ‘irregular network’ which is characteristic of olivine-serpen-
tines. Here there is a network—it is only therefore a question of

1 Geol. Mag. 1887, p. 68.

2 Indeed this appears to be acknowledged, although the statements do not
seem perfectly clear:—‘ Die Analyse zeigt also in Uebereinstim mung mit der
mikroskopischen Untersuchung eine grosse Menge Eisen.’ (B. Weigand, op.
cit. p. 200.)

a "The analysis of the amphibolite given by Weigand includes Fe,O, 4°649,
FeO 2°107, but the analysis was obtained, we are told, from material aieh
included some serpentine.

4 ‘Zeigt sich dieselbe gitter- und fensterformige Structur tiber das ganze
Gesichtsfeld verbreitet’ (op. cit. p. 198); ‘.... man im Serpentine selbst
mittelst des polarisirten Lichtes den Chrysotil in derselben Anordnung iberall
wiederfindet wie in der Hornblende . . .’ (op. cit. p. 200).

5 ‘Geht unzweifelhaft hervor, dass .... wir also hier einen in grossen
Massen auftretenden Serpentin haben, der aus Amphibolit entstanden ist’
(op. cit. pp. 200- 201). § Geol. Mag. 1887, p. 68.

7 Op. cit. p. 197: ‘ grossere rundliche Partien.’
3 B. Weigand, op. cit. p. 201.

256 MISS C. A. RAISIN ON THE NATURE AND [May 1897,

the regularity in its arrangement. If there be any difference in this
respect from other serpentines, there is a far greater difference
between it and the changed hornblende.’ Moreover, in the olivine
of various rocks there is a marked difference in the amount of
internal structure which it exhibits. While in many crystals no
cleavage and only irregular cracks are seen, in others straight
parallel lines of cleavage are well developed. Perhaps no better
examples of the latter character can be found than in certain euly-
sites.” If, however, we examine for comparison other serpentines,
we find in many that bands equally straight form the network;
and the structure of the strings in the Rauenthal rock was stated
by Prof. Bonney to ‘agree perfectly with those in a normal
serpentine.’ ®

(3) In the mode of development of the chrysotile, Herr Weigand
sees evidence of the hornblendic origin of the rock. The fibrous
ageregates, however, in some of these slides have not a regular
arrangement, but form a matted mass. Again in other rocks,
parallel sets of fibres can be found beginning to develop from
olivine. Thus the fibrous serpentine may in some cases have origi-
uated by alteration of hornblende, but there seems no evidence that
this derivation is a necessity ; on the contrary, a development from
olivine can sometimes be traced.

(4) Specific Gravity and Hardness.

I have tested four specimens of the Rauenthal serpentine, and
have found in them a specific gravity varying between 2°53 and
2°62. These results differ little from those given by the Bonhomme
(an admitted olivine-serpentine),* or by similar rock elsewhere.’
A specimen of the amphibolite (chosen to include as little foreign
admixture as possible) gave a specific gravity of 2°828.

Herr Weigand further states that the serpentine of the Rauenthal
is distinguished by its greater softness (op. cit. p. 197). I find
that the degree of hardness in certain type-specimens is nearly 4:0,
while that given by the ‘ olivine-serpentine’ (Bonhomme) is only
about 3:0.

1 The serpentine-bands in the network of an olivine-serpentine seem broader
than those along the cleavages in hornblende. Further, in those slides which
are cut across the structure-planes of the rock, a fair proportion of the recog-
nizable hornblende-crystals show the lattice-structure. But if there be any
marked regularity in the serpentine, the parallelepipeds mentioned by Weigand
are mostly rectangular.

* It becomes a question whether the mode of origin of such a rock may not
be related to the more perfect cleavage of the mineral. If we could connect the
cause of this structure with the flow of the original magma of the eulysite (a
character which seems indicated in the rock), this might have an interesting
significance in connexion with structures in the Rauenthal serpentine.

3 Geol. Mag. 1887, p. 68.

* Herr Weigand gives 2°713 for the freshest rock and 2°609 for one more
decomposed (op. cit. p. 189). I obtained, for 3 specimens, 2°671, 2°622, and 2°52
respectively ; but the rock is so variable that differences are easily explained.

° For Lizard serpentines, see Quart. Journ. Geol Soe. vol. xlvil. (1891) p. 466.
Sp. gr. from 2°545 to 2:77 for 8 specimens ; one other had a sp. gr. of 2°85.

Vole53-] ORIGIN OF THE RAUENTHAL SERPENTINE. 257

(5) Presence of Chlorite.

One striking characteristic, macroscopic and microscopic, in the
serpentine is the presence of the ‘silvery scales, or the peculiar
chlorite which is stated to be one of the essential points of distinc-
tion. It depends, however, on the explanation to be given of the
formation of this chlorite whether it can be used as an argument
for the origin of the rock from an amphibolite. It was not at first
easy to come to a conclusion on this point, and the question is
partly connected with the relation of the rocks in chemical
composition.

In the supposed chemical change of a hornblende-rock to serpen-
tine, Weigand points out that there would be a decrease of silica,
a proportional increase of magnesia, and the loss of most of the
lime and alumina. For the latter changes he offers two suggestions :
the first, that these constituent substances induced the formation of
the chlorite; the second, that possibly layers might occur of poorly
aluminous hornblende.t Of the latter suggestion it is only
necessary to say that it would be as easy to demand a belief in
layers of completely non-aluminous olivine, which would grant the
whole contention. The former suggestion seems necessary to Herr
Weigand’s hypothesis, and demands the acceptance of his view that
the chlorite is a new formation. But all that can be established on
this point is that the extrusion of iron oxide and the general
affinities of the mineral suggest its being in a secondary or modified
condition. The sharp contours, however, and the general parallelism
of the flakes, to both of which facts Weigand refers as evidence,”
are surely no arguments for his view. If the chlorite were
developed in the alteration of hornblende to serpentine (using up the
spare alumina and possibly lime),’ it would be likely to occur inter-
locking with the serpentine, of an irregular form, and with a less
uniform arrangement, as is usually the case in secondary minerals.
Further, we find the chlorite sharply limited at its junction with a
hornblende-crystal, or completely embedded in an enstatite, as if it
represented an original constituent of the rock; in other words, it
seems to be the modification of a mineral with a definite form.
Although I had considered in the field the question of its develop-
ment, and even had tried to trace a connexion with more than one
occurrence of a mica, I owe to Prof. Bonney the suggestion of
what I believe to be the correct view, reconciling seemingly con-
flicting appearances—that the chlorite probably is the result of
change of a mica akin to biotite ; if so, the original rock must have
been related to a mica-peridotite. If the mica, as is probable,
was a somewhat ferruginous variety, then, where it is deficient,
the presence of a more ferruginous olivine may be explained. If

2 Op. cit. ps 202,
* Ibid,
3 Herr Weigand notices the difficulty of the lime, and makes the significant

remark that if not found in true chlorite in such large proportions it is not
unusual in the mica group (op. cit. p. 200).

258 . MISS C. A. RAISIN ON THE NATURE AND [May 1897,

the magma there was poor in the lime,’ alumina, and alkali necessary
to form mica, the iron may have been used up in the composition of
the olivine.

If, however, anyone maintains that the evidence just given for
an original mica is not conclusive, difficulties still remain in
Weigand’s hypothesis. First, patches of the chlorite occur in the
Rauenthal rock in parts where no hornblende can be traced, or
flakes are isolated within olivine-serpentine (Pl. XVII. fig. 3).
Secondly, in rock from other localities there is serpentinized
hornblende, but no indication of chlorite. Thirdly, the chlorite
occurs in Rauenthal specimens embedded among completely fresh
hornblende, and thus apparently not associated with its serpen-
tinizution. Fourthly, so far from the presence of the chlorite
differentiating, as we are told, this serpentine from serpentines
which have originated from olivine-rocks, the mineral in question
is found in the latter, as Prof. Bonney has pointed out,’ and as
will be described shortly in several examples.

Finally, specimens were found from Bonhomme, and afterwards
from the Rauenthal, in which a transition from mica to a pale
chlorite could be traced ; and, as will be shown later, the structure
of the platy serpentine would agree with this origin of the chlorite.

(6) Chemical Changes.

If the chlorite be thus a modification of an original mica, the process
for the formation of the serpentine from a hornblende-rock would
be quite inexplicable. The alumina (and possibly other constituents
of the supposed hornblende), if not used in the formation of the
chlorite, would have, as Weigand suggests, no place. In addition
to this, however, the difficulty in the supposed chemical changes of
the disappearance of silica or accession of magnesia is not touched.
Thus, if we assume the quantity of the most persistent substance,
alumina, to be represented by unity, and take the amounts of the
other components as ratios to that in the amphibolite and in the
bulk serpentine’ respectively, we find how very different is the
composition of the supposed original rock and of that into which it is
stated to change. Thus

the silica would be 27-305 : 1 instead of 6°898 :1;
the magnesia ,, 26°623:1 bi 3°902 : 1.4

2 Since it was shown that the chlorite contained lime, then the original mica
should have been a variety which included that constituent. The amount of
lime, however, in the bulk analysis is slightly greater than would be explained
by the quantity in the chlorite. The presence of perofskite might partly
account for this.

2 Quart. Journ. Geol. Soc. vol. xlvii. (1891) p. 466.

3 That this serpentine represents a normal average specimen may be seen by
combining the analyses of the chlorite and of dissolved serpentine on the
estimate that the chlorite forms roughly about ~, or j; of the bulk of the rock,
when a composition is obtained very near that of the bulk analysis.

4 Or compare the calculation given by Prof. Bonney, Geol. Mag. 1887, p. 67,
and note.

Vol. 53.| ORIGIN OF THE RAUENTHAL SERPENTINE. 259

Although it may not be possible to show the fate of the surplus
silica,’ this does not offer much difficulty if only a small amount of
hornblende has been really transformed. In all cases of serpentini-
zation such a change takes place, but is not evident microscopically ;
and in the case of sundry hemithrenes, where there is distinct
evidence of serpentine having formed from malacolite, no visible
silica can be detected.

We conclude then, in regard to the Rauenthal rock, that serpentini-
zation occurs of occasional hornblende-crystals, and of some enstatite,
but that the greater part is to be attributed to the serpentinization
of an olivine-rock, and that the probable origin of the chlorite is a
modification of a mica.

(7) Structural Characters.

The structural characteristics of the mass suggest some further
explanations. With regard to the amphibolite, Herr Weigand has
described its peculiar foliated appearance. If the hypothesis put
forward by him could not be accepted, there yet seemed a possibility
that the rock might represent parts of the adjacent gneiss in contact
with an igneous mass and modified by it. Indeed, my first exami-
nation of the locality suggested the possibility that one rock might
have been included and partially melted down by an intruding
magma, as has been proved to be the case in parts of Cornwall °;
but the idea was clearly negatived by further evidence in the field
and afterwards by that obtained by the microscope.

The amphibolite of the Rauenthal (with a foliated appearance)
forms actual streaks or layers (sometimes a few inches thick) within
the serpentine. Under the microscope these are seen to consist
chiefly of characteristic and unaltered hornblende. But at parts of
the serpentine itself the thin dull-greenish streaks: (3 inch thick)
previously mentioned are composed of similar hornblende, which,
however, is partially serpentinized. The chlorite-flakes usually form
thin layers, which help to give a platy habit to the rock—one of
its distinctive characteristics (Pl. XVII. fig. 6). All these structures,
so far as my observations went, have a general parallelism.®

In the different layers, however, streaks of other composition
occur; thus, in an amphibolite-band, we find strings of serpentine
or occasional chlorite, sometimes in fair abundance (see fig. on p. 249
& Pl. XVII. fig. 4). Andthe various minerals are not confined to
special layers. Chlorite occurs, as Weigand states, scattered without
orientation ; the serpentine sometimes has a patchy look, and is
dark green mottled with pale green—owing to an irregular mixing
of serpentinized hornblende. As already stated, enstatite can be

1 Ts it possible that the brownish, somewhat amorphous-looking substance,
found at places, could be opaline in its nature ?

2 Quart. Journ. Geol. Soe. vol. xlvii. (1891) p. 471.

5 This seems to be in a direction roughly parallel with the boundary of the
outcropping serpentine ; but the observations on this point were taken in bad
weather, and must be further tested for confirmation.

260 MISS C. A. RAISIN ON THE NATURE AND [May 1897,

recognized in the serpentine, and augite occurs in one part of the
amphibolite. é

There seems only one possible explanation—since the hypothesis
of a modified gneiss is not alone improbable from a prior: reasons,
but also is contradicted by field evidence and by microscopic
structure—namely, that the serpentine has been derived from a
peridotite, 2. e. from an igneous rock. The interlamination of the
amphibolite, its boundary ‘ not sharply marked off’ (as was described
by Weigand), the ill-defined hornblendic patches and streaks, all
point to gradations from the peridotite to the amphibolite. Similar
variability also is shown in the amount and arrangement of the
chlorite, and in the distribution of enstatite. Thus the evidence
suggests that the original magma was somewhat variable (as often
is the case, especially in magmas of a basic character),’ and that
the rock formed from it was sometimes an olivine-enstatite rock
(saxonite), sometimes a hornblende-peridotite, or a mica-peridotite,
or even a hornblendite.

The parallelism of the structures has, however, to be explained,
and it may be due to the same cause which has developed in many
igneous rocks and complexes a fluidal banding or orientation. The
mica-tlakes would then lie in the direction of the flow, causing a
platiness, possibly afterwards further developed by contraction, and
the hornblende-crystals would exhibit a similar orientation. The
arrangement of the chlorite, and the related platy structure of the
rock, would be very difficult to explain on Weigand’s hypothesis as
to the origin of that mineral. It is impossible to appeal to pressure
as a cause; the whole rock, as shown in both the serpentine and
the amphibolite, evidently is generally unmodified by any such
mechanical force.

At places, rather ill-defined large patches of serpentine and of
amphibolite are found, as if a brecciation had occurred, and the dis-
tinction between the two rocks here and at other places is macro-
scopically so evident that it suggests the possibility of magmas
somewhat different in age. The gradations and intermixing,
however, make it probable that this distinction originated by |
differentiation of a single magma, but whether at a comparatively
late epoch after the intrusion had commenced, or whether earlier,
it does not seem possible to prove. Only at the greater depths,
separation by specific gravity on Soret’s principle might have
acted, causing the less dense part of the magma, which solidified as
amphibolite, to separate from the heavier part; and the fragmental
appearance just mentioned might then be due to a kind of flow-
brecciation. This pseudo-breccia is found in one or two crags
towards the north-western border of the serpentine massif. In
this direction the amphibolite appears to be more developed, not
because it is due to metamorphosis of the gneiss (since ser-
pentinized hornblendic patches and streaks occur, almost to the

1 Of. J. W. Judd, Quart. Journ. Geol. Soc. vol. xli. (1885) pp. 358, 390,
where a peridotite is shown to pass gradually into a picrite or other minor
varieties, and even into gabbro or dolerite.

Volic3.] ORIGIN OF THE RAUENTHAL SERPENTINE. 261

opposite border of the outcrop), but possibly because it formed here
the lighter upper part of the mass, like a kind of scum.

Thus I believe that the structural and mineralogical characters of
the Rauenthal serpentine can all be explained by the intrusion of an
original peridotite-magma* somewhat variable in its composition,
and that they do not require the hypothesis of an origin different
from that which has been proved for most serpentines.

IV. Comparison WITH OTHER SERPENTINES FROM THE VOSGES.

In order to test more fully the views set forth above, I have made
a Study of other serpentines, both from the Vosges and from more
distant localities. So far as concerns the former, before comparing
them with the Rauenthal serpentine, we must add certain types of
rock and certain mineral constituents to those described by Herr
Weigand; and some corrections must be made in the proportions
which he assigns to the constituents.

1. Thus there is far more variation in each mass than he has
observed, and at the same time far more similarity between those
which he has taken as different masses. The Starkenbach and
Bonhomme serpentines are described as originating from separate
magmas, but parts of the two rocks are almost identical. The
Starkenbach mass is stated to be a bronzite-serpentine having olivine
sometimes up to as much as 25 per cent.* While one of my
Specimens agrees fairly well with this description, the proportions
estimated by rough calculation in the slices of three others seem to
give—in two of them, about 80 per cent. and 90 per cent. of olivine
respectively, in another about 50 per cent. of augite. The Bonhomme
mass is described as an olivine-serpentine, and therefore distinct
from that of Starkenbach. As we have just seen, parts of the latter,
however, are formed mainly of olivine, and it is acknowledged that
in the former variations exist. Weigand speaks of ‘only a few
small flakes of hornblende’ being accessory * (besides picotite,
modified ‘garnets, noble erpentine, and iron oxide), but this
hardly describes parts of the rock which include about 60 per cent.
of augite and hornblende.

2. The most important point, however, is the distinct resemblance
of the Starkenbach and the Bonhomme masses to the Rauenthal
rock, since both these are admitted by Weigand to be derived from
forms of peridotite,—the first from a bronzite, and the second from
an olivine-rock.’

(i) Thus one slice from Starkenbach is from a rock completely
serpentinized, evidently formed from two minerals—enstatite and
olivine. The enstatite has the appearance described by Weigand,°
but the major part of the slide consists of serpentine undoubtedly

1 The absence of intrusive ‘dykes or branching veins’ seems to be in harmony
with the ‘ usual habit of peridotites and serpentines.’ See T. G. Bonney, Quart.
Journ. Geol. Soc. vol. lii. (1896) p. 29.

2 B. Weigand, op. cit. p. 196. 3 Ibid. p, 194.

4 Ind. p. 191. ° Ibid. pp. 191, 196. 8 Ibid. p. 193.

262 MISS C. A. RAISIN ON THE NATURE AND [May 1897,

having the meshwork-structure of a mass developed from olivine,
and, except in the presence of rather more magnetite than occurs
in most but not in all of the Rauenthal rock, this has a similarity,
we might say an identity, with the parts of that serpentine which
may be claimed as showing an olivine structure. In many kernels
of the original mineral a border occurs, of slender rutile-rods with
a radial arrangement as I have described it above in a Rauenthal
serpentine (p. 253). In another slice from Starkenbach we can
trace all stages in the alteration. In the completely altered rock,
strings of serpentine, often straight, not seldom form a rudely
rectangular network or even occasionally cross at angles of nearly
120°. In other words, it has the characters of most of the Rauenthal
serpentine, but here is associated with distinct remains of olivine.
Serpentinized enstatite and picotite occur, as described ; a colourless
hornblende and a white augite are also present.

(ii) The strongest resemblance, however, can be found in parts
of the mass which is claimed by Herr Weigand as an olivine-serpen-
tine—that at Bonhomme. ‘This rock shows much variation, includes
sometimes the patches described as modified garnets,! sometimes
picotite in exceptional abundance, sometimes serpentinized enstatite
or clustered augite or hornblende. Most of the serpentine has been
derived from olivine, but at parts well-cleaved crystals of hornblende
more or less serpentinized occur, which, like the chlorite or the
hornblende within the Rauenthal rock, are ‘grouped in layers’ or
‘scattered quite irregularly.’ One slice which consists mainly of
olivine (some kernels still remaining unchanged), but includes
several crystals of partially altered hornblende, seems to give a
perfect representation of what parts of the Rauenthal rock should
have been at an earlier stage (Pl. XVII. fig. 1).

This mass it was which first furnished evidence, conclusive in
my opinion, of the origin of the peculiar chlorite already discussed.
Glittering silvery flakes occur on certain specimens,” and microscopic
investigation proved their identity with the chlorite; but in the
same slide the mineral could be traced associated with, and evidently
developed from, a variety of mica. This is pale brownish, with.
pleochroism from almost colourless to that tint, and resembles the
form of phlogopite seen in the Kimberley peridotite.* A specimen
from among tumbled blocks, which are almost in situ by the road
just south of the col, has mica occurring in larger flakes, also large
enstatite-crystals, and a bright green apparently chloritic mineral.
The specimen is practically identical with a rock from Portsoy.’

1 B. Weigand, op. cit. p. 190. The interesting structure of these must be
left for future investigation, since it has no direct bearing on the question here
under consideration.

2 The chlorite is noticed by Delesse, who states that it differs from the variety
formed from garnet in the Zoblitz rock, being less rich in iron: Annales des
Mines, ser. 4, vol. xviii. (1850) p. 327.

3 Geol. Mag. 1895, pp. 497, 498. This mica seems to undergo change to
vaalite or to silvery spangles.

4 For the loan of this and other slides from Portsoy I am indebted to Prof.
Bonney.

Vol. 53.] ORIGIN OF THE RAUVENTHAL SERPENTINE, 263

Thus the most noticeable peculiarity in the Rauenthal serpentine
may be connected with conditions characteristic of other peridotites.

Lastly, in both the Starkenbach and Bonhomme masses, a banding
is well exhibited, being apparently the effect of a flow-structure
similar to that which has developed some characters of the Rauenthal
rock.

V. CoMPARISON WITH SERPENTINES FROM OTHER LOCALITIES.

Other serpentines afford a valuable means of comparison on many
points, and I have to thank Prof. Bonney for the opportunity of
studying the large collection of slides of this rock made by him
during so many years of his work.’

First, as to the accessory minerals: while in some of the Lizard
rocks picotite is well developed, many of them do not contain it;
and even in outcrops of the Vosges (as Herr Weigand shows) it is
found at some parts, while absent at others of the same massif.
It is thus by no means universal as a constituent. Further, the
occurrence in the Rauenthal rock of perofskite and of rutile, similar
in character to that in other serpentines, has now been shown.?

The iron oxide visible in the slides in most of the Rauenthal
specimens is small in amount, and this fact is associated with the
character of the serpentine next to be considered, but the chemical
analyses prove that a fair quantity of iron oxide is present. Much
of it is connected with the chlorite, although some occurs in minute
form in the serpentine.

The meshwork-structure of serpentine, now so well known, is not
always universal (even in the rocks of one area) ; although no doubt
would be entertained as to their origin from peridotites. The valu-
able article of F. Becke on the Stubachthal has recently expressed
this conclusion.’ In the Rauenthal rock, however, a serpentinous
network can be recognized generally, and, although it is usually
somewhat regular in form, a similar rectangular net was traceable
in the great majority of the slices from the Lizard rocks. No
argument seemed more impressive than this likeness in the essential
structure * shown throughout so large a collection of specimens,

1 The collections of slides which I examined included 43 specimens from 18
localities at the Lizard; others from Portsoy, Zoblitz, the Rauenthal, the
Harz, Aberdeenshire, and New Brunswick.

> It is interesting to recall the fact that the mica-peridotite dyke of Kentucky
is described by J. S. Diller as composed ‘essentially of biotite, serpentine, and
perofskite,’ with small amounts of secondary minerals: Am. Journ. Sci. ser. 3,
vol. xliv. (1892) p. 287.

3 « A distinct serpentine occurs which is derived from a typical olivine-rock,
and in which nevertheless the meshwork-structure is completely wanting in
the changed parts,’ Olivinfels & Antigorit-Serpentin, Min. & Petr. Mitth. 1894,

ae lis
Of the three types of serpentine enumerated by Mr. Teall (‘ Brit. Petrogr.’
1888, p. 115) the study of the Rauenthal rock seems to take away one chief
example of the second, and the work of Herr Becke to lead to an important
subtraction from the third.

+ A likeness which was previously indicated by Prof. Bonney, Geol. Mag.
1887, p. 68.

264 MISS C. A. RAISIN ON THE NATURE AND [May 1897,

since it may be presumed that no one would maintain a horn-
blendic origin for the Lizard serpentine.’

A colourless hornblende is characteristic of various masses of
serpentine. At places (as, for example, Portsoy), a peculiar amphi-
bolite occurs which shows an almost exact similarity in microscopic
structure to that of the Rauenthal; and in rocks from Portsoy and
the Lizard the appearance of hornblende undergoing serpentiniza-
tion is exactly represented. The garnetiferous serpentine from
Zoblitz also may be closely compared in the character of the
serpentinized hornblende, except that in one slide I found that the
amoant is far greater than is usual in the Rauenthal serpentine ;
but in others the hornblende-serpentine formed the smaller part of
the rock, and the account given by Lemberg * describes the serpen-
tine as originating from an olivine-rock containing some hornblende
and garnets or their chlorite-pseudomorphs. Thus, in the first two
characteristics, it may be compared with that of the Rauenthal.

The characteristic chlorite is not peculiar to the Rauenthal
serpentine, for it was identified by Prof. Bonney in slices from the
Lizard. Even there it suggested a possible bleaching of biotite.’
On examining these slices, I at once recognized the mineral as
similar to that in the Rauenthal mass. It is represented also at
Portsoy.

Mica has generally been described, occurring in serpentines or
peridotites, as akin to phlogopite, and this seems to be the nature of
the mineral from which the chlorite originated in the Rauenthal
rock. ‘Thus an interesting comparison may be made with the few
and rare mica-peridotites which have been described.*

The chemical composition of the Rauenthal and of other serpentines
shows so great a resemblance that it would be difficult to suppose
that they had originated by alteration of two totally different rocks.
One of the Lizard serpentines most closely related seems to be
that from near Cadgwith, of dark or black colour. The microscope-
slide also shows marked similarity, and exhibits chlorite as well
as some hornblende. It may be convenient to place side by side the
analyses of the two rocks, and of two others, which are interesting

for comparison :—

1 Residual olivine has been described at several localities, such as Coverack,
Carn Sparnack, south of Kennacka, and others on the western coast.

2 Zeitschr. d. Deutsch. geol. Gesellsch. vol. xxvii. (1875) p. 531.

3 Quart. Journ. Geol. Soc. vol. xlvii. (1891) pp. 473, 474. Cf. slices from
near Cadgwith, Porthalla, and other places.

4 The clustered chlorite in some specimens apparently has a similarity to the
occurrence of mica in the mica-peridotite from Kentucky described by J. 8.
Diller, where the mica ‘occurs in round or oblong patches.’ It is, however,
more abundant than it would have been in the Rauenthal rock and ‘forms the
groundwork.’ Within the scales is scattered some serpentine. ‘The biotite is
occasionally altered to chlorite, Am. Journ. Sci. ser. 3, vol. xliv. (1892) p. 287.
The similar dyke near Ithaca, N.Y., is described by J. F. Kemp as occurring
with ‘the characteristic reddish biotite of the peridotites, Am. Journ. Sci.
ser. 3, vol, xlii. (1891) p. 411. Cf. also a dyke in Central New York, 72d. vol.
xliii. (1892) pp. 822-327, C. H. Smyth Jr.; and the De Witt dyke, idzd. vol.
xlix. (1895) p. 458, N. H. Darton & J. F. Kemp.

Vol. 53.] ORIGIN OF THE RAUENTHAL SERPENTINE. 265

: The Rauenthal serpentine ; the bulk analysis given by Herr Weigand."

: The matrix of the dark serpentine from near Cadgwith.?

: Dark oil-green serpentine from Porthalla.?

: A mica-peridotite from Kentucky, described by J. S. Diller.* In this the
high percentage of lime and alumina, and the low proportion of magnesia,
can be accounted for by the large quantity of mica present.

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Hate ei a als, awe) talk. } i ae ie O85
; ‘70 :

HON umes nx, 13089 12°35 \ er 0
TE, Te nate epi Seim a anlens elidel St i ataiatallia tied 0:89
eee eet eatat Pp csceee, 9 gases ol | aukeee 0:05
ee ee eee eat Bae NEAR > OLEAIS ?
CORES a ae Pe eee ere ES Be: coe 0:43
il, eon ae 0-41
tugol in HC! ...... ee 1°37

Matas Bias Ree 100°58 100-00 99°86

Specific gravities...... 2587 2°56

The significance of the occurrence of bastite as a point of likeness
is so obvious that it need only be mentioned.

The variation in many masses is an important means of correlation,
since it is from this character, or rather from the overlooking of it,
that some difficulties in interpretation have arisen.*

The structural characteristics afford a means of comparison with
other serpentines. For instance, in the Lizard rocks, the occurrence
of a structure both on the eastern and the western coast, which
resembles a slight foliation, has been noticed, and occasionally there
is also banding, especially at Porthalla.°

1 Op. cit. p. 199.

2 Quart. Journ. Geel. Soc. vol. xlvii. (1891) p. 466. Analysis v., by
Mr. Hudleston.

8 Jbid., analysis vit., by Mr. Collins.

4 Am. Journ. Sci. ser. 3, vol. xliv. (1892) p. 288.

° The variability of Lizard serpentines is well shown by the tabular
summary, Quart. Journ. Geol. Soe. vol. xlvii. (1891) p. 467.

§ Quart. Journ. Geol. Soc. vol. xlvii. (1891) pp. 470, 472, 474. See also note
on lherzolite written in 1876, quoted on p. 475. A banded specimen which I
brought from Bonhomme is practically identical with that from Porthalla which
is represented in pl. xvi.

A similar structure (fluxional or banded) has been observed in other holo-
crystalline igneous rocks, as in the diorites of Guernsey (Quart. Journ. Geol. Soc.

Q.J.G.8. No. 210. T

266 MISS C. A, RAISIN ON THE NATURE AND [May 1897, |

Thus a serpentine such as may be found at the Lizard exhibits
marked likenesses to that of the Rauenthal. The bastite is similar,
the accessory hornblende, the chlorite (although more common in
the Rauenthal), the general network of the serpentine, the variability
in the composition, and the occasional banding at the Lizard. It
may perhaps be said that in the Rauenthal rock the olivine is a less
ferruginous variety, and the mica richer in iron more common.
But, with such marked likenesses, how could a different origin for
the two masses be at all probable ?

VI. Summary.

The views of Herr Weigand on the Rauenthal serpentine are
briefly as follows :—

That a passage can be traced, from the dark hornblendic bands
of the gneiss (by increase and modification of the hornblende) to
the pale greenish amphibolite, and from the amphibolite (by a
process of alteration) to the serpentine.

That the chemical changes in the latter process can be explained,
if we assume that chlorite is formed mainly from certain constituents
of the hornblende.

That by microscopic examination a hornblendic structure is
shown throughout the serpentine.

Therefore, that the serpentine here is the result of change, not
of an igneous peridotite, as in neighbouring localities, but of part
of the gneissic series.

The evidence opposed to this conclusion may be shortly stated :—

(1) That in the field we can trace no passage from gneiss to the —
peculiar amphibolite.

That no consideration is given by Herr Weigand to the general
difficulty which would be involved by a peculiar and local modifi-
cation of the gneiss such as is to be found nowhere else in the
neighbourhood.

(IL) That the chemical changes of amphibolite to serpentine as
exhibited in his analyses cannot be fully explained; and that the
chlorite seems more probably derived from an original mica.

(III) That on microscopic examination the hornblendic structure
in the serpentine is seen to be limited to certain isolated crystals or
crystalline layers or patches of original hornblende, and that the
greater part of the serpentine appears to be derived from olivine.
That enstatite, a constituent of peridotites, occurs here. That some
iron oxide, minute rutile, and perofskite are also present.

(IV) That apparent gradations in the rock are connected with the
different arrangements of hornblende, chlorite and enstatite. That
this variation (of which the amphibolite may form an extreme case)

vol. xlviii. 1892, p. 135) and the gabbros at the Lizard (<did. vol. xlvii. 1891,
pp. 484490). “ig ‘Brit. Petrogr., J. J. H. Teall, pl. xliii. fig. 2. See also
Report on Rocks of St. Paul’s Island, Renard, Chall. Exped. Narrative, vol. ii.
App. B, fig. 2, pp. 7, 14.

Vol. 53.) ORIGIN OF THE RAUENTHAL SERPENTINE. 267

seems to be due to differentiation of an original magma, in which
fluxion-structures were developed.

(V) Neighbouring serpentines in the Vosges are found to exhibit
closer likeness one to another, greater variation in each mass, and
more marked resemblance to that of the Rauenthal (in mineralogical
composition and structure) than are described by Herr Weigand.
Thus it seems impossible to maintain that the Rauenthal serpentine
is distinct in its origin from these adjacent masses. Yet they are
claimed by him as derived from peridotites (olivine- or enstatite-
rock).

(VI) By comparison with serpentines from many other localities
beyond the Vosges, such a likeness is found that it does not seem
possible to attribute a different origin to the Rauenthal mass. As
Prof. Bonney has said, possibly ‘the white hornblende is rather
exceptionally abundant’! and ‘(as sometimes occurs elsewhere) a
peculiar variety of chlorite is locally developed.’* Otherwise, the
Rauenthal rock resembles in structure, in chemical composition, in
mineral constitution, and even in the variations of its minerals,
certain serpentines from Cornwall, Scotland, and the Continent.

Thus the serpentine of the Rauenthal would be but one of the
varied forms in which that rock occurs in the neighbourhood of the
Bressoir. It seems to have developed there from a not very pure
or an ill-mixed magma, which was sometimes an olivine-rock (a
dunite), sometimes either an olivine-enstatite rock (saxonite) or an
augite-olivine or a hornblende-olivine, or, as I believe, a mica-
peridotite. These variations may extend over fairly large areas or
may be closely associated as thin, probably fluxional bands, within
the same mass. As, then, I cannot admit the Rauenthal serpentine
to be anything but an altered peridotite, I should not expect that
serpentines in other gneissic regions * were unusual in their origin.

EXPLANATION OF PLATES.
‘ Prats XVI. (Map).

The serpentine-bosses are marked diagrammatically, but the patches give a
rough idea of the relative size of the different crags. The boundary of the
outcrop cannot be traced with exactness, but indications are given by fragments
of rock and by the contour of the ground; thus the curving line at the south-west
is drawn roughly along the direction where a rather sudden steepening in the
slope seemed to imply a change of rock. The minerals (chlorite, enstatite,
hornblende) are indicated in the serpentine at places on the plan, as examples
of the variation in its composition ; but no attempt has been made to show
exhaustively where these minerals occur.

The blocks and fragments of rocks are intended only to show general
position.

Paths and roads are mapped from examination of the area by the Author.

* Not without parallels for comparison: for example, Zéblitz, Portsoy.

? Geol. Mag. 1887, p. 69. —

8 B. Weigand, op. cit. p. 203 ‘Es steht mit Sicherheit zu erwarten, dass
Serpentine abnlicher Entstehung sich in Gneissgebieten in Menge finden
werden.’

T2

268 | THE RAUENTHAL SERPENTINE. [May 1897, |

Puate XVII.
All the figures are x 20. Figs. 2-6 are of Rauenthal serpentine.

Fig. 1. A slice from the Bonhomme serpentine (which is admitted to be an
olivine-serpentine), to illustrate the similarity to the Rauenthal rock.
The drawing shows accessory hornblende-crystals, serpentinized,
among olivine-serpentine as in fig. 2 from the Rauenthal. The chief
differences are, in the Bonhomme rock, the presence of picotite
(represented together with opacite by dark spots in the drawing) and
the occurrence of some residual unchanged olivine.

Fig. 2. Crystals of accessory hornblende, serpentinized, but still exhibiting
characteristic cleavage, within a mass of olivine-serpentine. Iron
oxide, with amount and arrangement as usual, occurs in the slide.
Serpentinized enstatite and chlorite are also present, but are not
shown in the drawing. (The darker tint of this figure, as compared
with fig. 1, is due to the slice of the rock being much thicker.)

Fig 3. Chlorite accompanying and enclosed within olivine-serpentine, associated _
with partly-changed hornblende. Some of the chlorite is in a tran-
sitional condition, evidently forming from mica. Crystalline grains
of iron oxide are present.

Fig 4. ‘ Amphibolite’ consisting of hornblende, mostly unaltered, sometimes
in idiomorphic crystals, associated with well-developed chlorite.
(Band in Rauenthal serpentine.)

Fig. 5. Interstreaking of greenish olivine-serpentine and colourless well-cleaved
hornblende (‘amphibolite’). Iron oxide is present. Structure
probably fluxional.

Fig. 6. Olivine-serpentine, with the usual meshwork-structure. Many of the
fine dots over the grains represent minute granules of ferrite, probably
hematite ; and a few larger patches of opacite and ferrite are shown
in the drawing. Chlorite occurs in parallel or orientated flakes, but
no hornblende is associated with it.

DIscussIon.

Prof. Jupp called attention to the fact that the relations of the
serpentine of the Rauenthal to the adjacent granites and gneisses,
as described by the Author of the paper, are strikingly like those of
the peridotites and serpentines of North Carolina and Georgia to the
granites and gneisses of that area.

Mr. Ruttey said that the rocks included within the area described
would unquestionably yield serpentines varying considerably in
character. One of these rocks was stated to be amphibolite, and,
although the nature of rocks bearing this name is open to question,
he thought that in certain cases amphibolites were eruptive rocks.
When the hornblende of an amphibolite was converted into ser-
pentine, it would be interesting to know what became of the other
constituents. He appreciated the straightforward way in which
only actual exposures were represented on the map, and believed
that the paper, when printed in full, would be a valuable addition
to the literature relating to serpentines and their origin.

Prof. Bonnzy stated that the mode in which the serpentine
occurred corresponded with what could be seen in several localities.
The question of the connexion of the foliation of the serpentine
with pressure had always been present to the mind of the Authoress,
but no connexion had been proved. He agreed with Mr. Rutley
that amphibolite was generally an igneous rock. There was a
difficulty in accounting for the missing silica; but the fact of the
change of certain pyroxenes into serpentine was indubitable. This
rock, however, had originated from a peridotite.

Quart. Journ. Geol. Soc. Vol, LIII. Pl. XVI.

---+--- Sasha acta
= —

me Sn eer ee
Pee yn) | ee

\ : \\
\W° Gneiss 1
\\efragments "

SKETCH-MAP, To SHEW
THE APPROXIMATE POSITION
AND CHARACTER
OF THE

RAUENTHAL SERPENTINE.

: " =
3 i) ~
H ies | tS)
Bo a
a nn ) a
5 eS “
: ee :
: " a
ia Mae [Length of Serpentine outcrop from N.
: i a) = i
: i to S. very roughly about 14 mile |
\ [|] Senpentine
M
Ix
Hy 1@0eee Serpentine-blocks or fragments
i Layer of Amphibolite
Ny Hornblendic streak or ;
ks i ee Pee. Chlorite [ patch in the
Se \ ee eee PEST RLILE Serpentine
i NER O97 / My Oe gd sees _ Chlorite and Enstatite
z = HELLA... Gnetss
S

c000000 Gneiss-fragments or blocks.

tyivyp *
rey ell. Granite

XxXxxxx Granite-fragments or blocks.

Probable boundary of Serpentine
seeseeeess Doundary less certain.

Stream

The ground is mostly covered
qith wood.

el

gnnysorvrs
wots PPO

Quart. Journ. Geol. Soc. Vol, LI. Pl. XVI.

° Small
H 5
\\0 Gneiss
\efragments

Serpentine- blocks
scattered along the stream

This Serpentine is a
broken amass, but is al-
niost certainly in situ

fragments along path

Granite -

Serpentine-blocks fallen

Granite -fragments
from above down steep slope

along path

Farther in this direction are Granite
and Gneiss in situ,

SKETCH-MAP, To sHEW
THE APPROXIMATE POSITION
AND CHARACTER
OF THE

RAUENTHAL SERPENTINE.

<7)

*

[Length of Serpentine outcrop from N.
to S. very roughlyaabout 14 mile]
[1 Serpentine

ja cece Serpentine-blocks or fragnents

au Layer of Amphibolite
Hornblendic streak or

== -. Chlorite [Aatch in the
Re . Enstatite Serpentine
serovars - Chlorite and Enstatite)

BA Gneiss

c0c0000 Gyeiss-fragments or blocks.
tytyy *
rye)... Granite

Xxxxx Granite-fragments or blocks.

Probable boundary of Serpentine

steceeeees Boundary less certain.
Koad

Path

~~ Stream

The ground is mostly covered
quith wood.

Quart. deurn. Geol soc Vol. LIN. PL XVIl,

25

Mintern Bros.imp.

FA Michael del.etlith .

Ee poo NEAT, SERPENTINE -

(Figs. Zak.)

Wori53.| THE RED ROCKS NEAR BUNMAHON. 269

21. The Rev Rocks near BenMaHon on the Coast of Co. WatERForD.
By F. R. Cowper Reep, Esq., M.A., F.G.8. (Read March 10th,
1897.)

ConTENTS.
Page
PPT NU CKCUTECLTOUE. eo site x anrccctecp a Sa Sa eee aR ee ae 269
ie Genera) Structure of the District (3.2 2s0.cs.2-.ccc.cceclontwgaveces 270
III. Mode of Occurrence and Relations of the Red Rocks of
Binmahonand! Neiwhbourhoody) g.0s22e42.dests-de ee ee 272
iW Summiary of the! Myid ence sce asssioclasesdals..at denecanengadaaeseaes 282
V. Probable Explanation of the Mode of Occurrence of the Red
EGTA A Pipa ES eA Le Meh ol i MA alata Bl 282

L. Inrropuctrron.

THRs are a few patches of red sandstone, shale, and conglomerate
on the coast of Co, Waterford whose age has been the subject
of much divergence of opinion, owing to the obscurity of their
stratigraphical relations and isolated positions. A recent visit
which I paid to these parts enabled me to collect evidence which
seems to my mind to settle their age conclusively.

The earliest description of these rocks with which I am acquainted
was published by Mr. J. Hodgson Holdsworth! in 1833. He main-
tained the view that they were of the same age as the ‘ great con-
glomerate-formation ’ of the Monovoulagh or Comeragh Mountains,
which he rightly ascribed to the Old Red Sandstone. He pointed
out also the tact that they rest unconformably on the ‘ Silurian’
rocks.

‘The next mention of these beds is by Mr. T. Weaver * in 1835,
when he described a gradual passage from the greenstone rocks into
the red sandstone ‘through the medium of a compound con-
glomerate’ of greenstone with red sandstone-fragments and of red
sandstone with greenstone-fragments. Thus he apparently favoured
the view of their ‘ Silurian’ age.

Mr. J. Beete Jukes* in 1852 put forward the view that these
patches were blocks of Old Red Sandstone let into the ‘Silurian’
rocks of the coast by complicated faults.

In 1860 Messrs. W. B. Brownrigg and Theo. Cooke,’ in a brief
description of the coast, accepted the view that these patches are
faulted masses of Old Red Sandstone.

In the Geological Survey memoir of this district’ Mr. G. V. Du
Noyer rejected the idea of the Old Red Sandstone age of these red
sandstones and conglomerates, aud maintained that there are two

' ¢On the Geology of the District of the Knockmahon Mines in the County
of Waterford, Journ. Geol. Soc. Dublin, vol. i. (1833) p. 85.

* *On the Geological Relations as the South of Ireland,’ Trans, Geol. Soc.
Lond. ser. 2, vol. v. pt. i. (1837) p

3 «Sketch of the Geology of Be Casey of Waterford,’ Journ. Geol. Soc.
Dublin, vol. v. (1852) p. 147.

4 Journ. Geol. Soe. Dublin, vol. ix. (1860) p. 8.

° Explan. Sheets 167, 168, 178, and 179, Geol, Sury. Ireland (1865), p. 10.

270 MR. F. R. COWPER REED ON THE RED ROCKS [May 1897,

groups of these beds ‘ clearly interstratified with the Lower Stlurian ’
rocks and folded with them.

Mr. Kinahan,! however, in 1878, pointed out that they lay
unconformably on the ‘ Cambro-Silurian ’ rocks, and ascribed them
with some hesitation to the ‘ Lower Carboniferous’? (=Old Red
Sandstone),

The same writer in 1887 ° speaks of these red beds as lying on
or partly in the Ordovician, and says that they ‘must be either of
Silurian or Devonian age, probably the latter—that is, small
outliers of the Comeragh conglomerates.’ In 1889 he writes ® of
the Knockmahon conglomerate lying unconformably on the Ordo-
vician, but observes that farther west the red beds appear as isolated
masses in the Ordovician.

Sir Archibald Geikie, in his Presidential Address to the Geological
Society * in 1891, hesitated to express a decided opinion, but seemed
to incline to the view that they were not of Lower Silurian age.

II. GenEeRAL SrructuRE oF THE Disrrict.

If we first glance at the characters and distribution of the
undoubted Lower Silurian and Old Red Sandstone rocks, and at the
general structure of the district, we shall be in a better position to
attack the problem.

The Lower Silurian (Ordovician) is represented in this part of
Ireland by a great assemblage of igneous rocks, together with
sedimentary beds comprising black, grey, greenish, and buff slates
and mudstones, and a few thin limestones. ‘The igneous rocks
largely preponderate, and consist of contemporaneous lavas, ashes,
and agglomerates pierced by intrusive sheets, dykes, and irregular
masses, and occasionally by breccia-filled ‘pipes,’ belonging to
several more or less distinct periods of irruption.

The sedimentary members of this system nowhere assume in this
district the character of red sandstones, etc., 1f we except for the
moment these disputed patches on the coast.’ Primd facie, therefore,
we might well hesitate to include these isolated masses in the
Ordovician. If they be really interbedded with the Ordovician Series,
we might reasonably expect that deposits possessing such well-marked
and distinctive characters and so great a thickness would give
indications of their presence elsewhere, especially as the Ordovician
strata of the district seem to be repeated by a series of folds; but
such is not the case, for nowhere else in the county do we
meet with red rocks which can be ascribed by anyone to any for-
mation but the Old Red Sandstone.

The Old Red Sandstone of the county itself rests everywhere

1 «Geology of Ireland,’ 1878, p. 28.

2 Sci. Proc. Roy. Dubl. Soc. vol. v. (1887) p. 611.

3 Ihid. vol. vi. (1889) p. 283.

4 Quart. Journ. Geol. Soc. vol. xlvii. (1891) Proc. p. 158.

5 Red conglomerates of a similar character are said to appear in the Lower
Silurian (Ordovician) slates of Tagoat, Co. Wexford, but their relations have
not been clearly described, and I have been unable to visit the spot.

Vol. 53.] NEAR BUNMAHON, CO. WATERFORD. 271

unconformably on the older rocks. Its basal portion varies in
character, but is always either a breccia of fragments of the under-
lying Ordovician rocks, as at Dunmore,’ or a series of conglomerates
consisting of rounded or subangular pebbles of variously-coloured
grits and white vein-quartz.

In the eastern corner of the county the sea-cliffs from Knocka-
veelish Head round to Brownstown Head are formed of red sandstone
and conglomerates with the basal breccia about 200 feet thick, near
Dunmore. The total thickness of the beds here is about 400 feet.
In this district the strata are almost horizontal, the dip being at
Dunmore only 5° S. Along the coast to Brownstown Head the dip
is to the south-east at an average angle of 10°. On the south-eastern
shore of Rinnashark Harbour the dip is to the north-west at about
the same angle, so that an anticlinal axis occurs here, and seems to
be in some way connected with the existence of the promontory of
Brownstown Head, as is more plainly the case with the Kerry
headlands. .

The boundary of the beds then sweeps northward from this point
past Passage, to the north side of the river Suir, then bends round
westward, crosses the river again, and, with a mean dip of 30° N.,
they strike west as a narrow band which expands and rises into the
Comeragh Mountains. ‘These mountains consist in the main of a
broad arch of the Old Red Sandstone beds, dipping steeply to the
north and south, and resting on the upturned edges of the Lower
Paleozoic rocks.?, On the southern side of this anticlinal the Old
Red dips suddenly and steeply at angles of from 60° to 70° beneath
the valley of Dungarvan and Lismore, reaching the coast at Bally-
voyle Head, where a fine section of the tilted beds is exposed and
their unconformable junction with the older rocks plainly seen.
Details of this section are given by Sir R. Griffith * in his paper on
‘The Order of Succession of the Strata of the South of Ireland.’
The beds are here about 2250 feet thick, and the basal portion
consists of ‘alternations of reddish grey and red conglomerates,
reddish grey compact sandstone and dark red slate, the conglomerate
predominating. A good diagrammatic sketch of this section is
given in the Survey Memoir already quoted.’

The thickness of the beds in the Comeragh Mountains is about
3200 feet. Towards the north, south, and east, they are thus seen
to become attenuated. Sir R. Griffith also notes (op. cit.) that
conglomerate forms the base of the Old Red in these mountains, and
in the Cahirconree and Slievemish Mountains of the Dingle penin-
sula of Kerry, and also in the Galtees and Slievenaman Mountains of
Limerick and Tipperary. Thus the presence of conglomerates at the
base seems a feature of the Old Red of the South of Ireland. This
point was emphasized by Mr. John Kelly in 1856,’ and by Prof. Hull

1 Explan. Sheets 167, etc. Geol. Surv. Irel. (1865) p. 13.

2 J. Beete Jukes, Journ. Geol. Soc. Dublin, vol. v. (1852) p. 147.
3 Journ. Geol. Soc. Dublin, vol. iii. (1845) p. 150.

4 Explan. Sheets 167, etc. p. 60, fig. 7.

5 J. Kelly, Journ. Geol. Soc. Dublin, vol. vii. (1856) p. 115.

272 MR, F.R.COWPER REED ON THE RED ROCKS [May 1897,

in 1879.! The former says that in all parts of Ireland the two
prominent characteristics of the formation are (1) the presence of
a thick basal conglomerate of quartz, jasper, and other pebbles, and
(2) its unconformity to the inferior rock.

The basal breccia above mentioned as occurring at Dunmore is a
local phenomenon, and is found again in the county only along a
strip of country about 6 miles in length, extending from the
northern base of the Reeks of Glenpatrick to the glen of the Cool-
namuck stream (Geol. Surv. Mem.).

From this rapid survey of the distribution and characters of the
indisputable Old Red Sandstone of the district, we see that it forms
an incomplete elliptical ring round an irregularly oval area of
Lower Palzozoic rocks. Remembering the steep dips of the Old
Red Sandstone off this central area to the north and south, and
its lesser dips to the east and west, we recognize that we have
to do with the remains of a denuded elongated dome. The incom-
pleteness of the ring on the south between Ballyvoyle Head and
Brownstown Head is due mainly to the fact that the southern limb
of the dome is now concealed by the waters of the sea, as Jukes”
long ago pointed out; but supposing this ring is as irregular on this
side as on the northern, and the trend of the beds as variable, owing
to minor folds and disturbances, we might not unreasonably expect
to find some traces of it along the present line of coast. Such
indeed I believe to be the case, and I hold that the patches of red
rocks at Bunmahon and in the neighbourhood are fragments of this
distorted and dislocated ring. Jukes (op. cit.) originally held this
view, but subsequently abandoned it, and in the Survey Memoir,
together with Du Noyer, put forward the opinion that the red rocks
here were of ‘ Lower Silurian’ age, as already stated.

III. Mops or OccuRRENCE AND RELATIONS OF THE Rep Rocks oF
BuNMAHON AND NEIGHBOURHOOD.

The most westerly exposure of these disputed red rocks occurs in
the bay of Ballydouane West, immediately east of Killelton Bay
and stream, and, so far as I know, has not been noticed previously
by any writer on these rocks. Immediately to the east of the steep
zigzag path, winding down the cliffs to the beach in this bay, is seen a
rib of red shaly sandstone halfway up the cliff-face. The relations
of it to the other rocks are obscured by the ground being partly
overgrown and by several landslips, but a careful investigation of
the lines of junction shows that the red sandstone dips into the cliff
in a north-westerly direction, and rests unconformably upon the
igneous rocks which form the lower part of the cliffs. There is
also a thin layer of coarse angular breccia at the base of the red
sandstone, composed of fragments of the underlying felsites, diabases,

1 Quart. Journ. Geol. Soc. vol. xxxv. (1879) p. 719.
? Journ. Geol. Soc. Dublin, vol. v. (1852) p. 147.

a

Vol. 53.] NEAR BUNMAHON, CO. WATERFORD. 273

etc. (see fig. 1). Not only do none of these igneous rocks penetrate
the red beds, but they show signs that they were tilted, faulted,
and crushed along certain planes, as well as eroded before the sand-
stone was deposited on their edges. A more complete example of
unconformity it would be hard to find. A sheet of a very con-
spicuous felspar-porphyry, with large pink felspar-crystals, is seen
high up in the cliffs some 20 or 30 yards west of the red rib, and
seems to run directly towards the latter. A grass-covered steep
slope hides the actual junction, but a line of fault is certainly
suggested by the abrupt termination of the felspar-porphyry within

Fig. 1.—Section in cliff at E. end of Ballydouane West Bay.

Ss
SSS

—s
i=

ais

ee icine ee ae
mee aioe Oye)
Sens

[Height of section = about 40 feet. |

A= Dark greenish, coarse, cleaved | R.S.C.= Red sandstones with basal

ash. conglomerate of diabases,
B= Whitish felsite, fine ash, and dolerites, etc., resting un-
breccia filling old neck. conformably upon the eroded
C = Greenish-grey dolerite. edges of C.
D = Crushed dark green diabase. FF = Faults.

a few yards of the red beds. There is no evidence of the basal
layer of the red sandstone being a friction-breccia, since the sand-
stones and fragments in the breccias show no signs of crushing or
shattering. There is moreover no sign of alteration or disturbance of

274 MR. F. R, COWPER REED ON THE RED ROCKS [May 1897,

these beds by the intrusion of any igneous rock. The sandstone is
quite similar in lithological characters to many beds in the un-
doubted Old Red Sandstone around Waterford; and the basal breccia
may be compared with that of Dunmore.

The vertical line of junction of the red beds with the igneous
rocks on the east is obscure, for the adjacent rocks are stained red
by the washing down of the shaly material; small slips also have
taken place which are now grass-grown, and a spring here breaks
out. There is, however, everything to suggest a fault on this side
too, by the position and characters of the igneous rocks seen beyond
this talus and grass.

The next patch is in the large Ballydouane Bay, and is the one
described with more or less minuteness by all the writers on these
red rocks of the coast. Beginning at the western corner of the bay,
west of the road leading down to the beach, we find the low cliffs—
not more than 40 feet high at this point—composed of a curious
banded rock (ophiolite of Kinahan), much resembling serpentine in
appearance, but containing fossils, dipping most distinctly 60° N.N.W.
—that is, into the face of the chff. On the east, separated from
these banded rocks by
a grass-grown talus Fig, 2.—Ground-plan of foreshore, W. side

slope, a few yards of Ballydowane Bay.
wide, we find red and

yellow sandstones with
thin but frequent bands
of fine conglomerate,
made up of white
quartz and other peb-
bles, dipping 30° N.E.
These form the low
cliffs. On the foreshore
we see these sand-
stones ending abruptly
against the serpen-
tinous bedded rocks
along a line of fault ,

which most clearly F.S. = Fossiliferous banded ‘ ophiolite,’ dipping

N.N.W. at 60°.
shows the two rocks R.S.C. = Red sandstones with thin bands of fine
in contact (see plan,

quartz-conglomerates, dipping N.H. at
fis) 19))) Thins the 30°. 4

western boundary of F = Fault.

the red beds of Bally-

douane Bay is a line of fault. An isolated pyramidal mass of the
red sandstones and conglomerates stands in front of the cliffs at this
point, a few yards west of the gap occupied by the stream and
road. ‘This mass shows the beds dipping N.E. at 45°.

There is thus absolutely no evidence here that the red rocks are
interbedded with the neighbouring strata, and I cannot understand
the succession of beds which is tabulated in the Survey Memoir as
occurring on the western side of Ballydouane Bay. Certainly

‘=

Vol. 53.] NEAR BUNMAHON, CO. WATERFORD. 275

what is now visible does not at all correspond to the description
there given.

At the gap in the cliffs formed by the Ballydouane stream we
find the same red sandstones and conglomerates composing both
sides of the narrow valley, but the beds are here considerably
shattered and disturbed for a distance of a few yards, and the cliffs
are low, irregular, and confused by landslips. However, a dozen
yards or so to the east of the stream-gap we meet with almost
vertical beds of coarse quartz-conglomerates, which, as we follow

Fig. 3.—Section in cliff at N.E. corner of Ballydowane Bay.

SSS

Le

SEN
NNN

SSS
Ss

o>

Oe
Ye
>

ry r,
os Bip
Ne LES eo

pees a ae
Wt SS5 ¢ ie
WA
S

WOW
Miroir }

TN Fy.

SN Vista
ratte
=
xs
Co
“a
4]
y

S = Fine red sandstones in massive beds, dipping N.W. at 80°.
B = Coarse breccia of underlying igneous rocks (Ia, Ib, etc.) in red sandy

matrix 20 feet in thickness, resting unconformably upon the edges of
the igneous rocks I.

Ia = Decomposed greyish dolerite ; b = Dark greenish felsite, intrusive in a.

the cliffs eastward, are found to be underlain by finer conglomerates
and subsidiary alternating beds of red sandstone from 2 to 8
feet thick. The conglomerates form the greater part of the beds,
and are composed of subangular or angular pieces of white vein-
quartz and liver-coloured quartzites. Some of the fragments in the
coarser beds of conglomerate are as much as 8 inches long, and can
scarcely be called pebbles, for they show little sign of rounding or

276 THE RED ROCKS NEAR BUNMAHON. [May 1897.

attrition. The finer conglomerates, however, have their materiais
more rolled, and resemble compacted fine shingle. This series of
beds is from 70 to 80 feet thick, and is finely displayed in the lofty
vertical cliffs at the head of the bay. ‘The dip, which is vertical in
the westernmost portion—z. e. the uppermost beds—becomes 75°—
80° to the N.W. as we walk eastward and pass across the strike
on to the lower beds. ‘The line of cliffs here makes a large angle
with the true strike of the beds.

Suddenly, at the north-eastern corner of the bay, the vertical cliffs
of red sandstone cease, and their place is taken by a steep, grass-grown
cliff formed of a succession of landslips and obscured by much talus.
We at once suspect that this change is caused by the occurrence of
rocks of a different character, and we have not far to look to find our
suspicion confirmed. We find, firstly, that the lowest 20 feet of the
red sandstone and conglomerate-series is composed of a very coarse
breccia of fragments of felsites, greenstones, tuffs, etc., in a matrix
of red sand ; and then at the place where the character of the cliffs
changes we find this breccia resting on the worn edges of the rocks
which have supplied many of the fragments (see fig. 3, p. 275). The
unconformity is most striking, and there is no room for questioning
the complete discordance of the two sets of beds, and the wide interval
of time that must have separated their periods of formation. ‘The
older rocks, including several intrusive masses, present their trun-
cated and broken-up edges to the red series ; none of the intrusions
penetrate the latter, but end abruptly against the basal breccia.
The section of the cliffs of this bay which is figured in the Survey
Memoir (op. cit. p. 58, fig. 6) is very misleading, and contrary to the
evidence now most clearly exposed along the coast. The arrange-
ment and relations of the beds as now seen on the northern side of
the bay are shown in fig. 4.

The inland extension of these red rocks I have not been able to
trace with much accuracy, owing to the nature of the ground, but
there are no superficial indications of their occurrence far inland in
the townland of Ballydouane Kast. If we prolong eastward the line
of fault marked A in fig. 9 (p. 284), we shall see that it must
intersect the strike of the basal breccia so as to enclose a wedge-
shaped block of red beds. A ridge of high ground runs inland
from the central part of the bay in a north-easterly direction and
gives indications that it is formed of the red sandstones and con-
glomerates. This ridge is cut across on the east by the north-and-
south valley of the Cooneenacartan stream.

The cliffs of Ballydouane Bay from its north-eastern corner of
erass-grown talus trend to the south-east, and until nearly halfway
out to Poolatunish Point consist of similar steep, broken, grass-
covered slopes, with the igneous rocks cropping out at their base and
on the foreshore. At this halfway point, however, we see red
sandstones, shales, and conglomerates again composing the cliffs and
dipping to the south-east at 60° in a regular succession of beds.
These rocks appear to be exactly similar to those above described
in another portion of the bay, but are not so accessible. Their

Fig. 4.—Diagrammatic section of cliffs on N. side of Ballydowane Bay.

sop

sepey

soo YY
—
seo’

a
2

ete ed

wo. . aire ~
. e e*!
— .
Stree
peas
SRS Re

\-

oa

[Length of section=about 400 yards. Vertical scale exaggerated. ]
6= Fine red massive sandstones. I

1= Banded fossiliferous ‘ ophiolite.’
2= Red and yellow sandstones, dipping N.H. at 30°. 7 =Coarse breccia, 20 feet thick. | See fig. 3.
3=Slipped and disturbed ground. 8=Tgneous rocks. J

FF= Faults.

4—= Coarse quartz-conglomerates, bedded, nearly vertical.
5= Alternating beds of red sandstones and fine conglomerates.

Fig. 5.—Section in cliffs on E. side of Ballydouane Bay.

[Length of section=about 250 yards. Vertical scale exaggerated. }
| 3=‘ Pale grey felstone’ of St, John’s Island.

1=TIgneous rocks (greenish ash, diabases, felsite-dykes, etc.),
FF= Faults.

2= Red sandstones and shales, dipping 8.E. at 60°.

278 THE RED ROCKS NEAR BUNMAHON. [May 1897.

junction with the talus-covered cliffs of the north-eastern angle of
the bay is somewhat obscured high up by grass and rainwash, but
it appears to be along a plane dipping about 45° S. Close to the
level of the beach the older rocks which occur below this line of
junction are crushed as along a fault-plane, which I take this to be
(see fig.5, p. 277). It does not appear to me to show the characters
of a floor of deposition, like that to the north at the head of the bay
described above.

The extreme point of the headland marked Poolatunish, and
St. John’s Island itself, are not composed of these red beds, but of
some of the older igneous rocks—a ‘ pale grey felstone’ according
to the Survey. I was unable, however, to visit the base of the
cliffs at this point, as it is inaccessible except by boat. Neverthe-
less, it was easy to satisfy myself from the top of the cliffs that
the red beds are abruptly cut off by a fault at this point, and that
a block of the complex and varied older igneous rocks of the coast
is brought against them by this means.

Standing on the extremity of this headland of Poolatunish, and
looking down into the small cove east of it, one can see the cliffs
in its bend composed of the easterly extension of the southern mass
of red beds of Ballydouane Bay, dipping south-east. They are
sharply defined by faults from the igneous rocks, forming the
promontories enclosing the cove. It may be that the fault in the
eastern promontory is merely the continuation of that which cuts
across the point of Poolatunish. At any rate the fault of the
eastern promontory must run in a N.N.E. direction inland, as no
red beds appear in the waterfall cove—Cooneenacartan—on the
eastern side of this promontory. The red beds, however, were found
inland in the townland of Ballynarrid and along the high road to
Bunmahon (as far as the number ‘ 187’ on the 6-inch map) east of
the Cooneenacartan valley. This strip of red rocks appears, there-
fore, to be bounded both on the north and south by faults, the
northern fault being that oblique one seen on the north-eastern
side of Ballydouane Bay, and the southern fault that on Poola-

tunish headland.

The next exposure of red beds is that of Bunmahon Head. They
here form the headland known as Kennedy’s Island, and this mass
has been described by Mr. J. Hodgson Holdsworth.! The cliffs at
this point are vertical, and rise to a height of about 120 feet ; their
edge exhibits in a striking manner the weathering into rectangular
blocks, which is very characteristic of the Old Red Sandstone of
Ireland * and elsewhere.

Viewed from the beach on the western side of the headland, the
red beds are seen to form the whole wall of cliffs extending from
the extreme point to the inner angle of the bay, where a steep
erass slope exists. The red beds consist of the usual red sandstones,
fine conglomerates, and shales, in alternating layers, and dip N.N.W.
at an angle of 80° (see fig.6). The above-mentioned grass slope at

1 Journ. Geol. Soc. Dublin, vol. i. (18338) p. 85.
? Quart. Journ. Geol. Soe. vol. xxxv. (1879) p. 719.

Fig. 6.— Section of W. face of Kennedy’s Island, Bunmahon Heaw

1 = Pink felsite and felsitic agglomerate occupying neck. 3 = Red sandstones, shales, and fine conglomerates, dipping
2 = Greenish ash, seen here and there on the grass slope. N.N.W. at 80°.
2a = Greenish ash forming an isolated pillar on the beach. 4 = ‘Hpidotic felstone’ forming reefs in the sea.
FR = Faults.

280 MR. F. R. COWPER REED ON THE RED ROCKS [May 1897,

the inner angle of the bay hides the actual line of contact of the red
beds with the neighbouring igneous rocks, but within a yard or so
of the disappearance of the red beds we find a coarse so-called ‘ green-
stone-ash’ cropping out here and there. A great pillar of this ash
stands out on the beach, some 20 or 30 yards from the foot of the
slope, as an isolated mass right in the strike of the red beds of the
cliff-wall of the headland, and thus it is evident that a line of fault
separatesthem. A volcanic ‘ neck’ filled with a felsitic agglomerate
and a pink felsite runs up the cliffs almost vertically just on the
west side of the grass slope, and cuts across the ‘ greenstone-ash ’
and a greenish felsite. There are no fragments of the red beds
either in the ‘ greenstone-ash’ or in the felsitic agglomerate of the |
neck, their absence indicating that both these igneous rocks are older
than the red beds.

Fig. 7.—Ground-plan of foreshore on E. side of Kennedy’s Island,
Bunmahon Head.

I = Greenish ash (crushed along line of fault), with intrusive dykes.
R.S8.C. = Red sandstones and conglomerates, with thin red shaly bands.
F = Fault.

Passing round to the eastern side of Kennedy’s Island and
descending again to the beach by the zigzag path at the western
corner of this eastern bay, we find here again the ‘ greenstone-ash ’
in the cliffs in contact with the red beds, and their line of junction
may be most distinctly followed on the foreshore and over the reefs
of rock, where successive beds of red sandstone and conglomerate
are seen to end abruptly against the ‘ greenstone-ash ’ and igneous
masses, which are somewhat crushed and shattered along the con-
tact. This is most clearly another faulted junction, and the line of
dislocation runs out to sea with a slightly sinuous course to the
E.N.E. (see fig. 7). The red beds here, in the cliffs which form the
eastern side of the headland, dip north-west at 75° to 80°. By the

Vol. 53: ] NEAR BUNMAHON, CO. WATERFORD, — 281

side of the zigzag path down the cliffs they are of fine red sandstone
and shale, while nearer the point thin bands of conglomerate come
in, of varying degrees of coarseness, but mostly composed of small
rounded pebbles. ‘Thin layers of shale, 4 to 5 inches thick,
occur in the conglomerates.

The larger pebbles of the conglomerates are subangular or
angular in shape, and only the smaller ones are usually rounded ;
they consist of white and red vein-quartz, liver-coloured quartzite,
and occasionally of felsites and other igneous rocks. The beds at
the point are of coarser conglomerate ; but the reefs and stacks off
the point are composed of a felsitic rock—an ‘epidotic felstone’
according to the Survey Memoir—which is separated by a fault from
the red beds, as at St. John’s Island. Thus again in this locality
we see the complete independence of the red beds and their sharp
demarcation from the surrounding igneous rocks.

Passing along the coast and crossing the Bunmahon River we
fail to find any trace of the red beds until we come to the little bay
below the now deserted engine-house and ore-yard of the Knock-
mahon copper-mines. Here, on the top of the cliffs by the engine-
house, the same type of conglomerate is found as at Kennedy’s
Island, but it is composed of rather larger pebbles and angular frag-
ments. At the mouth of the shaft it is seen to dip to the north-
west at about 45°, and is underlain by fine red sandstone resting
unconformably at the top of the cliff upon an intrusive rock which
forms all the lower portion of the cliff. The junction of the two is
now inaccessible, and I was not able to determine whether it was a.
fault, but no basal breccia was visible, and I am inclined to think
that a fault must exist. The ore-bearing lodes and quartz-veins in
the igneous rocks are seen to end abruptly against the red sandstones
and conglomerates. Mr. Hodgson Holdsworth (op. cit.) states that
on the eastern side of Bunmahon Bay the conglomerate and ‘ red
slate’ underlie the rocks of the coast and run in a N.W.-S.E.
direction, and that they are thought to disrupt or heave the principal
lode. But in one shaft, at a depth of 10 fathoms, the same beds
were pierced as those which ure exposed on Kennedy’s Island.
Kinahan, however, says in his ‘Geology of Ireland’ (p. 28) that
Mr. Hore, of the Bunmahon mines, proved that the red beds and
conglomerates are of later age than the ‘ Cambro-Silurian’ rocks
of Knockmahon, and le unconformably upon them, and that the
lodes in the latter rocks are cut off by the conglomerates. What
is now visible on the cliffs of Knockmahon corroborates this state-
ment. The Geological Survey Memoir ' also mentions the fact that
both the Stage Lode at Knockmahon and the Trawnamoe Lode west
of Bunmahon were lost when the red beds were reached,

1 Explan. Sheets 167, 168, etc. p. 82.

Q.J.G.8. No. 210. u

282 MR. F. R. COWPER REED ON THE RED RocKS’ [May 1897,

LV. SuMMARY OF THE EVIDENCE.

Summing up now the facts gathered from the above-described
sections, the following points become evident :—

(1) The red beds either (a) rest unconformably on the edges of
undoubted Lower Paleozoic rocks and are separated from them by
a striking unconformity, or (6) are faulted against them. When
the line of contact of the two sets of rocks is an unconformity, the
basal layer of the red beds is frequently a breccia of variable thick-
ness, composed of fragments of the underlying rocks. The absence
or thinness of this basal breccia in some spots is of no importance,
as a similar breccia at the base of the acknowledged Old Red
Sandstone of the county occurs only at two widely separated
localities—Dunmore and the base of the Comeraghs.

The strike and dip of the red beds are always widely divergent
from those of the underlying rocks; and whereas the latter have
suffered extensive disturbance and show much crushing, folding,
and faulting in many places, the red beds are comparatively undis-
turbed, and certainly have not shared in the same movements.

The dykes, sheets, and other intrusive rocks penetrating the
Lower Paleozoic strata of the coast have nowhere been found to
pierce the red beds, but are abruptly truncated by them along a line
of erosion.

When faulted junctions occur, the actual lines of dislocation are
generally distinctly visible, and traceable on the ground or in the
face of the cliffs.

(2) The patches of red rocks bear not only the closest resem-
blance to each other in lithological and structural characters, but
also are precisely similar to certain of the undoubted Old Red
Sandstone beds of the county. The mode of jointing and weather-
ing exhibited by the rocks of these patches is also typical of the Old
Red Sandstone.

(3) In no case is there indisputable evidence brought forward
that these patches are really conformably interbedded with the
Lower Paleozoic strata; and beds of similar lithological character
are unknown in clear sections of these older rocks.

V. ProBaBLe EXPLANATION OF THE Mopr oF OccURRENCE
oF THE RED Rocks.

There are no insurmountable or even grave difficulties to be over-
come in attributing these red rocks to the Old Red Sandstone, or in
accounting for the present isolated position of these patches. The
post-Carboniferous folding threw the beds of this area into the well-
known series of east-and-westerly trending folds, many of which are
undoubtedly hidden beneath the sea off the southern coast, while
others are cut across and partially denuded away—as at Dungarvan.
Besides the large folds, the troughs of which now form valleys for
several of the important rivers of this part of Ireland, there are
other minor ones which have had comparatively little effect on the

Vol. 53.] NEAR BUNMAHON, CO. WATERFORD. 283

features of the surface. Not all of these had their axes trending
from east to west. Thus the Brownstown Head anticlinal and
that of the Templetown district in Co. Wexford have an E.N.E.
course, If we suppose a minor sharp fold, with a steeper northern
limb, to have occurred in the Bunmahon district with this course
and to have been dislocated by faults, and blocks of it to have been
let down into the older beds, we shall be able to account for the
occurrence of these patches.
Entering into
details, we see first Fie, 8—Sketch-map of Kennedy’s Island,

that this hypo- Bunmahon Head.
thetical anticline is

cut across almost at
right angles to its
strike by the inlet
of Ballydouane Bay.
The next points to
notice are the faults
that have affected it.
These may roughly
be divided into two
sets—one trending
inageneralW.S. W.-
E.N.E. direction,
and the other run-
ning transversely to
them, with a down- [Scale: 12 inches=1 mile. ]

throw to the east.

In the accompanying 1=Greenish ash, diabase, etc. 1 a=Pillar of greenish

sketch-maps (figs. 8 2a

& 9) the first set 2=Felsitic neck. 38=Red sandstones, shales, and
are marked A, B, C, conglomerates.

etc., and the trans- 4=Epidotic felstones. De, DE= Faults.

verse set a, b,c, ete.

Fault A occurs on the north side of Ballydouane Fay, a short
distance inland; its exact position is imdeterminable, but its
influence is plain, for it lets down on the south the steep northern
limb of the anticline of Old Red Sandstone.

Fault B has a southerly hade of about 45°, and is seen in the
cliffs on the east side of the bay. This is a reversed fault, as shown
in fig. 10, p. 285.

Fault C, at St. John’s Island, has a downthrow to the north, and
thus, by faults B and C, a mass of Old Red Sandstone is troughed
into the older rocks.

The small rib of red rocks in the bay of Ballydouane West has
rather obscure relations, but it belongs to the northern limb of the
anticline. On the north it is probably cut off by a continuation of
fault A, shifted southward by the transverse fault c up the Bally-
douane stream-vyalley. On the west it is seen to be cut off by a
transverse fault a.

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286 MR. F. R. COWPER REED ON THE RED ROCKS [May 1897,

A transverse fault > is well seen at the western corner of Bally-
douane Bay, bringing the red sandstones against the ‘ ophiolite.’
There may be more than the one transverse fault c at the mouth of
the stream, but the beds are here confused by slips. <A transverse
fault is also supposed to run up the Cooneenacartan valley, shifting
back the outcrop of the Poolatunish block of Old Red Sandstone to
the road and townland of Ballynarrid.

The Bunmahon mass of red beds is cut off on the N.E. by a fault
(1) running towards the E.N.E. from the angle of the bay. On the
west it is cut off by a transverse fault (¢), and on the south side one
of the other set of faults (D) bounds it with a downthrow to the
north, as at St. John’s Island. Bunmahon Head is thus a triangular
mass faulted on all sides (see fig. 8, p. 283). But it plainly belongs
to the northern limb of the anticline. The Knockmahon mass must
also be bounded by faults, but the positions of these are uncertain.

It is thus perfectly possible to account for the occurrence of the
isolated masses of Old Red Sandstone by the faults traceable on the
ground, nearly all of them being clearly exposed on the coast.

Any theory explaining them as strata interbedded with the Lower
Palseozoic rocks is met by extraordinary difficulties ; and I cannot
see how these can be overcome in the face of the evidence of the
sections.

In my opinion all the evidence points to these masses being
faulted inliers of the Old Red Sandstone.

Discussion.

The Presipenr remarked that the paper opened up many points
of considerable importance with regard to the succession of these
red rocks in the South of Ireland, South Wales, and Devon. This
coast of Wexford and Waterford was separated from Pembrokeshire
by only 50 miles of sea, and the experience of the Author on the
Pembrokeshire coast had doubtless helped him to unravel the
complicated structure of the ILrish coast. Faults helped to explain
this complexity—faults which took place at the end of the Carboni-
ferous influencing all the rocks that had been deposited before
that time. Earth-movements had caused so much compression and
faulting as to throw beds out of the true succession into a false one.
Here we had a slice of Old Red Sandstone brought into apparently
conformable succession with much older beds. Such examples, but
much more evident, were seen again and again on the Pembrokeshire
coast. The Author’s lithological evidence was extremely convincing,
and we had to use this in the absence of paleontological evidence.

Prof. Hurt welcomed a paper such as the present on an Irish
subject. He had, unfortunately for the present discussion, never
had an opportunity of visiting the part of the coast of Waterford
described by the Author, inasmuch as before his sojourn in Ireland,
as Director of the Geological Survey, the district referred to had
been surveyed by Du Noyer under the direction of the late
Prof. Jukes. After having listened to the present paper, illustrated

acim

Wiols5 3. NEAR BUNMAHON, CO. WATERFORD. 287

as it was by clear diagrams and good specimens, he felt very much
inclined to concur in the Author’s views. The specimens of con-
glomerate.considered by the Author to have been let down by faults,
and to be discordantly superimposed on the Lower Silurian (or Ordo-
vician) rocks, appeared to him to resemble the beds of the Upper Old
Red Sandstone, rather than those of the Lower Silurian of that part
of Ireland; and considering the whole case, as ably discussed by the
Author, he was disposed to think that the latter’s views had been
made out.

Prof. HueHes had examined some of the rocks described by the
Author in the neighbourhood of Waterford, and so far as his own
observations went they were quite in accord with those of the Author.
He did not see how there could be much doubt as to his inferences,
if the facts which he had recorded and supported by photographs,
sections, and plans were admitted. The crushed-looking weathered
character of the older rocks immediately below the conglomerate
was precisely what we should expect to represent an ancient
Jand-surface. The angular fragments of subaerial talus at the base,
and the tough pebbles in a somewhat oxidized matrix of the over-
lying series, were exactly what must have resulted from the washing-
down of the superficial deposits: of a gradually submerged area.
And all this, together with the evidence of great disturbances
between the deposition of the two series, and the nature of the
movements shown to have occurred since the deposition of the newer
beds, agreed with what was known as to the relations of the
Devonian to the pre-Devonian rocks, but not with the relations
known to exist between the Silurian and Ordovician, or between
any of the several members of the Ordovician.

Mr. W. W. Warts pointed out that the determination of these
rocks as Silurian had been made by Du Noyer, who, after examining
the ground, came to the conclusion that Jukes was right in regarding
them as belonging to this period. Similar, but thinner, red rocks
occurring near Wexford, seen by the speaker and Mr. McHenry,
were intercalated in the Silurian rocks in a district where true Old
Red Sandstone was unknown. If the Author were right as to his
facts, there could be no doubt as to the interpretation of them.

Mr. H. W. Moncxton, Mr. J. E. Magr, Mr. W. Wartraxker, and
Mr. W. V. Batt also spoke.

The AvutHor thanked the Fellows for the manner in which they
had received his paper. Referring to remarks made by the President
and Mr. Watts, he wished to express his sense of the value of the
work of the Geological Survey in that part of Ireland, though he
differed from the Surveyors’ conclusions about the age of these beds.
The faults affecting the red rocks were in his opinion probably con-
temporaneous with the post-Carboniferous folding. With regard to
the view expressed by Mr. Watts that the beds might be of Silurian
age, he thought it highly improbable—firstly, because of their com-
plete identity in character with the typical Old Red Sandstone of
the county, and in their relations to the underlying rocks; and
secondly, because of the complete absence of proof of the deposition

288 THE RED ROCKS YEAR BUNMAHON. [ May 1897.

of any Silurian beds anywhere in the South-east of Ireland. In
order to consider these beds to be of Silurian age, we should have
to suppose, first, the folding, cleaving, and upheaval of the Ordo-
vician rocks, then their great erosion, then their depression and the
deposition of these red beds on their edges in Silurian times, then
the faulting and tilting of these beds coupled with the upheaval of
the area, then a long period of erosion to account for their complete
removal from every other part of the area, then again depression in
' Upper Old Red Sandstone times. And in support of such views,
there is not even the lithological similarity of the red rocks to
Silurian beds, much less the occurrence of a Silurian fossil, or the
evidence of the unconformable overlap upon them of the Upper Old
Red Sandstone, which Prof. Hull has shown everywhere in the
South of Ireland rests with a great unconformity upon all the older
rocks, including the Silurian. There is, moreover, not another
section in the area in which any similar beds occur, except those
belonging to undoubted Old Red Sandstone.

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Vol. 53.] ROCKS ON THE BALUCHISTAN BORDER, 289

22. Notss on some Votcantic and other Rocks, which occur near the
BarucuHistan-AFGHAN FRontIER, between CHAMAN and PERSIA.
By Lieut.-Gen. C. A. McManon, V.P.G.S., and Capt. A. H.
McManon, C.I.E., F.G.S. (Read March 24th, 1897.)

[Puates XVITI-XX.]

Part I.—Tue Batucuistan DESERT, SOUTH OF THE HeLMAND River.
By Capt. A. H. McManon.

WHILE engaged, in the deserts south of the Helmand River, in the
delimitation of the boundary between Afghanistan and Baluchistan,
I made a small collection of such rock-specimens and fossils! as I
thought were characteristic of the geology of the country. I regret
to say that I am not myself a geologist, else my collection would
have been perhaps a more methodical one, and would probably have
been supplemented by notes on the positions and surroundings of
the specimens collected, and on other points of geological interest.
I say perhaps, because even if I had been the most learned of
geologists I doubt whether political and other duties would have
allowed me time to do more than I did. At any rate my collection
would not have been a larger one, for the simple fact that, owing to
long marches and want of water and food, our transport-camels
_ were almost unfit for work, and the mortality among them rendered
it a matter of difficulty for us to carry even the necessaries of life.

Turning now to the physical geography of the country, one finds
in it various natural phenomena on a gigantic scale, the study of
which I venture to think may throw light on similar phenomena
seen elsewhere on a smaller scale. It is a country almost un-
inhabited by man, where man has left nature to do as she pleases
undisturbed. If you look at the map (Pl. XVIII), you see high
mountain-ranges fringing it on the east and south-east. These vary
in height from 6000 to 8000 feet above the sea. West of them lies
a vast wilderness of plains stretching away some 300 or 400 miles
to the mountain-ranges along the Persian border which fringe them
on the west. Rising like rocky islands out of the midst of this vast
sea of plains are mountain-ranges upwards of 7000 feet high. The
north of this tract is bounded by the Helmand River.

We will consider firstly the plains and their drainage-system,
and then the mountains.

The Plains.

We have first of all a wide level plain of alluvial soil which
includes the whole of Shorawak, and then, spreading out from
Nushki on the east to Chagai on the west, it stretches southward to

1 These fossils have been made over to the British Museum (Natural
History).
Q.J.G.8. No. 211. *

cS
rae “1

290 LT.-GEN. C. A. MCMAHON & CAPT. A.H.McMAHON = [ Aug. 1897,

the foot of the Ras Koh and other mountains running south and
west from Nushki. You see the Lora River coming out of the
mountains and crossing the plain in the direction of the Lora Hamun,
where it comes to an end. This river never reaches the Lora
-Hamun, except in flood-time, and then it makes the Hamun a broad
lake of shallow water. This soon evaporates, and for the greater part
of the year the Hamun is nothing but a vast sheet of dry, solid salt.
It is evident that not only the Hamun, but all this plain, must once
have been a great lake, thus accounting for the rich alluvial soil of
which the plain is formed. North of this plain and stretching to the
Helmand River lies the Registan sand-desert—a wide stretch of
billows upon billows of sand with crests some 200 feet high. This

Fig. 1— View showing sand-dunes covering lower slopes of mountains
and gradually overwhelming the higher spurs.

[From a phetograph. |

sand-desert, interspersed with level plains of black gravel, stretches
from the Chagai and other mountains to the Helmand westward as
far as the Persian border. In places this sand-desert is like unto
a fairly calm sea, and the waves of sand are only of moderate height.
In other places, especially along the north of the Koh-i-Sultan,
Damodim, and Amir-Chah ranges, it resembles a wild stormy sea
with great waves 100 or 200 feet high breaking against the sides
of the mountains like the Atlantic surge on a rock-bound coast
(see fig. 1). Here the sand-hills assume the proportions of sand-
mountains. Many of the mountains themselves have become
buried in sand and are no longer visible—others still tower with

Vol. 53.] ON ROCKS FROM THE BALUCHISIAN BORDER. 291

their black crags above the sandy waste, but the sand banked some
1000 or 2000 feet above the level of their base foretells a similar
fate in store for them.

The phenomena of sand-hills—their origin, formation, and pre-
vailing shapes—are in themselves an interesting and difficult study,
and it will be remembered that recently Mr. Vaughan Cornish read
a valuable paper on the subject before the Royal Geographical
Society, which, with the record of the discussion that followed,
deserves the notice of geologists." Suffice it here to note that
some of the speakers on that occasion laid stress on the fact that,
however devouring an element sand may be, water always has the
upper hand, and that a small stream of water will always cut
its way through sand. But in the country here described this
principle does not hold good. If one looks at the map one sees
that the drainage of the mountains from Chagai westward runs in
the direction of the Helmand River, and fartber west still it runs
towards the God-i-Zirreh Lake. Little of that drainage ever
reaches the Helmand River; none of it, so far as I can ascertain,
reaches the God-i-Zirreh. In each case it is stopped by the
sand. After rain, immense volumes of water must run down from
the mountains in the numerous torrent-beds, but it is easy to see
that this water never travels beyond the first few opposing lines of
sand-hills. The God-i-Zirreh was at one time fed by flood-water
from the Helmand, but it does not appear to have received any
replenishment since 1880, that is 17 years ago, and it is now a lake
of salt brine fringed by an ever-encroaching margin of solid salt.
The great Helmand River farther north comes to a standstill in
the lakes and swamps of Seistan.

The Mountains.

The line traced on the map (Pl. X VIIT) from north of Chaman to
Nushki marks the course of a gigantic fault, or earthquake-crack,
which was discovered when we came to carefully examine this
country. It runs in a well-defined line of indentation, as well
marked in places as a deep, broad railway-cutting. It starts at
the edge of the plain north of Chaman and runs along the foot
of the mountains to the point on the Chaman and Quetta railway-
line where the earthquake of December, 1892, so curiously distorted
the track, and shortened the distance between Chaman and Quetta
by no less than 23 feet, as described by Mr. C. L. Griesbach, now
Director of the Geological Survey of India, in the May number of
the Records of that Survey for 1893.’

From that point the fault runs on, gradually ascending diagonally
the slopes of the Khwaja Amran range, until it crosses the crest of
the main range near its highest peak, at an elevation of about 7000
feet. Descending again into the Spintizha Valley it thereafter
ascends diagonally the slopes of a continuation of the Khwaja-

1 Geogr. Journ. vol. ix. (1897) pp. 278-309.

2 Vol. xxvi. pt. ii. pp. 57-61 with 3 plates.
x2

292 ~—=siLT.-GEN. C. A. MCMAHON & CAPr.A.H.MoMAHON [Aug. 1897,

Amran range. Cutting this in a similar manner, it descends to the
Lora River, and, crossing that river, runs along the whole length of
the base of the Sarlat range to Nushki. Beyond this point the
duties connected with boundary-work prevented us from tracing it.

The length of this line, as surveyed by us, is no less than 120
miles. Along the whole course of it we found springs of water,
and, both from the presence of water and from its forming a short
cut across innumerable mountain-spurs, this fault-line is largely used
by the natives as a thoroughfare. The old greybeards of the tribes
living near it told us that on some three occasions during their life-
time, after severe earthquake-shocks, deep fissures had appeared
along this line, and that similar accounts had been handed down
to them by their fathers. After one of these carthquake-shocks
the water-supply of the springs along the crack had, they said,
been largely increased.

The rocks along the east of this fault-line appear to be sedi-
mentary, and the mountains on the east are all of clay-slate. The
rocks on the west are for the most part volcanic and 1 igneous, but
there are a few sedimentaries among them.

In the mountains on the Persian border we again come to
shales and other sedimentary rocks. The Chagai, Koh-i-Sultan,
and other mountains appear to be volcanic; some, like Damodim,
retain their crater-form better than others. Lava, ash, and pumice
abounded in all those localities where the mountains showed above
the sand. The pumice was found lying about in large quantities,
and it was abundantly sprinkled over the sand—whither it may
have been blown by the wind.

Unfortunately, circumstances did not allow of a visit to the crater
of Damodim. Natives told us that in the deep hollow at the top of
that mountain there is some good soil which they are able to
cultivate. All these volcanoes have no doubt long ‘been inactive,
but some 90 miles south-west of them lies the ereat Koh-- Taftan,
also known as the Koh-i-Chehaltan, 12,600 feet high, which is said
to be still an active volcano."

1 [Since this paper was read the authors have been in personal communication
with Capt. P. Molesworth Sykes, British Consul at Karman, now in England
on leave, who climbed the mountain on Christmas Eve, 1893. After gradually
ascending ravines in the foot-hills around the mountain, the exploring party
arrived at the foot of the cone, at an elevation of 10, 000 feet above the sea.
Thence up to 11,000 feet the eround traversed consisted of boulders; but from
11,000 feet up to the top it was covered with fine volcanic ash, into ‘which the
foot sank deeply at every step. Throughout this portion of the ascent the
sinell of sulphur was unpleasantly strong. The summit consists of a plateau
covering an area of about 400 square yards. On its northern and southern
sides there are slight elevations, separated from each other by a narrow but
shallow valley. The northern clevation forms the Sacrifice Hill, where goats
are sacrificed by pilgrims; while the southern portion is called Madar Koh
(Mother Hill). On the latter were, at the time of Capt. Sykes’s visit, two
apertures, some yards apart, each apparently 3 or 4 yards wide, which
appeared to be connected with each other. From both of these dense white
sulphurous smoke and flames were issuing. So strongly sulphurous and suffo-
cating was the smoke that these holes could be approached only from the wind-
ward side, and even that was difficult, owing to the smoke and heat. Sulphur

Vol: 53.] | ON ROCKS FROM THE BALUCHISTAN BORDER. - 293

The Koh-i-Suitan mountains deserve a few remarks, owing to the
curious and grotesque shapes of their high peaks, which remind one
irresistibly of Gothic cathedrals and churches. Here, too, we find a
high natural pillar which, as seen at a distance from the plains below,
looks like an artificial monolith on the crest-line of the range. On
approaching it, we found that it was a huge natural pillar of
stupendous size, made up of volcanic agglomerate. From the width
of the base, which is over 100 yards in diameter, I calculate that
its height must be over 800 feet. Deep fissures down its sides,
caused no doubt by the action of rain, give it a fluted appearance
from a distance. (See fig. 2, p. 294.)

So much for the general character of the country. In considering
the present condition ofits surface and the geological and othernatural
phenomena to be found there, it is advisable to note carefully the
natural agents which are at work in that region with a force and
activity unknown in most other countries. First of all, we have
the agency of water, which is a more particularly destructive agent
here precisely because this part of Baluchistan is one of the driest
countries in the world. Rain comes but seldom, but when it comes
it pours with great violence, and from the absence of vegetation or
surface-soil, it rushes off the mountain-sides in huge torrents. The
high-water marks in the dry torrent-beds and the large rounded
boulders piled one upon another in those beds show with what
volume and force those torrents come down.

Then we have the wind. I have never travelled in a country
where strong winds are so frequent and continued. ‘There is one
wind alone which blows there with hurricane violence continuously

and sal ammoniac were, however, extracted from the edge of one of these
apertures,

Capt. Sykes has paid several visits to the burning petroleum-springs at
Baku, on the western shore of the Caspian Sea, and he is satisfied that the heat,
smoke, and flames on the summit of the Koh-i-Taftan were not due to petroleum.
There was no smell of petroleum, nor was the smoke dark and carbonaceous.

As the summit of the Koh-i-Taftan is still thickly covered with fine ash, this
voleano must have been active during a recent geological period; but as no
very fresh lava-streams appear to have been observed on the way up the
mountain, it is not probable that the volcano has been active during the lifetime
of the present generation. The authors infer from Captain Sykes’s observations
that the voleano is now in the solfataric stage of its existence. The flames seen
were probably due to the emission of hydrogen sulphide (HS), a very common
and inflammable product of solfataric action.

Capt. Sykes brought home with him a specimen of lava found im situ on
the Koh-i-Taftan, and this proves, on examination under the microscope, to
be a vesicular hornblende-andesite. The hornblende belongs to the ortho-
rhombic group, and is identical with the very peculiar red-brown and
brilliantly dichroic variety of anthophyllite described in Part II. of this paper.
It is very abundant in the Koh-i-Taftan slice. Augite is also sparsely present
- init, but there is no olivine. Magnetite and ferrite also occur. The antho-
phyllite has strongly marked resorption-bands, and it is undoubtedly an original
mineral. It is interesting to note that this peculiar mineral is a characteristic
constituent of the lava of the Persian voleano Koh-i-Taftan as well as of some of
be ‘cone older lavas of Baluchistan described in this paper—May 15th,

294. LT.-GEN. C, A. MCMAHON & CAPT. A.H.McMAHON [ Aug. 1897,

for four months, from May to September, every year, and we found
from sad experience that violent storms were not confined to that
season alone. In considering this country we must neither overlook
these strong winds, nor the effect which they have on the sand, nor

Fig. 2.—The Neza-i-Sultan, a natural pillar of voleanre agglomerate.

[From a photograph. |

the destructive effect which, combined with the sand, they have on
everything else. |
Last but not least, great extremes of heat and cold are the rule here,
greater extremes perhaps than are found anywhere else in the world.
The summer heat is terrific, while in the winter there is very severe
cold; and not only is there a wide seasonal range of temperature,

Wakes 341 ON ROCKS FROM THE BALUCHISTAN BORDER. 295

but also a very wide diurnal range. Our solar radiation-thermo-
meter would register 205° F. on cloudless days, while the nights
in the sandy tracts were often bitterly cold. The diurnal variation
must sometimes have been as much as 150° F. It is needless to
point out how powerful an agent these wide variations of daily and
annual temperature must be in the disintegration of the surface of
the country. Nor is there cause for astonishment, if we think of
the peculiar conditions of water, wind, and sand-action and of heat
and cold obtaining in this country, that its surface should present
curious and unusual features.

Part II1.—Perrrotocicat Norss on the Rocks.
By Lieut.-Gen. C. A. McManon.

A numBER of rock-specimens collected by my son, Capt. A. H.
McMahon, C.1.E., Boundary Commissioner, when engaged in the
delineation of the boundary between Baluchistan and Afghanistan
up to the borders of Persia, were made over to me for examination.
Selected samples of these were sliced and studied under the micro-
scope, and the results are embodied in the following pages.

Andesites.
[The numbers are those of the slides in my own collection. ]

No. 1424. Augite-hornblende-andesite. Sp. gr.=2°682

AUC io ae » s e 2720
, 1464. Hornblende-andesite + 2-645
toe. : ey i 2715
» 1426. = s . 2°625
., 1480. Mica-andesite " 2°549
oh) Ay 3, f # 2597
», 1436, Andesite be 2°645

The andesites enumerated above are in some respects very
peculiar rocks, of a type not commonly met with. They vary in
colour from grey to almost white. Many of them are very trachytic-
looking, and some years ago would probably have been classed as
trachytes. As, however, the felspar of which they are built up is
a plagioclase, and not sanidine, they cannot be called by that name.

The specimens grouped together in the above list possess several
features in common.

The first point to be noted is their low specific gravity, which
averages 2-648. The mean specific gravity of quartzless andesites,
according to text-books, ranges from 2°7 to 2°8; so that the average
density of the rocks now described is somewhat low. The percentage
of silica is evidently high, but I have not observed any free quartz
in any of my slides.

The ordinary method of determining the specific gravity of a rock
cannot be applied to these specimens, in consequence of their porosity.
I boiled the samples for some time and allowed them to soak in
water from 24 to 48 hours before weighing them in fresh unboiled

296:. LT.-GEN. 0. A. MCMAHON & CAPT. A. H.McMAHON [ Aug. 1897,

water, but the specific gravity even after these precautions had been
taken was in almost every case too low. The specimens doubtless
contained hidden vesicles filled with air, or gas, which the water
failed to reach. The specific gravities given above were obtained
by the use of a specific-gravity bottle. The rock was reduced to
powder and boiled, and the weighing was done with the aid of a
chemical balance.

The low specific gravities obtained are, I think, innate and
characteristic of these rocks. In one case the low density is due
to the alteration of the felspars, which in this sample were mere
pseudomorphs. Fragments of them were isolated, and their specific
gravity determined with the aid of a heavy liquid and a Westphal’s
balance. It was too low for any felspar. I do not think, however,
that this explanation applies to the rocks generally, for the felspars
in them appear fairly fresh. Oligoclase appears to predominate,
and the density of this species ranges from 2°65 to 2:67. The low
specific gravity of these rocks is due, I think, to the acid character
of the felspars; to the fact that they contain inclusions of glass ;
and to the presence of a glassy base. The mean density of pitch-
stone is 2:34 and of obsidian 2°40. Glass of low specific gravity
seems to be present in sufficient quantity to balance the basic ferro-
magnesian silicates, and leave the rock, as a whole, at the density
of the dominant felspar contained in them, which in these rocks I
would not put higher than 2°65.

The andesites grouped together in the above list are mainly
composed (the accessory minerals will be alluded to later) of
idiomorphic crystals and microliths of felspar embedded in a base
which appears amorphous in ordinary light, but which when revolved
between crossed nicols remains dark in some cases, and in others
breaks up into eryptocrystalline or into microgranular felsitic
material. In one of the first-named cases the glassy base has been
converted into yellow palagonite, but in places the original purple-
brown coloured glass remains. The glassy base during the later
stages of the lava’s history exercised a distinctly solvent action on the
comparatively basic minerals that. had crystallized out from the
still fluid magma, for all the original minerals have been more
or less corroded by it.

The felspar-microliths vary in numbers very much in different.
slices. In some the base is crowded with them, but in one or two
they aresparse. They do not exhibit in their orientation indications
of fluxion except partially, and locally, in their relation to the
larger felspars. In all cases they belong to the oligoclase-felspar
species. Binary twinning, combined with simultaneous extinction,
is common, though, in some cases, more than two macles are to be
seen. The high refraction of those with binary twins, as compared
with the refraction of the Canada balsam of the slide, shows that
they are not orthoclase.

The felspars larger than microliths cannot, be classed as felspars
of first and second generation, for, as a rule, they dwindle gradually
in size from large tabular crystals, or aggregates of crystals, down

Vol. 53.] ON ROCKS FROM THE BALUCHISTAN BORDER. 297

to the smallest microlith. In short, there is a gradation in the size
of the felspars from the largest down to the most minute: this
characteristic is found not only in the felspars, but in all the original
minerals.

Zonal structure is well seen in all the large phenocrysts; and
that this is due to gradual growth is apparent from the fact that
the angles of extinction of the different zones vary, and indicate a
gradual change in the basicity of the mineral.

The larger felspars are sometimes oligoclase and sometimes
andesine, though the former would seem to predominate. Their
species were determined partly by the evidence afforded by the
angles of extinction measured in suitable cases, and partly by the
determination of the specific gravity of isolated fragments.

There can be no question about the species of a considerable
number of the crystals, because the simultaneous extinction of
twins is not uncommon; and that those which exhibit binary
twinning, combined with simultaneous and straight extinction, are
not orthoclase, is shown by the fact that, whenever they occur
in contact with the Canada balsam of the slide, their refraction
is invariably found to be higher than that of the balsam. This
method of distinguishing between orthociase and oligoclase, recom-
mended by M. Michel-Levy,’ seems to be a valuable and reliable
test.

The large felspars are, generally speaking, fairly fresh, but some
are considerably altered. No. 1425 contains some calcite, as a
secondary product of decomposition, in the interior of the felspars ;
and those of No. 1438 contain dusty-looking matter, arranged either
in a central core or as a zonal band inside a rim of water-clear
felspar. This dusty matter may be microscopic granules of limonite,
but it is not magnetite. Fresh felspars, notably those of No. 1424,
contain very characteristic glass- and stone-inclusions with fixed
gas- or air-bubbles, and inclusions of the base. Others possess
liquid inclusions, a few of which contain extremely minute moving
bubbles. :

Magnetite and apatite appear to be original minerals common to
all these rocks. Magnetite is present in all the slices and varies in
size from large grains to minute dots; sometimes it has becn largely
converted into ferric oxide. It occurs as a secondary as well as an
original mineral.

Apatite is present in seven out of the nine slides, and it is some-
times very abundant. The contact-action of the acid base has in
some few cases corroded the crystals, and in some others has pro-
duced a dark ‘resorption’-ring. The crystals that exhibit this
unusual peculiarity are probably mangan-apatites. The hand-speci-
mens treated with nitric acid reacted strongly for phosphoric acid.
Apatite appears to have been one of the first minerals to crystallize
out of the magma.

The three specimens which stand at the top of my list (p. 295)

1 «Etude sur la Détermination des Feldspaths,’ 1894, p. 62.

298 LT.-GEN, C. A. MCMAHON & CAPT. A.H. McMAHON = [ Aug. 1897.

contain, in addition to the minerals above mentioned, a rhombic
amphibole. In transmitted light it is of a rich brown-red colour
and is powerfully dichroic, changing from a golden yellow, when
the direction of elongation of the crystal is at right angles to the
principal section (longer diagonal) of the polarizer, to a rich brown-
red, or red-brown, when the direction of elongation is parallel
to the longer diagonal of the nicol. The mineral possesses straight
extinction, and it appears to be anthophyllite.

Slice No. 1424 contains some very characteristic cross-sections of
prisms of this mineral, which show the intersection of the prism-
faces and the intersection of the prismatic cross-cleavages. They
are quite typical cross-sections of amphibole. The major (+) axis
is, as in rhombic amphibole, at right angles to the direction of
elongation. Moreover, I isolated fragments of this mineral and
determined its specific gravity with the aid of a heavy liquid and
Westphal’s balance, and found it to be exactly that of anthophyllite:
namely, between 3:1 and 3:2.

The anthophyllite appears to be an original mineral in these recks.
Crystals of felspars are caught up in it, and in Pl. XIX, fig. 3, a case
is depicted where a large augite has caught up and enclosed a frag-
mentary-looking crystal of anthophyllite. That the latter is an
original inclusion in the augite appears plain, from the fact that
contact-action has produced a dark halo round the anthophyllite.

The case represented in Pl. XIX, fig. 4, is an interesting one, and
bears directly on the question at issue. The anthophyllite, when it
began to crystallize, formed on the lower half of a felspar-microlith.
The growth of the felspar in that direction was arrested, but it con-
tinued to grow and widen along its upper half where the anthophyllite
did not interfere with it. Similar cases of interference between
growing crystals of augite and felspar are often seen in basalts ;
but the case has a special importance in the study of these rocks, as
it shows conclusively that the crystallization of the smaller felspars
and the anthophyllite was contemporaneous.

Rosenbusch, in his work on rocks,’ notes that a brown hornblende
with an extinction-angle ranging from small to nothing is known
to occur in some andesites. In the slices above described the angle
of extinction is uniformly nd.

In Nos. 1424, 1438, and 1464 all the amphibole consists of antho-
phyllite ; but the first two contain in addition a considerable amount
of augite. In transmitted light it is of a somewhat pale brown-
green colour, sometimes putting on a purplish tint: it shows no
dichroism. A single cleavage predominates, but more or less distinct
traces of a cross-cleavage may sometimes be seen. The augites
occasionally exhibit crystallographic outlines, but are more frequently
allotriomorphie.

The augite-hornblende-andesites, Nos. 1424 & 1438, are remarkable
for containing crystals of olivine. Rosenbusch, in his work already
referred to, mentions that olivine sometimes occurs in andesites,
but one would certainly not expect to meet with this mineral in a

1 “Mikroskopische Physiographie der Massigen Gesteine, 2nd ed. (1887)
p. 659.

Vol. 53.] | ON ROCKS FROM THE BALUCHISTAN BORDER. 299

rock of the intermediate class which inclines towards the acid type.
In transmitted light it is of so pale a greenish-white as to be almost
colourless. The refraction is high, and the surface is rough and
shagreened. Traces of a fine interrupted cleavage are to be seen,
and the mineral has straight extinction with reference to this
cleavage. It has also the deeper and more irregular cracks so
commonly seen in olivine. The form is sometimes roughly idio-
morphic, and photographs of two (one from No. 1424 and the other
from No, 1438) are reproduced in Pl. XIX, figs. 5 & 6, which show
the pointed terminations characteristic of olivine.

Several of these olivines, as in Pl. XIX, fig. 5, have a deposit of
the brown-red anthophyllite round a portion of the outer edge of the
olivine. Rosenbusch? notes the alteration of olivine, beginning with
the periphery of the latter mineral, into needles of tremolite, actino-
lite, and anthophyllite, owing to the mutual influence of the olivine
and the adjacent rock-constituents, and states that this is known to
occur only in the Archean rocks. At first sight, the anthophyllite-
fringe above described would seem to be a case of alteration similar to
that noted by Rosenbusch; but in view of the fact already shown,
that the anthophyllite in these rocks is an original congenital mineral,
I think it is more probable that the anthophyllite round the margin of
the olivines is of the nature of an intergrowth. It does not occur in
needles, and so far from these andesites being of Archean age, there
is reason to believe that they are, geologically speaking, compara-
tively modern. Numerous crystals of anthophyllite occur in these
slides, in forms that could not possibly be referred to olivine.

In the next two slides, Nos. 1425 & 1426, ordinary monoclinic
hornblende takes the place of anthophyllite. It is of a brownish-
green colour—the green element being very distinct; it is strongly
dichroic, and the angle of extinction issmall. It was evidently one of
the first minerals to crystallize out, and it has suffered much from the
corrosive action of the more acid magma. Many of the crystals are
rounded and corroded, and all have a broad black ‘ resorption-’
margin of magnetite.

The condition of the hornblende in these sections confirms the
conclusion arrived at regarding the anthophyllite: namely, that the
amphibole in these rocks is an original mineral, and crystallized out
before the magma ceased to be fluid.

In Nos. 1430 & 1443 amphibole gives place to mica. In trans-
mitted light the mica varies from a yellow-brown to a greenish
brown. It has suffered much, and has been corroded by the solvent
action of the liquid magma. It is present in good-sized leaves and
packets, and also (No. 1443) in the form of fibrous microliths.

No. 1436 closely resembles the rocks above described in its general
characteristics, but it does not contain any amphibole. It is much
altered and contains some secondary minerals, such as zoisite and
ferric oxide, the latter partly infilling some of the felspars. There
is also apparently the remnant of an augite.

1 “Microscopical Physiography of Rock-making Minerals,’ transl. &
abridged by J. P. Iddings, 1888, p, 217.

3800 = La.-GEN. c. A. MCMAHON & CAPT. A.H. MCMAHON =. [Aug. 1897,

Felspathic Lavas.
No. 1434. Sp. gr.=2°751. From the Shibian Kotal
2 2°847

” 1429, ” ° 9 Amir Chah.

spe TARGEGS 14; 2°851. ‘3 Amir Chah.

These rocks seem to lie intermediate between the andesites proper
and the basaltic lavas.

No. 1434 is a light greyish, elle eachte coloated: slaty-looking
felsite. It is composed of crystals of oligoclase set in a micro-
felsitic base. The felspars look like fragments, and suggest the
possibility of the rock being an altered ash; but I think this is prob-
ably owing to the partial remelting and deep corrosion of the felspars
by the base when liquid. The rock is considerably altered, being
dotted over with epidote, which has also formed in some of the felspars.

No. 1429 is a dark, blackish-grey, compact lava. The slice is
composed of a matted mass of microliths and idiomorphic pheno-
crysts of felspar, set in what seems to have been originally a
glassy base. The base, together with the major part of the large
felspars, has been altered into a structureless chlorite. Opalescent
quartz and epidote have been introduced along and adjoining cracks,
and the slice is dotted over with colourless epidote, and minute spots
of a mineral, opaque in transmitted but white in reflected light,
which is probably a leucoxenic variety of sphene. The microliths
and small felspars have straight extinction, and their refraction is.
precisely that of the Canada balsam in which the slice is set. They
are probably oligoclase.

No. 1416 is a light grey lava, mottled with crystals of felspar
visible to the unaided eye. Under the microscope it is seen to
be made up of felspar-phenocrysts and a matted mass of micro-
liths, embedded in a microgranular devitrified base. Some of the.
phenocrysts are quite rounded, others present more or less perfect
crystalline forms. (See Pl. XX, fig. 2.)

The porphyritic felspars are so highly altered that their species
cannot be satisfactorily made out. For the most part they appear
to possess straight extinction, but it is impossible to say whether this
is a property of the original felspar or of the pseudomorphous and
extremely feeble birefringent mineral that has more or less replaced
it. Two fragments of these felspars yielded respectively specific
gravities of 2°840 and 2:735. The refractive index of the latter
proved to be 1557. Taken together, these data point to the felspar
being labradorite ; but the alteration that the mineral has undergone
prevents me from pronouncing a definite opinion as to its identity.

The microliths have straight extinction, but the medium-sized —
felspar-prisms extinguish obliquely. . There is no uniformity in.
their size or shape. Some are rectangular, some lath-shaped. Some
are short and stumpy; others are long and slender. . Many of.
them are ragged and ‘unfinished’ at their ends, and some have ©
rod-like microprisms projecting from their terminal faces. Some
are quite skeletal, and contain inclusions of the base. A few .
exhibit binary twinning obscurely—none multiple twinning. The
microliths are presumably oligoclase.

Vol. 53.] ON ROCKS FROM THE BALUCHISIAN BORDER. 301

Basaltic Rocks.

No. 1463. Sp. gr.=2°828. From Bharab Chah.
SC: 2-888. » Amir Chah.

No. 1463 occurs as a dyke 44 feet wide, running up vertically
through the granite of which a hill at Bharab Chah is composed. It
is a compact, dark greenish-grey basalt. Under the microscope it
is seen to be composed of crystals of augite, felspar, and magnetite.
The augites are sometimes club-shaped, but are mostly in very
irregular forms. They are much cracked and penetrated by infil-
tration-canals. ‘he pyroxene exhibits no dichroism, and its double
refraction is not strong, showing generally the yellow, and occa-
sionally the red, of Newton’s first order. It extinguishes at from
25° to 30° from the cleavage-lines, when only one set is seen.
Cross-cleayage is not well developed, but when visible a single bar
is seen in converging polarized light.

The felspar-prisms are mostly lath-shaped, and generally show
straight extinction. Multiple twinning is not to be seen, but a
few show traces of binary macles. The refraction of the felspar is
higher than that of the Canada balsam, which shows that they are
not orthoclase. The binary twinning and straight extinction seem
to indicate that some of the felspars, at any rate, are oligoclase.
This is not improbable, as this rock is probably allied to the
andesites previously described, and oligoclase is very characteristic
of them.

This specimen is highly altered. None of the minerals are at all
fresh, and the felspars especially have become very opaque from
the formation of secondary granular mineral matter in them. A
chloritic-serpentinous mineral, varying in colour from pale green to
reddish brown in some cases and yellow-green in others, is very
abundant: it is distinctly dichroic. Whether this represents in
places a glassy base, or whether it is wholly altered felsitic matter,
is difficult to say. The rock would, by many, be called a melaphyre
or diabase, but I prefer to name it altered basalt.

No. 1422 is a compact rock of purple-black colour, which is said
to be very abundant at Amir Chah. It consists of iron micro-
granules, set in a base composed of aluminous serpentine.

The iron is in part magnetite and in part limonite. It varies
from opaque to translucent, and in colour from a deep brown to a
black-brown. It is disseminated through the slice in microgranules
and in irregularly-shaped patches, which rarely coalesce into uniform
and unbroken masses. It nowhere presents crystalline outlines.

The serpentinous groundmass remains dark when revolved be-
tween crossed nicols, but countless fibres and dots of doubly-
refracting material, probably chrysotile or kaolin, shine like stars in
the Milky Way. In this groundmass, pseudomorphs of felspars,
pyroxene, and olivine can be made out, the original shapes of the
minerals being outlined by deposits of iron oxide. No trace of
twinning can be discerned in the felspars, as none of the original

302 LT.-GEN. C. A. MCMAHON & CAPT. A. H.McmMAHON. [Aug. 1897,

substance of any of the minerals remains, all having been converted
into iron oxide and serpentine,

Pieces of the rock ground down to fine powder were digested in
hot hydrochloric acid, and yielded a large amount of iron, a con-
siderable amount of magnesia, an appreciable amount of alumina,
and a little lime. The residue consisted of quartz with mineral
matter caught up in it. This was treated with hydrofluoric and
sulphuric acid, and it yielded a little iron, a little lime, and a good
deal of magnesia. The residue untouched by the hydrofluoric and
sulphuric acids consisted of iron that dissolved in hot nitrohydro-
chloric acid.

The rock does not attract the magnet, showing how much lmo-
nite preponderates over magnetite.

Pumice.

No. 1423. From Amir Chah.
99 1433. 9 39 39

These are samples of the pumice sprinkled in abundance all over
the country around Amir Chah.

No. 1423 is a highly vesicular lava. The remains of felspars are
abundant in the slice, but they are all so highly altered that they
remain dark between crossed nicols. The slice contains flecks
of calcite here and there, and some leucoxene-pseudomorphs after
ilmenite.

No. 1433 is also a highly vesicular lava, and is composed of a
colourless glass, drawn into fibres and full of air or gas-bubbles
round the vesicles. The slice contains some fibres of mica, one
or two fragments of hornblende, one or two felspars with straight
extinction, and some small flakes of quartz, evidently extraneous
fragments. It is dotted over with granules of calcite, and the hand-
specimen effervesces strongly with an acid.

Volcanic Ash-beds.
No. 1418. From the west side of the great fault. Sarlat Range.

», 1427. Bi Gazi-Chah hills.

” 1428. ” ” ”

», 1489. 43 Shibian Kotal.

” 1440. ” ” 7

” esis ” oP) ”

,, 1445. a Gargarok.

,, 1450. west side of the great fault.

», 1465. . natural monolith, Neza-i-Sultan.

The above specimens of volcanic ash do not require separate
description. They are all fine-grained, almost compact-looking
rocks, varying in colour from purple-grey to greenish grey. They
are composed of fragments of various kinds of lavas of the inter-
mediate class, fragments of limestones and crystals of felspar.
These ashes have been much altered by aqueous agencies, and

Vol. 53.] ON ROCKS FROM THE BALUCHISTAN BORDER. 303

some of them intensely so. In No. 1418 the interstitial portions
have to some extent been converted into a serpentinous product,
and in others epidote and calcite have been found as secondary
products.

No. 1427 was difficult to interpret, as the fragments were all of
very much ‘the same kind of lava; but on having a thicker slice
made, and after digestion in hot hydrochloric acid, the distinction
between the different lavas could be well seen, and the fragmentary
character of the rock came out clearly.

Among the lapilli are fragments of a dark basic lava, but I have
not observed any of olivine-basalt.

No. 1465, from the natural monolith of Neza-i-Sultan, is a fine
ash made up of fragments of trachyte-looking andesites, so like each
other that it is difficult to distinguish the ash from a lava.

Holocrystalline Rocks.
No. 1462. Biotite-hornblende-granite.

The hill at Bharab Chah previously mentioned (p. 301) is com-
posed of this granite. The slice taken from my hand-specimen
contains orthoclase, oligoclase, quartz, apatite, biotite, and a little
hornblende, zircon, and sphene.

The hornblende is brown-green in transmitted light. It is not
by any means as plentiful as the biotite, which is a good deal
decomposed and here and there altered into chlorite. Apatite is
rather abundant. The quartz deeply corrodes the felspars, horn-
blendes, and micas. (See Pl. XX, figs. 5 & 6.)

The solvent action of the acid matrix on the more basic materials
that had previously crystallized out seems to be a rather frequent
feature in granites, and it appears to mark that stage in the history
of the rock when the granite, full of crystals formed under plutonic
conditions, was moved upwards into place, and partial re-solution
commenced from relief of pressure and consequent lowering of the
point of fusion and from othercauses. The corrosion of phenocrysts
by the matrix in the case of quartz-porphyries has been often
described ; but in the case of granites this partial re-solution of the
first-formed minerals does not appear to have been noticed by
previous observers.

Liquid inclusions are common in the quartz, but no moving bubbles
of any size are to be seen.

No. 1421. Quartz-syenite. Sp. gr.=2°750.

From the west side of the great fault at Chili Katch in the Sarlat
Range.

The hand-specimen exhibits a somewhat obscure parallelism of
structure which is not noticeable under the microscope. The slice
contains oligoclase, orthoclase, quartz, hornblende, biotite, apatite,
sphene, and magnetite, with some epidote, calcite, and chlorite, as
secondary products of decomposition.

304 LT.-GEN. C. A. MCMAHON & CAPT. A. H. MCMAHON = [ Aug. 1897,

Oligoclase is the most abundant mineral, The quartz and ortho-
clase are present in about equal proportions, but each taken
separately is very subordinate to the plagioclase. The latter, by its
extinctions and specific gravity, 1s seen to be oligoclase.

Both felspars are fairly fresh, and as a rule are allotriomorphic ;
but there are two crystals enclosed in biotite which possess crys-
tallographic outlines.

In transmitted light the hornblende is of a green to brownish-
green, and the biotite of a greenish to reddish-brown colour. The
biotite is altered in places to chlorite. Epidote occurs; intergrown
with chlorite in elongated granules running in the direction of the
biotite and chlorite cleavage-planes. The hornblende and biotite
are deeply corroded by both the quartz and the plagioclase. (See
Pl. XX, figs. 3 & 4.)

Apatite is abundant, and occurs in the biotite, felspar, and quartz,
while the magnetite, as one so often sees in igneous rocks, is often
formed upon the apatite.

Sphene is somewhat abundant, and is in good-sized grains ; it
rarely shows any approximation to crystalline shape. It is dis-
tinctly dichroic, and exhibits a tendency to a fibrous habit. It
has the prism-cleavage strongly developed in one direction, with
traces of another cleavage crossing it at an angle of 111° to 117°.

The quartz contains liquid cavities with small moving bubbles
and fine needle-shaped crystals which are probably rutile.

Sedimentary Rocks.

No. 1410. From Amir Chah.
jo LLB 2, %»
1412. if 3
» 1414. % ss
», 1415. 3 5
1449. x the east side of the great fault.
» 1453. 4 the west side of the great fault.

The first five samples are apparently very fine-grained sedi-
mentary rocks of the character of indurated. muds. They are
porcellanous-looking, and not unlike felsites. They do not exhibit
cleavage orlamination. ‘They are brittle, and fuse at the edges, but
the fused edge is not magnetic.

The groundmass of some felsites and porphyries resembles the
structure of these rocks as seen under the microscope; but these
samples do not contain any embedded crystals, or other indication of
igneous structure.

No. 1449 is a glossy, silty shale, with much of the aspect of a
slate. Under the microscope it is seen to be extremely fine-grained.

No. 1453 is a fine-grained, indurated silt, formed of flaky silica
deeply impregnated and stained a reddish-brown colour with limo-
nite. The groundmass contains a number of round, oval, and
angular grains and elongated fibres of calcite scattered through it.
In some cases opal has replaced the calcite. The quartz is in
irregularly-shaped flakes.

Vol. 53.] ON ROCKS FROM THE BALUCHISTAN BORDER. 305

The rock contains countless vein-like cracks, which are wide at
one end and branch out freely until they dwindle down into
channels of hair-like fineness and disappear. These cracks ana-
stomose, bifurcate, cross each other at various angles, and sometimes
disappear to reappear farther on. They are all filled with calcite.
In some of the hand-specimens not sliced, and not enumerated above,
the calcite in quantity at least equals the silt with which it
appears to be inextricably mixed up.

One of the sub-rounded grains of opal is traversed by two
calcite-filled cracks, whence it would appear that the rounded
bodies composed of calcite and opal were original components of the
silt, and were not introduced by infiltration when the calcite-veins
were formed.

The silty part of the rock, from its appearance under the micro-
scope, I should say was probably formed in the sea at or near the
foot of acoralreef. Whether the cracking was caused by shrinkage
on consolidation, or whether the rock is a fault-breccia, cannot be
determined from the examination of hand-specimens alone.

In conclusion, I proceed to enumerate briefly various rocks and
ores given to me for determination. The most convenient plan will,
J think, be to group them under the localities in which they were
found. .

Saindak Mountains.

(1) Galena, or sulphide of lead. This appears to be fairly pure.

(2) Silicate of copper (chrysocolla).

(3) Calcareous epidote-rock. It is composed principally of epi-
dote, calcite, and iron. It is probably the product of the
alteration of a volcanic or igneous rock.

(4) Reddle, or earthy hydrated ferric oxide, containing numerous
crystals of selenite, lumps of gypsum, and small erystals of
anthophyllite.

(5) Sand. This fine-grained, somewhat earthy-looking sand was
found, on examination under the microscope, supplemented
by some chemical tests, to be composed of minute frag-
ments of the following minerals and rocks :—quartz, calcite,
dolomite, carbonate of iron, garnet, tourmaline, muscovite, a
reddish-brown mica, orthoclase- and plagioclase-felspars, and
fragments of siliceous rocks. The calcite and dolomite were
probably derived from limestone and magnesian-limestone
rocks, near at hand.

Koh-i-Sultan.

(1) Yellow ochre, used by the natives as a dye. This rock is
composed of limonite, with some sulphide of iron and a good
deal of silica as impurities.

(2) Red ochre. The red ochre contains many crystals of gypsum
and numerous minute crystals of anthophyllite.

(3) Sulphur, with some yellow limonite as an impurity.

@.d.G:. S.No, 211. Y

3006 =LT.-GEN. ©. A. MCMAHON & CAPT. A. H. MCMAHON [Aug. 1897,

Koh-i-Malik Siah.

(1) Red jasper interspersed with white quartz and chalcedony.

(2) Epidote-rock, composed of epidote- and quartz-crystals, the
former predominating. The quartz contains inclusions of
ferric oxide.

(3) Chrysocolla, in a matrix composed principally of silica, with
fragments of mica and other minerals.

(4) Galena or sulphide of lead.

(5) Small fragments of basic igneous rocks.

(6) Fragments of fine-grained biotite-granite.

Malik Dokhand.

Crystalline granular gypsum (alabaster).

Malik Ainak.

Selenite.

EXPLANATION OF PLATES.

Puats XVIII.
: ; salen Pont me
Sketch-map of the Baluchistan-Afghan frontier, on the scale of 3,000,000
47°3 miles=1 inch.

or

Pratr XIX.
a=biotite. cde=quartz. f=anthophyllite. h=hornblende. o=olivine.

Fig. 1. General view of augite-hornblende-andesite. No. 1424.

2. Section of the anthophyllite seen in fig. 1 (enlarged).

3. Brown-red anthophyllite (with contact-halo) enclosed in an aggregate
of pyroxene-grains and prisms, the granular complex having the form
of a crystal. See p. 298.

4. Contemporaneous crystallization of plagioclase and brown-red antho-
phyllite. See p. 298.

5. Olivine, with deposit of brown-red anthophyllite round its margin;
enlarged from No. 1424 (fig. 1). See p. 299.

6. General view of augite-hornblende-andesite, No. 1438, showing olivine.

See p. 299.
Puate XX.
Fig. 1. Augite-hornblende-andesite. Another portion of No. 1438 (Pl. XIX,
fig. 6). |

. Felspathic lava. No. 1416. See p. 300.

. Quartz-syenite. Corrosion of hornblende by quartz. Between d and h
and between ¢ and h the quartz has eaten deeply into the hornblende
all round. At d it has forced its way into cleavage-cracks; while at }
the process has proceeded further, and a piece has been split off from
the main crystal of hornblende. See p. 304.

4. Quartz-syenite. Corrosion of biotite by quartz. The quartz has cut
deeply into the biotite all round its margin. Between 6 and d
the quartz by its solvent action has nearly severed the biotite into
two portions. This can be seen with the aid of a pocket-lens.

5, Hornblende-biotite-granite. Corrosion of hornblende and biotite by
quartz. The biotite has at d been cut in half and corroded all
round by the quartz. Seven distinct bays of corrosion can be counted.

6. Hornblende-biotite-granite. Corrosion of hornblende by quartz. Bays

of corrosion are to be seen all round the hornblende. See p. 303.

os bo

Quart. Journ. Geol. Soc. Vol. LIII, Pl. XVIII.

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Quart. Journ. Geol. Soc. Vol. LILI, Pl. XVIII.

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SKETCH-MAP OF THE BALUCHISTAN-AFGHAN FRONTIER.

[Scale: —>2a55 or 47°3 miles=1 inch.]
” ,

Quart. Journ.Geol. Soc Vol. LIT. P1_XIX.

FH Michael del.et kth.
ROCKS FROM THE BALUCHISTAN-
AFGHAN FRONTIER.

Mantern Bros .imp.

Quart. Journ.Geol.Soc.Vol. LIL PLXX.

Mintern Bros.imp.

FH Michael delet hth.

ROCKS FROM THE BALUCHISTAN-

AFGHAN FRONTIER.

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Vol. 53. | ON ROCKS FROM THE BALUCHISTAN BORDER. 307

Discussion.

The PresipeNtT commented on the advantage of heredity in taste,
and on the excellent observations made by Capt. McMahon, as well
as the valuable information which he had brought back. Con-
cerning the corrosion of basic minerals by silica, he observed that
silica might be truly a corrosive mineral, but hitherto the idea had
been that the basic mineral had decomposed in situ, and that the
silica had filled up the hollows and cracks resulting from this
decomposition. It was perhaps a general mistake to suppose that
faults always run along valleys. Faults may often be indicated by
valleys, but in many parts of the country they run across the ridges
as well.

Mr. Grizssacu considered the paper just read a valuable contribu-
tion to our knowledge of Baluchistan. But, having spent some years
in that part of Asia himself, he wished to point out that there is
abundant evidence to show that the Pliocene deposits which are
seen in Shorawak and the neighbouring Registan have not been laid
down in a lake-basin, but are chiefly of a fluviatile nature. The range
of hills, of which the northern portion is known as the Koh-1-Khwaja
Amran, is composed mostly of rocks belonging to the later Cretaceous
and Nummulitic formations, with great masses of intrusive igneous
rocks. Of these latter the peak of Khwaja Amran is the nucleus, and
represents a remarkable series of acid rocks, followed by ‘ Nachschiibe’
of basic rocks. The long fault-line or ‘earthquake-crack’ does not,
however, mark the boundary-line between sedimentary and igneous
rocks in that part of the world. Quite close to the line of fault, west
of Chaman, Hippuritic Limestone may be seen 2n situ ; and rocks of
Cretaceous and Tertiary age form great mountain-chains north-east of
Chaman and west of the ‘earthquake-crack.’ It is questioned whether
there is any foundation of truth for the rumoured existence of
actual recent craters in the desert west of the Koh-i-Sultan. Nearly
all the ridges and peaks of volcanic rocks in this Baluchi desert are
due to their having been laid bare by the decomposition and removal
of the softer sedimentary strata into which they have been in-
truded.

Dr. W. T. Branrorp congratulated Capt. McMahon on the series of
interesting observations brought before the Society. He noticed the
great prevalence of Tertiary and Cretaceous rocks throughout the
wide area extending from the Indus to Mesopotamia. The volcanic
rocks of Eastern Baluchistan, like the Deccan traps of India, appear
to be of Cretaceous and Lower Eocene age ; but the igneous forma-
tions near the Baluchistan and Persian frontier must be, in part at
all events, of far more recent origin, some of the cones of loose
materials seen by the speaker between Bampur and Bam having
undergone no change through denudation. Possibly the great
voleanic eruptions of this area had some connexion with the lateral
compression of the rocks in Southern Baluchistan, Tertiary rocks
being found vertical or nearly so, from near the shores of the Indian
Ocean to Jalk, about 150 miles across the strike. The remarkable

x2

308 VOLCANIC & OTHER ROCKS FROM THE [Aug. 1897,

pinnacles of agglomerate noticed by Capt. McMahon were difficult
to explain.

The Rev. Epwin Hizz said that the paper teemed with points of
interest. The pinnacle shown resembled a magnified earth-pillar.
Was the water which disappeared in the sand ultimately evaporated ?
That the great fault in its course disregarded mountains seemed an
indication of its depth.

Prof. Mitne made special reference to the fault which Capt.
McMahon had described, and compared it with a fault which
in 1891 had been formed in Japan. The time at which the
Indian fault had been created was not known; but, from earth-
quakes which from time to time originated along its length, it was
clear that the forces which had crushed together and uptilted the
strata in this region were not yet extinct. One of the most
striking phenomena which accompanied the formation of the
Japan fault was the permanent compression of the land in its
vicinity. River-beds were reduced in width to an extent of
1 or 2 per cent., while certain plots of ground had their sides
shortened in the ratio of from 10 to 7.

Mr. Cavett said that the remarkable peaks described by the
Author, which were said to be of agglomerate, might be explained
on the supposition that these were the necks of old volcanoes, the
upper parts of which, together with the surrounding strata, had
been denuded away.

Prof. Jupp called attention to the great steep-sided masses of
volcanic agglomerate which rise up in the midst of the town of
Le Puy in Central France, and are crowned by the Cathedral and
the church of St. Michel. These seem comparable, though of
smaller dimensions, with the great columnar masses described by
Capt. McMahon. There is no doubt that the masses of Le Puy are
relics left by denudation of a mass of volcanic agglomerate that
once filled the whole valley. The reason why these masses have
escaped removal by denudation is probably not because they are
‘ volcanic rocks,’ but because these materials have been consolidated
by the action of siliceous, calcareous, or chalybeate springs.

Dr. H. Woopwarp and Mr. W. W. Warts also spoke.

Capt. McManon observed, with reference to what Mr. Hill had
said about the way in which the drainage from the mountains
had disappeared when intercepted by the sand, that, although it
disappears below the surface, water can be found in places ata
very slight depth below the sand, sometimes only a foot or two
below the surface. The great difficulty is to find those spots,
as the configuration of the country does not guide one so much
in finding it as in the case of sub-surface water under other con-
ditions.

Then with reference to the supposition that the pillar of Neza-i-
Sultan may be the neck of some old volcano, he pointed out
that there are numerous peaks of grotesque shape in the near
neighbourhood of the Neza-i-Sultan, all apparently made of the
same rock and all probably reduced to their present curious shapes

Vol.5 3°) BALUCHISTAN-AFGHAN FRONTIER. 309

by the same natural process. If the Neza-i-Sultan is to be con-
sidered the neck of a volcano, these other peaks should, by the same
process of reasoning, be also considered to be necks of old volcanoes.
But their number and proximity to each other would tend to throw
doubt on the correctness of that supposition.

Gen. McManoy, in reply to Mr. Griesbach, remarked that the
Authors had not attempted to determine the precise age of the
lavas, as the fossils brought home by one of them were still under
examination in the Natural History Museum; but the volcanic
eruptions had evidently extended over a considerable period. The
Neza-i-Sultan (Spear of Soliman) contained fragments of the
peculiar augite-hornblende-andesite identical with the lava found
in situ elsewhere, showing that the latter must have consolidated
before the beds of agglomerate were formed. The subsequent
erosion of hundreds of feet of agglomerate, moreover, indicated the
lapse of a long period since the formation of these beds.

With reference to Mr. Hill’s remarks, he suggested that a con-
siderable amount of water might be retained near the surface
of sand-hills by capillary attraction, and instanced the growth
of good autumn crops on the borders of Bikanir, on hills that
seemed to the eye pure drifted sand.

310 MR. D. DRAPER ON THE OCCURRENCE OF [Aug. 1897,

23. Nores on the Occurrence of Siei~taria, GtossopTERIs, and
other Puant-REMAINS in the Triassic Rocks of Sourm AFRIca.
By Davip Drarsr, Esq., F.G.S. (Read March 24th, 1897.)

A coLtecrion of plants was forwarded by the writer to Mr. A. C.
Seward, M.A., F.G.S., for identification. These were found at the
following localities, marked on the accompanying map.

{ Boschmans Fontein.
| Maggies Mine ....

| Middelburg District, Transvaal.

2. Casey’s Township.. Two miles south of Johannesburg.
3. Vereeniging... i... Thirty miles south of Johannesburg.
4. Zwart Koppies.... Four miles west of the Heilbron Road

Station on the Cape Government
Railway-line to Johannesburg.

Fig. 1.—Sketch-map showing the localities where the fossils were discovered.

Yj

8G fY/Quarry =

Qe =e
=) v= Co

nd

i

|
i

Aki

ees a pe
ms ae... ————————— nr CSS :

(COGHE WUD. TEATS oo |
Carboniferous and Devonian Rocks---- Wd
Granite and Schists.— 2 _-~—~.—---— LEX}
BIC CLLOTUMWUILG Sia na a ee

All these localities are situated within the area which is known
to be coal-bearing, excepting No. 2, Casey’s Township, which is a
small outlier, detached from the main body by denudation.

Vol. 53.] SIGILLARIA, GLOSSOPTERIS, EIC., IN SOUTH AFRICA. oLk

The coal-bearing rocks of the Transvaal belong to the horizon
which is known in South African geology by the name of ‘ Molteno
Beds,’ the lower member of the Stormberg Beds (Dunn), generally
assumed to be of Triassic age. .

The accompanying sections (figs. 2 & 3, pp. 312, 313) demonstrate
the position of the Molteno Beds with regard to the underlying rocks.
It will be seen that they rest unconformably upon tilted strata,
beneath which the beds are generally believed to be of Carboni-
ferous age, though but few fossils have been found in proof of this
assumption.

In general, and especially at Vereeniging, a boulder-bed, con-
taining large rounded masses of quartzite, conglomerate, dolomite,
and other rocks, all of which have evidently been derived from the
older series exposed to the northward, lies upon the eroded surface
of the underlying rocks; this boulder-bed apparently represents an
ancient beach-line, no traces of which have as yet been found at a
higher level than the present outcrop of coal-bearing rocks.

Geology of the different Localities where the Fossils
were discovered.

No. 1. Boscumans Fontrern anp Macetes Mine.

The former of these is situated near the extreme northern limit
of the Molteno Beds, lying within the boundaries of the Transvaal.
Immediately to the northward, rocks identical with those occurring
in the Megaliesberg and Gats Rand (probably Carboniferous)
occupy a large extent of country. These are generally much
contorted and dip towards the north. The coal-bearing strata
(Molteno Beds) lie unconformably upon these older rocks, and
terminate on the northern portion of the farm of Boschmans Fontein.
A coal-seam has been opened about 1 mile east of the home-
stead on this farm. It is about 12 feet in thickness, though in the
working, which has been continued about 150 feet into the coal, the
upper portion (about 6 feet) of this large coal-bed has been removed
by denudation, and its position has been filled up by grey shale and
coarse gritty sandstone: it is in the former that the fossil plants
were found by the writer.

Maggies Mine, situated on the farm of Vaal Bank, lies about
9 miles south-east from Boschmans Fontein, and is on the main
bed of coal. Near the present colliery-shaft a bed of fossils was
discovered, and the specimens were forwarded to me by Mr. W. H.
Roach, then manager of the property.

The coal-mine on this farm is situated at a greater distance from
the northern limit of the Molteno Beds than the open working at
Boschmans Fontein.” (See map, fig. 1.)

No. 2. Casny’s Townsuip
(2 miles south of Johannesburg),

At this spot the fossils were found in sinking a well on the
property belonging to Mr. Francis (hence called ‘ Francis’ in

312

Fig. 2.—Section at Vereeniging.

(é)

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Flagstones

Vereeniging

Coal Vaal River

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D. DRAPER ON THE OCCURRENCE OF

[Aug. 1897,

M. Zeiller’s recent description of
some South African fossils sent
him by M. de Launay).

Fine sedimentary deposits,
grey, white, or red in colour,
were traversed in sinking the
shafts, and in these the numerous
plant-remains were found. The
material in which they were
preserved was for the most part
so soft and crumbly that many
very fine specimens were lost
when the rock was exposed to
the atmosphere.

At the depth attained in the
shaft (about 80 feet) coarse gritty
sandstone was intersected for
the last 6 or 8 feet, and this was
found to rest upon the tilted
edges of the Upper Quartzite-
and-Shale Group, containing
conglomerates, which are iden-
tified as belonging to the
Table Mountain Sandstone Series
(Upper Devonian).

As these rocks erop out all
round the small patch of hori-
zontal shale and sandstone in
which the fossils were found,
this latter is undoubtedly an
outlier detached from the main
body of the Molteno Beds—
which lies about 12 miles south-
east — by ordinary -subaerial
denudation.

No. 3. VEREENIGING.

This place, a small township,
lies about 30 miles due south
of Johannesburg on the northern
bank of the Vaal River. The main
trunk-line of railway connecting
the Cape Colonial seaports with
the mining centre of Johannes-
burg passes through Vereeniging,
and the coal-mine, from which
the greater quantity of fuel-
supply for the railway is derived,
lies about 3 mile west of the
township.

Vol. 53.] SIGILLARIA, GLOSSOPIERIS, ETC., IN SOUTH AFRICA. 318

Two miles east of Vereeniging, and close to the junttion of
the Klip and Vaal Rivers, a sandstone-quarry was opened for the
purpose of supplying material for the construction of a bridge over
the Vaal River, and the workmen unearthed a great number of fossil
plant-remains, among which were several varieties of G'lossopteris
and fragments of a stem of Sigillaria.

These were contained in a layer of horizontal sandstone about
8 feet below the exposed surface of the bed, and about 6 feet from
the floor of the quarry. ‘This layer is laminated and somewhat
wavy in structure, whereas the beds above and below it are massive
and horizontally bedded ; the material of which they are composed,
however, is similar, fine-grained sandstone of a yellowish-white
colour, stained red in the planes of bedding.

The accompanying section (fig. 3) illustrates the principal
geological conditions at this spot, and shows the sandstones resting
unconformably upon the older tilted rocks which crop out to the
north, and are probably of Carboniferous age, the boulder-bed
representing perhaps an ancient beach-line.

Fig. 3.—Section through quarry 2 miles E. of Vereeniging.
: Molteno Beds ey

Li; Yy Yy ; Ds =

N S.

* = Layer in which Sigillaria was found.

This boulder-bed apparently continues for a great distance along
the line of outcrop of the northern edge of the Molteno Beds as well
as extending underneath them. A borehole put down some miles
to the southward, under the superintendence of Mr. A. R. Sawyer,
F.G.S., intersected both the coal-seam and the boulder-bed.

The quarry in which the fossils were found is but a few hundred
yards south of the outcrop of this boulder-bed, and there does not
appear to be any coal at this spot. In the dark shales which
underlie sandstones of similar appearance and structure, and which
were intersected in sinking the Vereeniging coal-shaft, several of the
specimens which accompany this paper were found by the writer,
and there is no doubt that they are from the same geological horizon
as those found in the quarry. The connexion between the sand-
stone at the coal-shaft and that at the quarry is distinctly traceable
on the surface.

No. 4. Zwart Koprrrzs.

At this locality, which is about 4 miles west of the Heilbron
Road railway-station and about 15 miles south-west of Vereeniging,
a few fragments of a Lepidodendron were found some years ago in a
well sunk in search of water.

314 SIGILLARIA AND GLOSSOPTERIS IN SOUTH AFRICA. [Aug. 1897,

The finder informed me that the stem was about 5 feet: long, but
unfortunately I arrived too late to secure more than a few fragments,
the best one of which is in the Natural History Museum, South
Kensington.! The strata intersected in sinking the well consisted
principally of coarse gritty sandstone lying horizontally upon
highly-contorted actinolite-schists and granite, hoth of which crop
out on the surface in the vicinity. This patch of Molteno Beds is
detached from the main body, which lies a short distance to the
eastward.

The localities enumerated above have all been carefully examined
by me, and I have come to the conclusion that the strata there
belong to the same geological horizon and are portions of the same
series, namely, the Molteno Beds, which are generally recognized as
a member of the Triassic system of South Africa.

The following is the generally accepted classification of the
South African rocks (after Dunn) :—

Voleamic Rocks <i...-.nene0 Fossils.

Cave Sandstones............ Fragments of reptilian remains and fishes.
RediBeds 5235.4. isteetec Nearly perfect reptilian remains.

Coan ccutcicaae eter eee Plants, terns, fossil wood.

(Molteno Beds).
( Ferns, reptilian remains in great abundance
Karoo Beds (Dunn) ...... | from the base to the summit, silicified wood
Kimberley Beds (Green) .{ and sedge-like plant-impressions in lower
Beaufort Beds (Schenck) .| beds. Ganoid fishes, <Atherstonia scutata
\ and others.

There is no doubt that the Molteno Beds of South Africa are
younger than the strata which contain the great abundance of
reptilian remains, and that the Vereeniging and Zwart Koppies
fossils, belonging to species generally accepted as typical of the
Carboniferous period, have been discovered in the northern portion
of these beds. ‘There are two ways of explaining this occurrence :—
Hither these plant-remains were carried into the Triassic rocks as
fossils; or species of plants hitherto looked upon as having dis-
appeared with the close of the Carboniferous period survived into
Triassic times. This latter is probably the correct interpretation of
the occurrence of Stgillarva found at the localities mentioned. The
general geology of the country gives the impression that an island
composed of Carboniferous and Devonian rocks, on which several
varieties of plants of the former period were flourishing, was
surrounded by water, in which during the Triassic period the
horizontal sedimentary deposits containing coal (Molteno Beds)
were laid down along its shores, which are now represented by the
ancient beach-line.

I submit that this occurrence of Sigzllaria in Triassic rocks is
strong evidence that: this plant, hitherto supposed to be typical of
the Carboniferous period, survived in the Southern Hemisphere
into Triassic times.

1 See Mr. Seward’s paper, p. 315.

Vol. 53.] SIGILLARIA AND GLOSSOPTERIS IN SOUTH AFRICA, 315

24. On the Association of Sici~taRtA and GLossoPpTERIs 7 SovutH
Arrica. By A. C. Sewarp, Esq., M.A., F.G.S., University
Lecturer in Botany, Cambridge. (Read March 24th, 1897.)

[Pirates XX1I.-XXTV. ]

Tue fossil plants which form the subject of this paper were for-
warded to me by Mr. David Draper, of Johannesburg, and my
thanks are due to him for affording me the opportunity of making
the following contribution to the paleobotany of the Southern
Hemisphere.

The localities' from which the specimens were obtained are
briefly described in the foregoing communication by Mr. Draper,
who expresses the view that the beds of each horizon are probably of
the same geological age, namely, the lower portion of the Stormberg
Beds of Dunn. The evidence afforded by the plants is, however,
strongly in favour of a lower horizon ; it points to a Permo-Carbon-
iferous rather than a Triassic age. The interesting association of
genera brought to light by Mr. Draper’s discoveries, and its signifi-
cance from the point of view of geological age and plant-distribu-
tion, will be best discussed after a description of the individual
species.

The following are the principal localities from which the plants
were obtained :—(1) Boschmans Fontein and Maggies Mine in the
Middelburg district, Transvaal; (2) Casey’s Township (Francis), 2
miles south of Johannesburg; and (3) Vereeniging, about 30 miles
south of Johannesburg. In a paper by Schmeisser on South African
minerals there is a reference to the occurrence of Gilossopteris and
Schizoneura in the Middelburg district at the Holfontein Colliery.
The rocks are spoken of as belonging to the Stormberg Series.’
From the second locality, under the name of ‘ Francis,’ M. Zeiller °
has recently described the following species:—Glossopteris Brown-
tana, Brongn., G. indica, Schimp., G. angustifolia, Brongn.,
Vertebraria indica, Royle, Sphenopteris (?) sp., Phyllotheca sp.,
Neggerathiopsis Hislopi (Bunb.), and two small seeds. No plants
have been described from the third locality, Vereeniging ; but in a
recent work by Goldmann on South African mines the following
passage occurs :—‘ At Vereeniging, 35 miles south of Johannes-
burg, in the Coal Measures resting unconformably on the dolomite,
in addition to many Triassic fossils, Lepidodendron and Favularia,
both unmistakable Carboniferous fossils, have been discovered.”*

* The ‘Lepidodendron’ referred to by Mr. Draper, p. 313, from Zwart Koppies
is an imperfectly-preserved Knorria-form of a Lepidodendroid or Sigillarian
plant. It is hoped, however, to describe the South African plants in the Natural
History Museum in another paper.

2 «Ueber Vorkommen u. Gewinnung d. nutzbaren Mineralien in d. Siidafrik.
Republik,’ p. 66 (Berlin, 1894).

* Bull. Soc. géol. France, ser. 3, vol. xxiv. (1896) p. 349.

4 * South African Mines,’ vol. i. p. xxiv (London, 1895-96),

316 MR. A. C. SEWARD ON THE ASSOCIATION OF [Aug. 1897,

In referring to this statement M. de Launay! has suggested that
possibly the supposed Coal Measure plants mentioned by Gold-
mann were obtained from the dolomite underlying the coal-beds.
Mr. Draper’s fossils enable us to speak with certainty as to the
occurrence of Stgillaria associated with typical members of the
Glossopteris-flora in the beds overlying the dolomite. This
discovery was recorded in a note communicated to the British
Association at last year’s meeting.”

In the following descriptive notes the collection of plants is dealt
with as a whole, and the short table at the end summarizes the
species recognized from each locality.

Genus GuLossopreris, Brongniart.

‘Prodr. Hist. Vég. foss.’ (1828) p. 54; ‘ Hist. Vég. foss.’ (1828) p. 222,
pls. Lxii. & lxiii.

This generic name was founded by Brongniart in 1828 for
certain tongue-shaped leaves from Australia and India. Other
specimens from England and Scania to which he gave the same
generic name have since been referred to distinct genera. The
Australian and Indian leaves were placed in the same species,
Glossopteris Browniana, and defined as follows*:—

‘G. foliis lanceolatis vel subspathulatis obtusis (1-2 pollicibus
latis); nervo medio valido superne canaliculato; nervulis basi
obliquis reticulatis, apice tantum simplicibus vel furcatis, marginique
subperpendicularibus, vix obliquis.’

On account of the smaller size of the Australian specimens and
their obtuse apices, they were referred to by Brongniart as G. Brown-
tana var. a australasica, while the larger and more sharply pointed»
Indian forms were designated G. Browniana var. (3 indica. Another
specific name, G. angustifolia, was chosen by Brongniart* for some
long and narrow Indian leaves with the same venation-characters
as in the former species. Brongniart’s type-specimens are in the
Paris Natural History Museum, Jardin des Plantes. Zeiller® has
recently published accurate drawings of the venation in each of.
these types, which should be consulted as more trustworthy than the
less detailed figures given by Brongniart.

In 1869 Schimper ° raised Brongniart’s var. (3 indica to the rank
of a distinct species, Glossopterts indica. After giving a diagnosis
of G. Browniana, Schimper points out that he has seen Glossopteris-
leaves on the same slab of rock varying from an oblong spathulate
to an almost linear form, and he recognizes the considerable diversity
of shape as a necessary accompaniment of difference in age. The
very large number of leaves of this genus described by Feistmantel ”

1 «Les Mines d’Or du Transvaal,’ Paris, 1896, p. 209 (footnote).

2 A. C. Seward, Brit. Assoc. Rep. (L’pool) 1896, p. 807.

3 « Hist. Vég. foss.’ p. 223 & pl. lxii. * Ibid. pl. Ixiii. fig. 1.

5 Bull. Soe. géol. France, ser. 3, vol. xxiv. (1896) pp. 363, 367, & 370.

6 «'Traité de Pal. vég. > vol. i. p. 645.

7 See ‘Fossil Flora of the Gondwana System,’ Mem. Geol. Surv. India
(Paleontologia Indica), etc.

Vol. 53.] SIGILLARIA AND GLOSSOPTERIS IN SOUTH AFRICA. 317

from different horizons in the Gondwana Series of India have in
several instances formed the types of new species founded on quite
inadequate grounds. It requires but a brief examination of Feist-
mantel’s figures and some acquaintance with the commoner forms of
Glossopteris to confirm this statement. Zeiller has recently shown
good reasons for identifying Feistmantel’s G. communis with
G. indica, Schimp.* It is not proposed at present to attempt a
general revision of the specific determinations of this Southern
Hemisphere genus of ferns, but to demonstrate the extreme diffi-
culty of drawing satisfactory distinctions between such forms as are
included under G. Browniana, G. indica, and G. angustifolia. In
1861 Bunbury ” figured and described several specimens of Gilosso-
pteris from the neighbourhood of Nagpur, Central India, and insti-
tuted some new specific names. The type-specimens of Bunbury
are now in the Museum of the Geological Society, and in the
Bunbury Collection in the Botanical Museum, Cambridge. It is
difficult, or indeed impossible, to admit the existence of adequate
erounds for some of Bunbury’s species, and he himself calls
attention to the variation in the direction and number of the veins;
he expresses the opinion that no satisfactory specific distinction can
be drawn between the Australian and Indian forms of G. Brown-
jana. Tenison-Woods,* in speaking of the variation in venation-
characters, admits that the distinctions drawn between many of
the fossil leaves are not such as would rank as specific features
in recent fern-fronds. In Zeiller’s interesting paper on African
plants, already alluded to, attention is called to the striking variation
in form and yenation exhibited by the Glossopteris-leaves. The
drawings which he gives of Brongniart’s type-specimens illustrate
in a marked degree the close agreement as regards the venation in
G. Browniana, G. indica, and G. angustifolka. In one of Zeiller’s
specimens the veins on the two sides of the midrib are by no means
identical, but exhibit a striking difference as regards the angle and
direction. While endeavouring to avoid the dangerous and un-
scientific practice of needlessly multiplying specific names, we must
be careful to bear in mind the possibility of carrying too far the
system of linking together distinct types by a long series of inter-
mediate forms. Itis no easy matter to decide as to the best course to
adopt with regard to G. Brownana, G. indica, and G. angustifolia ;
but my impression is that these three names cannot be maintained as
standing for three well-marked species of Glossopteris. Attention has
been called by several writers to the variations in both form and
venation, and an examination of similar single fronds of recent ferns
seems to demonstrate the want of a definitely fixed form among
living species. The test of size is always dangerous, and cannot as
a rule be regarded as a taxonomic character of much value. From
the widespread occurrence in Australia, Africa, and India of layers

1 Bull. Soc. géol. France, ser. 3, vol. xxiv. (1896) p. 368.
2 Quart. Journ. Geol. Soc. vol. xvii. (1861) p. 328.

3 Proc. Linn. Soc. N. S. Wales, vol. viii. (1883) p. 122.

* Op. supra cit. pl. xvii. fig. 2.

318 MR, A. C. SEWARD ON THE ASSOCIATION OF [ Aug. 1897, »

of rock formed largely of Glossopteris leaf-beds, it would seem that
vast tracts of country must have been covered with this common
genus of ferns. The fact of this very great abundance of the leaves
of a plant differing but littlein shape and venation, may afford some
confirmatory evidence in favour of including the closely similar
forms of leaves in one species. This is not, indeed, a point to be
emphasized; but the crowded state of the plants over wide areas is
not entirely favourable to the association of closely-allied species.

GiossorreRts Brown1ana, Brongn.
‘ Prodr. Hist. Vég. foss.’ p. 54; ‘ Hist. Vég. foss.’ p. 223 & pl. lxii.

Our knowledge of this species has recently been extended by the
exceedingly interesting facts and ingenious interpretations presented
by M. Zeiller in favour of the opinion that Royle’s genus Verte-
braria is the rhizome of Gilossopteris. The nature of Vertebraria,
first described by Royle in 1839," has long been a puzzle to paleo-
botanists. | Previous to Zeiller’s note published in the ‘ Comptes
Rendus’ of March 23rd, 1896, and the more complete account in
the paper previously quoted, the nearest approach to the true
explanation was that suggested by Bunbury? a propos of an
unusually good specimen which he described from Nagpur. This
specimen, now in the Geological Society’s Museum, is in the form of
a main axis of the Vertebraria-type giving off numerous branched
roots. Bunbury expressed the opinion that Vertebraria was prob-
ably the root of a plant, possibly Payllotheca, and now Zeiller has
given proof of its rhizome nature.* For another addition to our
knowledge of Glossopterts we are also mainly indebted to M. Zeiller.
Among the Glossopteris-fronds from ‘ Francis,’ near Johannesburg,
Zeiller noticed several smaller scale-like leaves having the same
anastomosing venation as the normal and larger leaves, but without
a midrib; and he was led to the conclusion that Gilossopteris Brown-
tana had two kinds of leaves. He compares the two leaf-forms
borne by the same rhizome with the large fronds and small, stiff,
scale-like appendages of Onoclea struthiopteris, Hoffm. Among some
specimens in the Bunbury Collection I have found some small leaves
without a midrib, exactly similar to those figured by Zeiller in
association with the typical leaves of Glossopteris Browniana from
the Newcastle Beds of the Hudson River, New South Wales. A small
portion of this specimen is shown in Pl. XXIII, fig. 1; ats, s’, s”
are seen three smaller leaves with slightly spreading and ana-
stomosing veins. ‘The most perfect of these leaves, s, has a length
of 1 cm. and a breadth of 6mm.; the upper surface is strongly

1 ‘T]lustrations of the Botany, etc., of the Himalayan Mountains & of the
Flora of Cashmere,’ vol. i. (1839) p. xxix.* pl. i.

2 Quart. Journ. Geol. Soc. vol. xvii. (1861) p. 339.

3 [Since this paper was read M. Zeiller’s conclusions have been confirmed by
Mr. R. D. Oldham, who has published figures and descriptions of Glossopteris-
fronds attached to a Vertebrarian rhizome, Rec. Geol. Surv. India, vol. xxx.
pt. i. (1897) p. 45.—June Ist, 1897.]

Vol. 53.] SIGILLARIA AND GLOSSOPTERIS IN SOUTH AFRICA. 319

convex, as shown more clearly in the shell-like appearance of the
specimen next to it. A comparison of these small leaves with
the scale-leaves figured by Zeiller leaves no doubt as to their
identity. Among recent ferns we may quote certain species which
show a much closer correspondence in their leaves to Glossopteris
Browniana than is afforded by Onoclea. In Drymoglossum carno-
sum, Hk.,! we have a Polypodiaceous fern in which the creeping
rhizome bears two distinct kinds of simple fronds, linear-spathulate
fertile fronds and smaller suborbicular or elliptical barren fronds.
Similarly in Drymoglossum piloselloides, Presl*; also in Acro-
stichum villosum, Sw.,? Polypodium vaccinifolium, F. & L., P. ser-
pens, Forst.,* etc., there are two distinct forms of leaves. In
P. vaccinifolium the linear leaves are fertile, and the smaller
roundish or elliptical leaves sterile; while in A. villoswm the small
suborbicular leaves are fertile. Other ferns might be named
illustrating the same kind of dimorphism as that which appears
to have characterized Gilossopteris Browniana. We are still without
satisfactory evidence as to the nature of the sori and sporangia of
Glossopteris. It is, at all events, unwise to attach any taxonomic
importance to the very doubtful examples of fertile fronds described
by Bunbury, Feistmantel, Carruthers, and others, as some authors
have done. In a recent paper by Etheridge on a Glossopteris-plant
in which several leaves are attached to a stem, undue importance
is given to the supposed systematic value of the sorus-like impres-
sions.” The specimens of Bunbury and Zeiller which I have had an
opportunity of examining, wherein there occur more or less elliptical
patches or holes in the lamina, certainly suggest the sori of a
Polypodiaceous fern, and such evidence as we have favours the
reference of Gilossopteris to this family of ferns. It must he
remembered, however, that no trace of a sporangium has so far
been seen on a Glossopteris leaf.

As bearing on this question it may be mentioned that the entire
simple leaf occasionally met with in Polypodiaceous ferns is
unknown in recent Cyatheacee and Gleicheniacez.°

In a paper by M‘Coy in 1847” there occurs a passage in his
account of some Australian leaves where he speaks of scale-like
appendages which may have been the smaller leaves described by
Zeiller in the African Glossopteris :—‘I believe I have ascertained
the rhizoma of this species, which is furnished with ovate, clasping

1 W. J. Hooker, ‘Gen. Filicum,’ pl. Ixviii. a (London, 1842); see also
R. H. Beddome, ‘ Ferns of British India,’ vol. i. pl. lv. (Madras, 1866).

* Hooker, ‘Garden Ferns,’ pl. xlvi. (London, 1862); Beddome, ‘ Ferns of
Southern India,’ ed. 2, pl. lv. (Madras, 1873).

3 W. J. Hooker & R. K. Greville, ‘ Icones Filicum,’ vol. i. pl. xev. (London,
1831).

* Hooker & Greville, op. cit. pl. xxiii.

5 This subject is more fully dealt with in an article in ‘Science Progress,’
1897, p. 178.

8 «Recherches anatomiques sur les Cryptogames vasculaires,’ G. Poirault,
Ann. Sci. Nat. [Bot.] vol. xviii. (1894) p. 113.

7 *On the Fossil Botany & Zoology of the Rocks associated with the Coal
of Australia,’ Ann. & Mag. Nat. Hist. ser. 1, vol. xx. (1847) p. 151.

320 MR. A. C, SEWARD ON THE ASSOCIATION OF [ Aug. 1897,

(or at least very convex) subcarinate scales, having a divaricating
reticulated nervation, resembling that of the perfect frond, but
much less strongly marked; these scales are of large size, some of
them being nearly an inch in length, and terminating at the apex
in a long, flat, linear appendage, about one line in width, which
occasionally gives off small, lateral, flat membranous branches
nearly at right angles...’ He compares the scales with some
ramenta figured by Fée in Acrostichum and other genera.’

DEscRIPTION OF THE SPECIMENS.
(PAG ASI phic! 13)

Portion of afrond 5 cm. long, showing distinct anastomosing and
crowded veins, with several elongated and irregular elliptical or
circular holes in the lamina. Probably these sorus-like patches
are the result of tearing; the specimen illustrates the danger of
attaching any great importance to characters of this kind In
venation and leaf-form the fragment agrees with the Australian
examples of G. Browniana seen on the piece of shale represented
in Pl. XXIII, fig. 1, and with G. Brownzana figured by Zeiller from
Francis (op. jam cit. pl. xvi. figs. 3 & 4), and I believe also with
the specimen named by this author G. angustifolia, in which there
occur what are very probably the impressions of sori. Compare
also the leaf figured by Feistmantel as G. communis var. stenoneura.”

Locality. Boschmans Fontein, Middelburg.

Pl. XXI, fig. 2. (G. Browniana var. indica.)

A small piece of a large frond; from the midrib to the leaf
margin 2°8 cm. in breadth. This fragment is of interest as
illustrating the difficulty of drawing any sharp line between
G. Browniana and G. indica. It is considerably larger than the
leaf shown in fig. 1, but the venation is of the same type. Zeiller’s
figs. 1 and 2, pl. xvii., of G. indica agree exactly with the fragment
represented in our fig. 2. It is also identical, as regards both size and
venation, with some of the large fronds described by Bunbury from
Nagpur as G. Browniana var. indica, G. stricta, Bunb., and other
species. It is impossible to recognize a distinct difference between
the numerous well-preserved fronds on the two large slabs of rock
(in the Botanical Museum, Cambridge) from which Bunbury described
his species Gt. stricta. One is able to trace a gradation, from the
large fronds referred to G. Browniana var. indica with the lateral
veins disposed as shown in Pl. XXI, fig. 2, to the fronds which
Bunbury referred to G. stricta,? in which the lateral veins are
almost at right angles to the midrib. Some of the leaves figured by

1 See Fée, ‘Genera Filicum’ (Polypodiacez), 1850-52.

2 <Plora of the Damuda & Panchet Divisions,’ Foss. Flor. Gondw. System,
Mem. Geol. Surv. Ind. (Pal. Ind.) vol. iii. (1881) p. 99 & pt Xxxil. A, fig. 3, ete.

3 Quart. Journ. Geol. Soc. vol. xvii. (1861) pl. ix. fig. 5

Vol. 53.] | SIGILLARIA AND GLOSSOPIERIS IN SOUTH AFRICA. 32)

Feistmantel from New South Wales as G. Browntana’ agree very
closely with this form of frond, at least as regards the venation.
The specimen represented in Pl. XXI. fig. 2 is from Casey’s Town-
ship (Francis).

A much larger portion of a frond, 15 cm. long and 5 em. broad,
which agrees exactly with the fragment shown in Pl. XXI. fig. 2,
has been found by Mr. Draper in the coal-beds of Maggies Mine.

PL KEI fig. 3. (G. Browniana var. indica.)

This specimen shows the venation much less clearly than those
of figs. 1 and 2, Pl. XXI. It is in the form of an indistinct
impression on sandstone, and was obtained from the same quarry
at Vereeniging as that which afforded the specimens of Sigillaria
described below. The length of the leaf is 14:5 cm., and the
broadest part measures 6 cm.; the midrib is well marked and broad,
gradually tapering towards the frond apex. The lateral veins are
very numerous, and oblique to the midrib, agreeing with those of
fig. 2, Pl. XXI.; the leaf should most probably be referred to the
same species—G. Browniana var. indica.

On the same piece of sandstone, which is practically full of
imperfect leaf-impressions and forms part of a leaf-bed, there are
several long and narrow Gilossopterzs-leaves like that from Casey’s
Township (Francis) shown in Pl. X XI. fig. 4a, also portions of Veeg-
gerathiopsis, and in one case possibly a fragment of Gangamopteris
like the large specimen of Pl. XXII. fig. 1. This form of leaf bears
a close resemblance to those named by Feistmantel ‘ Glossopteris
damudica,’ ? which it is difficult to distinguish from his G. communis
(=G. Browniana var. indica). Compare also G‘. ampla, Dana.*

Pl. XXI. fig. 4a. (G. Browniana var. angustifolia.)

Leaf imperfect; length of the portion preserved 17 cm., and
breadth about 2cm. ‘The venation agrees with that of Brongniart’s
type of G. angustifola, and indeed with G. Browniana. The
specimen figured by Zeiller as G. Browniana in pl. xvi. fig. 4 (op. cit.)
bears a close resemblance to this specimen, which is from the same
locality. Several smaller and less perfect specimens of this form of
leaf have been found in the sandstone at Vereeniging in the beds
containing Sigillaria, and in one or two of these impressions the
broader basal part of the short petiole is clearly shown. In cases
where these narrow leaves do not show the apical portion, it is
possible to mistake the long and narrow basal portion of alarge leaf
of G. Browniana var. indica for an almost complete linear leaf. The
example shown in fig. 4 and some of the impressions from

1 Mem. Geol. Surv. N.S.W., Palzxontology No. 3 (1890), pls. xvii., xx. ete.

2 «Flora of the Damuda & Panchet Divisions,’ p. 105 & pls. xxx. A, xxxi. A, ete.

