= “Ei, . aH ee ™ “ere,” “”

see he OY le ee ee PP
Me ie te Ci ee A Fe as - “er Vs = te ~~ »*
-- wa : ee Ne Gin ete a ic I eM DR IY I

Pe he) ee eter Oe vr
= Hoe tem npn tea eben hor anally 12) nro Or Ge MF ee ee . “4 a
, ane = notion Pom po ent dy tion. pair i ea Rea i re BaD edie Bete Bh Se Ae ee Bele PA m+ Pqee eR e a al :

4 at eRe O- e ~ w aa o~ ern ee eee cee ee ed MA -tn doc tle D-H 2 et Ne ee ee

aed - > Ral a nit Dahan Hm Melly ae Bote enn tite .
-—_ sabe thnn beet Ree ap ee oe Son. ~~ tow ace agate eee ee Se Se) ES eaten

Open be oe Ante En eae ly Yeah”
rea eo ea eB ties ta tarde He #
Foyer eee tom irate tol ae a nan a Seok ie 7
oF Seed ioe ME Mee Modem in foe rate A . 5 mates : 5 a as >

- ~ tachi rm Na a Pns Want > fon gy Aad et a ag a Mal ee ee ee ee ee sal

poet RT eR ee etm ae ao BND Hho

ns ee tpt Hane Rett ar Hn ee ea My . ¥
we oe SS : - wr r -

pa eto Pt . Syn BaP es nate Paha POET rN eNO NS aruda

a a Sea De ee ee Te aaa eae
eFainiparnian irae nanos 2 ed
ec aipntn in tin Ba hpi Tye se ON tpt AICO Metersien Hat NO -Se Ap Aen pint Co A Me RDA Gp Ae tanto AA Sp taal hs a tasty Al ip or bait APN Pl tn es Bplay hata on Mean pe Pale Me pate et
S etalta he Rn A mint _grernadyan meni ee ered ew eal Saleen iare aac maya take Ade tee Aloette tht toca Mer to Pe er ae wen eee
eS eh ee ed toe ak een eee ee tT NE en arate pete aes atintin Mine
: Ne aM tal @ Rae S ntl CN? SA ALY MIRE 8 React” # NS A ee Tre NE RP BA ARR AI EEE AO OR PCE RN
ene Ae n-ne tn yt Binet Oy a2 + a T= rs aa Aa Mot Se Be Be ~~ eth het th tl MNP tna it la My ema a tei oe path a ie tthe Arete arena ;
* ey we: — ans

pane tne hay ate R tenia ae BOM n npr tel De Bo Rae aN lade ens

A Pererdares Sent PP NS aa Sastigne a <i oti on Aamashe Deneiaa sees a
> ~ / ni y ~ a aca ; ee ee Se eae ee ee ao

- ee SEN Sea ees
. ee Tote tn eat BE Ketel toe™ «

ate Soa eat walt Hoe

ee eee
Ne ee ee eed

Ae ten NI mB
rere

Pn ei Aen atte Son f
en ttintindite eT

~ Nt
~~

Se ae
gE PT
a endian ell

~~“ are
per pen’ Pe +

ee

Aslan Gn water et
eS ened fac lnc pie A taht oat eS Se ee ws
Pa We eer Man ee eG ee ae ce a a a - Ran Bh ln a ae tn a ato Ge Pay
ee a ale ae ear 2D So een PD + tet * Se a apaaelie’
<n wl oe Ne PPI B Oem > O- AD te 0 Ot 6 Pange Sp nies ee oe ox
7 - et Atm De Te Rp Pe ten teat tenn thames > ein eh
a a ee rn ee
_ agit Rath

2p at

an Qm 4 ee ~ wP.: ae
pe hath a Deen F028 Pete Be Remndl- Sete heh Toe
Ra! Om .'

ne ee

Allah theta Apt
~~ Fe NP J
woes oP ad tae nena ae lated ata i
“a : FS Re EN a tea Pee Pete
SP ale ek a Pin Cinna Roh Dn al

Sant Baan. ean

eB nla
Se
Ag ome est r 7d . - Mate? reo tot oe:
‘ ee eel
> —— eS en oad ‘~*

7
> ee - Ts - ¥ a . - 4 - pers tw gy . . an P J y /
. . : . » Pla Oa DLP LOGE Pt MMOS “te
- Sa ee et : *
te we Se te et A ee eee * > Sh Ay teh Heh
Shey gdh FR Ge mete
ee eee es a es

THE

OF TIE

GEOLOGICAL SOCIETY OF LONDON.

EDITED BY

THE PERMANENT SECRETARY OF THE

SOCIETY:
A“

Quod si cui mortalium cordi et cure sit non tantum invextis Refrere, atque iis uti, s@W*ad/ulteriora
penetrare ; atque non disputando advyersarium, sed opere naturam Vi cer ani qi bw Bic :

opinari, sed certo et ostensive scire ; tales, tanquam veriscientiarum filii, is-(sividebitur) se adjungant.
—Novum Organum, Prefuatio.

VOLUME THE SEVENTY-THIRD,

For 1917.

LONDON :
LONGMANS, GREEN, AND CO.
PARIS: CHARLES KLINCKSIECK, 11 RUE DE LILLE.
SOLD ALSO AT THE APARTMENTS OF THE SOCIETY.

MCMXYVIII.

“tst

OF RI CHTCS

OF THE

? CU Tah aL SOCIETY OF LONDON.

Ne

Elected uae 16th, 197,

ADAAA AAA

eae

Persient
Alfred Harker, M.A., LL.D., F.R.S.

Wice-Jrestdents,

R. Mountford Deeley, M.Inst.C.E.
Edwin Tulley Newton, F.R.S.

Prof. William Johnson Sollas,M.A.,LL.D.,
Se.D., F.R.S.

| Arthur Smith Woodward, LL.D., F.R.S.,

HES.

Secretaries.

Herbert Henry Thomas, M.A., Se.D.

Foreiqu Secretary.

| Herbert Lapworth, D.Sc., M.Inst.C.E.

Creasurer.

Sir Archibald Geikie, O.M., K.C.B., D.C.L., | i James Vincent Elsden, D.Sc.

LL.D., Sc.D., F.R.S.

COUNEIL.

Charles William Andrews, D.Se., F.R.S.

Prof. John Cadman, O©.M.G., D.Sc.,
M.Inst.C.E.

Prof. Charles Gilbert Cullis, D.Sc.

Arthur Morley Davies, D.Sc., A.R.C.Se.

R. Mountford Deeley, M.Inst.C.H.

James Vincent Elsden, D.Sc.

Prof. Edmund Johnston Garweod, M.A.,

Se.D., F.R.S.

Sir Archibald Geikie,O.M., K.C.B., D.C.L.,

LL.D., Sc.D., F.R.S.
Walcot Gibson, D.Sc.
Alfred Harker, M.A., LL.D., F.R.S.
Finlay Lorimer Kitchin, M.A., Ph.D.
George William Lamplugh, F.R.S.

Herbert Lapworth, D.Se., M.Inst.C.E.

- John Edward Marr, M.A., Se.D., F.RB.S.

Edwin Tulley Newton, F.R.S.

Richard Dixon Oldham, F.R.S.

Robert Heron Rastall, M.A.

Prof, Thomas Franklin Sibly, D.Se.

Prof. William Johnson Sollas, M.A.,Se.D.,
Li.D., BRS.

Sir Jethro J. Harris Teall, M.A., D.Sce.,
LL.D., BRS:

Herbert Henry Thomas, M.A., Se.D.

Samuel Hazzledine Warren.

Arthur Smith Woodward, LL.D., F.R.S.,
E.L.S.

48 manent Secretary.
L. L. Belinfante, M.Sc.

Librarian.
C. P. Chatwin.

Clerk.
M. St. John Hope.

Assistant tn Ltbrarp.
Arthur Greig.

STANDING PUBLICATION COMMITTEE.
Dr. A. Harker, President.

Dr. H. Lapworth,

Dr. Herbert H. Thomas.

Dr. F. A. Bather.
Prof. J. Cadman.

Prof. C. G. Culiis.

Dr. J. V. Elsden.

Dr. Walcot Gibson.
Dr. F. L. Kitekin.
Mr. G. W. Lamplugh.

} Secretaries.

Mr. E. T. Newton.

Mr. R. D. Oldham.

Prof. T. FE. Sibly.

Prof. W. J. Sollas.

Sir Jethro Teall.

Dr. A. Smith Woodward.

TABLE OF CONTENTS.

Page
Barurr, Francis ArtHur. The Triassic Crinoids from New
deatmd, collected by Dr. C. T. Trechmann *,.....:..-..:..-. 247
Buckman, 8.8. Jurassic Chronology: I. Lias. (Plates XX VI-
MOM re ck i ce ee Te eRe ate eee eRe Nee tN SU cet a eva: SN = 257

Burton, THomas Harris. The Microscopic Material of the
Bunter Pebble-Beds of Nottinghamshire, and its Probable
SemmarremnNOYEIOCUE ha 0) Raat Salt toe 2 vee oe vee wee eden ihe O80

Dixny, Frank (& T. F. Srpty). The Carboniferous Limestone
Series on the South-Iastern Margin of the South Wales Coal-
preammmeeetes ALI XV ED) eins oP ade eee te ene tees 111

LonGsTaFF, JANE. Supplementary Notes on Aclistna De Koninck
and Aclisoides Donald, with Descriptions of New Species.
meee MCP rein cre phy 8s 25) 08a, Sen Mach gi ace Goeks Siole Dade ewes 2 59

Parsons, Lronarp Mines. The Carboniferous Limestone bor-
dering the Leicestershire Coalfield. (Plates VII-XI)........ 84

SARGENT, HENRY CRUNDEN. Ona Spilitic facies of Lower Car-

boniferous Lava-Flows in Derbyshire............ gins, & Bee os It
Sipty, THomas Frankuin (& F. Drxey). The Carboniferous
Limestone Series on the South-Kastern Margin of the South
Pes toalnield, (Plates XIX VI)... oe ei ieee 111
SmitH, Grarron Exuiot. On the Form of the Frontal Pole of an
Endocranial Cast of Eoanthropus dawsont ....... 6.00 c cece 7

SWINNERTON, Henry Hurp (& A. E.TRurman), The Morphology
and Development of the Ammonite Septum. (Plates II-IV).. 26

‘TRECHMANN, CuHarurs Tayztor. The Trias of New Zealand.
Bee ieee VL ON aks oo cle d CSivicw a aeds ducal pits lesed 165

iv TABLE OF CONTENTS.

Page
TRUEMAN, ArTHUR E1isan (& H. H. Swinnerton). The Mor-
phology and Development of the Ammonite Septum. (Plates
PION ain eo pes weve 4, © oi lyin @ ble nn 6 mye ee 8/62 1 per 26
Woopwarp, ArtHtur SmirH. Fourth Note on the Piltdown
Gravel, with Evidence of a Second Skull of Eoanthropus
PUGEAON Ts MEALS Ty) Ose picts iets «ode tee erste, eee Pe A 1
PROCEEDINGS.
Proceedings, of the Meetings ... ...\.. i240: 5:40 220 eee 4, xe
PATTY ECOPONG ) pb iia.g Wiese « beg vise Sauk bien we Re Bg he xlil
Lasts.of Donors.to the Library .........%.).0... <a xvill
List of Forsign Members: 0... 02.5 daahoesclt. Meee de ee XXVi
Last-of Foreion Correspondents. : . s..-..5 ast «ose XX Vil
fast of Wollaston Medallists .. .... 064.5. d6)a0eus>9 2 See XXVili
Last of Murchison Medallists...........+0..23 ) 0816 eee XXX
Mist-of Lyell: Medallists 2. .......'s0.5 00'8t Sie Xxxii
Lists of Bigsby and Prestwich Medallists ..........0..0.5 oa) SE
Applications of the Barlow-Jameson Fund and Awards from
the Daniel-Pidgeon Fund. . ..3. . 22.0503 9 os oe XXXV
Fimaneial Report «oii. cag ane areas as ws Se HS ag te XXXV1
Awards of the Medals and Proceeds of Funds .............. xliv
Anniversary Address of the President... . s«0> +0 <g4 One lv
Crick, GrorGe C. [Recent Researches on the Belemnite
GMB Sees a iafen yea a wee » dos Scot) ere er iv
GEIKIn, Sir ARCHIBALD. [Presentation of bust of] ....... : ix
Jackson, JonN WitFrip. [On Facetted Pebbles from Pen-
dleton (Lancashire) |,"..:,... 5s «scene seis cee oe ee i
McNeit1, BEpForD. [Announcement of decease of] ...... 4
ROUTLEDGE, ScorEssBy. ([Physiography, etc., of Easter
(ESHECTG (Ea oea aerate aM SM) Aakagae ee x
SnHepparD, THomas. [British Geological Maps as a Record
Ghats Advance of Geology)... saute son aceis eee cee c

SToPESs, Marre C. [Recent Researches on Mesozoic ‘ Cycads’
PRSRINEEAEAECH) a ir. so sc ok nas 4 8 ERURIE Oe chain aoe Mie ata vi

LIST OF THE FOSSILS FIGURED AND DESCRIBED
IN THIS VOLUME.

Name of Species. | Formation. | Locality. | Page

MADREPORARIA RUGOSA.

Canima cl. patula, fig. 4 &1\ Ay oe
ee ee... | | Cabboniiovoms f tiaknall 107
Diphyphylium ef. concinnum...| mmesvone =| | Breedon Cloud .}| 108
CRINOIDEA.
Enerinus hyatti, fig. 8 ......... Upper Trias ...|_ California ...... |) 251
Entrochus ternio, sp. nov.,
Wc S10 Se ee aduka Bed Hokonui Hills. 249
undatus, sp. nov., figs. 1 ef Ss--|) Highty-Kight |
CLES ocohdedoges een eae re 4 Valley mecca. | 247
Isocrinus argenteus, sp. nov....| Middle Trias...| Nevada ......... | 254
cupreus, sp. nov., fig. 14.) | 7, i: a Poo
Re ue, sp. nov. fie. 15. Upper Urias 13) Mabka seer): 1 256
—— trechmannt, sp. nov., figs.
Sete ics oc av cantata dayne Kaihiku Beds ..... Hokonui Hills . 252
Bracniopopa.
Pseudomonotis- | Bichwcad
Cenothyris sp., pl. xxiii, fig. tl a ag ( cee 218
Dielasma cf. himalayana ...... I) | (Hokonui Hills | 217
-—— zealandica, sp. nov., pl.| | |
CG ee ee | } Kaihiku Beds...!{ Hokonui Hills .| 217
Halorella zealandica, sp. nov.,| | |
Piesex, fies, La-3 ...... +. i) | Caroline Cutting] 216
ee f Mytilus-proble- | { Highty-Kight
eae fig, t :.... | { maticus Bed. Valley bei. 216
Hectoria bisulcata, gen. et sp.|
nov., pl. xxv, figs. la &10.| Oarnic—Noric...| Otamita ......... 235
cuneiformis, sp. noy., pl.'
muy, fies. 4@¢&40...........- ' Bajocian, &c. ...| New Zealand ...| 2387
tumida, sp. nov., pl. xxv, \ (
Pra wtestatcntstecckesce<| | | Hokonui Hills .| 236
Mentzelia kawhiana, sp. nov., }Rhetice ......... 4
pl xxii, figs. LO@& 100...) | | KawhiaHarbour| 228
--— ef. ampla, p). xxiii, fig. 9. ) | KawhiaHarbour| 228

Vi

Name of Species.

FOSSILS FIGURED AND DESCRIBED.

| Formation. | Locality.

Bracutopopa (continued).

Mentzeliopsis horrida, gen. et{”

sp. nor., pl. xxi, figs. 17&18
—— spinosa, sp. nov., pi. xxiii,
LECT ES AR bes Si ea oct
fietzia Ail pl. xxiii, fig.

ee oy

ie XXIV, mee 3.

cf. austriaca, pl. xxiv,
(LTE, 2 ay SRO ea ee
(2) caroline, sp. nov., pl.
Exil, figs. 19 a—20 .......8....

diomedea, sp. nov., fig. 3

Supls, Hes. AH? soc. cee
— fragilis, p\. xxiv, figs. 10-
—— gypaitus, pl. xxiv, fig. 4.
kaihikuana, sp. nov., pl.

xxiv, fig. 15

nelsonensis, sp. nov., pl.

58116 TEE oe Ae } NESS ok { ton Seen 2
otamitensis, sp. nov., pl.
Rag, fgg. Od 01910 1522.) .2.. Oarnige . arches Otamita <2
suessi, var. australis nov., Bo es { Mount Hesling-
pl. xxiv, figs. 13 a-14......... } Halobia Beds ... GON © dos sceceen
Spirigera kathikuana, sp. nov.,
| SIE Gel POA Mae ai ee Sega Kaihiku Beds...| Caroline Cutting)
manzavinioides, sp. NOY.,| \
pl. xxv, figs. 7a &7O ...... Otamita, -.28
—— wreyi, pl. xxv, figs. 6a & Mount Hesling-
GiBageree cine oct Sicwaaromse cue. O > tON 52 -pateeee
Terebratula cf. hungarica, pl. f roe ne | :
5.4 (UBER TTA > erga aap NGS aR Otamita ...2..48
pachydentata, sp. nov., | |
Pl oR Oe Ob eee oe nae ) \ 'Otamita <2 ce

Anisocardia parvula, sp. nov.,
pl main fips TEs.
Anodontophora angulata,
Hoy, Dl xa, Teel) Fo.
edmondiiformis, sp. nov.,
UNE, ES | precise a seca se
-— ovalis, sp. nov., pl. xxi,

fig. 9

ee ay

Cardiome “pha ( 2) m uggetensis,

sp. nov., pl. xxi, fig. 7

se eeee

Cassianella sp., pl. xxi, fig. ee

Daonella indica, pl..xx, ‘fig. 7 7|
& pl. xxi, fig. 5

|
i

| f
Kaihiku Beds.. ; Caroline Cutting
i

|

| Halobia Beds .. aes wie
cl; Noric (2) ......--- ge Hesling-
Ol” ...0seseee

Lower Carnic(?)| Mount Potts ..

=)
:
|
|

Kaihiku Beds = Caroline Cutting,
Rhewtie ieee. New Zealand . |
Kaihiku Beds Caroline Cutting
Worie(?), 222: Hokonui Hills .
| Kaihiku Beds... { ee tes oa

LAMELLIBRANCHIATA.

\

| Garnic ,oda0Gaeee |

| |

Nugget Point...
Otamita
Caroline

Cutting

Kaihiku Beds..

wee eee

"|

Mount Hesling-!

|

|

4 -Otamits 22. 226
|
|
|
\

Page

[230
230

FOSSILS FIGURED AND DESCRIBED. vil

Name of Species. | Formation. | Locality. Page

LaMELUIBRANCHIATA (continued).

Halohia cf. austriaca, pl. xxi,

OPE AMM os cca 2.5 onesie soins cae | Otamita,. .....:5.. 200
—~ hochstetteri, pl. xxi, fig. | Mount Hesling-
Eom hace 2t hols agescn sees fOUi ee ats cei, LOO

ettteli, var. zealandica
mov, pl. xx, fic. 6 & pl. xxi,
nis.) 20h er
Hokonuia limeformis, gen. et
Sp. uov., pl. xx, fig. 4 & pl.
ees. a, 20, oD ...:
rotundata, sp. nov., pl.
xx, figs. 5a-5b & pl. xxii,
Mees (f) 40,40 .........

New Zealand ...| 197

WSCaEMIC focc..s.po: 4 New Zealand ...| 204

| | New Zealand ...| 205

Leda semicrenulata, sp. nov., |
i. Zea | Otani: 72/5. 191
Lima (Limatula) of. gaia | Mount Hesling-
Di Sa | BOIS ese 206
Macrodon cf. curtoniz, pl. xxi,
1g. 1 ek } \ Otaniita ......... 191
Megalodon globularis, sp. nov., |
Dvn ie Lower Oarnic...| WairoaGorge...| 209
Monotis salinaria, pl. xix, fig.| \
1 covet bch seer | 195
, var. hemispherica x
ee te 263 PNoric (Phares... : : Ocwicm aires. ake 4 196
, var. intermedia | |
Hove pl xx, ae. | ....... eitee ) \ | 196
Myophoria heslingtonensis, sp.| \ (Mount Hesling-
Mover mt, fi, 9.2.2... | COMM Janenc ses 211
nuggetensis, 8p. nov., pi.
BEI ME occ n cnc s- cane ees Nugget Point...) 210
otamitensis, sp. noy., pl. |
SS) il AC | | Olam Ne ea. 21]
Mytilus (Y) mirabilis, sp. nov., | Highty-Hight
pl. xx, figs. 9a & Ci ae Lo : 4 Valley. vice. 202
-— problematicus, pl. xx, fig.| [“* Rene Toot | Highty-Hight
“ooh ot DL ee | Wallleyescc.<2--1 UL
Paleocardita quadrata, sp. |
Moma oom, TLE eo. . Nugget Point...) 212
Pale@oneilo otamitensis, sp.
miverwe., XKI, fie. Zhe... Otamita ......... 190
ef. preacuta, pl. xxi, fig.
oo ee ) \Otamita’.........| . 190
7 Paléocardita
eee xeiifig. 18 ...... { Bede 3: s-5-4-28: Nugget Point...| 206
Puma sp:, pl. xxii, fic. 11 ...... Het arer 206
: Carnie ecy. 3. 7 Rey qs
Pleurophorus zealandicus, sp.|{ ~~
Movi xd, fo: 6... cscs... Oeamattes vcacecess 212
Pseudomonotis ochotica, pl. xix,| | ac
SS) [ONG oe | ‘ 1
waa ME aiuiccosiain Upper Noric ...| ; Wairoa Gorge...)
havi Abb oe 1 ay er | | (194
richmondiana, pl. xix, Nos Mount Hesling-
SSIS COS) ee } aca a eee { WOM Sen deen 194

vill

Name of Species. | Formation.

FOSSILS FIGURED AND DESCRIBED.

LAMELLIBRANCHIATA (continued).

Pseudoplacunopsis placentotdes,| \
sp. nov., pl. xxi, figs. 14 &
Wade pte vnsvabtnoake ce taes so ceeat

Carnie

GASTEROPODA.

Aclisina aciculata, pl. vi, fig. 6.

ashtonensis, pl. vi, fig. 9..

costatula, var. dubia......
delicatula, sp, nov., pl. v,
figs "OG OG ea aaa eee ee
elegantula, pl. vi, fig. 2. .

elongata, pl. v, figs. 10-
12

, var. cingulata, pl.
figs. 13 & 14

mavens:

a a)

varians, pl.

- — faber, sp. nov.,
digs. 45 Dig G25 oes. ihc
micula, ie nov., pl.
HIG. G1) GGT Cece.) cor eee
(2) multivolva,
pl. vi, figs. 7 & 8
—— pulchra, pl.
2a—2b

Lower
Carboniferous.

~+-- Fn’

e = es Berine

0 SE Pa ERI 2 oN aos
pusilla, pl. v, fig. 9
similis, pl. v, fig. 8 ......
striatissima, pl. vi, figs.
3&4
Pee sp. nov., pl.
RAHN: ON es, Fee gah leet. eee <
tenuistriata, pl. vi, fig.
venusta, sp. NOV., p
Hie Sra Ons lame Re toner
Aclisoides (?) armstrongiana...
-—— striatula, pl. vi, figs. 10-
Be fahren aeS acacus anne eer
Bourguetia (?) arata, sp. nov.,| )
ji |= le eae me oe
Conularia sp., pl. xviii, fig. 1.) |
Coronaria spectahilis, sp. nov.,
1) BGS is 1a I co a
Dentalium sp., pl. xviii, fig. 2.
Patella (?) nelsonensis, sp. nov.
pl. xviii, figs. 8a & 8 ......
Pleurotomaria (Sisenna) hec- \
tori, sp. nov., pl. xviii, figs.
DO-DE s stectsty Muda ddtons cone
hokonuiensis, sp. nov.,
pl. xvii, figs. 6@-6c.........
Trochus (Tectus) marshalli,
sp. nov., vl. xviii, fig. 7

ag

be a

| Locality. | Page
| Otamiite: ues | 209
(Gillfoot, Car-
luke:.... Sposa 1
Ashton Vale
Colliery ...... 78
Moss Mullock.... 70
Glencart, Dalry.| 71
Law, Dalry...... 74
Lauriston ...... 72
Glencart, Dalry; 73
Lauriston) 2a.-5| 73
Glencart, Dalry. 70
4 Kilwinning...... 71
"Moss Mullock.... 77
Tourmal oes 68
|
Robroyston ..... 68
Law, Dalry...... 72
| Law, Dalry...... 71
|
Law, Dalry......,
Moss Mullock...) 74
Penton Linns.. 76
| Law, Dalry 69
Law, Dalry...... 82
\ Vario’, See 78
(Mount Hesling-
[- tom. Soe 188
{ Otamiita, Seeeeee 189
Mount Hesling-
|” ton ee 187
[ Otamitay ic..eom 188
{ Lighty-Hight
\ Valley <s.ccegs 185
| (
| 186
4 Otamita.....1.%
/ | 186
\ | \ 187

FOSSILS FIGURED

AND DESCRIBED. 1x

Name of Species. Formation. Locality. | Page
CEPHALOPODA.
Acanthopleuroceras rursicosta,
nom. nov., pl. xxvi, fig. 4...| Middle Lias Leckhampton ...| 286
Arcestes ef. rheticus, pl. xvii,
55 2 ca 514 seicidnian cise Ob a Albatross Point. 182
Arvetites turgescens, sp. nov.,
pl. a fig. 2 & pl. xxxi,| } Lower Lias...... Barrow Gurney.| 296
cl 2 3 Gao ae
“eee anageneticum, sp. 300
nov., pl. xxxi, figs. 3a-3d. . : :
—_ flavum, eee Dias .......-2...++. Juyme Regis
Jt3 ( e 298
Jortunatum, sp. nov., pl.
xxvill, fig. 4 & pl. xxxi, figs. “Toes u Bee Paulitiom ones. 3801
.Jsu 2 ne
Aspidoceras perarmatum, yl.
ER Ce ee UPASSIC 18.605 Faringdon ......, 53
Aulacoceras sp., pl. xvii, figs. /
ol a2 Se Noric & Carnic.| New Zealand ...| 184
Cladiscites sp., pl. xvii, fig. (Mount Hesling-
ont DpH oon. sonia’, ee
Clydonautilus (Proclydonauti-| + Carnic............ 4 |
lus) cf. spirolobus, pl. xvii,| | | |
ib 2 (25 | | Nugget Point... 182
Celoceras fonticulus, fig. 8 (4).| \ | (Whitby .... 39
Pettos, fig. 8 (5)..........-. | |, Baden 020.250. 39
Cosmoceras jason, pl. iv, fig. 10} | J : } Woburn Sands. 53, 55
Dactylioceras commune, figs. 3— r Re ope
11, pl. ii, fig. 2, pl. iii, figs.| | |
People ty, fie. A5!......... } Various, ...ch4.. 31 et seqg.
Deroceras bispinigerum, nom.
SI AO 7 Witage un f.5is scones Wartous :2.6c.6: 302
Discophyllites cf. ebneri, pil.
LE 7 Caeare s 4 c< 288 Otamitas<.. A 184
Gleviceras auritulum/glevense,| \ (
gen. nov., pl. xxx, figs. 5 a- |
56, & pl. xxxi, figs. lal). ' Charmouth...... 291
— glevense, nom. nov., figs.| | +.
4, 5 Me eO ph xxvii, fied pa sega ehinc 1h 4
2-3, pl. xxviii, figs. 1-2, | |
plex, fic. 3, & pl. xxx,
Ms. coeds vets ise ve oeae Hi le WROTE” soa 289
— riparium, pl. xxx, figs
Lo) lv ee eee Lower Lias...... Aston Cross ...| 292
Grypoceras cf. mesodiscum ...| Carnic............ Otamita ......... 181
Guibaliceras guibalianum, gen.
mane tis 14. 18... 0. Lilaaee es keke Various: ......- 293
Hoplites auritus, pl. iv, fig. 8 .| \ ( Cambridge ..... 52
—. raulinianus, pl. iv, fig. 7.| | | Folkestone ...... 53, 55
splendens, pl. iv, figs. 4-6) } Jurassic ......... ie WANES! 2s tty. | 52 et seqq.
Keplerites calloviensis, pl. iv,| | |
OL Lede ee ee ) \ Ashton Keynes.; 53
Leptaleoceras leptum, gen. et |
sp. nov., pl. xxvi, figs. 1 a- {i A 8 A Re WAPIOUS( casei 285

x FOSSILS FIGURED AND DESCRIBED.

Name of Species. | Formation. |

Locality.

CEPHALOPODA (continued).

Microderoceras depressum.,} \
nom. nov., pl. xxx, figs. la-| |

inflatum, sp. nov., pl.| j

xxviii, fig.3 & pl. xxix, fig. 1
—— rhodanicum, nom. nov...
septigerum, nom. uoy.,

pl. xxx, figs. 2a-26
Normannites _braikenridget,

[a Ae Ce OI mene ees Jurassic ......-..
Orthoceras sp., pl xvii, fig. 6 .| Carnic............
Oxynoticeras oxynotum, figs. 1,

2a-2b, 8, 9,15,&16 ...... L;

polyophyilum, figs. 3, 10, hac see peeeenc nee

“et ii Si ie sae Ae nee Se
Perisphinctes triplicatus, pl. iv,

Og So eee a ey eee Kimeridge Clay.
Polymorphites jupiter, fig.56b.| Jurassic .........

Psiloceras planorbis, pl. iv,| \
fig. 9
Radstockiceras complicatum,
gen. et sp. nov., figs. 6, 12,| |
21 & pl. xxvii, figs. 1a-18 .| )
Spheroceras brongniarti, figs.| \
S517 i play ep: Ton. |
Tragophylloceras loscomhi, figs.| + Jurassic
12-14 & pl. iii, fig. 6......... ie
Uptonia gamesoni, pl. iv, fig. 138
Victoriceras victoris, gen. nov.,
figs. 13, 19

)
rf

Ce ey

PRIMATES.

Eoanthropus dawsoni, fig. 2 & |
Bl, BPs. lO. sen seensss oes Piltdown Gravel/

(

| Barrow Gurney.

| Barrow Gurney.
?

| Cheltenham

weet etwas

Market Rasen .
Old Dalby
(Robin Hood’s
| Bay

|
| Radstock Grove.

| Sherborne

eeeeee

| Lyme Regis
| ?

Various

Piltdown:...42

Page

304

53
181

293
et seqq.

51
35

293

3 et segg-

EXPLANATION. OF THE PLATES.

PLATE PAGE
CrantiAL Bones AND Monars oF HoANTHROPUS
I pAwsonrI, ¥Tc., illustrating Dr. A. Smith 1
Woodward’s paper on that fossil ...............
PLATES

( APPARATUS USED IN SURVEYING AND LEVELLING THE )
Surraces or Sepra and oF Wuorts; Dacrv- |
LIOCERAS COMMUNE, AND SEPTAL SEC TIONS DRAWN
FROM THE SAME; DEVELOPMEN! OF THE SurTUM |

II-IV< or D. commune; and DeveLopMENT or THE} 26
Ammonite Septum generally, illustrating the
paper bv Prot. H. H. Swinnerton & Mr. A. H.
‘Trueman on the Morphology and Development

\ of the Ammonite Septum....... OY iets etait: alec)

ACLISINA AND ActrsorDEs, illustrating Mrs. Long-
pt { staff’s paper on those genera ................e00e } me

(Exposures aT TickNALL; THE SouruEerNn Fav tt \
| At Brempon Croup; Microscors-SECTIONS OF |
VII-XI 4 Dotomitic Limesronn: AND Map or THE Car- } 84
| BONIFEROUS LIMESTONE BORDERING TIE ee |
| TERSHIRE CoaLFiELD, illustrating Mr. L. M. |
| Parsons’s paper on that Tne at

(Craig Luianisney, Carry-On, mtc.; tHe Scarp- \
Face or Crrn-On av tHe Heap or Cwm |
Drarturn; MAcnHEN Quarry, E'c.; THE Goran
or THE Tarr BELOW Tarr’s Wei; Escare-
MENT OF THE Main Limesronn, Garti Woop;

View oF Quarry Norrnu or Miskin; |
RXV I GEOLOGICAL MAps ILLUSTRATING THH CarBonr- + 111
FEROUS LIMESTONE SERIES BETWEEN THE TAFF
VALLEY AND THE Ewenny AND Eppw VALLEYs, |
accompanying the paper by Mr. F. Dixey &

Prof, ‘I’. F. Sibly on the Carboniferous Lime-

stone Series of the South-Eastern Margin of |

the South Wales Coalfield ....... Patan ses Sieen

77 OOOO SY

-

X11 EXPLANATION OF THE PLATES,

Puatas _ Pacr
(Triassic CEPHALOPODA FROM New ZEALAND;

>
| Triassic Gasteroropa FroM N.Z.; Psevpo-
| monorrs AND Mownorrs; Triasstc LAMELLI-
XVII-XXV{ ~~ Brancus From N.Z.; Triassic BracHiopopa
{| From N.Z.; anp TrrAsstc SPIRIFERINZ FROM
| NZ, illustrating Dr, C. T. Trechmann’s paper
| on the Trias of New Zealand —-..seeeeeeee al

|
| 165

( LEPTALEOCERAS, ACANTHOPLEUROCERAS, 4D- )

| STOCKICERAS, GLEVICERAS, MICRODEROCERAS, |
XXVI-XXXI{ 8 AnzeriTEs, aND ARniocERAS, illustrating } 257

| Mr.S. 8. Buckman’s paper on the Chronology |

|... voli Hae iiss. asc ecco sD ase MP

PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES

Bre, —

to

=I

BESIDES THOSE IN THE PLATES.

Supposed hammerstone of flint from the Piltdown Gravel ...

Frontal pole of an endocranial cast of Hoanthropus, viewed °

MMBTERURIOT OBOE Pk Ree ork alee Se eet acts occa ninidle dandi'a oleae bac dewe'a

Plan of instrument used in surveying and levelling the
surfaces of septa and whorls [of Ammonites] ...............

SPELIOMEOL GHG SAME INSEFUINENE.. ..v<iecscccescccdesceccccsceeccoacees

Graph showing the average profile of the adult i aaa of
DVGRUMOCENES COMMUNE <0... sovncacertciecvoresssqusasonacevsgastes

Contoured plan of the adult septum of Dactylioceras
RENAME Ter a0 te slo Nose Sar, utseinc sites tien se gdon sanbeton ob cas sanees

Last two suture-lines of two ammonites showing the last
UMPeRICOnpetel VA LOTINGG 02. sc.ces <saaaes senedeeecnedeneeneees

Contoured plan of the second septum of Dactylioceras
RE REN A ER Pye B asoel sig abel vckenl Gals deivvalegnee d 28 SaAidclvatiuh ode cade oS ne

Graph illustrating the average profile of the second septum
PAPE ULOC EGOS Nan «saan tad nau ee wen aees see U re sce lice 's sce ake ks

Suture-line of Dactylioceras and Celoceras ........0.0.ccecececee
Development of the suture-line of Dactylioceras commune ...

Series of septal sections made from one of the latest septa of
PU EC TUCED Ob gts stranins civeca Mean Mat coe eaatasevs dash te oe gatewnnts

Section of whorl along the datum-plane of the same
SUIGUTTLENE SC GR ecicnOe ACR 1 eGR. Ate econ Get Dale Oana ae ea

PAGE

2

a

XiV

Fires. 12-14.

15 & 16.

Fig. Wes

Ly

bo

1)

HiGs.

Fig. 8.

Figs.

Fia. 14,

1 & 2.

PROCESS-BLOCKS AND OTHHR ILLUSTRATIVE FIGURES.

: PaGE
Development. of suture, ete. of TZragophylloceras los-
COMBE ov dig ea laces Costas cake uc en enee ee 46

Development of suture, ete. of Spheroceras brongniarti. 48
Section of whorl of Spheroceras brongniarti ............... 49

Sequence of Lower Carboniferous strata exposed at

Wicknall .....cg00. sheng sdee. coer sete ededeasee rr 89
Rough plan of Breedon Cloud Works .....:.............-. 98
Sketeh-map showing the topographical position of the

Leicestershire area relative to the Waterhouses

development .:.. 2.2.00. ences tote cesees aoe nese see 102
Caninia cf. patula Michelin ......2.......-+-.c0 eee 107
Geological map of the neighbourhood of Cardiff ......... 112
Vertical sections of the Carboniferous Limestone Series

on the south-eastern margin of the South Wales

Coalfield i 2200000... 0c002. betwen pokes os kee er 119
Horizontal section through the Carboniferous Limestone

Seriss*of Miskin 22.0.0). 0.022. .ccen-c ce 120
Horizontal section through the Carboniferous Limestone

Series of Cefw-On 0.200302. ccs sesnes ote eee 120
Section of the lower part of the Lower Limestone Shales,

stream below Coed-y-Mochyn ..........-..-+seesseseeeeenee 127
Locality sketch-map of New Zealand ...............0eceeeee 172
Diagrammatic section of Triassic deposits from South

Head, Shaw Bay, to Nugget Point \....:...-cheeeseeeenee 180
Interior apex of the ventral valve of Spiriferina

Aiomed ead, SP. MOV. s2- doce inxui.desesiae sas ests cee 222
Hectoria sp. from Carnic shales at Otamita ............... 233
Interior of apices of valves of Hectoria tumida, gen. et

SP. DOV. | vedccadecoeseesasve dacs telescebcemecey seer ian 234
Entrochus undatws, Sp. WO: <:.-...i2.s<sees eee st ae 248
Entrochus ternio, sp. MOVs i 20: vc0css2toa0e0ees oaks eee 248
FN CPUS LY GHG \. 6280s inc dds Seb bese dale nd oto ele pee 248
dsocrinus trechmanni, Sp: WOW. <.<ccs.00ts.0>-+s-0senee eee 248
ISCCTINMS CUUPT EUS, SP: DOW. | iiaes..\.cs0s-dyerees pesos’ eee eee 248

, LSOCTINUS GraviNne, ‘Bp; DOVs: ccijcceces ts svyaaapenteaaet ones eee 248

PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES. xV
Pace

Fic. A. Diagram illustrating the faunal sequences in the Domerian—
wlerian, (5 jee Git xc. osenl ease ce sas Risamashdadaedemepseects'ss.= 265

B. Diagram illustrating the faunal sequences in the Raasayan,

Wescranaspamelt Wieweraly. s.150es seat soc ioata dada Sede caev cuca ehh av 27
Fies. 1-7. Suture-lines of Oxynotoids and a Deroceras .............0008: 294

8-21. Suture-lines (skeleton) and radial lines of Oxynotoids...... 295

Map of Nottinghamshire illustrating the occurrence of the
Pram WE UN EPC Sis ia-)o siecle nes cr oS es ssn = yeincieisirslaane «oldies 302

Dates of Issue of the Quarterly Journal for 1917.

No. 289 —April 6th, 1918.

No. 290—August 20th, 1918.
No. 291—November 30th, 1918.
No. 292—December 31st, 1918.

Errata and Omissa.

Page 16, third line from the top, after the word ‘felspar,’ the following
sentence has been omitted: ‘ The laths of the ground-mass appear
to be unaltered.’

Page 53, line 25 from top, for ‘ Pl. IV, fig. 13’ read ‘ Pl. TV ines EE

Page 104, in the first column of table, jor‘ D,’ (above the words Dibuno-
phyllum 0) read ‘D,.

v

Vol. LXXIII. | No. 289.
Part 1. ;

THE

QUARTERLY JOURNAL

OF THE

[With Four Plates, illustrating Papers by Dr. A. S.
Woodward and Prof. H. H. Swinnerton & Mr, A. E. Trueman. |}

Aprit 6th, 1918.

LONDON :
LONGMANS, GREEN, AND CO.

PARIS :—CHARLES KLINCKSIBCK, 11 RUE DE LILLE.
SOLD ALSO AT THE APARTMENTS OF THE SOOINTY.

Price Five Shillings.

;
|
:
|
)

LIST OF THE OFFICERS AND COUNCIL OF THE

GEOLOGICAL SOCIETY OF LONDON.

Elected February 15th, 1918.

President.
George William Lamplugh, F.R.S.

Wice-Presivents.

R. Mountford Deeley, M.Inst.C.E.
Alfred Harker, M.A., LL.D., F.R.S.

Prof. William Johnson Sollas, M.A.,
Se.D., LL.D., F.R.S.

Sir Jethro J. Harris Teall, M.A., D.Sc.,
LL.D., F.R.S.

Secretaries.

Herbert Henry Thomas, M.A., Sc.D.

Foreign Secretary.
Sir Archibald Geikie, O.M., K.C.B., D.C.L.,
LL.D., Se.D., F.B.S.

| Herbert Lapworth, D.Sc., M.Inst.C.E.

Greasurer.
| James Vincent Elsden, D.Sc.

COUNCIL.

Charles William Andrews, D.Sc., F.R.S.

Francis Arthur Bather, M.A., D.Sc., F.RB.S.