3 For example, a specimen figured by Jack & Etheridge in their ‘Geology
& Palzontology of Queensland and New Guinea,’ pl. xVi. fig. 7 (Brisbane,
1892).

Q7s.G.5. No. 211. : Z

322 MR. A. C. SEWARD ON THE ASSOCIATION OF [ Aug. 1897,

Vereeniging are,. however, almost certainly portions of long and |

narrow leaves. In specimens from the leaf-heds of both Australia
and India it is possible to trace a gradual alteration in leaf form
from the narrow linear type to the much broader spatulate or
elongate-oval form ; this is well seen in specimens in the Bunbury
Collection, which includes Australian (Newcastle Beds) and Indian
examples of Glossopteris-leaves. It is in any case convenient to
designate the long narrow fronds by some distinctive term,
but we have not, I believe, sufficient evidence to justify the
use of a distinct specific name; for this reason I propose te speak
of such fronds as G. Browniana var. angustifolia.

Several specimens of Vertebraria (Gilossopteris-rhizome) have
heen found at Casey’s Township (Francis), but the pieces sent by
Mr. Draper are not so well preserved as those figured by Zeiller
from the same beds. The largest example in the Draper collection
is one from Vereeniging, which has a length of 10 em., and
shows the characteristic transverse markings which have recently
been cleverly interpreted by Zeiller.

Naeeeratuiopsis Hrstopr (Bunb.).

Quart. Journ. Geol. Soe. vol. xvii. (1861) p. 334, pl. x. fig. 5.

The generic name Neggerathiopsis was proposed by Feistmantel
in 1879? for certain leaves previously referred by Bunbury to
Neggerathia. The precise nature of this plant is still undecided,
and the fragments obtained in the Transvaal do not add anything
of botanical importance to our previous knowledge.

Pl. XXI. fig.46. This basal leaf-fragment, 5 cm. in length, agrees
exactly with the specimens described by Zeiller from the same
locality. In another specimen from Casey’s Township (Francis)
there are two tapered portions of Jeaves lying parallel to one
another, and in such a position as to suggest the attachment of
two pinne to a rachis; but the bases are not seen, and it is equally
possible that their position may be entirely accidental. Imperfect
impressions of what are most probably Naggerathiopsis-leaves occur
in association with the Sigi/laria at Vereeniging.

Locality. Casey’s Township (Francis).

Pl. XXI. fig. 6. In this specimen there is a portion of a leaf
seen at a, with a strongly convex surface and narrow base; the
upper portion is torn across irregularly at v. The surface-features
are not very distinct, but the leaf is traversed by parallel or slightly
spreading veins which appear to fork occasionally and possibly
anastomose, although it is very difficult to follow accurately their
course owing to imperfect preservation. Above the broken distal
end «, and at a lower level on the rock, there are two slightly
concave impressions of Glossopteris-leaves at g and g'. In both

1 ¢Blor. Talchir-Karharbari Beds, Foss. Flor. Lower Gondw.,’ Mem. Geol.
Surv. India, Palzontdlogia Indica, vol. ii. (1879) p. 23.

Vol. 53.] SIGILLARIA AND GLOSSOPTERIS IN SOUTH AFRICA. 323

leaves g and g' the oblique anastomosing veins may be readily
distinguished, but as the two fragments le in different planes the
veins are not clearly shown in the photograph. The whole specimen
is by no means clear ; it is possible that we have simply an accidental
association of what appears to be a portion of a Maggerathiopsis-
leaf with two leaves of Glossopteris. On the other hand, the
relative positions of the leaf a and the leaves g and g’, and the fact
that we have only half the breadth of the lamina in each of the
Glossopteris-leaves, suggest the possibility of a torn scale-leaf
(a) covering partially-expanded Gilossopteris-leaves. The imper-
fection of the specimen precludes the expression of any very decided
opinion as to its nature.
Locality. Boschmans Fonte, Middelburg.

GANGAMOPTERIS CYCLOPTEROIDES, Feistm.
Feistmantel, Rec. Geol. Surv. India, vol. ix. (1876) pt. iii. p. 73.
(Pl. XXII. fig. 1, and text-fig. le, p. 324.)

The specimen shown in Pl]. XXII. fig. 1 1s an imperfect impression
on a slab of iron-stained sandstone from Vereeniging. It measures
10 em. in length, and is about 6 cm. broad; the form is obovate or
broadly oval. The veins spread from the narrow basal portion in a
flabellate manner, and along the median line they are almost
vertical ; the details are not at all clearly seen on the sandstone-
surface, but there appear to be indications here and there of lateral
anastomoses. The form and general appearance of the leaf remind
one of the European genus Psygmophyllum figured by Lindley
and Hutton’ from England as Neggerathia flabellata, by Schmal-
hausen? from Russia, etc. A comparison may also be made with
Rhipidopsis ginkgordes, Schmalh., and Palcoutttaria Kurtzi, Feistm.
Among Southern Hemisphere fossils, some of the Indian leaves
figured by Feistmantel as Gangamopteris cyclopteroides * agree fairly
closely with the present specimen, which may probably be referred to
that species. The same author has also figured a very similar leat
from near Kimberley.*

The smaller leaf (4-8 cm. long) represented in text-fig. 1¢ (p. 324)
is from the shales of Casey’s Township, and is probably an example
of the same species.

1 «Foss. Flor.’ pl. xxix.

2 «Die Pflanzenreste der Artinskischen und Permischen Ablagerungen im
Osten des Europaischen Russlands,’ Mém. Com. géol. vol. ii. (1887) no. 4, pl. iii.
Compare also Baiera gigas, Schmalh., pl. v. fig. 10.

The resemblance between certain forms described by Schmalhausen and
some of the types of the Glossopteris-flora is a matter of considerable interest,
and has been recently discussed by Zeiller, Bull. Soc. géol. France, ser. 3,
vol. xxiv. (1896) p. 466. See also Schmalhausen, Mém. Acad. Imp. Sci. St.
Pétersb. ser. 7, vol. xxvii. 1879. ,

3 «Foss. Flor. Talch.-Karh.,’ Pal. Ind. vol. iii. (1879) pl. xxvii. fig. 1, ete.

* «Uebersichtliche Darstellung der geol. u. pal. Verhaltnisse Siid-Afrikas, pt. i.
(1889) pl. iv. fig. 2, Abh. k. Bohm. Ges. Wiss. vol. iii. [vii.]. See reference
to the determination of the specimen by MM. Zeiller & Renault.

z2

324 MR. A. C. SEWARD ON THE ASSOCIATION OF [ Aug. 1897

C
a, Sphenopteris sp. XO. c. Gangamopteris cyclopteroides, :
b. S. ? Sigillaria sp. G. Glossopteris Feistm. Slightly enlarged.
sp. Nat. size. d. Cardiocarpus sp. X93.

Equisetaceous Stems.
PayiLoranca sp. “(Pl XOX. ties 1)

This photograph shows one of the large and well-preserved
impressions of a stem from Maggies Mine, It is 16 cm. long and
nearly 4 cm. broad, the internodes having a length of about 4 em.
The surface shows narrow, prominent ridges, separated by broad, flat
depressions, which do not alternate at the nodes, but are continuous
from one internode to the next, as in Phyllotheca and Schizoneura.
Several specimens of smaller stems identical in form with this
larger example have been found at the same locality. In the
absence of leaves it is perhaps unwise to refer the specimens to a
particular species, but the stems agree very closely with those

Vol. 53.] SIGILLARIA AND GLOSSOPTERIS IN SOUTH AFRICA. 325

figured by Feistmantel as Schizoneura gondwanensis, Feistm.,’ from
the Lower Gondwanas. There is, however, a close resemblance
between the African stems and the specimens of Phyllotheca
australis figured by Feistmantel* from the Newcastle Beds of New
South Wales. See also the specimen figured by Bunbury as
Phyllotheca indica, Bunb.,’ from Central India, Ph. Hookeri, M‘Coy,
figured by M‘Coy* from New South Wales, and Phyllotheca sp.
described by Schmalhausen from Russia.’

In the absence of leaves it would seem impossible to define the
distinctive characters for Phyllotheca -and Schizoneura. The
comparison of several leaf-bearing stems of these two genera leads
one to express the opinion that possibly the retention of both
generic names may be unnecessary. Some exceedingly interesting
specimens of Phyllotheca from Heraclea,° which I have recently had
the opportunity of examining through the kindness of my friend
M. Zeiller, appear to throw some further light on the affinity of
this genus ; but this question will be dealt with by M. Zeiller in his
description of the new material.

Fossils of doubtful Affinity.

Pl. XXII. fig.45. This long, finely-ribbed specimen has a length
of 27 cm. and a breadth of 5°50 cm. The ribs, separated by very
narrow grooves, have a breadth of about 1 to 1:8 mm., and there
occasionally occurs a less distinct groove traversing the middle of
some of the ridges. Towards the narrower end theribs are slightly
narrower and the stem is somewhat curved, in a manner suggesting
an approach to the point of attachment. There is no absolutely
certain indication of a node; the irregular transverse lines at « x
are no doubt casts of accidental cracks, but near the upper and
broader part of the specimen there is an indistinct transverse line
which may be the impression of a feebly-marked node. It is not
easy to decide in the case of a fossil such as this between a broad
parallel-veined leaf and a flattened stem with long internodes. In
the present example there are no indications of forked veins or of
lateral anastomoses between the veins. Thereisa close resemblance
between this fossil and some of the larger Cordaites-leaves from the
European Coal Measures. The still larger parallel-veined leaves
described by MM. Renault & Zeiller as 7%tanophyllum might well
be mistaken for stems. One may compare their figures in pl. lxix.
of the ‘Commentry Flora’’ with the present doubtful fossil. On
the whole, however, I am disposed to refer the specimen to some

1 « Flora of the Damuda & Panchet Divisions,’ pl. ix. a. fig. 7, pl. v. A, ete.

2 Mem. Geol. Surv. N.S.W., Paleontology No. 3 (1890), pl. xiv. fig. 5.

3 Quart. Journ. Geol. Soc. vol. xvii. (1861) pl. xi. fig. 1.

* M‘Coy, Ann. & Mag. Nat. Hist. ser. 1, vol. xx. (1847) pl. xi. fig. 7.

° Schmalhausen, Mém. Acad. Imp. Sci. St. Pét. ser. 7, vol. xxvii. (1879) pls. i.,
ix., ete.—The rocks spoken of by Schmalhausen as Jurassic are probably
Permian: see Zeiller, Bull. Soc. géol. France, ser. 3, vol. xxiv. (1896).

6 See note by Zeiller in the Compt. Rend. vol. exxii. June 4th, 1895.

7 *Plor. houill. Commentry,’ Atlas Soc. Industr. Minér. 1890, pl. lxix.

326 SsIGILLARIA AND GLOSSOPTERIS IN soUTH AFRICA. [Aug. 1897.

Equisetaceous plant. It is possible that it may be the impression
of a Calamite, such as C. ramosus, Brongn., as figured by Weiss,’ but
the evidence hardly justifies the reference to this genus.

Pl. XXIV. fig. 2. This figure represents a portion (7:5 cm.) of
a long cast of a stem, 26-5 cm. in length and 2 cm. broad. In the
part seen in the figure there is a prominent transverse ridge at n,
which no doubt marks the position of a node. The transverse
ridge may represent the prcjecting zone of wood which characterizes
the nodal region of a Calamitean stem, but the exact nature of the
specimen must be left doubtful. )

SIGILLARIA Braropr (Brongn.).
Brongniart, ‘Class. Vég. foss.’ (1822) p. 22 & pl. 1. fig. 5.

(Pl. XXITI. fig. 2 & Pl. XXII. fig. 3. Also text-figs. Za-p, p. 327
and 3, p. 329.)

At the British Association Meeting at Liverpool in 1896, I commu-
- nicated a short note to the Geological Section ‘ On the Discovery of a
Lepidodendroid or Sigillarian Plant by Mr. Draper in the Sand-
stone of Vereeniging, associated with some Typical Members of the
Gilossovteris-flora.’ A more complete examination of the specimens
has left no doubt in my mind that at least most of the casts are
those of Srgillaria, and in all probability specifically identical with
the well-known S. Brardi. My friend Mr. Kidston, who saw the
specimen exhibited at Liverpool, expressed himself in favour of Szgil-
laria rather than Lepidophloios, as was suggested in my preliminary
note. M. Zeiller has also seen the best specimen and agrees with
the reference to Brongniart’s species of Szgillaria. A comparison
of the specimen shown in. Pl. XXIII. with the type-specimen of S2gil-
laria Brardi in the Paris Natural History Museum * confirmed me
in the above identification.

The specimen of which the greater part is seen in Pl. XXIIL. fig. 2
measures 18°5 cm. in length, and about 12 cm. in breadth ; it is in the
form of a fairly well-marked cast on sandstone of a stem covered with
closely-set and spirally-disposed leaf-scars. ‘The leaf-scars are about
9 mm. in breadth and 7 mm. in height ; they do not afford an exact
reproduction of a surface-view of the stem, but represent a cast
of the surface of a stem in which decay had already removed
a small amount of some of the less resistant tissues. Instead
of the three characteristic marks on each leaf-scar—the small
round central scar of the leaf-trace bundle with a larger and
slightly curved scar on either side—we usually find in their place an
obliquely sloping sandstone-projection from the upper third of each
scar. The nature of the cast of each leaf-scar will be more clearly
understood from the enlarged drawings in fig. 2, described below.

1 «Steinkohien-Calamarien,’ Abhandl. k. Preuss. geol. Landesanst. vol. v.
(1884) pt. ii. Atlas, pls. v., vi., & vil.

* Compare Brongniart’s figure in his ‘Class. Vég. foss.’ pl. i. fig. 5 ; also in ‘ Hist.
Vég. foss.’ pl. elviii. fig. 4. Compare also Germar’s figures of S. Brardi in
‘Die Verstein. Steinkohlgeb. Wettin u. Lobejin,’ fasc. ii. pl. xi. (Halle, 1849,
etc.).

a-e= Sigillaria Brardi (Brongn.).

x3.

f=? Sigillaria sp.

Ds

328 MR. A. C. SEWARD ON THE ASSOCIATION OF [Aug. 1897,

In Pl. XXIII. fig. 2 each leaf-scar is more or less completely sur-
rounded by a narrow sloping plate of sandstone with an irregular
margin. This is the last of the grooves which separated the leaf-
scars from one another on the stem-surface.

In text-fig. 2¢ (p. 327) a single scar of the stem reproduced in
Pl. XXIII. fig. 2 is drawn on a larger scale. The scar measures
6 mm. from a to 6, and 8°5 mm. frome to d. At p, p are two slight
elliptical depressions, and at ¢ a small and laterally elongated scar ;
the two former represent the familiar oval scars which are character-
istic of Sigillarian and Lepidodendroid leaf-scars, the latter (¢)
represents the scar of the leaf-trace bundle. The meaning of the
lower V-shaped prominence (') will be more easily explained after
an examination of other leaf-scars, and a brief reference to the facts
of internal structure in Lepidodendroid stems. The occurrence of
the three small marks on the leaf-scars of Sigillaria has long been
known, but their precise relation with the internal structure has only
recently been explained. The smaller middle mark has been
recognized for some time past as that of the leaf-trace bundle, and
the two larger lateral marks have been described as lateral lacune: *
consisting of strands of thin-walled and large-celled tissue. Much
additional light has, however, been thrown on the structure of these
tissue-strands by the investigations of Williamson, Bertrand, and
Hovelacque.* Williamson published a detailed account of the struc-
ture of these tissues in the case of Lepidophloios and Lepidodendron
Harcourti.? He found that the vascular tissue of the leaf-trace is
surrounded by a sheath of delicate parenchyma as it passes through
the outer cortical tissues of the stem ; in traversing the prosenchyma-
tous zone of the cortex which is situated immediately internal to the
leat-bases, the trace is found to be accompanied by a distinct strand
of fairly large parenchymatous cells. Soon after leaving the
prosenchymatous cortical zone, this parenchymatous strand, which
Bertrand has named the parichnos,’ bifurcates, and the two arms
bend away right and left of the leaf-trace, finally coming to the
stem-surface as two strands, one on either side of the outgoing
leaf-bundle. The two lateral marks are therefore the ends of the
two short arms of the parichnos. It has been suggested that
the parichnos consists of glandular tissue, and that it may
serve as ‘ transpiration-strands.’’ Its precise physiological signi-
ficance is, however, still a matter of doubt.

' See I. Felix, ‘Untersuch. uber d. inneren Bau Westfalischer Oarbon-
Pflanzen,’ Abh. k. Preuss. Geol. Landesanst. vol. vii. (1886) pt. iii. pl. 1. Also
Renault & Grand’ Eury, ‘ Rech. sur les Vég. silic. d’Autun,’ Mém. Acad. Sci.
vol. xxii. pl. i.

«Recherches sur le Lepidodendron selaginoides, Sternb.,’ Mém. Soc. Linn.
Normandie, vol. xvii. (1892).

? «On the Organization of the Fossil Plants of the Coal Measures,’ pt. xix., Phil.
Trans. vol. clxxxiv. B (1893). Several figures are given illustrating the structure
of the leaf-trace and accompanying tissues: some of these are drawn in an
inverted position.

* «Remarques sur le Lepidodendron Harcourtii, Trav. et Mém. Facult.
Lille, vol. 11. (1891) Mém. 6, p. 84.

° H. Potonié, Ber. Deutsch. bot. Gesellsch. 1893, p. 325.

Vol. 53.] SIGILLARIA AND GLOSSOPTERIS IN SOUTH AFRICA. 329

This short account of the parichnos and leaf-trace may render
easier the interpretation of the appearance presented by the leaf-scars
of the Atrican stem. In the scar shown in text-fig. 2 ¢ (p. 327), I
regard the V-shaped projection p' as the cast of the parichnos at
that point where the two short arms have united into asingle strand
which accompanies the leaf-trace for a short distance through the
outer cortex.’ The two marks p, p represent the ends of the arms.
The leaf-scars seen in fig. 2 a show the shape very clearly, also the
almost complete absence of any leaf-cushions. Atp p there is faintly
seen the cast of the parichnos-arms, and lower on the leaf-scars
the prominent cast of the fused arms of the parichnos. In fig. 26
the crescent-shaped parichnos-cast is very prominent, with a pro-
jecting knob above it, having a small hole in the centre ; this is also
seen in fig. 2d. The central
hole may represent the posi- Fig. 3.—Sigillaria Brardi (Brongn.).
tion of the harder and more Nat. size.
durable elements of the leaf-
trace, and the surrounding.
sandstone may be the cast of
the cylindrica] cavity which
resulted from the decay of the
delicate parenchyma accom-
panying the leaf-bundle. In
fig. 2d the uppermost scar 6
is probably that, of the ligule.
In fig. 2c the cast of the
parichnos is clearly seen as
a grooved trough-like struc-
ture containing the cast of
the leaf-trace t. The thin-
walled parenchyma of the
parichnos and the delicate
cells immediately surrounding
the leaf-trace would naturally
decay more readily than the
harder tissues, and the de-
pressions or cavities so pro-
duced being filled in with
sand have given rise to the
appearance presented by the
stem shown in Pl. XXIII.
fig. 2. If the above interpretation is correct, we have an interesting
example of the aid afforded by a knowledge of internal structure
towards the explanation of special features exhibited by structureless
casts.

_ The other specimens of this stem agree in most respects with that
represented in Pl. XXIII. fig. 2. In some of the casts the surface

_ | The crescent-shaped projection shown in a leaf-scar in one of Brongniart’s
figures of Sigilaria Menardi (‘ Hist. Vég. foss.’ 1828, pl. elviii. fig. 6 a) is possibly
the cast of the parichnos.

330 MR. A. C. SEWARD ON THE ASSOCIATION oF [ Aug. 1897,

with the leaf-scars is partially overlain by a comparatively thick
layer of sandstone, which is marked by numerous fine longitudinal and
transverse lines. This is no doubt the cast of some deeper-lying
tissues, either the wood or the regularly-disposed tissue of the outer
cortex. ;

In text-fig. 3 (p. 329) a small piece of a stem is shown in which the
leaf-scars are clearly seen at A; at B the cast presents a Anorria-
like appearance: the somewhat irregular elongated projections no
doubt represent the casts of elliptical spaces, left in the cortical
tissue of the stem after the decay of the delicate tissue accompanying
the outgoing leaf-bundles.

Turning to Pl. XXII. fig. 3, we have a very imperfect cast of a
stem with smaller leat-scars, and, as in the larger specimens, without
any leaf-cushions. It is impossible to attempt an exact specitic
identification of so indistinct a cast, but it is probably a smaller form
of Srgillaria Brardi, or at least it may be referred to that species.
It bears a fairly close resemblance to a specimen which Grand’ Kury
has described from the Gard as an example of Sigillaria Grasiana,
Brongn.*

? SIGILLARIA Sp.
(Pl. XXII. fig. 4a & Pl. XXIV. fig. 3; text-fig. 2 f, p. 327.)

In Pl. XXII. fig. 4@ there is a fairly well-marked impression,
reduced about one-half in size, of a stem-surface covered with leaf-
cushions which in a few places show the outlines of a leaf-scar. Part
of the same specimen is shown nearly natural size in Pl. XXIV. fig. 3.

In text-fig. 2f (p. 327) one of the best leaf-cushions is drawn on a
larger scale, showing the leaf-scars. The preservation is too imperfect
to allow of a more detailed description, and one cannot feel quite
certain as to the true affinities of the stem. The cushion shown in
fig. 2f has a breadth of 7mm. In certain forms of stems it is not
an easy matter, indeed in badly-preserved specimens it is an impossi-
bility, to distinguish between Sigillaria and Lepidodendron. In the
specimen shown in Pl. XXII. fig. 4 a, the outlines of the leaf-cushions
are fairly distinct, but it is only in a few places that the leaf-scars
can be made out; the mvure minute surface-features cannot be seen.
There is a certain amount of resemblance between this impression
from Vereeniging and those of Lepidodendron Pedroanum (Carr.)
from Brazil,” but it would be unwise to press the agreement too far.
The slightly enlarged drawing in fig.2 f shows the leaf-scar to be
much smaller than that of Sigdlaria Brardi (Pl. XXIII. fig. 2); the
leaf-cushion,on the other hand, is much larger. This difference in the
size of the leaf-cushion is, however, not a character of essential impor-
tance as regards a comparison with S. Brardi. It has been clearly
shown by Weiss’ and Zeiller * that in stems of the S. Brardi type there

1 «Bass. houill. Gard,’ pl. x. fig. 11.

2 Zeiller, Bull. Soc. géol. France, ser. 3, vol. xxiii. (1895) pl. vill.

3 Zeitschr. Deutsch. geol. Gesellsch. vol. xl. (1888) p. 565; also Weiss &
Sterzel, Abh. k. Preuss. geol. Landesanst. 1893, p. 89.

+ Bull. Soc. géol. France, ser. 3, vol. xvii. (1889) p. 603.

Vol. 53.] SIGILLARIA AND GLOSSOPTERIS IN SOUTH AFRICA. 331

is very considerable variation as regards the proximity of the leaf-scars
and the size of the leaf-cushions. In Weiss’s paper on this subject
he gives a figure of a single cushion and scar of a form spoken of as
Sigillaria wettinensis, Weiss,! which cannot be separated specifically
from S. Brardi; in this form the leaf-cushion is well marked and
prominent, and the relative size of the leaf-scar and cushion agrees
closely with that shown infig. 27. If this specimen were, however,
specifically identical with that shown in Pl. XXIII, we should expect
a greater equality in the size of the leaf-scars. On the whole I
incline towards the view that this impression may be that of a
Sigillaria, but the preservation is too imperfect to admit of any accu-
rate determination. A comparison of Pl. XXII. fig. 4 a, Pl. XXIV.
fig. 3, and text-fig. 2f with such a drawing as that given by Potonié
of Lepidodendron Volkmannianum, Sternb.,? shows a very close
agreement. This species, however, characterizes a much lower
horizon than that at which Sigillaria Brardi is usually found.

The same piece of rock as that on which this Lepidodendroid im-
pression occurs contains several fragments of Glossopteris, one of
which is seen in Pl. XXII. fig. 4 at c, and on a larger scale in
text-fig. 1b at G (p. 324).

In the important posthumous monograph by Weiss,’ completed
by Sterzel, the name Sigillaria mutans, Weiss, is adopted as the
designation of a specific type which includes a very great variety
of forms. In this species Sigilaria Brardi, S. wettinensis, and nu-
merous other examples of both Leiodermarian and Clathrarian forms
are included. ‘The reasons advanced by Weiss for the substitution
of the specific term mutans for such well-marked types as Brardi
and others are hardly convincing. The imperfect specimen from
Vereeniging bears a very close resemblance to S. mutans forma
Brardi var. sublevis figured by Weiss & Sterzel in their pl. xvi.
Compare also S. mutans forma wettinensis var. convexa (pl. xl);
and S. mutans forma urceolata (pl. xii1).

Conrres sp. (Pl. XXII. fig. 2.)

Sternberg, ‘ Flor. Vorwelt,’ fase. iii. (1823) p. 36 ; Seward, Cat. Mesozoic Plants
Brit. Mus., Wealden Flora, vol. ii. (1895) p. 113.

This specimen, 2 cm. in length and 1 cm. broad, occurs on the
same slab of sandstone as the Gangamopteris-leat of Pl. XXII. fig. 1.
The surface shows several distinct four- to six-sided areas, measuring
2 mm. in length and from 1 to 1°5 mm. in breadth, which appear
to be the proximal ends of thick scales which expanded distally, as
seen on the sloping side of the fossil at s. The proximal ends appear
to be solid; the fractured appearance of a few of the areas is
probably accidental, and does not indicate originally hollow scales.
Had the scales been hollow, the specimen would have presented a

' Zeitschr. Deutsch. geol. Gesellsch. vol. xl. (1888) p. 569. (Included by
Weiss in a later work as a ‘form’ of S. mutans, Weiss.)

? Abh. k. Preuss. geol. Landesanst. n. s. pt. xxi. (1896) p. 43, fig. 43.

3 * Die Sigillarien der Preuss. Steink. Roth. Gebiete,’ pt. ii., Weiss & Sterzel,
Abh. k. Preuss. geol. Landesanst. n. s. pt. ii. (1893).

332 MR. A. C. SEWARD ON THE ASSOCIATION OF _[ Aug. 1897,

close agreement with an Araucarian cone, and itis still possible that
it may represent a number of Araucarian scales detached from a
broad central axis and seen from the inside. The distally-expanded
portions of the scales are opposed toa reference to an Equisetaceous
strobilus. On the whole, the specimen is probably a portion of some
Gymnospermous cone, either Cycadean or Coniferous, and may be
referred provisionally to the genus Convtes.
Locality. Vereeniging.

SPHENOPTERIS sp.

Text-fig. la (p. 324). This small fragment of a leaf with a lobed
lamina and forked lateral veins is in all probability a piece of a
Sphenopteris-frond. Zeiller figures a fragment from the same
locality (Casey’s Township, Francis), which he refers to this genus,
but probably it is specifically distinct from the present example.
The piece is too small to admit of specific identification.

CARDIOCARPUS sp.

Text-fig. ld (p. 324). This solitary example of a seed among the
fossils sent by Mr. Draper was found on splitting open a small piece
of shale from Casey’s Township (Francis). It measures 9 mm. in
length, and 6°5 mm.in breadth. When first seen there was a loose
thin lamina of coal marking the position of the seed, occupying
the slightly depressed area faintly indicated in the drawing, The
broad carbonaceous margin surrounding the oval central -region
is interrupted at the base by what appears to be a canal leading
to the base of the seed. Several examples of fossil seeds from
Paleozoic rocks have been figured by different authors which show
a close resemblance to the specimen from Francis. Reference
may be made to Samaropsis sp.’ figured by Feistmantel in his
supplement to the ‘ Flora of the Talchir-Karharbdri Beds ;) Cardio-
carpus nervosa, Kidst.2; Samaropsis affinis, Schk., from the Coal
Measures of China,*? Samaropsis fluitans, Weiss,* from the Upper
Ottweiler Beds; Cardiocarpus simplex, Lesq.,’ from the Carboniferous
of North America, etc. The specimen is no doubt a Gymnospermous
seed, of that particular type placed by some authors in the genus
Samaropsis. Schimper includes certain seeds of this form under
Brongniart’s comprehensive term Cardiocarpus,° and this is probably
the wisest course to adopt. In dealing with detached portions
of plants such as seeds or cones, it is better to use compre-
hensive generic terms rather than to make use of names instituted

1 «Flor. Talch.-Karh.,’ Pal. Ind. vol. iii. (1879) pl. xxviii. fig. 8

2 Proc. Roy. Phys. Soc. Edinburgh, vol. xii. (1894) pl. v. figs. 8-5. (It is not
intended to suggest that there is a possibility of specific identity between this
and other examples quoted and the seed represented in fig. 1d; but the
references may serve to illustrate the wide distribution of this form of seed.)

3 Richthofen’s ‘China,’ vol. iv. (Schenk) pl. xliv. p. 213 (Berlin, 1883).

4 ¢ Foss. Flor. d. jiingst. Steinkohl. u. Roth. im Saar-Rheingebiet,’ pl. xviii.
figs. 24-30 (Bonn, 1869-1872).

® Second Geol. Surv. Pennsylvania (1879), ‘ Coal Flora,’pl. lxxxv. figs. 48-50.
‘Traité de Pal. vég.’ vol. 111. (1869) p. 567.

for}

Vol. 53.]° SIGILLARIA AND GLOSSOPTERIS IN SOUTH. AFRICA. 333

on the grounds of very slight differences in form. As Schenk! has
pointed out, the wide margin surrounding the central oval seed is
the impression of a fleshy seed-coat and not a membranous wing,
as many authors have termed it. The researches of Brongniart *
amd Williamson ? and others have enabled us to correlate the various
forms presented by fossil seed-impressions and casts with the tissues
of the seed and seed-coat. The canal at the base of the seed in
fig. 1d no doubt marks the position of the chalazal vascular bundle.

Fossil of doubtful Affinity. (Pl. XXI. fig. 5.)

This imperfect leaf, 3-8 cm. in length and 7 mm. broad, cannot be
referred with certainty to a particular genus. Its convex surface is
traversed by a number of parallel veins; at the apex it terminates in a
sharp, narrow point, but the base is very imperfectly preserved. The
form of the leaf suggests a comparison with the incomplete example
represented in Pl. XXI. fig. 6. A leaf such as this, especially if
imperfect, might belong to various genera, and in the case of a
single specimen it is better to refrain from any attempt at exact
identification. It may be compared with a small example of
Cordaites, C. lancifolius, Schmal., figured by Schmalhausen* from
the Permian rocks of Russia. On the other hand, certain Cycadean
pinnee or the broad leaves of such a Conifer as Araucaria or Agathis
afford close parallels with this type of leaf.

Locality. Casey’s Township (Francis).

The following table shows the distribution of the plants in
Mr. Draper’s collection among the three localities, Francis or
Casey’s Township, Boschmans Fontein and Maggies Mine, and
Vereeniging : —

Gasew? Boschmans
asey's :
T 5 Fontein & as
Township Masci Vereeniging.
F ; Maggies
(Francis). Mine
Glossopteris Browniana ............ GA wy fee x
G. Browniana var. indica ......... x < x
G. Browniana var. angustifolia ... Be CM Whig § ada x
VED ECURDIUG Y oo0 vos ns ned yeac cass sine! wee x x x
Neggerathiopsis Hislopi ..........+. x xe Se
Gangamopteris cyclopteroides ...... CaS in Oran Re Eee ne
UU OTNCLD ak sat stat aatteatotse« nap) . (\ kanes’ x
? Equisetaceous stem, cf. Calamites, = ...... | sean x
OU OMIUOSD cu dnckotes.eteuncscatleecl Gy ttecéol | | | mesows x
SO OTID GOTO (tain ay as acct tel by wads swe- Se 1. 9. pmmitek x
STIPE Ser ae wilinen yeh dene GU Ay Wewsciignc® wiih ys sniane x
COTAINCOT BUS BPs. cueeiinds «oniba conia oe x
SELLE DELCTIS SIs, sens ancavalenisiessr x |

{

1 Zittel’s ‘Handbuch der Palaontologie,’ pt. ii. p. 249 (Munich & Leipzig,
1890).

2 « Recherches sur les Graines silicifiées,’ pl. xiii. fig. 1, etc. (Paris, 1481).

3 ‘Organ. Foss. Plants Coal Measures,’ pt. viii., Phil. Trans. vol. elxvii: (1877).

* Schmalhausen, Mém. Com. géol. vol. ii. (1887) No. 4, pl. vi. fig. 2.

334 MR. A. C. SEWARD ON THE AssociaTIon oF [ Aug. 1897,

Conclusions.

Tt remains for us to consider the probable geological horizon
indicated by this assemblage of plants.

In discussing this question in the case of the Francis beds,
Zeiller} decides in favour of assigning the plant-beds to the horizon
of the Beaufort stage, which he speaks of as Permo-Triassic, and
correlates them with the Damuda Beds of India. The absence of the
genus Gangamopteris is quoted by Zeiller as indicating the upper
rather than the lower division (Barakar) of the Damudastage. This
genus has, I believe, now been recognized at Francis (fig. 1c, p. 324),
and this makes it possible to correlate the Francis plant-beds with
the Lower or Middle Damudas. The plants from Francis are on the
whole indicative of a Permo-Carboniferous age. The agreement of
the plants is closer with the Damuda flora than with that of the
underlying Karharbdri stage or the overlying Panchet Beds.

The plants from Boschmans Fontein and Maggies Mine are not
sufficiently numerous to afford very conclusive evidence, but they do
not offer any obstacle to the correlation of these rocks with those
of Casey’s Township (Francis), which Draper considers to be of the
same geological age.

We turn next to the sandstones and leaf-beds of Vereeniging,
which present the most interesting problem on account of the occur-
rence of Sigillaria.” The occurrence of Gangamopters points to the
Damuda or Karharbari stage of India as the probable representative
of the Vereeniging beds. The abundance of the long and narrow
Glossopteris-leaves, which I have spoken of as G. Browniana var.
angustifolia, would seem to point rather to the Damuda than to the
Karbarbdri horizon; but this is by no means conclusive evidence.
Draper considers these beds to belong to the same horizon as those
of the other two localities. We must next consider the relation
of the Vereeniging rocks to those of other countries in which
Sigillaria Brardt occurs.

In Europe Sigillaria Brardt usually characterizes an Upper Coal-
Measure or Permian horizon. Kidston has recorded this species
from the Middle as well as from the Upper Coal Measures of.
Staffordshire,’ but as a general rule it is a distinctly Upper Coal-
Measure and Permian form. Sitgillaria Brardi has been recorded
from the following, among other, European localities :—The Upper,
Middle, and Lower Coal Measures of England; the Commentry *
Coalfield of France, referred to an Upper Coal-Measure age,
and as characteristic of the upper beds of the Gard” Coalfield.

1 Bull. Soc. géol. France, ser. 3, vol. xxiv. (1896).
2 Molengraaff speaks of a specimen of Sigillaria from some coal-beds in the
Tyansvaal, but does not describe it: see Neues Jahrb., Beilage, vol. ix. (1894-95)
5 A
Ps Proc. Roy. Phys. Soc. Edin. vol. xii. (1894) p. 252, & Trans. Roy. Soe.
Edin. vol. xxxvi. pt. i. (1891) p. 84. See also Zeiller, Bull. Soc. géol. France,

ser. 3, vol. xxii. (1895) p. 496.
4 «Rtudes sur le Terrain houiller de Commentry,’ Flor. Foss. Renault &

Zeiller, p. 539 (1890). ; §
6 Grand’ Eury, ‘Géol. & Pal. Bass. houill. Gard,’ p. 250 (St. Etienne, 1880)

Vol. 53.] | SIGILLARIA AND GLOSSOPTERIS IN SOUTH AFRICA. 330

Potonié mentions Sigillaria Brardi as a typical species in the
Ottweiler Beds and in the Upper Coal Measures and Permian rocks
generally.! This species is recorded by Zeiller from the Upper
Coal-Measure and Permian beds of Brive,” as well as from the Coal
Basin of Valenciennes,’ also from the Permian rocks of Bohemia‘ and
the Permian of Autun.’ The same form occurs moreover in beds
referred to a Permian age in Pennsylvania. Without multiplying
references to this species, enough has been said to show that it points
to a high horizon in the Coal Measures, or to a Permian age; as
Goppert says in his ‘ Permian Flora,’ the species is not uncommon in
Permian rocks.

' There is also some evidence, but not of the best, of another
species of Sigillaria, S. oculina, occurring in the Bunter Sandstone
of Germany. Blanckenhorn’ figured a specimen from this horizon
in 1886, and Weiss° subsequently confirmed his determination.
The preservation is by no means good, and an examination of
a cast of the specimen in the Bergakademie Museum, Berlin, did
not thoroughly convince me as to the Sigillarian nature of the
fossil. Blanckenhorn’s determination has, however, been accepted
by Sterzel,? Potonié,”® and other authors in addition to Weiss.

The occurrence of Sigillaria Brardi at Vereeniging is decidedly
in favour of the view already expressed, that these beds should be
referred to a Permo-Carboniferous age.

The most interesting feature in connexion with the occurrence
of Sigillaria’in South Africa in association with Glossopteris and
Gangamopt-ris is the coexistence of members of the Glossopteris-
flora and a typical representative of the Northern Hemisphere
vegetation of Permo-Carboniferous times. In 1895 Zeiller recorded
a similar association of Gangamopteris, Lepidodendron, and Lepido-
phlowos in the coal-beds of Rio Grande do Sul in Brazil.”

In a paper contributed by Dr. Blanford** to a recent number of
the Records of the Geological Survey of India, it is stated that
Dr. Kurtz has found a Lepidodendron in Argentina associated with
the Glossopteris-flora.. It is only lately that we have had satisfactory

1 «Die floristische Gliederung des deutschen Carbon u. Perm,’ Abh. k. Preuss
geol. Landesanst. n. s. pt. xxi. (1896) p. 14.

2 * Bass. houill. & Perm. Brive’ (1892).

3 ‘Bass. houill. Valenciennes’ (1886).

4 «Geologie von Bohmen,’ Katzer, pp. 1172, 1208 (Prag, 1892).

> Renault, B., ‘Bass. Houill. & Perm. d’'Autun et d’Epinac,’ fase. iv. p. 192
(1896).

6 Fontaine & White, ‘ Permian or Upper Carb. Flora,’ Second Geol. Surv.
Pennsylvania,’ PP. 1880.

7 Paleontographica, vol. xxxii. pl. xx. fig. 9, p. 132.

8 «Ueber eine Buntsandstein-Sigi/laria’ ... Jahrb. k. Preuss. geo]. Landesanst.
(1885) p. 356. :

® «Die Flora des Rothliegenden im Plauen’schen Grunde bei Dresden,’ Abh. k.
Sachs. Gesellsch. Wiss. vol. xix. (1893) p. 153.

10 Abh. k. Preuss. geol. Landesanst. n. s. pt. xxi. (1896) p. 41.

1) * Note sur Ja Flore fossile des Gisements houillers de Rio Grande do Sul,
Bull. Soc. géol. France, ser. 3. vol. xxiii. (1895) p. 601.

12 Rec. Geol. Surv. India, vol. xxix. pt. ii. (1896) p. 58.

336 MR. A, C. SEWARD ON THE ASsocraTion oF © [Aug. 1897,

evidence of the occurrence of the Glussopteris-flora in South America,
but the work of Kurtz and Zeiller, following the earlier account of
Brazilian plants by Carruthers,’ has yielded most important results.

Stated briefly, the questions suggested by these recent discoveries
of Lepidodendroid and Sigillarian plants associated with the
Glossopteris-flora of South America and Africa are these :—(i) Was
there a land-connexion between the continent of Gondwanaland
and the Northern Hemisphere continental areas towards the close
of the Paleozoic epoch? (11) May we regard the Lepidodendroid and
Sigillarian species of South America and South Africa as survivals
from an older period which preceded the typical Glossopteris-flora ?

The Glossopteris-flora is best known from the Indian rocks, and
in that region no specimens of Calamites, Sigillaria, or Lepidoden-
dron have so far been discovered. As Zeiller maintains, the Indian
genus Trizygia” of Royle is no doubt a Sphenophyllum, and there
are other connecting-links between the older Glossopteris-flora of
India and the Permo-Carboniferous vegetation of the Northern
Hemisphere. :

From the Malay Archipelago we have only the most meagre
evidence as to the occurrence at Sarawak of one or two members of
the Glossopteris-flora, and there is as yet no satisfactory evidence
of the existence of this flora in New Zealand. In Australia the
Glossopteris-flora is abundantly represented, but no instance has
been recorded of the association of a Lepidodendron or Sigillaria
with Glossopteris, Gangamopteris, or other characteristic member of
the Glossopteris-flora.

Several authors have made us familiar with the existence of two
great botanical provinces in Permian times, and probably during
the later phases of the Carboniferous period, but the facts on which
this view is founded need not be dealt with here.* There is not
wanting evidence in favour of the Glossopteris-flora having been
first differentiated in an Antarctic continent towards the close of
the Carboniferous epoch. It has left abundant traces of existence
in the now scattered regions which originally formed part of a large
continent to which the name Gondwanaland has been applied by
Suss and other writers. In connexion with this southern flora,
it is a matter of considerable interest to consider the possible
significance of the widespread boulder-beds of India, Australia,
Africa, and South America; but this question has been elsewhere
discussed by several writers, especially by Dr. Blanford, who has
thrown out many valuable suggestions bearing on the general
problem of plant-distribution. It is of interest to note a reference
in one of Darwin’s letters to the possibility of an Antarctic

1 Geol. Mag. 1869, p. 151.

2 «Sur la Valeur du Genre Zrizygia, Bull. Soc. géol. France, ser. 3, vol. xix.
(1891) p. 673.

3 See Blanford, W. T., Brit. Assoc. Rep. (Montreal) 1884, Pres. Addr. to
sect. C, p. 691 ; Quart. oun! Geol. Soc. vol. xlv..(1889) Proc. p. 95; ‘ Nature,’
vol. lii. (1895) p. 595; Seward, A. C. ‘Science Progress,’ 1807, p. lies also
an excellent article by Zeiller, on ‘Les Provinces bolas ue la Fin des
Temps primaires,’ Rev. gén. Sciences, Jan. 1897.

Vol. 53.] SIGILLARIA AND GLOSSOPTERIS IN SOUTH AFRICA. 337

continent. In writing to Hooker, he says:—‘I have sometimes
speculated whether there did not exist somewhere during long ages
an extremely isolated continent, perhaps near the South Pole.’ }

In rocks older than those containing Glossopteris or the associated
genera in Australia and South Africa, some plants have been de-
scribed by Feistmantel ? and others which prove the existence in the
Southern Hemisphere of Culm, Lower Carboniferous, and Devonian
species prior to the appearance of the Glossopteris-flora. In earlier
Carboniferous times some at least of the characteristic plants seem
to have had an almost world-wide distribution. May we recognize
in the Lepidodendra and Sigillarie of South Africa and South
America survivors of this older pre-Glossopteris vegetation? Or, on
the other hand, does the commingling of Northern and Southern
Hemisphere forms recently recorded point to local southerly ex-
tensions of certain members of the northern flora ?

It is difficult to give a decided answer to these questions. In
certain plant-beds of Culm age in Argentina there occur Lepido-
dendron and other genera which have been recorded also from beds
of the same age in Australia. In the latter country we have as
yet no evidence that these Culm types survived into the period of
the Glossopteris-flora, nor have we any evidence of the existence of
such types in India.

Bearing in mind the danger of relying too much on negative
evidence, we may, however, express the view that in Australia
the Lower Carboniferous and Devonian plants gave place in Permo-
Carboniferous times to a practically new set of forms, G'lossopteris,
Gangamopteris, and other genera. In India we know nothing as to
the vegetation of Lower Carboniferous times. In Africa and South
America there was not so complete a break between the Lower
Carboniferous and Permo-Carboniferous floras. We know that
typical Coal-Measure species existed in the Zambesi region in the
Upper Carboniferous period, and it would seem that the coal-beds of
Tete may be regarded as near to the most southerly extension of the
northern Coal-Measure vegetation. In the rocks of Vereeniging,
probably somewhat younger than those of Tete,* we have evidence of
the continuous existence and probable southerly extension of at least
one typical Permo-Carboniferous plant of the Northern Hemisphere,
namely, Sigillaria Brardi. Similarly in South America there was
the same southerly extension of northern forms. On the whole, the
simpler explanation of the facts appears to be to conclude that in
South America and South Africa the Glossopteris-flora contained a
few southern offshoots of the widely-spread vegetation which covered
an enormous area in late Carboniferous and early Permian times.
As Blanford and Zeiller have suggested, the two botanical provinces

1 «Life and Letters of Charles Darwin,’ vol. iii. p. 248 (London, 1887). Iam
indebted to Mr. Thiselton-Dyer for calling my attention to this remark.

? Mem. Geol. Surv. N.S. Wales, Paleontology, No. 3, 1890. See also
Szajnocha, L., ‘Ueber einige Carbone Pflanzenreste aus der Argentinischen
Republik,’ Sitzb. k. Akad. Wiss. Wien, vol. c. pt. i. (1891) p. 2038.

* Zeiller, Ann. Mines, Mém. ser. 8, vol. iv. (1883) p. 594.

Ond,G..8.. No. 211. ox

338 MR, A. C. SEWARD ON THE ASSOCIATION OF [ Aug. 1897,

overlapped in South America, and the same may now be asserted as
regards a certain area of South Africa.

There can be no doubt that the whole problem connected with
the geography and plant-distribution in the Southern Hemisphere at
the close of the Paleozoic and at the beginning of the Mesozoic Era
is well worthy of careful consideration. Our knowledge of the
paleobotany of Gondwdnaland is still far too fragmentary and
imperfect to admit of very definite and far-reaching conclusions, but
such data as we already possess are in need of a thorough and
comparative study. A superficial acquaintance with the scattered
literature of Southern Hemisphere fossil botany suffices to show
the need of a general survey of the plant records undertaken from
a botanical point of view, in order to afford the geologist a more
trustworthy contribution which may aid towards the solution of
important geological and botanical questions.

EXPLANATION OF PLATES.

(The photographs from which the figures have been reproduced were taken
by Mr. Edwin Wilson, Cambridge. The figures are slightly less than natural
size, except where otherwise stated.)

All the specimens, with the exception of that figured in Pl. XXTIL. fig. 1,
are in the British Museum (Natural History).

Puatse XXI,

Fig. L pide Browniana, Brongn., p. 320.
3 var. indica, p- 320.
3 ” 19 ” ” p- 321.
4a. var. angustifoia p. 821.
4b. N wggerathiopsis Hislopi (Bunb.), p. 322.
5. Leaf of doubtful affinity, p. 333.
6. Fragments of Glossopteris-leaves, g, g’, and one of ? Neggerathiopsis, a,
oe 399.

Puate XXII.

Fig. 1. Gangamopteris cyclopteroides, Feistm., p. 328.
2. Conites sp., p. 331.
3. Sigillaria ct. 8S. Brardi, Brongn., p. 326.
4a, ? Sigillaria sp., p. 330.
4b, Equisetaceous stem, p. 525.

Rather less than 3 nat. size.
4¢. Glossopteris Browniana, Brongn., p. 331. j

Puate XXIII.

Fig. 1. Glossopteris Browniana, Brongn., New South Wales, p. 318.
2. Sigillaria Brardi, Brongn, Pp. 326.

Puate XXIV.

Fig. 1. Phyllotheca sp., p. 324.
2. Calamitean (?) stem, p. 326.
3. ? Sigillaria sp., p. 880.

Vol. 53.] SIGILLARIA AND GLOSSOPTERIS IN SOUTH AFRICA. 339

Discussion (ON THE TWO PRECEDING PAPERS).

Dr. Buanrorp said that it was a source of much gratification to
those who, despite the views of many European paleontologists,
had maintained for many years on geological evidence that the
Glossopteris-fauna was Paleozoic, to find their contention confirmed
by recent botanical discoveries.

Mr. GrizsBacu pointed out that the fossil plants exhibited on the
table, showing true Carboniferous types associated with Gossopteris,
constituted another and valuable contribution to our knowledge of
these beds, which we know as Gondwanas in India; and they con-
firmed in a striking manner the fact, already accepted in India and
Australia, that the lowest beds of this group of strata belong to the
later Carboniferous and Permian systems. With regard to the
diagrams shown on the wall, he wished to point out that they were
not in strict accordance with the features as actually seen on the spot.
Neither does it appear probable that the various areas of coal-
bearing beds—as, for instance, Newcastle in Natal, Vereeniging,
Boksburg and Middelburg in the Transvaal—have been laid down in
one continuous basin as shown in the diagrammatic map exhibited.
These deposits show evidence, as do our Indian coal-basins, of
having been laid down in separate basins, probably marking systems
of rivers, in Permo-Carboniferous and later times.

Prof. Sretry stated that when he visited Aliwal North in 1889
Mr. Alfred Brown showed him many plants which he had obtained
in white sandstone. They included Glossopteris and Lepidodendroid
plants, together with a variety of ferns, which might be new.
There was no opportunity of visiting the locality; but Aliwal
North is near the top of the Karoo Series, and he thought
that Mr. Brown’s plants might be from beds yielding Huskele-
saurus, which he would place above the Indwe coal. There
are indications of coal near the base of the Karoo and in the
middle, but the workable beds which he had seen were towards
the top: although their flora was not the same as in the beds
worked by Mr. Brown, which resembled the types now exhibited.
He should like to see better evidence of the age of the beds before
admitting them as Permo-Carboniferous, because the whole of the
South African vertebrata of the Karoo appear to be below the beds
which are found near Aliwal North. The Lower Karoo comprised
the zone of Pareasaurus; then came the zone of Decynodon ;
above that is the zone of Ptychognathus; and at the top is the
zone of the Theriodont reptiles, which he placed below the Cape
coal. He had regarded all these beds as Permian.

Mr. Sronrer observed that in New South Wales Glossopteris
is characteristic of the more important of the productive Coal-
Measures. While on the Geological Survey staff, he spent two
years with Prof. David in the Farley and West Maitland districts,
where strata with workable coal-seams are sandwiched between
marine beds considered by De Koninck and others to be of Car-
boniferous or Permo-Carboniferous age. Not only is the section

24 2

340 SIGILLARIA AND GLOSSOPTERIS IN SOUTH AFRICA. [ Aug. 1897,

particularly clear, but the speaker had found Glossopteris in the
Marine Series, thus placing the matter beyond all doubt.

_ Feistmantel has described the Paleozoic plants; but there is a
difficulty, as stated by Mr. Seward, in distinguishing forms; and in
1894 Mr. R. Etheridge, Jun., pointed out that the whole question
of generic name, specific characters, etc. of Glossopteris had become
almost hopelessly involved. Gangamopteris and Gilossopteris are
associated at Lochinvar and Newcastle (N.S.W.).

Mr. Marr, in the absence of the Authors, pointed out that
Mr. Seward’s paper, which had been read in very brief abstract,
was mainly paleobotanical, and that the evidence brought forward
by Dr. Blanford, Dr. Waagen, and others as to the age of the beds
was relied upon by Mr. Seward.

Quart. JouRN. GEOL. Soc., VoL. LIII.. PL. XXI.

BEMROSE & SONS, LTD., COLLO,

GLOSSOPTERIS, NCGGERATHIOPS!Is.

Quart. JouRN. GEOL. Soc., VoL. LIII., PL. XXII.

leg
Fated

BEMROSE & SONS, LTD., COLLO.

SIGILLARIA.

GANGAMOPTERIS.

9 EQUISETACEOUS STEM.

"o

Quart. JourRN. GEOL. Soc., VoL. LIII., PL. XXIII.

BEMROSE & SONS, LTD., COLLO.

SIGILLARIA. GLOSSOPTERIS.

QuArT. JOURN. GEOL. Soc., VoL. LIII., PL. XXIV.

COLLO.

LTD.,

BEMROSE & SONS,

P SIGILLARIA.

PHYLLOTHECA.

Vol. 53.] | GLACIO-MARINE DRIFT OF THE VALE OF CLWYD. 341

25. The Guacto-Mariye Drrrr of the Vate of Cuwyp. By T.
Mettarp Reape, Esq., C.E., F.G.S., F.R.1I.B.A. (Read
April 7th, 1897.)

[Prats XXV—Map. |

In a paper on the Drift Deposits of Colwyn Bay, I pointed out
that the bulk of the materials of the sands and clays forming the
Colwyn drift had been derived from the Vale of Clwyd. In
January, 1896, I had the opportunity of tracing the deposits farther
westward past Llandulas and into the Vale itself. These later
observations quite bear out my original statement.

(1) Boulder Clay from Craig, west of Llandulas, to the
Vale of Clwyd, south-east of Abergele.

Immediately east of Craig, between Llandulas and Colwyn Bay
(No. 1 in the Map) the Boulder Clay stands out in vertical cliffs
about 30 feet high, and so compact that it is undercut by the
waves, in a manner similar to that often seen in rock-cliffs. <A
closer examination shows that it is very full of angular fragments of
limestone, derived from the Carboniferous Limestone-rock against
which it les. Several large blocks of Welsh felstone and blocks of
slate-rock—showing banding or original bedding—occur on the
shore, and I found a small boulder of Eskdale granite in the clay.
At one place the clay appears to be foliated in a vertical direction.
It does not appear that there are many shell-fragments in the clay,
as I found only one example. All the Boulder Clay described in
this paper is of a brown or reddish-brown colour, containing
northern erratics, and is similar to the low-level Boulder Clays of
Lancashire and Cheshire, excepting where it is mixed with the
waste of the hills against which it may happen to lie.

A microscopic examination of a specimen of the clay by Mr.
Joseph Wright, F.G.S., for foraminifera yielded negative results.

The following is a mechanical analysis showing the constitution
of the clay ; specimen taken about 5 feet above the shore :—

Weight before washing = 1:000 = 5oz,

Caught: in j,-inel: mesh, ., ....20.cscscsesense0e 0-191
” ao 99 Cte e rec vcccccccscncces 0:033

” tae G90) eee wlacecicltncnilcsineviescies 0:075
Passed do. & deposited by subsidence ...... 0-208
0°507

This leaves 50 per cent. of clay, if we count as clay all the material
washed out in the operations.

+ Quart. Journ. Geol. Soe. vol. xli. (1885) pp. 102-107.

342 MR. T. MELLARD READE ON THE [Aug. 1897,

Immediately west of the West pier at Llandulas, there is a spur
of extremely fine Boulder Clay standing out from the cliff; out of
this I took one granite-pebble. Notwithstanding its freedom from
stones, the clay is extremely hard where unweathered.

Mechanically analysed, the specimens taken (No. 2- in the Map)
yielded 80 per cent. of clay. Between 4 and 5 lbs. troy of the
Boulder Clay yielded to Mr. Wright the following foraminifera’:—

Miliolina seminulum (Linn.). Very rare.
oe subrotunda (Mont.). Rare.
Bolivina dilatata, Rss. Rare.

», plicata, Orb. Common.
Cassidulina crassa, Orb. Common.
Lagena suleata (W. & J.). Very rare.

» hexagona (Will.), var. Very rare.

» levigata (Rss.). Rare.

Uvigerina angulosa, Will. Rare.
Globigerina bulloides, Orb. Common.
Patellina corrugata, Will. Very rare.
Discorbina rosacea (d’Orb.). Rare.

a Bertheloti (V’Orb.). Very rare.

- Wrightti, Brady. Rare.
Truncatulina lobatula (W. & J.). Rare.
Nonionina depressula (W. & J.). Very common.
Polystomella striato-punctata (KF. & M.). Rare.
macella (KF. & M.). Rare.

lojelol elgiglolleloic
4 4444445235

ololo
a4

99

One hundred specimens of Nonionina depressula were obtained
from this gathering, while the other 17 species numbered in all
only 69 specimens.

Farther east, between the East and West piers, the cliffs of drift
are well developed. A very shelly clay occurs here, and I picked
out Turritella teredbra, Trophon truncatus, Cardiwm edule, ete. The
lower part of the cliff is grass-grown, but in a good exposure about
30 feet above the shore I took a specimen of the clay (No. 3 in the
Map). Mechanically analysed, it yielded 35 per cent. of clay,
showing, curiously enough, a smaller proportion of that material
than the strong clay to the east of Craig already described, but this
arises from the preponderance of sand-grains having a diameter
between 51, and =, inch, together with the flour of rock deposited
in the washing. ‘This specimen is interesting from the numerous
foraminifera it contained. Mr. Wright examined 1 lb. 1 oz. troy,
and found the following species :—

' For purposes of comparison I have marked those species that occur in the
Boulder Clay of Great Crosby with a C (see ‘Foraminiferal Boulder Clay at Great
Crosby,’ Proce. Liverp. Geol. Soc., Session 1895-96, vol. vii. pt. iv. pp. 888-390),
and those that occur in the Boulder Olay of Wirral, Cheshire, with a W (see
paper by Davies & Reade, Proc. Liverp. Geol. Soc., Session 1894-95, vol. vii.
pt. ili. pp. 834-3835 & pp. 342-344),

Vol. 53.] | GLACIO-MARINE DRIFT OF THE VALE OF CLWYD. 343

W. Miliolina seminulum (Linn.). Very rare.

W. ie subrotunda (Mont.). Frequent.
C. = tenwis (Cz.). Common.

Ammodiscus gordialis (J. & P.). Very rare.

C.W. Bulimina pupoides, @Orb. Rare.
C.W. ” Susiformis, Will. Very rare.
C.W. Bolivina dilatata, Rss. Frequent.
C.W. ce plicata, VOrb. Very common.
C. Cassidulina levigata, VOrb. Very rare.
C.W. i crassa, V Orb. Very common.
O.W. Lagena sulcata(W. & J.). Very rare.
C.W. » Williamsoni (Alcock). Rare.
C.W. » lineata (Will.) var. Very rare.
C.W. » hexagona (Will.) var. Very rare.
C.W. » sguamosa (Mont.). Very rare.
C.W. » Orbignyana (Seg.). Very rare.
GW. levigata (Rss.). Rare.

Rhabdogonium tricarinatum, VOrb. Rare.
Polymorphina lactea (W. & J.). Very rare.
- myristiformis, Will. Very rare.
C.W. Uvigerina angulosa, Will. Frequent.
C.W. Globigerina bulloides, VOrb. Very common.
Spheroidina bulloides, d’Orb. Rare.
Pullenia spheroides (V’Orb.). Very rare.
Patellina corrugata, Will. Very rare.
Spirillina vivipara, Eliz. Very rare.
C.W. Truncatulina lobatula (W. & J.).. Common.
Pulvinulina Menardii (WOrb.). Rare.
C. és Karsteni (Rss.). Very rare.
C. Rotaha Beccarti (Linn.). Very rare.
C. Discorbina Wrightti, Brady. Common.
C.W. Nonionina depressula (W. & J.). Very common.
C.W. Polystomella striato-punctata (F. & M.). Frequent.
- macella* (F.& M.). Very rare.

About 650 specimens of Nonionina depressula were obtained
from this gathering, while the other species numbered in all 235
specimens,

Mr. Wright observes that some of the forms from this sample are
extremely rare as British specimens. Rhabdogonium tricarinatum
and Spheroidina bulloides have been met with at a few places only
off the west coast of Ireland ; Pullenia spheroides has been recorded
only from off Dublin and the estuary of the Dee, and Pulvinulina
Menardit from the Isle of Man and from off the coast of Dublin.

These drift-cliffs continue at a lower elevation to the River
Dulas, at the mouth of which is a pebble-ridge, forcing it to the
eastward. The valley of the Dulas has been drift-filled and since
then denuded, the gravels in it being of later date.

Beyond the Dulas to the east is a low bank of drift grassed over.
The same kind of Boulder Clay as that hitherto described may be
seen in a section at the large limestone-quarries at Llandulas, at a
level of 150 feet above O.D., lying upon the irregular surface of
the Carboniferous Limestone.

' In the Brit. Assoc. Report on the ‘High-level Shell-bearing Deposits of
Kintyre,’ (L’pool) 1896, p. 397, Dr. David Robertson states that, so far as

he knows, Polystomella macella has not been found in recent deposits in the
British Isles, and in Scotland it is only found in the shelly deposits of Kintyre.

344 | MR. T. MELLARD READE ON THE [ Aug. 1897,

A walk of about a mile along the St. Asaph road from Abergele
shows drift banked up against the limestone-cliff on the west side of
the Vale of Clwyd: it is conterminous with that of the shore-cliffs
just described.

Kast of the St. Asaph road, and at a level of about 140 feet above
O.D., is a disused brick-pit, showing a plastic red Boulder Clay, very
like that in the cutting of the Wirral Railway at Seacombe.’ In
it are a good many shell-fragments, mostly very rotten, among
which Cardium, Turritella, and Tellina are distinguishable,

A mechanical analysis of this clay (No. 4 in the Map) showed
that the matter separated by the sieves was mostly sand, the larger
part of which passed the ;},-inch mesh. The sand consists to a
great extent of most beautifully rounded and polished quartz-
grains. The proportion of clay was very high, amounting to 82
per cent.

Three lbs. of this clay were submitted to Mr. Wright, in which
he discovered the following species of foraminifera :—

Bulimina pupoides, V’Orb. Rare.
marginata, d’Orb. Very rare.
Bolivina dilatata, Rss. Rare.

9 plucata, Orb. F requent.
Lagena lineata (Will.). Very rare.

» hexagona (Will.). Very rare.
Nodosaria (D.) communis, @Orb. Very rare.
Globigerina bulloides, @Orb. Frequent.
Discorbina rosacea (d’Orb.). Very rare.

re Wright, Brady. Rare.
Truncatulina lobatula (W.& J.). Rare.
Nonionina depressula (W. & J.). Very common.
Polystomella striato-punctata (F.& M.). Rare.

220080 eacaaa
445 33 4532245

Ninety specimens of Monionina depressula were obtained from
this gathering, while the other 13 species numbered in all only
34 specimens.

On the east side of the St. Asaph road, a short distance up the
road, immediately N.W. of Parc-y-Meirch, is a limestone-quarry
about 280 feet above O.D., and it is seen here that the drift runs
up and chokes the valley. It is full of Wenlock Shale, mixed with
limestone and much rounded shingle. Following the valley upwards,
it is evident that the whole is drift-filled, and not only so, but the
drift sweeps over the hills, giving them their rounded outlines.
Pare-y-Meirch is an old entrenched camp on a drift-covered hill. At
a level of about 555 feet above O.D. I found a large boulder of
nodular volcanic ash, which looked to me very like Arenig. I
submitted the specimen to Mr. Thomas Ruddy, of Palé, who is very
familiar with the volcanic rocks in this part of North Wales, and he
says that he considers it to be the nodular ash described by Ramsay
at p. 93 in vol. iii. Mem. Geol. Surv. He has found boulders of it
near the village of Cerrig-y-Druidion. At the road crossing the

1 Davies & Reade, Proc. Liverp. Geol. Soc., Session 1894-95, vol. vii. pt. iii.

Vol. 53.]| | GLACIO-MARINE DRIFT OF THE VALE OF CLWYD. 345

St. Asaph road, north-west of Parc-y-Meirch, 220 feet above O.D., a
stream has cut into the drift, over which it falls for a few feet as
a waterfall, and here is disclosed a well-stratified sandy deposit.

My observations generally go to show that the drift here described
represents a shore sloping up gradually from the lowland of the Vaie
of Clwyd, until it is backed up at a greater angle against the lime-
stone-cliffs forming the west side of the Vale.

(2) Glacial Sands and Gravels, east side of the
Vale of Clwyd.

The country between Rhyddlan and Diserth is mostly covered
with red sand, evidently derived from the Trias, which is the bottom —
rock of the Vale.*

South-east of Diserth Castle, near Prestatyn Branch Railway, is a
striking grass-covered mound of sand and gravel (No. 5 in the Map),”

Esker south-east of Diserth Castle.

7 CATS ee ed
a SP
SS nears,
Se Se eee ae
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Large Limest

one - Boulders
the structure of which may be investigated where it is broken into .
by the excavations for gravel. The axis of this mound has a
north-easterly trend, and it forms a spur from the hill on which it
lies. Orographically it resembles an Irish esker. The excavation
shows that the bedding of the sand and gravel largely follows the
external form, the flank, where exposed, being covered with a
layer of Boulder Clay, as illustrated in the above diagram. In the

1 Between “Abergele and Rhyddlan the Glacial beds are masked by post-
Glacial deposits, but borings seem to show that Boulder Clay and Sands alternate.
There are good sections of the Marine Drift on the river-bank at Rhyddlan, and
these have been described by Prof. M°K. Hughes, ‘ Geol. of the Vale of Clwyd,’
Proc. Chester Soc. Nat. Sci. 1884, no. 3. See also remarks on Drift in ‘ Trias of
the Vale of Clwyd,’ Proc. Liverp. Geol. Soc., Session 1890-91, vol. vi. pt. iii. p. 285.

* See ‘Geology of Rhyl, Abergele, and Colwyn’ (p. 32 & map), by Aubrey
Strahan, Mem. Geol. Surv.

346 MR, T. MELLARD READE ON THE [Aug. 1897,

gravelly sand that runs loosely down the flanks of the excavated
portion were marine shell-fragments of the usual type.

The pebbles are preponderatingly of Carboniferous Limestone.
There are too a great many boulders of the same rock lying about
that have been taken out of the mound. Boulders and pebbles of a
fine-grained felstone also abound, and these may have come from
the Snowdon range. There are, moreover, other rocks which both
Mr. Ruddy and I consider to be from the Arenig.

At A (see diagram, p. 345) I took a specimen of the sand and
gravel, at a level of about 350 feet above O.D. The result of
mechanical analysis was as follows:—

Weight before washing = 5o0z. = 1:000.

Caught in 45-inch mesh ......... 0-700

a ty Sa Vel leweasces 0-083

& rio Bled (Depa Site 0-100

Passed j4ih5 ike. de Soceeeeees 0:050

Clay? = 7 per cent. 0:933

The ;-inch material contained some extremely rounded and
beautifully polished pebbles, measuring from 3 inch on the longer
axis down to ¢ inch, of very hard, green, igneous rock ; there were
also pebbles of limestone, sandstone, vein-quartz, and a few shell-
fragments. None of this matérial was striated, but it had a beach-
worn appearance.

The material from the smaller meshes consisted, as is generally
the case, of a larger proportion of quartz-grains as the material
became smaller. Many of them were rounded and polished, but
mixed with irregular quartz-splinters. The material is largely
calcareous, as shown by its bubbling up strongly on the application
of acid.

The Boulder Clay on the flanks of the mound, although it was
seen on the ground to contain small shell-fragments, did not yield
foraminifera to Mr. Wright, who examined a specimen from B (see
diagram, p. 345). The stones, he reports, were more or less rounded.

The Boulder Clay appears to cover the surrounding country,
being seen in the cutting of the Prestatyn Branch Railway, ac-
cording to Mr. Strahan, so that the gravel-mound must rise up
through it. On the road to Newmarket, at a level of about 500 feet,
a sand-pit (No. 6 in the Map) shows yellow stratified sand, with
frequent shell-fragments.

These flanking deposits on either side of the Vale of Clwyd
bear all the appearance of marine clays and sands, and are, as I
have shown in detail, full of the remains of marine organisms.
Similar deposits, in this case consisting mainly of the red sand
of the Vale of Clwyd, can be traced up the River Wheeler into
the valley of the Alyn and down to its junction with the Dee.
Farther up the Vale of Clwyd this marine drift gives place to a
more local drift, which has come, as shown by Mr. Strahan, from

Vol. 53.] | GLACIO-MARINE DRIFT OF THE VALE OF CLWYD. 347

the south-west. We have also seen that the Arenig rocks are to
be found at various localities, even among the marine deposits of
the mouth of the Vale.

It is not my object here to attempt to explain these phenomena,
but to place on reccrd the results of a more minute examination of
the nature of the clays and sands found at the entrance of the Vale
of Clwyd than appears to have been hitherto made. It is interesting,
however, to observe from the lists and localities given that the
Marine Boulder Clays of Lancashire, Cheshire, and Denbighshire
contain more frequently, and in a much greater profusion than was
suspected, the tests of foraminifera. As a rule, these are found in
the finer and more plastic brown or red Boulder Clays, which often
contain intensely-striated erratic stones, and they occur in just the
sort of deposits in which they are mostly found at the present day.
It is certainly remarkable that they are so well preserved, when
frequently large boulders of dolerite and other originally hard rocks
have crumbled to sand in the same beds.

PLATE XXV.

Geological Map of part of the Vale of Clwyd on the
~ scale of 2 miles to the inch.

DiscussIon.

Mr. Srrawan drew the attention of the Author to Prof. Hughes’s
exhaustive papers on the drifts of the Vale of Clwyd. The
occurrence of foraminifera was to be expected in clay so similar to
that of Cheshire, in which they had long since been recorded by
Mr. Shone. One of the most interesting points in the drifts of the
Vale was the meeting of drift from the north with the local drift
of North Wales. He congratulated the Author on the result of his
careful examination of the clay.

Prof. Hueuns said that he had laid pretty fully before the Society
his views as to the origin and classification of the drifts of the Vale
of Clwyd (Quart. Journ. Geol. Soc. vol. xliii. 1887, p. 73); and he
gathered from the too short exposition of Mr. Mellard Reade’s recent
observations in that area, that the foraminifera which he had obtained
all occurred in the newer or St. Asaph Drift. This had all the
characteristics of the shore-deposits on that coast at the present day.
It contained boulders washed out of pre-existing Boulder Clays,
thus commingling the products of the land-ice from the Welsh
mountains with the northern boulders rolled in the shore-deposits.
There were lumps of the older clay which had been trundled along
the shore, so that the outside was covered with gravel, sand, and
shells which had stuck to it. There were fragments and rarely
whole specimens of shells thrown up from various habitats, just as
they occur in the shore-shingle at the present day; and in some of
the gasteropods foraminifera were found washed up from sea-
bottoms of various character and depth, as at the present time.

348 GLACIO-MARINE DRIFT OF THE VALE OF cLwypD. [Aug. 1897,

The shells in the St. Asaph Drift were, with few exceptions, of the
same species as those which now occur on that coast, and the
exceptions were Scandinavian, not Arctic.

Mr. P. F. Kenpatt also spoke.

The AvrHor, in reply to Mr. Strahan, said that tr Shone
obtained his foraminifera from the material in the interior of
Turritelle, and not from the clay-matrix in which they were
embedded. The late Dr. Robertson examined Boulder Clay from
the Atlantic Docks, Liverpool, for the Author; and the list of
foraminifera is given in his paper on the ‘ Drift Beds of the
North-West of England,’ published in the Society’s Journal. It
was not, however, until the Boulder Clays in the Wirral Railway-
cutting, Cheshire, were examined by Mr. Wright and found to be
rich in foraminifera, that the Author realized the importance of the
subject. Since then many samples of clays from Great Crosby,
Lancashire, Blackpool, the Vale of Clwyd, and Ayrshire have been
examined by Mr. Wright with the same result. The organisms
occur most plentifully in the finer clays and are well preserved, the
facies being very similar from all the localities in England, Wales,
and Scotland—jointly pointing to the conclusion that they are not
derived fossils, but have lived and died where they are found. The
Boulder Clay of the Vale of Clwyd here described is identical with
the Low-level Marine Boulder Clay of Lancashire and Cheshire.

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Geol. Soc. Vol, LITI. Pl. XXV.

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Scale of 0
Che black spots indicate

APER
RIFT OF THE
iferous Limestone

Quart. Journ. Geol. Soc. Vol, LIT. Pl. XXV.

MAP TO ILLUSTRATE
Mr. MELLARD READE’S PAPER

ON THE GLACIO

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nr Viel 5 3. ORIGIN OF SOME OF THE GNEISSES OF ANGLESEY. 349

26. On the Ortein of some of the Gunisses of AwnetmsEY. By
Cuartes Cattaway, M.A., D.Sc., F.G.8. (Read April 28th,

1897.)
ConTENTS.
Page
Rear OM IG OMIM: Seti ns wee Se us Wee cae odes cod saaan eee oceans 349
I. The Materials out of which the Gneisses are formed ...... 350
The Granite. The Felsite. The Diorite.
If. The Products of the Metamorphism ...............0..+:20e+++ 351
A. Simple Schists. Mica-gneiss from Granite. Horn-
blendic and Chloritic Gneisses from Diorite. Mica-
GNIS FE OMI HEISILG fee oma. canines ded sactelenis on stabs oals osha 351
IBS injechiom-mcliststs, sacvarcacestssasnendetcn adds noanssusscpasnce 353

(1) Gneiss of Primary Injection. Various Sections.
Diorite-blocks in the Grey Gneiss.
(2) Gneiss of Secondary Injection.

INTRODUCTION.

THE comparative ages cf the subdivisions of the schistose and
gneissic rocks of Anglesey have been discussed with very varied
conclusions, but these discrepancies have been in great part the
result of the unsettled state of opinion on the subject of meta-
morphism. ‘The former belief that the granite was of metamorphic
origin, and that a parallel structure necessarily indicated an original
sedimentation, could not fail to mislead the stratigraphical geologist.
It is therefore requisite that the genesis of the respective rocks
should be determined before attempting to revise the old classifications.

Before entering upon my task, I wish to indicate briefly the
present state of our knowledge of the Archean (pre-Cambrian)
rocks of Anglesey. Dr. H. Hicks, F.R.S., divided them into three
groups :—Dimetian (granite), Arvonian (hilleflinta), and Pebidian
(schistose), these divisions being named in ascending order.’ I have
never been able to define more than.two systems, an older one,
which, to avoid theory, I simply designated as ‘Gneissic,’ and a
newer one, which I described as ‘Slaty,’ and provisionally identified
with the Pebidian.2 The Rev. J. F. Blake, F.G.S., admits the
pre-Cambrian age of all these rocks, but he describes them as one
continuous series, which he calls ‘Monian.’’ Prof. T. G. Bonney,
F.R.S., also regards the crystalline schists as Archean,* but Sir A.
Geikie,’? F.R.S., and Prof. T. M°K. Hughes,’ F.R.S., place some
of the less altered schists at a higher horizon. The pre-Cambrian
age of the bulk of the granitic, gneissic, and schistose rocks of
Anglesey may therefore be regarded as a settled question; but

' Quart. Journ. Geol. Soc. vol. xxxv. (1879) p. 302.
2 Ibid. vol. xxxvii. (1881) p. 211.

3 Ibid. vol. xliv. (1888) p. 463.

4 Ibid. vol. xxxv. (1879) pp. 303, 304.

® Ibid. vol. xlvii. (1891) Proc. p. 180.

® Proc. Phil. Soc. Cambridge, vol. iii. (1880) p. 347.

350 DR. C. CALLAWAY ON THE ORIGIN OF [Aug. 1897,

whether they are to be referred to one, two, or three epochs remains
still in dispute.

My own views as to the broad outlines remain unchanged after
many years’ intermittent study of Anglesey geology. The newer
series I still regard as Pebidian, and I have nothing material to alter
in the details of the distribution of this group and the succession of
its members. The gneissic rocks belong, I have no doubt, to an older
epoch; but I now believe them to be an igneous complex, which
has undergone great chemical and structural changes under the
influence of pressure and heat. In these rocks I once described a
succession-in-time, which must of course be abandoned.

In this paper I shall not touch upon the Pebidian rocks, or
attempt an exhaustive study of the older masses ; but will confine
myself to a description of the production of the gneissic structure
in some very interesting sections in the south of the island. This
will, I hope, be of service in clearing the ground for further
research.

I. Tue MaTteERIALS OUT OF WHICH THE GNEISSES ARE FORMED.

These gneisses have been produced out of a granite, a felsite, and
a diorite, either separately or in combination.

The Granite-—This rock has been described by Prof. Bonney ’* as
consisting mainly of quartz and felspar. It is clearly of igneous
origin, for, on the shore near Porth Nobla, masses and veins of it
are seen to penetrate the adjacent rocks. It will be but slightly
noticed in this paper.

The Felsite—This is in part the Arvonian of Dr. Hicks. Great
difficulty has attended the study of this rock, owing to the enormous
mechanical pressures to which the igneous complex has been
subjected. Ordinarily it presents the appearance of the rock which
has been vaguely described as ‘ halleflinta.’ In hand-specimens it
is seen to be fine in grain and of uniform texture, more like a fel-
spathic mud than an eruptive rock. A specimen of it was described
by Prof. Bonney ? in 1881 as similar to the Treffgarn (St. David’s).
hilleflinta, but as ‘more gneissic’ under the microscope. At that
date he leaned to the opinion that the Anglesey hialleflinta ® is of
‘fragmental origin,’ but admitted that the structure sometimes comes
‘nearer to that of some microcrystalline felsites.’ | Mr. Blake
considers * the hialleflinta of Roche Castle (St. David’s) to be an
altered andesite, and probably few will now dispute that hiilleflinta
is often an eruptive. The subsequent study of a large number of
the Anglesey slides has convinced me that the fragmental structure
is merely hypoclastic, and is the result of crushing, being in fact an

1 Quart. Journ. Geol. Soe. vol. xxxv. (1879) pp. 307, 308, nos. vii, ix, & xi.

2 Tbid. vol. xxxvii. (1881) p. 238.

3 This rock must not be confounded with the quartz-felsites associated with
the granite, which are truly a part of the granitic intrusion, and often imper-
ceptibly grade into the granite.

4 Quart. Journ. Geol. Soc. vol. xl. (1884) p. 308.

Vol. 53.] SOME OF THE GNEISSES OF ANGLESEY. 351

early stage in the conversion of felsite into schist. Evidence of this
conclusion will be offered further on.

The Diorite.—This rock is now well known. Near Gaerwen it
is modified into hornblendic and chloritic gneiss, as I showed? in
1887. Mr. Blake? has confirmed and extended this result.

Il. Tur Propucts oF THE METAMORPHISM.

In a series of papers* on the Malvern crystallines, I have
expounded the changes which, in that area, take place in plutonic
rocks during dynamo-metamorphism. It was seen that schists
and gneisses are formed sometimes by pressure acting upon a
single rock, but the most important results were shown to be pro-
duced in diorite interlaced by granite-veins. Similar results have
been observed by me in Anglesey. JDiorite alone is converted into
various gneisses, felsite alone is changed to mica-gneiss; while
extremely interesting gneisses of another type are formed where
diorite is interveined with felsite.

The processes of metamorphism in Anglesey bear so close a
resemblance to those which have operated at Malvern that the
classification of gneisses and schists adopted in my researches in the
last-named area will be usually applicable in this paper.

A. Srmupzz Scuists, or those formed from one kind of rock.

Mica-qgneiss from Granite.—This change is sometimes seen near
the margin of the central granite-band, but it is of the ordinary
kind, and need not be described here.

Hornblendic and Chloritie Gneisses from Diorite.—These types
have been already noticed, and references to descriptions of their
origin have been given.

Mica-gneiss from Felsite——A. fine section showing this change is
exposed along the western end of a crag in a field at Y Graig, near
Gaerwen, at a little distance from the gate leading into it from the
road from Gaerwen. The rock is very sound and clean, and the trans-
ition can be traced inch by inch without any break caused by frac-
ture or turf-covering. At the northern end is felsite, which passes
gradatum through the intermediate form of halleflinta into a typical
mica-gneiss. At the British Association Meeting at Manchester in
1887, I exhibited a series of slides from this section. The first
(No. 379 *) of the set was admitted by Profs. Bonney and Renard,
and by Mr. J.J. H. Teall, to be a true felsite. Under the microscope,
it polarizes as an aggregate of granules of various sizes, with foliate
interlocking margins. Several crystals of felspar, some of them
plagioclase, are scattered through the groundmass. A few of
them have been broken, and the parts shifted, and the granular

1 Brit. Assoc. Rep. (Manchester) 1887, p. 706.

2 Ibid. (Bath) 1888, p. 405.

3 Quart. Journ. Geol. Soe. vol. xliii. (1887) p. 525; 2bid. vol. xlv. (1889) p. 475;

abid. vol. xlix. (1893) p. 398; Geol. Mag. 1892, p. 545; ibid. 1893, p. 535; ibid.
1894, p. 217; & zbid. 1895, p. 220.

4 The numbers in parentheses are those of the slides in my cabinet.

352 DR. C. CALLAWAY ON THE ORIGIN OF [Aug. 1897,

constituents have also been somewhat crushed. There is also present
a fair sprinkling of small highly-refracting crystals. Amongst them
are both epidote and sphene. A few small patches of quartz are
scattered through the slide. This felsite passes within an inch or
two into a rock which, megascopically, appears rather less compact,
and would be called a halleflinta. Microscopically (418), it does
not essentially differ from the last, but there is a slightly parallel
structure among the granules, and quartz has been developed in
a more streaky manner, the streaks running with the incipient
foliation. A very minute quantity of chlorite and white mica
accentuates the parallel arrangement, and streams of minute sphenes
run in the same direction. Another slide (380) at about the same
distance from the first shows a structure similar to that of no. 418;
but the parallel arrangement is rather more marked, and the
colourless mica is somewhat more abundant. The hand-specimen,
however, from which the slide is cut is a fairly typical hilleflinta,
the schistosity and the presence of mica being scarcely perceptible.
The streaks of quartz do not occur in this or any of the following
slides.

Seven more thin sections, taken at intervals of a few inches, show
the progressive change into a well-marked gneiss. In 381 the
mica is more abundant than in the last. Felspar can be identified
in distinct folia of idiomorphic crystals, both plagioclase and micro-
cline being present. No. 382 contains rather less mica. Nos. 383
and 384 are generally similar to the two preceding slides. A little
brown mica appears in 385, seemingly in distinct shear-planes, as if
it might have resulted from infiltration, the diorite in mass being at
no great distance. No. 386 is very gneissic, white mica being fairly
abundant, and several distinct folia of fresh-looking felspar being
present. The last slide (387) of the series is a beautifully foliated
gneiss. Micas, both white and brown, are plentiful, the latter, as
before, appearing in well-marked shear-planes. I do not mean to
suggest that the white mica also is not generated at shear-planes;
but with the brown mica the planes are very conspicuous, being
indicated, where the biotite thins out, by brown iron-oxide. The
folia intervening between the mica-seams display mosaic polarization,
and very little felspar can be indentified. Strain-shadows are well-
marked in this slide. A few small garnets are present.

I have traced similar gradations in rocks at Holland Arms, on the
Menai Straits, and elsewhere. It is easy to obtain hand-specimens
which show hilleflinta in one part and mica-gneiss in another, with
gradations between. I have examined a large number of micro-
scopic slides of these specimens. The part which would be described
as hilleflinta usually shows signs of great crushing, and the specimen
(379) from Y Graig still remains the only example which can be
positively identified as felsite.

We are not, however, left to the unsupported testimony of the
microscope, for, as we shall see in the next division of this paper,
the hialleflinta behaves hke a true eruptive, penetrating other rocks
in veins, and enclosing blocks of the adjacent masses.

Vol..53.] SOME OF THE GNEISSES OF ANGLESEY. 353

B. Inzection-ScHists.

In two of my Malvern papers I have described two kinds of
injection-schist, those produced by the injection of rock (primary
injection) and those formed by the infiltration of mineral matter
along shear-planes subsequent to consolidation (secondary injection).
Both of these varieties of schist! are to be seen in Anglesey.

In Anglesey the felsite plays the part which at Malvern is taken
by the granite, but certain important differences arise. The granite
of Malvern is very coarse in grain, and the shear-lenticles are
normally short, thick in the middle, and irregular, so that the
gneissic banding is also more or less irregular. The Anglesey
felsite, however, being fine-grained and compact, shears under
pressure into very regular lenticles. These are often very thin,
almost like sheets of paper. When the intervening shear-planes
are covered by infiltration-products and the lamine are puckered, a
very striking and beautiful effect is produced.

(1) Gneiss of Primary Injection.

This variety is formed by the parallel interveining of felsite and
diorite. According to the Rey. J. F. Blake,” the diorite is intrusive
in the gneissic rock, which, in my view, has been formed from the
felsite. My own impression is that the diorite is the older rock,
and that portions of it which look like dykes are really included
masses. The sections at Llangaffo and Y Graig, which I am abont
to describe, seem to support this opinion, but the point is not very
material.

Section in the Llangaffo Ratlway-cuiting.

In fig. 1 (p. 354) we see numerous * felsite-veins included in a
dark-green rock of somewhat gneissose structure, passing within a
few feet into foliated diorite, and even into a diorite which is
scarcely foliated at all. Mr. Blake truly affirms (loc. cit.) that this
dark rock agrees in all respects with the well-known diorite at
Gaerwen. The felsite-veins vary in thickness from several inches
or even feet to the tenuity of a wafer. Many of them are entirely
surrounded (in section) by the diorite. They lie in the direction of
the prevailing schistosity, and frequently run out into sharp points,
as if compressed.

Section at Y Graig, Gaerwen.

Further evidence of the eruptive origin of the grey gneiss is
seen in a small quarry on the east side of the road at Y Graig.
The vertical face exposed in the bank mainly consists of horn-
blendic gneiss (modified diorite) dipping at nearly 90°. Running

1 JT use the term ‘schist’ in preference to ‘gneiss,’ since felspar may be
sometimes absent in this type of rock.

2 Quart. Journ. Geol. Soc. vol. xliv. (1888) p. 504.

3 Only a small proportion of them are shown.

Q.J.G.8. No. 211. 2B

do4 DR. C. CALLAWAY ON THE ORIGIN OF [Aug. 1897,

parallel with the foliation are several veins of grey fine-grained
rock, some of which are a kind of halleflinta, while others are
foliated. They range in breadth from several inches to less than a
line. Some of the thicker veins show a gradation within an inch
or so between hilleflinta and gneiss. Similar veins appear in the
floor of the quarry, and strike across the road, sometimes branching.
They thin out to a point. Itis incredible that this grey rock should
be sedimentary, and it is almost equally difficult to believe that it
can be older than the diorite in which it is enclosed.

Fig. 1.—Gneiss of primary injection, Llangaffo.

YY
yy i,

Yj

YU

Uy Y
Wy fy

In thin sections some of the felsite (or hilleflinta) exhibits the
minutely-granulated structure of the grey veins at Llangaffo ; but
it contains numerous granules of epidote, the effect, perhaps, of
the chemical action of the enclosing diorite. Junction-specimens
show this felsite to be interlaminated with bright, clear horn-
blende (whether by veining or infiltration I cannot say), and
sometimes we observe the hornblende to alternate with fresh, clear
plagioclase in long prisms lying in different directions. It would
thus appear that in this locality there has been an actual fusion of
some of the constituents, resulting not only in the generation of
new minerals, but in the regeneration of the hornblende.

Turning into the field close at hand, we come to the typical
section (p. 356) of felsite graduating into grey gneiss, and we are
thus led to infer that the veins in the road proceed from the same
mass.

Section at Porth Gwyfen.

On the shore at this locality there is a very clear exposure of a
striped gneiss similar to the section shown in fig. 1. Grey gneiss
and dark-green schist run into each other in numerous thin bands.
The gneiss passes in places into halleflinta, and veins of the grey
rock, in the form of either halleflinta or gneiss, are also seen in the
green schist at a distance from the junction of the tworocks. In an
easterly direction the grey veins come in more and more abundantly,
till we reach a large mass of grey gneiss.

Wols53.] SOME OF THE GNEISSES OF ANGLESEY. 309

Diorrte-blocks in the Grey Gineiss.

The eruptive origin of the gneiss is also shown by another kind
of evidence. In the Llangaffo section a number of irregular blocks
are enclosed in the grey gneiss (fig. 2). They consist largely of

Fig. 2.—Blocks of altered and squeezed chorite in grey gneiss.

[At a and 6 portions of the contorted gneiss are represented. |

chlorite and other decomposition-products, but there is no doubt
that they were originally diorite. The shape of the masses indi-
cates that they have been compressed by a force acting vertically.
The direction of the foliation in the grey gneiss is determined by
the dark blocks. It bends in between them, and curves outward
where they project, just as if a high-dipping foliation had been
contorted by the vertical pressure.

(2) Gneiss of Secondary Injection.

Excellent examples of this kind of gneiss are seen in the Llangaffo
cutting. Near the eastern end is exposed a mass of dark rock
about 25 yards wide, with grey gneiss on each side of it (fig. 3, p. 356).
In the centre the dark mass is normal diorite, but towards both
margins it graduates into a chloritic micaceous gneiss. The eastern
margin is nearly straight, hading at a high angle to the west, and
the grey gneiss in contact has the foliation coinciding in direction

22

356 DR. C. CALLAWAY ON THE ORIGIN OF [Aug. 1897,

with this hade. On the western side the altered diorite is very
irregular, projecting into several promontories; but here also the
grey gneiss is foliated parallel to the margin of the diorite, the
laminee following exactly the projections and recesses of the latter.
This foliation is accentuated by very thin dark lines.

Fig. 3.—Gneiss of secondary injection, Llangaffo.

< =~
a KES 8
ay x
=—y Ss DIORITE
VZ2AAA
GZ = PASSING INTO
iS)
3 ScHIST
| S
Le
GNEISS GREY GNEISS

[The grey gneiss or sheared felsite is injected with decomposition-products from
the adjacent diorite. The black lines in the grey gneiss represent planes
of injection, but only a few are shown. |

The explanation of this gneiss is similar to that which I have given!
of an infiltration-gneiss at Malvern, felsite being substituted for
granite. The infiltration-products are substantially the same as at
Malvern, consisting mainly of chlorite, iron-oxide, and epidote; and
out of the chlorite and iron-oxide, with the addition of materials
from the feisite, black mica has in like manner been sometimes
constructed. The following is a description of a slice of this gneiss.
It shows a breadth of 2 inch cut across the foliation, and is taken at
the junction of the erey gneiss with the altered diorite.

1. Aseam of minute transparent granules, generally elongated in
the direction of foliation, many of them being lenticular in
shape. It is rarely possible to determine which of these
are quartz and which felspar, but scattered among them are
several comparatively large lenticles of quartz. Some minute
erystals of epidote, elongated with the foliation, are present.

A dark seam, chiefly composed of interfelted chlorite, pale green
in ordinary light, almost extinguishing under crossed nicols.
It occasionally passes into greenish, or even brownish, mica.
There is a little epidote, and lenticles of clear quartz or felspar
lie amid the meshwork.

A minute interfoliation of several of the felsitic seams with the
dark green material.

A comparatively thick folium of the chloritic rock.

Veins of calcite cross the slide transversely to the foliation.

bo

aes

This specimen may be taken as typical of the structure at the
junction of the grey and green rocks. It does not contain much
mica, but in some of the junction-slides there is a fair proportion
of that mineral, the white variety being predominant.

1 Quart. Journ. Geol. Soc. vol. xlv. (1889) p. 496 & vol. xlix. (1893) p. 412.

Wol.’53:)] SOME OF THE GNEHISSES OF ANGLUSEY. 357

That the foliation of the grey gneiss should follow the margins
of the diorite is not difficult to explain. When the rocks were
sheared the diorite was a dyke-like mass with nearly vertical sides,
and the foliation in both felsite and diorite was parallel to them.
A vertical pressure subsequently distorted the western margin, and
at the same time contorted the gneiss in contact, compelling its
foliation to follow the outlines of the diorite.

The distance from the diorite to which the chlorite, etc., are
injected varies considerably. Where the shear-planes are numerous
and close the rock is very permeabie to liquids, and a considerable
fringe of dark-lined gneiss is the result. This variety of injection-
gneiss is sometimes seen where no basic rock appears in proximity,
though of course hidden masses of it may be near.

I need hardly point out that the genesis of this kind of gneissic
structure in the felsite was posterior to its consolidation, since
planes of discontinuity could not have been produced in a fluid or
plastic magma. It is further to be noted that the gneiss is some-
times traversed by irregular cracks, and that the infiltrated liquids
have passed into these cracks as well as into the shear-planes.

The diorite also must have been in a solid state at the time of
injection. It is not molten rock that has been injected into the
grey gneiss, but the products of decomposition, such as are caused
by the passage of liquids through a crushed solid.

SuMMARY.

1. The gneisses described in this paper have been formed out of
plutonic igneous rocks by crushing and shearing subsequently
to their consolidation.

2. Occasionally the process has been accompanied by a partial re-
melting of the rock.

3. The most interesting varieties of gneiss have been produced
where there has been a complex of diorite and felsite, primary
injection giving rise to banded gneiss, and secondary injection
accentuating gneissic structure in sheared felsite by dark lines.

4. Simple gneisses have been formed out of granite, diorite, and
felsite respectively, the last-named originating the well-known
grey gneiss of Southern and Central Anglesey.

5. The so-called halleflinta is merely the felsite in the first stage of
conversion into gneiss.

Discussion.

The Prestpent said that the Author was doubtless right in
regarding the older pre-Cambrian rocks in Anglesey as formed from
a great igneous complex ; but it was difficult to say in all cases how
and when the gneissic structure had been produced. As to the
blocks of diorite in gneiss, shown in fig. 2 (p. 355), he thought it
possible that they might be broken portions of a thin dyke, the
result of pressure and crushing, rather than masses of rock caught up

358 _ DR. C. CALLAWAY ON THE ORIGIN OF [Aug. 1897,

in fluxion. The paper opened up numerous questions of considerable
importance.

Prof. Bonnzy said that for many years he had been working in
other regions in the hope that he might understand districts like
Anglesey. There we had to bear in mind that we were dealing
with rocks which originally had structures of their own, and had
had structures impressed on them. These he thought the Author
had not always distinguished. As for the included blocks of diorite
in the grey gneiss it was difficult to say what was the explanation ;
for the diagram would bear more than one. He thought it impos-
sible that the specimens of gneiss exhibited could have been formed
from a felsite. He doubted whether chlorite could be converted
into mica except in cases of contact-metamorphism. But no doubt
many changes had taken place in our views during the last twenty
years.

The Rev. J. F. Brake was glad on this occasion to agree with
all the remarks of the last speaker, especially upon the larger
erystals of the gneisses supposed to be derived from a fine-grained
felsite. He also agreed with the Author that in the distortions of
the rocks it was quite possible that rifts might be made that were
now filled by a different crystalline material from the neighbouring
rock, or into which felsite was intruded in thin sheets, thus making
the Author’s ‘gneisses of primary injection’; or where a diorite
was intrusive, as at Llangaffo cutting, materials from it might easily
be, and no doubt were, carried by water and deposited between the
folia of the adjacent gneisses, thus making the Author’s ‘ gneisses
of secondary injection.’ But in both cases the phenomena were
purely local—limited in fact to a few feet or inches, and threw
no light upon the general mass of gneiss which covered many square
miles of country. With regard to the so-called ‘ diorite-blocks,’
they were simply the ends of offshoots from some larger mass of
diorite which had been subsequently distorted.

As to the Author’s ‘ felsite,’ the speaker was entirely at variance
with him. Itis true that a microscopic section of it was examined by
some eminent petrologists at the British Association Meeting in 1887,
and pronounced to be felsite, and this the speaker regretted ; for, as
it was perfectly clear to him on stratigraphical grounds that the
rock was not a felsite, he could only conclude that it was impossible,
by the microscopical examination of a rock-section, to ascertain
whether or not that rock was a felsite. He showed, however, the
locality of this supposed felsite to a large number of foreign
geologists after the International Geological Congress in 1888, but
none of them suggested that the rock was a felsite. It is true that
the rock referred to by the Author is very fine-grained and resembles
a felsite—and that it passes by insensible gradations into the ordinary
grey gneiss; the phenomenon is, however, a purely local one, and
over many square miles of country there is no sign of such a felsite-
mimicking rock; but the folia of the gneiss are clear and parallel.
The specially compact appearance is limited to the neighbourhood
of, and is probably due to the pressure from, the largest dioritic

Vol. 53.] SOME OF THE GNEISSES OF ANGLESEY. 309

intrusion of the district; and in just the same way the ‘ hilleflinta’
which borders the exposed edge of the great granitic intrusion of
the centre is due to the pressure of that mass, which has pounded
the earlier gneiss into the minutest fragments, as already pointed
out by Prof. Bonney and agreed to by the speaker. If we were to
regard the so-called ‘felsite’ as the normal rock from which the
gneiss had been derived, it would be very remarkable that it should
be found in its most unaltered condition exactly at those spots
where it must have been subjected to the greatest amount of
pressure. The origin of the gneiss appeared to the speaker to be
still an entirely open question, though he was not disposed to regard
it as igneous.

Mr. Marr did not quite understand how the occurrence of irre-
gular blocks of dioritic rock in the gneiss of Llangaffo proved the
intrusive origin of the latter. Judging from the diagram, he could
well imagine that the dioritic blocks might be dissevered portions
of a folded dyke of diorite, though he did not wish to press this
explanation as the correct one.

360 | |) (CaPnl HS GR LYONS! ON THES ~ { Aug. 1897,

27. Nore on a Portion of the Nusian Desert sourH-East of
Korosxo: I. Frerp Grotocy. By Capt. H. G. Lyons, R.E.,
F.G.8. II. Perronoay. By Miss C. A. Raisin, B.Sc. (Com-
municated by Prof. T. G. Bonney, D.Sc., LL.D., F.B.S., V.P.G.S.)
III. Warer Anatyses. By Miss E. Aston, B.Sc. (Jdem.)
(Read April 28th, 1897.)

[Pare XXVI—Map.]

I. Fre_v Gronoey.

In the month of December, 1894, while on a military patrol in the
Nubian Desert to the south and east of Korosko, I was able to
examine a portion of this area which has not previously been
described. Linant de Bellefonds, in his ‘ L’Etbaye,’ and Col. Colston,
of the Egyptian General Staff, have given short accounts of the
rocks met with on the Korosko-Abu Hamed caravan-road, while
the traveller Burckhardt 1 in 1814 passed by Bir Ongat, and then
rather to the east of the area now described, along the Berber road.
From these different accounts it seemed that the Nubian Sandstone
of this part reached as far east as long. 33° E. of Greenwich, but
the topography of all this part was very inaccurate, and the object
of the patrol was to correct this. Surveying and marching from
22 to 25 miles a day gave little time for geological investigation,
and all that was possible was to indicate the boundary-line between
the Nubian Sandstone and the crystalline rocks, and to form a small
collection of specimens from the latter.

A set of microscope-slides has been prepared from 33 of these and
submitted to Prof. Bonney, F.R.S., under whose supervision they
have been described by Miss C. A. Raisin, B.Sc., at University College,
London. In the sketch-map attached to this paper (Pl. XX VI) no
attempt has been made to distinguish the minor varieties of rocks
which occur in this district; but the Nubian Sandstone, and the
crystalline rocks respectively, have been indicated, as well as one or
two areas where schistose rocks are especially developed.

(1) General Description.

Between Korosko and Siala the Nile runs through a comparatively
narrow channel excavated in the Nubian Sandstone, which here on
the eastern bank forms cliffs some 200 feet in height descending to
the water’s edge, while on the western bank the sandstone desert,
with its patches of drift quartz-sand, rises more gradually and does
not attain to the height of the eastern plateau.

Cultivation is restricted to small patches and strips; while in
places the foot-track passes through the hills, since there is no room

1 «Travels in Nubia.’

Vol. 53.] GEOLOGY OF PART OF THE NUBIAN DESERT. 361

at the base of the cliffs by the river. This lowest part of the great
plain of Nubian Sandstone is at Korosko about 380 feet above the
Mediterranean, and it rises to about 1700 feet at the foot of Jebel
Raft in the eastern desert, while in the western desert much lower
altitudes are met with, and the plateau 100 miles south of the oases
of Kharga and of Dakhla has only attained an altitude of 500 and
800 feet respectively.

The caravan road from Korosko to Abu Hamed, which passes by
the Murrat Wells, ascends for the first 50 miles through the sand-
stone plateau and finally comes out upon the high plateau, passing
through a gap in the escarpment which overlooks the former plateau
at the Bab el Korosko. ‘This is approximately 1600 feet above sea-
level. The higher plateau is a gently undulating plain with isolated
hills of sandstone, and it drains to the east into the Wadi Kabkaba ;
this in its turn joins the Wadi Allaki, which meets the Nile at
Siala.

To the south and east this plain is bounded by hills of crys-
talline rocks, against the flanks of which the sandstone has been
horizontally laid down.

(2) The Crystalline Rocks (massive and schistose).

Coming from Korosko to the Murrat Wells the crystalline rocks
are first met with in the Wadi Mogharin on the east side of Jebel
Raft, which seems to consist mainly of granite, diorite, etc., while
the Nubian Sandstone is laid down horizontally on the flanks of
these on the north side. It is possible that Jebel Khatab el
Atshan may be an outlier of these crystalline rocks; this is
inferred from the appearance of its black summit rising above the
sandstone which forms its lower slopes, and also from the statement
of the Arabs that there is a rainwater-reservoir in this hill. On the
south and east side of Jebel Raft there is an area of low ground
occupied by schists, dipping at various angles from 40° to vertical,
and much intersected by dykes. Those south of Jebel Raft have a
direction of strike which varies a few degrees on either side of east
and west, while those to the east of this hill and in the neighbourhood
of Jebel Banat Raft and Kageritbar have a distinct north-and-south
strike, which is continued until the massive crystalline rocks of
Tilat Abda are reached.

The schists occur on the south side of Jebel Raft and at a short
distance to the north of Murrat Wells, but are seen in their greatest
development between this place and the west side of Jebel Raft.
Here, in the Wadi Om Nabadi, are the ancient gold-workings which
are indicated by Linant de Bellefonds in his map of the Etbai. The
valley is crowded with ruins of small circular huts, about 63 feet
in diameter, built of loose rubble-stone, which were the dwellings
of the workmen, and the lower part of a granite hand-mill lay near,
but this probably was for grinding corn rather than for crushing the
rock, for that was done with rubbing-stones about 3 to 4 pounds in
weight. J had not time to make a very detailed examination of

362 CAPT. H. G. LYONS ON THE [Aug. 1897,

the spot, but the small size of the stones used and the piles of coarse
broken (but not crushed or ground) quartz lying about would lead
one to think that the schists rather than the quartz had been
worked as the source of the metals, the quartz having been thrown
aside as rubbish. I could see no signs of gold in the pieces of quartz
which I examined. At this part the strike of the schists and of
the veins of white quartz is W.S.W.—E.N.E.

North of Bir Tilat Abda, and as far as Bir Ongat, the massive
crystalline rocks alone are seen, while to the north of Bir Ab Araga
is a very large exposure of greyish-red granite. Not until north-
west of Bir Ongat do the schistose rocks again appear, and along
Wadi Nayit their strike coincides generally with the direction of
the wadi (from N.-S. to N.N.W.-S.S.E.), while granite forms a
low chain of hills to the west.

Down the Wadi Allaki, which takes all the drainage of this part,
schistose rocks alone appear, having a strike generally at right angles
to the valley, that is, N.E.-S.W.

(3) Pre-Cretaceous (?) Conglomerate.

On the crystalline rock-mass of Jebel Raft, and apparently over-
lain by the Nubian Sandstone, there is a very coarse conglomerate
formed of fragments of the crystalline rock, both rounded and
subangular, with intercalated patches of sandstone here and there.
The rainwater-reservoirs of Wadi Mogharin occur in this rock.

It was not seen elsewhere, so that its true position could not be
determined, but it appeared to be older than the Nubian Sandstone
which was seen lying close to it (if not overlying it). The latter,
however, has a basal bed of quartz-conglomerate with pebbles of
no great size and very different in appearance from this coarse
conglomerate.

(4) The Nubian Sandstone.

The Nubian Sandstone is laid down on the flanks of the crystalline
hills, with little or no dip. It shows very slight variation in
composition, being a quartzose sandstone of different degrees of
fineness, passing from a pure white colour through all the shades
of yellow, brown, and red, from staining by oxides of iron and
manganese. Black nodular concretions of sand cemented by these
minerals are very common, and, in consequence of their power of
resistance to weathering, lie everywhere on the surface of the desert.
Sometimes a more argillaceous bed is seen, but it has no great
extent, and no beds could be found sufficiently constant to be of
any stratigraphical value. No rock was anywhere seen intrusive in
the sandstone. |

The main obstacle in traversing the Nubian Desert is the want of
water and the uncertainty of finding a sufficient supply at any of the
wells. Unlike the western desert, where the water is derived from
deep-seated sources, and the supply, though only available at a few

¥ol.'53-] GEOLOGY OF PART OF THE NUBIAN DESERT. 363

places, is abundant, the water of the Nubian Desert is directly
dependent on the rainfall. This is irregular and may not occur for
several years, during which time the wells become very low and their
water strongly saline.1 The sources of supply in this Nubian Desert
are two:—firstly, from wells (Bir), and secondly from reservoirs
(Makhzan).

The first of these are sunk to a depth of from 8 to 20 feet in the
detritus of the valleys, and are fed by the water which percolates
into them from the neighbouring rocks, being full after heavy rain
and diminishing as the drought continues. As a consequence, nearly
all these wells contain a considerable amount of mineral matter
in solution, and the waters of some are almost undrinkable.

Rounded boulders in pot-hole, reservoir of Wadi Om Risha
(Jebel Raft).

[Height represented in figure = about 20 feet. ]

The second source of supply, the rainwater-reservoirs, are deep
holes in the gullies and ravines which intersect the crystalline hills ;
these are filled by rainstorms, and as they are partly screened from
the sun by the steep side of the ravine they often retain the water
for nearly a year. Some of these in Jebel Raft are of considerable
size, that in the Wadi Om Risha being 33 x 44 x 20 feet in cubical
capacity. The origin of these deep holes worn in the ravines must
be attributed to water-action, and in the reservoir of Medina in
Jebel Raft lie the rounded stones which have assisted in forming this
pot-hole. (See the accompanying figure.) It is hardly conceivable
that this has been effected by the rare, though often violent, rain-
storms of the present time, and it must, I think, be attributed to
an earlier period when the rainfall was heavier and carved out the
ravines and valleys which we see at this day. Similar rainwater-
reservoirs occur in the hills on the western coast of the Red Sea.

1 Within the last few years the only rains capable of filling all the wells in
the neighbourhood of Murrat fell in November 1891 and August 1896. In
this long interval only a few showers fell.

364 MISS C, A. RAISIN ON THE PETROLOGY [ Aug. 1897,

Il. Prrrotoey.
By Miss C. A. Raisin, B.Sc.

The collection of specimens sent by Capt. Lyons includes many
rocks of similar class, but I have given short notes of all, as they
represent a district on which no petrological information is available,
and they show some variations. I have to thank Prof. Bonney for
much kind help in my investigation.

In order to avoid repetition, the specimens have been grouped
petrologically. Those in Groups vii & ix come from the ‘schistose’
area, but the majority are from the areas marked by Capt. Lyons as

sedimentary. The ‘crystalline’ districts may be described as (1)
the ‘Southern’ (around Murrat), and the ‘ Western’ (around Jebel
Raft) separated by the southern tract of ‘schistose’ rocks; (2) an
‘Kastern’ district beyond the schistose outcrops just mentioned,
extending over the watershed to the head of the Wadi Allaki. Of the
crystalline rocks, those which bear most distinct signs of modification
are treated first.

(1) Gneiss.

(18': Murrat, from the Southern area). Of this only one specimen
occurs ; it is jointed, and has a rather fragmental aspect.— Microsc.
The original constituents are often reconstituted. The quartz forms
a clear mosaic enclosing minute zircons and other prisms. The
clustered felspar-crystals or grains (sometimes plagioclase and
somewhat idiomorphic) are altered, and may be bordered by minute
mica; and a small amount of a green, rather dichroic, altered
biotite occurs with some ferrite. The rock is a fine-grained biotite-
gneiss, which appears to be granitic in its origin, probably somewhat
pressure-modified, but it possibly bears traces of a slight original
banding.

(1) Hornblendite.

(7: Abu Sinaiyat, in the Southern area.) <A greyish-green
schistose rock of rather friable actinolitic hornblende.—Merose.
The crystals are pale green, often iron-stained, scarcely dichroic,
well cleaved, and resemble the small prisms of secondary hornblende
in many of the otber rocks. The mineralis orientated. The macro-
scopic aspect suggests pressure-modification, and the microscopic
would accord with it.

(iii) Altered Gabbro or Dolerite, Diabase, etc.

(a) Altered Gabbro.—Several rocks, all coming from the southern
area, are evidently altered forms of gabbro (11, 15: Murrat; 10,
19: Abu Sinaiyat). In three specimens (11, 10, 19) the mineral
constituents are almost entirely changed into an actinolitic aggregate
and a mass of zoisite with some epidote, but diallage can be recog-
nized in one rock (11). In this the hand-specimen shows abundant

1 The numbers are those attached to the specimens by Capt. Lyons.

Vol. 15 3:.| OF THE NUBIAN DESERT. 365

felspar, whitish and fatty-looking, and grass-green pyroxene or
amphibole with one cleavage and a well-marked form. The appear-
ance recalls that of some Alpine gabbros.— Microsc. Diallagoid and
hornblendic cleavages, and sometimes twinning, are seen in the
greenish mineral in the midst of a felted hornblendic mass. The
rock bears no definite signs of crushing. In 15 the green mineral
(less in amount) is partly now a chloritic aggregate, partly a
yellowish-green, non-dichroic product which seems flaky as if
derived perhaps from diallage. The edges are corroded by the
surrounding mass. Much of the felspar is clear and is plagioclase
(labradorite), but secondary minerals are developed.

Nos. 10 and 19 are mottled greenish and grey, with small
patches which are jade-like in appearance. The former specimen
is bounded by joint-planes, the second has a sand-worn surface.—
Microsc. In both, the mineral constituents are replaced, but in 19,
where the grains are larger and clearer, actinolite is grouped in
curving sheaves, suggesting the possibility of pressure-effects. In
10 two or three isolated, fairly large crystals of a brownish dichroic
mineral (pale to cinnamon-brown) with bluish dusty centre, probably
are tourmaline. They terminate irregularly, enclose foreign sub-
stances, and appear to be a late formation, and to have grown across
the hornblende-zoisite aggregate, almost eating it up, as the mica
described by Prof. Bonney across a schist." The form, however,
would be unusual for tourmaline in a rock of this kind, and it may
be not only secondary but 2lso pseudomorphic.

(b) Diabasic Rocks with Lustre-mottled Hornblende.—16 (Murrat)
is from the Southern, and 1 (Tilat Abda) & 33 are from the
Eastern region. In all, well-cleaved blackish or dark-green lustre-
mottled hornblende is associated with felspar, which is greenish-
white saussuritic-looking in 1 or an opaque white in 16.—
Microsc. The felspar is replaced by a micaceous or kaolin aggregate
with flaky yellowish viridite, or pseudophite. and granular epidote,
some oligoclase remaining in 1. The hornblende is dichroic,’ has
colourless and other patches, and where the differences are most
marked, as in 33, the varieties apparently pass into each other by
secondary change. It encloses grains of felspar often altered ; also
in 1 some pyroxenic grains and some of granular calcite, but there
appear to be gradations between these, as if the pyroxene might be
a lime-pyroxene—a malacolite—such as occurred in the picrite of
St. David’s described by Prof. Bonney.? Clustered epidote and
scattered actinolite are abundant. In 33 iron-oxide, a few zircons,
apatite, and epidote occur, and a quartz-vein. Much of this slide

consists of dusty felspars, broadly oblong, closely set in a ground of
coarse quartz.*

1 «On a Secondary Development of Biotite and of Hornblende....... » Quart.
Journ. Geol. Soc. vol. xlix. (1893) p. 104.

* In 1 e, pale brown; b, dull olive-green ; a, reddish brown to green.

3 Quart. Journ. Geol. Soe. vol. xli. (1885) p. 519.

* JT incline to the view that the rock is akin to the diorites, notwithstanding
the form of the felspars; and from the character of the hornblende, it seems
best described here. Compare also Nos. 4, 30, 27, infra, pp. 366, 367.

366 MISS C. A. RAISIN ON THE PETROLOGY (Aug. 1897,

(c) Other Hornblende-diabases.—(4, 20, 9,13, 2, 14.17, 5, 25.) In
one specimen from the west (4: Jebel Raft, west side) and in five
specimens from the south (Murrat: 20, 9,13, 2,14), where minerals
are recognizable, felspar and hornblende in various stages of alteration
are the chief components, and on the weathered surfaces the latter
may be etched out (4, 2).—Microsc. The felspar exhibits plagioclase
structure either in the interior or as a rim; and in most of the
rocks interstitial clear quartz or secondary feispar is present, some of
which may be traced in No. 4 originating at the exterior of certain
crystals, and even connected with a kind of micropegmatitic
structure.’ The hornblende in some cases is markedly idiomorphiec,
and exhibits a change from the brown to a green variety,’ as
in the mottled crystals in 20 and 13. In 9 the large idio-
morphic hornblende is entirely replaced by streaky serpentinous or
chloritic mineral with small included crystals ; in 4 it is partially
replaced by filmy viridite. In the former rock some of the enclosures
are iron-oxide ; but the most interesting are very numerous prisms
of rutile (and perhaps pseudobrookite), which sometimes are related
in their position to the principal cleavages of the hornblende.? In
20 a light-coloured part beyond a sharp straight boundary of the
hornblende-crystal is probably an added growth.* Specimen 2,
somewhat bounded by joint-planes, greyish-green, and externally
brownish, shows under the microscope aggregates of chlorite
apparently replacing pyroxenic crystals, and yellowish, slightly
dichroic flakes, probably altered biotite, and some approaching viridite
in character. In the microlithic groundmass are granular epidote,
calcite, and iron-oxide. Clustered rutile seems to have formed within
ilmenite which is now replaced by leucoxene, or within sphene,
and in 13 sphene is apparently derived from ilmenite. No. 14 is an
iron-stained, compact rock which exhibits (microscopically) a very
irregular mosaic of plagioclase, quartz, colourless chlorite, and a
high-refracting mineral giving a peculiar blue with crossed nicols.
It includes grains small and large (some j, inch in diameter) of a
carbonate with a green rira, and of hematite or limonite. Corroded
remains of larger plagioclase-felspars occur. These two rocks have
undergone much change, and 141s somewhat crushed, but they were
probably felspathic dolerites or diorites.

Two rocks also from the Southern region (5, 17: Murrat) are
fine-grained and are difficult to identify. No.5 is a dark-grey rock,
with an interrupted silky look due to minute crystals, and with small
brownish projections on the surfaces smoothed and pitted by sand-
action.— Microsc. The knobs consist of a quartz-mosaic coloured by
a brownish carbonate. The cryptocrystalline sericitic groundmass

1 The rock reminds me somewhat of specimens examined from the Nile
Valley and from West Africa. See also Geol. Mag. 1893, p. 456; compare
Nos. 27 & 30, infra, p. 367.

2 Like the change in certain picrites. See T.G. Bonney, Quart. Journ. Geol.
Soe. vol. xli. (1885) p. 520.

3 Compare the rutile within serpentinized olivine, ‘On the ......... Rauenthal

Serpentine,’ Quart. Journ. Geol. Soe. vol. liii. (1897) p 253.
* See Whitman Cross, Am. Journ. Sci. ser. 3, vol. xxxix. (1890) p. 360.

Vol. 53.] OF THE NUBIAN DESERT. 367

might be derived from a felspathic substance, and numerous brown-
stained, greenish, dichroic flakes or prisms occur. The rock has
rather the aspect of a mica-trap, but some of the last-named
constituent seems to have an oblique extinction, as if it were
hornblende rather than.biotite. No. 17 has a modified felspathic
ground somewhat similar to 5 (with calcite, quartz, limonite, and
minute ?kyanite); but it is penetrated by strings of small horn-
blende, and encloses large porphyritic felspars, and probably altered
representatives of others. These form whitish oblongs in the pale
greenish hand-specimen, which exhibits a platy structure, and the
rock might be called a hornblende-schist, but is probably a modified
diorite.

In 25 (Tilat Abda) from the Hastern area, we return rather nearer
to the type of 2or14. Itisa greyish rock crowded with small,
white, irregular felspars.—Mvcrosc. These are dusty-looking, and
other crystals, doubtless pyroxenic, consist partly of yellowish,
generally isotropic substance. As in 2, an interstitial clear mineral,
granular epidote, calcite, and iron-oxide are present.

From the Eastern area also come four other specimens of rather
different types (29, 26, 30, 27).

(d) Porphyritic Diabase (29).—A dull greenish rock, sand-polished
and somewhat crushed.—Microse. The porphyritic crystals are large,
lath-shaped, rich green, and irregularly terminated. They are
replaced by chlorite, epidote, granular secondary felspar, sometimes
deposited as if along cleavage-planes ; if these were felspar originally,
they have developed an exceptional amount of chlorite. The
groundmass is almost completely masked by granular epidote.

(e) Diabase with remaims of Augite (26).—Only one rock in the
collection exhibits augite partially unaltered occurring as porphy-
ritic crystals, and even here hornblende forms the ferromagnesian
constituent of the groundmass. Doubtless in many of the rocks
augite was originally present, the hornblende being secondary.
This specimen is dark greenish-grey, slightly speckled, containing
narrow, white, porphyritic felspars, sometimes in radiating clusters,
and some iron pyrites.— Microsc. The felspar is kaolinized; the
augite sometimes well-preserved, occasionally twinned along 100;
but generally the crystals are changed—along the borders or
completely—to fibrous hornblende. Clusters of similar actinolite
with a carbonate and iron-oxide are found. The groundmass
includes labradorite, and gummy brown mica-like hornblende
passing into green actinolite. The rock, originally a minutely
erystalline dolerite, now is rather a hornblendic diabase.

(iv) Quartz-diorite.

In 30 the quartz is not, perhaps, in sufficient amount to justify
this term, but it leads up to the better-marked type (27). The
former consists of flesh-coloured or greenish felspar and of blackish
hornblende with a little quartz.— Microsc. The plagioclase-felspar
is intererystallized with a mosaic, the grains exhibiting a kind of

368 MISS C. A. RAISIN ON THE PETROLOGY [Aug. 1897,

micropegmatitic structure. This may show finger-like divisions
radiating in tufts, or two sets of them at right angles forming a
kind of basket-work, but usually the structure is less regular.1 The
hornblende is dichroic (myrtle-green to pale greenish-yellow), not
idiomorphice or fresh-looking, associated with some altered biotite.
Iron-oxide, epidote, ? apatite, besides quartz, are present. The
rock originally may have been a diorite.

No. 27 is a pinkish-white fine-grained rock.— Microsc. The fel-
spar is plagioclase; the quartz forms a mosaic, containing lines of
cavities and acicular microliths which extend through adjacent
grains. The rich green dichroic hornblende,’ with twinning along
100, encloses grains of quartz or felspar. Iron-oxide (? ilmenite),
epidote, and impure-looking sphene occur. The constituents are
all rather irregular, and the rock appears to have been somewhat
affected by pressure followed by reconstitution.

(v) Granite.

One specimen from the Western area (3: Jebel Raft, west side, by
Wadi Tonaidba) consists of quartz (projecting on weathered surfaces),
of much pinkish felspar, and of a reddish-black iron-oxide.—Mierose.
The felspars are idiomorphic, kaolinized, but at places apparently
plagioclase. In the interstitial quartz are lines of enclosures. Veins
also occur which are in mineral continuity with the quartz where
they pass through it. The hematite or limonite replaces fairly large
crystals which are posterior to the felspar, but resemble pyroxene,
and are similar to the replaced pyroxene (?) in rocks, probably
doleritic, from Abu Seir and West Africa.’

(vi) Felstones.

Two rocks from the Eastern area appear to be cryptocrystalline
forms of an intermediate or acid type. No. 31 is jointed, with rather
polished surfaces. The rock is brown and flinty-looking, speckled
with white porphyritic felspar-crystals, partly corroded.—Merose.
A second generation of small felspars helps to form the ground-
mass, which includes small green, dichroic, micaceous, or chloritic
flakes and black iron-oxide. The rock probably is a compact
quartz-felsite.

No. 32 is pale grey, with numerous whitish porphyritic felspars,
often idiomorphie, like orthoclase in shape, but altered, with various
enclosures— micaceous, pyroxenic, and others. A vein filled with a
carbonate occurs. The devitrified groundmass, abundantly micro-
lithic, has a fluxional look, and the rock is a felsite probably slightly

affected by pressure.

1 Although a similar formation in other rocks may be original, this suggests a
secondary deposition along cleavage-planes, resembling the ‘ quartz de corrcsion ’
of Fouqué & Lévy, ‘ Min. Micr.’ (Mém. Carte géol. France, 1879) p. 193.

2 a, myrtle-green; b, olive-green; ¢, pale brownish-green.

3 Geol. Mag. 1893, p. 441.

Vol. 53.| OF THE NUBIAN DESERT. 369

(vii) Rocks of Igneous Character, but Uncertain Origin.
(‘Schistose’ area: 21, 24, 23.)

(21) Wadi Om Nabadi; (24) Jebel Banat Raft. Two rocks from
different parts of the southern schistose area bear some resemblance
to each other. Both are pale greenish, with fine-grained structure
developed, probably by wind-erosion, on the weathered surface.
They have a slight appearance of schistosity ; and one rock (24)
exhibits apparent fragments separated by vein-like parts rich in
epidote.— Microsc. Both rocks include worn and sometimes rounded
plagioclase-crystals ; the intermediate part being much masked by
epidote and other secondary minerals. In all the constituents
microlithic enclosures have formed, often of small flakes of chlorite,
of which mineral larger crystals also occur in the slide (dichroic,
changing from green to yellowish). Much scattered iron-oxide is
found. While some of the microscopic fragmental appearance is
probably due to subsequent disturbance or crushing, some of it is
probably original. The rock (21) seems certainly a diabase-grit or
ash, with inclusion possibly of some andesitic or felsitic fragments ;
while 24, although it may have been also originally clastic, has more
resemblance to a true igneous rock. The sp. gr. of 24 is 2°77.

(23: Om Nabadi) is a dull greenish-drab, finely-speckled schistose
rock, in which the plagioclase-crystals are broken and corroded.
The felsitic groundmass contains greenish microliths (more abundant
along iron-stained streaks), a carbonate, limonite, ? chalybite, ? epi-
dote, and black iron-oxide. The brown mica includes small scales
changing to green, and larger, clearer flakes, transverse to the
foliation, which thus appear to be secondary, like those described
by Prof. Bonney in an Alpine schist.1 Green dichroic flakes
occur, probably derived from certain of these larger mica-crystals.
The clearer areas, enclosed within greenish stringy lines, appear, on
microscopic examination, to be like normal felsite, and the rock,
which looks finely fragmental, may owe this appearance to crushing,
and may be a squeezed porphyrite. The sp. gr. of one fragment
was found to be 2°71, which would agree very well with this
identification.

(viii) Sedimentary Fragmental Rocks.

One rock from the Southern area is an impure limestone (6:
Murrat, 8.). A strong, compact, dark grey rock, with a somewhat
foliated look, containing small, elongated, slightly irregular, silvery
flakes, very definitely orientated. The rock effervesces briskly with
hydrochloric acid, is a quartzose or gritty limestone, indurated, and
from the flaky laminze has the appearance of being pressure-modified,
but this character cannot be well recognized in the microscope-slide.
One surface is sand-worn.— Microsc. Calcite, the chief constituent,
is dusty with opacite (? carbonaceous), and is interrupted by nests
of impure limonite. The included fragments consist of quartz, of

* Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 104.
Q.8.G. 8. Nov211, 2c

370 MISS C. A. RAISIN ON THE PETROLOGY [Aug. 1897,

plagioclase, some of (?)felsite. Minute flakes of white mica are
scattered within or around the fragments, or form wavy patches,
the silvery scales being seen macroscopically.

This specimen, brought from the area of ‘crystalline’ rocks, has
' more affinity with those of the ‘schistose’ region, and resembles
certain squeezed muddy limestones of the Alps, which probably are
Jurassic in age.

(ix) (?) Phyllites.

(21,* 22: Wadi Om Nabadi. From the ‘Schistose’ area.)
These two specimens are schistose rocks with silvery-sheen sur-
faces, somewhat iron-stained, partly in connexion with rusty cubic
crystals.— Microsc. The fine-grained clear mosaic is crowded with
pale green micaceous (?) microliths, often orientated, and sometimes
matted along wavy lines. In 21* one rather large crystal, now
limonite, has a border of coarsely crystalline quartz, almost cubic
in outline. Fine-grained quartz-veins traverse the slide. It is not
easy to decide whether these two specimens are crushed, some-
what gritty phyllites, or much-cleaved schist, like certain Alpine
rocks, Although in the slice from 22 a crystalline character seems
slightly more evident, the rocks which have been crushed were more
probably not true schists. The two specimens might well come
from the same rock, and scarcely represent even different bands.

A quantity of cubes of a rich brown colour were collected on the
hill of Kageritbar, where it was crossed by Capt. Lyons’s route. The
mineral is limonite, but is no doubt a pseudomorph. The crystals
are generally from 7 to 2 inch across, and they were probably
formed in situ, since in an accompanying fragment of rock are
similar cubes, but much smaller (about ; inch). These crystals
often have closely-fitting quartz, which builds up a regular partially
cubic form, as if it were a vein-like growth similar to that described
in slide 21,* and at one part like ‘ faser-quartz.’ The loose cubes
often exhibit associated quartz. Thus it seems as if the formation
of the cubes may have induced crystallization and deposition of silica
around them. In the slice of this rock, micaceous microliths are
not recognizable, but the fine granular mosaic of the groundmass
seems to be similar to that in the preceding specimens, although
here it is very much masked by patchy limonite. By the kindness
of Prof. Bonney, I have looked for comparison at slides of the Ober-
mittweida rocks,! which exhibit a micromineralogical change far
more marked, but apparently of the same type.

(x) Vein-quartz.

(8, 12: Abu Sinaiyat.) Two specimens from the Southern area
are hard, compact, sand-worn rock, speckled with minute metallic —
grains, and weathering brown. They have a brecciated look, the
fragments, black in colour, tinged violet in places, being separated
by whitish veins of composite quartz, larger in 12.—Microsc.
Fragments of the original vein-quartz are large, irregular, but

1 See Quart. Journ. Geol. Soc. vol. xliv. (1888) p. 25.

Vol. 53-] _ OF THE NUBIAN DESERT. 371

elongated and orientated. In these the opaque metallic hematite (?)
is disseminated in fine particles, but it is aggregated as crystals or
thicker streaks among the cementing secondary quartz. In 12
the grains of the mosaic are larger, more sharply defined, more
-erystal-shaped, and freer from opacite.

SUMMARY.
1. Classes of Rocks.

With the exception of two or three felstones, the igneous rocks
-are holocrystalline. One is apparently granitic, and one gneiss may
be a modification of an igneous rock, but the great majority belong
to a rather basic or to an intermediate type, and are generally much
altered ; they are diorites, diabases, dolerites, or gabbros. Of none
-of the rocks can we say with certainty that it originated as a
lava-flow, only a slight indication of fluxional structure being found
in one felstone, and certain specimens (such as the gabbro and the
granite) doubtless can only be from intrusive masses; the mode of
occurrence of others must be decided by field evidence.

The few fragmental rocks come from the ‘ Schistose’ area, except
one gritty limestone apparently caught in among igneous masses.
Two are much crushed, probably phyllites ; and one at least consists
chiefly of igneous materials, but probably originated from the denu-
dation of doleritic or diabasic rocks, and not as tuff or agglomerate.

2. Mineral Changes.

The rock-constituents afford evidence of many and various altera-
‘tions. These are especially illustrated in the numerous specimens
‘belonging to the doleritic or allied groups.

Felspar.—In nearly all cases the felspars are much changed, in some
completely so. Examples occur of the common dusty alteration, while
much of the felspar has developed flakes or films, either scattered or
massed together, of a minute mica-like mineral which may be some-
times a hydrous mica, sometimes kaolin. Epidote occurs in crystals,
or often as a granular aggregate; but some of the felspars are replaced
‘by zoisite or by a mixture of zoisite and epidote, and other groups of
these minerals probably are similarly derived. Occasionally a small
-amount of a greenish mineral resembling a serpentinous product is
present, and in one slide a quantity of chlorite is found within
-erystals which probably are felspar, a less usual alteration, and one
which is only possible by the interchange of constituents.?

Pyroxenic Minerals——In only one slide is there any ordinary
unchanged augite, and even there many of the crystals are either
partially or completely altered to an aggregate mostly of an actino-
litic character. Several of the rocks contain common, brown,
well-cleaved hornblende, nearly always exhibiting alteration to a
mottled and pale green or colourless variety or to actinolite. The
lustre-mottling of the crystals is interesting; they sometimes

1 See T. G. Bonney, ‘On some Schistose Greenstones, etc.,’ Quart. Journ. Geol.
Soe. vol. xlix. (1893) p. 103.
2c 2

372 . MISS C. A. RAISIN ON THE PETROLOGY [| Aug. 1897

include grains of felspar, sometimes probably a lime-pyroxene like
the picrite of St. David’s.! Apparently an added growth occurs in
one or two cases.” In several specimens an actinolitic aggregate is.
the only representative of the pyroxenic constituent, especially in
what seem to have been originally gabbros, although the diallage
structure is rarely recognizable in them. This actinolitic develop-
ment is not necessarily connected with any dynamo-metamorphism,
and may be considered to be probably an example of the second
class of alteration suggested by Prof. Bonney.? The rocks ex-
hibit other secondary minerals, the most interesting of which,
perhaps, is rutile, richly developed in one case within crystals-
idiomorphic in form, but-now consisting of an actinolitic aggregate,
like the development within serpeutine in certain altered peridotites.
where the outline of the originai olivine-grain is retained.* In
another rock, rutile apparently is formed from ilmenite, now replaced.
by leucoxene. In more than one case, mica has developed apparently
across structure-planes, as in the rocks described by Prof. Bonney.’

3. Pressure-effects.

The area described by Capt. Lyons as consisting of ‘ schistose”
rocks, and so marked on the accompanying map (Pl. XXVJ), is
illustrated in this collection by only five specimens. Judging from
these, the rocks all show effects of pressure, which in the probable:
phyllites are very strongly marked.

A crushed and brecciated vein-quartz is interesting as exhibiting
a separation of the quartz, and of the minute disseminated iron-oxide.
In this, however, as in so many other examples, doubtless the crushed
material facilitated the percolation of water, through the action of
which separation and recrystallization probably were caused. The
fragmental rocks have undergone pressure-modification, as in one
gritty limestone, and doubtless several of the basic rocks (altered.
gabbros and diabase), but these would offer much resistance and.
would not easily exhibit effects from this cause.

4. Meteorological Action.

One phenomenon of which there is clear evidence is the erosion
by wind and desert-sand, and the formation of a weathered coating.
The worn faces of the rocks usually are lumpy or irregular, but
with projections and depressions, smoothed or polished. ie many of
the crystalline rocks the pyroxenic constituent is slightly hollowed
out on the weathered surface, and apparently is the part first to
acquire the brown coating described by Walther and other observers.”
Whatever be the origin of this layer, the peculiar polish which .
accompanies it is almost certainly due to the wind-action noticed.
above.

+ T. G. Bonney, Quart. Journ. Geol. Soc. vol. xli. (1885) p. 519.

2 See also Whitman Cross, Am. Journ. Sci. ser. 3, vol. xxxix. (1890) p. 360.

3 Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 102.

4 Ibid. vol. liii. (1897) pp. 253, 262.

> ‘Lbid. vol. xlix..(1893) p. 104.

6 ‘Die Denudation in der Wiste,’ J. Walther, 1891, pp. 109-117.

Vol. 53.1 OF THE NUBIAN DESERT, 373

5. Relative Age of the Rocks, and Comparison with other
Localities.

While the coarse gneissic and granitoid rocks of the Nile Valley
mear Assuan are poorly represented, some likeness to those of a
more basic or intermediate type from Wadi Halfa is exhibited.’
‘The rocks which appeared to belong to an ancient series from that
part of the Nile Valley were, however, generally dioritic. The more
modified types in this collection from east of the Nile are usually
coarser, and are altered gabbro rather than diorite. Much of the
hornblende is similar to that in the less-altered diorites of the valley,
although in the latter the plagioclase is often somewhat fresher in
appearance. In one rock from the Second Cataract unchanged
augite occurred, as in No. 26 in this collection (p. 367).

The altered gabbros with remains of diallage, occasionally still
recognizable, rather resemble the well-known euphotide (Alpine
gabbro),” and this type has not been noticed, so far as I am aware,
from Upper Egypt. The almost pure hornblendite seems not to be
represented nearer than Pangani or Southern Abyssinia. The rarity
of these types in this southerly region can be seen by réferring to
the exhaustive list given by A. Rosiwal.* Notwithstanding specific
or varietal differences, however, the conclusions arrived at as regards
this area are similar to those suggested by examination of specimens
from parts of the Nile Valley; and even similar in the difficulty,
sometimes, of identifying with certainty all the members of the
ancient Archean series.*

It seems clear that the complex in this district east of the Nile
exhibits the old floor of crystalline rocks of which Capt. Lyons has
already noticed indications in the country west of the river (for
example, the gneiss of Jebel Abu Bayan). It is interesting to find
these basement-rocks exposed along what Capt. Lyons had suggested
may be an auticlinal axis.” The resemblances also to rocks which
have been described from near Wadi Halfa render this coincidence
the more striking, since it is by way of this locality that the
suggested anticlinal would cross the Nile Valley.

1 Geol. Mag. 1893, p. 487. Ihave to thank Mr. L. Fletcher, M.A., F.R.S.,
Keeper of Mineralogy at the British Museum of Natural History, for kindly
allowing me to re-examine the specimens described, as the rocks and slides have
been deposited in that collection.

2 « Petrological Notes on the Euphotide or Saussurite-smaragdite Gabbro of
the Saasthal,’ T. G. Bonney, Phil. Mag. ser. 5, vol. xxxiii. (1892) p. 287; ‘On
ssome Specimens of Gabbro from the Pennine Alps, T. G. Bonney, Min. Mag.
vol. ii. (1878) p. 5.

3 Denkschr. der Kais. Akad. der Wiss. Wien, vol. lviii. (1891): ‘ Beitr.
zur geol. Kenntniss des ostlichen Afrika,’ pt. ii. pp. 531-548.

4 Geol. Mag. 1893, p. 436.

° Quart. Journ. Geol. Soc. vol. 1. (1894) p. 539.

374. MISS E, ASTON: ANALYSES OF WATER — [Aug. 1897,

III. Warer ANALYsEs.
By Miss EK. Aszon, B.Sc.

The water was collected from wells in the Nubian Desert im
December 1894 by Capt. H.G. Lyons, R.E., who has sent with each
specimen the following description :—

1. Murrat Wells.

Water-surface 10 feet from the ground ; depth 2 feet 6 inches.. If
the water is all used up by a caravan, the well refills in a few hours,.
trickling in at thesides. Last fall of rain in November 1891, except
for two or three showers. No vegetation within half a mile of the
wells, which are sunk in the sand-and-gravel detritus filling the
valley. The supply of water is said by the Arabs to be unlimited.
Wells from 1 to 8 in number, open at various times.

2. Bir Tilat Abda.

Called by the Arabs a ‘bitter’ well. Water 20 feet from the:
surface ; well sunk in sand-and-gravel detritus. Considerable vege--
tation around it. Last rain in November 1891.

3. Bir Ab Araga.

Water 20 feet from the surface. A moderate number of trees and
shrubs in the vicinity. Last rain fell in November 1891.4, Used by
the Araps wno live in the neighbourhood.

The tables (p. 375) give the analyses of the waters. In the
first table the figures are the actual amounts of the substances
found; the second table gives the approximate constitution. The
wells are numbered as above:—1 = Murrat, 2 = Bir Tilat Abda,.
3 = Bir Ab Araga.

Quantities are tabulated in grains per gallon. The ‘total solid
matter’ was found by direct evaporation. The ammonia is expressed,.
in the usual manner, in parts per million.

PLATE XXVI,

Geological sketch-map of a portion of the Nubian Desert south-east
of Korosko, on the scale of 16 miles to 1 inch.

DIsctssIon.

Prof. Hurn was glad to find that Capt. Lyons was continuing
his geological observations up the Valley of the Nile. He presumed
that those described were the result of a reconnaissance made in
advance of the Geological Survey of Egypt, and they seemed to show
that the relations of the various formations above the First Cataract.
were similar to those about Assuan. The old Archean meta-
morphic rocks were found peering up through the nearly horizontal

.
\

Vol. 53-] FROM WELLS IN THE NUBIAN DESERT. 37
TaBLE I.
l

Welll. | Well 2. | Well 3. |
ALotal sod) matter? ...5...42. 410°5 359°5 95375
Be desiciadin ches Cans soumasiensaans Gust 2s 3°36 ; 2°48
HeKOret AMON MM tists ly auch, 0:26 4-36 0:96
Se ee) CPR, SAIL se 37°76 31°19 37°95
1 ean ee te _ Se 581 6-74 6:89
1G Ree Soe eee i 2: Ae Sa 61°38 63°88 21°91
TO Bt EOL See Caen” Tees eee aaa 32°08 30°41 11:18
Oe yg ost eae ead ov euse scene « trae 18252 142°47
Oe ECR Se ae as. ae eI 61:79 21:42 28°05
TO) eet set nn wa oc silted ates 1:86 1:88 trace.

377-45 | 34576 | 251-89
SE Sica OA, isc vote da eeibec te o's 0°378 0°105 0:199 .
Albuminoid ammonia ............ 0:185 0:173 0 260

Taste II.

Well 1. Well 2. Well 3.
By Nee ike aats wee seo ts ok 1:28 3°06 2°48
ENC ASSN Ces een OD 0:26 4:36 0:96
AT Sa oh ys «i ck ay 8S 34:18 1073 1°45
125 G1 Fol soe md LER, ba a 1581 41°71 17:29
LS) CSA ee eam oer. Serie eis rae 170°25 146°49 46°45
VCC a ie ne Hea 21-27 au aa
‘TESTE SAR ae Aye oe on 28-15 32-65 33:35
KN CO Pad eawaci sec naecanupigeanates 3:03 3:06 2:26
CASO Aci cs dias dca oman semen 59°50 81°87 120:13
CaCO. —) 2 : “5
HCO: } ee he ee 82-04 28°79 10°56

415°77 35302 23493

376 GEOLOGY OF THE NUBIAN DESERT. fAug. 1897,

beds of the Nubian Sandstone—probably along the axes of low
saddles—and throwing off the stratified deposits on all sides. He
noticed the suggestion that possibly there were two divisions of the
Nubian beds—namely, the conglomerates and varied strata in the
lower part, and the more solid sandstones in the upper (from which
the building-stones of the great temples had been derived); but the
question whether all these deposits were merely variations of one
great lacustrine (or estuarine) formation, or were distinct formations,
could be determined only by a detailed survey. Regarding the
igneous rocks which occur as dykes traversing the old rocks, it was
clear that they belong to some period intermediate between the
Archean and the Cretaceous—possibly Upper Paleozoic. He
thought that when the waters of the old wells became saturated
with salts, the best plan would be to sink new wells close by
in favourable positions, in which the waters would probably be
found less saline.

The Rey. J. F. Braxe thought that geologists seemed rather too
ready to suppose comparatively recent changes of climate to account
for phenomena which they could not otherwise explain. In the
present case the depressions in the river-beds called ‘ potholes’ are
thus accounted for. In Cutch, however, there were numerous
similar depressions filled with water all the year round, while the
remainder of the stream-course was dry sand, and yet there was
evidence that the general conditions of climate had been constant
for along time. It was possible, therefore, that in the case of the
district described a varying intensity of rainfall, or the diversion of
the water falling on higher reaches of the streams into other
courses, owing to physical changes beyond the district in question,
might account for the present lack of water, without any very
serious alteration of the climatic conditions,

Prof. Bonney said that it had occurred to him that possibly the
lower conglomerate mentioned by Capt. Lyons might be pre-
Cretaceous, like those described by Prof. Hull. He did not think
that much good would come from sinking fresh wells. As regards
the origin of the wadis and rounded stones, he did not see how
these phenomena could possibly be explained without a heavier
rainfall, and that climate had changed was a geological common-
place. He thought that the wells were in detritus.

Quart. Journ. Geol. Soc. Vol. LITT. Pl. XXVI.

33° oe: 33°30! 34°

32°30’

SKETCH- MAP
of a portion of the

NUBIAN DESERT

SOUTH-EAST OF

KOROSKO

Scale: 16 miles=1 inch

-_ Cs ~ 9

cS)
oe 3
meer se =
=
; '
| &
‘ Me 3
‘aad “a | S §
J
s x
é man Ee)
ieee “JEBEL winnie 8
te KHaTAB Wo cine Q

qa «, SEL ARRIAN Cite

: sh Sa » AKABA ABU TUNDUL
40 Jorn a a= -
yates .
e Tr
NAsB HAMUDA3< 5
sae oo Mioe a Deehe Dati TW IAbAraga ele

Quart. Journ. Geol. Soc. Vol. LIT. Pl. XXVI.

SKETCH- MAP
of a portion of the

NUBIAN DESERT

SOUTH-EAST OF

KOROSKO

———
Scale: 16 miles=1 inch

per

~ 1,012,760

EXPLANATION.
Tubsan Sandstone.
ih, Crystalline Schists &c.
ES] Avassive Crystalline Rocks.

Jebel — Hill
Tilat — Ravine
Wadi= Valley
Bir....— Well
~------ = Caravan Routes

Gepet ABU KARAN

HAGAR GHAWAB

PAS,

Kuet EL GHUz

J. HAGAR aM,
EL ZARGA’

+s; MAGDUD BL
ORY

“JEBEL
AKHATAB

SEL ARRIAN bi Me
é » AKABA ABU TUNDUL

pooy 4299489 — anulyp}}~<—-------

—*\ sy. ABU HAD
rs

4%,
1

Uf

JEBEL OM DECANE, of
13

‘Ty,

4%

wi,
Mos Kenar

Wadi Hal: ay ; hs €
oe J BIRAT

Stor TT
Avert tt

Sey
De
|

yz
Pes

ie
wa,

33° E. of Greenwich

Vol. 53.] THE MOLLUSCA OF THE CHALK ROCK. 377

28..,The Moxivsca of the Cuatk Rock: ParrIl. By Henry Woops,
M.A., F.G.S. (Read May 12th, 1897.)

[Puates XXVII. & XXVIIT.]

ConTENTs.
Page
Me MTGE OG UCCLOI 5 9 snus xguges nema sie cameras oe a hele aicieiat= sistee sarornsi telat 377
Cranial eAR CMA, (Lia. nis cpte cans naaanses ted ater wcodure x @tGs smenrds vars bias 377
Nuculana. Ostrea, Cardita.
Nucula, Chiamys. Arctica,
Arca. Tima. Trapezium.
Limopsis. Spondylus. Corbis ?
Modiola. Plicatula. Martesia?
Inoceramus. Cardiuwm. Cuspidaria.
III. Table of Distribution of the Lamellibranchia ............ facing 394
IV. Distribution and Relations of the Fauna .................ssseeeeeee 394
V. Conditions under which the Chalk Rock was Deposited......... 398

I. InrrRopvuction.

‘Tue first part of this paper, dealing with the Cephalopoda, Gastero-
poda, and Scaphopoda, appeared in the preceding volume of this
Journal.’ In the present communication I propose to consider the
Lamellibranchia, and to discuss the relations and distribution of the
fauna of the Chalk Rock and the conditions under which that fauna
lived.

The Lamellibranchs are represented by a larger number of species
than either the Cephalopoda or the Gasteropoda, but, on account of
the imperfect manner in which their remains are preserved, greater
difficulty has been found in studying them than was the case with
the groups considered in Part I. Again, there is evidence of the
existence of forms other than those herein described, but the speci-
mens now at my disposal are not sufficiently good for determination.
I shall hope, after more collecting has been done, to be able to
supplement this work, and shall be grateful for any opportunity of
examining specimens from this zone.

For further assistance I must again thank the gentlemen men-
tioned in Part I., particularly Mr. Jukes-Browne, Mr. E. T. Newton,
Mr. G. C. Crick, and Mr. R. M. Brydone.

II. Class LAMELLIBRANCHIA.
Family Nuculanide, Stoliczka.
Genus Noucurana, Link, 1807
[ = Leda, Schumacher, 1817].

Nocuzana cf. srrieva (Goldfuss).
1837. Nucula siliqua, A. Goldfuss, ‘ Petref. Germ.’ vol. ii. p. 156, pl. exxv. f. 13;
1846. A. E. Reuss, ‘Die Verstein. der béhm. Kreideformat.’ pt. ii. p. 7, pl. xxxiv.

1 Vol. lii. (1896) pp. 68-98 & pls. ii-iv. Correction to be noted there :—
pp. 88 et segg., for Trochus berocscirense read Trochus berocscirensts,

378 MR. H. WOODS ON THE MOLLUSCA [Aug. 1897,

f. 11; 1889. O. Griepenkerl, ‘Die Verstein. der Senon. Kreide von Kénigslutter,’
Palaont. Abhandl. vol. iv. p. 57.

1850. Leda siliqua, A.d’Orbigny, ‘ Prodr. de Pal.’ vol. ii. p. 236; 1877. A. Fritsch,
‘Stud. im Gebiete der bohm. Kreideformat. II. Die Weissenberger u. Malnitzer
Schichten,’ p. 117, f. 81; 1889. E. Holzapfel, ‘Die Mollusken der Aachener Kreide,’
Paleontographica, vol. xxxv. p. 203; 1893. A. Fritsch, ‘Stud. im Gebiete der bohm.
ea. V. Priesener Schichten,’ p. 92 ; 1895. F. Vogel, ‘ Die holland. Kreide,’
p. 37.

1885. Nuculana siliqua, F. Notling, ‘Die Faunad. baltisch. Cenoman-Geschiebe,’
Palaont. Abhandl. vol. ii. pt. iv. p. 27, pl. iv. f. 15.

[Non Nucula siliqua, H. B. Geinitz, ‘Char. d. Schichten u. Petref. d. sachs.-
bohm. Kreidegeb.’ pt. ii. (1842) p. 77, pl. xx. f. 28 & 29.]

Remarks.—There are two specimens in the Montagu Smith
Collection which agree well with the figures given by Goldfuss and
Reuss, but since, like the figured specimens, they are in the form of
casts, it is difficult to be sure of their identity. The approximate
size of one of the specimens is:—length=16 mm. ; height=6 mm.
The type of the species comes from the Aachen Greensand (Lower
Senonian).

Distribution.—England: Chalk Rock of Cuckhamsley. North-
western Germany: Maestrichtian of Konrath near Aachen; Hervien
of Aachen. Bohemia: Weissenberg and Priesen Beds.

Family Nuculide, Gray.
Genus Nucuta, Lamarck, 1799.

Nucura sp. (Pl. XXVILI. figs. 1 & 2.)

Remarks.—A. species of Nucula is represented in the Montagu
Smith Collection by eleven specimens ; it approaches closely in form
@’Orbigny’s V. Renauaiana' found in the Turonian of Uchaux, but,
unfortunately, all the specimens are internal casts, so that an exact
determination is impossible. Size of an average specimen: length
=13 mm.; height=10 mm.

Distribution.—Chalk Rock of Cuckhamsley.

Family Arcide, Lamarck.
Genus Arca, Linnzeus, 1766.

Arca sp., cf. GALLIENNEI, d’Orbigny. (Pl. XXVII. fig. 3.)

There are two casts from Cuckhamsley in the Montagu Smith
Collection which agree with A. Gallhiennei, dOrbigny,’ from the
Cenomanian of Le Mans, Rouen, etc., except that they are rather
shorter. Size of a specimen: length=33 mm.; height=19 mm.

Arca (BarzatiA) sp., cf. Gernitzr, Reuss, 1844. (Pl. XXYVII.
figs. 5 & 6.)

[See especially, Reuss, ‘ Geogn. Skizzen,’ vol. ii. (1844) p. 192, and ‘ Die Verstein.
der béhm. Kreideformat.’ pt. ii. (1846) p. 11, pl. xxxiv. f. 31; Geinitz, ‘ Das

1 «Pal. Franc. Terr. Crét.’ vol. iii. (1843-47) p. 179 & pl. ecciv. figs. 7-9. This
is regarded by Pictet & Campiche, ‘ Foss. Terr. Crét. Ste. Croix,’ pt. iii. (1866)
p. 418, as a synonym of JV. zmpressa, Sowerby.

2 Op. supra cit. p. 218 & pl. ecexiv.

mM

Vol. 53.] OF THE CHALK ROCK. 379

Elbthalgeb. in Sachsen,’ pt. ii. (1873) p. 55, pl. xvi. f. 78; Fritsch, ‘Stud. im
Gebiete der bohm. Kreideformat. IV. Die Teplitzer Schichten ’ (1889), p. 79, fig. 63 ;.
Favre, ‘ Moll. Foss. de la Craie des Envir. de Lemberg’ (1869), p. 125, pl. xii.
f.15 & 16.]

Remarks.—A specimen, consisting of an internal, and part of an
external mould, agrees with A. Gewnitz, in form, but differs in
possessing rather finer and more numerous ribs. It is probably the.
form figured by Sowerby as Byssoarca marullensis' from the Chalk
of Kent. Size of specimen from Cuckhamsley: length (approxi-
mate)=23 mm.; height=11 mm.

A, Geinitzi occurs in the Planer-Kalk of Strehlen (Saxony), in
the Teplitz Beds of Bohemia, etc.

Distribution.—Chalk Rock of Cuckhamsley.

Arca sp. (Pl. XXVII. fig. 4.)

Description.—Shell oblique, elongate, anteriorly very short and
rounded. Posterior margin oblique, somewhat rounded. Umbones
sharp. Surface with concentric lines of growth; and with radiat-
ing ribs extending from the umbo to the posterior margin. Size:
length=13 mm.; height=6 mm.

Remarks.—This species is at present known by one specimen
only. It resembles Arca strehlensis, Geinitz, from the Pliner-Kalk
of Strehlen, but in that form the shell is less oblique, and the
surface is generally smooth, except on the anterior part which is
marked with radiating ribs.

Distribution.—Chalk Rock of Cuckhamsley (Montagu Smith
Collection).

Genus Limopsis, Sassi, 1827.

Limorsis sp. (Pl. XXVII. figs. 7 &.8.)

Description.—Shell small, oval, convex, a little oblique, wider
than long ; margins of valves not crenulate. Casts show fine radi-
ating striz, sometimes crossed by a few shallow concentric furrows.
Size: length=8 mm., height=7 mm.

Remarks.—At present this species is known only from the casts,
so that a complete description cannot yet be given; it seems, how-
ever, quite distinct from the other forms. I have not been able to
make out the hinge-plate in a satisfactory manner, and it is possible:
that this species may really belong to Avinwa.

Affinities—Romer’s* Pectunculus planus is similar to this species,.
but the valves are flatter and the umbones less prominent.

Distribution.—Chalk Rock of Cuckhamsley.

* Sowerby (non d’Orbigny) in F. Dixon’s ‘ Geol. Sussex’ (1850), p. 355 &
Me xxviii. fig. 11. I have not been able to find the original of Sowerby’s
gure. ,
* ‘Die Verstein. des norddeutsch. Kreidegeb.’ 1841, p. 69 & pl. viii. fig. 24.

380 ‘MR. H. WOODS ON THE MOLLUSCA [Aug. 1897,

Family Mytilide, Lamarck.
Genus Moprora, Lamarck, 1799.

Moprota Corrm, Romer, 1841. (Pl. X XVII. figs. 9-12.)

1840. Modiola Cotte, H. B. Geinitz, “Char. der Schicht. u. Petref. des sachs.
Kreidegeb.’ pt. ii. p. 56, pl. x. f. 5; 1873. H. B. Geinitz, ‘Das Elbthalgebirge in
Sachsen,’ Palzontographica, vol, xx. pt. 1. pl. xlvui. f. 4-8, p. 214.

1841. "Mytilus Cotte, F. A. Romer, ‘ Die Verstein. des norddeutsch. Kreidegeb.’
p- 66, pl. vin. f. 18; 1843. H. B. Geinitz, ‘ Die Verstein. von Kieslingswalda,’ p. 15;
1846. A. E. Reuss, ‘ Die Verstein. der bohm. Kreideformat.’ pt. ii. p. 14, pl. xxxiii.
f. 4; 1850. A. d’Orbigny, ‘ Prodr. de Pal.’ vol. 11. p. 246; 1889. A. Fritsch, ‘Stud. im
Geb. der bohm. Kreidetormat. IV. Die Teplitzer Schichten,’ p. 79, f. 66.

1842. ? Mytilus Cuvieri, P. Matheron, ‘ Cat. méth. et descript. des Corps org. foss.
du Dép. des Bouches-du-Rhéne,’ p. 179, pl. xxviii. f. 9 & 10.

1850. Modiola quadrata, J. de C. Sowerby, in F. Dixon’s ‘ Geol. Sussex,’ p. 347,
pl. xxvii. f. 13 [p. 382, 2nd ed.]; 1854. J. Morris, ‘ Cat. Brit. Foss.’ 2nd ed. p. 211.

Remarks.—This species was figured by J. de C. Sowerby as
Modiola quadrata; but I have not been able to find the type,
which was stated to come from the Lower Chalk, no locality being
mentioned. The figures of JM. Cotte given by different authors
vary considerably, but a careful comparison of the Chalk Rock
specimens with the figures in Geinitz (‘Das Elbthalgebirge in
Sachsen ’) and Fritsch leaves practically no doubt that M. quadrata
is identical with W. Cotte. The type of the latter comes from the
Cenomanian of Plauen, near Dresden. In England the species is
not common.

Distribution.— England : Chalk Rock of Winchester, Cuckhamsley,
Luton cutting, and Underwood Hall near Dullingham. Upper
Chalk of Northfleet. Sawony: Cenomanian Pliner of Plauen;
Lower Quader Sandstone (Cenomanian) of Golberoda, and Klein-
Nauendorf; Pliner-Kalk of Strehlen. Bohemia: Teplitz Beds.

Family Pernide, Zittel.
Genus Inocrramus, Sowerby, 1819.

Tyoczramus Broneniarti, Sowerby, 1823.

1823. Inoceramus Brongniarti, J. de C. Sowerby, ‘Min. Conch.’ vol. v. pl. cccexli.
f.2 & 3, p. 60; 1854. J. Morris, ‘Cat. Brit. Foss.’ 2nd ed. p. 169.

[Non I. Brongniarti, G. A. Mantell, ‘ Foss. 8. Downs’ (1822), p. 214, pl. xxvii. f. 8.]

1822. Inoceramus Lamarcki, G. A. Mantell (non Parkinson), ‘ Foss. S. Downs,’
p. 214, pl. xxvii. f. 1.

Remarks.—In the present paper I shall refrain from giving a
full account of the synonymy and distribution of the species of
Inoceramus which occur in the Chalk Rock, as I hope to deal at
another time with all the species of this genus. The specimen
figured by Mantell is different from Parkinson’s species, and is
probably identical with Sowerby’s Brongniarti. Mantell’s Bron-
gniarti appears to be the same as Parkinson’s. Sowerby’s types
(without locality) are preserved in the British Museum, and also
the originals of Mantell’s J. Lamarcki, from near Lewes, and of his
Brongniarte from Sussex.

Distribution.—England : Chalk Rock of Cuckhamsley, Old-
borough Castle, and Luton. Upper Chalk.

Vol. 53.]- OF THE CHALK ROCK. 381

InoceraMus striatus, Mantell, 1822. (Pl. XXVILI. fig. 13.)

1822. Inoceramus striatus, G. A. Mantell, ‘ Foss. S. Downs,’ p. 217, pl. xxvii. f.5;
1828. J. de C. Sowerby, ‘ Min. Conch.’ vol. vi. p. 160, pl. dlxxii. f 2; 1854. J. Morris,
‘Cat. Brit. Foss.’ 2nd ed. p. 170; 1872-73. H. B. Geinitz, « Das Elbthalgeb. in Sachsen,’
Paleontographica, vol. xx. pt. 1. p. 210, pl. xlvi. f. 9-13; pt. ii. p. 41 (?? pl. xiii. f. i,
2, 9, 10).

Remarks.—The specimens found in the Chalk Rock differ from
the types in being less rounded—they are higher than long. If
this character be constant it may indicate a different species, but
this cannot be determined until a much larger collection has been
obtained. At present I have seen only three or four specimens from
the Chalk Rock; they agree in form with some which were col-
lected from the Upper Chalk of Newmarket. Size of Chalk Rock
specimens :—(1) Length=24 mm.; height=33 mm. (2) Length
=30 mm.; height=38 mm.

Both Mantell’s and Sowerby’s types are in the British Museum;
the former was obtained at South Street, Lewes; the latter near
Heytesbury (? Lower or Middle Chalk).

Distribution.—England : Chalk Rock of Roman Road (south-east
of Calstone Willington) and Cuckhamsley. Lower, and perhaps
also Middle and Upper, Chalk. Ireland: Hibernian Greensand—
Chloritic Sandstone division ( fide Tate).

Inoceramus sp. (Pl. XXVILI. figs. 14-17.)

Remarks.—A small species, which is unlike any described form
with which I am acquainted, but is at present represented by casts
only, is moderately common in the Chalk Rock. The shell is rather
convex, higher than long, with shallow concentric furrows and
prominent pointed umbones.

Distribution —Chalk Rock of Lichfield (Hants), Winchester,
Roman Road south-east of Calstone Willington, Cuckhamsley,
Luton cutting, Wallington near Baldock, and Underwood Hall
near Dullingham.

Family Ostreidee.
Genus Osrrua, Linneus, 1766.

OsTREA SEMIPLANA ?, Sowerby, 1825.

1825. Ostrea semiplana, J. de C. Sowerby, ‘ Min. Conch.’ vol. v. pl. ecccelxxxix. f. 3,
p. 144.

Remarks.—The genus Ostrea is poorly represented in the Chalk
Rock. The specimens which I believe to be referable to O. semi-
plana are rather small, and this probably accounts for the fact that
the plications of the marginal part of the valves are only faintly
indicated. Sowerby’s types came from Norwich, and are now in the
British Museum.

Distribution.—England: Upper and Middle Chalk ; Chalk Rock
of Cuckhamsley, and Underwood Hall near Dullingham. Ireland:
Hibernian Greensand. Northern France: zone of 7. gracilis in the
Yonne and Aube, zone of Hpiaster brevis at Thiernu, zone of J. brev2-
porus at Cambrai, Senonian of the neighbourhood of Epernay and

382 MR. H. WOODS ON THE MOLLUSCA (Aug. 1897,

Reims. Aachen: Quadrata- and Mucronata-beds. North-western
Germany : Senonian of Salzberg, Ceesfeld, etc. Saxony : Cenomanian
of Plauen, Planer-Kalk of Strehlen and Weinbohla. Silesia:
Cenomanian of Bladen. Bohemia: Weissenberg, Malnitz, Iser,
Teplitz, and Priesen Beds. Bavaria: Kagerhoh Beds. Galicia: Chalk
of Nagorzany and Lemberg.

Family Pectinide, Lamarck.
Genus Cutamys, Bolten, 1798.

Cuiamys TERNATA (Goldfuss), 1833.

1833. Pecten ternatus, A. Goldfuss, ‘ Petref. Germ.’ vol. 1. p. 52, pl. xci. f. 13;
1841. F. A. Romer, ‘ Die Verstein. des norddeutsch. Kreidegeb.’ p. 53; 1842. H. B.
Geinitz, ‘Char. d. Schichten u. Petref. des saichs.-bdhm. Kreidegeb.’ pt. iii. p. 83;
1850. A. d’Orbigny, Prodr. de Pal. vol. ii. p. 252 ; 1889. O. Griepenkerl, ‘ Die Verstein.
der Senon. Kreide von K6nigslutter,’ Palaont. Abhandl. vol. iv. p. 43.