Prof. John Cadman, C.M.G.,D.Sc., M.Inst.
C.E.

Arthur Morley Davies, D.Sc., A.R.C.Se.

R. Mountford Deeley, M.Inst.C.E.

James Vincent Elsden, D.Sc.

Prof. Edmund Johnston Garwood, M.A..,|
Sc.D., F.R.S.

Sir Archibald Geikie, O.M., K.C.B., D.C.L.,
LL.D., Sc.D., F.R.S.

John Frederick Norman Green, B.A.

Alfred Harker, M.A., LL.D., F.R.S.

Finlay Lorimer Kitchin, M.A., Ph.D.
George William Lamplugh, F.R.S.

Herbert Lapworth, D.Sc., M.Inst.C.E.

Major Henry George Lyons, D.Sc., F.R.S.

Prof. John Edward Marr, M.A., Se.D.,

F.RBS.

Richard Dixon Oldham, F.R.S.

Robert Heron Rastall, M.A.

| Prof. William Johnson Sollas, M.A.,Se.D.,
LL.D., F.B.S.

Prof. Henry Hurd Swinnerton, D.Sc.

Sir Jethro J. Harris Teall, M.A., D.Se,
LL.D., F.R.S.

Herbert Henry Thomas, M.A., Se.D.

Samuel Hazzledine Warren.

Prof. William Whitehead Watts, M.A.,
Se.D, LL.D., F.R.S.

Permanent secretary.
L. L. Belinfante, M.Sc.
Librarian.

C. P. Chatwin.
Clerk.

M. St. John Hope.
Assistant in Library.
Arthur Greig.

STANDING PUBLICATION COMMITTEE.
Mr. G. W. Lamplugh, President.

Dr. H. Lapworth.

Dr. Herbert H. Thomas.
Mr. J. F. N. Green.
Dr. F. L. Kitchin.
Major H. G. Lyons.
Mr. R. D. Oldham.

Dr. F. A. Bather.
Prof. J. Cadman.
Mr. R. M. Deeley.
Dr. J. V. Elsden.
Prof. E. J. Garwood.

} Secretaries.

Prof. W. J. Sollas.
Sir Jethro Teall.
Mr. 8S. H. Warren.
Prof. W. W. Watts.

ORDINARY MEETINGS OF THE GEOLOGICAL SOCIETY
TO BE HELD AT BURLINGTON HOUSE.

Sussion 1917-1918.

1918.
Wednesday, Amrit, ue iay we ven ben wee 17*
ss EM ai ede EN 2 gt He at 8 1—15*
: TEP S Ct 8 pean AR Si cas CRW gn og UE ONE CC 5—19*

[ Business will commence at 5.30 p.m. precisely. |
The asterisks denote the dates on which the Council will meet.

PROCEEDINGS

OF THE

}

GEOLOGICAL SOCIETY OF LONDON.

SESSION 1916-17.

f Je AF AY.
(~ MA
\
~ >.
\ A ,
® : “fp, J
™, “Hal pe
November 8th, 1916. ten, St fi

Dr. ALFRED Harxer, F.R.S., President,
in the Chair.

The List of Donations to the Library was read.

The Names of certain Fellows of the Society were read out for
the first time, in conformity with the Bye-Laws, Sect. VI, Art. 5,
in consequence of the Non-Payment of the Arrears of their
Contributions.

The PrestpEent referred to the loss which the Society had
sustained during the recess by the decease of its Treasurer,
Mr. Beprorp McNett, A.R.S.M., M.Inst.M.M., A.M.Inst.C.E.
He spoke of Mr. McNeill’s eminence in his profession, and of
the services that he had rendered to the Society as a Member of
Council for many years, and as Treasurer since 1912. The President
mentioned that the Society was well represented at the funeral,
and added that he felt sure that the Fellows would associate
themselves with the resolution of condolence and sympathy which
the Council had addressed to Mrs. McNeill.

The following communication was read :—

‘ Aulina retiformis, gen. et sp. nov., Phillipsastrea hennahi
(Lonsdale), and the Genus Orionastrea.’ By Stanley Smith,
B.A., D.Se., F.G.S.

Mr. J. W. Jackson exhibited a number of facetted pebbles
from Pendleton (Lancashire), and stated that nearly 200 of these

VOL. LXXIII. a

o> angonian

il PROCEEDINGS OF THE GEOLOGICAL SOCIETY. | vol. Ixxiil,

had been collected during the last six months from near the top of
a section of current-bedded and faulted Glacial Sand and Gravel
at an altitude of about 200 feet O.D.

The pebbles occur zz s¢tu some 2 or 3 feet below the capping of
darker subsoil, which contains cores and flakes of flint, including
pigmies. They consist of slate, granites (Eskdale and Shap),
Ennerdale granophyre, Borrowdale voleanic tuffs, porphyries,
quartzites, Millstone Grit, sandstones, Chalk flints, Carboniferous
chert, and other rocks.

The largest facetted pebble measures 113 x8 inches, and is
7 inches high; the smallest is only half an inch in diameter.

The facets are generally concave, grooved, or fluted. They vary
in number: some stones have one facet only, others two or more.
One stone with a flat top shows five incipient facets. On some
the grooving is of the nature of parallel series of elongated pits.

Differentiation. according to varying hardness and composition,
is well displayed on the granites, porphyries, grits, etc., where the
weaker constituents have been strongly eroded, leaving the stones
with an irregularly pitted surface.

The production of facets by splitting along joint-planes is seen
on some examples of sandstone; but the facet thus formed has
been modified by wind-action.

A few pebbles occurred in the sand completely inverted, and
show some distinct facetting on both sides.

Of examples orientated in sztw, the facets faced north-westwards,
westwards, and south-westwards—the directions of the present
prevailing winds.

All the pebbles are of Glacial origin, but the facetting may be
relatively quite recent. The upper part of the sands where they
occur may be the result of redistribution by wind before a soil-cap
began to form.

A series of polished specimens of Palzozoic corals was exhibited
by W. F. Gwinnell, B.Se., F.G.S.

A geological map of British Guiana, 1913 (1 : 638,600, or
1 inch=10 miles), presented by the Secretary of State for the
Colonies ; and twelve sheets of maps published and presented by
the Geological Survey of Japan, 1916 (1: 400,000), were also ex-
hibited.

Numerous books and pamphlets from the Library of R. D.
Oldham, F.R.S., V.P.G.S., were exhibited. These formed a selection
of an extensive series of publications, relating chiefly to seismology,
that Mr. Oldham recently presented to the Society.

part 1! PROCEEDINGS OF THE GEOLOGICAL SOCTETY. 11

November 22nd, 1916.

Dr. AnFreD Harker, F.R.NS., es
in the Chair.

Stanley Charles Hooper Blandford, F.S.I., Stud.Inst.M.M.,
Coronel, Chile (South America); and Herbert Kilburn Scott,
M.Inst.M.M., Jacutinga, Chesham Bois (Buckinghamshire), were
elected Fellows of the Society.

The List of Donations to the Library was read.
The following communication was read :—

‘Characee from the Lower Headon Beds.’ By Clement Reid,
F.R.S., F.L.S8., F.G.S., and James Groves, F.L.S.

The Names of certain 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 the Arrears of their
Contributions.

Lantern-slides, photographs and specimens of Characez from the
Lower Headon Beds were exhibited by Clement Reid, F.R.S..
F.L.S., F.G.8., and James Groves, F.L.S., in illustration of their
paper.

-A Paleolithic flint-implement, found in the British trenches
near Bray, was exhibited by W. Whitaker, B.A., F.R.S

A Geological sketech-map of Tasmania, based on a map by
B. M. Johnston, and revised by the Geological Survey of Tasmania
(seale: 1 nch=15 miles), 1914, was also exhibited.

A Special General Meeting was held on Wednesday, November
22nd, 1916, at 5.15 p.m. (before the Ordinary Meeting).
when James Vincent Elsden, D.Sc., was elected a Member of
Council and Treasurer in place of the late Mr. Bedford McNeill.

December 6th, 1916.

Dr. AtrreD Harker, F.R.S., President,
in the Chair.

William Ernest Hadford Burton, Wrenfield, Berlin Street,
St. John’s, Wakefield; Colin Clegg, More Hall, Bolsterstone, near
Sheffield ; William Edmund Cutler, Calgary, Alberta (Canada) ;
Hugh Peter William Giffard, B.A., B.Sc., Chillington, Wolver-
hampton; Leonard Hawkins, M.Sc., 26 Holyrood Quadrant West,
Glasgow; Daniel Franklin Higgins, M.S., care of the British Lega-
tion, Peking (China); Major John Sidney Kitson, 9 Smith Street,

a2

iv PROCEEDINGS OF THE GEOLOGICAL sociETy. [vol. xxi,

Thornbury, Melbourne (Victoria); William Pickup, President of
the Manchester Geological Society, Carlton Lea, Billinge End,
Blackburn; Lancelot Arthur Basil Sharpe, B.A., 26 St. Margaret’s
Road, Oxford ; William Walter Smithett, 34 Molyneux Park, Tun-
bridge Wells; Judge Frederic Gordon Templer, The Hall, Eagles-
cliffe, R.S.O. (County Durham); Ernest Sterne Usher, 37 Moor
Street, Fitzroy, Melbourne (Victoria); William Rupert Alfred
Weatherhead, B.Se., The University, Edmund Street, Birmingham ;
James Watt, W.S., 24 Rothesay Terrace, Edinburgh; and Edward
Walker, M.Sc., 52 (Jueen’s Road, St. John’s Wood, N.W., were
elected Fellows of the Society.

The List of Donations to the Library was read.

Mr. G. C. Crick, A.R.S.M., F.G.S., gave an account of some
recent researches on the belemnite animal. He stated
that it was not his intention to deal that evening with the
homologies of the belemnite shell or with the phylogeny of the
belemnite group, but to confine himself to the restoration of a
typical belemnite animal and its shell, as shown particularly by
examples in the British-Museum collection.

He first demonstrated, by means of a rough model, the construe-
tion of the belemnite shell, including the guard or rostrum, the
phragmocone with its ventrally- situated siphuncle, and its thin
envelope the conotheca, with its forward prolongation and expan-
sion (on the dorsal side) known as the pro-ostraeum. He then
exhibited photographie slides of examples in the British-Museum
collection showing these various characters, and noted the abrupt
termination of the chambered cone on the lower part of the pro-
ostracum, of which the dorsal surface may have been partly or
almost completely covered by a thin forward extension of the
guard. ‘To illustrate what was known of the complete body of
the animal as found associated with the guard, he then showed
photographic slides of two of the examples figured by Huxley
in his ‘Memoir on the Structure of the Belemnitide’ published in
1864. Each of these exhibited the guard associated with portions
of the pro-ostracum, the ink-bag, and the hooklets of the arms.
The form of the hooklets with their thickened bases was discussed,
this feature in a great measure justifying the attribution to the
belemnite of certain cephalopod remains (found practically at
about the same geological horizon) that included uncinated arms
associated with an ink-bag, and frequently also with nacreous
portions of (presumably) the pro-ostracum.

Of the remains of uncinated armed cephalopods from the Lias,

each exhibiting the same form of hooklets as those figured by
Huxley, he said that the British-Museum collection contained
seventeen examples, all from the neighbourhood of Lyme Regis
and of Charmouth, in Dorset. Each specimen exhibits a number of
uncinated arms associated usually with an ink-bag, sometimes also
with nacreous matter, and in two instances also with the guard or

4
:
q
i

:

part 1] © PROCEEDINGS OF THE GEOLOGICAL SOCIETY. v

rostrum. These two examples were those to which he had already
referred as having been figured by Huxley, and unfortunately
the arms are not well preserved in either of these specimens; in
one (B. bruguierianus, from the Lower Lias near Charmouth)
there are only a few scattered hooklets, while the arms of the
other (B. elongatus, from: the Lower Lias of Charmouth) are
represented only by a confused mass of hooklets. Of the other
fifteen examples, in one there are a few solitary hooklets; in
another the number of the arms is very indistinct; in two the
remains of only two arms are preserved; in one there are traces
of three arms; in two there are indications of three, or possibly
four, arms; in one there is a confused mass of possibly four
arms; and in one there are the remains of four, or possibly of five,
arms. In each of the remaining six specimens six arms can
be more or less clearly made out, while there is not a single
example in which more than six uncinated arms are displayed.

Of the six examples that exhibit six uncinated arms four are
stated to be from the Lias of Lyme Regis: one is from the Lias of
Charmouth; and one was obtained from the Lower Liassic shales
between Charmouth and Lyme Regis. From a consideration of

‘these specimens, the speaker concluded that the cephalopod repre-

sented by these uncinated arms is the animal known as the
belemnite, and that the six uncinated arms were arranged in three
pairs of unequal length, of which the longest pair was lateral, the
medium-sized pair probably dorsal, and the shortest pair probably
ventral. He considered the presence of tentacular arms to be
doubtful. These observations were in accord with those of
Huxley, who, in his ‘Memoir’ already cited, stated that he had
‘not been able to make out more than six or seven arms in
any specimen, nor has any exhibited traces of elongated tentacula,
though the shortness of the arms which have been preserved would

have led one to suspect their existence.’

The speaker regarded certain markings sometimes to be seen on
the guard as indicating that during the life of the animal the
guard was almost, if not entirely, covered by the mantle, in which
case 1t was highly unprobable that the guard was pushed into the
soft mud of the sea-bottom in order to act as an anchor.

He considered the animal to have been a free swimmer, swimming
forward ordinarily, but when desirable, capable also of sudden and
rapid propulsion backwards.

A short discussion followed, and the thanks of the Fellows
present were accorded to the Lecturer.

Lantern-slides and specimens of. belemnites were exhibited by
Mr. G. C. Crick in illustration of his lecture.

A geological map of Mysore, compiled from the Records of the
Department of Mines & Geology, Mysore (scale: 1 inch=8 miles),
1915, was also exhibited.

v1 PROCEEDINGS OF THE GEOLOGICAL Society. |{ vol. Ixxiu,

December 20th, 1916.

Dr. ALFRED Harker, F.R.S., President,
in the Chair.

The List of Donations to the Library was read.

Marie C. Stores, D.Sc., Ph.D., gave an account of some
recent researches on Mesozoic ‘Cycads’ (Bennetti-
tales), dealing particularly with recently-discovered petrified
remains which reveal their cellular tissues in microscopic prepara-
tions. ‘To make the significance of the various fossil forms clear,
the Lecturer first showed some lantern-slides of living Cycads, and
then pointed out that it was in their external features and in their
vegetative anatomy only that the fossil ‘ Cycads’ were like the
living forms: the most important features, the reproductive organs,
differ profoundly in the two groups, and the fossils were funda-
mentally distinet, not only from the living Cyeads, but from all
other living or fossil families.

The fossils representing the group that are most frequently
found are (@) trunks, generally more or less imperfect casts or
partial petrifactions, and sometimes excellent petrifactions pre-
serving anatomical details and cell-tissues ; (b) impressions of the
foliage. Not infrequent are the detached impressions of incomplete
‘flowers’ or cones, of one cohort (the Williamsonez), while
petrified fructifications are numerous in some of the well-petrified
trunks of the Bennettiteee. The described species of the group
run into hundreds, but probably many of these duplicate real
species, because the foliage, trunks, pith-casts, various portions of
the fructifications, etc., have often been separately found and
named. In very few cases have the different parts been correlated.
The species of the foliage are the most generally known, as they
are the most readily recognized with the naked eye; they have
been described under a var iety of generic names.

The. following table gives the proved, or probable, associated
parts of some members of the group :—

Foliage. Trunk. Fructifications.
Zamites spp. Bennettites spp. Bennettites spp.
Zamites gigas. Attached, no separate Williamsonia gigas.
name.
Siocaniites spl? ido es ee ee Williamsonia spectabilis.
Ptilophylluwm pectinoides. s,s. Williamsonia whitbiensis.
Anomozamites minor. (Only slender branches Wielandiella angustifolia.

known, no name.)

Teniopteris, vittatay. 6 Sac dale Williamsoniella coronata.

The Lecturer exhibited microphotographic slides of the stem
and leaf-base anatomy of the group, including some unpublished de-
tails of Bennettites maximus. The roots of the group have hitherto
been entirely unknown, and a slide was exhibited for the first time

part 1] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. vil

showing rootlets penetrating the leaf-bases of a petrified specimen
(represented by a section in the Geological Department of the
British Museum—Natural History). These roots probably belong
to Bennettites saxbyanus ; they are covered with wonderfully-
petrified root-hairs, running uncollapsed through the silica matrix.
They raise interesting questions concerning the possible chemical
conditions of the infiltration of the silica. Illustrations were also
exhibited of the famous complex ‘ flower’ and cone-structures, and
of Wieland’s brilliant restorations of the same.

Microphotographic slides were exhibited of the seed-cone of an
interesting unpublished new species from the British Gault. This
is beautifully petrified, and adds to our knowledge of the finer
anatomy of the seeds and associated structures. It is also the
largest cone of the Bennettitales yet known, though it occurs in
the Gault, by which time the group appears to have begun rapidly
to die out.

The following table illustrates the distribution of a few of the
most interesting representatives of the Bennettitales (including
the cohorts Bennettiteze and Williamsonez) :—

UFPER CRETACEOUS. Very fragmentary and uncertain records; apparently
the group is nearly or quite extinct.

MIDDLE CRETACEOUS: The new large-sized seed-cone.
Gault. B.morierei 9 (? described originally from the Jurassic).

LOWER CRETACEOUS: Well-petrified trunks with fructifications.
Lower Greensand, B. gibsonianus (type-species of the Bennettitez).

B. maximus. ) Throughout
Potton Sands. Trunks, e.g. Colymbetes edwardsi. | ane pends
‘ | in America,
Wealden. Trunks (casts and petrifactions), trunk-remains
fohage. | very abun-
B. saxbyanus. dant, often

petrified and
with fructifica-

tions, parti-
cularly from the

JuRASSIC: Purbeck. Trunks (casts and semi-petrifac- |
tions). >
Buckland’s original Cycadeoidea |

C “PP- ' Black Hills,
et O MUN. South Dakota,
Oolites. Trunks, pith-casts, etc. Much and Maryland,

foliage of various types. Wil- C. jenneyana,
liamsonia gigas and other fruit- C. ingens,
)

impressions, C. wielandt, etc.
W. scotica.
Williamsoniella coronata. Rich impressions in
Lias. Foliage and Williamsonia- Mexico of William-
: : sonia and many
fruits (India). ‘
foliage genera.
Rhetic.' Wielandiella angustifolia and foliage.

This group is by far the most characteristic of all the plants of
the Jurassic and Lower Cretaceous, during which periods its
distribution was almost world-wide. It was locally, if not univer-
sally, dominant, and was the most highly evolved plant-group of
the epoch of which we are cognizant.

Vill PROCEEDINGS OF THE GEOLOGICAL sociery. [vol. lxxiu,

Three chief points of interest are to be noted in the geological
distribution of these plants: (a) that the most numerous highly-
specialized trunks reach their maximum in the Jurassic and Lower
Cretaceous Periods, when their distribution was practically world-
wide; (6) that the oldest and therefore presumably the most
primitive type, Wvelandiella, is externally less like the living
Cycads than the commoner later forms, while these latter are
utterly unlike the living genera in their fructifications; (c) that
the geologically youngest cone is the biggest yet discovered,
occurring in the Gault when the extinction of the group appears
already to have set in.

Contrary to what might have been anticipated from their
external likeness to the living Cyecads, coupled with their great
geological age, the fossil ‘ Cycads’ are much more complex and on
a higher level of evolution than the livmg group. It seems to be
extremely unlikely that the fossil and the living forms have any
direct phylogenetic connexion nearer than a remote, unknown,
common ancestor. The mooted connexion between the fossil
‘Cycads’ and the Angiosperms is highly suggestive, but lacks
data for its establishment.

A short discussion followed, and the thanks of the Fellows
present were accorded to the Lecturer.

January 10th, 1917.

Dr. ALFRED Harker, F.R.S., President,
in the Chair.

The List of Donations to the Library was read.

The following Fellows of the Society, nominated by the Council,
were elected Auditors of the Society’s Accounts for the pre-
ceding year :—BErRNaRD Situ, M.A., and SaMUEL bE
WARREN.

The following communications were read :—

‘On the Paleozoic Platform beneath the London Basin and
ae Areas, and on the Disposition of the Mesozoic Strata
upon it.’ By Herbert Arthur Baker, B.Se., F.G.S. With an
amas by Arthur Morley Davies, D.Sc., F.G.S.

‘Balston Expedition to Peru: Report on Graptolites collected
Se Capt. J. A. Douglas, R.E., F.G.S.’. By Charles Lapworth,
LL.D., M.Sc., F.R.S., F.G.S.

Lantern-slides were exhibited by Dr. A. M. Davies, A.R.C.Sc.,
F.G.S., in illustration of Mr. H. A. Baker’s paper.

part 1] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 1X

Specimens of graptolites from the Inambari district of Peru,

collected by Capt. J. A. Douglas, were exhibited in illustration of

Prof. C. Lapworth’s paper.

A fragment of garnet-pyroxene rock, enclosing an octahedral
erystal of diamond, was exhibited by Capt. H. M. Luttman-
Johnson, R.E., F.G.S. This specimen was found in the Roberts-
Victor Mine (Orange Free State), and formed part of the larger
piece of rock described by Dr. G. 8S. Corstorphine.!

January 24th, 1917.

Dr. ALFRED Harxer, F.R.S., President,
in the Chair.

Thomas Landell-Mills, Stud. Inst.M.M., Lieut. R.E., Duke of
York’s Headquarters, Chelsea, S.W.; and John Watson, M.A.,
Bracondale, Brooklands Avenue, Cambridge, were elected Fellows

of the Society.

‘The List of Donations to the Library was read.

Dr. AuBreY Srranan, F.R.S., Director of H.M. Geological
Survey, addressing the President and Fellows, said that in 1914 a
proposal was made to subscribe for a bust of Sir Archibald
Geikie which would be presented to the Board of Education for
preservation in the Museum of Practical Geology. Notwith-
standing that war broke out shortly after the scheme was
launched, the proposal was warmly supported by geologists at
home and abroad, and among others by Fellows of the Society.
A marble bust, executed by Prof. E. Lantéri, of the Royal
College of Art, was presented to the Board on March 14th, 1916,
and placed in the Museum. At the same time a replica was
presented to Sir Archibald, who has sinve made ita gift to the
University of Edinburgh, where he was the first Murchison Pro-
fessor. The past and present staff of the Geological Survey and
Museum, thinking that a copy of the original model of the bust
would be a suitable gift to the Geological Society of London,
in whose affairs Sir Archibald had taken so prominent a part, had
caused a cast to be made, and Dr. Strahan, on their behalf,
offered it for the acceptance of the Society.

The PresipEnv, referring to Sir Archibald Geikie’s long and
intimate connexion with the Society, gratefully accepted the gift
on behalf of the Fellows.

! <The Occurrence in Kimberlite of Garnet-Pyroxene Nodules carrying
Diamonds’ Trans. Geol. Soc. S. Africa, vol. x (1907) pp. 65-68.

PROCEEDINGS OF THE GEOLOGICAL sociETy.~ | vol. Ixxiu,

ScorESBY RouriepeE, M.A., gave an account of Easter
Island. He said that the Expedition, that he had had the
honour to command, was organized with the object of carrying
out a long-standing wish of various bodies interested in anthro-
pology. “This wish was that Faster Island, and other islands
nearest to it, though far distant from it, elionha be thoroughly
examined, and that all information and material thereon found
should be carefully considered on the spot, or, if possible, be brought
back for comparative study.

This programme necessitated a vessel being specially designed,
built, and equipped for the purpose. A schooner with auxiliary
motor power, the ‘ Mana,’ of 90 tons gross register, 78 feet
on the water-line, 20 feet beam, and drawing 10°5 feet aft,
was accordingly completed by the end of 1912, and she sailed
from Southampton in February 1913 with a company of twelve
all told, of whom four formed the scientific staff. After the
longest voyage ever made by a yacht under canvas. she sailed
into Southampton again in June 1916, without having experienced
accident to man or material.

The course taken was through the Magellan Straits, and thence
through the labyrinth of Andean waterways that stretch north
therefr ‘om, and are known as the Patagonian Channels.

On reaching Juan Fernandez Island, the ‘Mana’ had to put
back to Valparaiso because the geologist of the Expedition, the
late Mr. F. L. Corry, had contracted typhoid fever on the Chilean
coast. Mr. Corry never recovered sufficiently to allow him to
rejoin the Expedition. Hence no formal geological report on
the isiand could be submitted to the Meeting. It was thought
best, therefore, to endeavour to convey the conditions existent on
Easter Island by means of a series of panoramic and other photo-
graphs, specially taken to illustrate geological features. As these
very largely consist of coast-sections, the opportunity was taken to
show, and explain, other pictures that were closely associated with
them. Such were the ruins of the village called Orongo, consisting
of peculiar canoe-shaped houses built of imbricated slabs of shale,
with the roof convex, both longitudinally and transversely, on its
exterior aspect, and covered with earth. They are romantically
situated on the rim of the voleano of Rano Kao, with an almost
sheer drop of 900 feet into the sea, or of 600 feet into the crater-
lake. At Orongo, too, are found certain large rocks, carved with
the symbol of a bird-headed man, holding in his hand an egg. A
cult, based on annually obtaining the first-laid egg of a certain
migratory sea-bird, was thus gradually brought “to hight, and
appears to be a unique form of worship. A brief outline only
could be given of some of the knowledge obtained concerning the
peculiar routine associated with seeking, and taking, the sacred
egg, and of the part which it occupied in the former religious life
of the island.

Proceeding along the coast, the Lecturer showed typical examples

part 1] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. XI

of the great terraces, and their giant stone figures, and discussed
their leading characteristics. A submarine freshwater spring, near
the great image-terrace of Tongariki, and opposite certain typical
lava-formed caves, gave occasion to the Lecturer to explain how
had arisen the longstanding, and world-wide spread report, that
man and beast on Haster Island habitually drink sea-water, in the
place of fresh.

The old voleano of Rano Raraku, the centre of the former
religious life of the island, was then described. A series of
panoramic pictures, preceded by an accurate survey made by
Lieut. R. D. Ritchie, R.N., the Cartographer of the Expedition,
showed a crater-lake surrounded by a rim of tuff which rises to a
height of 540 feet above the surrounding plain. The plain is
undulating in surface, formed superficially of hard, dense, but
nevertheless vesicular, lava, and it rests on compact non-columnar
basalt. One section of this crater-wall, some 600 yards long,
on both its interior and exterior aspects, was seen to be quarried
right up to the highest point. On the mountain-face, both inside
and out, large numbers of statues, in every state of completion,
were to be seen. The largest of these measured 68 feet in length.
Some of those excavated by the Expedition exhibited fine details,
such as the finger-nails, in perfect condition.

In conclusion, Easter Island might be described as a plateau of
basalt raised from 50 to 100 feet above the sea. Superimposed on
this were numerous cones ranging up to nearly 2000 feet. The
plateau was covered but sparsely with soil, and could only be
crossed with difficulty in any direct line. The cones, on the other
hand, were generally smooth of surface, with a good depth of soil.
Nevertheless the island is practically without trees, bushes, or

shrubs.

A short discussion followed, to which the Lecturer rephed; and
the thanks of the Fellows present were accorded to Mr. Routledge
for his lecture.

A large series of lantern-slides and specimens of the rock of
which the stone-images of Haster Island were made, were exhibited
by Scoresby Routledge, M.A.

J. B. Serivenor, M.A., F.G.S., Government Geologist to the
Federated Malay States, exhibited a manuscript geological map
of the Malay States. This map, which he presented to the Society,
was prepared by himself from all sources, and represented all that
was known of the geology of the region at the end of the year
1916.

xl PROCEEDINGS OF THE GEOLOGICAL society. [ vol. lxxii.

February 7th, 1917.

Dr. ALFRED Harxer, F.R.S., President,
in the Chair.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘The Trias of New Zealand.’ By Charles Taylor Trechmann,
M.Sc., F.G.S.

2. ‘The Triassic Crinoids from New Zealand collected by Mr. C.
T. Trechmann.’ By Francis Arthur Bather, M.A., D.Sc., F.R.S.,
F.G.S.

3. ‘On a Spilitie Facies of Lower Carboniferous Lava-Flows in
Derbyshire.’ By Henry Crunden Sargent, F.G.S.

Lantern-slides, fossils, and gutta-percha impressions of fossils
from the Trias of New Zealand were exhibited by C. T. Trechmann,
M.Sc., F.G.S., in illustration of his paper.

Lantern-slides, rock-specimens, and microscope-slides of rocks,
illustrative of the Carboniferous lava-flows in Derbyshire, were
exhibited by H. C. Sargent, F.G.S.

ANNUAL GENERAL MEETING.
February 16th, 1917.

Dr. AtFrep Harker, F.R.S., President,
in the Chair.

REPORT OF THE COUNCIL FOR 1916.

Dourine the year under review, 34 new Fellows were elected into
the Society (8 more than in 1915). Of the Fellows elected in
1916, 27 paid their Admission Fees before the end of that year,
and of the Fellows who had been elected in the previous year,
7 paid their Admission Fees in 1916, making the total accession of
new Fellows during the past year amount to 34 (3 more than in
1915).

Allowing for the loss of 66 Fellows (15 resigned, 29 deceased,
and 22 removed from the List, under Bye-Law Sect. VI, Art. 5),
it will be seen that there is a decrease of 32 in the number of
Fellows (as compared with a decrease of 59 in 1915, and an
increase of 11 in 1914).

The Total Number of Fellows is, therefore, at present 1231,
made up as follows:—Compounders 226 (7 less than in 1915);
Contributing Fellows 990 (25 less than in 1915); and Non-
Contributing Fellows 15 (the same as in 1915).

Turning now to the Lists of Foreign Members and Foreign
Correspondents, the Council has to regret the loss during the past
year of Prof. J. Gosselet, M. M. F. Mourlon, and Count H.
za Solms-Laubach. It will be remembered that, in the List of
Foreign Members at the end of 1915, there were two vacancies,
and five in that of Foreign Correspondents; and, as no elections
were held to make up the numbers during the past year, there are,
at present, four vacancies in the List of Foreign Members and six
vacancies in that of Foreign Correspondents.

The Society has to record, with deep regret, the loss during the
year of its Treasurer, Mr. Bedford McNeill, who died on Sep-
tember 18th, 1916, after holding office for 4 years. Mr. McNeill
had also served on the Council for 11 years, and the vacancy
caused by his decease was filled on November 22nd: by the election
of Dr. James Vincent Elsden as Treasurer and as a Member of the
Council.

With regard to the Income and Expenditure of the Society
during 1916, the figures set forth in detail in the Balance-Sheet
may be summarized as follows :—The actual Receipts (excluding
the Balance of £635 13s. 4d. brought forward from the previous
year) amounted to £2668 3s. ld., being £109 9s. 1d. more than
the estimated Income.

On the other hand, the Expenditure during the same year

X1V PROCEEDINGS OF THE GEOLOGICAL Society. | vol. Ixxin,

amounted to £2627 4s. Od., being £68 10s. Od. more than the
estimated Expenditure, and the year closed with a Balance in hand
of £676 12s. 5d.

On account of the special need at the present time of safe-
guarding the Society’s Archives, a strong-room has been built for
their reception ; and the existence of a particularly suitable site
in the basement of the Apartments permitted of this bemg carried
out at a comparatively low cost.

In response to the Treasury’s appeal to holders of Canadian
Securities, the Society's holding of £2000 Canadian 3% per cent.
Registered Stock, in which the Sorby and Hudleston Bequests
were invested, was deposited on loan with H.M. Government
(under Treasury Scheme B).

With regard to the publications of the Society, the Council has
to announce the completion of Vol. LXXI of the Quarterly
Journal (1915).

In accordance with the provisions of the modification of Bye-
Law Section VI, Art. 4, sanctioned at the Special General Meeting
of March 10th, 1915, the Council has. on the motion of the
Treasurer, remitted the contributions of 31 Fellows serving with
His Majesty’s Forces.

During the past year the Apartments of the Society have been
used for General and for Council Meetings by the Mineralogical
Society, the Paleontographical Society, the Ray Society, the Geo-
logical Physics Society, the Institution of Mining Engineers, the
Institution of Mining & Metallurgy, the Institution of Water
Engineers, the Institution of Municipal & County Engineers,
the Society of Engineers, and the South-Eastern Union of
Scientific Societies.

At the request of the Adyisory Council for Scientific & In-
dustrial Research, a Committee was formed to assist the Advisory
Council on matters of geological importance that might arise from
time to time. A Committee has also been formed to co-operate
with the Conjoint Board of Scientific Societies, and Dr. A. Strahan
and Prof. W. G. Fearnsides have been nominated as the Society’s
representatives on this Board.

The fourteenth Award from the Daniel Pidgeon Trust Fund
was made on April 5th, 1916, to John Kaye Charlesworth, M.Sc.,
Ph.D., who proposed to conduct researches in connexion with the
Glaciation of Donegal.

The following Awards of Medals and Funds have also been
made :—

The Wollaston Medal is awarded to Prof. Antoine Francois
Alfred Lacroix, in recognition of his ‘researches concerning the
Mineral Structure of the Earth,’ especially in connexion with the
Mineralogy and Petrology of France and her Colonies.

The Murchison Medal, together with a sum of Ten Guineas
from the Murchison Geological Fund, is awarded to Dr. George
Frederic Matthew, as an acknowledgment of his valuable work on
the Stratigraphy and Paleontology of the Lower Paleozoic Rocks
of North America.

part 1] ANNUAL REPORT. XV

The Lyell Medal, together with a sum of Twenty Pounds, is
awarded to Dr. Wheelton Hind, as anacknowledgment of the value
of his contributions to the Geology of the Carboniferous Rocks’ of
Britain, and of his researches on the Paleozoic Lamellibranchia.

The Bigsby Medal is awarded to Mr: Robert George Carruthers,
as a mark of appreciation of his work on the Carboniferous
Anthozoa and of his contributions to Scottish pearoey and to
stimulate him to further research.

The Balance of the proceeds of the Wollaston Donation Fund is
awarded to Dr. Perey George Hamnall Boswell, in recognition of
his investigations on the Tertiary and Quaternary Deposits of East
_ Anglia, and on the Petrology of the Sedimentary Rocks.

The Balance of the proceeds of the Murchison Geological Fund
is awarded to Dr. William Mackie, as an acknowledgment of his
valuable work on the Sedimentary and Igneous Rocks of Scotland,
especially in connexion’ with his researches on the Petrology and
Paleontology of the Old Red Sandstone of Elgin.

A Moiety of the Balance of the proceeds of the Lyell Geological
Fund is awarded to Dr. Arthur Hubert Cox, in recognition of the
value of his contributions to the Stratigraphy of the Lower Palzo-
zoic Rocks of South and Central Wales.

The second Moiety of the Balance of the proceeds of the Lyell
Geological Fund is awarded to Mr. Tressilian Charles Nicholas, as
an acknowledgment of his work on the Stratigraphy and Pale-
ontology of the Lower Paleozoic Rocks of North Wales.

The Balance of the proceeds of the Barlow-Jameson Fund is
awarded to Mr. Henry Dewey, in recognition of his contributions
to the Geology of the South-West of England and of his researches
in connexion with Quaternary Deposits.

Report oF THE LIBRARY COMMITTEE FOR 1916.

Much progress in the work of the Library has been made during
the year, and the number and importance of the accessions from
the usual sources are approximately the same as those of last year.
The binding of serials has been kept well in hand, and 115 separate
sheets of maps have been mounted.

A notable addition was made during the recess in the form of
numerous volumes and pamphlets presented by Mr. R. D. Oldham,
F.R.S. The series obtained from Mr. Oldham’s Library is parti-
eularly rich in seismological literature, and three serials in this
branch are new to the Society’s Library; they are the Publications
of the Japanese Earthquake Committee in Foreign Languages, the
Bulletins of the Imperial Earthquake Investigation Committee, and
the Bollettino della Societa Sismologica Itahana. ‘Two other serials
were presented—the Annual Reports of the Cape of Good Hope
Geological Commission from its commencement until 1911, anda
complete set of the publications of the Société de Spéléologie,
Paris; the former is a valuable addition on account of its rarity,

XVl PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ vol. xxiii,

and the latter on account of its being the only complete set now
in a London Library. In all 91 Volumes of serials have been
added.

Thirty-nine Volumes of separately-published works were also
chosen from Mr. Oldham’s Library ; most of them were new to the
Society’s collection, but certain duplicates were selected on account
. of their use for purposes of circulation. 7

A series of pamphlets, reports and extracts (numbering alto-
gether 156 works) forms an important part of this new addition.
Indian geology is represented in this section by 45 publications,
several rare reports being included. There are 47 papers on
Earthquakes, 32 on Permian Glaciation, 9 on Petrology, and 7 on
Paleobotany, the remaining 16 being of a miscellaneous character.
Included also in Mr. Oldham’s donation are seismograms of the
North Pacific and South American Earthquake of August 16th,
1906 (published by the International Seismological Association)
and an Album of Photographs of the Gohna Landslip of 1894. .

Donations from other sources number 18 Volumes of separately-
published works, 184 Pamphlets, and 2 detached Parts of works,
also 124 Volumes and 386 detached Parts of serial publications,
44 Volumes and 123 detached Parts of the publications of Geo-
logical Surveys and other public bodies, and 8 Volumes of weekly
periodicals.

The total number of accessions by Donation amounts, therefore,
to 324 Volumes, 340 Pamphlets, and 509 detached Parts.

Among the books and pamphlets mentioned in the foregoing
paragraph, especial attention may be drawn to the following
works :—‘ The Subantarctic Islands of New Zealand: Reports on
the Geo-Physics, Geology, &c.,’ 2 vols., edited by C. Chilton
(Philosophical Institute of Canterbury, New Zealand), 1909;
‘ Fossil Vertebrates in the American Museum of Natural History
—Department of Vertebrate Paleontology,’ vol. iv (1915) and
vol. v (1916), by H. F. Osborn and others; ‘The Geology of
the English Lake District,’ by J. E. Marr, 1916; ‘The Topo-
graphy & Geology of West Central Sinai,” by John Ball
(Ministry of Finance, Survey Department of Egypt), 1916; ‘A
Bibliography of Yorkshire Geology,’ by T. Sheppard (C. Fox-
Strangways Memorial Volume—Proe. Yorks. Geol. Soc. vol. xvii,
1915) ; ‘ Papers from the Geological Department, Glasgow Uni-
versity,’ vol. ii (1915), 1916; the third edition of the ‘ Data of
Geochemistry, by F. W. Clarke (Bulletin of the United States
Geological Survey, No. 616, 1916); Ricerche Idrogeologiche,
Botaniche, &c., fatte nella Somalia Italiana Meridionale, 1913’
(Missione Stephanini- Paoli — Relazioni & Monografie Agraria-
Coloniali, No. 7, 1916); 6 parts of the ‘Mémoires du Service
Géologique de l’Indochine,’ dealing with the stratigraphy and
paleontology of that region; and, among the publications of the
Geological Survey of England and Wales, the volume on the
Thicknesses of Strata and five volumes of Special Reports on
the Mineral Resources of Great Britain.

An extensive series of works has also been received from the

part 1] | - - ANNUAL REPORT. XVil

United States Geological Survey; and the Geological Survey of
Canada has presented a number of memoirs of economic
importance.

Numerous Colonial Office Reports have been presented through
the kindness of Mr. J. F. N. Green, and it has thus been found
possible to complete certain sets of these’ publications in the
Society’s Library. A series of reports relating to the Mineral
Survey of Ceylon has also been presented by Dr. A. K.
Coomaraswamy.

A decrease in the number of new Maps received is again to be
noted; but this year 12 sheets have been received from the Geo-
logical Survey of Japan, 2 from that of New South Wales, 2 from
that of Scotland, and one each from British Guiana, Mysore, Nor-
way, Tasmania, and Tennessee.

The Donors during the preceding year included 99 Government
Departments and other Public Bodies, 103 Societies and Editors
of Periodicals, and 113 Personal Donors.

The Purchases included 38 Volumes and 7 detached Parts of
separately published works, and 6 Volumes and 384 detached Parts
of works published serially.

The Expenditure incurred in connexion with the Library during
the year under review was as follows :—

ces. a

Seeteeemerrenonials. |... 6.c.2i.....c esc ceeeeen. VL. 7 8
Binding and Map-mounting ..................... 65 38 11
rearosmte Cabinets... ...... 22.0556... cdee eee see te a7, 16-0
Seeds A yi, Sees Lr 38
atailetatieies.... clon, LOLLO

Work on the cataloguing and indexing of the accessions of 1918
has been well advanced, and good progress has been made with
No. 20 of the ‘ Record of Geological Literature.’