1837. Pecten septemplicatus, F. Dujardin (non Nilsson), Mém. Soc. géol. France,
vol. il. p. 227, pl. xvi. f. 11.

1841. Pecten Dujardini, F. A. Romer, ‘ Die Verstein. des norddeutsch. Kreidegeb.’
p. 53; 1843-47. A. d’Orbigny, ‘ Pal. Frang. Terr. Crét.’ vol. 11. p. 615, pl. cccexxxix.
f. 5-11; 1846 Pp? A. E. Reuss, ‘Die Verstein. der bohm. Kreideformat.’ pt. ii. p. 30,
pl. xxxix. f.17 ; 1850. J. de C. Sowerby, in F. Dixon’s ‘ Geol. Sussex,’ p. 356, pl. xxviii.
f. 4; 1850. A. d’Orbigny, ‘ Prodr. de Pal.’ vol. 11. p. 251; 1850. H. B. Geinitz, ‘ Das
Quadersandsteingeb. oder Kreidegeb. in Deutschland,’ p. 184; 1854. J. Morris, ‘ Cat.
Brit. Foss.’ 2nd ed. p. 176; 1870. F. Romer, ‘ Geol. von Oberschlesien, p. 340, pl. xxix.
f. 2, pl. xxxvii. f.5; 1870. F. J. Pictet & G. Campiche, ‘ Foss. du Terr. Crét. de Ste.
Croix,’ Matér. Pal. Suisse, ser.5, pt. iv. p.219 ; 1872. H. B. Geinitz, ‘ Das Elbthalgeb.
in Sachsen,’ Paleontographica, vol. xx. pt. 11. p. 36, pl. x. f. 10-12; 1877. A. Fritsch,
“Stud. im Gebiete der bohm. Kreideformat. II. Die Weissenberg. u. Malnitzer
Schichten,’ p. 136, f. 137; 1883. A. Fritsch, ‘Stud. im Gebiete der bohm. Kreide-
format. III. Die Iserschichten,’ p. 116; 1889. Fritsch, ibid. IV. ‘Die Teplitzer
Schichten,’ p. 85; 1893. Fritsch, ib¢d. V. ‘Die Priesener Schichten,’ p. 100 ; 1893.
R. Michael, Zeitschr. d. Deutsch. geol. Gesellsch. vol. xlv. p. 242.

1842. ? Pecten squamifer, H. B. Geinitz, ‘ Char. d. Schichten u. Petref. des sachs.-
bohm. Kreidegeb.’ pt. ii1. p. 83, pl. xxi. f. 5; 1850 ? Geinitz, ‘Das Quadersandstein-
geb. oder Kreidegeb. in Deutschland,’ p. 184.

Remarks.—I have seen only two specimens of this form from the
Chalk Rock. The species was founded by Goldfuss on a cast from
the Quader Sandstone of Schandau. A specimen from Touraine
was described by Dujardin as P. septemplicatus, Nilsson, but it was
shown to be distinct from that species by Rémer, who changed the
name to P. Dwjardini, by which it has since been generally known.
Geinitz’s P. squamifer and Reuss’s P. Dujardini appear to be
distinct from this species.

Distribution.—England: Chalk Rock of Winchester, and Clothall
near Baldock. Upper Chalk of Sussex (fide Morris). France: zone
of Micraster breviporus at Cambrai, zone of Epiaster brevis east of
the Paris basin, zones of Spondylus truncatus and Sp. spinosus in
Loir-et-Cher, zone of J:ccraster cor-testudinarium in the Nord, Upper
Chalk of Tours (Indre-et-Loire). Sawvony: Middle Quader Sand-
stone (Inoceramus labiatus-beds) of Rottwernsdorf and Gross-Cotta,
Upper Pliner of Kritzschwitz near Pirna, Glauconitic Sandstone
(Brongniarti-beds), and Planer-Kalk of Strehlen and Weinbohla.
Silesia : Scaphites-beds of Oppeln. Bohemia: Weissenberg, Mal-
nitz, Iser, Teplitz, and Priesen Beds. Bavaria: Kagerhoh Beds.

Mol. 53:| OF THE CHALK ROCK. 383

Family Limide, d’Orbigny.
Genus Lima, Chemnitz, 1784.

Lima GRANOSA, Sowerby, 1850.

1850. Lima granosa, J. de C. Sowerby in F. Dixon’s ‘Geol. Sussex,’ p. 347,
pl. xxviii. ff. 24 & 25 [p. 382, 2nd ed.] ; 1854. J. Morris, ‘ Cat. Brit. Foss.’ 2nd ed. p.171.

Remarks.—Sowerby does not state from what locality his speci-
mens came, and I have not been able to find the type. I have seen
only two examples from the Chalk Rock.

Distribution.—England : Chalk Rock of Winchester (coll, R. M,
Brydone). Chalk of Sussex. Upper Chalk of Norwich.

Subgenus Praciostoma, Sowerby, 1812.

Lima (Praciostoma) Horrr1, Mantell, 1822.

1822. Plagiostoma Hoperi, G. A. Mantell, ‘Foss. 8. Downs,’ p. 204, pl. xxvi.
f. 2, 3,15; 1822. J. Sowerby, ‘Min. Conch.’ vol. iv. p. 111, pl. ccclxxx; 1850. var.,

J.de C. Sowerby in F. Dixon’s ‘ Geol. Sussex,’ p. 345, pl. xxvu. f. 21 (p. 383, 2nd ed.).

1822. Plagiostoma Mantelli, A. Brongniart, ‘ Descr. géol. des Environs de Paris,’
p. 600, pl. iv. f. 3; 1839. H. B. Geinitz, ‘Char. d. Schichten u. Petref. des
sachs. Kreidegeb.’ p. 24.

1836. Lima Mantelli, A. Goldfuss, ‘ Petref. Germ.’ vol. ii. p. 92, pl. civ. f. 9;
1841. F. A. Romer, ‘Die Verstein. des norddeutsch. Kreidegeb.’ p. 58; 1846. H. B.
Geinitz, ‘Grundriss der Verstein.’ p. 472, pl. xx. fig. 13; 1847. R. Kner, ‘ Verstein.
des Kreidemerg. v. Lemberg,’ Haidinger’s Naturwiss. Abhandl. vol. iii. pt. ii. p. 29.
1877 2 A. Fritsch, ‘Stud. im Gebiete der bohm. Kreideformat. II. Die Weissenb. u.
Malnitzer Schichten,’ p. 134, f. 122.

1825. Pachytos Hoperi, Defrance, ‘ Dict. des Sci. naturelles,’ vol. xxxvii. p. 207.

1827. Plagiostoma punctatwm, 8. Nilsson, ‘Petref. Suecana,’ p. 24, pl. ix. f. 1;
1837. W. Hisinger, ‘ Lethza Suecica,’ p. 54, pl. xv. f. 3.

1830. Lima Hoperi, G. P. Deshayes, ‘ Encycl. méth., Hist. nat. des Vers,’ vol. ii.
p. 349; 1836. A. Goldfuss, ‘ Petref. Germ.’ vol. ii. p. 91, pl. civ. f. 8; 1836. G. P.
Deshayes & H. Milne-Edwards, ‘ Hist. nat. des Animaux sans Vert.’ (Lamarck,
2nd ed.) vol. vii. p. 120; 1838. H. G. Bronn, ‘ Lethea Geogn.’ 2nd ed. vol. ii. p. 682,
pl. xxxii. f. 8; 1839. H. B. Geinitz, ‘Char. der Schicht. u. Petref. des sachs.
Kreidegeb.’ p. 24; 1841. F. A. Romer, ‘ Die Verstein. des norddeutsch. Kreidegeb.’
p. 58; 1846. H. B. Geinitz, ‘Grundriss der Verstein.’ p. 473, pl. xx. f. 14; 1846.
A. E. Reuss, ‘Die Verstein. der bohm. Kreideformat.’ pt. 11. p. 34, pl. xxxviii,
f. 11 (212); 1850. A. Alth, ‘Geogn.-pal. Beschreib. der nachst. Umgeb. von
Lemberg,’ Haidinger’s Naturwiss. Abhandl. vol. i. pt. ii. p. 240; 1850. H. B.
‘Geinitz, ‘Das Quaderstandst. oder Kreidegeb. in Deutschland,’ p. 192; 1854. J.
Morris, ‘Cat. Brit. Foss.’ 2nd ed. p. 171; 1863. A. v. Strombeck, Zeitschr. d. Deutsch.
geol. Gesellsch. vol. xv. p. 148; 1863. R. Drescher, zbid. vol. xv. p. 355; 1869.
EE. Favre, ‘ Descr. des Moll. Foss. de la Craie des Envir. de Lemberg,’ p. 137, pl. xii.
f.19; 1870. F. Romer, ‘Geol. von Oberschles.’ p. 315, pl. xxxiv. f. 10; 1870. F. J.
Pictet & G. Campiche, ‘ Foss. du Terr. Crét. de Ste. Croix,’ ser. 5, pt. iv. Matér.
Paléont. Suisse, pp. 171, 173; 1872. H. B. Geinitz, ‘Das Elbthalgeb. in Sachsen,’
Palzontographica, vol. xx. pt. i. p. 40, pl. ix. f. 11 & 12; 1877. A. Fritsch, ‘Stud. im
Gebiete der bohm. Kreideformat. II. Die Weissenb. u. Malnitzer Schichten,’
p. 134, f. 121; 1882. H. Schroder, Zeitschr. d. Deutsch. geol. Gesellsch. vol. xxxiv.
p- 263; 1887. A. Peron, ‘Notes pour servir 4 ]’Hist. du Terr. de Craie,’ Bull. Soc.
des Sci. hist. et nat. de l’Yonne, ser. 3, vol. xu. p. 149; 1889. E. Holzapfel, ‘ Die
Mollusken der Aachen. Kreide,’ Paleontographica, vol. xxxv. p. 240, pl. xxvii. f. 5;
1889. A. Fritsch, ‘Stud. im Gebiete der bohm. Kreideformat. IV. Die Teplitzer
Schichten,’ p. 84, f. 78; 1893. A. Fritsch, ibid. V. ‘ Die Priesener Schichten,’ p. 100 ;
1895. B. Lundgren, ‘Molluskfaunan i Mammillatus- och Mucronata-zonerna i
nordéstra Skane,’ K. Svenska Vet.-Akad. Handl. n. f. xxvi. no. 6, p. 62. { Non 1843-
47. Lima Hoperi, A. d’Orbigny, ‘ Pal. Frang. Terr. Crét.’ vol. iii. p.564, pl. cccexxiv.
f. 10-13.

1893. eee sp., cf. Hoperi, R. Michael, Zeitschr. d. Deutsch. geol. Gesellsch.
vol, xlv. p. 234.

384 ‘MR. H. WOODS ON THE MOLLUSCA [Aug. 1897,

1850. Lima Sowerbyi, H. B. Geinitz, ‘Das Quadersandst. oder Kreidegeb. im
Deutschland,’ p. 192; 1851. J. Miller, ‘Mon. der Petretact. der Aachener Kreide-
format.’ pt. il. p. 67; 1851-52. H. G. Bronn, ‘ Lethea Geogn.’ 3rd ed. vol. ii. p. 278,
pl. xxxii. f. 8; 1870. F. J. Pictet & G. Campiche, ‘ Foss. du Terr. Crét. de Ste. Croix,”
ser. 5, pt. iv., Matér. Paléont. Suisse, p. 173; 1872. H. B. Geinitz, ‘Das Elbthalgeb..
in Sachsen,’ Palzontographica, vol. xx. pt. 11. p. 41, pl. ix. f.13 & 14; 1883. A. Fritsch,
‘Stud. im Gebiete der bohm. Kreideformat. III. Die Iserschichten,’ p. 115, f. 87.

a Lima Nilssoni, F. A. Romer ‘ Die Verstein. des norddeutsch. Kreidegeb.”

One
: 1842. Lima Goldfussi, ¥. v. Hagenow, Leonhard’s Neues Jahrb. p. 555.

1892. Lima (Plagiostoma) Hoperi, K. Stolley, ‘ Die Kreide Schleswig-Holsteins,”
Mitth. aus dem Min. Inst. Univ. Kiel, vol. i. p. 237; 1888. O. Griepenkerl, ‘ Die-
Verstein. der Senon. Kreide von Kénigslutter,’ Palaont. Abhandl. vol. iv. p. 40.

Remarks.—The ornamentation varies considerably in this species.
In some examples the shell is almost smooth, except near the anterior
and posterior margins ; in others the whole surface is marked with
pitted grooves, which, however, are usually less distinct near the
centre than on the anterior and posterior parts of the shell. There
is every gradation between these two extremes; in some cases the
differences are due to imperfect preservation. Some specimens
show the ornamentation near the umbo, but not on the rest of the
shell.

Geinitz considers that Sowerby’s ZL. Hoperi is distinct from
Mantell’s ; the former (which he names L. Sowerby) is for the
most part smooth; the latter possesses grooves over the whole
surface. These differences, as I have pointed out above, are not of
specific value; there can be no doubt whatever that Mantell’s
fig. 2 is the same species as Sowerby’s, and moreover Sowerby
received his specimens from Mantell. The examples figured by
both authors came from Lewes: Sowerby’s specimens are in the
British Museum, but I have not seen Mantell’s.

The species described by Brongniart as Plagiostoma Mantelli
was considered by Mantell* to be identical with L. Hoperi.

Different specimens of LZ. Hopert show a considerable amount of
variation in the relative proportions of the length and height, some
being higher than long, others longer than high.

Distribution.—England : Chalk Rock and Upper Chalk—not
common in the former. Chalk Rock of Luton cutting, Westley
Waterless, and Underwood Hall near Dullingham. Jreland: White
Limestone. Srance: zone of Micraster breviporus at Cambrai ;
zone of Epiaster brevis at St. Clément and Guise; zone of M. cor-
anguinum at Banogne and Lezennes. Belgium: Senonian of
Limbourg. Aachen: Mucronata-beds of Vaals and Henry-Chapelle.
Westphaha: Senonian of Cosfeld; Mucronata-beds of Haldem,
etc.; Quadrata-beds of Ilsenburg ; Scaphites-beds of Quedlinburg ;
and Inoceramus Brongniarti-Planer. Brunswick: Upper Senonian
of Konigslutter. Sawvony: Pliner-Kalk of Strehlen and Weinbohla.
Silesia: Scaphites-beds of Oppeln. Schleswig-Holsten: Quadrata-
beds of Ligerdorf. Bohemia: Weissenberg, Malnitz, Teplitz, and
Priesen Beds. Bavaria: Grossberg Beds. Galicia: Chalk of
Nagorzany (Lemberg). Scania: Mammallatus-zone of Ignaberga,

etc.
1 Trans. Geol. Soc, ser. 2, vol. iii. (1835) p. 206.

Vol: 53. | OF THE CHALK ROCK. 389

Sabgenus Acesta, Adams, 1855.

Lia (Acesta ?) supaBrupta, d’Orbigny, 1850.

1845. Lima abrupta, A. @Orbigny (non Goldfuss), ‘ Pal. Frang. Terr. Crét.’ vol. 111.
p. 559, pl. eccexxii. f. 6-9.

1850. Lima subabrupta, A. d’Orbigny, ‘ Prodr. de Pal.’ vol. ii. p. 167 ; 1870. F. J.
Pictet & G. Campiche, ‘ Foss. du Terr. Crét. de Ste. Croix,’ Matér. Pal. Suisse, ser. 5,
pt. iv. p. 169.

Remarks.—I have seen only two imperfect specimens of this
species ; it has not been previously recorded in England.

Distribution.—England: Chalk Rock of Winchester. Northern
France: in the zones of Scaphites equalis, Pachydiscus peramplus,
and Spondylus truncatus of Loir-et-Cher.

Family Spondylide, Gray.
Genus Sponpyivs, Linneus, 1766.

SPONDYLUS spPrnosus (Sowerby), 1814.

1814. Plagiostoma spinosa, J. Sowerby, ‘ Min. Conch.’ vol. i. p. 177, pl. Ixxviii.
f. 1-3; 1822. G. A. Mantell, ‘ Foss. S. Downs,’ p ps 203hpl. xxv. f.. 10; 1822, iA:
Broneniart, Descer. géol. des Envir. de Paris,’ pp. 251, 320, pl. ive te 2

1827. Plagiostoma spinosum, S. Nilsson, ‘ Petrif. Suecana,’ se 25 ; 1833 ? (young),
S. Woodward, ‘Geol. Norfolk,’ p. 40, pl. v. f. 25; 1837. . Hisinger ‘ Lethea
Suecica,’ p. 5A, Dl. xviat. Ai,

1819. ? Spondylus podopsideus, J. B. de Lamarck, adres sans Vert.’ vol. vi.
p. 194.

1819. ? Plagiostoma sulcata, J. B. de Lamarck, ‘ Animaux sans Vert.’ vol. vi
p- 161.

1820. Pectinites aculeatus, EK. T. v. Schlotheim, ‘ Die Petrefactenkunde,’ p. 228.

1822. ? Plagiostoma brightonensis, G. A. Mantell, ‘Foss. 8. Downs,’ p. 204,
ple xv. £2 15.

1825. Pachytos spinosus, Defrance, ‘ Dict. des Sciences nat.’ vol. xxxvil. p. 207,
ploixxvin: f 2, pl. lxxux. f 1.

1825. ? Pachytos striatus, Defrance, ‘ Dict. des Sciences nat.’ vol. xxxvil. p. 207.

1836. Spondylus spinosus, A. Goldfuss,-‘ Petref. Germ.’ vol. ii. p. 95, pl. ev. f. 5;
1838. H. G. Bronn, ‘ Lethewa Geogn.’ p. 684, 2nd ed. (p. 280, vol. ii. 3rd ed.), pl. xxxil.
f. 6; 1839. H. B. Geinitz, ‘Char. d. Schicht. u. Petref. des sachs. Kreidegeb.’
pt. i. p. 24; 1841. F. A. Romer, ‘ Die Verstein. des norddeutsch. Kreidegeb.’ p. 58 ;
1843-47. A. d’Orbigny, ‘Pal. Frang. Terr. Crét.’ vol. iii. p. 673, pl. cccclxi. f. 1-4;
1846. H. B. Geinitz, ‘Grundriss der Verstein.’ p. 474; 1846. A. E. Reuss, ‘Die
Verstein. der bohm. Kreideformat.’ pt. 11. p. 36; 1849. H. B. Geinitz, ‘ Das Quader-
sandst. in Deutschl.’ p. 196; 1850. A. d’Orbigny, ‘Prodr. de Pal.’ vol. ii. p. 254:
1850? A. Alth, ‘Geogn.-pal. Beschreib. der nachst. Umgeb. von Lemberg,’
Haidinger’s Naturwiss. Abhandl. vol. iii. pt. ii. p. 250; 1854. J. Morris, ‘Cat. Brit.
Foss.’ 2nd ed. p. 182 ; 1869 ? E. Favre, ‘ Moll. Foss. dela Craie des Envir. de Lemberg,’
p. 158; 1870. F. Romer, ‘Geol. von Oberschlesien,’ p. 315, pl. xxxiv. f. 11; 1872.
H. B. Geinitz, ‘ Das Elbthalgeb. in Sachsen, Paleeontographica, vol. xx. pt. ii. p. 31,
pl. ix. f. 1-3; 1889. A. Fritsch, ‘Stud. im Gebiete der bohm. Kreideformat.’
IV. Die Teplitzer Schichten,’ p. 85, f. 81; 1889. E. Holzapfel, ‘ Die Mollusken der
Aachener Kreide,’ Paleontographica, vol. xxxv. p. 243, pl. xxvii. f. 12 & 13.

1836. Spondylus dwplicatus, A. Goldfuss, ‘ Petref. Germ.’ vol. ii. p. 95, pl. ev. f. 6
1839. H. B. Geinitz, ‘Char. d. Schicht. u. Petref. des sachs. Kreidegeb.’ pt. i. p. 25
1841. F. A. Romer, ‘ Die Verstein. des norddeutsch. Kreidegeb.’ p. 58.

1854. P Spondylus brightonensis, J. Morris, ‘Cat. Brit. Foss.’ 2nd ed. p. 182.

1877. Spondylus spinosus var. duplicatus, A. Fritsch, ‘Stud. im Gebiete der
bohm. Kreideformat. II. Die Weissenberger u. Malnitzer Schichten,’ p. 138, f. 132.

1881. Lima spinosa, R. Etheridge,in Penning & Jukes-Browne’s ‘ Geol. neighb. of
Cambridge,’ Mem. Geol. Surv. pp. 65, 69 & 72.

Gira. S. No. 211. 2D

386 | MR. H. WOODS ON THE MOLLUSCA [Aug. 1897,

Remarks.—This species is fairly common in the Chalk Rock. In
Westphalia it is a characteristic fossil of the Reusstanwm-zone, and
in Saxony of the Scaphites-beds. Sowerby’s types are preserved in
the British Museum, but I have not been able to trace the specimens
figured by Mantell. Judging from the figure alone, I think it
probable that Mantell’s Plagiostoma brightonensis will prove to be
identical with this species. Sp. spinosus shows considerable varia-
tion in proportions and in the number of spines, but there is
a perfect gradation between the different forms.

In various Memoirs of the Geological Survey of England (for ex-
ample, nos. 15,17, 21, 25, & 31 of the bibliographic list given on p. 71
of Part I. of this paper) this species has been referred to the genus
Lima, but I do not know on what grounds, since it differs from
Lima in the inequality of the valves, the absence of the area on the
right valve, and the character of the ornamentation. As long ago
as 1828 it was clearly shown by Deshayes! that this and other
Cretaceous species on which the genera Dianchora, Sowerby,”
Podopsis, Lamarck,*? and Pachytos, Defrance,* were founded, differ
from Spondylus only in the fact that certain parts of the shell
have been removed by water in solution. Deshayes states that the
shell in existing species is formed of an outer thin layer and an
inner thick layer, and that the former is absent on the area. The
inner layer has been removed from the Chalk specimens, and this
accounts for the thinness of their shells, and the absence of the
muscular impression and area. The greater solubility of the inner
layer is due to the fact that it consists of aragonite,’ whereas the
outer layer is calcite. The triangular opening under the umbo,
which results from the removal of the area, was regarded by
Sowerby as having served for the passage of the byssus; but, since
these forms were attached by the left valve, an organ of fixation
would have been useless. In no case have I seen the teeth of
Sp. spinosus, but certain casts, which probably belong to this species,
give indications of them. Since the area is missing, the teeth
would obviously not be found on the left valve ; a specimen of the
right valve in the Wiltshire Collection (Woodwardian Museum)
shows distinctly the interior of the shell and the hinge-line, but
there are no teeth visible; another specimen which I cleaned out
agrees with this one. The absence of teeth is explained by the
circumstance that they consist entirely of aragonite: a section of
Sp. aurantius, Lamk., which I have had prepared shows this clearly.
The section is cut perpendicular to the hinge-line, and passes through
a tooth, the area, and the umbo. The thin outer layer referred to
by Deshayes consists of fine prisms arranged obliquely and rather
irregularly ; it does not pass beyond the umbo. ‘The inner layer

1 Aun. Sci. Nat. vol. xv. (1828) p. 427; also ‘Coq. Foss. des Envir. de
Paris,’ vol. i. (1830) p. 318.

2 ‘Min. Conch.’ vol. i. (1815) p. 183.

3 ‘Hist. nat. des Animaux sans Vert.’ vol. vi. pt. i. (1819) p. 194.

4 ‘Dict. Sci. Nat.’ vol. xxxvil. (1825) p. 207.

5 Sorby, Pres. Addr., Quart. Journ. Geol. Soc. vol. xxxv. (1879) Proc. p. 60.

eee

-_

Vol. 53.] OF THE CHALK ROCK. 387

near the middle of the valve is about three times the thickness of
the outer layer; it possesses an indistinct and irregular prismatic
structure, but a high power shows two sets of fibres crossing each
other obliquely ; this layer is traversed by numerous parallel tubes
placed at right angles to the surface, but at the umbo, where the
shell is thicker, they radiate outward so as to become perpendicular
to the outside of the shell. This layer thins out on the area towards
the hinge-line. The teeth and the main part of the area are formed
of large distinct prisms placed more or less parallel to the surface,
but bending inward, and they are crossed obliquely by tubules.
On the outer surface of the area is a thin layer which tapers in
passing from the hinge-line, and is absent in the neighbourhood
of the umbo; this layer has a finer structure, and under a high
power appears to be fibrous ; it is not traversed by tubules.

Distribution.—England: in the upper part of the Middle Chalk
(namely: zones of Terebratulina gracilis, Holaster planus, & Hetero-
ceras Reussianum), and throughout the Upper Chalk. Chalk Rock
(Reussianum-zone) of Shalecombe and Brixton (Isle of Wight), Win-
chester, Cuckhamsley, Bledlow, Wycombe, Princes Risborough, Box-
moor, Luton, Reed, Barkway, Great Chesterford, Westley Waterless,
and Underwood Hall near Dullingham. Jreland: Hibernian Green-
sand (Chloritic Sandstone division) and White Limestone. France:
zone of Inoceramus labiatus at Joigny (Yonne), etc. ; zone of Tere-
bratulina gracilis at Hauteville, Cyosing,in the Yonne and Aube, ete.
zone of Micraster breviporus of Cambrai, and at Partout (Yonne)
zone of Holaster planus, east of the Paris basin ; zone of Epiaster
brevis at Guise, etc.; zones of Spondylus spinosus and Sp. truncatus
in Loir-et-Cher; zone of Micraster cor-anguinum at Lezennes.
Belgium: Hervien of Limbourg. North-western Germany: zone of
Heteroceras Reussianum in Westphalia. Saxony: Plainer-Kalk of
Strehlen, Weinbohla, ete.; Brongniarti-Planer of Cottauer Berge ;
and the Glauconitic Marl and Planer. Silesia: Scaphites-beds of
Oppeln. Bohemia: Weissenberg, Malnitz, and Teplitz Beds.
Bavaria: Kagerhoh Beds.

SPoNDYLus LATUS.(Sowerby), 1815.

1815. Dianchora lata, J. Sowerby, ‘Min. Conch.’ vol. 1. p. 184, pl. Ixxx. f. 2;
1822. G. A. Mantell, ‘ Foss. S. Downs,’ p. 205, pl. xxvi. f. 21. ©

1822. ? Dianchora obliqua, G. A. Mantell, ‘ Foss. 8. Downs,’ p. 206, pl. xxv. f.1 &
pl xx. £12.

1836. Spondylus lineatus, A. Goldfuss, ‘ Petref. Germ.’ vol. ii. pl. cvi. f. 3, p. 97;
1839. H. B. Geinitz, ‘ Char. d. Schichten u. Petref. des sachs. Kreidegeb.’ pt. 1. p. 25
(pl. xx. f. 89 ?); 1841. F. A. Romer, ‘ Die Verstein. des norddeutsch. Kreidegeb.’
p. 59; 1846. A. E. Reuss, ‘ Die Verstein. der bohm. Kreideformat.’ pt. ii. p. 36, pl. xl.
f. 7-9; 1847. J. Muller, ‘ Petref. der Aachener Kreideformat.’ pt. 1. p. 34; 1850. H.
B. Geinitz, ‘Das Quadersandsteingeb. in Deutschl.’ p. 194 (partim); 1850. A.
d@Orbigny, ‘ Prodr. de Pal.’ vol. ii. p. 254; 1850? A. Alth, ‘ Geogn.-pal. Beschreib.
der nachst. Umgeb. von Lemberg,’ Haidinger’s Naturwiss. Abhandl. vol. iii. pt. ii.
p. 250; 1869? E. Favre, ‘ Moll. Foss. de la Craie des Envir. de Lemberg,’ p. 158.

1841. Spondylus latus, F. A. Romer,‘ Die Verstein. des norddeutsch. Kreidegeb.
p. 59; 1842. H. B. Geinitz, ‘Char. d. Schichten u. Petref. des sichs.-béhm. Kreidegeb.
pt. il. p. 82; 1850. J. de C. Sowerby in F. Dixon’s ‘Geol. Sussex,’ p. 356, pl. xxviii;
f. 30 & 31; 1854. J. Morris, ‘ Cat. Brit. Foss.’ 2nd ed. p. 182; 1872. H. B. Geinitz.
‘Das Elbthalgeb. in Sachsen,’ Palzontographica, vol. xx. pt. i. p. 187, pl. xlii. f. 4-€

2p 2

388 | MR. H. WOODS ON THE MOLLUSCA [Aug. 1897,

& pt. ii. p. 32, pl. viii. f. 18-21; 1877. A. Fritsch, ‘Stud. im Gebiete der bohm.
Kreideformat. II. Die Weissenberger u. Malnitzer Schichten,’ p. 138; 1889.
Fritsch, ibid. IV. ‘Die Teplitzer Schichten,’ p. 86, f. 82; 1889. E. Holzapfel; ‘ Die
Mollusken der Aachener Kreide.’ Palzeontographica, vol. xxxv. p. 244, pl. xxvii.
f. 11,14; 1892. E. Stolley, ‘ Die Kreide Schleswig-Holsteins,’ Mitth. a. d. mineralog.
Institut der Univ. Kiel, vol. i. p. 236.

1842. Spondylus obliquus, H. B. Geinitz, ‘Char. d. Schichten u. Petref. des sichs.-
bohm. Kreidegeb.’ pt. ili. p. 82; 1846. A. E. Reuss, ‘ Die Verstein. der bohm.
Kreideformat.’ p. 36, pl. xl. f.4; 1850. H. B. Geinitz, ‘Das Quadersandsteingeb. in
Deutschl.’ p. 194 (parti).

1870. Spondylus striatus, F. Romer, ‘ Geol. von Oberschlesien,’ p. 315, pl. xxxvii.
£.3 &4.

Remarks.—This species is much less common in the Chalk Rock
than is Sp. spinosus. Sowerby’s type came from the Chalk of
Lewes, and is now in the British Museum, as is also the specimen
figured by Dixon. Mantell’s Dianchora obliqua (from near Lewes
and Brighton) is probably identical with this species, but I have not
been able to find the type.

A ffinities.—Sp. latus is related to Sp. striatus, Sowerby, the type
of which comes from the Warminster Greensand (Rye Hill Sand’);
but its length is proportionately greater, it is more oval, and the
ribs are finer and more numerous.

Distribution.—England: Lower and Middle Chalk (zones of
Terebratulina gracilis, Holaster planus, & Heteroceras Reussianum),
and Upper Chalk. Chalk Rock of Brixton, Winchester, Cuckhamsley,
Thickthorn Hill (Bledlow), Boxmoor. France: zone of Terebra-
tulina gracilis, at Voulpaix, in the Yonne and Aube, etc.; zone of
Micraster cor-anguinum at Lezennes. North-western Germany : in
the zone of Heteroceras Reussianum. Aachen: Mucronata-beds of
Schneeberg. Sawony: Unter-Pliner (Upper Cenomanian) of .
Gross-Sedlitz near Pirna; Pliner-Kalk of Strehlen and Weinbohla.
Silesia: Scaphites-beds of Oppeln. Schleswig-Holstein: Quadrata-
beds (Senonian) of Lagerdorf. Bohemia: Teplitz Beds.

Genus Pricaruna, Lamarck, 1801.

Pricatuta Barroisi, Peron, 1887. (Pl. XXVII. figs. 18 & 19.)

1846. Plicatula pectinoides, A. E. Reuss (non Sowerby), ‘ Die Verstein. der bohm.
Kreideformat.’ pt. 11. p. 37, pl. xxxi. f. 16 & 17.

1872. Plicatula nodosa, H. B. Geinitz (non Dujardin), ‘ Das Elbthalgeb. in Sach-
sen,’ Paleontographica, vol. xx. pt. 11. p. 32, pl.ix.f.5; 1878. C. Barrois, ‘Terr. Crét.
des Ardennes,’ Ann. Soc. géol. Nord, vol. v. p. 891; 1889. A. Fritsch. ‘Stud. im
Gebiete der bohm. Kreideformat. [V. Die Teplitzer Schichten,’ p. 86, f. 83; 1895.
Plicatula cf. nodosa, B. Lundgren, ‘ Molluskfaunan i Mammill.- och Mucron.-
zonerna i nordéstra Skfne,’ K. Svenska Vet.-Akad. Handl. n.s. vol. xxvi. no. 6, p. 41.

1887. Plicatula Barroisi, A. Peron, ‘ Notes pour servir 4 l’ Hist. du Terr. de Craie,’
Bull. Soc. Sci. hist. nat. de ?Yonne, ser. 3, vol. xi. p. 167, pl. i. f. 5-7.

Remarks.— D’Orbigny * considered that this species (which was
figured by Reuss as P. pectinoides) was identical with P. nodosa,
Dujardin,’ and this view has been adopted by Geinitz and Fritsch.
Barrois pointed out that the species under consideration differs
considerably from P. nodosa, and Peron has since described it under

1 See Jukes-Browne, Geol. Mag. 1896, p. 261.
2 «Prodr. de Pal.’ vol. ii. (1850) p. 254.
3 Mém. Soc. géol. France, vol. 11. (1837) p. 228 & pl. xv. f. 14.

Wel. 53-| OF THE CHALK ROCK. 389

the name of P. Burroisi. The only English specimens that 1 have
seen were collected by Mr. R. M. Brydone. P. nodosa itself comes
from Touraine.

Affinities.—P. nodosa, Dujardin, differs from P. Barroisi in being
about four times larger, more elongated, and ornamented with large,
simple, widely-separated ribs.

Distribution.—Hngland: Chalk Rock of Winchester. France:
zones of Belemnitella plena, Inoceramus latiatus, Terebratulina
gracilis, Epiaster brevis, & Belemnitella quadrata, north and east
of the Paris basin. Savony: Plainer-Kalk of Strehlen. Bohemia:
Reuss’s specimens came from the Pliner-Kalk and Pyrope-Sand of
Triziblitz, and the Planer-Mergel of Weberschan. Fritsch’s examples
are from the Teplitz Beds.

Family Cardiide, Lamarck.
Genus Carpium, Linneus, 1758.

CARDIUM TURONIENSE, sp. nov. (Pl. XXVII. figs. 20-22.)

Deseription.—Shell small, oblique, oval, inflated, higher than
long; umbones prominent. Ornamented with plain ribs, separated
by furrows of about the same width; with indistinct pits in the
furrows. About ten ribs in aspaceof 3mm. Size of a specimen:
length=6 mm.; height=7 mm.

Affinities —The ornamentation is coarser and the shell more
oblique than in C. lineolatum, Reuss. The ornamentation is some-
what similar to that in C. cenomanense, d’Orbigny, but the ribs are
less numerous than in that species, and the form of the shell is
quite different.

Remarks.—This is a rare species; the only forms seen are in the
Montagu Smith Collection.

Distribution.—Chalk Rock of Cuckhamsley.

Carpium sp.,¢f. cpNoMANENSE, d'Orb. (Pl. XXVII. figs. 23 & 24.)
1843-47. A. d’Orbigny, ‘ Pal. Frang. Terr. Crét.’ vol. iii. p. 37 & pl. cexlix. f. 5-9.

Remarks.— A species of Cardium, agreeing in form with C. ceno-
manensé, 1s represented by several specimens from Cuckhamsley, but
all are in the condition of internal casts, so that their determination
must remain doubtful for the present. Size of a specimen: length
=9 mm.; height=9 mm.; thickness=8 mm.

Distribution.—Chalk Rock of Cuckhamsley (Montagu Smith
Collection.)

Carpium sp., cf. Marripanum, d’Orbigny.
1843-47. A. d’Orbigny, ‘ Pal. Frang. Terr. Crét.’ vol. iii. p. 40 & pl. cclvi. f. 7-12.
Remarks.—There is one specimen in the Montagu Smith Collec-
tion which probably belongs to this species, but only a small portion
of the shell on the posterior part of the right valve is preserved.
Distribution.—Chalk Rock of Cuckhamsley. D’Orbigny obtained
specimens from the Lower Chalk of Rouen, etc.

390 _ MR. H. WOODS ON THE MOLLUSCA (Aug. 1897,

Family Astartide, Gray.
Genus Carpita, Bruguiére, 1789.

CaRDITA CANCELLATA, Sp. nov. (Pi. XXVIII. figs. 2-5.)

Cf. C. tenuicosta, F. Nétling (non Sowerby), ‘Die Fauna der baltisch. Cenoman-
Geschiebe,’ Palaont. Abhandl. vol. ii. (1885) p. 29 & pl. v. f. 4; and Geinitz, ‘ Das
Elbthalgebirge in Sachsen,’ Paleontographica, vol. xx. pt. ii. pl. xvi. f. 11-18.

Description.—Shell oval, somewhat inflated, with the part from
the umbo to the posterior margin slightly depressed ; a little longer
than high. Anterior side shorter and smaller than the posterior.
Ventral margin curved. Ornamentation cancellated, consisting of
numerous concentric and radiating ribs—the two sets being of about
equal size. Size of an average specimen: length=16 mm.; height
=14 mm.

Remarks.—This is a fairly common species at Cuckhamsley, but
seems to be rare in other places.

Affinities.—This species is related to C. tenuicosta, Sowerby,
found in the Gault, but that form has a more quadrangular and
compressed shell, and its ornamentation consists of radiating ribs
only, crossed by growth-lines.

Distribution.—Chalk Rock of Cuckhamsley, Thickthorn Hill
(Bledlow), and Luton.

Family Arcticidz, Newton.
Genus Arcrica, Schumacher, 1817.

Arctica gQuapRaTa (d’Orbigny), 1848. (Pl. XXVII. fig. 25;
Pl. XXVIII. fig. 1.)

1840. Isocardia cretacea, H. B. Geinitz, ‘Char. d. Schicht. u. Petref. des sachs.
Kreidegeb.’ pt. ii. p. 53, pl. xi. f. 6 & 7.

1843. Cyprina quadrata, A. @Orbigny, ‘ Pal. Frang. Terr. Crét.’ vol. ii. p. 104,
pl. cclxxvi.; 1850. A. d’Orbigny, ‘ Prodr. de Pal.’ p. 161; 1850. H. B. Geinitz, ‘ Das
Quadersandst. oder Kreidegeb. in Deutschland, p. 156; 1869. F. J. Pictet & G.
Campiche, ‘ Foss. des Terr. Crét. de Ste. Croix,’ Matér. Pal. Suisse, ser. 5, pt. iii.
p. 225, pl. cxy. f. 83-5; 1877? A. Fritsch, ‘ Stud. im Gebiete der bohm. Kreideformat.
II. Die Weissenberger u. Malnitzer Schichten,’ p. 116, f. 76; 1873. H. B. Geinitz,
‘Das Elbthalgeb. in Sachsen,’ Paleontographica, vol. xx. pt. ii. p. 62, pl. xvii. f. 14-16 ;
1883. A. Fritsch, ‘Stud. im Gebiete der béhm. Kreideformat. ILI. Die Iserschichten,’
p- 100, f. 65 ; 1895. E. Tiessen, Zeitschr. der Deutsch. geol. Gesellsch. vol. xlvii. p. 486.

Remarks.—This species was founded by d’Orbigny on casts from
the French Cenomanian. Mr. Jukes-Browne has sent me specimens
from the Chloritic Marl of Chard, one of which has the shell pre-
served. I have seen only four specimens from the Chalk Rock; one
(fig. 25) is in the form of an internal mould of both valves, but the
others have a considerable portion of the shell present. The latter
agree with the Chard specimen, and the internal mould is like
d'Orbigny’s figure.

Affinities—Geinitz considers that d’Orbigny’s Cyprina ligeriensis
and C’. Noueliana are identical with this species. CU. Noweliana was
founded on a cast. D’Orbigny considered that his C. quadrata was

“a

Vol. 53.) OF THE CHALK ROCK. 391

distinguished from C. ligertensis by its more quadrate form, the short
anterior part of the shell, and the larger posterior part. The type
of quadrata is a more convex shell than ligeriensis.

The species under consideration differs from C. regularis in the
umbones being more oblique and the posterior margin more trun-
cated.

Distribution.—England: Chloritic Marl of Chard; Chalk Rock of
Morgan’s Hill near Devizes, Cuckhamsley, and Luton cutting.
France: Cenomanian of Rouen; zone of Pecten asper at Savigny ;
zone of Ammonites laticlavus at Blanc-Nez. Switzerland: ‘ Grés
vert supérieur’ of Ste. Croix. Saxony: Cenomanian Planer of
Plauen; Brongniarti Quader Sandstone of Posta, etc. ; Pliiner-Kalk
of Strehlen and Weinbohla. Bohemia: Weissenberg, Malnitz, and
Iser Beds.— Bavaria: Regensburg Beds.

Arctica? EQUIsULCATA, Sp. nov. (Pl. XXVIII. figs. 6-8.)

Description.—Shell moderately convex, subquadrate, oblique ;
umbones pointed, rather anterior. Shell rather thick, ornamented
with numerous regular, parallel, concentric grooves—about 15 in
10mm. Hinge unknown. Adductor-impressions well marked.
Approximate size: length=32 mm.; height=29 mm.

Remarks.—This species is imperfectly known at present, but
since the ornamentation appears to be quite distinct I have ventured
to give it a specific name. There are seven examples of it in the
Montagu Smith Collection, six being internal casts.

Distribution.—Chalk Rock of Cuckhamsley.

Genus Traprzium, Megerle v. Mihlfeldt, 1811.

TRAPEZIUM TRAPEZOIDALE (Romer), 1841. (Pl. XXVIII. figs. 9 & 10.)

1841. Crassatella trapezoidalis, F. A. Romer, ‘ Die Verstein. des norddeutsch.
Kreidegeb.’ p. 74, pl. ix, t. 22; 1846. A. d’Archiac, Mém. Soc. géol. France, ser. 2,
vol. ii. p. 802.

1849. Cyprina trapezoidalis, H. B. Geinitz, ‘Das Quadersandst. in Deutschl.’
p. 158 (partim); 1873. H. B. Geinitz, ‘ Das Elbthalgebirge in Sachsen,’ Palzonto-
graphica, vol. xx. pt. i. p. 229, pl. 1. f. 6 (?f. 5).

1850. Cypricardia trapezoidalis, A. d’Orbigny, ‘Prodr. de Pal.’ vol. i. p. 240;
1889? E. Holzapfel, ‘Die Mollusken der Aachener Kreide,’ Paleontographica,
vol. xxxv. p. 179.

Description —Shell inflated, trapezoidal, anteriorly short and
rounded, posteriorly elongate and angular. Ventral margin slightly
curved, nearly parallel to the hinge-line. Posterior margin nearly
straight, forming an obtuse angle with the hinge-margin. Umbones
much curved, reaching almost to the end of the hinge-line. A
sharp carina, gently curved, extends from the umbo to the posterior
angle, and cuts off a slightly concave and triangular area. Surface
with concentric lines.

Remarks.—This is a very rare species in the Chalk Rock; all the
specimens seen are casts, but one shows a small fragment of shell.
The type is stated by Romer to have come from the Pliner-Kalk of
Strehlen ; but Geinitz has never found the species in that locality.

392 _ MR. H. WOODS ON THE MOLLUSCA [Aug. 1897, |

Affinities—The shell in Cypricardia galiciana, KH. Favre’ (from
near Lemberg), is relatively shorter, more ovoid, and the umbones
less recurved. Crassatella tricarinata, Romer,’ is also more ovoid
than trapezoidalis, and the umbones are less anterior in position.

Mstribution—England: Chalk Rock of Cuckhamsley, Princes
Risborough, Thickthorn Hill (Bledlow), and Luton cutting. Ireland:
White Limestone. Sawvony: Cenomanian of Plauen (fide Geinitz) ;
Planer-Kalk of Strehlen (fide Romer). Bavaria: Kagerhoh Beds
of Kagerhoh.

TRAPEZIUM RECTANGULARE, sp. nov. (Pl. XXVIIT. figs. 11 & 12.)

Description.—Shell oblong, moderately convex, anteriorly short
and rounded, posteriorly elongate. Hinge-margin and the ventral
margin nearly straight and parallel. Posterior margin nearly
straight, and almost at right angles to the hinge-margin. Umbones
not prominent. Carina obtuse, extending in a curve from the
umbo to the posterior angle, and cutting off a triangular and
slightly convex area. In the interior a septum extends from the
umbo towards the anterior-ventral margin. Size of a specimen:
length=19 mm.; height=11 mm.

Affinities.—The shell in this species is flatter than in 7. trape-
zoidale, the umbones are less prominent, and the posterior margin
forms a right angle with the hinge-margin. It differs from
7’. parallelum, Alth,’ in being relatively shorter, in the anterior part
being very short, and in the ventral margin being nearly straight.

Distribution.—I have seen only four examples of this species, all
of which come from Cuckhamsley, and are in the Montagu Smith
Collection. A small piece of shell is preserved on one specimen,
and is almost smooth.

Family Lucinidz, Deshayes.
Genus Corsis, Cuvier, 1817.

Corsis? Morisoni, sp. nov. (Pl. XXVIII. figs. 13 & 14.)

Description.—Shell much inflated, rounded, inequilateral, slightly
longer tnan wide. Umbones moderately prominent, close together,
curved anteriorly. Surface with well-marked lines of growth.
Hinge unknown. Size of a specimen: length=14 mm.; height
=15 mm.

Remarks.—I have seen only two specimens of this species ; one
is a cast of the left valve, the other is a right valve with a portion
of the shell preserved. With this limited material at my disposal
it is impossible to give a full description of the characters of this
species.

Distribution.—Chalk Rock of Cuckhamsley.

1 «Descr. Moll. Foss. de la Craie des Envir. de Lemberg en Galicie,’ 1869,
p. 109 & pl. xii. f. 3.

* ‘Die Verstein. des norddeutsch. Kreidegeb.’ (1841) p. 74 & pl. ix. f. 28.

3‘Geogn.-pal. Beschreib. der nachst. Umgeb. v. Lemberg, Haidinger’s
Naturwiss. Abhandl. vol. iii. pt. ii. (1850) p. 229 & pl. xii. f. 8.

Vol. 53. | OF THE CHALK ROCK. 393

Family Pholadide, Leach.
Genus Marresta, Leach, 1824.

Marrusia ? RoTUNDA (Sowerby), 1850. (Pl. XXVIII. figs. 15-18.)

1850. ? Teredo rotundus, J. de C. Sowerby in F. Dixon’s ‘Geol. Sussex,’ p. 346,
pl. xxvii. f. 27 & 28.

Description. Umbonal groove well marked, only a little oblique:
in front of it the surface is ornamented with strong radiating ribs
crossed by finer and closer concentric ribs; just behind the groove
are two radiating ribs and on the rest of the shell concentric grooves
only are seen.

The cast of the interior is oval in form, narrowing posteriorly,
rounded in front and apparently also behind; it shows that the
large anterior gape was closed by a callus; behind the umbonal
groove is a cast of a ridge or process extending towards the posterior
margin. Size of the cast: length=7 mm.; heighbt=5°5 mm.

Remarks.—I have seen only one specimen of this, consisting of a
perfect internal cast and a mould of a portion of the exterior; it is
not sufficiently perfect to enable me to determine the genus with
certainty ; but I think that, on the whole, it is more likely to be
Martesia than Pholadidea. Sowerby figured, under the name of
Teredo rotundus, a fragment from the Chalk of Kent showing the
ornamentation, and also a cast; from the former, I believe it is
probable that the Chalk Rock specimen belongs to the same species,
but I have not been able to confirm this view by an examination of
the type, which appears to have been lost.

Distribution.—Chalk Rock of Cuckhamsley.

Family Cuspidariide, Fischer.
Genus Cuspiparta, Nardo, 1840.

CusrrpaRra CAUDATA (Nilsson), 1827. (Pl. XXVIII. figs. 19 & 20.)

1827. Corbula caudata, 8S. Nilsson, ‘ Petrif. Suecana,’ p. 18, pl. iii. f. 18; 1837.
W. Hisinger, ‘Lethea Suecica, p. 66, pl. xix. f. 12; 1840. A. Goldfuss, ‘ Petref.
Germ.’ vol. ii. p. 251, pl. cli. f. 17; 1846. A. E. Reuss. ‘Die Verstein. der bohm.
Kreideformat.’ pt. 1. p. 20, pl. xxxvi. f. 23; 1847. R. Kner, ‘ Verstein. Kreidemerg.
von Lemberg,’ Haidinger’s Naturwiss. Abhandl. vol. iii. pt. ii. p. 25, pl. v. f. 3;
1850. H. B. Geinitz, ‘Das Quadersandsteingeb. in Deutschl.’ p. 150; 1850.
A. dOrbigny, ‘ Prodr. de Pal.’ vol. i. p. 238; 1850 ?var., A. Alth, ‘Geogn.-pal.
Beschreib. der nachst. Umgeb. v. Lemberg,’ Haidinger’s Naturwiss. Abhandl. vol. ii1.
p. 237, pl. xi. f. 22; 1863. A.v. Strombeck, Zeitschr. Deutsch. geol. Gesellsch. vol. xv.
p. 147; 1873. H. B. Geinitz, ‘Das Elbthalgeb. in Sachsen,’ Paleontographica,
vol. xx. pt. 1. p. 67, pl. xxii. f. 19; 1877 PA. Fritsch, ‘Stud. im Gebiete der
bohm. Kreideformat. Il. Die Weissenberger u. Malnitzer Schichten,’ p. 125, f. 107 ;
1882. H. Schroder, Zeitschr. Deutsch. geol. Gesellsch. vol. xxxiv. p. 275 ; 1889. Fritsch,
‘Stud. im Gebiete der bohm. Kreideformat. IV. Die Teplitzer Schichten,’ p. 81 ;
1893. Fritsch, ibid. ‘ V. Die Priesener Schichten,’ p. 96.

1839-53. Neera caudata, G. P. Deshayes, ‘ Traité Elément. de Conchyliol.’ vol. 1.
p. 192; 1864. F. J. Pictet & G. Campiche, ‘Foss. du Terr. Crét. des Envir. de Ste.
Croix’ (Pal. Suisse, ser. 1x.), p. 42; 1869. E. Favre, ‘Moll. Foss. de la Craie des
Envir. de Lemberg,’ p. 102, pl. xi. f. 8; 1885. F. Noétling, ‘ Die Fauna der baltischen
Cenoman-Geschiebe,’ Palaont. Abhandl. vol. ii. p. 35, pl. vi. f. 7 ; 1889. O. Griepenkerl,
‘Die Verstein. d. Senon. Kreide v. Konigslutter,’ Paliont. Abhandl. vol. iv. p. 69.

1850. Leda pulchra, J. de C. Sowerby, in F. Dixon’s ‘Geol. Sussex,’ p. 346
(p. 382, 2nd ed.), pl. xxviii. f. 10; 1854. Leda? pulchra, J. Morris, ‘ Cat. Brit. Foss.’
2nd ed. p. 205.

394 "MR. H. WOODS ON THE MOLLUSCA [Aug. 1897,

Remarks.—I have seen only one example of this from the Chalk
Rock, which is in the Montagu Smith Collection; it shows the
concentric ribs, although the shell is not preserved. This specimen
agrees perfectly with Sowerby’s figure of Leda pulchra, but I have
not succeeded in tracing the type of that species; it is stated to
have come from the ‘Chalk of Kent.’ The English specimens,
and also the figures given by Goldfuss and Reuss, differ from the
type in having the posterior part of the shell much shorter; this,
however, is probably due to the preservation of the shell in Nilsson’s
original specimen.

Affinities.—Stoliczka * states that this species is closely allied to
his Necra detecta (from the Ootatoor Group), ‘ but it has the poste-
rior end still narrower and longer, and the beaks incurved in a
direction perpendicular to the longitudinal axis of the shell.’

Distribution.—Chalk of Kent (horizon unknown). Chalk Rock of
Cuckhamsley. Westphalia: zone of Ammonites ceesfeldensis (Upper
Senonian) of Ceesfeld. Saxony: Pliner-Kalk of Strehlen. Bohemia:
in the Weissenberg, Malnitz, and Teplitz Beds (fide Fritsch). Ba-
varia: Grossberg Beds of Marterberg near Passau. Galicia:
Nagorzany, near Lemberg (fide Favre).

IV. Distrrpurion AND RELATIONS OF THE FAUNA.

I have already pointed out that the fauna of the Reusstcanum-
zone has a wide range in Europe; it can be recognized, although
showing differences in passing from one region to another, in
Northern France, North-western Germany (Westphalia, Brunswick),
Saxony, Upper Silesia, Bohemia, and Bavaria. But, though
traceable in countries so distant as England and Bohemia, it is,
I believe, absent from the Belgian area; this is probably to be
accounted for by the very different conditions under which the
Cretaceous Series was deposited in Belgium. I hope, however, to
recur to this point after I have had further opportunities of.
studying the rocks of that country.

The area over which the Leussianum-zone can be traced
undoubtedly formed part of one life-province in the Cretaceous seas ;
this province seems to have remained fairly constant throughout the
Chalk period; it included what Munier-Chalmas” has termed the.
second or temperate zone, which he considers to have been
especially characterized, in Senonian and Upper Turonian times, by
the great development of the echinoids Micraster and Echinocorys.

Just as is the case in so many formations, the cephalopoda of the
Reussianum-zone have a much wider geographical range than the
gasteropoda and lamellibranchia; this is no doubt accounted for
by their more active mode of life. Of the 10 species of cephalopods
present in the Reussianum-zone in this country, 7 occur in Saxony
and 6 in Bohemia; but of the 16 gasteropods only 2 (or perhaps 3)
are found in Saxony and 2 in Bohemia; of the 29 species of
lamellibranchs about half have been recognized in Saxony and 11

1 ¢Cret. Fauna 8. India,’ Pal. Indica, vol. iii. (1870) p. 46, pl. in. f. 7
& pl. xvi. f. 15. 2 Comptes Rendus, vol. cxiv. (1892) p. 851.

[To face p. 394.

LIBRANCHIA FOUND IN THE CHALK Rock orn Reussianum-zoneg.

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f Inoceramus is not shown here.

he species 0

Quart. Journ. Geol. Soc. Vol. LIII. [To face p. 394.

III. Taste sHowine THE DistRIBUTION OF THE LAMELLIBRANCHIA FOUND IN THE Cat Rock or Reussianwm-zone.

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Cardium turontense ....1.0..00000e00 Woods * |
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sp., ef. Mailleanum | d’Orbigny | * |. *
Cardita cancellatd ....1....166 .....4 Woods be bl lboc|boo| bor a
Arctica Quadrata ....1.s....++ seveeeee] (WOrbigny) J %]...]...)...-..] ¥ [0] Mfecelee Peele ‘lleee|ledellood bod bas . ¥ ee) foe. *|%
» requisulcata | Woods Pe .| *
Trapezium trapezoidale .. (Romer) % |...) ¢|..-]-. fee E34) fieal bod laos| Goclbod koellood ¢ fr llsed hed {heel bel lane is
aa rectangulare Woods *
Corbis? Morisoni......... .| Woods es
Martesia ? rotunda ... .| (Sowerby) |e
Cuspidaria caUudata,...c0r..ccseee0e (Nilsson) H [ecc[ece[eceler cece Bed) Ged eee see oer) el ae Han : * baleen) bee #/ | *)..7 | #

1 The foreign distribution of the species of Znoceramus is not shown here.

Vol. 53.] OF THE CHALK ROCK. 395

or 12 in Bohemia. So far as I know, no species of cephalopod, with
the exception of Nautilus sublevigatus, d’Orb., is common to the
Chalk Rock and the Belgian Cretaceous beds.

The paleontological characters of the Meusstanum-zone as seen in
_ England are well maintained in the ‘Zone of Heteroceras Reussia-
nui and Spondylus spinosus’ (Schluter) of North-western Germany.
This is especially true as regards the cephalopoda, which have been
so carefully described by Prof. Schliiter; the gasteropoda and
lamellibranchia, however, are not so abundant nor so well preserved,
and have not yet been studied in detail.

In Saxony, the Pliner-Kalk of Strehlen (near Dresden) contains
the fauna we are now considering, with, perhaps, that of part of a
lower zone also. That rock can no longer be studied at Strehlen,
the site of the old exposure having been built over. The fossils,
however, have been fully described and figured in Geinitz’s great
work, ‘Das Elbthalgebirge in Sachsen,’ and the originals are pre-
served in the Dresden Museum. Even allowing for the possibility
that the Planer-Kalk includes a little more than the Reussianum-
zone, the number of species in that part of it is still considerably
greater than in the same zone in England. This is indeed what
we should expect from the fact that the Upper Cretaceous rocks of
Saxony were deposited in shallower water and much nearer the
shore-line than were those of the same age in England. ‘The greater
richness of the fauna is seen particularly i in the Lamellibranchia,
Gasteropoda, and Fishes; of these three groups Geinitz describes
about 50, 30, and 28 species respectively. There is no important
difference in the number of forms of Cephalopoda, Brachiopoda,
Echinoidea, and Actinozoa in the two countries ; but in the Planer-
Kalk the Asteroidea, Crinoidea, and Reptilia, which, so far as I
know (with the exception of a single specimen of Pentacrinus), are
not found in the Chalk Rock at all, are each represented by one or
two species.

The genera of gasteropods and lamellibranchs which are present
in the Planer-Kalk, but unknown in the Chalk Rock, are :—

Patella. Anomia. Crassatella.
fissoa. Glycimeris. Venus.
Turritella. Pinna. Isocardia.
Act@on. Gervillia. Lriphyla.

The species which are found in the Chalk Rock, but not in the
Planer-Kalk of Strehlen, are :—
Ptychoceras Smithi, Woods. Dentalium turoniense, Woods.

Heteroceras sp. Arca cf. Galliennei, d’Orb.
Emarginula Sancte-Catharine, Passy. Limopsis, sp.

aff. divistensts, Gard. Lima granosa, Sow.

Trochus Schhitert, Woods. », (Acesta?) subabrupta, a’ Orb,

3 berocscirensis, Woods. Cardium turoniense, Woods.
Turbo gemmatus, Sow. 5 ef. cenomanense, d’Orb.

» Geinitzi, Woods. re ef. Mailleanum, A Orb.
Cerithium cuckhamsliense, Woods. Cardita cancellata, Woods.

x Saundersi, Woods. Arctica? equisulcata, Woods.

Aporrhais (Lispodesthes) ) Mantel, Gard. Trapezium rectangulare, Woods.
Lampusia? s Corbis? Morisoni, Woods.

Aveliana cf. Humboldti, Mill. Martesia? rotunda (Sow.).

396 MR. H. WOODS ON THE MOLLUSCA [Aug. 1897,

The fauna of the Reussianum-zone in Bohemia is apparently also
richer than in our own country, but at present it is not possible in
all cases to say definitely which species come from that zone. Inthe
Tables showing the range of the moilusca (facing p. 394, and Part I.
pp- 92, 93), it will be noticed that some species, which in other
areas have a very limited range, pass through all or nearly all the
divisions in Bohemia. I believe that these divisions (‘ Weissen-
berg Beds’ etc.) are, to a large extent, geographical, rather than
zonal, in character.

It would be interesting to compare the English fauna with the
Bavarian ; but in this case too we meet with a difficulty, since, from

the available sources of information, it is not possible to separate

all the species found in the Pulverthurm Beds from those of the
other divisions of the Kagerhoh Beds.

As might be expected, there is no important difference between the
fauna of the Reussianum-zone in England and in Northern France.

I believe that few, if any, of the species which occur in the
Reussianum-zone have been identified, without doubt, as occurring
in extra-European areas, although some have certainly ‘ represen-
tative forms’ elsewhere.

Turning now to our own country, we find that the feature which
has struck everyone who has studied this zone is the general resem-
blance of its fauna to that of the Chalk Marl.—First : ammonoids,
gasteropods, and certain groups of lamellibranchs are abundant at
both horizons, whereas they are rare or absent in the intervening
beds. Secondly: some species are common tothe Reussianum-zone
and the Cenomanian, namely :—

Nautilus sublevigatus, @Orb. Aporrhais (Lispodesthes) Mantelli,
Crioceras ellipticum (Mant.). Gard.

Emarginula Sancte-Catharine, Passy. (?) Lnoceramus striatus, Mant.
Pleurotomaria perspectiva (Mant.). Spondylus latus (Sow.).

Turbo gemmatus, Sow. Arctica quadrata (d’Orb.).

Thirdly: allied forms occur at the two horizons, e.g. Baculites
bohemicus, Fritsch, Scaphites Geinitz, d@Orb., and Holaster planus
(Mant.) of the higher zone, are closely related to B. baculordes,
Mant., S. oblaquus, Sow., and H. trecensis, Leym., of the lower zone.

In England, the following species of mollusca are, so far as is
known at present, confined to the Reusseanum-zone :—

Ptychoceras Smithi, Woods. Arca cf. Galliennei, d’Orb.
Heteroceras Reussianum, d’Orb. , (Barbatia) ef. Geinitzi, Reuss.
i sp. Lima (Acesta ?) subabrupta, d’Orb.

Baculites bohemicus, Fritsch. Plicatula Barroist, Peron.
Prionocyclus Neptuni (Gein.). Cardium turoniense, Woods.
Turbo Geinitzi, Woods. i ef. cenomanense, d’Orb.
Trochus Schliiteri, Woods. a cf. Mailleanum, d Orb.

ie berocscirensis, Woods. Cardita cancellata, Woods.
Natica (Naticina) vulgaris, Reuss. Arctica? equisuleata, Woods.
Cerithium cuckhamslense, Woods. Trapezium trapezoidale (Rom.).

Pe Saundersi, Woods. < rectanqulare, Woods.
Avellana ct. Humboldti, Mull. Corbis? Morisoni, Woods.
Dentalium turoniense, Woods. | Martesia? rotunda (Sow.).
Nuculana cf. stliqua (Goldf.). Cuspidaria caudata (Nilss.).

1 On this subject see J. J. Jahn, ‘ Hinige Beitrage zur Kenutniss der bohm.
Kreideformat.’ Jahrb. d. k.-k. geol. Reichsanst. vol. xlv. (1895) p. 125.

Vol. 53.]

OF THE CHALK ROCK. 397

One of the most noteworthy points in the mollusca of the Reussia-
num-zone, as compared with those of the Cenomanian, is the rarity in
the former, of the three families Ostreide, Pectinide, and Limide.
All three are very important in the Lower Chalk.

Whether the Reusstanum-zone should be regarded as the lowest
zone of the Senonian or the highest of the Turonian appears to me
to be a point of no great importance. The forms which seem to
show that its relations are with the lower rather than the higher
division are Pachydiscus peramplus, Crioceras ellipticum, Turbo
gemmatus, Arctica quadrata, and Holaster planus. Others, however
—such as Spondylus spinosus, Lima (Plagiostoma) Hoperi, and the ~
species of Micraster, Cardiaster, and Echinocorys,—link it to the
Senonian. Probably the species of Jnoceramus, when fully worked
out, may furnish some evidence of importance on this point. On
the whole, I am inclined to think that the affinities of the fauna are
closer to the Turonian than to the Senonian.

The absence of crustacea in the Chalk Rock, with the exception
of a few specimens of Pollicipes, is somewhat remarkable, but the
rarity of this class of animals in deposits now forming was noticed
by the Challenger Expedition,’ and is attributed to the areolar
structure of the exoskeleton, ‘which admits of relatively rapid
solution after the death of the animal.’

It may be convenient for reference to give here a list of the
fossils, other than the mollusca, which are found in the Chalk
~ Rock :—

PIsceEs.

Oxyrhina Mantelli, Ag.”
Corax falcatus, Ag.
Ptychodus latissimus, Ag.

3 mammillaris, Ag.
CrirRIPEDIA,
Pollicipes sp.
CIUZTOPODA.

Serpula ampullacea, Sow.
+» plexus, Sow.

* sp.
BRACHIOPODA.

Rhynchonella Cuvieri, d’Orb.3
“5 plicatilis (Sow.).
var. Woodwardi,
Dav.
var. octoplicata
_ (Sow.).
a reedensis, Eth.

9 bb)

3) ”

BRACHIOPODA (cont.).

Terebratula carnea, Sow.
is semiglobosa, Sow.
Terebratulina striata (Wahl).
Trigonosemus incerta, ? Dav. (? young
specimen).?

CRINOIDEA.

Pentacrinus Agassizi, v. Hagen.

EcuINoIDEA.

Cardiaster ananchytis (Leske); ele-
vated variety.

Cidaris sp.

Cyphosoma radiatum, Sorig.

-, spatuliferum ?, Forbes.
Echinoconus conicus, Breyn.
Echinocorys vulgaris, Breyn., var.

gibbus (Lam.).
Holaster planus (Mant.).
Micraster breviporus, Ag.
mS cor-bovis, Forbes.

1 Murray & Renard, Challenger Rep. ‘ Deep-Sea Deposits’ (1891), p. 264.
2 For the determination of this species I am indebted to Mr. A. Smith

Woodward, F.G.S.

3 T am indebted to Mr. J. F. Walker for the determination of these species.

398 MR. H. WOODS ON THE MOLLUSCA [Aug. 1897,

ACTINOZOA. PoRiFERA (cont.).

Parasmilia centralis (Mant.). Placotrema cretaceum, Hinde.
Plinthosella squamosa, Zitt.*
Plocoscyphia convoluta (Smith).

PoRIFERA.
Jlexuosa (Mant.).

Camerospongia campanulata (Smith). Ventriculites aleyonoides, Mant.

subrotunda (Mant.). 4: angustatus, Rom.
Coscinopora infundibuliformis, Goldf. be decurrens, Smith.
Cystispongia subglobosa, Romer. ~ ‘ impressus, Sraith.
Guettardia stellata, Mich. mammillaris, Smith.
Leptophragma Murchisoni (Goldf.).* Verrucocelia tubulata ? ? (Smith).

V. ConbiITIONS UNDER WHICH THE CHALK Rock was DeEposrtTep.

To endeavour to determine the depth at which a fauna, composed
(with the exception of some of the foraminifera) of extinct species,
lived, may at first sight appear to be quite hopeless, since we know
that at the present day different species of a genus have often very
diverse ranges. I believe, however, that by a study of the predomi-
nating forms in a fauna, and their association, together with the
relative numbers of individuals and species, some conclusions of a
trustworthy nature may be arrived at.

That the fauna of the Reusstanwm-zone lived in water of less
depth than the faunas of the other Turonian and Senonian zones
will, I think, scarcely be disputed. The Chalk Rock is very thin
generally, yet fossils are more numerous specifically and far more
abundant individually than in the other zones. It is well known
that at the present day we find a similar difference in passing from
comparatively shallow water to greater depths: the number of
species, as well as the number of individuals, living on the sea-
bottom, diminishes considerably. In water of no great depth, the
nature of the materials forming the sea-bottom has a greater
influence on the character of the fauna than has the actual depth of
the water.? The relative richness of the fauna of the Reusstanum-
zone certainly cannot be accounted for by any difference in the
nature of the sea-bottom, since in its original soft state the
Chalk-ooze must have been, so far as animal life was concerned,
uniform in character throughout the Chalk period. We can, there-
fore, only conclude that the change in the fauna was caused by a
decrease in depth ; and, since the change is so marked, the decrease
was probably considerable.

The presence of glauconite-grains, which is one of the distinguish-
ing features of this zone, also lends support to the view just stated.
The Challenger Expedition® found that glauconite was ‘ almost
exclusively limited to terrigenous deposits in more or less close
proximity to the continental masses of land, while it was relatively

1 These species are here recorded from information supplied by Mr. Jukes-
Browne, whose specimens were determined by Dr. G. J. Hinde, F.R.S8.

2 See especially remarks by W. A. Herdman, Proc. Liverpool Geol. Soc.
vol, vii. pt. ii. (1894) p. 171; also Address, Rep. Brit, Assoc. (Ipswich) 1895,

p. 698.
3 Murray & Renard, Challenger Rep. ‘ Deep-Sea Deposits’ (1891), p. 382.

Vol. 53. ] OF THE CHALK ROCK. 399

rare or wholly absent from pelagic deposits situated towards the
centres of great ocean basins. .... It is also present in
samples of Globigerina-ooze situated at no great dis-
tance from the continents.’ ‘Glauconite may therefore be
regarded as having been formed in deep water not far from the
coasts, or in shallow water where no large quantity of continental
débris was deposited.’ Further, at the present day glauconite is
generally associated with phosphate of lime; this is what we find
too in the Chalk Rock—it is a nodular phosphatic deposit, containing
glauconite.

The rarity or absence of aragonite-organisms, even in the form
of casts, in the Upper Chalk, is considered by Mr. P. F. Kendall?
to be due to the fact that they were, like the shells of pteropods,
which form the main part of the modern Pteropod-ooze, dissolved
at a particular depth—not less than 1800 fathoms; for if these
organisms had remained for a short time on the floor of the Chalk
sea, some of them would have left traces of their existence in the
form of casts, since the soft Chalk-ooze would easily have filled up
the interiors of the shells. If this explanation be correct, then I
think we may safely take the abundance of casts of aragonite-
organisms (ammonoids, Nautilus, etc.) in the Reussianwm-zone as
an indication that it was formed in water of less depth than the
Upper Chalk, since the aragonite shells must have become covered up
with sediment and were not dissolved until some time afterwards."

We can scarcely doubt that the Chalk Rock was formed beyond
the limits of terrigenous deposits, and therefore presumably at a
depth of greater than about 100 fathoms. Both paleontological
and lithological evidence are entirely in favour of this. The
Benthos within the 100-fathom line would have been much richer
in species than is our Reussianum-zone ; just as the fauna of the
Planer-Kalk of Strehlen—particularly the gasteropoda and lamelli-
branchia—is more varied than. that of the Chalk Rock. If we
remember the extremely minute quantity of detrital material which
is present in the Chalk Rock, and if we compare a section of that
rock with sections of some samples of hardened Gilobigerina-ooze,
we can hardly doubt that the two deposits have been formed in the
same way.

That the Reussianum-zone was not laid down in very deep water
is shown by the character of its fauna; not only does it contain a
considerable variety of forms, but the number of individuals of any
species is, even in the same block of stone, often very large. This
is contrary to what is met with in abyssal regions at the present
day ; thus in the deep-sea Benthos the number of specimens of a
species, as well as the number of species, decreases with increasing
depth, and, apart from depth, a similar diminution in numbers is
noticed in tropical and subtropical regions as the distance from the
shore becomes greater. Another point is the large number of
gasteropods with thick shells, often of large size (such as Turbo,
Pleurotomaria), in the Reussianum-zone; at the present day most

' Rep. Brit. Assoc. (Liverpool) 1896, p. 791.

4.00 “MR. H. WOODS ON THE MOLLUSCA [Aug. 1897,

deep-sea animals are characterized by the possession of thin shells,
usually of rather small size. It might indeed be urged that the
occurrence of thick shells in the Chalk Rock can be explained by
the existence of a higher temperature than is found in the deep sea
at the present time, since Murray and Irvine’ have shown that the
secretion of carbonate of lime by organisms is directly related to
the temperature of the water ; but I know of no evidence in favour
of the Cretaceous temperature having been high enough to cause
any great change at abyssal depths.

In discussing the question of depth from the evidence supplied
by the genera of Mollusca which have living representatives we
must consider three main points :—(1) the genera which have a
limited bathymetrical range; (2) the depths at which the other
genera are most numerous; (3) the relative abundance of the genera
in the Reusstanum-zone itself.

So far as their range in depth is concerned, we may conveniently
divide the genera into five groups :—

1. The first includes Crepidula, Emarginula, Martesia, Ostrea,
Pheatula, and Trapezium, all of which are shallow-water
forms and, so far as I know, do not live at a greater depth
than 50 fathoms. These genera are all rare, and some of
them very rare, in the Reuwssianum-zone, and we cannot
therefore take them as a proof that the deposit was formed
in such shallow water.’

2. Pleurotomaria, Cardita, and Arctica do not live below a depth
of 200 fathoms.

Pleurotomaria is one of the commonest gasteropods in the
Reussianum-zone, and its evidence should therefore be of
considerable importance. Only four living species are
known ; they were dredged at various depths between 73 and
200 fathoms. Two species—P. Adansonia and P. Beyrichi,
both of large size—have been found at the greater depth.
It is, of course, possible that the range of the genus may have
been more extended in Mesozoic times when the number of
species reached its maximum; we know, at any rate, that
it is very common in several Jurassic formations which are
undoubtedly of shallow-water origin.

Cardita and Arctica are not common in the Chalk
Rock ; the former extends from the Littoral zone to
150 fathoms, and is found mainly in shallow water; the
latter ranges from the Laminarian zone down to about
180 fathoms.

1 Proce. Roy. Soc. Edin. vol. xvii. (1891) p. 79: J. Murray, ‘Summary of
Scientific Results (Challenger Exped.),’ pt. 11. (1895) p. 1456.

2 With regard tc genera which appear to be limited to shallow water, we
shall do well to bear in mind the warning given by Starkie Gardner :—‘ When
we reflect that, for one cast of the dredge in abyssal depths, a thousand have
perhaps been made in the littoral zone, we must hesitate to pronounce
definitely that any genus is without deep-sea species’ (Geol. Mag. 1884,
p- 497).

Moles3.| OF THE CHALK ROCK. 401

3. Turbo, Chlaniys, Spondylus, and Cardium are not found below
the 600-fathom line.

Turbo is very common in the Reussianwm-zone, ard one
of the species is of considerable size. At the present day
the genus extends from the Littoral zone down to 565
fathoms, but, being phytophagous, it is of course most
abundant in shallow water.

Chlamys is very rare, and Cardium not common, in the
Reussianum-zone ; both are abundant in fairly shallow water.

Spondylus is rather common, particularly Sp. spinosus.
The existing species live in warm seas, mainly in the Littoral
zone, or at no great depth, but one form, which is, how-
ever, quite small, has been found at a depth of 520 fathoms.

4. Natica is found down to about 1000 fathoms, but is abundant
only at less than 100 fathoms; it is moderately common in
the Reussianwm-zone.

Modiola extends down to 800 fathoms, but is not common
below 100 fathoms ; itis moderately rare in the Reussianum-
zone.

5. Ten genera—namely, Trochus, Aporrhais, Cerithium, Denta-
lium, Limopsis, Nucula, Arca, Cuspidaria, Nuculana (= Leda),
and Lima—have species which live at 1000 fathoms or
greater depths, but in every case these genera have a great
bathymetric range; all occur in shallow water, and nearly
all are found in depths of only a few (1 to 5) fathoms.

The living forms of Trochus' are abundant in the Littoral
and Laminarian zones, but the genus is not uncommon in
fairly deep water; indeed, Agassiz * speaks of the Trochidz
as being well represented in deep water. T'rochus is, 1
believe, the commonest gasteropod in the Reusstanwm-zone,
nevertheless it is represented by only two species; in water
of less than 100 fathoms there would almost certainly have
been a larger number of species.

Aporrhais is.also very common. Existing species are
most numerous within the 100-fathom line, and are not
common beyond it.

Cerithium: there are two species in the Chalk Rock, one
being very common. ‘The genus is abundant in the Littoral
zone or at no great depth, and rare beyond 100 fathoms.

Dentalium: the Dentaliide are characteristic of deep.
water, but also occur in shallow regions. The genus is.
somewhat rare in the Reussianum-zone.

Nucula and Arca are common in the Chalk Rock; they

1 Dr. W. F. Hume,‘ Nat. Sci.’ vol. vii. (1895) p. 391, has stated that the ‘ pre-
sence of Trechus, Turbo, and Solarium in the Chalk Rock is paralleled at the.
present day by the same association found at Culebra Island at a depth of
390 fathoms.’ Solariwm does not occur in the Chalk Rock, and the association
of Trochus and Turbo proves nothing, since they both occur in the Littoral
zone as well as at various greater depths,

2 «Three Cruises of the Blake,’ vol. ii. (1888) p. 67.

© 3.6.8. No: 211. Qf

402 MR. H. WOODS ON THE MOLLUSCA [Aug. 1897

are widely distributed in rather shallow water, and have also
some abyssal species.

Cuspidaria is found in all seas and at all depths, but the
species are most abundant in deep water and abyssal regions ;
since, however, only one specimen has been seen in the Chalk
Rock, we cannot take it as evidence of very deep water.

Nuculana (= Leda) also occurs at all depths, but is rather
a characteristic deep-water form.’ Only two specimens
have been found in the Chalk Rock.

To sum up the preceding evidence furnished by the Mollusca, we
see that we have in the Reussianum-zone some genera (Cuspidaria,
Nuculana, Dentalium) which are characteristic of deep water, but
are not confined to it; others which are limited to shallow water
(0 to 50 fathoms). But neither group forms the predominating
element in the Reusstanum-fauna; we may therefore consider that
this zone was not laid down either in shallow or in very deep
water. The commonest genera, although at the present day most
abundant in shallow or rather shallow water, do occur fairly often
in water of moderate depth (say from 100 to 500 fathoms), but
these genera, numerous in the Reusszanwm-zone as the individuals
may be, are there represented by only one or two species in
each case, whereas in shallow water they would almost certainly
have been represented by a larger number. I think, therefore, that
it is unlikely that the Aeusstanwm-zone was formed at a depth
greater than about 500 fathoms; this is further supported by the
fact that in dredging beyond this depth a marked decrease is
noticed in the number of individuals as well as species of both
lamellibranchia? and brachiopoda.’

I consider, then, that the Chalk Rock was laid down between the
depths of about 100 and 500 fathoms. From the number of
species found in it, several of which belong to genera common in
fairly shallow water, I think it was probably deposited somewhat
nearer the former than the latter limit, although the depth must
necessarily have varied in different places. The absence of the
Chalk Rock in Lincolnshire is most likely due to the greater depth
of water which existed in that region.

I have not studied in detail the other groups of fossils found in
the Feussianum-zone. I may, however, mention that the Hexacti-
nellid sponges are well represented, and therefore strongly favour
the view that the lower limit was not less than about 100 fathoms,

1 The occurrence of the genera Cuspidaria (= Neera), Nuculana (=Leda),
and Dentalium is noteworthy, since Dr. Gwyn Jeffreys and many later writers
have regarded the absence of these forms in the Upper Chalk as evidence in
favour of its shallow-water origin. On this subject see J. G. Jeffreys, Rep.
Brit. Assoc. for 1877 (1878), p. 86; J. S. Gardner, Geol. Mag. 1884, pp. 496-
506; A. R. Wallace, ‘ Island Life,” 2nd ed. (1892) p. 89.

2 E. A. Smith, ‘ Report on the Lamellibranchiata, Challenger Exped. (1885)

. 6.
ss T. Davidson, ‘Report on the Brachiopoda,’ Challenger Exped. (1880)
pp. 3, 4.

Wal. 53.1] OF THE CHALK ROCK, 403

since they do not live in water of less than 95 fathoms in.depth ;
they are abundant between 95 and 200 fathoms, and also from 301
to 700 fathoms.’

EXPLANATION OF PLATES XXVII. & XXVIII.

All the specimens figured come from the Chalk Rock, and, unless otherwise

-stated, are preserved in the Woodwardian Museum (Montagu Smith Collection).

The figures are of the natural size, except where otherwise stated.

Prats XXVII.

Figs. 1 & 2. Nucula sp. Internal moulds.
Fig. 3. Arca sp., ef. Galliennei, dOrbigny. Internal mould.
4, Arca sp. Internal mould.

Figs. 5&6. Arca (Barbatia) sp., cf. Geinitzi, Reuss. 5. Wax mould of exterior
showing ornamentation. 5a. Portion of same, x5. 6. Internal
mould.

Figs. 7 & 8. Limopsis sp. Internal moulds. x13.

Figs. 9-12. Modiola Cotte, Romer. 9,10. From Winchester (coll. R. M.
Brydone). 11. Part of a larger specimen from Luton (collected
by the Author). 11a. Portion of shell of the same enlarged, showing
the character of the ornamentation, x6. 12. Outline of section of
valve of the same specimen.

Fig. 13. Znoceramus striatus, Mantell.

Figs. 14-17. Znoceramus sp. Internal moulds. 15. Posterior view of 14.

Figs. 18&19. Plicatula Barroist, Peron, from Winchester (coll. R. M. Brydone).
2:

Figs. 20-22. Cardiwm turoniense, sp.nov. 20. Wax mould, x13. 20a. Portion
of same further enlarged, showing the character of the ornamentation,
x5. 21. Natural mould, x13. 22. Anterior view of the same,
lies

Figs. 23 & 24. Cardium, cf. cenomanense, d’Orbigny. Internal mould.
24. Anterior view.

Fig. 25. Arctica quadrata (@Orbigny). Anterior view of natural mould.
Morgan’s Hill, near Devizes (coll. A. J. Jukes-Browne).

Puate XXVIII.

Fig. 1. Arctica quadrata (d’Orbigny). Right valve.

Figs. 2-5. Cardita cancellata, sp.nov. 2. Wax mould. 3. Portion of same,
x5. 4,5. Natural mould. 4. Anterior view. 5. Left valve.

Figs. 6-8. Arctica? equisulcata, sp.nov. 6. Dorsal view of natural mould.
7. Right valve of same. 8. Left valve, with part of shell preserved.
8a. Portion of same enlarged, x3.

Figs. 9 & 10. Trapezium trapezoidale (Romer). 9. Left valve. 10. Dorsal
surface of the two valves.

Figs. 11 & 12. Trapeziwm rectangulare, sp.nov. Internal moulds. 11. Left
valve. 12. Dorsal surface of the two valves.

Figs. 13 & 14. Corbis? Morisoni, sp.nov. 13. Right valve. 14. Anterior end.

Figs. 15-18. Martesia? rotunda (Sowerby). 15-17. Internal casts, x 2.
15. Dorsal view. 16. Right valve. 17. Anterior end. 18. Wax
mould of exterior of right valve, x 23.

Figs. 19 & 20. Cuspidaria caudata (Nilsson). Internal cast. 19. Left valve.
20. Dorsal surface.

1 F, BE. Schultze, ‘Report on Hexactinellida, Challenger Exped. (1887)
pp. 453-467.

232

404 THE MOLLUSCA OF THE CHALK ROCK. [ Aug. 1897...

DISCUSSION,

Dr. W. F. Hume congratulated the Author on the completion of
this detailed contribution to our knowledge of the Chalk Rock
fauna, and referred to the interest of the records of Chlamys and.
Arctica at this horizon. That the nodular condition characteristic
of this lithological feature had been formed at some depth was an
hypothesis now being generally accepted; but the Author, in dis-
cussing the question of the depth at which the deposit had been
formed, scarcely seemed to lay sufficient stress on the action of
currents, which to the speaker appeared of essential value in the
formation of the nodular rock. Analyses carried out recently show
that the glauconitic material is generally present only in small:
quantity, the carbonate of lime in most cases exceeding 90 per cent. ;
so that the higher bathymetric limit assigned by the Author appears.
to be the more probable. The repetition of a lower or Cenomanian
fauna in the Chalk Rock, to which the Author has again called —
attention, is one of great interest, and the beds containing these’
forms should be considered as the true upper limit of the Middle
Chalk, all the more arbitrary boundaries adopted having completely”
broken down.

Mr. W. Warraxne also spoke.

Quart.Journ.Geol.Soc Vol. LI. PlXXVII

Edwin Wilson, Cambridge

CHALK ROCK MOLLUSCA.

| Quart. Journ.Geol.Soc. Vol. LIP] XXVIII

Edwin Wilson,Cambridge.

CHALK ROCK MOLLUSCA.

. 7 hy as é

Mol 53: | AUGITE-DIORITES WITH MICROPEGMATITE. 405

29. On AveltE-DIoRITEs with MicRopEGMATITE tm SoUTHERN INDIA.
By THomas H. Hoxrtanp, Esq., A.R.C.S., F.G.S8., Officiating
Superintendent, Geological Survey of India. (Read May 26th,

1897.)
[Prats XXIX.]
ConTEntTs.

Page
Pe Morbo dthioiny 2.5.6 csectaare chenceane «eee eel aaatacause needed 405
II. Petrological Characters of the Rocks .............sscecscsceses 406
IIT. Chemical Composition of the Rocks...............scssescseseeces 408
IV. Explanation of the Structure of the Dyke-rocks ............ 409
V. Comparison with so-called Granophyric Gabbros............ 411
NEL cS untied ey” aceon ce van a tdorceekeae st conaredoeteieauice sats acaetoas es 414

I. Iyrropvuction.

Prior to the great outburst of Deccan trap at the close of the
Cretaceous period, there were two principal periods of volcanic
activity in Peninsular India. One of these is indicated by the
contemporaneous traps of the Dharwars—the oldest of our recognized
Transition systems—and the other by the lava-flows of the Cuddapah
system, whose precise position in the stratigraphical succession
remains, on account of the complete absence of fossils, still un-
determined. As a result of the great earth-movements which
affected the strata of Peninsular India previous to the deposition of
the Cuddapah system, the igneous rocks of Dharwar age have been
greatly metamorphosed, and in this respect they stand in striking
contrast to the Cuddapah traps, since the eruption of which the
Peninsula of India has been remarkably free from geological dis-
turbances. It is evidently in consequence of this remarkable
freedom, both from extreme changes of level and the crushing
effects of earth-movements, that rocks as old as the Cuddapahs
have their original delicate structures, and primary constituents so
susceptible as olivine and augite, preserved with striking freshness.

The numerous dykes of basic igneous rocks which break through
the ‘ pyroxene-granulites ’ and gneisses of the Madras Presidency,
and which, for reasons that need not now be stated, are regarded
as the dyke-representatives of the Cuddapah lava-flows,’ vary in
composition from very basic olivine-augite norites approaching
saxonites, through augite-norites, to augite-diorites with micro-
pegmatite. Detailed descriptions of these and the peculiar hemi-
erystalline and vitreous varieties, which form the selvages of the
larger masses, or occur as narrow apophyses, are published in the
Records of the Geological Survey of India (vol. xxx. pt. 1.1897). It
is only with the interesting features displayed by the rocks which I
have grouped under Prof. Cole’s very convenient term augite-
diorite that the present paper is intended to deal.

The augite-diorite dykes occur in various parts of the Madras

1 ‘Manual of the Geology of India,’ 2nd ed. (1893) p. 40.

406 MR. T. H. HOLLAND ON AUGITE-DIORITES WITH [Aug. 1897,

Presidency, but are particularly well-developed in the districts of
Chingelput and South Arcot, on the Coromandel coast, where they
break through the acid members of the ‘ pyroxene-granulite”
series, and are often traceable for many miles, showing their actual
contacts with the older crystallines, or projecting as Fine of black
hummocks through the alluvium and soil of the ‘ paddy ’ fields.

The facts revealed by the microscopic study of these Indian rocks
have, it seems to me, the most interesting bearing on the questions
raised by the distinguished petrographers who have examined the
well-known associations of micropegmatite with basic rocks near
Penmaenmawr,' in the Charnwood Forest,’ the Whin Sill,? the
Cheviot district,? Carrock Fell,’ Carlingford,’ and Skye.’

II. Perronogican CHARACTERS oF THE Rocks.

The central masses of the large dykes are tough, black, even-
grained rocks, in which the crystals seldom exceed 5 mm. in length.
The specific gravity is remarkably uniform, varying between 3:00
and 3:09. Towards the margins of the dykes the rocks are finer
in grain, while the selvages, so far as their microscopic characters:
are concerned, could not be distinguished from augite-andesites,
having a fine-grained, pilotaxitic, and sometimes distinctly hyalo-
pilitic groundmass, through which irregular, glomero-porphyritic
eroups of augite and plagioclase are scattered.

Mineral Composition—The rocks are composed essentially of
augite, plagioclase, and micropegmatite. Knstatite is often present.
in small quantities, forming the cores of the pyroxene-crystals.
Opaque, black iron-ores, hornblende, and biotite in small quantities,
and either wholly or in part secondary in origin, present a constant.
and peculiar relation to the augite and micropegmatite, the signi-
ficance of which is pointed out below.

more basic dykes associated with these rocks, and in which enstatite
is a prominent constituent, the consolidation of the plagioclase must:
have been completed invariably after that of the pyroxene, in the
augite-diorites now under consideration there is no such distinct
difference between the periods of the consolidation of these two
minerals. They are intergrown with a want of regularity which
indicates an average simultaneous crystallization, and this conclusion
is confirmed also by the intergrowths exhibited in the glomero-
porphyritic groups of augite- and plagioclase-phenocrysts in the
hemicrystalline varieties forming the selvages of the dykes,

1 J. A. Phillips, Quart. Journ. Geol. Soc. vol. xxxiii. (1877) p. 423; Waller,.
‘ Midland Naturalist,’ 1885, p. 4.

2 Hill & Bonney, Quart. “Journ. Geol. Soc. vol. xxxiv. (1878) p. 199.

3 Teall, Quart. Journ. Geol. Soc. vol. xl. (1884) p. 640.

4 Td. ‘ British Petrography ’ (1888), p. 272.

> Ibid. p. 179; Harker, Quart. Journ. Geol. Soc. vol. 1. (1894) p. 311-&
vol. li. (1895) p. 125.

6 Sollas, Trans. Roy. Irish Acad. vol. xxx. (1894) p. 477.

7 Harker, Quart. Journ. Geol. Soe. vol. lii. (1896) p. 320.

Vol. 53.] MICROPEGMATITE IN SOUTHERN INDIA. 407

The micropegmatite, however, is distinctly later in origin, being
never older than tlie ‘ water-clear’ outer margins of the felspar-
crystals. But although distinctly the last-formed original con-
stituent, there is no reason for regarding it as other than the
result of one continuous process, and the final stage in the consolida-
tion of the magma which gave rise to the rock.’

The order of the crystallization of the constituents is, then, the
following :—

(1) Augite and plagioclase together forming the main mass
of the rock, and
(2) Micropegmatite, playing the part of groundmass.

The augite is pale brown in colour, sometimes distinctly pleo-
chroic, frequently twinned according to the common law, and, so
far as its original microscopic characters are concerned, calls for
no further remark. An analysis of material carefully separated
from the dyke at the Seven Pagodas, Chingelput district, whose
bulk-analysis is given below, shows the close resemblance between
the monoclinic pyroxene of this rock and that of the petrologically
similar Whin Sill analysed by Mr. Teall.

if Li.

SOG is Be ele ince en ee 50:02 = 49-08
tek! CR aetna gene pene 561 5°46
Be Trae tito enact taadecectet cs 15°61 15°57
RUERMOR tee Stes etme aun ate trace 0°22
CaOe a eae Aes 14-84 15°34
i 8 Ree See eee 1201 11-66
INA OBES OW 2s eats om casita 0-96 1-24
Loss on ignition ..............- 0°76 0°81

99°81 99°33

I. Monoclinic pyroxene in augite-diorite dyke, Seven Pagodas, Uhingelput
district, Madras Presidency.

II. Monoclinic pyroxene from the Whin Sill, Teall, Quart. Journ. Geol.
Soe. vol. xl. (1884) p. 648.

The central portions of the plagioclase-crystals give the extinc-
tion-angles of varieties approaching labradorite in composition. But
as the margins of the crystals are approached the well-known zoning
by change of chemical composition is well displayed. The central
portions of the crystals are pale-brown in colour through innumerable
original inclusions, a feature which is also well shown by the
phenocrysts of the hemicrystalline varieties. But in the holo-
crystalline, coarser-grained types, the plagioclase-crystals become
paler in colour near the margins and finally ‘ water-clear’ in their
outermost zones.

The micropegmatite generally fills in the angles between the
felspars and pyroxenes, and is composed of the usual intergrowth of
quartz with felspar, which is sometimes microcline, but generally
plagioclase. When the intergrown felspar is plagioclase its

‘ The evidence, upon which the conclusion as to the primary origin of the
Micropegmatite is based, is detailed below and on p. 409.

408 MR. T. H. HOLLAND ON AUGITE-DIORITES witH [ Aug. 1897,

crystallographic continuity with an adjacent normal, and unques-
tionably original, plagioclase can generally be demonstrated between
crossed nicols. The quartz and felspar of the micropegmatite both
contain numerous colourless, or very pale-green, acicular crystals,
which, being thinner than the sections of doubly-refracting minerals
in which they lie, cannot be determined with certainty. On account
of the almost constant presence of these acicular crystals and on
account of the constantly ‘ water-clear,’ limpid appearance of the
quartz and felspar in which they lie, the patches of micropegmatite
can easily be detected in ordinary light.

As noticed by Teall in connexion with the Whin Sill,! the
coarseness of the micropegmatitic patches varies with that of the
remaining constituents of the rock, and in the finer-grained
varieties the separation of the constituents becomes less and less
pronounced, until the quartz- and felspar-individuals, becoming
narrower than the thickness of the section, are indistinguishable
one from another in polarized light, thus passing into the structure
to which Harker has given the name cryptographic.? This
interesting character strongly supports the conclusion that the
micropegmatite is primary in origin.

The minerals which are wholly, or in part, secondary in origin
are opaque iron-ores, hornblende, and biotite. In the larger number
of dykes these minerals are comparatively small in quantity, and are
almost always situated on the margins of the augite which abut
directly against the micropegmatite, while the faces of the same
mineral abutting directly against the ordinary plagioclase-crystals
are more often quite free of any such signs of secondary change.
The secondary changes in the augites are thus facilitated by proxi-
mity to the micropegmatite, and in the few dykes in which hydrous
decomposition has appreciably advanced these peculiar circumstances
are still more marked. In such cases the felspars of the micropeg-
matite itself have been completely decomposed and converted into
an aggregate of minute chlorite-flakes, sometimes clear green and
sometimes coloured by rusty stains. The felspars around the micro-
pegmatitic patches are at the same time kaolinized to varying
extents, accompanied by the deposition of secondary quartz in erys-
tallographic continuity with that forming part of the micropegmatite ;
while the augites are, on the faces exposed to the micropegmatite,
corroded by the formation of hornblende, biotite, and iron-ores (see
Pl. XXIX. fig. 1). The significance of these phenomena is indicated
farther on (p. 413).

III. Cuemicat Composition oF THE Rocks.

For the purposes of chemical analysis, I have selected the dyke
exposed near the rock-hewn Seven Pagodas, in the Chingelput
district, as an example of the well-crystallized types comparatively
free from enstatite; and the selvage of a dyke near Perumbakam, in
the South Arcot district, as the most typical of the fine-grained

1 Quart. Journ. Geol. Soc. vol. xl. (1884) pr. 644.
2 « Petrology for Students’ (1&95), p. 92.

Vol. 53.] MICROPEGMATITE IN SOUTHERN INDIA. 409

types approaching augite-andesite in structure. Sections of both
these rocks are figured in Pl. XXIX. figs. 1 & 3. For the analysis
of the rock from the Seven Pagodas I am indebted to Mr. P. Briihl,
Professor of Physics in the Civil Engineering College, Sibpur.

ee II. Augite-andesite. |

Micropegmatite. Hoeees, :
SER ieee sete ances 51°15 50-86
MEO soa5 fo coos cc eck oe 0-44 0°63
OE ee ssieds oaviaopin'a users 0-06 trace
PO nc 15-92 15°65
ee a er He 90
INO G05 ton nt oS we dbns 0:09 trace
A ss eww ase tees s 10-40 11°76
(LIE OSES Se Eee 6-48 6-03

Lo ee es ee Tal) 2:01 |
Td, he a 1-61 1:56

250 ei ee 0-11 0-20
99°66 99°55
PEE nie casec.ceessere: 3°19 301

Both these analyses recall the composition given by Mr. Teall for
the Whin Sill, with which these rocks agree so strikingly in petro-
logical characters." The comparatively high percentage of potash
among the alkalies indicates the probable presence of a potash-
felspar as a constituent of the micropegmatite, and this is confirmed
by the detection of microcline in several of the dykes.

If the silica, alumina, and alkalies due to the micropegmatite,
which possesses a silica-percentage near that of Bunsen’s ‘normal
trachytic magma’ (76°67 Si0,), were deducted from the bulk-analysis
of the rock, the remainder would agree fairly closely in composition
with the ‘normal pyroxenic magma’ to which Bunsen gave the
hypothetical composition :—Si0,, 48°47 ; Al,O,, 14°78 ; CaO, 11°87 ;
MgO, 6°89; FeO, 15°38; alkalies, 2°61. It is an interesting cir-
cumstance that the numerous associations of gabbro with granophyre
which have been recorded should so closely approach in composition
Bunsen’s hypothetical normal pyroxenic and normal trachytic
magmas, and the similar association of these two types on a micro-
scopic scale in the South Indian dykes suggests the derivation of
these two distinct rocks by segregative consolidation from an
originally common magma.

IV. ExpLansTION OF THE STRUCTURE OF THE Dykr-ROCKS.

As already pointed out, the augite-diorite dyke-rocks of Southern
India are composed principally of augite and plagioclase, with
subordinate quantities of micropegmatite. The relations of the

1 See Teall, Quart. Journ. Geol. Soe. vol. xl, (1884) p. 654.

410 MR. T. H. HOLLAND ON AUGITE-DIORITES wit [Aug. 1897,

augite and plagioclase show that these two constituents consolidated
approximately simultaneously, while there is no doubt that the
micropegmatite was formed subsequently. The principal question
to decide is whether the micropegmatite was formed—

(a) During the primary consolidation of the magma which was.
injected to form the dykes ;

(5) By secondary changes induced in the rock ;

(c) By subsequent intrusion of granophyric an into the
augite-plagioclase rock.

The complete absence of granitic intrusions, and for that matter
of intrusions of any sort, into the very large number of basic dykes-
which have been carefully examined in Southern India puts the third
consideration out of the question. The remarkable freshness of the
rocks—their escape from crushing movements, as well as their
freedom from the signs of subaerial hydration-—precludes the possi-
bility of explaining the presence of the micropegmatite as the result:
of secondary changes. But besides the removal of alternative
explanations by very complete and satisfactory negative evidence
in so large a number of instances in which these points of evidence:
have been tested, the first explanation offered—namely, that the
micropegmatite is primary in origin—is supported uniformly by

(1) The crystallographic continuity of its felspar with that of the
normal plagioclase of the rock.

(2) Its occurrence filling in the angles and spaces between the

augite and plagioclase, thus playing the part of groundmass; and

( (3) Its variation in coarseness of grain agreeing with that of the
remaining two constituents of the rock. In the centres of the
large dykes the separation of the quartz from felspar in the micro-
pegmatitic patches can easily be seen with low powers ; in the fine-
grained portions nearer the margins, and in the smaller dykes, the
intergrowth of these two minerals is on so minute a scale that
even with high powers their individualization is not evident.
Had the micropegmatite been introduced into the rock by subsequent-
intrusion, or had it been caused by secondary changes, such a
relation between its structure and that of the rock would have been
merely fortuitous, and therefore never an uniform rule.

The formation of the micropegmatite is, therefore, dependent
directly upon the processes by which consolidation of the magma
has been accomplished, and represents the final stage of that
consolidation.

The consolidation of the rock may thus be divided into two
distinct, though perfectly continuous, processes :—

(1) The crystallization of the augite and plagioclase, when make
up the principal mass of the rock, to form a strong framework.

(2) The formation of micropegmatite from the residual mother-
liquor filling the angular spaces and interstices in the framework of
augite and plagioclase.

As the crystallization of the mother-liquor filling in the inter-
crystal lacunae and their ramifying connexions would be attended
with the usual reduction in volume, and as the framework of augite:

—s

Vol. 53.] MICROPEGMATITE IN SOUTHERN INDIA. 4\1

and plagioclase would be sufficiently strong to prevent the collapse
of the rock under any but extreme pressure, the micropegmatitic
patches would be less compact than the rest of the rock; they
should in fact be miarolitic on a very small scale—to save words,
micromiarolitic. That this actually is the case is confirmed
by a very interesting feature displayed by all the rocks in which
hydrous decomposition has commenced. In these it is seen that
the decomposition has invariably developed around the micropegma-
titic patches, the felspars in the immediate neighbourhood of the
patches being kaolinized, the secondary biotite and hornblende
changed to chloritic products, and theiron-ores rusted. The greatest
change of all has been effected in the felspars which originally
formed part of the micropegmatite ; these have, as a rule, completely
lost their original characters, and their places are now occupied by
chloritic products, which have been manufactured from their
remains with the aid of iron, magnesia, and other compounds
derived from the adjoining biotite and iron-ores. Not the least
interesting among the changes brought about by the introduction
of water is the formation, in the adjoining kaolinized felspars, of
secondary quartz in crystallographic continuity with that forming
an original constituent of the micropegmatite, and thus becoming
a secondary extension of the structure. These unmistakable signs
of hydrous decomposition limited to the neighbourhood of the micro-
pegmatite show that the water is distributed through the rock by
this means. The intercommunicating lacunz once occupied by the
residual mother-liquor, and subsequently filled loosely by the quartz
and felspar into which it crystallized, now evidently form a most
intricate arterial system for water-communication.

V. CoMPARISON WITH SO-CALLED GRANOPHYRIC GABBROS.

In his interesting memoir ‘On the Relation of the Granite to
the Gabbro of Barnavave, Carlingford,’ Prof. Sollas has brought
together a great assemblage of facts to show that the micropeg-
matite in the gabbro had been produced by minute intrusions of
‘ granophyric’ material in a state of great fluidity, subsequent to
the consolidation and even jointing of the older gabbro. In com-
paring the Carlingford case with the similar instances of micro-
pegmatite occurring in basic rocks in Great Britain, Prof. Sollas
pointed out the association of granophyric massive rocks with the
well-known enstatite-diorite of Penmaenmawr and with the gabbro
(augite-diorite) of Carrock Fell. For want of evidence, however,
concerning the presence of granophyric intrusions in connexion with
the Whin Sill, Prof. Sollas was unable to extend his explanation to
that well-known instance; at the same time he remarked that
‘till minute veins or dykes of granophyre have been specially
searched for in this dyke without success, it will be impossible, in
the light of our recent observations, not to feel some suspicion as
to the real nature of the granophyric inclusions.’ !

' Trans. Roy. Irish Acad. vol. xxx. (1894) p. 477.

412 MR. T, H. HOLLAND ON AUGITE-DIORITES WITH | Aug. 1897,

The Madras dykes afford a fairly complete answer to Prof. Sollas’s
difficulty. The cases of augite-diorite dykes containing micro-
pegmatite, which have been carefully examined by several members
of the Geological Survey of India, are not one or two, but
several scores; and not a single instance has been recorded of a
dyke crossed by a later igneous intrusion of any sort, granitic or
otherwise. The basic dykes, as recently remarked by my colleague
Mr. C. 8. Middlemiss, who, with Mr. F. H. Smith and myself, has
during the last season kept this question specially in view, ‘ show
nothing to suggest a veining by any other rock. They are well-
defined, weather out into well-marked boulders, exfoliate concen-
trically, ring hike metal under the hammer, and completely suggest
a homogeneous composition.’ It would, therefore, be quite contrary
to the evidence to consider the micropegmatite to be the result of a
later and separate intrusion, while for regarding it as derived from
the magma which gave rise to the augite and plagioclase there is
abundant evidence, both positive and negative.

In extending his explanation of the relations between the granite
and gabbro of Carlingford to the peculiar structure of the Whin Sill,
Prof. Sollas has given us a precedent for, per contra, extending
the explanation which accounts for the intimate association on a
microscopic scale of granophyric material with augite-diorite to the
frequent instances which have been recorded of larger masses of
granophyric acid rocks occurring in intimate association with basic
masses. ‘The association of pyroxene-diorite with granophyre in
such well-known instances as the Stanner Rock, at Penmaenmawr,
Carrock Fell, Carlingford, and the Western Isles of Scotland are
sufficiently numerous within the limited area of the British Isles to
suggest some sort of genetic relationship between two rocks that
are found so often together, and with such a constancy in the
peculiarities of their relations one to the other.

In the case of the Madras dykes I have attempted to show that
the structure of the rocks indicates the formation of a strong
framework of augite and plagioclase before the consolidation of the
more acid residual mother-liquor in the interstices. Such an
occurrence would be possible where, as is the case with these rocks,
the augite and plagioclase together far exceed in quantity the
micropegmatite, and where also the pressure to be withstood by
the framework so formed is limited. But where the basic minerals
are in subordinate quantity, and where, as would most certainly be
the case in large bosses, the pressure is much greater, it would be
only natural to expect that the formation of a loose framework of
the older minerals would be impossible, and there would as a
consequence be a more complete separation into distinct masses of
the two divisions of the magma, the first-formed giving rise to
an augite-diorite, while the second phase of consolidation would be
represented by the formation of an acid rock. In his detailed
examination of the gabbro and granophyre of Carrock Fell, Harker
approaches a similar conclusion in stating that the interval between
the consolidation of the two rocks was probably a short one, the

Vol. 53. | MICROPHGMATITE IN SOUTHERN INDIA. 413:

acid magma being intruded among rocks already hot.’ Such a
conclusion accounts for the coarseness of grain which has been so
frequently, almost invariably, observed in the granophyric rocks at
the junctions with their basic associates.”

But still more interesting are the secondary changes induced in
the gabbro at its junction with the granophyre. Harker has noticed
that near the granophyre the augites of the gabbros (augite-diorite)
are largely replaced by green hornblende, and biotite sometimes
occurs.*- I have already referred to precisely similar changes in the
augites of the Madras dykes where they come into contact with the
micropegmatite, while the same augite-crystal where it abuts cleanly
againsta plagioclase is often quite fresh and unchanged (supra, p. 408)..
The explanation of these phenomena which agrees most nearly
with the facts seems to me to be somewhat as follows:—The
water originally contained in the molten magma would become,
by the separation of the anhydrous minerals, augite and plagioclase,
excluded to the final stages of consolidation, before the completion
of which there must have been a more perfect condition of what
has been frequently described as aquo-igneous fusion. The separa-
tion of the silica and alumino-alkaline silicate, as quartz and
felspar respectively, from this aquo-igneous melt would leave the
miarolitic channels filled with heated vapours, which would be
free to attack the susceptible ferromagnesian silicate, and bring”
about the excretion of magnetite and formation of biotite by altera-
tion of the highly ferriferous, and almost non-aluminous, augite.*

Although more limited in extent, the secondary changes shown by
the augites where they come into contact with the micropegmatite
are precisely similar in kind to those described by Prof. Sollas ’ as
brought about by the action of the granophyre on the pyroxenic
xenocrysts obtained from the gabbro of Barnavave—the assumption:
of a green colour, the excretion of magnetite, and the formation of
biotite and hornblende referred to by Prof. Sollas as results of
the transformation of diallage-xenocrysts, being phenomena, con-
stantly observed wherever the augite-crystals come into contact
with micropegmatite in the Madras dykes. Although these facts
suggest the likelihood of a similarity of physical conditions
during the consolidation of the Barnavave granophyre and the
micropegmatite in the Madras basic dykes, there is no escaping the
conclusion that in the latter instance the acid material was formed
after, and in direct succession to, the consolidation of the augite and
felspar, and was thus formed at probably a lower temperature.
If this conclusion be the correct one, it follows that the change of

? Quart. Journ. Geol. Soc. vol. li. (1895) p. 133.

2 Ibid. p. 148.

* Ibid. pp. 133, 134, & 135.

* That water existed in the original molten material is more than likely, and
that its presence would result in a suspension of consolidation will, in view of
the researches which all point to the conclusion first indicated by Scheerer in.
1846, be now generally conceded.

5 Trans. Roy. Irish Acad. vol. xxx. (1894) pp. 493, 494,

Al4 MR. T. H. HOLLAND ON AUGITE-DIORITES witH [ Aug. 1897,

augite to hornblende and biotite with concomitant separation of
magnetite does not necessarily indicate that the augite-diorite has
‘been altered by a subsequent and distinct igneous intrusion at a
high temperature,

If the separation of the acid from the basic portions of a magma
on a large scale, such as may have occurred in the instances quoted
above, be really analogous to that which has taken place on a
microscopic scale in the Whin Sill and the Madras dykes, we should
naturally expect to find that the acid rock is later than its basic
-associate in completing its consolidation. At the same time, the
close agreement in the ages of the two rocks might very well give
rise to apparently contradictory phenomena along their junction-
lines (especially if earth-movements disturbed them during, or sub-
sequent to, consolidation), and so produce isolation of injected por-
‘tions of the granophyre, or even local re-fusion of the rocks from the
heat produced by mechanical movements.

In the minute intercrystal channels and lacune filled with micro-
miarolitic micropegmatite in the Madras augite-diorite, we have the
equivalents of what the older geologists understood by the term
‘contemporaneous veins,’ veins which, though formed after suffi-
cient consolidation of the rock in which they occur, are yet derived
from the same magma and form part of one geological unit.
Although there is no doubt that the augite and plagioclase were
separated before the micropegmatite, the two groups of minerals
have been separated from the same magma, and are as much ‘ con-
temporaneous ’ as are two twins, which for obvious reasons are not
born simultaneously. Such was the view taken by Waller in
describing the augitic acid veins penetrating the enstatite-
diorite of Penmaenmawr, and such apparently was the idea in
Macculloch’s mind when, in discussing the difficulties of settling the
relative ages of the similar rocks in the Western Isles of Scotland,
he concluded that the ‘trap’ and the ‘syenite’ had a common
origin.! Haughton, in describing the granite of Barnavave, has also
classed the granophyric veins penetrating the gabbros as ‘con-
‘temporaneous. ”

VI. Summary.

In the Madras Presidency the pyroxene-granulites and the
ordinary gneisses are penetrated by a very large number of basic
dykes, which are regarded as the underground representatives of the
Cuddapah lava-flows. Since the intrusion of these rocks the Indian
peninsula has been remarkably free from earth-movements, and the
structures of the dykes are beautifully preserved.

Many of these rocks are augite-diorite with micropegmatite.
‘They consist mainly of augite, approaching hedenbergite, and
plagioclase, approaching labradorite in composition. The crystal-
lization of these two minerals has been approximately simultaneous,

2 ‘Description of the Western Isles of Scotland, vol. i. (1819) p. 363,

-vol, ii. pp. 57 & 345.
2 See also Sollas, Trans. Roy. Irish Acad. vol. xxx. (1894) p. 478.

Vol. 53.] MICROPEGMATITE IN SOUTHERN INDIA. 415

constituting the first phase in the consolidation of the magma,
while micropegmatite—subsequently formed and representing the
final stage in the consolidation of the magma—fills in the angles
between the augite and plagioclase, and so plays the part of ground-
mass.

The augite and plagioclase being in excess, their simultaneous
separation from the magma resulted in the production of a strong
solid framework, the angles and interstices of which were filled in
with more acid mother-liquor, which ultimately gave rise to the
micropegmatite. As the crystallization of the mother-liquor filling
these intercrystal lacune and their ramifying connexions would be
attended with the usual reduction in volume due to crystallization,
and as the framework of augite and plagioclase previously formed
would be strong enough to resist any but extreme pressure, the
micropegmatite would be less compact than the rest of the rock, and
would be miarolitic on a small scale (micromiarolitic). Hence
the lacunz and channels, loosely filled with micropegmatite, would
form an intricate arterial system throughout the rock for, first of all,
the passage of the liberated hot vapours, and finally for water. As
a consequence of this fact, we find that the portions of the augites
abutting directly against the micropegmatite are almost invariably
attacked in the freshest of the rocks, while in those wherein hydrous
decomposition has appreciably commenced the micropegmatitic
patches are always the centres of very marked changes, the felspars
in their immediate neighbourhood being kaolinized, the biotites
converted into chloritic products, and the iron-ores rusted.

In these augite-diorite dykes the coarseness of the micropegmatite
varies with that of the other constituents ; in the coarser-grained
varieties the quartz and felspars are easily distinguished between
crossed nicols, while in the finer-grained varieties, forming the
margins of large masses or constituting smaller dykes, the inter-
growth of the constituents of the micropegmatite is as minute as
that in the structure to which Harker has given the name ‘ crypto-
graphic. The felspar of the micropegmatite is sometimes micro-
cline, but more often plagioclase; when the latter, it is generally in
crystallographic continuity with the outer zone of an adjoining and
unquestionably original plagioclase. For these reasons, principally,
the micropegmatite is regarded as primary in origin. The rocks
being, as a rule, remarkably fresh and unaltered, there is no reason
for considering the micropegmatite to be secondary in origin. As
the numerous augite-diorite dykes are never found to be crossed
by veins of granite or by subsequent intrusions of any sort, the
explanation applied by Prof. Sollas to the ‘ granophyric gabbro’ of
Carlingford, and suggested by the same author for similar cases of
augite-diorites with micropegmatite in Great Britain, is not applic-
able to any of the numerous dykes which have been very carefully
examined in Southern India.

Where the augite and plagioclase far exceed the micropegmatite
in quantity, and where the pressure is not too great, the formation
of a strong solid framework by the simultaneous crystallization of

416 MR. T. H. HOLLAND ON AUGITE-DIORItES with [ Aug. 1897,

these two minerals would naturally precede the crystallization of
the more acid residual mother-liquor. But in large boss-like
masses, where the pressure is greater, and especially in cases where
the basic material is not in great excess, such a framework would
be impossible, and as a consequence there would be a more complete
separation into distinct masses of the two divisions of the magma,
the first crystallized giving rise to an augite-diorite, while the
second phase of consolidation would be represented by the formation
of an acid rock.

The suggestion is thus offered that the gabbros (augite-diorites)
are genetically related to the granites (granophyres) with which
they are found associated in the British instances quoted in the
Introduction (p. 406). If this be so, we should expect, as the micro-
pegmatite is consolidated after the augite and plagioclase in the dyke-
rocks, so the granophyric rock will, as a rule, be later than its basic
associate in completing its crystallization. We should expect,
consequently, to find evidence—and such has been given by Harker
and others—to show that the basic rock was still hot when the
acid rock consolidated, veins or junctions of the latter with the
former being coarse in grain. At the same time, the periods of
consolidation of the two rocks are sufficiently close to account for
apparently contradictory phenomena along their line of junction—
veins of the acid rock in the basic might be converted into isolated
inclusions by earth-movements, while local re-fusion might be
caused by the heat resulting frém mechanical movements.!

The micropegmatite forming, as described, an intricate system of
veins running through the framework of previously-crystallized
augite and plagioclase, represents what the older geologists under-
stood by ‘ contemporaneous veins,’ veins which, though formed after
sufficient consolidation of the rock penetrated by them, are yet derived
from the same magma, and form part of one geological unit.

The separation of anhydrous minerals during the early stages of
consolidation would result in the exclusion of the water originally
contained in the magma to the mother-liquor. This residual, and
generally more acid, mother-liquor would thus be in a state of more
perfect aquo-igneous fusion; and hence, although the temperature
may be below that at which the first portions separated, when the
proportion of water in the magma was lower, it may still be above
that at which the more aqueous residue would consolidate, and as a
result the ‘ contemporaneous veins’ may be as coarse as, and often
coarser than, the rocks which they penetrate.

1 In comparing the intimate admixture of micropegmatite and augite-diorite
on a microscopic scale with associations of the same rocks in large masses, it is:
interesting to observe that the changes suffered by the augite, where it abuts:
directly against the micropegmatite, are precisely similar to those noticed by
Harker in the augite of the Carrock Fell gabbro (augite-diorite) at its junction
with the granophyric rock, while Sollas has described similar changes in the
dialiage which occurs as xenocrysts in the Carlingford granite (granophyre, in
the modified sense suggested by Rosenbusch).

aaiilie

Valis3.| MICROPEGMATITE IN SOUTHERN INDIA. 417

EXPLANATION OF PLATE XXIX.

Fig. 1. Augite-diorite with micropegmatite. Large dvke crossing the gneiss.
Seven Pagodas, Chingelput district. x 48 . The augite and plagio-
clase make up the main mass of the minerals included within the
field. Where the augite abuts directly against the water-clear
micropegmatite, as in the centre and lower parts of the field, green
hornblende, brown biotite, and opaque magnetite are formed, while

the edges of the augite meeting the plagioclase are generally quite
unaltered.

Fig. 2. A finer-grained variety of the same rock occurring as a narrow dyke
near Nemeli, South Arcot district. The micropegmatite, as well as
the augite and plagioclase, is finer in grain and sometimes almost
cryptographic. This rock shows the intergrowths of augite and
plagioclase to indicate an average simultaneous crystallization of the
two minerals. x42,

Fig. 3. Augite-andesite, the hemicrystalline selvage of an augite-diorite dyke
near Perumbakam, South Arcot district. The glomero-porphyritic
groups of augite and plagioclase show these two minerals crystallizing
at about the same time, being intimately intergrown although they are
in a free matrix. The presence of vitreous material in this matrix
could not be demonstrated. x22.

Fig. 4. Augite-diorite with micropegmatite. A dyke in biotite-gneiss, Jauli-
kerai, Hosurtaluk, Salem district. The hydrous decomposition which
has commenced in this rock has manifested itself most markedly in,
and immediately around, the micropegmatite, the felspars of which
have been converted into an aggregation of minute chloritic flakes,
while the plagioclase in the immediate neighbourhood has been
kaolinized, and secondary quartz has been deposited in crystallographic
continuity with that forming part of the micropegmatite. This rock
is an example also of the-types in which enstatite forms a considerable
portion of the pyroxenic constituent, and which form a link with
certain norites described in a paper in the Records of the Geological
Survey of India (vol. xxx). x2,

Fig. 5. Portion of rock shown in fig. 4, seen in polarized light, so as to show
the interstitial micropegmatite. x 5.

Fig. 6. Portion of rock shown in fig. 1, seen in polarized light. x ae

Discussion.

Gen. McManon said that he had listened to the paper with great
interest, and looked forward to studying it in print. He thought
that the micropegmatitic structure arose in different ways in different
rocks, and that one explanation was not true for all cases. A
difficulty in holding that the structure was formed during the
primary consolidation of the rock arose from the fact mentioned by
the Author that the micropegmatitic portion of his rock altered the
pyroxenic minerals in contact with it. The Author spoke of heat
being generated in igneous masses by mechanical motion. Might
not this superinduced heat account for the formation of a micro-
pegmatitic structure? His observations had led him to believe that
the initial stage of remelting resulted, in some cases, in the
separation of free silica from felspars in the way seen in micro-
pegmatite.

Os. G. 8. No. 211. 2¥

418 MR. T. H. HOLLAND ON AUGITEH-DIORITES witH [Aug. 1897,

Prof. G. A. J. Coz observed that, while the dyke-like and sheet-
like masses of Madras and the Whin Sill of England, taken alone,
would certainly seem to support the view of differentiation of one
original magma, yet the matter must be judged by comparison with
areas which the Author has himself quoted. The speaker had
recently returned from Siieve Gallien, in South-eastern Londonderry,
where a granite, probably of Lower Old Red Sandstone age, has
invaded a volcanic and plutonic basic series, probably of Arenig
‘age. The phenomena of the junction-surfaces, and of the smaller
veins, repeat those described by Sollas, Harker, and others;
and the most extensive intermingling appears to have gone
on. Eyen the ferromagnesian constituents of the Slieve Gallion
granite may possibly result from the process of absorption. Hence
the intimate intermixtures, so well represented by the Madras
dykes, may arise from the joint mtrusion of materials already
well worked together and intermingled in the main mass lower
down.

Mr. W. W. Warts, after ascertaining that the previous speaker was
inclined to regard the biotite and hornblende of the Slieve Gallion |
granite as having been derived from a basic rock, pointed out that in
the rocks described by Harker from Skye the hornblende derived from
the augite of gabbro was quite distinguishable from tbe indigenous
hornblende of the granophyre. It was therefore certain that some
of the ferromagnesian minerals in granitic rocks were original, and
not derived at the expense of basic rocks.

Mr. Rurtey agreed with a previous speaker in thinking that the
Author was probably right in his conclusion that the micropegmatitic
matter was not of secondary origin, but doubted whether ‘ augite-
diorite’ was a perfectly satisfactory name to apply to a rock such as
that described. The diagram did not indicate a truly ophitic
structure, although it showed an approximation to it.

Rev. J. F. Braker asked whether in this particular case the Author
had definitely proved to his own satisfaction what were the actual
mineral constituents of the ‘ micropegmatite.’ If one of them was
optically continuous with a plagioclase, and there were also ortho-
clase and quartz, this would make three minerals; but he had not
been able to gather from the reading of the paper anything definite
on the question. He also enquired why the optical continuity
of part of the micropegmatite with the neighbouring plagioclase
proved it to be of the same general age, when similar accretions
were found round quartz-grains which meanwhile had been rolled
on the sea-shore.

Mr. J. J. H. Teatt and Mr. P. N. Darra also spoke.

Prof. Jupp stated that he had been in communication with
Prof. Sollas, who unfortunately was not able to attend and take
part in the discussion of this paper. Prof. Sollas, from the perusal
of the abstract and an examination of a slide of the Madras rock
forwarded to him, had been able to suppiy the following contribution
to the discussion, which, by the permission of the President, was
read :—

Quart. Journ.Geol.Soc Vol.LII.Pl XXIX.

THH.& MP.P.del.
M.-P. Parker lith.

Mintern Bros. imp.

MICROPEGMATITIC AUGITE-DIORITES
FROM SOUTHERN INDIA.

Vv

aioe Un
i yeh

+ 7
Ries,
‘ A

‘ bs

ip
a

Vol. 53.] MICROPEGMATITE IN SOUTHERN INDIA. 419

‘ As regards the primary origin of micropegmatite in basic rocks,
I would prefer to wait for further information before committing
myself. As against it, I note the alteration in adjoining minerals
which seems to be usually associated with the presence of micro-
pegmatite. This alteration is very marked in the augite of the
slide sent to me. The crystallographic continuity of the orthoclase
with the plagioclase proves nothing, except that these two kinds of
felspars are sufficiently isomorphous for the growth of the one
to follow on the lines of the other: as well might one argue
that the quartz enlargements of quartz-grains in a sandstone-rock
were primary, because they are in crystallographic continuity.

‘The co-variation in coarseness of grain simply indicates to my
mind that where druses exist there is room for the growth of large
crystals, and that the size of the crystals will bear some proportion
to the size of the druses. We see this in the druses of the Mourne
Mountains granite, and I have frequently observed in basalts and
dolerites structures in the immediate neighbourhood of cavities
which are now filled with large zeolitic crystals. The interstitial
character of the micropegmatite does not seem to me an argument
of much force.

‘The strongest argument to my mind against the secondary
origin of the micropegmatite is the existence of druses which it
postulates ; and itis this which leads me to a suspense of judgment.

‘As regards Barnavave, I take up a decided position, at least as
regards the so-called contemporaneous veins. They are not only
easy to trace into connexion with the great granitic masses of the
district, but they include clastic fragments of the gabbro and of its
constituent minerals. If a rock injected in a fluid state into
another previously consolidated can be called contemporaneous
with the rock it penetrates, the Author’s argument may possibly
hold, but I maintain that to apply the word contemporaneous
in this case 1s a misuse of terms.

‘As regards the Madras dykes, the absence of exposed acid rocks
is negative evidence solely; there is probably acid rock in every
igneous district; but it does not always come to the surface: I
quite agree with the Author that his supposed case (6) will not
hold.’

Prof. Judd added that he felt sure that the Author would be
greatly gratified to find that his views had met with the support of
Mr. Teall, Mr. Rutley, and other speakers that evening. In adopting
a name for the rock, the Author stated in the paper that he followed
Prof. Cole. It would be seen that from some of the admitted
facts the Author of the paper and Prof. Sollas drew deductions of
an exactly opposite character. With respect to the use of the term
‘contemporaneous veins, Mr. Holland maintained that the old
geologists who first employed the term were justified in using it in
cases where, though there must evidently have been a succession in
time between the formation of two kinds of igneous rock, yet both
were comprised within the same general period of eruption.

ZEEE

420 MR. E, P. RICHARDS ON THE GRAVELS AND [ Aug. 1897,

30. The Gravets and AssocrateD Deposits at Newpury. By
E. Percy Ricuarps, Esq., F.G.8. (Read May 12th, 1897.)

[Puatr XXX. ]
ContTEntTs.

§ 1. Introduction and Remarks on the General Geology of
GWG TVESERTCES oc" cans saeaansi enc atacees aoeeerecngaee ee eee 420
S'2) “he (Pre=Glacial Drritt | oscic. a's aca ceedes cee tance ee 420
§ 3. The Glacial (?) or Donnington Gravel .............002e000+ 422
§ 4. The Upper River-gravel or Terrace-gravel ............... 425
§ 5. The Lower River- gravel ee, ne ere te ee Bos 50 427
§ 6. The Neolithic Lake Series and Recent Deposits «0s. 430
Append ye. oid ora aaat oaseeseoesani ner tec asnanees asta 433
Nependi Ul 13.0100 SON ote hnecanctan te sone: ck ee eae 434

§ 1. Iyrropvcrion anp Remarks on THE GENERAL GEOLOGY OF THE
Disrricr.'

Tur observations recorded here were taken during the progress of
the main-drainage works at Newbury in 1894. Pressure of work
greatly curtailed my opportunities; nevertheless I trust that my
notes, though not of so much value as I could wish, will be of use
to geologists who are systematically studying our drifts and other
gravel-deposits.

The strata which I have examined may be apportioned into four
groups, as follows :—

(1) Pre-Glacial Southern Drift.

(2) Glacial (?) Drift.

(3) A lower and an upper Paleolithic River-gravel.
(4) Neolithic peat, loam, and shell-marl.

The Kennet Valley at Newbury is about 2 miles wide, broad and
fertile, with fiat water-meadows over the peat, stretches of cornland
and firm pasture upon the river-gravel terraces, while woods clothe
the low parallel hills which continuously enclose the valley.

River-gravels rest upon the Chalk-with-flints in the middle of
the valley at Newbury; but a few miles down stream both the
valley and the hills are formed in Eocene strata.”

§ 2. Tur Pre-Guacrat Drirr.

The first-mentioned gravel in the above list occurs in wide
regular layers over the Tertiary rocks in the district, and produces
the heathy commons, on each side of the valley, occupying an
average level of 440 feet above O.D. This gravel was said to be
probably ‘Southern Drift’ by the late Sir Joseph Prestwich, in his

1 See Note I. in Appendix L., p. 433.

2 As well seen in some sections shown to me by Mr. Fidler, of Newbury,
published, I think, in the ‘ Engineer,’ in relation to a proposed water-supply of
London by draining the Kennet Valley, and forming a lake from Aldermaston
to Thatcham ; wells and borings were recorded. See also Prestwich’s Map of
the Pre- Glacial Drift-beds of the Thames Basin, Quart. Journ, Geol. Soe,
vol. xlvi. (1890) pl. viii.

Vol. 53.] ASSOCIATED DEPOSITS AT NEWBURY. 421

‘Westleton’ papers." The following section, from a gravel-pit on
Greenham Common, south of Newbury, at 401 feet above O.D., is
typical of this gravel :—
Feet.
Peaty soil; the surface of the gravel beneath is much bleached... 1
Flint gravel, with a brown clay-and-sand matrix Samal

BEMAMENGUL) saunas rsve.- oe dea soePigacdeneh «cabs ciemede ate eatnes etre tale
70 °/, brown subangular flints, averaging 3 inches in diameter.. | 6
22 °/, subangular flints, brown inside, white outside, and less es
wolled/than the fornier:./6..0 .0/4es-/scvecslcahecseteseticscmcen | posed.
8 °/, perfectly rounded, small flints, stained throughout red,
purple; black, browns and girays Madesteas. ot ta~ sn dee ode on -Badeaetede )

The well-rounded pebbles are all very small, and much decom-
posed externally ; a few small subangular ‘sarsens’ of fine, cold-
grey, compact sandstone or quartzite, as well as fragments of chert,
were present; the surface of this gravel is much bleached. On
Snelsmore Common, north-west of Newbury, the following section
of a similar gravel was exposed, capping the Tertiaries at a level
ranging from 429 to 483 feet above O.D. :—

Feet
LURTIU CTL, 308 ees balm ee: ek Scan a ee See ve oe See ee 1
Flint-gravel in clay-and-sand matrix, with greyish intercalation |
a NN gmn ee oe ee oat cs Ree Ss Sache in einoiasboinn temp ad apelssnsdnasaa |
38 °/, pebbles: G2 ©), sunaneanar. == LOO) ca. cqecccancceseo.+-hedesan ‘ 6
SU Ween peOWwO: MIMiS 0 | oN cosa paste stiweectienencoereedseed { @X-
45 07° flints voloured black =o NOOR Reh S athe | posed,
o)/, smallsubanoular sarsenstomes: )) .......2..c-c0s---seeensesevdeu's )

An entire absence apparently of white quartz-pebbles, of green-
coated flints, gritstones, and Triassic pebbles.

As the Greensand does not reach the surface between the pre-
Glacial southern watershed and Snelsmore Common, we can under-
stand the scarcity of Greensand débris, as previously pointed out,
in reference to other sections, by the late Sir Joseph Prestwich.’

The most important points to be considered in determining the
age of this gravel are the levels, the entire absence of quartz-pebbles,
green-coated flints, and Triassic and quartzite-pebbles; also its
extent and mode of occurrence. The consideration of these points,
I think, fully warrants me in regarding it as ‘ pre-Glacial Southern
Drift.’

No bones or fossils of any kind have ever been found in this
gravel, to my knowledge. The exposed situation would facilitate
their removal by the infiltration of rain, if they had not been
previously destroyed by the strong water-action which arranged the
heavy débris.

At the borders of the commons this drift sometimes appears to
trail off into a reddish gravel, clearly shown as part of the Southern
Drift, in section AB (Pl. XXX), below the 400-foot level, com-
mencing at the Workhouse. This I have not closely examined; but
it appears to have resulted from the slipping down of the truncated
edge of the sheet of Southern Drift towards the valleys, and its
subsequent commingling with rainwash, and possibly with other
gravels of Glacial age.

1 Quart. Journ. Geol. Soc. vol. xlvi. (1890) p. 142. 2 Ibid. p. 162.

422 MR. E. P. RICHARDS ON THE GRAVELS AND [ Aug. 1897,

§ 3. Tur Gractat(?) or Donnineton GRAVEL.

The next distinct gravel upon the south side of the valley at
Newbury is the ‘Terrace-gravel’ (3); its upper surface is about
260 feet above O.D.

On the north side of the town, however, there is a deposit of
loam and gravel, occupying in section AB almost the same level
as the terrace-gravel does on the south side of AB, but rising
considerably above the terrace-gravel at Donnington Square, and
extending just over the 300-foot contour on the Bath Road, as
against 260 feet in the terrace-gravel.

This gravel and my ‘ Lower River-gravel’ have been marked on
Mr. Bennett's section through Newbury (now in the Town Hall at
Newbury) as ‘ Reading Beds.’ But this I find to be incorrect ; for
in the section of a well in Greenham Park, 440 feet above O.D., the
Chalk was reached at 217 feet above O.D., and the lowest layers of
the Reading Beds consisted of hard, dark-green sands, with a few
included layers of flints, succeeded by other green sands and dark
clays. Following the long section AB, it will be seen that these
are entirely wanting from the Great Western Railway to Don-
nington Square. A green sand forms the base of the terrace-
gravel, skirted by the railway on the south side of the river, and
. this may belong to the Reading Beds; but north of this the river-
gravels and the Donnington Glacial Drift rest immediately upon the
Chalk-with-flints.

Section of a Well in Greenham Park : 440 feet above OD.

=
he

12 Gravel and loam (Southern Drift).
Brown loam.
Brown sand, with water.
Brown loam.
Blue clay.
Black pebbles.
Blue sand, little water.
Dead-blue sand.
Hard dark stone.
Dark-grey sand.
Blue sandy clay.
London Clay.
Black pebbles.
Black sandy clay ; water at base.
Coloured sand and clay.
Coloured sand.
Light, sbarp, brown sand, with water.
Coloured clay and sand.
Mottled clay..
Green sand and water. °
Black clay.
Hard dark-green sand.
Flints.
‘Hard dark-green sand and flints.
Chalk reached, 217 feet O.D.

fom

‘spoq Joyssvq

—

DO Ore OUP eH ST © Hb
SSSSSSSSSSMMASSSONSHMSSSSOS

= ieee

‘speq Sulpveyy

“1 COR CO 5100 Ob

bo

Se Se eee Se

is)
iN)
ise)
(=)

Rael. 53°] ASSOCIATED DEPOSITS AT NEWBURY. 425

The presence of waterworn sarsens ' in both the river-gravel and
the Donnington gravel is another proof that these are not the
Reading Beds. -

Fig. 1 is a section through the Donnington gravels, near Don-

nington Square (road-surface 277 feet above O.D.), where the
best exposure occurred.

Fig. 1.—Section in the Donnington Glacial (?) Drift, near Donnington
Square. (No. 4 in the Map, Pl. XXX.)

Made ground and macadam.

Fine brown loam, 50 © 9 quartzose sand and 50°

= =< — = SS = . - . .
So SSS SS : tenacious clay, laminated, and with occasional

———— ==j faint traces of carbonaceous matter.
= == SSS

Coarse, roughly bedded sandy flint-gravel, some-
times with dark clay-matrix. About 85 "9
brown flints (some of which are bleached),
10/9 of various colours, and 59/9 greyish-
brown subangular sarsens, varying in dimen-
sions from small fragments up to 3 feet in
longest diameter, the largest being near the
base of the gravel. A few grits and sarsen-
pebvbles also occur. Of the flints 60/5 are
subangular and 409/9 rolled pebbles. Large

black, white-coated nodules at the base of the
gravel. Green-coated flints are very rare.

15 feet. |

2 feet Chalk-with-flints,

exposed “TW / eA al as
“i ie oe ae ra

[Vertical scale: 4 inch=1 foot. |

I obtained one fragment of bone in this gravel, which Mr. E. 'T.
Newton, F.R.S., has referred to Bison or Bos primigenius.

A cutting on the Lambourne Railway, through the watershed
separating the valleys of the Kennet and Lambourne, and at a little
higher level than fig. 1, shows the same loam and gravel resting

1 Note II. in Appendix L., p. 433.

424 MR. E. P. RICHARDS ON THE GRAVELS AND [ Aug. 1897,

upon an eroded surface of London Clay (fig. 2). During the rail-
way-operations remains of Hlephas primigenius were found very pear
this section, and they must presumably have occurred in this gravel.

Fig. 2.—Section in the Lambourne Railway-cutting.

2 feet. Grayelly soil.

Fine flint-gravel, same composition as grayel

1 foot. : 5 : below.

Fine reddish-yellow clay-and-sand loam, as in

2 feet. F fig. 1 (p. 423).

‘J4°:| Fine reddish, clayey flint-gravel, composed of
90 9/9 brown flints, 5 °/p black, white, and pale
coloured flints, and 5 4/9 small, slabby, lght-
coloured sarsens. Of the fiints 95 9/9 are sub-
angular, 5 99 rounded pebbles. ‘There are
several green-coated flints, and carbonaceous
layers sometimes occur.

¢
3 feet. eure i o% o.

3 feet
exposed.

[Vertical scale: 7 inch=1 foot.]

At a gravel-pit on the Bath Road, near the 300-foot contour
(No. 6 in the Map, Pl. XXX), I obtained another section :—

Feet.

STAVELLY BOIL... ..0stesreccees avs su ecm niches lae rw bn gS URe a ieees eee ene 2
Red loam, siliceous grains, and fine reddish clay (laminated more

BRECS) ier suena sales he maw CR AROOR AT EE eR OG EOE ae ee 2
Coarse fiint-gravel, slightly bedded, with occasional thin lenti- )

cular inclusions of stiff, dark clay-with-flints .................:000065 | 7
70 °/, large subangular brown-stained flints, with smaller ones in- {

termingled; 20 °/, large black flint-nodules coated white, slightly r od

rolled ; 5 °/, well-rounded, stained flint-pebbles, always small, | PS®®

A few slightly rounded green-coated flints ..............c..eseeeeeeee

—

The colouring and appearance of the strata exactly coincide in the
three sections last described.

The main points of difference between the Southern Drift and
this Donnington gravel are:—(1) The great disparity in levels,
amounting to a difference of about 120 feet. (2) The composition ;
the Glacial (Donnington) gravel containing numerous sarsenstones,
also green-coated pebbles, gritstones, and large black flint-nodules,
which are absent from the Snelsmore and Greenham Drift.
(3) The presence of Bison or Bos and Llephas at Donnington,

Vol. 53.] ASSOCIATED DEPOSITS AT NEWBURY. 425

peculiarly ‘Glacial’ species. (4) The non-occurrence of any
fossils in the Southern Drift. The colour of the latter is grey,
and the gravel is invariably bleached in the upper layers ; whereas
the Donnington gravel is always of a rich ferruginous brown. The
matrix of both is a clayey quartzose sand; though clean patches,
entirely free from clay, are often intercalated in both Drifts.

The Donnington gravel appears to thin out to the west, as the
watershed region upon which it lies rises above the level of the
gravel. Eastwards the carving out of the two valleys at their
junction has of course removed it.

The northern boundary of this gravel is the Lambourne Valley ; :
the southern is formed by the Kennet Valley, and the rising
ground limits it westward.

§ 4. Tue Upper RIvER-GRAVEL OR TERRACE-GRAVEL,

Below the level of the ‘Glacial Drift,’ at Newbury, there are
fine broad terraces of ‘ River-gravel’ on both sides of the valley.
These terraces I have called ‘ Upper River-gravel’ for the purposes
of this paper. Where the base has been exposed, it is seen to rest
upon firm green sands, which I conjecture are the lowest beds
of the Reading Series, from the evidence given by the well at Green-
ham Park (p. 422). The Upper River- gravel is usually about 12 feet
thick at the terrace-edges nearest the river. In Bull’s Lane, on
the south side of the valley, I obtained the following section :—

Fig. 3.—Section in the Upper River-gravel at Bull’s Lane.
(No. 7 in the Map, Pl. XXX.)

2 feet.

3 feet
exposed.

[Vertical scale: 4 inch = 1 foot.]

a. = Flint-gravel of the same Eiipisitian as c, but coarser. Surface unseeu.

b = Fine, soft, mealy quartzose sand with black, carbonaceous grains. Weathers
to a ferruginous yellow. This bed thins out at 20 yards, in the direction
of the arrow.

c = Coarse flint-gravel, with large unstained, black, and white-coated flints,
1 green-coated flint, and a few red flints. No gritstone: a few rounded
pebbles of quartzite and small flints. Composition as follows: 80 °/,
subangular brown fliats, 19 °/, rolled black flints, and 1 °/, subangular
sarsens, whose longest diameter is 12 inches. The matrix of the gravel
is brown clay.

426 MR. E. P. RICHARDS ON THE GRAVELS AND [ Aug. 1897,

Here a lenticular mass of soft green sand is the lowest bed
exposed, of very irregular thickness, and with an eroded surface,
upon which the terrace-gravel rests. I consider this sand to have
been derived higher up-stream from a former exposure of the
hard green sand first mentioned. The surface-level is usually about
260 feet above O.D., but rises and falls with the general level of
the river above and below Newbury, as is natural in a river-terrace
gravel.

A very typical section, about 26 feet deep, is exposed in the
Enborne Road gravel-pit, a little west of Newbury, and on the south
side of the Kennet. It is very near the edge of the terrace.

At the base of the section (fig. 4) a thickness of 12 feet is

Fig. 4.—Section in gravel-pit on the Enborne Road, near Newbury.
(No. 8 in the Map, Pl. XXX.)

[Vertical scale: 1 inch = 20 feet. Horizontal scale: 1 inch = 40 feet.

occupied by hard, green, slightly bedded, ferruginous sand, to
which the overlying mass of river-gravel is sometimes conform-
able and sometimes unconformable. Hard, much oxidized, ferru-
ginous nodules, about 2 inches in diameter, are fairly numerous:
they weather concentrically. The surface of this sand, upon which
the river-gravel rests, is eroded: swallow-holes and inclusions of
gravel being frequent in the upper portion. There are usually
small sarsens' and large flint-nodules, the latter both stained and
black, resting on the eroded surface, at intervals. This hard
green sand may be the base of the Reading Series, judging from
the evidence obtained in the Greenham Park boring (p. 422). The
occasionally apparent conformity of the river-gravel, I was inclined
to think (at the time of observation) due to concentric weathering
of the sand from the eroded surface downward : the river-gravel
being very permeable to water, and possibly to air. I may add that
this was a freshly-exposed section.

The gravel shown in fig. 4 is coarser than at Bull’s Lane, and
‘a few carbonaceous layers occur ; its composition is as follows :—

2 About 12 inches in their longest diameter.

Vol. 53. | ASSOCIATED DEPOSITS AT NEWBURY. 427

60 °/, subangular brown flints of all sizes.
‘ re) > black 2” 9
10 °/, well-rounded brown and black flints.

9 °/, subangular sarsens, up to 6 inches in longest diameter, coloured
variously brown and grey. These sarsens are bigger where they
rest on the sand.

1 °/, subangular green-coated flints.

The composition of this gravel does not tell us much, though a
comparison with the other gravels shows it to have been derived
from them both, with perhaps débris from the Reading Beds brought
from higher reaches of the Kennet Valley; the larger percentage
of rolled flints is noticeable. The level (260 feet above O.D.) of this
gravel, and its exceptionally fine broad terraces, however, leave no
doubt as to its order of formation. Geologists visiting Newbury
can obtain a most comprehensive view of these Upper River-gravel
terraces, from the Great Western Railway-bridge in Gashouse Road.

Worked flints of Paleolithic type may be picked up in the
ploughed fields that cover the Upper River-gravel. They are
usually rolled and stained like the flints. I have not been able to
secure any from the gravel itself.

The animal remains were found in groups; and as the bones are
quite unrolled and in fair preservation, we may consider the fauna
to have inhabited the near vicinity. I obtained all the fossils in
this Upper Gravel myself, with the exception of Hlephas primt-
genius, which was found during excavations for the Great Western:
Railway some years ago.

Mr. E. T. Newton, F.R.S., to whom I am greatly indebted,
kindly named these bones, in addition to other mammalian remains
from Newbury. The list from the Upper River-gravel comprises
Ovis, Bos taurus, Sus scrofa, Equus caballus, Rangifer tarandus,
and Bos primigenius.”

The Upper River-gravel is not well shown on the north side of
the Kennet (see Pl. XXX. section AB), owing to local disturbance
through road-making, though 4 mile farther up-stream the terrace
is clearly defined. A fault in the Chalk almost follows the northern
terrace-edge at Newbury, and its probable position is shown in
section AB. This fault was predicted by Prof. T. Rupert Jones, F.R.S.,
before our excavation confirmed it, his reason being the copious and
steady supply of Chalk water obtained by sinking some 20 feet at
the Newbury Waterworks in Northcroft, situated upon the line of
fault which runs east and west with the valley.”

§ 5. Tur Lower RivEeR-GRAVEL.

The Lower River-gravel, resting at Newbury upon the Chalk,
chiefly occupies the centre of the valley; it forms the base upon
which the Neolithic peat and shell-marl have been deposited, and

1 [A large tusk of mammoth was found by the late Dr. Silas Palmer, of
Newbury, in this gravel by the river-side at Northcroft Lane in that town, some
years ago.—T. R. J.]

* Note III. in Appendix I., p. 4383.

, 428 MR. E. P, RICHARDS ON THE GRAVELS AND [Aug. 1897,

is the lowest gravel found at Newbury. It appears to be a gravel
derived from all the other gravels mentioned, but with a larger
percentage of flints direct from the Chalk. The finest section was
exposed at the pumping-station of the drainage-works, in the flat
water-meadows near the Kennet (on Cook’s Farm), represented by
fig. 5. The base of the gravel is about 240 feet above O.D. The
white flinty clay underlying this was sticky, adhering tenaciously
to the flint-nodules intermingled with it. ;

Fig. 5.—Section at the Pumping-station of the Drainage-works.

Peaty soil and peat, with Neolithic flint-
implements.

MME

Stiff, pale yellow, sandy, homogeneous clay.

bo

Clean flint-shingle, grey in colour, sarsens up to
12 inches in diameter near the base, and small
chalk-fragments intermingled throughout.

Composition :

‘U 70 0/9 brown flints, most of them nearly rounded,

5| the rest subangular ;

=.|209/9 subangular, white-coated, black flints

=| (black where worn) ;

Uy; | 10 9/9 subangular, ferruginous gritstone, green-
“| coated flints, large subangular sarsens, and

flint-nodules.

103 feet.

White sandy clay, with black flint-nodules and

4 feet. chalk-fragments.

5 feet my) etm il

exposed. ‘| Chalk-with-flints.

lea |
Tr Wy a «wh
i [| M). pi
a en

[Vertical scale: $ inch = 1 foot.]

About 30 yards north of the pumping-station I obtained the
section shown in fig. 6, This gravel usually has a grey appearance :
the flints, unless rounded, being much battered and abraded. The
matrix is frequently absent; when present, it is of the cleanest
quartzose sand, and rarely the upper portion has a matrix of white
shell-marl, loosely filling the interstices. The water percolated
through this gravel into our sinkings at an extraordinary rate,
necessitating the use of three steam-pumps at one time, to keep the
water from rising in a shaft 19 feet square, when only sunk 15 feet

Vol. 53.] ASSOCIATED DEPOSITS AT NEWBURY. 429

deep. The currents which had dealt with this lowest gravel appear
to have been extremely violent, judging from the battered condition
of the flints, and the absence of any matrix but the coarsest clean
quartzose sand.

Wave-action and storm-beaches would be inferred if near the
coast, as the gravel rises in curious ridges, which traverse the
valley from side to side, more or less at right angles to the present
course of the Kennet. These mounds show very little, or not at

Fig. 6.—Section 30 yards north of the preceding.
(No. 10 in the Map, Pl. XXX.)

Peaty soil and peat, with Neolithic flint-
implements.

Stiff, pale-yellow, sandy, homogeneous clay.

io

Grey, clean flint-gravel, matrix of quartzose

6 feet. sand. The same as in fig. 5, p. 428.

5 inches. pare

3 feet
exposed.

all, upon the surface; but the peat, clay, and marl thin out over
these old lines of lake-barriers. This is what we expect, and have
found, in valleys debouching upon the sea-coast; and at Newbury
the lacustrine deposits certainly in several instances do repose
behind successive barriers of this battered gravel.

No traces of shells or organic remains of any kind have, however,
been forthcoming from this gravel, and we know of no submergence
at the period whereof we treat which turned the Kerinet Valley into
an arm of the sea; the wave-action hypothesis is, therefore, unten-
able. Is it possible that ice-action, or heavy water-action following
the close of the Ice Age, could have had anything to do with the origin
of the barriers? Here fuller investigation is doubtless necessary.

430 MR. E. P. RICHARDS ON THE GRAVELS AND [ Aug. 1897,

§ 6. Tur Neotiraic Laxe-Series anp Recent Deposits.

Section CD, in Pl. XXX, shows two of these ridges (see Map),
which I have been able to trace more or less completely across the
valley. Gaps appear in them near the present river-channel ; and
they appear to have been cut by ancient river-action, which gradually
drained the lakes, leaving the peat and marl to ultimately clothe
themselves with meadow and wood.

The typical strata in these Neolithic lake-basins are well illustrated
in fig. 7, taken in Northbrook Street. The beds shown in this
interesting section are fairly constant throughout the two lake-sites,
with the exception of the green loam, which is frequently absent.
The successive stages of formation, and the subsequent disappearance
of the lakes, are well marked by the strata. First the clay, pro-
bably deposited over the lower gravel by the river when in flood ;
next the partial barrier, producing a peat-marsh and the peaty
pools, in which the green loam was laid down; followed by a
further raising of the barrier, sufficient to drown the peat and form
a lake, the water teeming with the mollusca found in the white
shell-marl ; and lastly, the breached barrier draining the lake.

The peat and marl are very constant associates throughout; and,
as a rule, where the peat is thick the marl is thin, and vice versa.
This I account for by supposing the thin peat to indicate the deepest
parts of the lake-bottoms, which would be the first portions con-
verted into pools, stopping the growth of peat and giving a more
prolonged period for the deposition of marl. The contrary of this
would, of course, explain the thick marl and thin peat; the differ-
ences in level, however, are not sufficient to clearly show this.

Taking this little lake-series in order:—the base, which rests
upon the ‘ Lower River-gravel, is generally a bed of very stiff,
dark-yellowish clay, probably resulting from the denudation of
surrounding London Clay hills. Several roughly-worked black flints
were found in this clay, and occasional pieces of rolled wood, but
no bones.

The green loam lying above it consists of about equal parts of
fine sand and dark-greenish clay. Freshwater shells and logs of
birch and oak, with leaves, twigs, and nuts of the hazel, occur
frequently, and are identical with those in the peat above. I
obtained a pelvis of roedeer from the green loam near the pumping-
station. ;

The peat next in the series is of great interest as being here the
chief repository of human relics.!. Among those found were flint-
implements, one fragment of carved bone, pieces of sun-dried
pottery, and bone-drills, all of Neolithic types. No bronze or iron
weapons were found in the peat. I observed a kidney-shaped
pebble of Bath Oolite in the peat, the presence of which I attri-
buted to human agency.

As in the green loam underneath, logs of birch, oak, and fir
(trunks and roots) were abundant. I also found large tree-fungi,

1 Note IV. in Appendix I, p. 433.

Vol. 53.] ASSOCIATED DEPOSITS AT NEWBURY. 431

elytra of beetles, sedges, bracken, and hazel-nuts. Bones and teeth
of the following animals occurred :—

1. Bos longifrons. 7. Sus scrofa.

2. Rangifer tarandus (?). 8. Ovis.

3. Cervus elaphus. 9. Canis familiaris.
4. Capreolus caprea. 10. Canis lupus.

5. Equus cubatlus. 11. Mustela martes.

6. Capra hircus.

The reindeer was represented only by a drilled and ornamented
piece of antler, and it is doubtful whether this animal was contem-

Fig. 7.—Section in Northbrook Street, Newbury.

© 4 ’
Paes aa

G E tole
guess owe
L ° :
25 feet. |9 Se§sh 2 POURS: Modern macadam.
Cord ees ae ee

“| Medizval black road-metal, consisting of old
#| road-surfaces oneuponanother. The presence
of leather and horse-shoes throughout is con-
clusive of the age indicated. Black, owing to
old sewage-impregnation.

Freshwater shell-marl with Hquus caballus and

13 foot. Cervus elaphus.

Brown and black peat, with hazel, birch, oak,
fir, and bones of wolf, boar, Bos longifrons,
etc.- Also elytra of beetles, tree-fungi, fresh-
water shells, and Neolithic flint-implements.

35 feet

LZ Green loam of sand and dark clay, containing
LE many freshwater shells, and the same remains

2 feet LZ
LZ as the peat, excepting worked fiints.
I} Stiff dark greenish-yellow clay, with a few rudely-
1 foot. | ih worked flints.
Ee eal
oe <2 ge O035%* <P 070, F 2 ee
BAY fe g.8 e 4} The lowest river-gravel, as at the pumping

3 Oa aes oe On é. station (figs. 5 & 6, pp. 428 & 429).
[Vertical scale : z inch = 1 foot.]

porary with the peat. The other remains, both vegetable and animal,
indicate a temperate clime, unsuited to the reindeer. This piece of
antler, however, is interesting as being a slender bit of evidence for a
migration of Man from the North. The marten, however, indicates
a colder climate than that of modern Berkshire.

432 MR. EB. P. RICHARDS ON THE GRAVELS AND [Aug.1897.

I found numerous flint-implements in the peat, including one
axe-like instrument, many scrapers, knives, and needle-like flints,
together with wasters in abundance. Traces of fire were frequent
in calcined flints and quantities of charcoal-fragments. Nearly all
the marrow-bones of the animals were split longitudinally. Many
of the flints were quite unused, and their fine keen edges distinctly
indicated that they had been made where found.

The freshwater marl, composed of land and freshwater shells,
attains its greatest thickness, 8 feet, in Market Street. Here, as
elsewhere, it is very loose and friable.’ It is always white or
greyish in colour.

A list of shells has been very kindly supplied by Mr. B. B. Wood-
ward, F.G.8. (See Appendix II, p. 434.)

Mr. Woodward considers the series to indicate a climate similar.
to our own, adding, however,—‘ A more extended list might, of
course, furnish other data.’

I obtained also remains of the following animals :—Equus caballus,
Cervus elaphus, and Capreolus caprea. These always occurred in
groups, parts of single skeletons being dug out bone by bone, and
always quite unrolled. In the peat the bones were scattered.

Before leaving this part of the subject it should be mentioned
that we unearthed a pile-dwelling opposite, if not partly under, the
‘Coopers’ Arms’ in Bartholomew Street, a few hundred yards south
of Newbury Bridge, about 6 or 7 feet under the roadway. It was
constructed of fir-piles, about 6 inches in diameter, driven into the
peat, and with numerous parallel timbers crossing the pile-tops; the
surface of the platform was at the surface of the peat. We exposed
only a very small portion of this structure, and I was unable to find
the method of affixing the horizontal timbers to the piles. They
must have been fixed, otherwise when the lake covered them they
would have floated, for the marl covers the platform.

Just above the shell-marl and peat in Northbrook Street and
elsewhere is a black abraded gravel (see fig. 7, p. 481), consisting of
old layers of road-metal. The lowest are probably of Roman age;
the upper portions are medieval; the maximum thickness is about
7 feet. The whole has been blackened by ancient sewage. On the
top of this is the modern ‘macadam’; 18 inches beneath the pre-
sent road-surface cannon-balls and weapons of the 17th century
were discovered.

Prof. T. Rupert Jones, F.R.S., has very kindly given me his
valuable advice and useful help in finding references and in making
notes upon some important particulars. See Appendix I.

1 (Hard, ovoidal, concretionary nodules of the mar] have been noticed in this
deposit at and near Newbury, and close to the Thames at Old Windsor, Berks.
—T. R. J.]

Vol: 53. ASSOCIATED DEPOSITS AT NEWBURY. 433

Apprnpix I,

1. (1) Dr. Buckland treated of some points in the geology of
Newbury in his memoir ‘On the Formation of the Valley of
Kingsclere and other Valleys by the Elevation of Strata that
enclose them ; and on the Evidences of the Original Continuity
of the Basins of London and Hampshire,’ in Trans. Geol.
Soc. ser. 2, vol. ii. (1826) pp. 119-130, illustrated with a
geological map of ‘The Valleys of Kingsclere and Ham in the
Basin of Newbury’ (pl. xvii).

(2) The geology of the Newbury district was described and illus-
trated in ‘ A Lecture on the Geological History of the Vicinity
of Newbury, Berks,’ by T. Rupert Jones (1854). See also the
Rev. John Adams, ‘ Geological Sketch of the Kennet Valley,’
Wilts Archeol. & Nat. Hist. Soc. Mag. vol. xi. (1869) pp. 274,
ete.

(3) Prof. (afterwards Sir Joseph) Prestwich has alluded to several
particulars in the geology of the neighbourhood of Newbury
in Quart. Journ. Geol. Soc. vol. x. (1854) pp. 86, 87, & 129,
& vol. xlvi. (1890) p. 162.

(4) Geological notes on this part of Berkshire have been given in
Mem. Geol. Surv. Expl. Sheet 13, 1861; Expl. Sheet 12,
1862; and Expl. Sheet 7, 1864.

(5) Many facts and opinions as to the geological structure of the
district are mentioned in the four volumes of the Transactions
of the Newbury District Field Club, as follows :—vol. i. (1871)
pp. 21-32, 104-109; vol. 11. (1878) pp. 2-6, 64, 246-250 ;
vol. 11. p. 101 ; vol. iv. pp. 206-210.

II. A full account of the characters, position, and origin of the
sarsens or sarsenstones was given by Prof. T. Rupert Jones
in Wilts Archeol. & Nat. Hist. Soc. Mag. vol. xxii. (No. 68,
December 1886) pp. 122-154; with a bibliographic list of
references. In a note on p. 133 it is stated that ‘sarsens are
‘particularly abundant in the gravel of the Kennet Valley, near
Newbury’ (Enborne Road, for instance). These are small
waterworn pieces of the original large blocks, such as are
still abundant on some of the uplands traversed by the Kennet.

III. See Mr. Grover’s ‘ Report on the New Water-Supply at New-
bury, Trans. Newbury District Field Club, vol. ii. (1878)
pp. 246-248,

ITV. A human skull from the peat was referred to by Dr. Buckland
in Trans. Geol. Soc. ser. 2, vol. ii. (1826) p.128. Dr. Rolleston
described this skull and another in Trans. Newbury District
Field Club, vol. ii. (1878) pp. 241-245. Remains of two
other human skulls from the peat are mentioned by Dr. Palmer
in his memoir ‘On the Antiquities found in the Peat of
Newbury,’ Trans. Newbury District Field Club, vol. ii. (1878)
pp. 123-184. The Appendix to that paper (pp. 135-147) con-
tains interesting descriptions of the peat from older writers.

Q.J.G.8. No, 211. 24

434 MR. E. P, RICHARDS ON THE GRAVELS AND [ Aug. 1807,

Flints exhibiting traces of human workmanship, from the
peat-fields, have been noticed; and those found by the present
Author in the peat and gravels of Newbury are enumerated
at p. 208 (vol. iv.) of the same Transactions, in his notes
contributed to Mr. Walter Money’s memoir ‘ On the Prehistoric
and Medieval Antiquities found at Newbury during the
Drainage Operations in 1894.’ A general geological section
through Newbury (pl. ii) was also contributed by Mr. Richards
at the same time.

A list of mammalian remains from the peat and marl was
published in T. Rupert Jones’s ‘ Lecture Geol. Newbury,’ 1854,
p.-41. This was copied in Mem. Geol. Surv. Expl. Sheet 12,
1862, p. 48, with a mark of doubt to Ursus speleus [?]. It
may probably have been JU. arctos.

In Dr. Palmer’s memoir above referred to (pp. 131-133) the
list of mammalian relics from the peat-beds includes—

Wolf. Ass.

Badger. Red Deer.

Otter. Roe.

Bear. Goat.

Beaver. Gigantic fossil Ox, or Ure Ox.
Water-Vole. Long-fronted or small fossil Ox.
Horse. Wild Boar.

See also Owen’s ‘ British Fossil Mammals and Birds,’ 1846,
pp- 198 ete.

Such as were found during the excavations for the drainage
in 1894 are briefly mentioned in Trans. Newbury District Field
Club, vol. iv. (1895) p. 209.

An antler of Cervus megaceros is said to have been dug out
of the peat of the Kennet Valley a few miles below Newbury,
Geol. Mag. 1891, pp. 95 & 480.

VY. Prof. T. Rupert Jones’s list of the land and freshwater shells
found in the peat and shell-marl was reproduced in Mem. Geol.
Surv. Expl. Sheet 12, 1862, p. 48 (with the nomenclature
after Sowerby’s ‘ Illustrated Index,’ etc., 1859, instead of
Turton’s ‘ Manual,’ etc., 1840), and slightly shortened.

The seed-vessels of Chara were also noticed, and some
Cypridide, which were described (Annals & Mag. Nat. Hist.
ser. 2, vol. vi. 1850, pp. 25-27 & pl. ii. figs. 3, 7 & 8) as Cypris
setigera, Candona reptans, and Candona lucens.

Apprenpix IT.

VI. Nores on the Mottvscea from the Kennet Vattey Depostts.
By A. S. Kewnanp, Esq., and B. B. Woopwarp, Ksq., F.L.S., F.G.S.

The first list of the mollusca from the Holocene deposits of the
Kennet Valley at Newbury was given in 1854 by Prof. T. Rupert
Jones (‘ Lecture on the Geological History of the Vicinity of New-
bury,’ pp. 41, 42), and contained fifty-onenames. The collection on
which this list was founded was made in 1842 by Prof. Rupert

Vols 53: | ASSOCIATED DEPOSITS AT NEWBURY. 435

Jones, and his friend Mr. J. Pickering furnished him with the list.
Two years later Mr. 8. V. Wood enumerated forty-five species, all of
which are contained in the previous catalogue, the printer perhaps
being responsible for the missing species (‘Monogr. Crag Mollusca,’
vol. ii. pp. 8304-310). In 1883 one of us pointed out that the
single example of Helix aspersa recorded as occurring in the New-
bury marl was probably of quite recent date, since the numerous
pits which from time to time have been dug in the peat quickly fill
up (‘Science Gossip,’ 1883, pp. 115, 237). This will also account
for the fact that Saxon remains have been found at a depth of
10 feet in the peat. All efforts to trace Mr. Pickering’s collection
have failed; but there is a series of shells from these and other
Pleistocene deposits in the British Museum (Natural History), which
series had been presented by him to the Geologists’ Association,*
and transferred by that body to the National Collection. This has
been supplemented from a series in our own possession.

From these sources we have been enabled to compile a list of
forty-two species, seven of which have not previously been recorded.
Besides Helix aspersa, it has been considered advisable to reject five
other records as being probable errors in identification, namely, imax
carinatus | = Amalia Sowerby, Fér.]; Zonites [= Vitrea] allaria ;
Helix hortensis, an error for H. nemoralis; Heliw [| =Helicella] vir-
gata, and Vertigo alpestris. Two of Mr. Pickering’s species are
now considered as only varieties of other forms.

The list thus shows now a total of fifty species :—

Agriolimar agrestis, Linn. Limnea pereger, Mill.

Vitrea nitidula, Drap. palustris, Mull.
radiatula, Ald. truncatula, Mill.

2 erystallina, Mill. z stagnalis, Linn.
Sulva, Mill. Planorbis corneus, Linn.

g nitida, Mull. albus, Linn.

3 Arion ater, Linn. 3 —_. glaber, Jeff.

nautileus, Linn.
marginatus, Drap.
vortex, Linn.

Pyramidula rotundata, Mill.
Vallonia pulchella, Mill. —
Hygromia hispida, Linn. —

= granulata, Ald. — spirorbis, Linn.

Zt rufescens, Penn. contortus, Linn.
Helicigona arbustorum, Linn. Z Jfontanus, Light.

3 Helicella ericetorum, Mill. 2 Physa fontinalis, Linn.”
Helix nemoralis, Linn. hypnorum, Linn.
Cochlicopa lubrica, Mill. Bythinia tentaculata, Linn.
Pupa muscorum, Linn. Leachii, Shepp.

3 Vertigo antivertigo, Drap. Valvata piscinalis, Mill.
pygmea, Drap. cristata, Mill.
Succinea putris, Linn. ? Neritina fluviatilis, Linn.

elegans, Riss. Spherium corneum, Linn.
Carychium minimum, Mill. Pisidium amnicum, Mill.