With reference to the Card-Catalogue of the Library, a slip was
issued with No.*283 of the Quarterly Journal (September 1916),
setting forth the progress of Mr. Sherborn’s work. When the
task of editing the existing material has been accomplished, the
Catalogue will be practically complete from the year 1800 to 1912;
while it contains a large number of entries relating to previous
years. The Catalogue includes over a million entries to which
reference can be made, and is now contained in 540 drawers of
cards under one alphabetical arrangement of authors, subjects, and
localities. The recent publication by the Cambridge University
Press of the fifteenth volume of the Royal Society's Catalogue of
Scientific Literature will entail many further additions to the Card-
Catalogue. This new volume ranges from FITTING to HYSLOP, and
Mr. Sherborn is now engaged on the selection of the geological
papers, the transference to cards, and the indexing and incorporation
of the titles, etc. of those papers.

VOL. LXXIII. b

XVili PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [/vol. Ixxiii,

The appended Lists contain the Names of Government Depart-
ments, Public Bodies, Societies, Editors, and Personal Donors, ee
whom Donations to the Library have been received during the year
under review :— c

I. GOVERNMENT DEPARTMENTS AND OTHER Pustic Bopigs.

American Museum of Natural History. New York.

Australia (S.), etc. See South Australia, ete.

Bergens Museum. Bergen.

Birmingham, University of.

British Columbia.—Department of Mines. Victoria (B.C.).
British Guiana.—Department of Mines. Georgetown.

Buenos Aires.—Museo Nacional de Buenos Aires.
Californsa.—Academy of Sciences. San Francisco.

—., University of. Berkeley (Cal.).

Camborne.—Mining School. :
Cambridge (Mass.).—Museum of Comparative Zoology in Harvard College.
Canada.—Department of Mines. Ottawa.

, High Commissioner for. London.

Cape of Good Hope——South African Museum. Cape Town.
Chicago.—‘ Field’ Columbian Museum.

Connectieut.—State Geological & Natural History Survey. Hartford (Conn.).
Cérdoba (Argentine Republic).—Academia Nacional de Ciencias.
Denmark.—Geologiske Underségelse. Copenhagen.

. Kongelige Danske Videnskabernes Selskab. Copenhagen.
Dublin.—Royal Irish Academy.

Egypt.—Deparcment of Public Works (Survey Department). Cairo.
Great Britain.—British Museum (Natural History). London.
—. Colonial Office. London.

—. Geological Survey. London.

—. Home Office. London.

Holland.—Rijksopsporing van Delfstoffen. The Hague.
Hull—Municipal Museum.

Illinois State Geological Survey. Urbana (IIl.).
India.—Geological Survey. Calcutta.

—. Surveyor-General’s Office. Calcutta.

Iowa Geological Survey. Des Moines (Iowa).
Treland.—Department of Agriculture & Technical Instruction. Dublin.
Italy.— Reale Cumitato Geologico. Rome.
Japan.—Earthquake-Investigation Committee. Tokyo.
Geological Survey. ‘Tokyo.

Kingston (Canada).—Queen’s College.

Leeds, University of.

London.—City of London College.

Imperial College of Science & Technology.

—. Imperial Institute.

—. Metropolitan Water Board.

—. Royal College of Surgeons.

University College.

Madrid.—Real Academia de Ciencias Exactas, Fisicas & Naturales.
Melbourne (Victoria) —National Museum.

Mexico.—Instituto Geolégico. Mexico City.

Milan.—Reale Istituto Lombardo di Scienze & Lettere.

New Jersey.—Geological Survey. Trentham (N.J.).

New South Wales, Agent-General for. London.

Department of Mines & Agriculture. Sydney.

. Geological Survey. Sydney.

New York State Museum. Albany (N.Y.).

New Zealand.—Department of Mines. Wellington.

Geological Survey. Wellington.

Norway.—Norges Geologiske Undersékelse. Christiania.

Nova Scotia.—Department of Mines. Halifax.

Ohio Geological Survey. Columbus (Ohio).

Oklahoma Geological Survey. Norman (Okla.).

.
'
:

part 1] ANNUAL REPORT. xix

Ontario.—Bureau of Mines. Toronto.

Padua.—Reale Accademia di Scienze, Lettere & Arti.

——, Royal University of.

Paris.—Académie des Sciences.

Peru.—Ministerio de Fomento. Lima.

Philippine Is.—Department of the Interior: Bureau of Science. Manila.
Pisa, Royal University of.

Portugal.—Commissao dos Trabalhos Geologicos. Lisbon.

Queensland, Agent-General for. London.

. Department of Mines. Brisbane.

——. Geological Survey. Brisbane.

Redruth.—School of Mines.

Rio-de Janeiro.—Museu Nacional.

Rome.—Reale Accademia dei Lincei.

Russia.—Comité Géologique. Petrograd.

Musée Géologique Pierre le Grand. Petrograd.

—. Section Géologique du Cabinet de S.M. ’?Empereur. Petrograd.
Sao Paulo (Brazil)—Commissao Geographica & Geologica. Sfo Paulo City.

—. Secretaria da Agricultura, Commercio & Obras Publicas. Sao Paulo City.

Senda? (Japan).—Tohoku Imperial University.

South Africa, Union of.—Departiment of Mines. Pretoria
South Australia, Agent-General for. London.

—. Department of Mines. Adelaide.

——. Geological Survey. Adelaide.

Stockholm.—Kongliga Svenska Vetenskaps Akademi.
Sweden.—Sveriges Geologiska Undersdkning. Stockholm.
Switzerland.—Geologische Kommission der Schweiz. Berne.
Tasmania.—Secretary for Mines. Hobart.

Tokyo.—College of Science (Imperial University).
Turin.—Reale Accademia delle Scienze.

Union of South Africa. See South Africa.

United States.—Department of Agriculture. Washington (D.C.).
—. Geological Survey. Washington ().C.).

—. National Museum. Washington (D.C.).

Upsala, Royal University of.

Victoria (Austral.), Agent-General for. London.
Department of Mines. Melbourne.

). Geological Survey. Melbourne.

Washington (D.C.).—Smithsonian Institution.

Washington, State of (U.S.A.).—Geological Survey. Olympic (Wash.).
Western Australia, Agent-General for. London.

—. Department of Mines. Perth.

——. Geological Survey. Perth.

—

Il. Socterres anp EprTors.

Adelaide.—Royal Society of South Australia.
Basel.—Naturforschende Gesellschaft.

Bergen.—‘ Naturen.’

Berne.—Schweizerische Naturforschende Gesellschaft.

Boston (Mass.).—American Academy of Arts & Sciences.

Bristol Naturalists’ Society.

Buenos Aires.—Sociedad Cientifica Argentina.
_Calcutta.—Asiatic Society of Bengal.

Cambridge Philosophical Society.

Cape Town.—Royal Society of South Africa.
South African Association for the Advancement of Science.
Cardiff—South Wales Institute of Engineers,

Chicago.—‘ Journal of Geology.’

Christiania.—‘Nyt Magazin for Naturvidenskaberne.’

Croydon Natural History & Scientific Society.

Dorchester.—Dorset Natural History & Antiquarian Field-Club.

Dorpat (Jurjew).—Naturforschende Gesellschaft.
- Edinburgh.—Geological Society.

—. Royal Scottish Geographical Society.

—. Royal Society. —

b2

Orde

PROCEEDINGS OF THE GEOLOGICAL SOCIETY. (vol. lxxin,

Ekaterinburg.—Société Ouralienne d’Amateurs des Sciences Naturelles
Falmouth.—Royal Cornwall Polytechnic Society. bie
Geneva.—Société de Physique & d’ Histoire Naturelle.
Glasgow.—Geological Society.

Gloucester.—Cotteswold Naturalists’ Field-Club.
Hereford.—Woolhope Naturalists’ Field-Club.
Hertford.— Hertfordshire Natural History Society.

Hull Geological Society.

Johannesburg.—Geological Society of South Africa.
Kiev.—Société des Naturalistes.

Lancaster (Pa.).—* Economic Geology.’
Leeds.—Yorkshire Geological Society.

Leicester Literary & Philosophical Society.

Lima.—‘ Revista de Ciencias.’ =
Lisbon.—Sociedade de Geographia.

Société Portugaise des Sciences Naturelles.
Liverpool Geological Society.

Literary & Philosophical Society.
London.—British Association for the Advancement of Science.
Chemical Society.

‘The Chemical News.’

‘The Colliery Guardian.’

‘The Geological Magazine.’

Geologists’ Association.

Institution of Civil Engineers.

Institution of Mining Engineers.

Institution of Mining & Metallurgy.

Institution of Water Engineers.

Iron & Steel Institute.

Linnean Society.

‘The London, Edinburgh, & Dublin Philosophical Magazine.’
Mineralogical Society.

‘Nature.’

Paleontographical Society.

Prehistoric Society of East Anglia.

‘The Quarry.’

Royal Geographical Society.

Royal Institution.

Royal Meteorological Society.

Royal Microscopical Society.

Royal Photographic Society.

Royal Society.

Royal Society of Arts.

Victoria Institute.

‘ Water.’

. Zoological Society.

Manchester Geological & Mining Society.

Literary & Philosophical Society.

Melbourne (Victoria) —Australasian Institute of Mining Engineers.
Royal Society of Victoria.

‘The Victorian Naturalist.’

Mexico.—Sociedad Cientifica ‘ Antonio Alzate.’

Moscow.—Société Impériale des Naturalistes.

WEPEEEEEEET TIT TT 14

Newcastle-upon-Tyne.—North of England Institute of Mining & Mechanioal

Engineers.

University of Durham Philosophical Society.
New Haven (Conn.).—Academy of Arts & Sciences.

‘The American Journal of Science.’

New York.—Academy of Sciences.
—. American Institute of Mining Engineers.
‘ Science.’
Northampton.—Northamptonshire Natural History Society.
Oporto.—Academia Polytecnica. {Coimbra.]
Ottawa.—Royal Society of Canada.
Perth.—Perthshire Society of Natural Science.
Philadelphia.—Academy of Natural Sciences.

‘The South-Eastern Naturalist’ (S.E. Union of Scientific Societies). |

ee se

Pare ANNUAL REPORT. ~ fig xxl

Philadelphia.—American Philosophical Society.
Plymouth.—Devonshire Association for the Advancement of Science.
Rochester (N.Y.).—Academy of Science.

-——. Geological Society of America.
Rome.—Societa Geologica Italiana.
Rugby School Natural History Society.

Stockholm.—Geologiska Férening.
Stratford.—Essex Field-Club.
Sydney (N.S.W.).—Linnean Society. of New South Wales.

Royal Society. of New South Wales...

Toronto.—Canadian Institute.
Truro.—Royal Institution of Cornwall.
Washington (D.C.).—Academy of Sciences.
—. Philosophical Society.

Wellington (N.Z.).—New Zealand Institute.

Worcester.— Worcestershire Naturalists’ Club.

York.—Yorkshire ee Society.

Abbott, G.
Allen, LH. A.
Ameghino, C.
Andrews, E. C.

Ball, J.

Barrell, J.
Batchelor, E.
Becker, G. F.
Bonney, T. G.
Boswell, P. G. H.
Bowen, N. L.

Cate, D. H. S. Blaupot
ten-.

Chapman, F.

Chirvinski, P. N.

Choffat, P

Cole, G. A. J.

Collins, J. H.

Coomaraswamy, A. K.

Cope, Mrs. T. H.

Craig, E. H. C.

Crick, G. C.

Cumings, E. R.

Dall, W. H:~
Daly, R. A.
Davies, G. M.
Day, A. L.
Dewey, H.
Dupare, L.

Ellis, T. S.
Evans, O. H.

Fearnsides, W. G.
Filliozat, M.
Fleury, E
Fourtau, R.
Foye, W. G.

Gadeceau, K.
Galloway, J. J.
Geikie, Sir Archibald.

Green, J. F. N.
Gregorio, A. de.
Gregory, J. W.
Grosset, A.
Gurley, R. R.

Heim, Albert.
Heim, Arnold.
Henderson, J. A. L.
Holst, N. O
Hopkinson, J.
Horne, J.

Hughes, T. McK.
Hume, W. F. |

Jack, R.L.
Jackson, J. W.
Johnston, J.
Jones, W. R.
Knight, C. W.

Leach, A. L.

_. Leucewicz, S.
Lewinson-Lessing, F.

Lomax, J.
Lugeon, M.
Lyons, H. G.

Marr, J. E.
Martin, KE. A.

|. Merwin, H. E.

Miller, W. G.
Monckton, H. W.

Newton, E. T.
Newton, KR. B.
Nicholas, R. E.
North, F. J.

Odling, M.
Osborn, H. F.

Palmer, H. S.

LEE Sa eren Donors.

Percival, F. G.
Pickering, A. J.
Preller, C.S. Du R.
Purington, C. W.

Reid, C.
Reusch, H.
Richards, H. C.

Sabot, R. C.
Sauvage, H. E.
Sawyer, A. R.
Schardt, H.
Schuchert, C.
Schwarz, E. H. L.
Sheppard, T.
Sherborn, C. D.
Smith, B.

Smith, R. A.
Smith, 8.
Sosman, R. B.
Stebbing, W. P. D.
Stevenson, J. J.
Stobbs, J. T.
Stoyanov, A.
Strahan, A.

Thompson, B.
Titanovich, M.
Tse Tsan T'ai.
Tyrrell, G. W.
Tyrrell, J. B.

Vasiliev, V. T.
Vaughan, T. W.
Veatch, A. C.

Washington, H. S.
Wherry, E. T.
Whitaker, W.
Wills, L. J.
Woodward, H.
Wray, D. A.
Wright, F. E.

xxii PROCEEDINGS OF THE GEOLOGICAL society. [ vol. lxxiu,

CoMPARATIVE STATEMENT OF THE NUMBER OF THE SOCIETY AT
THE CLOSE OF THE YEARS 1915 ann 1916.

Dec. 31st, 1915. Dec. 31st, 1916.
Compounders .......0..3. 00020 Zac > ase 223
Contributing Fellows......... 1009 * ~~. eee 990
Non-Contributing Fellows... 15°. hae 15
1257 1228
Foreign Members ............ Of -* tae 36
Foreign Correspondents...... 39°) 38
1333 1302

Comparative Statement, explanatory of the Alterations in the
Number of Fellows, Foreign Members, and Foreign Correspon-
dents at the close of the Years 1915 and 1916.

Number of Compounders, Contributing, and Non- 1257
Contributing Fellows, December 31st, 1915..

Add Fellows elected during the former meee aiid -
paid in 1916.. os
Add Fellows aoa i aid dr In £916 - 332. 24
Add Fellows reinstated after payment of arrears. 3
1294
Deduct Compounders deceased ............42.2... 10
Contributing Fellows deceased _.............. 19
Contributing Fellows resigned ............4.. 15
Contributing Fellows removed ............4 22
— 66
1228
Number of Foreign Members and Foreign Cor- 76
respondents, December 31st, 1915 ...............
Deduct Foreign Member deceased .. osha
Deduct Foreign Correspondent deceased ......... 1
74
— 74
1302

te
~

part 1]

ANNUAL REPORT.

XXI11

DECEASED FELLOWS.

Compounders (10).

Barnett, A. K. [elected 1875. |
Clough, C. T. [el. 1875. ]
Derby, O. H. [el. 1884. ]
Deverell, L. C. [el. 1901. ]
Don, A. W. R. [el. 1912. ]

Meade, T. de Courcy [el. 1891. ]
Peyton, J. HE. H. [el. 1871.]
Reid, Clement [el. 1875. ]
Ross, W. J. C. [el. 1882. |
Stone, Sir John B. [el. 1864. |

Resident and other Contributing Fellows (19).

Allen, G. A. [elected 1904. |
Collins, J. H. [el. 1869. ]
Croom-Johnson, A. [el. 1911. ]
Dunlop, A. [el. 1874. ]
Dawson, C. [el. 1885. ]
Fairley, W. [el. 1887. |
Florence, H. L. [el. 1872. |
Fowler, G. H. [el. 1904. ]

- Hawtrey, R. [el. 1912.]
Holiday, F. A. [el. 1910. ]

Judd, J. W. [el. 1865. ]

Koch, W. E. [el. 1869. ]
Lewer, R. R. [el. 1911.]
McNeill, B. [el. 1888. |
Power, E. J. [el. 1898. |
Simpson, J. C. [el. 1906. |
Swann, J. S. [el. 1865. |
Wardell, S. C. [el. 1880. ]
Woodall, Sir Corbet [el. 1884. |

FELLows REsIGNeED (15).

André, G. G.
Banbery, E. C.
Broad, W.

Butler, G. G.
Childe, H. S.
Coleman, C. J. :
De Muller, W. J. E.
Gasking, S.

Hay, J. D.

Henderson, J. M‘C.
Powney, W. E. F.
Rolfe, W.

Szlumper, Sir James W.

| Walker, W. P.
Watermeyer, T. H.

XXIV. PROCEEDINGS OF THE GEOLOGICAL society. | vol. lxxin,

FELLows REMOVED (22).

Binet, E. P. ts Krausé, H. L.
Briggs, H. Miller, F. R. L.
Crankshaw, J. Perkes, S.
Croston, J. W. Poole, W.
Waniel (Pk. Preston, F. M.
Davies, J. Prouse, O. M.’
Davies, W. H. Rawlins, C. C.
Eastaugh, F. A. Temby, E. T.
Hosking, J. H. Zeller, C. van.
Jorissen, E. | +8 reinstated. |

ForEIGN MEMBER DECEASED.
Prof. Jules Gosselet.

FOREIGN CORRESPONDENT DECEASED.
M. Michel F. Mourlon.

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 Thomas
Holland and the Rev. H. H. Winwood, retiring from the office
of Vice-President and also from the Council, and to the other
retiring members of the Council: Mr! H. Bury, Prof. W. G. Fearn-
sides, and Mr. W. Whitaker.

After the?[Balloting-Glasses had been 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 :—

part 1] | ee OMNI ASR PORT: XXV.

OFFICERS AND COUNCIL.—1917.

PRESIDENT.
Alfred Harker, M.A., LL.D., F.R.S.

VICE-PRESIDENTS.

R. Mountford Deeley, M.Inst.C.E.

Edwin Tulley Newton, F.R.S.

Prof. William Johnson Sollas, M.A., LL.D., Sc.D., F.R.S.
Arthur Smith Woodward, LL.D., F.R.S., F.L:S.

SECRETARIES.
Herbert Henry Thomas, M.A., Sc.D.
Herbert Lapworth, D.Sc., M.Inst.C.H.
FOREIGN SECRETARY. |
Sir Archibald Geikie, O.M., K.C.B., D.C.L., LL.D., Se.D.,
E.R.S.
TREASURER.
James Vincent Elsden, D.Se.

COUNCIL.
Charles William Andrews, D.Sc., | Herbert Lapworth, D.Sc., M.Inst.
ERS. evr Gee.

Prof. John Cadman, C.M.G., D.Sc. || John Edward Marr, Se.D., F.R.S.
Prof. Charles Gilbert Cullis, D.Sc. | Edwin Tulley Newton, F.R.S.
Arthur Morley Davies, D.Sc. Richard Dixon Oldham, F.R.S.

Rt. Mountford Deeley, M.Inst.C.E. || Robert Heron Rastall, M.A.

Prof. Hdmund Johnston Garwood, | Prof. Thomas Franklin Sibly, D.Sc.

M.A., Se.D., F.B.S. Prof. William Johnson Sollas, Se.D.,
Sir Archibald Geikie, O.M., K.C.B., Mh De RRS:

Peer. O1:D., Se.D., F.B:S. Sir Jethro J. Harris Teall, M.A.,
Walcot Gibson, D.Sc. D:Se,-bLiD., ERS:

Alfred Harker, M.A., LL.D., F.R.S. || Herbert Henry Thomas, M.A., Sc.D.
Finlay Lorimer Kitchin, M.A., || Samuel Hazzledine Warren.

Ph.D. Arthur Smith Woodward, LL.D.,
George William Lamplugh, F.R.S. F.R.S., F.L.S.

XXVi

PROCEEDINGS )F THE GEOLOGICAL socreTY. [vol. lxxin,

LIST OF

THE FOREIGN MEMBERS

OF THE GEOLOGICAL SOCIETY OF LONDON, 1 1916.

Date of
Election.

1884.
1886,
1891.
1898.
1893.
1894.
1895.
1896,
1897.
1898.
1899.
1899.
1900.
1900.
1900.
1901.
1901.
1903.
1903.
1904.
1904.
1905.
1908.
1907.
1907.
1908.
1909.
1911.
1911.
1912.
1913.
1914,
1914.
1914,
1914.
1914.

Commendatore Prof. Giovanni Capellini, Bologna.

Prof: Gustav Tschermak, Vienna.

Prof. Charles Barrois, Lille.

Prof. Waldemar Christofer Brégger, Christianta.

Prof. Alfred Gabriel Nathorst, Stockholm.

Prof. Edward Salisbury Dana, New Haven, Conn. (*.S.A.).
Dr. Grove Karl Gilbert, Washington, D.C. (U.S.A.).