Ancylus fluviatilis, Mill. pusillum, Gmel.
— lacustris, Linn. Sontinale, Drap.
2 Tamnea auricularia, Linn. : milium, Held.

One egg of a small Helix was also found.

1 Proc. Geol. Assoc. vol. i. (1860) pp. 85-87.
? Included in the list on the authority of Mr. Pickering.
3 Not recorded before from Newbury.

262

436 MR. E. P. RICHARDS ON THE GRAVELS AND [ Aug. 1897,..

Of these the most noteworthy are Arion ater, Planorbis glaber,.
and Pisidium milium. The last-named form has hitherto been
unrecorded in a fossil state in this country. At the present time it
is a widely distributed, though local, species. Planorbis glaber,
though extremely abundant in Pleistocene deposits, is equally rare:
in those of later date, and its area of distribution has certainly
diminished. -Arzon ater has only once been recorded from any
deposit in this country, and that is one of doubtful age near Maid--
stone; but it has probably been overlooked, since the internal
calcareous granules are very small indeed, and these are the only
portions which would be preserved in a deposit.

Our collection has been derived from three sources :—firstly, a
series collected by one of us during an excursion of the Geologists’
Association to Newbury’; secondly, some specimens seut by Mr. F.
J. Bennett, F.G.S.; and, lastly, a large quantity of material for-
warded by Mr. E. Percy Richards, F.G.S. It is noteworthy that
from each a different series of forms has been obtained. Thus, in
the first case, Heliw nemoralis, Bythinia tentaculata, and Helicella
ervectorum occurred, though unknown in the other two. Mr. Bennett's -
specimens included numerous examples of Valvata piscinalis, which
are the only specimens that we have seen ; while the material from
the last source was certainly deposited in swampy ground and not
in deep water, as evinced by the abundance of Vertigo antivertigo,
Carychium minimum, Arion ater, Agriolimax agrestis, and Limnea
truncatula—forms which are characteristic of such localities.

PLATE XXX.

Map of Newbury and sections in the immediate neighbourhood of the town.

Discussion.

Mr. E. T. Newton referred to the careful and detailed work
contained in this paper, which he thought would prove a valuable
addition to our knowledge of the beds immediately succeeding the
Pleistocene gravels, and would help to a better understanding of
the events which came between Paleolithic and Neolithic times; .
he also remarked on the vertebrate-remains which had been collected
by the Author, not only from the undoubted Pleistocene gravels,
but also from the Neolithic and more recent deposits.

Mr. Moncxton thought it a pity that the term ‘ Glacial Gravel’
was used for the gravel near Donnington Square, as it did not
appear from the account of its composition given in the paper that
it belonged to the class of gravels included in the Glacial Drift by
most modern authors (see remarks by Mr. Whitaker, ‘ Geol. of
London,’ vol. i. 1889, p. 299). The speaker had examined all the
sections in gravel that he could find near Newbury, but had not
seen anything which he should include in the Glacial Drift. Thus -
he had not found boulders or pebbles from the Triassic pebble-beds -

1 Proc. Geol, Assoc. vol. vi. (1879) p. 185.

Quart.dourn.Geol. Soc. Vol. LI. Pl. XXX.

In DE Xx

sa PALAEOLITHIC pre,
‘ Se TERRACE BRAVEL 12 Ig SOUTHERN DRIFT
GRAVEL. TERTIARY

WHITE CLAY
WITH ELINTS BAGSHOT BEDS

GLACIAL (?) LONDON CLAY
== bg ea READING BEDS

regs] GLACIAL FLINT

fh] COARSER GRAVEL K
wan CHAK [sees] CHAL

ON LINES ----—-- —----------
)},6T7C. REFER TO SECTIONS IN TEXT
® TERRACES |-l—A +1-(—[-l-F-1-(-|-i-1

OF LOWER RIVER GRAVEL HAA api

SSS SSSss

50 3000 9140 FEET,

Mintern Bros. lith.

Quart. Journ Geol Soc Vol. Lill Pl Xxx.

MAP oF N

SECTION E.F.—— SWEWUOIMN C. 0),

INDEX

BARTHOLOMEW ST

NORTH BROOK ST

RSS

PUMPING STATION

PALAEOLITHIC tx

TERRACE GRAVEL feees| SOUTHERN DRIFT

Graver ee TERTIARY

rH RES BAGSHOT BEDS
LONDON CLAY
READING BEDS

SNH WORKHOUSE

WS

= > = s J 7 NEOLITHIC
x F3 = seesep moo , Ege | FRESHWATER
aad SAIN AS Sau ALIA PAT z . k SHELL MARL
ee Eopurs

GLACIAL (?)

'D SAND-AND-~
seray Laam
COARSER GRAVEL
veitn cumen [Seat] CHALK

i
4 CLAY
D EN LOAM
WITH SHELLS
ASTFIELDS |, SECTION LINES ~--—- -~~-~-~~_-~_

MAP ) 46. /0,arc_ REFER TO SECTIONS IN TEXT

RIVER TERRACES |--4 Hintm[- eli
RIDGE OF LOWER RIVER GRAVEL lisse

Verticar ScALteE 40 reer To % Incu.
HorizontaAt Scare 300 FEET To % I/ncu.

Ses
SCALE —1[f% INCHES TO

R KENNETT

----DONNINGTON SQUARE ---

SECTION A.B.

W. RAILWAY

BARTHOLOMEW St®

ae SAS

Riming eermuzisn
Se tee ts Lite tx Ft ee
tebe x et
toe XR XR eee
Bian (has Fs sp at Pe FR
: Kat ASS

EP Richards del.

Minton Bros. lith

res se nid Se ae

Vol. 53.] ASSOCIATED DEPOSITS AT NEWBURY. 437

or of igneous rock. Referring to the Southern Drift of Snelsmore
Common, the speaker said that a few quartz-pebbles up to 7 oz.
weight occur, but that he had failed to find fragments from the
Lower Greensand.

Mr. H. B. Woopwarp remarked that he had seen, under the
guidance of Mr. F. J. Bennett, some of the plateau-gravels near
Newbury, and he asked whether they might be of Bagshot age.
The only reason for grouping them as Drift seemed to be the fact
that these gravels contained a few foreign stones; but now that
Mr. Clement Reid had shown that the Bagshot Beds of Dorset con-
tained many kinds of rock-fragments, it would be well to reconsider
the age assigned to the high-level Newbury gravels.

Mr. A. E. Satter was much interested in the descriptions of the
various gravel-deposits, occurring as they do near the centre of the
valley of a river—the Kennet—the water-parting of which on three
sides was over 500 O.D. The composition of the gravels on
Snelsmore and Greenham Commons was singularly like that at
Upper Hale near Aldershot (615 to 475 feet above O.D.), where also
large sarsens occur near the base. Deposits referable to the
so-called ‘ Westleton Shingle’ were apparently absent, and no
mention had been made of the occurrence of Greensand chert.
According to the list of constituents given as occurring in the
Donnington and Bath Road gravels, they were not necessarily
of Glacial origin. They do not appear to contain any transported
material from the North, and as their situation is peculiar it would
be interesting to know upon what grounds they are so designated
by the Author.

Mr. R. S. Herries said, with regard to Mr. H. B. Woodward’s
suggestion, that he did not think the gravels on Snelsmore Common
could be of Bagshot age, and referred to a paper by Mr. Monckton
and himself in the Proceedings of the Geologists’ Association for
1889, where his reasons would be found.

Mr. W. Warraker also spoke.

Prof. T. Rupert Jonss replied on behalf of the Author.

438 DR. H. HICKS ON THE MORTE SLATES, AND [ Aug. 1897,

31. On the Morte States, and AssocrarEeD Bens, in NortH Devon and
West Somerset.—Part [1.1 By Henry Hicks, M.D., F.R.S.,
P.G.8S. With Dzscriprions of the Fosstzs by the Rev. G. F.
Wuippornet, M.A., F.G.S. (Read April 7th, 1897.)

[Puates XXXI-XXXV.]

ConrTENTS.
Page
Wey Etrodethianey. 3) 2S ac ecc ancmae decides aces wecaceadinete eee 438
Th The “Ereporour hy istricts. ....000.<<..cancespenncacsk eeneeeee 440
DIE "The Brendon Halls 445 222 Ae eee 442
TV. ‘Lhe Wiveliscombe District 0.0 5.00.002 A eee 449
V--General ‘Comeliasions (aii 6.655) secede osha ode oes ROR 443
Wil... Descriptions ofphe Posse...) 04k. na-notntnsaeack ease 445

I. IytrRopuctrion.

Since the first part of this paper was published (May, 1896) I have
had another opportunity of visiting North Devon and West Somer-
set, the former district as one of the Directors of the Excursion of
the Geologists’ Association in July 1896, and the latter district
in company with the Rev. G. F. Whidborne, M.A., F.G.S8., the
Rev. H. H. Winwood, M.A., F.G.S., Mr. J. G. Hamling, F.G.S.,
Mr. R.S. Herries, M.A., F.G.8., and Mr. Upfield Green, F.G.S.
The only addition to the fauna in North Devon was the dis-
covery near Barricane, in Morte Bay, of a portion of an Orthoceras
(by Dr. Barrois, F.M.G.8.) ; but in West Somerset some forms not
previously known to occur in that area were obtained.

The faunas so far discovered in West Somerset differ very
markedly from those found in the Morte Slates in North Devon, and
belong to higher horizons in the succession ; but it must be under-
stood that there are still large areas which have been but imperfectly
explored. Inso great a thickness also, occupying an average width
in West Somerset of from 5 to 6 miles, it is only natural to
suppose that several other faunas must occur, especially as in
the faunas already described there appear to be few, if any,
fossils incommon. As many parts of this district are very in-.
accessible, and the exposures comparatively few, much time will
have to be spent before anything like a complete examination can be
made. The evidence so far obtained, however, is so important in its
bearing on the succession of the Devonian rocks in North Devon
and West Somerset that [ venture to submit it to the Society.

The first discovery of fossils in the so-called Morte Slates.
of West Somerset was made in the spring of the year 1895 by
Mr. Whidborne, Mrs. Whidborne, and myself in the slate-quarry

? For Part I., see this Journal, vol. li. (1896) pp. 254-272 figs. & pls. x—xi.

Vol. 53.] ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET. 439

at Treborough. (See Map, Pl. XXXV, & section, fig. 1.) In
July of the same year Mr. Hamling was good enough, at my
request, to visit the Oakhampton slate-quarry near Wiveliscombe,
and afterwards to send me some specimens. In the following August
Mr. Hamling, Mr. Whidborne, and I collected other specimens from
this quarry, and afterwards we also obtained some fossils from the
Combe quarries near Whitfield, on the opposite side of the ravine

Fig. 1.—Section from Treborough to Withycombe.

Treborough
Ss & Rod Huish
eet ; Withycombe N

waren e te eoe

4

UY
7 \
RSS
‘

SANS sos Sa
/fracombe Series
Middle Devonian)

YY; YM YY
te Slate Series
(Lower Devonian)

—~=>

[Horizontal scale = about 1 inch to the mile. }

(fig. 2). Both the Oakhampton and the Treborough quarries have
been since visited by us on many occasions, and numerous fossils
have been collected from each. We have also made several traverses
across the district intervening between Treborough and Oakhampton,
and have explored the rocks to the north and south, and collected
largely from those beds.

Fig. 2.—Section from North Down to Battin’s Farm.

S ‘Langley Battins Farm N
North Down Marsh H
'

PSR =
= YG

Pick well Do

é

wn Beds, ée.

Yr -asition of Oakhampton House Slate-quarry on line of strike,
[Horizontal scale = about 1 inch to the mile. ]

(Lower Devonian )

F.. Fault

The so-called Morte Slates vary considerably in character in dif-
ferent areas, and probably include beds of very different age. Some
of these may be faulted patches thrust in among the older rocks ;
but as there is no paleontological evidence to guide us as to their
age, they cannot, at present, be properly classified. Faults are of
frequent occurrence, and the beds in places are much crushed, though
not so much as in North Devon. The boundary-lines between the

440 DR. H. HICKS ON THE MORTE SLATES, AND [Aug. 1897,

so-called Morte Slates and the Ilfracombe Beds on the north, and
between the former and the Pickwell Down Beds on the south, are
probably throughout faulted junctions. Many areas beyond the
limits of the accompanying map have been examined, but the only
new evidence of importance from those areas has been the discovery
of plant- and fish-remains in the Pickwell Down Sandstones, which
are in contact with the Morte Slates near Barlinch Abbey in the
Exe Valley, and of plant-remains in the Hangman Grits at Timbers-
combe. I must not omit to express my great indebtedness, for
much valuable information and guidance to localities, to the
valuable papers on these areas by Mr. R. Etheridge, F.R.S., and
by Mr. Ussher, F.G.8., of the Geological Survey, and the late
Mr. Champernowne, F.G.S.

II. Tur Treporover District.

The line of junction between the so-called Morte Slates and the
Iifracombe Beds in this area has been hitherto but imperfectly
defined, mainly owing to the fact that there is at Treborough a
fairly thick band of limestone in association with the slates ; for, as
is well known, it has been generally assumed that the Morte Slates
in North Devon are entirely devoid of limestone-deposits.’ In his
map (Quart. Journ. Geol. Soc. vol. xxiii. 1867, p. 580) Mr. Etheridge
gives the line of division as north of Exton, passing by Treborough
to Monksilver, and at p. 602 he says :—‘ It may be assumed with
but little hesitation that a line drawn from Lee Bay to Challa-
combe (north of Bratton Down), Eyeson Hill, and Treborough
would nearly indicate the marked division that takes place between
the lower group of slates, with its associated limestones and well-
marked Middle Devonian fauna, and the higher, pale-grey, glossy,
unfossiliferous series, accompanied by the quartz-veins that form so
conspicuous a feature at Lee Bay, Bull Point, Rockham Bay, and
Mortehoe,* and which unmistakably strike from the sea on the west
to Wiveliscombe on the east, passing north of Bittadon, Arlington,
Withypool, Winsford, the Exe Valley, and Exton Hill,’ a distance
in length of over 40 miles. Mr. Ussher, in his map in the Proceedings
of the Somersetshire Archeological & Natural History Society for
1889 (vol. xxxv) has not attempted to separate the Morte Slates
from the Ilfracombe Beds, merely dividing them as Upper (Morte)
and Lower (Ilfracombe) Beds in the Middle Devonian, and at p. 20
he says :—‘ These slates occupy an area of about 90 square miles in
Sheet 20. There is even less distinction between the upper and
lower portions than in the typical districts from which their names
are derived. The upper part is less evenly fissile than in North
Devon, and does not maintain so uniformly its pale green-grey tint.

1 Tt is amistake to say that there are no limestone-bands in the Morte Slates
of North Devon, for I have found several, usually in a decomposed state on the
surface, in Morte Bay, Lee Valley, and elsewhere.

2 In the first part of the paper I stated that the quartz-veins so frequently
seen in the Morte Slates in North Devon occur in fault-lines, and where the
folds have been much crushed.

Vol. 53.] ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET. 441

The lower beds are distinguished, as a whole, by the presence of
grits and masses of limestone, and by greater variety of colour and
texture.’ |

As the Treborough Slates are unlike any slates which occur in
the typical Ilfracombe Beds, and are essentially like the slates which
crop up in the adjoining areas to the south, marked by all as ‘ Morte
Slates,’ it is quite clear that they should be classed with the latter,
and not with the Ilfracombe Beds. Moreover, the Ilfracombe Beds,
as may be seen in the section (fig. 1, p. 439), are separated from
the Treborough Slates by a well-marked fault. The paleontological
evidence also shows that these slates belong to much lower horizons
in the succession than the Ilfracombe Beds. The stratigraphical
evidence further seems to point to a physical change of some
importance as having affected the area after the deposition of the
Treborough and Oakhampton Slates, and before the Ilfracombe
Beds had been laid down. The lowest Ilfracombe Beds, imme-
diately beyond the fault, are massive sandstones, sometimes con-
glomeratic, dipping away to the north-east at a low angle (about
20°). The Treborough Slates south of the fault, on the other hand,
dip at a high angle (60° to 80°) almost due south. No fossils had
been recorded from the Treborough slate-quarries until we discovered
them in 1895, though numerous forms characteristic of Middle
Devonian rocks in other areas have been mentioned by Mr. Etheridge,
Mr. Spencer Percival, and others, from the limestone-bands in the
Ilfracombe Beds to the north, namely, at Goldsoncot, Rod Huish, and
Withycombe.’ These beds, as shown in the section, are repeated
in gentle folds with a general inclination to the north-east, hence
away from the Treborough Slates. In the Treborough quarries the
fossils described by Mr. Whidborne occur in beds below the lime-
stone-bands, and the latter at present have yielded only fragments
of encrinites and some imperfect corals. These limestone-bands are
much cleaved, and differ greatly in appearance from any of the
limestones in the I/fracombe Beds to the north. They also contain
much more argillaceous material than the latter. The slates in the
quarry are hard and well cleaved, and, as the cleavage runs nearly
in the line of the bedding, the fossils on the whole are not much
distorted. The most characteristic fossil seems to be the large
Strophomena (originally Leptena explanata, and mentioned by
Sowerby as occurring in the then so-called Silurian rocks of the
Rhenish provinces), of which a great number of specimens have
been collected. Up to the present the following is the list, as made
out by Mr. Whidborne :—Dalmanites sp., Homalonotus sp., Gosse-
letia?? Kayseri, Frech, sp.?, Cypricardinia? sp., Grammysia? sp.,
Spirifera sp., Strophomena (Stropheodonta) explanata (Sowerby),
Streptorhynchus ? persarmentosus (M‘Coy), Chonetes plebcia, Schnur,
Ch. sarcinulata, Schlotheim, Petraia sp., Eridophyllum sp., Clado-
chonus sp., crinoid-segments, and sponge-spicules.

1 At Rod Huish we collected numerous corals and other fossils in a fine

state of preservation, which Mr. Whidborne at once recognized as the same
species as those found in the Middle Devonian Limestone of Torquay.

442 DR. H. HICKS ON THE MORTE SLATES, AND [Aug. 1897,

IIl. Tue Brenpon Hitts.

In following the section southward from Treborough Quarry,
there appears to be very little change in the character of the
deposits until we reach Treborough Common, and the dip is every-
where at a high angle. Here, however, the beds are more sandy
and flag-like in character, but often much crushed. The change is.
so marked that I have classed them under the name of Brendon
Hill Series. At some points they could easily, from their mineral
character, be classed with some of the Hangman or Pickwell Down.
Beds ; and beds of like appearance farther west have been coloured
by Mr. Ussher on his map as Pickwell Down Beds, thrust in by
faults among, or reposing upon, the Morte Slates. They occupy
an area of more than a mile in width, and the Brendon Hill mines.
of iron-ore occur in them. The evidence would lead one to suspect
that some at least of these beds are much newer than the Tre-
borough or Oakhampton Slates, and that they occur here as the
result of faults, in a crushed and broken condition, among the
older rocks. They extend evidently fora considerable distance in an.
east-and-west direction, and form the highest ground in the area.
South of the Brendon Hills slates are again found on the surface,,.
the beds dip at a high angle, and are repeated in numerous folds
until we reach the neighbourhood of the Oakhampton and Combe
slate-quarries.

IV. Tue Wive.iscomsBE Districr.

The slates of the Oakhampton and Combe quarries north of
Wiveliscombe have been universally classed with the Morte Slates
of North Devon, and Mr. Etheridge refers to them in the following
words (Quart. Journ. Geol. Soc. vol. xxiii. 1867, p. 592) :—‘ From
Hawkham through the Oakhampton House Quarries, Whitfield, etc...
we are unmistakably in the grey fissile slates of Mortehoe and
Morte Bay, which here dip south from 65° to 70°, with cleavage
coincident, but in some places nearly vertical; the same system
of quartz-veins that occurs at Lee, Mortehoe, and Woolacombe
occurs here—a circumstance, connected with other features, tending”
to clearly identify their position below the range of the Upper Old
Red Sandstone before mentioned.’ Mr. Etheridge makes the slates.
pass conformably under the Pickwell Down Sandstones of Maun-
down; but Sir H. De la Beche and Prof. Jukes inserted a fault
between the two series, and indicated it as passing in an east-and-
west direction through Langley Marsh. It seems to me that there
is undoubtedly a well-marked fault here, and the beds are much
crushed in the valley which intervenes between the sandstones on
the south and the slates on the north side. Prof. Jukes, however,
instead of placing the slates on a lower horizon than the sandstones,
supposed that the latter, which he called Old Red Sandstones,
passed under the slates, which he classed as Carboniferous Slates.
In this he was entirely mistaken, as the slates are now known to
contain Lower Devonian fossils. No fossils had been found in the:

Vol. 53.] ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET. 443:

slates of Oakhampton and Combe until we searched them in the
summer of 1895, but in that year and afterwards we discovered
several important fossils in the slates, and these have now enabled.
us to fix the horizon of the beds with tolerable accuracy. One of
the most important fossils discovered is Crypheus laceniatus, a
characteristic Lower Devonian fossil both in Europe and America.
The fossils defined by Mr. Whidborne are :—Crypheus laciniatus,
F. Romer, Limoptera semiradiata, Frech?, Aviculopecten mundus,
sp. nov., Spirifera sp., Rhynchonella hercynica, Kayser ?, th. nympha,
Barrande ?, Stropheodonta teniolata, Sandberg., sp., and crinoid
remains.

In the section (fig. 2, p. 439) it will be seen that the beds at
Whitfield, near the Combe quarries, are at a very high angle, and dip
to the south. A like dip can be traced in the ravine which separates
these quarries from the Oakhampton quarries for 14 mile to the
north ; but there are indications of several folds in the beds. Between
that point and the Brendon Hill Beds the exposures are less clear,
though there is no marked change in the character of the sediments.
The few fossils obtained from the Combe quarries agree with those
found at Oakhampton Quarry, and up to the present no other well-
marked zone of fossils has been found in this area. The beds
in places certainly resemble some of the Morte Slates of North
Devon, but they are, on the whole, of a darker colour and less hard..
They are also much less crushed, and the cleavage is nearly in the
line of the bedding. Slaty beds can be traced continuously in a
westerly direction from here to near Dulverton in the Exe Valley,
but up to the present they have not yielded any fossils in that area.
The evidence seems to point to an extension of the fault from
Langley Marsh to the Exe Valley, marking the boundary between
the Pickwell Down Beds and the so-called Morte Slates. The
Pickwell Down Beds, however, frequently dip at a low angle, and.
are repeated in several folds to the south. Resting upon them are
beds resembling in a marked manner the Sloly Beds near Barnstaple,
and upon the latter occur Pilton Beds full of the usually charac-
teristic fossils. The Pilton Beds also are repeated in several folds, and
they can be examined in various quarries in the Tone Valley west
of Wiveliscombe. These beds have been well described in the paper
by Messrs. Champernowne & Ussher in this Journal, vol. xxxv.
(1879) p.542. Farther south the Pilton Beds are succeeded by the:
Culm Measures, with chert-bands, as in North Devon.

r

V. Generat Conciusions.

It has now been shown that the so-called Morte Slates of North
Devon and West Somerset, which, up to the time when we com-
menced our researches among them, were always considered to be
barren of organic remains, contain several zones of fossils, and that
beds of very different horizons have been included under that term.
In North Devon evidence has been brought forward to show that
some of the beds are of Silurian age, as the fossils are unlike any:

AAA THE MORTE SLATES AND ASSOCIATED BEDs. [ Aug. 1897,

‘known to occur in the Devonian, but agree well with fossils which
occur in the Silurian rocks in other areas, especially in Pembroke-
shire, on the opposite side of the Bristol Channel. Up to the
present, four well-marked zones have been made out, two in North
Devon and two in West Somerset. Few fossils appear to range
from one zone to the other, and none between the zones in North
Devon and those in West Somerset, which latter appear to be on
higher horizons than any as yet discovered in North Devon. In so
great a thickness of beds, however, there is a possibility that other
zones may yet be found, as the nature of the sediments would lead
one to suppose that there is a gradual passage from the lower
(Silurian) to the higher (Lower Devonian) slates, and that if there
is a physical break in the succession it must be above these slates.
‘The presence of typical Lower Devonian fossils in the slates of
West Somerset is a fact of great importance, for it shows that there,
as in North Devon, the oldest beds occur in the centre of the area,
and that there cannot be a regular upward succession, as has been
supposed, from north to south. Indeed, there are numerous ex-
posures which indicate that the beds are thrown off to the north
and to the south from this central axis. The questions relating to the
comparative age of the beds north of this axis and that of those on
the south have not, at present, been completely worked out; but
that they are in each case newer than the typical beds of the central
axis is abundantly clear. In the Ilfracombe Beds on the north and
the Pilton Beds on the south there appear to be several fossils in
common, but none between either of these and those of the so-called
Morte Slates which form the axis. So important a difference in
the faunas could not have occurred unless the beds were on markedly
different horizons. The beds, therefore, classed as Morte Slates
in North Devon and in West Somerset cannot, in future, be placed
as passage-beds between Middle and Upper Devonian, but must be
looked upon as older than, and in each area as underlying, the
Middle Devonian Beds.

If the fossils found at Treborough and at Oakhampton be com-
pared with’ those found in the well-known Lower Devonian in the —
Rhenish area, we find that the Treborough fossils (Chonetes sarea-
nulata, Ch. plebera, etc.) occur there in the lowest beds; and that
Crypheus laciniatus, which is a characteristic Oakhampton Quarry
fossil, occurs in the Rhenish area in higher beds of the Lower
Devonian.’

[1 Since the reading of this paper our attention has been directed to the
following passage in M. D. P. Cthlert’s paper on the ‘Devonian Fossils of
Santa Lucia’ (Bull. Soc. géol. France, ser. 3, vol. xxiv. 1896, p. 841) :—

‘If we consider the vertical and horizontal distribution of the genus
Crypheus, we are at first sight struck by the fact that it is more especially
localized in the Coblentzian and the Hifelian. In fact, it is characteristic of
the strata of that age in the Rhenish area, and is also found in the deposits
with Hercynian facies of the Harz. On the other hand, it has not been
recorded in Bohemia in the beds above stage E. In the Ardenne Crypheus is
unknown, and in England this group is represented by only one species, quoted
and figured by Salter, which moreover appears to be a rarity. In the West of

Vol. 53. | FOSSILS FROM THE MORTE SLATES, ETC. 445»

VI. Description oF THE FossILs.
By the Rev. G. F. Warpzorne, M.A., F.G.S.

Datmanires (CrypHmus) Lacinratus, F. Romer, ? var. occi-
DENTALIS. (Pl. XXXIII. figs. 9-13.)

Locality. Oakhampton Quarry. Four heads, 5 tails.

Size. Head about 15 mm. long, 32 mm. wide. ‘Tail about
15 mm. long, 17 mm. wide. Tail-spines nearly 10 mm. long.

Description. Head wide, semi-oval, slightly lobate in front..
Glabella large, subconical, with large, tuberculate, overhanging
anterior lobe, and with three lateral lobes, of which the two
upper are rather large and subtriangular, and the lower is small and-
narrow ; furrows strong, nearly reaching to the centre. Hyes about
3 the length of the head, prominent, composed of more than 170
lenses in about 28 vertical rows of 9 or fewer lenses each. Cheek--
spines long, narrow, curved, tapering. Neck-lobe prominent. ’

Pygidium elongate, rather narrow, subtriangular, with a rather
narrow tapering axis of probably about 12 segments ; lateral lobes
with 5 strongly marked widening ribs, indistinctly bordered, and
bearing 5 very long, narrow, distant, thorn-like, nearly straight
lateral spines, and a (seemingly) rather shorter and broader terminal
spine.

; Remarks. Salter* refers to C. punctatus, Steininger,’ three
specimens from Liskeard, which chiefly differ from ours in having
smaller eyes, longer and stouter cheek-spines, and a broader tail.
Kayser,” however, tabulates the species of Crypheus in two
divisions, based on the presence or absence of a clear terminal spine.
Such a spine, according to him and other authors, is wanting in
C. punctatus ; but our specimens always have clear indications of

France, however, so soon as we come to the horizon of the Orthis Monnieri-
sandstone, Crypheus is: abundant, as also in the O. wndata-beds, while it
becomes scarcer in the Sp. Decheni-beds (=Erbray Limestone), and in the
Phacops Potieri-zone (=Grauwacké of Hierges). Again, in the Devonian of
Spain and in that of the Bosphorus, the genus Crypheus is found to occur.

‘In America, the genus Dalmanites passes up, with but little modification,.
from the Silurian into the Devonian; but, so soon as we reach the base of the
Coblentzian (Oriskany), types appear in conjunction with it which are referred
to it under the heading of subgenera, and are evidently derived from it.
Among these, Crypheus is the latest comer, and is the one which persists the
longest (up to the top of the Coblentzian). It attains its greatest development.
in the Hamilton Group, especially at the horizon of the Hamilton Shales, where
the other subgenera of Dalmanites cease to appear, and where this genus itself
is merely represented by a single species. Finally, a last survivor of the group
recurs in the Tully Limestone, that is, at the horizon of the Givetian.

‘From the foregoing facts we conclude that Crypheus is more especially
localized in the Coblentzian beds of the Rhine and the Harz, and also in those
of the West of France, Spain, and the Bosphorus (the last three are very similar
from many points of view), while in America it made its appearance later and
did not so soon become extinct..—May 15th, 1897.]

1 1864. Salter, ‘Mon. Brit. Trilob.,’ p. 59, & pl. i. figs. 17-19.

? 1834. Steininger, Mém. Soc. géol. Fr. vol. i. pt. ii. p. 356, & pl. xxi. figs. 7-7 b.-

3 1878. Kayser, Abh. geol. Specialk. Preuss. vol. ii. pt. iv. p. 33.

446 REV. G. F. WHIDBORNE—DESCRIPTION OF THE [Aug. 1897,

one, and therefore they cannot (on this basis) be identical with
C. punctatus.

On the other hand, in C. lacineatus, F. Romer’ (as also in
C. rotundifrons, Emmerich,” C. acutifrons, Schliiter,* and C. Groti,
¥, A. Romer,* which Kayser identifies with it), and still more so in
CO. Lethew, Kayser,’ the spines seem usually much shorter, closer,
and stouter than in our specimens, the terminal spine particularly
so. In C. limbatus, Schltter,° they are said to be shaped like those
of CO. laciniatus, but separated by equally wide intervals. In
C. Calliteles, Green, as figured by Hall,” they vary much, being
sometimes as stout and short as in C. laciniatus, and sometimes
more like ours; but its pygidium is much broader, and its cheek-
spines much stouter. Jf Hall, indeed, were right in referring all
his specimens to one species (a reference which Kayser questions),
the development of the terminal spine would have little specific
weight. C. laciniatus, Barrois,” seems, as suggested by himself, to
agree with some forms of C. Calliteles. Oryphceus sp., Kayser *
(identified by him with the Phacops stellifer, Burmeister, of
F. A. Romer ’°), is imperfect, but, so far as can be seen, is very like
our pygidia, except that itis broader. In Ph. stellifer, Burmeister,”
itself the tail seems broader, the terminal spine longer, and the
glabella-lobes differently arranged. C. Pleione, Hall,” appears to
be known only by a single imperfect pygidium, which looks as
though it possibly might agree with ours; Kayser has doubtfully
quoted it from Daun (Lower Devonian).

It may be noted that, while in most of our pygidia the spines
seem very acute and narrow, in one specimen they are broader and
more blade-like. Possibly this may be due to a difference in sex.

From the above comparisons it does not seem that we can identify
our fossil very certainly with any known species ; but on the other
hand the distinctions observable are not, in the state of our present
material, sufficiently pronounced to justify us in treating it at
present as a distinct species. I therefore place it provisionally as a
variety of C. laciniatus, only observing that I expect that, when
better specimens are found, it will prove to be quite as distinct
from it as are several of the various forms that are quoted above.

1 1844. F. Romer, ‘ Rheinisch. Uebergangsgeb.’ p. 82 & pl. ii. fig. 8.

2 1839. Emmerich, ‘ Dissert. Trilob.’ p. 23, fig. 1, and 1846, Burmeister,
‘Organ. Trilob.’ p. 92 & pl. iv. fig. 2.

3 1881. Schliiter, Verhandl. n. Vereins Rheiui. vol. xxxviii. p. 144.

4 1843. F. A. Romer, ‘ Verst. Harzgeb.’ p. 39 & pl. xi. fig. 11.

5 1889. Kayser, Abh. k. Preuss. geol. Landesanst., n.s., pt. i. pp. 81, 86, &
pl. xi. figs. 3, 5, 6, & pl. xxiii. figs. 7-9.

6 1881. Schliter, Verhandl. n. Vereins Preuss. ser. 4, year 8, p. 77.

7 1888. Hall, ‘Pal. N.Y.’ vol. vii. p. 45, pl. xvi. figs. 5-22 & pl. xvia.

8 1889. Barrois, Mém. Soc. Géol. Nord, vol. iii. p. 267 & pl. xvii. fig. 11.

§ 1889. Kayser, Abh. k. Preuss. geol. Landesanst., n.s., pt. i. p. 82 & pl. xi.
fig. 4.

10 1850. F. A. Romer, ‘ Beitr. z. geolog. Kenntn. d. nordwestl. Oberharz,’
pt. i. p. 62 & pl. ix. fig. 28.

11 1846. Burmeister, ‘Organ. Trilob.’ p. 97 & pl. iv. fig. 8.

12 1888, Hall, ‘ Pal, N.Y.’ vol. vii. p. 41 & pl. xvia. fig. 2.

Wol.53; FOSSILS FROM THE MORTE SLATES, ETC. 447

Datmanites sp. (Pl. XXXI. figs. 1-3.)

Locality. Treborough. Two heads, | thorax, 1 tail.

Size. A distorted head is about 15 mm. long, and 21 mm. wide.

Description. Head probably rather elongate, semi-oval. Glabella
large ; anterior lobe tuberculate, subcircular, occupying the whole
front of the head; lateral furrows short and indistinct; genal
angles apparently produced into spines of unknown but probably
considerable length. Eyes extremely large, prominent, with more
than 100 lenses in 18 vertical rows. Neck-lobe rather narrow and
Straight.

Thorax with narrow, raised axis. Pleure about half as wide
again as the axis, curved gently backward, and then slightly
recurved at the fulcrum, divided by a strong furrow.

Tail with a very narrow, tapering axis, reaching to the border,
but apparently not produced beyond it, having probably 10 or 12
ribs, each bearing a lateral tubercle. Lateral lobes with 5 or 6
furrowed ribs. Border narrow.

Remarks. The evidence given by these somewhat imperfect
. specimens is rather unsatisfactory. Though much like Phacops
Stokesia (from the Silurian) or Ph. Mushenti in general look, the
shape of the base of the head and the apparent existence of a
cheek-spine seem to show that they really belong to Dalmanites.
I do not know any German or American species of that genus
that appear to be identical with them. Some Bohemian species
approach them in the size of the eye.

Homatonotus sp. (Pl. XXXI. fig. 4.)

Locality. Treborough.

Two fragmental specimens, insufficient for specific comparison,
appear to belong to this genus. Of these one is part of the side of
a thorax, showing 8 ribs, which seem deeply and obliquely grooved
near their margins, which are straight and perpendicular, and have
signs of a tubercle near them. The other is still more indistinct,
and can only be said to have a strong likeness to an oblique view
of the side of such an animal without showing details; in it a
smooth triangular surface may represent the cheek, and there seem
to be 11 long ribs, with no defined axis, and also indications of a
distorted tail.

CypRIcARDINIA? sp. (Pl. XXXI. fig. 5.)

Locality. Treborough. One specimen.

Size. 7 mm. high, 14 mm. long.

Description. Transverse, suboblong. Upper margin very long,
nearly straight, punctated (apparently by the ends of the ribs).
Posterior margin straight, slightly oblique. Postero-inferior corner
nearly subangular. Inferior margin slightly convex, curving rapidly
in front. Anterior side only about ? the height of the posterior side.
Contour of back flattish generally, but definitely convex below.
Surface marked by 20 linear ridges, which are parallel to the rear

448 REY. G. F, WHIDBORNE—DESCRIPTION OF THE [ Aug. 1897,

margin, and turning suddenly near the inferior margin become
subparallel to it; the line through the angles thus produced forms
a concave curve from the posterio-inferior corner to the limbs.
Umbo apparently inconspicuous, situate nearly at the antero-
superior corner.

Remarks. It seems to me by no means certain that this fossil is
a lamellibranch. Itis somewhat like Leaia Leidyi, Rupert Jones,.
in shape, but has no radiating ridge. The species of Hstheria
described by Rupert Jones are all more oval, and show no sudden
bend in the striation. On the other hand, while it has a general
resemblance to Cypricardinia, the posterior slope (occupying § of
the shell) would be unusually large for that genus, and there are
no signs of its usual median constriction. The size of the slope
may, however, have been exaggerated by its compression.

It is a longer and more oblong shell than C. scalaris, Phillips, sp.

GossELetia ? Kayser1, Frech? (Pl. XXXI. figs. 6 & 6a.)

Locality. Treborough. One specimen.

Size. About 25 mm. long.

Remarks. This is a very indistinct and enigmatical fossil. It
consists of a low, convex, transversely ovoid central cast, having
some grooves at the upper corner of the broad end, and terminated
by an abrupt deflexion at the narrow end. It is bounded above by a
sharp impressed straight line, beyond which is a narrow border,
bearing numerous obliquely horizontal strize, which vanish toward
the broad end of the fossil.

Its nature is very doubtful; but a comparison of Grosseletia
devonica,, Barrois, and Myalina lodanensis, Frech,” suggests a
relationship, while Frech’s * and especially Kayser’s * figures of the
Lower Devonian G. Kayseri render it not impossible that it may be
a small specimen of that species.

Grammysia? sp. (Pl. XXXI. figs. 7-9.)

Locality. Treborough. Two specimens.

Size. A crushed and imperfect specimen is 14 mm. high by 32 long.

Remarks, Of these fossils it can only be said that they seem
transversely oval, very oblique bivalves, apparently with small
umbones and strongly curved lateral margins, and covered with
about 12 rather irregular growth-lines, which seem to vanish on the
posterior slope. They may possibly belong to Grammysia, but
there is nothing to prove that they do so, and it must be distinctly
understood that they are at present only doubtfully and provision-
ally placed under this heading for convenience.

1 1882. Barrois, Mém. Soc. Géol. Nord, vol. ii. p. 274, pl. xii. figs. 1-1 g.

2 1891. Frech, Abh. geol. Specialk. Preuss. vol. ix. pt. iii. p. 158 & pl. xv.
figs. 1-2 a,

3 Ibid. p. 126 & pl. xiii. figs. 1-3.

4 1889. Kayser, Abh. k, Preuss. geol. Landesanst., n.s., pt. i. p.18 & pl. vill-
fig. 6.

Vol.:53:| FOSSILS FROM THE MORTE SLATES, ETC. 449

AVICULOPECTEN MUNDUS, sp. nov. (Pl. XXXIII. figs. 14, 14a, 15 &
15a.)

Locality. Oakhampton Quarry. Two good, and some imperfect,
specimens.

Size. Height 25 mm., length 32 mm.

Description. Left valve moderate in size, slightly fransverso.
obliquely oval. Umbo situate at or about the anterior third of
the length, acute, slightly surpassing the hinge-line and tending
slightly Forward, Anterior wing long, narrow, triangular, acutely
pointed, and extending beyond the front of the body. Posterior
wing (very indistinctly seen) apparently nearly similar in shape,
but rather larger. Margins arching in a continuous curve, which
is deepest rearward. Surface with 40 or 50 narrow subacute
ribs, sometimes alternating, separated by rather wider concave
furrows; the whole crossed by extremely regular, close, sharp,
minute threads, which seem to undulate so as to be slightly convex
to the beak on the ribs, and concave on the furrows.

Remarks. This species is very similar to A. gracilis, Beushausen,’
but that species is more oblique, its hind wing is shorter and of a
different shape, and the transverse marks are described as irregular.
A. perovalis, Beushausen,? is less oblique, and has a much shorter
hinge-line. A. Wulfi, Frech,’ is very similar in shape and orna-
ment, except that its umbo seems blunter and more central, its
anterior notch shallower, its front wing broader, and its hind wing
apparently much larger, bringing it within the section Pterino-
pecten; both in Frech’s figures and our specimens, however, the
hind wings are badly preserved. It seems to me that our shell
cannot be identified with either of these three Lower Devonian
species, though standing midway between the first and the last.

Avicula Neptuni, Goldfuss,* is also similar, but has less acute ears,
coarser transverse striz, and apparently a longer hinge-line.

LrorTera sEMIRADIATA, Frech. CPI, XXXL,’ fies. 1, ay. 2: &
2 a.)
1889. Péerinea aff. lineata, Kayser, Abh. k. Preuss. geol. Landesanst., n. s., pt. i.
p. 21 & pl. vii. fig. 2
1891. Limoptera semiradiata, Frech, Abh. geol. Specialk. Preuss. vol. ix. pt. iii.
p. 65 & pl. v. figs. 1-3, 5-8.

Locality. Oakhampton. Two specimens.

Size. Length and height, about 40 mm.
These obscure specimens, one of which is much crushed and the

' 1884. Beushausen, Abh. geol. Specialk. Preuss. vol. vi. pt. i. p. 54 & pl. ii.
fig. 5.

2 Ibid. p. 53 & pl. ii. fig. 6.

8 1891. Frech, Abh. geol. Specialk. Preuss. vol. ix. pt. iii. p. 25 & pl. ii.
fig. 7.

* 1834-40. Goldfuss, ‘ Petref. Germ.’ vol. ii. p. 125 & pl. exvi. fig. 4.
GO. d7Gas. No, 211. 2H

450 REY. G. F. WHIDBORNE

DESCRIPTION OF THE [ Aug. 13897,

other much blurred, appear to agree with figures of a right (?) and
left valve of Frech’s species. The wings look smaller, but are
probably very defective. The surface of one specimen seems
covered with very numerous minute flexuous and irregular rays
(cf. Frech, fig. 2); in the other the ribs are fewer and stronger, and
the transverse lines scalloped (cf. Frech, fig. 6). In both I think
I can detect, though very doubtfully, the peculiar characteristic
shape of Limoptera. ‘The ornament of the first of the two speci-
mens is very like that of a Daleiden specimen of the left valve of
Pt. lineata’ lent me by Mr. Upfield Green. In that species,
however, the right valve is said to be smaller. L. semiradiata is
said to be frequent in the Lower Coblentzian of St. Johann (Hifel).

Sprrirera sp. (Pl. XXXI. fig. 10.)

Locality. Treborough.

Size. 17 mm. wide. Area about 5 mm. wide.

A single fossil shows a wide, slightly concave area, with a
triangular fissure, bounded apparently by strong dental plates. Its
valves are almost destroyed by compression, but they evidently had
strong ribs, of which there are indications of at least 3 or 4 on each
wing and possibly of 3 or 4 on the fold.
lt From the appearance of its area it might very possibly be a
specimen of Sp. subcuspidata, Schnur,? but it is far too poor to be
identified.

Sprrirera sp. (Pl. XXXIV. fig. 3.)

Locality. Oakhampton Quarry.

The ventral valve of a spirifer occurs lying on an elongate
decayed organism, which is either the continuation of its hinge-line
or more probably one of the enigmatical aciculate bodies that are so
common at Treborough. Its umbo is low and incurved ; its shape
transverse, subfusiform, and probably acutely alate ; its sinus rather
broad, with an indication of a minute median rib. On each side
are about 6 strong, sharpish, distant ribs, which seem separated by
broad concave furrows. The surface seems crossed by very distant,
regular, transverse lines. Thus it is not unlike Spircferina cristata,
var. octoplicata, Sowerby, but the specimen is much too indistinct
and obscured by clothing matrix to be identified. As it lies, it
presents a striking likeness to a figure by Kayser’ of a broken
specimen of Spirifera Hercynia, Giebel.*

1 1834-40. Goldfuss, ‘ Petref. Germ.’ vol. ii. p. 1385 & pl. exix. fig. 6.

? 1852. Schnur, Palzontographica, vol. iii. p. 202, pl. xxxiii. fig. 3 a-f &
pl. xxxiv. fig. 1 a-g.

3 1878. Kayser, Abh. geol. Specialk. Preuss. vol. ii. pt. iv. p. 168 & pl. xxiii.

fig. 11.
4 1858. Giebel, ‘ Sil. Faun. Unterharz,’ p. 30 & pl. iv. fig. 14.

Vol. 53. | FOSSILS FROM THE MORTE SLATES, ETC. 451

RuyncwHonetta sercynica, Kayser? (Pl. XXXIV. figs. 4, 4a,
4b & 5.)

Locality. Oakhampton. Four specimens.

Size. Probably about 14 mm. in width and length, and 7 mm. in
depth. :

Description. Shell suborbicular, rather flattened. Umbo rather
elevated, incurved. Area large, slightly concave, with defined
edges. Dental lamelle strong. Fold and sinus low, wide,
probably arching. Ribs strong, numerous, reaching to the umbo,
transversely plaited, numbering about 7 on the fold, 6 on the sinus,
and 8 or 9 on each side.

This seems to belong to the group of Rh. plewrodon, but differs
from the Upper Devonian members of that group in the much greater
number of ribs on its fold. In that respect it approaches Fh. llando-
veriana, Davidson,’ but its dental lamelle are placed much nearer
together, and it does not seem to have the serrations, described by
Davidson, on that shell. None of Schnur’s species approach it.

- In its crushed condition the shape of its foid is obscured, but if,
as seems possible, it was gently arched, it might be referred to
the Lower Devonian 2h. hercynica, Kayser, which, in the number
of ribs and other characters, it seems to approach.

RHYNCHONELLA NyMPHA, Barrande? (Pl. XXXIV. figs. 6 & 7.)

Locality. Oakhampton Quarry. ‘Three specimens.

Size. Apparently something like 25 mm. wide by 20 mm.
high.

This form seems distinguished from the preceding by its larger
size, by its fewer and stronger ribs, and by its more extended sinus
bearing fewer ribs. It appears to be common, but in Dr. Hicks’s
collection is represented only by very fragmental specimens.

Its fold appears to have been somewhat elevated, flattened, and
considerably extended in front, and to have borne either 5 or 6
strong ribs, while there were probably about 7 smaller ribs on each
side. The ribs are very acute and elevated, extend quite over the
umbo, and sharply interlock at the margins.

So far as can be seen in their defective state, our specimens
accurately agree with the figures of Rh. nympha, Barrande,’ given
by Kayser [from Lower Devonian shells|.*| While from their
evidence it cannot be said to be identical, so far as that evidence
goes it is indistinguishable from them.

1 1869. Davidson, ‘ Brit. Foss. Brach.’ vol. iii. p. 184 & pl. xxiv. figs. 8-13.

? 1878. Kayser, Abh. geol. Specialk. Preuss. vol. ii. pt. iv. p. 153 & pl. xxv.
figs. 9-1].

3 1847. Barrande, ‘ Naturw. Abhandi.’ vol. i. p. 422 & pl. xx. figs. 6-8; and

1879. Barrande, ‘ Syst. Sil. Bohéme,’ vol. v. pl. xxix. figs. 10-18, etc., Etage F.

4 1878. Kayser, Abh. geol. Specialk. Preuss. vol. ii. pt. iv. p. 142 & pls. xxv.
figs. 1, 2, 6-11, xxvi. figs. 15-18.

2H 2

452 REY. G. F. WHIDBORNE—DESCRIPTION OF THE [ Aug. 1897;

From Rh. daleidensis, F. Romer,' or Rh. livonica, von Buch, SPog-
it seems to differ by the greater number of ribs on its fold.

STROPHEODONTA THNIOLATA (Sandberger). (Pl. XXXIV. figs. 8 & 9.).

Locality. Oakhampton Quarry. Three specimens.

Size. About 20 mm. long by 22 wide.

Description. Semi-oval, flattish ; width nearly if not quite equal’
to length; apparently geniculate near the margins. Hinge-line
equal to greatest length, straight, bearing on the margin a series of
serrations fitting into those of the opposite valve. Muscular
impressions rather small, cordate, radially striated (?), bounded
by raised margins and divided by a median ridge. Pallial region
strongly papillose within. Surface covered with very numerous:
fine rays, between each of which there appear to have been possibly
several still finer.

Remarks, With its serrated hinge and probably double system of
strie this shell seems akin to Stropheodonta (Leptena) interstrialas,
Phillips, sp.,*° but may, I think, be distinguished by its greater size,.
less transverseness, etc. Where so few characters are seen it is
difficult to point out distinctions, but the general impression which.
it conveys seems different from that of Lummaton examples of
Phillips’s shell. From the Lower Devonian (Daleiden) fossils,
however, figured by Schnur * under the same name, it does not seem.
separable. Strophomena tenolata, Sandberger,’ from the Spiriferen-
sandstein of Daleiden, etc., seems also almost exactly alike, his.
figures differing only in being slightly longer and in having rather
large muscle-scars. With this shell Sandberger unites St. Phillipsi,.
Barrande © (which Barrande compares with St. interstrialis), but
in it the serrations on the hinge are much finer and the shape
more spherical. St. imbrex, Pander,’ differs internally, while
St. euglypha, Sowerby,*® has the ventral valve concave instead of
convex.

STROPHOMENA (SrroPHEopoNTA ?) uexpLanata (Sowerby)? (PL..
XXXI. figs. 11-13, & Pl. XXXII. figs. 1-3.) |

Locality. Treborough. Numerous specimens.

Size. One specimen (elongated) is 80mm. long by 60 mm.
wide ; another (widened) is 50 mm. long by 100 mm. wide.

Description. Very large, apparently nearly flat, perhaps rather
longer than wide. Umbo slightly produced. Hinge-line as long

* 1844. F. Romer, ‘ Rhein. Uebergangsgeb.’ p. 65 & pl. i. fig. 7.

* 1834. Von Buch, ‘ Ueber Terebrat.’ p. 37 & pl. ii. fig. 380 a-c.

> 1841. Phillips, ‘ Pal. Foss.’ p. 61 & pl. xxv. fig. 103.

* 1853. Schnur, ‘ Hifel Brach.’ p. 222 & pl. xli. figs. 2 a-f.
, ° 1856. Sandberger, ‘ Verst. Rhein. Nassau,’ p. 360 & pl. xxxiv. figs. 11-11 c,.
Etage F.

§ 1847. Barrande, ‘ Naturw. Abhandl.’ vol. ii. p. 226, pl. xxi. figs. 10-11.

7 1871. Davidson, * Brit. Foss. Brach.’ vol, iii. p. 286 & pl. xli. figs. 1-6.

§ 1871. Lod. p. 288 & pl. xl. figs. 1-5.

Vole 53.] FOSSILS FROM THE MORTE SLATES, ETC. 453

-as the width of the shell. Hinge-area narrow, slightly triangular,
with fine crenulations on the proximal margin. Margins curving
‘slightly on the sides and more rapidly in front. Surface covered
with between 150 and 200 fine straight elevated striz, divaricating
at rather regular intervals, separated by somewhat wider furrows,
and crossed by a few strong growth-lines, and by very numerous
fine threads, which on portions of the specimens give rise to minute
radially-arranged slits (possibly due to these threads becoming
foliaceous on the strie).

Remarks, Some of the specimens are magnificent, but unfortu-
nately their critical characters are much obscured. It may be noted
(1) that in one or two specimens there seems the appearance of a
slight median fold, which, however, is probably due only to
accidental causes; (2) that the ribs are extremely regular, though
occasionally a stronger one occurs, and there are no signs of a minor
intermediate series; (3) that on the wings where longitudinal
Strain has occurred the transverse marks are represented by
radiating scalariform rows of exceedingly regular slits, abruptly
ended; (4) that while in all the specimens the hinge is very
defective, one seems to have crenulations which indicate that it is a
Stropheodonta, and another shows a definitely triangular though very
narrow area, while one or two others show short umbonal grooves
on crural ridges set at right angles to each other, and extremely
indistinct signs of a rather large muscular area ; and (5) that while
nearly every specimen has lost its true shape, a small one, which
seems to have retained it, is nearly square.

Several equally gigantic forms occur in the Lower Devonian
of other localities. St. gigas (M‘Coy),* from Looe, is at once
distinguished by its numerous minute minor ribs between the
major series. M‘Coy describes the ribs of that species as separated
by punctured lines, while Davidson mentions that in Streptorhynchus
umbraculum (which is similarly distinguished by its minor ribs)
“the ribs are crossed by scale-like strive, while the interspaces are
crossed by finer and more numerous lines of growth.’

Strophomena Steini, Kayser,” equals ours in size and apparently
in shape, but its ribs seem fewer, wider apart, and more arching
laterally (the latter character being apparently regarded by Kayser
as of specific value). |

On the other hand, I find nothing to separate our shells from
St. explanata (Sowerby),*? which is also figured by Kayser * from

1 1852. M‘Coy, ‘ Brit. Pal. Foss,’ p. 386 & pl. iia. fig. 7.

2 1889. Kayser, Abh. k. Preuss. geol. Landesanst., n. s., pt. i. p. 103 &
pl. xii. fig. 1.

$ 1842. Sowerby, Trans. Geol. Soc., ser. 2, vol. vi. pt. ii. p. 409 & pl. xxxviii.
fig. 15.

4 1889. Kayser, Abh. k. Preuss. geol. Landesanst., n. s., pt. i. p. 102 &
pls. xxi. figs. 1-3, xxii. fig. 1. He says: ‘St. explanata is known to me from all
the beds of the Rhenish Lower Devonian...... and is nowhere particularly
rare.

454 REV. G. F. WHIDBORNE—DESCRIPTION OF THE [ Aug. 1897,

the Lower Devonian. It agrees in size and ribbing, and, so far as
can be seen, in internal arrangement. Again, St. subarachnoidea (de
Vern.), is very similar and may be identical, but is much smaller
and appears to be a more recurved shell. Kayser distinguishes:
St. explanata from it only by its greater size, flatness, and width.
Orthis spathulata, F. A. Romer,’ is described as having broad ribs:
and narrow furrows, but Orthis aff. spathulata, Quenstedt,? which
is identified by Kayser* with St. gigas (M‘Coy), more nearly
approaches the present form. ; :

‘ STREPTORHYNCHUS ? PERSARMENTOSUS (M‘Coy).’ (Pl. XXXII. figs. 4
& 5.)

Locality. Treborough. ‘Two specimens.

Size. About 10 mm. long by 25 mm. wide.

Two very imperfect specimens accurately agree with M‘Coy’s.
figure,’ except that they are rather smaller and not quite so wide.
They show the same coarse, ramose, median and fine, straight, lateral
ribs. M‘Coy describes this shell as common in the Lower Devonian
of Fowey, Looe, etc., and he gives a very similar species, Orthis
sarmentosa,® from the Bala Beds.

Davidson, however, is evidently disinclined to regard these as a
true species; and our examples almost certainly seem to owe their
peculiar character chiefly to distortion. In recording it, therefore,
I do not suggest that St.? persarmentosus is a true species, but
simply that our shells are identical with M‘Coy’s and must stand or
fall with it. It may be noted that one of our examples of Stropheo-
donta explanata shows the same peculiarities in an incipient
degree.

CHoNETEs PLEBEIA, Schnur. (Pl. XXXIII. figs. 1 & 2.)

[Of this species Cthlert says (Bull. Soc. géol. France, ser. 3,.
vol. xl. p. 519: ‘The vertical range of Oh. sarcinulata is much
greater than that of Ch. plebeia, which is observable particularly in
the inferior beds of the Devonian Limestone, where sometimes this -
species occurs almost exclusively.’ |
_ Locality. Treborough. Common.

Size. About 5 mm. long by 8 mm. wide.

Description. Shell very small, slightly transverse, semi-oval.

1 1842. D’Archiac & de Verneuil, Trans. Geol. Soc., ser. 2, vol. vi. pt. ii.
p. 872 & pl. xxxvi. fig. 3; and 1889. Kayser, Abh. k. Preuss. geol. Landesanst.,.
n.5., pt.i. p. 10] & pl. xix. figs. 1-2 a. '

21852. FA. Romer, ‘ Beitr. Harzgeb.’ pt. ii. p. 98 & pl. xv. fig. 2.

3 1871. Quenstedt, ‘ Petref. Deutschl. (Brachiop.)’ p. 583 & pl. lvi. figs. 53,
54.

4 1890. Kayser, Jahrb. k. Preuss. geol. Landesanst. p. 101 & pl. xiii.
figs. D2,

5 1852. M‘Ooy, ‘ Brit. Pal. Foss.’ p. 385 & pl. ii a. fig. 9 ; and 1865. Davidson,
‘ Brit. Foss. Brach.’ vol. iii. p. 84 & pl. xvi. fig. 5.
§ 1871. Davidson, ‘ Brit. Foss. Brach.’ vol. iii. p. 262 & pl. xxxvi. figs. 35-38~

Vol. 53. ] FOSSILS FROM THE MORTH SLATES, ETC. 455

Hinge-line as long as the width, bearing a few large, obliquely-set,
arching spines. Surface with 40 or 50 coarse, rounded, close rays,
which have increased by intercalation at various distances from the
umbo. Interior of ventral valve with two strong grooves, reaching
more than halfway forward, and with several coarse punctations.
Lateral margins slightly alate where they join the hinge-line.

Remarks, The ribs are coarsely granulate as seen on the inside of
the dorsal valve, and are crossed by fine regular concentric threads.
Our shells appear to agree accurately with Ch. plebeia as described
by Schnur? and Cshlert * as well as by Kayser,’ who first united it
to Ch. sarcinulata, Schloth., but afterwards,* following Céhlert, again
separated it.

At Treborough it seems to have been gregarious, occurring
abundantly in a different part of the quarry from that which has
yielded Ch. sarcinulata and most of the other fossils.

CHONETES SARCINULATA, Schlotheim, sp.? (PI. XXXIII. figs. 3-5.)

[Géhlert, Bull. Soc. géol. France, ser. 3, vol. xi. p. 520, remarks:
‘This species, whose geographical extension is very great, is
characteristic of the Lower Devonian.’ |

Locality. Treborough. Eight specimens.

Size. Length 11 mm., width 16 mm.

Description. Shell small, transverse, semi-oval. Hinge-line showing
a double area and a triangular fissure, and bearing a few rather
large, obliquely-set, arching spines. Muscular area large, heart-
shaped, with a median sinus. _ Surface covered with very numerous
minute radiations.

Remarks. These specimens appear to agree with the various
figures of Ch. sarcinulatu,’ except that they seem less oblong and
perhaps not quite so transverse, and that the front margin is more
curved than usually appears in that species. It is, however, quite
possible that the latter difference may be simply due to crushing
and flattening. The size of the ribs seems to vary considerably,
two of the specimens having much coarser ribs and thus approaching
Ch. plebeia. On the other hand, our typical specimens are quite
different from the much smaller shells from this quarry above
referred to Ch. plebeia, and it is possible that these two aberrant
specimens, which are very indistinct, may belong to neither species
or not even to the genus Chonetes at all.

' 1854. Schnur, Paleontographica, vol. iii. p. 226 & pl. xlii. fig. 6.

2 1883. Ciblert, Bull. Soc. géol. France, ser. 3, vol. x1. p. 517 & pl. xiv. fig. 3.

* 1878. Kayser, Abh. geol. Specialk. Preuss. vol. ii. pt. iv. p. 200 & pls. xxx.
figs. 13, 14?, xxxiv. fig. 9.

1 1889. Kayser, Abh. k. Preuss. geol. Landesanst., n.s., pt. i. p. 63 & pls. vii-
fies. 2-5, x. fig. 7.

"5 1820, Schlotheim, ‘ Petrefact.’ p. 256 & pl. xxix. fig. 3.

456 REV. G. F. WHIDBORNE—DESCRIPTION OF THE [Aug. 1897,

Ch. sordida (Sowerby)! will, I expect, probably prove to be a
synonym of Ch. sarcinulata.
Ch. tenuicostata, Othlert,” seems distinguished by its much more

erect spines.

Crinoid-remains.

Locality, Oakhampton.

Fragmentary grouped stems occasionally occur. In one specimen
are seen several minute rootlets of five or six joints grouped round
these stems, but they are too vague to give definite character.

Crinoid-segment.

Locality. Treborough. Limestone above the slate-quarry.

A single segment is in a good state of preservation. It is cireular,
rather short, with a periphery formed by the revolution of a vertical
semicircle. The articulating surface is concave, bounded by an
impressed circular line, within which are 33 impressed radii about
the central channel, which appears to be in the form of a four-
pointed star.
Sponge-spicule.,

Locality. Treborough. Limestone.

Size. Fragment, 2 cm.

A minute fossil, apparently a spicule, is on the same slab as the

above-named crinoid-segment. It consists of six rods in one plane,
meeting in a focus from which a seventh rod rises perpendicularly.

CuapocHonus? (Pl. XXXIII. fig. 8.)

Locality. Treborough.

Size. 30 or 40 mm.

Two specimens of free-branching organisms of small size appear
to me to belong to this genus, but, being in their state of preserva-
tion, little more than elongated cylinders or cones, which seem at
intervals to thicken and divaricate into two or more branches the
length of which cannot be traced, it is impossible to decide their
nature. They seem less regular than most species of Cladochonus,
but they may be compared with C. Schliuteri, Holzapfel,? which
appears to present a similar irregularity.

Prrrara sp. (Pl. XXXIII. figs. 6, 6a & 7.)

Locality. Treborough. Four specimens.

Size. About 20 mm. high, 15 mm. wide.

Description. Cup irregularly conical, small, rather elongate.
Septa 19 or 20, thin, smooth. No tabule or developments. One

1840. Sowerby, Trans. Geol. Soc., ser. 2, vol. v. pt. iii. pl. liii. fig. 5.

? 1883. Gihlert, Bull. Soc. géol. France, ser. 3, vol. xi. p. 515 & pl. xiv. fig. 2.

° 1895. Holzapfel, Abh. k. Preuss. geol. Landesanst., nu. s., pt. xvi. p. 305 &
pl. xvi. figs. 1, 2, 4, 5, 7. ,

Vol. 53. ] FOSSILS FROM THE MORTE SLATES, ETC. 457

(or perhaps more) septal fossule. Secondary septa rudimentary,
hardly indenting the interseptal spaces in the cast. Reproduction
from the outside margin of the cup. Base dilate.

Remarks. This species is represented by casts and natural
sections. I do not think that it is identical with either of the
forms described by Phillips.

ERImDoPHYLLUM sp.

Locality. Treborough.

Size. About 80 mm. long.

Description. Coral composite, free, growing from a single original
in a series of calicularly-produced cups, which swell out into nodes
at rapid intervals. Epitheca apparently thick. Septa few, strong,
and apparently short, only reaching part way to the centre. Dis-
sepiments few and coarse.

This fossil, which was found by Mr. R. 8. Herries, Sec.G.8., has
perplexed me much, as its details of structure are only partially ex-
posed in the only specimen. It appears to me that in all probability
it belongs to the Devonian (America) and Silurian (Gothland) genus
Eridophyllum of Milne-Edwards and Haime, though whether its
swellings possess the root-like character of those of that genus is
not yet clear.

EXPLANATION OF PLATES XXXI.-XXXV,
Puate XXXII.
Treborough Slate-quarry.

Figs. 1-3. Dalmanites sp. 1. Head, nat. size. 2. Cast of the reverse of 2a.
3. Pygidium, nat. size.
Fig. 4. Homalonotus sp.
5. Cypricardinia? sp. X2. ;
6. Gosseletia? Kayseri, Frech? 6a. Portion x3 showing the oblique
lineation.
Figs. 7-9. Grammysia? sp.
Fig. 10. Spirifera sp. A compressed specimen showing a wide area.
Figs. 11-13. Strophomena (Stropheodonta?) explanata (Sowerby)? 12. A small
specimen which has apparently escaped distortion.

Prats XXXII.
Treborough Slate-quarry.

Figs. 1-3. Strophomena (Stropheodonta?) explanata (Sowerby)? Variously
distorted.
4&5. Streptorhynchus persarmentosus (M‘Coy), X2. 4. From Mr. Up-
field Green’s Collection.

Puats XXXITI.
Treborough Slate-quarry.

Figs. 1 & 2. Chonetes plebeia, Schnur, X2. 1. Showing hinge-spines.
3-5. Chonetes sarcinulata, Schlotheim, x2. 4&5. Showing hinge-spines.
5. With coarser ribs than usual.
6, 6a, 7. Petraia sp. 6, 6a. Opposite views of a flattened cast. 7. Cast
seen from below; from Mr. Herries’s Collection.
Fig. 8. Cladochonus sp.

458 DR. H. HICKS ON THE MORTE SLATES, AND [| Aug. 1897,

Puate XXXITI. (continued).
Oakhampton House Quarry.

Figs. 9-13. Dalmanites (Crypheus) laciniatus, F. Romer ?, var. occidentalis.
11, 12. Pygidia showing the terminal spine and the long thorn-like
lateral spimes separated by wide intervals. 13. Rather more than half
the margin of a pygidium with rather broad and closer (but still not
contiguous) spines. The lowest spine but one is probably the ter-
minal spine.

14 & 15. Aviculopecten mundus, sp.nov. 14a & 15a. Portions of surface
enlarged, showing the transverse ornament.

PuatEe XXXIV.
Oakhamptcn House Quarry.

Figs. 1 &2. Limoptera semiradiata, Frech? l1a,2a. Portions x38 to show the
ornament of the opposite valves.
Fig. 3. Spirifera sp., showing the umbonal portion of the ribs adjacent to an
elongate body of doubtful character.
Figs. 4 & 5. Rhynchonella hercynica, Kayser? 4 is twice nat. size.
6&7. Rhynchonella nympha, Barrande? (The best fragments of this shell
are too imperfect to convey any idea of it in a drawing.)
8 & 9. Stropheodonta teniolata (Sandberger). x2.

Puate XXXY.

Geological Map of a portion of West Somerset, on the scale of
2 miles to the inch.

Discussion.

Mr. Erurriver could not agree with the Author of the paper
upon the important question at issue, either as to the stratigraphical
or paleontological evidence afforded by the Morte Slates justifying
the assertion that they are ‘ the oldest rocks in North Devon’; and
he differed entirely from the Author in the conclusions drawn, as
based upon this assertion. No proof has been shown for the
attempted change in the stratigraphical position of the Morte Slates
either in North Devon or West Somerset, the eastern (or West
Somerset) extension of the North Devon Morte Beds being only a
continuity of the same set of glossy or slaty beds from Mortehoe to
the quarries at Oakhampton, and its apparently rich Devonian
fauna, 40 miles distant. The few fossils obtained by the Author
from the western part of the Morte Series were said to be Silurian,
but close examination shows them to have been wrongly identified.
This somewhat hasty determination gave rise to the view that the
Morte Beds must or should be assigned to the Wenlock Group of the
Upper Silurian, and that as a consequence of their stratigraphical
position they should be regarded as the oldest rocks in North Devon,
interstratified in the Middle Devonian Series. No attempt has now
been made by the Author to establish, or even suggest, how or
whence this 40 miles of faulted area, between the Ilfracombe and.

Vol. 53.| ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET. 459

Pickwell Down Series, was derived, it being sufficient to announce it
on the assumption of doubtful fossil evidence. If these Morte Slates
are the oldest rocks in North Devon, it is incumbent upen those who
assert the fact to show clearly by good evidence that such inter-
polation took place, and whence and how derived; but no evidence
exists of the asserted thrust-faults over this part or in any of the
northern or eastern rocks or areas of North Devon. The great red
sandstone series and limestone-beds of Ilfracombe, ranging from
Mortehoe to Hangman Point, show no evidence of thrust-faults,
however great their foldings. There is as yet no proof in the Morte
Group of passage-beds between Silurian and Lower Devonian, either
on the dip or strike. Sedimentation along this strike of the Morte
Beds of North Devon and West Somerset for 40 miles may readily
be misunderstood, and very difficult to determine; numerous enough
have been the traverses across the so-called thrust-fault on the
north side of the Morte line of fault, and also the less faulted beds
upon the South or Pickwell Down side. These traverses have not
yet shown any affiliation of Silurian species with those in the
Morte Series. The assertion, therefore, that ‘the position now
given to the Morte beds removes one of the greatest
difficulties experienced by previous writers in their
attempts to correlate the strata in North Devon’
has yet to be proved. Again, the assertion that ‘the diversity
of fossils in the Morte Slates belonging to several
horizons as low as the base of the Upper Silurian,
added to the stratigraphical evidence, enables us
to speak with confidence as to their place in the
North Devon succession, has yet to be determined.

Prof. Hueues thought that the point which the Author wished to
emphasize was that there was in the area described an anticlinal
carrying newer beds beionging to the Devonian Series over an axis
of rocks belonging to an older part of the same series; this structure
confirming the view previously advanced by the Author, that there
was a fold of Devonian rocks stretched unconformably over a ridge
of Silurian farther west at Mortehoe. These two sections showing
a different sequence could certainly be reconciled on the hypothesis
that along the belt of country indicated by the area referred on the
older maps to the Morte Slates there was an anticlinal, the axis of
which sloped to the east, thus bringing on the newer beds in that
direction in a succession of half-spoon shaped folds. And he was
willing to build this golden bridge for his friend Dr. Hicks.

The evidence for the Silurian upfold he had already criticized,
and he would only add that all his subsequent examination of
specimens had confirmed the views which he then expressed. The
particular traverse now exhibited by the Author in support of his
contention showed a fault at either end, at the junction of the up-
thrust part of the Series with the supposed overfolded newer beds.
He did not think there was reason for believing that the throw in

460 DR. H. HICKS ON THE MORTE SLATES, AND [Aug. 1897,

the two bounding faults was great, but that it was rather one of those
very common cases in which a displacement was observed along the
junction when two rocks of different compressibility and ductility
were contorted together. Hence the theory almost involved the
idea that the beds on the north usually referred to the Ilfracombe
and Hangman stages must be the same as those on the south which
were in the old nomenclature spoken of as the Pickwell Down and |
Baggy Beds. He considered, therefore, that although the lithological
characters might enable us to discriminate between the various
subdivisions in the field, the real question before them, namely, the
relative age of the beds in the medial belt and the beds on either
side of it, was chiefly paleontological, and he thought that, taking
into account the difference of sediment and other circumstances
which tend to modify the distribution of life, no sufficient
evidence had yet been offered to establish the Author’s principal
contention.

Mr. Marr remarked that the Devonian system had been founded
on stratigraphical grounds by Sedgwick and Murchison, on paleeon-
tological grounds by Lonsdale and Etheridge. Dr. Hicks had
re-opened the question, and as the speaker had doubted the convincing
nature of the proofs brought forward by the Author in favour of
the Silurian age of some of the Morte Slates, he felt it only due to
him to state that he thought the fauna exhibited was a Lower
Devonian one, and therefore that the Author had established one
of his main contentions, namely, that the apparent succession in
North Devon was not the true one.

The Rev. H. H. Wrnwoop remarked that whatever difference may
exist in the two. views as to the stratigraphy of the North Devon
beds, yet one fact was indisputable, that the Author had found fossils
in the Morte Slates which previous observers had failed to do.
Whether the fauna proved to be Silurian or Lower Devonian, the
evidence so far showed that these slates could not be an upward
succession of the Middle Devonian or Ilfracombe Beds. During his
last visit to this district in company with the Author he was much
impressed with the enormous folding and disturbance which those
rocks had undergone, thereby very much reducing their estimated
thickness, as the late Prof. Jukes had stated.

Mr. R.S. Herriss said that he had been over part of the area with
the Author. He had not examined the south side, but he thought
that on the north there could be no doubt that on stratigraphical
grounds the Treborough Slates belonged to a series entirely distinct
from the beds immediately north of them. The exact age of these
slates was of minor importance. ‘The real point was whether they
were older or younger than the beds to the north. If the paleeonto-
logical evidence showed that they were older, as the Author con-
tended, then the inference was a very strong one that the Morte
Beds of North Devon, where the fossil evidence was not nearly so
convincing, were also older than the Ilfracombe Beds to the north

Vol. 53.] ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET. 461

of them. From the fact that so many fossils had been obtained at
Treborough in a comparatively short time, the speaker thought that
the fauna might be largely extended by anyone who had time to
work the quarries systematically.

Dr. J. W. Gregory said that he would refer only to the paleonto-
logical questions, and not to the stratigraphical difficulties. The
case for the Lower Devonian age of the fauna appeared, from the
evidence quoted by the Author, to rest on the Crypheus (as the
Author preferred to call it) lacintatus. Dr. Hicks described this
species as characteristically Lower Devonian ; but it is commonest
at the extreme top of the Lower Devonian, as in the Vichtian Beds,
where it is associated with Middle Devonian forms. Gosselet quotes
it from the Eifelian (Middle Devonian), and asserts its occurrence in
the Upper Devonian. Hence the speaker doubted whether it proved
much. He asked in what sense the Author used the names Dalmanites
and Crypheus, as they were regarded, at least by some American
authors, as synonymous—Crypheus, the name given by Green in
1837, having been abandoned owing to its prior use for a genus of
beetles. He doubted whether the absence from Oakhampton and
Treborough of species found in the beds to the north and south was
of the value that the Author assigned to it. The great difficulty in -
Devonian correlation always had been the appearance of groups of
species most characteristic of one horizon at a considerably lower
level. For example, the Brilon Ironstone has been shown by Kayser
to belong to the Middle Devonian with an Upper Devonian colony.
Hence the speaker doubted whether a list of genera such as the
Author had read was sufficient to prove whether the Oakhampton
beds were Lower or Middle Devonian. He was surprised to hear
the species punctatus spoken of as only a variety of ‘ Crypheus’
laciniatus. He was also surprised to hear the name Petraia
introduced into serious work: Petraia was a paleontological dustbin,.
into which indeterminable casts of all sorts of simple Palxozoic
corals were thrown.

The AvrHor said that as no facts had been given in the discussion
which could in any way affect his conclusions, a reply was hardly
necessary. He would, however, state that it seemed to him strange
that those who were opposed to his amended reading of the suc-
cession in North Devon and West Somerset had not visited those
areas in the interval which had taken place between the reading of
the two parts of his paper. They had been made aware of the fact
that the Morte Slates, previously considered unfossiliferous, con-
tained several faunas; and if they believed that faunas were of any
value in defining the age of the beds, they ought to have produced
paleontological evidence to refute his arguments. It was entirely
erroneous to state that any evidence had been given which tended
in the least degree to minimize his statements in regard to the
Silurian facies of the North Devon fossils or of the individual
fossils which he had described. It was quite useless here, as in

462 THE MORTE SLATES AND ASSOCIATED BEDS. [ Aug. 1897,

other areas, to cling to the belief that previous observers could
not have made a mistake: it was enough to say that they, at least,
had not the advantage of seeing the new evidence which he and
his friends who were working with him had obtained. He did not
read in detail the descriptions of the species, as he thought that it
would be sufficient to mention some of the most characteristic forms
which elséwhere are supposed to mark fairly distinct zones. ‘There
was, in his opinion, a gradual passage from the Silurian rocks of
North Devon to the Lower Devonian Beds of West Somerset, and it
was interesting to find Dalmanites and Homalonotus (characteristic
Silurian genera) in ti e latter, in association with well-known Lower
Devonian fossils. The beds on the north side, previously supposed
to be older than these, are separated from them by faults and
contain typical Middle Devonian fossils.

Quart. Journ: Geol see, Vol. LU PRAT,

F.HMichael del.et lth. Mintern Bros .imp.
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Quart. Journ .Geol.Soc.Vol -LIL.Pl XXXII.

Mintern Bros.imp.

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Quart. Journ.Geol.Soc Vol. LIT.P] XXXII.

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Quart. Journ. Geol. Soc. Vol. LIII. Pl. XXXV.

GEOLOGICAL MAP

OF A PORTION OF

WEST SOMERSET.

Scale: tinch = 2n2les.

Pilton Beds. Nowy Beds. G LowerCulm Measures
Baggy and Pickwell Trias. [ Fossil

Lifracombe Beds. @ Locahitiesin so-called

wma Faii/ts.\Alorte Slates.
Brendon fill Beds

Oakhampton Beds \ So-called Morte Slates
Treborough Beds j of II* Somerset.

CITT NTE
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Lath i o11g 1444 14,
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APA “th, 44
COLD 4G 14744

epression between Whitefield and Maundown. ]

Quart. Journ, Geol, Soc. Vol. LITT. Pl. XXXV.

GEOLOGICAL MAP

OF A PORTION OF
WEST SOMERSET.
niles.
>i WV orer Cul Measures

BS a

Vol. 53.] PLEISTOCENE PLANTS FROM CASEWICK, ETC. 463

32. Puiststocene Prants from Casewick, SHACKLEWELL, and Grays.’
By Crement Rei, Esq., F.LS., F.G.8. (Read June 23rd,
1897.)

In the year 1888, during a visit to Sir J. Prestwich, I had the
opportunity of examining his Pleistocene collection. I saw among
the specimens two lumps of clay which had been collected at Case-
wick and at Shacklewell, to illustrate papers by Morris and by
himself. These he kindly permitted me to take away and examine,
and out of them I obtained the plants mentioned below. In
Prestwich’s collection I observed also a number of plant-remains
from Grays, which had been partially determined in 1861 by Gaudin
and Heer. These, however, | was unable at the time to study, for
Prestwich informed me that he was then engaged on a paper in
which the deposits at Grays would be described. He died without
completing the work, and his collection was given to the Natural
History Museum, Lady Prestwich informing Dr. Woodward and
myself that it was Sir Joseph’s request that I should complete the
examination of his Pleistocene plants. In this manner it happens
that I am now writing a botanical supplement to papers which
were read before the Society at such distant dates as 1853, 1855,
and 1869.

Casewick (Lincolnshire.)

The alluvial deposit at this locality was described by the late
Prof. John Morris, who gave to Prestwich the lump of clay from
which I obtained the plants. There is nothing in the list to throw
any light on the age of the deposit, and so far as the flora shows
it may be of extremely recent date :—

Nuphar luteum, L.

Galium Aparine, L.
Atriplex patula, L.

Rumex crispus, L.
Ceratuphylium demersum, L.
Scirpus lacustris, L.

‘ Shacklewell (Middlesex).

The peaty clay was obtained by Prestwich from beneath 8 or
10 feet of gravel; but neither the mollusca nor the plants point to

1 Forming a botanical supplement to three papers which have appeared in
this Journal, namely :—Morris, ‘On some Sections in the Oolitic District of
Lincolnshire,’ Quart. Journ. Geol. Soc. vol. ix. (1853) p. 317 [Casewick] ;
Prestwich, ‘On a Fossiliferous Deposit in the Gravel at West Hackney,’ zbid.
vol. xi. (1855) p. 107 [Shacklewell]; Tylor, ‘On Quaternary Gravels,’ ibid.
vol. xxv. (1869) p. 83 [Grays]. :

464 PLEISTOCENE PLANTS FROM CASEWICK, ETC. [ Aug. 1897,

any great antiquity of the deposit, characteristic Pleistocene forms:
being absent :—

Ranunculus repens, L.

Rubus Ideus, L.

Rosa canina, Li.

Eupatorium cannabinum, i:

Lycopus ewropeus, L.

Alnus glutinosa, L.

Quercus Robur, L.

Grays (Essex).

The plants from Grays consist of a number of leaves, already
examined by Gaudin and Heer, and some seeds which I have been
able to wash out of the lumps of clay. The leaves, from long keep-
ing, have suffered somewhat, and perhaps to this cause is due the
absence of certain species noted in a MS. list by Heer. The missing
plants are Pteris aquilina?, Vaccinium myrtillus 2?, and Fagus ??, but
it is noticeable that Heer records all three with doubt.

Ranunculus repens, L. (seed).
Rubus fruticosus, L. (seeds).
Rosa canina, L. (prickle).
Hedera Helix, L. (leaves).
Ulmus ? (badly-preserved leaves).
Alnus glutinosa, Gartn. (leaves and cone).
Quercus Robur, L., var. sessiliflora (leaves).
Corylus Avellana?, L.
Populus, ef. canescens (leaves).
Salix sp. (leaf).
Potamogeton (seed).
Cyperus ?
Phragmites?
Grass nodes.
> Hguisetum.

The plants occur associated with, or below the remains of,
mammoth and Corbicula fluminalis. They point distinctly to a
temperate climate and mild winters, for the ivy is extremely sensi-
tive to winter cold. Both the character of the flora and the position
of the deposit suggest correlation with the temperate plant-beds of
Hoxne, which lie between the Boulder Clay and the deposit with
Arctic species. The ivy and the poplar have not previously been
recorded as British fossils.

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Vol. 53. ] IGNEOUS ROCKS IN NORTH PEMBROKESHIRE. 465

33. Some Ienzous Rocxs in NortH PremBRoKESHIRE.
By Joun Parkinson, Esq., F.G.S. (Read June 9th, 1897.)

[Puars XXXVI]

THe acid rocks which form the subject of the bulk of the
following notes are situated at the eastern end of the Prescelly
Hills in North Pembrokeshire. Although igneous rocks differing
from these do occur to a large extent, their petrological interest is
not great, and the mention made of them will be brief. The
Prescelly range has a general trend in an easterly and westerly
direction, and may be considered as extending roughly from near
the village of Rosebush—noteworthy for its slate-quarries—to the
village of Crymmych, some 7 miles to the west. The slates of the
country are coloured on the Geological Survey maps as Llandeilo ;
and it is unfortunate that the difficulty of finding fossils prevents
much further and more definite information being added.

Although apparently organisms are sometimes found in the Rose-
bush slate-quarries, neither my endeavours nor those of the men
employed in the place were successful during my visit. About
3 mile west of Crymmych, however, a few fragmentary fossils were
obtained.

One species of graptolite was found, which has been kindly
identified by Miss EH. M. R. Wood as Didymograptus comp. indentus,
var. nanus, Lapw., and some fragments of at least one species of
Trinucleus, which Dr. Woodward has kindly allowed me to submit
to him, but which were unfortunately not sufficiently well preserved
for a specific identification. Miss Wood is inclined to think that
the rocks are of Lower Llandeilo age, though there is a possibility
that they may be Lower Arenig.

This conclusion is interesting, since the masses of acid rock which
occur at the places marked Foel Trigarn and Carn Alw show all the
characteristics of a true lava-flow. Those two localities are about
13 mile apart, and although the development of the rock at either
is but small, yet there are a few points which may be of interest.

As regards the general characteristics of the rocks, slides cut
from two specimens obtained at Foel Trigarn may be taken as
examples.

The first of these, which is quarried for road-metal on the northern
side of the hill, is a compact, somewhat light blue-grey rock, often
conspicuously banded, and weathering to a deep brown. In thin
section it is seen to be cryptocrystalline, with occasional larger
grains of irregular shape and brighter polarization-tints. The slide
contains pyrite in some abundance, with a little hematite and also
flakes of opacite arranged in a manner suggestive of flow.

A variety of this rock from the southern side of the hill is porphy-
ritic, of a uniform slate-grey colour, weathers in a very slagg

Od,G.8. Ne, 212: 21

466 "MR. J. PARKINSON ON SOME [Dec. 1897,

manner, and flies under the hammer. In thin section it is micro-
crystalline, with some quantity of microfelsitic matter, and shows
an approach to a banded structure. Clearer secondary felspar is
formed in some instances, filling cracks in and forming a zone—
always very narrow—round the porphyritic crystals. :

As an instance of essentially similar rocks from Carn Alw a
specimen may be taken of a medium tint of blue-grey, with irregular
flecks and streaks of a darker colour which, on the broad surface of
the specimen, are seen to have acertain parallelism. A rock of this
character is typical of much from this locality, and may be briefly
described as being of a compact nature, rather dark in colour, breaking
with a subconchoidal fracture, not conspicuously porphyritic, and
weathering white, or occasionally to a pinkish tinge. The quartz-
crystals are corroded, and contain portions of the ‘ matrix,’ while the
felspars have undergone considerable alteration.

In some cases there is a microcrystalline, in others a confused
erystallization, which shows large irregular, though often fairly
definite, patches as the stage is rotated between the two nicols, and
with coarser areas and veins, having a tendency also in places to a
radial structure.

In many of these rocks—notably from Carn Alw—flow-structure
is beautifully developed (Pl. XXXVI, fig. 1). Ina typical specimen
the bands are very regular, about *1 inch across on an average, but
commonly exist as mere lines, the darker containing a green chloritic
mineral. In many cases this may be seen to have spread, or to be
in process of spreading, over the major part of the band, leaving often
irregular but well-defined patches, having a roughly radial crystal-
lization. There are, however, bands much thinner than the above,
possessing a crystallization normal to their length; along the middle,
and, finally, all over which the green mineral has spread. The
slide contains porphyritic felspars—monoclinic—and occasionally
a small quartz-crystal. The constituent particles of the erypto-
crystalline groundmass are generally rather elongated. Macro-
scopically there is a considerable resemblance between this rock and
those from Penrhyn. near Fishguard, recently described by Mr. Cowper
Reed.! The latter have a crystallization rather more definite and at
the same time finer, but the Carn Alw rock is more finely fiuidal.
The principal difference exists in the presence of felspar-microlites
and in the absence of the green chloritic substance from the Penrhyn
rock, both facts indicating, of course, a diversity in composition ; but
the general likeness is very great.

Possessing close affinities to the above is a light blue-grey rock,
weathering white, and traversed with some regularity by innu-
merable lighter bands and lines, which vary from about -005 to
nearly ‘1 inch in breadth. It contains porphyritic crystals of both
quartz and felspar, and in thin section the bands are found to consist
of greenish microlites and of granular ill-defined matter, apparently
essentially similar to the microfelsitic substance scattered more
sparsely through the whole of the slide. Between the bands are

1 Quart. Journ. Geol. Soc. vol. li. (1895) p 160.

Vol. 53.] IGNEOUS ROCKS IN NORTH PEMBROKESHIRE. 467

irregular spherulitic growths, the matrix in which they are set
containing an inert green ‘ chlorite’in some quantity. The arrange-
ment of this ‘chlorite’ in places strongly recalls the perlitic patch
figured by Mr. Rutley in a spherulitic rock from Beddgelert and an
epidositic felsite from the Herefordshire Beacon,’ and there can be
little doubt that much of the present structure is due to the
causes which he describes in those instances. The spherulites as a
rule are rather confusedly crystalline, and show but little approach
toa radial structure ; their outlines are usually elliptical rather than
circular, and they are free from the secondary chloritic mineral. It
is perhaps worth mentioning that the microlites forming a large part
of the bands which characterize the rock macroscopically lie in a
direction not parallel to, but at an angle with, the length of the
band, indicating—as Prof. Bonney has suggested to me—a slight
movement of the rock in a new direction, immediately prior to
consolidation, but which has not been sufficient to disturb the
parallel regularity of the bands themselves.

Consideration of this not very markedly spherulitic rock leads to
those in which the spherulites are conspicuous. In a slide from
one of these a band about 3 inch across, with spherulites 1, inch
in diameter, is cut.

The larger of these spherulites occur either singly or grouped
in twos and threes, in the latter case arranged often in a linear
manner and shading eff into axiolites. They show concentric lines
of growth, with generally a narrow outer border of clear matter in
contrast to the darker and fineiy fibrous nature of the internal
portion.

Interstitially, between the above, are closely-packed clear spheru-
lites, showing commonly concentric lines of growth rather markedly.
In the majority of cases these, like their larger representatives, have
a clear but broader edge, which is distinctly separated from the
less translucent central portion. The sharpness of the definition
between the zones suggests occasional concentric fracture and infil-
tration. These smaller spherulites are in some instances grouped
linearly, giving a scalloped appearance, on each side of a line of
granular and less definite crystallization, of some width in proportion
to the size of the spherulites, and which may extend for nearly the
entire breadth of the slide. As Prof. Bouney has pointed out,” this
kind of arrangement may be simulated in sheets of glass fused by
fire, a surface of discontinuity being formed between two layers.
In this case it would appear as if a crack had formed the necessary
starting-point.

A variety of this rock, showing minor differences in the spheru-
lites, but considerable differences in the character of the matrix in
which they are embedded, presents a few points which may be of
interest.

1 Quart. Journ. Geol. Soe. vol. xliv. (1888) p. 740 & pl. xvii.
* Pres. Addr., Quart. Journ. Geol. Soe. vol. xli. (1885) Proc. p. 91.

lo

ot

468 MR. J. PARKINSON ON SOME | Dec. 1897,

The spherulites, or rather axiolites, for they are often twice as long
as broad, show marked stages of growth even macroscopically ; indeed,
differences of texture, accentuated by an appearance of discontinuity
between the inner and more peripheral parts, suggest an interval
during their development when growth ceased (Pl. XXXVI, fig. 2).
The outer border is frequently clear, in contrast to the darker,
almost flocculent appearance of the centre; and the exterior is a
surface of easy parting, since fracture of the specimen often leaves
the knob-like surfaces of the axiolites standing out.

The matrix contains afew porphyritic crystals of both quartz and
monoclinic felspar, and a second, less numerous generation of smaller
spherulites. In thin section it is pale green in colour, slightly
dichroic, very feebly anisotropic, and easily marked with a knife.
The smaller spherulites to which I have just referred contain centrally
a greenish substance, no doubt an inclusion of the matrix in which
they lie. In places there is a slightly radial or tufted habit which
recalls chlorite, but the chemical difficulties in supposing the whole
of the matrix to be converted into such a mineral are considerable,
and I am indebted to Prof. Bonney for the suggestion that this
somewhat structureless substance is probably of the nature of a glassy
residuum, in which the iron silicates have been hydrated, and which
would answer to the palagonite of the more basic rocks.

In some instances, this hydrated glass is reduced almost to a
minimum (Pl. XXXVI, fig. 3), and the grouping of some of the
axiolites, which are similar to those just described, recalls a figure of
Zirkel’s of a specimen from Nevada.* Inthe present as in the other
case, the elongated, often sinuous, appearance of the axiolites suggests
that flow-movement was indirectly concerned in their development,
but the dark, granular, fluidal lines of the American rock, forming the
meshes in which the axiolitic growths took place, are not present here.
It seems, therefore, that the curving and at the same time complete
structure is best explained by concluding that after their formation,
but while they were still in a plastic state, a slight movement in
the unsolidified magma occurred, forcing together and bending the
axiolites, producing effects analogous to the contortion so often seen
in a flow-band, and allowing little tongues of glass to penetrate the
axiolites where such an entrance could be effected. -

It is interesting to notice that in one or two cases a fluxional
movement, which affected the particles prior to the beginning of
spherulitic growth, has left a permanent impress. This is seen in
the attempted formation of a spherulite round a porphyritic felspar ;
the bending of the flow-lines round the crystal is still distinctly
seen, while a little distance away the radial growth and zoned
structure of the spherulite are more conspicuous,

1 ‘Chemical difficulties’: these consist in the large percentage of silica and
the small percentage of magnesia which rocks of this kind contain. Assuming
such a matrix to be changed in any great degree into chlorite, it is not easy to see
what is to become of the excess of the former, or how the deficiency in the
latter constituent is to be made up.

27Micro. Petr. pel fl, pl, vi, tig. 2.

Vol. 53.] IGNEOUS ROCKS IN NORTH PEMBROKESHIRE. 469

In some cases the spherulites are not so clearly defined as those
just mentioned; they are finely cryptocrystalline, the periphery is
less regular, and the radial growth not so marked.

The separation from the magma, or from the original glass, now
represented by the inert green substance previously mentioned, has
been accompanied by the formation of lines and bands, white in the
-hand-specimen, in contrast to the blue-grey colour of the rest of the
rock, and weathering out as white ridges. There is no doubt
that these are due to fluxional action, as is shown by their parallel
habit, and the manner in which they bend round porphyritic crystals ;
also in the field the rock passes in a short distance into the ordinary
banded type. ‘The bands are now cryptocrystalline, but an attempt
at a radial growth is shown by the elongation of the particles
normally to the boundary of the band, meeting in a median line of
discontinuity which is often rather marked between crossed nicols.
Accordingly these may be regarded as an elongated variety of axio-
lite. They are closely related to other bands—in fact no hard-and-
fast line can be drawn between them—which are outlined by
markedly scalloped boundaries, and apparently formed by the linear
arrangement and mutual interference of individual spherulites.

It follows then that stages can be traced from the isolated
spherulite—outlined by the green inert substance representing the
residual hydrated glass—through stages where two or three of
these are arranged linearly, then losing the boundaries of the two
sides, passing thus into an axiolite, or into a flew-band in which
the crystallization is normal to the sides defining it in greater or
lesser degree. These structures recall the ‘granular axiolites’
mentioned by Zirkel,’ which in section show two series of roughly
wedge-shaped grains with a distinct suture running between them.
He remarks that these are closely related to the fibrous axiolites.
The suture or median line of discontinuity referred to is often due
to the dovetailing of opposed particles, but in some cases its
straightness and definiteness suggest a crack.

Passing from those rocks which show normal and complete, to
those which show incomplete spherulites, one finds, of course, the
common type in which growth has taken place from several centres
close together, so that mutual interference has prevented the perfect
form from being produced. There is, however, another and less
common variety which is characterized by the simultaneous action
of fluxional and spherulitic forces, the former having modified the
complete form which should have been produced by the latter.

As an example, a slide is selected from the same locality. The
spherulites are arranged in bands, interrupted and of irregular
thickness, parallel one to another, and much more opaque than the
rock in which they lie; but the edges of the band on either side
have been, as it were, abruptly truncated, leaving, however, a
boundary which is by no means a straight line, owing to the

1‘Micro. Petr.’ p. 174, pl. vii. fig. 1. Compare also Rutley, ‘ Felsitic
Layas of England & Wales, Mem. Geol. Surv. 1885, p. 5, pl. i. figs. 11 & 12.

470 MR. J. PARKINSON ON SOME [Dee. 1897,

incomplete nature of the fibrous growths which form the band
itself (Pl. XXXVI, fig. 4).

These spherulites occur frequently in fragments and segments,
which are often placed in such a position that they form part of an
unit whole, the missing parts being represented by confusedly
crystalline matter, and rendering the idea of an originally complete,
subsequently dispersed and broken spherulite, improbable. It is
also to be noted that, if spherulitic growth had been set up after the
final cessation of fluxion in the rock, we should have expected that
a complete, and not a partially complete, spherulite would have
formed. Suppose, for instance, that some part of a magma which
had become in a greater or lesser degree separated from its sur-
roundings be placed in conditions suitable for the formation of a
spherulite; then, fluxion being inoperative, the resulting form
would be a sphere, no matter what the shape of the differentiated
area might be, since the residual peripheral parts would not
participate in the radial growth.

This, however, as already stated, is not the case here. In other
instances the spherulites most commonly consist of fragments of
ellipses, and the banded structure characterizing the previous
rock is absent (Pl. XXXVI, fig. 5). In the less strikingly spheru-
litic parts of the slide there is decided evidence of flow-movement,
into which the radially-arranged outer zones of the spherulites pass
gradually, so that they have no definite boundary such as would
have been expected if their growth had been undisturbed.

When closely packed, these spherulites have a tendency to
mutually interfere so as to produce hexagonal bounding lines,
the interior well defined from the outer parts; in others, adjacent
members may have a common and incomplete exterior, and
there are occasional cases where axiolitic fragments are grouped
together in a manner which suggests that a curving line of
flow has been a factor in determining their present position.
There are also instances of adjacent spherulites the outer parts of
which, though fairly well formed, are connected by lines un-
doubtedly due to flow, while, in others, part of a spherulite or of a
group of spherulites may be formed of matter which has an appear-
ance strongly suggesting movement. If this had preceded
spherulitic growth and then stopped, there would seem to be no
reason why these malformations should exist; and it seems, more-
over, that any late renewal of movement which could thus modify the
symmetry would have distorted the remainder to a greater extent
than the slides exhibit. Spherulitic tufts may be seen in places
wedged in between a spherulite with which they are more or less in
continuity, and an external part which shows flow-lines and into
which they grade. Thus they appear to represent material which
was displaced outwards by fluxional movement.

MM. Fouqué & Lévy* have figured from Gratadis spherulites
disturbed by flow-movements which show some resemblance to

1 Mém. Carte géol. France, ‘ Minéral. Microgr.’ 1879, pl. xv. fig. 1.

Kol: 537] IGNEOUS ROCKS IN NORTH PEMBROKESHIRE. 471

those just described. The evidences of flow seem rather stronger
on the whole, and apparently the disturbance has taken place
entirely after the formation of the spherulites. In the case of the
Prescelly rock the structure of the slides indicates that movement
has accompanied spherulitic growth, although in places here and
there one or the other may appear to have been the stronger.

A second division of incomplete spherulites includes those in
which flow-brecciation, accompanied by but very feeble radial
growth, has resulted in the formation of globular bodies sometimes
nearly 3 inch in diameter; possessing a complete discontinuity
from, and showing a striking contrast to, the matrix in which they
he. As is common in the neighbouring rock, the specimen is
marked by lighter bands, the appearance of which is identical with
that of the nodules (if the term be allowed), so that it scarcely needs
a microscopic examination to see that the causes which have
produced the former must have been nearly concerned in the
formation of the latter also.

In hand-specimens the nodules much resemble true spherulites,
standing out prominently on a fractured surface, and leaving an oval
cavity on removal. In thin section (Pl. XXXVI, fig. 6) they are
distinguished from the matrix by their browner colour and consequent
greater opacity, while under crossed nicols they show irregular patches
of light with indefinite wavy clouds of shadow as the stage is rotated,
again in contrast to the body of the rock, which is micro- and crypto-
crystalline (often quite coarse), and which contains a green chloritic
mineral in some quantity. The ‘nodules’ are often elongated, and
are connected one to another in the manner which is usual in those
portions of a rock which have become differentiated from their
surroundings and influenced by flow-movements, since occasionally
circular, but more frequently elliptical or irregularly oval, outlines
are found, which often taper to a point. .

There is in places a somewhat indefinite suggestion of radial growth,
which in a few cases becomes more pronounced. Rather more
often there is a tendency towards a concentric banding at the edge
of the patch, giving the idea that after it had assumed its
present shape segregation was again operative. In the interior
of these ‘nodules’ there are irregular but more or less central
quartzose areas, roughly concentric with the periphery. As regards
the crigin of these masses there can be no doubt—they are —
evidently one of the results of flow-brecciation, as indeed has been
suggested in connexion with some of the Boulay Bay pyromerides.'

It seems, therefore, that a mixing of two materials, or the dif-
ferentiation of one, has occurred, resulting after brecciation in the
formation of clots which have been drawn out by the action of their
more liquid surroundings, as just described, subsequently often
losing their connexion with the original mass. The quartzose
areas are sharply defined, and roughly follow, as above mentioned,
the outline of the nodule, with occasional irregularities in various

1 Miss C, A. Raisin, ‘Nodular Felsites of the Lleyn, Quart. Journ. Geol.
Soc. vol. xlv. (1889) pp. 264, 265.

472 . MR. J. PARKINSON ON SOME [Dec. 1897,

directions. There are also fine quartz-veins, which have probably
formed the means of supply to what can be scarcely other than a

vesicle.
It must be understood that this nodular structure, if indeed it

may be called such, occurs only in one or two specimens, and it is
merely the suspicion that other and better known cases are due to
the same causes that has led me to record it here.

Before passing on to consider the true fragmental rocks, some
notice must be taken of a variety having an appearance in the field
strongly suggestive of a felstone-agglomerate.

In it white angular or subangular fragments, with a tendency to
roughly resemble an almond in shape, of an average length of 3 inch,
but which vary considerably, are embedded in a softish black
or green-black matrix, which in places contains foreign-looking
fragments, the whole presenting a well-marked type of some
constancy.

Rock with white fragments due to flow-breccration.

[The dotted portions represent the soft black matrix.]

In places the pieces of felstone are separated by a space consider-
able in proportion to their bulk; in others they are close together,
and the appearance is then suggestive of a slight cracking, followed
by a forcing apart by a second material.

It is evident that such an appearance as this might be produced
by a brecciating force after the consolidation of the rock, subsequent
infiltration giving rise to the black matrix in which the fragments
are set. But it is also clear that, if such be the right interpretation,
the magnitude of the force capable of moving neighbouring pieces
of rock apart, and often of leaving fragments of different structure
in close proximity, would have been sufficient to leave a clear
impress, at all events microscopically. Of this, however, there is no
indication, except in one instance of a brecciated felspar; if other
cases had been present they would no doubt have been visible; on
the contrary the evidence points sometimes the other way, as in

Walls 3.| IGNEOUS ROCKS IN NORTH PEMBROKESHIRE. 473

the case of a fragment of a spherulite embedded in the matrix and
having an appearance by no means suggestive of crush.

It seems then that brecciation 2m situ will scarcely account for
the facts, and one is obliged to believe that this is either a case of
a true agglomerate or a rather exceptional one of flow-brecciation.
The appearance in thin section presents some difficulties in the
way of accepting the former view, for although in some instances
the edge of the felstone-fragments is well defined, more often the
boundary is almost impossible to determine between crossed nicols.
The matrix, if such it may be called, is pale green with ordinary
light, having low polarization-tints and crowded with minute clear
spaces occupied by grains of quartz or felspar; it also contains patches
free from these grains and a lighter green in colour, as if some dif-
ferentiation had gone on in it, but the outlines are not well defined,
and the clotting appearance which it suggests is not specially
marked.

In one case there is a long porphyritic felspar which has been
bent and cracked, without displacement of the parts, in a manner
suggestive of softening and heat.

These facts, together with the absence of scoria, seem scarcely
to favour the idea of an agglomerate, while the agency of flow-
brecciation, by which a second onflow of lava has broken up and
separated a mass probably still in a plastic state, seems to account
for the observed facts. Under these circumstances one would cer-
tainly have expected to find more evidence of flow-movement; but
if, as seems likely, this ‘matrix’ represent in some measure a
hydrated glass, the changes which this would have undergone since
its solidification may have masked any traces of original fluxion.

Specimens of brecciated felstone from Pen-y-chain, for an
examination of which I am indebted to Miss Raisin, show macro-
scopically considerable resemblances to this Pembrokeshire rock
both in the characters of ‘ matrix’ and fragments. A thin section,
however, shows that the structure is not due to fluxional action.

The Fragmental Rocks

associated with those which have been just described are not
sufficiently remarkable to demand anything but a brief notice. One
of the common varieties consists of a felstone-agglomerate, the
chips having an average length of 0-3 inch and a breadth equal to
about half their length. There are also occasional fragments of
more basic rock, often in well-rounded pebbles, and identical with
those which have in places been caught up by the lavas themselves.
They are never of large size.

Scattered through the matrix are detached felspars and quartz-
fragments, with a great quantity of a greenish-grey, filmy, secondary
product, together with which occur patches of a green, dichroic, and
probably chloritic mineral, showing yellow and violet polarization-
tints, and which seems minutely fibrous or filmy. It is soft, and
can be easily grooved with a knife. In places there seems to have

474 MR. J. PARKINSON ON SOME [Dec. 1897,

been less of the finer dust and débris, and the rock is then of a lighter
colour.

Fine ashes are also found in the neighbourhood of Foel Trigarn.
These in thin sections are seen to be finely granular or crystalline.

In some cases the true fragmental nature of the rock is not easy
to make out, more especially as in places it has been considerably
crushed.

The occurrence of these pyroclastic rocks, together with the petro-
graphical evidence, leaves no doubt that the rocks which have been
described constitute part of a true lava-flow.

Associated principally with the southern slopes of the hills are
a series of rather more basic rocks, of somewhat uniform and
monotonous appearance, which will be briefly noticed here. They
occur intermittently over the entire length of the ground under _
notice, but seldom attain to any great thickness. The best exposure
is found to the right of the path leading from Rosebush village to
the disused slate-quarry at Craig-y-cwm. Here they form a rather
conspicuous cliff.

The common type is greenish grey in colour, breaking with an
uneven or subconchoidal fracture, and in general of a homogeneous
appearance, except for the presence—occasionally in some quantity—
of chloritic or quartzose amygdaloids. This even appearance may,
however, be somewhat detracted from by dark patches resulting from
flow-brecciation. ‘These are occasionally present in quantity, and,
in addition, in those cases where a crush has taken place the rocks
are difficult to distinguish in the field from true ashes.

In thin sections the rocks are seen to contain a large number of
microporphyritic felspars, both monoclinic and triclinic. The base
in which these are set contains much wmicrofelsitic matter, with
but little evidence of fluxional movement in those cases in which
flow-brecciation is absent. Opacite is often abundantly present,
and somewhat frequently the structure is obscured by secondary
products.

West of Rosebush a slightly different type is found. It is
often bluer in colour than the rocks just noticed, and contains
porphyritic felspars about ‘05 inch in length which are referable to
orthoclase. The cryptocrystalline base contains large quantities of
oligoclase-microlites. The arrangement of these, together with the
manner of formation of a considerable quantity of green, filmy,
chloritic matter, affords evidence of flow-movement.

East of Rosebush an agglomerate occurs, consisting both of these
rocks and of pieces of slate.

This fact, taken in conjunction with the general parallelism of the
outcrop of these rocks to the strike of the slates, and added to such
microscopical evidence as is afforded by their fine texture and
amygdaloidal habit, with occasional evidences of flow, leads to the
conclusion that they constitute a lava-flow antecedent to, and
slightly more basic than, that which occurs at the north-eastern
extremity of the range.

Vol. ‘53:] IGNEOUS ROCKS IN NORTH PEMBROKESHIRE. 475

In conclusion, a few words must be said concerning the diabases
or dolerites, which are by far the most conspicuous igneous rock of
the district.

They are found throughout the greater part of the length of
the hills, from Rosebush to near Crymmych. On some of the
southern slopes of the hills near the former village the outcrops of
diabase may be seen to make a high angle with the prevalent
strike of the slates, while farther north and east diabase is found
both above and below the acid lava-flow with its associated frag-
mental rocks. Hence the diabase must be considered as intrusive
and the youngest igneous rock of the district. There is also a
general linear tendency in the outcrops which suggests that part of
the intrusion at all events was of the nature of a laccolite.

As a typical example a specimen may be taken from Foel Ervr, at
the western end of the range. It is of a medium grain, of a general
greenish tinge, and shows distinct black augite-plates. In thin
section the predominating mineral is seen to be felspar, in crystals
generally long in proportion to their breadth and often somewhat
decomposed. These felspars are embedded in the plates of pale-
brown augite. The more fine-grained varieties—for example, that
from Carn Ddu-fach—resemble the above in the relations of their
augites and felspars; the latter are largely converted into grey
saussuritic products.

The coarser varieties are also essentially similar. The augites are
rather dark brown in colour, and much secondary replacement has
gone on in the felspars. ‘There is, however, a considerable quantity
of leucoxene (ilmenite), and the augites, though fairly well preserved
as a rule, show local alteration, either into a brown hornblende
giving place to a green actinolitic mineral, which itself becomes
of a lighter tint; or into a chlorite—apparently the latter may
represent a further stage of the former change. As in the other
cases, the felspars are considerably altered.

In places, as, for. example, at Carn Gyffwy, the macroscopic
appearance of the rock varies greatly in a small compass, being
either comparatively light in colour when much felspar is present,
or almost black when the predominating mineral is augite. The
development of large, irregular, white or pink felspars with no
definite crystalline shape, showing on a weathered surface simply
as white circular lumps, gives rise to a rather handsome variety.
This is found principally at Carn Meini. As in former cases,
the felspars are replaced by saussuritic products, rendering them in
places almost opaque.

In concluding these notes I wish to express my indebtedness to
Prof. Bonney for advice and invaluable help throughout; to Miss
Raisin for the loan of slides; and to Miss E. M. R. Wood and
Dr. Woodward for their kindness in examining the fossils.

PostscRIPTUM.

[After the meeting Dr. Gregory suggested to me, as a possible
explanation of the incomplete spherulites of Pl. XXXVI, fig. 4,

476 IGNEOUS ROCKS IN NORTH PEMBROKESHIRE. [ Dec. 1897,

that resorption might have produced the effects described. That
the spherulites were altered in their present position rather than
during motion after their first formation is, I think, clear from their
form and mutual arrangement. The truncated edges of the bands
do not suggest resorption, and the presence of a flow-line between
two closely adjacent spherulitic bands, and passing a space over
which resorption must have acted, necessitates after that process,
when the spherulites would appear as they do now, an amount of
movement for supposing which, as I have said, there is no
warrant.—July 1st, 1897.]

EXPLANATION OF PLATE XXXVI,

Fig. 1. Example of the finely fluidal rock from Carn Alw.

Fig. 2. Axiolitie rock from Carn Alw. The axiolites are set in a somewhat
structureless substance representing a glassy residuum. The fine
wavy lines in the groundmass are due to the effects of pressure.

Fig. 3. Another example of the axiolitic rock from the same locality.

Fig. 4. An example of incomplete spherulites from Carn Alw. The imperfect.
form which they present is attributed to flow-movement during
formation. They contain occasional minute clear spherulites giving a
fairly definite cross between the two nicols.

Fig. 5. Incomplete spherulites from the same locality, but of a different type.

For these the same explanation is put forward. The absence of
a definite boundary is seen, so that the outermost part of the
spherulite grades into the flow-lines; in the centre of the figure it is
seen that two spherulites in contact have half their outermost zone
formed, the rest being occupied by flow-lines, while between crossed
nicols traces of spherulitic structure are almost entirely lost and
replaced by indications of flow.

. 6. One of the more perfectly rounded spheroids resulting from flow-

brecciation, indications of which are still seen in part of its edge.
Locality as for preceding figures.

—_

F;

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Discussion.

The Presrpent and Prof, Bonney spoke, and the AurHor replied.

QuarT. JOURN. GEOL. Soc., Vor. LIII., PL. XXXVI.

ts

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wt eer .
9 , ™ >

IGNEOUS Rocks OF NORTH PEMBROKESHIRE.

Vol. 53] ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 477

34. Notes on a Cottecrion of Rocks and Fossits from FRanz JosEr
Lanp, made by the Jacxson-Harmsworth Exprpirion during
1894-1896. By E. T. Newron, Esq., F.RS., F.G.8., and
J.J. H. Tratt, Esq., M.A., F.R.S., V.P.G.8. (Read June 23rd,
1897.)

[Puates XXXVII-XLI.]

ConTEnTs.
Page
Md Dit Od uGhiOw, ease eae nae este meee res doe ak elated sae sy nwisiesiaicee 477
II. Previous Work on the Geology of Franz Josef Land ......... 477
MET. The Basaltsof Rranzidioset ands. oo. cscs. qectecactwaewsnace avons 482
IV. Distribution of Basalts of similar Type ..........5.....-.sceeeeeee 490
V. Fossils and Sedimentary Rocks of Franz Josef Land ......... 493
VI. The Relations of the various Fossiliferous Horizons ......... 511
elle, Conchupomiesacntcsatetseans dines nies onen Seoaepitabbassinls nad viseat dels ae 515

I. Inrropvuction.

Tue steamship Windward, which has now paid two visits to
Franz Josef Land, brought back last year (1896) a series of rocks
and fossils, collected by the Jackson-Harmsworth Expedition.
This collection, by far the most important which has reached this
country from Franz Josef Land, was forwarded to the Geological
Survey, and at the request of the Director-General, Sir Archibald
Geikie, we have undertaken its examination. Although the full
results of the geological observations recorded by Dr. Keettlitz
cannot be made known until the return of the expedition, it has
been thought desirable that a preliminary account of the district,
based on the specimens already received, should be published.

Il. Previous Work on THE GEOLOGY oF FRANZ JosEF LAND.

The geological literature relating to Franz Josef Land, though
small in amount, is sufficient to prove that those portions of the
district which have as yet been visited possess a comparatively
simple geological structure. Scattered observations have now been
made over more than two degrees of latitude by Payer, Leigh
Smith, Jackson, and Nansen, and everywhere the features observed
appear to be essentially of the same character. It is a region of
plateau-basalts comparable, not only in its main features, but also
in many of its minor details, to portions of the western coast of
Scotland. Vast flows of basaltic lava, associated in all probability
with intrusive sills of the same type of rock, form the greater
portion of the district. Sometimes the basalt descends to the level
of the sea, and sometimes, as at Cape Flora, rests on some 600 feet
of nearly horizontal strata of Jurassic age. It may be safely pre-
dicted that if the capping of snow and ice which conceals so large
a portion of the district were cleared away, the geological aspect
and pbysical features of Northbrook Island would be very similar

Fig. 1.—Sketch-Map of part of Franz Josef Land, by Frederick Gt. Jackson.
(Showing discoveries and journeys, up to 1896, of the Jackson-Harmsworth Expedition.)

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Vol. 53.] ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 479

to the northern part of the Isle of Skye, where basaltic lavas and
intrusive sills are associated with nearly horizontal strata of
Jurassic age.’

The geological observations made by the members of the Austro-
Hungarian Polar Expedition under the command of Lieuts. Payer
and Weyprecht were necessarily of a limited character. Payer
calls attention to the plateau-like aspect of the land in the
neighbourhood of Cape Tegethoff, the southern promontory of Hall
Island, and to the fact that the plateau terminates with steep
precipitous rocks.’ He refers also to the occurrence of dolerite
(the general term applied to the rocks by Prof. Tschermak) on
Koldewey and Schénau Islands, that of the latter being remarkable
for its beautiful columnar structure. He states generally that
dolerite is the prevailing rock, but refers also to the occurrence of
sandstones and of a shale containing white mica and plant-remains.
There is no means of correlating the latter rocks with the beds
discovered by Dr. Keettlitz, of the Jackson-Harmsworth Expedition.
The common occurrence of silicified wood is also noticed by Payer,
and wood of this character is abundant in the present collection.
The ship Tegethoff was abandoned, and only a few specimens
appear to have been brought back. In his general remarks on the
geology of Franz Josef Land, Payer clearly recognizes that it forms
a part of an extensive volcanic province, stretching westward
through Spitsbergen, Jan Mayen, and Iceland to Greenland.

The voyages of Mr. Leigh Smith in the Hira furnish additional
information of importance as to the geology of Franz Josef Land.
From the account of. the first voyage in 1880 given by Mr. (now
Sir) Clements R. Markham* we learn that May Island, the first
land reached, is 200 feet in height, and formed of basalt. Cape
Barents, the south-eastern promontory of Northbrook Island, is
formed of ‘ columnar basalt like the Giants’ Causeway.’ It is stated
that while the ship was in Hira Harbour Mr. Grant walked along
the shore to the eastward, presumably on Mabel Island, and after-
wards ascended with a party to the summit of the hill overhanging
the harbour (Bell Island ?), which proved to be 1040 feet above
the sea. ‘On the slope of this hill a good deal of petrified wood
was collected, and some other fossils.’ It is further stated that
‘the lowest rocks belong to the Oxford Clay, and are represented
in the collection brought home in the Mira by two belemnites.
Above the Oxford Clay the rock is of the Cretaceous period to
which the fossil coniferous wood belongs, including one very
perfect cone. There are also slabs with impressions of plants.
Over all these has been an overflow of basalt and lava, forming a
cap, as on the island of Disco.’ In the discussion which followed

1 See ‘The Tertiary Basalt-plateaux of North-western Europe,’ by Sir A.
Geikie, Quart. Journ. Geol. Soe. vol. lii. (1896) p. 331.

2 ‘New Lands within the Arctic Circle.’ See also Proc. Roy. Geogr. Soe,
vol. xix. (1874) p. 17.

3 Proc. Roy. Geogr. Soe. n. s. vol. iii. (1881) p. 129.

480 MESSRS. E. T. NEWTON AND J. J. H. TEALL ON [Dec. 1897,

the reading of the paper, Mr. Etheridge referred to the widespread
distribution of the basalts, which he regarded as being probably of
the same age as those of the Giants’ Causeway.

During the second voyage of the Mra in 1881, which unfor-
tunately terminated in the loss of the ship, a raised beach, 90 feet
above sea-level, was found in Gray Bay, and cliffs of columnar
basalt, 800 feet in height, were observed at the same locality.?
Fossil wood was found on David Island.

Dr. Nansen’s book, ‘ Farthest North,’ contains many references
to the geology of the parts of Franz Josef Land visited by him.
The first rock touched in his memorable journey towards the south
is described as a coarse-grained basalt,? and he refers to the
occurrence of basalt on the western coasts of Karl Alexander Land
and Frederick Jackson Island; also at Capes McClintock, Fisher,
and Richthofen. In justice to Mr. Jackson it should be remem-
bered that he had visited most of these localities in 1895, and had
observed the occurrence of basalt.

In many places the rock exhibited the characteristic columnar
structure in the most perfect manner. While staying with Jackson
at Cape Flora, Dr. Nansen examined the geological structure of the
neighbourhood of that cape, the points of interest being shown to him
by Dr. Keettlitz, the doctor and geologist of the English expedition.
The basalt appears at a height of 500 or 600 feet, and below this
is a soft clay containing lumps of an argillaceous sandstone, in
which fossils occur. At first Dr. Nansen held the view that the
stratified deposits belonged to a late beach-formation, but Dr.
Keettlitz showed him that these deposits actually passed under-
neath the basalt. Dr. Nansen also observed thin strata of basalt
in the clay, below the main mass. The fossils were mainly
ammonites and belemnites, and these convinced him that they
belonged to the Jurassic period. The main mass of basalt was
coarser in grain than ordinary basalt, and resembled the so-called
‘diabases ’ of Spitsbergen.

Dr. Nansen points out that the situation of the basalt on
Northbrook Island is different from that which had been observed
farther north. Here it was found at a height of 500 or 600 feet,
whereas north of lat. 81°, at Capes Fisher, McClintock, Clements
Markham, and many other localities, it descended to the sea-level.
He regards the basalt as in great part of Jurassic age.

Mr. Jackson and Dr. Keettlitz discovered innumerable fragments
of rock, containing plant-remains, resting on a mass of basalt which,
at a height of more than 700 feet above the sea, projected through
the glacier on the north of Cape Flora. Dr. Nansen was taken to
this spot by Dr. Keettlitz, and they brought away a number of
specimens, some of which were submitted to Dr. Nathorst, and

1 See the account of the voyage by C. R. Markham, Proc. Roy. Geogr. Soc.

n. s. vol, v. (1883) p. 204. ; :
2 Vol. ii. p. 8306. In his diary the rock is called a granite, but in a footnote

he adds that it was a coarse-grained basalt.

——

‘Vol.53.] © ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 481

determined by him to be of Upper Jurassic age. The fact of these
fossils having been found on the basalt also influenced Dr. Nansen
in referring this rock, in part at least, to the Jurassic period.
Kvidences of recent changes in the relative level of land and sea
are referred to in Dr. Nansen’s book. Thus, Mr. Jackson’s hut is

Fig. 2.—Elmwood, Cape Flora.

| from a photograph.—This view shows the exposure of basaits above, and the
huts of the Expedition below the talus-heaps, which are here covered by snow. |

built on an old beach +40 to 50 feet above sea-level, and other
beaches were found at still greater elevations. Raised beaches
were also observed farther north, in the neighbourhood of the hut
in which Dr. Nansen wintered.

A number of geological specimens were sent home by Mr. Jack-
son and his party when the Windward returned in 1895, and a
short note on some of these was appended by our colleague, Mr. G.
Sharman, and one of us to Mr. Montefiore Brice’s report of the
expedition." The much larger series of specimens, of both rocks and

1 Geogr. Journ. vol. vi. (1895) p. 518.
Gia. G.S:, Nov 22; K

482 MESSRS. E. T. NEWTON AND J. J. H. TEALL ON = _[ Dec. 1897,

fossils, which has now been received, throws additional light on the
geological structure of the Franz Josef Land archipelago. Although
the cliffs are so largely hidden by talus-heaps and snow, that
exposures of rock are few and far between, yet the specimens
now collected by Mr. Jackson’s party have all been so carefully
labelled and localized that it has been possible to piece them
together, so as to present what we believe to be a correct idea of
the geology of some of the southern parts of Franz Josef. Land..
We have received much help from Mr. H. Fisher, the botanist of
the expedition, who is now in England: his admirable coloured
sketches and verbal descriptions doing much to aid us in realizing
the actual conditions under which the specimens were found.
Moreover, Mr. Fisher’s patience in answering our innumerable and
perplexing queries has helped us out of many difficulties, and we
take this opportunity of tendering him our warmest thanks. We
are also under obligation to Dr. G. J. Hinde for many hints, but
especially for his Note on the radiolarian chert from the iceberg.
We have moreover received help and many kind suggestions from
our colleagues, Mr. Clement Reid, Mr. G. Sharman, and Mr. W. W.
Watts, and we desire to thank all these friends, and to acknowledge
our indebtedness to them.

III. Tue Basatts oF Franz Joser Lanp.

The basaltic rocks which form so important a feature in the
geology of Franz Josef Land are well represented in the Jackson-
Harmsworth collection by specimens from Cape Flora and Hooker
Island. All these belong to one type, although the specimens may
be massive. vesicular, or amygdaloidal ; but another and a distinct
type is represented by one or two specimens obtained from the
under-surface of an iceberg found, tilted up, in De Bruyne Sound,
between Northbrook and Hooker Islands. |

The common type will first be described. It is represented by
specimens collected in situ, and from the talus which so commonly
conceals the lower portions of the cliffs. As there is no essential
difference between the specimens collected under these different
conditions, they will be grouped together for purposes of description.
In the fresh condition the rocks are very dark, almost black, and
of medium grain. They weather in the manner characteristic of
basaltic rocks, and sometimes break up into spheroids. Examined
with a lens, the felspars are often seen to be of a yellowish colour,
and the appearance of the rock under these circumstances is such
as to suggest at first sight that olivine is an important constituent.
This, however, 1s not the case; olivine does occur occasionally,
but never in sufficient quantity to affect the macroscopic character
of the rock. ;

A special feature of almost all the rocks of the common type is
the tendency of some of the felspars to be somewhat. larger than
the others, and to occur in groups, thus producing a kind of
glomero-porphyritic structure. A few specimens may be fairly

Mole 5/3. | ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 483

termed ‘ porphyritic basalts,’ but the porphyritic structure is never
strongly marked in the hand-specimens, and is frequently not
noticeable.

Vesicular and amygdaloidal rocks are extremely common at Cape
Flora. This is a point of some interest, when considered in con-
nexion with Payer’s remark that ‘amygdaloidal varieties, so
common in Greenland, were never found in Franz Josef Land.’ !
The cavities have been filled with various substances, such as
calcite, analcime, natrolite, chacedony, quartz, and palagonite.

Under the microscope the constituents are seen to be plagioclase,
augite, magnetite, olivine, interstitial matter, and various secondary
products. The plagioclase occurs in forms giving lath-shaped
sections, and also as aggregates of somewhat larger individuals,
which mutually interfere with each other, and are more equally
developed in the different directions. A broad type of albite-
lamellation is common to both modes of occurrence, and the indi-
viduals of the larger aggregates often show, in addition, a zonal
structure and twinning on the pericline-plan. The lath-shaped
sections in a common type of rock measure about °5 mm. in leneth
by -1 mm. in breadth; whereas the individuals which compose the
larger aggregates mav measure as much as 1 or 2 mm. in their
longest diameters. There is a certain amount of variation in the
dimensions of the felspars in different specimens, but the above
figures will give an idea of the scale on which they are commonly
developed in those varieties which contain comparatively little
interstitial matter.

When the powder of the rock, freed from the fine dust by
washing, is placed in a diffusion-column of cadmium borotungstate,
the felspars form a fairly well-defined band, the centre of which |
corresponds to a specific gravity of 2°7. There is no great amount
of scattering, and a fragment of iabradorite floats in the centre of
the band. The felspar, therefore, agrees on the average with
labradorite, but the: optical characters of the zoned individuals,
and the slight scattering of the grains in the diffusion-column,
indicate deviations on both sides of the average. The central
portions of the zoned individuals are more basic than the marginal
portions, but the transition is not always continuous; so that in
the life-history of individual crystals there has occasionally been a
recurrence of the conditions which gave rise to the deposition of
more basic material. The larger individuals frequently contain
inclusions of brown glass, with or without bubbles. These inclusions
are as a rule limited to the central portions.

Augite is abundant in all the rocks, and forms, with felspar, the
greater portion of the mass in the majority of cases. Generally
only one type of augite is present. In thin sections this is pale
brown, more rarely yellowish green, sometimes almost colourless.
It is usually without any trace of crystalline form, and occurs as
grains or patches, which are often penetrated by the lath-shaped
sections of plagioclase. As a rule, several individuals having

1 “New Lands within the Arctic Circle,’ German ed. p. 267.
2K 2

484 MESSRS. E, 1, NEWION AND J.J. H. TEALL ON [ Dec. 1897,

different orientations occur in juxtaposition, so that the ophitic
structure, though present, is not so marked as it is in many of the
holocrystalline dolerites from Iceland, the Feerde Islands, and the
West of Scotland. It resembles in character and mode of occurrence
the augite of the Tynemouth and related dykes in the North of
Jingland.*

One rock-specimen, obtained from the underside of an iceberg
found, tilted up, off Eira Cottage, which otherwise belongs to the
common type, contains more or less idiomorphic phenocrysts (see
Pl. XXXVII, fig. 3) of pale greenish augite, with peripheral inclu-
sions, in addition to the ordinary augite above described. A few
grains of this mineral were isolated, and the presence of chromium
established. It is therefore, as was suspected from its appearance
under the microscope, a chrome-diopside; and the fact is of some
interest from the point of view of correlation, because Scharizer has
proved the occurrence of this mineral under similar conditions in
the basalts of Jan Mayen.” It will be shown subsequently that
the basalts of Franz Josef Land have other points of resemblance
with those of Janu Mayen.

The iron-ore occurs as grains, crystalline aggregates, and skeleton-
crystals. It is strongly magnetic, and is often present in sufficient
quantity to make the rock magnetic. ‘he felspar and augite are
as a rule remarkably free from inclusions of this mineral, which
certainly does not in these rocks belong to the earlier phases of
consolidation, as it does in so many rocks of intermediate composi-
tion. In many cases it is found only as skeleton-crystals in the
interstitial matter (Pl. XXXYVII, fig. 4), and in some the iron-
oxides have remained wholiy undifferentiated in a deep brown glass.

Olivine is by no means constantly present, and rarely occurs in
sufficient quantity to give a marked character to the rocks. It
occurs as graims, and occasionally as more or less idiomorphic
crystals. When fresh it is colourless in the thin sections; but it
is sometimes represented only by green, or more rarely by brown,
alteration-products. The occurrence of olivine in sparsely-scattered
grains or crystals seems to be a special character of this class of ©
basalts. Its absence from any particular section does not prove
that it is entirely absent from the rock, for if several sections be pre-
pared from one specimen it may be found in some and not in others.

In addition to the mineralogical constituents above described,
the rocks invariably contain a certain amount of interstitial matter,
which assumes different forms in different cases. It may occur as
a brown glass comparatively free from microlites, as palagonite
arising from the alteration of this brown glass, or as a fine-grained
matted aggregate of microlites of augite, magnetite, and felspar,
with which some colourless base may possibly be associated.
‘Transitions from the condition of brown glass to the microlitic type
may sometimes be observed, and under these circumstances the
gradual bleaching of the glass by the separation of ferriferous

1 «Petrological Notes on the North-ot-England Dykes,’ Quart. Journ. Geol.
Soe. vol. xl. (1884) p. 209. See pl. xii. fig. 6.

2 ‘Ueber Mineralien u. Gesteine von Jan Mayen,’ Jahrb. d. k.-k. gecl.
Reichsanst. vol, xxxiy. (1884) p. 707.

Vol. 53.1 ROCKS AND FOSSILS FROM FRANZ JOSEF LAND, 485

constituents is clearly shown. The amount of interstitial matter
vuries considerably in different specimens. It is very small in
amount in the massive varieties, but in some of the vesicular forms
it becomes an important constituent.

The most interesting type of interstitial matter is tte palagonitic.
Palagonite is especially abundant in the amygdaloidal varieties,
where it occurs not only wedged in between the crystalline
constituents, but also as the infilling material of some of the
amygdaloids. It is a soft black or greenish-black substance,
which ean be readily scratched with the finger-nail and cut with
a knife. ‘The powder has a soft unctuous feel when rubbed
between the fingers. Heated in a closed tube it gives off a large
amount of water. It is readily acted upon by hydrochloric acid,
and fragments leave behind a white siliceous pseudomorph. Under
the microscope, in very thin sections, it is usually seen to be of
a deep brown colour; but occasionally it contains green zones
arranged parallel with the boundarics of the space which it
occupies. In its general appearance, and in the presence of this
zonal structure, it resembles the palagonite from deep-sea deposits
described by Messrs. Murray & Renard.’ When viewed with
crossed nicols the palagonite is seen to be doubly-refracting. It
appears tu be formed of minute interlacing fibres or scales of a
brown or, more rarely, of a green colour. ‘he double refraction
of the deep-brown palagonite enables us at once to distinguish it
from the isotropic paler brown glass with which it is sometimes
associated, and out of which it has been formed by hydration.
The following analysis of this substance was made. Analyses of
palagonite and of the closely-related ‘hullite’ are quoted for com-
parison :—

i II. III. Ly. Vis
Og cx gig Se od eee ste e ee 35°48 41-26 44°73 46°76 39°44
NNO ae ce yg RNS cae 8°30 8:60 16:26 Weare 10°35
Hey). viv. etemepes ss. 12°20 25°32 14°57 1-73 20°72
CL ER SRN iE i in ee 14°60 ote ee 10-92 3°70
Mae oe. MATES eS cate sa eh 2°89 0-44 trace
SOO 653 558 2 oa Bhp. $0 1-04 9°59 1:88 11:56 4:48
5.2 CORN pines Pha Sain 710 4°84 2°23 10:37 ie:
el OP ray fake te ee eeeeetgs Beso 3°92 1-06 4°50 1:83 et
TRO scoop een cea trace ‘BA £02 0-17 oe
H,O or lossonignition ... 1680 12-79 9°56 5 13°62

99°54 100-00 10064 101-49 99°78

I. From amygdules in basalt at Cape Flora, Franz Josef Land (Teall).
1J. Palagonite from Palagonia, Sicily. The insoluble residue (1099 °/,) is
deducted and the remainder caleulated to 100. Quoted from Zirkel,
‘Lehrbuen der Petrographie,’ 2ud ed. vol. iii. (1894) p. 689.
III. Palagonite from South Pacific. Analysis by Sipéez, Challenger ‘ Report
on Deep-Sea Deposits,’ p. 307.
IV. Basic glass from the centre of the mass from which the palagonite (III) was
obtained.
V. ‘Hullite’ from Carnmoney Hill, near Belfast. Analysis by Hardman.
Quoted from Sollas & Me ffenry, ‘On a Volcanic Neck of Tertiary
Age in Co. Galway,’ Trans. Roy. Irish Acad. vol. xxx. (1896) p. 734. |

' “Report on Deep-Sea Deposits, Chall. Exp., p. 304.

485 MESSRS. E. 'T. NEWION AND J.J. H. TEALL ON [ Dec. 1897,

The published analyses of palagonite differ considerably from
each other, and the one which must now be added to the list does
not entirely agree with any one of them. It is often stated that
the iron present is wholly in the condition of ferric oxide. If this
be taken as an essential character the present substance is certainly
not palagonite, for most of the iron is in the ferrous condition.
The discovery of so large an amount of ferrous oxide was quite
unexpected, and a second determination was made with special care.
The results in both cases were identical. It may, therefore, be
taken as certain that the present substance, which so closely
resembles palagonite in its microscopic character, mode of occur-
rence, and relation to basic glass, is rich in ferrous oxide. As the
other analyses differ widely in some respects, no great harm will
be done by extending the use of the term so as to include this
substance.

The ‘hullite’ of Hardman has been shown by Profs. Cole!
and Sollas? to occur, like the palagonite of Cape Flora, as inter-
stitial matter, and as the infilling of amygdaloids. Mr. Hardman’s
analysis shows that the two substances have decided chemical
affinities. Both are remarkable on account of the large amount
of iron. Under these circumstances it became important to compare
them as regards specific gravity. Mr. Hardman gives the specific
gravity of hullite as 1-76, and Prof. Sollas uae this somewhat
extraordinary result. Five small pieces of palugonite were taken
from two amygdules occurring in a specimen collected from the
talus near Cape Flora, and placed in a solution of methylene iodide.
After twenty-four hours’ immersion it was found that two sank, one
remained suspended, and two floated in a liquid of specific gravity
2-433; four sank and one remained suspended when the specific
gravity of the lquid was lowered to 2-409. ‘The specific gravity
is therefore not constant, but it is somewhat greater than 2:4.

On comparing the analysis of the Cape Flora palagonite with that
of Palagonia it will be noted that there is a close agreement so far
as the total amount of iron is concerned, but an important difference
as regards its state of oxidation. There are further important
differences as regards the total amount of lime and the wee
proportions of lime and magnesia.

The two analyses quoted from the Challenger Report are
especially interesting. One represents the palagonitic crust, and
the other the nucleus out of which it has been formed. They
indicate, as the authors point out, that the change is accompanied
by hydration, elimination of lime and magnesia, oxidation of the
ferrous iron, and addition of alkalies.

More interesting results will be obtained if, instead of considering
the palagonite of Cape Flora in relation to more or less allied
substances from other localities, we consider it in relation to the
rock in which it occurs. This is a basalt with a specific gravity

1 <On Hullite,’ Rep. Belfast Nat. Field Club 1894~95, p. 1.
2 “Ona Voleanic Neck of Tertiary Age in Co. Galway,’ Sollas & McHenry,
Trans. Roy. Irish Acad. vol. xxx. (1896) p. 739.

Vol. 53.] ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 487

of about 2-9. The palagonite has arisen from the hydration of
the glass formed by the consolidation of the mother-liquor out
of which the other constituents, mainly labradorite and augite,
have crystallized. If we assume that the only chemical change
which has taken place is that of hydration, then the percentage
composition of the mother-liquor would be as follows :—

SU, Sa heen. buerien et doen 42°88
Ps edn tee eh a 02! 2 10:03
Be.Oy ssesscesetisstecee 1466
‘Cee eB oy itm 85 PA 765
ee Raine as EE AL oo es ha 1:26
bi IC J 6 Se it a Paes 8:38
UN OM Eee eee 2 RS. 4-74
100-00

In view of the researches of Lemberg! and the observations
of Murray & Lenard the above assumption is not warranted.
Alkalies may have been added, and lime and magnesia removed.
There is, however, no reason to believe that the reiative amounts of
alumina and iron have been appreciably changed, and we are
therefore able to draw the important conclusion that in a magma of
the type to which these basalts beiong—that is, a basic magma poor
in alkalies—progressive crystallization leads to the formation of
a mother-liquor poor in silica and alumina and rich in iron. It
is possible that the relative amounts of lime and magnesia have not
been seriously modified by the hydration, and if so we see that
crystallization may, at any rate in its earlier stages, tend to increase
the relative amount of magnesia. The partial separation of the
lime, alumina, and silica from the iron and magnesia is of course
effected by the erystallization of basic felspars, which in this class of
rocks precede the augites and sometimes even the olivine.*

This concentration of the iron, and to a certain extent magnesia,
in the mother-liquor of basic magmas does not appear to have
attracted the attention which it deserves. It shows that progressive
crystallization in these magmas sometimes leads to a result, the
opposite of that observed in the case of intermediate magmas in
which ferriferous compounds separate out during the early phases of
consolidation.” The synthetic experiments of Messrs. Fouqué &
Lévy * indicate that the formation of magnetite is not limited to one
period in the history ef the cousolidatiun of silicate-solutions, and the

' Lemberg examined the effect of water and solutions of alkaline carbonates
on volcanic glasses. He says:—-‘Fassen wir alles zusammen, so werden
basische Glaser (Palagonitglas, Tachylyt) schon durch reines Wasser hydra-
tisirt; durch Alkalicarbonate werden auch sauere Glaser sehr rasch umge-
wandelt ; dabei wird Wasser aufgenommen, Alkali gegen andere starke Basen
ausgetauscht, Kieselsaure zum Theil ausgeschieden ’ (‘Zur Kenntniss der Bildung
und Umwandlung yon Silieaten, Zeitschr. Deutsch. yevl. Gesellsch. vol. xxxv.
1883, p. 957).

2 See W. W. Watts, ‘ Guide to the Collections of Rocks and Fossils in the
Museum of Science and Art, Dublin,’ 1895, p. 78.

* ‘On some Quartz-felsites and Augite-granites from the Cheviot District,’
Geol. Mag. 1885, p. 106.

+ «Synthése des Minéraux et des Ro. hes,’ Paris, 1882.

488 MESSRS. E. T. NEWTON AND J. J. W. TEALLON [Dec. 1897,

same fact has been established by Vogt in his work on slags. The
last-mentioned author has made a special study of the conditions
under which magnetite is formed and has established the fact that
in basic slazs in some cases magnetite precedes olivine, in other cases
it’ crystallizes simultaneously with olivine, and in yet others it is
formed after olivine.

If we take the analysis quoted above, minus the water ard
alkali, as representing the composition of the mother-liquor formed
after the separation of labradorite and augite, it is clear that we
have still the material necessary to form olivine, magnetite, and
spinel (hercynite).

In view of the evidence thus furnished of the concentration of
iron, one is tempted te speculate as to the results that might follow
if the process were carried still further. Magnetite forms the matrix
of the cumberlandites of Rhode Island and 'l'aberg, in whieh olivine
and felspar occur as phenocrysts.” It is found as interstitial matter
in the ultrabasic ‘ schlieren’ in the banded gabbros of Druim an
Eidhne.? Magnetite and a green spinel (hercynite?) are intimately
associated in the pyroxenites from Scourie. Metallic iron associated
with graphite occurs as interstitial matter in certain basalts in
Greenland.’

Can it be that in some, at least, of these cases we sce the extreme
results of the process indicated above ?

We have now described the principal constituents of the common
type of basalt. The different specimens vary somewhat as to the
relative proportions of the several constituents, and still more
striking differences are due to the presence or absence of amygdaloids.
The massive varieties are of medium grain, and contain comparatively
little palagonite or other form of interstitial matter; the amygda-
loidal varieties are usually of somewhat finer grain, and contain a
considerable amount of palagonite. The mutual relations of the
constituents are illustrated in Pl. XXXVII, figs. 1, 2, 3, & 4. The
labradorite formed first, and the Jarger individuals sometimes contain
glass-inelusions in their central portions. The separation of labra-
dorite probably left the mother-liquor poorer in alumina, lime, and
soda, and this facilitated the formation of augite. The common
augite occurs in irregular grains and_ patches which are often pene-
trated by the felspars. The chrome-diopside belongs to an earlier
phase of consolidation. Magnetite has fo:med at different stages, but
it is commonly associated with the interstitial matter, and in many
specimens the felspar and augite are almost entirely free from
inclusions of this mineral. The bulk of the magnetite belongs to a

‘ Beitrage zur Kenntniss der Gesetze der Mineralbildung in Schme]zmassen,’
Avie for Math. og Naturvidensk. Kristiania.
2 See * Lithologic: al Studies,’ by M. E. Wadsworth, Mem. Mus. Comp. Zool.

Harvard, vol. xi.

3 «On the Banded Structure of some Tertiary Gabbros in the Isle of Skye,’
Geikie & Teall, Quart. Journ. Geo!. Soc. vol. 1. (1894) p. 645.

4 «On the Existence of Nickel-iron. . . in ‘le Basalt of North Greenland, ‘
K. J. V. Steenstrup, Min. Mag. vol. vi. (1886) p. 1,

Vol. 53.] ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 489

comparatively late period in the history of consolidation. Its
distribution in the rock is in accordance with the view that
progressive crystallization has tended to concentrate the iron-oxides
in the mother-liquor. In some specimens there is no recognizable
magnetite, the whole of the iron-oxide, except that which occurs
in the augite, remaining undifferentiated in the brown glass.
Microscopic sections of the amygdaloidal varieties show the connexion
between the interstitial palagonite and that which partially or wholly
fills the vesicular cavities. There is perfect continuity between the
two kinds. In cases of partial infilling the central portion of the
cavity is occupied by calcite (Pl. XX XVII, fig. 2).

Many specimens of more or less decomposed basalt from the talus
at Cape Flora contain beautiful, radiating, fibrous aggregates of
natrolite, and the same mineral occurs in a more compact form in
concentric concretions filling large, irregular cavities. It is found
also in joints in rotten basalt. Analcime occurs in detached crystals,
sometimes measuring more than 1 cm. jn diameter, and also as
ageregates of smaller crystals. The analcime of these rocks appears
to be wholly of secondary origin, and does not occur as in the
monchiquites and analcime-basalts.’

Agates are also represented in the cellection, and one large
specimen of chalcedony and quartz which was evidently formed in a
hollow cavity measures about 20 x 12x 10 ems.

Calcite is abundant in the altered varieties, and frequently forms
the infilling material of the amygdules, occurring either alone or in
association with palagonite.

The specimens of basalt on which the above description is based
were mainly collected near Cape Flora. The collection includes a
few from Hooker Island which belong to the same type, but which
are all massive.

Two or three points still remain uncertain with reference to the
basaltic formations of Franz Josef Land. Judging from analogy
with other districts of similar character, we should expect to find
both lava-flows and intrusive sills. ‘Tuffs and agglomerates are
rare in regions of plateau-basalt, but they occasionally occur as
necks and as beds interstratificd between successive lava-flows.
Then again old river-gravels a:d lake-deposits are sometimes found
between the different outpourings of basalt.” Have we evidence
of similar phenomena in Franz Josef Land? Unfortunately there
is ne petrographical character by which sills can be in all cases
distinguished from lavas in the Brito-Arctic province. The sills are
usually coarser in grain, columnar, holocrystalline, and ophitic in
structure, but none of these characters can be relied upon as distinc-
tive. lavas are often amygdaloidal, but amygdaloids are not
uncommon in sills and dykes.

' «On the Monchiquites or Analcite Group of Igneous Rocks,’ L. V. Pirsson,
Journ. Geol. Chicago, vol. iv. (1896) p. 679.

* See Sir A, Geikie’s paper on the ‘ Tertiary Basalt-plateaux of N.W. Europe,’

Quart. Journ. Geol. Soc. vol. lit. (1895) p. 331. Future observers in Franz
Jusef Land would do well to study this paper.

490 MESSRS. E. T. NEWTON AND J.J. H. TEALL ON [ Dec. 1897,

We cannot, therefore, separate the specimens into two groups,
lavas and intrusive sills. Nansen speaks.of basalt interstratified with
the underlying sediments, and the collection that we are describing
contains specimens of amygdaloidal basalt ‘ from lowest rock (6 teet
deep) having 3 feet layer of sandstone above it.’ They were col-
lected from-the watercourse running down the talus. It is a well-
known fact that the basalts of the West of Scotland are olten
intercalated between Jurassic strata,’ and this fact led the early
observers to conclude that they were of Jurassic age; but it is now
universally admitted that this intercalation is the result of intrusion
along planes of bedding, and that the basalts in question are post-
Cretaceous.

The existence of tuffs cannot be positively asserted from the
evidence before us, but there are one or two specimens of highly
altered rocks which may be tuffs. The evidence that pauses occurred
during the formation of the plateau-basalts is of a more satisfactory
character. This is furnished by a specimen of a conglomeratic rock,
mainly composed of basaltic débris aud containing rounded pebbles,
‘found in dolerite some 50 feet above lowest rock’ near Cape Flora.

We are indebted to Mr. Fisher for the following table, giving
the lowest level at which the main mass of basalt could be seen at
several localities; the base, however, was often hidden by talus :—

. feet.

Wape Moral TS ee eect ctoee 600

Cape: Gertrude, 22.25 eee 700

Cape Stephen ....2.:.<--+» seat 650

Wween Jocks. ce.) tn. ccns eet 50 at one place, 200 at
another.

Cape Grant(.2 2 eases 400 to 500

Cape’ Orowtlier 222i ee: ... 700 on one side, and sea-
level on the other.

Cape iNeale: \ 2.5.5 sk ee eee. 500

LY. Duisrrrpurion oF BasALts OF SIMILAR TyYPr.

We will now conclude this account of the ordinary basalts with |
some remarks on the general distribution of rocks of the same type.
Specimens brought home by Payer were described by Prof.
Tschermak. He says, * It [the dolerite] is a medium- grained, dark
yellowish-green, crystalline, massive rock. Plagioclase forms the
principal mass, although it only exceeds the augite by a small
amount. ‘The crystals of plagioclase are frequently 1 mm., some-
times 3 mm. long. They consist sometimes of thin and sometimes
of thick lamella. The augite is greenish grey, shows no crystalline
outlines, but forms grains which are often 1 mm. in diameter.
Inclusions of the other minerals are frequent, and also gas-pores.
Olivine forms grains which are smaller than the augite and only
seldom show crystalline faces. ‘These grains are frequently sur-
rounded with a border of a yellowish-brown mineral (eisenchlorit).
The titaniferous iron-ore cccurs in long plates or fills the space

1 Sir A. Geikie, op. cit. p. 375.

Vol.53.] | ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 491

between the other minerals.’ The resemblance of this rock to the
dolerites of Spitsbergen is pointed out, and it 1s also stated that
‘amygdaloidal varieties, so common in Greenland, were never found
in Franz Joset Land; while the rocks in the south were aphanitiv
and thus like true basalts, those in the north wers coarse-grained
and uepheline-bearing.’* From this description we may conclude
that the rocks brought home by Payer from the eastern portion of
the archipelago resemble the massive olivine-bearing varieties of
the Jackson-Harmsworth collection. Prof. Tschermak mukes no
mention of the occurrence of palagonitic matcrial as interstitial
matter, but he refers to an iron-chlorite which he regards as arising
from the alteration of olivine. It is possible that this substance
may in part represent the palagonite so common in ‘the rocks from
Cape Flora. He speaks of the‘ titaniferous iron-ore’ as ‘ sometimes
filling the space between the other minerals.’ ‘The magnetite in
the specimen that we examined contained only traces of titanic acid,
and in none of our rocks does it actually occur as interstitial matter.
Jt either crystallizes out during the later stages, or else remains
undifferentiated in the residual glass. Specimens from the northern
part of the archipelago have not as yet been examined in detail, but
both Payer and Nansen agree that mor? coarsely crystalline varieties
occur in this region. It would be interesting to know the exact
nature of the evidence on which nepheline has been stated to occur.

The more or less allied rocks of Spitsbergen have been described by
A, E. Nordenskiéld° as hyperite, and by Drasche * as diabuse. ‘They
frequently occur as sills in rocks of very variable age. Both authors
appear to regard them as contemporaneous with the strata in which
they are found, and Drasche comments on the remarkable nature of
the fact that rocks so uniform in character should be associated with
strata of all ages from pre-Carboniferous to Tertiary. The remarkable
nature of this fact disappears if we regard the rocks as intrusive
sills. |

A curious difference of opinion has arisen between Backstrom +
and Nathorst’ as to these Spitsbergen rocks. At the conclusion of
his paper on the liparites of Iceland, Backstrom calls attention to
the widespread distribution of basalts in the Arctic province which
‘extends on the one side to Spitsbergen and Franz Josef Land, on
the other to Greenland, and in the south to Scotland. Nathorst, in
commenting upon this statement, points out that basalt has not been
found in Spitsbergen, but that post-Triassic diabases occur both as
dykes and sheets (Decken). Whether the Spitsbergen rocks should
be termed basalts or diabases is a matter of comparatively shght

' * New Lands within the Arctic Circle,’ German ed. p. 267.

* «Sketch of the Geology of Spitsbergen,’ Stockholm, 1867.

° « Petrographisch-geolugische Beobachtungen an der Westkiiste Spitzbergens,’
Tscherm. Min. Mitth. 1874, p. 261.

4 «Beitrage sur Kenntniss der islandiscken Liparite,’ Geol. Foren, Stockholm
Forhandl. vol. xiii. (1891) p. 671.

° *Hiniges uber die Basalte des arktischen Gebietes,’ ibid. vol. xiv. (1892)
p. 69.

492 MESSRS. E. T. NEWTON AND J, J. H. TEALL ON _{ Dec. 1897,

importance ; it is certain, however, from Drasche’s description that
some of them are substantially identical with rocks described as
basalt from other portions of the Brito-Arctic province. I is often
not clearly recognized by Continental authors that the basalts and
dolerites of this province are more closely allied in composition and
structure to the pre-Tertiary diabases of the Continent than they
are to the Tertiary basalts of the same region. We may safely
conclude that the so-called ‘diabases’ of Spitsbergen described by
Drasche are of the same general character, and approximately of the
same age, as the basalts of Franz Josef Land.

The rocks of Jan Mayen have been described by Reusch * and
Scharizer.? The descriptions of these authors show that rocks
closely allied to those of Franz Josef Land occur en this island.
Thus Reusch speaks of the occurrence in one of the specimens
examined by him of hollow cavities ‘encompassed by a zone of
glass,’ and Scharizer records the presence of a chrome-diopside. In the
British Isles the rocks which most closely resemble the vesicular
basalts of Cape Flora are those of Carnmoney Hill, near Belfast,
and of Bunowen Tower, in County Galway.’ Both these rocks are
ophitic dolerites which contain brown glass or its hydrated
alteration-product (hullite). ‘The rocks of the Tynemouth and
related dykes * also resemble the basalts of Franz Josef Land, but
the interstitial matter which also occurs in some of the amygdules
is always devitrified.

It is evident. therefore, that the basalts of Cape Flora and Hooker
Island are similar to types widely distributed in the Brito-Arctic
volcanic province. They differ from the more common holocrystalline
ophitic dolerives in containing a small quantity of interstitial matter.
The general result of this examination is to confirm the conclusions
of Paver, Etheridge, and others that Franz Josef Land belongs
geologically to an extensive region of plateau-hasalts, including such
widely separated localities as Jan Mayen, Iecland, Green and, the
Ferode Islands, the West of Scotland and the North of Ireland.

-The second type of basalt is represented by some small angular
fragments obtained trom the underside of an iceberg in De Bruyne
Sound. It differs from the common type above described, both in
macroscopic and microscopic characters, and is, therefore, considered
by itself. The rock is dark grey in colour, compact, and of so fine
a grain that extremely thin sections and high powers are required
to reveal its true character. The specific gravity is 2°977. The
principal constituents are granules and microlites of augite (-008
mm, and :008x-04 mm.), microlites of felspar (‘004 x04), and
erystals or grains of magnetite (‘008 x-02).* It is possible that a

‘ «Det Norske Nordhavs-Expedition, 1876-1878, Christiania, 1882, p. 27.
2 «Ueber Mineralien u. Gesteine von Jan Mayen, Jahro. d.k.-k. geol. Reichs-
anst. vol. xxxiv. (1884) p. 707.

3 See papers, already quoted, by Profs. Cole and Sollas.

+ The figures are merely intended to give an idea of the scale on which the

different constituents are developed.

Vol. 53. | ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 493

small quantity of colourless interstitial matter (? analcime) may be
present. The rock contains a few scattered felspars, somewhat
larger than the microlites, and also grains of quartz and patches of
calcite. A special feature is the occurrence of aureoles of slender
augite-microlites round some of tke patches of quartz and calcite
(Pl. XX XVII, fig. 5). These microlites are larger than those of
the main mass of the rock, and show a rough tendency to a radial
arrangement with reference to the nucleus.

The occurreuce in basaltic rocks of quartz-grains surrounded by
aureoles rich in augite-microlites has been frequently described,’
and a discussion has arisen as to whether the quartz is indigenous
or exotic. In this case the aureoles surrounding quartz are pre-
cisely simiiar to those surrounding calcite.

The microscopic section also shows many groupings of augite-
microlites similar to those surrounding the grains of quartz and
calcite, but without a central nucleus. This may be, and doubtless
is in some cases, due to the fact that the section does not pass
through the centre, but the occurrences appear to be too frequent
to be entirely explained in this way. This type of basalt appears
to be rare in the volcanic province to which Franz Josef Land
belongs. We are unable to refer to any rocks from this province
with which it can be said to be closely allied.

V. Fossrts AND SEDIMENTARY Rocoxs oF Franz JoseF LAND.

The greater number of the fossils have been collected in the
immediate neighbourhood of Elmwood, the depot of the Jackson-
Harmsworth party, and around Cape Flora; but others have been
obtained farther afield, during some of the longer expeditions.
Each of the localities, with the fossils there found, will be first
noticed, aud their relations to each other afterwards considered.

The little settlement of Elmwood is on the south side of Cape
Flora, on the island of Northbrook ; it is placed on a raised beach
at an elevation of about 40 to 50 feet above the sea. Behind the
settlement are extensive talus-hcaps, above which steep cliffs rise to
a height of about 1100 feet above the sea, and this is capped by 100
fect of ice. The lower 500 or 600 feet appears to be chiefly clay,
interstratified with shales and bands of ironstone, lignite, etc.,
aud almost hidden by the talus, while the upper 500 is basalt.

1. North of Cape Flora.

The highest fossiliferous bed said to be in situ, of which the
collection has representatives, is that discovered by Dr. Keettlitz
on the north side of Cape Flora, where a bed of shale, broken
into innumerable fragments and containing impressions of plants,
was found lying across a mass of dolerite, protruding through
the west side of a glacier at a height of about 7U0 feet above the

1 «On a Group of Volcanic Rocks from the Tewan Mountains, New Mexico,

and on the Occurrence of Primary Quartz in certain Basalts,’ J. P. Iddings,
Bull. U.S. Geol. Surv. no. 66, 1890.

494 MESSRS. E. T. NEWTON AND J. J. H. TEALL ON _ [Dec. 1897,

sea. This plant-bed therefore would seem to be included in the
thickness of the basalt. A number of specimens were collected
at this point by Dr. Keettlitz and subsequently by Dr. Nansen.
The last-named gentleman submitted his collection to Dr. Nathorst,
the well-known Scandinavian authority on fossil plants, and a very
interesting account of them ‘is given in Dr. Nansen’s ‘ Farthest
North,’? together with some woodcuts of certain of the specimens.
According to Dr. Nathorst the most abundant remains were needles
and seeds of coniferous planis, which he refers to Pinus and Taxites ;
but the most interesting among his specimens are leaves of the
genus Ginkgo, only one species of which is now living, in Japan.
This genus, however, is very charactcristic of certain Oolitic deposits
in Europe. and several species have been found in the Jurassic, Creta-
ceous, and Tertiary strata of Spitsbergen, Greenland, and Eastern
Siberia. One of the forms from Franz Josef Land is believed by
Dr. Nathorst to be a new species, for which he proposes the name
of Ginkgo polaris. It is said to be a near ally of G. flabellata from
the Jurassic of Siberia, and is not unlike the G. digitata from
British Oolitic strata.

A few ferns were included in Dr. Nansen’s collection, and these
are said to represent four types, but to be too imperfect for specific
determination. One of these is referred to the genus Cladophlebis ;
two others are said to suggest the genera Vhyrsopteris and Ony-
chiopsis, While the fourth seems closely allied to the Asplenium
petruschinense described by Heer from Jurassic strata in Siberia.

PEANTS IDENTIFIED BY Dr. NaTHoRstT.

Pinus like Nordenskio’di, but probably another species.

,, species with narrow needles.

,, seeds, resembling those of Maakiana.
Taxites nearest to 7. gramineus, Heer.
Fieldenia (= Torellia) sp.

Ginkgo polaris, Nath.
eee:
Czehanowskia.
Cladophlebis.
Thyrsopteris ¢
Onychiopsis ?
Asplenium, near to A. petruschinense.

A goodly number of examples of these plant-impressions collected
by Dr. Keettlitz have been sent home, and although small and
fragmentary, as indeed were all the specimens found at. this locality,
they represent most of the forms mentioned by Dr. Nathorst.
There are many of the winged seeds of Pinus, varying in form, and
possibly representing more than one of the species alluded to in the
above list (Pl. XX XVIII, figs. 6-8). With these are numerous
pine-needles, both broad and narrow, as well as a portion of a branch
and a small cone. <A few fragments may belong to the genus
Fieldenia [Torellia] (Pl. XXXVIII, fig. 11). The peculiar form -
Ginkgo is represented by many specimens, some of which are

1 Vol. ii. p. 484.

Vol. 53.} | ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 495

referred to Dr. Nathorst’s new species, G. polaris (Pl. XXXVIII,
figs. 1-8); but there are others rather larger, with more slender
divisions to the leaves, and with seven or eight ribs on each blade,
which are very like G. siberica, Heer (figs. 4 & 5), if they are not
identical with that species.

Ferns are represented by several specimens which, although
small, are well preserved, and in some the venation of the pinnules
is particularly well shown. There is some variation in the form of
the pinnules of these specimens, but this is not greater than might
be expected in different individual plants, or perhaps even in parts
of the same frond. The only genus mentioned by Dr. Nathorst to
which these could belong is Thyrsopteris, and there is much resem-
blance between the present specimens and Th. Murrayana and
Th. Maakiana’ (P1. XXXVITI, figs. 13 & 14), which occur in the
Jurassic rocks of Eastern Siberia and of England.

The pinnules of these ferns also bear much resemblance to the
figures of Adiantites amurensis as given by Heer,” but it seems to
me best, for the present, to leave them in the genus Thyrsopteris.
In none of these forms, however, is the venation so clearly shown
as it is in some of these Franz Josef Land specimens, and in the
Jatter also the bifurcation of the veins in the pinnules seems to be
more regular and definite.

Dr. Nathorst found no cycads among his specimens; there are,
however, in our series one or two long lanceolate leaves, not quite
perfect, which so closely resemble some of those that have been
called Podozamites lanceolatus that they are provisionally referred
to that species (Pl. XX XVITI, fig. 12).

We have a few examples of long, slender, regularly-tapering
leaves (?), with few strongly-marked longitudinal ridges ; these are
broken across in such a way as to resemble a jointed stem, and
remind one of a slender Hguisetum (Pl. XX XVIII, fig. 10). The
true affinities of these specimens are not clear, but they bear some
resemblance to Baiera and Czekanowskia.

With regard to the probable geological age of these plants, we
could not do better than quote the opinion of Dr. Nathorst; but, as
we are not permitted to do so, we can only refer our readers to
‘Farthest North’ (p. 487), and say that on the whole this flora
resembles that of the Upper Jurassic beds of Spitsbergen, and
indicates a cool climate, but one much more genial than that which
obtains in Franz Josef Land at the present day.

2. East of Elmwood.

The second set of specimens to be noticed are labelled ‘ East of
Elmwood and above Sharp’s Rock.’ These are specimens of some
thin beds of shale which were found exposed zn situ just below the
basalt, but in which no fossils were found. Taken in descending
order, these are :—

1 Heer, ‘Flora Fossilis Arctica, vol. iv. Beitrage zur Juraflora Ost-Sibiriens,
ete. pl. 1.

* Ibid. pl. xxi. fig. 6.

496 MESSRS. E, [. NEWION AND J.J. H. TEALL ON [ Dec. 1897,

(i) Black shale 4 inches thick, from just below the basalt.
There is no appearance of this shale having been heated to any
extent by contact with the basalt.

(ii) Black material like the preceding, but broken into fine
particles and powder, 14 inch thick.

(111) Greenish-grey shale, 3 inches thick.

(iv) A lighter-coloured brownish clay-shale, the thickness of
which is not recorded.

3. Elmwood.

In a watercourse at the back of Elmwood the rock is uncovered
at a point about 50 feet below the basalt, and from this exposure of
‘clay sandstone’ a small, well-preserved ammonite was obtained
(Pl. XXXIX, tig. 5).

Unfortunately this ammonite is the only specimen which was
found in place at this spot, but in the same watercourse below the
exposure of rock, and apparently fallen from the rocks above, a
number of other specimens were collected, chiefly in blocks of clay-
ironstone. Among these are ammonites identical with that found in
place, as well as others which are referable to A. macrocephalus
and A. modiolaris.

The number of species found at this locality is not great, and they
will now be considered in detail.

AmMonites (Capocpras) TcHErkini?, d’Orb. (P1.XXXIX, figs. 4-6.)

To this species is referred provisionally the one ammonite (fig. 5)
found in situ 40 feet below the basalt at Elmwood, as well as several
other specimens found in the watercourse below this exposure and two
others from the side of the giacier at the western end of Cape Flora.

The ammonite found in situ is about 22 mm. in diameter, and
7 mm. thick; the umbilicus is 6 mm. in diameter. The ribs are
sharply defined and regular in thickness, having no enlargements or
tubercles ; they pass outwards from the umbilicus, and in most cases
bifureate about the middle of the side, then with a definite flexure
forwards pass over the back, which is narrow but not sharp. Most
of the other specimens above noted agree so closely with the one
just described as to need no further mention, but one of them
(fig. 4) is nearly twice the size (35 mm.) and shows that the
torward flexure of the ribs becomes less marked as the shell grows
larger. The outer part of this specimenis crushed, so that its form
is uncertain.

On comparing these ammonites with young examples of A. Tchef-
kint from Russia their agreement is found to be so close that, for
the present, they are referred to that species; but at the same
time there are small points of difference which leave some doubt.
None of the Franz Josef Land specimens are large enough to show
signs of the lateral expansion which characterizes the adult
A. Tchefkint, but the largest of them retains the same character
of the ribs on the outer whorls that it has on the inner whorls—that
is to say, the ribs merely bifurcate, and consequently those around

Vol.53-1 ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 497

the umbilicus are of the same size as those near the back. Now, in
all the larger specimens of A. Z'chefkini available for comparison,
the ribs around the umbilicus are distinctly larger than those on the
back, and only one third or perhaps one fourth as numerous. The
figures of A. T'chefkini given by De Verneuil* and Nikitin’ show
this same character.

In the Museum of Practical Geology there are several specimens
from the Kellaways Rock of Chippenham which come very near to
the Arctic ammonites, and these have been regarded as a variety of
A, Marie.

Ammonites (CaDoceRss) MopriotaRis, Luid. (Pl. XXXIX, figs. 7—
10.)

The specimens trom this locality referred to the above species are
two fragments of whorls, which show the lobes and saddles very
clearly, and in form and markings agree closely with examples of
A. modiolaris from the Kellaways Rock (figs.7 & 8). A cast
from the umbilicus of one of these fossils also agrees with this
species, and there is a similar cast from the talus of the western end
of Cape Flora which just fits the umbilicus of one of the Kellaways
Rock specimens in the Museum of Practical Geology.

One specimen from the talus near Elmwood (Pl. XXXIX,
fig. 9), embedded in ironstone and partly crushed, ‘so as to give
the appearance of a sharp back, has a much wider umbilicus than
is usual in A. modiolaris; but as this agrees with the figures given
by Prof. S. Nikitin of a specimen from Elatma,’ which is regarded
as A. modiolaris, the Cape Flora specimen is likewise referred to
this species.

Another specimen, from below where the rock was found in situ, is
more compressed, and in this respect somewhat resembles A. Hlatme’;
but, while the ribs are quite as strong as in the latter species,
there is no evidence of the large tubercles around the umbilicus.

A better-preserved example of this variety was obtained from the
side of the glacier at the west point of Cape Flora (Pl. XX XIX,
fig. 10).

AmMonitEs (MacrocEPHALITES )MACROCEPHALUS,Schloth. (Pl. XXXIX,
figs. 1-3.)

The specimens from the present locality referred to this species
are not good, but a much better example is that received in
the earlier consignment and noted by Mr. G. Sharman in the
Geographical Journal,’ a further examination of which has convinced
us that it is the true A. macrocephalus (fig. 1). In these specimens
the ribs pass directly outward from the small umbilicus, and, after

1 « Géologie de la Russie d’ Europe,’ vol. ii. (1845) pl. xxxv.

2 Mém. Acad. Imp. Sci. St. Pétersb. ser. 7, vol. xxviii. (1881) no. 5, pl. iii.
3 Nouv. Mém. Soc. Imp. Nat. Moscou, vol. xv. (1885) pl. xi. fig. 48.

4 Nikitin, op. cit. vol. xiv. (1881) pl. xi. fig. 21.

> Vol. vi. (1895) p. 518. ;

O73.G6.8. No. 212.

bk)
oa

498 MESSHS, BE. T. NEWION AND J. J. H. TEALL ON [ Dec. 1897,

bifurcating, run over the back without any forward flexure; they
agree with British and Continental examples of this species, and
attention may be especially directed to Prof. Nikitin’s’ figures of
specimens from Kellaways beds near Elatma, in Central Russia.
Another specimen found upon the talus-heap, which includes
about half the shell, has rather more rounded whorls; but, as it
resembles some of the inflated forms which have been referred to
A, macrocephalus, it is provisionally allowed to remain here

(Pl. XXXIX, fig. 3).

Betemyites Panperti, d’Orb. (Pl. XXXIX, figs. 11-14.)

Fragments of several belemnites have been collected at No. 3
locality, but only a few of them can be determined with any cer-
tainty ; on comparing them, however, with better fragments from
the talus, there is no doubt as to their being the same species.
These belemnites belong to the group in which the radiation, seen
on the cross-section of the guard, is excentric, as in the well-known
B. lateralis. In the specimen now under consideration the guard
is not flattened dorso-ventrally, as in the Jast-named species, but to
a slight extent laterally, and there is a distinct though not very deep
ventral groove near the apex, and extending a short distance along the
guard. The most perfect specimen (Pl. XX XIX, fig. 11) was found
on the talus at the western end of Cape Flora: it is only about
2 inches long, and shows nothing of the alveolar cavity. Other
examples retaining this cavity show that it is excentric (fig. 12).

A comparison of these belemnites with a series from Russia, in
the possession of Mr. Lamplugh and named by Prof. Alexis Pavlow,
left no doubt as to their agreement with examples of B. Panderi, a
species which has been recorded from the Middle Kellaways and
passes upward to the Kimeridge Clay.”

PrEcTEN cf, DEMISSUS.

The mould of a small Pecten evidently indicates a shell closely
allied to, if not identical with, the common Oolitic Pecten demissus,
which is one of the species recognized in the Upper Jurassic rocks
of Spitsbergen.

Goreonta (?). (Pl. XXXIX, fig. 15.)

On one of the ironstone-blocks is to be seen a long cylindrical
body, about 1 mm. in diameter and 70 mm. long, the nature of
which is by no means clear. Only part of this now remains, and
it seems to be entirely replaced by iron pyrites. Externally it is
almost smooth, with a few transverse, very fine lines. This fossil
calls to mind the rod of the living Pennatula and that of the
Graphularia from the London Clay; but it is not now a continuous
rod: there are regular intervals here and there, reminding one of
the interrupted condition of the stem in the genus Jsis and its

1 Nouv. Mém. Soc. Imp. Nat. Moscou, vol. xv. (1885) pl. viii. fig. 44.
2 §. Nikitin, ‘ Ueber die Beziehungen zwischen der russischen u. der west-
europaischen Juraformation,’ Neues Jahrb. vol. ii. (1886) p. 205.

Wol:e53. | ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 499

allies. These intervals may, however, be due to breakage before
being embedded in the rock.

PuHospHatic NopuLEs. (Pl. XX XVII, fig. 6.)

Rounded and ovoid nodules of a pale brown colour externally, but
black or dark brown internally, occur with these fossils, and ap-
parently at almost all the horizons from which fossils have been
collected; mostly they seem to have been free in the clay, but
sometimes they are included in the clay-ironstone. These nodules
vary much in size, some being less than an inch in diameter, others
3 or 4 inches in length and perhaps 2 inches in diameter. Thin
sections under the microscope show for the most part a mass of fine
débris with nothing definable; but some specimens show in parts
small masses of minute oval bodies, with a long diameter of 1 mm.,
which agree in form and size with the small coprolites described
by Mr. A. Strahan’! from the Phosphatic Chalk of Taplow, and
indeed there can be little doubt that they are the droppings of some
small animal. And further, upon closer examination with the
microscope, these minute ovoid bodies may be seen pressed closer
and closer together, until at last they form one mass; but in most
cases the separate pellets may be still distinguished. A number of
these nodules have been tested, and in all cases they proved to be
rich in tricalcic phosphate.

The following forms have been identified from this horizon at
locality No. 3 :—
Ammonites (Macrocephalites) macrocephalus.
is (Cadoceras) Tchefkini ?
5 a, modiolaris.

a var.

Belemnites Panderi.
Pecten cf. demissus.
Gorgonia @

Phosphatic nodules.

Precisely similar forms have been found in the talus at other
points near Elmwood, and on the side of a glacier-slope at the
western point of Cape Flora.

This series of fossils, although small, is of the greatest interest,
inasmuch as it contains ammonites which give no uncertain indica-
tion of the horizon to which they must be referred. Ammonites
modiolaris is distinctly a Kellaways Rock form, although extending
into the true Oxford Clay. The occurrence with this of A. macro-
cephalus, which not only occurs in the lowest Oxford Clay and
Kellaways Rock, but is perhaps the most characteristic ammonite of
the Cornbrash, shows very clearly that beds of lowest Oxfordian
age occur at Cape Flora at a height of about 400 or 500 feet above
the sea, and doubtless correspond to some extent with the ‘ macro-
cephalus-beds’ which are now known to have so vast an extent
throughout the northern hemisphere, if, indeed, they do not also
occur in Australia (see references on p. 515).

* Quart. Journ. Geol. Soc. vol. xlvii. (1891) p. 356.
2L 2

500 | MESSRS. E. T, NEWTON AND J.J. H. TEALL ON ‘[ Dec. 1897,

4, Windy Gully.

The next exposure of rock to be noticed is that which was
found at the southern end of Windy Gully, a valley north-east of
Elmwood, running nearly north and south. Near the southern
end of this valley there is a projecting shoulder of rock, and on
this, at a height above the sea of about 300 feet,’ a number
of fossils were obtained, nearly all of them being in hard
concretions or in phosphatic nodules. Dr. Keettlitz is satisfied that
they were in situ; but even if not actually in place, they could
only have been weathered out of the rock on which they rested.

These beds seem to be lower in the series than those of No. 3,
unless the strata are less horizontal than we understand them to
be, and they have yielded a different set of fossils ; the most striking
ot these are some ammonites which are believed to be varieties of
A. Ishme, a species described by Keyserling from Ishma in Petchora

Land.

Ammonites (MacrocerHatites) Isumm, Keys., var. ARCTICUS.
(Ply XG.)

Several examples of this ammonite were found, but they vary
somewhat in form. The most typical specimen is also the most
perfect (Pl. XL, fig. 1); it is about 22 inches in diameter, and
its greatest thickness measures 13 inch. The ribs, which are
sharply defined, pass outwards, with a distinct inclination forwards.
At a distance from the umbilicus of about one-third the height of
the whorl, the ribs bifurcate, and then pass over the back. Occa-
sionally there is a single rib interposed. The umbilicus is very
small, less indeed than is usually the case in A. macrocephalus,
although it is equally small in some specimens that have been
referred to the latter species. In nearly all the above points our
specimen resembles A. macrocephalus, but on closer examination
it is found that the whorls do not increase so rapidly, and as at
the same time they are more involute, the outer whorls are much
more encroached upon by the whorl which precedes it; so that
while in A. macrocephalus the last whorl is encroached upon for
less than half its height, in the present form the encroachment is
always more than half the height, thus indicating a different mode
of growth. And further, the sides of this species are less inflated
around the umbilicus, and more so towards the back, so that the
cntire shell has a different aspect.

If this specimen be compared with Keyserling’s figure of
A. Ishme from Petchora Land,’ it will be seen that in most of
those points in which our specimen differs from A. macrocephalus it
approaches A. /shme; but at the same time the inner whorl of
Ishme does not encroach so much upon the outer one as is the
case in the Arctic specimen. This encroachment of the whorls,
involving, as it does, a different growth of the shell, may perhaps be
thought sufficient for the establishment of a new species, and if so

1 (Dr. Keettlitz says ‘ over 400 feet.’ ]
2 «Reise in das Petschora-Land,’ 1846, p, 381, pl. xx. figs. 8 & 9.

Vol. 53.] ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 501

the name of A. arcticus may be used ; but it has seemed better for
the present to include this form in the species A. Jshme, and call
it a variety—arcticus.

Among the ammonites collected from this locality there are two
others which agree with the one described, but are less perfect ;
besides these are two which, agreeing with the type in all main
particulars, differ in being more inflated, and one of them has
coarser ribs (Pl. XL, fig. 2). Still another specimen, showing all
the characters of the type, has the outer whorl nearly smooth,
although it is a rather smaller shell (Pl. XL, fig. 3). The specimen
above described (fig. 1), however, shows the beginning of this
smooth outer whorl, but it must have been a considerably larger
individual.

BELEMNITES Sp.

A number of portions of belemnites were found at this locality,
but none of them are perfect enough for specific determination.
Two of these are phragmocones of some large species, contained in
nodules. Another specimen gives evidence of a long slender form,
apparently circular in section and concentrically radiated. This
belemnite is preserved in a block of ironstone, and possibly belongs
to another bed.

The remainder of the specimens are much decomposed: some of
them seem to have been compressed laterally and to show a deep
ventral groove. One specimen is a short form, with the alveolar |
cavity seemingly reaching to near the apex.

Although it is tolerably clear that these Belemnites represent at
least three species, yet there is no evidence of an excentric form
which could be referred to B. Panderi.

Phosphatic nodules occur. (See remarks on p. 499.)

List of Fossils from Windy Gully.

Ammonites (Macrocephalites) Ishine, var. arcticus.

Ke a: » inflated variety.
45 a », smooth variety.
Belemnites, 3 species.
Phosphatic nodules.

Although it is clear, from their relative height above the sea, that
these fossils occupy a lower horizon than the bed with A. macro-
cephalus and A. modiolaris, yet the fossils themselves give no
evidence that such is the case, and it is quite possible that they may
belong to the Lower Oxfordian. It seems likely, however, that
being 150, or perhaps 250 feet, lower in the series of beds, and
the fossils of a different type, they represent a somewhat lower
horizon and may perhaps be more nearly of the age of the Corn-
brash.

5. West of Elmwood.

Ata spot about 500 yards west of Elmwood, and some 30 or 40 feet
above the sea, ‘ sandy shale’ was found zn situ, and from this were

502 MESSRS. E. T. NEWTON AND J.J. H.TEALL ON [| Dec. 1897,

collected a number of fragmentary fossils which had been washed out
from the rock. These fossils are mostly either pieces of belemnites
or parts of a large species of Avicula, but there is one fragment of an
ammonite allied to A. Gowerianus, which is as yet undetermined.

BELEMNITES sp.

Most of the fragments of belemnites from this locality are so
much broken and decomposed that it is hopeless to think of specific
determination, nevertheless there are a few points which may be
noticed. There are evidently two if not three forms, but none of
them can be referred to B. Pandert, as they do not show the
marked excentric radiation of the transverse section characteristic
of that species. One form is compressed, with a well-marked
groove near the apex and a slightly excentric radiation.

A second form is similar, but much more compressed, and there
seems to have been a deep groove extending from the apex some
distance up the guard.

The third form is cylindrical, concentrically radiated, and with a
comparatively acute apex.

Some of these belemnites may be the same as those from
locality 4.

AvicuLa sp. cf. Inzeuivatvis. (Pl. XL, fig. 4.)

There are several of these large aviculas, but all are more or less
crushed and broken; some of them, probably on account of break-
age, look more equilateral than others, and at first sight remind
one of Pecten; but the large wing on one side shows that they do
not belong to that genus.

The best-preserved specimen (fig. 4) in its present condition is
12 inch in length; but, with the exception of the umbo and a
piece of the hinge, all the margins are broken away, and, judging
from other fragments, the species must have reached 3 or 4
inches in diameter. One valve is moderately convex, while the
opposite valve is concave. Strong ribs radiate from the umbo to
the margin; between these are finer ribs, and a third still smaller
series are to be seen between each of these, giving the shell much
the appearance of a well-marked A. inequivalvis, but in that species
the ribs are not nearly so strong. The concave valve is less
distinctly marked than the other. The hinge is long, and the
posterior wing is much larger than the anterior. Some of the
specimens appear to be more equilateral than others, but this is
believed to be due to crushing, and as all have similar markings
they are regarded as one species.

The small height above the sea at which this exposure of rock is
situated, to the west of Elmwood, shows that it occupies a position at
about 250 feet below the bed with Ammonites Ishme var. arcticus
at Windy Gully, but the specimens give no idea of their age.

Vols. | ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 503

6. Cape Gertrude.

Cape Gertrude, which is some 2 or 3 miles east of Cape Flora,
rises to a height of about 1100 feet above the sea. Mr. Fisher,
who has carefully examined this locality, says that the uppermost
100 feet is basalt, columnar above, but more irregular underneath.
From the base of this basalt to the sea-level the face of the cliff is
almost wholly hidden by talus ; but at one place the débris has been
cleared away, apparently by ice or rock falling from above, exposing
a series of sedimentary beds more than 200 feet high by about
100 feet wide, the highest part being between 300 and 400 feet
above the sea. Dr. Keettlitz, with Mr. Fisher, measured the section
thus exposed, and they found as many as seventy beds of sand,
flaggy sandstone, pebbly sand, shales, lignite, etc., varying in
thickness from 3 inches to 25 feet. The extraordinary number of
thin beds of diverse character shown in this section points to
rapidly-varying conditions of deposition, and possibly to oscil-
lations of level; while the beds of lignite indicate, to some extent
at least, a freshwater origin.

With the exception of this lignite, and some wood found embedded
in the lower part of the basalt, no fossils have been obtained from
this section, and consequently the beds cannot be correlated with
those at Cape Flora. The lignite-seams at the latter locality, and
the few indications there seen of the nature of the beds, appear to
indicate many rapid alternations of thin beds, similar to these
at Cape Gertrude; and, judging from this and the height of the
beds above the sea, it is likely that the Cape Gertrude section
corresponds to part of the Jurassic series present at Cape Flora.

Much interest attaches to the discovery above mentioned of the
masses of wood in the lower part of the basalt ; for Mr. Fisher says
that it is of precisely the same character as the silicified wood which
has been found so abundantly on the talus at Cape Flora and also at
Cape Gertrude; but this is the one place where it has been found
im situ, and is the only clue that we at present possess as to its
place of origin.

7. Cape Stephen.

We have now to travel some 20 miles west of Cape Flora to
Cape Stephen. At this point, and also between here and Cape
Grant, a hard calcareous sandstone was met with, near the sea-
level and under the raised beach. This bed, which is in situ,
contains an abundance of carbonized plant-remains, but they are
not well preserved, and in none of them can the details of structure
be seen. Consequently their determination cannot be settled with
that degree of certainty which could be wished. Although the
stems of Hquisetaceze and some other forms are not unlike species
with which we are familiar in the Yorkshire Lower Oolites, yet
these Arctic specimens seem to agree best with the flora described
by Prof. Schmalhausen from Petchora and Tunguska.’

1 Mém. Acad. Imp. St. Pétersb. ser. 7, vol. xxvii. (1880) No. 4.

504 MESSRS. EB, T. NEWTON AND J. J. H. TEALL ON ‘[ Dec. 1897,

Puyiiotarca (Eeutsrerires) ¢f. cotumnaRis, Phil. (Pl. XLI, figs.
1-3.) .

Several striated and jointed stems, such as we have long known
under the name of Eguisetum columnare in the Yorkshire beds,
occur in these sandy deposits at Cape Stephen. These stems vary
from 7 to perhaps 14 inch in diameter. In two instances, what
looks like an outer sheath of a joint is preserved, showing at one end
the oval spaces to which the whorl of spikelets or perhaps branches
was attached. There is also one portion of a ‘disc’ with the
spikelets still attached.

Rarprozamitss ? cf. Gaprerti, Schmalh. (Pl. XLI, figs. 6 & 7.)

The cycadaceous leaves of various shapes and sizes from Northern
Siberia which are referred by Prof. Schmalhausen to the above
genus and species seem to find their counterparts among the plant-
remains on these slabs from Cape Stephen. Some of these leaves are
slender and lanceolate, others broader and more oval, but each leaf,
as far as can be seen, has fine ribs running nearly parallel from
end to end. A portion of what may be a large oval woody leaf of
this form, in its present broken condition, measures nearly 2 inches
in width.

Anomozamites? (Pl. XUI, fig. 8.)

A fragment of what appears to have been a large leaf of a Cycad
allied to Anomozamites shows what seems to be a broad midrib and
on one side three unequally divided portions of the leaf, thus
resembling the genus Anomozamites ; it is introduced here for the
sake of calling attention to the possible presence of this genus, but
the specimen is not sufficient for certain identification.

ZAMIOPTERIS ? cf. GLOSSOPTEROIDES, Schmalh. (Pl. XLI, figs. 4& 5.)

There are a number of more or less fragmentary leaves to be seen
ou these slabs, which, while varying in size, agree in being broadly
lanceolate and in having a venation which passes obliquely outwards
from the middle line forward to the periphery, but without a
definite midrib. The venation of these leaves certainly appears
coarser than those shown in the figures given by Schmalhausen, but
as it is possible that this may be due to their bad state of preservation,
I have provisionally referred them to Zamiopteris,'

ASPLENIUM cf. WHITBIENSE, Brongn. (PI. XLI, fig. 9.)

A portion of the frond of a fern with pinnule short and pointed,
with entire margins and with a base attached by its whole width, is
believed to represent this species, which, besides its original home,
the Yorkshire Oolites, is said to occur in the north of Siberia. The
venation of the Franz Josef Land specimen is entirely obliterated,
and consequently the determination can be regarded as only doubt-
fully correct.

1 [Compare also with Gangamopteris. See Seward, Quart. Journ. Geol. Soc.
vol. liii. (1897) p. 324. ]

- fe
ee

es

Vol. 53.] ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 505

List of Fossils from Cape Stephen.
Phyllotheca cf. columnaris, Phil.
Rhiptozamites? cf. Gapperti.
Anomozamites ?

Zamiopteris cf. glossopterotdes.
Asplenium cf. whithiense.
Bituminous shale.

The striking resemblance between this series of plant-remains
from near Cape Stephen, and those described and figured by Prof.
Schmalhausen from Lower Tunguska, can only lead to the inference
that they are approximately of the same age. This Tunguska flora
was at one time supposed to be Palwozoic, but Prof. Schmalhausen
afterwards regarded it as of Oolitic age, and even referred it to
the Great Oolite.*

There is no stratigraphical evidence available which might indicate
the position of these plant-beds at Cape Stephen, and the distance
between them and Cape Flora prevents any correlation with the
strata there exposed, as we know nothing of the possibilities of
change of dip or faulting which may occur in the 20 miles which
intervene. At the same time it may be remembered that the
probable north-easterly dip of the beds in Franz Josef Land would,
if correct, bring these beds some little distance below horizon No. 5
al Cape Flora, where indeed beds of Lower Oolite age might be
expected to occur.

Bituminous paper-shales occur in close relation with these
sandstone plant-beds, at the locality between Cape Stephen and
Cape Grant sometimes called ‘Tween Rocks,’ but it is not known
whether they are merely in restricted patches or occur as regular
beds. This shale contains a large amount of combustible matter,
and burps with a good flame.

Near the spot at Tween Rocks where the plant-bed was found,
a bed of coaly lignite was discovered at a height of about 100 feet ”
above the sea; this, Mr. Fisher tells us, was undoubtedly in situ.
A stream of water had cut a channel for itself in the almost perpen-
dicular cliff and had exposed this stratum, a good-sized block of which
has been sent home, but is now split into many pieces, a consequence,
probably, of its having been frozen. This coal burns with a good flame,
and was recognized by the discoverers as a possible supply of fuel ;
it is not merely a lignitized tree-stem, but is composed of crushed
and compacted vegetable matter. One point of interest about this
coal is that in parts macrospores can be seen with a lens, reminding

1 (Mr. Seward, in the August number of this Journal (vol. liti. 1897, p. 325),
says that the rocks described by Schmalhausen are probably of Permian age
(see Zeiller, Bull. Soe. géol. France, ser. 3, vol. xxiv. 1896, p. 466). IPf this be so,
then the series of plant-remains from Cape Stephen, which are so similar to
those from the Tunguska deposits, may prove to be of the same age. But
an Oolitic facies in the case of Permo-Carboniferous plants is so remarkable
that, in the absence of some characteristic form, such as the Stgillaria described
by Mr. Seward from the South African beds, it would hardly be safe to regard
these Cape Stephen plant-beds as of Permian age. |

2 Dr. Keettlitz says that this bed is 300 feet above the sea.

506 MESSRS. E. T. NEWTON AND J.J. H. TEALL ON [ Dec. 1807,

one of the ‘ spore coal’ so commonly met with in ‘Coal Measure’
coal; and: on examination with the microscope this portion of the
lignite was found to be largely made up of micro- and macrospores.

This coal-seam, so far as we can judge, occurs about 100 feet
above the sandstone which has yielded the plant-remains, and
it may be that it belongs to beds of about the same period. A
similar lignite or coal was found on the moraine at Cape Richthofen,
but it is not certain that it contains macrospores.

There is still a specimen from Cape Stephen which has to be
noticed; but, as it was obtained from the talus at 300 feet above the
sea, it is evident that it must have been derived from a bed situated
at that or some greater elevation. The specimen is a slab about
10 inches square and 13 inch thick, wholly composed of layers
of plant-remains completely silicified ; it is black throughout, but
one surface is weathered white. ‘The greater part of the plants are
strap-like leaves from 4 to 9 mm. wide, and the longest piece
measures about 110 mm., but none are perfect at the ends; the
broadest leaf has 11 longitudinal ridges. They remind one of Bazera
and Podozamites, but there is no evidence of their mode of attach-
ment, and their true affinities are uncertain.

On this slab there is a fan-like leaf which is believed to be an
undivided Ginkgo-leaf, like that of G. imtegriuscula from Jurassic
beds in Spitsbergen,’ but it has a still closer resemblance to
G. reniformis, Heer, from Tertiary beds on the Lena.? As the
identity of this Ginkgo is not established, it can only be taken as
an indication of the possibility of the specimen being of Tertiary
age, and the other plants on the slab do not seem to militate
against this; the piece of a conifer-branch close to the Ginkgo
might be of almost any age. It is quite possible, on the other
hand, that this slab has been derived from a bed representing at
Cape Stephen the Upper Jurassic plant-bed of Cape Flora. Finally,
it may be that this silicified slab is of the same age as the silicified
wood which is so abundant in Franz Josef Land; but the age of the
wood has yet to be settled. )

8. Cape Crowther.

Cape Crowther, which is some 12 miles north-west of Cape
Grant, has been visited, but the only specimens that we have
received from that locality are a piece of the ubiquitous silicified
wood, a mass of silicified plant-remains, and some black-banded
chert containing vegetable tissue. These fossils were not found in
place, but were picked up from the highest raised beach.

9. Cape Neale.

About 6 miles still farther north-west is Cape Neale, the most
westerly point from which we have received specimens. On the

1 Heer, ‘Flora Fossilis Arctica,’ vol. iv. (1877) pt. i. p. 44 & pl. x. figs. 7-9.
2 Ibid. vol. y. (1878) pt. ii. p. 82 & pl. viii. figs. 24-25.

Wol53-| ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 507

summit of this headland, which reaches a height of 700 feet,
there is a level plateau free from snow, and from here we have
received some silicified wood which is stated to be part of a large
block found protruding from the soil. With this wood were some
black flinty specimens containing plant-remains, and likewise frag-
ments of what looks like siliceous sinter. The upper 250 feet of
Cape Neale is formed by basalt, and it was on this that the fossil
wood was found.

10. Hooker Island.

Hooker Island, which lies about 20 miles north-east of North-
brook, has been visited by Mr. Jackson with some of his party,
and on the higher raised beach, as Mr. Fisher tells us, several
small flints and cherty specimens were obtained from the ‘ soil,’
which soil is formed of disintegrated basalt. The fiints and cherty
specimens all seem to contain traces of vegetable tissue, but this is
very indistinct.

11. Cape Richthofen.

During Mr. Jackson’s journey to the north a number of speci-
mens were collected and labelled 80° 51' N. and 53° 40' E., which,
according to the map, seems to be at or near Cape Richthofen
The specimens were found on the top of a lateral moraine which is
said to be 300 feet high and 500 yards wide, but the height above
the seais not stated. The specimens are fragments of basalt, rotten
vesicular basalt, brown sandstone, cherty nodules, lignite, friable
sandy shale with plant-remains, and a small mass of compressed
vegetable remains. About some of these a few words may be said,
but it is unfortunate that they were not an sztu.

One of the nodules (No. 345) is a grey-and-whiie cherty flint,
which under the microscope is seen to be chalcedonic and contains
some indistinct foraminifera which remind one of Rotalia, but they
are not sufficient for determination and give no clue as to age. The
latter remark may be also applied to the large sponge-spicules seen
in a second cherty nodule, which look like one of the ‘ glass-rope’
sponges.

Two of the pieces of lignite are really pieces of tree-stems or
branches retaining the outward form, put they are so much altered
and in so friable a condition that their microscopic structure has
largely been obliterated. It is not quite certain what the wood
is, but an appearance which may represent spiral fibres and single
rows of discs points to the possibility of its being allied to the yew-
tree.

Some of the lignite seems to be composed of fragmentary vegetable
matter, and is not unlike that from near Cape Stephen, which
contains the macro- and microspores.

There are several pieces of a sandy shale which is exceedingly
friable and almost black with carbonized vegetable remains; but
these are so altered that at present nothing distinct has been made
out, and the nature of the plants is uncertain.

The compressed mass of plant-remains is very recent-looking ;

508 MESSRS, E. T. NEWTON AND J.J. 6. TEALL ON [ Dec. 1897,

it is mixed with a little muddy matrix, and readily breaks up on
soaking in water; when this is done the mass separates into small
pieces, perhaps % inch wide and, say, 1 inch or less in length, flat,
and as thin as paper. With these are other fragments, broader,
but, like the first, so much altered that nothing can be made out
of them. Mr. Clement Reid, who is so familiar with Pleistocene
plants, has seen these, and feels sure that they are not so recent
as Pleistocene, but thinks that they are probably of Tertiary age.

Raised Beaches.

The occurrence of raised beaches in many places in Franz Josef
Land is well established. One was noticed by Mr. Leigh Smith at
Gray Bay, west of Cape Grant, 90 feet above sea-level. Mr. Jackson’s
hut at Elmwood is on an old sea-beach 40 to 50 feet above the sea,
while there are others at higher and lower levels. The bones of
a whale (probably Balena mysticetus) are mentioned as being found
near Mr. Jackson’s hut. Similar raised beaches occur on Frederick
Jackson Island, showing that the movement of upheaval is not
confined to the southern parts of Franz Josef Land, where most
observations have been made. At the northern end of Ginther’s Bay
raised beaches were observed by Dr. Keettlitz, and from the lower
one pebbles of basalt and specimens of Saacava arctica were
collected ; similar beaches were also seen by the Jackson-Harmsworth
party at Cape Crowther, at Cape Stephen, at Hooker Island, and at
Windy Gully; from the latter, Trophon antiquus, Tr. gracilis,
Mya arenaria, and Balanus concavus were obtained.

Silicified Wood.

The common occurrence of silicified wood has been noticed by
all who have visited Franz Josef Land. Lieut. Payer alludes
to it; Mr. Leigh Smith and Mr. Grant collected specimens; the
first consignment of fossils from the Jackson-Harmsworth expedi-
tion contained some fine specimens; Dr. Nansen also notices it;
and the present series of specimens from the Jackson-Harmsworth
party includes many examples, some of which are large and formed
part of a tree-stem.

This silicified wood is widely distributed in the Franz Josef
archipelago, for Lieut. Payer’s specimens must have been from the
eastern islands, while we have evidence of it from Capes Flora,
Crowther, Neale, andGertrude. Mr. Leigh Smith’s specimens seem
to have been found on Mabel Island. In nearly every case this
wood has been found on the talus-heaps, and the only place where
it has been found zn situ is at Cape Gertrude, where Dr. Keettlitz
and Mr. Child discovered a mass of it embedded in the lower part
of the basalt at a height of more than 700 feet above the sea. On
the plateau at the summit of Cape Neale, which is 700 feet above
the sea, a large silicified tree-trunk was found projecting from the
soil, and therefore above the 250 feet of basalt which there caps
the Cape.

Vol. 53.| ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 509

It is difficult to assign any age to this wood. It is possible that
a Tertiary basalt overwhelmed forests of pines growing at that
time, and that the same kind of trees subsequently grew on the
surface of the sheets of basalt. Or it may be that some already
existing plant-beds were invaded by the intruding basalt, in which
case the moving mass might in some instances have passed over,
and in others passed under, the plant-bed ; or there may have been
more than one such bed.

It is well-nigh certain that this silicified wood is not earlier than
Upper Jurassic, for it almost certainly occupies a position above the
Oxfordian fossil-bed; but of this we have no positive proof, seeing
that the beds exposed at Cape Gertrude have yielded no fossils to
indicate their age. It is quite possible, therefore, that some of
this silicified wood may be of Upper Jurassic, Cretaceous, or Tertiary
age. On the whole, it seems most in accordance with the known
facts to regard it as of approximately the same age as the basalts,
which are probably of Tertiary date.

Judging from the report of Mr. Leigh Smith’s visit to Franz
Josef Land,! and Mr. Etheridge’s remarks in the discussion,?
it was thought that the pine-cone, the silicified wood, and the
plant-impressions there mentioned were all from qe horizon;
but no evidence was brought forward proving that such was the
ease. Mr. Carruthers, who examined the pine-cone, was of opinion
that it was of Cretaceous age; and the presence of Cretaceous rocks
in Franz Josef Land rests upon that opinion. It is by no means
clear, however, that the silicified wood is Cretaceous, even if the
evidence of the pine-cone be accepted; but there now seems to
be some doubt as to the age of the cone.

The manner in which this silicified wood is preserved merits
attention ; in some cases the replacement by silica has been so
brought about that the form of the finest tissues is extremely well
preserved, and, being of a dark brown colour, sections under the
microscope show their structure even better than recent wood
(Pl. XLI, fig. 11). The large longitudinal cells of the woody tissue
are clearly defined, as are also the medullary rays which cross
them, but the feature which is the most striking and at the same
time the most characteristic is the well-marked series of discs
(dotted tissue) which are typical of coniferous wood, and are in
this instance large, and arranged in single and double rows in the
cells. Transverse sections show the usual annual rings.

There is much difference in the degree in which the finer tissues
of this fossil wood are preserved, some examples, like that above
described, seeming to have every feature of the original structure
retained, while in others this is nearly or quite obliterated. Some
sections of black flinty fragments which have been examined
have traces of tissue so faint as to leave doubt concerning its
vegetable origin; and there are many intermediate stages between
the two extremes. It may be mentioned also that silicified masses

1 Proc. Roy. Geogr. Soc. n. s. vol. iii. (1881) p. 185.
2 Ibid. p. 147.

510 MESSRS. E. T. NEWION AND J. J. H. TEALL ON [ Dec. 1897;

of vegetable matter other than wood have been collected, but these
may not be of the same geological age. One such block, from
the talus at Cape Stephen, on which there is a leaf of Ginkgo
and a piece of a pine-branch, has already been noticed (p. 506).

The preservation of this wood in close relation to the basalt is

of much interest, for it is not only in Franz Josef Land that there
is this association, but it has been noticed in many other places.
Under very similar conditions wood has been found interstratified
with the basalts of Greenland; the same conditions are present
in the Western Islands of Scotland, where Pinus eaggensis, some-
times silicified and sometimes preserved in carbonate of iron, occurs
under the Scuir of Eigg, as deseribed by Hugh Miller in the
‘Cruise of the Betsy’; and coniferous wood was found by Sir A.
Geikie under the basalt in the Island of Canna.’
' The common occurrence of silicified wood on the shores of Lough
Neagh, Ireland, is well known, and is stated to be derived from
clays which are there found under the basalt.’ Silicified wood has
also been met with in the basalt of the Giants’ Causeway.

It would be interesting to know whether similar conditions have
existed in other places where silicified wood has been so abundantly
found, such a near Cairo, in Antigua, in Arizona, in Tasmania,
etc. In some of these localities volcanic conditions do obtain,
but further information as to the precise relation of the silicified
wood to the volcanic rocks is desirable.

In addition to the specimens above described the collection con-
tains material from the surface of a floe, 48 miles south of Bell
Island, and from the under-surface of an iceberg found, tilted up,
off Eira Cottage.

That from the floe is a brown mud composed of extremely fine,
brownish, amorphous particles, with which a few diatoms are
associated. A partial analysis gave the following result :—

SiO3, j annus daventilgteeedah ates 49°88
DIOS boats cerca eer "28
ALLO), onc saeneeostvanecn qatar 18:06
RESO)" eswncsisenterea sees 9°14
Cas | oicicco iG, sae teetees 3°00
MeO) oh psaeces Baeseemenouetes 2:20
Loss on ignition ......... 13°88

96°44

The material from the iceberg is a greenish sand, containing shells
and fragments of Mya truncata, Balanus concavus, Balanus porcatus,
and Saaicava arctica; also some small subangular pebbles. The
sand is principally composed of quartz and felspar, but contains
also hypersthene, zircon, iron-ores, rutile, tourmaline, and garnet.

1 Quart. Journ. Geol. Soc. vol. li. (1896) p. 362.
2 See W. W. Watts, ‘Guide to the Collections of Rocks and Fossils in the
Museum of Science and Art, Dublin,’ 1895, p. 69.

Vol. &2. ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 511
3

The subangular pebbles are formed of basalt, sandstone, and black
radiolarian chert. A section of the chert has been examined by
Dr. G. J. Hinde, F.R.S., who has kindly furnished us with the
following description :—

‘The thin section of the small rolled pebble of light-
coloured chert from Franz Josef Land is seen under the microscope
to be filled with casts of radiolaria. The structure of these
organisms, as is usually the case, is now entirely obliterated, and
they appear as minute transparent bodies with circular, oval, or
discoidal outlines in the cherty matrix. Most of them are smooth,
but a few have projecting spines. They range from 0-06 to
0:19 mm. in diameter ; in general, the forms are relatively smaller
than those usually met with in chert. Judging from their out-
lines, several genera are represented in the section; the most
numerous are the simple round and oval forms belonging to Ceno-
sphera and Cenellipsis, and the rarer spined ones may be probably
referred to Xiphostylus and Dorysphera. Though the horizon of
the rock from which this pebble comes cannot be _ positively
determined from these imperfectly preserved radiolaria, it is not
improbably of Paleozoic age. The character of the chert itself
is precisely similar to that of the radiolarian chert of the
Paleozoic rocks of Devon, Cornwall, and the South of Scotland.’

It is a curious circumstance that among the few specimens
brought from Joinville Island in the Antarctic region, south of
the Falkland Isles, was one of radiolarian chert; thus this rock
has been found, though not zm situ, in the most northerly and most
southerly lands yet visited.

Rocks showing cone-in-cone structure are very abundant near
Cape Flora, and have been found at several localities. Numerous
specimens have been collected, but unfortunately not one of them
was found in place, so that the exact horizon from which they come
cannot be determined. As they are found all round the Cape, and
sometimes high up on the talus, it is probable that they form a
band or bands situated not far below the basalt. ~

The rock is an argillaceous limestone, and the carbonate, which
has produced the structure by its attempts to crystallize under
unfavourable circumstances, is rich in lime and poor in iron and
magnesia."

9
VI. Tue RELATIONS OF THE VARIOUS FossitirEROUS Horizons.

In order to give some idea of the relations of the various beds
of fossils above noticed, and of their probable place in the geological
sequence, a vertical section (fig. 4) has been made of the strata at
Cape Flora, relying upon the various heights above the sea, at
which the different beds are said to occur, for the position of these

1 See G. A. J. Cole, ‘On some Examples of Cone-in-cone Structure,’ Min. -
Mag. vol. x. (1892) p. 136.

512 MESSRS. E, T. NEWTON AND J.J. H. TEALL ON [ Dec. 1897;

beds in the section ; but it must be remembered that the figures
supplied to us are only approximately accurate, and are liable to
correction by further measurements.

The sedimentary strata in the south of Franz Josef Land are
believed to be regularly horizontal, with only a slight dip to the
north-east, and consequently within the area of Cape Flora it is
unlikely that there will be any serious variation in the height of
the same bed at different parts of the cliffs.

Cape Flora is said to be 1100 feet high; the upper 500 feet is
basalt, while the lower 600 feet is made up of sedimentary rocks,
covered for the most part by talus. The base of the basalt is
thus placed at 600 feet above the sea, and the positions of some of
the beds, as we shall sce, are reckoned by their distance below the
basalt. Thin beds of basalt are said to occur in the clay-beds, but
as the exact position of these is not stated they are left out of the
section ; and for the same reason the seams of coaly lignite, noticed
in these clay-beds, are omitted.

There is one horizon, however, the age and position of which are
definitely known : itis that which occurs at the back of Elmwood, at
about 50 feet below the base of the basalt. At this spot a bed
(No. 3) was found in situ, and from it a small ammonite was obtained,
which is probably Ammonites Tchefkint. In the watercourse
below this exposure similar ammonites were found, together with
A, modiolaris and A. macrocephalus (see p. 496). These suffice
to settle the age as Lower Oxfordian and probably the equivalent
of our own Kellaways Rock ; and although only one ammonite was
really found im situ, yet it is sufficiently certain that the others, if
not from the same place, came from beds but little lower in the
series. Similar fossils to these occur in the talus at many places
around Cape Flora, showing that the same beds in all probability
occur all round the Cape.

The belemnites which were collected during the Hira Expe-
dition by Mr. Grant, apparently on Mabel Island and said to be
of Oxford Clay age, probably belong to this horizon.

How much of the beds above and below the Ammonites macro-—
cephalus-horizon is to be included in the Lower Oxfordian one
cannot sey, no distinctive fossils having been found. The thin
bands of shale (No. 2) which occur just above the A. macrocephalus-
horizon and close under the basalt have yielded no fossils.

On the north side of Cape Flora, at a height of about 700 feet,
the bed with plant-remains (No. 1) occurs; it is said to be 2 situ,
and overlying a mass of basalt projecting through a glacier.
This locality is about a mile north-west of Elmwood—that is, on
the supposed strike of the beds; it is therefore included in the
section at the height given. It is difficult to decide whether this
plant-bed should be included in the Oxfordian or not. Dr. Nathorst’s
opinion, that it is of Upper Oolite age, carries great weight; but
if this be correct, then there would seem to be only 150 feet of
strata between the Lower Oxfordian and the Upper Oolite. More-

[To face p. 512.

_»F THE WESTERN PA

== SSS SS
= San a

Cape Stephe
o the distant cliffs to t]

Bell Island.

{ DATA SUPPLIED, 8),

1300 feet
above
sea-level.

1100 feet.

Glacier-slope.
Plant-bed over basalt.
700 feet. }.

600 feet.
East of Elmwood,
bands of shale.
Elmwood water-
course.

Windy Gully. 300 feet.

Elm- feet.

/ 600 Pig west 30t040
o
wood,

S

Quart. Journ. Geol. Soc. Vol, LIII.

a

[To face p. 512.

Cape Crowther. Cape Grant.

Tween Rocks,

Cape Stephen.

Mabel Island, Bell Tsland,

[Ice-pack extends from the distant cliffs to the sea in the foreground, The dark masses are basalt-crags, ]

Fig. 4.—Verrican SECTIONS, COMPILED FROM DATA SUPPLIED, SHOWING THE PROBABLE STRATIGRAPHICAL SUCCESSION IN FRanz Joser LAnp.

Between Oupe Grant
and
Cape Stephen.

700 feet
above
sea-level.

ra
aes
A

oe

=]
id

Zs

i

450 feet,

Slab with poe
plant-remains
on talus at by
the 300 feet level. talus.
100 feet. Coal.
7 feet. Bituminous Shale.

theca, ete.

Plant-bed w. Phyllo-

Cape Flora.

1300 feet
above

sea-level.
Tee.
1100 feet.
Basalt
500 feet
thick.

al.
ert

cee

re

Glacier-slope.
Plant-bed over basalt.
700 feet.

1, Plants, Ginkgo, etc.

600 feet.
Tast of Elmwood, b—
bands of shale.
Elmwood water-
course,

2,

=

Amm. Tchefkini (2)
in place, A.macro-
cephalus, A. mo-
diolaris, etc.

Windy Gully. 300 feet, == m4. Amm. Ishmx, Be-

lemnites.

Avicula, Belemnites.

Sea-level.

Cape Gertrude.

800 feet
above
sea-level. [Az

basalt.
720 feet,

Hidden by talus.
612 feet.

No fossils, Nodule-bed.

Seventy thin beds,
sands, ignites,
ete,

400 feet,

ag
4
47 '
ny i
st
4 -
ry
j
pA
‘
P
‘
hal
.
¢ i
t
bi as
, a
si-3
,
Nr
a .
‘ ; y H / j / ‘ ©
ra Pe rena ’ e's Wy ae te i r he
, . ae 1 eu, Aredia | iri
i \ : Dh Devt. Valero ei er

Mol.53.| ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 513

over, if the basalt is intrusive, then the two beds (1 and 3) may
originally have been nearer together than they are now. We must
await further evidence before this point can be fairly discussed ;
in the meantime these plant-bearing shales are the highest fossili-
ferous horizon that has yet been found in place in Franz Josef
Land.

The specimens of Ammonites Ishme discovered at Windy Gully,
at 300 feet above the sea,’ are believed by Dr. Kcettlitz to have been
in place—that is to say, he is of opinion that they belonged to
the bed on which they were found. This horizon, therefore, is placed
in the section at 300 feet above the sea, and is thus 250 feet below the
Ammonites modiolaris-bed, but this distance may be too great. The
ammonites and belemnites of this bed are not of the same species as
those found in the Ammonites macrocephalus- and A. modiolaris-
horizon; and it is quite possible that we may have in this A.
Ishme-bed a representative of another formation, perhaps of the
age of the Cornbrash.

The lowest horizon seen at Cape Flora is the bed exposed at
about 30 to 40 feet above the sea, a little to the west of Elmwood
(No.5). Except for the fact that this bed is situated some 250 feet
lower in the series than the place where A. Jshme was found,
there is nothing to give a clue to its geological horizon. The large
Avicula has not been identified, and the belemnites, although
resembing those found with Ammonites Ishmc, are not perfect
enough for identification.

The numerous thin beds (No. 6) at Cape Gertrude, that occur
at a height of from 200 to 400 feet above the sea, having yielded no
fossils to indicate their age, cannot be correlated with the section at
Cape Flora, and it is only their elevation above the sea that points
to a possible correspondence with the Ammonites macrocephalus- and
A, modiolaris-series.

We now come to what seems to be the lowest horizon from
which fossils have been collected in Franz Josef Land—namely,
the plant-bearing sandstone at Cape Stephen (No. 7), which was
also found exposed farther south-west, towards Cape Grant. As
this locality is more than 20 miles west of Cape Flora and the
structure of the intervening islands is not known, it is hazardous
to attempt to correlate the beds at the two places. But, at the same
time, if the strata of the south of Franz Josef land are uniform
in their north-easterly dip, then, as this plant-bed is near the sea-
level at Cape Stephen, we should expect to find it or its equivalent
at some distance below the sea at Cape Flora; and the possibly
Lower Oolite age of the plants points to a similar position in the
series. On the other hand, as already pointed out (p. 505), these
beds may be of much greater antiquity.

The presence of a plant-bed at the top of these Oolitic strata of
Franz Josef Land, and the occurrence of lignite-beds in many
places below, show that estuarine, if not indeed freshwater, con-

' See footnote, p. 500.
@.3.G. 8. Nos 212. 2 M

514 MESSRS, E, T. NEWTON AND J. J. H. TEALL ON [ Dec. 1897,

ditions must have prevailed during a large part of the time when
they were being deposited; but, on the other hand, the horizons
with Ammonites and Belemnites point to times when marine
depositious intervened.

Strata of Oolitic age have been met with in Spitsbergen by
Prof. Nordenskiold, and the presence of Ammonites triplicatus
would seem to indicate that they belong to higher beds than have
been recognized in Franz Josef Land, unless indeed they correspond
with the upper plant-bed of Cape Flora.

More recently two species of Jurassic ammonites have been recog-
nized from Spitsbergen by Dr. Fraas,’ namely Ammonites triplicatus
and A. cordatus, from which one can only conclude that beds are
present which in Britain would be called Upper Oxfordian.

Numerous Jurassic fossils were collected by Prof. Nordenskiold
in Novaya Zemlya and have been described by Prof. Tullberg.’
Among these Ammonites alternans is found, thus indicating the
presence of beds of Kimeridgian age in that country.

The question of the age of the silicified wood has already been
alluded to (p. 509), and little further can be said. The occurrence
of this wood below the basalt and near to probable Jurassic deposits
shows that some of it may perhaps be of Jurassic age; but it may
equally well be of Cretaceous or Tertiary date. Even if future
discoveries confirm the supposed Cretaceous age of the pine-cone
from Bell Island, this will not necessarily prove the silicified wood
to be of the same age.

The possibility of Tertiary beds being present is shown by the
silicified slab from Cape Stephen, the Ginkgo seeming to be the
same as G'. reniformis, which is from beds believed to be of Tertiary
age.

The plant-remains found near Cape Richthofen may lkewise
be of Tertiary age, as already mentioned (p. 507), but the evidence
is so slender that it must be taken rather as a suggestion
of something to be looked for in the more northern parts of
Franz Josef Land than as a proof of the presence of beds of so late
adate. The fact that beds with abundant plant-remains of Tertiary ©
age have been found in Spitsbergen shows that similar deposits may
be expected here. It will be remembered that the specimens from
Cape Richthofen were found upon a high lateral moraine, and
therefore presumably were derived from beds directly above this
moraine, or it may be were brought from a distance; in either case
it is quite possible that they may yet be found zn stu. The plant-
remains themselves have a very recent look, but it is hardly likely
that they can be more recent than the Glacial Period; indeed,
Mr. Clement Reid’s opinion (p. 508) goes far to show that they are of
neither recent nor Pleistocene age, but must be referred to the

1 “Sketch of the Geology of Spitsbergen,’ 1867, p. 27.

2 Neues Jahrb. 1872, p. 203. See also Raymond & Dollfus, ‘Géol. Spits-
bergen,’ Feuille des Jeunes Naturalistes, 1897, Nos. 286, 287, 288.

° <Verstein. Nowaya Seinlya,’ Bihang till Svenska Vetenskap. Akad. Handl..
vol, vi. (1880) pt. ii.

}

Yok '53:] ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 515

Tertiary period. These plants, however, are so poorly preserved,
and their place of origin is so uncertain, that we can only hope for
additional specimens which may throw light upon this interesting
but obscure question.

VII. Conciusron.

In conclusion, we may perhaps be allowed to sketch out briefly
the salient features in the geological history of Franz Josef Land,
so far as this can be done in the light of our present knowledge.
Passing over the plant-bed at Cape Stephen, the age of which is
uncertain, the first event of which we have any record is the
deposition of a series of shales and sandstones containing plant-
remains, beds of lignite, and other evidences of littoral or estuarine
conditions. Intimately associated with these shallow-water deposits
are some purely marine beds, the age of which is placed beyond all
doubt by the occurrence of such well-characterized zonal fossils as
Ammonites macrocephalus and A. modiolaris.

Owing mainly to the brilliant researches of Neumayr,' it is now
generally recognized that the Jurassic sea reached its greatest
extension in the present land-areas during the Callovian and
Oxfordian periods. Hydrocratic and geocratic movements alter-
nated during Jurassic times, with a decided balance in favour of the
former, and a recession of the coast-line towards the north. Even
in the North of Scotland we find no decided evidence of the
proximity of land during the Oxfordian period, although the lower
portions of the Jurassic formation are represented by littoral and
estuarine deposits.”

Under these circumstances the discovery of A. macrocephalus-beds
in Franz Josef Land in association with plant-bearing strata is of
special interest. It extends the range of this ammonite several
degrees towards the north, and shows, in all probability, that
during the period of its:existence a coast-line lay somewhere in this
direction. Marine deposits of Callovian and Oxfordian age are now
known to range from Sutherland to Cutch and from Franz Josef
Land to the North of Africa; and A. macrocephalus is one of the
most widely distributed of all Jurassic ammonites.’ The soft
Jurassic sediments were subsequently covered up and preserved
from destruction by vast flows of basaltic lava; and it is not a little
remarkable that rocks of the same general period have been
preserved in the same way in districts so far removed from Franz

1 «Die geographische Verbreitung der Juraformation,’ Denkschr. d. k. Akad.
d. Wiss. Wien, vol. 1. (1885) pp. 57-142.

2 J. W. Judd, ‘The Secondary Rocks of Scotland,’ Quart. Journ. Geol. Soc.
vol. xxix. (1873) p. 164, & vol. xxxiv. (1878) p. 726.

3 It not only occurs in Ceutral and Southern Europe, Northern Russia, and
Franz Josef Land, but also in Cutch (Waagen, Pal. Indica, ser. ix. vol. i. 1873) and
Bolivia (Steinmann, Neues Jahrb., Beilage-Band i. 1881, p. 239). It has also been
recorded from Western Australia (Moore, Quart. Journ. Geol. Sec. vol. xxvi.
1870, p. 226), but Newmayr throws doubt on the identification (op. cit. p. 118).

2mu 2

516 MESSRS. E. T. NEWTON AND J. J. H. TEALL ON [ Dec. 1897,

Josef J.and as the North-west of Scotland’ and Abyssinia.” We
have already pointed out that Dr. Nansen refers the basalt in part
to the Jurassic period; but in view of the fact that the basalts of
the West of Scotland were at one time supposed to be of the same
age, for reasons similar to those relied upon by him, this conclusion
cannot be regarded as definitely established. At the same time it
is important to notice that, if we except the North of Ireland, the
Upper Cretaceous period is unrepresented, or but feebly represented,
by sedimentary deposits in regions like the Deccan of India and the
high plateaux of Abyssinia, where basalts are extensively developed.
It is therefore quite possible that the vast outpourings of basic lavas
which have given a special character to extensive areas of the
earth's surface * may have commenced in pre-Tertiary times.

The present configuration of the archipelago of Franz Josef Land
(see fig. 3, facing p. 512) conclusively proves that it is formed of the
fragments of an old plateau. The land frequently ends off in high
cliffs, capped with sheets of basalt which must have extended far
beyond their present limits. When one compares the topography of
this district with that of the Ferédes and the West of Scotland, one
is inclined, notwithstanding the immense tracts of water which now
separate these localities, to ask whether they may not at one time
have been continuous, and whether the northern portion of the
North Atlantic, as suggested by Suess,* may not be of comparatively
recent origin.

But whatever answer may be given to this question, it is clear
that at the close of the volcanic period the various islands of Franz
Josef Land were united and formed part of an extensive tract
of land. This land was subsequently broken up, partly, in all
probability, by the sinking of certain areas along lines of fault, and
partly by denudation.

The final stages in the history of the district are represented by
the raised beaches, which prove that this region, like so many other
portions of the extreme north, has quite recently been under the
influence of a geocratic movement.

EXPLANATION OF PLATES XXXVII.-XLI.

PuateE XXXVII.

Fig. 1. Basalt from talus, Cape Flora. x 20. The figure shows labradorite,
ophitic augite, and interstitial matter, with which some magnetite is

1 J. W. Judd, ‘The Secondary Rocks of Scotland, Second Paper, Quart.
Journ. Geol. Soc. vol. xxx. (1874) p. 220.

2 Aubry, ‘ Observations géologiques sur les Pays Danakils, etc., Bull. Soc.
géol. France, ser. 3. vol. xiv. (1886) p. 201.

3 The Deccan traps cover an area of about 200,000 square miles, ‘ Geology
of India, 2nd ed. 1893, p. 256.

4 * Are Great Ocean-Depths Permanent?’ Natural Science, vol. ii. (1893)
p. 185.

Vol53-] ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 517

associated. The magnetite cannot be distinguished from the inter-
stitial matter in the figure. [F. 318.]

Fig. 2. Amygdaloidal basalt from the talus, Cape Flora. x 10. Labradorite,
augite, palagonite, and calcite. In this case no magnetite can be
recognized under the microscope ; the whole of the iron-oxide appears
to bave remained undifferentiated. The interstitial matter occurs also
as the infilling material of an irregular cavity, the centre of which is
occupied by calcite. [F. 321.]

Fig. 3. Olivine-basalt with chrome-diopside. x 10. From the under-surface of
an iceberg off Hira Cottage. The chrome-diopside occurs as a pheno-
cryst with a zone of inclusions near the margin. The large black
inclusion is of a greenish undetermined substance—not magnetite.
Olivine is not seen in the figure. [F. 324.]

Fig. 4. Another portion of the same section. xX 20. The interstitial matter
in this rock has been devitrified during consolidation, and is crowded
with grains and skeleton-crystals of magnetite, which can be recognized
in the figure. [F. 324.]

Fig. 5. Quartz-bearing basalt. x 50. From the under-surface of an iceberg,
found tilted up in De Bruyne Sound. Calcite surrounded by a zone of
augite-microlites. The clear patch near the outer margin of the zone
is also formed of calcite. The main mass of the rock is formed of
wicrolites of felspar, augite, and magnetite. [F. 343.

Fig. 6. Phosphatic nodule from Windy Gully, Cape Flora. x 16. [F. 336.]

[The numbers in square brackets refer to the collection in the Museum
of Practical Geology. |

Puate XXXVIII.

Fossil plants from the north side of Cape Flora, Northbrook Island,
Franz Josef Land, 700 feet above the sea.

Fig. 1. Ginkgo polaris ?
2

ats ” ”

3. As ae

4, . Siuerie@s
5

we ” ; ” ”
6,7 & 8. Pine-seeds.
= » cone.
10. Baiera?

11. Fieldenia?
12. Podozamites ?

13 & 14. Thyrsopteris sp.

Puate XXXIX.

Figs. 2, 5, 5, 7, 8 & 15 are of specimens from the watercourse in the talus
at the back of Elmwocd, Northbrook Island, No. 5 being found zn situ.
Figs. 4, 6, 10, 11, 12, 138 & 14 are of specimens from the western end
of Cape Flora. Figs. 1 & 9 from Cape Flora.

Figs. 1&2. Ammonites (Macrocephalites) macrocephalus.
3

# ss : var.
4 & 6. Ammonites (Cadoceras) Tchefkini ?

; a2 E 2 Found in place 50 feet below the basalt.
7,8 &9. Ammonites (Cadoceras) modiolaris.

10. i , * flattened variety.
11,12 & 13. Belemnites Panderi.
14. - i Piece of large specimen,

15. Gorgonia ¢

O18 MESSRS. E, T. NEWION AND J.J. H. TEALL ON [ Dec. 1897,

Puatse XL.

Figs. 1-3. Ammonites from Windy Gully, east of Elmwood, Northbrook
Island, found on a shoulder of rock 300 feet above sea- ‘level believed
to be in place.

HE: e Anmonitls Mecrnaphalites) Ishme, var. arcticus.

pas 2. oe mM », inflated variety with coarser ribs.

ple: * 3. 5 Pr - ,,. The exterior of this shell is almost

‘ devoid of ribs.

4. Avicula sp., from west of Elmwood, 30 or 40 feet above sea-level, and
believed to be in place. The outline shows the probable size. Other
fragments indicate still larger shells.

Prats XLI.

Figs. 1-9. Plants collected from beds én sitw near the sea-levei, at a spot

called ‘ Tween Rocks’ between Cape Grant and Cape Stephen.
Figs. 1-3. Phyllotheca like Equisetum columnare, Phil.

4&5. Zamivpteris ? like glossopteroides. Mar gins imperfect.

6 & 7. Rhiptozamites! near to Gepperti.

8. Anomozamites ?

9. Asplenium ef. whitbiense.

10. Portion of silicified slab of plant-remains from Cape Stephen, 300 feet
up the talus, containing strap-like leaves with (a) Ginkgo reniformis ¢
and (b) Pinites.

11. Magnified section of silicified wood from Northbrook Island, showing
the dises of coniferous wood.

Discussion.

Dr. J. W. Grreeory was glad that the Authors confirmed
Mr. Etheridge’s determination of the beds as Oxfordian—a con-
clusicn based on the collections made by Mr. Leigh Smith. The
simplicity of the series around Elmwood was probably due to its
occurrence in the heart of a great plateau-area; whereas in
Western Spitsbergen the series was more varied, owing to its

having been formed on the oseillating border of the land-area.

Hence it is probable that the outlying islands of the Franz Josef
archipelago, such as Oscar Land and Petermann Land, will yield
a richer series of deposits.

The main mterest of the stratigraphical portion of the paper was
centred in the history of the Arctic Jurassic sea; but the speaker
thought that Neumayr’s fascinating theory, to which reference
had been’ made, was now quite aitenable, The relations of the
Jurassic series in Franz Josef Land to those of the Northern
Petchora basin were very significant. He understood that Belemnites
Panders was typically Kimmeridgian and Sequanian. He thought
that all Fellows of the Society would be grateful to Mr. Harmsworth
for his munificent generosity, and to the Authors for their very
careful and thorough study of the material colleeted.

Mr. W. W. Warts enquired as to whether it was absolutely
certain that the basalts were other than of Tertiary age. In

—

ES —

PES DOR AVII.

Soc., VoL. LIII..

QuART. JOURN. GEOL.

RockS FROM FRANZ JOSEF LAND.

Gnee Jotrneceol Sec Val GUurrl Acme

12

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FRANZ JOSEF LAND FOSSIL PLANTS.

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JURASSIC FOSSILS.

Quart. Journ.Geol.Soc Vol. LI] Pl. XXXIX.

Mintern Bros imp.
A-T.Hollick del. et lith.

FRANZ JOSEF LAND JURASSIC FOSSILS.

AT /Hollick.del.etlith.

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Quart. Journ.Geol Sec Vol. LIT PL XL.

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FRANZ JO2a2e aie |

Quart. Journ Geol. Sec Wot lLiiPl xe

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FOSSIL PLANTS.

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Quart. Jurn.Geol. Soc Vol. Lill Pl. XLI.

A T.Hollick delet lth Mintern Bros. imp-

FRANZ JOSEF LAND FOSSIL PLANTS.

Noles 3-] ROCKS AND FOSSILS FROM FRANZ JOSEF LAND. 519

Spitsbergen, Ireland, and Scotland exactly similar lavas were of
Tertiary age.

Mr. G. C. Crick agreed with the Authors as to the age of the
cephalopoda exhibited, and with regard to Dr. Gregory’s question
respecting the occurrence of Belemnites Pandert with the ammonites
referred by the Authors to A. macrocephalus and A. modiolaras,
suggested that possibly beds of a somewhat higher horizon than that
indicated by the Authors were also present.

The Presrpent, Prof. H. G. Seetey, Dr. G. J. Hivoz, Mr. A.
Monteriore Brice, and Prof. Lawson also spoke.

The AvrHors, in reply, said that they did not srggest that the
basalts were of Jurassic age. They thought that these were probably
related to the Jurassic rocks in the same way as in the north
of Skye. They were quite aware of the probable occurrence
of faults in the district, but could not give any direct evidence on
this point.

With regard to the Upper Jurassic age of the higher plant-
bearing beds, they were pleased to be able to support the view of
Dr. Nathorst. They thought that the range of Belemnites Panderi
would prove greater than was supposed.

In conclusion, they desired to express their appreciation of
the careful way in which the specimens had been collected and
labelled—a result doubtless in large measure due to the energy
and organizing skill of the Hon. Secretary of the Expedition,
Mr. Montefiore Brice.

520 MESSRS. C. I. GARDINER AND 8. H. REYNOLDS on [ Dec. 1897,

35. An Account of the Portraine Intrer (Co. Dustin). By C. I.
Garpiner, Esq., M.A., F.G.8., & 8S. H. Reynozps, Esq.,
M.A., F.G.S8. With an Apprenpix on the Fosstts by F. R.
CowrEr Reep, Esq., M.A., F.G.S. (Read June 9th, 1897.)

[Puates XLII & XLII.)

ConTENTS.
Page
iL. hatroditement. 250. bs ct eat ie cco seats Oe eee ee a ee 520
II. Description of the Area and its Geological Structure ......... 521
IIT. The Igneous and Associated Rocks at the Northern End of
tlre Mages ese denna or aod cnatenpacecemecnp te tesa cee eae eee 521
IV. The Igneous Rocks at the Southern End of the Inlier ...... 525

(a) Those exposed along the Shore.
(6) Those exposed Inland.
V..- Phe dittmestome sSeries' 2.) de eats tac en va ce -siiesage + Cee eee 527
(a) The Coast-section North of the Grits.
(6) The Coast-section South of the Grits.
(c) Exposures Inland.

WI. DhesGrit Series! ceg:ste. stot Pade ieee cc iee ss <n eee 531
VII. The Conglomerates due to Earth-movements .................. 531
VIL. Summary and ‘Conclusions. : 5c... ces. e..ace+-0-:8 5s eee eee 534
Appendix ram the Mosse. oie. can. cca eine none se oeiniaceee eee ener 535

I. Inrropucrion.

Tur coast of County Dublin is well known for the variety and
interest of the rocks exposed along it, but there is probably no part
of it more interesting than that in the neighbourhood of the village
of Portraine, some 14 miles north of Dublin itself. Here occurs
an inlier of pre-Devonian rocks which prove the occurrence in
the district, during Bala times, of much volcanic action and of
reef-building corals. The interest attaching to the rocks and the
difficulty of interpreting their meaning are increased by the great
amount of disturbance which has gone on and has given rise to
extensive developments of conglomerate-like beds.

Volcanic rocks, which are certainly of the same age as those at
Portraine, and coarse conglomerates, occur on Lambay Island, some
3 miles out to sea, and we hope to give some account of these at
no distant date.

We were led to examine the beds at Portraine from a wish to
compare them with the Bala Beds occurring in the neighbourhood
of Kildare, which we described last year.’

The Portraine area has, perhaps, hardly received so much attention
from geologists as it deserves. The first description is that given by
H. B. Medlicott?; a brief account is given by G. V. Du Noyer, in
the Memoirs of the Irish Geological Survey, the memoir including

1 Quart. Journ. Geol. Soc. vol. lii. (1896) p. 587.
? Journ. Geol. Soc. Dublin, vol. v. (1853) p. 265.

Volt 53. THE PORTRAINE INLIER (CO. DUBLIN). 521

a list of some fifty fossils determined by W. H. Baily'; later Prof.
Cole writes of the area in his articles on ‘ County Dublin, Past and
Present’?; while the most recent account is that by Prof. Sollas,
written for the visit of the Geologists’ Association to the district
in 1893.%

Il. Description oF THE AREA AND 1TS GEOLOGICAL STRUCTURE.

The area with which we are concerned forms a blunt-ended
promontory, limited on the north by the estuary on which Rush
is built, and on the south by that on which Malahide is situated.
The pre-Devonian rocks are bounded on the east by the sea; on the
north by the waters of the Rush estuary; on the west by a coarse
conglomerate, referred by the officers of the Geological Survey to the
Old Red Sandstone period; and on the south by an area of blown
sand. Our account of them deals mainly with the coast-section,
for inland exposures are scanty, the country being much covered
by drift.

Two martello towers have been built on the promontory, the
northern one being used as a Coastguard station, and they will be
frequently referred to, as they form convenient landmarks. (See
Map, Pl. XLITT.)

Geologically the rocks forming the inlier are divisible into several
well-marked groups. At the northern end is an area of volcanic
rocks, succeeded to the south by an area of limestone and shale,
which is followed by an exposure of grits. Then comes a smaller
- development of limestone and shale, and, finally, at the southern
end of the inlier occurs a second area of volcanic rocks. Owing
to the great amount of faulting and folding which has taken place,
the area has been made very complicated. Not one of the groups
of rocks that we have mentioned can be seen to rest cenformably
on another, the junction being apparently in every case a faulted
one. The divisional plane between the grit series and the limestone-
and-shale series is, wherever visible, a thrust-plane, marked by the
development of most interesting conglomerates due to earth-move-
ments.

Although we have no definite proof of their age, the grit series
apparently forms the newest group, and the volcanic rocks the
oldest, of the inlier, the district as a ‘whole forming a much
denuded half-syncline.

III. Tae Ienrovs anp Assocratep Rocks at tHE NorRTHERN END
OF THE INLIER.

' At the north-western corner of the inlier the coarse quartzose
conglomerate mentioned above is seen dipping N.W. at 35°, and from
beneath it appear with a south-easterly dip a series of purple and
green andesitic rocks which form the foreshore up to, and just beyond,

1 Explan. Mem. Sheets 102 & 112 Geol. Surv. Irel., 2nd ed., Dublin, 1875.

2 «Trish Naturalist,’ vol. i. (1892) p. 31.

3 «The Geology of Dublin and its Neighbourhood,’ Proc. Geol. Assoc.
vol. xiii. p. 91.

o22 MESSRS. C. I. GARDINER AND 8, H. REYNOLDS on [ Dec. 1897,

the farm at the north-eastern corner of the area. These rocks
in a hand-specimen are seen to have a compact groundmass, and
frequently show porphyritic felspars of no great size. They are
often slightly and sometimes extremely amygdaloidal, the amygdules
being formed of pink calcite. Veins of epidote are of frequent
occurrence, and jaspers are numerous at certain spots.

Some twenty sections of rocks from this portion of the coast have
been examined microscopically. They are all seen to be from
andesites which have undergone considerable alteration, accompanied
by the formation of various secondary minerals.

The groundmass is always fairly prominent,-and in some cases
very prominent indeed ; it is invariably much altered, its original
constituents being replaced by chlorite and epidote. In many
sections the groundmass contains numerous needle-shaped crystals
of felspar which extinguish approximately parallel to their lengths,
and occasionally show well-marked flow-structure. Jron-ores are
abundant, some slides showing magnetite, others leucoxene or
hematite, while in some iron pyrites occurs as well.

The porphyritic constituents are (1) felspars, probably ee
dorites, occurring as fair-sized crystals, which, though much altered,
worn, and replaced, still at times chee twinning ; (2) augiter,
now entirely replaced by calcite or by a brown mineral traversed
by veins of chlorite; and (3) apatite, which has been observed
in only one section of a rock from this area, though it has been
frequently found in similar andesitic rocks occurring on Lambay
Island.

The amygdules, as previously mentioned, are formed for the
most part of calcite, but some contain chlorite enclosing little
patches of silica.

Immediately north of the farm, at the point where the coast-line
turns to the south, two somewhat different types of rock occur, one
of which probably forms a dyke in the andesites, as its strike does
not run in the same direction as do those of the andesites.

The dyke, a foot or so in breadth, runs in an east-and-west
direction, is of a light green colour, and shows large, greenish-white,
platy felspars. It is identical in character with some of the
Lambay porphyrites, which are sometimes intrusive and sometimes
interbedded. Under the microscope it shows an extensive ground-
mass, composed of a yellow decomposition-product and felspar-
microlites, and porphyritic felspars, fairly fresh but much worn at
their edges.

The second rock, whose strike, like those of the other andesites, is
south-west and north-east, is noticeable from the very large
amount of red iron-oxide which is aggregated round the felspars
and vesicles. Small felspars are to be seen in the groundmass,
most of them much altered. Porphyritic felspars are scarce, while
patches of a light orange-brown material probably represent por-
phyritic augites.

A little farther on, just at the east side of the corner, is a second

Vol. 53.] THE PORTRAINE INLIER (CO. DUBLIN). 523

mass of coarse rock, similar in character to the dyke above
mentioned. It appears to be intruded into the surrounding ande-
sites, portions of which are caught up and included in it. It
contains in some parts numerous jaspers.

Farther to the south-east a small thickness of light-green andesite
is seen dipping S8.E., at an angle of about 45°; and then, after
a gap in the exposures, about 2 feet in width, there comes on
a remarkable conglomerate which occupies the foreshore for the
next 150 yards. The dip of this bed is to the 8.E. at 45°, that
is, in the same direction and at the same angle as the andesite
below it, and this fact, together with the absence of any trace of
crushing in either rock near their junction, makes it practically
certain that the conglomerate is not faulted against the andesite.

The conglomerate has a matrix which is at first a dark ashy
shale, including many angular fragments, of various sizes, of ash,
andesite, and shale; and here and there small veins of calcite traverse
the rock. The large included blocks consist mainly of limestone or
ash, very few pieces of grit or of lava being seen in the lower
portions of the rock. Several varieties of limestone occur—a red,
somewhat horny type, an earthy type, crowded with fossils, and an
ashy type. The ashes are mostly of a calcareous nature, several
degrees of coarseness being represented. These larger blocks are
always well rounded, and are most of them from 6 to 9 incbes long.

Interbedded with the conglomerate there occurs at one point a
thin band of limestone, and a few feet below it there is a lenticular
mass of black shale.

On going southward, and therefore on ascending the series,
the matrix of the conglomerate is seen to become more distinctly
ashy and yellowish green in colour, while the blocks of limestone
and ash first decrease in number, and then blocks of a coarse
porphyrite and fine andesites become numerous. Occasionally blocks
of very large size are met with towards the centre of the bed, one
(of ash) measuring 5 feet in length.

About 150 yards before the martello tower is reached there
occurs on the foreshore a narrow band of limestone dipping beneath
a few feet of black shale, the latter bed containing very poorly-
preserved graptolites, identified by the officers of the Geological
Survey as Diplograptus pristis. Among the specimens that we
collected Climacograptus Scharenbergr (Lapw.), Diplograptus, and
Dicellograptus have been identified for us by Miss E. M. R. Wood.

The strike of these bands appears to be more nearly east and
west than that of the beds to the north; but farther,out to sea the
previous north-easterly and south-westerly strike is maintained, and
certain well-marked bands of ash are clearly traceable. The ashes
found here were of very varied types. Some were fine, some coarse,
some calcareous, some non-caleareous. Immediately north of these
graptolitic shales the officers of the Geological Survey draw a fault
and state that the beds are there reversed in their dip, but we

524 MESSRS. C. I, GARDINER AND S. H. REYNOLDS on [ Dec. 1897,

could obtain no evidence of this, though at this point signs of dis-
turbance begin which become more marked as we proceed southward.

Beyond the graptolitic shale the rock is still an ashy conglomerate
containing numerous blocks of coarse porphyrite, of ashes of various
types, and of fine andesites, and then as the martello tower is
approached thin bands of limestone, often ashy in their nature,
come to be interbedded with the ashy conglomerate, while bands of
dark-grey calcareous shales also occur, and have yielded, at the spot
marked A in the map (PI. XLIIJ), fossils which have been identified
for us by Mr. F. R. Cowper Reed as Orthis simplex, M‘Coy ?,
Orthis sp., Rafinesquina expansa, Sow., Plectambonites sericea, Sow.,
and fragments of trilobites.

Farther out to sea the ashes, with the interbedded limestones,
are covered by fine green and purple andesites.

The martello tower, forming the Coastguard station, stands on
a mass of limestone which is shaly in places, especially at its base,
and yielded, at the spot marked B in the map, Orthis testudinaria,
Dalm., and Plectambonites sericea, Sow. Though the evidence is
not very clear, this mass of limestone seems to dip landward, and
to be separated by a thrust-plane or fault, with a low hade, from
the volcanic series, whose general dip is, as mentioned above,
seaward. A thrust- or fault-conglomerate of considerable width is
seen at the junction between the limestone and the volcanic series,
both to the east and north-east of the martello tower, while to the
south-east it is not seen.

The volcanic series in the neighbourhood of this plane of thrust
or fault is exceedingly disturbed, the evidence of crushing obtained
in the field being corroborated by microscopic examination, which
shows that, though no mineralogical reconstruction has gone on,
yet displacement of the particles in the groundmass has occurred.
South-east of the martello tower the general strike becomes more
nearly north-north-east and south-south-west than north-east and
south-west. Due south of the tower, exposed only at low tide, is a
band of dark-grey earthy shales, apparently belonging to the
voleanic series. This is indicated in the map (Pl. XLIII) by the -
term ‘ trilobite-shale,’ and yielded

Agnostus agnostiformis, M‘Coy. Phacops Brongniarti, Portl.
(=trinodus), Salt. Trinucleus seticornis, var. portrain-

Ampyz sp. ensis, Var. NOV.

Asaphus radiatus, Salt. ? Orthis sp.

Cheirurus juvenis, Salt. ? Hyolithus sp.

Cybele, sp ? Glyptocystites cf. Logani, Billings.

Tiehas Patis M‘Coy. scoala ‘: ;

Owing to the thrust-plane or fault above mentioned, and a break
in the continuity of the exposure in the sandy bay south of the
tower, it is clear that no regular succession can be traced at the
northern end of the Portraine section between the volcanic series as
a whole and the limestone series.

As will be seen below, a well-marked thrust-conglomerate occurs at

Vol. 53.] THE PORTRAINE INLIER (CO. DUBLIN). 525

two points on the coast south-east of the martello tower men-
tioned above, and, for reasons which we give, we consider it to
be due to earth-movements. It was natural, therefore, that the idea
should suggest itself that this conglomerate north of the martello
tower, which we have just described, should be due to similar
causes. But the observations which we made in the field and
under the microscope forbade us maintaining that idea.

In the first place, there occur in the conglomerate the two bands of
limestone and accompanying shale which we have mentioned. Now,
if the conglomerate owed its existence to earth-movements, it is
difficult to see how these thin bands of limestone and shale would
have preserved their continuity and have shown such slight signs
of being greatly squeezed and fractured, while hard igneous rocks
and compact ash-beds were broken up into fragments.

The very definite nature of the blocks forming the conglomerate at
different points is another objection to the idea. We have men-
tioned that the blocks are at first chiefly of the nature of ashes and
limestones, while at the top of the conglomerate they are largely of
the nature of porphyrites and andesites. The bed on which the
conglomerate rests is an andesite, yet very few blocks of andesite
are found in the lower parts of the conglomerate. No squeezing or
drawing out of the blocks is to be seen in the main mass of the rock.
Microscopic investigation points in the same direction. No minera-
logical alteration is apparent, though this is not a point on which
much stress can be laid, considering the very slight traces of —
such alteration that can be observed in the undoubted thrust-
conglomerates along the coast. But the microscope does not reveal
either any such crushing or drawing out of the materials of which
the groundmass is made as might be expected if this were a thrust-
conglomerate. ‘The groundmass is seen to be of the nature of an
ash, being formed of angular fragments of lavas.

It is true that near the martello tower disturbance does begin to
be visible, and the finer beds overlying the conglomerate show signs
of bending, but this phenomenon appears to be very local and to be
connected with the movement which brought the limestone-and-
shale series under the martello tower into its present position.

If the conglomerate were due to earth-movements, it is difficult
to see why the overlying bands of limestone and ash were not bent
and fractured, so that a passage between the two beds could be
observed.

These are the most important reasons that led us to conclude that
this conglomerate is not one due to earth-movements, but is a
sedimentary conglomerate, with a matrix largely made up of angular
fragments of lava.

lV. Tae Igneous Rocks at tHe SoutHEeRN Enp oF THE INLIER.

(a) Those exposed along the Shore.

At the southern end of the area, near the southern martello tower,
igneous rocks are again exposed on the foreshore. These rocks are

526 MESSRS. C. I. GARDINER AND 8. H. REYNOLDS on [ Dec. 1897,

similar in character to the igneous rocks described above, though
they are much altered, and, especially to the south-west of the tower,
are cleaved and much veined with quartz.

The rocks south of the tower were mapped by the officers of the
Geological Survey as ash; but, though some ash perhaps occurs, they
consist mainly of altered lavas. North of the tower they are certainly
all lavas. In the field they are seen to be green and purple rocks,
the most marked type being a coarse porphyrite with a purple ground-
mass and large green porphyritic felspars. This is described by
the Geological Survey as being faulted against the rocks to the
south, the latter being also described as niiered when they come in
Contnce with the coarse rock, but we found no evidence of either
the fault or the alteration.

Sections of these rocks show a prominent groundmass, as a
rule much altered, but showing small acicular felspars and generally
much iron ore; ilmenite and magnetite are most plentiful, but
hematite and pyrites are sometimes abundant, while chalybite
occurs in one slide. The porphyritic constituents are(1)felspars,
probably labradorite, generally replaced partly or wholly by epidote,
calcite, or chlorite—the alteration having gone so far that some-
times it is barely possible in polarized light to distinguish between
the porphyritic felspars and the groundmass ; and (2) augites, also
much altered.

In many of the rocks calcite has come in largely, and often per-
meates the groundmass as well as fills the vesicles. Other vesicles
are filled with chlorite or with chlorite and quartz, while some >
contain a mineral which is probably serpentine.

The lavas, then, are, like those at the northern end of the saeenth
mainly augite-andesites.

The junction between the igneous and sedimentary rocks is seen
in the sandy bay south of St. Kenny’s Well; its character is not
clear, but it is probably a fanlted junction, like that between
the igneous and sedimentary rocks at the northern end of the
section. It will be described more fully in dealing with the sedi-
mentary rocks. :

(b) Those exposed Inland.

The igneous rocks at the southern end of the section exposed
inland occur in the neighbourhood of Balcarrick House. They
consist of augite-andesites, sometimes amygdaloidal, and similar in
the main to those forming the foreshore, but often in a much fresher
condition, the porphyritic augites being in some cases specially well
preserved. In the groundmass, too, fresh augite-granules are well
seen, and some of the rocks are more nearly holocrystailine than are
any of those on the foreshore. One rock, grey-green in colour, with
numerous large augites visible in a hand-specimen, occurs in the
farmyard of Balcarrick House: this rock, under the microscope, is
seen to have a not very prominent groundmass, somewhat decom-
posed, but still showing small felspar-needles and augite-granules.
Scattered about in this groundmass are numerous porphyritic

Wol..23: THE PORTRAINE INLIER (CO. DUBLIN). 5a
5,

felspars, now so much replaced as to show no trace of twinning,
and also many very fresh porphyritic augites of large size. A
little chloritic material has come in, filling up vesicles.

In the 1-inch Geological Survey map the igneous masses at the
northern and southern ends of the section are connected by a strip
of igneous rocks running along the north-western boundary of the
inlier. No trace of this is to be seen now, that part of the country
being drift-covered, though round the Pigeon House are several
exposures of ashy shales and calcareous ash." |

VY. Tae Livesrone SERIES.

(a) The Coast-section North of the Grits.

The limestone series is exposed along the coast from the northern

«

martello tower on the north to Priest’s Chamber on the south, a .

distance of about 3 mile in a straight line, though if the indenta-
tions of the coast be followed the distance would be far greater.
Owing to the evormous amount of faulting and folding to which
the beds have been subjected, it is impossible to ascertain their
thickness with accuracy, but the general succession from above
downward is :—
3. Thin-bedded limestone with shaly partings.
2. Beds of compact, grey, crystalline limestone with many fossils.
1. Thin-bedded limestones with shaly partings, the upper beds being
in places crowded with corals, while the lower beds become more
shaly. /

The beds may best be described by following the coast-exposure in
some detail, and understood by referring to the section (Pl. XLII).

The most northerly exposures are two knolls of black fissile shales
which project into the sandy bay south of the northern martello
tower. They are considerably crushed and contorted, but have
yielded obscure traces of graptolites, are probably bounded by faults
on either side, and are succeeded on the southern boundary of the
bay by brown shales with thin limestone-bands. These beds are very
much faulted, crushed, and folded (see fig. 2, p. 528), and every stage
can be traced between a continuous limestone-band and one which
has been broken up into small rounded fragments, so as to present
precisely the appearance of a conglomerate. ‘To this type of rock
we propose to restrict the term ‘ crush-conglomerate, applying the
term ‘thrust-conglomerate’ to a conglomerate formed along a
thrust-plane.

In spite of the disturbance to which these beds have been sub-
jected, remains of fossils (crinoids and corals) can be detected in the
limestone.

Before long the shales become less plentiful, and the series passes
up into a fairly compact band of limestone, perhaps 30 feet thick,
and haying an easterly dip. This bed forms the coast till close to

‘ Ina small excavation in the railway-cutting immediately south of Donabate

Station, about 2 miles to the west, we saw an exposure of a very coarsely
porphyritic rock with a green groundmass and large white porphyritic felspars.

Fig. 1.—Overfolded Bala Limestone and Shale. (Close to
the spot marked C in the map, Pl. XLIII.)

[From a photograph by Mr. 8. H. Reynolds. |

Fig. 2.—Limestone-and-shale bands, beginning to be broken up by
pressure, in the bay south of the northern martello tower.

[From a photograph by Mr. H. Preston. ]

ee a ee

Vol. .53.] THE PORTRAINE INLIER (CO. DUBLIN). 529

the end of the point south of the Old Limekiln. Here thin-bedded
limestones with shaly partings ceme on again below the compacter
bed, and, as might be expected, the signs of disturbance become
more marked, the thin bands of limestone being often crushed so as
to form what look like bands of nodules or pebbles embedded in
shale, while excellent examples of overfolding may be seen (see
fig. 1). At the head of the bay, south-west of the Limekiln, the
limestone is traversed by two or more faults and shows signs of
much disturbance; but at the western end of this bay the beds
are undisturbed, and consist of thin regular bands of limestone
alternating with shales.

Resting upon these limestones and shales we again find the
compact limestone, which is here very hard and forms a prominent
rampart-like mass at the top of the cliff. This bed and the under-
lying shaly limestone occupy the coast as far as the next point, and
it is along here that the limestone has proved most fossiliferous. A
small quarry has been opened at the top of the cliff in the compact
limestone, at the spot marked C in the map (Pl. XLIII), and from
it we obtained the fossils enumerated in the Appendix (p. 535).
Ofthese, Cherrurus bimucronatus, Pseudospherexochus subquadratus,
Spherexochus mirus, Cybele rugosa, Trinucleus seticornis, and Stauro-
cephalus are worth mentioning here. A portion of this limestone
was dissolved in acid, and 4°3 per cent. of it was insoluble: this
residue, when examined under the microscope, being seen to consist

- chiefly of small pieces of pumice and a little pyrites.

The limestones interbedded with shales are at this spot exowded
with corals, excellent specimens of which, weathered out by the
sea, were readily procured. Halysites catenularia and Heliolites
megastoma were the most numerous forms, and a complete list is given
in the Appendix. From the abundance of coral lite which existed
here one is justified in regarding this as a coral bank.

The next small bay is divided into two by a tongue of rock, through
the landward end of which the sea has forced a passage. The signs
of disturbance here are very great indeed. The more northerly
of the two little bays shows interbedded shale- and limestone-bands,
all much crushed, the rock showing an excellent overfold at one
place. The Point is also formed of these much-crushed limestones,
the bands being so much broken and the resulting fragments so
much rounded as to forma crush-conglomerate, this being especially
well seen below high-water mark on the south-western side of the
tongue of land mentioned above.

Here, too, a compact grey limestone is seen underlying the shaly
limestone, but it did not prove fossiliferous.

The more southerly of the two portions of the small bay is cut
into much disturbed beds of limestone and shale, but at its south-
western boundary the compact limestone again comes on, being
separated from the limestone and shale by a wedge-shaped mass of
a conglomerate formed of limestone-pebbles, all much rounded, in
a calcareous matrix—obviously a conglomerate due to earth-move-~
ments,

Gov. Ges. No. 212. 2N

630 MESSRS. C. I, GARDINER AND S. H. REYNOLDS on | Dec. 1897,

Greatly disturbed limestone, with a mass of shale faulted in,
occupies the coast by the next little inlet up to the succeeding point ;
but there we again come upon compact limestone which occupies the
next projecting part of the coast; and finally, as one reaches the
little bay known as Priest’s Chamber, the compact limestone is over-
lain by bedded limestones with shaly partings, and this becomes
more and more disturbed, passing into a thrust-conglomerate which,
as we mentioned before, occurs here at the junction of the limestone
with the grit series.

(0) The Coast-section South of the Grits.

Limestone-beds are exposed along a strip of coast, some 250 yards
long, south of the grits in the sandy bay near St. Kenny’s Well.
They are not nearly so calcareous as the beds just described, but are
of the nature of soft argillaceous limestones. It is due to this fact,
no doubt, that they have been so much denuded away, and that
they are now only exposed in isolated patches projecting through
the sand.

The lowest beds are exposed at low tide at aspot about 150 yards
S.S.E. from the Gamekeeper’s Lodge. They consist of calcareous
shales, and rest on igneous rocks. The latter show signs of much
crushing, while the former are cracked and veined with quartz, and
this renders it probable that the junction is a faulted one. Other
exposures of the rock occur, and it appears to pass up into a black
limestone with shaly partings: this becomes nodular in its upper
parts, and is separated from the grit series by a thrust-conglomerate,
as is the case with the limestones of Priests Chamber. The dip of
these limestones is about 30° 8.E. No fossils were found in them.

(c) Exposures Inland.

South-west of the northern martello tower are several exposures
of calcareous rocks, most of them close to the Pigeon House and
the Tower which have been built in the Deer Park. Though lime-
stone-bands interbedded with shales occur, the majority of the
exposures are in calcareous or shaly ashes.

Some of these ashy limestones contain perfectly-rounded pebbles
of compact andesites, ight green in colour. South-west of the
Pigeon House occurs a fossiliferous limestone with included frag-
ments, resting on a calcareous ash which overlies a calcareous
conglomerate containing corals; all these beds dip at a high angle
(? 60°) to 10° south of east. A calcareous conglomerate also occurs
near the Tower itself, and under it are limestones with shaly partings
and ash-bands, dipping at about 45° S.E.

The Pigeon House is built on coarse ashes, but nodular and shaly
limestones occur here also. The fossils which were found in these
calcareous beds indicate that their age is the same as that of the
limestones of the shore, and there can be no doubt that we are
dealing here with lower beds of the same series, :

Vol. 53.] THE PORTRAINE INLIER (CO. DUBLIN). | 531

VI. Tue Grir SERIEs.

Between Priest’s Chamber and St. Kenny’s Well, a distance of
about 600 yards, the coast is formed of green and brown grits and
slates, which dip, on the whole, E. 20°8., but roll slightly. The
coast-line in the main follows the strike, and only about 220 feet
is seen. There is a marked discordance, as observed by the
officers of the Geological Survey, between the dip of the series and
the dip of the cleavage of the interbedded slate-bands. These
beds yielded no fossils, and are separated by a mass of thrust-
conglomerate from the underlying limestone series, so that we have
no direct evidence of their age, but their resemblance to the grits
and slates which occur near Balbriggan, some 8 miles to the
north, is worth noting. These latter beds contain bands of black
slate yielding Monograptus Becki, M. triangulatus, M. Hisingert,
M. gaculum, Diplograptus tamariscus, and Petalograptus palmeus,
and apparently therefore belong to the Middle er Lower Birkhill
Series.?

Two smajl exposures of grit occur a short distance inland, and

the spring at St. Kenny’s Well is probably thrown out at the base
of the series.

VII. Tuer ConclomEeraArEs DUE TO EARTH-MOVEMENTS.

The strip of coast which we are describing has been subjected te
so much disturbance that conglomerate-like rocks produced by earth-
movements occur almost wherever the lithological character of the
beds admits of their being formed.

These beds, as already noted (p. 527), we divide into two classes:
(a) crush-conglomerates and (6) thrust-conglomerates.

The crush-conglomerates, in this area, are those formed by the
separation of a bed of limestone into parts, the parts having been
subsequently rounded.. All stages in the formation of such beds
may be traced. Compact bands of limestone may be seen, at first
cracked, but not displaced; then, a short distance farther along,
the cracks become more obvious ; and at length the portions of what
must have been a continuous band have become separated one from
another by a gap, now filled with the shaly material derived from
the shale-bands above and below. »

It is very clearly seen on the south side of the bay, just south of
the northern martello tower, that where the bands of limestone
differ in thickness the wider bands, here about 10 inches thick, have
merely been cracked, their portions having suffered no displacement ;
while the intermediate bands have not only been fractured, but their
fragments have undergone a certain amount of displacement ;
and the narrower bands, here some 2 or 3 inches thick, have been
cracked, and their fragments are now separated by several inches
of shale. These fragments are now thoroughly rounded, and pre-

1 These graptolites have been determined for us by Miss E. M. R. Wood and
Miss G. L. Elles.

252

532 MESSRS, C. I. GARDINER AND 8. H. REYNOLDS on [ Dec. 1897,

sent the exact appearance of limestone-pebbles embedded in shale ;
and were it not for the gradation, visible at so many points, between
the uncracked limestone and these beds of limestone-pebbles, the
origin of the latter would be hard to prove.

The shale-bands intervening between the limestone-bands also
show signs of disturbance—cracks, now filled with infiltrated mate-
rial, being numerous. This, too, is evidence of the agent which has
probably brought about the present rounded form of the originally
angular fragments of the limestone-bands. There can hardly have
been sufficient friction between the limestone-fragments and ° the

Fig. 3.—Thrust-conglomerate at Priest’s Chamber.

[From a photograph by Mr. H. Preston. }

shale to bring about the rounded appearance of the latter, and it is
to the dissolving agency of infiltrating water that one must look to
explain the rounded appearance of the fragments. This type of
conglomerate due to earth-movements may be seen frequently along
the coast ; but the other type, namely, the thrust-conglomerate, is to
be seen only at the places where the thrust-plane between the grit
series and the limestone series is visible, that is, at Priest’s Chamber
and near St. Kenny’s Well.

The Point north-east of Priest’s Chamber consists of compact
limestone overlain by bands of limestone and shale, these bands
being about 6 inches thick. They pass both laterally and vertically
into shale interbedded with bands of rounded blocks of limestone,

Vol *5 3. | THE PORTRAINE INLIER (C), DUBLIN). 533

and as Priest's Chamber is reached the rock becomes a thrust-
conglomerate formed of well-rounded blocks of limestone and cal-
careous ash varying greatly in size, embedded in a matrix formed of
fragments of the same material and of crushed shale (see fig. 3).
Some of the blocks of ashy limestone contain uncrushed corals and
brachiopoda, and sections from these blocks show under the micro-
scope no straining or evidence of crushing.

Over this conglomerate lie the grits with much-crushed black
slates at their base (see fig. 4).

Fig. 4.—Diagram of the cliff at Priest’s Chamber, looking

north-west.

Crushea = ee ‘ — 3 Se
Wehen Foe vas fe
shale 7 -< re ay a fA a2 eee ee CSS

DP es EY Ys Se. aT <a a SS
nna) Poff PARSE
conglomerate” ey by ee EEN SX Sl

nO Ses TSO IS shale-bands

It isan interesting fact that, both at this point and at others where
the disturbance has obviously been very great, sections of the matrix,
as well as sections from the included blocks, show very little sign of
it. At Priest's Chamber the matrix is seen under the microscope
to resemble, on the whole, the ashy limestone exposed inland in the
neighbourhood of the Pigeon House, though traces of crushing are
to be seen, and sericite is occasionally developed.

On the shore south of St. Kenny’s Well there is a larger exposure
of thrust-conglomerate, but no cliff-section. The uppermost beds of
the limestone series consist here of calcareous shales passing up
into a black limestone with shaly partings. The upper bands
become nodular, and the series dips S.E. at about 30°. Above
comes a bed chiefly composed of limestone-blocks sometimes a foot
or more in length, and usually rounded and arranged in layers, the
limestone of the blocks being similar to that of the underlying
beds.

The matrix in which these blocks are embedded is sometimes an
ordinary black shale, showing evidence of having been much crushed,
and forming patches quite discontinuous one from another; but
more often it is a crushed limestone or a crushed calcareous ash,
sometimes containing much pyrites. We estimated the thickness

534 MESSRS. C. I. GARDINER AND 8. H. REYNOLDS on [ Dec. 1897,

of this bed to be about 30 feet; it is sometimes overlain by a bed
of a finer character, which, though it is to a considerable extent
calcareous, contains no large limestone-pebbles, and.is mainly made
up of small fragments of lava and grit. Above this bed come the
unaltered grits.

This thrust-conglomerate has obviously been formed by the
thrusting of the grits over the limestone series; and the bulk of it has
been derived from the latter, the tough grits not lending themselves
readily to its production. The limestone before the disturbance
must in some places have been of an ashy type, and in others have
had shaly partings.

VIII. Summary anp Conc.usions.

In spite of the break between the limestone and the igneous series,
there seems to be sufficient evidence to prove the general succession
of the rocks.

The igneous series, of which the lowest beds seen are of the
nature of lava-flows, is overlain by a coarse ashy conglomerate,
some of the blocks in which were derived from a neighbouring
limestone, while others were derived from lava-flows and ash-beds.
This bed becomes finer in texture as it is traced upward, and
passes up into finely calcareous ash-beds with intervening bands
of ashy limestone and shale, which have yielded fossils bearing a
Middle Bala facies. One of the highest, beds of the series is a bed
of earthy shale which has yielded fossils, all of which occur in the
Middle Bala of Great Britain.

The limestone series has at its base many small bands of shale,
and when the thick bands of limestone come on they are seen to be
of a distinctly ashy type. The coral-bed in the series is shown by its
fossils to be, in all probability, of Middle Bala age, and is covered
immediately by the compact crystalline limestone, which, as noted
in the Appendix (p. 538), is closely comparable to the Sholeshook
Limestone of South Wales, and is mentioned by Mr. Cowper Reed
as being very probably of Upper Bala age.

The succession, though broken, appears therefore to be obvious,
the break having occurred in the ashy-calcareous rocks intervening”
between the ashy conglomerate and the limestone-beds, but how
much of the ashy-calcareous rocks has disappeared there 1s po means
of telling. There is also no evidence as to the former relation in
time or in space of the grits between Priest’s Chamber and St. Kenny’s
Well to either of the other two series.

The Portraine Limestone, though it has yielded no new species, is
an important rock, and is comparable to the Chair of Kildare Lime-
stone on the one hand, and on the other to the Stawrocephalus.,
Keisley, and Sholeshook Limestones of Great Britain.

The igneous rocks, in spite of their being much altered, show,
though not so well as do those of Lambay Island, that there was an
active vent in this neighbourhood—apparently in Middle Bala times.
Where the exact situation of this vent. was we have no evidence at

Quart. Journ. Geol. Soc. Vol, LIII. Pl. XLII

RAINE (Co. Dusuin),

ST.KENNY’S WELL
i]

ZZ Lila 2 ;
x
as

: ‘ ; H
Calcareous slates “=* Grits and Slates
dipping at 45 E.5 &,

‘ Lime KILN .E,
‘
‘
~ al ey y /
SAMMI, Se Td |e
2 at - :
ee a isivit Whar % = OPO PO ee
b TTT TOES 5 =

Lorman sy
UTES SP,

ae Dy
Rx sm, 2 y
Sen SOM We rps Ve, a SS = '
‘ € i
F \ FOURS \ / Fi

Set ee Je
Compact limestone ee ahnd ise compact Crushed Slate

Ww

=~ - * eas 2. L
2 of coarse porphyrite Andesites‘dipping S.E. “dipping cang
a °

nile. ]

re

moe
Ww
iat

\ Quart. Journ. Geol. Soc. Vol, LIII. Pl, XLII

SrcTION ALONG THE cos, Porrraine (Co. Dusuin),

S.W.
N.E,

S.MARTELLO ToweR
| ST.KENNY'S WELL
\

TANS” >
BNI DOI ONENESS

u i “| S i
Crushéd green Coarse porphyrite Andesites ! 1 $2; '
i Ful Caleareotis slates Grits and Slates
CHEERIER general dip S.E. Slate dinning dipping at 45 E.6 8,
at 50°E.10°N
- DEER PARR Priests eae
} ase 1 \ Lime KILN N.E,

: | p
{ ZB. An
\\ Tere
NW TAS
d eA To SON ky PUL ss
f FEW SS .
l ray yi
Grits and Slates Thrust congl Compact imestone Compact limestone Orushed Let: copa Crushed Slate
~ N. E. w

‘sc — =
AUST TINO KDE
MD 025% y

TAN 2

OSs d
yy Asby Coarse ashy conglomerate | Dyke of coarse porphyrite Andesites‘dipping 8.E. Foreman congl.
withLst.bands Lst.band with Coarse rng as

: Lst.bahd with underlying shale porphyrite

overlying shale

CG, ushed Slate Limestone conglomerate
[Scale: 12 inches=1 mile.]

Quart. Journ. Geol. Soc. Vol. LITI. Pl. XLII,

Coarse porphyri te
Dyke /|

gre ft
he Be
Re he is AES am
at AT AS Th gerne Tr es
anita AWK
S

|

a of. limestone overlaid by
© with obscure. graptolites
j ste

a ee mens N.MARTELLO TOWER

-- Thin bands of limestone interbedded

pay a Ki i en with ash,all much disturbed
| ; EE ee "a /Andesite

rie, 3 a”: OAT

, Overfolds : See ialf ae -Trilobite-shale

in limestone?~

ear Limestone series very greatly disturbed

epess---Dark compact limestone with many fossils (C)
“Corals plentiful

NAY cS Thrust-conglomerate,
SS SS ~---=--grits thrust over greatly-disturbed
Roan bedded limestone

GEOLOGICAL SKETCH -~MAP

OF THE PORTRAINE INLIER
(Co. DUBLIN)

Scale: 4 inches =r mile.
—————————————————

aults, ]

Quart. Journ. Geol. Soc. Vol. LIT. Pl. XLII,

%,Co4ST GUARD Coarse porphyrite
STATION POD
Green & purple an
°
360 A 1

S,E.dip.
imestone with underlying shale

~Band of.limestone overlaid by ie
shale with obscure. graptolites 2).--Andesite

+ ( -—="-N,MARTELLO TOWER,
\(B)._ 4A)
A " Black shalec Thin bands of limestone interbedded
ai ee ef shy limestones _with ash, all much disturbed
DEER PARK : i
a, Hey ‘s A ® f
y i Ouerfolds ‘==----7) -shal
| 8 : cs Eo: i Quertot i riloblte-shale
y i

ASF

eee,

&
Por;
ert

Ef woe Limestone series very greatly disturbed

--Dark compact limestone with many fossils(C)
orals plentiful

Thrust-conglomerate,
~-=--—-grits thrust over greatly-disturbed
bedded limestone

Gt
SiKenhys

Thntoh Chapel Sy
Coarse conglomerate. EX
porphyrite uF a \

Tt Ri

“ts GAMEKEEPER'S aac}
Argillaceou
limestone

1 yfaeaeaie
shal
\ ale,
GEOLOGICAL SKETCH-MAP

OF THE PORTRAINE INLIBR
(Co. DUBLIN)

iP Andesites much orushed Scale: 4 inches =r mile.
is and altered SSS

S.MantéL.o Tower

(F F = Faults]

fad

=

Woll, 53. | THE PORTRAINE INLIER (CO. DUBLIN). 530

Portraine to show, but the coarse breccias and tuffs of Lambay
Island seem to indicate that one of the centres of vulcanicity lay to
the east.

While the interest attaching to these Bala beds and to their
relation to English and Welsh rocks is great, the importance of
the area as a whole is enhanced by the presence of rocks of a
conglomeratic nature formed at a later date.

In a paper read before this Society in 1895 by Messrs. Lamplugh
& Watts attention was drawn to crush-conglomerates in the Isle of
Man, and there seem to be many points of resemblance between the
Portraine and the Isle of Man conglomerates. In both cases hard
beds which occur among beds of shale have been cracked, pulled
asunder, and converted into a conglomeratic deposit; in the one
case these hard beds are formed of limestone, and in the other of
sandstone. In both cases, too, shearing has taken place, and along
the thrust-planes conglomerates have been developed. But the
amount of actual deformation of the broken pieces of the hard beds
at Portraine seems to have been quite trifling when compared with
that which has occurred in the Isle of Man, and this appears to be a
very important point. The amount of mineralogical reconstruction
seems also very small. Either the nature of the beds at Portraine
did not readily lend itself to alteration, or the time occupied in the
formation of the conglomerate was long; and thus the heat en-
gendered had time to be conducted away before the rocks had arrived
at a sufficiently high temperature for mineralogical alteration. The
occasional occurrence of sericite is the only evidence of mineralogical
reconstruction due to the crushing.

In conclusion, we wish to express our sincere thanks to Mr. F.
R. Cowper Reed, F.G.S., for his assistance in the identification of our
fossils and for writing the Appendix to this paper. At the same
time we would thank Miss Elles and Miss Wood for having identified
our graptolites; Mr. Alfred Harker, F.G.S., for looking over some of
our rock-sections; Mr. W. W. Watts, F.G.S., for having assisted us
in many ways; and Mr. H. Preston, F.G.S., for having allowed
us to make use of his photographs of the coast. We also gratefully
acknowledge the kindness of the authorities of the Irish Geological
Survey in giving us eyery facility for examining their collection of
fossils.

AppenDIx. By F. R. Cowper Resp, Esq., M.A., F.G.S.
(a) Fossils from the Limestone at point C in the Map.

Tritopira.—The fauna of this limestone consists principally of
trilobites, which both in species and individuals form the majority
of the fossils. The following is the list of the trilobites, but the
extremely fragmentary condition of most of the specimens rendered
their identification a matter of much difficulty :—

536 MR. F. R. COWPER REED ON THE FOSSILS OF [ Dec. 1897,

Calymene Blumenbachi, Brongn. Ilienus Bowmani, sp. B.
Cheirurus bimucronatus ¢, Murch. , ef. oblongatus, Ang.
juvenis, Salt. (? clavifrons, Dalm.).| Lichas sp.

[ Pseudospherexochus| subquadra-| Remopleurides sp.

tus, Reed. Spherexochus mirus, Beyr.
Cybele rugosa, Portl., var. a. Staurocephalus sp.
, var. attenuata nov. Stygina latifrons, Portl.
Har pes, 2 spp. Trinucleus seticornis, His.
Ilienus Bowmani, Salt. , var,
— , SP. @.

Of the above the J/lenz are the most abundant. Besides J. Bow-
mani there are fragments of a form (sp. a) possessing an ornamen-
tation of small pits distributed with some regularity over the shell,
with a very finely-punctated surface. But the specimens are too
imperfect to determine the species.

Another form has the general appearance of J. Bowmani, so far
as the fragments allow one to distinguish its characters, but the
pygidium is seen to be bluntly pointed behind when the shell is
removed and the cast of the under surface displayed to view.

The remaining form, represented by one imperfect pygidium in
this collection, has thé shape and prominent axis of J. oblongatus
(Angelin), with which it may be compared; but it is not quite
clear whether the specimen has not suffered crushing and distortion.

Calymene Blumenbachi and Spherexochus mirus are represented
by several pygidia and head-shields which call for no remarks.

Trinucleus seticornis of the typical Swedish form, without the long
head-spines of 7’. Bucklandi, occurs in the limestone, so far as one ~
can Judge from portions of the fringe and general expansions. But
in one specimen the three or four uppermost rows of pits on the
convex portion of the fringe immediately in front of the glabella are
situated in regularly radiating grooves, giving a very distinctive
appearance to this part. In other respects the specimen resembles
the typical 7’. seticornis, and can only be considered a variety of it.

Cybele rugosa appears to occur, for I can only regard the two
imperfect pygidia of a Cybele as belonging to this species. In
‘variety a’ three pairs of small tubercles are situated on the axis,
just at the inner termination of the incomplete transverse furrows
which mark out the rings on the axis. This specimen closely
resembles that figured by Nicholson & Etheridge in their ‘ Mono-
graph of the Girvan Silurian Fossils’ (pl. xiv. fig. 13); while var.
attenuata has the long attenuated axis of M‘Coy’s figure (‘ Syn. Brit.
Pal. Foss.’ pl. i.e, fig. 8), but there are three pairs of small tubercles
on the axis as in the other variety, and the ribs on the lateral lobes
are narrower, except the outer one, which is flattened and pitted so
as to give a somewhat wide margin to the upper part of the outer
edge of the pygidium. Otherwise it is similar to M‘Ooy’s figure.
It may be designated as var. attenuata. Fragments of the head-
shields of Cybele are abundant.

Har pes 1s represented by two fragments belonging to the punc-
tated border of two species. The punctures in one specimen are
much coarser and more irregular than in the other, which is uni-
formly covered with fine minute pits.

iol. 53. | THE PORTRAINE INLIER (CO. DUBLIN). 537

Of Remopleurides I have been able to identify only one portion of a
free cheek and eye, of which the species is doubtful.

The species of Cheirurus are badly preserved, with the exception
of Ch. [ Pseudosphereaochus | subquadratus, one excellent specimen of
which I have discovered.

Staurocephalus appears rare, but I have chipped out one specimen
of the globate portion of the glabella. Whether it belongs to
St. Murchisoni or St. globiceps is doubtful.

Stygina latfrons is represented by one pygidium.

ENTOMOSTRACA.

Primitia M‘Coyi, Salter, occurs sparingly in this limestone.

BRACHIOPODA.

The following brachiopoda have been identified among the
specimens handed to me. There are fragments of some others
which, however, are much too imperfect for identification. But
brachiopoda on the whole seem to be far from common; Orthis
biforata, Plectambonites sericea, and Rafinesquina deltoidea, var.
undata, are the most abundant species.

Orthis biforata, Schloth. Rafinesquina deltoidea, Conr.
elegantula, Dalm. ? , var. undata, M‘Coy.
testudinaria, Dalm. Strophomena, sp. ?

var Triplesia insularis, Kichw.

, var.
Plectambonites sericea, Sow.

Mortivsca.
Bellerophon sp. Modiolopsis sp.
Cyclonema sp. Orthoceras audax, Salter.

The only shell of which I am able to identify the species is
Orthoceras audax, which is found at Rhiwlas, and probably at the
Chair of Kildare.

Potyzoa. Ptilodictya lanceolata, Goldf.

Actinozoa. Helioltes sp. and Halysites sp.

This species of Heliolites resembles, in the paucity of coenenchymal
tissue, etc., the description and figures of Palwopora { Lyopora | favosa,
M‘Coy, in M‘Coy’s ‘Synopsis of British Paleozoic Fossils’ (pl. i.c,
fig. 3, p. 15), but Nicholson & Etheridge have declared M‘Coy’s
account to be apocryphal. The larger corallites are, moreover,
smaller and closer together than in typical specimens of L. fuvosa
from Scotland.

Conciuston.—The fauna of this limestone has undoubtedly a Bala
facies, but judging from the presence of Stygina latifrons, Pseulo-
spherexochus subquadratus, T'rinucleus seticornis, Cybele rugosa, and
species of femopleurides, Harpes, Staurocephalus, and Primitia
M‘Coyi, I should be inclined to associate it more closely with the

038 MR. F. R. COWPER REED ON THE Fossits oF [ Dec. 1897,

Staurocephalus-, Chair of Kildare, and Keisley Limestones, and espe-
cially with the Sholeshook Limestone of South Wales, than with the
typical Middle Bala. So that, on the whole, its horizon may be with
much probability considered to le near the base of the Upper Bala.

(6) Fossils from the Limestone-bands immediately beneath
the Compact Limestone from which the preceding were
obtained.

The whole fauna appears to consist of corals, most of which are
in an inferior state of preservation.

Favosites aspera, @ Orb. Lindstremia sp.
Halysites cf. escharoides, Lam. Stenopora fibrosa, Goldf.
catenularia, Linn. Streptelasma europewm, Rom. ?
Heliolites megastoma, M‘Coy. SS SDD
sp Cybele sp.

Lindstreemia subduplicata, M‘Coy.
The Middle Bala facies is obvious.

(c) Fossils from the Grey Shales marked in the Map as
Trilobite-Shales.

These fossils are poorly preserved. By far the most abundant
form is Trinucleus seticornis, var. portramensis.

TRILOBITA.
Agnostus agnostiformis, M‘Coy Cybele sp. ?
(=trinodus, Salt.). Tichas laxatus, M‘Coy.
Ampyx sp. : Phacops Brongniarti, Portl.
Asaphus radiatus, Salt. ? Trinucleus seticornis, var. portraimensis
Cheirurus juvenis, Salt. ? nov.

Bracuiopopa. Orthis sp.

Moxiusca. Hyolithus sp.

EcuinopERMATa. G'lyptocystites, cf. Logant, Billings.

The general facies of the fauna appears to indicate a lower
horizon than the limestone at the spot marked C. None of the
species are characteristic Upper Bala forms, and nearly all occur in
the Middle Bala of Great Britain.

TRINUCLEUS SETICORNIS, His., var. PORTRAINENSIS nov.

Head-shield as in the type-form of Hisinger’s species, with the
exception of the hmb. Genal angles of limb flattened out, and not
produced backward behind the head, as in the type-form. Limb
divided in front into two parts by an encircling striated groove, but
not so markedly as in the type-form.

On the inner portion of the flattened expansions of the limb at the

:

Vol. 53.! THE PORTRAINE INLIER (CO. DUBLIN). 539

genal angles, the pits are arranged as in the type-form, but the pits
in the two outer concentric rows lie in short, regular, radiating
grooves with intervening ridges, thus resembling 7. fimbriatus, but
differing therein that the grooves do not extend to the edge of the
limb.

In front of the glabella the pits of the three outer rows lie in
these radiating grooves, but behind them, and also on the upturned
portion of the limb, lie one or two independent rows of pits not in
grooves. In front of the glabella and cheeks the inner convex portion
of the limb also has three or four concentric rows of pits arranged in
similar radiating grooves, as in tbe variety of T’r. seticornis from the
limestone at the spot marked C.

EXPLANATION OF PLATES XLII & XLIII.
Pratt XLII.

Section along the coast, Portraine (Co. Dublin), on the scale of
12 inches to | mile.

Pirate XLITI.

Geological Map of the Portraine Inlier on the scale of 4 inches to | mile.

Discussion.

Mr. LampiucH was, in the main, able from personal observation,
under the guidance of Mr. McHenry, to corroborate the Authors as
to the effect of earth-movement in these sections. The readiness of
the thin-bedded limestones to break up into crush-conglomerate was
striking. In areas affected by shearing, he thought that the origin
of every conglomerate should be carefully investigated, and was glad
to find that this was the attitude of the Authors. Though the lower
ashy conglomerate might have been an originally fragmental deposit,
he thought that it had undergone some subsequent modification.
To distinguish between the original and the superimposed structure
in such cases was, as he knew by experience, difficult. He doubted
whether the distinction drawn by the Authors between crush-
conglomerate and thrust-conglomerate could be generally main-
tained.

Mr. W. W. Warts also spoke, and Mr. C. I. Garpinzr replied.

540 DR. W. FRASER HUME ON [ Dec. 1397,

36. The Cretaceous Strata of County Antrim. By Dr. W. Fraser
Home, F.G.S. (Read June 9th, 1897.)

[Puates XLIV & XLV.]

ConTENTS.
Page
I: Introductory and Descriptive ..)..4cccusis.acs vescenes dees age 540
(1) ‘Dhe Souther Division | ..74.je3s: cies sone eee 545
(2)."The Central Division 5:4 5...<cn<0.o6 0609-02 eee 548
(S) The Hastetn Division © .ch1..5e28heeeneds ose eee 554
(4) The Peninsular or Insular Division .................. 565
(5) The Northern Wiviston \.c.cc6.c0ccccus<csan8e aoe eee 567
Il. Chemical and Micromineralogical Sections .................. 568
IIT. Conclusions as to the Sequence and Correlaticn of the
Inish Cretaceous! Strattar ...2202 .cccna cee. cds cane acevte nacheeeee 585
LV. ‘General Considerations: <1.20 Poot ccc sats veenne.cned meee 599
BEY SUT EAS eA ee | Rea kee A na facing 568
AD aOLG UT peck etacencass toc econ eeeeeag x: oroacs oot aaee » 084
OP DOIG AMM (= yc toc 53 pe cececa saat age whore ae eae cae » 984
DEIN Rah ee ce ae) Ra a eR Dr » 098

I. Inrropuctrory AND DESCRIPTIVE.

AurnoucH, during the last twenty years, the Upper Cretaceous
strata of England and the Continent have been the objects of detailed
investigation, the deposits of the same age, which form so con-
spicuous a feature in the North-east of Ireland, have been practically
neglected. Two observers only, Prof. R. Tate’ and Dr. C. Barrois,’
have seriously attempted to classify these formations on definite
paleontological principles, but the results at which they respectively
arrived differ in several material particulars. The present paper is
the outcome of two excursions carried out in the summers of 1895
and 1896: the first connected with, and following on, the Geologists’
Association’s visit to County Antrim, under the guidance of Mr. A.
McHenry ; the second aiming at a more detailed examination of the
stratigraphy of the same district. The first and second parts will be
devoted to the consideration of the various sections visited, together
with an account of the results obtained by applying the methods of
analysis and microscopical examination previously employed by me
in considering the Upper Cretaceous zones of the South of England.
In the third and fourth parts it is proposed to examine the theo-
retical questions arising out of these researches, dealing with the
zonal classification of the Irish Cretaceous strata, the probable
distribution of the land-masses, and the sequence of physical changes
‘during the period under consideration.

? Quart. Journ. Geol. Soe. vol. xxi. (1865) pp. 15-44 & pls. iii.—-y.
* ‘Recherches sur le Terrain Crétacé Supérieur de lAngleterre et de
VIrlande,’ Lille, 1876.

Vol. 53.] | THE CRETACEOUS STRATA OF COUNTY ANTRIM, 541

My thanks are due to the following members of the Belfast
Naturalists’ Field Club, who have freely placed their local know-
ledge and experience at my disposal :—Miss Sydney Thompson ;
Mr. A. McHenry, M.R.1.A.; Mr. 8. A. Stewart, F.L.8.; Mr. W.
Swanston, F.G.S.; Mr. J. St. J. Phillips; Mr. R. S. Bell; and
Mr. McLean. Messrs. A. Smith Woodward, F.G.S.; G. C. Crick,
F.G.S.'; A. J. Jukes-Browne, F.G.S.; R. B. Newton, F.G.S.;
Dr. J. W. Gregory, F.G.8.; Dr.G. J. Hinde, F.B.8.; /and Mr. F-.
Chapman, A.L.8., have also rendered valuable special assistance in
the examination and identification of the organic remains, the last-
named contributing a special report on the foraminiferal casts. Iam
also much indebted to Prof. J. W. Judd, C.B., F.R.S., for enabling
me to carry out my chemical and microscopical work in the Research
Laboratory of the Royal College of Science, and for having placed
the whole of his Irish collection at my disposal.’

It will not be necessary to recapitulate the results arrived at by
writers previous to the year 1865, as this has already been done by
Tate and Barrois in the works previously referred to. Tate was
the first to clearly recognize the lithological divisions of the Cre-
taceous system as they are developed in the neighbourhood of Belfast,
and seeing that these will be constantly referred to in the sequel, it
may be convenient to define them at once. They are in descending
order :—

White Limestone or Hard Chalk.

. Chloritic Chalk.

Chloritic Sands and Sandstones.,

. Grey Marls and Yellow Sandstones with Chert.
. Glauconitic Sands.

OUR 09 LD

The White Limestone is practically a hard white chalk, in
general containing well-marked layers of flint. .

The term ‘Chloritic Chalk’ has become so well established in
the literature of the subject that to attempt to alter it would tend
to confuse rather than to simplify the nomenclature. At the same
time, it must not be forgotten that the green grains in the rock
which were formerly believed to be chlorite would probably now
be classed with glauconite. Typically, Chloritic Chalk is a pink-
coloured limestone, having minute green grains of glauconite
scattered through it.

The ‘Chloritic’ Sands and Sandstones are among the most
variable members of the series, and are thus described by Tate (op.
cit. p. 23):—‘The beds between the Grey Marls and the White
Limestone are generally siliceous sands in a calcareous paste, and
contain disseminated chloritic grains. The compactness of this zone

' To Mr. Crick I am especially indebted for assistance in the examination
and identification of the cephalopoda mentioned in this paper, most of the
notes appended on this subject being the result of my conversations with him.

? For the beautiful photograph of the conglomerate at Murlough Bay I have
to express my hearty thanks to Mr. J. R. Welch, of Belfast.

542 DR. W. FRASER HUME ON [ Dec. 1897,

varies with the locality. On the whole, I find that, in ascending
the bed, it becomes more and more compact, by the predominance of
the calcareous paste, and the siliceous and chloritic elements become
less and less in amount, finally passing up insensibly into the con-
dition of a white compact limestone.’ Apart from the use of the
term ‘chloritic’ instead of ‘glauconitic,’ the above description
accurately states the character of this interesting set of beds.

The Yellow Sandstones are normally of a brown to yellow
colour, frequently containing well-marked bands of chert. Marly
layers may occur throughout, but are especially developed at the
base.

Finally, the Glauconitic Sands are of a deep green colour,
and in many localities mainly consist of glauconitic grains.

Tate further subdivided the lithological divisions into zones
which were named after the characteristic fossils. Thus the White
Limestone became the zone of Ammonites gollevillensis, while the
Chloritic Chalk included a Spongiarian zone and that of Ananchytes
gibbus, a band containing the latter species being taken as the base
of the Upper Chalk or Seaonian:

On the other hand, the Chloritic Sands (including the two zones
of Hxogyra columba and Inoceramus Cr rispt), the Yellow Sandstones
(zone of Ostrea carinata), and the Glauconitic Sands (zone of Kxogyra
conica) were all classed as members of the Cenomanian. ‘The general
conclusion, therefore, is that a paleontological hiatus must have
existed between the Chloritic Chalk and Chloritic Sands: the whole
of the Turonian, and a good part of the Senonian beds being un-
represented in the series.

Barrois re-examined the strata in the light of his researches on
the English Cretaceous zones, and came to the conclusion that the
Turonian, or Middle Chalk, was clearly represented in the Irish
district, certain bands, rich in Inoceramus-fragments, being especially
characterized by Turonian fossils. These, according to him, showed
the existence of the higher zones, namely, Holaster planus and Tere-
bratulina gracilis, that of Inoceramus labsatus being unrepresented.
He further believed all the Senonian divisions to be present, whereas
Tate placed the zone of Ananchytes gibbus on a level with that of
Belemnitella quadrata, in the Upper Senonian. The zones of
Ostrea carinata and Exogyra conica were referred by him to the
Cenomanian.

Neither of the two authors above mentioned have made any
reference to the remarkable conglomerates which form the base of
the White Chalk where the latter rests upon beds of more ancient
date, such as the Trias, Carboniferous, or metamorphic rocks of a
still older period (mica-schists, etc.). These beds were recognized
and carefully examined by Portlock.’ He also divided the Cretaceous

1 «Report on Geol. Londonderry, etc.,’ 1843. See especially pp. 115 & 749,
and generally pp. 90-140, where many references to the White Chalk and its
subjacent beds will be round.

Woleis:3: | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 543

into three subdivisions: (1) the Upper Chalk, (2) the Lower Chalk,
(3) the Arenaceous or Glauconous or Greensand; but under these
names are included beds, mainly of Senonian age, which differ
chiefly in their lithological characters. The officers of the Irish
Geological Survey have recorded these from many localities, as
at Slieve Gallion, in county Derry, and at Murlough Bay, near
Ballycastle.

In the Irish Survey Memoirs 7 & 8, by Symes, Egan, &
McHenry ; 12, by Nolan & Egan; 14, by Symes & McHenry; 18,
by Nolan & Egan; 20, by Symes; 21, 28, & 29, by Prof. E. Hull;
27, by Egan; and 36, by Hull, Warren, & Leonard, the litho-
logical characters of the rocks are discussed and the nature of their
distribution considered in some detail, but otherwise no important
information is added to that given in the previously quoted works.

In the Proceedings of the Belfast Naturalists’ Field Club,
1876-77, pp. 251-262, Mr. W. Gault, a local collector, expressed
his views on the Cretaceous beds of the district south of Belfast.
This paper, while arriving at conclusions with which, on many
points, the present writer finds himself in accordance, cannot be
trusted always, so far as the identification of fossils is concerned. The
association of Belemnitella mucronata, Actinocamax { Belemnitella |
plenus, Ammonites | Acanthoceras| rotomagensis, and Micraster spp.,
in the same beds may be cited as an example of the need of caution
in considering the bearings of the paper. The most important
points raised in it are the recognition—firstly, of the zone of
Exogyra columba as being of Upper Greensand age, and, secondly,
of the existence of an unconformity between the above and the
Inoceramus Crispi-zone.

The present state of our knowledge may be summarized in
tabular form, as shown on p. 044.

In the first part of the present paper a detailed description will
be given of the principal exposures of the Cretaceous in County
Antrim, most of which have been personally inspected. Much
obscurity has undoubtedly arisen, owing to the fact that previous
writers have laid but little stress on the local variations which form
a marked feature in connexion with these strata.

It appears to me that five divisions, in each of which the Cretaceous
rocks exhibit peculiar characters, are clearly marked out, and these
will be considered in turn. They are :—

1. A Southern Division, extending from Magheralin, 16 miles
south of Belfast, to the north of Lisburn.

2. A Central Division, continuing the above from Colin Moun-
tain, 5 miles south of Belfast, to a little north of that city.

3. An Eastern Division, including Islandmagee and all the
exposures from Larne to Cushendall. Woodburn Glen, near Carrick-
fergus, occupies an intermediate position between this and the
previous division.

4. North of Cushendall, and passing westward into Derry, is
a great series of ancient rocks, from pre-Devonian to Trias, which

~
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DR. W. FRASER HUME ON

544

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Vols 53:] THE CRETACEOUS STRATA OF COUNTY ANTRIM. 545

appears to have formed a prominent peninsula or island during the
major portion of the Cretaceous period. The Chalk strata connected
with this peninsular or insular region will be dealt with under the
Peninsular Division.

5. Finally, a Northern Division will include the Cretaceous
strata which are developed on the northern and north-eastern coast
of Co. Antrim, extending from west of Portrush to Ballycastle.

(1) Tue Sovrnern Division.

From Magheralin to Kilcorig.

The White Limestone is exposed in numerous quarries and may
be well studied at Magheralin, at Soldierstown, near Moira, and at
Kilcorig, near Brookmount. It consists of a compact hard chalk, in
which flattened flints are arranged in regular layers, generally
separated by intervals of 4 to 5 feet. At Soldierstown, in the
quarry situated farthest from the road, occurs a very fine example
of the ‘paramoudras’ of Buckland. At this locality five of these
barrel-shaped or pear-shaped potstones, about 18 inches in height
and a foot in diameter, form a vertical series, the lowest rising
from a bed of flint below, while the highest is cut off at the next
succeeding flint-layer. They are pierced from end to end by a
broad tubular canal, which has subsequently become filled with
calcareous sediment. It was in this district that Buckland first
met with these remarkable bodies, which Sollas regards as the
Cretaceous representatives of the recent sponge Poterion patera,
Hardwicke, and has consequently named them P. cretaceum.' The
skeleton appears to have consisted of pin-headed spicules.

A section of the limestone from Magheralin shows it to consist
of a calcareous paste, enclosing numerous examples of multilocular
foraminifera, among which Gilobigerina, Textularia, Bolivina, a
Marginuline form, and polyzoa may be recognized.

. The fauna of the Chalk in this district varies in but slight degree,
and is of a very general character, the principal species observed by
me being, in order of importance :—

Belemmnitella mueronata, Schloth.

Rhynchonella plicatilis, var. octoplicata, Sow.

Terebratula carnea, Sow.

Echinocorys scutatus, Leske.

Ostrea verticularis, Lam.

Cidaris (probably C. sceptrifera, Mant. \ in the lower part of the
Inoceramus (in fragments). limestone especially.
Polyzoa ; Onychocella sp.

The Flinty Flag of Kilcorig, 15 feet from the base of the Chalk,
which is described by Tate as a ‘highly splintery limestone,
irregularly crowded with flints, its upper surface covered with
branching sponge-remains embedded in a glauconitic paste,” is
unfortunately no longer visible, and in consequence we were not

1 Ann. & Mag. Nat. Hist. ser. 5, vol. vi. (1880) p. 441.

? Quart. Journ. Geol. Soc. vol. xxi. (1865) p. 26.
Q. 5: Go. Nor 212. 20

546 DR. W. FRASER HUME ON [ Dec. 1897,

able to collect any of the members of the interesting fauna which
he obtained from this locality. It may be useful to give a list of
the species described by Tate, with the addition of Ammonites
[ Pachydiscus| peramplus, which has not been previously recorded.
They are :—

CepHaLopopa: Ammonites [ Pachydiscus| peramplus (Mantell), P.
gollevillensis, d’Orb., Belemnitella mucronata, Schloth.

GastERopopa: Turritella unicarinata, Woodw., Cinulia catenata,
Tate.

Prtecypopa (Monomyaria): Ostrea vesicularis, Lam., Pecten ni-
tidus, Mant. ; (Dimyaria): Pholadomya cordata, Tate, and Ph.
Stewarts, Tate.

Bracutopopa: Terebratula carnea, Sow., Rhynchonella octoplicata,
Sow., and Megerlia | Kingena| lima, Defr.

EcuinorEa : Echinocorys vulgaris, Breyn.= LE. ovatus, Lam., type
and var. pyramidatus, Portl., Cardiaster ananchytis, Leske, G'alerites
abbreviatus, Lam., Cyphosoma corollare, Park.

Actinozoa: Farasmilia centralis, Mant.

PortFERA: Guettardia stellata, Mich.

Tate remarks: ‘from beyond Colin Glen, by Kilcorig, near
Lisburn, to Moira, it [the White Limestone] is seen resting
directly on the New Red Marls.’* This statement must be some-
what modified, the base of the Chalk being in reality a mulatto-
stone, that is, a greyish or pinkish limestone, in which are embedded
numerous very rounded grains of quartz, glauconitic casts of fora-
minifera, and green irregular masses. Often this rock becomes
conglomeratic, owing to the presence of large pebbles of quartz and
other detrital fragments. We have noticed this type at Magheralin
and Kailcorig, and it is recorded in the Geological Survey Memoir,
Expl. Sheet 36, from near Moira.

Of the mulatto-stone from Magheralin 14:16 grammes were dis-
solved in 20°/, hydrochloric acid, yielding 2°72 grs. of residue (this
excludes fine clay). The most numerous constituents of the insoluble
portion are extremely rounded grains of transparent quartz, having
an average diameter of ‘5 mm., flakes of silvery muscovite, and
green to yellow-green glauconitic casts of the internal chambers of
foraminifera, the original septation being in many cases still clearly
marked out.

In the quarry at Kilcorig lay blocks of mulatto-stone, containing
ramose bodies (often referred to under the vague terms Spongia,
Amorphospongia, etc.) and many pebbles, some of large size, one a
transparent specimen of quartz, being 2 inches in length and 1 in
breadth. Belemnitella mucronata was the only fossil observed.
Although the rock was not visible in place, we were told by
the foreman that it formed the floor of the quarry. The Chalk
appears to overlie directly the Keuper Marls, but a small rising
covered by grass hides the junction of the two rocks, so that the
conglomeratic limestone cannot be much more than a foot thick.
A microscopic section shows the calcareous part to consist of a cal-

1 Quart. Journ. Geol. Soc. vol. xxi. (1865) p. 25.

Wel! 53. ] THE CRETACEOUS STRATA OF COUNTY ANTRIM. 547

careous paste, in which organic remains are numerous. Small single
chambers of foraminifera, ‘(06 mm. in diameter, are the most
common, though unions of two, three, or more such are very frequent.
The only identifiable forms are several minute globulcse 7'extularie,
-2mm.in length. Nautiloid, rod-like, spiral, spindle- and dumbbell-
shaped sections are also abundant, the remaining organic constituents
being unidentifiable calcareous rods (‘75 mm. in length), sponge-
meshes, and fragments built up of hexagonal columns closely set
together. In addition to the above the Chalk contains angular
grains of quartz, some of which enclose apatite, and irregular green
patches of glauconite. A pebble of a glauconitie felspathic sand-
stone is also present, and round its borders the limestone has lost
all trace of the organic contents, becoming a fine-grained paste,
and at one point passing into crystalline calcite. Some flakes of
pyrites are visible in the latter constituent.

Near Maghaberry, 2 miles east of Soldierstown, greensand is
said to have been reached at the base of the quarry. It would
appear from all the cases that have come under my notice in this
district that this ‘greensand’ is in reality a ‘ mulatto-stone,’ the
true greensand, the ‘ Glauconitic Sands,’ appearing to be entirely
absent in these localities. At Balmer’s Glen, close to the above
village, beds rich in silicate of iron (probably glauconite) are said
to have a thickness of 5 feet.’ Similar beds are recorded from
Mullaghearton, as occurring between the Chalk and red Triassic
shales, and also south-east of Kilcorig, near Lisburn.

In this division the junction-beds between the basalt and the
Chalk are finely exhibited in several localities. At Kilcorig a
deposit of lignite and red flints underlies the basaltic mass ; while
at Soldierstown the entrance to the quarry previously mentioned is
cut through a dyke of considerable breadth. The Chalk on each
side has a bluish tint, while the flints are coloured various shades
of pink or red. The basalt itself, for a space of 2 feet from its
junction with the Chalk, is split into a number of thin layers running
parallel to the sides of the dyke.

The Southern Division is characterized :—

1. By the frequency of paramoudras. .

2. By the existence of a conglomeratic chalk at the base of the
white limestone, containing very large pebbles, which point to the
conclusion that the area from which they were derived could not
have been far distant. The presence of Belemnitella mucronata in
the rock leads one to infer that it was formed towards the close of
the Upper Cretaceous period.

N ote.—The officers of the Geological Survey have marked the
Upper Greensand as occurring along the line of outcrop throughout
the district. This arises from a misuse of the term Upper Greensand,
which in most of the Memoirs has been used for mulatto-stone
(even though the latter contained fossils of higher zones), as well
as for the underlying Cretaceous Beds, if present.”

1 Mem. Geol. Surv. Irel. Expl. Sheet 36, p. 32. 2 Ibid. p. 10.

202

548 DR. W. FRASER HUME ON [Dec. 1897,

(2) Tur Cenrrat Division.

From White Mountain to Cave Hill.

The first indication of a change in the character of the strata
underlying the White Chalk is a remark in the Geological Survey
Memoir, Expl. Sheet 36, p. 29: ‘ North of the cross-roads, 8.W. of
Castle Robin, a reddish sandy rock may be seen, containing fragments
of Inocerami: this is probably the upper portion of the Greensand ;’
and near Groganstown, still farther north, are ‘12 feet of greenish-
grey mulatto-stone, containing small pebbles of quartz in such
numbers that it might with propriety be termed a fine conglomerate.’

Colin Mountain.

On the sides of Colin Mountain, a large limestone-quarry is being
worked, to the south-west of which a small stream runs in a deep
groove, cut in the Cretaceous rocks. Here the lowest Cretaceous
beds, the Glauconitic Sands, are well exposed, a central band, 3 feet
thick, full of Ewogyra conica, var. levigata, Sow., being very con-
spicuous. Pecten [Janira] quinquecostatus, Sow., P. [Amusstum]
orbicularis (Mant.), and Avicula, near lineata, Rom., occur sparingly
in the band itself, but a little above it are more numerous. A
fragment of an ammonite, most probably Hoplites catillus, Sow.,
was also obtained. These beds pass into sands of a brownish-red
colour above, and into unfossiliferous deep-green sands below. Many
pebbles of small size are scattered throughout the series. The total
thickness of these strata is at least 12 feet, so that this locality
presents not only the most southerly, but also the best developed
exposure of these rocks, which, as we shall see later, are of Upper
Greensand age. They appear to correspond to the ‘glaucous marls’ of
Expl. Sheet 36, p. 28. A bridge crossing the stream, and a waterfall,
prevent a close examination of the Yellow Sandstone, which rests
upon the strata just described. ,

Higher up the stream, above the bridge, there are loose greenish-
yellow sands, which pass into a glauconitic sandstone, containing
unidentifiable sponge-remains. In the limestone-quarry itself, some
50 feet of White Chalk is exposed, containing Belemnitella mucro-
nata, Schloth., and Terebratula carnea, Sow., but otherwise presenting
no features of interest. Mr. Bell has obtained Yerebratula obesa,
Sow., and Ostrea vesicularis, Lam., at this locality.

Colin Glen.

The section in this glen, which is one of the most complete in
this part of the country, has been especially referred to by Prof. Tate.
Owing to repeated faulting, the Trias, Lias, and Cretaceous are
traversed several times in ascending the stream, so that the accuracy
of the succession can be carefully tested.

The red and green sandstones and marls of the Trias form the
base of the series at this locality. Above these follow the Rhetic

Vol. 53.] | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 549

beds, which here attain a considerable development, Avicula con-
torta, Portl., Cardium rheticum, Merian, and Pecten valoniensis,
Deir., being especially abundant in the shales. These <Avicula-
shales contain a bone-bed, which, from specimens in Mr. Swanston’s
collection, must be as clearly marked as those in the West of
England. Although we did not find the main band, teeth (probably
of Saurichthys apicalis, Ag.) and scales were present in considerable
abundance. The Liassic strata, which have been described in detail
by Tate,’ were not particularly examined, Ammonites [ Arvetites]
Johnston, Sow., alone haying been obtained.

The Glauconitic Sands, forming the base of the Cretaceous,
at once attract attention, und are at all times easily recognizable, by
their deep-green, almost blue-green colour, due to the large propor-
tion of glauconite-grains which they contain. The fossils in these
strata are numerous and well-preserved, including EHxogyra conica,
var. laevigata, Sow., Pecten[Amussium] orbicularis (Mant.), Cucullea
carinata, Sow., also teeth of fishes, namely, Cora falcatus, Ag.,
Lamna appendiculata, Ag., and Ptychodus mammullaris, Ag. Casts
of T'rigonie and Thetis (?) are not uncommon, but the pelecypoda are
generally in a condition which renders them difficult of identification.
Fragments of wood are also present, and large quartz-pebbles are not
infrequent. The fossils are most abundant in a band containing
phosphatic nodules. Tate gives the thickness as 8 feet 6 inches.

The glauconitic sand passes into a grey marl, the lower half of
which is crowded with Vermicularia concava, Sow., and V. quinque-
carinata, Rom., fragments of Pecten [Janira] also being noticed.
The greensand close to the point of junction contains yellowish
branching enclosures in great abundance, whose origin it is difficuit
to understand. In this upper layer a large Pecten |[Janira]
quinquecostatus, Sow., was found.

The marl, which in its upper part is of a dark blue-grey colour,
is not much more than 2 feet thick, the buff-coloured Yellow
Sandstones above, on the contrary, attaining a thickness of
30 feet, which, as Tate remarks, represents the greatest development
of the arenaceous series in Ireland. This rock, which contains
cherty masses, is markedly fossiliferous only along certain bands.
The fauna includes Ostrea [Alectryonia] carinata, Lam., Pecten
[Janira | quadricostatus, Lam. (of large size), Vermicularia quinque-
carinata, Rom. (not uncommon), Lima semisulcata, d’Orb., L. globosa,
Sow., Panopea mandibula, Sow., species of Avicula, Pinna, Trigonia
(a very fine 7’r. scabricula, Lyc., 1s probably from here), and Galeo-
laria plexus (Sow.). About 2 feet from the top a band rich in
Pecten {Janira} quinquecostatus was met with.

The Yellow Sandstones pass above into a greensand containing a
Cucullea and small Ostrea carinata, Lam. The Chloritic Sand-
stones here consist of alternating hard, calcareous, glauconitic
sandstones, and softer greensand rocks of the same nature, the latter
being those that are richest in organicremains. A noticeable feature

1 Quart. Journ. Geol. Soc. vol. xx. (1864) p. 103, & vol. xxiii. (1867) p. 297.

550 DR. W. FRASER HUME ON [ Dec. 1897,

is the presence of numerous brown nodules, similar to those occurring
in the Chloritic Marl.

Tate remarks that a lower band is charged with Vermicularia
concava, Sow.’ It is, however, a higher band that has attracted the
most attention, being full of large specimens of Hxogyra columba,
Lam., accompanied by an Ostrea (near biauriculata), Trigonia
crenulata, Lam., a Tellina or Anatina (probably the Anatina
Royana, d’Orb., mentioned by Tate), Oxyrhina Mantelli, Ag., Corax
falcatus, Ag., Ptychodus mammullaris, Ag., Pt. decurrens, Ag.,
and Lamna sulcata, Ag. Pecten asper, Lam., also occurs rarely
here, and Patellina [ Orbitolina] concava, Lam., 4 inch in diameter,
has been obtained in the glauconitic sandstone. ‘Tate also records
Cucullea fibrosa, Trigonia dedalea, Park., Pecten [Janira] equi-
costatus, Lam.?, Ostrea semiplana, Sow., and Ammonites [| Pachy-
discus | lewesiensis, Mant. I have been unable to obtain a single
specimen of the above ammonite, and an Ostrea semiplana from
Hannahstown, near Belfast, is from the Chloritic Chalk, a higher
horizon. The highest of the softer beds contains many specimens
of a crustacean, referred to Callianassa, which is accompanied by a
Natica and polyzoa.

The junction between these glauconitic sands and the higher beds
is very obscure, though in the upper part of the glen there is a
glauconitic sandy limestone containing Belemmnitella { Actenocamax |
vera (Mil.). This is the rock described by Gault as ‘hard green
speckled chalk, coarsely conglomeratic at the base; large rounded
pebbles of quartz and other rocks; the glauconitic grains are
very large and thickly scattered throughout, giving the bed its
well-known name of mulatto-stone. The fossils, except the
sponges and brachiopods, are broken and worn, being probably
derived from the waste of an older bed. Sponges are very numerous,
but other fossils are rare.’* The fauna corresponds in essentials
with that of the Chloritic Chalk in the Eastern Division, there being
here a distinct case of unconformity. This rock, which is very rich
in Ventriculites, and also contains Celoptychium, Echinocorys scutatus,
Leske, and fish-teeth, plays an important part in the district now
under consideration.

The hard White Chalk, 2 feet thick, which overlies this bed,
contains but few flints, and is immediately followed by white chalk
with flints arranged in regular rows. These upper beds will
probably repay further examination, so far as regards the detailed
distribution of their fauna.

Black Mountain and Crow’s Glen.

On the slopes of Black Mountain (1272 feet) are a number of
quarries, in which the upper strata of the series are better exposed
than is the case at Colin Glen. A little to the north, a very
complete section is obtained in a glen (Crow’s Glen), which differs
but slightly, either as regards thickness or character of succession,

’ Quart. Journ. Geol. Soc. vol. xxi. (1865) p. 24.
2 Proc. Belfast Nat. Field Club, n. s. vol. i. (1877) p. 256.

= ~~

Vol. 53.] | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 551

from that observed at the previous locality. In view of this fact, we
may content ourselves here with noting the variations observed.

1. At the base is a yellowish-green sand, which yielded
very delicate shells, resembling small Hxogyre.

2. The Glauconitic Sands are of the usual deep-green colour,
containing EHwogyra tevigata, Sow., in abundance, Pecten [Janira]
quinquecostatus, Sow., P. [| Amussium | orbicularis (Mant.), a Littorina-
like gasteropod, Vermicularia quinquecarinata, Rom., and an unde-
termined bivalve.

3. There is a passage upward into dark glauconitic marls,
which at the base contain Vermicularia quinquecarinata, Rom.

4, The Yellow Sandstone, of typical character, is here at least
25 feet thick, and, although not very fossiliferous, yielded Pecten
aequicostatus, Lam., Rhynchonella convexa, Sow., Vermicularia
quinquecarinata, Rom., V. concava, Sow., and fish-scales.

5. The ‘Chloritic’ Sands and Sandstones are also ei
developed, but whereas the fossils at Colin Glen were mainly in the
softer sandstones, here they are present in the harder beds. These
strata consist of three hard sandstone-bands separated by two layers
of softer greensand. In the lowermost hard stratum, Pecten equi-
costatus, Lam., and Vernucularia concava, Sow., are present, Rhyn-
chonella Schlenbachi, Dav., being also recorded. The second hard
band is full of Eogyra columba, Lam., to the apparent exclusion of
other organisms, while the soft quartzose greensand above contains
fish-remains (Lamna appendiculata, Ag., etc.). The hard glauconitic
limestone at the top of the series is apparently unfossiliferous.

6. There is no evidence of Chloritic Chalk in the glen itself,
but at the limestone-quarries blocks of this rock are lying about, the
original exposure being unfortunately hidden now. Large specimens
of Belemnitella mucronata, Schloth., and Echinocorys scutatus, Leske,
are abundant, accompanied by ammonites (not more closely identi-
fiable) measuring more than a foot in diameter, Baculites anceps,
Lam., Ventriculites, and Celoptychium.

The White Chalk itself contains Belemnitella mucronata,
Schloth., Jnoceramus-fragments, Lima Hopert, Defr., Nautilus
Atlas, Whiteaves, and Baculites anceps aff.

Forth River.

This stream, issuing from the hills, has cut a deep channel
through the basalts, and through the Cretaceous and Triassic rocks.

The lithological succession is not so clearly displayed as in
previous sections, the White Chalk with Belemnitella mucronata
resting directly on a hard glauconitic sandstone, which has given
rise to a small waterfall. The base of the latter rock contained
many specimens of a Belemnitella-like form, which Mr. Crick has
identified as Actinocamax Alfridi, Janet,’ a species of rare occurrence
in England. Spondylus spinosus, Sow., is also present. ‘The

1 See Janet, Buil. Soc. géol. France, ser. 3, vol. xix. (1891) p. 720, ete.

oo2 DR. W. FRASER HUME ON [Dec. 1897,

junction between the glauconitic beds (which contain in places
pebbles over 4 inch in diameter) and the Yellow Sandstone is
of a peculiar nature: the glauconitic rock enclosing many fragments
of the lower bed, while the latter in its upper part is crowded with
blocks of calcareous glauconitic sandstone.

The Yellow Sandstone itself is of the usual character, and a
Cucullea (C. ligeriensis, d’Orb., according to Tate), Vermicularie,
and thin-shelled pectens are the principal forms noticed.

The Glauconitic Sands were not observed here.

Squires Hill.

Several large quarries have been opened up here, in the second
of which (counting from the side nearest Cave Hill) the Chalk is
some 50 feet thick, and contains regular layers of flint. Fossils are
numerous at the base, including abundant Belemnitella mucronata,
Schloth., Hchinocorys scutatus, Leske, Terebratula carnea, Sow., tooth
of Lamna sp., Bourgueticrinus-stems, plates and spines of Cidaris,
Inoceramus-tragments, polyzoa, Ventriculites sp., Coscinopora sp.,
Parasmilia centralis, Mant., Kinyena lima, Sow., and Serpule.

Beyond this large quarry is a small one behind a farmhouse, in
which the lower beds of the series are well exposed, the rocks at
this point dipping steeply westward, and being apparently much
crushed owing to the movements to which they have been subjected.

At the base of the quarry, Glauconitic Sands of the usual
deep-green colour are well displayed, containing numerous specimens ~
of Kxogyra levigata, Sow., and Pecten [Janira| quinquecostatus, Sow.
When the quarry was first opened, Mr. R.S. Bell obtained a number
of fine casts of Cucullewa ligeriensis, and since then he has sent me
another, resembling a Ceromya, from the same locality. Total
thickness 4 feet 6 inches (this was determined for me by Mr. Bell).
The uppermost layer of this greensand is spotted with darker
patches, and is characterized by Vermicularia quinquecarinata,
Rom. .
In the Yellow Sandstone (18 feet thick), the only fossils .
observed were Vermicularie and a broken Pecten.

The soft greensand which succeeds it, 8 feet thick, yielded only
a solitary shark’s tooth, but the harder glauconitic sandy
limestone above is full of Belemnitella [Actinocamax| quadrata
(Blainv.), Echinocorys scutatus, Leske, and fragmentary sponges.
One of the most remarkable features at Squires Hill is the nodular
character at times assumed by the chalk containing B. quadrata.
A section taken across the nodules, which are brown to black
externally, shows them to consist of a glauconitic chalk, characteristic
of many of the Irish mulatto-stones.

The southernmost quarry is remarkable for two thin vertical
dykes which traverse the whole thickness of the Chalk. Mr. W.
J. Atkinson, F.G.S., has called my attention to the fact that, im a
microscopic section showing the junction of the basalt and the Chalk,
though the latter is thoroughly altered to a finely granular compact

Vol. 53. ] THE CRETACEOUS STRATA OF COUNTY ANTRIM. 553

limestone, yet many specimens of foraminifera situated close to the
line of junction appear practically unchanged.

Mr. Bell has sent me a number of specimens, from the
Chloritic Chalk and base of the White Limestone at this quarry,
which show that the nodular rock is crowded with Belemmtella
[ Actinocamaax| quadrata and Micraster cor-anguinum, Forbes, <A.
Alfridi being also present. The Chalk immediately above this bed
contains Turritella unicarinata, Woodw., fine pectens, Pleurotomarie,
and a gasteropod of doubtful genus. ' Nautili and Ammonites appear
to be fairly common, but the latter are not perfect enough to admit
of closer identification.

Cave Hill.

At the top of the tramway-line leading to the large quarry cut
in the side of this hill, the Glauconitic Sands, of a deep green
colour, overlie strata of Liassic age. The fossils are most abundant
in a hard rusty-brown layer, and include Hwogyra laevigata, Sow.,
Pecten| Janira | quinquecostatus, Sow., P.{ Chlamys | Dutempler, d’Orb.,
or P. Gallienne, d’Orb., Belemnites ultimus, d’Orb., and large bivalves
in the form of casts, which have some external resemblance to Thetis
Sowerbyi; Vermicularia quinquecarinata, Rom., and P. { Amusstwm |
orbicularis (Mant.), also occur, but very rarely. Above the fossili-
ferous layer, the rock was of a deep brown colour, and barren oi
fossils.

The Yellow Sandstone is very nodular at this point, and
contains large chert-fragments; in its upper part it is filled with
blocks richer in glauconite, and is overlain by a true glauconitic
sandstone.

The Chloritic Sandstone has yielded numerous fish-remains
(notably Coraw falcatus, Ag., Ptychodus latissimus, Ag., Lt.
mammallaris, Ag.) and Ostrea semiplana, Sow.; while in the pink
glauconitic chalk.above, Spondylus spinosus, Sow., is most
noticeable.

The White Chalk itself is very rich in organisms, especially at
the base. These include Belemnitella mucronata, Schloth., Echinocorys
ovatus, Lam., Ventriculites, Rhynchonella plicatilis, Sow., and Lh.
limbata, Dav. In addition to these may be mentioned Notidanus
microdon, Ag., Anomeodus sp., Hamites, Nautilus Largilliertianus,
d’Orb., V. Deslongchampsianus, d’Orb., Amm. [ Pachydiscus | Oldhami
(Sh.)— Pach. Portlocki (Sh.) is recorded by the Geological Survey,—
fine specimens of Zima (which apparently belong to a new species),
Pecten sp., Pleurotomaria perspectiva, Mant., Terebratulina striata,
Wahl., of large size, and differing from the typical 7. Defrancei,
Brongn., in being more depressed, Galerites conicus (Breyn.), a
Trochosmilian coral, and Ce/optychium belfastiense, Tate. _

The quarry at Whitewell is famous as being the locality where
remains of Mosasaurus gracilis, Owen, have been discovered, and
these have been mentioned by Mr. Swanston in a short paper.’

Proce. Belfast Nat. Hist. & Phil. Soc. 1886, pp. 18-19.

554 DR. W. FRASER HUME ON [Dec. 1897,

The Central Division is characterized :—

Lithologically:

1. By the great thickness of those beds which are clearly of
detrital or chemical origin, namely: the Glauconitic Sands,
Yellow Sandstones, and Chloritic Sandstones.

2, By the marked unconformities existing between the detrital
deposits and the calcareous beds of organic origin.

3. By the frequency of a nodular layer at the base of the
limestone series.

Zonally:

4, By the prominence and richness in organic remains of the zone
of Exogyra columba.

5. By the extreme reduction, if not entire absence, of the zone
characterized by fragments of Jnoceramus and Spondylus
spinosus (see next division).

6. By the exceptional development of the zone of Belemnitella
(Actinocamax) quadrata, especially at Squires Hill.

Paleontologically:

7. By the abundance and large size of the Dimyarian Pelecypoda,
especially the genera Trigonia and Cucullea, and forms
like Thetis, in the Glauconitic Sands and Chloritic Sand-
stones; and the large size attained by the Monomyarian
Pelecypoda at the base of the White Chalk, and by Ostrea
carinata in the Yellow Sandstone.

8. By the great development of gasteropoda and cephalopoda in
the lower beds of the White Chalk.

9. By the abundance of fish-remains in the zone of Hxogyra
columba.

(3) Tae Eastern Division,

from Belfast to Larne (including Islandmagee).

The Geological Survey Memoir, Expl. Sheets 21, 28, & 29, states
that White Chalk and Chloritic Sandstone have been met with east of
Carnmoney Hill, but it is impossible from the description to under-
stand the stratigraphical distribution of the fossils, which include
Belemmitella mucronata, Schloth., Spondylus spinosus, Sow., Inoce-
ramus Crispi?, and Micraster cor-anguinum, Forb. Between Carn-
money Hill and Woodburn Glen, a distance of 5 miles, there are
no important exposures of the Cretaceous rocks, but at the latter
locality two very complete sections of these strata are observable,
formed by two streams which cut through the hill at this point. As
these exposures present almost identical features, the one supple-
menting the other in details only, their description will be united.

These beds, which have been taken as types both by Tate and
Barrois, have been also selected as the most suitable for examination

Wolk s3:] THE CRETACEOUS STRATA OF COUNTY ANTRIM. 590

by analysis and microscopic study, and the observations resulting
therefrom will be dealt with in the sequel.

The Glauconitic Sands, which here attain a thickness of
nearly 8 feet, are very fossiliferous, especially in a nodular band
at the centre of the zone, termed by Tate the bed of Ewegyra conica.
Some of these Hwogyrw measure as much as 2 inches or more
in diameter. In addition Pecten [Amussium] orbicularis (Mant.),
as also species of Arca, Inoceramus, and Avicula, attest the great
richness of the molluscan fauna at this period. The conical casts
of biconcave vertebre of fish have also been obtained. Moreover,
Tate records Belemnites ultimus, Pecten [Chlamys| Dutemplei, P.
virgatus, and TLerebratula squamosa.

The greensands graduate into a dark sandy marl dotted with
green glauconitic grains, the Glauconitic Marls, which stratum
forms a connecting-link between the Grey Marls above and the
Glauconitic Sands below.

The Grey Marls become very light in the upper part, where
ramifying masses of a glauconitic sandy limestone are scattered
through them, similar to the rock next to be described. The
marls, so far as I have observed, are quite unfossiliferous; but,
as they contain cherty nodules, they are in all probability merely
a more clayey facies of the Yellow Sandstone, and are in fact
quite as rich in detrital material as the Yellow Sandstone of Colin
Glen.

In the chemical analysis, the marl and enclosed grit have been
separately treated, and in Table II. [facing p. 584] are respectively
numbered 4 and 4a. Tate gives the marls a thickness of 27 feet,
but my measurements assign 14 feet to the glauconitic dark marls,
and 13 feet to the yellower marls above, or a total of 3 feet.

The Grey Marls are succeeded by a calcareous glauconitic
sandstone similar in its nature to the one above-mentioned, and
the peculiar inclusions already referred to bear out Tate’s contention
that there is an unconformity between this rock and the underlying
strata. The series shows a gradual change upward, from this
sandy type to a sandy glauconitic limestone at the summit, but
about a foot from the base occurs a band, which, from the ease with
which it is identified, has been used by previous authors as of con-
siderable importance in their discussions.

Its characteristic feature is the presence of innumerable fragments
of IJnoceramus scattered through a calcareous matrix, rich in
glauconite- and sand-grains. I have been unable to obtain any
proof that the Inoceramus present is I. Cripsw, Goldf., non Crispi,
as suggested by Tate and others, though in his paper there is a
question-mark against the name. On the other hand, neither has
any further evidence been forthcoming of their connexion with
I, Brongniarti, Park., although, judging from their associated fossils,
they may possibly be referable to that species. The only perfect
specimen of Jnoceramus that I have been able to examiue from
this horizon hails from Armoy, and is a genuine J. Brongniarti.

The principal fossils obtained by me at this locality were

556 DR. W. FRASER HUME ON [Dec. 1897,

Spondylus spinosus, Sow., Pecten [Janira] quinquecostatus, Sow.,
aud Terebratula carnea, Sow. A Crdaris-spine and Ostrea semiplana
have also been obtained, the Crdaris noted here having always
been classed with C. subvesiculosa, d’?Orb. Of the greatest interest,
perhaps, is the occurrence of Achinocorys scutatus var. gibbus, Lam.,
at this horizon, two characteristic specimens being obtained
by me in the northern glen, and these were in close connexion
with the fragmentary Jnocerami, Spondylus, and Jana. Special
stress must be laid upon the occurrence of this sea-urchin at
this locality, because Tate has placed the Jnoceramus-band in the
Lower Chalk, or Cenomanian, and Barrois does not appear to have
obtained it here. In addition Rhynchonella robusta, Tate, a well-
marked variety of Ah. limbata, Dav., occurs at this horizon.

If some of the Jnoceramus-shells be placed in dilute hydrochloric
acid, the greater portion of the shell dissolves away, leaving an
open hexagonal mesh of siliceous material behind. Mr. Chapman
has obtained similar results in the Bargate Beds, and has also
shown me a section in which chalcedony occurs between the prisms
composing the Jnoceramus-test. It would appear that silicification
in this case is interprismatic, and not, as in so many familiar
instances, the replacement of the calcareous prisms themselves by
silica. These results throw light on the structures obtained by
me in the /noceramus labiatus-zone in the Isle of Wight,! which
at the time were doubtfully referred to sponges, but are evidently
identical with those just described.

Above the Jnoceramus-band the character of the rock remains —
apparently unaltered for a thickness of about 2 feet, but in its
upper part some large pelecypoda were observed, lying parallel to
the bedding, and all on the same horizon. The hardness of the
rock prevented their extraction in fragments sufficiently large for
identification, but the appearance suggested a form of Spondylus.

The Chloritic Chalk, which follows next in succession, is
a pinkish white limestone, about 4 feet thick, having brown nodules
from | inch in diameter downward scattered through it, while the
limestone itself 1s dotted with green grains of glauconite. This
appears to be the equivalent of the Spongiarian zone of Tate, and
is characterized by the presence of beautiful internal and external
casts of many foraminifera and sponge-spicules. From the
thicknesses given by Tate and Barrois it would appear that the
upper part of this: limestone was included by them in the White
Limestone, but in the section in the southern glen, where the
Chloritic Chalk was more especially studied, no direct contact with
the latter rock (containing Belemnitella mucronata) was observed
by me.

In the upper part of the glen the White Limestone with
flints 1s well displayed, though much disturbed by the intrusion of
numerous dykes of basalt. The chief fossils are Belemnitella
mucronata, Schloth., and Khynchonella octoplicata, Sow.

1 «Chemical and Micro-Mineralogical Researches on the Upper Cretaceous
Zones of the South of England, London, 1893, p. 48.

Vols 3.| THE CRETACEOUS STRATA OF COUNTY ANTRIM. 507

The Cretaceous exposures north of Woodburn Glen, in Island-
magee, are among the most interesting of the whole series, and as
many of these have been but lightly touched upon by previous writers,
it may be advisable to deal with them more fully here. Near
Castle Dobbs, 3 miles north-east of Carrickfergus, the officers of the
Geological Survey observed a chloritic sandstone, containing abundant
specimens of Terebratula carnea, Sow., small Exogyra columba, Lam.,
Inoceramus sp., Spondylus spinosus, Sow., Echinocorys scutatus,
Leske, and a Galerites hesitatingly referred to G. subrotundus
(Breyn.). At Seamount, about 4 miles north-east of Carrick-
fergus, the chloritic sandstone has also been recorded by them, but
with quite a distinct fauna: Rhynchonella limbata, Dav., Serpula
[| Galeolaria| plexus (Sow.), and Lamna acuminata, Ag., being the
principal occurrences.

Whitehead.

The Glauconitic Sands, which were well exposed during the
construction of the tunnel between Carrickfergus and Whitehead,
have been described by Tate. At the present time the lower
strata are not clearly exhibited, though south of the tunnel
Mr. Bell found a glauconitic sandstone crowded with Rhynchonella
Schlenbachi, Dav., a fossil which appears to be especially
characteristic of the lower part of the Chloritic Sandstone, or zone
of Exogyra columba.

South of Whitehead is a large chalk-quarry, now unworked, in
the upper part of which the somewhat flattened flints are in regular
layers, these becoming more scattered and irregular towards the
base of the section, the chalk at the same time being of a more
bluish tint. In the lower part of the quarry, large ammonites
were very abundant, and have been commonly referred to A. lewes-
iensis, Sharpe. As under this name several species possibly may be
included, a revision of the specimens obtained at this locality would
be advisable, but it is doubtful whether any remain in a sufficiently
good state of preservation to admit of a more accurate determination.

.On the sea-shore at Whitehead the base of the Chalk is exposed,
here consisting of a compact white limestone containing Belemnitella
[Actinocamax] vera (Mil.). A layer of tabular flints separates
this from the Spongiarian zone, characterized by the abundance
of the sponge-remains. The upper part of this band consists of a
limestone full of green nodules, which in most cases show distinct
sponge-structure. In the lower portion the sponges are closely
crowded, and include Ventriculites cribrosus. Phil., V. radiatus,
Mant., Coscinopora infundibuliformis, Goldf., Etheridgia mirabilis,
Tate, probably Plocoscyphia, and possibly Becksia.

A glauconitic sandy limestone full of Jnoceramus-fragments
completes the section, the rocks lower than this being covered by
seaweed, and only visible at low tide.

From Whitehead a path passes round Blackhead, a bold head-
land formed by the Lower Amygdaloidal Basalt. The amygdaloidal

558 DR. W. FRASER HUME ON [ Dec. 1897,

cavities in this rock have been drawn out parallel to the direction
of flow, and zeolites have been abundantly formed in the vesicles.
A quarter of a mile to the north-east, a little south of Cloghfin
Harbour, the Cretaceous rocks are well exposed on the shore,
especially at low tides. The beds dip 8.W. at an angle of about 5°,
and every member of the series is clearly visibie. The order of
succession 1s as follows, commencing from the top :—

1. Compact limestone, crowded with green sponge-nodules
6 inches thick. This band forms the summit of a low platform,
which gradually slopes south-westward, and is undoubtedly the same
as that previously mentioned as occurring on the shore at White-
head.

2. Limestone, much jointed, and readily breaking into flakes
an inch or more thick, characterized, as in the previous case, by the
great abundance of sponge-remains, these forming a particularly
well-marked layer at the base. The species are the same as those
mentioned above, Ventriculites cribrosus, Phil., and LHtheridgia
mirabilis, Tate, being especially characteristic. Total thickness
= 32 feet.