Prof. Albert Heim, Ziirich.

Dr. Hans Reusch, Christiania.

Dr. Charles Doolittle Walcott, Washington, D.C. (U.S.A.).
Prof. Emanuel Kayser, Marburg.

M. Ernest Van den Broeck, Brussels.

M. Gustave F. Dollfus, Pars.

Prof. Paul von Groth, Munich.

Dr. Sven Leonhard Tornquist, Lund.

M. Alexander Petrovich Karpinsky, Petrograd.

Prof. Antoine Francois Alfred Lacroix, Paris.

Prof. Albrecht Penck, Berlin.

Prof. Anton Koch, Budapest.

Prof. Joseph Paxson Iddings, Brinklow, Maryland (U.S.A.).
Prof. Henry Fairfield Osborn, New York (U.S.A.).
Prof. Louis Dollo, Brussels.

Prof. August Rothpletz, Munich.

Hofrath Dr. Emil Ernst August Tietze, Vienna.
Commendatore Prof. Arturo Issel, Genoa.

Prof. Bundjiré Kot6, Tokyo.

Prof. Johan H. L. Vogt, Christiania.

Prof. Baron Gerard Jakob de Geer, Stockholm.

M. Emmanuel de Margerie, Paris.

Prof. Marcellin Boule, Paris.

Prof. Johannes Walther, Halle an der Saale.

Prof. Friedrich Johann Becke, Vienna.

Prof. Thomas Chrowder Chamberlin, Chicago, Ill. (U.S.A.).
Prof. Franz Julius Loewinson-Lessing, Petrograd.

Prof. Alexis Petrovich Pavlow, Moscow.

Prof. William Berryman Scott, Princeton (New Jersey).

part 1] ANNUAL REPORT. XXVil

LIST OF

THE FOREIGN CORRESPONDENTS

OF THE GEOLOGICAL SOCIETY OF LONDON, rw 1916.

Date of
Election.

1879. Dr. H. Emile Sauvage, Boulogne-sur-Mer. ( Deceased.)
1889. Dr. Rogier Diederik Marius Verbeek, The Hague.

1890. Geheimer Bergrath Prof. Adolph von Koenen, Gottingen.
1892. Prof. Johann Lehmann, Weimar.

1894. Dr. Francisco P. Moreno, La Plata.

1898. Dr. W. H. Dall, Washington, D.C. (U.S.A.).

1899. Dr. Gerhard Holm, Stockholm.

1899. Prof. Theodor Liebisch, Berlin.

1900. Prof. Federico Sacco, Turin.

1902. Dr. Thorvaldr Thoroddsen, Copenhagen.

1902. Prof. Samuel Wendell Williston, Chicago, Ill. (U.S.A.).

1904. Dr. William Bullock Clark, Baltimore (U.S.A.). (Deceased.)
1904, Dr. Erich Dagobert yon Drygalski, Charlottenbury.

1904. Prof. Giuseppe de Lorenzo, Naples.

1904. The Hon. Frank Springer, Last Las Vegas, New Mexico (U.S.A.)
1904. Dr. Henry Stephens Washington, Washington, D.C. (U.S.A.).
1906. Prof. John M. Clarke, Albany, N.Y. (U.S.A.).

1906. Prof. William Morris Davis, Cambridge, Mass. (U.S,A.).
1906. Dr. Jakob Johannes Sederholm, Helsingfor's.

1908. Prof. Hans Schardt, Ziirich.

1909. Dr. Daniel de Cortaézar, Madrid.

1909. Prof. Maurice Lugeon, Lausanne.

1911. Prof. Arvid Gustaf Hégbom, Upsala.

1911. Prof. Charles Depéret, Lyons.

1912. Dr. Frank Wigglesworth Clarke, Washington, D.C. ( U.S.A.)
1912. Dr. Whitman Cross, Washington, D.C. (U.S.A.).

1912. Baron Ferencz Nopesa, Temesmegye (Hungary).

1912. Prof. Karl Diener, Vienna.

1912. Prof. Fusakichi Omori, Tokyo.

1912. Prof. Ernst Weinschenk, Munich.

1913. Dr. Emile Haug, Paris.

1913. Dr. Per Johan Holmquist, Stockholm.

1914. Dr. Paul Choffat, Lisbon.

1914. Dr. Charles Richard Van Hise, Madison, Wisconsin (U.S. A.).

XXVlil PROCEEDINGS OF THE GEOLOGICAL sociEery. [ vol. Ixxiu,

AWARDS OF THE WOLLASTON MEDAL
UNDER THE CONDITIONS OF THE ‘ DONATION FUND’

ESTABLISHED BY

WILLIAM HYDE WOLLASTON, M.D., F.RS., ¥.G.8., mre.

‘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. ~ 1874. Prof. Oswald Heer.
1835. Dr. Gideon A. Mantell. 1875. Prof. L. G. de Koninck.
1886. M. Louis Agassiz. 1876. Prof. Thomas H. Huxley.
1887 pet T. P. Cautley. 1877. Mr. Robert Mallet.
* ) Dr. Hugh Falconer. 1878. Dr. Thomas Wright.
1838. Sir Richard Owen. 1879. Prof. Bernhard Studer.
1839. Prof. C. G. Ehrenberg. 1880. Prof. Auguste Daubrée.
1840, Prof. A. H. Dumont. 1881]. Prof. P. Martin Dunean.
1841. M. Adolphe T. Brongniart. 1882. Dr. Franz Ritter von Hauer.
1842. Baron Leopold von Buch. | 1888. Dr. William T. Blanford.
, JM. Elie de Beaumont. 1884. Prof. Albert Jean Gaudry.
1843. 1M P. A. Dufrénoy. 1885. Mr. George Busk.
1844. The Rev. W. D. Conybeare. | 1886. Prof. A. L. O. Descloizeaux.
1845. Prof. John Phillips. | 1887. Mr. John Whitaker Hulke.
1846. Mr. William Lonsdale. 1888. Mr. Henry B. Medlicott.
1847. Dr. Ami Boué. | 1889. Prof.Thomas George Bonney.
1848. The Very Rev. W. Buckland. | 1890. Prof. W. C. Williamson.
1849, Sir Joseph Prestwich. — 1891. Prof. John Wesley Judd.
1850, Mr. William Hopkins. | 1892. Baron F. von Richthofen.
1851. The Rev. Prof. A. Sedgwick. | 1893. Prof. Nevil Story Maskelyne.
1852, Dr. W. H. Fitton. | 1894. Prof.Karl Alfred von Zittel.
1853 1 M.le Vicomte A.d’Archiac. | 1895. Sir Archibald Geikie.

*) M. E. de Verneuil. | 1896. Prof. Eduard Suess.

1854. Sir Richard Griffith. 1897. Mr. Wilfrid H. Hudleston.
1855. Sir Henry De la Beche. _ 1898. Prof. Ferdinand Zirkel.
1856. Sir William Logan. 1899. Prof. Charles Lapworth.
1857. M. Joachim Barrande. ~ 1900. Dr. Grove Karl Gilbert.
1858 oe Hermann von Meyer. 1901. Prof. Charles Barrois.

’ ) Prof. James Hall. 1902. Dr. Friedrich Schmidt.
1859. Mr. Charles Darwin. 1903. Prof. Heinrich Rosenbuscb.
1860. My. Searles V. Wood. 1904. Prof. Albert Heim.

L861." Prof. Dr. F-G2Bronn. 1905. Sir Jethro J. H. Teall.
1862. Mr. R. A. C.Godwin-Austen, | 1906. Dr. Henry Woodward.
1863. Prof. Gustav Bischof. - 1907. Prof. William J. Sollas.
1864. Sir Roderick Murchison. 1908. Prof. Paul von Groth.

1865. Dr. Thomas Davidson. 1909. My. Horace B. Woodward.
1866. Sir Charles Lyell. 1910. Prof. William B. Scott. .:
1867. Mr. G. Poulett Scrope. 1911. Prof. Waldemar C. Brogger.
1868. Prof. Carl F. Naumann. 1912. Sir Lazarus Fletcher.

1869. Dr. Henry C. Sorby. 1913. The Rey. Osmond Fisher.
1870. Prof. G. P. Deshayes. 1914. Prof. John Edward Marr.
1871. Sir Andrew Ramsay. 1915. Prof.T.W.Edgeworth David.
1872. Prof. James D). Dana. 1916, Dr. A. P. Karpinsky.

1873. Sir P. de M. Grey Egerton. 1917. Prof. A. F. A. Lacroix.

‘aré1] ~° -

1831.
1833.
1884.
1835:
1836.
1838.
1839.
1840.
1841,
1842.
1843.
1844.
1845,
1846,
1847.
1848,

1849.
1850.
1851.
1852.
1853.
1854.

1855.

1856.
1857.
1858.
1859.

1860.

1861.
1862.
1863.
1864.
1865.
1866.
1867.
1868.
1869,
1870.

1871

1872.
1873.

AWARDS

ANNUAL REPORT.

OF THE

BALANCE OF THE PROCEEDS OF THE WOLLASTON
‘DONATION FUND’

Mr. William Smith.
Mr. William Lonsdale.
M. Louis Agassiz.

Dr. Gideon A. Mantell.
Prof. G. P. Deshayes.
Sir Richard Owen.
Prof. C. G. Khrenberg.
Mr. J. De Carle Sowerby.
Prof. Edward Forbes.
Prof. John Morris.
Prof. John Morris.

My. William Lonsdale.
Mr. Geddes Bain.

Mr. William Lonsdale.
M. Alcide d’Orbigny.

Cape of Good Hope fossils.
M. Alcide d’Orbigny.
Mr. William Lonsdale.
Prof. John Morris.

M. Joachim Barrande.

Prof. John Morris.

Prof. L. G. de Koninck.

Dr. Samuel P. Woodward.
Dr. G. Sandberger.

Dr F. Sandberger.

Prof. G. P. Deshayes.

Dr. Samuel P. Woodward.

Prof. James Hall.

Mr. Charles Peach.

Prof. T. Rupert Jones.
Mr. W. K. Parker.
Prof. Auguste Daubrée.
Prof. Oswald Heer.

Prof. Ferdinand Senft.
Prof. G. P. Deshayes.
Mr. J. W. Salter.

Dr. Henry Woodward.
Mr. W. H. Baily.

M. J. Bosquet.

Dr. William Carruthers.
M. Marie Rouault.

Mr. Robert Etheridge.
Dr. James Croll.

Prof. John Wesley Judd.

1874.
1875.
1876.
1877.
1878.
1879.
1880.
1881.
1882.
1883.
1884.
1885.
1886.
1887.
1888.
1889.
1890.
1891.
1892.
1893.
1894.
1895.
1896.
1897.
1898.
1899.
1900.
1901.
1902,
1903.
1904.
1905.
1906.
1907.
1908.
1909.
1910.
1911.
1912.
1913.
1914.
1915.
1916.
1917.

XX1X

Dr. Henri Nyst.

Prof. Louis C. Miall.

Prof. Giuseppe Seguenza.
Mr. Robert Etheridge, jun.
Prof. William J. Sollas.
Mr. Samuel Allport.

Mr. Thomas Davies.

Dr. Ramsay H. Traquair.
Dr. George Jennings Hinde.
Prof. John Milne.

Mr. Edwin Tulley Newton.
Dr. Charles Callaway.

Mr. J. Starkie Gardner.

Dr. Benjamin Neeve Peach.
Dr. John Horne.

Dr. A. Smith Woodward.
Myr. William A. E. Ussher.
Mr. Richard Lydekker.

Mr. Orville Adelbert Derby.
Mr. John George Goodchild.
Dr, Aubrey Strahan.

Prof. William W. Watts.
Dr. Alfred Harker.

Dr. Francis Arthur Bather.
Prof. Edmund J. Garwood.
Prof. John B. Harrison.

Dr. George Thurland Prior.
Dr. Arthur Walton Rowe.
Mr. Leonard James Spencer.
My. L. L. Belinfante.

Miss Ethel M. R. Wood.
Dr, Henry Howe Bemrose.
Dr. Finlay Lorimer Kitchin.
Dr. Arthur Vaughan.

Dr. Herbert Henry Thomas.
Mr. Arthur J. C. Molyneux.
Mr. Edward B. Bailey.
Prof. Owen Thomas Jones.
Mr. Charles Irving Gardiner.
Mr. William Wickham King.
Mr. R. Bullen Newton.

Mr. Charles Bertie Wedd.
Mr, William Bourke Wright.
Prof. Perey G. H. Boswell.

PROCEEDINGS OF THE GEOLOGICAL SOcIETY. [ vol. lxxili,

AWARDS OF THE MURCHISON MEDAL

UNDER TFE CONDITIONS OF THE

‘MURCHISON GEOLOGICAL FUND,

ESTABLISHED UNDER THE WILL OF THE LATE

SIR RODERICK IMPEY MURCHISON, Barr., 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 knowledge, 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.
1874.
1875.
1876.
1877.
1878.
1879.
1880.
1881.
1882.
1883.
1884.
1885.
1886.
1887.
1888.
1889.
1890.
1891.
1892.
1893.
1894,
1895.

Mr. William Davies.

Dr. J. J. Bigsby.

Mr. W. J. Henwood.

Mr. Alfred R. C. Selwyn.
The Rev. W. B. Clarke.
Prof. Hanns Bruno Geinitz.
Sir Frederick M‘Coy.

Mr. Robert Etheridge.

Sir Archibald Geikie.

Prof. Jules Gosselet.

Prof. H. R. Geeppert.

Dr. Henry Woodward.

Dr. Ferdinand von Roemer.
Mr. William Whitaker.
The Rev. Peter B. Brodie.
Prof. J. S. Newberry.
Prof. James Geikie.

Prof. Edward Hull.

Prof. Waldemar C. Brégger.

Prof. A. H. Green.

The Rey. Osmond Fisher.
Mr. William T. Aveline.
Prof. Gustaf Lindstrém.

| 1896.
1897.
1898.

1899.

1900.
1901.
1902.
1903.
1904.
1905.
1906.
— 1907.
— 1908.
| 1909.
1910.
1911.
1912.
1913.
1914,
1915.

1916.
1917.

Mr. T. Mellard Reade.

Mr. Horace B. Woodward.

Mr. Thomas F.. Jamieson.
Dr. Benjamin Neeve Peach.

ee John Horne.

Baron A. Ei. Nordenskiold.
Mr. A. J. Jukes-Browne.
Mr. Frederic W. Harmer.
Dr. Charles Callaway.

Prof. George A. Lebour.
Mr. Edward John Dunn.

Dr. Charles T. Clough.

Dr. Alfred Harker.

Prof. Albert Charles Seward.

Prof. Grenville A. J. Cole.

Prof. Arthur P. Coleman.

Mr. Richard Hill Tiddeman.

Prof. Louis Dollo.

Mr. George Barrow.

Mr. William A. E. Ussher.

Prof. William W. Watts.

Dr. Robert Kidston.

Dr. George F. Matthew.

part 1] ANNUAL REPORT. Xxx

AWARDS

OF THE

BALANCE OF THE PROCEEDS OF THE
‘MURCHISON GEOLOGICAL FUND,’

1873. Prof. Oswald Heer. 1895. Prof. Albert CharlesSeward.

1874. Mr. Alfred Bell. 1896. Mr. Philip Lake.

Prof. Ralph Tate. 1897. Mr. Sydney 8. Buckman.
1875. Prof. H. Govier Seeley. 1898. Miss Jane Donald.
1876. Di. James Croll. 1899. Mr. James Bennie.
1877. The Rev. John F. Blake. 1900. Mr. A. Vaughan Jennings.
1878. Prof. Charles Lapworth. 1901. Mr. Thomas 8. Hall.
1879. Mr. James Walker Kirkby. | 1902. Sir Thomas H. Holland.
1880. Ms, Robert Etheridge. 1903. Mrs. Elizabeth Gray.
1881. Mr. Frank Rutley. ~ | 1904, Dr. Arthur Hutchinson.
1882. Prof. Thomas Rupert Jones, | 1905. Prof. Herbert L. Bowman.
1883. Dr. John Young. 1906. Dr. Herbert Lapworth.
1884, Mr. Martin Simpson. 1907. Dr. Felix Oswald.
1885. Mr. Horace B. Woodward. | 1908. Miss Ethel Gertrude Skeat.
1886. Mr. Clement Reid. 1909. Dr. James Vincent Elsden.
1887. Dr. Robert Kidston. 1910. Mr. John Walker Stather.
1888. Mr. Edward Wilson. 1911. Mr. Edgar Sterling Cobbold.

1889, Prof. Grenville A. J. Cole. 1912. Dr. Arthur Morley Davies.
1890. Mr. Edward B. Wethered. 19138. Mr. Ernest E. L. Dixon.

1891. The Rev. Richard Baron. 1914. Mr.Frederick Nairn Haward.
1892, Mr. Beeby Thompson. 1915. Mr. David Cledlyn Evans,
1893. Mr. Griffith John Williams, | 1916. Mr. George Walter Tyrrell.
1894. Mr. George Barrow. 1917. Dr. William Mackie.

XXX11 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ vol. lxxiu,

AWARDS OF THE LYELL MEDAL
UNDER THE CONDITIONS OF THE
‘LYELL GEOLOGICAL FUND,’
ESTABLISHED UNDER THE WILL AND CODICIL OF THE LATE

SIR CHARLES LYELI, Banrrt., F.R.S., F.G.S.

The Medal ‘ to be cast in bronze and 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
reference to the sex or nationality of the author, or the language in which any
such memoir or paper may be written.’

There is a further provision for suspending the award for one year, and in
such case for the awarding of a Medal to ‘each of two persons who have been
jointly engaged in the same exploration in the same country, or perhaps on
allied subjects in different countries, the proportion of interest always not beime
less to each Medal than one third of the annual interest.’

1876. Prof. John Morris. 1898. Prof. Wilhelm Waagen.
1877. Sir James Hector. 1899. Lt.-Gen. C. A. McMahon.
1878. Mr. George Busk. 1900. Prof. John Edward Marr.

1879. Prof. Edmond Hébert.

| 1901. Dr. Ramsay H. Traquair.
1880. Sir John Evans. |

, Jj Prot. Anton Fritsch.
1881. Sir J. William Dawson. | 190?: 1 Me Richard Lydekker.
1882. Dr. J. Lycett. | 1903. Mr. Frederick W. Rudler.
1883. Dr. W. B. Carpenter. _ 1904. Prof, Alfred G. Nathorst.
1884. Dr. Joseph Leidy. _ 1905. Dr. Hans Reusch.
1885. Prof. H. Govier Seeley. 1906. Prof. Frank Dawson Adams.
1886. Mr. William Pengelly. _ 1907. Dr. Joseph F. Whiteaves.

1887. Mr. Samuel Allport. 1908. Mr. Richard Dixon Oldham.
1888. Prof. Henry A. Nicholson. 1909. Prof. Perey Fry Kendall.
1889. Prof. W. Boyd Dawkins. | 1910. Dr. Arthur Vaughan.

1890. Prof. Thomas Rupert Jones. | 191

Dr. Francis Arthur Bather.
1891. Prof. T. McKenny Hughes. Dr. Arthur Walton Rowe.
1892. Mr. George H. Morton. 1912. Mr. Philip Lake.
1893. Mr. Edwin Tulley Newton. | 1918. Mr. Sydney S. Buckman.
1894. Prof. John Milne. 1914, Mr. C. S. Middlemiss.
1895. The Rey. John F. Blake. 1915. Prof. Edmund J. Garwood.

1896. Dr. A. Smith Woodward. 1916. Dr. Charles W. Andrews.
1897. Dr. George Jennings Hinde. | 1917. Dr. Wheelton Hind.

part 1]

1876,
1877.
1878.
1879.
1879.
1880.
1881.
1881.
1882.
1882.
1883.
1883.
1884.
1885.
1886,
1887.
1888.
1888.
1889.
1890.
1891.
1891.
1892.
1892.
1893.
1898.
1894.
1895.
1895.
1896.
1896.
1897.
1897.
1898.
1898.

AWARDS

ANNUAL REPORT

OF THE

XXXll

BALANCE OF THE PROCEEDS OF THE
‘LYELL GEOLOGICAL FUND,’

Prof. John Morris.

Mr. William Pengelly.
Prof. Wilhelm Waagen.
Prof. Henry A. Nicholson.
Dr. Henry Woodward.
Prof. F. A. von Quenstedt.
Prof. Anton Fritsch.

Mr. G. R. Vine.

The Rev. Norman Glass.
Prof. Charles Lapworth.
Mr. P. H. Carpenter.