3. The Chloritic Chalk and Sands are well exposed in a low
cliff running parallel to the strike of the beds, the summit of which
is formed by the base of the Spongiarian zone above-mentioned.
In the upper part, which is really a glauconitic limestone, Kchino-
corys gibbus, Lam., is abundant. Other fossils obtained by us at
this level were Parasmilia centralis, Mant., Bourgueticrinus (portions

of stem), Cidaris-spines, probably C. sceptrifera, Mant., Terebratula ©

carnea, Sow., Spondylus spinosus, Sow., Haoyyra near plicata,
Inoceramus-fragments, and numerous sponges. Total thickness
=3 feet.

4, At this point a band of Serpula filiformis is easily recognizable.
The lower part of the cliff is less fossiliferous, though three
Inoceramus-bands are well-marked, the lowest, 2 feet 8 inches from
the Serpula-layer, being composed of larger fragments. Numerous
branching forms, apparently of polyzoan nature, are present at
this level, and a little below it I obtained an example of G'alerites
albogalerus, var. angulosus, Desor.

5. The remaining 2 feet 6 inches consists of soft glauconitic
sands, which, with the above exception, did not yield fossils.
The base of these beds is hidden by pebbles and seaweed, but the
thickness of the strata thus obscured must be at least 4 feet,
calculated by pacing.

6. The Yellow Sandstones and Marls (cropping out in a
step-like manner, the latter being more rapidly denuded) are here some
8 feet thick, and consist of alternating strata of compact calcareous
sandstone and softer marls. In the latter iron-pyrites nodules are
not uncommon, and in the sandstone-bands are many peculiar dark
branching bodies, occasionally divided into several segments. High
up in the series occur large specimens of Pecten { Janira| quadri-
costatus, Sow., while Vermicularia concava, Sow., and V. quinque-
carinata, Rom., are very abundant. These species of Vermicularia

Vol. 53. | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 559

are also present in the Glauconitic Marls near the base, these
being separated from the Glauconitic Sands by a band of compact
yellow sandstone.

7. The Glauconitic Sands are well exposed at low tide, and are
of the usual blue-green colour. Fossils are very abundant. Hxogyra
conica, var. levigata, Sow., Pecten [| Amussium] orbicularis (Mant.),
and P. [Janira] quinquecostatus, Sow., are large and numerous.
P. [Chlamys] asper, Lam., and P. Galliennii, d’Orb., are by no
means uncommon, and a special feature is the abundance of
small brachiopoda, especially Rhynchonella near Cuvieri, Sow.,
Terebratule (TL. squamosa, Mant., or stunted 7. biplicata, Sow.),
Kingena lima, Defr., and an unidentified species. Turbinate
gasteropoda (? Littorina), Avicule of different species, teeth of fishes
(apparently Zamna appendiculata, Ag.), and a belemnite which fore-
shadows the characters of Belemnitella [ Actinocamax] vera, but is

much longer and thinner, were also obtained. Thickness, over 4 feet.

The upper part has yellow spots sprinkled through the deep-green
matrix, and yielded no fossils.

Hillsport.

No continuous sections are to be observed north of the exposure
just described, but blocks of the various types are plentifully
scattered along the shore. The Spongiarian layer is particularly
prominent, as weathering causes the sponge-fragments to stand out
in branching masses on the surface of the rock. Hchinocorys
scutatus is also abundant, so too is Camerospongia fungiformis,
Goldf., and casts of lamellibranchiata.

The character of the Chloritic Sands was well illustrated
in a large mass which had slipped down the hillside. Instead of
the fossils being irregularly scattered throughout the rock, clearly-
marked bands are noticeable, the succession being :

Depth below
Sponge-layer.
1. Sponge-layer. Ft. ins.
Dp SCN Pula fULOR TIS ROO Mee: foo S88 Safe ii dak wadew dedavacdoende 0 6
(In addition to the Serpule, large Inocerami and
Spondylus spinosus were present.)
pH INS WO COMOES IMM Se. ceeds aves ssa llnocaastiieie tennceancaes 3
. Second i

Pee oe see sees sssesseseseseessssensesH FHtHsseae

on oo
Or
MOD

(It contains abundant examples of Fh. plicatilis, Sow.,
Eh. limbata, Dav., and Rh. robusta, Tate. At the
base specimens of Catopygus columbarius, Lam., are
not infrequent.)

Of other fossil forms, Echinocorys scutatus and Terebratula
carnea are mainly restricted to the upper part, while spines of
Cidaris are present throughout the whole series. Jnoceramus-

560 DR. W. FRASER HUME ON [Dec. 1897,

fragments occupy the central portion, Ostrea semiplana and the
branching bodies are only in their own band, and the Rhynchonelle
are mainly restricted to the lower 3 feet.

The Yellow Sandstone is comparatively rich in fossils, these
including Vermicularia quinquecarinata, Rom., Ditrupa difformis,
Lam., Pecten [Janira] quadricostatus, Sow., Rhynchonella convexa,
Sow., and Lamna appendiculata, Ag. This is the only locality
where sea-urchins and corals have been recorded from this horizon,
Micrabacia coronula, Goldf., being frequent, and Discoidea subuculus,
Klein, not uncommon. We pbc” a larger echinoderm here,
but it was too imperfect to admit of identification.

The Glauconitic Marls are displayed beneath the sandstone,
and Glauconitic Sands occur from time to time, containing a
Pecten asper of large size.

Barney’s Point, near Mill Bay, west side of Islandmagee.

On the eastern side of Islandmagee, 2 miles north of Ballycarry,
occurs a large quarry which must at one time have been extensively
worked, but now appears to be deserted. A cutting has been
carried through the Cretaceous rocks, presenting one of the finest
sections of these visible in Co. Antrim. Commencing from the
top, we observe :—

1. Chalk with regular layers of flints, passing below into
chalk with scattered flints, which contains Belemnitella mucronata,
Nchloth., Echinocorys scutatus, Leske, Crdaris-spines, polyzoa, and
Porospheera.

2. A flaky chalk, 4 feet thick, probably represents the Spon-
glarian zone, which was not so Clearly recognized paleonto-
logically as at Whitehead.

3. The Chloritic Chalk and Sands merge one into another,
forming a rock of distinctly green tint, 20 feet thick. Fossils are
extremely abundant, and special bands are very clearly marked.
The principal may be thus summarized :—

(a) Near the upper part of the series is an EHchinocorys scutatus-band, in
which Spondylus spinosus and Camerospongia fungiformis are also
abundant. The rock is a glauconitic limestone.

(0) Serpula filiformis-band.

(c) The distance from 6 to the upper Jnoceramus-band is probably between
3 and 42 feet; below is a second Jnoceramus-layer, also containing
Ostrea semiplana and numbers of small Rhynchonelle (Rh. limbata,
Schloth., and Rh. robusta, Tate). The third layer of Inoceramus-
fragments is at the base of the series, 2 feet below the second band,
and contains Rhynchonella plicatilis, Sow., Catopygus columbarius,
Lam., Cidaris-spines, and probably Psewdodiadema variolare, Brongn ,
and Micraster breviporus Ag. (in casts only).

(d) Yellow-green sands, 4 feet thick, containing Vermicularie, a small
Ostrea carinata, Sow., a cast of Hrogyra columba, Lam., and Ostrea
semtplana, Sow.

This section is of especial importance, as showing that the zone
of Exogyra columba is below that of Jnoceramus Crispi?, and not

Vol.53.] | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 561

above it, as suggested by Tate. By combining the previous two
sections together we are now enabled to range these beds by means
of their fauna as follows :—

ZONE. Sub-zone.
( Echinocorys gibbus.
Serpula filiformis.
Spondylus spinosus or j Ostrea semiplana = main Inoceramus-
Inoéeramus sp. 1 beds.
| Rhynchonella plicatilis.
( Catopygus columbarius.

DOGG COMB A i TB Ec aen acs odsiannxe ost

Spondylus spinosus is found throughout the series, except in d,
while Terebratula carnea is restricted to the upper part. The
Yellow Sandstone here attains a thickness of 20 feet, chert being
developed in thick bands, at regular intervals throughout the
whole rock; but the organic remains appear to be few, a possible
Ostrea carinata and Rhynchonella of unrecognized species being
alone noted in the highest chert-band. At the base some 4 feet of
Glauconitic Sands are exposed, these containing small Exogyre
and a Pecten of doubtful species. On the opposite side of Larne
Lough, at Redhall, a mile north of Ballycarry, the officers of the
Geological Survey record chloritic sandstone, and judging from the
number of sponges mentioned, including Achillewm fungiforme and
species of Coscinopora, Siphonia, and Ventriculites, it seems highly
probable that at least the base of the Spongiarian zone is
represented. Moreover, the presence of Terebratula carnea (com-
mon), Z. semiglobosa, Rhynchonella plicatilis, Exogyra columba
(small), Inoceramus-fragments, Spondylus spinosus (common), Echi-
nocorys scutatus, Micraster cor-anguinum, Lamna acuminata, and
Ptychodus latissimus, strengthens the view that the main body of
the Chloritic Sandis here represented. It should be noted that
Galerites subrotundus is also recorded from this locality.

. Magheramorne.

At this village, situated on the western coast of Larne Lough, oppo-
site Barney’s Point, is the large Magheramorne chalk-quarry. The
limestone has been analysed by members of the Belfast Naturalists’
Field Club, the result being as follows :-—

Carbonate of Limoe..............-.0s0< 98°63°/,
Carbonate of magnesia ............ 0°38°/,
Phosphate of lime | .....00..-2<rn00¢ 0°10°/,
Oxide of lime and alumina......... 0-08°/,
Silica and insoluble clay ............ 0°45°/,
99°64

For the present writer’s analysis, see p. 578.

Glynn.

The character of the rocks at this locality has been noted by
Dr. C. Barrois, but no facts of importance arise from their study.
The succession and thicknesses are :—

Q. J.G28: No. Ziz. 2P

562 DR. W. FRASER HUME ON © [Dec. 1897,

Feet.

1, ‘Clralk’ with litt §..05. cet .ccsserntorsseencensaodcedeste eee aeeeee 70
2. ‘Chioritie Chialllern. cnsit.gasscatas cc tene ee seo ee ae eee 6
&. Chioritic Samds) 255.4 sede,agecceccnecetemiese socee sc eee eee 43
4. Calcareous yellow sandstone with branching masses ...... 3
5. Glaniconttic Samds: | wiser ees ise: to necnathosasi-eote eee eee eeeee 10
934

In the latter only Exogyra levigata, Sow., and Pecten [Janira]
quinquecostatus, Sow., have been recorded.

Larne.

A mile north of Larne, near Waterloo House, is a remarkable
exposure of the Chloritic Sands, of a distinct red colour. It is of
particular interest, as being one of Dr. Barrois’s type-localities for

beds of Turonian age. The beds are in succession, beginning from
above :—

(a) White Chalk with irregular flints, containing Belemnitella mucronata
and Echinocorys scutatus.

(6) Chloritic Chalk, very nodular.

(c) Red glauconitic siliceous limestone (part of Chloritic Sands ?).

Barrois has recognized three bands in this rock, and I shall place
the list of fossils collected by Messrs. Stewart, McLean, and myself
side by side with his list, as ours differs in very material particulars.’

Barrois. Present Paper.
Spondylus spinosus, Sow. Spondylus spinosus, Sow.
Pecten [ Janira] quinquecostatus, Sow. | Pecten [Janira] quinquecostatus, Sow.
Terebratula hibernica, Tate. Inoceramus-fragments.

Rhynchonella Tolliezana, Cornet- Rhynchonella plicatilis, Sow.
Briart (near plicatilis). robusta, Tate.
Terebratula carnea, Sow.
semiglobosa, Sow.

In lower part only:

JInoceramus-fragments. Cidaris-spines.

Rhynchonella robusta, Tate. Echinocorys scutatus, var. ovatus
Cuvieri, Sow. (type), Lam.

Terebratula semiglobosa, Sow. Galerites albogalerus, var. angulosus,

Cidaris subvesiculosa, a’ Orb. Desor.

Galerites subrotundus, Breyn., sp. Ostrea semiplana, Sow.

Casts of bivalves. Teeth of fishes (probably Coraz).

Camerospongia fungiformis, Goldf.

The rock is sometimes distinctly oolitic. It will be seen, on
examining the above lists, that mine differs from that of Barrois in
giving the rock a higher zonal position than that assigned to it by
him. For example, we failed to obtain the two distinctly Turonian
forms, Rhynchonella Cuviert and Galerites subrotundus, at the same
time noting the presence of Echinocorys scutatus and Galerites albo-
galerus, the latter of atype much more characteristic of the Senonian.

1 T gather that the part of this rock which we found most fossiliferous

would correspond most nearly with D 6,7, and 8 of Barrois, ‘ Recherches

sur le Terrain Crétacé Supérieur de l’Angleterre et de l’Irlande,’ Lille, 1876,
p. 211.

Vol. 53.] | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 563

This matter will be more fully dealt with when discussing the
general stratigraphical relationship (p. 594).

Besides the Inoceramus-band which was accompanied by this
rich fauna, two others occur, but these did not yield any other fossil
forms. A yellow-green sandy layer separates the red glauconitic
limestone from a flaky yellow sandstone appearing at the base.

The Sponge-layer bed was observed on the shore at Waterloo,
above it being the layer with green sponge-nodules.

Inland, at Ballycraigie Bridge, near Killyglen, a pink chalk was
seen, containing Ventriculites, Rhynchonella sp., Spondylus sp.,
Ostrea vesicularis, Lam., and Belemnitella mucronata, Schloth.

At the time of our visit, a cutting was being made in the road,
the upper part of which was composed of yellow, the lower of bluish-
green sands. The presence of Vermicularie in the upper part
makes it probable that these beds represent the Yellow Sandstones,
Glauconitic Marls, and possibly the Glauconitic Sandstones.

Ballygalley Head.

A little to the south of this head, nearly 4 miles north of
Larne, Barrois examined an interesting exposure. A band of
rolled nodules separated the white chalk-with-flints from a slightly
glauconitic limestone (1 foot thick), this again overlying 3 feet
of hard glauconitic limestone, very rich in fossils. These include
Belemnitella sp., Serpula, Inoceramus sp., Ostrea canaliculata,
d@Orb., O. semiplana, Sow., Spondylus spinosus, Sow., Terebra-
tula senviglobosa, Sow., Rhynchonella plicatils, Sow., Cidaris
sceptrifera, Mant., Galerites conicus (Breyn.), Echinocorys gibbus,
Lam., Parasmilia centralis, Mant., and numerous sponges, notably
Camerospongia fungiformis, Goldf., and Etheridgia mirabilis, Tate, a
fauna which in many respects resembles that of the red rock at
Waterloo, and is very similar to that of the glauconitic limestone
below the main sponge-bed at Blackhead.

Beneath the limestone is a very sandy glauconitic rock, a bed
consisting of fragments of Inocerami, associated with pebbles, while
the base of these Chloritic Sands consists of a soft sandstone, con-
taining large grains of quartz and glauconite, the only ZOseH observed
being Spondylus spinosus.

The Yellow Sandstone is possibly represented a a soft sand-
stone containing cherty nodules.

The White Chalk between Ballygalley Head and Glenarm pos-
sesses a very simple fauna, Belemmtella mucronata, Schloth., Rhyn-
chonella octoplicata, Sow., Rh. limbata, Schloth., Hchinocorys scutatus,
Leske, and Magas pumilus, Sow., recurring with monotonous regu-
larity. Only at one locality, 2 miles south of Glenarm, were the
lower beds visible. There the succession is, beginning at the top :—

1. Chalk with regular layers of flint.

2. Chalk, with irregularly-scattered flints, having a nodular character at the

base.
3. Glauconitic Chalk, 2 feet below becoming
4, Quartzose glauconitic limestone with pebbles # inch or more in diameter.
2P 2

564 DR. W. FRASER HUME ON [ Dec. 18975

This band contained Jnoceramus-fragments in large quantity, as also Spondylus
spinosus, Sow., Terebratula carnea, Sow., and Cidaris-spines; Ostrea semiplana,
Sow., occurred a little higher up. Vegetation obscures the beds below, but
these can be seen to consist of greenish-yellow sands, from which no fossils
were obtained.

Between Glenarm and Carnlough the ground is very much broken,
landslips having taken place on a considerable scale. The conditions
recall those observed in Islandmagee, the bed with green sponge-
nodules, of the Spongiarian zone, being visible in one quarry, while
the sponge-floor with Ventriculites and Coscinopora is also probably

resent.

Isolated blocks of glauconitic sandstone were also found
by us, containing pebbles 4 inch in diameter, abundant Inoceramus-
fragments, Terebratula carnea, Sow., and a Rhynchonella (possibly
plicatilis). This district is also characterized by the abundance of
Spondylus spinosus, Sow., and Ostrea vesicularis, Lam. Gasteropoda,
such as Plewrotomaria and Turbo, fishes (Corax maximus, Lamna
acuminata, Ag., L. appendiculata, Ag., and Ptychodus mammillaris,
Ag.), and several species of Zima have also been recorded by the
Survey.

North of Garron Point, the officers of the Geological Survey
record two exposures of glauconitic conglomerate, the one
near Milltown, the other near Retreat Castle, 2 miles south-west of
Cushendall. This rock (which is referred to the Upper Greensand
in the Geological Survey Memoir, Expl. Sheet 14) is described as
a bed about 12 inches thick, composed of pebbles of vein-quartz
and Lias nodules, in a glauconitic (‘ chloritic’) sand. Terebratula
carnea, Sow., Inoceramus sp., Pecten [ Janira] quinquecostatus, Sow.,
and Lamna appendiculata, Ag., are the principal fossils. It will
thus be seen that it is probably identical with the rock examined
by us at Carnlough.

The Eastern Division is characterized :—
Zonally:

1. By the reduction in thickness, or total absence, of the zone of
Exogyra columba. :

2. By the great development of the glauconitic sandy limestone
containing fragments of Jnocerami and Spondylus spinosus,
the zone of Inoceramus Crispi of Tate.

3. By the presence in the above zone of definite fossil-bands.

Paleontologically:

4. By the abundance, in the Glauconitic Sands, of Pecten
[Chlamys] asper, P. Galliennet, and small brachiopoda.>

5. By the frequent occurrence of sea-urchins in the Yellow
Sandstone and at the base of the Chloritic Sands.

6. By the existence of a Hexactinellid sponge-floor at the base
of the White Limestone.

This division includes Tate’s most typical sections, and it is here
that Barrois obtained the evidence which led him to recognize the

Vol. 53.] | THE CRETACEOUS STRATA OF COUNTY ANTRIM, 565

existence of Turonian strata in Ireland. It is in view of these
facts that I have dealt at some length with the description of this
district.

(4) THe Pentysvtar or Insviar Division.

(Between Cushendall and Ballycastle, and Western
Cretaceous exposures of Co. Derry.)

North of Cushendall the coast consists mainly of rocks far older
than the Cretaceous, though on the hill-slopes patches of Chalk are
from time to time visible under the cappings of basalt. In one
locality only, namely, at Murlough Bay, near Ruebane Point, 6 miles
east of Ballycastle, the junction of the Chalk with the underlying
beds is clearly displayed. (See Pl. XLIV.) Here the red Triassic
sandstone is separated from the White Limestone by a well-marked
conglomerate, a foot thick, consisting of pebbles of quartzite, 1 inch
in diameter, vein-quartz, mica-schist fragments (these sometimes
also included in the Chalk above), red sandstone, and Lias nodules,
the whole being enclosed in a glauconitic limestone. Fossils are
sparsely distributed, Rhynchonella octoplicata, Sow., being the most
conspicuous species present.

As the white limestone here rests so closely on beds of sandstone,
it seemed advisable to take samples of the chalk from different levels
above the Pebble-conglomerate, with a view to determining whether
denudation of the land had ceased suddenly, or whether there had
been a gradual diminution in the quantity of detrital material.
Consequently, specimens were selected from the Pebble-conglomerate,
and from the immediately overlying Chalk, the remaining three
samples of chalk being obtained at intervals of 6 feet above. The
results are described in the Chemical Section, pp. 579-584 &
Table IT. :

The best sections in this division are, however, to the west in
Co, Derry, and are as follows :—

Magherafelt, Moneymore, and Tamlaght.

Prof. Judd has placed in my hands a collection made by him
at Moneymore, which clearly shows the presence of an important
Cretaceous beach at this locality. The quartzite and quartz-
schist pebbles here attain considerable dimensions, one being over
3 inches long, 2 broad, and 2 thick. Associated with these
are a number of organic remains, including abundant specimens
of Galerites abbreviatus, Goldf. (very small and low, and showing
but little trace of the original structure), gasteropoda (Trochus
or Turbo, Acteon, Emarginulina), pelecypoda (Venus sp., Pecten
[Janira] quinquecostatus, Sow., Inoceramus-fragments), also a much-
rolled Actinocamaz, in outline resembling A. Alfridi, and other forms
which do not permit of absolute identification. (For Cretaceous
beaches, see p. 601.)

566 DR. W. FRASER HUME ON [ Dec. 1897,

Formerly there appears to have also been an important exposure
at Tamlaght, near Coagh, Portlock recording it thus :—‘ The lower
portion of the chalk is here a very curious pebbly or conglomeratic
bed, with much green matter, but still containing many fossils of
the lower chalk or grey marl, such as Ammonites lewesiensis, Nau-
tilus elegans, var., N. radiatus, @Orb.,’ Baculites Faujasit, Hamites
sp., Inoceramus Cripsir, Cardium decussatum, etc. Its total thickness
is about 30 feet, and it rests on the variegated shales or marlsof the
New Red Sandstone.’? In addition, he mentions Ventriculites radi-
atus, Mant., and Holaster planus (Mant.), (small specimens -6 inch
long). chinocorys ovatus, Lam., Catopygus columbarius aff., and
Belemnitella mucronata, Schloth., have also been recorded.

Respecting Ammonites lewesiensis, Sowerby remarked, ‘ These
specimens lead me to suspect that -A. lewesiensis is only a com-
pressed variety of A. peramplus. Those obtained at Tamlaght
very closely resemble Mantell’s original examples. This species is
said to be abundant in the lower or glauconitic portion of the
western chalk, and seems to mark a distinct bed along its escarp-
ment. The rock itself consists of a pink chalk, with a few glauco-
nitic grains scattered through it.

Slieve Gallion.

In this district the Chalk beds overlie the Keuper marls, being about
30 feet thick near Coagh. The Geological Survey Memoir, Expl.
Sheet 26, p. 28, states that, in a stream south of the large quarry N.W.
of Spring Hill, the lower part of the Chalk is a compact white lime-
stone speckled with minute grains of quartz, and containing water-
worn pebbles of quartz, quartzite, and quartz-porphyry. The arena-
ceous portion is confined to a depth of about 6 inches, but scattered
pebbles occur for some distance higher up, embedded in the ordinary
compact chalk, into which the former seems gradually to pass. In
- the adjacent quarry the chalk-rock is found to reach a thickness of
about 30 feet above the Triassic strata. |

At Sheve Gallion Carn (3 miles from the main summit of
Slieve Gallion) the Chalk is seen to rest directly on Carboniferous
sandstone. The lower part is a faint pink limestone dotted with a
few glauconitic grains, but containing numerous pebbles and frag-
ments of quartz. The officers of the Geological Survey regard this
bed as a connecting-link between the Chalk and Upper Greensand,
classing 1t with the former on account of the abundance of Chalk
fossils which it contains. So far as can be judged, this deposit must
be very similar in its fossil contents to that at Moneymore.

Benbradagh, Dungiven, and Keady Hill.

The White Chalk of these localities is particularly interesting, on
account of the character and abundance of the fauna that it contains.
1 One labelled thus in the Jermyn Street Museum appears to me to be

NN. Deslongchampsianus.
2 «Report Geol. Londonderry, etc.,’ Dublin, 1843, pp. 115-116.

Vol. 53.] © THE CRETACHOUS STRATA OF COUNTY ANTRIM. 567

The cephalopoda, gasteropoda, and small sea-urchins are especially
noticeable, while many species of polyzoa and foraminifera have
been obtained by Mr. Joseph Wright, from the interior of flints.
From Benbradagh we are able to record a large Pecten, Arca sp.,
Trochus sp., Baculites anceps, Lam., Hamites sp., and Anisoceras sp. ;
from Dungiven, Dianchora, casts of corals (possibly Trochosmilian),
Ammonites | Pachydiscus] Griffithu, Sharpe, A. [P.| Oldham, Sh.,
and Belemnitella mucronata, Schloth.; and from Keady, G‘alerites
vulgaris and Calliostoma. Dungiven is, moreover, rich in sea-
urchins (Hchinocorys scutatus, Leske, and Galerites abbreviatus,
Goldf.), Pleurotomarie, and pelecypoda, including Spondylus spinosus,
Sow., Ostrea vesicularis, Lam., and Pecten [Janira] quinquecostatus,
Sow., besides numerous dimyaria, which have been referred by the
officers of the Geological Survey to Nucula, Thetis, etc. Among
brachiopoda may be mentioned Rhynchonella limbata, Schloth., Rh.
plicatilis, Sow. (ordinary and octoplicata varieties), Terebratula
carnea, Sow., and T. semiglobosa, Sow.

The base of the Chalk near Boyd’s Mountain is said to be a com-
pact sandstone mottled with glauconitic particles.*

The main characteristics of the Peninsular Division are :—

1. The great development of pebble-conglomerates at the base of
the Chalk, which here rests directly on the older rocks.
These conditions are already suggested in the northern
portion of the Eastern Division.

2. The presence of well-marked Cretaceous beaches, haying a
rich fauna of gasteropoda and small sea-urchins.

3. The abundance of organisms in the lower strata of the White
Limestone, resembling in character those found in a similar
position in the Central Division.

(5) Tae Norruern Division.

(The Northern Coast of Co. Antrim and Rathlin I.)
Tircreven Burn.

An examination of this section made by Mr. Stewart and myself,
in the burn north of Ben Evenagh, proved very disappointing. The
Cretaceous rocks were displayed in the valley a little below the
junction of the two streams, the strata dipping at a high angle
(about 15°) up stream, or eastward. They consist in the upper part
of a nodular pink chalk dotted with glauconitic grains, passing
below into a more glauconitic limestone, containing Spondylus
spinosus, Sow., Belemnitella sp., worn Inocerami, and fragments of
Echinocorys and sponges, a fauna recalling in its character that of
the Spongiarian zone. Portlock also appears to have found evidence

* Mem. Geol. Sury. Irel. Expl. Sheet 12, p. 1

568 DR. W. FRASER HUME ON [Dec. 1897,

of the presence of the Glauconitic Sands with Exogyra levigata and
Janira quinquecostata, but these do not as yet appear to have been
obtained in place.

Downhill to White Park Bay.

Along the northern and north-eastern coasts of Antrim, from
Downhill, three stations east of Portrush, to White Park Bay,
the White Chalk is well displayed, the Lias underlying it uncon-
formably both at Portrush and White Park Bay. It is in this
region a very compact white limestone, with flint-layers at intervals
of about 4 feet. The fossils appear to be of the usual character.”
At one spot on the east side of White Park Bay Barrois was able
to make out the following succession :—

Feet.

1. White compact limestone with flints (Belemnitella mucronata
and Lchinocorys scutatus)

2. The same with Belemmnitella [ Actinocamax] quadrata ............

3. White limestone with three bands of flints (large Jnoceramus-
fragments and Hchinocorys gthbus) ......cecsccecsseceecnseseecscees 7

4, White limestone with flints, with Belemnitella [| Actinocamax]|

vera, Micraster sp., Marsupites ornatus, Bourgueticrinus ellip-
tzcus, ete.

Peer essere esseseseeasteetereseseorsesennses

SPCC ESET HC SEE EHH OEHEHHHEHE SLES ESHSESEEEHHESEEEE HS GEBESEESHEOD

Below this point the strata present no special features of interest.

My attention has also been called by Mr. W. W. Watts to the
pinkish marly conglomerate near Ballycastle quay ; but, although
examined by several members of the Geologists’ Association, it has
not up to the present yielded any conclusive results. The officers
of the Geological Survey appear to have found Terebratulina gracilis
in some abundance, but I have hitherto obtained the species in
Ireland only in specimens of the Spongiarian zone from Hillsport
(Islandmagee), sent me by Miss Thompson. —

The most noticeable points in the Northern Division are :—

1. The great thickness attained by the White Limestone, and the
presence in it of Marsupites.

2. The reappearance of several elements characteristic of the
Eastern Division, such as the Spongiarian layer and the
Inoceramus-beds.

3. The presence of Glauconitic Sands with Exogyra levigata.

Il. Caemicat anp Micro-MInERALOGICAL SECTIONS.

The second portion of this paper is devoted to a chemical and
microscopical examination of a series of typical rocks, selected from
the principal lithological or zonal divisions of the Irish Cretaceous,
the methods adopted being similar to those employed by me in

1 For lists see Barrois, ‘Recherches sur le Terrain Crétacé Supérieur de

Angleterre et de l’Irlande,’ Lille, 1876, p. 206, and Geol. Surv. Irel. Mem.

Expl. Sheets 7 & 8, pp. 45, 46.

—

I.—ComPaRATIVE

[To face p. 568.

Classification of
Barrols.

Belemnitella mucro-

nata == White
Limestone with
flints.

ular Division. | Northern Division. England.

White Chalk of

Trimmingham.

White Limestone
with flints 100 feet +
thick, with
Eichinocorys ovatus
at base.

e Limestone

ints. Cephalo-

a, etc., very
on at base.

White Limestone,
with large flints
above.

Quart. Journ. Geol. Soc. Vol, LILI.

T.—Oomuraratryn Tatre or Zowat anv Drvistonat Cxasstrication (CRETACEOUS Sorata or County ANTRIM).

Peninsular Division,

White Limest )
with flints, Casinos with flints 100 feet +

poda, ete., very
common at base,

———

Conglomeratic heds
with gasteropoda,

Triassic, Carboni-
ferous, and older

ices Zonal Classification Classification of Classification cat ie =
Division. Zone. of Tate. Barrois. Gon einaaie es Southern Division. Central Division. Pastern Division.
i b
a
sien Upper part of White
Maestrichtien. THAnSSEOLeS LP Once ecto wale ceceint, ell © es sceeescrsie Wy teeny ee Meena | Re Score ae RN
\ White Limestone =
P : i ‘ with regular layers hite Limestone
diene |i [ee me | tometer
Ma Zi £ Amn é ata = 1 peers mucronata with reeular layers hick; rich fauna int.
mucronata. gollevillensis. | Pimestone with = Belem teas = White Limestone | of flint, 40 feat. at base. ~In some
Spongiarian Zone. ints, =o Sar with flints. places the Mulatto | Large ammonites at
Stone occurs at the base.
Mulatto base of this zone.
Belemnitella 3 : Not specially recog- || Nodular Chalk, zone Stone. Nodular Chalk with .
[Actinocamax] ey eae Not recognized. nized. ‘Tabular || of Belemnitella| Acti- 'Priassic Mar 3 ae eae (Acti- Neue tecognized! as
SeRONEAN quadrata. a flint at base. nocumaa’ quadrata, |~ "S13 als below. nocamaw) quadrata. LINE ADEE
OY Belemnitella Whi : cee Suonsiininny?
. hite Limes ssupites tae ale Spongiarian zone Spongiarian Zone
lias Chae [Actinocamax] wera Absent. aah uesone a Bais Ho Spongiarian zone. with ig a BN TTATICL with TEL tlcnauprioliite
‘ or Marsupites. : sa 3 [Actinocamac] vera. | [Actinocamax| vera.
Mioraste CS eon
cor-anguinwn. Do. Not represented. aie G
Zone of Hehinocorys 4 Behinocorys gibbus
Zone gibbus and Camerospongia.
of Micrasters. and 3 ‘ 2
Chloritic Chalk. Tnoceramus-zone, Perebratila, canned
aan eae Een
Micraster_ - We meunpors andy Not represented. bands numerous ;
cor-testudinarium. 0. iy acne Tnoceramus-20ne Spondylus spinosus
Sa absent. throughout; Ostrea
semiplana; Rhyn-
bite chonella-band.
hal
Rock. ~ 3s = = ie ee
ZL ane eet Lowest part of pre-
Holaster planus. Do. On of Anoceramus \) vious zone may Not represented. | Micraster breviporus.
veSR es belong here.
——|—__—_______||Chloritic Sands and)
TURONIAN Sandstone, =|
im Terebratulina D Unconformity.
gracilis. eh Zone of Ostrea :
Mippre Crarx. columba. Part of the Brogyra Callianassa-beds and | Part of the yellow-
columba- yellow greensands green sands with
Tnoceramus labiatus zone may belong here. with fish-teeth, and | Ostrea semiplana
or Rhynchonella the Hxogyra-columba| may belong to the
Cwieri. Do. band may belong here. | ‘Turonian.
hte be SORE Melbourn a : x
Rock. ae Sa) a 2 | Pee ee
Belemnites [Actino-) =| i a
cannace|ylariics iens| neat ns is

Ammonites {| Acantho-

Chloritic Sands and

carinata,

casper.

ceras] rofomagensis.| Sndstones.
CENOMANIAN
Huogyra Yellow Sandstones Zone of Holaster- Bxrogyra columba-
or es
columba and Grey Marls. subglobosus. zone (major part or
Lonmin Qeans. | Ammonites (Schlan- ernil whole).
hachia] varians.
Tnoceramus

Chloritic Marl. Crispi- Nodules possibly.
Weett mee chen i zone. pemees| Feet oy Par ee “i
Yellow Sandstones

Yellow Sandstones: Y £ Peot = zone of Ostrea

Pecten asper. =vone of Ostrea | Glauconitic Sands. Oe see caninata and zone

of Huogyra conica
in part,

Sands = zone of
Exogyra conica.

Major

portion of
Beogyra columba-
zone should he re-
ferred here.
Trigonia, Ostrea
carinata, and

Orbitolina at the
base.

Yellow-green sands:
with Bwroqyra
colunba and Cato-
pygus columbarius,

and Glauconitiec cal-
careous sandstone,
with Rhynchonella
Schlcenbachi.

Scattered brown
nodules.

Yellow Sandstone
with large Ostrea
carinata, Panopea

mandibula, ete.

Yellow Sandstone
with Pecten quadri-
costatus, Discoidea

subuecula, and
Micrabacia coronula.

Glauconitic Sands,
with Brogyra con-
ica, var. levigata,

Northern Division.

White Limestone

thick, with
Dehinocorys ovatus
at base,

Belemnitella
[Actinocamax] quad-
rata at base.

Flintless White
Limestone, with
Belemnitella
[ Actinocamax] vera,
Marsupites, and
Micrasters.

Glauconitic Lime-
stone, with Tnoce-
ramus-tragments.

[To face p. 568.

England.
: D

White Chalk of
Trimmingham,

White Limestone,
with large flints
above.

Chalk with flints.

Chalk often without

flints.

Chalk with one
flints.

Chalk with large
bands of flints;
Mieraster cor-testu-
dinarium abundant.
Nodular rock with

Not known.

Micraster breviporus,
or Holaster planus,
and chalk with same.

Soft white chalk, or
with marly bands,

and with Terebratu-

lina gracilis.

Increasingly nodular
chalk with Inocera-
mus labiatus.

Marls and limestones

plenus.

Grey Chalk with
large ammonites,
Nautili, and
Terebratule.

To.

Chalk Marl with
Ammonites varians
and Rhynchonella
Martini.

Do.

Do.

Bed with brown
“nodules.

with Belemnites |

Vol. 53.] . THE CRETACEOUS STRATA OF COUNTY ANTRIM. 569

studying the Cretaceous zones of the Isle of Wight and Folke-
stone,’

Many of the samples were obtained at Woodburn Glen, a locality
which has been especially referred to by both Tate and Barrois ;
while from Murlough Bay a series of specimens were selected
for the reasons mentioned on p. 565. I may recall that in Table II.
the ‘main residue’ consists of the fine clayey or siliceous materials,
the ‘ heavy residue’ being the organic and mineral contents which
remain after the clay has been removed by repeated washing and
decantation.

Glauconitic Sands. (Zone of EHxogyra conica.)
Woodburn Glen. (No. 7 in Table IT.)

The specimens obtained were of a deep-green colour, and con-
sisted mainly of glauconite and quartz-grains loosely cemented by
calcareous material. The samples were taken from the upper part
of the bed, consequently above the well-known fossil-band.

The original weight, after drying, = 77°59 grammes. After
solution in 20°/, hydrochloric acid there remained 58°66 grammes.
Heavy residue =75°6°/..

Total composition :—

Carbonate of lime ...... 24-4°/,
Heavy residue ............ (sce
100

The heavy residue was further subdivided into four divisions by
sifting, namely :—

A (coarse). Weight=°45 gramme, Mainly composed of quartz-
grains, the largest of which was a subangular fragment 3°5 mm.
long and 1°5 mm. broad. The great majority of these are water-
worn, and the larger ones are coloured green, pink, or yellow.
Although many of the grains show evidence of the presence
of crystal-faces, yet the angles are much worn down, and the
smaller ones, averaging 1 mm. in diameter, are beautifully rounded
and water-clear. A few small cleavage-fragments of red orthoclase
are also present, the largest being about 1 mm. square.

B (medium). ‘The greater proportion of this material consists of
glauconite-grains of a deep blue-green colour. Most of these are
undoubtedly the internal casts of foraminifera, the numerous lobes
into which they are divided indicating the multi-chambered
character of the genera which contdined them. The average size of
the better-defined examples is between ‘5 and 1 mm. As a rule
it is quite impossible to determine the forms generically, but these
may be differentiated into four types :-—

1. Rotaline types, which include all grains having the chamber-
casts rolled in a nautiloid manner, but with the earlier chambers
only visible on one side. These are very numerous.

1 See ‘Chemical and Micro-Mineralogical Researches on the Upper Cre-
taceous Zones of the South of England,’ London, 1893, pp. 11 & 12.

570 DR. W. FRASER HUME ON [ Dec. 1897,

2. Haplophragmioid or Cristellarian types, in which the casts
commence as spirally-convoluted chambers, the later chambers
becoming rectilinear, or in some cases slightly curved inward, giving
rise to crosier-like forms.

3. Globigerinoid types, the chambers being very globular in form,
and in general not presenting the symmetrical arrangement dis-
played in the previous varieties.

4, Tritaxian types, which are much more indefinite and tri-
angular in section, one of the edges being generally replaced by a
narrow flat plane.

5. Together with the above, there are a number of oval forms
having a depression running parallel to the major axis, which can
be explained only as being the internal casts of ostracod valves,
though any attempt at closer identification is impossible.

6. One beautiful cast of an undoubted Cristellaria was observed,
every chamber being clearly outlined, the general form being that
of Cr. gibba. It will be noticed that Textularian and Milioline types
are unrepresented, nor have any sponge-casts been observed.

The glauconitic material from this locality has been chemically
examined by Mr. A. P. Hoskins,’ and the general results are of some
interest. ‘The point on which he lays most stress is the relative
poverty in silica of the Woodburn specimens, the ascertained amount
(40°/, Si0,) being 10°/, less than the lowest percentage obtained by
Sipdcz in analyses of Challenger samples. The ferric oxide is
also 4°/, less than the mean, while the percentage of potash is nearly
double that found in the modern glauconite.

C. The lighter residue mainly consists of small quartz-grains
‘25 mm. in diameter.

D. The heavy-residue minerals, separated by means of cadmium
borotungstate (sp. gr. 2°9), are as follows :—

Rutile. This mineral occurs both as crystals and grains. The
crystals have a maximum length of -18 mm., breadth -07 mm., the
faces of the prism and pyramid being well developed. Their
pleochroism is deep yellow to straw-yellow, and they possess a
prominent black border, due to their high refractive index. The
enclosures are numerous, and have in most cases irregular outlines.
In one crystal the central portion polarized in a deep orange-red,
the outer part being bright golden yellow. Orange-yellow grains of
rutile are numerous, as also very rounded examples of zircon.
These are easily noticed on account of their high refractive index
and high order polarization-colours. A few well-marked crystals are
present, the largest having a length of -17 mm., with the prismatic
faces well developed and the pyramidal faces much reduced.

Muscovite is not uncommon, in thin silvery flakes, which, owing
to their extreme tenuity, do not display the high colours familiar
in the same mineral when examined under crossed nicols in rock-
sections. In nearly all cases they are seen to be of hexagonal
outline, being viewed at right angles to the basal plane.

Biotite is also present in brown scales, which practically display

1 Proc. Belfast Nat. Field Club, 1894-95, pp. 1-2.

lof

Wok 53: | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 571

no pleochroism, but, like the muscovite, are easily recognized by
their glitter, especially when the residue is being washed in
water.

Tourmaline is very rare, and when it occurs is in the pris-
matic forms with which we shall have to deal more fully in the
higher zones.

The principal points of note in the above zone are :—

1. The abundance and large size of the glauconite-grains.

2. Their derivation in all cases as casts of the internal chambers
of foraminifera, etc.

3. The extreme rounding of the grains of quartz.

4, The presence of muscovite and biotite, rutile, and zircon
(the latter more usually rounded), and the rarity of tourmaline.

Glauconitic Marls.
Woodburn Glen. (No. 6 in Table IT.)

The rock is a blue-grey marl, dotted with glauconitic grains.

The original weight, after drying, = 80°63 grammes, After
solution in 20°/, hydrochloric acid, there remained 29-18 grammes
of residue =36°19°/,. Total composition :—

Carbonate am linge, C602 2 ....6.5--sseseseans 63°91 °/,

Sandy Clay=sase... 2-5-0. —— Leta) fess == 2210 of

Heavy residue ......... == 108555) = 2000/4
100

The main residue consisted essentially of a dark blue siliceous -
clay, containing minute flakes of mica and spheres of iron pyrites.

The heavy residue chiefly contained grains of glauconite, many
of which show clear traces of their origin as organic casts. Most
of these are Globigerinoid or Rotaline in form, one-, three-, or five-
chambered aggregates being frequently noticed. The remainder is,
mainly composed of quartz-grains, the larger ones perfectly rounded
and colourless, or else subangular and even highly angular; while
the finer residue consists almost entirely of quartzose angular
particles and flakes of silvery muscovite.

By means of heavy liquid the following minerals were obtained :—

Tourmaline. Crystals of this mineral are abundant, the
hexagonal prism and rhombohedral terminations being well
developed. The length varies from 048 to -161 mm., and the
breadth from ‘029 to (068 mm. The colour is usually yellow-
brown to purple-brown, minute dark enclosures also being very
abundant. The absorption is, as usual, very strong, with O>E,
and in the smaller examples the polarization-colours are high, of
delicate pink and blue tints. A few fragments are also present.

Rutile occurs in red and deep yellow-brown rods (maximum
length 165 mm., breadth ‘03 mm.) and light yellow irregular frag-
ments. One of the crystals is beautifully zoned and twinned, giving
rise to the familiar knee-shaped combination. In one of the larger
yellow masses numerous enclosures of ellipsoid, rod-like, and
irregular character are visible.

o72 DR. W. FRASER HUME ON [ Dec. 1897,

Zircon is present in very rounded grains, many of which are
distinctly zoned. Maximum length 056 mm., breadth -026 mm,

[ron Pyrites is abundant in rods, rounded. aggregates, and
thin films, and limonite is also not uncommon.

As previously mentioned, flakes of silvery muscovite and
brown biotite are numerous, in addition to green micaceous films
of chlorite.

Garnet. A very transparent mineral, having perfect crystalline
form (rhombic dodecahedron) and quite isotropic, agrees in its
characters with the crystals which have been definitely determined
in the next zone.

Kyanite. A rectangular block with feebly-developed pinacoidal
cleavages at 90°, polarizing in low grey tints and having an ex-
tinction angle of 30°, is evidently an example of this mineral.

As in the previous cases, opaque white and dull brown adamantine
grains are numerous, but their true nature has not been determined.

A second experiment carried out on 42°45 grammes of material
yielded :

Carbonate of lime............... TOo2 cf,
eSIGLUE Nea Aiera nti eiatest ioe 29°68 °/,
100

While the marl was dissolving a delicate foraminifer was
obtained, which Mr. Chapman has identified as Plabellina cordata,
Reuss, a representative of the Nodosarininze most commonly present
in the Cenomanian. Further washing of the marl for foraminifera
yielded no further results.

Compared with the previous zone, the Glauconitic Marls show :—

1. A diminution in the size and quantity of the glauconitic
grains.
. 2. An increase in the calcareous constituents.

3. An increase in the amount and variety of the contained
detrital minerals, accompanied by a diminution in their size.

4. An abundance of tourmaline, particularly in the crystal form.

Especially characteristic of these marls is :—

5. The abundance and variety in form of iron pyrites.

While we may further note :—

6. The presence of kyanite and garnet.

Grey Marls or Yellow Sandstone.
Woodburn Glen. (No. 4 ain Table II.)

The weight of material employed in the analysis was 83°74
grammes. After solution in acid the insoluble residue yielded :—

CaCO, ascerccsenre 45°22 °
Clay ee ececccccrercascee 36 88 grs. or { Clay 5 it be Cuemit 44-04 of)
Heavy residue 8:99 ,, = Heavy residue...... 10:73 °/,
45°87 99:99

The main residue consists chiefly of finely-divided clay and
minute quartz-grains.

Vol. 53.] | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 573

The heavy residue was divided by sifting into four parts :—

A. Exceeding 1 mm. in diameter=‘33 gramme; this is composed
almost entirely of water-clear rounded grains of quartz. But some
which are green-tinted, due to thin films of chlorite, are more
angular in character.

B. -345 gramme is formed of quartz- and glauconite-grains in
about equal proportions, these having an average diameter of ‘5mm.
The quartz is, in the main, rounded and transparent. A few
silicified Jnoceramus-prisms are also present, together with red and
black fragments whose nature has not been determined. The
glauconitic grains show distinct evidence of alteration to a lighter
yellow-green product, only the darker green forms retaining their
organic outline.

C. The finest portion of the residue (8°18 grammes) consists of
minute angular grains of quartz,some of them almost rod-like in
character, flakes of mica, well-crystallized blocks of iron pyrites,
and green glauconite-grains. |

D. The heaviest residue, obtained by the use of heavy liquids,
though not abundant, was interesting. The minerals, in order of
note, are as follows :—

Iron Pyrites or Marcasite. It is practically impossible to
distinguish between these two forms of iron sulphide, though the
silvery white aggregations more probably contain a larger proportion
of the latter, and the brass-yellow cubic crystals may be safely
referred to the former.

Tourmaline. Crystals of this mineral are fairly abundant,
the rhombohedral faces being well-marked at one extremity, while
the other end is irregularly outlined or flat, having apparently
suffered fracture.

Zircon. Fragments of this mineral are numerous, but distinct
erystals are few and these also rarely show zoning.

Rutile occurs in orange-yellow irregularly-shaped grains, no
crystals being noted.

Anatase. This is, so far as I am aware, the first record of this
mineral in the Cretaceous of these islands. The crystal is of a blue
colour, changing to pale golden yellow. The pyramidal form is
clearly shown at one extremity, but the other end has been cleaved
parallel to the basal plane. The lustre is adamantine, and the length
=°046 mm.

Chlorite is present in thin micaceous films.

This zone differs from the preceding by :—

1. The greater abundance of detrital materials.
2. The reduction in amount of glauconite.

3. The presence of anatase.

Yellow Sandstone. (Zone of Ostrea carinata.)
Hillsport, Islandmagee. (No. 5a in Table II.)

The specimens obtained were of a light yellow colour, and
apparently consisted of quartz-grains with a slight admixture of
glauconite.

574 DR. W. FRASER HUME ON [Dee.Se75

The original weight after drying =41°39 grammes. After soution
in 20°/, hydrochloric acid there remained 24°6 grammes = 59-4/,,, or
total percentage composition :—

Carbonate of lime ...............00. 406 °/,.
RESO se 0.) .Sscnenactene teanmer eect 59°4°/,
100

The residue consists mainly of sand-grains, very minute glauconitic
casts, fragments of opal showing traces of organic structure, and
abundant thin flakes of muscovite exhibiting iridescent tints. In
addition the following minerals were observed: rutile, no definite
crystals, but red and orange-yellow fragments; zircon, both in
well-terminated erystals and rounded grains, ‘085 mm. in diameter ;
tourmaline, generally showing perfect prismatic outline and good
rhombohedral terminations ; biotite in thin brown cleavage-flakes.

A green mineral showing strong cleavage parallel to the vertical
axes with occasional cross cleavages at 90°, having straight
extinction, fair polarization-colours, and no apparent pleochroism,
most resembles enstatite in its appearance and characters.

A dull black mineral occurring in rounded botryoidal fragments
is also present, often displaying a bluish tint. When tested in
borax and sodium-carbonate beads in the reducing flame, no
evidence of manganese or iron was obtained. At present, therefore,
its true nature must remain uncertain, although both limonite
and psilomelane have suggested themselves.

Yellowish brittle masses are also present, of less hardness than
glass, but not as yet further recognized.

Yellow Sandstone.
Colin Glen. (No. 5 in Table II.)

Forty grammes of the rock yielded 25:3 grammes of residue
= 63:25°/,, that is :—

Carbonate of lime ..............+ 36°75 °/,
ROSIE ec pem et -usbesinbnaeabiceohe 63°25 °/,
100

The residue consists mainly of small quartz-grains less than
‘25 mm. in diameter, thin flakes of muscovite, tourmaline in
beautifully-preserved crystals (showing hexagonal prisms terminated
by rhombohedral faces), rutile in deep red, more or less rounded
grains, and rounded examples of zircon.

The rock differs from that previously described in not con-
taining any glauconitic casts, and both the Yellow Sandstones are
lacking in iron pyrites, therein differing from the Grey Marls of
Woodburn.

Enclosure in Grey Marls.

Woodburn Glen. (No. 4 in Table IT.)
Of the enclosed calcareous sandstone 79:97 grammes was dis-

solved in 20°/, hydrochloric acid, yielding 49°84 grammes of residue,
almost the whole of which can be classed as heavy.

Vol. 53.] | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 575

Total percentage composition :—

Carbonate Gf Lime. 10.6 .6..-s02.504-e0s 20 37°68 °/,

Glalye Chee eet vse etnen oe eaaes aces 1:86 °/,

(Heavy Tesidue \osc.9dosbeestwatdessadece 60°46 °/,.
100

The largest fragment is a block of quartz, coloured green by thin
chloritic films, 4 mm. in length and 3°5 mm.in breadth. There are
also yellow grains of the same mineral (2 mm. in greatest diameter),
most of the water-clear type having an average size of 1°5 mm.
While the majority are extremely rounded, it should be noted that
those having a green tint are in almost all cases distinctly sub-
angular. Glauconite is also present, showing traces of organic
structure. A few cleavage-flakes of red orthoclase also occur. The
greater part of the residue consists, therefore, of beautifully rounded
quartz- and glauconite-grains.

In a heavy liquid having a specific gravity of over 3°34, a large
crop of minerals was obtained, including —

1. Rounded transparent dark-bordered zircons.

2. Deep red and light yellow grains of rutile.

3. Beautifully perfect crystals (rhombic dodecahedra) of garnet
of a pink to red colour, remaining entirely isotropic under crossed
nicols.

4, Crystallized iron pyrites.

5. Kyanite is also present in some quantity, having the same
characters as the mineral described under the Glauconitic Marls
(p. 572).

In the lighter residue occur large crystals of tourmaline and
green flakes of chlorite.

It will thus be seen that these enclosed fragments are particularly
distinguished by the abundance of their detrital residue, the
minerals noticed being quartz, orthoclase, zircon, rutile, tourmaline,
garnet, kyanite, iron pyrites, glauconite, and chlorite. In the
presence of garnet and kyanite this grit resembles the Glauco-
nitic Marls rather than the Yellow Marls in which it is enclosed.

Inoceramus-band. (Zone of Inoceramus Crispi, Tate.)
Woodburn Glen. (No. 3 in Table IT.)
After solution 81°42 grammes yielded 27-34 grammes of insoluble

material, 25:97 of which may be called heavy residue.
f-Total composition :—

Carbonate ob lite ciiss.s.scocce store see nncsc ess 66°42 °/,

Olay ..2ee. ccd b at, peeaedeeee =vVicorver, =' 168°,

Heavy residue ..........essesees = 2597 , = 31:90%,
100

The residue, above 1 mm. in diameter, consists in the main of
angular and rounded fragments of quartz- and glauconite-grains,
These occasionally show their origin as organic casts, and have a

576 DR. W. FRASER HUME ON [ Dec. 1897,

deep green colour, but in most cases are altering to a light green
variety.

The quartz-grains are usually translucent, the largest being
4-5 mm. long and 3 mm. broad, and are at the same time coloured
green by films of chlorite. The water-clear examples are far more
rounded than those which are coloured, but some still retain angular
outlines. There are also loose aggregates of quartz and glauconite,
probably formed im situ. We may thus divide the coarser detrital
materials into three parts : —

(a) Quartz derived from schists, ete., usually coloured and subangular.

(0) Quartz-grains which are water-clear, transparent, generally highly
rounded, and probably derived from clastic rocks.

(c) Loose friable aggregates of quartz and glauconite, presumably formed in
place.

In this zone first appear delicate meshes of Hexactinellid sponges:
replaced in glauconite, though unfortunately most of them break up
very readily. One of these, which was somewhat better preserved
than others, has been examined by Dr. G. J. Hinde, who informs
me that from so small a piece it is impossible to state the genus to
which it belonged, though it may not improbably be a mesh of
Plocoscyphia.

The finer residue is composed of glauconite and angular grains
of quartz, together with many thin flakes of silvery white mica.
The glauconite is frequently in the form of green rods, these being
portions of the spicular meshes previously mentioned.

A number of heavy minerals were obtained by the use of boro-
tungstate of cadmium (sp. gr. 2°93), these including :—

Zircon, frequently well preserved, showing combinations of
the prism and pyramid of opposite orders. One was identical in
form with Dana’s type 5 with elongated axis.! Beautifully rounded
grains are also numerous,

Rutile in deep crimson and orange-yellow fragments.

Tourmaline, both in black columnar (schorl) and grey-brown
crystals. ,

Garnet of a distinct pink colour, in perfectly formed rhombic
dodecahedra.

Kyanite, showing two cleavages at 90°, low polarization-colours,
and extinction at about 30°.

Pyrites is present as small spheres of brassy-metallic lustre,
also in combinations of cubic crystals, while rod-like silvery white
ageregates must probably be referred to marcasite. A Teatularia
globulosa was observed completely replaced in pyrites.

Limonite is very abundant in dull-red amorphous masses.

Muscovite is common in the lighter washings.

For interprismatic silicification of Inoceramus, see p. 556.

This zone markedly differs from the preceding in:
1. The great increase in the calcareous constituents.
2. The presence of glauconitic sponge-meshes.

1 «System of Mineralogy,’ 6th ed. (1892) p. 483.

kag

vy

Vol. 53.] THE CRETACEOUS STRATA OF COUNTY ANTRIM. 577

Chloritic Chalk (Spongiarian Zone).
Woodburn Glen. (No. 2 in Table IT.)
After solution 80-66 grammes yielded 4:88 grammes of insoluble

material, 3°96 of which may be classed as heavy residue.
Total composition :—

CarhHonabeOn MimMetercer ee Reandenaeh as catses- cease ses 93°95 °/,

Olay Totes ud ssaanemtens amaaseset = =e ere ne eo

Fleavy residue. --.ccccasecaca- —leoovers. == 4910/7
100

The residue exceeding °5 mm. in diameter consisted of angular
colourless flakes of quartz, and a great abundance of glauconitic
grains, most of which are changing to a yellowish or reddish
alteration-product, having a limonitic aspect. A special feature is
the perfect preservation of many of the casts, the nature of the
foraminifera being easily determinable, while spicular meshes are
also conspicuous. A few delicate white siliceous tests of forami-
nifera are also present.

Mr. Chapman has been able to identity the following species
from these well-preserved glauconitic casts, and the remarks attached
are his :—

Textularia globulosa, Khr. ......... Internal casts, frequent.

EN OIGE PSs NVCUSS) Peace sense des oesas One example of an internal cast.
Verneuilina triquetra (Minst.) ... An external cast.

Tritaxia tricarinata, Reuss ......... Internal casts.

Bulimina Orbignyi, Reuss ......... An external cast.

Ep ChEGUNS, OED, eepeneseseede oceans * 3 5

B. Murchisoniana, dOrb. ...........- iy a -

xs OOUUSE, CO Ory, ea wie ieee aanione «ako of ES

Be UaTIabilis. MA ONO ies. avse< scewdenes 3 Be A

Globigerina bulloides, VOrb.......... 3 a a

Gl. equilateralis, Brady .........++. ss is An

? Discorbina rosacea (d’Orb.) ...... An internal cast.
Anomalina ammonoides (Reuss) ... External casts.

? A. grosserugosa (Giimbel) ......... External and internal casts.

Truncatulina Ungeriana (d’Orb.).. Internal casts.

For further notes on these casts, see p. 581.

In the finer residue, angular transparent quartz, glauconitic
spicular meshes, fragments of silicified foraminifera, and hexagonal
flakes of muscovite are numerous. The glauconite-grains and
quartz are often coated with a layer of red-brown limonite.
In general the former do not show much trace of their organic origin,
except in the case of the green rods (casts of spicular axial canals
presumably), which are relatively most abundant in the finest
portion of the residue.

Heavy minerals are less marked than in previous cases, though
zircon, in colourless grains; rutile, in large yellow grains (no deep
red varieties being noted) ; tourmaline, fairly abundant and in good
crystals; garnet, in small pink rhombic dodecahedra and larger
flat fragments; felspar, undergoing kaolinization; and chlorite,
in blue-green flakes, have been noticed.

Q.J.G.8. No, 212. 2@

578 DR. W. FRASER HUME ON [Dec. 1897,

The principal points of interest in this zone are :—
1. The predominance of calcareous constituents.
2. The angularity of the quartz-grains.
3. The abundance and good preservation of glauconitic casts of
foraminifera and sponge-meshes.
4, The diminution in the quantity and size of the heavy
minerals, with the exception of tourmaline.

White Limestone. (Zone of Belemnitella mucronata.)
Woodburn Glen. (No. 1 6 in Table IT.)

Of this white chalk 82:4 grammes was dissolved in 20 °/, hydro-
chloric acid, yielding 505 gramme of clay, and ‘015 gramme of heavy
residue.

Total percentage composition :—

Carbonate ot lime .........+20-<0. + 99°379 °/,

Clee RChe. ge. stnccem nines ser cinspaiice 613 °/,

Peavy esidite se. cesn-cs.scecsses ‘0182 °/,
100

The heavy residue consists of a few small angular quartz-grains,
two or three flakes of muscovite, and limonite.

Same Zone, Divis Hill. (No. 1 in Table II.)

After solution as above 81°42 grammes yielded ‘547 gramme of
clayey material, and 0042 gramme of heavy residue, the latter
consisting almost entirely of limonite, with one or two quartz-grains
(probably wind-blown).

Total percentage composition :—

Carbonate of lime’ ......5......000-- 99:323 °/,

Clay ieitrnpcccneces acute: RERBACER OLE ‘O12 fs

Heavy PESIGUG: onc. ,cresccccsaresvaeses 005 °/o
100

Same Zone, Magheramorne. (No. 1 a in Table II.)

On analysis 80°6 grammes yielded ‘394 gramme of insoluble clay,
silica, etc., and ‘0327 gramme of heavy residue, giving

Carbonate or limenmimnreee sss ieee 99°47 Jo

HITS TESLUC: (Ph -0..e eee ee kee eee 488 °/,

tleavy residue \.cea.deeorteeuneeceseneee see 041 °/o
100

The main residue consists of a thin, flaky brown clay, while the
heavy residue is in greater quantity than is usual with chalks from
the Belemnitella mucronata-zone. This excess is due, in some degree,
to the presence of large silicified fragments of organisms; but the
alteration has proceeded too far for us to be able to identify the

Vol. 53.] | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 579

original nature of the test thus altered. Apart from these fragments,
the detrital minerals are more numerous than in the other cases
analysed, quartz-grains being abundant. These are mostly very
angular, and are either colourless or coloured yellow by ferruginous
coatings. In addition to these, zircon-crystals and tourmaline have
been noted, though these are very rare. Glauconite-grains are also
present, and show clearly that they have originated as the internal
casts of foraminifera.

Speaking generally, the Belemnitella mucronata-zone is distin-
guished by the absence of detrital minerals. |

The reasons guiding the selection of the following specimens
obtained at Murlough Bay have been stated on p. 565.

Pebble-Conglomerate. (No. 12 in Table IT.)

The specimens obtained consisted of a pink limestone, spotted
with glauconitic grains, and enclosing rounded and subangular
pebbles of quartzite and vein-quartz. The analysis is that of the
chalk itself, the pebbles having been previously removed.

The original weight after drying =53°67 grammes. After solution
in 20°/, hydrochloric acid, there remained: Clay, etc. =2°22 grammes;
heavy residue=38'56 grammes.

Total percentage composition :—

Carbonate of lime ...........-...++ 28°16 °/o

ays Chee snistne teen cascvutalbes etme 4°14°/,

Heavy, Reside eed 0ok en i enka seni 67°70 °/o
100

The main residue calls for little comment, consisting only of fine
clayey material, enclosing minute grains of quartz and glauconite.

The heavy residue has been further subdivided, by means of
sifting, into four parts :—
_ A (material that does not pass through a sieve with 30 meshes
to the inch), Mainly composed of pebbles of quartzite, some
altogether colourless, others coloured green owing to the presence
of a thin chloritic coating, yellow-green masses of glauconite showing
no traces of organic structure, red orthoclase-felspar, felspathic
micaceous sandstone, finely micaceous golden-yellow sand-rock, and
among the smaller examples colourless subangular grains of quartz.

B (not traversing a sieve of 60 meshes to the inch). In this
residue the glauconite has more definite outlines, but its organic
origin is very much obscured. Colourless and brown grains of
quartz, both rounded and angular, are abundant. In many cases
the glauconite-grains are distinctly tubular, having apparently been
the internal casts of sponge-spicules. The light yellow-green
glauconite-grains are clearly the first stages in the alteration of the
deep-green varieties, most of which are undoubted internal casts of
organisms. ‘The latter are often coated with a lighter layer, or,
if a dark-green grain be broken, it is often seen to have a distinct
whitish to yellow border, penetrating to some depth. A few
mica-flakes and silicified tests of foraminifera are also present.

292

580 DR. W. FRASER HUME ON ([Deekzse7-

C (not traversing a sieve of 120 meshes to the inch). Colourless
quartz-grains make up the greater part of this residue, the remainder
consisting almost entirely of dark-green and yellow-green glauconite,
the former showing the characteristic rounded outlines.

D. The finest material is composed of very fine grains of quartz
and glauconite, the former highly angular, and either colourless or
pale yellow. Mica-flakes are numerous. By means of heavy liquid
(cadmium borotungstate of sp. gr. 2°84), a large crop of heavy
minerals was obtained, including rutile, zircon, tourmaline, garnet,
and chlorite :—

1. Rutile.—In general this mineral shows no evidence of erystal-
line form, and is of an orange-yellow to a deep-red colour. While
twinning is not marked in most cases, I have obtained one of the
peculiar interlaced groups, consisting of a number of intergrown
twinned needles, to which De Saussure applied the name of
sagenite.

2. Zircon occurs in definite crystals of prismatic habit, the
pyramidal terminations being, to some extent, rounded. Colourless
grains are also not infrequent, the high refractive index and
polarization-colours rendering them easy of identification.

3. Garnet.—This mineral is present in the form of pink-coloured
fragments and perfectly formed crystals: the latter, owing to the
unequal development of the faces of the rhombic dodecahedron,
often appear to have a prismatic habit. Cleavage being wanting,
the fracture-surfaces are usually irregular, and both fragments and
crystals are, generally speaking, isotropic. Itis very common in the
residue.

4. Tourmaline.—A few crystals are present, showing the rhom-
bohedral terminations and characteristically strong absorption.

5. Chlorite occurs in green flakes, when perfect showing hexa-
gonal outlines, but not usually displaying strong pleochroism.

The most noticeable feature of this conglomerate is therefore
the abundance and variety of the detrital materials.

White Limestone immediately above the Conglomerate.
(No. 11 in Table II.)

This consisted of a white chalk in which a few pebbles of quartz
were embedded.

The original weight after drying =79°23 grammes. After solution
there remained 3°35 grammes of residue=4°24 °/,, or

Main residue (clay, etc.) ... = 182 gr. = 2:29°/,

Heavy residue: -;.....:l...:0.: = BG, ee ale

Carbonate Or line v.32. 528 sees settee tar hetmeneatter 95°17 °/o
100

The heavy residue was further subdivided into :—
(a) Silicitied Znoceramus-tests="140 gramme. These consist of
snow-white rectangular blocks, which show when fractured columnar

Vol. 53.] | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 581

arrangements, like the pillars in an ancient temple. Chalcedonifica-
tion has proceeded on an extensive scale, so that each pillar now
consists of colloid silica, which has assumed a beaded form, due to the
formation of minute stalactitic outgrowths of chalcedony. From
the results obtained at Woodburn, we are led to the conclusion that
this is but a further stage in the interprismatic silicification of the
shells of Znoceramus.

(6) One mm. in diameter and above=‘28 gramme. This includes
a pebble of quartz with chlorite in the interspaces, 5 mm. in diameter.
Most of the quartz-pebbles, which are numerous, are subangular,
only the smaller grains being truly round. Glauconitic masses are
numerous, but generally display no organic structure. In one case,
however, it is clear that the whole consists of a delicate sponge-
mesh of spicular casts still bound together, and further enclosed in
a matrix of glauconitic material. Fragments of biotite, by their
arrangement evidently relics of biotite-mica-schists, also occur.

(c) Residue over ‘5 mm. in diameter=°347 gramme. This consists
almost exclusively of colourless, angular, subangular, and rounded
quartz-grains, dark-green and yellow-green glauconitic casts (in
general having no recognizable form, though one distinct spicular
rod was observed), and fragments of silicified Znoceramus-prisms.

(d) Residue over-25mm.in diameter. Practically the same as ¢,
except that the quartz-grains are far more angular.

(e) Minute residue, about’22 gramme. ‘The organic casts are more
prominent than in the previous cases, the dark-green casts of the
sponge-spicules often showing expanded knobs. Beautiful yellow
casts of foraminifera, mostly in individual rounded cells, but some-
times exhibiting the whole structure in detail, are also preserved.
Mr. Chapman, having examined these together with those of the
Chloritic Chalk of Woodburn, has. kindly supplied me with the
following report :—

‘The glauconite-grains from the Chalk of the above localities are
characterized by a quasi-translucent appearance, which is in distinct
contrast to that of the glauconitic grains from some other sedimen-
tary deposits, such as the Nummulina-zone of. the Barton Series in
the Isle of Wight, or the glauconitic clay of the Gault of Copt
Point, near Folkestone.

‘Two kinds of casts are here present :—

‘ Firstly, those which have been moulded within the chambers of
the foraminifera. They reproduce most delicately all the minute
spaces within the shell, even to the stolon-passages. The colour of
these internal casts is usually found ranging from a dull yellow to
an apple-green.

‘Secondly, there are grains in which the external form of the
foraminiferal test is reproduced, and these usually have a less
definitely finished surface, although many are exactly comparable in
form with the original test. In point of fact, the casts selected »
exhibit so admirably all the superficial characters of the original
shells that there can be no hesitation in assigning to the majority
of the specimens their generic, and even specific, names.

582 DR. W. FRASER HUME ON [Dec. 1897,

‘Besides the glauconite-casts of the foraminifera mentioned in
the list below, there also occurred in the residues searched an
example of a Haplophragmiwm, of small size, but probably
H. latidorsatum, Bornemann, haying the original arenaceous
test :—

Textularia agglutinans, @Orb. ... An internal cast.
T* globulost, MINT, sos Gencswanenseoce =: Internal casts.
Verneuilina spinulosa, Reuss ...... 4: cast.

V. triquetra (Mimst.) ..............- * a
Globigerina cretacea, V’Orb. ......... “a casts.
Anomalina anvmonoides (Reuss) ... e eS
Truncatalina Ungeriana (d’Orb.).. a: cast.’

It will be seen from the above report that, unlike the Chloritic
Chalk of Woodburn, this limestone contains no external casts.
The heaviest minerals were separated by means of cadmium boro-
tungstate, and included deep-red fragments of rutile (not common),
numerous colourless crystals (showing pyramid and prism), and
rounded grains of zircon, grey-brown crystals and yellow-brown
rounded examples of tourmaline, green flakes of chlorite, and
amorphous red blocks of limonite. And here it may be well to
mention that in many cases topaz is probably present. This
mineral, owing to its comparatively low refractive index, may be
easily mistaken for quartz, unless it be in well-marked cleavage-
fragments. These do not, however, appear to be abundant. One
crystal of garnet is also present. The average length of the
prismatic minerals is -08 to -1 mm.

The principal differences between this and the previous residue
are :—

1. The sudden reduction in the amount of detrital minerals
present.

2. The increasing angularity of the quartz-grains.

3. The abundance of glauconitic internal casts of foraminifera,

Compared with the casts obtained from Woodburn, we have

4, The apparent absence of external casts.

Chalk, 6 feet above the Conglomerate.
(No. 10 in Table II.)

After solution in acid, 72°86 grammes of chalk yielded 2°250
grammes of residue=3:088 °/,, or a percentage composition of :—

Carbonate ob lime tebee meses. eeseeeee ener 96°91 °/,

Glaytete:: a2. JES cee =o kier: i= aZ Ose

Heavy residue ............ =A ee, PLUG
; 100

In the coarse heavy residue none of the grains exceed 1 mm.
in diameter; these consist mainly of rounded and rectangular
fragments of quartz, and irregular glauconitic aggregates. The

Vol. 53.] THE CRETACEOUS STRATA OF COUNTY ANTRIM. 583

finer residue is interesting from the abundance of glauconitic casts
of sponge-spicules. Scme of these are merely tapering rods, others
are expanded at one extremity, forming a flat or subdivided head,
separated from the main body by a constriction, and some are
also spindle-shaped. Most of these are of a deep-green colour,
therein contrasting with the yellow casts of the foraminifera.
Of these, rounded individual chambers are most numerous, but unions
of such are not uncommon, though the latter are not so well pre-
served as in the previous examples. Portions of a Textularian cast,
showing the alternating character of the chambers, and Globigerine
have been observed. Fragments of delicate silicified tests are also
present.
No heavy minerals were obtained by the use of heavy liquids.
The most noticeable features in this limestone are :—
1. Quartz-fragments less than 1 mm. in diameter.
2. The increasing abundance of sponge-spicule casts.
3. The absence of heavy minerals.

Chalk, 12 feet above the Conglomerate.
(No. 9 in Table IT.)

After solution in acid, 80-92 grammes of chalk yielded 1°675
gramme of residue=2:07°/,. The analysis therefore gives

@arbonatevomlinon: =. 2%o oes cos deewncke 97-93- °/5

Olay. ier ate ececs =e Domiee, == — 188. fe

Heavy residue ...... ia a= 7 TRO),
100

The residue above ‘5 mm. in diameter consisted almost entirely
of the siliceous meshes formed in the interspaces between the prisms
of Inoceramus-shells. . Viewed from the side, the delicate columns
are beautifully shown in the larger specimens, while in most
the replacing silica forms thin chalcedonic films, dividing up the
test into irregular networks. The chalcedony appears snow-white
on the upper and outer surfaces. An Ammodiscus incertus and
other organic bodies are present, replaced in snow-white chalcedony.
A few rounded and subangular grains of quartz were also observed,
and some solid white masses of doubtful origin, breaking with an
even fracture.

The finer residue consists mainly of films derived from Inocerami
as described above, numerous rounded yellow spheres, the casts of
individual foraminiferal chambers, in some cases united and then
displaying the original form of the organisms. Globigerina is the
most common genus, Textularian types not having been observed.
In addition, rods, the internal casts of sponge-spicules, are numerous,
but much smaller than those observed in previous cases. Deep-
green glauconitic grains, though noticed, were rare. The detrital
material is composed of small colourless angular grains of quartz,

584 DR. W. FRASER HUME ON [Dec. 1897,

shining flakes of muscovite, one fragment of black tourmaline (schorl),
and a wine-yellow rutile, exhibiting knee-shaped twinning.
Compared with previous experiments, we notice here :—
1. The abundant evidence of silicification.
2. The reduction in size of the sponge-spicules.

Chalk, 18 feet above the Conglomerate.
(No. 8 in Table II.)
After solution in acid, 80°84 grammes yielded *922 gramme of

residue=1'14 °/..
The analysis is therefore as follows :—

Carbonate Oh LMG 2. ..dcocss-cocne soecest VS'E6

Clay Veter caresses. = tO ier. = 03a,

Heavy residue ...... = (82 a=) WO
100

Of the latter -0225 gramme exceeding ‘5 mm. in diameter consists
almost exclusively of the thin siliceous fibrous films previously
described, one or two quartz-grains, numerous rods and masses
of limonite, extremely porous, and seen to be made up of minute
rounded grains. Some of these, when broken open, are seen to
possess a distinct labyrinthic structure, and in a few instances
fine fibres project across the hollow cavities. Silicified foraminifera
(one a much altered Ammodiscus), and ostracoda such as Paracypris,
are sparsely distributed.

In the finer residue the limonitic rods are very abundant, together
with minute glauconitic rods, the internal casts of sponge-spicules,
and numerous rounded spheres or complete casts of foraminifera
(especially of Rotaline and Globigerinoid types), im which each
individual chamber is still bound together by a stoloniferous
connexion.

The characteristic features of this residue are :—

1. The abundance of limonitic rods.
2. The great rarity of quartz and other detrital minerals.

This series gives a very complete account of the successive
changes in the history of the Peninsular Division. The con-
glomerate appears to represent a period of maximum denudation ;
but, subsequent to its formation, the evidence points to a gradual
and continuous deepening. This is marked by :—

(a) The gradual diminution in the size of the quartz-grains.

(b) The reduction in the number and size of the heavy minerals.

(c) The steady increase in the percentage of calcareous con-
stituents.

(d) The reduction in the size of the spicular casts.

(e) The diminution in the size of the foraminiferal casts.

(f) The increase in limonitic materials, in this respect agreeing
with the deeper-water chalks of the South-east of England.

or

a

|
|

tN THE IR1isH Upper CRETACEOUS STRATA.

|

|

Per cent. of |

(To face p. 584.

Per cent. of Per cent. roe
ie. | Heavy Residue. Total Residue. Soluble in acid. Locality.
0051 677 99°32 Divis Hill, near Belfast.
0406 529 99°47 Magheramorne.
0182 631 99°47 Woodburn Glen, near Carrickfergus.
491 | 6°05 93°95 Do. do.
31:9 | 83°58 66-42 Do. do.
60°46 62°32 37°68" Do. do.
| 10°78 54°78 45°22 Do. do.
SS | So ae et rae =e Ts |
| 63°25 | 63°25 36°75 | Colin Glen, near Belfast.
Ee eee: ae tee « 1 Le:
59°4 59°4 40°6 Hillsport, Islandmagee.
= | a
13°39 36°19 | 63°91 : ;
WAS tes 29°68 70°32 ‘Woodburn el
—— — a en
| 75°6 75°6 24:4 Do.
| E cee ae ae x
|
1014 1140 98°86 Murlough Bay, near Ballycastle.
1892 0: nn eee aa Do. do.
1016 3'088 96°91 Do. do.
-— ————— — a
1°940 4238 95°76 Do. do.
| aes? Se eee sae
| 67°71 71°846 28°15 Do. do.

Quart. Journ. Geol. Soc. Vol. LIT.

I1.—Tasie sHowine THE RELATIVE Amounts or Rustpun i(N THE Irish Urrer Creracnous Sata.

(Lo face p. 584.

low . 5 area Original Weight of Weight of | Total Weight | Per cent. o: Per cent. of Per cent. of | Per cent. 5
Number. | Zone or Division. Weight, | Main Residue. |Heavy Residue.| of Residue. | Main Residite. | Heavy Residue,| Total Residue. | Soluble in acid, Locality.
1. Balen 81-42 547 0042 5512 672 0051 677 99:32 Divis Hill, near Belfast.
la. Do. 806 *3938 0327 "4.265 489 0406 "529 99°47 Magheramorne.
1b. Do. 82°4 "B05 “015 520 613 0182 “631 99°47 Woodburn Glen, near Carrickfergus.
G Pink Chalk aaa fi i F . , ; ‘
2. i | 80°66 92 3:96 4:88 114 4:91 6:05 93:95 Do. do.
a | sees
3. Hnocenaiat 81:42 137 25:97 27°34 168 | 31:9 33°58 66:42 Do. do.
| a
| Gaap Me |
| rey Marl. ‘i | 1 r c 4 | Vy i *BQe
We Walle tesa cones 7997 | 1-49 | 4885 49:84 1:86 60°46 62:32 37°68 Do. do.
Grey Marl |
da. Macipinartiont 83°74 36:88 8:99 45:87 44-04 10°73 54:78 45:29 Do. do.
| | —
Bh aw 40 |Not separated.| 40 40 63:25 63°25 36°75 Colin Glen, near Belfast.
ba. Do. 41°39 Not separated. 41°39 AV 3G 6 9 Uh ewcrss-ee ee 694 694 406 Hillsport, Islandmagee.
‘ Glauconitic 80°63 18'30 10:80 29:18 22°70 13:39 36:19 63:91
6. Marl. Voy Ceara me Sop ell Taree SCH Tne id eget (cca 29°68 roa) || Woodbum\ Glen:
Glauconitic 7 ‘ . . fs
Ie Sande | 7759 58°66 BSi6Gi-™ wilh a 75:6 15'6 2474, Do.
alk 18 feet ab é % ; i : ; ; ;
cinoma Cees 8084 840 082 929 1039 4 | Mo | 9886 Murlough Bay, near Ballycastle.
| |
Chalk 12 feet above “ | ae sae: F E ‘ ‘
9. | Pebble Conglomerate. 80/92 1622 163 1675 1-881 1892 2:07 9793 Do. do:
Chalk 6 feet above . q 4 $ . , f r
10. Pebble Conglomerate. 72:86 151 740 9250 2-072 1-016 3:088 96:91 Do. do.
Chalk just above (i vee _ r r é : R
11. PSBRIECCoslomeraltet 79°23 1:82 1-538 3°358 2/292 1:940 4238 95°76 Do. do.
|
Pebble : : ‘ : ; ‘ ‘ 15
12. Gonclomerste! 5367 | Be 36:34 38°56 | 4137 67-71 71'846 28°15 Do. do.

;
'
:
i
f

a

Ce

A
aks <i
¥

ILLUSTRATING THE GENER

ENCLOSURE
IN UPPER PART
oF YELLOW
SANDSTONE.

——

Large grains
numerous and

rounded. |

Musco
wee sae nee abund
Black and
eee brown crjy.......
) numero
- Rounded grains Good cry
numerous. TReYHen an 7
Jeep-red and yellow, Deep-red

Perfect crystals
common. comm"

ed

Frequent.

Green films
common.

|
|
}

| Fairly abundant.

;

Cubic cr}

| Well crystallized.

[To face p. 584,

RLOUGH Bay CHALK.

yellow frag’*

CHALK 12 FEET |

| One twin of rutile.

miereis aberwre eS) I i Nathalie tet minis

Casts of sponge-
spicules and
foraminifera.

Sponge- and

Limonitic rods
abundant.

CHALK 18 FEET |

ABOVE. : ABOVE. |

| —— So

Small angular
grains. Very rare. |
|
_ | Chalcedonic films. | Cb#!cedonic films

| abundant.

foraminiferal casts.

|
|
|
|

wy

Quart. Journ. Geol. Soc, Vol. LIT.

II[.—Tasre IvLustRaTINe THE GENERAL DistripuTIoN oF THE MINERALS IN THD [RIsH CRETACEOUS Zonrs.

[Lo face p. 584,

WNOROURE ANALYSES or Murtover Bay Crank.
a Gravconitic | GLAUCONITIC YELLOW IN UPPER PART TnocEramus- Cuiorrrre WuitE = ae
MINERAL. = | = r
Sanps. | Marts. SANDSTONES. or YELLOW BAND. CHALE. LIMESTONE. Poa C
| SANDSTONE. BBB. HALK ABOVE CHALK 6 FEET Cuank 12PeET | Cuark 18 PEET
CoNGLOMERATE. Pes. Conan. ABOVE. ABOVE. ABOVE.
Abundant. Large . a a —| [pn
| - 2 Larger grains Large grains Larger grains .
Abundant. Large | grains rounded iy, Bee: pe eeteh ae uartz-grains rge pebbles @ e
Quartz. earns SR aare CTT RRIGH OSE, rounded, angular numerous and variable, rounded Q Paris Very rare. Taree papp . Subangular grains. | Rounded grains. Small angular Very rare.
= ; ones abundant. rounded. and subangular. aa grains.
H angular.
| | 3 ae
Other forms of | Small pieces of Chalcedonic Chalcedonic . . , Ch: .
Bi E s : . . alcedonic films
GHB eo eee opal abundant. replacements. raplacementat Chalcedonic films.| ........ Chalcedonic films. | Chaleedonic films. | Chaleedonic films. abrodents
Paes (eesoaere Sal)
Felspars. : 0: are Abundant Orthoclase ‘
Dp Orthoclase rare rthoclaserare. | —......... (iam), | er Randa nasmeswas = P| Maewce geet [teeters
he asl |
Muscoyite and Muscoyite and . . . .
4 seep nanas cay Muscovite very Muscovite Muscovite Muscovite and ee
Micas. ‘air B Very. Mu ‘ 2
erste bonis ly iguite:wery common. | abundant. abundant. biotite abundant, | Blotite abundant. Muscovite-flakes, | 00...
Pyroxenes and Enstatite possibly |
Amphibolosss ai) 9 Ge ty tee 9 Noe cecceseee presetite- Uonipre CVE ye “ebese gs Ceo ela Ce Siar Sheen | Me ee | |
——— i i ses} Be ar
™, . | Black and grey- Frequent in
Tourmaline. Crystals very vare. | Crystals numerous. | In good crystals. | brown erystals good exystals Very rare. A few crystals. {Rounded fragments.| One fragment.
numerous. H as
|
t | = | pee =
|
ane Rounded grains Rounded grains In crystals and Rounded grains Good crystals Grains present Waaraare Crystals and Numerous crystals |
5 numerous. numerous. rounded grains. numerous. frequent. | z y : grains common, and grains. [7h OY ERS? Se | eee nooo
|
ee es =!
Orange-yellow |
a Red and orange- A |
Rutile. pan aA RESTS yellow crystals and | Only in fragments. Western etl and yellow} : a cep rel) and | Large 9 ellow Ores valloke and} “Notcommon, | 0 jgeenne One twin of rutile.
| eep-red crystals yellow fragments. grains numerous. | yellow fragments. grains, deep-red grains. |
rare, Y |
Anatisereee cle ean. i ay, Oneverystali, off areas fi Suceegeeien I 2 adesseee SINR —R yeac) SI career om | mc ste | mn |
Perfect crystals Perfect crystals Good crystals
ceumets Rare 4 common. common. Smal icrystals and fragments. One crystal
UGG = cecrccee Rares geile teteenes Frequent: =~ aececiaee = [0 tease ls 2 Seer EU eet 4] ere reece tanning ge cen | |
|
Chlovite. Green flakes not Green films Green films Green flakes |

uncommon.

common.

common,

Glauconite.

Forming casts of

foraminifera and

ostracoda, Very
abundant.

| Abundant in the
form of casts.

Very minute
grains generally,

|

Blue-green flakes.

abundant.

Green flakes.

Fairly abundant.

|

Often as casts
of Hexactinellid
meshes.

Casts of sponges
and foraminifera
humerous,

Very rare.

Abundant in
irregular masses,

| Casts, abundant
| and perfect.

Limonite.

Common.

Very abundant.

Pyrite or
Marcasite.

Very abundant
in rods, films, and
spheres.

Well-crystallized
blocks numerous.

Well crystallized.

Cubic crystals
and aggregates.

Frequent.

Amorphous red
masses.

Irregular
aggregates and
casts of sponge-

Casts of sponge-
spicules and
foraminifera.

Sponge- and

Limonitic rods
abundant.

foraminiferal casts.

Mol: 53. | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 585

III. Conctusions As TO YHE SEQUENCE AND CoRRELATION OF THE
Irish Cretacreots STRATA.

We are now in a position to trace the probable sequence of events
in Ireland, comparing it with the established standards of the
English Cretaceous zones, and in doing so it will be well to commence
with the lowest division, the Glauconitic Sands.

Glauconitic Sands (Zone of Exogyra conica).

These beds, easily recognized by their deep-green colour, are
mainly restricted to the Eastern and Central Divisions, extending
from Larne to Colin Mountain, a little south of Colin Glen, a range
of over 25 miles, though Portlock’s record of their occurrence in
Tircreven Burn shows them to have been also present in the
Northern Division. In their southernmost exposure at Colin
Mountain they attain their maximum thickness of 16 feet, in all
other localities where they have been examined varying from 5 to
8 feet thick. These strata are remarkable for the uniformity of
their lithological character, being largely composed of glauconitic
(with an admixture of arenaceous) grains, and containing an abun-
dant fauna, especially in a central band. Exogyra levigata, Sow.,
is ubiquitous, being generally accompanied by Pecten [ Amussium]
orbicularis (Mant.), and P. | Janira] quinquecostatus, Sow.

In addition to the three species just enumerated, which are
common to both divisions, the following list shows the principal
fossils obtained in the greensands and their divisional distribution :—

CLASS. CENTRAL Division. HastTERN Division.
REPTILIA .........| Vertebre of Plesiosaurus.
PISCES ...............) Corax falcatus, Ag., Lamna | Lamna appendiculata (Ag.).
appendiculata (Ag.).
CEePHALoPoDA ...| Ammonites [Hoplites| catil- | Ammonites [Schlenbachia]
lus, Sow. (probably). varians, Sow., sp. (Tate).
Belemnites ultimus, d’Orb. | Belemnite foreshadowing Be-

lemnitella { Actinocamac |
vera (Mil.).

GAsTEROPODA ...| ? Littorina (numerous). ? Littorina.
PELECYPODA:
Dimyaria ......... Trigonia, sp. (mainly Colin | Avicula, near A. lineata,
Glen). Romer.

Arca {Cucullea| carinata,
Sow. Large casts of Cucul-
lea ligeriensis (d’Orb.) at
Squires Hill.

Casts of Thetis Sowerbyi (°?),
Rom. (large at Cave Hill).

Avicula, sp.
Monomyaria_ ...| As above. As above, and Pecten
Chlamys| Galliennei, P.
Chl.| asper, Lam.
RAO BTOP OIA... ri: oy nena Rhynchonella near Rh. Cuvi-

eri, Sow.
Terebratula squamosa, Mant.,
or T. biplicata, Sow.
Kingena lima, Detr.

586 DR. W. FRASER HUME ON [ Dee. 5807.9

In the foregoing list the most prominent species observed by
the present writer are mentioned, except where a name is attached,
indicating the authority for the occurrence.

Besides these the following species have been recognized :—

Exogyra conica, var. undata, Sow. ; large casts of Cucullea ligere-
ensis (d’Orb.), from Squires Hill (agreeing with casts obtained at
Vimoutiers) ; and Cyprina, of unrecognized species, from Squires Hill.

Mr. Jukes-Browne has examined a series of fossils from this
horizon, and the following notes are culled from his remarks and
suggestions :—‘ Of the Avicule there are three different species, one
of which resembles Avicula lineata, Romer; but, though there is a
resemblance, the figure shows a ridge on the anterior side which is
absent in the Irish specimen.

‘Of the pectens the fragment of the large coarse species is P. asper; |

the ribs become more separated with age. Another (probably that
referred to by Tate as P. Dutemplet) is nearer P. Gallienner,
d@’Orb., and agrees with those from Warminster identified by
me as G'alliennez. The smaller ones have no oblique striation and
are nearer to P. hispidus, Goldf. There is also a small Pecten allied
to P. divaricatus, Reuss.

‘The Rhynchonella seems to be Rh. Cuviert. It might be
Rh. Werstii of Davidson’s Supplement, but appears to agree better
with Rh. Cuviert. (This appears to be the species referred to by
Tate as Rh. nuctformis.) Some triangular single valves also occur,
which may be young individuals, of the triangular race of 2th. Man-
telliana as it occurs in Dorset.

‘The small Terebratule are not determinable; there is one which
may be 7. sguamosa, but also it may be a young diplicata. Some
have the shape of Kingena lima and are probably that shell.’

Respecting the age of these beds, Tate says:—‘The zone of
Exogyra conica represents the basement-beds of the Etage Céno-
manien of the French geologists, and is approximately equivalent
to the Greensand of Blackdown.’? Barrois remarks: ‘The glauconitic
zone with Ostrea conica, Pecten asper, Belemnites ultimus, and
Ammonites varians, corresponds almost certainly with the Ceno-
manian zone of Pecten asper, the Warminster Beds of England,
and the Holaster nodulosus-zone of M. Hébert. It strikingly
recalls, both in its fauna and petrographical characters, the zone
of the same name in the North-east of France.’* The fauna
above mentioned bears the closest resemblance to that of the
Upper Greensand in the West of England, almost every species
present in Ireland having also been recorded from the latter district.
But though the general relationships of the Glauconitic Sands are
thus easily determinable, the consideration of their position in the
classification of the Upper Cretaceous rocks involves a discussion of
nomenclature. Barrois,* following Hébert, placed the Upper Green-
sand at the base of the Cenomanian, regarding it as markedly
separate from the underlying Gault. A further study of these

1 Quart. Journ. Geol. Soc. vol. xxi. (1865) p. 33.

2 «Recherches sur le Terrain Orétacé Supérieur de Angleterre et de
l’Irlande,’ Lille, 1876, p. 213. §, Ibid. p. 7.

Vol. 53.] THE CRETACEOUS STRATA OF COUNTY ANTRIM. 587

two formations in the western counties of England has convinced
the majority of English students of Cretaceous geology that such
a separation is not justified by the evidence, which tends to prove
that they are different lithological conditions of the same division,
the greensands being more conspicuous in the western counties,
near the ancient coast-line, while the clays of the Gault predominate
to the east.

The results of these researches have also convinced these observers
that a true Cenomanian base-line, the Chloritic Marl, exists at the
summit of the greensands, characterized by a marked change in the
fauna and lithological conditions, and by the presence of fossils
derived from the underlying strata. The views thus briefly
summarized have been clearly set forth by Messrs. Jukes-Browne &
Hill,! whoehave also argued that the same statements are applicable
to the Cretaceous strata in the North of France. Believing that
these results have placed the classification on a secure basis, I am
of opinion that the Glauconitic Sands can no longer be retained as
Cenomanian, but must be placed in the combined Upper Greensand-
and-Gault division, for which sooner or later a convenient reference-
name will be required.

In attempting to correlate more precisely the English and Irish
greensands, the somewhat different character of the fauna in the
Central and Kastern Divisions must be kept constantly in mind, and
the non-recognition of these factors appears to be the cause of the
differences between the classifications published by Tate and
Barrois. For comparison, the subdivisions of the Upper Greensand
adopted are as follows :—

Devon and Wiltshire. Zones.
Warminster Beds...........-.-- Pecten asper.
Urrrer Grreensann 4 Devizes Beds............:...0200+ Ammonites | Schlen-
| Blackdown Beds (in part) ... | dachia] inflatus.

Though the retention of Pecten asper as the title of a zone is open to
objection, no species is sufficiently characteristic of this horizon to take its
place satisfactorily.

The main features in the Glauconitic Sands which should be
emphasized are :—

1. Exogyra laevigata, Pecten [Janira| quinquecostatus, and P.
[ Amussium | orbicularis are ubiquitous.

2. The Central Division is characterized by the great abundance
and large size of the dimyarian pelecypoda.

3. The Islandmagee area is, on the contrary, marked by an
absence of such pelecypoda, and by the abundance of the subgenus
Chlamys and small brachiopoda.

Speaking generally, the lithological character of the strata,
together with the presence and large size of Ewogyra laevigata and
Pecten orbicularis, find their nearest parallel in Bed 3 of Meyer,”
and Bed 7 of Downes,’ that is, high representatives of the Black-
down Series, or at the very base of the Upper Greensand; but the

* Quart. Journ. Geol. Soc. vol. lii. (1896) pp. 99-178; see especially

pp- 170-177. 2 Ibid. vol. xxx. (1874) p. 373.
2 Ibid. vol. xxxviii. (1882) p. 75, & vol. xli. (1885) p. 27.

588 DR. W. FRASER HUME ON [Dec. 1897,

majority of the mollusca present are most abundant in the Ammo-
nites inflatus-beds of the West of England—for example, Hoplites
catillus, Sow., Cucullea carinata, Sow., and the large dimyarian
bivalves. In the Central Division no member of a fauna character-
istically later than this zone (the zone of Ammonites inflatus of
Barrois) has been met with, but the brachiopoda and pectens
obtained in Islandmagee suggest the probability that Warminster
(Pecten asper-zone) conditions had already commenced in the deeper
waters of the Kastern Division.

In connexion with this latter supposition we have not ourselves
noted Ammonites [Schlenbachia| varians, recorded by Tate from
the latter district, but the pectens (subgenus Chlamys) obtained
were P. asper, Lam., P. Galliennei, @’Orb., and P. hispidus, Goldf.
Chlamys is therefore abundant, and these species are more common
in the Warminster than in the Devizes beds; it must also be
admitted that the Rhynchonelle and Terebratule accompanying
them usually occur in beds younger than the Ammonites inflatus-
zone. We conclude then that the Glauconitic Sands commenced
during the earlier period of the Ammonites inflatus-zone, and, owing
to their nearer proximity to a coast-line than the Devon Greensands,
they retain a strong admixture of the earlier Blackdown fauna,
though, in the deeper-water exposures, containing forms which, as
depression proceeded in England, became dominant in the upper
zone of the English greensand.

Murray and Renard* have given an account of the general mode
of formation of glauconite, pointing out that it is along high and
bold coasts, where no rivers enter the sea, and where accumulation
is apparently less rapid, that glauconite appears in its most typical
form and greatest abundance. ‘These deposits are also formed near
continental masses of land about the lower limits of wave-, tidal,
and current-action: that 1s, in the neighbourhood of Murray’s
mud-line, in the zone of maximum chemical activity.

The Irish rock is richer in glauconite than the typical examples
dredged by the Challenger Expedition, the nearest approach to it
being the dark greensand obtained by the U.S.8. Tuscarora. That
the deposit was formed near land seems certain from the great
numbers of the pelecypoda, their existence in colonies, and their
large size; the probability of a high coast-line is testified by the

abundance of glauconite, and comparatively small percentage of -

detrital minerals. The chemical action is evidenced by the fre-
quency of casts, especially among the dimyaria of the Central

Division. As these deposits do not continue to the north much

beyond Larne, and to the south disappear at Colin Mountain, it
would seem that the formation was laid down in an indentation of
the coast, the Central Division being nearest to the shore-line. A
fauna similar to that of the highest Blackdown Beds here found a
suitable home, and, so long as the conditions continued favourable,
flourished in a high degree, thus becoming contemporaneous with
species characteristic of higher zones in England, 4

1 Challenger Reports, ‘ Deep-Sea Deposits,’ p. 382,

Vol. 53.] THE CRETACEOUS STRATA OF COUNTY ANTRIM. 589

These organisms, however, seemingly disappeared before the
lithological conditions had undergone comp'ete change, and in the
Glauconitic Marls above a new fauna poor in species takes their place.
Vermicularie (V. quinquecarinata, Rom., and V. concava, Sow.)
are abundant, and large pectens are occasionally present, but these
are not sufficient to determine the exact stratigraphical position of
the marls. The evidence afforded by the chemical examinations
tends to show that a depression was taking place, and the con-
tinental slopes were being denuded, heavy minerals being more
abundant, and the calcareous element very pronounced. The
depression continuing, fine sands replace the clays, and the great
series of the Calcareous or Yellow Sandstones is deposited.

Yellow Sandstones (Zone of Ostrea carinata).

These beds have practically the same extension as the Glauconitic
Sands, but have not hitherto been recorded from the Northern
Division. They attain their maximum thickness of 30 feet in
Colin Glen, varying in the other localities examined from 4 to 20 feet
in thickness. These strata are very uniform in lithological character,
being mainly composed of extremely minute arenaceous grains, though
in the Eastern Division a clayey admixture is noticeable, and glauco-
nite is present in minute particles. Organic contents are, as a rule,
rare, but they are more abundant in the Eastern Division, the corals and
sea-urchins recorded from this horizon having been collected chiefly
in the Islandmagee localities. The distribution and nature of the
species present are as follows :—

CLass. CENTRAL Division. EAstTERN Division.
CEPHALOPODA ...... Aadeesiasaul Ammonites {Acanthoceras|
rotomagensis (in museum),
PELECYPODA: ‘ Detr., sp.
Dimyaria ............| Trigonia seabricula, Lye. Arca sp., Mytilus sp.
Avicula sp., Pinna sp. Avicula, sp.

Panopea mandibula, Sow.

Cucullea ligeriensis, d’Orb.,
sp. (Tate), in upper part.

Monomyaria ...... Pecten | Janira| quadricos- | Janira quadricostata (Sow.).
tatus (Sow.), lower part.

Pecten | J.| quinquecostatus, | Ostrea canaliculata, Sow.
Sow., & J. equicostata, | Plicatula inflata, Sow.
Lam. (in upper part).

Ostrea | Alectryonia| cari-
nata, Lam. (large).

Tima semisulcata, d’Orb., &

L. globata, Sow. (abundant).

BRACHIOPODA ...... Rhynchonella dimidiata, var. | Rhynchonella dimidiata, var.
convexra, Sow. convexa, Sow.
VERMES ............| Vermicularia quinquecari- | Ditrupa difformis, Lam.
nata, Rom., & V. concava,| Vermicularia quinquecari-
Sow. nata, Rom., & V. concava,
Sow.
EcHINODERMATA... wns vuaiee Discoidea subucula, Klein.

ACTINOZOA ......... dy 2 Micrabacia coronula, Goldf.

590 DR. W. FRASER HUME ON [ Dec. 1897,

In the Central Division these Yellow Sandstones pass insensibly
into the Chloritic Sandstones. Tate remarks:—‘ The zone of Ostrea
carinata represents most certainly a portion of the Upper Greensand
of England and the Lower Cenomanian of Normandy,’ a view
which, apart from the question of nomenclature previously raised,
agrees with our own. Barrois submitted ‘that the sandstones
with cherts containing Ostrea carinata, Micrabacia coronula, resting
on the zone of Pecten asper, and containing a Cenomanian fauna
without admixture, are naturally to be placed on a level with the
Holaster subglobosus-zone in England.’ The lithological character
of the Yellow Sandstones appears to resemble very closely that of
the sands with chert, as developed, for instance, at Warminster. The
large Pecten | Janira] quadricostatus agrees in all respects with those
occurring in the Warminster Beds, in which Lima semisulcata,
Janira quinquecostata, Vernicularia concava, and Discoidea subucula
have also been obtained.’ Ostrea carinata has also been recorded
from the chert-beds at Durdle Cove, Purbeck, by Barrois.? Sand-
stones with chert-beds of similar nature form Bed 5 of Meyer,’ of
which Janira quadricostata is a typical fossil. Indeed the suc-
cession at Colin Glen shows an interesting parallelism when compared
with Meyer’s Beds :—

The lowest Yellow Sandstone with cherts and J. quadricostata is Bal &
SNA GO) .deeanecens ness ede cteee walceastvescens corsonmeecaacvsteeeeeae eee

The middle Yellow Sandstone with large Ostree is similar to ...... Bed 7

The base of the Chloritic Sands with Orbitolina concava and Rhyn- Bed 8
chonella Schlenbacht 1s similar tO .....i0.+0~ «+ cm-coans=sae oe seerteeeeeee | .

The LHxogyra columba- and Callianassa-beds with polyzoa are | Bed 11
SIMA AP ALO: Gent bmctwiemcem, wala tuiewnichicesivs'ss-nhmnson oes mennepecne ane ee teen :

At Colin Glen the Yellow Sandstone corresponds nearly in its
fauna with Beds 5-7 of Meyer: that is, the upper portion of the
Devizes beds, or zone of Ammonites inflatus. In his Bed 10 occur
together some of the most characteristic of the fossils mentioned
above, including Ostrea [Alectryonia] carinata, Pecten | Janira]
quinquecostatus, Sow., Rhynchonella dimidiata, var. convexa, Sow.,
Lima semisulcata, d’Orb., and Discoidea subucula, Klein. It there-
fore appears probable that the Yellow Sandstones correspond as a
whole with Beds 5-10 of Meyer, and are mainly parallel with the
Warminster greensands, or Pecten asper-zone. We have not been
able to substantiate the presence of Holaster subglobosus, Leske,
but Ammonites [Acanthoceras| rotomagensis (Defr.) appears to —
have been found in this formation from Sallagh, a specimen of it
being present from this horizon in the Belfast Museum. There is |
therefore a possibility that the Cenomanian fauna was already —
foreshadowed in the Eastern Division.

We conclude that the Yellow Sandstones are mainly of War-
minster or Pecten asper-age, but that they still possess, in the
shallower-water Central Division, an admixture of the fauna of the

1 A. J. Jukes-Browne, Geol. Mag. 1896, p. 261.
2 «Recherches sur le Terrain Crétacé Supérieur, ete.,’ p. 92.
° Quart. Journ. Geol. Soc. vol. xxx. (1874) p. 373.

Vol. 53.] | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 591

lower A. znflatus-zone, while in the easternmost localities the true
Cenomanian conditions are foreshadowed, the corals and sea-urchins
also occurring only in the latter.

Chloritic Sands and Sandstones.

These beds present a difficult problem, the differences between
the Central and Eastern Divisions being extremely marked. (Wood-
burn Glen, in its characters and relations, must now be included in
the Eastern Division; in the previous cases it occupied an inter-
mediate position between the two types.)

Tate remarks:—‘The Chloritic Sands and Sandstones have, on
the whole, a fauna possessing an Upper Greensand facies, many
species, however, pointing to higher zones. It is very probable
that the Chloritic Sands of Woodburn (the zone of IJnoceramus
Crispi ?) may be inferior to the Chloritic Sandstones of Colin Glen,
the zone of Exogyra columba. These zones, however, never come
into contact.’

Barrois concludes that, as all the fossils obtained in these beds
were Turonian, these strata must be considered as belonging to that
stage, and refers them to the zones of Terebratulina gracilis and
Holaster planus.

The zone of Exogyra columba is characteristic of the Central, the
Inoceramus-zone of the Eastern district, and the former will be
first dealt with.

Central Division. (Zone of Exogyra columba.)

These sands and sandstones, often of a greenish-yellow colour,
are well developed in this Division, attaining a thickness of nearly
20 feet at Colin Glen. In the Eastern Division, however, they are
of rare occurrence, being represented by yellow-green sands 4 feet
thick at Barney’s Point, in Islandmagee, where the two zones
mentioned by Tate are in contact, andit is seen that the Hwogyra
columba is the lower of the two.

Gault has added a considerable number of species, which have
not come under our notice.’

As I have already remarked, Orbitolina concava and Rhyncho-
nella Schlenbachi characterize Bed 9 of Meyer (which he still
includes in the Upper Greensand), and the latter does not extend
beyond his Bed 12. Ostrea carinata, Lam., Pecten asper, Lam.,
Cucullea ligeriensis (VOrb.), Trigonia crenulata, Lam., Oxyrhina
Mantelli, Ag., Ptychodus decurrens, Ag., and Callianassa are
limited in the same manner in Devon, and most of these are
found only in Beds 10 and 11. Barrois also observed the Orbito-
lina- and Rhynchonella Schloeenbachi-beds in Devon, overlain by a
fauna in part similar to the above, accompanied by Ammonites
[-Acanthoceras] Mantelli (Sow.) and A. Couper (Brongn.), and
regarded them as of Warminster age.” It is therefore evident
that the Hwogyra columba-zone has a strong Lower Cenomanian

1 Proc. Belfast Nat. Field-Club, n. s. vol. i. (1877), p. 258.
2 «Recherches sur le Terrain Crétacé Supérieur, etc.,’ p. 70.

592 DR. W. FRASER HUME ON [Dec. 1897, :

CLASS. CENTRAL Division. EASTERN Division.
PISCES ...............| Oxyrhina Mantelli, Ag.,

Ptychodus latissimus, Ag.,
Pt.decurrens,Ag., Pt.mam-
millaris, Ag., Corax fal-
catus, Ag., Lamna sulcata,
Ag., Lamna appendicu-

lata (Ag.).
CEPHALOPODA ...... Ammonites [Pachydiscus]
lewesiensis, Mant. (Tate).
GASTEROPODA ...... Natica sp., and others un-
described. |
PELECYPODA: |
Dimyaria. «...i<. Trigonia crenulata, Lam.,

Tr. Dedalea, Park., Car-
dium gibbosum, Tate, Ana-
tina Royana (d’Orb.).

Monomyaria ...... Exogyra columba, Lam. | Exogyra columba, Lam.,
(large), Ostrea [Alectryo- | Ostrea semiplana, Sow., |
nia| carinata, Lam., O.| O. carinata, Lam., Pecten |
canaliculata, Sow., O.| [Janira] quinquecostatus, |

semiplana, Sow., Pecten | Sow.
[Chlamys] asper, Lam., P.
[Janira] quinquecostatus,

Sow., P. [Janira| equi-
costatus, Lam.

BRAcHIOPODA ......| Waldheimia hibernica, Tate. | Rhynchonella Schleenbachi,
Dav.

VERMES ............| Vermicularia concava, Sow. | Vermicularia concava, Sow.

CRUSTAGRAS cc ccca.: Callianassa sp.

EcCHINODERMATA . Se ey Eee Catopygus columbarius,
d’Orb.

FoRAMINIFERA ...| Patellina [ Orbitolina] con-

cava, Lam.

aspect. It is true that Ostrea semiplana, a common Turonian
fossil in England, has been recorded by both Tate and Barrois, and
I have obtained it at the very summit of the zone in Islandmagee,
but it is impossible at present to say whether the association at
this point is not due to the mixing of the two zones at the uncon-
formable junction.

The fishes above mentioned are also of common occurrence in
the Turonian strata, but they equally occur in the Cenomanian,
Ptychodus decurrens being especially frequent in the latter,

The view here set forth receives further support when the con-
ditions prevalent in France during Cenomanian time are specially
considered. Thus in the province of Maine is a thick series of sands,
the Sables du Maine, which enclose among other fossils Orbitolina
concava, Lam., T'rigonia crenulata, Lam., Tr. Dedalea, Park., Am-
monites [ Acanthoceras| rotomagensis (Defr.), A. Mantelli, Sow., and
Catopygus columbarius, Lam.

In the Perche district, the Sables du Perche, which contain Am-
monites [ Acanthoceras| navicularis (Sow.), Ostrea carinata, Lam.,
Exogyra columba, Lam., Rhynchonella compressa, Lam., and Trigonwa

Vol.53.] | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 593

crenulaia, Lam., belong to a higher zone than the beds previously
described, but are included in the Cenomanian series.

Guillier' has given a long list of the Cenomanian fossils in that
department, but unfortunately the poverty of the Irish fauna renders
comparison difficult. Nevertheless Orbitolina concava occurs at the
base of the French Cenomanian, increasing in abundance in the
upper strata, till near Le Mans a calcareous yellowish grit containing
abundant glauconitic grains and numerous quartz-fragments is met
with, yielding among other fossils Trigonia crenulata, and in lower
beds Ammonites [Schlenbachia] varians, A. [ Acanthoceras | Mantelli,
and small individuals of Ostrea columba.?

In the Sarthe Ewogyra columba gigas and Callianassa Archiacr
also occur in the Turonian.

In the Rhone Basin, as shown by M. Kilian, in the Montagne
de Lure,* calcareous grits with Exogyra columba, Ammonites [ Acan-
thoceras] rotomagensis, and Trigonia crenulata overlie a glauconitic
grit filled with Orbitolina concava.

Near Marseilles, at Escragnolles, grits with Exogyra columba
rest on grits and limestones containing a Rouen fauna, these again
overlying clays and limestones with Ammonites | Acanthoceras] Man-
telli and Orbitolina concava.

In the Gard also, glauconitic marls with Pecten asper, Trigonia
crenulata, and Orbitolina concava begin the Cenomanian Series,
being separated from a band with Exogyra columba by a fluvio-
marine formation. Orbitolina concava is also at the base of the
Cenomanian in Spain.

Finally, it may be mentioned that in the Orange district the
Maine beds reappear as a green sandstone or grit with Hwvogyra
columba ; but in this instance a bed with large Exogyra columba,
followed by a marly bluish limestone with Callianassa, actually
overlies a limestone containing Turonian ammonites.

With the above two exceptions, the whole weight of the evidence
is in favour of the view that the Chloritic Sandstones mainly repre-
sent the Cenomanian beds of Western England, at the same time
sharing the shore-line characters of the same strata in the West and
South of France. It is interesting to note that brown casts of
bivalves, probably Jnoceramus, occur in the sandstones at Colin
Glen, in this respect recalling the characteristic feature of the
Chloritic Marl at the base of the Cenomanian.

The lithological characters seem to point to depression and
subsequent elevation, the lowest or Pecten cequicostatus-beds being
sandstone, with very small glauconitic grains ; the Hxogyra columba-
layer above is green uncompacted sand with soft calcareous sand-
stone, the sandstone with but few glauconitic grains subsequently
reappearing in the Callianassa sub-zone, containing these crustacea
in abundance.

There is little doubt that Gault is right in noting a strong uncon-

1 «Géologie de la Sarthe,’ pp. 244-260, 2 Ibid. p. 226.
3 «Montagne de Lure,’ p. 293.

Q.J.G.8. No. 212. 2R

594 DR. W. FRASER HUME ON [ Dee. 1897,

formity at the summit of the Callianassa-bed, this being immediately
overlain by the conglomeratic mulatto-stone of the zone of Belem-
nitella [Actinocamax]| vera. The break is still more marked in
other portions of the Central Division, where the same zone overlies
the Yellow Sandstones with clear unconformable junction. The
Chloritic Sands of the Eastern Division mainly consist of arenaceous
glauconitic limestones (containing Jnoceramus-fragments and Spon-
dylus spinosus), which extend farther northward than the beds
previously described, thus presenting a distinct case of overlap.
Spondylus spinosus occurs in the Chloritic Sands as far south as
Cave Hill, and as far north as Glenarm. These beds are also present
in the Northern Division, as at Tircreven Burn.

Eastern Division. (Zone of Inoceramus Crispi 2)

While easily distinguishable from the greenish-yellow sand of
the Exogyra columba-zone, the Inoceramus-zone passes insensibly
above into that of Echinocorys gibbus.

Principal fossils :—Piscrs: Scapanorhynchus rhaphiodon, Ag.,
Ptychodus latissimus, Ag., Anomeodus sp.

GastERoPoDA : Pleurotomaria perspectiva, Mant.

Prtecypopa Monomyaria: Jnoceramus sp. (fragments abundant),
Ostrea semiplana, Sow., Pecten [Janira] quinquecostatus, Sow.,
Spondylus spinosus, Sow.

Bracurovopa : Lhynchonella plicatilis, Sow., Rh. limbata, Schloth.,

Rh. robusta, Tate.

VermeEs: Serpula filiformis, Sow.

Potyzoa: Spwropora sp.

Ecurnopermata: Micraster breviporus, Ag., Catopyqus colum-
barius, Lam. (both at the base). Cidaris clavigera, Konig, also
probably belongs here. Spines of Ozdaris sp. abundant.

At Woodburn, Larne, and Whitehead, we have in addition found
the following associated with, or below, the beds of Jnoceramus-
fragments :—Echinocorys vulgaris, Breyn., var. ovatus (Larne), and
E. gibbus, Lam. (Woodburn), Galerites albogalerus, var. angulosus,
Desor (Larne and Whitehead), Terebratula carnea, Sow. (flattened
type), ZT. semiglobosa, Sow., and Camerospongia fungiformis, Goldf.
(Larne). In general, however, these last-mentioned species are
restricted to the highest portion of the glauconitic sandy limestones,
beds which Tate would probably class with the Chloritic Chalk.

As already stated, the lowest 4 feet of glauconitic sand with
Vermicularie, Ostrea carinata, and Exogyra columba, must be

‘regarded as Upper Greensand or Cenomanian, the occurrence of.

Rhynchonella Schlenbacha in quantity at Whitehead also showing
the existence of the zone of Hwogyra columba in this division.
There is no apparent lithological break between these sands and
the overlying Shynchonella-band, but every evidence of the
existence of paleontological unconformity.

Having recently visited the Chalk Rock of Hertfordshire, etc.,

Vol. 53.] THE CRETACEOUS STRATA OF COUNTY ANTRIM. 595

I have been much struck with the resemblance which some of
the Irish fossils have to the English species from that horizon.
For example, the Irish specimens of Micraster breviporus agree
almost absolutely in size with those obtained from the base of the
Micraster cor-iestudinarium-zone in Surrey and at Eastbourne,
or from the Chalk Rock at Baldock, near Hitchin, while the
Rhynchonella plicatilis and Rh. limbata are very similar in both
cases. Also, as Barrois has urged, Spondylus spinosus, Ostrea
semiplana, and Inoceramus sp. are particularly abundant in the
upper part of the Turonian. The fauna, taken as a whole, may be
termed that of the reversing layer, or the point where the secondary
elevation leading to the formation of the Chalk Rock attained its
maximum ; and indeed, if anything, these sandy limestones have
been formed on the depression side of it.

Nor have I been able to confirm Barrois’s discovery of Galerites
subrotundus and Rhynchonella Cuviert. These must be uncommon,
and would consequently not affect the general Chalk Rock
character of the organisms present.

Looking at the question from a historical point of view, it would
appear that the Eastern Division of Ireland had now joined in the
great second movement of depression which appears to have begun
in England after the formation of the Chalk Rock, the shallower
waters of the Antrim Sea preserving the fauna of the transition-
period longer than was the case in England. If this view be
adopted, these beds will have to be considered as Lowest Senonian,
but still presenting a strong Turonian aspect.

Chloritic Chalk. (Zone of Echinocorys gibbus.)

The principal fossils are :—

Mottvsca : Spondylus spinosus, Sow.

Ecurnopermata: Echinocorys gibbus, Lam., Cidaris sceptrifera,
Mant. (probably).

Vermes: Serpula filiformis, Sow.

Crinompea: Bowrgueticrinus sp.

Bracuioropa: TLerebratula carnea, Sow.

Acttnozoa: Parasmilia centralis, Mant.

PoriFrERA: Camerospongia fungiformis, Goldf., Ventriculites sp.

This zone differs from the last, with which it is intimately con-
nected, only in the increase of the calcareous constituents and the
thoroughly deep-sea character of the fauna, the large mollusca
having almost entirely disappeared. It apparently represents, with
the sands previously described, the whole of the Lower Senonian,
minus the Belemnitella | Actinocamax| vera-zone. The main feature
is the abundance of Echinocorys scutatus, Terebratula carnea, and
Camerospongia fungiformis, all of which fossils connect it with
the zone above, but as B. [ Actinocamax] vera has not yet been
obtained in these beds, they must at present be excluded from that
zone.

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Vol. 53.] | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 597

«

Zone of Belemnitella [ Actinocamaz | vera and
B. [A.] quadrata.

It is very evident that it was during the period of these two
zones that the greater part of Antrim became submerged beneath
_ sea-level, with the production of mulatto-stone or conglomeratic
chalk in the Central Division, of Spongiarian beds in the Eastern
and part of the Central districts, and of beach-deposits in the
Peninsular area, while true White Chalk was already being
formed in the Northern Division. We have seen that Belemnitella
[ Actinocamax]| vera occurs in the conglomerate at Colin Glen,
in the Spongiarian zone of Islandmagee, and in the white lime-
stone of the Northern Division; B.[A.] quadrata (Blainv.) and
B. [A.] Alfridi, Janet, in the glauconitic rock of Forth River ;
B. [A.| quadrata and Micraster cor-anguinum in the nodular
glauconitic chalk of Squires Hill; and B. [A.] Alfridi together
with gasteropoda in the beach-deposits of the Peninsular area.
These zones have been at present classed together, because hitherto
the two zone-fossils have been seldom obtained in the same
locality; but when thus found, the rule usual elsewhere is followed,
B. (A.] vera being found in beds lower than those containing
B, [A.] quadrata.

The principal fossils are tabulated on p. 596. The fossils for the
Northern Division are enumerated on Barrois’s authority ; those
marked with a G have been recorded by Gault from the Central
Division.

Tate, in his table, places the Spongiarian zone and that of Anan-
chytes gibbus at the Belemnitella | Actinocamax] quadrata-level, but
the above fauna shows that these are, in part at least, of B. [A.]
vera-age. Barrois* also arrived at the conclusion that, whereas
the sponge-beds in Germany are mainly at the summit of the B.
[ A.] quadrata-zone (zone of Becksia Sekelandi, of Schliiter), those
in Ireland occur at the base of this zone, and the two are conse-
quently not comparable. Also, comparing the sponges obtained in
the Spongiarian zone with those from the well-known horizon at
Danes’ Dyke near Bridlington, there is no sponge common to the
two localities. Taking all the evidence together, there seems little
doubt that the pebble-beds, mulatto-stones, and Spongiarian beds
were formed mainly during the period of these two zones, the
latter being most certainly of B. [.A.] vera-age.

White Limestone. (Zone of Belemnitella mucronata.)

To this zone belongs the white hardened limestone overlying the
strata previously described, which forms so conspicuous a feature
in all the Antrim divisions. In the Southern, Central (Black
Mountain), and Peninsular areas, Belemnitella mucronata occurs in
a pebble-containing mulatto-stone.

Fossils.—General: Belemnitella mucronata, Schloth., Ammonites

1 «Recherches sur le Terrain Crétacé, etc.,’ p. 210

598° DR. W. FRASER HUME ON [ Dec. 1897,
gollevillensis, d’Orb., Turritella uncarinata, Tate, Trochus sp.,
Ostrea vesicularis, Lam., Terebratula carnea, Sow., Rhynchonella
plicatilis, var. octoplicata, Sow., Pecten cretosus, Defr., Magas
pumilus, Sow., Parasmilia centralis, Mant., Porosphera globularis
(v. Hag.).

Occurring mainly in the lower portions of the limestone :—Mosa-.
saurus gracilis, Owen, Terebratulina Defrancei, Brongn., T. abrupta,
Tate, Echinocorys scutatus, Leske, Megerlia [Kingena] lima, Detr.
(P), Callkostoma sp. (P), Catopygus columbarius, var., Lam. (P),
Galerites vulgaris, Breyn. ?, Holaster planus, Mant., Trochosmilian.
coral (P), Notidanus microdon, Ag., Pleurotomaria perspectwa,
Mant., Ammonites [Pachydiscus| Griffiths (Sharpe), and P. Old-
hami (Sharpe), P. peramplus, Mant., Nautilus Deslongchamp-
sianus, @Orb., NV. Largilliertianus, dOrb., NV. Atlas, Whiteaves,
Baculites, near anceps, Lam., Hamites sp., Anisoceras sp., Ventri-
culites sp., Caeloptychium sp., and the Kilcorig fauna (see p. 546).

Tate concludes that ‘the White Limestone certainly represents
the Upper Chalk of Norwich and the Craie de Meudon, and some
of its fossils point even to a higher parallel—that of the Maestricht
Chalk.’ Barrois also considers that these beds are on the level of
the Norwich Chalk, but sees no evidence of the existence of Danian
beds in this region.

It is clear that during this period the submergence of Antrim
must have been very complete, the whole of the divisions having the
White Chalk of this zone covering the older deposits, its preserva-
tion being due to the great overlying mass of basalt. The upper
part is very unfossiliferous, the varied fauna above described being
mainly developed at the base, though a small group of forms occurs
throughout the series. The basal zone is a glauconitic chalk in
most of the Southern and parts of the Central and Peninsular
districts; in the others it is a pure white chalk, the chemical results
showing it in some cases to be as pure as that of some of the
English Upper Chalk-zones.

The following are the main stratigraphical conclusions :—

1. The Glauconitic Sands, or zone of Haogyra conica, corre-.
spond in the main to the Devizes beds (zone of Ammonites inflatus).
and part of the Warminster Beds (zone of Pecten asper) in England.

2. The Yellow Sandstones, or zone of Ostrea carinata, are of
Warminster age, that is, the Pecten asper-zone of Barrois. ;

The above together correspond to the English Upper Greensand.

3. The Chloritic Sands and Sandstones (Central Division),
or zone of Exogyra columba, are true shore-representatives of the
Cenomanian (Lower Chalk) in Ireland.

4, The Chloritic Sands (Kastern Division) =zone of Inoceramus
Crispi? of Tate, are equivalent to the highest Turonian (Middle
Chalk) or lowest Senonian beds in England, being intimately asso-
ciated with the changes which resulted in the formation of the Chalk
Rock in England.

5. The Chloritic Chalk=zone of Echinocorys gibbus and

HyDROZOA AND

GASTEROPODA. EA.

[To face p. 598.

PORIFERA.

ee

Spicules abundant
in flints.

Ventriculites,

Coscinopora,

Celoptychium,
Hexactinellid band.

——

Glauconitic casts of

spicules abundant.

_——_—————— |

Glauconitic casts of

present.

ACTINOZOA.
Turbo, Trochus, Panes
= sphera,
Pe pda. Parasmilia
he base. centralis.
Turbo, Trochus,
Actazon, Emarginula.| |
Parasmilia
centralis.
Natica and oa
Aporrhais. i ane
Micrabacia
coronula.
; 2 c casts
LTittorina. oda. | oct

FoRAMINIFERA.

Abundant in flints,
silicified.
No Porcellanea.

Not examined.

External and internal

glauconitic casts
well-preserved.

Glauconitic casts

| Hexactinellid spicules | common, not specific-

ally recognized.

Glauconitic casts
common,
not specifically
recognized.

Rare.

Flabellina cordata.

Large glauconitic
casts abundant.

Quart. Journ. Geol. Soc. Vol. LIII.

LIV.—Tasre or GEneRAL Patrw#onronogicaL DistRIBUTION.

[Lo face p. 598.

Wonz. REPQILIA. PIsces. CEPHALOPODA. GaAsTEROPODA. ae eee ae HBUBUEEODS BRACHIOPODA. VERMES. Ecurnopermata, | Czrustacra. HT pROgOAEED PorrFERA. FoRAMINIFERA,
ps | coor bere one pe | Pee ama ee aa | > =A —<—— ——— ——___ —__
|
a Lamnide, Mylioba- | Pachydiscus, Nau- Turbo, Trochus, Ostreaoestoulanis Rhynchonella Borosphand Abundant in Sint
elemnitella Mosasaurus tide, Notidanide,| tidus, Baculites, Turrvitella. 2 i peters octoplicata a | Dehinocorys J eit Spicules abundant tant ints,
mucronata. Camperi. and Pyenodontide | Hamites, etc., at Pleurotomaria Pectew cretosus, Pholadomya, Terebratula eaieneay SMe scutatus. Ostracoda. Parasmilia in flints. silicified.
at the base. the base. at the base. Chie Magas. contralis. No Porcellanea,
Ventriculites
Belemnitella Bel. mucronata, Y é ?
s : e Tirbo, Trochus. a Micraster Coscinopora q
eee peeanca aeese ee Bali el ge ads Acteon, Emarginula| 99 Venus, vave. CRON ls |) ~ errs Galante Not examined.
q 5 : i Hexactinellid band.
if
— eee | —— ————— _—————— =
Belemnitella Belemnitella Marsupites, Cidaris, External and internal
[Actinocaman]/wenan|) 9 Gs ie saat [Excten occas ace) taier cs Nimmo ane || ee ay oir eats Poon |ihe Sos es erapsist WHOWEN, ff eee slauconitic casts
a3 well-preserved.
Glauconitic casts of
spicules abundant.
° 9 Terebratula carnea Serpula é E 5 Parasmilia
JOOS TOTO RD GARAGES ||) seccaseenetis = | oeendenacce) °C) sBaoteocea "ll. fesapuspeanoe Spondylus spinosus. abartdant filiformis-band. Hehinocorys gibbus. OEM SCHED,
Spondylus spinosus, Rhynchonella Galerites alboga- spe orc
i Foe Lamnide | Tnoceramus, and Rare plicatilis and | lerus, Cidaris, ean Scat ce Glaacenitio caate
TOE BT CATES 2 OTS Nacsa not verycommon. | 99" Ostrea semiplana ne. Rh. limbata abundant | Micraster breviporus| °° freee OR ACUTE Ae SP1CHeS | COM On UO ABeCl Gs
abundant. at the base. (base). present. ally recognized,
; — aS 5 Se —— se Ss —— —
| | | Terebratula Glauconitic casts
| 2 aad Pachydiscus lewesi- 9 Pectens (Janira) Sin ' hibernica above rete “5 Catopygus colum-
Exogyra columba. | | ely Melievinles cat ensis, according to | AE and GON @ eee a (one band). k ee: a barius, at the Calianassa-band.| ..-.ecceces | seen eneees common;
| Lamnide abundant. | ate, | Aor hans, Baxogyra common, | (7 0ttM"s ANGUNG Rhynchonalla epee: junction above. not specifically
Schlenbachi below. recognized,
|
omnee | Sel “|
0. 5 L | Ostrea carinata and | Avicula, Panopea, |Rhynchonella convera| Vermicularia | Discoidea subucula. Micrabacia Rare.
strea carinata. CHAINER =" | 2 2 © ooseetseces 00) | = Bare agaapte Lima sp. Pinna. fairly common. abundant. coromula. Flabellina cordata,
———— ee = ————— | ——_.- ————————— — ||
| Schlenbachia Pecten [Amussium] | Avi | Numerous small a .
| | ee wicula. (B.) | clinical Vermicularia at tye " S
Exogyra conica. | Plesiosaurus sp. ‘banina and Corax varias. CE) Tittorina. Pee fen [ Chlamys] Trigonie, Cucullea, Riga Be TE the top Glsucontt ees Bi eece the tore tll ere eee Large glauconitic
b ee eae (c,) slisaitann (02) Cyprina. | and Kingena. abundant, casts abundant,

Belemnites ultimus.

Baxogyra common.

[E.= Eastern Division.

C.=Central Division. ]

Vol. 53.| | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 599

Camerospongia fungiformis, represents the Micraster cor-anguinum
and part of the Marsupites or Belemnitella [| Actinocamax| vera-
zones.

6. The Spongiarian Bed must be classed with the zone of
Belemitella {| Actinocamax| vera. The mulatto-stones mainly belong
to the zone of B.[A.] quadrata, but also in part to the preceding
and succeeding zones.

7. The White Limestone is a member of the zone of
Belemnitella mucronata, there being little evidence in favour of the
existence of still higher strata.

The first four of the above divisions were classed by Tate as the
Hibernian Greensands, under the impression that all these beds
were Cenomanian. We have seen, however, as Barrois had already
pointed out, that the J/noceramus-zone cannot be thus regarded.
The first three might very conveniently be retained under the old
name; but if a short designation be needed for the Chloritic Sands
of the Eastern Division, the term ‘ Antrim Beds’ suggests itself to
me, which would include all the strata characterized by Spondylus
spinosus and Inoceramus-fragments, having the Spongiarian band
at the summit. The type-section for these beds is the quarry of
Barney’s Point, in Islandmagee.

LV. Generat ConsrpERATIONS.

Having dealt with the various lithological and zonal divisions in
detail, it will now be advisable to consider the general questions
which arise out of our previous study.

1. We have observed that there are certain organic remains in
the Glauconitic Sands and Yellow Sandstones of the Eastern
Division, which suggest higher zonal conditions than those indicated
by the species with which they are associated, and it is mainly
these which have guided Barrois in his classification of the lower
Irish beds. They play, it is true, a purely subordinate part in the
fauna, but their presence demands consideration, and various possi-
bilities may be suggested.

(a) The Eastern Division I regard as having been in deeper water
than the Central, firstly, because the detrital deposits are generally
thinner here than in the Central Division ; secondly, because
brachiopoda, corals, sea-urchins, and chlamyd bivalves are present
in its lower strata; thirdly, because large dimyarian bivalves, such
as the Trigonie, Arca, Thetis, etc., so abundant in the Central, are
very rare in the Hastern fauna. Again, there seems to be a growing
belief that the organic changes in the English Upper Greensand
are such as would result from gradual depression. It may be then
that this is a case where a deeper is co-existent with a shallower-
water fauna, and not successional, as in England.

(b) Another possible view is that an older fauna continued living
longer near the Irish shore than in England, where a deeper-water
one had already established itself, and had partly invaded the Irish
area. This seems to me less tenable than the first view, because all

600 DR, W. FRASER HUME ON [Dec. 1897,

the paleontological evidence points to the conclusion that during the
deposition of the Upper Greensand the English and Irish Cretaceous
seas formed part of the same geographical province.

2. A second difficulty arises in regard to the Chloritic Sands and
their divisions, the zones of Hxogyra columba and Inoceramus Crispi.
Why should the beds containing the former be developed on so ex-
tensive a scale south of Belfast, yet scarcely be known north of that
city ; and for what reason does the precise opposite hold good for the
strata containing Jnoceramus-fragments and Spondylus spinosus ?

The following suggestion appears to offer the best solution of the
enigma. The detrital deposits will be, speaking in general terms,
thicker nearer a continental shore-line than they would be farther
out at sea. Reasons have already been given for believing that the
Central Division was closer to land than the Eastern, and we have
seen that at Colin Glen the beds (largely composed of land-derived
materials) below the mulatto-stone are 60 feet thick. In the
Eastern area the corresponding beds do not, at their maximum,
exceed 30 feet. If elevation took place, the strata nearest the land
would first commence to be denuded, but, should the geocratic
tendency not be prolonged, being of considerable thickness, a portion
of the older beds would still remain unaffected by denudation. On
the other hand, the thinner strata formed in deeper water would be
less liable to denudation, and on depression recommencing, organic
calcareous deposits would commence to form earlier here than in the
littoral regions.

Our explanation, then, is this :—The strata of Upper Greensand,
Cenomanian, and Turonian age in Colin Glen, etc., were laid
down nearer shore, and were in consequence thicker than the
corresponding beds in the Eastern Division. When elevation
ensued, the Central Division was first affected by denudation,
and any Turonian or Upper Cenomanian strata that had been
formed were removed. On the other hand, in the Eastern Division,
the hydrocratic movements of the beginning of the Upper Chalk
period resulted in the formation of a series of strata of organic
origin, which are practically unrepresented farther south-west. As
a consequence, the unconformity in the Central Division is at the
summit, in the Eastern near the base, of the Chloritic Sands: the
ereensands included under this name being, in the two areas, of
different age, and, when carefully examined, of different characters.

3. In ‘The Genesis of the Chalk’’ the present writer has main-
tained that the zones of the English Chalk have been produced
during the course of three great phases of movement, the first of
submergence, lasting from the Upper Greensand to Terebratulina
gracilis-times (Middle Chalk); the second, of partial elevation, the
most visible result of which is the Chalk Rock; and thirdly, after
the formation of this prominent lithological feature, a further
period of submergence, far exceeding in magnitude the earlier

* Proc. Geol. Assoc. vol. xii. (1894) pp. 211-246.

Vol. 53.] THE CRETACEOUS STRATA OF COUNTY ANTRIM. 601

occurrence of the same nature. The three movements appear
to have left very marked effects in Ireland, these being inten-
sified owing to the immediate proximity of land. The changes
during Upper Greensand and Cenomanian times run parallel with
those taking place in Western England; but an elevation which, from
the Irish evidence, must have taken place later than the beginning
of the Cenomanian seems to have been the cause of the uncon-
formities which have been noted, especially in the Central Division.

The advance of the second submergence is marked by both overlap
and unconformity, the character of the incoming fauna being, as
already observed, of highest Turonian or lowest Senonian age, and
thus indicating that the oscillations were closely parallel, or con-
nected, with those occurring in the English areas. The first signs
of the new conditions are observed in the east of the Eastern
Division, where there is merely a slight trace of lithological uncon-
formity, but a considerable faunal break. The lower beds of the
Inoceramus-zone are limited to the centre of this division, but the
higher ones overlap the older strata both to the south and north,
invading the Central area on the one hand, and extending to Carn-
lough on the other. Approaching the Southern and Peninsular
regions, the unconformity occurs at the base of higher and higher
zones, until in isolated exposures in these districts the Belemnitella
mucronata-zone itself rests with an unconformable junction upon
strata of Triassic, Carboniferous, or even earlier age, so that at the
close of the Upper Chalk period every part of the Antrim area must
have been submerged.

4, One of the most interesting occurrences in this connexion is
the presence of definite beaches of Upper Chalk age, characterized
by the large size of the mica-schist and other fragments which
compose them, and at the same time containing a rich and dis-
tinctive fauna. These beaches, which have evidently been formed
during the period of maximum depression, are inhabited by two sets
of organisms, some, such as the gasteropoda and dimyarian bivalves,
being shallow-water inhabitants, others of deep-sea origin, but
stunted in growth because they lived under abnormal conditions of
depth, ete., the types being the small Galerites which are among the
commonest genera present. It is possible, indeed, to trace every
gradation from these undoubted beaches to the pebble-conglomeratic
limestones and mulatto-stones of the same period, these again passing,
by gradual diminution of the detrital constituents, into the glauconitic
and sponge-containing limestones of the deep-water divisions.

5. The geological evidence in favour of the existence of marine
currents must be, as a general rule, only indirect, but at times a
combination of circumstances unites to witness to their action.
For instance, in the Hwoegyra columba-zone especially, a number
of facts testify to the existence of a current of some magnitude;
thus, a new fauna, not previously represented in Ireland, replaces
the other species, individual forms by their abundance characterizing
bands of no great thickness and limited horizontal extension (as,

602 DR. W. FRASER HUME ON [ Dec. 1897,

for example, the Ewogyra columba-, Waldheimia hibernica-, and
Callianassa-bands), while a noticeable feature is the frequent
occurrence of the teeth of fishes (Lamnide and Myliobatide) in
the softer sands of the same zone.

I have already discussed the relation of a rich fish-fauna to
currents as follows:—‘The current will evidently carry along
with it large amounts of material derived from the littoral area, —
and far more suitable to a piscine palate than the usual minute
pelagic fauna of an oceanic region. The result would be that
comparatively shallow-water Teleostean fishes, such as Beryx,
would have their range greatly extended,.... whilst the rich
increase in food-material would tend to bring together large
numbers of predatory fishes, especially sharks, such as Lamna, ete.
In this way, perhaps, the discovery of such a rich fauna may be
explained.’* The same statements appear to apply to the case under
consideration, and in addition it should be noted that the associated
mollusca are distinctly littoral.

In the Inoceramus-zone the new fauna also appears in bands, but
here the incoming species have a deeper-water aspect, and the beds
containing them yield but few fish-remains.

Just as in the Central Division, it is below the unconformable
junction that current-action is most suggested, so also above it there
is strong evidence pointing in the same direction. Ground-currents
must have been especially active during the period of the Belemnitella
[ Actinocamaa] vera and B. [A.] quadrata-zones, judging from the
extraordinary admixture of the older and younger beds at their
junction, the nodular or conglomeratic character of the strata imme-
diately overlying the unconformity, and the large size of the detrital
materials.

The following appear to have been the principal currents :—
(1) One resulting from the changes which ushered in the Cenomanian
period, extending the range of a southern fauna northward, and
accompanied in its course by a number of predatory fishes. (2) One
commencing at the beginning of the Senonian, setting in from the
oceanic areas towards land, and introducing the deep-sea fauna,
unaccompanied by a prominent fish-fauna. (3) An indefinite current-
system, resulting from the submergence of the prominent land-
masses, and coincident in time with the Belemnitella [_Actenocamaz |
vera- or Marsupites-zone. This gives rise to marked lithological
disturbances and unconformities, and may have been synchronous —
with the deposition of the phosphatic chalks and nodular bands
common in many Cretaceous districts at this horizon.

6. Reference may now be made to the relation of spongiarian
bands to the subjacent and superjacent strata. It appears to me
that such bands in many cases immediately overlie or are directly
connected with beds displaying evidence of the commencement of
depression, or partial elevation of deep-water beds accompanied by
current-action. For example, outside Ireland, in the South-east of

1 «The Genesis of the Chalk,’ Proc. Geol. Assoc. vol. xiii. (1894) p. 233.

Vol. 53.] THE CRETACEOUS STRATA OF COUNTY ANTRIM. 603

England, mention may be made of the Plocoscyphia meandrina-
layer, lying immediately above the Chloritic Marl with its rolled
phosphatic nodules. With this exception, throughout tne whole of
the Cenomanian and Turonian periods, no such colonial assemblage
is again met with, until, at the very summit of the strata of the
latter age, the Chalk Rock displays evidence of partial elevation.
Analyses of the lower strata generally show no trace of glauconitic
casts of sponge-spicules, yet the Chalk Rock and Holaster planus-
beds of Devon, Eastbourne, and the Midlands, have without
exception yielded these as the most important members of the
residue. It is very interesting to find that precisely the same fact
holds good for the Jnoceramus-zone in Ireland, which I have regarded
as partly synchronous with the Chalk Rock of England. In Antrim
the abundance of these glauconitic casts of spicules is noticeable so
long as the limestones contain small fragments of quartz and other
detrital materials, but the sponges attain their maximum develop-
ment (forming definite bands) at the point where the detrital
minerals become rare, and pure white limestone is commencing to be
formed. In other words, the most favourable locality for the forma-
tion of a sponge-bed appears to be that one where currents are
carrying only the very finest particles in suspension, the sediment
forming on the ocean-floor being almost purely calcareous. But
although definitely recognizable sponge-beds cease at this level (the
base of the White Chalk), the continued presence of these organisms
in the chalk is evidenced by the abundance of flints.

If any one be yet inclined to dispute the connexion between flints
and sponges, I would call special attention to a memoir by Prof.
Sollas,, which had not come under my notice when discussing
these questions in previous papers. He remarks (op. cit. p. 488) :—
‘The Trimingham flints afford evidence straight to the point;
for not only are sponge-spicules intimately associated with them and
in great numbers, but these spicules afford us clear proof of the
previous existence of a great mass of other spicules of which they
are themselves but a miserable remnant.’ Considering the aggre-
gation of flints in layers, he concludes that drifting has not occurred
to any great extent, if present being only sufficient to help in
mixing the different sponge-spicules together (for, as Sollas, Hinde,
Wright, and others have shown, spicules of many genera have been
preserved intermingled in flints), but not to sort them out into any
distinct layer. His belief is, and personally I am inclined to adopt
the conclusion, that the area where the spicules are now found was
once a sponge-bed; with death and dissolution of the organisms the
spicules were set free from different adjacent sponges, and, falling
into the same deposit, naturally mixed together, movements of the
surrounding sea-water helping to render the mixture more complete.
Thus a chalky ooze would be produced, crammed with sponge-spicules
of all sorts and sizes. Such sponges as possessed skeletons compact
enough to maintain their general form after death would become
filled with this ooze, and, undergoing silicification, would furnish us

_ 7 Ann. & Mag. Nat. Hist. ser. 5, vol. vi. (1880) pp. 384-395, 437-461.

604 DR. W. FRASER HUME ON [ Dec. 1897,

with instances of fossil sponges presenting a well-preserved form
externally and a curious mixture of spicules within.

Considering the question of silicification as a whole, we are now
able to trace out some interesting facts with regard to the character
of the preservation of sponge-spicules and other organisms as
illustrated by the Irish strata :—

(a) In the Yellow Sandstones where detrital quartz is plentiful,
but fossils capable of silicification are not numerous, the sponge-
spicules which were present have been partly or completely dissolved,
giving rise to definite chert-beds or cherty nodules.

(6) In the Jnoceramus-zone and upward, the abundant glauconitic
casts of spicules prove the former presence of a sponge-fauna which
in other respects has left no trace of its former existence. The
silica, thus passed into solution, has been redeposited in the interior,
or as the replacement, of shells of Znoceramus and brachiopoda.

(c) Where large mineral fragments are no longer carried by the
currents, solution appears to have been at its minimum and glauco-
nitic replacement absent, the result being the preservation of the
sponges and the formation of a definite sponge-bed.

(d) In the pure limestones the solution of the spicules is again
considerable or complete, and organisms capable of silicification are
either small or rare, so that a great excess of colloid silica is formed,
which is subsequently redeposited as flint.

In addition to the formation of flint, silicification has proceeded to
an extraordinary extent in the chalk, as is seen from the statement
of Mr. J. Wright,’ after examining the powder in the interior of a
number of flints:—‘ Among the many specimens collected from these
various places, I have recognized, besides corals and polyzoa, 17
species of ostracoda, 106 species and well-marked varieties of
foraminifera, and 27 forms of sponge-spicule; many of these
attain fine proportions, being much larger than those usually obtained
from the washings of English Chalk. The microzoa, on being placed
in hydrochloric acid, were found to be either not at all or but slightly
affected by it, showing that their original composition _ to a
great extent, been replaced by silica.’

The same statement holds good for the spicules described by Dr.
G. J. Hinde from the Upper Chalk of Horstead, and Prof. Sollas has
also discussed and emphasized the same point in the paper mentioned
above, laying stress on the fact that when siliceous solutions are
present they replace the molecule of carbonate of lime as a whole.
In consequence of this latter property, not only internal casts, but
absolute replacements of the original tests are met with.

Glauconite appears to behave in a precisely similar manner, the
internal casts being frequently of a very perfect character. Prof.
Sollas has suggested that these may be the result of the combination
of silica, set free from decaying sponges, with alumina, iron, and
alkalies, to the entire exclusion of lime. At present I am unable to
obtain any evidence of the existence of sponges during the formation
of an extremely rich deposit of glauconitic grains, as, for example,

1 «Trish Cret. Microzoa,’ Proc. Belfast Nat. Field Club, ser. 2, vol. i. p. 74.

Wol.63. | THE CRETACEOUS STRATA OF COUNTY ANTRIM. 605

the Glauconitic Sands. It might be argued that this is due to the
fact that the sponges yielding the necessary silica had entirely dis-
appeared, but this reply is unsatisfactory, in that it is based entirely on
negative evidence. The points on which I would lay stress are.:—
(a) That glauconite is an extremely variable mineral, casts of light
yellow to dark green colour being indiscriminately ranged under this
name. ((3) There does appear to be a definite relation between glauco-
nitic formation and depression, the glauconitic grains diminishing in
size and quantity as the calcareous element increases ; but we are still
very much in the dark as to the precise relation of glauconite to the
detrital materials on the one hand, and the organic tests enclosing
or replaced by it on the other.

7. The reappearance of species in higher zones after having
seemingly disappeared has been frequently noted by students of
Cretaceous geology. Thus Mr. Jukes-Browne, speaking of the
Chalk Rock of England, remarks that some of the species in it are
indistinguishable from those of the Chalk Marl nearly 400 feet
' below,! and Mr. H. Woods, dealing with the mollusca of the Chalk
Rock, says:—‘ As a whole, the fauna presents a much greater
resemblance to that of the Lower 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.’” In Ireland the fauna, which has thus been repeated at
these widely differing horizons, is carried a stage higher, Ammo-
nites (Pachydiscus, including P. peramplus, a common Middle Chalk
species), Hamites, Anisoceras, Baculites, Nautilus, and examples of
Holaster planus, together with forms of Turbo, Trochus, Emarginu-
lina, etc., having been found in some abundance at the base of the
Belemnitella mucronata-zone. The general aspect is undoubtedly .
similar in many respects to that of the Chalk Rock, and this fauna
must have continued to exist throughout the Upper Cretaceous age in
portions of the Chalk sea, being enabled from time to time to extend
its range as the result of movements of elevation or depression and
current-action.

8. The general distribution of the Rhynchonelle and Terebratule
is also not uninteresting, as the former seem, in the Irish strata at
any rate, to have been capable of existing under conditions and
circumstances which are not so favourable to the growth and
development of the latter. Thus, while in the Glauconitic Sands
both families are found together, in the beds formed largely of detrital
materials, such as the Yellow Sandstones and lower beds of the
Chloritic Sands, species of Rhynchonelle are alone met with, the
_ Terebratule being rare or absent, and only as depression advances

becoming predominant. The Rhynchonelle appear also to have
been capable of existing in the conglomeratic beds of the Peninsular
Division, where, so far as I am aware, Terebratule have never yet

1 ¢ Building of the British Isles,’ 1888, p. 177.
? Quart. Journ. Geol. Soc. vol. lii. (1896) p. 69.

606 THE CRETACEOUS STRATA OF COUNTY ANTRIM. [ Dec. 1897,

been met with ; it is only in the quietly-deposited White Chalk that
the two families are again found to co-exist.

This also appears to hold good to some extent for the English Chalk,
the Rhynchonelle being most marked in the marly or nodular strata
(2th. Martini in the Chalk Marl, and Rh. Cuvieri in the Inoceramus
labiatus-beds), while Yerebratule are more conspicuous in the
calcareous deposits (7. semiglobosa in.the Grey Chalk, and T. carnea
in the White Chalk of the Sencnian and Turonian), The uppermost
beds of the Upper Chalk agree with the corresponding Irish
Cretaceous strata in having the two occurring together.

Discussion.

Prof. Jupp congratulated the Author on having been able, while
dealing with a multiplicity of details, to bring out clearly their
bearing on some very important generalizations. He thought that
when the Author’s valuable studies concerning the insoluble residues —
of the Cretaceous rocks were completed, geologists would have in -
their possession a body of facts of great interest and suggestiveness.

Prof. G. A. J. Cote remarked that the custom among Irish
geologists has been to speak of the glauconitic and conglomeratic
beds of the Cretaceous as the ‘Hibernian Greensand,’ without
necessarily correlating these beds with the Upper Greensand of
England; and probably even the term ‘ Upper Greensand’ on the
Geological Survey maps may be regarded as mainly a lithological |
convenience. Irish workers would heartily welcome the correlation
of the zones now put before them ; and the speaker was glad to see
that no great break was insisted on in the Turonian Series. Geo-
graphical considerations as to the shore-line of the Cretaceous
sea are complicated by the very considerable earth-movements that
both accompanied and followed Kocene times. The base of the
Templepatrick section would be of interest for comparison with the
evidence given by the coast north-east and south-east of it, as bearing
on any possible division between a northern and a southern area.

Mr. W. Wurraker and Prof. H. G. Szetzy also spoke.

The AvrHor, in answer to Prof. Cole, said that he had not
examined the large quarry at Templepatrick, but its position suggests
an intermediate character in its relations, as it is situated between
the typical Eastern and Peninsular districts. In answer to
Mr. Whitaker, he observed that the average thickness of the Chalk
is about 50 feet south of Belfast, up to 80 feet north of Glenarm,
and 100 to 200 feet near Portrush and Rathlin Island. In answer to
Prof. Seeley, he pointed out that the Gault and Upper Greensand
have not been absolutely separated in the paper, while the nodular
beds resembling those of the Jnoceramus-labiatus zone are found
immediately above the unconformities, and belong to the three
Belemnitella-zones (B. vera, B. quadrata, and B. mucronata),
according to their position.

Quart. Journ. Geol. Soc. Vol. LITT. Pl, XLIV.

Uprpr Cretacrous Pespsire-ConaGboMERATE AT THE BASE OF THE CHALK, OVERLYING MARLS AND SANDSTONES
oF Trrasstc ach, MurtovueH Bay, near BattycastLE, Co. ANTRIM.

[Copyright kindly lent by Mr, J. R. Welch, of Belfast. ]

Belemnitella

7 mucronata-
| 20! zone
| ‘or White
mestone with
a Limestone,
tic sandstone with regular
a a see aR Se eee eee eee eee eee el
bands of
4'
; flints,
}
| over 100 feet
levigata. :
thick.
20'
4!
+

Belennitella quadrata at base.

White Limestone with three
bands of flint.

Inoceramus-fragments.

Flintless Chalk.

Belemnitella vera- and
Marsupites-zone.

Nodular band.

Limestone with little glauconite.

Glauconitic Chalk with phos-
phatic nodules. Echinocorys
gibbus at base and spenges.

at thickness of the detrital beds in the|the unconformity represented by the broken line.

Oouis Gunn :
(Cunrran Division), 9

White Limestone
with regular
layers of flint.
=Zone of
Belemnitella
mucronata,

20!

Belemnitella
vera-zone,
Nodular Layer.

Callianassa-
beds,

15!

Tei
co/umba-beds.

with
bands of chert:
=Zone of
Ostrea
carinata,

will

/Glauconitic Marla with
Cd Vermicularia,

Glauconitic Sands

Exogyra levigata,

ici

ComPARATIVE SERIES OF DIvISIONAL SECTIONS IN THE CRETACEOUS SrraTA or County ANTRIM.

Quart. Journ. Geol. Soc. Vol. LITT. Pl. XLV.

SouTHERN AND
Pentnsunar Divisions. _-

Woopsvrn Gen
(astern Dryiston).
South.

White
Limestone
with
regular bands
of flints.

White Limestone
with regular

bands of flint. White Limestone

=Belemnitella with regular
ronata- fi
mule) 'a-Z0Ne. flint-
2-4! ~
Spongiarian layer. layers.
‘ ESS =Belemnitella
Eehi eorye gibbus-band. mucronata-
Pink Limestone. a a 2
ill cap-anl ee er fy] Serpula filiformis-band. ~~ Zones
Sponge-nodules 20/ : a

1st Inoceramius or Ostrea
semiplana-band.

g F
Sasa

Sandy glauconitic limestone with
Spondylus spinosus.

sor 2nd Inoceramus-band:
Inoceramus-band,
iti Rhynchonella-band.

Yellow-green Sands

1s with
aon 4! with Bzogyra columba,
Vermicularia, etc.
“— Glauconitic

‘\ Sands with
Exogyra conica, var. levigata.

Yellow
Sandstone

20'

4 Glauconitic
Sands with

Pectens.

Barney's Point
(Eastern Dryiston).
Hast,

Norruern Division.

Belemnitella
mucronata-
zone

‘or White
Limestone,

with regular

bands of
flints,
oyer 100 feet

thick.

Belemnitella quadrata at base.

White Limestone with three
bands of flint.

Tnoceramus-fragments,

Flintless Chalk.

Belemnitella vera- and
Marsupites-zone.

Nodular band.

Limestone with little glauconite.

Glauconitic Chalk with phos-
phatic nodules. Hehimocorys
gibbus at base and sponges,

Notz.—This table shows the thickening of tho limestones northward, the great thickness of the detrital beds in the Central, and of the calcareous beds in the Eastern Division, respectively below and above the sifega foenity represented by the broken line.

Vol. 53.] THE BAJOCIAN OF THE CLEEVE HILL PLATEAU. 607

37. Dzposrts of the Basoctan AcE in the NortHERN CorrEswoLps :
The Cuzrve Hitt Prarzav. By 8.8. Bucxmay, Esq., F.G.S.
(Read June 28rd, 1897.)

[Prarz XLVI—Map.]

ConTENTS.
Page
MBS npromirc One aeccunaspuconn sade toamentec san eunti<teotmeesoaswisuceceyennas 607
mC Sections Gf the: Deposits’ ’*. .kss. severe sues eesscitnaeseseaatscreeaien 608
1. Whittington.
2. Cleeve Hill (generalized).
ITI. Notes concerning the various Deposits ............cccsceeeeneeees 610
IV. The Sequence of Cotteswold ‘ Inferior Oolite’ Rocks ......... 615
V. Correlation of the Cleeve Hill Deposits with those of other
ORIEN Sastsestnk etk.c a. «<ctacds Sad doe econ scaev cena wideaonss 617
WAS The Structure of Part of Cleeve aU ee iak, ....c.ceoceecasr vases 617
Vie The Bajocian Denudation,. oi: i... .cceeee cess ca ceoneetentar<seecacse 620
Woe Denudation and Overlap ..2:.02t. coseseedteaccssacoseesesesdoecssaes 623
BOX) (As Waber-retaiming eG. 1... ic csc detidaccetceeeen dein vaste bvidn bees 624
X. Ancient Geography of the Cleeve Hill Plateau...............++ 625
pal, Map of the Cleevedlill Plateau ..5.aieskeesscnaasewaseseseiiecee0s 0c 627
Peri Conglusion and Sumimary,...1.2 i. <.cdceweeestncsev-conseoss=tnoursn ee 627

I. Inrropuction.

Tue present essay is in continuation of a former paper which
described deposits of similar date in the Mid-Cotteswolds.' The
district now under discussion consists of an outlying isolated
plateau, cut off from the main mass of the Cotteswolds on the east
by the deep valley at Sevenhampton, and separated from the
Mid-Cotteswolds by the Vale of Whittington.? The best-known
portion of this plateau is called Cleeve Cloud or Cleeve Hill;
other portions include the hills above Whittington and Hewlett’s
Hill. For the purpose of the present paper the whole will be
named the Cleeve Hill plateau.

The literature relating to the district is not extensive. The
latest detailed section is that of Cleeve Hill given by Wright.’ As,
however, the sequence of the strata set forth by that author differs
so considerably from that which will be described in the present
communication, it is not thought desirable to discuss his section in
detail, or to combat his views. An almost entirely new reading
will be presented now.

One more point may be referred to. A postscript to my
communication on the *‘ Mid-Cotteswolds ’ (p. 461) first gave a short
summary of the sequence found at Cleeve Hill. Further researches
fully tended to bear out this sequence; and then, within the last

* <The Bajocian of the Mid-Cotteswolds,’ Quart. Journ. Geol. Soc. vol. li.
(1895) p. 388. Further references will be given simply as ‘ Mid-Cotteswolds.’

* This is a lateral valley of the Coln, made by a former tributary of that
river. Its western end is now deepened to form the valley of the Chelt.

° *Monograph of the Lias Ammonites,’ p. 155 (Paleont. Soc. 1879).

608 MR. S. 8. BUCKMAN ON THE BAJOCIAN [ Dec. x8o77

few months, an important portion of the Rolling Bank quarry has
been opened up, showing, in one exposure, confirmation of what
was before an inductive surmise from the piecing together of
several.

Il. Tue Sections oF tHE Dzpostts.

It is desirable to commence with the southern portion of the
Cleeve Hill plateau, at the hills above Whittington village, where
the following sequence of deposits may be found :—

1. Whittington: Ragstone Quarry and Fields ; about 600 yards
nearly north of the Church.

Ft. ins.
Urrer Triconta- 1. Shelly ragstone.
GRIT.
T. Puinurestana- 2. Greyish and yellowish-green sandstone,
AND BourGuETIA- with Terebratula Buckmaniana.: Several
BEDS. pieces of this matrix are much bored by
annelids. Also stones of a more or less
IPOUSHOL MAWINGsness boeken about 23 0
WircHe.uis-BEps. 3. Shelly ironshot with Acanthothyris... about 3 O
Noterove Free- 4. A whitish oolitic stone. A Sonninia of the
STONE. jisstlobata-ovalis type was found at the
bottom. This deposit is fully exposed in
He quanry , ~.. cmaduscoe os -osisescncenteneeeenee 18 0
GRYPHITE-GRIT. 5. A shelly ragstone with Gryphee and small,
smooth pectens, exposed for about ...... 3 0

(The quarry has been worked about 6 feet
deeper, and the spoil-heaps show a sand-
stone with Terebratula Uptoni. The
horizon of this fossil at Charlton Common
is 7 feet below the top of the Gryphite-
grit.)
Note.—The details of Beds 1-3 were obtained by breaking the stones in the
soil of the field to the northward, measuring the rise of the ground, and
allowing for the dip.

In the Cold Comfort district, which lies about 2 miles to the
south-east, the Upper Trigonia-grit rests on the Witchellia-beds.”
Here is found an additional amount of about 20 feet of deposit
separating these two beds.

About 6 furlongs to the north-east, where the ‘ White Way’
runs through Puckham Wood-—close to the fault which has let in
the so-called Stonesfield Slate beds of Bathonian age,—the Not-
grove Freestone may be seen at the south side of the road near
the top of the hill. Higher up the hill, in a field behind, the
Phillipsiana-beds may be recognized, not only by the distinctive
matrix, but by Terebratula Buckmaniana and other fossils. The
same beds may be discovered in the stones of the field just above
Wontley * Farm, about 1 mile 5 furlongs farther north; they are

1 Concerning this species, see ‘ Mid-Cotteswolds,’ p. 454.

2 “«Mid-Cotteswolds,’ pp. 416, 417.

3 The l-inch Survey Map has Huntley; the 6-inch, Wontley. The latter
is correct. It is the dialect wont or woont,a mole, from the Anglo-Saxon wand.

Vol. 53.] DEPOSITS OF THE CLEEVE HILL PLATEAU. 609

close to the 1000-foot contour-line. The other beds between these
and the Harford Sands inclusive (see p. 615) may also be found
there.

It is now advisable to go to Cleeve Hill itself, and of the
numerous exposures to be seen on the Common to give the fol-
lowing generalized section of results. Afterwards it will be stated
where the different beds may be examined to the best advantage.

2. Cleeve Hill ; a generalized section.

Ft. ins. Ft. ins.
Ouypeus- and’ I. 1. Yellow ragstones with Terebratula ;

UprErR globata. In the lower part are
TRIGONIA-GRITS. numerous T7rigonie and Rhyncho-
nella angulata .........corsee AOU: nvegavrs 15 0
TrreBratuLaA II. 1. Bluish-grey, sandy stone, sharp
PHILLIPSIANA- fracture. Bored by annelids and
BEDS. THORON cca ee 0 4

2. Similar stone, not bored, but some-

what rounded in places, and with

SAM G-POCHEES \...52--.cnancdeenmen besa 0-6
3. Similar deposit ; 3 beds with sandy

partings. Terebratula Phillipsi-

ana, var., sparingly [Upton]...... 5 0
4, Similar splintery grey limestone

with Terebratula Phillipsiana

and 7. Buckmaniana abundant.

‘ Rhynchonella quadriplicata.’

Acanthothyris. Two beds with

sandy partings, and a sandy base

Wath Ovabens, - Sate eee ee or 2 3
5. Similar massive stone. Terebratula

Phillipsiana, ‘ Rhynchonella qua-

driplicata’ {Upton}. Large

§ Bourguetia striata’ ....c.ccceceee x 0
—. 1G: 3
Bovrevetia- III. 1. Greyish shelly stone with brownish
BEDS. patches and infillings. Ctenos-
treon pectiniforme or proboscideum,
ORM 5 cercasaasde eds sadaceads 2 3

2. Grey stone in several beds. La-
mellibranchiata are numerous and
particularly noticeable for their
unusually large size. Large,much-
plicate Ostrea, Myoconcha, ete.

Large Nautilus.........csssssecss-oee RAL
3. Grey shelly limestone, somewhat
ONE oi sas ascetic ageaavan saeeeeee ae 1 6
&- NUGORDONG "so: caenteeesen sane 0 9
5. And there is presumably of this
deposit about another............... 2 0
15 G

1 A large, umbilicate, much-compressed, crassicostate Stephanoceras was
found by Mr. C. Upton 2 feet 9 inches below the Terebratula Buckmaniana-
bed. Its matrix and position indicate this bed No. 1,

Q.J.G.8. No. 212. 28

610 MR. S. 8. BUCKMAN ON THE BAJOCIAN [Dec. 1897,

Ft. ins. Ft. ins.

Wircnetia- IY. 1. A considerably ironshot stone. In
BED. the upper and much-ironshot part
are found specimens of a small

Acanthothyris rather frequently.

About the middle Witchellia sp.,

and also Terebratula Wrighti

about 13 feet above the Notgrove

Freestone, some specimens also

occurring in a bed of marl. Thick-

ness of this deposit about ......... ...s..: 4 0
NotTGROvVE V. 1. White oolite. The average result
FREESTONE,. of various measurements gives the
; thickness stated ; there is no com-
PICLE EXPOSULE: «2s2..eencceeccenaces ees eee “> 20250
GRYPHITE- VI. 1. Ragstone with numerous Gryphee.
GRIT. There is no complete See
oe: The thickness may be estimated... ......... 5 0
TrrREBRATULA VII. 1. Grey shelly limestone about......... 12)
BuckManI- 2. Grey clay-bandwithsmallGryphee. 1 0
GRIT. 3. Grey limestone about ............... 4. OO
17~ 0
Lower Tri- VIII. 1. Ironshot oolite, numerous lamelli-

GONIA-GRIT. - pranchiata, Aulacothyris Meriant,
about 2 feet 6 inches from the
base. No complete exposure.