M. Edmond Rigaux.

Prof. Charles Lapworth.
Mr. Alfred J. Jukes-Browne.
Mr. David Mackintosh.
The Rev. Osmond Fisher.
Dr. Arthur H. Foord.

Mr. Thomas Roberts.
Prof. Louis Dollo.

Mr. C. Davies Sherborn.
Dr. C. I. Forsyth-Major.
Mr. George W. Lamplugh.
Prof. John Walter Gregory.
Mr. Edwin A. Walford.
Miss Catherine A. Raisin.
Mr. Alfred N. Leeds.

Mr. William Hill.

Prof. Percy Fry Kendall.
Mr. Benjamin Harrison.
Dr. William F. Hume.
Dr. Charles W. Andrews.
Mr. W. J. Lewis Abbott.
Mr. Joseph Lomas.

“Mr. William H. Shrubsole.

Mr. Henry Woods.

VOL. LXXIII.

1899.
1899.
1900.
1901.
1901.
1902.
1903.
1903.
1904.
1904.
1905.
1905.
1906.
1906.
1907.
1907.
1908.
1908.
1909.
1909.
1910.
1910.
191.
1912.
1912.
1913.
1914.
1914.
1915.
1916.
1916.
1916.
1917.
1917,

My. Frederick Chapman.
Mr, John Ward.

Miss Gertrude L. Elles.

Dr. John William Evans.
Mr. Alexander McHenry.
Dr. Wheelton Hind.

Mr. Sydney S. Buckman.
Mr. George Edward Dibley.
Dr. Charles Alfred Matley.
Prof. Sidney Hugh Reynolds.
Dr. E. A. Newell Arber.
Dr. Walcot Gibson.

Prof. W. G. Fearnsides,
Mr. Richard H. Solly.

Mr. T. Crosbee Cantrill.
Mr. Thomas Sheppard. :
Prof. T. Franklin Sibly.
Mr. H. J. Osborne White.
Mr. H. Brantwood Maufe.
Mr. Robert G. Carruthers.
Dr. F. R. Cowper Reed.
Dr. Robert Broom.

Prof. Charles Gilbert Cullis.
Dr. Arthur R. Dwerryhouse.
Mr. Robert Heron Rastall.
Mr, Llewellyn Treacher.
The Rey. Walter Howchin.
Mr. John Postlethwaite.
Mr. John Parkinson.

Dr. Lewis Moysey.

Mr. Martin A. C. Hinton.
Mr, Alfred S. Kennard.
Dr. A. Hubert Cox.

Mr. Tressilian C. Nicholas,

XXXIV PROCEEDINGS OF THE GEOLOGICAL soctety. — { vol. lxxiil,

AWARDS OF THE BIGSBY MEDAL,

FOUNDED BY THE LATE
Dr. J. J. BIGSBY, F.BS., F.GS.
To be awarded biennially ‘as an acknowledgment of eminent services in any depart-

ment of Geology, irrespective of the receiver’s country; but he must not be-

older than 45 years at his last birthday, tlus probably not too old for further
work, and not tod young to have done much.’

1877. Prof. Othniel Charles Marsh. ; 1899. Prof. T. W. Edgeworth

1879. Prof. Edward Drinker Cope. | David.

1881. Prof. Charles Barrois. | 1901. Mr. George W. Lamplugh.
1883. Dr. Henry Hicks. _ 1903. Dr. Henry M. Ami.

1885. Prof. Alphonse Renard. | 1905. Prof. John Walter Gregory.
1887. Prof. Charles Lapworth. 1907. Dr. Arthur W. Rogers.
1889. Sir Jethro J. H. Teall. , 1909. Dr. John Smith Flett.

1891. Dr. George Mercer Dawson. 1911. Prof. Othenio Abel.
1893. Prof. William J. Sollas. 1913. Sir Thomas H. Holland.

1895. Dr. Charles D. Walcott. , 1915, Dr. Henry Hubert Hayden,
1897. Mr. Clement Reid. ! 1917. Mr. Robert G. Carruthers.

AWARDS OF THE PRESTWICH MEDAL,
ESTABLISHED UNDER THE WILL OF THE LATE

SIR JOSEPH PRESTWICH, F.R.S., F.GS.

‘To apply the accumulated annual proceeds ... at the end of every three years, in
providing a Gold Medal of the value of Twenty Pounds, which, with the
remainder of the proceeds, is to be awarded .:.to the person or persons, either
male or female, and either resident in England or abroad, who shall have done well
for the advancement of the science of Geology ; or, from time to time to accumulate
the annual proceeds for a period not exceeding six years, and apply the said
accumulated annual proceeds to some cbject of special research bearing on
Stratigraphical or Physical Geology, to be carried out by one single individual or
by a Committee; or, failing these objects, to accumulate the annual proceeds for
either three or six years, and devote such proceeds .to such special purposes as
wmity be decided.’

1903. John Lubbock, Baron Avebury.
1906. Mr. William Whitaker.

1909. Lady (John) Evans.

1912. Library extension.

1915. Prof. Emile Cartailhac.

> ami inate

part 1]

ANNUAL REPORT.

XXXV

AWARDS OF THE PROCEEDS OF THE BARLOW-
| JAMESON FUND,

ESTABLISHED UNDER THE WILL OF THE LATE

Dr. H. C. BARLOW, F.G.S.

The perpetual interest to be applied every two or three years, as may be approved by
the Council, to or for the advancement of Geological Science.’

1879.
1881.

1882,
1884,
1884.
1886.
1888.
1890.
1892.
1893.

1894.
1896.
1896.
1898.

Purchase of microscope.

Purchase of microscope- | 1900.
lamps. 1902.
Baron C. von Ettingshausen. | 1904.

Dr. James Croll.

Prof. Leo Lesquereux.

Dr. H. J. Johnston-Lavis.

Museum.

Mr. W. Jerome Harrison.

Prof. Charles Mayer-Eymar.

Scientific instruments for
Capt. EK. F. Younghusband.

Dr. Charles Davison.

Mr. Joseph Wright.

Mr. John Storrie.

Mr. edward Greenly.

1908.

1911.

TOUT.

| 1900.

1906.

1913.
1915.

Mr. George C. Crick.

Dr. Theodore T. Groom.

My. William M, Hutchings.

Mr. H. J. Ll. Beadnell.

Mr. Heury C. Beasley.

Contribution to the Fund for
the Preservation of the
‘Grey Wether’ sarsens
on Marlborough Downs.

Mr. John Frederick Norman
Green.

Mr. Bernard Smith.

Mr. John Brooke Scrivenor.

Mr. Joseph G. Hamling.

Mr. Henry Dewey.

AWARDS OF THE PROCEEDS OF THE
‘DANIEL PIDGEON FUND,’

FOUNDED BY MRS. PIDGEON, IN ACCORDANCE WITH THE

WILL OF THE LATE

DANIEL PIDGEON

Gs

‘An annual grant derivable from the interest on the Fund, to be used at the
discretion of the Council, in whatever way may in their opinion best promote
Geological Original Research, their Grantees being in all cases not more than
twenty-eight years of age.’

1903.
1904.
1905.
1906.
1907.
1908.
1909.
1910.

Prof. E. W. Skeats. 1911.
Mr. Linsdall Richardson. } 1912.
Mr. Thomas Vipond Barker, 1913.
Miss Helen Drew. | 1914.
Miss Ida L. Slater. _ 1916.
Dr, James A. Douglas. | 1916.
Dr. Alexander M. Finlayson. 1917.
Mr. Robert Boyle. |

My. Tressilian C. Nicholas.
Mr. Otway H. Little.

Mr. Roderick U. Sayce.
Prof. Perey G. H. Boswell.
Mr. KE. Talbot Paris.

Dr. John K. Charlesworth
Dr. Arthur Holmes.

c2

XXXV1 PROCEEDINGS OF THE GEOLOGICAL SOCIETY.

[vol. lexiii,

Estimates for

INCOME EXPECTED.

& s. d

CasipOsiiOns 125 2 os 5 Ae ao eee Oe ohana ee
Arrears of Admission-Fees .......... ot eta oe
Admission-Fees, 1917 ............ ois alone, tO eee
Arrears of Annual Contributions............ 150 0 0
Annual Contributions, $917.2 =. 23 1646 16 0
Annual Contributions in advance............ 60 0 0
Sale of the Quarterly Journal, including Long-

WSN BOA CCOMRD Sea tot oe eee eee
Sale of other Publications ...........-cee.
Miscellaneous Reeeipts ...:....6. s022ee5% ae
Interest on Deposit-Account and on War Loan*
Dividends on £2500 India 5 per cent. Stock .. 75 O O
Dividends on £300 London, Brighton, & South

Coast Railway 5 per cent. Consolidated Pre-

ference Steels. 4 au onc eee ete See ee 15 0 0
Dividends on £2250 London & North-Western

Railway 4 per cent. Preference Stock...... 90 0 0
Dividends on £2800 London & South-Western

Railway 4 per cent. Preference Stock ...... 112 0.0
Dividends on £2072 Midland Railway 23 per

cent. Perpetual Preference Stock.......... 51 16 O

Dividends on £267 6s.7d. Natal 3percent.Stock, 8 O O

* The Council on January 24th, 1917, authorized the
Treasurer to apply, on behalf of the Society, for £500 War
Loan (1925-1947) Inscribed Stock.

6. ee

2° OD
171L- 0.0
1856 16 O
88 8 0
o.0'8

16 SD S38

35 O 0
35116 0
£2553 0: D

—_—

part 1] FINANCIAL REPORT.

the

&
House-Expenditure :
SA A oh ets Ci ieiate caatet Asan ee OMT ES eer 0
Fire- and other Insurance ....................8605 31
Electric Lighting and Maintenance ............ 40
(GELS) coe e MR Slag ee eta CeO A as er 15
“TOG, don SS ae ORR O RA the Ona oes Ae ea 50
[Quand eyerh 003 Il Sif) 0128 b a: 15
-House-Repairs and Maintenance ............... iy
POUR COLORING 5 foe cs vcs vcs e sewed sie'ealedvaesoe veo 15
Washing and Sundry Eixpenses.................. 40
OGRE, ILIG 217071 Oa 20

Year 1917.

EXPENDITURE ESTIMATED.

|
|

Salaries and Wages, etc. :

IPOMMaAnent SECLEtALY. ili... 6s e eee csiaeesvesewnes 360

e half Premium Life-Insurance... 10
MME ME EMOTE fea ia tek foc tk oiek vies eealecih woes 170
RAE yA SSISCAMG O32 os. ccsans ssecesceenebescesvens 81
COLGTSE - ncalp Sc ee SOIREE 105
Lda ie CTU Cee SR ile nee er tan?
PINT AA SISGAIUG Bec y's. ijedssccaeer ever eases Gevnes 5D
House-Porter and Wife ................cc cc cee eee 94
| OWES RIFT] SEARS RR Peo ah eg re ae 57
Charwoman and Occasional Assistance ...... 20
UO COUMUAMES: OC) soi cccse ace lecccesdh levaduconves 10

Office-Expenditure :

PER EOUN MER ee oe, Aariahet ites AY cad uk ee Lers.es 15
Miscellaneous Printing ..................0cccee eee 50
Postages and Sundry Eixpenses.................5 65

Library (Books and Binding)...

Library Catalogue :

eshte on as vieiha nc dere ceune Vive aoe 10

Publications :

Quarterly Journal, including Commission on
MNT R thGie tran doy eeis ov caaonail ebaaatheraen 700
Postage on Journal, Addressing, etc. ......... 80
Abstracts of Proceedings, including Postage. 100
MEI ETOL HOLLOW ©. 3 ha vecsan'edges aatiwvicmrrarweads 40

15

ooooocoo°o &

—
CcCononwmnoooornso

=

oo ooo

2 See

Camiaiatise Eee cerabiemet eso re tne 1200 OO

XXXVIl
ah ees Ge
0
0
0
0
0
0
0
0
0
0

DADs: teri @)
0
0
0
0
0
0
0
0
0
0
0
1080 19 O
0
0
0
130 0 O
0
0
60;°0.°.0
0
0
0
0
9200.0
£25538 O O

JAMES VINCENT ELSDEN, Treasurer.

February 5th, 1917.

XXXV1 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ vol. lxxiil,

Estimates for

INCOME EXPECTED.

& s: at £3...
COMIPOSMOWS = 5S 0s aac Bo lade hiteasgee : 35 0 0
Arrears of Admission-Fees .......... oe seated eee
Admission-Fees, 1917 ....... ns suhee. e's wes
——— 171 0 0
Arrears of Annual Contributions............ 150 0 0
Annual Contribitions, L907: O08, osc e dee ce 1646 16 0
Annual Contributions in advance......... cee) OD ee
——— 185616 0
Sale of the Quarterly Journal, including Long-

TiN SA CCOUNE NT: URS eres es oe ee aes 88 S30
Sale of other Publications ...........+«. , 5 0 0
Miscellaneous, Reeeipis 24 /fk... 22. Sse eazce sh ae 10 0 0
Interest on Deposit-Account and on War Loan* 35 0 0
Dividends on £2500 India & per cent. Stock .. 75 O O
Dividends on £300 London, Brighton, & South

Coast Railway 5 per cent. Consolidated Pre-

FORCUCE' LORI ae sive oe he oe SR eee ke oe lo 30-48
Dividends on £2250 London & North-Western

Railway 4 per cent. Preference Stock...... 90 0 0
Dividends on £2800 London & South-Western

Railway 4 per cent. Preference Stock ...... M2 O58
Dividends on £2072 Midland Railway 23 per

cent. Perpetual Preference Stock.......... 51 16 0
Dividends on £267 6s.7d.Natal Spercent.Stock, 8 O O

—-—— 385116 0
£2553 0 0

* The Council on January 24th, 1917, authorized the
Treasurer to apply, on behalf of the Society, for £500 War
Loan (1925-1947) Inscribed Stock.

part 1] : FINANCIAL REPORT. XXXVI
the Year 1917.

EXPENDITURE ESTIMATED.

eas. 1d, ee Se a.
House-Expenditure :
SMI. ote, on Tal a nutae ua tale aa ME Lek ta Ser 015 0
Fire- and other Insurance ................:0.00005 ok 6: 0
Electric Lighting and Maintenance ............ 40 0 O
PNM arise de oe aeed seek Waser onadtas wach elles Lor Oho
LIGASE Beene re a 50: OF 0
MuMitUro aNd NEPaiTS 26. .cs ce cssacnseevnecss ces ee Ove 0
~House-Repairs and Maintenance ............... 158 O%,-0
PPE LOAVES 208 cas casge vevdciccsileg daccss see Tae Oks @,
Washing and Sundry Expenses.................. AOE OF a O
MGA MECOUING Sooo ccs cadict sie iceucurebaccuesseves 20 0 0

———_ 242 1 O
Salaries and Wages, etc. :

Permanent Secretary .............ccccvesevssssenes 360 0 0
S half Premium Life-Insurance... 1015 0
LAT ECREIOTIT ca). SANE IE a ee L7G 0. 0
RTC UO ASBISUAM L205... ccc css seeces ded etvectaanees Sia Ona)
CLELIE a2. 0h AA ORs eee ee 105 07. 0
LUE SEE CLOGS GA Se ai Pe in Ae decir er ENE O20
MEIC PACSIQGADD fc ccce cies searentacersesscedevers 55 12 0
House-Porter and Wife .................0:ce eens 94. OL 0
RES IEMIR Reet Sere. oe de eae wali nics sik cs on wae Eisele vole Dee DidiamccO
Charwoman and Occasional Assistance ...... 20 0 0
Accountants’ Fee ............ EARS, cnet a BER Sa 1010" 0
1080 19 O
Office-Expenditure :
DEE NOME Vaya IES Mechel Sarasa sete P08 dv Fe oy aie 1 ogee 15 0
Miscellaneous Printing ..................cc0cee ees 50 0 0
Postages and Sundry Eixpenses.................5 65 010
130 O O
Prpraby(ookeand Binding) <2 ..6. 1. ee ee ie ees 120 0 O
Library Catalogue :
OAPOTS) agp at ee aa Loe Oe 0
(PELOTON hat RS 50 0 0
COSA Oso
Publications :
Quarterly Journal, including Commission on
SELLE 4 aR 3 Sas one CNS IR an ee 700 0 0
Postage on Journal, Addressing, etc. ......... 80 0 0
Abstracts of Proceedings, including Postage. 100 0 0
SERGE ELOLLOWE! «3, tia clea sadesaavs vodeen ne avy’ 40 0 0
920 0 O
£2553 O O

JAMES VINCENT ELSDEN, Treasurer.
Hebruary dth, 1917.

Income and Expenditure during the
RECEIPTS.

oe: © a ae
To Balance in the hands of the Bankers at

Janey 1st, 8O8e mvt... 5 ck eee 12713 7
» do. do. Deposit Account ............ 500 0 0
, Balance in the hands of the Clerk at
damuary- fst, FOUG os. 0.2. nz ees 7AD 8
——— 635 13 4
gy Coin postionss, Sy. sedevors is oe 105 O O
,, Admission-Fees :
AITCAEE C7 Sets. heehee 44 2 0
Gurregh =e 220.9: setae wees 170 2-22 ae
Jeeves cde
, Arrears of Annual Contributions ...... 141 6 6
., Annual Contributions for 1916 :—
Resident Fellows ............... 1689 19 6
,, Annual Contributions in advance ...... 64 7 OU
—— 1895 13 O
,, Publications :
Sale of Quarterly Journal : *
, Vols.i to lxx (less Commission
SAK Gs. Oa oo al aetna SY gee Cae =
» Vol. Ixxi (less Commission
aoe Sis id.) 1... eee ee eee 30 10 6
———-. $7 11 ll
., Other Publications (less Commission)............ 4 13 11
,, Miscellaneous Receipts ........ Re ie tree ( 9: Se2G
> Interest on Deposit 2.2.055..4. Aa. ae
», Dividends (less Income-Tax) —
£2500 India 3 per cent. Stock ............ po Lee
£300 London, Brighton, & South Coast
Railway 5 per cent. Consolidated
Preference Stock .................. 12h 0
£2250 London & North-Western Railway
4 per cent. Preference Stock...... wo 13 9
£2800 London & South-Western Railway
4 per cent. Preference Stock...... Ol 44-8
£2072 Midland Railway 23 per cent. 5
Perpetual Preference Stock ...... Aimee, | Paco
£267 6s. 7d. Natal 3 per cent. Stock...... bi 6
-—— 28 2 2

,», income-Tax recovered: — 2:2... s.¥dccusepds scdcva. he) ee

* A further sum is due from Messrs. Longmans ———

& Co. for Journal-Sales, ete. ... £28 13 9 £3303 16 5

_ Fear ended December 31st, 1916.

PAYMENTS.
as House-Expenditure : ers dy en Bere
EE ie 9 eee ee reer LBS
Fire- and other Insuranee ..................... es AE Ns aa
Electric Lighting, Installation and Main-
(SoS ee 33 19 10
Sony eae Se Eat PE gan ee Sy Sie eee ee Te fie I eee
ot 2S ie eae eae ae tae 5112 0:
Hyenemee and Repairs <.....00. esses sees EOE 9504
House-Repairs and Maintenance ............ 86 3 3
eHM AER eCANINS 3... es ceca eee Ses 1 Sag ee a 03
Washing and Sundry Expenses. Pe Oe. Aare 42 17 6
Tea at Meetings Bt hike a Cae Re ee ete meee Lseades Z
397 12 6
, Salaries and Wages :
Permanent Secretary ...4....0....60.0...0see ees 360 0 0
a half Premium Life-Imsurance... 10 15 0
MISTEEPGAN fo iva chee vss ee 3S aoe ots 165 0 0O
Le a EE 02h 72 16 0
RM ee io rn ce fend ann vdé aelere tne 95-0770
0 BULA LE. BIg oR petiole 91 0 0
POEHOEPAORISEANG «056.650 boc. cscs oc ce vs eseedecses 54 12 0
House-Porter and Wife ...............0.....0.. 92 11 0
LL ELLLEN Jee seal Do oF ©
Charwoman and Occasional Assistance ... 1713 6
sc ST TG 2: a 10 10 0
PMP IS ADCO! osc. ese desis vuverves teases Le 86
_ Grant to Executors of the late Librarian... 10 0 0
D1 TLS OS ar 38 17 0
a0 7 ese 0 eae 9
», Oftice-Expenditure :
IS RAIPTEPTMEIR es! 6a as yuan vase sudan on ak -4- 9
Miscellaneous Printing .....................605 SG 2th. 26
Postages and Sundry Expenses............... SV ima ae
145 5 38
», Library (Books and Binding, etc.).................. (ol reel 2 esp.
», Library-Catalogue :
DED uo RSS SERS eine Sonera tees. 8
ROMER AGRON Ive. ec event ite ccaeevapenae ie HO OO
6) Seen ars |
», Publications :
Quarterly Journal, Vol. Ixxi, Paper,
Printing, and Ilustrations.................. joe LO 7
Postage on Journal, Addressing, etc. ...... 69° 9. 0
Abstracts of Proceedings, including Postage 96 17 10
RPE CULAWAI SS coo. tu isc viviystkeiiccstevecvsss a 6 G
798 12 11
* edi 14 5 6
», Refund of Ponnbation Beccrved in eaieaners in
1915. (Fellow since deceased) ......... ae Bey oO
,, Balance in the hands of the Bankers at
December 31st, 1916:
MPEPOMG A CGOUND.. 1c. 5.65.6. is cnetdans iva te 59 3 10
MEI EN CCOUR D665 55 osc odens Santen 600 0 0
» Balance in the hands of the Clerk at
@iecemper oist; 1916.....;....cc00. L702 8 F
676 12 5
We have compared this statement with £33038 16 5
the Books and Accounts presented to us, SannnEnnEEEEEEEREEE

and find them to agree.