Mhickness Perhaps .6..../-00s-.case) Soeeeeeee 7 0
SNowsuILL IX. Wo "Greyish jourplo marl... ..cccesscse 0 3
Cuay. 2. Very stiff, soapy blue clay............ 0 6

3. Sticky brown clay enclosing grey
stone-band, 2 inches thick, shelly,

with black streaks ......s..essss00- OOF
_— 1 4
HARFORD X. 1. Greyish-yellow, sandy, somewhat
SANDs. calcareous stone, Terebratula cf.
SHOMIGDULOUE..cuncetpwescthccensceeeore 2 0
2. Whitish and greyish-yellow, fine,
RINCEONS SANG Coete act mnaseem eet 3 0
5 0

Uprrr Frez- XI. Pinkish limestone at the top.
STONE.

Such is the sequence at Cleeve Hill of the ‘intervening beds “—
the deposits which part the Upper Trigonia-grit from the Upper
Freestone. Upon them remarks may now be made, and the places
where they can be seen to advantage may be noted.

III. Nores concerniné THE VARIOUS Dzpostts (the ‘ intervening
beds’ between Upper Freestone and Upper Trigonza-grit).

(a) The Harford Sands.

The sequence connecting these sands with the Lower Trigonta-grit
may be seen on the western side of the hill, just below the Rolling
Bank. About 14 foot of white and yellow sand is exposed; then

1 This estimate is uncertain.

ee

vol. 53. | DEPOSITS OF THE CLEEVE HILL PLATEAU. 611

there is a break, and a little lower down the bed described as
Upper Freestone is seen. The relation of the sands and Lower
Trigona-grit may also be seen on the eastern side of the hill above
<The Ring,’ near the 1000-foot contour-line. Relative position,
but not actual sequence, may be observed at ‘ Roadstone Hole.’

The sands cover a considerable part of the hill, and have been
extensively worked. It is reported that they were dug for use in
the Staffordshire potteries, and that they were conveyed thither
upon the backs of donkeys. ‘The presence of the sand is often indi-
cated by the gorse-bushes. The stone-bed (No. X, 1) is sometimes
partially disintegrated into nodule-shaped masses,’ which then
have the appearance of boulders, and have been the cause of some
confusion in the matter of Northern Drift. There is a specimen in
the Gloucester Museum which was obtained from ‘Roadstone Hole,’
and preserved as an example of that drift!

(8) The Snowshill Clay.’

This clay may be seen at the western side of the hill, lying over
the Harford Sands, as noted above; the measurements given were
taken therefrom. It may also be seen at ‘ Roadstone Hole’ capping ~
the sands just under the turf, and it seems to attain a thickness of
2 feet. At Leckhampton Hill is the first south-westerly exposure,
a bed 2 inches in thickness, marked as ‘ Harford Sands equivalent.’
Northward it would seem that the deposit attains considerable
proportions, for. between Snowshill and Broadway is a stratum
of this clay, whereon grow oak-trees and thorn-bushes—signs of
an argillaceous bed; and it must be several feet in thickness, for
there was a pit about 4 feet deep, while beyond that the ground rose
considerably. Therefore, for distinction, the name ‘ Snowshill’ has
been used, because this is a bed of considerable economic importance
(see p. 624). It may be remarked that the clay occurs above sand,
so that the order is

Limestone (Lower Zrigonia-grit),
Clay (Snowshill Clay),

Sand (Harford Sands),
Limestone (Upper Freestone),

which is somewhat unusual.

The chief interest of the further exploration of the Northern
Cotteswolds will be the development of the Harford Sands and
Snowshill Clay, or beds nearly contemporaneous therewith.

1 The bed consists of very fine quartz-grains and calcareous cement. The
rain gradually dissolves the cement, and leaves the grains incoherent as sand.

2 For notices of the clay-bed, see H. B. Woodward, ‘ Lower Oolitic Rocks
of England, Mem. Geol. Surv. : J urassic Rocks, vol. iv. (1894) pp. 126, 127,
137-143. The section on p. 143 may particularly be compared with details
given in this paper. The clay is classed with the Harford Sands.

3 « Mid-Cotteswolds,’ p. 410. At Chedworth Wood there is 6 inches, <bid.

. 425.
2582

612 MR. 8, 8. BUCKMAN ON THE BAJOCIAN [Dec. 1897;

(y) The Lower Trigonia-grit.

This deposit may be seen overlying the beds below it in sequence
at the places already noted. Its connexion with the 7. Buckmani-
grit may be seen at ‘ Roadstone Hole,’ especially at the eastern end.
There is, however, no complete section to show the exact thickness
of the whole bed. The deposit has just the lithic* character of the
same bed in the Mid-Cotteswolds, and the distinctive fossil Aulaco-
thyris Meriani has been found.’

(6) The 7. Buckmani-grit.

This bed is worked for roadstone. Hence the name ‘ Roadstone
Hole,’ applied by the workmen to the quarry, where its relation to
the Lower Trigonia-grit may be observed. There is shown, about
4 feet above that bed, a seam of marly clay similar to the deposit
in which Terebratula Buckmani is found in the Mid-Cotteswolds ;
but that fossil I have not found in it here. However, it occurs on
the spoil-heap of the ‘ Roadstone,’ where Terebratula Uptoni and
an Acanthothyris have also been found.

The beds of roadstone at ‘ Roadstone Hole’ are inclined at a
steep angle of about 55°, dipping to the north, and on account
of their disturbed and tumbled condition it is difficult to say what
their exact thickness may be. No section shows their relation to
the Gryphite-grit.

(c) The Gryphite-grit.

The greater part of this grit,? and its connexion with the Not-
grove Freestone, may be clearly seen in the quarry above, and to the
east of, the Rolling Bank, near the Ordnance-datum 972 on the
6-inch map. Similar observations may be made at the Whittington
quarry. Just south of the Rolling Bank the Gryphite-grit, with
Notgrove Freestone above it, is obscurely shown.

(¢) The Notgrove Freestone.

The connexion of this bed with the overlying Wétchellia-grit
may be seen in the Rolling Bank Quarry, as well as in the quarry
to the east thereof. No section allows of its full thickness being
accurately measured. The nearest approximation is obtained at
the Whittington quarry ; and estimates show that it may be some-
what thicker near the Rolling Bank. The section (Diagr. I, p. 614)
showing the quarries east of the Rolling Bank, and the relation of
this to overlying beds, also indicates how the thickness may be
measured approximately.

1 «Zithiec, pertaining to stone; ‘lithological’ signifies pertaining to the
science of stone, which is not the required meaning.

2 ‘Mid-Cotteswolds,’ p. 413.

8 There is 5 feet of Gryphite-grit ; and that is the whole thickness of the bed
at Leckhampton Hill (‘ Mid-Cotteswolds,’ p. 410). About 4 feet of Notgrove
Freestone is exposed above that east of the Rolling Bank.

Woll 5,3. | DEPOSITS OF THE CLEEVE HILL PLATEAU. 613

(n) The Witchellia-grit.

This bed may be seen in connexion with overlying beds at the
southern end of the Rolling Bank quarry, but the tumbled and much-
inclined condition of the strata makes exact measurement difficult.
Its general relation to the overlying strata may also be seen in the
quarries east of the Rolling Bank on the same line of fault.

The bed is similar to the deposit described at Cold Comfort,*
perhaps rather more ironshot. It has yielded characteristic fossils,
namely: Terebratula Wrighti, an Acanthothyris, and species of
Witchellia, all of which identify it with the Cold Comfort deposit.
The exact thickness of this grit is not yet ascertainable.

(0) The Bourguetia- and Terebratula Phillipsiana-beds.

These beds form the particularly interesting feature of the Cleeve
Hill plateau, and the recognition of their true position is the most
important point in the geology of the district (see Diagr. I, p. 614).
These deposits are not found on the southern side of the Chelt Valley,
for instance at Cold Comfort, and there is considerable justification
for the statement that they are not to be found anywhere else
in the Cotteswolds, except upon the Cleeve Hill plateau. Therefore,
as the Cotteswold rocks have particular characters of their own,
and a somewhat special fauna, because they were deposited in
an area which had somewhat imperfect connexion with other areas
of the same date, it may be said that many of the fossils which the
Bourguetia- and Phillipsiana-beds yield are not to be found any-
where else except upon the Cleeve Hill plateau. The Bourguetia-
beds are to be distinguished from the Phillipscana-beds by a
difference of matrix. They yield numerous species of unusually large
lamellibranchiata, and broken specimens of a large Bourguetia are not
uncommon. One Stephanoceras has been obtained (p. 609, footnote).

The Phillipsiana-beds are easily recognized by their bluish sandy
matrix. They yield chiefly species of brachiopoda, namely: Tere-
bratula Phillipsiana, T. Buckmaniana, a Zealleria cf. Leckenbyi, and
an <Acanthothyris. The Upper Trigonia-grit lies non-sequentially
upon the Phillipsiana-beds, because their top is considerably bored ;
moreover, the boring must have taken place after the beds had
consolidated to become as hard as their contained shells, because
the bore-tubes pass through stone or shell with equal indifference.

The date of the Phillipsiana- and Bourguetia-beds is probably the
Savzei hemera. The Stephanoceras obtained agrees closely with
species of this date from Dundry and Dorset. It is presumable
that the Phillipsiana-beds do not represent any part of the Hum-
phriesianum-zone, and that therefore the non-sequence between
these beds and the Upper Trigonia-grit was occasioned by denuda-
tion during the hemerz of Humphriesianus and niortensis—that at
any rate there are, at Cleeve Hill, no remains of any deposits
laid down during one or both hemere.

1 *Mid-Cotteswolds,’ p. 417.

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OT} JO SSOUWOIT, PUB VOIsse0ons oT} YOIYM Wory ‘Sortzenb oy} Ur eyqista ATLeENJow SVM FVI[Ar OLS suOl}10d pepegs ely,

[yoy G = "GUE [ : [eJUOZAOY pue [BoTzt0A ‘apeog |

OUIT asDg a7) Pay
Seay A 45
flog'fo doy ~ hasnnd’
wil OURO ya1m euop ganna sate
Ss Ewe esesee=

syung buajoay ay2 f0 sna sartunn’)—T WeIsBi(y

Vol. 53.| THE BAJOCIAN OF THE CLEEVE HILL PLATEAU. 615

Therefore the sequence of Bajocian deposits is still incomplete in
the Cotteswolds.

To show how partial is the preservation of the Bourguetia- and
Phillipsiana-beds it may be noticed that at Farmcott Wood, on the
top of Sudeley Hill, 4 miles east of the Rolling Bank, these beds
and the Wetchellia-grit have disappeared, and the Upper Trigonza-
grit rests directly upon Notgrove Freestone, whereof 15 feet is
shown. In a southward direction the same superposition is found
in 53 miles—at Leckhampton* and at Rough Hill Bank.? What
was effected by Bajocian denudation to the north will never be
known, because all the strata have been removed in the excavation
of the Severn Valley. What may be found to the north-east has
yet to be learnt; but a preliminary survey gives little hope of any
strata being found to fill the gap, or even of any other occurrence
of beds between the Notgrove Freestone and the Upper Trigonia-
grit.

The relation of the Bourguetia- and Phillipsiana-beds to the
Witchellia-grit, and thence to the Gryphite-grit, was first learnt
in the quarries east of the Rolling Bank. The details which
they afford are shown in Diagr. I, drawn to a true scale. The
shaded portions show the beds as they are exposed in the quarries,
and the continuing lines indicate the surmises which are to be
made therefrom.

The recent extension of the Rolling Bank quarry has confirmed
the sequence illustrated, but it has not enabled any better measure-
ments of actual thickness to be made than those which are possible
from this diagram.

LTV. Tuer Sequence oF CotreswoLpd ‘ InFeRion Oorrte’ Rocks.

A sequential list of certain Cotteswold deposits is given in the
paper on Dundry Hill,’ together with the dates assignable to each
according to a chronological system. There have now to be recorded
certain additions and emendations, so that the following sequence
is presented :—

CHRONOLOGICAL TERMS, STRATIGRAPHICAL TERMS.
Batuonian. Garantiane. Upper Trigonia-grit.
(Non-sequence.) §=——_________
Sauzei. Phillipsiana-beds.
fd ba ctiay
Witchellie. itchellia-beds.
Basoctan. Notgrove Freestone.
| Sonninie. Gryphite-grit.
Buckmani-grit.
Discite. Lower Trigonia-grit.
Concavi. Snowshill Clay.
AALENIAN. Harford Sands.
Bradfordensis. | Upper Freestone.

1 «Mid-Cotteswolds,’ p. 410. 2 Ibid. p. 423.
> Quart. Journ. Geol. Soc. vol. lii. (1896) p. 704, table vi.

Diagram II.—Hewlett’s Hill to beyond the Rolling Bank.

ot © cy
35 3 x S =)
2 a Bx) = $ 4 Poe
HILL N.E.OF- ROLLING BANK © Ot Sos
= Lhe] 2 Sls
sit “es
X 2. Os grt us
S]5 S _.ngiare” 9 CWP
sig pile ni
Rls Fault SUMMIT op DH OTE @
THE ROLLING BANK — Cong joe Fault UP uti GryestO™

erate-Fault >} pow" Ey
eA Frit ye
0. i Aig

psi" 7

pilli
QUARRIES EAST OF ROLLING BAN ee

Harfo"
EAsT oF ,
THE CAMP

SouTH WALL OF ._s
CLEEVE COMMON

NEAR
UPPER HILL FARM

Lower Freestone
and perhaps Pea Grit

Fault—————> } ag =
+X hl) AES
Tas iffs

Freestone

Freestone

1
HEWLETTS HILL 939 ————_»>

lcm. = 40 feet.]

1 inch = 1 mile.

tal

izon
Vertical

Hor

[Scale

Vol. 53.] | THE BAJOCIAN OF THE CLEEVE HILL PLATEAU. 617

Table vi., published with the Dundry paper, should be amended in
accordance with this, and then will be obtained the fullest sequence
of deposits which has been yet noticed in the Cotteswolds. It is
interesting to observe that the Cotteswold ‘Inferior Oolite’ which
was parted into three divisions by Murchison in 18347 is now
divided into 17 portions of varied lithic aspect, with particular
faunal features. Of these divisions, 14 lie beneath the Upper
Trigonia-grit; and of the 14, different localities show each their
own particular number to be present. Thus, in a south-to-north
traverse, there may be tabulated as present beneath the Upper
Trigonia-grit :

At Uley Bury, Birdlip, Leckhampton, Cleeve Hill,
2 5 10 14 divisions.

This record illustrates the difference effected mainly by denuda-
tion prior to the deposition of the Upper Trigonia-grit.

VY. CoRRELATION OF THE CreEVE Hitt Deposits WITH THOSE
OF OTHER LOCALITIES.

With the alterations noted above; the Cleeve Hill deposits may
be correlated with those of Dundry and Dorset-Somerset according
to the table given in the paper on Dundry Hill just quoted. Only
those slight alterations and the addition of the Snowshill Clay are
required.

VI. Tue Srrvucture oF Part or CreEve Hitt.

The approximate structure of the upper part of the Cleeve Hill
plateau, from the top of Hewlett’s Hill to the Rolling Bank quarry,
and to the knoll immediately beyond that, is illustrated in Diagr. IT.’
Not quite a straight line has been followed—or rather some details
off the line have been brought into the general line, the better to
show the sequence of the strata and their position. It may be
seen that there are seven faults noted; three of these, but one is
scarcely worthy of the name, are shown in the Rolling Bank itself.
There may be other faults hidden.

Of these faults, No. 1, near Hewlett’s Hill, is shown by old workings

1 «Geology of Cheltenham, p. 10.

2? A note may be made concerning what I have called the Nerinea-bed,
although it is outside the scope of this paper. It shows some fine Nerinee,
and it also yields a Terebratula so closely like T. fimbria that it would be called
that fossil. However, certain peculiar characters distinguish it from the
Terebratula fimbria of the Oolite Marl—it is, in fact, a biologically earlier
fossil, and is the parent of the Oolite Marl shell. The bed in which it occurs
is a fossiliferous, somewhat pisolitic, sandy vein in the Lower Freestone. I am
not at present able to say how far the bed is situated below the Oolite Marl, or
above the Pea Grit. Possibly it has been hitherto considered as Oolitte Marl.
The interest attaching to it is biological, in connexion with the fimbriate
Terebratule.

° The surface of the ground, with the approximate height shown, is such as
would be found by any one making a traverse along the hill-top from Hewlett’s
to beyond the Rolling Bank,

618 THE BAJOCIAN OF THE CLEEVE HILL PLATEAU. [ Dec. 1897.

of Harford Sand on the same level as a freestone-quarry. No. 2
can only be surmised from the stones of the field. No. 3 seems to
extend in a north-westerly direction from just before the southern
entrance to Cleeve Common (by Upper Hill Farm), and to be nearly
in the line of a valley-like depression, of which perhaps it may be
the cause. No. 4 is plainly shown at ‘ Roadstone Hole,’ where
the strata are tilted at an angle of about 55°. No. 7 is at the
northern end of the Rolling Bank, where the Upper T’rigonia- and
Clypeus-beds are let down level with beds of the Lower Freestone—
a fall of about 100 feet; this fault extends across the hill.

At the southern end of the Rolling Bank quarry, another
fault, No. 5, has lately been opened to view.’ By this fault the
Phillipsiana-beds are tilted at asteep angle against the Clypeus-grit
of the other part of the quarry; and in such a manner that, on
about this level, all the strata from the Phillipsiana-beds to the
Gryphite-grit are passed in succession in a southward direction.
But there is another feature of interest about this fault: it is
separated from the rest of the quarry by a fissure into which has
dropped a mass of vertically-bedded conglomerate. It yields the
following section :—

Ft. ins,
1, Rubble of the Clypeus-grit with some red clay, and calcareous
AHA ETAHLOMS Verem er. vssccdeconsteces Soeees ase eaemet cen ett et hs see eeeeee 6
2. Fine gravel with much red clay, the gravel not waterworn ... 1 8
3. Limestone, lumps of Clypeus-grit, and some red marl, Terebra-
tula globata, Rhynchonella hampenensis ........scesseveeececeecees 2 O

The whole is much cemented together by a calcareous deposition
from percolating rainwater.

The relationship of this section to the other beds is shown in
the diagram (IIT) facing this page. Bed No. 3 is apparently the
same as that marked No. 3 on the left—it is the top of the Clypeus-
grit. Above that, on the left, the band of red clay is particularly
noticeable, associated somewhat irregularly with fine gravel ; over
that is more rubble, of apparently the Clypeus-grit, and mixed with
that again is rubble of the Phillipsiana-beds.

The explanation, therefore, appears to be this :—The northern
portion (A) of the Rolling Bank quarry fell in after the Fullers’
Earth Clay had been removed from Cleeve Hill, and after a
relic of it—the red clay—had been worked up with some top
rubble of the Clypeus-grit, but before the Clypeus-grit had been
removed. ‘This fall caused the fissure to open, and also tilted the
beds of portion B. By this tilting the uppermost beds of portion B
slid into the fissure, while the Clypeus-, Upper Tragonia-, and part
of the Phillipsiana-grits of portion B slid over to C and perhaps
extended towards A. These beds have subsequently been removed
by the same agency as that which has removed all the Clypeus-
and Upper Trigonia-grits from Cleeve Hill, except where they have
been protected by being thus let in by a fault.

1 No. 6 is quite a small fault in the Rolling Bank.

oe

Diagram IIT.
A. C. B.

: Debris & rubble of Phillipsiana-beds

8 ened (i
Clypeus-grit. rubble
Clypeus-grit Fissure with |
Conglomerate
/ OF le B,
Clypeus-grit

Upper Trigonia-grit

Phillipsiana-beds

DIAGRAMMATIC SKETCH
OF A PORTION OF*THE

Bourguetia-beds ROLLING BANK QUARRY

SHOWING
THE FISSURE: OF CONGLOMERATE

The sketch zs not to any scale.

§20 THE BAJOCIAN OF THE CLEEVE HILL PLATEAU. [| Dec. 1897.

VII. Tae Basocran DENUDATION.

The presence of the Phillipsiana- and Bourguetia-beds at the
Cleeve Hill plateau supplies certain further details concerning the
Bajocian denudation : namely, that at Cleeve Hill there was spared
an additional amount of about 45 feet of strata more than at
Leckhampton. That hill again has about 34 feet more than at
Cranham (Buckholt) Wood, beyond Birdlip. Therefore, in com-
parison with that locality, Cleeve Hill shows about 79 more feet
of rock beneath the Upper Zrigonza-grit; and, as the distance is
about 9 miles, the average fall, or amount removed, is about 9 feet
per mile. This amount of fall would be so small a departure from
the horizontal that it can be easily understood how the Upper
Trigonia-grit was laid down upon different rocks with a false
appearance ot conformity to each of them. A view of the Bajocian
denudation, and the position of the Upper Trigonia-grit relatively
to underlying beds from beyond Birdlip to Cleeve Hill, is shown
in Diagr. IV, facing this page. In this diagram the almost regular
line of the Bajocian denudation should be noted.’

With regard to the bed which underlies the Upper Trigonza-grit,
it should be remarked that whether freestone, sandstone, or other-
wise, it is always considerably bored, that the shells which the bed ©
contains are bored, that the top of the bed is more or less planed
off, and that oysters are frequently found forming a thin layer on
this planed top.

The fact that at Cleeve Hill as at Dundry,” and at Sandford
Lane near Sherborne, the denudation occurs on the top of beds
which can be dated as Sauzei hemera is a matter of some interest
in connexion with the treatise which Dr. M. Vatek wrote to show
that the greatest stratigraphical non-sequence was between strata of
the Murchisone- and Sowerbyi-zones,’ and that therefore that was the
proper place for a division between Lias and Oolite. These localities
- do not accord therewith, and still less does Oborne in Dorset, where
a non-sequence is not found. But the fact is that no stratigraphical
details can decide a matter of geological division—such phenomena
are local, and they are not contemporaneous. The only method
by which an uniform geological system of division, universally
applicable, can be accomplished is by making it dependent on
paleontological, and independent of stratigraphical matters.

1 At Leckhampton Hill the Upper Freestone has a planed-off top surface,
is somewhat bored, and has pitlike excavations which are filled with Snowshill
Clay. ‘There are no Harford Sands. In the Stroud area the Upper Freestone
is much bored, so that from Leckhampton southward there was an Aalenian
denudation of the Upper Freestone. See also ‘ Mid-Cotteswolds,’ p. 480,
table vi. ;

2 ¢Dundry Hill,’ Quart. Journ. Geol. Soc. vol. lii. (1896) p. 704, table vi., &
p- 711. :

3 ‘Ueber die Fauna der Oolithe von Cap St. Vigilio, verbunden mit einer
Studie tiber die obere Liasgrenze, pt. ii.’ Abh. k.-k. geol. Reichsanst., vol. xii.
(1886) pp. 120-209.

. <—————_CRANHAM WooD

Diagram IV.—The Bajocian Denudation: Birdlip to Cleeve Hill.

CLEEVE HILL

T.Phillipsiana bed

HAMPTON HILL

ECK

<————Cuckoo PEN,
—<—_——TUFFLEY’S

—<—Bmoip

Terebratula Buckmani-grit

a ee, 7
Lower Trigonia-grit

Harford Sands Snowhill Clay

Upper Freestone Upper Freestone

Scale: Horizontal, 15 mm. or ‘6 inch=1 mile, Vertical, 1 mm.=2 feet.

[For ‘Snowhill Clay ’ read ‘ Snowshill Olay.’]

ee

622 MR. S. 8. BUCKMAN ON THE BAJOCIAN [Dec. 1897,

A map (Pl. XLVI)has been constructed to show over what portions
of Cotteswold country the Upper Trigonia-grit comes into actual
contact with particular rocks. The lines which are drawn upon
the map give, so far as evidence and justifiable supposition may
indicate, the limits of each particular rock, so that the lowest
boundary-line defines where the last trace of a particular bed is
found beneath the Upper Trigonia-grit. It will be seen that with
a little exception, in passing from west to east, the Upper Trigonia-
grit rests successively upon the strata from the Phillipsiana-beds
to the Oolite Marl’—the outer line marking what is presumed to
be the extreme boundary of the Oolite Marl.

The reasons which have led to the drawing of the boundary-lines
in the present positions may be briefly stated as follows :-—

1. Direct evidence, furnished by actual exposures.

2. Indirect evidence, such as may be obtained by constructing

diagrams from the exposures of various localities (see
Diagr. IV of this paper, p. 621, and that given in ‘The
Bajocian of the Mid-Cotteswolds,’ Quart. Journ. Geol. Soc.
vol. li. 1895, p. 430, table vi).

3. Inference,—that there would be more or less of a parallelism
between the courses of the different lines, so that an un-
known contour of one may be approximately determined
from a known contour of another.

1. The direct evidence speaks for itself; and the actual
exposures are marked in the map, with the name of the bed upon
which the Upper Trigonia-grit rests, except in certain cases enclosed
in brackets where the actual contact has not been recorded, as, for
example, Edgeworth. The actual exposures observed are recorded
upon my own authority ; but the following notes have also been
considered ; they are recorded in the map in inverted commas :—

1857. Lycerr, ‘ Cotteswold Hills. Thin band of Oolite Marl
beneath upper ragstones at Ball’s Green, near Nailsworth, p. 50.

1857. Hutt, ‘Geology of the Country round Cheltenham.’
Ragstone on Oolite Marl, Turkdean, p. 38. Ragstone on Freestone,
5 feet from Upper Lias at Sherborne, p. 40. Ragstone on Upper
Lias at Stow, Rissington, and Burford, pp. 40 and 47. Oolite Marl
at Condicote, p. 37.

1870. J.H.Tacnron. Sapperton Tunnel; Proc. Cotteswold Nat.
Field Club, vol. v. p. 268,—records the find of Terebratula fimbria.

1894. H.B.Woopwarp, ‘ Lower Oolitic Rocks of England,’ Mem.
Geol. Sury.: Jurassic Rocks, vol. iv. Oolite Marl at Yanworth
Common, p.127; Harford Sands at Bourton Clump, p. 143; Gryphite-
grit [? Lower 7rigonia-grit| and Harford Sands, east of Stanway
Hill Barn, p. 137; Oolite Marl west of Blockley, p. 141.

C. Upton, information ;—Upper Trigonia-grit on Oolite Marl by
roadside near Long Wood, between Selsley and Nympsfield.

1 It also rests on lower rocks; but their limits have not been attempted in
the present case.

Vol. 53.] DEPOSITS OF THE CLEEVE HILL PLATEAU. 623

2. Indirect evidence. Not all the possible sections which might
be constructed have been examined; but, as an instance, the
course of the Wvrtchellia-grit-line towards Cheltenham may be
quoted. This is on the evidence of the section from Leckhampton
to Cleeve.

3. Inference. The south-easterly extension of the Witchellia-
grit-line is based on the idea of parallelism with the known ex-
tension of Notgrove Freestone. The north-easterly curvature of
the Oolite-Marl line towards Birdlip is based partly on the same
idea of parallelism, partly on the fact that the Upper Trigonia-grit
is close to the Terebratula fimbria-line at Cranham Wood and at
Bull Bank, by Miserden.

The assumed courses across the vale are shown by dotted lines,"
but all the lines on the map are to be regarded as approximative.
Further exploration of the country will no doubt show the necessity
for some modification of the lines, and considering the nature
of the task, with the difficulty of finding suitable exposures, this
may be reasonably expected. Such alteration in the matter of details
will not, however, be really important, in regard to the general view
which the map affords of the distribution of the rocks upon which
the Upper Trigonia-grit rests. It may be confessed that the line
which is most speculative is the boundary-line of the Oolite Marl;
but the evidence upon which it is drawn is given in the map.

The attempt to construct this map shows how very much there
is yet to be learnt concerning the geology of the Cotteswolds.
Particularly is this the case with the large stretch of country
north-east of Cleeve Hill and north of the Banbury & Cheltenham
Railway. Of this country we have very few details—practically
no more than an outline. For this reason I could make no attempt
to map it with reference to the Bajocian denudation. But probably
another reason will prevent any such map from being constructed
in detail, and that is the greater removal of the Upper Trigonia-
grit by recent denudation—the farther north they are the more
have the ‘ upper beds’ suffered.

VIII. Denvupation anp OVERLAP.

A noticeable distinction may be drawn between the cause of the
absence of the lower Ragstones—the Lower Trigonia- and Gryphite-
erits—from the Birdlip district, and the absence of the Harford
Sands and Snowshill Clay south of Leckhampton. The former is
due to denudation, the latter is due to absence of deposit. In the
former case, coming either from north or south towards Birdlip it is
found that always the upper stratum is removed while the surface
of the bed which may be present exhibits borings and signs of
erosion. This is illustrated in the following diagram :—

’ The irregular line deaotes the edge of the Cotteswold escarpment.

624 MR. S. 8. BUCKMAN ON THE BAJOCIAN (Dee. 1897,

Diagram V.
S. -Birdlip. N.

Gryphite-grit. Gry phite-grit.

Lower Trigonia-grit. Lower Trigonia-grit.

Upper Freestone.

In the latter case the bored surface is underneath, for there was
an Aalenian denudation of the Upper Freestone; and the lower
stratum is found to fail while the upper one continues. Hence an
upper bed overlaps a lower one, as the Harford Sands are
found at Cleeve, with the other deposits, but only a thin bed of
Snowshill Clay is found at Leckhampton ; while neither are present
to the south. So the case stands thus :—

Diagram VI.

s. N.
Leckhampton. Cleeve Hill.

Low

=-

Snowshil! Oe:
Harford Sands.

Bored surface.

Upper Freestone. Upper Freestone.

This difference, in connexion with any absence of deposits, requires
to be carefully noted.

IX. A WaATER-RETAINING BED.

It is generally taught that between the Fullers’ Earth above and
the Upper Lias below there is no impervious or water-retaining
deposit. Exception must be taken to this statement in several cases;
but it is particularly incorrect with regard to the Northern Cottes-
wolds. The Snowshill Clay is an impervious bed; and its position
lies about the middle of what is indefinitely called ‘ Inferior
Oolite.’ In a district where water is obtainable only with difficulty

Wels 3. | DEPOSITS OF THE CLEEVE HILL PLATEAU. 625

the Snowshill Clay becomes of considerable economic importance.
Its presence has governed the situation of farmhouses and cottages.

The Snowshill Clay is the bed which throws off water for a
cottage just north of Puckham Farm, and the water from this
spring is taken to the farm itself, although that farm is situated
not very far above ‘ Upper Lias.’ The Clay also throws off water
for the gamekeeper’s cottage immediately west of Puckham Wood.
Moreover it furnishes the sole water-supply for Wontley Farm.
All these places are on the Cleeve Hill plateau, and the supply is
said to be constant.

At the Seven Wells, about 13 mile south of the Fish Inn,
Broadway, and about the same distance north-eastward of Snows-
hill, there are copious springs of water thrown out by the Snowshill
Clay, used for the supply of the farmhouse. These ‘Seven Wells’
are said never to have failed, and the people of the locality claim them
as ‘the source of the Thames,’ Mr. H. B. Woodward! apparently
considers that these springs issue from the Upper Lias; but there is
in the field below them a quarry of sand, which would be in
the position of the Harford Sands, and this again accords with the
general lie of the beds in the district round.

No doubt many other farms in the Northern Cotteswolds owe their
water-supply to the impervious character of the Snowshill Clay.

X. Ancrent GEOGRAPHY OF THE CLEEVE Hitt PLATEAv.

There are many dry valleys intersecting the Cleeve Hill plateau.
Some of them point to a time when the plateau was covered by an
impervious bed of Fullers’ Earth Clay, upon which reposed perhaps
a portion of the Great Oolite; the valleys were excavated by
streams thrown off by the Clay.» When the capping of Fullers’
Earth Clay was removed these valleys became dry. Others, how-
ever, may have become only partially dry then, because streams
may have issued from the top of the Snowshill Clay. But the
Snowshill Clay has in its turn been removed, and then the valleys
became dry down to the outcrop of the Upper Lias.’

On Sevenhampton Common a stream issues from the top of Fullers
Earth Clay from beneath Great Oolite. Several of the dry valleys
above Whittington commence just about where Fullers’ Karth Clay
would be if it were present, and so they may have been excavated by

?

1 ‘Tower Oolitic Rocks of England, Mem, Geol. Surv.: Jurassic Rocks,

vol. iv. (1894) p. 504.

2 E. Witchell, ‘On the Denudation of the Cotteswolds, Proc. Cottesw.
Nat. Field Club, vol. iv. (1868) p. 227.

3 With a rainfall of very much greater magnitude—beyond the absorption-
power of the most pervious Cotteswold strata—the idea of a former clay-
capping may not be necessary. Then the rain would flow as surface-water off
the water-logged pervious strata, and in so doing would cut channels, which
would in time become valleys—much on the same principle as the channels
cut in a wide gravelled courtyard by heavy rain at the present day. This
surmise would fit in with the idea that the flat top of the Cotteswoldsisa
line of marine denudation.

Q.J.G.8. No, 212. 27

626 MR. S, S. BUCKMAN ON THE BAJOCIAN (Dec. 1897,

streams thrown out by a former capping of that clay. At Wontley
Farm there is a noticeable dry valley, and the portion of it above
the Snowshill Clay may have been excavated by a stream from the
Fullers’ Earth. Here, too,is found a spring from the Snowshill Clay ;
but with the present rainfall, some 27 inches per annum, there is
not sufficient water to form a stream down the valley: it becomes
lost. But no doubt the rainfall was very much greater when the
Cotteswolds were—as the name implies—a great wooded tract of
country.’

The large size of the Cotteswold valleys in proportion to the
streams which flow down them is generally very noticeable. To
account for the size of the valleys requires two suppositions—a more
extensive drainage-area, and a greater rainfall. In many cases the
former may be granted readily, in some cases it cannot be: the
greater rainfall is then the conclusion arrived at. It may be
doubtful whether a more arboreal character would, in a climate like
the present, increase the rainfall suificiently, though it might make
much difference. Of course a far more humid climate may also be
surmised—the so-called ‘ Pluvial Period.’

Decrease of rainfall must be considered in connexion with any
denudation of an impervious stratum: because, with a decreasing
rainfall, a valley would become dry very much sooner in relation to
the amount of denudation—that is, it would become dry while there
still remained of the impervious stratum much more than if the
rainfall were greater. In other words, with a greater rainfall
more of the impervious stratum would have to be removed before
the spring dried up. Valleys which are now dry, but have been
excavated by streams issuing from a former clay-capping, are a
common feature of the Cotteswolds.

However, the interest which attaches to the Cleeve Hill examples,
particularly to the valleys leading to Postlip, is the depth to which
they have been excavated, owing to the rapid fall of the streams
from the top of the hill into the valley of the Severn. Yet we must
assume that the streams which originally excavated the Postlip
valleys did not flow into the Severn, but formed part of the
drainage of the Thames. The shape of the Cleeve Hill plateau
at Corndean, and by Wadfield Farm, gives evidence of this; and,
further, the Sevenhampton valley must have been excavated by a
strearn which came from the north, from a former extension of
the Cotteswold plateau over the country beyond Winchcombe and
Toddington : it was a tributary of the Coln. The Postlip streams
would have been tributaries of the Sevenhampton stream.

Further, the valley which is at the southern end of the Cleeve Hill

plateau—part of which is now the valley of the Chelt—must have
been also excavated by a stream tributary to the Coln. It flowed

1 Cotteswold, Coed, a wood (Welsh) ; wold, a wood (Anglo-Saxon). But I
would suggest that the Anglo-Saxon name is a corruption of an older Welsh
name, like, say, Coed-y-swil=the wood of the plain. Sw is ‘a flat space,’ and
the flat, plain-like appearance of the top of the Cotteswolds is very noticeable.
The native pronunciation is ‘ Cot-sul.’

Vol. 53. ] _ DEPOSITS OF THE CLEEVE HILL PLATEAU. 627

eastward from a former westerly extension of the Cotteswolds.
The 700-foot contour-line of the Chelt Valley supports this idea.’
It may be further surmised that the western escarpment of the
Cleeve Hill plateau formed one side of a river-valley along which
this stream flowed.”

All this, of course, was at a period when the Cotteswolds had a
much greater extension over the valleys of the Severn and the
Warwickshire Avon. At that time the Thames must have been
not only a far larger, but a very much longer river than it is now.

XI. Map or tHe Creeve Hist Prateav.

With this communication is presented a map of the district
referred to. No attempt has been made to map the limits of the
various deposits, because, owing to the faults, this must be a work
of some labour. The map, however, is given as a guide toa dis-
trict wherein it is difficult to state with exactness the sites of the
exposures. The beds shown by the different exposures—or at least
by the principal quarries—are marked upon the map; and besides
that, where other evidence of the nature of the substratum has been
obtained, the name of the deposit has been entered. Some of the
faults have also been indicated. (See p. 628.)

XII. Conctusion anp SUMMARY.

This paper deals with a part of the Northern Cotteswolds, and
it is hoped to supplement it in the future by some account of the
remaining portion of that little-known district. The present com-
munication deals only with some of the rocks exposed at the Cleeve
Hill plateau’; but it treats of that portion about which most mis-
apprehension has occurred, and whose position in the series it has been
always a very difficult point to determine. The work in the Mid-
Cotteswolds, and particularly the recognition of the position of the
Witchellia-grit at Cold Comfort, gave the necessary clue to the
unravelling of the Cleeve Hill sequence. The interesting point is
that at Cleeve Hill there should be found so much more rock
beneath the Upper Trigonia-grit. There are the Phillipsiana-,
Bourguetia-, and Wzitchellia-beds, of which no trace is found at
Leckhampton ; and there is a thick deposit of Notgrove Freestone,
of which Leckhampton shows but the smallest remnant.

1 The present streams on the east and south of the Cleeve Hill plateau could
not have excavated all those valleys, because they rise from 200 to 300 feet
below the top edges thereof.

* The western side of Cleeve Hill would be analogous to the eastern side of
the Sevenhampton Valley. The latter, supposing the Cleeve Hill plateau to
be by any means removed, would become the outer Cotteswold escarpment, and
would be the relic of an old river-valley.

3 Much has yet to be learnt about the others, especially concerning the
Pea-grit series.

27 2

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Vol. 53.| | THE BAJOCIAN OF THE CLEEVE HILL PLATEAU. 629

There are, however, additional matters of interest; meanwhile
the following summary of the present paper may be given :—

1. That the lower beds of the northern part of the Rolling Bank

quarry overlie the Witchellia-grit.

2. That these deposits of about 20 feet in thickness, with their
lithic and faunal differences, may be conveniently distinguished
as Terebratula Phillipsiana- and Bourguetia-beds.

. That these beds may be approximately dated as Sauzei hemera.

. That these beds have not been found beyond the Cleeve Hill
plateau.

. That the Upper Trigonia-grit lies non-sequentially upon these
beds.

. That a distinct clay-deposit may be recognized at Cleeve Hill,
separating the Lower 7rigonia-grit and the Harford Sands ;
and that it may be named Snowshill Clay.

7. That this deposit is more developed in the farther Northern
Cotteswolds; that it is a water-retaining bed even on the
Cleeve Hill plateau, and that it is, therefore, a stratum of
economic importance.

8. Further facts concerning the Bajocian denudation are set forth ;
and a map (Pl. XLVI) is given showing the area of the different
deposits upon which Upper Trigonia-grit was laid down.

9. Some notes on the ancient geography of Cleeve Hill, especially
in regard to its old lines of drainage, are presented.

10. A sketch-map of the principal portion of the Cleeve Hill
plateau is given. It shows the positions of the different
quarries; and the principal strata which they contain are
also marked therein.

oO Oo Boo

PLATE XLVI.

Map of the Bajocian Denudation, showing the area of the different beds
upon which the Upper Zrigonia-grit was deposited ; on the scale of 4 miles to
the inch.

Quart. Journ. Geol. Soc. Vol. LITT. Pl. XLVI.

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Quart. Journ. Geol. Soc. Vol, LIM. Pl, XLVI.

BROADWAY &

MAP OF THE
BAJOCIAN DENUDATION

shewing the area of the different beds upon which
the Upper TRIGONIA-grit was deposited.

Ti MiarfordSandi

BUSEVEN WELUS Plocktep

Downs

STANTON

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MINCHIN
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NAICSWORTH

Scale:
~Oolite Marl”

1 inch = 4 miles.

OvopEW

GENERAL INDEX

TO

THE QUARTERLY JOURNAL

AND

PROCEEDINGS OF THE GEOLOGICAL SOCIETY.

Ab-Araga Wells (Nubia), granite N.
of, 862; chem. anal. of water of,
374, 375.

Aspsott, W. J. L., Lyell Fund Award
to, xliv.

Abergele (Flint), drift near, 344.

Abu Sinaiyat (Nubia), igneous rocks
from, 364 e segg.; vein-quartz
from, 370.

Actinozoa of Keisley Limest., 83, 93 ;

* of Portraine inlier, 529, 538.

AXolian origin of subrecent concrete
of Cutch, 227 et segg., 243, 244.
See also Wind-action.

Afghan-Baluchistan frontier, vole. &
other rocks from, 289-309 figs. &
pls. xviii-xx (map & microse. sec-
tions).

Africa (South), oceurr. of Sigillaria,
Glossopteris, etc. in Trias of, 310-
314 figs. ; assoc. of Sigillaria & Glos-
sopteris in, 315-340 figs. & pls. xxi-
xxiv; classif. of rocks in, 314.

Alluvium of Cutch, 238.

Ambulacra, char. of,in Echinothuride,
115.

America (Central), Izalco & other
volcanoes in, 221.

Ammonites fr. Infr. Oolite of Skye
exhibited, iii.

Ammonites {| Cadoceras| modiolaris,
497 & pl. xxxix. figs. 7-10.

Tchefkini (?), 496 & pl.

xxxix. figs. 4-6.

[Macrocephalites| Ishme_ var.

arcticus noy., 500 & pl. xl.

_ Andesites

Ammonites |Macrocephalites| maero-
cephalus, 497 & pl. xxxix. figs. 1-3.

Amphibolite in relat. to Rauenthal
serpentine, 248 & pl. xvii.

Amygdaloidal basalts of Franz Josef
Land, 483 e¢ segg. & pl. xxxvil; do.
of Blackhead, 557; andesites of
Portraine, 521-522.

Analcime in decomp. basalt of Cape
Flora, 489.

Anatase in Grey Marl of Woodburn

fr. Baluchistan—Afghan
frontier, 295-299 & pl. xix (microse.
sections) ; of Portraine, 521-522.

Anvrews C. W., on Struct. of Skull
of Pliosaur, 177-185 figs. &
pl. xii.

Anglesey, pre-Cambr. rocks of, lxxix ;
orig. of gneisses in, 849-359 figs.

Annual General Meeting, viii.

Anodontopsis sp. (Keisley Limest.),
81 & pl. vi. fig. 9.

Anomozamites? (Franz Josef Land),
504 & pl. xii. fig. 8.

Anthophyllite fr. Koh-i-Taftan, 293 ;
in Baluchistan andesites, 298, 299
& pl. xix (microsc. sections).

Antrim Co., Cret. strata of, 540-606
w. 4 tables & pls. xliv-xlv (view
& vert. sections).

Apatite in Baluchistan andesites, 297 ;
in quartz-syenite fr. Sarlat range,
304; in Portraine andesites, 522.

Aragonite-organisms, indicators of
depth, 399,

632

‘ Arborescent’ Carb. Limest. exhibited,
xevi.

Arca sp., ef. Galliennei, 378 & pl.
xxvii. fig. 3.

—— [Barbatia] sp., ef. Geinitzi, 378
& pl. xxvii. figs. 5 & 6.

sp. (Chalk Rock), 379 & pl. xxvii.
fig. 4.

Arctica (?) eguisulcata, sp. nov., 391
& pl. xxviii. figs. 6-8.

— quadrata, 390 & pl. xxvii. fig.
25, pl. xxvii, fie A.

Arion ater in Newbury shell-mazrl,
436.

Armstrong, W., obituary of, lxiv.

Artara (Cutch), infratrappean grits
of, 235, 236.

Ash-beds, volcanic, specims. fr. Baluch-
istan, 302.

Ashy conglomerates of Portraine inlier,
523, 524; limest. zbid., 530.

Asplenium cf. whitbiense, 504 & pil.
xis fie),

Aston, E., water-anal, fr. wells in
Nubian Desert 8.E. of Korosko, 374,
375.

Atrypa expansa, 71.

marginalis, (2.

Atrypina similis, sp. nov., 72 & pl. vi.
figs. 2-3.

Auditors elected, v.

Augite, in Rauenthal rocks, 252; in
Bharab Chah basalt, 301; remains
of, in diabase fr. Nubian Desert,
367; in Franz Josef Land basalts,
483, 484, 493 & pl. xxxvli; in

Portraine andesites, etc, 522,
526.
Augite-andesite fr. Perumbakam,

chem. anal. of, 409; microsc. sec-
tion of same, pl. xxix. fig. 3.

Augite-diorites w. micropegmatite in
S. India, 405-419 & pl. xxix
(microsc. sections).

Augite-hornblende-andesites fr. Ba-
luchistan, 295, 298.

Avicula cf. inequivalvis, 502 & pl. xl.
fig. 4.

Be lavicoton mundus, sp. nov., 449 &
pl. xxxiil. figs. 14 & 15.

Axiolites in N. Pembroke rocks, 468,
469 & pl. xxxvi.

Baiera (?) sp. (Franz Josef Land),
495 & pl. xxxviii. fig. 10.

Bajocian deposits of Cleeve Hill, 607-
629, w. map, sections, & pl. xlvi
(map). ;

Bala (Upper) age of Keisley Limest.,
104; (& Middle) age of Portraine
beds, 538.

GENERAL INDEX.

[Dec. 1897,

Bala Limestone & Shale, overfolded,
& broken up by pressure, 528 figs.
Balcarrick Ho. (Portraine), igneous

rocks near, 526.
Ballycarry (Antrim), Cretac. near,
560.

Ballycastle (Antrim), Cretae. betw.
Cushendall and, 565.

Ballydouane Bay (Waterford), section
in cliff at E. end of, 273; ground-
plan of foreshore, W. side of, 274;
section in cliff at N.E. corner, 275;
do. in cliffs on N. & HE. sides of,
277, 285 ; sketch-map of neighbour-
hood, 284.

Ballygalley Head (Antrim), Cretac.

f, 568

of, 563.

Baluchistan-Afghan frontier, vole.
& other rocks from, 295-806, &
pls. xix—xx (microse. sections).

Baluchistan Desert, S. of Helmand
River, 289-295 figs. & pl. xviii
(map).

Bani of Cutch, deposits of, 239.

Barlow-Jameson Fund, list of recipi-
ents, xxix,

Barngs, J., exhibits fossils, v.

Barney’s Point (Antrim), Cretac. of,
560.

Basalts of Franz Josef Land, 482-490
& pl. xxxvii (microsc. sections) ;
distrib. of basalts of simil. type,
490-493 ; junct. w. Chalk in Antrim,
547, 552. See also Amygdaloidal,
Andesites, etc.

Basaltic rocks fr. Baluchistan, 301.

Batuer, F. A., Wollaston Fund
Award to, xxxix.

Battin’s Farm (Somerset), section to
North Down, 4389.

Beaches, Cretac., 565, 601; raised, of
Varanger Fiord, 147-151; do. in
Franz Josef Land, 508.

Beecuer, O. H., models of Triarthrus.
prepared by, xevi.

Belemnitella mucronata, zone of, see
White Limestone.

quadrata & vera, zone of, its
place in success., 597; table of fauna,
596, 599.

Belemnites Panderi, 498 & pl. xxxix.
figs. 11-14.

spp. (Jurass.), 501, 502.

Belfast (Antrim), Cretac. betw. Larne
and, 554-564.

Benbradagh (Derry), White Chalk
of, 566.

Bennettites Gibsonianus comp. w.
Cycadeoidea gigantea, 24, 26 et segg.

meu Is., changes of level in,

22.

Vol. 53.]

Betchworth (Surrey), granite-boulders
fr. Middle Chalk of, 213-220 figs.
& pl. xv.

Beyricu, H. E., obituary of, lv.

Bhachau (Cutch), infratrappean
grits of, 236.

Bhujia Hill (Cutch), infratrappean
grits of, 235 fig.

Bigganjargga (Norway), Palzoz.
boulder-rocks & striated sandst. at,
140 et segg. & pls. viii-x.

Bigsby Medallists, list of, xxix.

Biotite in Antrim Cretac. rocks, 570

Biotite-gneiss fr. Murrat, 364.

Biotite - hornblende - granite from
Baluchistan, 303 & pl. xx (microsc.
sections).

Birdlip (Gloucester), diagr. section to
Cleeve Hill, 621; do. at, 624.

Bituminous shales in Franz Josef
Land, 505.

Black Mountain (Antrim), Cretac. of,
550.

Blackhead (Antrim), amygdaloidal
basalt of, 557.

Brake, J. F., exhibits maps of Cutch,
ii; on Superf. Deposits in Cutch,
223-243 w. map & sections; on
Laccolites of Cutch & their Relats.
to other Igneous Masses of district
[title only], xcvii.

Blezard Mine (Ontario), igneous rocks
N. of, 54; chem. anal. of same, 56.

Bodo (Norway), shell-marl, ete. at,
150.

Bombs, volcanic, iu schalsteins of
Nassau, 109-111 w. fig.

Bonhomme (Vosges), serpentine comp. |

w. Rauenthal rock, 261 ‘& pl. xvii
(microsc. section).

Bonney, T. G., Sections nr. Summit
of Furka Pass, 16-20 w. figs. ;
exhibits microsc. section fr. Purley
Boulder, xciii.

Boschmans Fontein (Transvaal), geol.
of, 311; Glossopteris, etc. from,
330 et seqq.

Boulders fr. Bétchworth Chalk, 213-
220 figs. & pl. xv; rounded, in
pothole in Wadi Om Risha, 363 fig.

Boulder-bed below Molteno Beds, 311
et seqg.; assoc. w. subrecent con-
crete of Cutch, 230.

Boulder Clay, fr. nr. Llandulas to
S.E. of Abergele, 341; nr. Diserth
Castle, 345, 346.

‘Boulder-rock,’ Palzoz., at Biggan-
jargga, 140 & pls. viii-x.

Bourguetia-beds of Cleeve Hill, 613-
615.

GENERAL INDEX. 633

Brachiopoda of Keisley Limest.,
67, 90; fr. Portraine inlier, 537-
538. See also Atrypa, Leptena, etc.

Breccia, voleanic, nr. Sudbury, 45 w.
chem. anal.; (O.R.8S.) in Bally-
douane Bay, 272, 276.

Brecciation, fluxional, of N. Pembroke
rocks, 471 e¢ seqq.

Brendon Hills (Somerset), beds assoc.
w. Morte Slates, 442.

Brendon Hill Series, name prop., 442.

Bropis, P. B., presents portrait, ii.

Buckman, 8. S., Murchison Fund
Award to, xlii; on Bajocian De-
posits of Cleeve Hill Plateau, 607-—
629 w. map, sections, & pl. xlvi
(map).

Buil’s Lane (Newbury), section in
upper river-gravel, 425.

Buuten, R. A., exhibits ice-scratched
celt, vi.

Bunmahon (Waterford), Red Rocks
on coast near, 269-288 figs. .

Bye-laws, alteration of, vii.

Caernarvonshire, pre-Cambr. rocks of,
xxv.

Calamites (?) fr. 8S. Africa, 325 &
pl. xxii. fig. 46, 326 & pl. xxiv.
fig. 2.

Calcite in amygdaloidal basalts of
Franz Josef Land, 489.

Catuaway, C., on Orig. of Anglesey
Gneisses, 349-357 figs.

Cambrian, early, geol. & biol. history
of, lxv—xcil.

Camerella (?) Thomsoni, 73.

Carboniferous Limestone, arborescent
specim. exhibited, xcvi.

Cardiocarpus sp. (Permo-Carb.), 324
fig., 332.

Cardita cancellata, sp. nov., 390 &
pl. xxviii. figs. 2-5.

Cardium sp. ef. cenomanense, 389 &
pl. xxvii. figs. 23-24.

sp. cf. Mailleanum, 389.

— turoniense, sp. nov., 389 &
pl. xxvii. figs. 20-22.

Carn Alw (Pembroke), flow-struct.
in rocks from, 466.

Carn Gyffwy (Pembroke), diabase of,
475

Carn Meini (Pembroke), porphyrit.
diabase of, 475.

Carnlough (Antrim), Cretac. near,
564

Carnmoney Hill (Antrim), Cretac. of,
554.

Carrickfergus (Antrim), Cretac. near,
557.

CarrineTon, T., obituary of, xi.

634 GENERAL

Casewick (Lines), Pleistoc. plants
from, 463.

Casey’s Township (Transvaal), geol.
of, 311; Glossopteris, etc. from,
321, 322 et segq.

Cave Hill (Antrim), Oretac. of, 553.

Cenomanian age of Antrim beds, 542,
544, 586, 592.

Central Division, Cretac. of Co.
Antrim, 543, 548-554.

Cephalograptus defined, 188; phylo-
geny of, 210.

cometa, 204 & pl. xiii. figs. 10-

16

—— petalum, sp. nov., 206 & pl. xiii.
figs. 6-9.

Chaleopyrite of Sudbury district, 40,
51, 52.

Chalk of Co. Antrim, chem. & micro-
mineral. comp. of, 582-584 & tables
ii-iii; (Middle) of Betchworth,
granite-boulders from, 213-220 figs.
& pl.xv. See also White Chalk, etc.

Chalk Marl, resembl. of fauna to that
of Reussianum-zone, 396.

Chalk Rock, mollusca of, 377-894,
403 & pls. xxvii-xxviii; distrib.
& relats. of fauna, 394-398 ; condits.
of deposition of, 398-403 ; list of
foss. other than mollusca, 397.

Changes of level in Bermuda Is., 222.

Channel Is., pre-Cambr. rocks of,
Ixxxviil.

Cherts fr. Franz Josef Land, w. organic
remains, 507; radiolarian, 7b7d., 511.

Chlamys ternata, 382.

Chlorite in Rauenthal rocks, 248, 251
& pl. xvii, 257; in Baluchistan
lava, 300; in quartz-syenite fr.
Sarlat range, 804; in Antrim Cretac.

correl. of, 595-598: fauna of, 595.

Chloritic Sands & Sandstones of Co.
Antrim, 541, 549 e¢ segg.; seq. &
correl. of, 591-595.

Chonetes plebera, 454 & pl. xxxiii. figs.
1-2.

sarcinulata (?), 455 & pl. xxxiii.
figs. 3-5.

Christiania tenuicincta, 71.

Chrome-diopside in Franz Josef Land
basalt, 484, 488.

Cuurcu, J., obituary of, lvii.
Cladochonus (?) fr. Morte Slates, 456
& pl. xxxiii. fig. 8.
Claxheugh (Durham) section explain-

ed, xcix.
Clay-slates, Huronian, nr. Sudbury, 45,

INDEX.

Cleeve Hill (Gloucester), Bajocian of,
607-629 w. map, sections & pl. xlvi

(map).

Clwyd, Vale of (N. Wales), glacio-
marine drift in, 841-348 w. section
& pl. xxv (map).

Coal, format. of, 245.

Coal-bearing strata in Transvaal, 311
et seqq.

Colin Glen & Mountain (Antrim),
Cretac. of, 548-550; chem. &
micromineral. comp. of Yellow
Sandst. from, 574 & tables ii-iii;
vert. section, pl. xlv.

Combe (Somerset), ‘ Morte Slates’ of,
443.

‘ Concrete,’ subrecent, of Cutch, 228;
boulder-beds assoc. w. same, 230.
Cone-in-cone struct. in Franz Josef

Land rocks, 511.

Conglomerates (O. R. S.) in Ballydou-
ane Bay, 274, 275; of Kennedy’s I.
& Knockmahon, 281 ; pre-Cretace. (?)
of Jebel Raft, 362; of Portraine
inlier due to earth-movements,
531-534 figs. ; Cretac. of Co. Antrim,
chem. & micromineral. comp. of,
579.

Conites sp. (Permo-Carb.), 331 &
Div xxtintige2,

‘Contemporaneous veins’ repres. by
micropegmatite, 414, 416, 419.

Conularia sp. (Keisley Limest.), 80.

Cook’s Farm (Newbury), vert. sections
at, 428, 429.

Copper Cliff Mine (Ontario), rocks of,
44, 60, 61.

Corals, see Actinozoa.

Corbis (?) Morisoni, sp. nov., 392 &
pl. xxviii. figs. 13-14.

Cornwall, pre-Cambr. rocks of, Ixxxix.

Cotteswold Hills (Gloucester), Bajo-
cian of N. portion, 607-629 w. map,
sections & pl. xlvi (map).

Council & Officers elected, xxii.

Council Report, viii.

Craig nr. Llandulas, Boulder Clay at,
341.

Cretaceous strata off Co. Antrim,
540-606 w. 4 tables & pls. xliv—
xlv (view & vert. sections).

Crinoidea fr. Keisley Limest., 82;
fr. Morte Slates, 456.

Crow’s Glen (Antrim), Cretac. of,
550-551.

Orowther, Cape (Franz Josef Land),
plant-remains found at, 506.

Crush-conglomerates of Portraine
inlier, 531.

Crustacea rare in Chalk Rock, 397,
See also Trilobita.

[ Dec. I 89 7 4

Vol. 53.]

Crymmych (Pembroke), Lr. Llan-
deilo (?) of, 465; diabases, etc. near,
475.

Cryptographic structure of micro-
pegmatite, 408.

Crystallization, order of, in S. Indian
dyke-rocks, 406.

Cuckhamsley, mollusca fr. Chalk Rock
of, 378 et segq.

Cuddapah Traps, 405.

Currents, marine, evid. in Irish Cre-
tae., 601.

Cuspidaria caudata, 393 & pl. xxviii.
figs. 19-20.

Cutch (India), superf. deposits in,
223-244 w. map & sections ; lacco-
lites of, xevil.

Cyanite, see Kyanite.

Cybele rugosa var. attenuata, 536.

Cycadeoidea gigantea, sp. nov., 22-38
w. figs. & pls. i-v.

Cyclonema rupestre, 78.

sulciferum, "78.

Cypricardinia (?) sp. (Morte Slates),
447 & pl. xxxi. fig. 5.

Cystidea fr. Keisley Limest., 82.

Cystocidaroida, classif. of, 152.

Cythere Wrightiana, 67.

Dalmanites | Crypheus| laciniatus var.
occidentalis, 445 & pl. xxxiii. figs. 9-
13.

sp. (Morte Slates), 447 & pl. xxxi.
figs. 1-3.

DavsreEs, A., obituary of, liv.

Davison, C., on Distrib. in Space of
Access. Shocks of Gr. Japan. Earth-

quake of 1891, 1-15 w. maps; on

Pembroke Earthquakes of Aug. 1892
& Nov. 1893, 157-175 w. map &
pl. xi.

Dayia pentagonalis, sp. nov., 74 &
pl. vi. fig. 5.

De Bruyne Sound, basalt obtained in,
492 & pl. xxxvii. fig. 5.

Denudation, Bajocian, 620-623 w.
diagr. & pl. xlvi (map); conn. w.
overlap in Cleeve Hill district, 623.

Depth of deposition, evid. furnished
by Chalk Rock mollusca, 400 ; depth
of Cretac. sea in Co. Antrim, 599.

Derry Co., Cretac. of, 565-567.

Devon (North), Morte Slates & assoc.
beds in W. Somerset and, 438-462
figs. & pls. xxxi-xxxv (foss. & map).

Devonian (Lr.) age of Morte Slates
in W. Somerset, 444.

Dharwar Traps, 405.

Diabases of Prescelly Hills, 475.

st ae (?) fr. Wadi Om Nabadi,
369.

GENBRAL INDEX.

635

Diabasic rocks fr. Nubian Desert, 365-
367.

Distey, G. E., exhibits specim. of
flint, xevii.

Didymograptus cf. indentus var. nanus
fr. nr. Crymmych, 465.

Dimetian rocks in Caernarvon, lxxy.

Diorite of Anglesey, 351, 357; blocks
in grey gneiss iid., 355 fig.

Diserth Castle (Flint), section in esker
S.E. of, 345.

Dolerite, altered, fr. Nubian Desert,
364; of Prescelly Hills, 475.

Donabate (Co. Dublin), porphyrit. rock
at, 527.

Donnington Gravel, 422-425 figs.

Donnington Square (Newbury), vert.
section at, 428.

Dornine, E., obituary of, 1xii.

Downhill (Antrim), Cretac.
White Park Bay and, 568.

Draper, D., Occurr. of Sigillaria,
Glossopteris, & other Plant-remains
in Triass. Rocks of S. Africa, 310-
314 w. map & sections.

Drift, glacio-marine, of Vale of Clwyd,
341-348 w. section & pl. xxv (map);
pre-Glacial, of Newbury, 420.

Dulas River (N. Wales), gravels, etc.
of, 3438.

Dundry Hill (Somerset), deposits
correl. w. those of Cleeve Hill,
617.

Dunes in Baluchistan desert, 290 fig.,
291.

Dungiven (Derry), White Chalk of,
566.

betw.

Dust-storms in Cutch, 228, 229.

Dykes, olivine-diabase, of Sudbury
district, 62; cuttg. Chalk at Squires
Hill, 552.

Dyke-rocks of S. India, explan. of
struct. of, 409-411.

Earthquake of 1891 in Japan, distrib.
in space of access. shocks, 1-15
w. maps; in Pembroke, Aug. 1892
& Nov. 1893, 157-176 w. map
& pl. xi; earthquake-crack(?) along
Afghan frontier, 291.

Eastern Division, Cretac. of Co, An-
trim, 543, 554-565.

Echinocorys gibbus, zone of, see Chlo-
ritic Chalk.

Echinocystis, struct. of, 124 w. figs. ;
affinities of, 126.

Echinodermata of Keisley Limest.,
82, 93.

636

Kchinoidea, homologies of masticatory
pyramids & apical plates of, 131.
Echinothuride, affinities of, 112-122

w. figs. & pl. vii.

Hlevation, period of, in Brit. Cretac.,
600.

Euuzs, G. L., on Petalograptus &
Cephalograptus, 186-212 figs. &
pls. xili-xiv.

Elmwood (Franz Josef Land), view
showg. basalts, etc., 481; shales
found E. of, 495; foss., etc. found
at, 496-499 & pls. xxxvii, xxxix;
do. found W. of, 501-502 & pl. xl.

Enborne Road (Newbury), section in
gravel-pit, 426.

England, Western & Central, pre-
Cambr. rocks of, lxxxi; South of,
pre-Cambr. rocks of, lxxxviii.

Enstatite in Rauenthal rocks, 252 ;
(?) in Yellow Sandst. of Hillsport,

Epidote in Baluchistan lavas, 300;
in quartz-syenite fr. Sarlat range,
304

Eridophylium sp. (Morte Slates), 457.

Erratics assoc. w. raised beaches of
Varanger Fiord, 148. See also
Boulders, Boulder-rock, etc.

Esker 8.E. of Diserth Castle, 345 fig.

ErrinasHausen, C. von, obituary of,
lvii.

Hunema carinatum, var., 78.

EHuomphalus nitidulus (?), 79.

ef. obtusangulus, 79.

subsulcatus (?), 79.

Evenagh, Ben (Antrim), Cretac. N.
of, 567.

Exogyra conica, zone of, see Glauco-
nitic Sands.

Farnwortu, W., obituary of, lxv.

Faults & their conn. w. Pembroke
earthquakes, 172; in Cleeve Hill
Plateau, 617-619 w. diagr.; fault-
line along Afghan frontier, 291.

Favosites alveolaris, 84.

Fellows elected, 1i—vii, xciii—xcix.

Felsite of Anglesey, 350, 358 ; mica-
gneiss prod. fr. same, 351, 354.

Felsitic rocks of Kennedy’s I., 280,
281; fr. Baluchistan, 300. See also
Felstanes.

Felspars, in Baluchistan andesites,
296, 297 & pl.xx; in Bharab Chah
basalt, 301; altered, in rocks fr.
Nubian Desert, 871; in Franz
Josef Land basalts, 482, 483; in
Portraine andesites, 522, 526. See
also Oligoclase, Plagioclase, etc.

GENERAL INDEX.

[ Dec. 1897,
Felspar-porphyry in Ballydouane Bay,
273

Felspathic lavas fr. Baluchistan, 300
& pl. xx (microse. sections).

Felstones fr. Nubian Desert, 368;
brecciated, of N. Pembroke, 472,
473.

Felstone-agglomerate of N. Pembroke,
473.

Fenestella assimilis, 77.

Fieldenia [Torellia}? (Franz Josef
Land), 494 & pl. xxxviii. fig. 11.

Financial Report, xxx.

‘Fiord-mud, suggested use of term,
151.

Flaser-gabbro of Travers Mine, 59.

Flints, worked, found nr. Newbury,
427, 432 ; conn. of flints w. sponges,
603.

Flint-implements exhibited, xevi.

Flinty Hlag (Cretac.) of Kilcorig,
545.

Flora, Cape (Franz Josef Land),
basalt, etc. of, 480; foss. found N.
of, 498-495 & pl. xxxvili; vert.
section, facg. 512. See also Elm-
wood.

Flow-brecciation in Rauenthal rocks,
260; in N. Pembroke rocks, 471,
472 fig.

Flow-structure in N. Pembroke rocks,
466, 468 et seqg. & pl. xxxvi.

Foel Ervr (Pembroke), diabase of,
475.

Foel Trigarn (Pembroke), igneous
rocks of, 465, 474.

Foraminifera in Boulder Clay of Vale
of Clwyd, lists of, 342, 343, 344;
in Antrim Chalk, 545, 547, 569,
577, 581-582 et seqq.

Foreign Correspondents elected, v,
xev; list of, xxiv.

Foreign Members elected, v; new
Bye-Law concerning, vii; list of,
XXxlil.

Forth River (Antrim), Oretac. of,
551.

Fragmental igneous rocks of N. Pem-
broke, 473.

Franz Josef Land, rocks & foss. from,
477-519 figs. w. map & pls. xxxvii-
xli (microsc. sections & foss.).

Furka Pass (Switzerland), sections nr.
summit of, 16-21 figs.

Gabbro, altered, fr. Korosko district,
364; ‘granophyric, comp. w. S.
Indian augite-diorites, 411-414.

Gaerwen (Anglesey), sections deser.,
351, 353.

Vol. 53.1.

Gaisa Beds of Varanger Fiord, 137
et seqg., 143.

Gangamopteris cyclopteroides, 323 &
pl xxi. fie. 1.

Garpiner, C. I., & Reynoxps, 8. H.,
an Account of the Portraine Inlier

Garnetiferous biotite-gneiss of Wah-
napitae, 42.

Geological Survey Index Map, iii, v,
Vi, Xciii.

Gertrude, Cape (Franz Josef Land),
lignite-seams, etc. at, 503; vert.
section at, facg. 512.

Ginkgo polaris (?), 495 & pl. xxxviii.
figs. 1-3.

—— siberica (?), 495 & pl. xxxviii.
figs. 4-5.

Glacial Epoch, another poss. cause
of, 107; phenom. of Palzoz. age
in Varanger Fiord, 137-146 w.
map & pls. viii-x, 153-156; glac.
deposits zbzd., 151-153; (?) gravel
of Newbury, 422-425 figs.

Glacial Sands & Gravels, on E. side
of Vale of Clwyd, 345.

Glaciation of Sudbury district, 41.

‘Glacio-marine’ deposits of Trémsé,
etc., 150, 151; drift of Vale of
Clwyd, 341-348 w. section & pl. xxv
(map), |

Glauconite in Chalk Rock & its
bearings on condits. of deposition,
398; condits. of format. of, 588,
604.

Glauconitic Marls of Co. Antrim,

559 et segg.; chem. & micro-
mineral. comp. of, 571-572.

Glauconitic Sands of Co. Antrim,
542, 549 et segg.; chem. & micro-
mineral. comp. of, 569-571; seq. &
correl. of, 585-589.

Glenarm (Antrim),
563.

Glossopteris assoc. w. Sigillaria in S.
Africa, 315-340 figs. & pls. xxi-
xxiv; chars. of Indian & Austral.
spp., 316-318.

Browniana, 318-322 & pl. xxi.

, var. angustifolia, 321 &
pl. xxi. fig. 4a.

— — , var. indica, 320, 321 &
pl. xxi. figs, 2-3.

Glynn (Antrim), Cretac. of, 561.

Gneiss of Rauenthal in relat. to
serpentine 77d., 247; gen. char. of
same, 250; of Anglesey, orig. of,
349-359 figs.; of Murrat, 364.

Cretac. near,

GENERAL INDEX.

637

Gneiss-formation in Sudbury district,
41.

God-i-Zirreh Lake (Baluchistan), sa-
line, 291.

Gold-workings, ancient, in Wadi Om
Nabadi, 361.

Gorgonia ? (Jurass.), 498 & pl. xxxix.
fig. 15.

Gostine, A., on Izaleco & other
Volcanoes in Central America, 221.

Gosseletia Kayseri (?), 448 & pl. xxxi.
fig. 6

Govucu (Viscount), obituary of, lvii.

Gover, W., obituary of, Ixiv.

Grammysia (2?) sp. (Morte Slates),
448 & pl. xxxi. figs. 7-9.

Granite, micropegmatitic, of Onaping,
58 ; ‘younger,’ of Sudbury district,
61; of Rauenthal, 251; fr. Bharab
Chah, 303 & pl. xx (microsc.
sections); of Anglesey, 350;
mica-gneiss prod. fr. same, 351;
gran. fr. Jebel Raft, 368.

Granite-boulders from Betchworth
Chalk, 213-220 figs. & pl. xv.

Granophyric gabbros, §. Indian
augite-diorites comp. with, 411-
414.

Grant, Cape (Franz Josef Land),
vert. section betw. Cape Stephen
and, faeg. 512.

Graptolites of Portraine inlier, 523,
531.

Grauwacke, Huronian, nr. Sudbury,
46.

Gravyels & assoc. deposits at Newbury,
420-437 figs. & pl. xxx (map &
sections).

seh (Essex), Pleistoc. plants from,
464.

Green, A. H., death announced, i;
obituary of, li.

Greenham Common (Berks), section
in gravel-pit descr., 421.

Greenham Park (Berks), well-section
deser., 422.

Greensand (Upper), term misap-
plied in Antrim, 547; U. Gr. of
Colin Mt., 548; of Antrim, correl.
w. do. elsewhere, 587, 590, 591.

Greensands of Co. Antrim, reasons
for varying thickness of, 600. See
also Glauconitie Sands.

‘Greenstone-ash’ of Kennedy’s L.,
280.

Gregory, J. W., on Affinities of
Echinothuride, & on Pedinothuria,
gen. nov. & Helikodiadema, gen.
nov., 112-122 w. figs. & pl. vii; on
Echinocystis & Paleodiscus, 123-
134 w. figs. & pl. vii.

638

Grestey, W. S8., Phenom. of a New
Foss. Plant consid. w. ref. to
Orig., Comp., & Format. of Ccal-
beds [ads.], 245.

Grey Marls (Cretac.) of Co. Antrim,
542, 549 et segg.; chem. & micro-
mineral. comp. of, 572-575 & tables
li—ili.

Grits, infratrappean, of Cutch, 233.

Grit Series of Portraine inlier, 531.

Gryphite-grit of Cleeve Hill, 612.

Gulf Stream, effects of diversion of,
107.

GwINNELL, W. F., exhibits.specims., vi.

Haut, MarsHatt, obituary of, lviii.

Halleflinta in Anglesey, 351, 352,
304, 357.

Halysites catenularia, 83.

Hammerfest (Norway),
dammed lake at, 151.

Hangman Grits, 440 & pl. xxxv (map).

Harford Sands of Cleeve Hill, 610.

Harpes sp. (Portraine), 536.

Harrison, W. J., exhibits flint-imple-
ments, etc., Vv. .

HawsEns, Miss, presents her father’s
portrait, il.

Helikodiadema, gen. nov., 121 w. figs,

Heliolites dubia (?), 84.

Helmand River (Baluchistan), desert
S. of, deser., 289-295 figs. & pl.
XViil (map).

Hewlett’s Hill (Gloucester), section to
beyond Rolling Bank, 616.

Hicks, H., addresses to Medallists,
XXXVii et segg.; obituaries of de-
ceased Fellows, etc., xlix; Recent
Evid. bearg. on Geol. & Biol.
History of Early Cambr. & Pre-
Cambr. Times, lxv—xcii; on Beech-
er’s Models of Triarthrus, xevi; on
Morte Slates & Assoc. Beds in
N. Devon & W. Somerset, Pt. II.,
438-458 figs. & pls. xxxi-xxxv
(map & foss.).

Hillsport (Antrim), Cretac. of, 559;
chem. & micromineral. comp. of
Yellow Sandst. from, 573 & tables

er eee

moraine-

xiii.

Houtanp, T. H., on Augite-diorites w.
Micropegmatite in 8. India, 405-
419 & pl. xxix (microsc. sections).

‘ Holocene’ deposits of Kennet Valley,
mollusca from, 434.

Holopea concinna, 78.

striatella, 78.

Homalonotus sp. (Morte Slates), 447 &
pl. xxxi. Hes:

GENERAL INDEX.

[ Dec. 1897,

Hooker I. (Franz Josef Land), flints,
etc. found on, 507

Hornblende, ‘migration’ of, 50;
lustre-mottled, in diabasie rocks fr.
Nubian Desert, 365; in Rauenthal
rocks, 251 & pl. xvii.

Hornblende-andesite of Koh-i-Taftan,
293; of Baluchistan, 295, 299;
corroded by quartz, 303 & pl. xx.

Hornblende-diabases fr. Nubian De-
sert, 365, 366.

Hornblende-porphyry, micropegma-
titic, of Onaping, 57.

Hornblende-schists, w. quartz-inclu-
sions, in Sudbury district, 60.

Hornblendite fr. Abu Sinaiyat, 364.

Howartn,O.H., exhibits rock-specims.
fr. Mexico & Nevada, xcy.

Hup.usston, W. H., Wollaston Medal
awarded to, xxxvii.

Hutt, E., on Another Poss. Cause of
Glacial Epoch, 107 [ads.].

Hullite comp. w. palagonite of Cape
Flora, 485 chem. anal., 486.

Hume, W. F., on Cretac. of Co.
Antrim, 540-606 w. 4 tables &
pls. xliv—xlv (view & vert. sections).

Huronian rocks of Sudbury district,

43.
Hyattella Portlockiana, 75.
Hyolithus triangularis (?), 81.

Igneous rocks in N. Pembroke, 465-
476 w. fig. & pl. xxxvi (microsc.
sections); at N. end of Portraine
inlier, 521-525; do. at S. end of
same, 525-527. See also Diabase,
Dolerite, Granite, etc.

Ilfracombe Beds, junct. w. ‘ Morte
Slates’ in Treborough district, 440.

Llienus Bowmani, 536.

oblongatus, 536.

‘Immigrated hornblende,’ 50.

India (Southern), augite-diorites w.
micropegmatite in, 405-419 & pl.
Xxix (microsc. sections).

‘Inferior Oolite’ rocks, seq. in Cottes-
wolds, 615-617.

Infratrappean grits of Cutch, 233-236.

‘ Injection-schists’ in Anglesey, 353-
307.

Inoceramus, interprismatic silicif. of
test, 556, 581, 583.

Brongniarti, 380.

Crispi-band, chem. & micro-

mineral. comp. of, 575.

striatus, 381 & pl. xxvii. fig. 13.

—— sp. (Chalk Rock), 381 & pl. xxvii.
figs. 14-17.

Insular Division, Cretac. of Co. An-
trim, 548, 565-567.

el. 53. ]

Interprismatic silicif. of Znoceramus-
tests, 556, 581, 583.

Investments, Bye-Law regarding, vii.

Ireland, pre-Cambr. rocks of, xe.

Iron-ore in Rauenthal rocks, 252,
254; in Amir Chah basalt, 301,
302; in Franz Josef Land basalts,
484 & pl. xxxviil; in Portraine an-
desites, 522,526. See also Limonite,
Magnetite, etc.

Islandmagee (Antrim), Cretac. of,
5957, 560.

Tsoseismal lines of Pembroke earth-
quake, 169.

Izalco (San Salvador), 221.

JACKSON-HarmswortH Expedition,
rocks & foss. coll. in Franz Josef
Land by, 477-519 figs. w. map &
pls. xxxvii-xli (microse. sections &
foss.).

Jan Mayen rocks comp. w. those of
Franz Josef Land, 492.

Japanese earthquake of 1891, distrib.
in space of access. shocks, 1-15 w.
maps.

Jaspers in Portraine andesites, 522,
523.

Jaulikerai (Madras), augite-diorite
from, 417 & pl. xxix. figs. 4-5.

Jebel Raft (Nubia), rocks of, 361, 362,
366, 368.

Jupp, J. W., exhibits part of Purley
Boulder, xcilii.

Jurassic limest. in Furka Pass, 17 e¢
segg.; (Upper), plants in Franz
Josef Land, 495. See also Oolitic,
Oxfordian, etc.

Kageritbar (Nubia), pseudomorph.
limonite from, 370.

Karlbotn (Norway), 149.

Kayser, E., on Vole. Bombs in Schal-
steins of Nassau, 109 w. fig.

Keady Hill (Derry), White Chalk of,
566.

Keisley Limestone, fauna of, 67-105
& pl. vi.

Kellaways Rock cephalopoda fr. Franz
Josef Land, 497, 498.
Kennarp, A. 8., on Mollusca fr.
Kennet Valley Deposits, 434-436.
Kennedy's I. (Waterford), section
of W. face, 279; ground-plan of
foreshore on H. side, 280; sketch-
map of, 283.

Kennet Valley deposits, mollusca from,
434-436.

Keuper Marls overlain by Chalk at
Kilcorig, 546; do. at Sheve Gallion,
566; seen in Colin Glen, 548.

GENERAL INDEX,

639

Kilcorig (Antrim), COretac. betw.
Magheralin and, 545-547.

Kildare Limestone foss., spp. occurr.
in Keisley Limest., 85, 97.

Knockmahon (Waterford), O.R. 8.
conglomerates, ete. at, 281.

Knorria (?) found at Zwart Koppies,
313, 315.

Koh-i-Malik Siah (Baluchistan), list
of rocks from, 306.

Koh-i-Sultan (Baluchistan), struct. of
mts., 293; ochres, etc., from, 305.
Koh-i-Taftan (Persia), an active vol-

cano, 292.

Korosko (Nubia), geol. of portion of
desert S.H. of, 860-376 & pl. xxvi
(map).

Kotae (Cutch), section W. of, 281.

Kyanite in Antrim Cretac. rocks, 572

Labradorite (?) in Baluchistan lava,
300 & pl. xx; in Franz Josef Land
basalts, 483, 488 ; in Portraine lavas,
526.

Laccolites of Cutch, xcevii.

Lacustrine deposits of Newbury, 430-
432 fig.

Lambourne (Berks), section in ry.-
cuttg., 424.

Lamellibranchiata, distrib. in Chalk
Rock, table facg. 394. See also
Anodontopsis, Arca, ete.

Langley Marsh (Somerset), fault thro’,
442

Larne (Antrim), Cretac. of, 562.
Laterite of Cutch, 236.

- Lava, depth of source of, xciv ; lavas,

felspathic, fr. Baluchistan, 300 &
pl. xix (microsc. sections); altered,
of Portraine, 526.
Leckhampton Hill (Gloucester), diagr.
sections to Cleeve Hill, 621, 624.
Lepidodendron (?) found at Zwart
Koppies, 313, 315,

Leptena rhomboidalis, 70.

Leptena-Limestone foss., spp. occurr.
in Keisley Limest., 97.

Level, changes of, in Bermuda Is.,
222.

Library, lists of Donors to, xii.

Library & Museum Committee Re-
port, xi.

Lignite at Cape Gertrude, etc., 503,
905, 507.

Tima granosa, 383.

| Acesta ?] subabrupta, 385.

[| Plagiostoma] Hoperi, 383.

Limestone fr. Murrat, 369.

Limestone Series of Portraine inlier,
527-530 figs.

640

Limonite in Amir Chah basalt, 301,
302; pseudomorph., fr. Kageritbar,

370; in Antrim Cretac. rocks, 572,

et segqg., & tables 11-111.

Limopsis sp. (Chalk Rock), 379 &
pl. xxvii. figs. 7 & 8.

Limoptera semiradiata,449 & pl. xxxiv.
figs. 1 & 2.

Lingula (?) sp. (Keisley Limest.), 68.

Liopleurodon ferox assigned to Plio-
saurus, 177.

Lizard serpentines comp. w. Rauenthal
rock, 263, 264 w. chem. anal.

Llandeilo, Lr. (?), of Crymmych, 465.

Llandulas (N. Wales), Boulder Clay
at, 341, 342 w. list of forams.

Llangaffo (Anglesey) sections in ry.-
cuttg. descr. & fig., 353 et seqq.

Losxey, J. L., on Depth of Source of
Lava [title ony], xciv.

Lomas, J., Lyell Fund Award to, xlvi.

Longmynd rocks, assoc. w. pre-Cambr.,
lxvii.

Loxonema striatissimum, 78 & pl. vi.

Lyell Medal & Fund, list of recipients,
XXViil.

Lyons, G. H., Field-geol. of Portion
of Nubian Desert 8.E. of Korosko,
360-363 & pl. xxvi (map).

Meeskelvy ravine (Norway), 139.
Maestrichtien=upper part of White
Limest. in Antrim, 544.
Maggies Mine (‘Transyaal), coal-
bearing strata at, 311.
Maghaberry (Antrim),
stone (7) at, 547.
Magherafelt (Derry), Cretac. of, 565.
Magheralin (Antrim), Oretac. betw.
Kilcorig and, 545-547.
Magheramorne (Antrim), Cretac. of,
561; chem. & micromineral. comp.
of White Limest. from, 578 &

oe eee

mulatto-

Magnetite in Baluchistan andesites,
297; in Amir Chah basalt, 301;
in Franz Josef Land basalts, 484
& pl. xxxvii, 488; in Portraine
andesites, etc., 522, 526.

Malacolite (?) in altered diabase, 365.

Malik Ainak & Dokhand (Baluchistan),
306.

Malvern Hills, pre-Cambr. of, lxxxi.

Malvern schists comp. w. Anglesey
do., 358, 356.

Man, I. of, crush-conglom. comp. w.
Portraine conglom., 535.

Marble of Furka Pass, 16, 17 e¢ segq.

Marcasite, sce Pyrites.

Marine currents, evid. in Irish Cretac.,

601.

GENERAL INDEX.

[Dee 1897,

Martesia (?) rotunda, 393 & pl. xxviii.
figs. 15-18.

McManoy, A. H., on Baluchistan De-
sert S. of Helmand River, 289-
295 figs. & pl. xviii (map).

McManon, C. A., Petrol. Notes on
Rocks fr. Baluchistan- Afghan fron-
tier, 295-306 & pls. xix-xx (microse.
sections).

Menevian Beds, occurr. of fauna in,
lxvii.

Merionethshire, pre-Cambr. in, lxxx.

Metamorphism, products of, in Angle-
sey, 301-357 figs.

Mica, see Biotite, Muscovite.

Mica-andesites fr. Baluchistan, 295,
299.

Mica-gneiss prod. fr. granite & felsite,
351.

Mica-peridotite fr. Kentucky, chem.
anal. of, 265.

Mica-schists, Huronian, nr. Sudbury,
44,

Micromiarolitic structure of micro-
pegmatite, 411.

Micropegmatitic rocks in Sudbury
district, 46, 57, 58; augite-diorites
in §. India, 405-419 & pl. xxix
(microsc. sections).

‘Migration’ of hornblende, 50.

Mill Bay (Antrim), Cretac. of, 560.

Mino-Owari (Japan) earthquake,
distrib. in space of accessory shocks,
1-15 w. maps.

Modiola Cotte, 380 & pl. xxvii. figs.
9-12.

Modiolopsis (?) sp. (Keisley Limest.),
82.

Mesk Fiord (Norway), 137.

Mollusca of Keisley Limest., 77, 92;
of Chalk Rock, 377-404 & pls.
XxVil-xxviili; fr. Kennet Valley
deposits, 434-436; fr. Portraine
inlier, 537, 538.

Molteno Beds of Transvaal, foss. plants
in, 311 e¢ segg.

Moncton, H. W., exhibits photo-
graphs, ii; elected Auditor, v.

Moneymore (Derry), Cretac. of, 565.

Monoclinic pyroxene, chem. anal. of,
407.

Morte Slates & assoc. beds in N. Devon
& W. Somerset, 438-462 figs. & pls.
Xxxi-xxxv (map & foss.).

Mulatto-stone of Magheralin, Magha-
berry, & Kilcorig, 546, 547.

Miu.uuer, F. von, obituary of, lxii.

Murchison Medal & Fund, list of
recipients, xxvii.

Murchisonia, sp. nov. ?( Keisley
Limest.), 80 & pl. vi.

Wok: 53-]

Murlough Bay (Antrim), junct. of
Cretac. w. Trias in, 565 & pl. xliv;
chem. & micromineral. comp. of
Cretac. rocks from, 579-584 & tables
ii-ili.

Murrat Wells (Nubia), geol. of country
nr., 361; igneous rocks from, 364 e¢
segq.; limest. from, 369 ; chem. anal.
of water of, 374, 375.

Murray Mines (Ontario), greenst.,
granites, etc. of, 47, 61, 63 w. chem.
anal.

Muscovite in Antrim Cretac. rocks,
570 et segg. & tables ii-iii.

Names of Fellows in arrear read out,
XCVill, xCix.

Nassau, vole. bombs in schalsteins of,
109-111 w. fig.

Natrolite in altered Cape Flora basalt,
489.

Neale, Cape (Franz Josef Land),
silicif. wood, etc. from, 506.

Nemeli (S. Arcot), micropegmatitic
augite-diorite of, 417 & pl. xxix.

Neolithic lake-series of Newbury,
430-482 fig.

Newbury (Berks), gravels & assoc.
deposits at, 420-437 figs. & pl. xxx
(map & sections).

Newron, E. T., & J. J. H. TeAu, on
Rocks & Foss. coll. by Jackson-
Harmsworth Exp. in Franz Josef
Land, 477-518 figs. w. map. & pls.
xxxvii-xli (microsc. sections &
foss. ).

Neza-i-Sultan (Baluchistan), a nat.
pillar of vole. agglom., 293, 294 fig.

Nickel-district of Sudbury, geol. &
petrogr. of, 40-66 w. map & chem.
anal.

Neggerathiopsis Hislopi, 322 & pl.
xxi. figs. 4 0, 6.

Norite of Murray Mines, 48; of Windy
Lake, 57.

North Down (Somerset), section to
Battin’s Farm, 439.

Northbrook I. (Franz Josef Land),
situat. of basalt on, 480.

Northbrook Street (Newbury), vert.
section, 431.

Northern Division, COretac. of Co.
Antrim, 545, 567-568.

Notgrove Freestone of Cleeve Hill,
612.

Nubian Desert, geol. of portion S.E.
of Korosko, 360-376 & pl. xxvi
(eae): elu

Nubian Sandstone in Korosko dis-
trict, 360, 361, 362.

Q.J.G.8. No. 212.

GENERAL INDEX.

641

Nucula sp. (Chalk Rock), 378 & pl.
xxvil. figs. 1 & 2.

Nuculana cf. siliqua, 377.

Nummulitice of Cutch, laterites assoc.
with, 237. ,

Nyborg (Norway), 187, 139, 149.

Oakhampton (Somerset), Morte Slates
of, 439, 442; foss. fr. same, 445 e¢
segg. & pls. xxxlii-xxxiv.

Oberscheld (Nassau), vole. bombs of,
109-111 w. fig.

Obolella cf. nitens, 67.

Officers elected, xxii.

Old Red Sandstone age of red rocks
of Bunmahon, 270 e¢ segg.; con-
glom. of Portraine, 521.

Oligoclase, microliths in Baluchistan
lava, 800 & pl. xx; twinned erystals
in Bharab Chah basalt, 301; in
quartz-syenite fr. Sarlat range, 304.

Olivine in Baluchistan andesites, 298,
299 & pl. xix; in Franz Josef
Land basalts, 484.

Olivine-diabase dykes of Sudbury
district, 62 w. chem. anal.

Onaping (Ontario), gneiss near, 42;
hornblende-porphyry near, 57.

‘Oolite (Inferior),’ success. in Cottes-
wold Hills, 615-617.

Oolitic plant-remains in Franz Josef
Land, 505, 513.

‘ Ophiolite’ in Ballydouane Bay, 274.

Orbiculoidea sp. (Keisley Limest.), 67.

Ordovician age of Keisley Limest.,
104; of red rocks of Bunmahon
denied, 270 ez segq.

Orthis Actonia, 68.

alternata (?), 70.

— cf. argentea, 69.

biforata, 68.

— biloba, 68.

— calligramma, 68.

cf. conferta, 69.

elegantula (?), 70.

flabellulum (?), '70.

keisleyensis, sp. nov., 69 & pl. vi.

vespertilio, 69.

Orthoceras cf. elongatocinctum, 77.

cf. scabridum, 77.

Ostracoda of Keisley Limest., 67, 90.

Osirea carinata, zone of, see Yellow
Sandstone.

semiplana (?), 381.

Overlap and denudation in Cleeve
Hill district, 623.

Owny, F., presents his grandfather’s
portrait, iv.

Oxfordian, evid. of, at Cape Flora &
Windy Gully, 499, 501, 512.

2

642

Pal@odiscus, struct. of, 129 w. figs.;
affinities of, 130.

Paleolithic river-gravels of Newbury,
425-429 figs.

Paleozoic glacial beds of Varanger
Fiord, 137-146 w. map & pls. vili-
x, 1538-156.

Palagonia (Sicily) palagonite comp.
w. Franz Josef Land do. 485
chem. anal., 486.

Palagonite in Franz Josef Land
basalts, 485 et segg. w. chem. anal.
aramoudras at Soldierstown, 545.

Pare-y-Meirch (Flint), drift near,
344.

Parker, T., exhibits
sapphires, ete., il.
Parkinson, J., on Igneous Rocks in
N. Pembroke, 465-476 w. fig. &

pl. xxxvi (microse. sections).

Patcham (Cutch), boulder-beds in N.
of, 233.

‘Pavement ’-structure, 54.

Peat w. human relics nr. Newbury,
430.

Pebble-conglomerate (Cretac.) of Co.
Antrim, chem. & micromineral.
comp. of, 579.

Pebidian, quartz-porphyry dykes in,
lxxiv; Peb. rocks in Caernarvon,
Ixxv; of Anglesey, 350.

Pecten cf. demissus, 498.

Pedina, ambulacr. plates of, 118 fig.

Pedinothuria, gen. nov., 119.

cidaroides, sp. nov., 119 & pl. vii.

Pelanechinus, arabulacr. plates of, 116
figs.

Panne philarchus comp. w. Plio-
saurus ferox, 177.

Pembroke earthquakes of Aug. 1892
& Nov. 1893, 157-176 w. map &
pl. xi.

‘ Pembrokeshire, pre-Cambr. of, 1xxi ;
(North), igneous rocks of, 465-476
w. fig. & pl. xxxvi (microse. sections).

Peninsular Division, Cretac. of Co.
Antrim, 543, 565-567.

Perceval, 8. G., exhibits arborescent
Carb. Limest., xcvi.

Permo-Carboniferous age of 8. African
coal-bearing strata, 335.

Perofskite in Rauenthal rocks, 252.

Perumbakam (S. Arcot), chem. anal.
of augite-andesite from, 409; mi-
crosc. section of same, pl. xxix.
fig. 3.

Petalograptus defined, 188 ; phylogeny
of, 210.

folium, 188 & pl. xiii. figs. 1-5.

minor, sp. nov., 201 & pl. xiv.

figs. 17-21.

Queensland

GENERAL INDEX.

[Dec. 1897,

Petalograptus ovatus, 199 & pl. xiv.
figs. 15-16.

palmeus, 193 & pl. xiv. figs. 1-4;
var. latus, 195 & pl. xiv. figs. 5-8 ;
var. ovato-elongatus, 197 & pl. xiv.
figs. 11-14; var. tenuis, 196 &
pl. xiv. figs. 9-10.

Petraia sp. (Morte Slates), 456 &
pl. xxxiii. figs. 6-7.

Phormosoma bursariwm,
plates of, 116 fig.

luculentum, do., 117 fig.

Uranus, do., 115 fig.

Phosphatic nodules fr. Franz Josef
Land, 499 & pl. xxxvii. fig. 6.

Phyllites, Huronian, nr. Sudbury, 45:
(?) fr. Wadi Om Nabadi, 370.

Phyllotheca | Equisetites| cf. columnaris,
504 & pl. xli. figs. 1-3.

sp. (Permo-Carb.), 324 & pl. xxiv.

1

ambulacr.

fig. 1.

Pickwell Down Sandstones, 440, 442
& pl. xxxv (map).

Pile : dwelling found at Newbury,
432.

Pinus sp. (Franz Josef Land), 494 &
pl. xxxvill. figs. 6-8.

Pisidium miliwum in Newbury shell-—
marl, 436.

Plagioclase, combined twinning in
Sudbury rocks, 62.

Plagioclase-crystals
augite-diorites, 407.

Planer Kalk fauna comp. w. that of
Chalk Rock, 395.

Planorbis glaber in Newbury shell-
marl, 436.

Plants, Pleistoc., fr. Casewick, Shackle-
well, & Grays, 463-464; Jurass.,
etc. fr. Franz Josef Land, 494 &
pl. xxxvili, 503-504 & pl. xli, 506
et seqq.

Platyceras cf. cornutum, 79.

verisimile, sp. nov., 79 & pl. vi.

Plectambonites quinquecostata, 70.

Schmidti, 70.

transversalis (?), 70.

Pleistocene plants fr. Casewick,
Shacklewell, & Grays, 463-464.

Pleurotomaria notabilis (?), 80.

Plicatula Barroisi, 388 & pl. xxvii.
figs. 18 & 19.

Pliosaurus ferox, struct. of skull of,
177-185 figs. & pl. xii.

Plocoscyphia (?)-meshes in Jnoceramus-
Crispi zone, 576. ;

Podozamites lanceolatus (7), 495 &
pl. xxxviii. fig. 12.

Polyzoa of Keisley Limest., 77, 92.

Poolatunish Point (Waterford), igne-
ous & other rocks of, 276, 278.

in §. Indian

Vol. 53.|

Porphyrite (?), crushed, fr. Wadi Om
Nabadi, 369.

Porphyritic diabase fr. Nubian De-
sert, 367.

Porth Gwyfen (Anglesey), section
descr., 354.

Portland, I. of, Cycadeoidea gigantea
from, 22-38 figs. & pls. i-v.

Portraine Inlier (Co. Dublin), 520-
539 figs. & pls. xlii-xliii (section
& map).

Post-Nummulitic age of Cutch late-
rites, 237.

PostLETHwaire, J., exhibits vole. bomb,

v.

Pothole w. rounded boulders, in Wadi
Om Risha, 363 fig.

Prasopora Graye, 84.

Pre-Cambrian, geol. & biol. history of,
lxv-xcii ; rocks of Anglesey, 349.
Pre-Cretaceous (?) conglom. in Nubian

Desert S.E. of Korosko, 362.
Pre-Glacial drift of Newbury, 420.
Prescelly Hills (Pembroke), igneous

rocks of, 465-476 & pl. xxxvi (mi- _

crose. sections).

Pressure-effects shown in rocks fr.
Nubian Desert, 372.

Prestwicu, J., obituary of, xlix.

Prestwicu bequests, i.

Priest's Chamber (Portraine), 530;
thrust-conglom. at, 532 fig.; diagr.
of cliff at, 533.

‘Primary injection,’ gneiss of, in
Anglesey, 353, 354 fig.

Primitia M‘Coyi, 67, 537.

Pseudo-breccia assoc. w. Rauenthal
serpentine, 260.

Piilodictya costellata, 77.

recta, 77.

Pumice fr. Baluchistan, 302.

Purbeck Beds of Portland, Cycadeoi-
dea gigantea from, 22-38 figs. & pls.
i-y.

Purley Boulder exhibited, xciii ;
comp. w. Betchworth boulders, 213,
217, 220.

Madras

‘Pyroxene-granulites’ of
Presidency, 405, 406.

Pyroxenic minerals, altered, in rocks

fr. Nubian Desert, 371.
Pyrrhotite, nickeliferous, of Sudbury
district, 40, 51, 52.

GENERAL INDEX.

643

ee nee

Quartz-conglomerates (O. R. 8.) in
Ballydouane Bay, 274, 275; of
Kennedy’s I. & Knockmahon, 281.

Quartz-diorite fr. Nubian Desert, 367.

Quartz-syenite fr. Baluchistan, 3803 &
pl. xx (microsce. sections).

Quartzites, Huronian, nr. Sudbury,
43.

‘ Quartzite-reefs’ of Cutch, 243.

Radiolarian chert fr. Franz Josef
Land, 511.

Rafinesquina deltoidea, 71.

(?) var. undata, 71.

expansa, 70.

Rainfall in Baluchistan, 293; in
Nubian Desert, 363, 376 ; formerly
greater (?) in Cotteswold area, 626.

Raised beaches of Varanger Fiord,
147-151; in Franz Josef Land,
508.

Raisin, C. A., Nat. & Orig. of Rauen-
thal Serpentine, 246-268 fig. & pls.
xvi-xvii (map & microsc. sections) ;
Petrol. of Nubian Desert S.E. of
Korosko, 364-373.

Ran of Cutch, 239 et seqq.

Rauenthal (Vosges), nat. & orig. of
serpentine of, 246-268 fig. & pls.
Xvi-xvii (map & microse. sections).

Rayside Station (Ontario), altered
rocks nr., 53.

Reape, T. MeLvard, on Glacio-marine
Drift of Vale of Clwyd, 341-347
w. section & pl. xxv (map).

Reading Beds ur. Newbury, 422.

Red Rocks nr, Bunmahon, 269-288
figs.

a F. R. C., Fauna of Keisley
Limest., 67-105 & pl. vi; Red
Rocks nr. Bunmahon on Coast of
Oo. Waterford, 269-286 figs.; on
Foss. fr. Portraine Inlier, 535-538.

Regenerated granites, 44.

Registan sand-desert, 290.

Rerp, CLEMENT, Bigsby Medal awarded
to, xlvii; on Pleistoc. Plants fr.
Casewick, Shacklewell, & Grays,
463-464.

Reussianum-zone, see Chalk Rock.

Reynoups, 8. H., & Garpiner, C. L.,
an Account of the Portraine Inlier
(Co. Dublin), 520-535 figs. & pls.
xlii—xliii (section & map).

Rheetic Beds at Colin Glen, 548-549.

644

Rhiptozamites (?) ef. Gepperti, 504 &
pl. xli. figs. 1-7.

Rhynchonella, distrib. of, in Antrim
Cretac., 605.

Rhynchonella hercynica (?), 451 & pl.
xxxiv. figs. 4 & 5.

nympha (?), 451 & pl. xxxiv.
figs. 6 & 7.

Rhynchotrema cf. dentatum, 73.

Ricuarps, H. P., on Gravels & Assoc.
Deposits at Newbury, 420-436 figs.
& pl. xxx (map & sections).

Richthofen, Cape (Franz Josef Land),
plant-remains, etc. from,
514.

River-gravels of Newbury, 425-429
fies,

Rosggrtson, D., obituary of, lxiv.

Rod Huish (Somerset), Devon. Limest.
foss. from, 441.

Rolling Bank (Cleeve Hill), diagr. of
quarries BE. of, 614; section to
Hewlett’s Hill, 616; diagr. sketch
showg. fissure-fault, 619.

Rosebush (Pembroke), 465; ancient
lavas of, 474.

Ross, G. E. A., presents portraits of
var. geologists, li.

Rutile in Rauenthal rocks, 253; in
Antrim Cretac. rocks, 570 e¢ seqq.
& tables ii-ii1; enclosures in horn-
blende-diabases, 366.

Saindak Mts. (Baluchistan), list of
ores & rocks, 305.

Satter, A. E., exhibits flint-imple-
ments, xCvi.

Sand-dunes in Baluchistan -desert,
290 fig., 291.

Sanosra (Cutch), infratrappean grits
of, 235, 236.

Saussurite flaser-gabbro of Travers
Mine, 59.

Schalsteins of Nassau, vole. bombs in,
109-111 w. fig.

Schists, ‘simple,’ of Anglesey, 351;
erystall.,in Nubian Desert S.E. of
Korosko, 361.

Scotland, pre-Cambr. rocks of, Ixxxiy.

Sea-waves assoc. -w. Pembroke earth-
quakes, 165, 173.

‘Secondary injection,’ gneiss of, in
Anglesey, 355, 356 fig.

Secondary minerals in §S. Indian
augite-diorites, 408.

Senonian age of Antrim beds, 542,
544.

Serpentine of Rauenthal, nat. & orig.
of, 246-268 fig. & pls. xvi-xvii
(map & microse, sections).

GENERAL INDEX.

OUT, ”.

[Dec. 1897,

Seven Pagodas (Chingelput), chem.
anal. of pyroxene from, 407; do. of
augite-diorite from, 409; microsce.
sections of same rock, pl. xxix. figs.
1&6.

Seven Wells (Gloucester), 625.

Sevenhampton Valley (Gloucester),
orig. of, 626, 627.

Srwarp, A. C., on Cycadeoidea gigan-
tea, sp. nov., fr. Purbeck Beds of
Portland, 22-38 figs. & pls. i-v;
on Assoc. of Sigillaria & Glosso-
pteris in 8. Africa, 315-338 figs. &
pls. xxi-xxiv.

Shacklewell (Middlesex),
plants from, 463.

Suarp, W., obituary of, lx.

Sigillaria assoc. w. Glossopteris in
S. Africa, 315-340 figs. & pls. xxi-
XXiv.

Brardi, 326 & pls. xxii—xxiii,
327 figs., 829 figs.

—— ? sp. (Permo-Carb.), 330 &
pl. xxii. fig. 4 & pl. xxiv. fig. 3.

Silicification of Cretac. sponges, ete.,
602-604; interprismatic, of Znoce-
ramus-tests, 556, 581, 583.

Silicified wood in Franz Josef Land,
508-510 & pl. xli. fig. 11.

Silurian strata in Morte Slate Series,
443.

‘Simple Schists’ of Anglesey, 351.

Skye (Hebrides), Inf. Ool. ammonites
fre, 11;

Suack, H. J., obituary of, xi.

Slieve Gallion (Derry), Cretac. of, 566.

Snelsmore Common (Berks), section
deser., 421.

Snider township (Ontario), igneous
rocks of, 55.

Snowshill Clay of Cleeve Hill, 611,
624.

Soldierstown (Antrim), paramoudras
at, 545.

Somerset (West), Morte Slates, &
assoc. beds in, 438-462 figs. & pls.
Xxxi-xxxv (map & foss.).

Sound in earthquakes, nat. of, 163,

~ 167.

Sound-area of Pembroke earthquakes,
170.

Southern Division, Cretac. of Co.
Antrim, 548, 545-547.

Southern Drift around Newbury, 420;
comp. w. Donnington Gravel, 424.

Special General Meetings, iv, vii.

Species, foss., reappearing in higher
zones, 605.

Spheronites pyriformis, 82.

Sphene in quartz-syenite fr. Sarlat
range, 304,

Pleistoc.

Vol. 53.]

Sphenopteris sp. (Permo-Carb.), 324
fig., 332.

Spherulitic rocks in. N. Pembroke,
467 et segq. & pl. xxxvi.

Spirifera spp. (Morte Slates), 450 &
pls. xxxi. fig. 10, xxxiv. fig. 3.

Spitsbergen rocks comp, w. Franz
Josef Land do., 491.

Spondylus latus, 387.

spinosus, 385.

Sponges, conn. w. flint, 603: spicules
fr. Morte Slates, 456; in Franz
Josef Land chert, 507.

Spongiarian Zone, see Chloritic Chalk
& Belemnitella vera-zone.

Squires Hill (Antrim), Cretac. of,
552.

St. Asaph Drift, 347.

St. David’s (Pembroke), vole. orig. of
pre-Cambr. at, lxix.

St. Kenny’s Well (Portraine), 526,
530, 531 e¢ seqq.

Starkenbach (Vosges) serpentine comp.
w. Rauenthal rock, 261.

Statistics of Society, xviii.

Sreppinc, P. W. D., on Granite-
boulders fr. Betehworth Chalk, 213-
219 figs. & pl. xv.

Stenopora fibrosa, 84.

Stephen, Cape (Franz Josef Land),
plant-remains found at, 503-506 &
pl. xli; vert. section betw. Cape
Grant and, facg. 512.

Stobie Mine (Ontario), rocks of, 44,
59.

SrrauAn, A., on Glacial Phenom. of
Palzoz. age in Varanger Fiord, 137-

146 w. map & pls. viii-x; Raised:

Beaches & Glac. Deposits of Var-
anger Fiord, 147-153.

Streptelasma europeumn, 83.

Streptis monilifera, 71.

‘ Streptorhynchus (?) persarmentosus,
454 & pl. xxxil. figs. 4-5.

Striz, glacial, along shores of Var-
anger Fiord, 152.

Striated sandstone at Bigganjargga,
141 & pl. x.

Stropheodonta teniolata, 452 & pl.
xxxiv. figs. 8 & 9.

Strophomena antiquata, 70.

corrugatella, 70.

—— [Stropheodonta| explanata(?),
452 & pls. xxxi. figs. 11-13, xxxil.
figs. 1-3.

Submergence, periods of, in Brit.
Cretac., 600.

‘ Subrecent. concrete’ of QCutch, 223.

Sudbury (Canada) nickel district, geol.
& i da of, 40-66 w. map & chem,
anal,

GENERAL INDEX,

645

Superficial deposits of Cutch, 223-244
w. map & sections.

Syntrophia affinis, sp. nov., 73 &
pl. vi.

Table Mountain Sandstone rocks nr.
Johannesburg, 312. :

Tamlaght (Derry), Cretac. of, 566.

Tarr, R.8., on Changes of Level in
Bermuda Is., 222 [ads.].

Treat, J.J. H., & H. T. Newton, on
Rocks & Foss. coll. by Jackson-
Harmsworth Exp. in Franz Josef
Land, 477-518 figs. w. map &
pls. xxxvii—xli (microse. sections &
foss.).

Temperature, wide range of, in Ba-
luchistan, 294.

Terebratula, distrib. of, in Antrim
Cretac., 605.

Buckmani-grit of Cleeve Hill,
612.

—— Phillipsiana-beds of Cleeve Hill,
613-615. -

Terrace-gravel of Newbury, 425-427
figs.

Tertiary strata(?) in Franz Josef
Land, 514.

Thick-shelled gasteropoda, numerous
in Chalk Rock, 399.

Thrust-conglomerates of Portraine
inlier, 524, 530, 531 e¢ seqgq., figs.

Thyrsopteris sp. (Franz Josef Land),
495 & pl. xxxviil. figs. 13-14.

Tilat Abda Wells (Nubia), rocks fr.
near, 362, 365, 367 ; chem. anal. of
water of, 374, 375.

‘ Till, special uses of term, 142, 150.

Tircreven Burn (Antrim), Cretac. of,
567.

Titaniferous magnetite of Murray
Mines, 52.

Topaz (?) in White Limest.of Antrim,
582

Torridonian (?) age of Gaisa Beds,
143.

Tourmaline (?) in altered gabbro, 365;
in Antrim Cretac. rocks, 571 &

Trapezium rectangulare, sp. nov., 392
& pl. xxviii. figs. 11-12.

trapezoidale, 391 & pl. xxviii.
figs. 9-10.

Travers Mine (Ontario) eruptive, 59.

Treborough (Somerset), section to
Withycombe, 439; Morte Slates,
etc. in district, 440; foss. fr. same,
447 e¢ seqg. & pls. xxxi-xxxiii.

Triarthrus, models of, exhibited, xevi.

Trias (?) of South Africa, Sigillaria,
Glossopteris, ete. from, 310-314 w.

646

map & sections; junct. w. Cretac. in
Murlough Bay, 565 & pl. xliv. See
also Keuper.

Trigonia-grit, Lr., of Cleeve Hill, 612;
Upper, in Cotteswold area, 622 &
pl. xlvi (map).

Trilobita of Keisley Limest., gen. con-

sid., 88; fr. Portraine inlier, 524, -

029, 5385-587, 588.

‘'Trilobite-shales’ of Portraine inlier,
524.

Trinucleus seticornis yar. portrainen-
sis nov., 538.

Triplesia insularis, 71.

Troms6 (Norway), shell-marl, ete. at,
150

Tuffs (?) fr. Franz Josef Land, 499.

Turonian age of Antrim beds, 542,
544, 564, 591, 592.

Tween Rocks (Franz Josef Land),
505.

Uriconian, pre-Cambr. age of, lxxxiii.

Vads6 (Norway), 137, 1389; aneroid-
measurem. taken near, 147; glacial
deposits near, 151.

Varanger Fiord (Norway), Palzoz. gla-
cial phenom. in, 137-146 w. map &
pls. vili-x, 153-156; raised beaches
& glacial deposits of, 147-153.

Veins, contemporaneous, repres. by
micropegmatite, 414, 416, 419.

Vein-quartz fr. Abu Sinaiyat, 370,
372.

Vereeniging (Transvaal), sections at &
near, 312, 313.

Vertebraria fr. Casey’s Township, 322.

Volcanic breccia nr. Sudbury, 45 w.
chem. anal.; bombs in schalsteins
of Nassau, 109-111 w. fig.; vole.
rocks of pre-Cambr. era, lxxi et
segg.; of Baluchistan-Afghan fron-
tier, 289-309 figs. & pls. xvili-xx
(map & microse. sections).

Volcanoes of Central America, 221 ;
of Koh-i-Taftan, 292, 293.

Wadi Om Nabadi, ancient gold-work-
ings at, 361; igneous rocks from,
369 ; phyllites (?) from, 370.

Wadi Om Risha (Nubia), rounded
boulders in pothole, 363 fig.

Wahnapitae (Ontario), gneiss near,
49

Watxer, T. L., Geol. & Petrogr. of
Sudbury (Can.) Nickel-district, 40-
66 w. map & chem. anal.

Water fr. wells in Nubian Desert,
chem. anal. of, 374, 375. ~

Water-retaining beds in N. Cottes-
wolds, 624.

GENERAL INDEX.

[Dec. 1897,
Water-supply in Nubian Desert,
363.

Waves (sea-), assoc. w. Pembroke
earthquakes, 165, 173.

Wells in Nubian Desert, 363.

Wuipporne, G. F., Descr. of Foss. fr. ~
Morte Slates, 445-458 & pls. xxxi-
XXXiv.

White Chalk of Co. Antrim, 550 e¢
segg. See also White Limestone.
White Limestone of Co. Antrim, 541,
545 et segg.; chem. & micromineral.
comp. of, 578, 580-582 & tables

White Mountain (Antrim), Cretac.
betw. Cave Hill and, 548-553.

White Park Bay (Antrim), Cretae.
betw. Downhill and, 568.

Whitefield (Somerset), Morte Slates
at, 443.

Whitehead (Antrim), Cretac. of, 557-
559.

Whitewell (Antrim), Cretac. of, 553.

Wuirtnety, J. D., obituary of, ly.

Whitson Lake (Ontario) eruptive, 47 ;
chem. anal. of same, 56

Whittington (Gloucester),
deser., 608.

Wind, action of, in Cutch, 227 e¢ segq.,
242, 243; in Baluchistan, 293; in
Nubian Desert, 372.

Windy Gully (Franz Josef Land),
foss. found at, 500 & pl. xl.

Windy Lake (Ontario) eruptive,
56

section

Witchellia-grit of Cleeve Hill, 613,

Withycombe (Somerset), section to
Treborough, 439.

Wiveliscombe (Somerset), Morte Slates
& assoc. beds in district, 442.

Wollaston Fund, list of recipients,
XXVi.

Wollaston Medallists, list of, xxv.

Wood, silicified, in Franz Josef Land,
508-510 & pl. xli. fig. 11.

Woodburn Glen (Antrim), Cretac. in,
554-557; chem. & micromineral,
comp. of rocks from, 569-573, 574-
pl. xlv.

Woops, H., on Chalk Rock Mollusca,
Pt. II, 377-403 & pls. xxvii-xxviii.

Woopwarp, B. B., on Mollusca fr.
Kennet Valley Deposits, 434-436.

Woopwarp, H. B., Murchison Medal
awarded to, xl.

Wootacort, D., Explan. of Claxheugh
section, Co. Durham [idle only],
xcix.

Worth, R. N., obituary of, 1x11.

Worthington Mine (Qntario), rocks
of, 44, 45, 60,63. 2°

4 Hh

Vol, 53. | GENERAL INDEX. 647

Wrekin (Shropshire), pre-Cambr. ‘Younger Granites’ of Sudbury dis-
rocks of, Ixxxi. trict, 61.

Y Graig (Anglesey), sections descr., Zamiopteris (?) cf. glossopteroides, 504
391, 353. & pl. xl. figs. 4-5.

Yellow Sandstones (Cretac.) of Co. Zircon in Antrim Cretac. rocks, 572
Antrim, 542, 549 e¢ segg.; chem. & et seqg. & tables ii-iii.
micromineral. comp. of, 572-574; Zwart Koppies (Transvaal), Lepido-
seq. & correl. of, 589-591. dendron found at, 318, 314, 315.

END OF VOL. LIII

PRINTED BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET.

PROCEEDINGS

OF THE

GEOLOGICAL SOCIETY OF LONDON.

SESSION 1896-97.

November 4th, 1896.
Dr. Henry Hicks, F.R.S., President, in the Chair.

The Presrpent referred to the loss which the Society had sustained
by the decease of Prof. A. H. Gruzn, M.A., F.R.S., who had served
for some years on the Council, and was Vice-President at the time
of his death. His wide knowledge of science, his perfect upright-
ness of character, and his genial good-nature were greatly valued by
all those who had the privilege of coming into contact with him.

The Presipenr further announced that the Council had that
afternoon passed the following resolution :—

‘The Council of the Geological Society are deeply sensible of
the loss which they have sustained in the death of Prof. GrEEn,
M.A., F.R.S., one of their Members, and a Vice-President of
the Society. In placing on record their acknowledgment of
the services which he has often rendered to the Society, they
desire to express their heartfelt sympathy with Mrs. Green and
the family in their sudden bereavement.’

The Presrpent announced that Lady Prusrwicu, in fulfilment of
the terms of a bequest of her late husband, had offered to the Society
260 bound volumes of geological tracts from his Library. Also
that a sum of £800 had been bequeathed to the Society by
Sir Joseph Prestwich, the interest to be applied to the triennial
award of a medal and fund: this bequest to take effect subsequent
to the decease of Lady Prestwich.

VoL. LIII. at

li PROCEEDINGS OF THE GEOLOGICAL socreTy. [Feb. 1897,
The List of Donations to the Library was read.

The SkrcRETARY announced that the Rev. P. B. Bropirs, M.A.,
F.G.S., had presented to the Society a framed platinotype portrait
of himself; that Capt. G. E. A. Ross, F.G.S., had presented eight
lithographic portraits of distinguished geologists; and that Miss
Hawkins had presented a portrait of her late father, Waterhouse
Hawkins, Esq.

The following communications were read :—

1. ‘ Additional Note on the Sections near the Summit of the
Furka Pass (Switzerland).’ By T.G. Bonney, D.Sc., LL.D., F.R.S.,
V.P.G.8., Professor of Geology in University College, London.

2. * Geological and Petrographical Studies of the Sudbury Nickel
District (Canada).’ By T. L. Walker, Ph.D., M.A. (Communicated
by J. J. H. Teall, Esq., M.A., F.R.S., Sec.G.8.)

3. ‘On the Distribution in Space of the Accessory Shocks of the
Great Japanese Earthquake of 1891.’ By Charles Davison, Se.D.,
F.G.S.

The following specimens, etc., were exhibited :—

Rock-specimens and microscopic sections, exhibited by Prof.
T. G. Bonney, D.Sc., LL.D., F.R.S., V.P.G.S., in illustration of his
paper.

Photographs taken by C. E. Monckton, Esq., exhibited by Horace
W. Monckton, Esq., F.L.S., F.GS.

Working Maps ofthe Secondary Rocks of Cutch, scale: 1 inch=
1 mile, exhibited by the Rey. J. F. Blake, F.G.S.

Sapphires and other precious stones from Withersfield, Central
Queensland, exhibited by Prof. R. Tate, F.L.S., F.G.S., on behalf
of Thos. Parker, Esq., of Rockhampton.

November 18th, 1896.
Dr. Henry Hicks, F.R.S., President, in the Chair.
Robert Brown, Esq., Desheyhur, vid Barrakur, E.I.R., Bengal,

India ; and accias Stuart Spens Stewart, Esq., B.Sc., “Waeeaans
University ; Manchester, were elected Fellows of the Society.

Vol. 53.] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. ill

The List of Donations to the Library was read.

The following communications were read :—

1. ‘On Cycadeoidea gigantea, a new Cycadean Stem from the
Isle of Portland.’ By A. C. Seward, Esq., M.A., F.G.S., University
Lecturer in Botany, Cambridge.

2. ‘The Fauna of the Keisley Limestone.—Part II. Conclusion.’
By F. R. Cowper Reed, Esq., M.A., F.G.S.

The following specimens, etc., were exhibited :—

Lantern-slides, exhibited by A. C. Seward, Esq., M.A., F.G.S., in
illustration of his paper.

Specimens exhibited by F. R. Cowper Reed, Esq., M.A., F.GS.,
in illustration of his paper.

Ammonites cf. Stemensi, Inferior Oolite Series, Holm, Portree,
collected by H. B. Woodward, Esq., F.R.S., F.G.S., and exhibited
by the Director-General of H.M. Geological Survey.

Ammonites near to Humphriesianus, Inferior Oolite, Scorybeck,
Portree, exhibited on behalf of Mrs. Robertson, Portree, by H. B.
Woodward, Ksq., F.R.S., F.G.S.

Sheet 10 of the Geological Survey Index Map of England and
Wales, scale: 4 miles=1 inch, presented by the Director-General
of H.M. Geological Survey.

December 2nd, 1896.
Dr. Henry Hioxs, F.R.S., President, in the Chair.

Edgar C. Agabeg, Esq., Gourangdi, Seetarampore, P.O., E.L.RB.,
Bengal; Jonathan Barnes, Esq., 1 Trafalgar Street, Broughton,
Manchester; Thomas Barron, Esq., Geological Survey Office, Cairo,
Egypt; Hugh John Llewellyn Beadnell, Esq., Geological Survey
Office, Cairo, Egypt; Lawrence Birks, Esq.,20 Dublin Street, Edin-
burgh; Reginald Marr Brydone, Esq., 152 Cambridge Street, S.W. ;
Peter Francis Daniel, Esq., Greymouth, New Zealand; Albert Hubert
Halder, Esq., 6 Drapers’ Gardens, E.C., and Bulawayo, Rhodesia ;
Henry Arthur Hinton, Esq., 42 Brownswood Road, Green Lanes,
N.; William Firth Holroyd, Esq., River Cottage, Lower Broughton ;
William MacLean Homan, Esq., Christiania ; Burton Samuel J ames,
Esq.,3 Douglas Villas, Streatham Common, 8.W. ; Henry Kay, Esq.,
Allen Road, Wolverhampton; E. Seaborn Marks, Esq., Astwood

IV PROCEEDINGS OF THE GEOLOGICAL society. [Feb. 1897,

House, 111 Cromwell Road, South Kensington, 8.W.; Gerald
N. Marks, Hisq., Astwood House, 111 Cromwell Road, South
Kensington, S.W.; William O’Connor, Esq., Church Villa, Pentre,
Glamorganshire; Thomas Parker, Esq., Tynedale, Rockhampton,
Queensland ; Edward Wyndham Penruddocke, Esq., 87 South Street,
Eastbourne; Alfred Edward Salter, Esq., 14 Amersham Road,
New Cross, S.E.; Major William Slade Vincent, 10 Bury Street,
St. James’s, 8.W.; and Cecil Frederic Webb, Esq., 2 Brougham
Terrace, West Derby Road, Liverpool, were elected Fellows of the
Society.

The List of Donations to the Library was read.

The Szecrerary announced that Frank Owen, Esq., F.G.S., had
presented to the Society a photographic portrait of his late grand-
father, Sir Richard Owen.

The following communications were read :—

1. ‘ Another possible Cause of the Glacial Epoch.’ By Prof.
Edward Hull, M.A., LL.D., F.R.S., F.G.S,

2. ‘On the Affinities of the Echinothuride, and on Pedinothuria
and Helikodiadema, two New Subgenera of Echinoidea.’ By
J. W. Gregory, D.Sce., F.G.S.

3. ‘On LEchinocystis and Paleodiscus, two Silurian Genera of
Kchinoidea.’ By J. W. Gregory, D.Sc., F.G.S.

A Special General Meeting was held at 7.45 p.m., before the
Ordinary Meeting, at which W. Warraxer, Esq., B.A., F.R.S., was
elected a Member of Council, and Sir ArcurpaLp Gerxre, D.Sc.,
D.C.L., F.R.S., a Vice-President of the Society, in place of Prof.
A. H. Green, deceased.

December 16th, 1896.
Dr. Hunry Hicks, F.R.S., President, in the Chair.

William Alfred Brend, Esq., B.A., 6 Argyll Road, Kensington, W. ;
Robert Hawthorn Kitson, Esq. B.A., Elmet Hall, Roundhay,
Leeds ; James Christian. Hisentwith Lawson, Esq., Finchley Lodge,
North Finchley, London, N.; Howard Nasmith Perrin, Esq., B.A.,
King’s College, Cambridge; and John Roberts, Esq., 28 Fisher
Street, Swansea, were elected Fellows of the Society.

Vol: 53:] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. Vv
The List of Donations to the Library was read.

The following communications were read :—

1. ‘On the Subdivisions of the Carboniferous Series in Great
Britain, and the True Position of the Beds mapped as the Yoredale
Series.’ By Dr. Wheelton Hind, F.R.C.S., F.G.S.

2. ‘Note on Volcanic Bombs in the Schalsteins of Nassau.’ By
Prof. E. Kayser, Ph.D., For.Corr.G.S. (Communicated by the
Secretary.)

The following specimens, etc. were exhibited :—

Fossils exhibited by Dr. Wheelton Hind, F.R.C.S., F.G.S., and by
Jonathan Barnes, Esq., F.G.8., in illustration of the paper by the
first-named.

Photographs of Quarries and specimens of Volcanic Bombs
im Schalsteins from Nassau, exhibited by Prof. E. Kayser, Ph.D.,
For.Corr.G.S., in illustration of his paper.

Volcanic Bomb from Falcon Crag, near Keswick, exhibited by
J. Postlethwaite, Esq., F.G.S.

Flint Implements (?) and Stones derived from the Boulder Clay
on the Coast at Runton, Norfolk, exhibited by W. J. Harrison, Esq.,
F.G.8.

Sheet 232, Abergavenny, Solid and Drift, of the 1-inch Map (New
Series) of the Geological Survey, by J. R. Dakyns, A. Strahan, and
W. Gibson, 1896; also Sheet 8 of the 4 miles-to-the-inch Index
Map, 1896, presented by the Director-General of that Survey.

January 6th, 1897.
Dr. Henry Hicks, F.R.S., President, in the Chair.

Barclay Bonthrone, Esq., Newton House, Newton of Falkland
Fifeshire ; Henry Arthur Pringle, Esq., Norseman, Western
Australia; Thomas Penrose Prout, Esq., Prospect Terrace, St.
Agnes, Cornwall ; and the Rev. J. Newton Vanstone, 12 Vancouver
Road, Catford S.E., were elected Fellows; M. E. Dupont, of
Brussels; Dr. Anton Fritsch, of Prague; Prof. A. de Lapparent, of
Paris; and Dr. Hans Reusch, of Christiania, were elected Foreign
Members ; and Prof. A. Hyatt, of Cambridge, Mass., a Foreign
Correspondent of the Society.

The following Fellows, nominated by the Council, were elected
Auditors of the Society’s Accounts for the preceding year :—Horacr
W. Moncxron, Esq., F.L.S., and Dr. J. W. Grecory.

vi PROCEEDINGS OF THE GEOLOGICAL society. [Feb. 1897.
The List of Donations to the Library was read.

The following communications were read :—

1. ‘On the Structure of the Skull of a Pliosaur.’ By C. W
Andrews, Esq., B.Sc., F.G.S.

2. ‘On the Pembroke Earthquakes of August 1892 and November
1893.’ By Charles Davison, Se.D., F.G.S.

3. ‘Changes of Level in the Bermuda Islands.’ By Prof. Ralph
S. Tarr. (Communicated by the Secretary.)

The following specimens, etc., were exhibited :—

An Ice-scratched (Neolithic) Celt, from Malton, Yorkshire, ex-
hibited by the Rev. R. Ashington Bullen, F.G.S.

Teeth of Pliosaurus from Ely and Potton, and of Plesiosaurus,
Ichthyosaurus, and Iqguanodon; Rib of a Saurian in Stonesfield Slate ;
Plocoscyphia and Ventriculites from Folkestone; part of Vertebra of
Elephas dredged from the Dogger Bank; and Vertebrate Remains
from Eastern Peru, exhibited by W. F. Gwinnell, Esq., F.G.S.

Sheets 2,4, and 5 of the Geological Survey Index Map of England
and Wales, presented by the Director-General of that Survey. .

Photographs taken in Bermuda, exhibited by Prof. Ralph S. Tarr,

in illustration of his paper.

January 20th, 1897.
Dr. Henry Hicxs, F.R.S., President, in the Chair.

Anthony Richard Cragg, Esq., Maristowe Cottage, Roborough,
South Devon; Edmund Alderson Sandford Faweett, Esq., 20 Thorn-
ton Hill, Wimbledon; and Joseph Lomas, Esq., 16 Mellor Road,
Birkenhead, were elected Fellows of the Society.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘On Glacial Phenomena of Paleozoic Age in the Varanger
Fiord.’ By Aubrey Strahan, Esq., M.A., F.G.S.

2. ‘The Raised Beaches and Glacial Deposits of the Varanger
Fiord.’ By Aubrey Strahan, Esq., M.A., F.G.S.

Specimens of glaciated rocks and raised-beach material, and
photographs were exhibited in illustration of the above-mentioned
papers by the author.

VoL. 53. | PROCEEDINGS OF THE GEOLOGICAL SOCIETY. vil

A Sprctat Gryerat Mertine was held at 7.45 p.u., before the
Ordinary Meeting, when the following Resolutions were proposed,
and unanimously adopted by the Fellows present :—

To repeal Section VIII., Article 3 of the Bye-Laws, and enact
as follows :—The Foreign Members shall be selected from the
list of Foreign Correspondents, or from among distinguished
Fellows who are not British subjects, and may be recommended
by Fellows in the same manner as already provided in the case of
Foreign Correspondents.

That Section XIII., Article 19 of the Bye-Laws be altered as
follows :—Whenever the balance in the hands of the Banker shall
exceed the sum requisite for the probable or current expenses of
the Society, the Council shall invest the excess in such securities
as are authorized for the investment of Trust Funds under the
Trustee Act, 1893, or any Acts amending or replacing the same.

February 3rd, 1897.
Dr. Henry Hicks, F.R.S., President, in the Chair.

Charles Vincent Bellamy, Esq., Roseau, Dominica, British West
Indies; James Bisset, Esq., B.A., 5 East India Avenue, Lendon,
E.C.; the Rev. Henry Blashell Foster, 46 Palace Street, Bucking-
ham Gate, S.W.; Josiah Rodda Hosken, Esq., Georgetown, British
Guiana; John Ellis Hughes, Esq., Ingfield House, Marston, near
Huddersfield ; and Harry W. Lake, Esq., 32 Shaftesbury Avenue, W.,
were elected Fellows of the Society.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘The Subgenera Petalograptus and Cephalograptus.’ By Miss
G. L. Elles. (Communicated by J. E. Marr, Esq., M.A., F.R.S.,
F.G.S.)

2. ‘On some Superficial Deposits in Cutch.’? By the Rey. J. F.
Blake, M.A., F.G.8.

The following specimens were exhibited :—

Specimens of Péetalograptus and Cephalograptus, exhibited by
J. EH. Marr, Ksq., M.A., F.R.S., F.G.S., in illustration of the paper
by Miss G. L. Elles.

Rock-specimens from Cutch and a photograph of Bhuj, Cutch,
exhibited by the Rey. J. F. Blake, M.A., F.G.S., in illustration of
his paper.

VOL. LIIL. | b

ANNUAL GENERAL MEETING,

February 19th, 1897.

Dr. Henry Hicks, F.R.S., President, in the Chair.

ReEPoRT OF THE Councit FoR 1896,

Ir is once more the pleasant duty of the Council to place on
record the uninterrupted financial prosperity of the Society, and
they have, in addition, to congratulate the Society on the fact that,
for the first time in a period of five years, there is an increase
in the number of Fellows. It had been pointed out already
that the decrease in numbers mentioned in previous reports was
proceeding at a diminishing ratio, and there appears good reason
to hope that the upward tendency now recorded will steadily
continue.

During 1896 the number of Fellows elected into the Society was
62, of whom 48 paid their Admission Fees before the end of the
year. Fees were also received during the past twelvemonth from
11 Fellows, who had been elected in 1895, the total accession of
new Fellows in 1896 being therefore 59.

On the other hand, there was a total loss of 47 Fellows during
the twelvemonth under review—26 by death, 18 by resignation,
and 3 removed from the List because of non-payment of their
Annual Contributions. It is satisfactory to note that the last-
named cause accounts for the removal of so very few names from
the List, as comapared with former years.

From the foregoing figures it will be seen that the actual
increase in the number of Fellows is 12 (as compared with
decreases of 1 in 1895, 11 in 1894, 46 in 1893, and 19 in
1892). | a

Of the 26 Fellows deceased 7 had compounded for their Annual
Contributions, 17 were Contributing Fellows, and 2 were Non-
Contributing Fellows.

On the other hand 8 Fellows during the past year became

Wol. 53: | ANNUAL REPORT. 1x

Compounders. The total accession of Contributing Fellows is thus
seen to be 51, and the total loss being 38 (18+17-+3), the increase
in the number of Contributing Fellows is 13.

Turning now to the Lists of Foreign Members and Foreign
Correspondents, the Fellows may recollect that at the end of 1895
there was 1 vacancy in the List of Foreign Members and 2 in the
List of Foreign Correspondents. In 1896 three Foreign Members
died. The vacancies thus left were in part filled by the election of
1 Foreign Member and 2 Foreign Correspondents, but at the end
of the year there were still 3 vacancies in the List of Foreign
Members and 1 in the List of Foreign Correspondents.

The Council need hardly remind the Fellows that they have, at
a recent Special General Meeting, sanctioned a modification of the
Bye-Laws such as will allow of the transfer of distinguished men
of science who are not British subjects, but have nevertheless
become Fellows, to the List of Foreign Members.

The total number of Fellows, Foreign Members, and Foreign
Correspondents, which on December 31st, 1895, was 1318, had
increased by the end of 1896 to 1329.

Proceeding now to the consideration of the Society’s annual
Income and Expenditure, the figures for 1896 may be summarized
as follows :—

The total Receipts, including the balance of £851 15s. dd.
brought forward from last year, amounted to £3728 Os. dd., being
£465 12s. 5d. more than the estimated Income for that year. On
the other hand, the total Expenditure during 1896 amounted to
£2959 17s. 5d., being less by £302 10s. Td. than the estimated
Jixpenditure for that year.

The actual excess of Expenditure over current Receipts in 1896
was £83 12s. 5d., but the following statement, as well as a glance
at the Balance Sheet, will show that this excess is entirely due to
Expenditure of a non-recurring character.

At the end of 1895 a Balance of £851 15s. 5d. was available for
extraordinary Expenditure. During 1896 the sum of £218 1ds. 3d.
was expended on the Electric Lighting Installation in the principal
Apartments of the Society, £63 7s. 6d. was paid for an Electric
Lantern and fittings, £89 3s. 10d. was the cost of the Redecoration
of the Basement, and £156 15s. was paid to the printers for work
in connexion with Part I. of the General Index to the first Fifty
Volumes of the Quarterly Journal. These items of non-recurring
Expenditure account for a total of £528 1s. 7d. Nevertheless,
there still remained at the end of 1896 a Balance of £768 3s. Od.
available for extraordinary expenditure.

The Council have pleasure in announcing the completion of
Vol. LII. of the Society’s Quarterly Journal and the commencement
of Vol. LITI. In bulk and in number of illustrations Vol. LIi:
conspicuously exceeded the average volume of the Quarterly Journal
during many years past.

The Fellows have now in their hands, in addition to the February
number of the Journal, the Record of Geological Literature added

x PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1897,

to the Society’s Library during 1896, and Part I. (A—La) of the ©
General Index to the first Fifty Volumes of the Quarterly Journal.
Every effort will be made to hasten the publication of the second
Part of the Index: the Fellows are doubtless fully aware of the
fact that, in no less degree than the work of compilation, the work
of seeing the Index through the press is both arduous and intricate,
but the Council are hopeful that the general utility of the Index
will be found proportionate to the labour and time bestowed upon
its preparation.

The want of some means by which deserving Fellows of the
Geological Society, whose circumstances have from some cause
become reduced, could be aided in paying their Annual Contri-
butions had long been felt. The Council have therefore decided
to institute, by means of voluntary subscriptions from the Fellows,
a Capital Fund, to be called the Geological Relief Fund, of which
the Council will be Trustees. It is proposed that the interest
accruing from this Fund should from time to time be applied by
the Council in aid of deserving Fellows. The response to the appeal
for subscriptions has not, so far, been quite as general as the Council
had ventured to hope; but they trust that it is sufficient to mention
this fact, to induce those Fellows who have not yet subscribed, to
furnish the means of placing the Relief Fund on a sound and
secure basis.

The question of the desirability of transferring the Society’s
collections to the Trustees of the British Museum, was brought up
for consideration at a Special General Meeting on May 20th last,
and after a prolonged discussion the previous question was carried
by 35 Ayes to 12 Noes.

The following Awards of Medals and Funds have been made by
the Council :—

The Wollaston Medal is awarded to Mr. W. H. Hudleston, in
recognition of his valuable services in promoting Geological
Science. |

The Murchison Medal, with a sum of Ten Guineas, is awarded
to Mr. Horace B. Woodward, in recognition of the value of his
work among many departments of the science, and especially in
connexion with the Neozoic rocks.

The Lyell Medal, with a sum of Twenty-five Pounds, is awarded
to Dr. George J. Hinde, in recognition of the great value of his
work in Invertebrate Paleontology.

The Bigsby Medal is awarded to Mr. Clement Reid, in testimony
of high. appreciation of the value of his researches among the
newer rocks of Britain.

The Balance of the Proceeds of the Wollaston Fund is awarded
to Mr. F. A. Bather, for his researches in Invertebrate Paleontology,
and to assist him in further investigations.

The Balance of the Proceeds of the Murchison Fund is awarded
to Mr. §. 8. Buckman, in recognition of the value of his work
among the rocks and fossils of Mesozoic age, and to assist him in
further researches.

Vol. 5 3: | ANNUAL REPORT. x1

A moiety of the Balance of the Proceeds of the Lyell Fund is
awarded to Mr. W. J. Lewis Abbott in recognition of his labours
among the post-Tertiary deposits, and to aid him in further work.

The other moiety of the Balance of the Proceeds of the Lyell
Fund is awarded to Mr. J. Lomas, in recognition of his researches
among the post-Tertiary deposits, and the rocks of North-western
England, and to assist him in further investigations.

Report oF THE LIBRARY AND Museum Committers ror 1896.

Your Committee have again to announce that many additions of
value and importance have been made to the Library, and now, as
in the past, the Donations far exceed in amount the Purchases.

During 1896 the Library received, by Donation, 113 Volumes of
separately published works, 394 Pamphlets and detached Parts of
works, 166 Volumes and 206 detached Parts of serial publications
(Transactions, Memoirs, Proceedings, etc.), and 16 Volumes of
Newspapers. ‘The total of accessions to the Library by Donation is
thus seen to amount to 279 Volumes, 394 Pamphlets, and 206
detached Parts. In addition, 78 Sheets cf Maps have been pre-
sented by various Donors.

Attention may be directed to such gifts, among others, as the
second part of the International Geological Map of Europe, com-
prising five sheets ; the Austrian Survey Map of the Neighbourhood
of Vienna in six sheets; Everett’s Geological Map of Australia,
presented by the Victorian Department of Mines ; and the nearly
complete Index Map of the Geological Survey of England and
Wales.

Turning from Maps to Books, especially prominent are the 2nd
edition of Phillips’s ‘Ore Deposits’ rewritten and enlarged by
Prof. H. Louis; Prof. Judd’s ‘Student’s Lyell’; Inostranzev’s
‘ Across the Main Range of the Caucasus’; Rosenbusch’s ‘ Mikro-
skopische Physiographie,’ 3rd edition, vol. il. Part 2; Vol. XI. of
the Royal Society’s Catalogue of Scientific Papers (Pet—Zyb); an
interesting collection of 260 Volumes of Tracts presented by Lady
Prestwich, in fulfilment of the wishes of the late Sir Joseph
Prestwich ; and many other valuable donations.

The Rey. P. B. Brodie presented the Society with a large framed
photographic portrait of himself; a portrait in oils of the late
Prof. Huxley was presented by Sir John Evans; a large portrait in
sepia of Prof. Bonney was presented by a group of subscribers; a
photograph of the late Sir Richard Owen was presented by his
grandson, Mr. Frank Owen; asmall portrait of the late Waterhouse
Hawkins was given by his daughter, Miss Hawkins; and eight
lithographic portraits of distinguished geologists were presented by
Capt. G. E. A. Ross.

The Books, Maps, and Portraits enumerated above were the gift
of 205 Personal Donors, 90 Government Departments and other
Public Bodies, aud 177 Societies and Editors of Periodicals.

X1i PROCEEDINGS. OF THE GEOLOGICAL society. [May 1897,

The Purchases made on the recommendation of the Standing
Library Committee amounted to 56 Volumes and 15 Parts of
separately published works, 26 Volumes and 23 Parts of works
published serially, and 11 Sheets of Maps of the French Geological
Survey.

The total expenditure incurred in connexion with the Library
during the past. twelvemonth is as follows :—

£ -sotee
Books, Periodicals, etc. purchased ..... a» CS 16iee
Binding of Books and Mounting of Maps.... 75 0 1

The following Lists contain the Names of Government Depart-
ments, Public Bodies, Societies, Editors, and Personal Donors, from
whom Donaticns to the Library have been received during the past
year :—

I. GoveRNMENT DEPARTMENTS AND OTHER Puptic Bopres.

Alabama.—Geological Survey of Alabama. Montgomery.

American Museum of Natural History. New York.

Austria.—Kaiserlich-Konigliche Geologische Reichsanstalt. Vienna.

Kaiserlich-Kénigliches N aturhistorisches Hofmuseum. Vienna.

Baden.—Grossher zozliches Ministerium des Innern. Geologische Landesanstalt.
Heidelberg.

Bavaria.—KOoniglich Bayerisches Oberbergamt. Munich.

Belgium.—Musée Royal d’Histoire Naturelle. Brussels.

Buenos Aires. Museo Nacional.

California.—State Mining Bureau. San Francisco.

California University. Berkeley.

Cambridge (Mass.).—Museum of Comparative Zoology, at Harvard College.

Canada.—Geological and Natural History Survey. Ottawa.

Chicago.— Field’ Columbian Museum.

Costa Rica.—Museo Nacional. San José.

Europe-—Commission Géologique Internationale. Berlin.

Finland.—Finlands Geologiska Undersékning. Helsingfors.

France.—Dépét dela Marine. Paris.

Ministére des Travaux Publics. Paris.

——. Muséum d’Histoire Naturelle. Paris.

Service de la Carte Géologique. Paris.

Great Britain—Admiralty. London.

Army Medical Department. London.

British Museum (Natural History). London.

Geological Survey. London.

Home Office. London.

India Office. London.

Ordnance Survey. Southampton.

The Lords Commissioners of Her Majesty’s Treasury. London.

Greece.—Observatoire National. Athens.

Hesse.—Grossherzogliches Ministerium des Innern. Geologische Landesanstalt.
Darmstadt.

Holland—Departement van Kolonien. The Hague.

Houghton (Mich.).—Michigan Mining School.

Hungary.—Kénigliche Ungarische “Geologische Anstalt (Magyar Foldtani
Tarsulat). Budapest.

Ta

Vol 53:4 ANNUAL REPORT. Xili

Tllinois.—State Museum of Natural History. Springfield.
India.—Geological Survey. Calcutta.
Iowa.—Geological Survey. Des Moines.
Italy— Reale Comitato Geolégico d'Italia. Rome.
Japan.—Geological Survey. Tokio.
Kingston (Canada).—Queen’s College.
La Plata Museum. La Plata.
Lausanne University.
London.—City of London College.
——. University College.
Lund Museum. Denmark.
Mexico.—Comision Geoldégica de Mexico. Mexico.
Milwaukee Museum.
Minnesota.—Geological and Natural History Survey. Minneapolis.
Missouri.—Geological Survey of Missouri. Jefferson City.
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.
- New Zealand.—Department of Mines. Wellington.
Norway.—Norges Geologiska Undersékning. Christiania.
Nova Scotia.—Department of Mines. Halifax.
Owens College. Manchester.
Pennsylvania.—Geological Survey. Harrisburg.
Perak Government. ‘Taiping.
Pisa.—Royal University.
Portugal.—Commiss&o Geologica de Portugal. Lisbon.
Prussia.—Ko6nigliche Preussische Geologische Landesanstalt. Berlin.
Konigliches Ministerium fiir Handel und Gewerbe. Berlin.
Queensland.—Department of Mines. Brisbane.
Geological Survey. Brisbane.
Roumania.—Museum of Geology and Paleontology. Bucharest.
Russia.—Comité Géologique. St. Petersburg.
Section géologique du Cabinet de S.M. ’Empereur. St. Petersburg.
Saxony.—Geologische Landesuntersuchung des Kénigreichs Sachsen. Leipzig.
Konigliches 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.
Tokio.—Imperial University.
; , College of Science.
Tufts College, Massachusetts.
United States Department of the Interior. Washington.
United States Geological Survey. Washington.
United States National Museum. Washington.
United States Treasury (Mint) Department. Washington.
Upsala University.
Mineralogical and Geological Institute.
Victoria.—Department of Agriculture. Melbourne.
. Department of Mines. Melbourne.
Washington (D.C.).—Smithsonian Institution.
Western Australia.—Agent-General for, London.
—. Department of Mines. Perth.
—. Geological Survey. Perth.
Wisconsin University. Madison.

—————_

II. Socterres anp Epirors.

Adelaide.—Royal Society of South Australia.

Alnwick.—Berwickshire Naturalists’ Club.

Bahia.—Instituto Geographico e Historico.

Barnsley.—Midland Institute of Mining, Civil and Mechanical Engineers

x1V PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1897,

Bath Natural History and Antiquarian Field Club.

Belfast Natural History and Philosophical Society.

Belgrade.—Annales Géologiques de la Péninsule Balkanique.

Berlin.—Deutsche Geologische Gesellschaft.

Gesellschaft Naturforschender Freunde.

——. Konigliche Preussische Akademie der Wissenschaften.

Zeitschrift fiir Praktische Geologie.

Birmingham.—Mason College.

Bombay Branch of the Royal Asiatic Society.

Bordeaux.—Sociéte Linnéenne.

Boston (Mass.).—American Academy of Arts and Sciences.

Boston Society of Natural History.

Brussels.—Société Belge de Géologie, de Paléontologie et d’Hydrologie.

—. Société Malacologique de Belgique.

Budapest.—Féldtani Kézlony (Geological Magazine).

Buenos Aires.—Instituto Geografico Argentino.

—. Sociedad Cientifica Argentina.

Caen.—Société Linnéenne de Normandie.

Calcutta.—Indian Engineering.

—. Asiatic Society of Bengal.

Cape Town.—South African Philosophical Society.

Cardiff—South Wales Institute of Engineers.

Chelmsford.—Felsted School Scientific Society.

Chicago.—Journal of Geology.

Christiania.—Nyt Magazin for Naturvidenskaberne.

Videnskabernes Selskab.

Cincinnati Society of Natural History.

Colombo.—Ceylon Branch of the Royal Asiatic Society.

Copenhagen.—Kongelige Danske Videnskabernes Selskab.

Cordoba.—Academia Nacional de Ciencias.

Cracow.—Académie des Sciences (Akademja Umiejetosci).

Darmstadt.—Verein fiir Erdkunde.

Dorpat.—Naturforscher Gesellschaft bei der Universitat Jurjew.

Douglas.—Isle of Man Natural History and Antiquarian Society.

Dresden.—Naturwissenschaftliche Gesellschaft ‘ Isis.’

Verein fiir Erdkunde.

Dublin.—Royal Dublin Society.

Royal Irish Academy.

Edinburgh.—Geological Society.

'——., Royal Scottish Geographical Society. 2
—. Royal Society. ! |
Ekaterinburg.—Société Ouralienne d’Amateurs des Sciences Naturelles.
Frankfurt a. M.—Senckenbergische Naturforschende Gesellschaft.
Glasgow.—Mitchell Library.

Natural History Society.

Gloucester.—Cotteswold Naturalists’ Field-Club.

Gratz.—Naturwissenschaftlicher Verein fiir Steiermark,

Haarlem.—Société Hollandaise des Sciences.

Halifax.—Yorkshire Geological and Polytechnic Society.

ae ee Leopoldinisch-Carolinische Deutsche Akademie der Natur-

orscher.

Hamilton (Canada).—Hamilton Association.

Havre.—Société Géologique de Normandie.

Hermannstadt.—Siebenbtrgischer Verein fir Naturwissenschaften.

Hertford.—Hertfordshire Natural History Society.

J ohannesburg.—Geological Society of South Africa.

Lausanne.—Société Géologique Suisse.

. Société Vaudoise des Sciences Naturelles.

Leeds.—Philosophical Society.

Leicester Literary and Philosophical Society.

Leipzig.—Naturwissenschaftlicher Verein fiir Sachsen und Thiiringen.

Zeitschrift fir Krystallographie und Mineralogie.

—. Zeitschrift fir Naturwissenschaften.

Liége.—Société Géologique de Belgique.

Société Royale des Sciences.

Lille.—Société Géologique du Nord.

Lisbon.—Sociedade de Geographia.

Liverpool.—Geological Association.

ee a I EE ————— ee ee

Vol, 53.| ANNUAL REPORT.

Liverpool.—Literary and Philosophical Society.
London.—Academy,

Athenzum.

British Association for the Advancement of Science.
Chemical News.

Chemical Society.

Colliery Guardian.

East India Association.

Geological Magazine.

Geologists’ Association.

Institution of Civil Engineers.

Tron and Steel Institute.

Tron and Steel Trades’ Journal.
Knowledge.

Linnean Society.

Mineralogical Society.

Nature.

Palzontographical 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.

Sanitary Institute.

Society of Arts.

Society of Biblical Archeology.

Society of Public Analysts.

Victoria Institute.

. Zoological Society.

Madison (Wis.).—Wisconsin Academy of Sciences.
Manchester Geological Society.

Literary and Philosophical Society.
Melbourne.—Royal Society of Victoria.
Milan.—Reale Istituto Lombardo di Scienze e Lettere.
Societa Italiana di Scienze Natural.
Montreal.—Natural History Society.
Moscow.—Société Impériale des Naturalistes.
Munich.—Konigliche Bayerische Akademie der Wissenschaften.
Nancy.—Académie de Stanislas.

New Haven (Conn.).—American Journal of Science.
—. Connecticut Academy of Arts and Sciences.
New York.—Academy of Sciences.

——. American Institute of Mining Engineers.

PAP ECE CPPERIEMERE AAEM TEI

London, Edinburgh, and Dublin Philosophical Magazine.

xv

Newcastle-upon-Tyne.—North of England Institute of Mining and Mechanical

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.
Spelunca.
Penzance.—Royal Geological Society of Cornwall.
Philadelphia.—Academy of Natural Sciences.
American Philosophical Society.
Wagener Free Institute of Science.
Pisa.—Societaé Toscana di Scienze Naturali.

XV1

PROCEEDINGS OF THE GEOLOGICAL SOCIETY.

Plymouth.—Devonshire Association for the Advancement of Science.
Institution, and Devon and Cornwall Natural History Society.
Rochester (N.Y.).—Academy of Sciences.

Geological Society of America.

Riga.—Naturforscher Verein.

Rome.—Reale Accademia dei Lincei.

Societa Geologica Italiana.

Rugby School Natural History Society.

Salt Lake City —Utah University Quarterly.

Santiago.—Deutscher Wissenschaftlicher Verein.

Sociedad Nacional de Mineria.

Société Scientifique du Chili.

Scranton (Pa.).—Colliery Engineer.

St. John (N.B.).—Natural History Society.

St. Petersburg.—Académie Impériale des Sciences.

——. Russische Kaiserliche Mineralogische Gesellschaft.
Stockholm.—Geologiska Foérening.

Kongliga Svenska Vetenskaps Akademi.

Stonyhurst Magazine.

Stuttgart—Neues Jahrbuch fiir Mineralogie, Geologie und Palaontologie.

Verein fiir Vaterlandische Naturkunde in Wiirttemberg.
Sydney.—Australasian Association for the Advancement of Science.
——. Linnean Society of New South Wales.

Royal Society of New South Wales.
Topeka.—Transactions of the Kansas Academy of Science.
Toronto.—Canadian Institute.

Toulouse.—Société d’ Histoire Naturelle.

Truro.—Royal Institution of Cornwall.

Turin.—Reale Accademia delle Scienze.

Vienna.—Berg- und Hiittenmannisches Jahrbuch.

Kaiserliche Akademie der Wissenschaften.

—. Kaiserlich-kénigliche Zoologisch-botanische Gesellschaft.
Mineralogische und Petrographische Mittheilungen.
Warsaw.—Annuaire Géologique et Minéralogique de la Russie.
Wellington (N.Z.).—New Zealand Institute.
Wiesbaden.—Nassauischer Verein fiir Naturkunde.
York.—Natural History Journal.

——. Yorkshire Philosophical Society.

Ill. Pxrrsonat Donors.

[May 1897,

Agassiz, A.
Alfaro, A.
Ameghino, F.
Andersson, J. G.
Andrews, C. W.
Ashley, G. H.

Bangs, O.
Bauerman, H.

Bascom, Florence.

Bather, F. A.
Bayley, W.S.
Becker, G. F.
Béclard, F.
Beecher, C. E.
Beesley, Mrs.
Berghell, H.
Bittner, A.
Blake, W. P.
Bonney, T. G.
Brodie, P. B.
Brogger, W. C.
Brough, B. H.
Brown, C. B.
Brush, G. J.

Bukowski, G. von.

Capellini, G.
Carez, L.
Choffat, P.
Clark, W. B.
Clarke, J. M.
Claypole, E. W.
Clemenis, J. M.
Coghlan, T. A.
Collins, J. H.
Cooke, J. H.
Cope, E. D.
Crawford, J. J.
Crema, C

Dall, W. H.
Dames, W.
Davison, C.
Dawson, G. M.

Delgado, J. F. N.

Degrange, A.
Dewalque, G.
Dickson, E.
Diener, C.
Dolifus, G.
Donald, Jane.

Donat, F. M. von.

Draghicénu, M. M.

Draper, D.
Drayson, A. W.
Dunlop, A.
Dupare, L.

Evans, Sir J.
Eyermann, J.

Fairchild, H. L.
Fairley, W.
Felix, J.
Ferrier, W. F.
Floyer, M. E.
Forir, H.
Fornasini, C.
Foster, C. Le N.
Fowler, T. W.
Francis, W.

Garland, J.
Gaudry, A.
Gerrard, J. J.
Gilbert, G. K.
Gilpin, E., Jun.
Goodchild, J. G.

Vol. 53.]

Gosselet, J.

Gregorio, Marquis A. de.
Gresley, W.S.
Grossmann, K.

Groth, P.

Grundy, J.

Guppy, R. J. L.

Gurley, W. F. E.

Hall, J.

Hanks, H. G.
Harlé, E.
Hawkins, Miss.
Hellsing, G.
Henderson, J. McC.
Herlin, R.
Hicks, H.

EL, H.

Hinde, G. J.
Holland, T. H.
Howard, F. T.

_ Hull, E.
Hutchinson, H. N.

Inostranzev, A.

Jack, R. L.

James, B.S.
James, J. F.
Jentzsch, A.
Jones, T. R.
Judd, J. W.

Kayser, E.

Kennel, J.

Keyes, C. R.

Kilian, W.

Kirkby, J. W.
Kjellmark, K.
Kjerulf, T.

Konen, A. von.
Krishtafovich, N. A.

Lapparent, A. de.
Lindstrém, G.
Lindvall, C. A.
_Lobley, J. L.
Lohest, M.
Loriol, P. de.

ANNUAL REPORT.

Louis, H.
Lubbock, Sir J.
Lyman, B.S.

McAlpine, D.
Maitland, A. G.
Marcou, J.
Marsh, O. C.
Martel, E. A.
Martin, E. A.
Mason, F. H.
Matthews, W.
Meli, R.
Merrill, G. P.
Merritt, W. H.
Michel-Lévy, A.
Miller, C. C. H.
Miller, S. A.
Mojsisovics von Mojsvar,
E. von.
Monckton, H. W.
Moreno, F. P.
Muff, H

Newton, E. T.
Newton, R. B.

(Ehlert, D. P.
Omboni, G.
Owen, F.

Papavasilion, S. A.
Pasquier, L. du.
Penfield, S. L.
Petterd, W. F.
Pocta, P.

Pollen, G. C. H.
Preller, C. S. Du R.
Prestwich, Sir J.
Prestwich, Lady.
Purey-Cust, H. E.
Reade, T. M.

Reid, C.

Renault, B.
Reusch, H.
Richards, Sir G. H.
Rosenbusch, H.
Ross, G. E. A.
Roussel, J.

xvil
Rutley, F.

Saise, W.
Salter, A. E.
Scudder, S. H.
Sernander, R.
Seward, A. C.
Sharman, G.
Shaw, F. G.
Sheppard, T.
Sherborn, C. D.
Skiff, F. J. V.
Spencer, J. W.
Spiller, J.
Strahan, A.
Struben, F. P. T.

Taber, C. A. M.
Talmage, J. E.
Tate, R.

Tate, i:
Teisseyre, L. W.
Thomas, J. J.
Thompson, B.

-Tiessen, E.

Toula, F.
Trabucco, G.
Traquair, R. H.
Tucker, W. T.
Tuckwell, W.
Tyrrell, J. B.

Wadsworth, M. E.
Wardle, T.
Whidborne, G. F.
Whitaker, W.
White, C. A.
Whiteaves, J. F.
Williams, G. H.
Wilson, E.
Wiman, C.
Winwood, H. H.
Woodward, H.
Woodward, H. I.
Woodward, H. P.

Yale, CG.
Zeiller, R.

XVill PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1897,

CoMPARATIVE STATEMENT OF THE NUMBER OF THE SOCIETY AT THE
CLOSE OF THE YEARS 1895 anp 1896.

Dec. 31st, 1895. Dec. 31st, 1896.
Compounders 3. occ - soe ss SOM je ee 306
Contributing Fellows...... SOG4 | anes 880
Non-contributing Fellows... MS RUNS 67
1241 1253
Foreign Members ........ or a ert oP 37
Foreign Correspondents... . OOM) ies cae 39
1318 1329

Comparative Statement explanatory of the Alterations in the Number
of Fellows, Foreign Members, and Foreign Correspondents at the
close of the years 1895 and 1896.

Number of Compounders, Contributing and Non-

contributing Fellows, December 31st, 1895 .. Boel.
Add Fellows elected during former year and paid 11
MT GOO Scie oo win kt Pk ee ace eee
Add Fellows elected and paid in 1896 ........ 48
1300
Deduct Compounders deceased.....'........+.- t
Contributing Fellows deceased .......... ay
Non-contributing Fellows deceased .... . 2
Contributing Fellows resigned .......... 18
Contributing Fellows removed .......... 3
— 47
1253
Number of Foreign Members and Foreign 7
Correspondents, December 31st, 1895 .... } /
Deduct Foreign Members deceased ........ 3
Foreign Correspondent elected } 1
ForeiputMiember cca eee
— 4
73
Add Foreign Member elected .............. if
Foreign Correspondents elected ........ 2
— _76

1329

Vol. 53.] ANNUAL REPORT.

DEcEASED FELLOWS.

Compounders (7).

Brockbank, W., Esq. Miller, H., Esq.
Green, Prof. A. H. Penrose, J. F., Esq.
Hall, Captain Marshall. Roper, F. C. 8., Esq.

Lyall, G., Esq.

Resident and other Contributing Fellows (17).

Armstrong, W., Esq. Miller, Baron F. von.
Birch, R. W. P., Esq. Paulin, R., Esq.
Carrington, T., Esq. Pike, E. R., Esq.
Church, J., Esq. Prestwich, Sir J.

De Salis, W. F., Esq. Robertson, Dr. D.
Dorning, E., Esq. Slack, H. J., Esq.
Dymond, A. W., Esq. Thompson, F, A., Esq.
Gover, Rev. Canon W. Worth, ite Ne, lisa:

Litton, R. T., Esq.

Non-contributing Fellows (2).

Gough, Viscount. | Sharp, W., Esq.

Foreign Members (8).

Beyrich, Dr. H. E. Whitney, Prof. J. D.
Daubrée, M. A.

xix

Xx PROCEEDINGS OF THE GEOLOGICAL socieTy. [May 1897,

Frettows Resienep (18).

Bigge, M. R., Esq. Northcott, Dr. W. C.
Brickenden, Maj. R. T. W. L. Panton, Prof. J. H.
Coltman, W. B., Esq. Rowe, Rey. G. F. H.
Coltman, W. H., Esq. Sanford, W. A., Esq.
Frecheville, R. J., Esq. Savile, A. G., Esq.
Jolly, W., Esq. Spencer, W., Esq.
Leese, J., Esq. Waugh, H., Esq.
Mackay, J. C., Esq. Whitehead, J., Esq.
Newton, E. W., Esq. Wills, H. T., Esq.

Frettows Removen (3).

McKnight, F., Esq. Williams, R. H., Esq.
Ramsay, E. P., Esq.

The following Personage was elected from the List of Foregn Cor-
respondents to fill the vacancy in the List of Foren Members
during the year 1896 :—

Professor Albert Heim, of Ziirich.
The following Personages were elected Foreign Correspondents during
the year 1896 :—

Professor 8. L. Penfield, of New Haven, Conn., U.S.A.
Professor J. Walther, of Jena.

Wak essh) ANNUAL REPORT. xxi

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 Sir A. Geikie and
R. Lydekker, Esq., retiring from the office of Vice-President.

That the thanks of the Society be given to J. J. H. Teall, Esgq.,
retiring from the office of Secretary.

That the thanks of the Society be given to Horace T. Brown, Esq.,
Sir A. Geikie, Dr. J. W. Gregory, T. V. Holmes, Esq., and F. Rut-
ley, 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 :—

xu PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

OFFICERS AND COUNCIL.—1897.

PRESIDENT.

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

VICE-PRESIDENTS.

Prof. TaG: Bonney, D:Se., LL.D. FES.
Lieut.-General C. A. M*Mahon.

J.J. H. Teall, Esq., M.A., F.R.S.
Henry Woodward, LL.D., F.R.S.

BR. S.
J. E.

SECRETARIES.

Herries, Esq., M.A.
Marr, Esq., M.A., F.R.S.

FOREIGN SECRETARY.

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

TREASURER.

W.. ¢. Blantord, LL.D. F.E:.S:

H. Bauerman, Esq.

COUNCIL.
R. Lydekker, Esq., B.A., F.R.S.

W. T. Blanford, LL.D., F.R.S. Lieut.-General C. A. M°Mahon.
Prof. T. G. Bonney, D.Sc., LL.D., | J. E. Marr, Esq., M.A., F.R.S.

F.R.S.

Prof. H. A. Miers, M.A., F.R.S.

Prof. W. Boyd Dawkins, M.A., F.R.S. | Horace W. Monckton, Esq., F.L.S.
Sir John Evans, K.C.B., D.C.L.,| E. T. Newton, Esq., F.R.S.

LL.D., F.R.S., F.L.S.
F. W. Harmer, Esq.
R. 8. Herries, Esq., M.A.

A. Strahan, Esq., M.A.
J.J. H. Teall, Esq., M.A., F.R.S.
W. W. Watts, Esq., M.A.

Henry Hicks, M.D., F.R.S. W. Whitaker, Esq., B.A., F.R.S.

Rev. Edwin Hill, M.A.

Rev. H. H. Winwood, M.A.

Prof. E. Hull, M.A., LL.D., F.R.S. | Henry Woodward, LL.D., F.R.S.
Prot. W. Judd, C.B., LL.D. FBS;

ASSISTANT-SECRETARY, CLERK, LIBRARIAN, AND CURATOR,

L. L. Belinfante, B.Sc.

ASSISTANTS IN OFFICE, LIBRARY, AND MUSEUM.

W. Rupert Jones.
Clyde H. Black.

Vol. 53.] ANNUAL REPORT, Xxiil

LIST OF

THE FOREIGN MEMBERS

OF THE GEOLOGICAL SOCIETY OF LONDON, in 1896, *

Date of
Election.

1848. James Hall, Esq., Albany, State of New York, U.S.A.
1856. Professor Robert Bunsen, For. Mem. R.S., Hezdelberg.
1857. Professor H. B, Geinitz, Dresden. ;

1867. Professor A. Daubrée, For. Mem. R.S., Parts. (Deceased.)
1871. Dr. Franz Ritter von Hauer, Vienna.

1874. Professor Albert Gaudry, Paris.

1875, Professor Fridolin Sandberger, Wiirzburg.

1876. Professor H. E. Beyrich, Berlin. (Deceased.)

1877. Dr. Carl Wilhelm von Giimbel, Munich.

1877. Dr. Eduard Stiss, 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, Liége.

1880. . Baron Adolf Erik Nordenskiold, Stockholm.

1880. Professor Ferdinand Zirkel, Lezpzig.

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, Lille.

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. (Deceased.)
1888. Professor Eugéne Renevier, Lausanne.

1888. Baron Ferdinand von Richthofen, Berlin.

1889. Professor Ferdinand Fouqué, Paris.

1889. Geheimrath Professor Karl Alfred von Zittel, Munich.
1890. Professor Heinrich Rosenbusch, Hezdelberg.

1891. Dr. Charles Barrois, Lille.

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, New 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, S¢. Petersburg.

1896. Professor Albert Heim, Ziirich.

VOL. LIII. ¢

XXIV PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1897,

LIST OF
THE FOREIGN CORRESPONDENTS

OF THE GEOLOGICAL SOCIETY OF LONDON, rn 1896.

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., U.S.A.
1882. Professor Louis Lartet, Toulouse.

1882. Professor Alphonse Milne-Edwards, Paris.

1884. M. Alphonse Briart, Morlanwelz.

1884. Professor Hermann Credner, Leipzig.

1884. Baron C. von Ettingshausen, Gratz. (Deceased.)
1887. Senhor J. F. N. Delgado, Lisbon.

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.

i890. M. Gustave F. Dollfus, Paris.

1890. Herr Felix Karrer, Vienna.

1890. Professor Adolph von Kénen, Géttingen.

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.

1893. M. Ed. Rigaux, Bowlogne-sur-Mer.

1898. Dr. Sven Leonhard Térnquist, Lund.

1898. 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.

1896, Professor S. L. Penfield, New Haven, Conn., U.S.A.
1896. Professor J. Walther, Jena.

— —— A i

a

Vol: 53. | ANNUAL REPORT. XXV

AWARDS OF THE WOLLASTON MEDAL

UNDER THE CONDITIONS OF THE ‘DONATION FUND’

ESTABLISHED BY
WILLIAM HYDE WOLLASTON, M_D., F.R.S., F.G.S., 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. Mr. William Smith. 1866. Sir Charles Lyell.
1835. Dr. G. A. Mantell. 1867. Mr. G. Poulett Scrope.
1836, M. Louis Agassiz. 1868. Professor Carl F. Naumann.
1837. eee T. P. Cautley. 1869, Dr. H.C. Sorby.

Dr. H. Falconer. 1870. Professor G. P. Deshayes.
1838. Sir Richard Owen. 1871. Sir A. C. Ramsay.
1839. Professor C. G. Ehrenkerg. | 1872. Professor J. D. Dana.
1840. Professor A. H. Dumont. 1873. Sir P. de M. Grey Egerton.
1841. M. Adolphe T. Brongniart. | 1874. Professor Oswald Heer.
1842. Baron L. von Buch. 1875. Professor L. G. de Koninck.
1843, M. Elie de Beaumont. 1876. Professor T. H. Huxley.

M. P. A. Dufrénoy. 1877. Mr. Robert Mallet.
1844. Rev. W. D. Conybeare. 1878. Dr. Thomas Wright.
1845. Professor John Phillips. 1879. Professor Bernhard Studer.
1846. Mr. William Lonsdale. 1880. Professor Auguste Daubrée.
1847. Dr. Ami Boué. 1881. Professor P. Martin Duncan.
1848. Rev. Dr. W. Buckland. 1882. Dr. Franz Ritter von Hauer.
1849. Sir Joseph Prestwich. 1883. Dr. W. T. Blanford.
1850. Mr. William Hopkins. 1884. Professor Albert Gaudry.
1851. Rev. Prof. A. Sedgwick. 1885. Mr. George Busk.
1852. Dr. W. H. Fitton. 1886. Professor A. L. O. Des
1853. M. le Vicomte A. d’Archiac. Cloizeaux.

M. E. de Verneuil. 1887. Mr. J. Whitaker Hulke.
1854. Sir Richard Griffith. 1888. Mr. H. B. Medlicott.
1855. Sir H. T. De la Beche. 1889. Professor T. G. Bonney.
1856. Sir W. E. Logan. | 1890. Professor W. C. Williamson.
1857. M. Joachim Barrande. 1891. Professor J. W. Judd.
1858 Herr Hermann von Meyer. | 1892. Baron Ferdinand von

‘| Mr. James Hall. Richthofen.

1859. Mr. Charles Darwin. 1898. Professor N. 8. Maskelyne.
1860. Mr. Searles V. Wood. 1894, Geheimrath Professor Karl
1861. Professor Dr. H. G. Bronn, Alfred von Zittel.

1862. Mr. R. A. C. Godwin-Austen. | 1895. Sir Archibald Geikie.
1863. Professor Gustav Bischof, 1896. Dr. Eduard Siiss.
1864. Sir R. I. Murchison. 1897. Mr. W. H. Hudleston.
1865. Dr. Thomas Davidson.

c2

XXv1

PROCEEDINGS OF THE GEOLOGICAL SOCIETY.

AWARDS

OF THE

[May 1897,

BALANCE OF THE PROCEEDS OF THE WOLLASTON

1831,
1833.
1854.
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

Mr. William Smith.

Mr. William Lonsdale.
M. Louis Agassiz.

Dr. G. A. Mantell.
Professor G. P. Deshayes.
Sir Richard Owen.
Professor C. G. Ehrenberg.
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 Koninck.

Dr. 8. P. Woodward.

Drs. G. and F’. Sandberger.
Professor G. P. Deshayes.
Dr. 8. P. Woodward.

Mr. James Hall.

Mr. Charles Peach.

canes T. Rupert Jones.

Mr. W. K. Parker.
Professor A. Daubrée.
Professor Oswald Heer.
Professor Ferdinand Senft.
Professor G. P. Deshayes.

1865.
1866.
1867.
1868.
1869.
1870.
1871.
1872.
1873.
1874.
1875.
1876.
aks yye
1878.
1879.
1880.
1881.
1882.
1883.
1884.
1885.
1886.
1887.
1888.
1889.
1890.
1891.
1892.
1893.
1894.
1895.
1896.
1897.

FUND.’

Mr. J. W. Salter.

Dr. Henry Woodward.
Mr. W. H. Baily.

M. J. Bosquet.

Mr. W. Carruthers.
M. Marie Rouault.
Mr. R. Etheridge.

Dr. James Croll.
Professor J. W. Judd.
Dr. Henri Nyst.
Professor 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.
Mr. R. Lydekker.

Mr. O. A. Derby.

Mr. J. G. Goodchild.
Mr. Aubrey Strahan.
Mr. W. W. Watts.
Mr. Alfred Harker.
Mr. F. A. Bather,

.”

Vol. 53.]

ANNUAL REPORT.

XXVli

AWARDS OF THE MURCHISON MEDAL

AND OF THE

PROCEEDS OF THE ‘MURCHISON GEOLOGICAL FUND,

ESTABLISHED UNDER THE WILL OF THE LATE

SIR RODERICK IMPEY MURCHISON, Bart., F.R.S., F.G.S.

‘To be applied in every consecutive year in such manner as the Council
of the Society may deem 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.
1878.
1876.

1876.
1877.
1877.
1878.
1878.
1879.
1879.
1880.
1881.
1881.
1832.
1882.
1883,

1883.
1884,
1884.
1885.

1885.
1886.
1886.

Mr. 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. Goppert.
Medal.

Mr. John Young.

Dr. H. Woodward. Medal.

Mr. Martin Simpson.

Dr. Ferdinand von Romer.
Medal.

Mr. Horace B. Woodward.

Mr. W. Whitaker. Medal.

Mr. Clement Reid.

1887
1887
1888

1888.
1889.

1889.
1890.

1890.
1891.

1891.
1892.

1892.
1895.
1895.
1894.
1894,
1895.

1895.
1896.

1896.

1897.

1897.

. Rev. P. B. Brodie.

. Mr. Robert Kidston.

. Professor J. S. Newberry.
Medal.

Mr. Edward Wilson.

Professor James Geikie.
Medal.

Professor G. A. J. Cole.

Professor Edward Hull.
Medal.

Mr. E. Wethered.

Professor W. C. Brogger.
Medal.

Rey. R. Baron.

Professor A. H. Green.
Medal.

Mr. Beeby Thompson.

Rey. O. Fisher. Medal.

Mr. G. J, Williams,

Mr, W. T. Aveline.

Mr, George Barrow.

Professor Gustav Lind-
strom. Medal.

Mr. A. C. Seward.

Mr. T. Mellard Reade.
Medal.

Mr. Philip Lake.

Mr. Horace B. Woodward.
Medal.

Mr. 8. 8S. Buckman.

Medal.

Medal.

XXVili

PROCEEDINGS OF THE GEOLOGICAL SOCIETY.

[May 1897,
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 be of any country
or either sex) has deserved well of the Science,—‘not less than
one third of the annual interest [of the fund] to accompany the
Medal, the remaining interest to be given in one or more portions at
the discretion of the Council for the encouragement of Geology or
of any of the allied sciences by which they shall consider Geology
to have been most materially advanced, either for travelling expenses
or for a memoir or paper published, or in progress, and without refer-
ence to the sex or nationality of the author, or the language in which

any such memoir or paper may be written.’

1876. Professor John Morris. | 1888. Mr. A. H. Foord.
Medal. 1888. Mr. Thomas Roberts.
1877. Dr. James Hector. Medal. | 1889, Professor W. Boyd Dawkins.
1877. Mr. W. Pengelly. Medal.
1878. Mr. G. Busk. Medal. 1889. M. Louis Dollo.
1878. Professor W. Waagen. 1890. Professor T. Rupert Jones.

1879.

Professor Edmond Hébert.

Medal.

Medal. 1890. Mr. C. Davies Sherborn.
1879. Professor H. A. Nicholson. 1891. Professor T, M*Kenny
1879. Dr. Henry Woodward. . Hughes. Medal.
1880. Sir John Evans. Medal. 1891. Dr. C. J. Forsyth-Major.
1880. Professor F. A. von Quen- | 1891. Mr. G. W. Lamplugh.

stedt. 1892. Mr. G. H. Morton. Medal.
1881. Sir J. W. Dawson. Medal. | 1892. Dr. J. W. Gregory.
1881. Dr. Anton Fritsch. 1892. Mr. E. A. Walford.
1881. Mr. G. R. Vine. 1893. Mr. E. T. Newton. Medal.
1882. Dr. J. Liycett. Medal. 1893. Miss C. A. Raisin.
1882. Rev. Norman Glass. 1893. Mr. A. N. Leeds.

1882. Professor Charles Lapworth. | 1894. Professor John Milne.

1883, Dr. W.B. Carpenter. Medal. Medal.

1883. Mr. P. H. Carpenter. 1894. Mr. William Hill.

1883. M. E. Rigaux. 1895. Rev. J. F. Blake. Medai.

1884. Dr. Joseph Leidy. Medal. 1895. Mr. Percy F. Kendall.

1884, Professor Charles Lapworth. | 1895. Mr. Benjamin Harrison. -

1885. Professor H. G. Seeley. | 1896. Mr. A. Smith Woodward.
Medal. Medal.

1885. Mr. A. J. Jukes-Browne. 1896. Dr. W. F. Hume.

1886. Mr. W. Pengelly. Medal. 1896. Mr. C. W. Andrews.

1886. Mr. D. Mackintosh. 1897. Dr. G. J. Hinde. Medal.

1887. Mr. Samuel Allport. Medal. | 1897. Mr. W. J. Lewis Abbott.

1887. Rev. Osmond Fisher. 1897. Mr. J. Lomas.

1888. Professor H. A, Nicholson.

Medal.

WoL 54. ANNUAL REPORT, Xxix

AWARDS OF THE BIGSBY MEDAL,
FOUNDED BY THE LATE

Dr. J. J. BIGSBY, FBS. 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

1887.

much.’
1877. Professor O. C. Marsh. 1889. Mr. J. J. Harris Teall.
1879. Professor E. D. Cope. 1891. Dr. George M. Dawson.
1881. Dr. Charles Barrois. 1893. Professor W. J. Sollas.
_ 1883. Dr. Henry Hicks. 1895. Mr. Charles D. Walcott.
1885. Professor Alphonse Renard. | 1897. Mr. Clement Reid.

Professor Charles Lapworth.

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-Lavis. 1894, Mr. Charles Davison.
1888. Museum. 1896. Mr. J. Wright.
1890. Mr. W. Jerome Harrison, 1896. Mr. J. Storrie.

Ba O.8 PROCEFDINGS OF THE GEOLOGICAL socinty. [May 1897,

Estimates for

INCOME EXPECTED.

WoulpOSiGOMSe).. ne wae ei horse pete oe) ose cern 17L OG
Due for Arrears of Admission Fees .......... 88 4 0
Admissions Besa sieaph tht sp nea eee 240 0

—————— 3828 4 0
Arrears of Annual Contributions ............ 120. 0. 0

Annual Contributions, 1897, from Resident Fel-
lows, and Non-Residents, 1859 to 1861 ....1610

Annual Contributions in advance ..........+. 35
: —— 1765 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 ...... 20 <0: 2G
Dividends on £2800 London and South-Western
Railway 4 per cent. Preference Stock ...... 112 0 0
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.
IPRETETEMES UOEK: Eas. iow vu 4s hese alee eh saree 5116 O
— 328 16 0
Sale of Quarterly Journal, including Longman’s
ACCOMM. Sih MRR bate aig! els otis cma ens 150 00
Sale of Geological Map, including Stanford's |
ACCOUNE: on sear oe rmteeter sw okies whales se pink 500
Sale of Transactions, Library Catalogue, General
Index, Hochstetter’s ‘New Zealand,’ and List
of Fellows «..\) tu piney cee canoe on ue ince oD 1078
—- 160 0 0
2753 0 O
Balance against Society ........2..06: 50415 0O-
£3257 15 0

Note.—The following Funds are available for Extraordinary Expenditure.

£ Ssenee
Balance at the Bankers’, Dec. 81st, 1896 ............ccceceeccseccecensees 761 13 11
Balance in the Clerk’s hands, Dec. 31st, 1896 .........0...2.0+-00000 6 Ol

£168 “oO

Vol. 53.] FINANCIAL REPORT.

the Year 1897.

EXPENDITURE ESTIMATED.

LS.
House Expenditure:
ATES). 5: seacoaesrecocp eu seencet oc Heche caanasorocmcc 015 0
eM UIST ACH Adee sails Sita licievieduloceruie swasiontens 1510.0
eG hrIes Piety oe. ioe sseiaedasesqcneeeceaette 15 O20
MAS eee ewan ceemaeaeis satisetiaseicaseisiaciee'sswneaijonsenan 20 0 0
GOA e Lead Meso Srasee Locdlrwcdmognncipacce sealed 25 0.0
HMorntture and) Re painss.as<icaecasssssdeensecnseres ad 2050
House-repairs and Maintenance................6 50 0 O
mamta le Cleaminey ieapocenacassenpres voscnceconsdees Ld OF FG
NWashinoramd Sunmdries. ccc. ecnsenencicenciecoasetee 25 0 O
ear MCe bMS ite asst aisle gcliwtictoceceewcdesa ses 15 0 0
Salaries and Wages, ete. :
Agsishaith SCCECLAGY,. we. ascnaanceans dps areesausasenees 300 0 0
- Half Premium of LifeInsurance 10 15 0
PAGS S Ata MM DRATIAM joni sons). cs dodiaic eeisinessscieee cee 150 0 O
PRSSISBAMILY CLOTS, «5 ticisn dean's ole slisle'tadeceee vee paabeies 8 0 0
House Porter and Upper-Housemaid ......... i ae 10)
WmderKloOmseMmald: soos. ccocscecccdeescnseannsecsia 42 12 0
MARAT MISO oo a emoaeties cejseae ation aeewic vines aeaeneee d0 16 0
Charwoman and Occasional Assistance......... 10) 0.50
PCC OLIM GA TIGIS ME CO Nata studenten sleaincswmteeain dates 10 10 O
ibraevaCbooksand Bimdine) sy. cc. a.c0 «2's emer:
PGMS SHIEK esas claps av o'ete Gob els ial! 01S ale) vie) e Wn peepee Ee :
Office Expenditure :
DStALIOWET Ye acne ack scstieedasnetee tenemos ersen ones 2p OO
Miscellaneous Printing) 21s) cwsavdieewas eon 30 0 0
Postages and other Expenses ...............s0e00+ 907 O56
Publications: :
Geological Map) van. catscordusesstecnecmasneecse ses 1057040
Quantorly; Joprnaly...:.2.-sadenees speeder 900 O 0
Ft fe Commission, Postage,
HNGPAGAKESSING shea icatoie ste tesss- seeses 100 0 0
Record of Geological Literature ............... 100 0 O
Tiast, Of MoMOwe ocesestarw censor sotcuscet usin cee rss 35 0 0
Abstracts, including Postage ...........-..s000 110) OO
Index to Quarterly Journal (Vols. 1-50)...... 250 0 0
Electric Lighting Installation. (Remainder
payzble.as per Contract.) 1... .05644 tara Bi) Moy O
Completion of Redecoration of Society’s Apart-
TOMS Laan sa diaper Cr cts, «pt & crm oneal ae eee 400 0 0

XxXX1

Pe Cf
Dia: low O
Tae 5:0
Dy OO

Se Or nO
145.00
1255-00
9580 0 O
Gir lon.

£3257 15 0

W. T. BLANFORD, Treasurer.

January 26th, 1897.

XXXI1 PROCEEDINGS OF THE GEOLOGICAL sociETy. [May 1897,
Income and Expenditure during the
+

RECEIPTS.
£ ss. d. es
Balance in Bankers’ hands, 1 January,1896. 835 5 10

Balance in Clerk’s hands, 1 January,1896. 16 9 7

—— roy mes 15 eS)
CompositionGiggi, ae Aaa stin @ cusses & <oarmn n ie arora eee 2/0 1850
Arrears of Admission-fees.............. 69 6 O
Admission-Teasy Jt 2A Oe ek Ge ek 296... 2.0
et oe SCa0kS 60
Arrears of Annual Contributions). occ 5. a..c es sacs eke 127 nde se
Annual Contributions of 1896:
Resident Fellows ......... 1569 15 0
Non-Resident Fellows... 6 6 O
—— 15764 20
Annual Contributionstimpadyanes : <0. . 225... as ate 52: 10° 0
Taylor & Francis: Advertisements in Journal, Vol. 51.. 6 4
Publications :
Sale of Journals, Vols. 1-51 ...........seecees 63.747.
i Vol oes teiscecteetes eee [2° Goa
Bale of. Pramsachions: + cetenciessscanaceenincaee 14 0
Sale of Geological Literature ..............- £8
Sale of Library Catalogue .............cesseeee 16 0
Sale of Geological Map fT: «.....s....se0seceses 819
Sale of Ormerod’s Index..i.cs.iscscseeoascnees 3 0
Sale of Hochstetter’s ‘ New Zealand’ ...... 4 0
Saleiof daish Or Pellows: ......ccieciecnesetparus 13 0
tt See
Dividends on L. & N. W. Railway Stock .. 87 0 0
4 L. & 8. W. Railway Stock .. 108 5 4
a L. B. &8.C. Railway Stock.. 1410 0
és Midland Railway Stock .... 50 1 6
Fr. India's p. ce. Stock ........ Fou | es
= 5 ee
Income Tax:
Repayment of Tax under Schedule C for the year
SIO =96 ... 2 hei ee ete eee acer 7) ce ae
*Due from Messrs. Longmans, in addition to the
above, on Journal, Vol. 52/2200 22) A. s.cs- £60 410
{Due from Stanford, on account of Geological
ho) ir ca PA

We have compared this Statement
with the Books and Accounts presented
to us, and find them to agree.

(Signed) J. W. GREGORY, eee
HORACE W. MONCKTON, suaelas
January 26th, 1897.

£3128 0 73

aa

Mol. 53.) FINANCIAL REPORT.

Year ended December 81st, 1896.

aS) Ka orlelas asian)

OoOoew

PAYMENTS.
House Expenditure: Ea f
a USCS ae ie rd Bo er Oh Spon ne A DA Pig 5
PES PNSUPANCE. oo. 5a cune saree ete caeeuetes nee 15 0
Electric Lighting Installation .................. 218 15
Bile ine Pichiiim esc 53. 2s, anand coe sctesedses 11
FLD Caan coe ene CRIES A tne shear 28 6
Be ee Hee carat pa atin weciele vane ebee heaa emer w a dace 15 19
urine and Repairs ....0..c2.ccscasetecmsnne’ 27 4
Electric Lantern and Fittings...............06 63 7
House Repairs (including Redecoration of
HeABEATIOTG) VS. 2.108 dalvcst aYrcees ease cad oka cae 115 5
peruritien | (ClOAIN GE. .fosnceaaicse sae ieekste tae odt sas 10 15
Washing. andiSundries 2.2.5... 2a..cocsseeanesse- 23 15
Bem At NOGuAES, « s...ccc0c0deceeeneso once i domtaaictl 16 9
Salaries and Wages, etc. :
SHELA SECEEUAEY.. oa-.acves cect dvctten nas osece 300 0
- Half Premium of Life Insurance 10 15
Assistants in Library, Office, and Museum... 230 0
House Porter and Upper-Housemaid ...... 89 19
Dire Pomsenadid f 42:00 dees naestoacensence 43 19-
LDUISTIEG 1 aA Ree anne re ee ae 32 15
Charwoman and Occasional Assistance ...... 10-3
PREC OMIANIOIS BCCI Spa ocnenossvevtansassucne'ss Jamun 10 10
Official Expenditure :
SOM BEY... 2cme Se cue naimesonenie sian geieanan meee 25 19
Miscellancous. Printing” «...2.sds-aencaedas nee oe 30 19
Postages and Sundry Expenses ............... 78 18
traby OS «52.87 tne cite ae os Tae Cakes a Pee
Publications :
Jonna Vols LM c rs cowie bel an depots Soca 8 16
Si MOL er Wr as see heat 911 15 5
- », Commission,
Postage,and Addressing. 92 17 11
—— 1004 13
Record of Geological Literature ............ 96 3
Jhistot Mellows ee. cusses ornweesenus Gleannan 35 18
Abstracts, including Postage ...............06. 113 9

Index to Quarterly Journal (Vols. 1-50)... 156 15

OOw oO

Balance in Bankers’ hands, 31 Dec.1896.. 761 13 11

Balance in Clerk’s hands, 31 Dec. 1896 .. 6 9

W. T. BLANFORD, Treasurer.

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Vol. 53.] ANNIVERSARY MEETING—WOLLASTON MEDAL. XXXV11

AWARD OF THE WortAston MEDAL.

In presenting the Wollaston Medal to W. H. Huptzsron, Ksq.,
M.A., F.R.S., F.L.S., the Prestpeyt addressed him as follows :—

Mr. Huprteston,—

It is extremely gratifying to me that it has fallen to my lot
to present to you, on behalf of the Council of the Geological
Society, the highest award which it is in their power to bestow on
distinguished geologists. You have laboured long and assiduously
in the cause of science, and have enriched geological knowledge
in its chemical, mineralogical, paleontological, and stratigraphical
departments. The first paper which you communicated to this
Society appears to be that ‘On the Chemical Analysis of the
Cambrian Rocks,’ which you were good enough to undertake at
my request in the year 1875. You had previously communicated
papers to the Geologists’ Association—one on the Yorkshire Oolites,
and another, in conjunction with Mr. Hilton Price, on the Thames
Valley Deposits. Another valuable chemical paper should be referred
to, namely, ‘On the Chemical Composition of the Rocks of the Lizard,’
which appeared as an Appendix to a paper by Prof. Bonney in
1877; and in that year also you, in conjunction with Prof. Blake,
contributed a highly important paper to this Society on the Corallian
Rocks of England. The Addresses delivered by you as President
of the Geologists’ Association, of the Devonshire Association for the
Advancement of Science, Literature, and Art, and of this Society,
show much critical power and demonstrate your ability to convey
a great amount of valuable information in a limited space. You
are further to be congratulated upon having recently completed the
important memoir published by the Palzontographical Society—
‘A Monograph on the Inferior Oolite Gasteropoda,’—which contains
no less than 514 pages and 44 quarto plates. The great value of
your work amongst the Jurassic rocks is so generally admitted that
I need not refer to the other papers contributed by you to various
Societies.

In conclusion I can only say that it gives me very much pleasure
to hand to you this Medal, which is presented by the Council as a
token of their recognition of the eminent services rendered by you
to Geological Science.

XXXVIli PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

Mr. Hupteston, in reply, said :—

Mr. PresipENT,—

On this occasion my warmest thanks are due to the Council,
on whom the duty of awarding the Wollaston Medal has this year
devolved, for their generous interpretation of my past geological
career. ‘To have received a distinction such as the foremost geologists
of any country might be proud to accept, and to be enrolled in
that famous band of recipients which is headed by the Father of
English Geology, is indeed to me an unexpected honour and grati-
fication. If anything were needed to enhance the pleasure of the
moment, it is to be found in the circumstance that I receive the
Medal from the hands of an old friend and contemporary, whose
scientific career possesses so many points of resemblance with my
own. For, if I have done some work in Mesozoic geology, you, Sir,
are well known, both in Europe and America, for your researches
among the older Paleozoic rocks.

This particular award serves to show that researches concerning
the mineral structure of the earth are not necessarily limited to
professional enterprise, but that both the Council and the Society are
ready to recognize the utility of independent work, whether special,
or of a more general character. Our science has its ramifications
in so many others, that, whether we consider Geology in its tectonic,
its petrographical, or its paleeontological aspect, it is incumbent upon
those who cultivate it to endeavour to acquire, to some extent, a
knowledge of cognate subjects. Not that I would venture to lay
claim to the accomplishment of much original work in any of the
above departments ; although I may have contributed something
towards a knowledge of the stratigraphy and paleontology of
the Jurassic rocks of England, and more especially of my native
county.

During the last quarter of a century the Geological Society and
the Geologists’ Association have, each of them, afforded me a con-
genial scientific home. If in that interval it has been my good
fortune to have furthered the cause which we all have at heart, such
service has been more than repaid by the benefits derived from
mutual intercourse. Nor do I forget the advantages afforded by
my relations with the Paleontographical Society, whose resources
have been useful to more than one Wollaston medallist.

In offering my thanks once more to the Council and also to the
Fellows here present for the cordiality with which the Award has
been received, I may truly say that this Medal will always serve as

Vol. 53.] ANNIVERSARY MEETING—WOLLASTON DONATION FUND. XXXixX

an agreeable memento of my connexion with the Geological Society.
So long as I live, it will give me pleasure to take an interest in
geological questions, and if I cannot promise to participate very
actively in the work of the future, I may at least say, as regards
my past work, that this recognition of its merits is most ample, and
leaves nothing on my part to be desired.

AwarkD oF THE Woxtaston Donation Funp.

The Presrpent then handed the Balance of the Proceeds of the
Wollaston Donation Fund to F. A. Barner, Esq., M.A., addressing
him as follows :—

Mr. BatHEr,—

The Council of the Geological Society have voted you the Balance
of the Wollaston Fund as an expression of their appreciation of the
excellent work in Paleontology which you are carrying on, and
with a view to assist you in the original investigations on the
Crinoidea upon which you have expended both much labour and
capital.

From the time you left the University of Oxford and entered the
Geological Department of the British Museum in 1887, you have
specially studied this group of fossil organisms; and in a series of
some 27 papers you have not only described many interesting
Paleozoic and Mesozoic genera, but have proposed a method of
classification, based upon the arrangement of the plates, which will
be of the greatest assistance to all future workers.

The paper which you published in 1893 under the auspices of the
Royal Swedish Academy, Part I. of the Crinoidea of Gothland (4to.
10 plates, pp. 200), is a work which needs only to be seen and
studied to be appreciated, and has been most highly spoken of by
eminent paleontologists at home and abroad. I trust this recog-
nition by the Council of what you have already done may encourage
you to still greater efforts, so that it cannot for long be said that our
English Crinoidea still need a monographer.

Mr. Bartuer replied in the following terms :—
Mr. PrestpEnt,—

After serving the British Museum for two years, I decided to use
the knowledge thus gained, and the opportunities there offered
VOL. LIII. d

xl PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

for an exhaustive study of the British Fossil Crinoids, a task to
which I was further urged by my much-mourned friend, Herbert
Carpenter. I estimated that the work would take 15 years. Half
that time has now passed, and I have dealt with only a few genera
from a single formation. The preliminary studies and other duties,
toa few of which you, Sir, so kindly alluded, have contracted the
time at my disposal within bounds that I long to enlarge. It is
the more encouraging that my fellow-workers should honour thus
highly the little that I have done, for I am not ashamed to say that
the thought of these awards has been, and will be,

‘a spur to prick the sides of my intent.’

The student of science, however, should not think overmuch of
contemporary applause. If a paleontologist, he must wrestle with
his fossils, nor let them go until they have yielded all their secrets.
Laborious investigation, precise description, accurate and detailed
drawings: these are indispensable if he is to receive aught but
abuse from a posterity even more critical than ourselves. In the
continuance of work that strives, however inefiectually, to have
this character, the present Award will be a material and a welcome
aid.

AWARD OF THE Murcuison MEDAL.

In presenting the Murchison Medal to Horace B. Woopwarp,
Ksq., F.R.8., the Prusrpent addressed him as follows :—

Mr. Woopwarp,—

The Council have this year adjudged you the Murchison Medal,
with the sum of Ten Guineas, and it is peculiarly appropriate that the
Award should be made to one who has for so many years zealously
worked on that Geological Survey which Sir Roderick Murchison,
the founder of the Medal, so long and ably directed. It may not
be generally known that, like your esteemed father, the late
Dr. 8. P. Woodward, F.G.S. (who was our Sub-curator in 1839),
you also commenced your geological career (in November 1863) as
an Assistant in the Museum of the Geological Society, at Somerset
House. During the past 30 years of your labours as a field-
geologist, on the Geological Survey of England and Wales, your
experiences have been most varied. From Newton Abbot and

Se

Vol. 53.] | ANNIVERSARY MEETING—-MURCHISON MEDAL. xli

other parts of Devon, over East Somerset, the Bristol Coalfield,
and the Mendips, to the Geology of Fakenham and the country
around Norwich (where your grandfather, Samuel Woodward, the
‘ Norfolk Geologist,’ laboured so earnestly 70 years ago), to Essex and
the neighbouring drift-covered counties; from the Jurassic areas
of Britain south of the Humber to the far-distant Jurassic areas of
Sutherland and Skye,—all these and more have, in turn, claimed
your careful attention. Besides your very numerous Survey
memoirs, maps, and sections, all prepared with much skill, you
have given us a most helpful work, ‘ The Geology of England and
Wales.’ When President of the Norwich Geological Society, the
Norfolk Naturalists’ Society, and the Geologists’ Association, you
gave important addresses, and you have contributed numerous
separate geological papers, read here and elsewhere. In addition,
I must especially refer to the ever-ready help which you afford, in
your office at Jermyn Street (as resident geologist), to all those who
call upon you for information, help which has rightly earned for you
a large circle of grateful friends.

Mr. Woopwaprp, in reply, said :—

Mr. PrestipEnt,—

In thanking you, Sir, and the Council of this Society, for the
high honour which you have now conferred upon me, I cannot help
feeling that you have regarded with great generosity whatever I
have been able to accomplish. JI would pass by the Official or
professional work. That has always been a pleasure: it has also
been a duty. And I would rather believe that you have taken more
into consideration the extra-official or amateur work which has
been the labour of leisure hours. This much I would like to say,
in reference to the second edition of my ‘ Geology of England and
Wales, that the impulse which led to its production was the
ambition to render some service; and to do this in the way I
desired was to act somewhat independently, for I received no
encouragement from publishers. That their predictions were fully
justified adds considerably to the gratification with which, Sir, I
now receive this mark of distinction and approval from your

hands.

d 2

xii PROCEEDINGS OF THE GEOLOGICAL Society. [May 1897,.

AWARD oF THE Murcuison Gronogicat Funp.

The Prestpent then handed the Balance of the Proceeds of the
Murchison Geological Fund to 8. 8. Buckman, Esq., addressing”
him as follows :-—

Mr. Bucxman,—

Following in the steps of your father, Prof. James Buckman,.
you have devoted many years to the elucidation of the Paleontology
and Geology of the Lower Oolitic rocks of Dorset and neigh-
bouring counties. In paleontology, you have dealt with the
Pelecypods, the Brachiopods, and the Ammonites of the Inferior
Oolite and Bajocian, the last group especially in the monograph
now being published by the Paleontographical Society. Seeing that
accurate work in paleontology could not be accomplished without
equally detailed stratigraphy, you have investigated, with a minute-
ness before unattempted for Jurassic rocks, the unravelling of their’
geological history, and the Society has thus received from your’
hands an important series of papers, amongst which I may mention
those on the Cotteswold, Midford, and Yeovil Sands (1889); on
the so-called Upper-Lias Clay of Down Cliffs (1890); on the
Bajocian of the Sherborne District: its Relation to Subjacent and
Superjacent Strata (1893); and on the Bajocian of the Mid--
Cotteswolds (1895). To show their appreciation of the important
work which you have already accomplished, and in the hope that
you may continue to work on the lines which have yielded results:
so excellent, the Council have felt much pleasure in awarding
you the Murchison Fund. |

Mr. Bucxmay replied as follows :—

Mr. PREsIDENT,—

I scarcely know how to thank you for the honour which you’
have done me in the presentation of this Award, and for the far
too favourable manner in which you have spoken of such scientific
work as I have been able to accomplish. You have very kindly
alluded to my stratigraphical work, and have noticed its minuteness.
As regards this part of my labours I have a clear conscience: it
was undertaken for the purpose of understanding the genealogy of
Ammonites, and its minuteness is an absolute necessity thereto.
But when I think of the paleontological work to which you have:

Vol. 53.] ANNIVERSARY MEETING—LYELL MEDAL. xiii

referred, I feel considerable cause for dissatisfaction. Now that
some nine yearly portions have appeared in the volumes of the
Paleontographical Society, I ought to be approaching the end of my
labours, but I find that I am actually farther from that desirable
attainment than when I began, while I have far less opportunity
for continuous study. And when I look back at the earlier portion
of this work, I am quite dissatisfied with the survey. I must own to
serious mistakes, particularly that I had not sufficiently the courage
of my own opinions, and that I gave heed to the outcry about new
genera and species. That was a sad mistake; but I have amended
it in the later parts of my work. In this direction I have, however,
far more to perform. How much—or little—praise I may obtain
thereby I know not, but the fact that you have kindly given me
this Award as a recognition of my work encourages me to con-
fidently pursue my way. It is for such encouragement that I most
appreciate this Award; and I thank you sincerely for it.

AWARD OF THE LyEtt MEDAL.

In presenting the Lyell Medal to Dr. Gzorez Jennines Hinpz,
¥.R.S., the Presipent addressed him in the following terms :—

Dr. Hinp5,—

The Council of the Geologieal Society have awarded to you the
Lyell Medal, with the sum of Twenty-five Pounds, in recognition
of your valuable researches in paleontology and geology, but more
especially in reference to your discoveries of Fossil Sponges and
other minute bodies preserved in cherts, in various formations, and
the painstaking manner in which they have been elucidated by you.
The experience which you gained when working as a student under
Prof. H. A. Nicholson, in the University of Toronto, and later, under
Prof. K. A. von Zittel, in the University of Munich (where you ob-
tained your degree of Ph.D., for a dissertation on the Fossil Sponge-
Spicules from the Chalk of Norfolk), was an excellent beginning for
your subsequent more ripened work. I need only refer to your
memoirs on Conodonts from the Cambro-Silurian and Devonian
rocks of North America, Scotland, and the West of England, and to
your various papers, to show the great value of the original work
which you have done. In your ‘Catalogue of the Fossil Sponges in
the British Museum,’ and in your memoir on ‘ British Fossil Sponges,’

xliv PROCEEDINGS OF THE GEOLOGICAL socieTy. [May 1897,

in the Paleontographical Society, you have given us works of con-
siderable importance. You have also published many other valuable
papers which have added much to our knowledge, and all recognize
that you have placed yourself in the foremost rank amongst those
who have devoted themselves to the study of minute fossil organisms.
The Medal could not be more worthily bestowed than upon one who
has always so earnestly laboured for the advancement of truth, and
I have very great pleasure in handing it to you.

Dr. Hinpe, in reply, said :—
Mr. PRresipEnt,—

It gives me sincere gratification to receive at your hands the
Lyell Medal, remembering that it is intended, in the words of its:
liberal-minded Founder, as a mark of honorary distinction and as
an expression that the recipient ‘has deserved well of the Science.’
That so competent a tribunal as the Council of the Geological
Society regards my Paleontological work as meriting this recogni-
tion, is to me a source of lively satisfaction.

I can only regret that so much of the work which it is my aim
to accomplish still remains to be done: the encouragement which
you have given me to persevere will not, I hope, be without result,
but whilst the field of investigation is ever widening and the
materials are constantly accumulating, the capacity to keep level with
the work becomes, with the lapse of time, a diminishing quantity.

I wish here gratefully to acknowledge the large measure of help:
which has been freely given to me in the course of my work by my
brother geologists and on the part of the Society, and more par-
ticularly my indebtedness to my friend and indefatigable colleague,
Mr. Howard Fox, in working out our joint paper on the Radiolarian
Rocks of Devon.

For the kindly, sympathetic, and very generous terms in which
you, Sir, have referred to what I have done, I desire to express my
warmest thanks.

AWARD OF THE LyzLL GroLtogicaL Funp.

The Presipenr then handed one half of the Balance of the
Proceeds of the Lyell Geological Fund to W. J. Lewis Axzzort, Esq.,.
addressing him as follows :— |

Mr. ABBott,—

Some twenty years ago you read an important paper on the

Vol. 53.] ANNIVERSARY MEETING—LYELL GEOLOGICAL FUND. xlv

Formation of Agates before the Geologists’ Association, and since
then you have contributed much additional valuable information in
regard to their origin. For many years you have also been a
careful and energetic collector of fossil remains, and of the imple-
ments worked by early man; and the remarkable collection shown
by you at the recent Conversazione in the rooms of the Society
testifies to your keen and accurate discrimination. Your researches,
as shown in your paper on the Ossiferous Fissures in the Valley of
the Shode near Ightham, published in the Quarterly Journal of the
Society in 1894, and in other papers published in the Proceedings
of the Geologists’ Association, the Journal of the Anthropological
Institute, and ‘ Natural Science,’ have greatly added to the faunas,
and therefore to our knowledge of the history, of the Pleistocene
and early post-Pleistocene periods.

The Council in making this Award desire not only to express to
you their appreciation of the work which you have already done, but
hope that it may be an incentive to further researches. It gives me
much pleasure to place this Award in your hands.

Mr. Axsort replied as follows :—

Mr. PresipEnt,—

I am deeply grateful to you, Sir, and the Council of the Geolo-
gical Society collectively, for the great honour conferred upon me
in thus appreciating the results of my labours; and to you, Sir,
personally for the very kind, appreciative words with which you
have supplemented it. There is, doubtless, a great reward in store
for all those who in any way contribute to the stock of human
knowledge—a reward which comes with the discovery of anything
new. But, after all, there is something which is perhaps even
greater to frailly constituted humanity than that: it is to receive
such tangible proofs as this that others admit the value of one’s
labours. It comes as a potent antidote for weeks and months of
almost barren research, a grateful compensation for midnight oil
expended and pecuniary losses sustained, and a wholesome incentive
to renewed energy in the future. JI am all the more proud of the
honour conferred upon me, in that it is associated with the name of
the great Ambassador of ‘the Causes now in operation’: for assuredly,
if there is one branch of Geology more than another calculated to
make one realize the applicability of these, it is that in which I
have been chiefly engaged, where we stand one foot on to-day and
the other on yesterday, and note, with equal distinctness and certainty

xvi PROCEEDINGS OF THE GEOLOGICAL socrery. [May 1897,

in each, the effects not only of sea and storm, but of the very
zephyrs.

But while my labours are thus rewarded, it must ever be remem-
bered how much the value of my Pleistocene work has been enhanced
by the co-operation of my esteemed colleague Mr. E. T. Newton,
and I gladly welcome this opportunity of publicly expressing my
deepest obligations and warmest thanks to him for his great and
kindly assistance during the last sixteen or eighteen years. In
conclusion, I can only express the hope that the remaining years of
my life, stimulated anew by this Award, will be spent in the cause
which I have so much at heart, and that the result of my labours
may continue not only to give me pleasure, but prove interesting
and profitable to others.

The Presrpent then handed the other moiety of the Balance of
the Proceeds of the Lyell Geological Fund to JosrpH Lomas, Esq.,
addressing him as follows :—

Mr. Lomas,—

The Council of this Society have this year awarded to you a
moiety of the Proceeds of the Lyell Fund in testimony of the value
of your work, especially in regard to the Glacial Geology of the
neighbourhood of Liverpool, and of areas in North Wales, upon which
you have written no less than ten papers between the years 1886
and 1896. To enable you to check the accuracy of your conclusions
you have also made a study of glaciation in Switzerland and the
Ferée. As showing that you have not neglected other branches of
geology, I may mention also your paper on the Basaltic Dykes of
Mull in 1887, and on Fossil Plants from the Carboniferous in 1895.
Your recent election as President of the Liverpool Geological Society
testifies to the esteem in which you are held by your fellow-workers
in that city, where as a special Lecturer on Geology at University
College you are responsible for most important geological teaching.
It is now my privilege to be the means of handing you this Award,
with the hope that it may aid you in your further researches.

Mr. Lomas replied in the following terms :—

Mr. PResipent,—

You have expressed, in much too kind words, your appreciation
of my work in Glacial Geology. Recognizing that the first duty of

Vol. 53. ANNIVERSARY MEETING—BIGSBY MEDAL. xlvil

a student is to collect accurate data, I have done my best to observe
and record the phenomena in my own district. If these observa-
tions have contributed, even in a small degree, towards the eluci-
dation of a very difficult problem, I am amply rewarded.

We, of the Liverpool Geological Society, are proud to think that
four of our Presidents have been honoured by marks of distinction
bestowed on them by the mother Society. The encouragement
which these Awards have afforded cannot be over-estimated.
When I look down a list of those who have received this Award
in former years, I cannot but think that the stimulus given has
greatly influenced their subsequent careers. I trust that may be
so in my own case, and I shall always endeavour to prove that
your kindness has not been misplaced.

AWARD OF THE BresBy MEDAL.

In presenting the Bigsby Medal to Cremenr Rerp, Esq., F.L.S.,
the Presipent addressed him as follows :—

Mr. Rem,—

The Council of the Geological Society have awarded to you the
Bigsby Medal in recognition of the excellent work which you have
already accomplished, and in full confidence that it will encourage
you to continue those researches with unabated vigour. Since 1874,
when you joined the Geological Survey, you have been engaged
in mapping many areas and various formations, but you have
more especially directed your attention to Tertiary and Pleisto-
cene Geology, and your memoir, ‘ On the Geology of the Country
around Cromer,’ has become a classical work of reference. The
painstaking manner in which you have searched for evidences of
plant-remains from the Pleistocene deposits merits the thanks of
all, for the results have been truly remarkable and have enabled us
to realize far more clearly than was previously possible the climatic
conditions prevailing when they were accumulated. Besides the
Survey memoirs which you have written, you have found time to
contribute several important communications to this Society and
valuable special notes to the papers of other authors. I feel much
pleasure in being privileged to hand to you, on behalf of the Council,
this Medal; and I may be allowed to express the hope that you will

xlviil PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

continue with the same energy that has hitherto characterized you
to add to our knowledge of those special branches of the science
which you have already cultivated with so much success.

Mr. Ret, in reply, said :—
Mr. PREstpENT,—

The bestowal of this Award, for which I tender my warmest:
thanks to the Council, makes me feel that perhaps, after all, the
results of my work may not be so valueless as I have sometimes:
feared. No doubt, compared with the magnitude of the problems
which I have had before me, the results are very small; and, when
viewed as a whole, must seem disconnected. I may say, however, that
the published observations have more in common than would appear
at first sight. They are the outcome of a continued attack, from
different sides, of some of those problems, on the correct solution of
which geological progress so largely depends. I allude to the
question of the alternations of climate which have taken place in
bygone times; the relation of these alternations to the migration,
extinction, and variation of species, and to past changes in physical
geography; and lastly, to the question of the rapidity with which
such changes can succeed one another. In short, my somewhat
ambitious task has been that of seeking a base-line for the measure-
ment of geological time.

Towards the attainment of this end I have made but small
progress; yet, while following unaccustomed paths noteworthy
facts are constantly discovered, and many a line of research, almost
a failure from the point of view of the original enquiry, has yet
repaid the time and labour bestowed upon it. It is only, 1 am
afraid, on such minor questions that I have, as yet, been able to
throw any light. My problem still lies before me. _

Vol. 53.] ANNIVERSARY ADDRESS OF THE PRESIDENT. xlix

THE ANNIVERSARY ADDRESS OF THE PRESIDENT,

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

Since our last Anniversary Meeting it has been my painful
duty to announce from this chair the death of the revered and much-
beloved Father of the Society and a former President, Sir Joseph
Prestwich, and also that of a much-respected Member of the Council,
and Vice-President, Prof. A. H. Green.

We have further to lament the deaths of some distinguished
Foreign Members and Foreign Correspondents, namely :—M. Auguste
Daubrée, Prof. H. E. Beyrich, Prof. J. Dwight Whitney, and
Baron C. von Ettingshausen ; and also of several Fellows of the
Society who have done much for the advancement of science.

Sir JosrpH PreEstwicH, who was descended from an old Lanca-
shire family, was born at Pensbury, Clapham, on March 12th, 1812.
He was educated at various preparatory schools, and in Paris, and
finally at University College, London, which had then been only
recently established. His early taste for scientific investigation
was shown in the avidity with which he took up the study of
chemistry and natural philosophy, and it is interesting to note that
the love of experimental science first stimulated by the teachings of
Drs. Turner and Lardner, at University College, continued through-
out the whole of his life. Clearly this inclination, under ordinary
circumstances, would have led him to adopt a scientific profession
rather than a commercial calling; however, it was otherwise
ordained, and he had to join the business of his father, a well-
known wine-merchant in Mark Lane. With the house and business
he remained closely connected for nearly forty years. Happily,
his commercial avocations to some degree aided, instead of restrict-
ing, his pursuit of geological studies. He had to make frequent
visits to France and Belgium, in both of which countries he formed
lasting friendships with the leading geologists and palzontologists
of the day; and he made himself personally familiar with the
actual strata and fossils which they had described. Not only so,
but his business among the country connexions of the firm carried
him to nearly every part of the United Kingdom, and the hours
unclaimed by his engagements were enthusiastically devoted to the

1 PROCEEDINGS OF THE GEOLOGICAL socrETY. [May 1897,

study of the local geology of the districts which he visited. His
comprehensive eye enabled him rapidly to appreciate and to grasp
the leading features, topographical and geological, of most of the areas
which in those days possessed an exceptional geological interest ;
and those who in later years had the good fortune to accompany
him to such. spots were surprised to find how retentive was his
memory and how intimate was his acquaintance with every pit,
quarry, and rock-section that in any way illustrated the geological
problem under consideration.

His first papers were on the Gamrie Ichthyolites and Shells in
the Till of Banffshire, and on the Geology of Coalbrook Dale,
published in the Transactions of this Society in 1835. This was
followed by a series of papers on Tertiary Geology which are also to
be found in the Journals of this Society.

In the winter of 1858, Dr. Hugh Falconer urged upon Mr. Prest-
wich’s attention the desirability of investigating in the field the
evidences for the discoveries of M. Boucher de Perthes of flint
implements of prehistoric man in the gravel-deposits of the Valley
of the Somme, which were then somewhat doubtfully received, and
in April 1859 Mr. Prestwich proceeded to Abbeville, where he was
joined by Mr. John Evans. Thence they went to Amiens, and in
the gravel-beds of St. Acheul saw for themselves, still embedded in
its matrix, one of those implements of unquestionable human
workmanship, the asserted existence of which in the alluvial deposits
had met with so much doubt. The previous discoveries, thus
verified, and subsequently supplemented by researches conducted on
lines which could with confidence be laid down, soon led to an
entire revolution in the then existing ideas as to the antiquity of
man. In the Compte-rendu of the Société Géologique de France,
No. 15, Séance du 9 Novembre 1896, there is a feeling reference to
his long connexion with that Society. He was introduced into it in
1838 by Constant Prévost and Deshayes; he was therefore for 58
years a Member, and in 1895 he was elected a Vice-President.
His French geological work is referred to as being of the greatest
importance, and as being a model for all.

Mr. Prestwich was elected a Fellow of the Geological Society as
long ago as 1833, and in 1849 the Wollaston Medal was awarded to
him for his researches at Coalbrook Dale and in the London Basin.
He served the Society as Treasurer for many years, and as Presi-
dent for two years from 1870 to 1872. In 1853 he was elected a
Fellow of the Royal Society, afterwards serving on its Council, and

Vol. 53.] ANNIVERSARY ADDRESS OF THE PRESIDEN‘. li

in 1870 and 1871 he was a Vice-President of that Society. One of
the Royal Medals was awarded to him in 1865 for his contributions
to geological science.

While Prestwich gave his attention in the main to pure science,
he did not neglect the important applications of knowledge. By
his publication in 1851 of ‘A Geological Inquiry respecting the
Water-bearing Strata of the Country around London’ he came to be
recognized as the leading geological authority on the subject; and
in 1867 he was appointed a Member of the Royal Commission on
Metropolitan Water Supply. He also rendered valuable aid to the
country by acting on the Royal Coal Commission, in connexion
with which he furnished an exhaustive and at the same time
suggestive Report (published in 1871) ‘On the Probability of
finding Coal under the newer Formations of the South of England,’
—some of the anticipations in which he lived to see, at all events
partially, realized. In 1874 the Institution of Civil Engineers
awarded him a Telford Medal and Premium for his paper on the
‘Geological Conditions affecting the Construction of a Tunnel
between England and France.’ On June 29th of the same year he
was appointed Professor of Geology at Oxford in succession to the
late Prof. Phillips, and his inaugural lecture was published under the
title of ‘The Past and Future of Geology, 1875.’ In 1876, in
investigating the conditions for a better water-supply, he pointed
out that there was under Oxford an abundant source of mineral
water, allied to, but stronger than those of Cheltenham and Leam-
ington. In 1876 his elaborate paper on ‘ Submarine Temperatures,’
which reviewed all that had been done before the Challenger
expedition, appeared in the ‘ Philosophical Transactions.’ The vearata
questio of the ‘Parallel Roads of Glen Roy’ next engaged his
attention, and this was followed by several other papers, amongst
which may be mentioned those on ‘ Underground Temperatures’
and on ‘ Volcanic Action.’ In 1885 he was elected by the Institute
of France a Corresponding Member of the Academy of Sciences.
In 1886 the 1st vol. (Chemical and Physical) of his work on
Geology was published by the Clarendon Press. The 2nd vol.
(Stratigraphical and Paleontological), with a Geological Map of
Europe, appeared in 1888. In the same year the University of
Oxford conferred upon him the honorary degree of D.C.L. He was:
elected President of the International Geological Congress which
held its 4th Session in London in September 1888, and in 1894 he
was elected into the Reale Accademia dei Lincei of Rome.

jh PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

His latest papers read before the Geological Society relate to the
Preglacial drifts of the South of England, with a view to determine
a base for the Quaternary Series, and to ascertain the period of the
genesis of the Thames. It is also well known that, owing to some
recent discoveries, he had abandoned his previous views as to the
age of some of the deposits containing Paleolithic implements, and
inclined to the view that man occupied this country in Glacial if
not Preglacial times.

His marked individuality and stern determination to get at the
truth necessarily compelled him to enter into some amount of con-
troversy, but his generous and lovable nature prevented the possi-
bility of any feeling of bitterness. He was, moreover, a man of
deep religious reverence, and delighted in the contemplation of all
that was beautiful and wonderful in nature.

After his retirement from Oxford he resided for the most part at
his delightful country house, Darent Hulme, Shoreham, Kent, which
he built in accordance with his own tastes some 28 years ago,
and every room and wall of which brought to mind some subject of
geological interest either in material or decoration. There he
actively continued his scientific labours, efficiently aided and cared
for by a loving wife, the niece of his old friend Dr. Hugh Falconer.
In the early part of last year the honour of knighthood was con-
ferred upon him by Her Majesty, but he was too feeble in health
to accept it in person. He died on June 23rd, and was buried in
the churchyard of Shoreham, near Sevenoaks. The funeral was
attended by a large number of representative men of science, who
had enjoyed the privilege of his friendship. |

His almost life-long friend, Sir John Evans, to whose sympa-
thetic notice in the Proceedings of the Royal Society I am
indebted for several of the foregoing statements, closes it with the
following remarks:—‘ Of his personal amiability, his devoted
friendship, and his charm of manner this is hardly the place to
speak; but all those with whom he was brought into contact will
agree that in Sir Joseph Prestwich we have lost not only one of the
great pillars of geological science, but a geologist whose mind was
as fully stored with accumulated knowledge as that of any of his
contemporaries, and one who was always ready to place those stores
generously and freely at the disposal of others.’

The death of Prof. A. H. Grezn on August 19th, 1896, removed
from among us one of the most respected and accomplished Fellows

Vol. 53.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lili

of the Society, and an active Member of the Council. He was
elected a Fellow in 1862, and at the time of his death he was
a Vice-President.

Alexander Henry Green was the son of the Rev. Thomas
Sheldon Green, who was for many years Master of the Ashby
Grammar School and a classical scholar of some repute. He
was born at Maidstone, October 10th, 1832, and educated at his
father’s school, Ashby-de-la-Zouch, and at Gonville and Caius
College, Cambridge. He was Sixth Wrangler in 1855, and was
elected Fellow of his College the same year. In 1861 he was
appointed an Assistant on the Geological Survey of England and
Wales, and in 1867 he attained the rank of Geologist. During the
time of his connexion with the Survey, he examined considerable
areas of the Jurassic and Cretaceous rocks in the Midland counties,
and of the Carboniferous rocks in Derbyshire, Yorkshire, and other
northern counties. Many Survey memoirs were written wholly or
in part by Mr. Green, among which are the ‘ Geology of Banbury ’
(1864), and the geological descriptions of the country around Stock-
port (1866), Tadcaster (1870), Dewsbury (1871), Barnsley (1878),
and Wakefield (1879). The memoir on the geology of North
Derbyshire, of which the first edition was published in 1869 and
the second in 1887, was written chiefly by Mr. Green. His most
important Survey work is the ‘Geology of the Yorkshire*Coalfield ’
(1878).

Mr. Green retired from the Geological Survey in 1874 on his
appointment to the Professorship of Geology in the Yorkshire
College at Leeds, to which was added, in 1885, the Professorship of
Mathematics in the same College. But he completed some official
Survey work after the time of his appointment at Leeds.

In 1876 he published a Manual of Physical Geology, a work
which has taken a leading place as a textbook for students and
teachers in this branch of the science; a third edition was issued
in 1883. |

For several years Prof. Green held the Lectureship on Geology at
the School of Military Engineering at Chatham. In the year 1886
he was elected a Fellow of the Royal Society, and served on its
Council in 1894-95. In 1888 he was appointed Professor of
Geology at Oxford, as successor to the late Sir Joseph Prestwich.
In 1890 he filled the office of President of Section C (Geology)
at the British Association, Leeds, and delivered the customary
address. Prof. Green also filled the offices of Examiner to the

liv PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

University of London and Assistant Examiner to the Science and
Art Department; he was, moreover, Examiner in Geology to the
University of Durham, and latterly for the Home and Indian Civil
Service. He had greatly endeared himself to his colleagues, and
his death at a comparatively early age has been a great loss to:
geological science.

By the death of Monsieur Aveustr Davsréz, which took place on
May 29th, 1896, in Paris, our Society has lost one of its most
distinguished Foreign Members. He was born at Metz (Lorraine)
on June 25th, 1814. After passing the Ecole Polytechnique he was
admitted into the Corps des Mines in 1834, and in 1838 was:
appointed Ingénieur des Mines in the Bas-Rhin, and Professor of
Geology and Mineralogy at the Faculty of Sciences of Strasburg, of
which he became Dean in 1852. In 1861 he was (almost unani--
mously) elected Member of the Academy of Sciences, in succession
to Prof. Cordier, whom he also succeeded as Professor of Geology
at the Natural History Museum, Paris; he was nominated In-
specteur-Général des Mines in 1867, and Director of the School of
Mines in 1872. Prof. Daubrée wrote more than 300 memoirs,
chiefly on geological and mineralogical subjects, and on investiga-
tions allied thereto, such as the permeability of rocks by water and
the effects of such infiltration in producing volcanic phenomena,
the relation between thermal waters and the rocks whence they
flow, the composition of meteoric masses anc their classification
in accordance therewith. He was also distinguished for the
long-continued and sometimes dangerous experiments which he.
conducted in order to ascertain to what extent it was possible artifici-
ally to imitate the natural production of rocks. Prof. Daubrée had:
been President of the National Agricultural Society of France,
Honorary President of the French Alpine Club, President of the
Academy of Sciences, of the Geological, the Gecgraphical, and the
Mineralogical Societies of Paris, Honorary Ph.D. of Bologna and.
of Halle, Foreign Member of the Royal Society of London, of the
Mineralogical Society, of the Reale Accademia dei Lincei, of the
Academies of Bologna, Boston, Brussels, Copenhagen, Gottingen,.
Munich, Philadelphia, St. Petersburg, and Turin, of the Scientific
Society of Batavia, and of the American Institute of Mining.
Engineers. He was also a Grand Officer of the Legion of Honour,
Grand Cross, Grand Officer and Commander of numerous foreign
Orders. Prof. Daubrée was elected a Foreign Member of this.

Vols 35] ANNIVERSARY ADDRESS OF THE PRESIDENT. ly

Society in 1867, and to him was awarded the Wollaston Gold Medal
in 1880. He was greatly esteemed and honoured by his fellow-
workers in science and those who had the privilege of his
acquaintance.

Dr. Hetnricn Ernst Beyricu, who was elected a Foreign Member
of this Society in 1876, died on July 9th, 1896. He was born
on August 31st, 1815, at Berlin, and received his education at the
Greyfriars Gymnasium. He entered the University at the early
age of 16, and there he commenced the study of various branches
of physical science, and was especially trained by Ch. S. Weiss
in mineralogy and geognosy. Already at that time led to see the
essential value of paleontology in stratigraphical investigations, he
gave himself up to a course of study at Bonn, where, under Goldfuss
and Noggerath, his knowledge was much extended. With the same
laudable object in view he undertook during two years long journeys
through Germany and France, and in 1837 he obtained his degree
of Doctor at Berlin.

Soon after the conclusion of his studies, Beyrich obtained
practical employment in the Mineralogical Museum of the Berlin
University, and after the death of Weiss in 1857 he was entrusted
with the same position as Director of the Paleontological Collec-
tion. On the death of Rose in 1875 he became Director of the
United Museums, and continued until towards the end of his 80th
year to be the lead . of this new organization.

Dr. Beyrich also obtained in 1865 the position of Professor of
Geology and Paleontology after having already, in 1853, been
elected a Member of the Berlin Academy. The particular branches
of science dealt with in Dr. Beyrich’s works relate principally to
palxontology and stratigraphy. His comprehensive knowledge,
and especially his intimate acquaintance with the neighbourhoods
of the Rhenish mountains, of the Harz mountains, and the Flotz
mountains in Silesia, as well as his innumerable studies in Alpine
districts, make Dr. Beyrich’s opinions in these branches of science
most valuable. His great success as a teacher, his wide knowledge,
and his power of organization placed him in the foremost rank of
German geologists.

Prof. Jostan Dwient Wauuitney, the well-known American
geologist and a Foreign Member of this Society, was born at North-
ampton, Massachusetts, on November 23rd, 1819. He graduated

VOL, Lill. é

lvi PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

at Yale in 1839, and then spent six months in the chemical
laboratory of Dr. Robert Hare in Philadelphia. In 1840 he joined
the Survey of New Hampshire as assistant geologist under Mr. C. T.
Jackson. Two years later he went to Kurope, and pursued his
studies in chemistry, geology, and mineralogy. On his return to
America in 1847 he investigated the geology of the Lake Superior
region, being appointed with Mr. J. W. Foster to assist in making a ~
geological survey of that district. Ultimately the completion of the
survey was entrusted to Mr. Whitney and Mr. Foster, who published
a ‘ Synopsis of the Explorations of the Geological Corps in the Lake
Superior Land District in the Northern Peninsula’ (Washington,
1849), and a ‘ Report on the Geology and Topography of a Portion
of the Lake Superior Land District in the State of Michigan’ (1850-
51). Mr. Whitney then travelled for two years through the States
east of the Mississippi for the purpose of collecting information as to
the mineral wealth of the country. This led to his book ‘ The
Metallic Wealth of the United States described and compared with
that of other Countries’ (Philadelphia, 1854). In 1855 he was
appointed State Chemist and Professor in the Iowa University, and
was associated with Mr. James Hall in the geological survey of that
State, of which he published an account. From 1858 to 1860
Prof. Whitney was engaged on a geological survey of the plumbiferous
region of the Upper Missouri in connexion with the official surveys of
Wisconsin and [linois, and he wrote in collaboration with Mr. James
Hall a ‘ Report on the Geological Survey of the State of Wisconsin ’
(Albany, 1862). Prof. Whitney was appointed State Geologist
of California in 1860, and conducted a topographical, geological,
and natural history survey of that State till 1874, when the State
Legislature discontinued the work. Besides various pamphlets and
annual reports, Prof. Whitney issued ‘Geological Survey of
California’ (six vols., Cambridge, 1864-70). In 1865 he was
appointed Professor of Geology at Harvard University, and retained
the chair till his death. The honorary degree of LL.D. was con-
ferred on him by Yale in 1870. Prof. Whitney was one of the
original members of the National Academy of Sciences named by
Act of Congress in 1863, but he subsequently withdrew from that
body. He was a member of a large number of scientific bodies both
at home and abroad, and was a contributor to the ‘ American Journal
of Science,’ the ‘North American Review,’ and many other
periodicals. He translated Berzelius’s ‘ Use of the Blowpipe’
(Boston, 1845), and he wrote a guide-book to the Yosemite Valley

Vol. 53.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lvii

(San Francisco, 1869). It isa significant testimony to his scientific
eminence that Mount Whitney, the highest mountain in the United
States, is named after him. His library of geological and geo-
graphical books is famous in the United States. He was elected
a Foreign Correspondent of this Society in 1872, and a Foreign
Member in 1887. He died on August 19th, 1896.

Baron Constantin von LErrryesHavsen died at Graz on
February 1st, 1897, at the age of 71. He was originally a
Doctor of Medicine, but devoted all his time and energies to
botany and paleontology. In 1876 he was summoned to London
to prepare a palzobotanical collection at the Natural History
Museum, and subsequently he was repeatedly here re-arranging
collections in the Museum. He was the author of several works
on botanical subjects, and wrote a large number of papers, which
were published in the Proceedings of the Royal Society and of
this and other learned Societies. He held, up to the time of his
death, the Professorship of Botany in the University of Graz,
and was elected a Foreign Correspondent of this Society in 1884.
Previously to this, in 1882, an Award from the Barlow-Jameson
Fund had been made to him in recognition of the value of his
work in paleobotany.

Viscount Goveu, F.L.S., was born on January 18th, 1815.
He was the son of Field-Marshal Hugh Gough, who brilliantly
distinguished himself in the field in India and annexed the Panjab
to the British dominions. After graduating B.A. at Trinity College,
Dublin, in 1836, and M.A. in 1840, he entered the Army; and
after spending some time in the Grenadier Guards he went on active
service, and acquitted himself in China with much distinction. He
was elected a Fellow of this Society in 1850, was Vice-President
of the Royal Dublin Society, and always took an active interest
in science. Viscount Gough died at his residence, Booterstown,
Co. Dublin, on June 2nd, 1895.

Jabez Cuurcu, M.Inst.C.E., who was elected a Fellow of this
Society in 1881, was born at Chelmsford in 1845, and was the son
and grandson of well-known engineers bearing the same name.
He designed and constructed many important works, chiefly in
connexion with the water-supply to large towns. He was for two
years in succession (1882 and 1888) President of the Society of

e2

lvili PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

Engineers. Upright and honourable in all his dealings, he was:
deservedly esteemed both professionally and privately. Mr. Church
ed at his residence in Kensington, on March 20th, 1896.

MarsHatL Hatt, late Captain in the Royal East Middlesex’
Militia, J.P. for Wilts, F.C.S., etc., was born in London ow
February 6th, 1831, and died at Parkstone, Dorset, April 14th, 1896.

As the only child of an eminent physician and physiologist, he
was brought up in an atmosphere of science from early days, and
it is to this circumstance that his penchant for things scientific was:
in a great measure due. Thus, he was at all times very handy
with his microscope, which he found useful both in his chemical
and mineralogical investigations. Besides his interest in science,
mountaineering and yachting had strong attractions for him, and it
was these three factors which largely influenced his career.

No one science could claim his exclusive allegiance; but he
evinced an interest in geology when he became a Fellow of the
Geological Society in 1866, most probably at the suggestion of his
intimate friend, Morris. Shortly after taking this step a brief
notice from his pen, in the ‘ Geological Magazine,’ showed that he
had already begun to interest himself in the glaciers of Norway,
as he claimed to have made a rough survey of ice-tracts at the end
of fiords where no yacht had ever been seen before.

Probably the best thing that Marshall Hall ever did for scientific
investigation was by organizing the cruise of the ‘Norna’ in 1870.
It is true that on this occasion he was ably seconded by two re-
markable men, Saville Kent and Edward Fielding, to the former of
whom especially the scientific credit of this most successful essay
in marine zoology was due. Still, it was on the initiation, and
mainly at the expense, of Marshall Hall that these results were
obtained ; and they are all the more striking when we remember
that this expedition took place three years before the Challenger
started on her memorable voyage.

A few years afterwards (1874) we find Marshall Hall, still full
of enthusiasm, making a proposal in the Geological Magazine for
a ‘Swiss Geological Ramble’; and he asks the then President of
the Geologists’ Association (Dr. Woodward) what he would think.
of this extended excursion. Two years subsequently he was busily
engaged, in conjunction with Sorby, Haughton, Heddle, and others,
in founding the Mineralogical Society. The first contribution to
the Journal of that Society (August, 1876) is a short note written:

Vol. 53.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lix

by himself and Clifton Ward ‘ Upon a Portion of Basalt from the
Mid-Atlantic.’

From time to time he contributed short papers to the Mineralogical
Society, not forgetting to suggest collaboration among mineralogists.
As he was now for the most part resident in Switzerland, the rocks
of the Val d’Anniviers and the Saasthal supplied him with a congenial
theme. Here both his chemical knowledge and his climbing pro-
pensities were of use. Thus, in 1882 he narrates how he traced
certain euphotides and serpentines to an aréte, some 10,000 feet
high, descending from the Allalinhorn, and he compares the rocks
thus observed i situ with transported masses occurring in the
neighbourhood of Veytaux and Geneva.

More recently, and since he came back to England, Marshall Hall
returned with renewed ardour to an old love—the study of glaciers.
His Alpine experiences helped him here. In this connexion his
friend and fellow-worker, Prof. Forel, writes! that Hall had often
contributed original notes to the reports on glacier-variations
issued by himself. Later, in 1891, when living at Parkstone,
Marshall Hall continued to follow up this subject with great eager-
ness, and obtained from the Alpine Club the formation of a com-
mittee charged with the care of studying the oscillations of the
glaciers in different parts of the British Empire. In 1893 he
contributed a short paper to the Geological Magazine on ‘Glacier
Observations, more especially Colonial,’ being the substance of two
articles which had already appeared in the Alpine Journal. He was
successful also in interesting the Colonial authorities in his scheme.
Finally, in 1894, at the International Geological Congress Meeting
at Zurich, he initiated the formation of the Commission Inter-
nationale des Glaciers, being himself elected representative for Great
Britain and the Colonies.

A wide field had in this way been found for the exercise of his
energies, and there seemed every prospect that he might continue
to do much good work, when, to the great sorrow of his family and
numerous friends, he was carried off, after a short illness, at the
age of 65, just as his plans for the universal study of glacier-action
were beginning to bear fruit.

Marshall Hall is not to be estimated merely by his writings,
which, like his speeches, were for the most part exceedingly brief.
His strength rather lay in his faculty of bringing men together,
and for this purpose his genial disposition and agreeable manners

1 “In Memoriam,’ Alpine Journal, Aug. 1896, p. 176

lx PROCEEDINGS OF THE GEOLOGICAL soclETY. [May 1897,

eminently qualified him. In the heyday of life he discharged these
functions in a generous and hospitable spirit. Unfortunately, as
time went on, his physical infirmity of deafness, in conjunction with
other causes, tended to withdraw him from society at large, though
never from social intercourse. To the last he struggled bravely
against all these difficulties, frequently busy, but, as he says in
a letter written a few months before his death, grown older and less
inclined to work. ‘Not that I am often idle,’ he remarks; ‘things
come in all of a heap, then comparative repose, then more work..
There will not be much to show for sundry years, even if I get
folks to do anything systematic. So far, the New Zealanders are
my best men.’

Those sundry years he was not destined to realize, and now
that the originator is gone will the work be continued ?

[W. H. H.]

Wittiam Sarr, M.D., F.R.S., who was elected a Fellow of this
Society in 1840, was born on January 21st, 1805, at Armley, in the
parish of Leeds, where, and at Little Horton and Bradford, his
family had resided for several centuries. In 1821 his uncle,
William Sharp, the leading surgeon in Bradford, took him as a
pupil, and subsequently, in 1825, he was taken as pupil by the
second William Key of Leeds, his uncle’s cousin, and remained with
him until Oct. 1st, when his hospital career commenced in London
at Guy’s and St. Thomas’s Hospitals, where Sir Astley Cooper
was chief. In 1826 he obtained from the Society of Apothecaries
his licence to practise, at that time the only legal qualification.
Remaining at the hospitals another year, he obtained the diploma
of the Royal College of Surgeons; this was in 1827, He then went
to Paris and attended the University lectures at the Sorbonne. In
1828 he returned to Bradford as his uncle’s assistant; in 1829 he
was elected Surgeon to the Infirmary; in 1833, on his uncle’s
death, he succeeded him and had a large practice. In 1843 he
resigned his practice and went to Hull, where he gave lectures on
chemistry during the winters; but four years later he removed to
Rugby for the purpose of placing his sons under Dr. (afterwards
Archbishop) Tait, then headmaster of Rugby. Finding that natural
science had no place in the teaching at Rugby, he urged its intro-
duction on Dr. Tait. The latter was quite willing to make the
experiment, provided Dr. Sharp would become the first teacher,
and, under the style of ‘ Reader in Natural Philosophy,’ Dr. Sharp
conducted the classes during 1849 and 1850. ‘If,’ said the late

Vol. 53.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lxi

Judge Hughes, ‘ Tait had done nothing else at Rugby than appoint-
ing Sharp, not without difficulty, as Reader in Natural Philosophy,
he would have deserved the gratitude of every Rugby man.’
Dr. Sharp was also one of the early supporters of the establishment
of local museums, and read a paper on the subject before the British
Association in 1839. His more important writings were on the
various schools of medicine, and appeared at intervals under the
title of ‘ Essays in Medicine.’ . He died in April 1896.

Hewry James Stack, F.R.M.S., who was elected a Fellow of this
Society in 1849, was born on October 23rd, 1818, and died on June
16th, 1896. He was educated at Dr. Evans’s School, North End,
Hampstead, and at the age of seventeen he entered a -wool-broker’s
office in the City, in which he speedily became a partner, but he
retired in 1846, finding the business uncongenial to his literary and
scientific inclinations. He then devoted himself to legal and forensic
studies, and was in due course ‘called’; but, although a keen
debater and intensely fond of either a scientific or political discussion,
he never practised at the bar.

Among his numerous scientific papers three only bear directly
on geology, namely: ‘On Coccoliths and Coccospheres in Reigate
Sandstone’; ‘ Notes on the Comparative Geology of the Earth
and Moon’; and ‘Life-Changes on the Globe’ Of the Royal
Microscopical Society he may be said to have been one of the
founders, and he filled in succession the offices of Secretary and of
President. His scientific papers mostly appeared in the ‘ Intellec-
tual Observer’ and ‘Student,’ and bear chiefly upon microscopical
research. Some of his work on Infusoria was published in a small
book entitled ‘ Marvels of Pond Life,’ which passed through three
editions.

Tuomas Carrineton, M.Inst.C.E., born on October 5th, 1841,
‘was the eldest son of the late Thomas Carrington, J.P., of Holy-
well House, Chesterfield. After studying for three years under
Dr. Ashby, with the view of obtaining a thorough knowledge of
chemical analysis, he was articled in 1859 to Mr. G. T. Woodhouse,
who was in practice as a civil and mining engineer at Derby and in
Westminster. In 1873 he was appointed by the Home Office one
of the three examiners, in the Yorkshire district, of candidates for
certificates of competency as managers of mines. Mr. Carrington
was one of the most prominent mining engineers in the Midlands,

‘

lxil PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

having been engaged for thirty years as umpire, arbitrator, or
otherwise in disputes between railway- and canal-companies and
colliery-owners, and his ability and sound judgment in highly
technical cases were widely recognized. He was specially retained
by the Midland Railway Company to advise on questions relating
to its large mineral traffic. He was elected a Fellow of this Society
in 1864, and died on June 27th, 1896.

Ricoarp Nicnoras Wortu was elected a Fellow of the Society in
1875. He wrote much on the geology of Devonshire, particularly
the neighbourhood of Plymouth, and was one of the most active
and respected members of the Devonshire Association for the
Advancement of Science, Literature, and Art, and was always most
ready to render assistance to those who desired to study the
districts with which he was familiar. His first paper appears to
have been published in vol. v. Trans. Devon. Assoc. 1872, and
in the Royal Society Catalogue of Scientific Papers fourteen
appear under his name up to 1883. The Quarterly Journal of
the Geological Society for 1876 contains a paper by him ‘On
certain Alluvial Deposits associated with the Plymouth Limestone.’
Another in 1886 ‘ On the Evidence of a Submarine Triassic Outlier
in the English Channel off the Lizard,’ and in 1889 ‘On the Elvans
and Volcanic Rocks of Dartmoor.’ He was a voluminous writer
on archeological subjects connected with the county of Devon, and
wrote several guide-books which have had a large circulation.

Mr. Worth died on July 3rd, 1896.

Eirias Dornine, M.Inst.C.E., born on January 25th, 1819,
was articled to the late Mr. William Benson, of Bury, in 1836.
After serving a pupilage of five years, he was engaged from 1841 to
1843 as resident engineer on the Bury Waterworks. Mr. Dorning
then commenced to practise on his own account in Manchester
as a civil and mining engineer, surveyor, and land agent. Asa
consulting engineer Mr. Dorning acted for the Earl of Derby, the
Earl of Sefton, the Earl of Wilton, and many other landowners in
the North. He was standing arbitrator for the Corporation of
Manchester. He was elected a Fellow of this Society in 1867,
and died on July 18th, 1896.

By the death of Baron Ferpinanp von Mitten, who was elected
a Fellow of this Society in 1882, Australia has lost one of her

Vol. 53. | ANNIVERSARY ADDRESS OF THE PRESIDENT. )xili

greatest scientific men, and the world in general a great botanist.
Ferdinand von Miller was born at Rostock in 1825, and was
educated for the medical profession at Schleswig and Kiel. He early
manifested a keen love of botany, and as soon as he had taken his
M.D. degree he made an exhaustive study of the flora of Schleswig-
Holstein, and became an active member of the German Association
for the Advancement of Science. Being threatened with phthisis, he
sought a more genial climate, and went to South Australia in 1847.
He made expeditions into the interior and prosecuted botanical
researches, especially into the mountain flora. He then acted as
botanist to the Gregory explorations in search of Dr. Leichardt,
returning from them loaded with botanical specimens. He was
then appointed director of the Melbourne Botanical Gardens, a
position which he retained until 1873, when he became Government
botanist, and devoted himself for the rest of his life entirely to
scientific work, producing a number of valuable treatises on botan-
ical subjects which gained him a world-wide reputation. The best
known of these are ‘Fragmenta Phytographie, ‘Flora Austra-
liensis, and ‘Plants of Victoria.” His ‘Select Extra-tropical
Plants’ is a unique work of its kind, cataloguing plants suitable
for culture in the southern part of Australia, with indications of
their uses. Altogether he published no less than forty volumes in
English, German, and Latin. When the International Geographical
Congress assembled in Vienna, five special votes of thanks were
awarded to men who had rendered exceptional services to science,
and F, von Miiller was one of the five. In 1861 he was elected
a Fellow of the Royal Society. In 1891 he was created an hereditary
baron by the King of Wiirtemberg and a Commander of the Order
of St. James of Portugal, and was afterwards made a Knight of
the Order of SS. Michael and George by Her Majesty the Queen.
He was a member of 150 learned societies in Europe and America,
President of the Australasian Association for the Advancement of
Science in 1890, and President of the Section of Pharmacology
at the second Meeting of the Intercolonial Medical Congress of
Australasia in 1889. He was the first to describe scientifically
the Eucalypti, of which he discovered thirty varieties, and proclaimed
their hygienic and therapeutic properties, disseminating their seeds
over the malarious districts of Europe. The Baron never married, and
lived a very simple frugal life, spending the whole of his income on
his scientific pursuits. His whole-souled devotion to his favourite
study and his indefatigable industry and inexhaustible patience

lxiv PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

were almost unique, and he combined in a remarkable manner the
thoroughness of the German with the practical good sense of the
English man of science: while his contributions to knowledge were
of the highest value as pure science, they were also of great
economic importance and helped to open up avenues of wealth to
many of his fellow-colonists.

He died on October 9th, 1896.

Davin Rosertson, the well-known Cumbrae naturalist, died at
Millport on November 20th, 1896, at the age of 90. He was
a native of Glasgow, but for the last 40 years he lived at Millport,
and devoted his attention to the study of natural history with so
much success that in knowledge of the fauna of the West of Scotland
he was not surpassed by any other naturalist. His collection of
specimens was very extensive and, indeed, unique. He worked for
long in a floating marine station called The Ark. In company
with Dr. John Murray, of the Challenger expedition, he dredged the
greater part of the Firth of Clyde for marine specimens. Mainly
through Dr. Robertson’s efforts the foundation-stone of a permanent
marine station was lately laid. Two years ago the University of
Glasgow conferred on him the degree of LL.D. He also held several
foreign diplomas. He was elected a Fellow of this Society in

LS.

Witr1am Armsrrone, who was elected a Fellow of the Society in
1866, died at the ripe age of 84, on Nov. 3rd, 1896, at Pelaw House,
near Chester-le-Street. He was perhaps the best known and most
experienced mining engineer inthe North of England, and throughout
Northumberland and Durham, where the chief work of his life was
done, he was known as the Father of the coal-trade. Born in
1812, he was educated at Dr. Bruce’s academy, Newcastle-on-Tyne,
and at Edinburgh University. He served his time with Mr. Nicholas
Wood, at Killingworth, Northumberland, and quickly took a place
in the first rank of the able body of mining engineers whose work
it was to open up and develop the coalfields of Northumberland
and Durham. He first came prominently into public notice in
connexion with the hard-fought strike of 1843, known as the
‘ wire-rope strike,’ when he practically fought for and won the
introduction of wire ropes into England for mining purposes.

The Rev. Wirt1am Gover died on Nov. 16th, 1896, at his residence
in Brighton, in his 79th year. He was formerly a scholar of Corpus

> Vel. 53.1] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixv

Christi College, Cambridge, and took his B.A. degree in 1841, pro-
ceeding M.A. in 1845. He was ordained, in the diocese of
Worcester, deacon in 1843 and priest in 1844. He held curacies
in Birmingham, at St. Andrew’s, Holborn, and at St. Pancras, and
was for a time chaplain to the late Lord Annesley. In 1852 he
became Principal of the Worcester, Lichfield, and Hereford Training
College at Saltley, a post which he held till 1871. In 1867 he
was appointed honorary canon of Worcester Cathedral.

He was elected a Fellow of this Society in 1866, and though he
does not appear to have written much on geology, those who were
acquainted with him know that he was keenly interested in the
science.

Witttam Farnworts died at his residence, the Manor House,
Sedgley, at the end of January 1897. He had been for many years
connected with the coal and iron trades of the Midland district,
where he was widely known. He was elected a Fellow of this
Society in 1885.

On some Recent EvIDENCE BEARING ON THE GEOLOGICAL AND
BrotogicaL History oF EARLY CAMBRIAN AND PRE-CAMBRIAN
TIMEs.

Ir is now fully admitted that a very great and important advance
in our knowledge of the conditions prevailing in early Cambrian and
pre-Cambrian times has been made during comparatively recent
years. Therefore it may be well occasionally, not only to summarize
the results arrived at, but also to call to mind how and by what
means these additions to our knowledge have been obtained. In
doing so, also, we may hope to awaken a desire to attack those
problems which still remain unsolved and to stimulate the desire for
further discoveries. J have limited the period for consideration to
the past 30 years, as there is in the fourth edition of ‘ Siluria,’
published in 1867, p. 22, a very clear statement of our knowledge
and the prevailing views held at that time concerning the pre-
Cambrian and Cambrian rocks and the early life-history of our
globe. |

Summaries of special work done amongst the early Cambrian
and pre-Cambrian rocks have appeared from time to time in the
addresses delivered from this chair; but it has occurred to me that:

Ixvi PROCEEDINGS OF THE GEOLOGICAL socleTy. [May 1897, .

a fairly connected history of the main results which have been
obtained during an extended period might not be altogether
unacceptable to the Fellows of the Society.

After describing the structure and order of the rocks in various
areas, Sir R. Murchison in the edition quoted preceeds to say :-—
‘ Observation has now taught us of what materials the fundamental
rocks of different countries consist. In Scandinavia, particularly in
the central and northern parts of Norway, there is every reason to
believe that, as in British North America, Bohemia, and the North-
west of Scotland, crystalline rocks of Laurentian age underlie all the
deposits to which the terms Cambrian and Silurian can be applied.
In Bohemia, however, as in Great Britain and portions of North
America, the lowest zone containing Silurian remains (“Zone pri-
mordiale ” of Barrande) is underlain by very thick basements of
earlier sedimentary accumulations of Cambrian age, whether sand-
stone, schist, or slate, which, though occasionally not more crystalline
than the fossiliferous beds above them, have as yet afforded only rare
indications of former beings. This is the important fact to which
attention is now directed; for in such instances the geologist
appeals to strata which have undergone little or no alteration.
In this enormous pile or series of early subaqueous sediment, com-
posed of mud, sand, or pebbles, the successive bottoms or shores of
a former sea, all of which had been derived from pre-existing
rocks, he has been unable, after many years of research, to detect
more than a very few traces of former creatures. But lying upon
them, and therefore evolved after them, other strata succeed, in
which clear relics of a primeval ocean are discernible; whilst these
again are everywhere succeeded by deposits containing many
organic remains of a more advanced nature. In this way, evi-
dences have been fairly obtained to show that the rocks bearing
the name of Laurentian and Cambrian constitute the sterile natural
bases of the rich deposits termed Silurian.’

It will of course be understood that the term Cambrian was
restricted by Sir R. Murchison to the rocks which were older
than the Lingula-Flags, including the Menevian beds, in which
Salter and myself had previously discovered a very rich fauna in
Wales. The actual line of division which was adopted in the
colouring of the Survey maps was first traced out at St. David’s
by Sir A. Ramsay in 1841, who refers to the fact in vol. iil.
Mem. Geol. Surv. (1866) p. 7, as follows:—‘In the same year, at
St. David’s, I traced a provisional line between the black and the

Vol. 53. ANNIVERSARY ADDRESS OF THE PRESIDENT. lxvit

purple slates, and this was afterwards adopted as the line between
the Silurian and Cambrian strata.’

The Longmynd Rocks up to a comparatively recent period were .
always included in the Cambrian, but of late years the tendency has
been to associate them with the pre-Cambrian. If they can be
proved to be without doubt of pre-Cambrian age, unusual interest
will be attached to them owing to the fact that many years ago
Mr. Salter found in them burrows of annelids which he described
under the name of Arenicolites didyma, and also what he considered
to be a part of a trilobite under the name of Paleopyge Ramsayi.

The Cambrian Period.

It had been shown by Salter and myself before the year 1867 that
a very rich fauna occurred in the Menevian beds, which rested directly
on the red, purple, and green grits and slates, in North and South
Wales; but up to that year no organisms had been found in the
latter, the only rocks recognized as Cambrian by Sir R. Murchison
and the Geological Survey. Curiously, however, in that year I found
in the red rocks underlying the Menevian beds at St. David’s a small
Lingula, and this was described in a paper by Mr. Salter and
myself at a meeting of the Geological Society on June 19th, 1867,
and fortunately in time for Sir R. Murchison to add the following
note in the Appendix (p. 550) to the edition of ‘Siluria’ which
contained the statement already referred to:—‘ At the meeting
of the Geological Society on June 19th, 1867, Mr. J. W. Salter
read an account of the discovery of a minute Lingulella in the red
Cambrian rocks of St. David’s, which there underlie the Primordial
Silurian (mihi). According to my view (and I am entitled to judge
by acquaintance with both districts), the rocks in which this small
fossil was found may be paralleled in age with the uppermost or red
portion of my original Cambrian of the Longmynd (1835),.’

This was the first admission on the part of the Geological Survey
that ‘ Cambrian ’ rocks, or those classed by them under that name
in Wales, contained any evidence of the life of that period. In
subsequent years I was able to show that the whole of the rocks
coloured as unaltered Cambrian at St. David’s to their very base
contained fossils, and that the seas in which the deposits had accu-
mulated must have teemed with life. Since then, through the
researches of Dr. Callaway and Prof. Lapworth in Shropshire, and of
the officers of the Geological Survey in the North-west of Scotland,

[xviii PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

we have obtained evidences of most interesting Lower Cambrian
faunas from those areas.. During the whole time when the Lower
Cambrian rocks were deposited it is quite evident that the general
conditions were favourable to marine life; but as the deposits must
have accumulated with comparative rapidity and in fairly shallow
water, there are few calcareous zones, and the range of typical
fossils is often great. The close of the pre-Cambrian period was
undoubtedly accompanied by great physical changes, which produced
very uneven land-surfaces, and the encroachment of the sea over the
land was therefore necessarily interrupted and irregular. This also
would in part account for the unusual range of some of the organisms,
for those which hugged the shores would still remain in some areas
while deeper-water forms might be almost close at hand. When it
is remembered also that the pre-Cambrian land contained an
unusual amount of loose and easily disintegrated volcanic material,
which would be carried by streams or rivers into narrow bays, the
cause of rapid accumulation becomes easily understood. In the
Lower Cambrian rocks hundreds of feet of sandstones and grits
constantly occur, with only here and there very thin seams of muddy
deposits. The beds also are so often ripple-marked that it is clear
that the depression did little more than keep pace with the accumu-
lation. When finer sediments occur, and there are signs of a pause
in the deposition, fossils are usually found in fair abundance and
with evidence of fresh arrivals on the scene.

All this is proof to my mind of the incoming of forms from
adjoining marine areas more suitable to their development than
these constantly changing shores, where the accumulation of |
materials was going on so rapidly. Though we count our Cambrian
deposits by thousands of feet, no one will venture, when he knows
the full circumstances under which they were accumulated, to say
that the majority of the animal forms now classed as characteristic
of that period were not equally so of much of the pre-Cambrian
period.

We may now fairly ask why it is that the pre-Cambrian rocks
do not contain evidences of the earlier faunas. This question
would have been much more difficult to answer a few years
ago than at present. Then all, or nearly all, pre-Cambrian rocks
were looked upon as metamorphosed sediments. Now all agree
that the pre-Cambrian rocks with which we are acquainted are
mainly of igneous origin—either intrusive or extrusive igneous
rocks. And the comparatively few rocks of sedimentary origin

Vol. 53.4 ANNIVERSARY ADDRESS OF THE PRESIDENT. bax

associated with them have been in most cases so profoundly altered,
and furnish also evidence of having been deposited in areas so greatly ©
disturbed, that it would hardly be possible to conceive circumstances
less favourable to the presence or the retention of any remnants of
the life of the period. When we all believed that the 20,000 or
30,000 feet tabled as the estimate of the thickness of the Lauren-
tian rocks was a sign of the accumulation in marine areas of
sediments of that thickness, it certainly seemed strange to any one
who believed in evolution that no clear and undisputed evidence of
the life of the era had been discovered anywhere. It seemed
difficult to conceive that the great marine areas of the time could
be devoid of life; for the teachings of Nature are clear enough in
showing that, where the circumstances are in any way suitable, life
in some form is sure to exist. There seems to be plenty of evidence
to show that the sea, in late pre-Cambrian times at least, could not
have varied materially in its temperature from that prevailing in
Cambrian time; therefore we are led to believe that there must have
been an abundance of life in the sea where there were no markedly
disturbing influences at work. Why, then, is it that after so many
years of diligent search we have still so poor a record of the life
of the era? I think that a careful examination of the materials of
which the pre-Cambrian rocks are composed, and of the contents
of the Cambrian conglomerates, tends to show that, up to the
present, we have not succeeded in meeting in any area with
sediments which give sure indications of having been deposited
under conditions fayourable to animal life. In the grits and
sandstones, both in svtw and when found as fragments in the con-
glomerates, there are indications of worm-tubes and tracks, as
in later rocks, But finer deposits and calcareous beds are so rare
that we are compelled to believe that we are almost everywhere
dealing with shore- and shallow-water deposits accumulating in
highly-disturbed areas subject to frequent volcanic outbursts.

This question has greatly interested me since the time when we
discovered that the pre-Cambrian rocks at St. David’s were mainly
of volcanic origin. When we first assumed that there was an
important series of rocks at St. David’s older than the basal
Cambrian conglomerates, we believed that they were mainly
ordinary sediments that had been greatly metamorphosed, fol-
lowing in this view tbe usual opinion held by petrologists and —
geologists at that time. In the year 1877, however, I commu-
nicated a paper to this Society in which evidence was given to show

1xx PROCEEDINGS OF THE GEOLOGICAL sociery. [May 1897,

that the majority of the pre-Cambrian rocks at St. David’s were
of volcanic origin; and petrological notes in confirmation of this
view were added by Mr. T. Davies, Prof. Bonney, and Prof. Judd.
In working out these conclusions I was also greatly assisted by
Prof. Hughes, Mr. Hudleston, and the late Mr. Tawney. Up to
this time the oldest volcanic rocks anywhere found in Britain were
supposed to be of Lower Silurian age; and Sir A. Ramsay, in his
Presidential Address to the British Association in 1880, so far frem
even then accepting our views, stated that ‘the oldest volcanic
products’ of which he had any personal knowledge were of
‘ Lower Silurian age.’ (Swansea Meeting, p. 7.)

Since that time, in several areas in Britain, it has been shown
that the pre-Cambrian rocks are mainly made up of igneous
materials, and even the so-called Laurentian rocks of the North-
west Highlands of Scotland are now known to contain but few beds
which can in any way be claimed as having had a sedimentary
origin, as explained in the following quotation from Sir A. Geikie’s
Address delivered before this Society in the year 1891 :—

‘With the possible exception of a strip of ground in the Gairloch
district—which includes graphite-schist, garnetiferous mica-schist,
limestone, and a few other remarkable rocks—no portion of the
fundamental gneiss has anywhere yielded a trace of materials that
can be supposed to be of sedimentary origin. Everywhere the rock
is thoroughly crystalline, and presents no structure that in any way
suggests an alteration of clastic constituents. Here and there
it can be traced into bands and bosses which, being either non-
foliated or foliated only in a slight degree, present the ordinary
characters of true eruptive masses. In Sutherland and Ross-shire
these amorphous patches occur abundantly. Their external margins
are not well defined, and they pass insensibly into the ordinary
gneiss, the dark basic massive rocks shading off into the coarse
basic gneisses, and the pegmatites of quartz and felspar which
traverse them merging into bands of grey quartzose gneiss.

‘So far, therefore, as present knowledge goes, the Lewisian gneiss
of the North-west Highlands of Scotland was originally a mass of
various eruptive rocks. It has subsequently undergone a succession
of deformations from enormous stresses within the terrestrial crust,
which have been investigated with great care by my colleagues
of the Geological Survey.’ *

1 Quart. Journ. Geol. Soc. vol. xlvii. Proc. 68.

Vol, 53.| ANNIVERSARY ADDRES3 OF THE PRESIDENT. lxxi

The pre-Cambrian Era,

Since, therefore, the rocks of pre-Cambrian age which are exposed
to view are either of igneous origin or so much changed that their
origin is doubtful, it seemed to me that valuable evidence bearing on
the pre-Cambrian era might be obtained by tabulating with care
all the fragments of rocks which had been found in the Cambrian
conglomerates in the several areas; and in the year 1890 I read a
paper at the meeting of the British Association, giving the results
which I had obtained up to that time. In each area it was found
that fragments derived from igneous rocks occurred in considerable
abundance, and it was clear that intrusive rocks of acid and
basic character, lavas, and volcanic tuffs were near at hand when the
Cambrian conglomerates were deposited. Quartzites and grits, such
as would be derived from the destruction of granitic rocks, were also
found to be abundant; but the hornstones and porcellanites, which
are mainly made up of fine volcanic dust, occur very frequently in
some areas, while clay-slates and calcareous fragments were com-
paratively rare—showing, as I have already stated, that in these
pre-Cambrian areas we can hardly expect to meet with rocks which
could have been deposited under conditions favourable to life.

It may now be useful to give short descriptions of the pre-
Cambrian rocks found in the different areas in Britain, with lists of
the fragments which have been obtained from the Cambrian con-
glomerates which repose upon them, or which are found in their
immediate neighbourhood; for, in addition to the testimony which
they furnish regarding the nature of the rocks of the pre-Cambrian
era, it will be seen in a very marked manner how little change
has taken place in them since the commencement of Cambrian
time, when the fragments were broken off.

Pembrokeshire.

I have already referred to the fact that it was in this county that
we first obtained clear evidence of pre-Cambrian volcanic rocks,
and it is here perhaps that most care has been taken in defining
the fragments obtained from the Cambrian conglomerates. In
the slides of rocks near St. David’s submitted by me in 1884 to
Mr. T. Davies he detected pebbles of a granite consisting of dirty
quartz with two felspars, quartz both dirty and clear and individual
felspars both orthoclase and plagioclase, pebbles of felsite, quartz-
felsite, quartz-schist, quartzite, basic igneous rocks, porcellanite,
and mica much altered. In referring to the fragments of granite

VOL. LIII. ft

xxii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1897,

he says :—‘ The view that the Cambrian conglomerate at St. David’s
encloses much waterworn débris of the Dimetian [7. e. the granite
of St. David’s] is, I think, fully justified by the evidence now
adduced from the examination of many slides of this rock, few of
which have failed to afford evidence of the presence, not only of
pebbles of a rock which under the microscope could not be dis-
tinguished from it, but also of its individual mineral constituents.
The slides examined and described here are not selected ones, but
have been taken as they were cut.’?

In 1886 Prof. Bonney kindly examined many slides submitted
by me to him, prepared from Cambrian conglomerates obtained
from different areas in Pembrokeshire, and at p. 362, Quart. Journ.
Geol. Soc. vol. xli. he says :—

‘A. When the Chanter’s Seat conglomerate was formed the
following rocks were undergoing denudation :—

‘(1) Granitoid rocks, identical with the existing Dimetian.

‘(2) Trachytic rocks, among which were probably true lava-
flows.

‘(8) Quartzites and schists, the latter resembling those which in
many districts occur rather high in the Archean series,

“(4) Ordinary sedimentary rocks.

‘Hence there was in this district a series of rocks, some much
older than others, which contributed to the formation of the
Cambrian conglomerate.

‘B. The conglomerate above the Trefgarn series is formed from
rocks which occur in the latter.

‘C. The peculiar characteristics distinctive of certain members
of the Trefgarn series had been assumed by them when the con-
glomerate was formed.

‘ D. Either the Dimetian is a member of an old gneissoid series
or, if itis the core of a volcanic group from which the trachytic
lavas had been ejected, this had been laid bare by denudation before
the Cambrian conglomerate was formed. Hence in either case both
the Dimetian and the felstones are pre-Cambrian.’

These notes by Mr. T. Davies and Prof. Bonney enable us to
realize with fair accuracy what rocks composed the pre-Cambrian
land in Pembrokeshire when the oldest of the Cambrian rocks in
that area were deposited. Of course it is possible that there were
other rocks in the area than those hitherto found as fragments in
the conglomerates, but we have in these lists all such as would

, * Quart. Journ. Geol. Soc. vol. xl. (1884) p. 555.

Vol. 53.] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxill

be doubtless fairly representative of the majority. Moreover, an
examination of the pre-Cambrian rocks which are now found
exposed tends strongly to the same conclusion. There was in
Pembrokeshire a typical volcanic group which had undergone a
considerable amount of structural change in pre-Cambrian times,
and before any of the fragments in the Cambrian conglomerates had
been broken off. Crushings and cleavage had produced brecciated
and schistose structures, and along many fractured lines intrusions
of basic and acid rocks had taken place. There seems to be evidence
also that the volcanic outbursts broke through a floor mainly com-
posed of granitic rocks associated probably with crystalline schists,
for in the lowest of the agglomerates fragments of such rocks occur
in association with pieces of lava showing definite flow-structure,
which appear as if they had been torn off during the explosions.
Though basic and acid fragments occur in the lowest agglomerates,
the latter certainly are greatly in excess, and the immediately
succeeding flows and breccias are mainly of an acid character.
Higher in the series the basic rocks predominate, but there again
‘some acid flows are intercalated with them. The more acid rocks
therefore are, as I formerly suggested, if we take them as a whole,
the oldest igneous rocks in Pembrokeshire. The oldest sediments
also, the porcellanites, occur in association with these lavas and
breccias, and they are clearly made up of stratified volcanic dust of
an acid character.

Higher up there are slaty and schistose beds which are largely
composed of basic dust. The slates are purplish and greenish, and
it is in these that I found traces of worm-tubes and tracks. They
occur in narrow bands interstratified with ashes and breccias. I
have hitherto searched them in vain for traces of other fossils, and
it seems to me that the conditions under which they must have been
deposited were very unfavourable to the existence of organisms
other than burrowing forms. The break between the Cambrian
and the pre-Cambrian in Pembrokeshire is a most important one,
and, in my opinion, there can be no doubt that a great lapse of
time took place between the deposition of the highest of the pre-
Cambrian beds and the lowest of the Cambrian.

The pre-Cambrian rocks had been raised to form dry land, had
suffered from the effects of great earth-movements with accom-
panying structural changes in the rocks, had been exposed to sub-
aerial influences, including probably that of ice-action, which assisted
the process of disintegration, and had been scored by valleys and

f2

xxiv PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1897

channels before the Lowest Cambrian conglomerates had been
deposited." There must have been also an enormous amount of loose
material on the land to yield the great thickness of Cambrian rocks
which accumulated as the shore was being depressed. The petro-
logical descriptions given by Mr. Davies, in the Quarterly Journal
of this Society, of the volcanic group (Pebidian) as it occurs in
Pembrokeshire were at the time unusually important, for until
then no one had suggested that lava-flows and other volcanic rocks
of so great an age occurred anywhere in Britain, and in his remarks.
on the fragments of rhyolite in the agglomerates he says, p. 166,,
vol. xxxiv. (1878) :—‘... the whole structure of the rock, in the
fluidal arrangement of the spherules, etc., is so like that of a rhyolite
that it is difficult to believe that we have not before us one at least.
of the many interesting varieties afforded by this group. One may
say with Zirkel, it is a rhyolite petrographically but not geologically.”
He also calls especial attention, at p. 164, to the difference between
the incipient spherulitic arrangement in the quartz-porphyries con-
taining the bipyramidal quartz, which occur as dykes in the granitoid
rocks and in the Pebidian, and the spherulitic structure of the
rhyolites. He says that the latter often ‘ weathers cream-white, the:
spherulitic structure when present being then perfectly exhibited
on the surface. On freshly-fractured surfaces, however, it is not
to be detected, even with the aid of a lens, and the very large
spherules, so prominent in the weathered specimens, present but:
faint indications of their presence. Seen in thin sections under
the microscope, however, the structure is at once recognizable, the:
whole mass appearing to consist of spherules, frequently arranged’ —
in well-marked bands of varying dimensions, and also confusedly
grouped without any apparent arrangement.’

The dykes of quartz-porphyry which cut through the granitoid’
rocks and the Lower beds of the Pebidian, but which never have:
been seen to penetrate the Cambrian rocks, are also interesting.
They are evidently of pre-Cambrian age, and have yielded frag-
ments to the Cambrian conglomerates. Prof. Judd, who was the
first to describe specimens of these rocks for me in the year
1877, says:—‘ The rock presents the most remarkable identity of
character with the gold-bearing quartz-porphyrite of Ostatye, near
Vordspatak, in Transylvania, which is an eruptive rock of Neogene
age. It is probably the oldest quartz-porphyrite yet noticed.’ *

1 See Hicks, ‘Pre-Cambrian Volcanoes and Glaciers,’ Geol. Mag. 1880,.
p: 488.
2 Quart. Journ. Geol. Soc. vol. xxxiii. p, 236.

Vol. 53.] ANNIVERSARY ADDRESS OF THE PRESIDENT, lxxy

Were it possible to obtain evidence of the forms of life which
existed when the earlier pre-Cambrian rocks were deposited, it
is probable that they would differ materially from those which
appeared on the scene when the Cambrian seas encroached upon
this land. In time we shall doubtless meet with better evidence
of the faunas of the pre-Cambrian seas than we have hitherto
obtained ; but I fear that it must be from areas which were less
subject to volcanic and other disturbances in pre-Cambrian times
-than these Pembrokeshire districts.

Caernarvonshire.

At the same meeting of the Society (Dec. 5th, 1877) as that at
which the volcanic rocks of pre-Cambrian age in Pembrokeshire
were described by me, I communicated a paper on some pre-Cambrian
rocks in Caernaryonshire which had been examined by Prof. Hughes,
Mr. Hudleston, Mr. Homfray, and myself in the previous summer.
As in the St. David’s paper, I was indebted to Mr. T. Davies for
very valuable petrological notes. Prof. Hughes also, in a separate
paper, gave a description of the pre-Cambrian rocks near Bangor
and Caernarvon which was accompanied by petrological notes from
Prof. Bonney. In these papers it was shown that the majority of
the pre-Cambrian rocks of that area were either granitoid rocks,
quartz-felsites, or other rocks of igneous origin, and that the Cam-
brian conglomerates which rested upon them were mainly derived
from such rocks, At p. 151 I stated that in the ‘great area of
pre-Cambrian rocks extending through the heart of Caernarvonshire
from below Tal-y-sarn on the south to St. Anne’s Chapel near
Bethesda on the north, along with another area near Caernarvon
and Bangor described by Prof. Hughes, are undoubtedly portions
still remaining of the old pre-Cambrian land; and in them, I
believe, are to be recognized representatives of the two great
unconformable series, Dimetian and Pebidian, so well shown at
St. David’s. With the former of these I would associate the so-called
syenitic ridge (granitoid rock) at Caernarvon; and with the latter
the altered beds* which rest directly on the syenitic ridge towards
Bangor, and the series chiefly described in this paper to the south
and north of Llyn Padarn and Moel Tryfaen. The prevailing
characters in this last series indicate the metamorphism of a pre-
Cambrian volcanic group of ashes and breccias rather than of true
sedimentary beds, the result of denudation and alteration only.’

? Quart. Journ. Geol. Soc. vol. xxxiv. (1878) p. 137.
? Now considered to be mainly devitrified rhyolites.

Ixxvi PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

_ Prof. Hughes, in speaking of the voleanic rocks near Bangor,
says (op. cit., p. 141):—‘ This series can be matched almost bed for
bed among the green slates and porphyries of the Lake District, and,
like these, may be referred to an original volcanic origin and some
subsequent metamorphism ; but they do not present a sequence like
the lowest part of the Cambrian, among which we find no beds that
could by any process be changed into the alternating agglomerates
and ashes of the Bangor volcanic series.’ In conclusion he says
(p. 144):—‘On the whole, then, it seems that we have an old*
volcanic series of remarkably persistent character in North and South
Wales (and probably we shall find, beyond the borders, that sub-
divisions can be made out in it, though as yet no break has been
proved in the series), and that the base of the Cambrian consists of
a strong conglomerate and grit, between which and the underlying
series there is great probability of an unconformity.’

In his important paper (Quart. Journ. Geol. Soc. vol. xxxy. 1879)
Prof. Bonney, after pointing out that the quartz-felsites of Llyn
Padarn and Bangor exhibited every indication of an igneous origin,
says (p. 319), ‘We must then refuse to these Caernarvonshire:
porphyries an origin different from that of other igneous rocks of
similar composition, and cease to quote them as examples of what
extreme metamorphism can effect,’ and ‘there is no difference of
any importance, so far as I can see, between these quartz-felsites and
comparatively modern rhyolites ; and if I could prove that a base still
remained undeyitrified I would give them the latter name. That
they were rhyolites in pre-Cambrian times I have no doubt.’ Some
geologists have since then endeavoured to show that these rocks are
of Cambrian instead of pre-Cambrian age ; but the further evidence
brought forward in papers by Prof. Bonney and Miss Raisin shows,
I think, conclusively that they form a part of the pre-Cambrian
volcanic series in Caernarvonshire, as first suggested by Prof. Hughes
and myself. | :

In the year 1878, accompanied by Prof. Torell, Mr. Tawney,
Prof. M°K. Hughes, and Dr. Sterry Hunt, I examined several other
areas in Caernarvonshire, and the results were communicated to the
Geological Society on Feb. 5th, 1879, an appendix on the micro-
scopic structure of some of the rocks being added by Prof. Bonney..
Of many of the rocks there referred to we spoke with some caution,
and I must admit that some of these have since been shown to
be of later date, while others are still of doubtful age; but those
referred to as occurring in the neighbourhood of Glynllifon and

Vol. 53. | ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxvli

Craig-y-dinas, and described as breccias and felspathic schistose
rocks, ete., are undoubtedly of pre-Cambrian age, as are also the
majority of the schistose rocks in the Lleyn Promontory.’

As illustrating the general conclusions arrived at by us at that
time, I will venture to quote the following remarks which occur in
the paper above referred to (Quart. Journ. Geol. Soc. vol. xxxv.
p. 300) :—‘ This condition of faulting along one side of these old
rocks, with the entire loss of the succeeding groups, is such a
frequent occurrence that it seems necessary to refer specially to the
physical conditions or probable causes which produced this effect.
One thing which has become particularly evident during our re-
searches is the fact that all bits of pre-Cambrian rocks which have
been included in succeeding sediments must have been not only in
an indurated condition when broken off from the parent rocks, but,
moreover, that they had even then undergone metamorphism, and
the more slaty ones a species of cleavage. The lowest Cambrian
rocks found are made up of bits and pebbles of these rocks, and so
like are they frequently to the solid rocks below that there can be
no doubt that they were the beach-pebbles when those old rocks
formed coast-lines. Now these old rocks must have undergone
gradual depression to receive the subsequent sediments ; and as
this depression could not take place in rigid or metamorphosed
rocks without producing fractures, we have at once one cause for
some of the faults, and reasons for coast-lines continuing for a
considerable period in some cases, whilst the surrounding areas
were becoming depressed to a great depth. The greatest faults,
however, and those which we have most frequently to deal with,
are those which occurred after the succeeding Cambrian and Silurian
sediments were deposited. During the great contractions of the
crust in Paleozoic time, especially towards its close, the rigid pre-
Cambrian crust could not fold, enormous fractures would take place
instead, and the overlying rocks would be thrown down. In some
cases, as found here and at other places, the pre-Cambrian would
be brought to the surface along one edge of the fracture, and its
other edge would be depressed to a great depth. The fault in
Ramsey Island, at St. David’s, has a downthrow of over 16,000 feet,
and I think the one here can hardly be less—that is, if the usual
sediments found in other areas in Caernarvonshire were ever
deposited here, and there seems no reason to suppose that they
were not.

1 See Miss Raisin’s paper, Quart. Journ. Geol. Soc. vol. xlix. (1893) pp. 160, 163.

Ixxviii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1807,

‘ According to this view beds belonging to many different horizons
in geological succession would now appear on the surface faulted
against the pre-Cambrian rocks ; and this it is that occurs wherever
they can be examined. I have found beds occupying every position
from the lowest Cambrian to the Bala Beds in direct contact with the
pre-Cambrian rocks as the result of faults. The constant recognition
of these facts has been of great value in attempting to unravel so
difficult a region as the Lleyn Promontory has proved to be.’

That the pre-Cambrian rocks had been greatly affected by lateral
or thrust-movements before the Cambrian rocks were deposited is
certain, and most of the schistosity and cleavage in them had been
- produced at that early time. Before I pass from the consideration
of the basal Cambrian rocks in Caernarvonshire, where they are
found in contact with or overlying the pre-Cambrian, especially where
this is of igneous origin, I may once more call attention to some of
the difficulties with which earlier observers had to contend when
attempting to define the exact boundary-lines between the formations
in greatly-disturbed areas. The crushings and crumplings due to
earth-movements, sometimes aided by faults, produced an appear-
ance of conformity, whilst in other cases the results were such that
experienced observers had been led to look upon the broken and
irregular junctions as evidences of igneous intrusions. Here,
usually, the illusion had been strengthened by the fact that in the
case of many of the pre-Cambrian rocks, especially the granites,
much decomposition had taken place in them, mainly by atmospheric
agencies, before the overlying rocks had been deposited, and the
arkose derived from the granite had been at first re-arranged by
water with but little additional matter.

I particularly called attention to some of these causes in my first
paper on the Caernarvonshire rocks in 1877, as may be seen from
the following passage :—‘ The supposed intrusive nature of these
ribs, and the apparent passage by gradual alteration mentioned by
various observers, are mainly due to the fact that the matrix in the
conglomerates has been derived from rocks immediately below or
from similar ones, and from a slight subsequent change in the
matrix, due, probably, to proximity to the intrusive dykes, aided by
a readiness perhaps in the material to assume this change. This is
clearly observed by watching the weathering of these conglomerates
even when in direct contact with the porphyritic series; for any
apparent melting-away of the hard pebble is shown not to be a
fact, since on very slight weathering the pebble becomes easily
separable from the matrix, and its outline is as perfect as on the day

Vol. 53.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxix

it became cemented in the mass, This appearance as if of a gradual
passage from conglomerates to rocks below, and from which most of
their materials must have been derived, has often presented itself to
my mind in examining these basal lines of the pre-Cambrian rocks.’ *

In Caernarvonshire, Upper, Middle, and traces of Lower Cambrian
fossils have been discovered, the latter mainly at the Penrhyn slate-
quarry, near Bethesda, It is unfortunate that these have not as
yet been fully worked out, but that there are zones of fossils below
the beds containing Conocoryphe Viola described by Dr. Woodward
seemed to me, when I last examined the section, quite clear. The
sections of Cambrian rocks in this area agree remarkably with those
found in Pembrokeshire, and I have no doubt that the underlying
Cambrian conglomerates rest here also on an eroded surface of
pre-Cambrian rocks.

Anglesey.

Until the year 1878 it was not suspected that the granite and
gneiss-rocks in Central Anglesey were of pre-Cambrian age, but in
that year, after visiting the area, I read a paper at the British Associ-
ation in which I claimed the so-called intrusive granite in Central
Anglesey and the associated gneiss, as well as the whole of the area
marked as altered Cambrian in that island, as of pre-Cambrian age.
I stated that the granitoid and gneissose rocks were at the base, and
that, as at St. David’s, they were succeeded by the agglomerates,
breccias, greenstone-bands, and schists of the Pebidian group. In
the Memoirs of the Geological Survey published in 1881, the view that
the granite was intrusive in Cambrian and Silurian rocks, and
that the latter had been metamorphosed into gneiss, schists, etc., was
still upheld. The pre-Cambrian rocks of Anglesey have since been
described by Prof. Hughes, Prof. Bonney, Dr. Callaway, Mr. Blake,
and others, and it is now fully admitted that the views which
we advanced in 1878 are in the main correct. In his Address to
this Society in 1891, Sir A. Geikie says:—‘ Let me frankly say
at once that in denying the existence of pre-Cambrian rocks in
Anglesey, and in endeavouring to account for all the schists by the
metamorphism of Cambrian and Silurian strata, my predecessor
was, In my opinion, mistaken’?; and again: ‘There is un-
doubtedly in Central Anglesey a core of gneiss which, if petro-
graphical characters may be taken as a guide, must certainly be
looked upon as Archean.’ Here he refers to the so-called axis

* Quart. Journ. Geol. Soc. vol. xxxiv. (1878) p. 151.
? Ibid. vol. xlvii. (1891) Proc. pp. 82, 83.

domo.” PROCEEDINGS OF THE GEOLOGICAL society. « [May 1897,

which I classed as Dimetian in 1878, and afterwards often men-
tioned as resembling the granitoid and massive gneissose rocks in
the North-west of Scotland. In the Cambrian conglomerates near
Llanfaelog there is a remarkable assemblage of fragments which
gives indisputable evidence of the pre-Cambrian rocks which were
in existence in that area when the conglomerates were deposited,
and of their condition when the fragments were broken off.

In papers read before the Society in 1883, the fragments con-
tained in these conglomerates were described by Prof. Bonney and
myself, and we then showed that large masses of the granite,
gneiss, volcanic rocks, and schists, such as are now seen in situ in
the neighbourhood, are abundant in them, and by microscopic
examination it was found that no important change had taken place
in these rocks since pre-Cambrian time. Hitherto no remains of
organisms have been obtained from undoubted pre-Cambrian rocks
in Anglesey, but recently Mr. Greenly (Quart. Journ. Geol. Soc.
vol. lii. 1896, p. 618) has referred to some sponge-spicules which
he found in a grit near Beaumaris as possibly of pre-Cambrian
age. Upper Cambrian fossils were found by Prof. Hughes many
years ago in rocks near the centre of the island, which until then
had been classed as of Caradoc age (Quart. Journ. Geol. Soc.
vol. xxxvi. 1880, p. 237).

Up to the present, Middle and Lower Cambrian fossils have not
been discovered there, but I see no reason whatever why the flagey
sandstones which directly overlie the conglomerates near Llanfaelog
and along the western border of the granite-and-gneiss axis should
not yield Lower or Middle Cambrian fossils if properly searched, as:
they clearly are much older than the rocks containing the Upper
Cambrian fossils farther north.

Merionethshire.

On the flanks of the Harlech Mountains Upper and Middle
Cambrian fossils were found many years ago—the latter soon after
we described the Menevian beds at St. David’s. As there are
in the Harlech Mountains considerable thicknesses of sediments
underlying the beds containing the Menevian fossils, it is more than
likely that there are zones also, which only require to be worked
out, which would probably contain fossils representing the Solva and
Caerfai groups of St. David’s, as the lithological characters of the
underlying beds are remarkably like those at St. David’s.

I have expressed the opinion in previous papers that there are
indications of a core of pre-Cambrian rocks in these mountains,

Vol. 53.] ANNIVERSARY ADDRESS OF THE PRESIDANT. lxxxi

and have pointed out spots where there appear to be traces of an un-
conformity between typical Harlech rocks and some underlying beds.

Western and Central England.

In the years 1864 and 1865 Dr. Holl read papers before this
Society in which he maintained that the rocks forming the axis of
the Malvern Hills, then classed as syenite, were not intrusive in
the Cambrian and Silurian rocks, but were a portion of an old
pre-Cambrian land on which the newer rocks had been deposited.
In the first-named year Mr. Salter and I announced (Brit. Assoc.,
Bath Meeting) that the so-called syenite of St. David’s was also
of pre-Cambrian age, and that it supported, but did not penetrate,
the shallow-water accumulations of the surrounding Cambrian.
These -views were strongly controverted at the time, and in
speaking of the Malvern rocks Sir R. Murchison in 1867 (‘ Siluria,’
4th ed. p. 93) said:—‘I consider them to be a metamorphosed
mass of the lower portion of the Cambrian deposits, and therefore
equivalents of the crystalline (metamorphic) Cambrian rock of
Anglesey and North Wales.’ As is well known, the view here
expressed by Sir R. Murchison was the one held by the chiefs of
the Geological Survey in regard to the pre-Cambrian crystalline
masses in Wales up to a very recent period.

Though the crystalline nucleus of the Malvern Hills was shown
by Dr. Holl to be of pre-Cambrian age, it was not until the
year 1879 that it was pointed out, chiefly through the labours of
Dr. Callaway, that there was a newer group of pre-Cambrian rocks
in the spurs running off from the eastern side of the Herefordshire
Beacon, which he then correlated with the Pebidian group of
St. David’s. In that year I visited the district with Dr. Callaway,
and was struck by the similarity of the rocks occurring there
with those which we had previously described at St. David’s
and in North Wales. Though typical Lower and Middle Cam-
brian fossils have not as yet been discovered on the flanks
of the Malvern chain, it is more than probable that rocks of
that age occur in the area. Upper Cambrian fossils, as is well
known, were discovered there in beds overlying the Hollybush
Sandstone many years ago. In the year 1877 Mr.S. Allport? made
the important announcement that the Wrekin ridge and another area
to the north-west, coloured as intrusive greenstone in the Geological
Survey maps, consisted almost entirely of a ‘series of ancient

1 See Proc. Geol. Assoc. for 1879, vol. vi. p. 233.
? Quart. Journ. Geol. Soc. vol. xxxiii. p. 449.

Ixxxi PROCEEDINGS OF THE GEOLOGICAL SOCIETY, [May 1897,

vitreous and semivitreous lavas, with their associated agglomerates
and ashes.’ He did not, however, recognize that they were of pre-
Cambrian age, but supposed them to belong to the ‘ older contempor-
aneous volcanic series so extensively developed in the Lower Silurian
district of Salop and Radnor.’

In the same year Dr. Callaway published a paper in the Journal
of this Society, vol. xxxilil. p. 652, in which he gave an account of
the discovery by him some years before of Upper Cambrian fossils in
the Shineton Shales which had previously been classed as of Caradoc
age. He also mentioned the occurrence of underlying rocks which
he correlated with the Hollybush Sandstone near Malvern.

As the result of these discoveries he was led soon afterwards to
class the igneous rocks of the Wrekin and of neighbouring areas as
of pre-Cambrian age.

On June 11th, 1879,‘ a paper on the pre-Cambrian rocks of
Shropshire was read by Dr. Callaway before the Geological Society
in which he grouped them geographically as follows :—

‘A. The Wrekin Growp.—Lilleshall Hill, Ercal, Lawrence Hill,
the Wrekin, Primrose Hill.

‘B. Caer Caradoc Group.—The Lawley, Caer Caradoc, the
Ragleth, Hope Bowdler Hill.

‘C. Horderley Group.

‘D. Kington Group.’

He claimed that the granitoid rocks, as at Malvern and St. David’s,
* were the oldest, and that they were overlain by the Volcanic Group.

In his ‘ Notes on the Microscopic Structure of some Shropshire
Rocks,’ read at the same meeting, Prof. Bonney says, p. 668 :—‘ As
the result of the investigations above described, I should conclude,
from microscopic evidence alone, irrespective of that obtained in the
field, that the granitoid series was much older than the other rocks,
and that materials from it, together with fragments from the rhyo-
litic series, had been worked up into several of the later clastic rocks.’

Subsequently Dr. Callaway added fresh areas to those he had
previously described, and lastly included the Longmynd rocks
(Cambrian of Murchison) in the pre-Cambrian under the term
Longmyndian. It is difficult at present to say whether all or only
a part of the Longmynd rocks, as suggested by Mr. Blake, are of
pre-Cambrian age, and it is most unfortunate that up to the
present no important additions to the fauna of these rocks has been
made since the discovery in them by Mr. Salter of a fragment of a
trilobite (Paleopyge Ramsay?) and annelid-borings.

1 Quart. Journ. Geol. Soc. vol. xxxv. p. 643,

Vol. 53.] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxxili

These rocks are well stratified, but must have been deposited in
shallow water, the materials being derived mainly from volcanic
rocks, or possibly, in part, as dust and muds, directly from volcanoes.

The age of the volcanic rocks, now the Uriconian of Dr. Callaway
(originally classed by him with the Pebidian of St. David’s, which
they greatly resemble), has been proved beyond doubt by the very
important discoveries made by Dr. Callaway, Prof. Lapworth,’
and Mr. 8. Groom of Lower and Middle Cambrian fossils in
the Comley Sandstone (originally called Hollybush Sandstone
by Dr. Callaway) near Lilleshall Hill. This sandstone rests on a
quartzite, and the latter lies unconformably on the volcanic rocks
of Little Caradoc.

In the year 1882 Prof. Lapworth announced the discovery of
Cambrian Rocks in the neighbourhood of Birmingham (Geol.
Mag. 1882, p. 563). These rocks had previously been classed as of
much newer age, not in any case older than Upper Silurian. The
discovery appears to have been jointly made by Prof. Lapworth,
Mr. T.S. Houghton, and Mr. W. J. Harrison. Several exposures are
referred to, namely, the Lower Lickey Ridge, Nuneaton, Stocking-
ford, and Dort Hill. In the shales of Stockingford Prof. Lapworth
discovered many typical Upper Cambrian fossils.” The investigations
showed ‘that a range of country 10 or 12 miles in length by
2 miles in width is occupied by rocks of Upper Cambrian age.’
There are two main divisions, the lower being a thickly bedded
quartzite which at its base is a ‘coarse breccia made up of
fragments of red and green felspathic rocks, slaty shales, and
yarious quartz-porphyries’; these ‘have apparently been derived
from an older series of igneous and altered strata’ which may
occasionally be seen rising out from below them. The rocks of
Charnwood Forest in Leicestershire, which were formerly supposed
to be of Cambrian age, have in recent years been most carefully
described by the Rev. E. Hill and Prof. Bonney, who have shown
that they resemble much more closely the volcanic rocks of pre-
Cambrian age than any which have been classed elsewhere on
satisfactory evidence as Cambrian. Though there are no beds
containing Cambrian fossils reposing upon these rocks, it is worthy
of note that the fossiliferous Upper Cambrian in the neighbouring
area of Nuneaton previously mentioned rests on some volcanic rocks,
which greatly resemble in their condition some of the Charnwood

1 Geol. Mag. 1888, p. 484; tid. 1891, p. 529.

2 More recently Prof. Lapworth discovered fossils in the quartzite series
which are very probably of Lower Cambrian age.

Ixxxiv PROCEEDINGS OF THE GEOLOGICAL socreTy. [May 1897,

series. It seems to me that there is strong evidence to show that
the Charnwood Forest rocks are of pre-Cambrian age, and this
is the view generally adopted by the majority of those who have
‘been working among the older rocks.

The pre-Cambrian rocks in various areas in England and Wales
to which I have referred have been defined as such only within
comparatively recent years, the first announcements having been
made in 1864, when Dr. Holl referred to the crystalline axis of the
Malvern Hills as older than the surrounding rocks, in a paper read
before the Society in June of that year ‘On the Geological Structure
of the Malvern Hills and Adjacent District;’ and Mr.. Salter, at
the meeting of the British Association of the same year, gave an
account of our discovery of a ‘ Pre-Cambrian Island at St. David’s,
Pembrokeshire.’

Before the year 1862, when Mr. Salter discovered Paradowides
in the Lower Lingula-Flags of St. David’s, the only fossils that
had been obtained from the Lower or Middle Cambrian rocks in
England or Wales were the fragment of trilobite and the traces of
annelids, already referred to, from the Longmynd rocks; and it is
since then that all the other fossils which are now known to mark
so many zones in the Middle and Lower Cambrian of Britain have
been discovered, and the life-history of those periods made out.

Scotland.

In the year 1878 I read a paper before the Society which re-
opened the controversy concerning the so-called metamorphic rocks
of the Highlands, which had then been dormant for many years.
In that paper I maintained that the views held by Prof. Nicol
were more in accordance with the facts which I had obtained than
were those of Sir R. Murchison and the members of the Geological
Survey. Since that date numerous papers have been written on
these rocks, especially on those of the North-western Highlands,
and much new and important information concerning them and
the overlying rocks has been obtained. ‘The gradual and important
additions to our knowledge which have been made will be under-
stood by reference to the following papers :—Hicks, Quart. Journ.
Geol. Soc. vol. xxxiv. 1878; Hudleston, Proc. Geol. Assoc. 1879,
vol. vi.; Bonney, Q. J. G. 8. vol. xxxvi. 1880; Hicks & Davies, Geol.
Mag. 1880; Hicks, Proc. Geol. Assoc. 1880, vol. vi.; Hicks &
Bonney, Q. J. G. S. vol. xxxix. 1883; Callaway, Q. J. G. S.
vol. xxxvii. 1881, and vol. xxxix. 1883; Hudleston, Geol. Mag.
1882; Lapworth, Geol. Mag. 1883, and Proc. Geol. Assoc. 1884,
vol. viii.; Blake, ibid.; Geikie, Peach, & Horne, ‘ Nature,’ 1884 ;

Vol. 53. | ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxxv

Peach & Horne, Q. J. G.S. vol. xliv. 1888; and the Reports of
the Geological Survey.

In the papers by Mr. T. Davies, Prof. Bonney, Dr. Callaway, and
myself petrological descriptions of the characteristic rocks found in
the neighbourhoods of Gairloch, Loch Maree, Central and Southern
Ross-shire, and a portion of the Central Highlands were given.
Prof. Bonney showed that the so-called ‘syenite’ in Glen Logan
was not an intrusive mass, but a portion of the old gneiss
floor which had been brought into that position by faults, and I
pointed out that the older gneisses cropped up in several areas east
of Loch Maree, where previously they had been unsuspected, and
also that the schistose series in the neighbourhood of Gairloch was
unlike any which had previously been described from the western
areas. 1t was further shown that at the base of the Torridon
sandstone large masses of these schists occurred in association with
fragments derived from the so-called Lewisian gneiss and numerous
other fragments which could not then be located in the district.
Attention was also called to the highly-faulted condition of the
rocks in the several areas examined, and the newer rocks were
stated to occur in broken synclinal folds.

In the year 1883 Prof. Lapworth, when describing the Durness
and Eriboll areas, pointed to evidences in that area of an old moun-
tain system accompanied by great dislocations. | He“also divided
the Paleozoic rocks of those areas into numerous fossil zones.
Moreover, Dr. Callaway, in the same year, showed that there were
evidences of great dislocations and of foldings of the limestone- and
quartzite-beds, not only at Durness but also in the neighbourhood
of Assynt. He had previously, in a paper communicated to the
Geological Society in 1881, stated that he had arrived at the con-
clusion that the sections in those areas ‘ were broken, and therefore
untrustworthy, but that the relations of the several rock-groups
were inconsistent with the supposition that the limestone passed
pelow any part of the newer metamorphic series.’ *

In the year 1884 the Director-General of the Geological Survey
(Sir A. Geikie) and Messrs. Peach & Horne, in a paper in ‘ Nature,’
November 13th (vol. xxxi. p. 32), stated that the results recently
obtained by them when re-surveying the Durness and Eriboll areas
went to show that ‘the Silurian strata in the Durness area are
arranged in the form of a basin truncated on the east side by a
fault that brings them against the Archean gneiss.’ They also refer
to the flexures and great dislocations of the strata in the Eriboll
area, previously pointed out by Prof. Lapworth, and Sir A. Geikie

1 Quart. Journ. Geol. Soc. vol, xxxvii. p. 239,

Ixxxvi PROCEEDINGS OF THE GEOLOGICAL socreTy. [May 1897,.

concludes by saying: ‘ With every desire to follow the interpretation
of my late chief, I criticized minutely each detail of the work upon
the ground; but I found the evidence altogether overwhelming
against the upward succession which Murchison believed to exist
in Eriboll from the base of the Silurian strata into an upper
conformable series of schists and gneisses’ (p. 30). Since that time
the districts about Loch Maree, Gairloch, Auchnasheen, and Loch
Carron have been surveyed by the officers of the Geological Survey,
and in their report for 1895 (p. 19) it is stated that ‘in the area
mapped between Auchnasheen and Loch Alsh, evidence has been °
obtained of the alternations of strips of recognizable Lewisian Gneiss:
with schists of the true Moine type . . . Some of the cores and
lenticles of gneiss, almost certainly Lewisian, attain a considerable
size. Thus, to the south of Auchnasheen, a tract of hornblendic
gneiss covers an area of perhaps more than 50 square miles. It
is but right to state that Prof. Bonney and I called particular
attention to what we considered the re-appearance of the older
gneisses in these areas in 1883, and therefore far to the east of any
areas in which they had previously been described, and the following
passage occurs in my paper of 1883 :—‘ The presence of a group
of gneisses of so old-looking a character, and with a crystalline
condition, as shown in microscopical sections, not to be distin-
guished from the oldest gneisses of the Loch Maree type, reaching
to the crest of a mountain of over 2300 feet in height, in an area
regarded as containing the so-called newer Silurian metamorphic
rocks only, and east of the limestone series, is a fact of enormous
importance, especially as we are told by Murchison and Geikie that
the rocks found in this area are newer than the limestone
series of Loch Kishorn, and that they repose conformably upon the
latter.’? Since the rocks of these areas were described by us in
1883, views as to the origin of the gneisses and of some of the
crystalline schists have undergone a considerable change, and it is
now generally admitted that the massive gneisses are in the main
igneous rocks which had been crumpled, crushed, and deformed in
pre-Cambrian times. Facts bearing on these questions have been
worked out with great care by the officers of the Geological Survey
in several areas in Scotland.

At the Meeting of the British Association in 1891 an important
announcement was made by Sir A. Geikie of the discovery of Lower
Cambrian fossils by the officers of the Geological Survey in rocks.
overlying unconformably the Torridon Sandstone in the North-west
Highlands. The Torridon Sandstone, which attains a thickness:

2 Quart. Journ. Geol. Soc. vol. xxxix. p. 151.

Vol. 53. | ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxxvili

of several thousand feet in the neighbourhood of Loch Maree and
Loch Torridon in Ross-shire, was until then generally classed as of
Cambrian age; therefore this discovery of the Olenellus-zone in the
overlying rocks at once made it clear that the Torridon Sandstone
would in future have to be classed as of pre-Cambrian age. It had
been known for a long period that the Torridon Sandstone rested on
a strongly-eroded surface of Archean gneiss and schists, fragments
of which occurred in it, and in the year 1878 (Quart. Journ. Geol.
Soc. vol. xxxiv. p. 813) I particularly called attention to the fact that
in addition to these local fragments there were others, especially in
the basal breccias at Gairloch, which did not seem ‘to have come
from the immediate neighbourhood, but were ‘ similar in many
respects to those found in the Cambrian conglomerates in Wales,
and which were there undoubtedly derived from the underlying
Pebidian beds.’* In the more recent descriptions given by the
Geological Surveyors of the Torridon Sandstone in the different
areas attention is also pointedly called to these facts, and it
seems highly probable that at one time a volcanic group of rocks
similar to the Pebidian of Wales must have existed either in the
area or at no great distance from it. In that case the volcanic
group would have to be classed as older than the Torridonian and
newer than the gneiss and crystalline schists, as in Wales. The
Longmyndian and Tourridonian rocks seem therefore to be nearly on
the same horizon, and intermediate in position between the Pebidian
and the Cambrian. In referring to the Torridonian rocks in
the ‘ Annual Report of the Geological Survey’ for 1895, p. 20,
Sir A. Geikie says :—‘ During the progress of the mapping of the
Torridonian rocks in the west of Sutherland and Ross-shire, the
attention of the surveyors has been continually directed to the
nature of the sediments composing these rocks, and to the inter-
esting problems connected with their origin. While the sandstones,
shales, and conglomerates of this system may be reasonably supposed
to have been mainly derived from the denudation of the Lewisian
Gneiss, they yet contain materials which have not been found in
the gneiss itself, and the source of which it would be important, if
possible, to discover. The contents of the conglomerates seem to
prove the existence of some series of sedimentary and volcanic
rocks older than the Torridonian formations. It seemed desirable
that a detailed study should be made of the Torridonian petrography.

2 In 1880, Proc. Geol. Assoc., I mentioned the following as occurrirg as
fragments, namely, gneiss, granite, quartz-felsite, quartz-quartzite, jasper, taJcose,
chloritic and micaceous schistose rocks, etc. See also ‘ Pre-Cambrian Rovds in
Cambrian Conglomerates, Geol. Mag. 1890, p. 516.

vou. LI. g

lxxxviil PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

Accordingly I requested Mr. Teall to undertake this task. He
has already made considerable progress in the investigation,
directing special attention to those pebbles in the conglomerates
which were evidently not derived from the immediately underlying
gneiss. The specimens collected in the field and submitted to him
comprise vein-quartz, quartzites, cherts, jasper, felsites, quartz-
schists, and mica-schist, including green avanturine.’ And at
page 21 (Notes by Mr. Teall):—‘ The felsites are exceptionally
interesting, and have been described in detail. They are dark-
purplish compact rocks, usually less red in colour than the jaspers,
but not always easily distinguishable from them. They consist of
porphyritic crystals, and crystal-groups of felspar, often oligoclase,
in a spherulitic, micropegmatitic, micropoikilitic, or microcrystal-
line groundmass. The spherulitic felsites occasionally show traces
of perlitic structure in the matter which fills up the spaces between
the spherulites. These felsites bear the most striking resemblance
to those of Uriconian age which occur in Shropshire, and which
have furnished pebbles to some portions of the Longmyndian rocks,’
It is also stated that ‘the tracts of Torridonian rocks mapped last
year have lain entirely to the east of the line of great complication,
and are all moved masses.’ In my paper, Quart. Journ. Geol. Soc.
vol. xxxix, (1883), I called attention to the fact that we had found
these rocks in several localities east of the limit usually assigned to
them, including most of the areas referred to in the report, and
said, p. 148 :—‘ That these are true Torridon Sandstones, and not
subordinate bands in the quartzite series, is perfectly clear to any
one who has seen the succession on the Torridon shores.’

Recent researches by the Geological Surveyors and others have
_ tended strongly to confirm the view that the gneisses and crystal-
line schists in the central areas in Ross and Sutherland, as also in
the Central Highlands, are of pre-Cambrian age, but the exact age
of some newer rocks which overlie or are entangled amongst them
has not as yet been made out. It is probable that in time some of
these will be shown to be of Cambrian age.

South of England and Channel Islands.

Having thus referred to the areas in Wales, the centre of
England, and North Britain, where the facts are clear, it may now
be well to enquire into the evidence which has been brought
forward to show the presence of pre-Cambrian rocks in more
southerly districts. In my paper ‘On some Recent Researches .
among Pre-Cambrian Rocks in the British Isles’ (Proc. Geol.

Walk 534! ANNIVERSARY ADDRESS OF THE PRESIDENT. exo

Assoc. vol. vii. 1881, p. 73), I spoke with some doubt as to the
evidence then available to show the occurrence of pre-Cambrian
rocks in Cornwall, but said :—‘ At present, however, it would be
unsafe to theorize upon the eyidence available, but no harm can
arise from referring briefly to the facts. It is well known that the
Eddystone lighthouse is built upon rocks of a gneissose type, some
massive, others more schistose. These gneisses appear to be of the
true type of the older or granitoid kind, hence rendering it probable
that in the Channel, at least, a ridge of these older rocks occurs.’

Prof. Bonney, from the result of careful researches in the Lizard
district, has arrived at the conclusion that at any rate the gneisses,
hornblende-, and other schists may probably be of pre-Cambrian.
age, and the researches of Mr. J. H. Collins, Mr. Howard Fox, and
Mr. J. J. H. Teall have also shown that rocks of Ordovician age are
faulted against the gneissose rocks at several points in that district.
The finding of radiolarian cherts in these Ordovician rocks by
Messrse Fox & Teall is of interest as indicating that at least
moderately deep-water deposits were being thrown down in this
area early in Paleozoic time. In Quart. Journ. Geol. Soc. vol. xxxi.
1875, I published a map of the European area, showing the com-
parative thickness and depth of deposition of the Cambrian and
Lower Silurian rocks in different areas, and one of the lines of
greatest depression was shown to run in a direction from S.W. to
N.E. south of the English Channel. In that paper also I said that
the evidence seemed to show that moderately decp water covered
many of the western areas in Europe at that time. Prof. Bonney
has suggested that the micaceous and chloritic schists at Start Point
which are faulted against slaty rocks, probably of Devonian age,
are pre-Cambrian. These schists, he says, are almost identical
with some of the members of the great upper group of schists in
the Alps. Those who know the amount of faulting and crushing
which has taken place in the rocks of South Devon can readily
realize why, if these be pre-Cambrian rocks, there is no actual
evidence showing Lower Paleozoic rocks in contact with them.

The researches of the Rev. K. Hill, Prof. Bonney, Dr. Barrois,
M. Bigot, and Prof. de Lapparent in the Channel Islands and
neighbouring areas in Normandy and Britanny show clearly that
there both Upper and Lower Cambrian rocks repose unconformably
upon pre-Cambrian gneiss-rocks and felstones, the latter resembling
closely those which occur in the volcanic series of Wales and
Shropshire. I am told by Prof. Bonney that in Jersey felstones
and coarser crystalline igneous rocks underlie a conglomerate
accepted now as basal Cambrian, and some of the crystallines are

XC PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

older than the Schistes de St. L6. In Alderney granitic rocks
underlie Grés Felspathique. The crystallines of Guernsey and of
Sark cannot be dated, but it is reasonable to suppose that they
are of about the same age as those in the other islands, while the
hornblende-schists of Sark are precisely the same as those of the
Lizard, and there are moreover old-looking gneisses. The occurrence
of undoubted Cambrian rocks in the areas last referred to, and
unconformable to the volcanic and gneiss-rocks, shows clearly that
the physical changes which affected the British Isles also extended
over wide areas in Western Europe.

These discoveries, moreover, add confirmatory evidence in support
of the contention in my paper read before the Society in 1875,
p. 558, where I maintain that, wherever in the European areas
the rocks ‘ belonging to the old pre-Cambrian continent are now
found exposed, they show every indication of having been old
land-surfaces before the overlying rocks had been deposited, and
almost invariably the lowest beds in contact with them aré either
sandstones or conglomerates, whether they belong to the Cam-
brian or the Silurian.’ (Quart. Journ. Geol. Soc. vol. xxxi.)

Treland.

Though it is now fully admitted that pre-Cambrian rocks
occur in several areas in Ireland, some doubt still exists as to the
exact position of the rocks which have been classed as Cambrian in
that island. They are known to occur only at Howth, about Bray,
and in Wexford.

Mr. A. McHenry and Mr. W. W. Watts, in their ‘Guide to the
Collections of Rocks and Fossils belonging to the Geological Survey
of Ireland’ (1895), say that the only fossils hitherto obtained from
these rocks are Oldhamia, which is of ‘ doubtful but probably of
organic origin,’ and tracks and burrows of worms, and the micro-
scopic bodies from the slates of Howth, stated by Prof. Sollas ‘ to
have the appearance of being relics of minute animals (radiolaria).’

Prof. Sollas has also more recently described an obscure ‘ but
probably organic structure under the name Pucksia M¢Henryr’
froin these rocks. The strata are pierced by dykes of igneous rocks,
but ‘no contemporaneous volcanic rocks are known’ in them.

As it would occupy far more space than it would be reasonable
to ask you to grant me for this address, if I were to attempt
to review all the work which has been done among these rocks
during the past 30 or 35 years, I have thought it advisable to

a

Vol. 53.] ANNIVERSARY ADDRESS OF THE PRESIDENT. X¢l

confine my remarks, with one or two exceptions, to the researches
which have been carried on in the British Isles, and in areas with
which Iam more or less familiar. It will, of course, be understood
that important advances have also been made during the same time
in many other countries in Europe and in America; and, as bearing
on the biological history, the discoveries made by the Scandinavian,
Russian, and American geologists have been of the highest value.

Summary.

From the scattered details which I have thus imperfectly laid
before you, it may be well to sum up the main results which have
been obtained. It has been seen that very different views are now
held in regard to the origin of many of the pre-Cambrian rocks from
those which prevailed from 20 to 30 years ago. Then all the crys-
talline schists and gneisses, and many also of the granitic rocks, were
looked upon as metamorphosed sediments. Gradually, and mainly
owing to the careful microscopical work which has been carried on
by so many eminent petrologists in this and other countries, we have
been led to recognize that a very large proportion of the crystalline
rocks previously supposed to have been sediments are igneous
rocks which have been crushed, cleaved, and have suffered other
changes from chemical and mechanical influences, It has been
- shown also that very large and unexpected proportions of the pre-
Cambrian rocks were built up from materials derived from volcanic
outbursts, and that this was particularly the case in the British
areas. As a consequence, few of the sediments are such as could
have been deposited in marine areas favourable to organic life, or
such as would be likely to retain very definite evidence of its
existence. Still the very earliest of the Cambrian rocks, or those
sediments which were deposited in a fairly tranquil sea, following
the great physical changes which took place at the close of the
pre-Cambrian era, contain ample evidence that the sea which was
gradually encroaching on the pre-Cambrian land on both sides of
the Atlantic teemed with life, in which probably all the orders of
the Invertebrata were represented.

These discoveries have undoubtedly added most important
evidence in support of the theory of the gradual evolution of
organic life, and lead us to speak very hopefully of finding yet
earlier traces of the life-history of our globe. The readiness with
which suitable forms tenanted all the areas as they were covered
by the sea shows that there was abundance of life near at hand in
the adjoining submerged areas, and that the charges then taking

Xcil PROCEEDINGS OF THE GEOLOGICAL society. [May 1897,

place were only such as had been going on more or Jess continuously
on the surface of the globe from the moment when the waters
began to collect or, at any rate, became suitable for the existence of
life. The earliest records may have been completely blotted out by
the repeated changes which had previously taken place, or may
be entirely buried beneath and hidden from our view in the great
oceanic areas. Still the results obtained within comparatively
recent years lead us to hope that there is yet room to discover much
in those areas which hitherto have been but imperfectly examined
or not at all explored.

In conclusion, I may, I think, venture to say that as geologists
we feel quite certain that from the earliest Cambrian to the present
time, we are dealing only with a comparatively recent period in the
world’s history; and, as biologists, that we are convinced that
innumerable successions of organic beings must have lived and
passed away in the pre-Cambrian era before such an advance could
have been attained as is manifest in those forms which tenanted
the earliest Cambrian seas. We may also, I think, venture to
congratulate ourselves that recent researches have enabled geologists
to take up a far more satisfactory position in regard to the theory of
evolution than when Darwin felt constrained to pen the following
words in referring to the imperfection of the geological record
(‘Origin of Species,’ p. 310):—‘The several difficulties here discussed,
namely, our not finding in the successive formations infinitely
numerous transitional links between the many species which now
exist or have existed; the sudden manner in which whole groups
of species appear in our European formations; the almost entire
absence, as at present known, of fossiliferous formations beneath the
Silurian strata, are all undoubtedly of the gravest nature. We see
this in the plainest manner by the fact that all the most eminent
paleontologists, namely, Cuvier, Owen, Agassiz, Barrande, Falconer,
EK. Forbes, etc., and all our greatest geologists, as Lyell, Murchison,
Sedgwick, etc., have unanimously, often vehemently, maintained
the immutability of species.’

No one could now venture to blame our predecessors for the
cautious attitude which they assumed in consequence of the evidence
then available to them; but I think that we may take a lesson from
the results smce then obtained, and not be too ready to condemn
or cast a doubt on new discoveries which may not quite fit in with
our preconceived ideas.

Vols 53. | PROCEEDINGS OF THE GEOLOGICAL SOCIETY. x¢cill

February 24th, 1897.
Dr. Henry Hrioxs, F.R.S., President, in the Chair.

Capt. Arthur Richard Dwerryhouse, 65 Louis Street, Leeds;
Percy Emary, Hsq., 12 Alwyne Square, Canonbury, N.; William
Douglas Ferguson, Esg., 7 Great Winchester Street, E.C.;
Charles Olden, Esq., Whitby Lodge, St. George’s Terrace, Perth,
Western Australia; and George de Wolf, Esq., Vancouver, British
Columbia, were elected Fellows of the Society.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘On the Nature and Origin of the Rauenthal Serpentine.’
By Miss Catherine A. Raisin, B.Sc. (Communicated by Prof. T. G.
monney, Dasc., LE.D., F.R.S., V.P.G.8.)

2.*On Two Boulders of Granite from the Middle Chalk of
Betchworth (Surrey).’ By W. P. D. Stebbing, Hsq., F.G.S.

3. ‘Coal: a new Explanation of its Formation; or the Phe-
nomena of a New Fossil Plant considered with reference to the
Origin, Composition, and Formation of Coal-beds’ By W. S.
Gresley, Hsq., F.G.S.

The following specimens and maps were exhibited :—

Hand-specimens and microscope-sections of Rauenthal rocks,
exhibited by Prof. T. G. Bonney, D.Sc., F.R.S., V.P.G.S., in illus-
tration of Miss Raisin’s paper.

Specimens, photographs, and microscope-sections of Granite
Boulders from the Chalk of Betchworth, exhibited ype Was <1),
Stebbing, Esq., F.G.S., in illustration of his paper.

Specimens of Boulders from the Chalk of Norfolk, exhibited by
the Director-General of H.M. Geological Survey.

Specimen of the Granite Boulder from Purley, near Croydon,
from the Society’s collection; and a smaller portion of the same,
exhibited by Prof. J. W. Judd, C.B., LL.D., F.R.S. Also a micro-
scope-section of the same, exhibited by Prof. T. G. Bonney, D.Sc.,
RAGS. VE.GS.

Sheets 3, 6, 9, and 15 of the new Index Map of H.M. Geological
Survey (Scale: 4 miles to 1 inch); Sheet 299—Winchester of the
j-inch Map, New Series, and Sheet 81, Monmouthshire and Glamor-
ganshire, of Vertical Sections, presented by the Director-General of
that Survey.

XCIV PROCEEDINGS OF THE GEOLOGICAL society. [May 1897.

March 10th, 1897.
Dr. Henry Hicxs, F.R.S., President, in the Chair.

Conyers Kirby, Esq., Preswylfa, Bryngwyn Road, Newport
(Mon.); Joseph Coventry T’Anson, Esq., 25 Palace Chambers,
9 Bridge Street, Westminster, 8.W.; and Alfred James Hodekinson-
Carrington, Esq., Assoc.M.Inst.C.E., 34 Queen Street, Melbourne
(Victoria), were elected Fellows of the Society.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘ Volcanic Activity in Central America in relation to British
Earthquakes.’ By A. Gosling, Esq., H.M. Minister & Consul-
General in Central America. Communicated (through H.M. Foreign
Office) by the President.

2, «The Red Rocks near Bunmahon on the Coast of Co. Water-
ford’ By F. R. Cowper Reed, Esq., M.A., F.G.S.

3. ‘On the Depth of the Source of Lava.’ By J. Logan Lobley,
Esq., F.G.8.

Rock-specimens and Photographs were exhibited by F. R. Cowper
Reed, Esq., M.A., F.G.S., in illustration of his paper.

March 24th, 1897.
Dr. Henry Hicks, F.R.S., President, in the Chair.

James Negus, Esq., The Mining School, Camborne; and John
Francis Cleverton Snell, Esq., Assoc.M.Inst.C.E., 6 Thornhill
Crescent, Sunderland, were elected Fellows of the Society.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘ Notes on some Volcanic and other Rocks which occur near
the Baluchistan-Afghan Frontier, between Chaman and Persia.’
By Lieut.-Gen. C. A. McMahon, Y.P.G.S8., and Capt. A. H. McMahon,
C.LE.

2. On the Association of Glossopteris and Sigillaria in South
Africa.’ By A. C. Seward, Esq., M.A., F.G.S.

3. ‘Notes on the Occurrence of Sigillaria, Glossopteris, and
other Plant-remains in the Triassic Ro of South Africa.’ By
David Draper, Esq., F.G.S.

Wael: 53. | PROCEEDINGS OF THE GEOLOGICAL SOCIETY, CV

The following specimens were exhibited :—

Rock-specimens, Microscope-sections, and lLantern-slides, ex-
hibited by Lieut.-Gen. C. A. McMahon, V.P.G.8., & Capt. A. H.
McMahon, C.8.1., C.1.E., in illustration of their paper.

Plant-remains from the South African Republic (from compara-
tively short distances from Johannesburg), exhibited by A. C. Seward,
Esq., M.A., F.G.S., in illustration of the papers by himself and
David Draper, Esq., F.G.S.

Rock-specimens from Mexico and Nevada, exhibited by O. H.
Howarth, Esq., F.G.S.

April 7th, 1897.
Dr. Henry Hicks, F.R.S., President, in the Chair.

Capt. John Hamilton Anderson, Mandora Barracks, Aldershot ;
and Capt. Arthur Henry McMahon, C.S.I., C.LE., 87 Cadogan
Gardens, S.W., were elected Fellows; and Dr. Anton Koch, of
Budapest ; Prof. A. Lacroix, of Paris; and Prof. Count H. zu
Solms-Laubach, of Strassburg, were elected Foreign Correspondents
of the Society.

The List of Donations to the Library was read.

The Presiprenr then left the Chair, which was taken by Prof.
T. G. Bonney, D.Sc., F.R.S., V.P.G.S.

The following communications were read :—

1. ‘On the Morte Slates and Associated Beds in North Devon
and West Somerset.—Part II.’ By Henry Hicks, M.D., F.RS.,
P.G.S. With Descriptions of the Fossils by the Rev. G. F . Whid-
borne, M.A., F.G.S.

(The Presrpent resumed the Chair after the Discussion of the
above paper.)

2. ‘The Glacio-Marine Drift of the Vale of Clwyd.’ By T.
Mellard Reade, Esq., C.E., F.G.S.

The following specimens were exhibited :—

Fossils, exhibited by the President in illustration of his paper.
Boulder Clay Foraminifera and Rock-specimens, exhibited by
T. Mellard Reade, Esq., C.H., F.G.S., in illustration of his paper.

VOL. LIII. h

xevi PROCEEDINGS OF THE GEOLOGICAL soctntTy. [Aug. 1897,

April 28th, 1897.
Dr. Heyry Hicks, F.R.S., President, in the Chair.

H. F. Bulman, Esq., Byermoor, Burnopfield, R.S.0., Co. Durham ;
and Christian Adolph Heussler, Esq., Kalgoorlie, Western Australia,
were elected Fellows of the Society.

The List of Donations to the Library was read.

The PrustpEnt, referring to the exhibits of models of the dorsal
and ventral aspect of Triarthrus, said that these had been prepared
and sent to him by Mr. Charles E. Beecher, of Yale University
Museum. He was sure that they would prove of great interest to
the Fellows, who were well acquainted with the extremely careful
work which Mr. Beecher had done in connexion with 7rcarthrus.

The following communications were read :—

1. ‘Note on a Portion of the Nubian Desert South-east of
Korosko.’ By Capt. H. G. Lyons, R.E., F.G.S. With Notes on the
Petrology by Miss C. A. Raisin, B.Sc. (Communicated by Prof.

Bonney, D.Sc., F.R.S., V.P.G.S.) And Water-Analyses by Miss E.
Aston, B.Se. (Jdem.)

2. ‘On the Origin of some of the Gneisses of Anglesey.’ By
Charles Callaway, M.A., D.Sce., F.G.S.

The following specimens were exhibited, in addition to thos
mentioned above :—

e

Rock-specimens and Microscope-sections, exhibited by Capt. H.
G. Lyons, R.E., F.G.S., in illustration of his paper.

A series of Microscope-sections, exhibited by Dr. C. Callaway,
M.A., F.G.S., in illustration of his paper.

Specimens of Flint-implements from the Test Valley, Hampshire,
and Thornton Heath, near Croydon, exhibited by A. E. Salter, Esq.,
iBioe., 2 .G.0: }

A specimen of Arborescent Carboniferous Limestone from Brentry
Hill, near Henbury, Bristol, obtained by Spencer G. Perceval, Esq.,
and exhibited by the Director-General of H.M. Geological Survey.

Sheet 20 (Killean) and Sheet 103 (Golspie) of the Geological

Survey of Scotland, l-inch map, presented by the Director-General
of H.M. Geological Survey.

Sheets Zwingenberg and Bensheim of the Sa Geological Survey

Map of the Grand Duchy of Hesse, presented by the Director of that
Survey.

Vol)53.] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. X¢evii

May 12th, 1897.
Dr. Henry Hicks, F.R.S., President, in the Chair.

William Robert Coleridge Beadon, Esq., Queen Anne Cottage,
Keswick Road, East Putney; Gerald Noél Brown, Esq., 8 The
Esplanade, Plymouth ; and William Earl Hidden, Esq., 25 Orleans
Street, Newark, New Jersey, U.S.A., were elected Fellows of the
Society.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘On the Gravels and Associated Deposits at Newbury (Berks),’
By E. Percy Richards, Esq., F.G.S.

2. ‘The Mollusca of the Chalk Rock: Part Il” By Henry
Woods, Esq., M.A., F.G.S.

The following specimens, etc. were exhibited :—

Fossil Teeth, Bones, ete., exhibited by E. P. Richards, Esq., F.G.S.,
in illustration of his paper.

Flint from Halling, near Rochester, exhibited by G. E. Dibley,
Ksq., F.G.S.

Vertical Sections, Sheet 82, by C. E. De Rance, Esq., F.G.S.,
presented by the Director-General of H.M. Geological Survey.

May 26th, 1897.
Dr. Henry Hicks, F.R.S., President, in the Chair.

John T. Smith, Esq., Green Lane, Padiham, was elected a Fellow
of the Society.

The List of Donations to the Library was read.

The following communications were read :—

1. «On Augite-Diorites with Micropegmatite in Southern India.’
By Thomas H. Holland, Esq., A.R.C.S., F.G.S., Officiating Super-
intendent, Geological Survey of India.

2. ‘The Laccolites of Cutch and their Relations to the other
Igneous Masses of the District.’ By the Rev. J. F. Blake, M.A.
F.GS.

xcvill PROCEEDINGS OF THE GEOLOGICAL socrETY. [Aug. 1897,

The following specimens were exhibited :—

Augite-diorites with Micropegmatite, from Southern India, ex-
hibited by T. H. Holland, Esq., A.R.C.S., F.G.S., in illustration of
his paper.

Igneous Rocks from Cutch, exhibited by the Rev. J. F. Bla‘e,
M.A., F.G.S., in illustration of his paper.

June 9th, 1897.
Dr. Henry Hicks, F.R.S., President, in the Chair.

John Ball, Ph.D., A.R.S.M., 18 Redshaw Street, Derby; and John
Isaac Lowles, Esq., Leverington Chambers, Coolgardie, Western
Australia, were elected Fellows of the Society.

The Names of certain Fellows were read out for the first time, in
conformity with the Bye-Laws, Section VI. Art.5, in consequence
of the non-payment of Arrears of Contributions.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘The Cretaceous Strata of County Antrim.’ By W. Fraser
Hume, D.Sc., F.G.S.

2, «An Account of the Portraine Inlier (Co. Dublin)” By C. I.
Gardiner, Esq., M.A., F.G.S., & 8. H. Reynolds, Esq., M.A., F.G.S.

3. ‘Some Igneous Rocks in North Pembrokeshire.’ By J. Par-
kinson, Esq., F.G.S.

The following specimens were exhibited :—

Fossils, Rock-specimens, Microscope-sections, and Photographs,
exhibited by W. F. Hume, D.Sc., F.G.S., in illustration of his

aper.
: Fossils, Rock-specimens, Microscope-sections, and Photographs,
exhibited by Messrs. C. I. Gardiner, M.A., F.G.S., & 8..H. Rey-
nolds, M.A., F.G.S., in illustration of their paper.

Rock-specimens, Microscope-sections, and Lantern-slides, ex-
hibited by J. Parkinson, Esq., F.G.S., in illustration of his paper.

Vol. 53.] | PROCEEDINGS OF THE GEOLOGICAL SOCIETY. Xcix

June 23rd, 1897.
Dr. Henry Hicks, F.R.S., President, in the Chair.

A. Vivian Moore, Esq., The Club, Kidderminster; and David
Woolacott, Esq., M.Sc., 156 Roker Avenue, Sunderland, 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, Sect. VI. Art. 5,
in consequence of the non-payment of Arrears of Contributions :—
J. F. Braga, Esq.; Dr. J. C. 8. Burxrrr; A. Jounstony, Esq. ;
EK. M. Jonus, Esq.; T. R. Mappison, Esq.; Rev. H. E. Manpocx ;
P. J. Ogus, Esqg.; J. F. Pacun, Esq.; J. Porn, Esq.; H. K.
Spark, Hsq.; and the Rev. B. WiLxKinson.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘ Notes on a Collection of Rocks and Fossils from Franz Josef
Land, made by the Jackson-Harmsworth Expedition during 1894-
967 By E. T. Newton, Esq., F.R.S., F.G.8., & J. J. H. Teall,
Hsq., M.A., F.B.S., V.P.G.S.

2. ‘ Deposits of the Bajocian Age in the North Cotteswolds.—
I. The Cleeve Hill Plateau.’ By 8.8. Buckman, Esq., F.G.S.

3. ‘Pleistocene Plants from Casewick, Shacklewell, and Grays.’
By Clement Reid, Esq., F.L.S., F.G.S.

4. «An Explanation of the Claxheugh Section (Co. Durham),’
By D. Woolacott, Esq., M.Sc. (Communicated by Prof. G. A. Lebour,
M.A., F.G.S.)

The following specimens and maps were exhibited :—

Rocks, Microscope-sections, Fossils, Photographs, and Water-
colour Sketches, exhibited by Messrs. E. T. Newton & J. J. H.
Teall in illustration of their paper.

Messrs. W. & A. K. Johnston’s Geological Map of the British
Isles, presented by them; and 4 sheets of the Geological Survey
Map of Roumania, presented by the Director of that Survey.

VOL. LIII. a

4

wEoctt) gel We ee EY MOE 2 eee

DMIsSION AND PRIVILEGES —
OF

FELLOWS OF «HE GEOLOGICAL SOCIETY OF LONDON.

_ Every 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
the Certificate must have a personal knowledge of the Candidate.

z Fellows on election pay an Admission Fee of Six Guineas. The Annual Contribu-
ss tion paid by Fellows is Two Guineas, due on the Ist of January in every year, and
payable in advance; but Fellows elected after the month of February are subject only
_ to a proportionate part of the Contribution for the year in which they are elected,
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
publications of the Society: at a reduction of 25 per cent. under the selling prices.

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.: see also
next page. Under certain restrictions Fellows are allowed to borrow books from the
Library.

Publications to be had of the Geological Society, Burlington House.

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TRANSACTIONS. to the Pees TRANSACTIONS. to the Fellows.

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ak fate) 22 4a ed Pp Ere ok pee ee OS al SV OLUVIEES Part: 4-5... ic Ash cdeecuueesewecees 010 0

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me CATALOGUE OF THE LIBRARY, 1880. (620 pages 8vo.) Price 8s. Od.

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“CONTENTS

% “ =

Soe a | PAPERS READ.

Pe eB. Mr. John Parkinson on et Rocks in “North Pembrokeshire. (P
Peete fen.) ARAN EU, Gi sR pln Pesta ote ce

arg.

84, Messrs. E, 'T. Newton & J. J. H. Teall on Rocks and Fossils from Bra
AO: aa ‘Tosef Land. (Plates XXXVIL-XLL) shisha cy te
$2 Fa 35, Messrs. C. I. Gardiner & 8. H. Reynolds on the Portraine peESD Co. a li
os i (Plates KLE @ AU.) oie i a fis
: i

—

(Tir.erace, Contunts, and Inpux to Vol. LIII.)

[No. 213 will be published next February. |

hands. Unless this is Aig it t will be in the discretion of the Officers to return te
communication to the Author for revision. ; a

oo 4: from Ten o'clock until Five, except during the first two weeks in the
2 of Septeinber, when the Library will be closed for the purpose of
the Library is also closed on Saturdays at One P.M. during the months of A
and September. It is open until Eight y.m. on the Days of Meeting for
loan of books, and from Eight p.m. until the close of each: mere fe
sational purposes only.

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