BERNARD SMITH,

S. H. WARREN, Auditors.

JAMES VINCENT ELSDEN, Treasurer.

February d5th, 1917.

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mea

part 1] FINANCIAL REPORT.

Statement relating to the Society’s Property:

December 31st, 1916.

£ d.
Balance in the Bankers’ hands, December 31st,
1916:
MEMEMELOTD ACCOUNG, foc ccei sa cece ces cents cas on nee Doe LO
.», Deposit ORS SERN Le Seen Viedh sti 600 0 0
Balance in the Clerk’s hands, December 51st, 1916 17 ee

Due from Messrs. Longmans & Co., on account

of the Quarterly Journal, Vol. LXXI, etc. .... 2813 9
Atrears of Admission-Fees..........00..000008 AA Oe S0)

Arrears of Annual Contributions .............. 403 6 0

(Estimated to produce £150 Os. Od.)

Funded Property, at cost price :—

£2500 India 5 per cent. Stock ............ 2623 19

£300 London, Brighton, & South Coast Rail-
way 5 per cent. Consolidated Preference

18 6 Snes BSG as are 502 15
£2250 London & North-Western Railway

4 per cent. Preference Stock ............ 2898 10
£2800 London & South-Western Railway

4 per cent. Preference Stock ............ 3607
£2072 Midland Railway 23 per cent. Per-

petual Preference Stock ................ 1850 19
£267 6s. 7d. Natal 3 per cent. Stock ...... 250 O
£2000 Canada 33 per cent. Stock .......... 1982 11

6
0
0

xliti
rs, sd
676.12 5
476 1 9

£1152 14 2

———— £13716 2 9

[Notr.—The above amount does not include the valwe of the Library, Furniture,
and stock of unsold Publications. The value of the Funded Property of the
Society, at the prices ruling at the close of business on December 31st, 1916,

amounted to £7984 7s. 3d.]

JAMES VINCENT ELSDEN, Treasurer.
February 5th, (917.

xliv PROCEEDINGS OF THE GEOLOGICAL society. [vol. lxxiu,

AWARD OF THE WoLiLAston MEDAL.

In handing the Wollaston Medal, awarded to Prof. ANTOINE
Frangors ALFRED Lacrorx, F.M.G.S., to Sir ARCHIBALD GEIKIE,
O.M., for transmission to the recipient, the PresipEnr addressed
him as follows :— |

Sir ARCHIBALD GEIKIE,—

For a Medal instituted ‘to promote researches concerning the
mineral structure of the Earth,’ it would be difficult to find a fitter
recipient than Prof. Lacroix, to whose labours in the domain of
Mineralogy and Petrology our science is so deeply indebted.
His researches on the optical and crystallographic constants of
numerous minerals have given us a mass of useful data; but it has
always been his practice to extend his investigations to the field as
well as to the laboratory. His studies of the mode of occurrence,
the mutual associations, and the manner of origin of a host of
species have done much to rehabilitate Mineralogy as, not merely
a department of Physics and Chemistry, but a fascinating branch
of Natural History. His many separate papers deal with material
from all parts of the world; but of chief importance will always
be reckoned his four volumes on the Mineralogy of France and her
Colonies, a single-handed work unique in its wide scope and com-
prehensive treatment.

In Petrology, too, Prof. Lacroix’s contributions have been
numerous and many-sided. Of special note for their influence
upon the science are his researches on contact-metamorphism,
contained in the Bulletins of the Geological Survey of France, his
various memoirs treating of the inclusions in igneous rocks, and
his comparative study of the volcanic products of Mont Pelé,
followed by a like examination of the rocks of Vesuvius.

From the products of voleanoes to the physics of voleanic action
is a natural transition, and in respect of both Prof. Lacroix’s
mission to Martinique in 1902 was eminently fruitful in results.
In particular, he was able to elucidate two remarkable phenomena
previously unrecognized or unappreciated: the peculiar plugs or
domes formed under certain conditions by extruded lavas, and that
most terrible of all voleanic effects—the nuée ardente.

As a diligent student of his writings, I feel a special pleasure
in placing the Wollaston Medal in your hands for transmission

part 1] ANNIVERSARY MEETING—WOLLASTON MEDAL. xlv

to Prof. Lacroix. With no less pleasure, I am sure, will all
‘British geologists see his name added to a list which is already
graced by the names of Elie de Beaumont and Ami Boué, Daubrée
and Descloizeaux; and they will acclaim this award the more
cordially since, in doing homage to a distinguished savant, we are
honouring a citizen of a great nation, with which our own is linked,
as we hope, by enduring ties.

Sir ARCHIBALD GEIKIE replied in the following words :—

Mr. PRESIDENT,—

It is both a signal honour and a welcome pleasure to me to have
been requested by my friend Prof. Lacroix to receive this Medal on
his behalf. He has asked me to express to you and to the Society
his grateful thanks that you should have thought him worthy of
your highest prize, and at the same time to assure you how deep is
his regret that his official engagements prevent him from leaving
Paris and being with us here to-day. You are aware that he has
now added to his ordinary professional duties those of Secrétaire
Perpétuel de Académie des Sciences, thus following, at no great
interval of time, another eminent geologist of France, our lamented
Foreign Member A. de Lapparent.

You have sketched with well-merited appreciation the wide range
of investigation through which our latest Wollaston Medallist has
pursued his studies. He has united with pre-eminent skill the
detailed work of the laboratory with an appeal to the essential
evidence which can only be obtained in the field. In this latter
branch of research he has been fortunate in having as his com-
panion and fellow-labourer a devoted and enthusiastic wife.
Madame Lacroix, as the daughter of Ferdinand Fouqué, has
inherited her father’s scientific ardour, and has proved herself to
be as capable and enduring a mountaineer as her husband.

Prof. Lacroix has sent me a brief address to you, Mr. President,
expressive of his grateful recognition of the honour which the
Geological Society has conferred upon him. His handwriting,
however, is so difficult to decipher that I have ventured to make
a translation of this Address, which I will now read :—

‘Mr, PRESIDENT,—

‘No honour could be more appreciated by me than that which the Geolo-
gical Society of London has conferred upon me. Over and above the pride
which I feel in this award from so many competent judges, among whom are
not a few who pursue the same researches as those to which I have devoted

xlvi PROCEEDINGS OF THE GEOLOGICAL socrery. [ vol. lxxiii,

myself, there is added, in present circumstances, the further gratification to
see the ties strengthened which from old times have linked the men of science
in our two countries—Britain now striving with all her power and all her
soul, hand in hand with France in defence of Right and Liberty.

‘ You have wished this year, I am sure, to honour in a more special manner
French Geology, and this adds a further reason why I should be touched that
you have chosen me as the recipient of your prize.

‘In being so good as to represent me at your Anniversary, Sir Archibald
Geikie, for whose work I have as great an admiration as I have respectful
esteem for him personally, will convey to you, so far as that is possible, my
regret that my official duties here prevent me from being present with you,
and expressing with my own living voice all my gratitude.

*‘ Among the distant memories of my student-days there rises in my mind
the recollection of my old and dear master Descloizeaux, the friend of your
Miller, carefully taking out of a drawer in his writing-table the Wollaston
Medal, which he had some time before received from you, and showing it to
his pupils as one of the most valuable tokens of esteem that he had ever
received in the course of his long and laborious career.

‘ How indeed could one not be proud, though with all humility, to see one’s
name inscribed in your golden book below those of the Founders of our Science,
and following those among you who with such brilliance continue to maintain
their great and glorious inheritance

‘Be so good, Mr. President, as to receive the expression of my highest
consideration.

A. LACROIX.’

AWARD OF THE Mtrcuison MEDAL.

The PrestpENt then handed the Murchison Medal, awarded to
Dr. GeorGEeE Frepertc Marruew. to Dr. J. E. Marr for trans-
mission to the recipient, addressing him as follows :—

Dr. Marr,—

In awarding the Murchison Medal to Dr. G. F. Matthew, the
Council desires to mark its high appreciation of the services which
he has rendered to Geology, more particularly by his researches
among the Lower Paleozoic rocks of New Brunswick.

Engaged for many years in official duties, and enjoying little of
the advantages which come from association with fellow-workers
and from access to large libraries and museums, he has still found
time and means to make valuable contributions to our science. So
long ago as 1865 he communicated an important paper to this
Society. but most of his results have seen the light in Canadian
and American journals. Of first importance must be reckoned his
‘Tllustrations of the Fauna of the St. John Group,’ published by
the Royal Society of Canada, a work embodying much patient and
skilful research. A paper which appeared in 1895, in the Trans-
actions of the New York Academy of Sciences, contained the first

-

Bete te.

part1] | ANNIVERSARY MEETING—LYELL MEDAL. xlvu

account of the Protolenus fauna. Of other important contribu-

tions which Dr. Matthew has made to Lower Paleozoic geology, I
may mention his discoveries of the Etchiminian and the still older
Coldbrook fauna beneath what had previously been considered the
oldest fossiliferous horizon in New Brunswick. His work has been
distinguished throughout by a happy combination of stratigraphical
skill with paleontological knowledge, and some of his studies, such
as those on the evolution of the Cambrian Trilobites, have had far-
reaching consequences.

I have much pleasure in handing this Medal to you for trans-
mission to the veteran Canadian geologist, and hope that he will
see in ita token that his labours in the field of science are not

without recognition in this country.

Dr. Marr replied in the following words :—
Mr. PrREsIDENT,—

~The interval that has elapsed since the award of the Murchison
Medal has been too short, in these times of stress, to allow
Dr. Matthew to send an acknowledgment. Had he done so, he
would doubtless have expressed to the Council his gratification at
the honour conferred upon him.

I am glad to receive the Medal on his behalf, so that I, an old
friend, may add my appreciation of the value of his work, although
this is unnecessary after the sympathetic words which you, Sir, have
offered concerning it.

Dr. Matthew’s name is the latest in a long list of Canadians on
our roll of honour, for the men of the Dominion have excelled in
the field of our science, as latterly in another and a sterner field.

I feel that I may, on behalf of the Fellows of the Society, express
the wish that our Medallist, veteran though he be, may vet enjoy
many years in the study of his favourite science.

AWARD OF THE LyEnn MeDAt.

In handing the Lyell Medal, awarded to Dr. Witrenron Hix»,
F.R.CS., to Dr. A. Smitit Woopwarp for transmission to the
recipient, the PrestpEN't addressed him as follows :—

Dr. Surri Woopwarp,—

The Lyell Medal has been awarded by the Council to Dr. Wheelton

xlviii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ vol. Ixxiii,

Hind as a token that he has, in the words of its Founder,
‘deserved well of the Science.’

On the side of descriptive and systematic paleontology his two
memoirs on the Carboniferous Lamellibranchiata, published by the
Paleontographical Society, have long taken rank as standard
works, and he has supplemented them from time to time by many
other contributions dealing with the same subject. Further, he
has brought his paleontological knowledge to bear upon important
questions of stratigraphy, and has shown that the lamellibranch
faunas of different groups of rocks furnish valuable data for
purposes of comparison. In this way he has taken no small part
in the correlation of the Carboniferous strata in different areas in
Britain, and has further pushed his enquiries to the Continent of
Hurope.

The quantity, as well as the quality, of his geological work
seems the more remarkable, when we remember that his researches
have been carried out in the intervals, none too frequent, of a busy
professional life. In conferring upon him this mark of recognition,
so well earned, we are thus honouring one of those amateur workers
to whom British Geology has always been signally indebted. In
presenting it I express the hope that, when happier days bring
again some allowance of leisure, Dr. Hind will be able to renew
those investigations which have already proved so rich in results.

Dr. SmirH Woopwarp replied in the following words :—

Mr. PRESIDENT,—

I shall have much pleasure in transmitting the Lyell Medal to
my friend Dr. Wheelton Hind, on whom it has been so worthily
bestowed. Geological science has always been greatly indebted
to the medical profession for important advances made in their
brief intervals of leisure, and Dr. Hind has for many years
excellently maintained the old tradition. Recognizing the im-
portance of combining work in the field with detailed palonto-
logical research in the study, he soon became one of the most
successful exponents of the modern methods of stratigraphical
geology. Beginning researches on the Carboniferous rocks in his
own district of North Staffordshire, he has gradually extended his
domain until, as you have well said, Sir, he has taken no small
part in the correlation of the Carboniferous strata of Britain. So
soon as he is released from the military duties which prevent his

part 1] ANNIVERSARY MEETING—BIGSBY MEDAL. xlix

attendance at the meeting to-day, I feel sure that Dr. Hind will
return with renewed vigour to the geological work which has so
long been his recreation; and he desires me to express his best
thanks to the Council of the Geological Society for the stimulating
Award with which they have honoured him.

AWARD OF THE BrasBpy MEDAL.

The PrestpEnt then handed the Bigsby Medal, awarded to
Mr. Roperr GrorcGE CarrutrHErs, to Dr. A. Srranan, Director
of H.M. Geological Survey, for transmission to the recipient,
addressing him as follows :—

Dr. StRaAHAN,—

The Bigsby Medal has been awarded to Mr. Carruthers by the
Council as an acknowledgment of his eminent services to Scottish
Geology. As an officer of the Geological Survey he has investigated
considerable areas of the ancient rocks of the Highlands, the Carbon-

iferous of the Scottish Midlands, and the Old Red Sandstone of
Caithness; and in each of these fields his labours have yielded
results which possess more than a local interest. On the side of
pure Paleontology he has made important additions to our
knowledge of the Corals, in particular by his memoir dealing
with the morphology of the Rugosa; but especially are geologists
indebted to him for the use which he has made of the Corals in
the zonal subdivision of the Carboniferous succession. Of other
paleontological contributions having a direct stratigraphical appli-
eation, I will recall only his discovery of a Pendleside fauna in
the Calciferous Sandstone Series of Lanarkshire and his reference
of the fish-fauna of Achanarras to its true position in the Old Red
Sandstone sequence. Among his services to Economic Geology,
his revision of the memoir on the Oil-Shale Fields of the Lothians
is especially worthy of mention.

The Founder of this Medal, in fixing an age-limit for the
recipient, made clear his intention that regard should be had, not
only to performance in the past, but to promise for the future.
Confident that in this case the one is a sure guarantee of the other,
we ask him to receive this Award in the double acceptation of a
tribute and an encouragement.

VOL. LXXIII. d

xlviii PROCEEDINGS OF THE GEOLOGICAL SOcIETY. [ vol. Ixxiii,

Hind as a token that he has, in the words of its Founder,
‘deserved well of the Science.’

On the side of descriptive and systematic paleontology his two
memoirs on the Carboniferous Lamellibranchiata, published by the
Paleontographical Society, have long taken rank as standard
works, and he has supplemented them from time to time by many
other contributions dealing with the same subject. Further, he
has brought his paleontological knowledge to bear upon important
questions of stratigraphy, and has shown that the lamellibranch
faunas of different groups of rocks furnish valuable data for
purposes of comparison. In this way he has taken no small part
in the correlation of the Carboniferous strata in different areas in
Britain, and has further pushed his enquiries to the Continent of
Europe.

The quantity, as well as the quality, of his geological work
seems the more remarkable, when we remember that his researches
have been carried out in the intervals, none too frequent, of a busy
professional life. In conferring upon him this mark of recognition,
so well earned, we are thus honouring one of those amateur workers
to whom British Geology has always been signally indebted. In
presenting it I express the hope that, when happier days bring
again some allowance of leisure, Dr. Hind will be able to renew
those investigations which have already proved so rich in results.

Dr. SmrrH Woopwarp replied in the following words :—

Mr. PRESIDENT,—

I shall have much pleasure in transmitting the Lyell Medal to
my friend Dr. Wheelton Hind, on whom it has been so worthily
bestowed. Geological science has always been greatly indebted
to the medical profession for important advances made in their
brief intervals of leisure, and Dr. Hind has for many years
excellently maintained the old tradition. Recognizing the im-
portance of combining work in the field with detailed palonto-
logical research in the study, he soon became one of the most
successful exponents of the modern methods of stratigraphical
geology. Beginning researches on the Carboniferous rocks in his
own district of North Staffordshire, he has gradually extended his
domain until, as you have well said, Sir, he has taken no small
part in the correlation of the Carboniferous strata of Britain. So
soon as he is released from the military duties which prevent his

part 1] ANNIVERSARY MEETING—BIGSBY MEDAL. xhix

attendance at the meeting to-day, I feel sure that Dr. Hind will
return with renewed vigour to the geological work which has so
long been his recreation; and he desires me to express his best
thanks to the Council of the Geological Society for the stimulating
Award with which they have honoured him.

AWARD OF THE Brasspy MEDAL.

The PresipenT then handed the Bigsby Medal, awarded to
Mr. Ropert GEORGE CARRUTHERS, to Dr. A. Srranan, Director
of H.M. Geological Survey, for transmission to the recipient,
addressing him as follows :—

Dr. StRAHAN,—

The Bigsby Medal has been awarded to Mr. Carruthers by the
Council as an acknowledgment of his eminent services to Scottish
Geology. As an officer of the Geological Survey he has investigated
considerable areas of the ancient rocks of the Highlands, the Carbon-
iferous of the Scottish Midlands, and the Old Red Sandstone of
Caithness; and in each of these fields his labours have yielded
results which possess more than a local interest. On the side of
pure Paleontology he has made important additions to our
knowledge of the Corals, in particular by his memoir dealing
with the morphology of the Rugosa; but especially are geologists
indebted to him for the use which he has made of the Corals in
the zonal subdivision of the Carboniferous succession. Of other
paleontological contributions having a direct stratigraphical appli-
cation, I will recall only his discovery of a Pendleside fauna in
the Calciferous Sandstone Series of Lanarkshire and his reference
of the fish-fauna of Achanarras to its true position in the Old Red
Sandstone sequence. Among his services to Economic Geology,
his revision of the memoir on the Oil-Shale Fields of the Lothians
is especially worthy of mention.

The Founder of this Medal, in fixing an age-limit for the
recipient, made clear his intention that regard should be had, not
only to performance in the past, but to promise for the future.
Confident that in this case the one is a sure guarantee of the other,
we ask him to receive this Award in the double acceptation of a
tribute and an encouragement.

VOL. LXXIII. d

] PROCEEDINGS OF THE GEOLOGICAL society. [ vol. lxxi,

Dr. Srrawan replied in the following words :—
Mr. Presipent,—

It is a great pleasure to me to receive, on behalf of my col-
league on the Geological Survey, this testimony of the value that
the Council attaches to his work. You have referred in generous
terms to Mr. Carruthers’s contributions to our knowledge of
Scottish Geology, and to his researches in pure Paleontology.
His application of scientific methods of investigation to the
Corals has done much to elucidate stages of evolution in those
lowly organisms, and I believe that your recognition of this branch
of his work will be especially gratifying to him. In Economic
Geology the demands made upon the staff by the exigencies of war
were sudden and imperative, and no one knows better than myself
how well Mr. Carruthers and his colleagues responded to the call,
and for the time resisted the fascinations of abstract science.

My. Carruthers, writing amid the distractions of the Western
Front, tells me that it is

‘almost impossible to give any adequate expression of my gratitude to the

Society for their award of the Medal..... As the bulk of my work has
been concerned with Economic Geology, the honour of this award is shared
equally with my comrades on the Survey.... In the field of abstract science

my ventures have been little more than tentative. I hope that the generous
encouragement that they have always received from the Society may ulti-
mately be repaid in some degree. The obligation is, of course, greatly
increased by this additional proof of trust.’

May I express the hope, for myself and for the Fellows of the
Society, that it will not be long before Mr. Carruthers can resume
his scientific work and justify the confidence that you have so
gracefully expressed in his promise for the future ?

AWARD FROM THE WOLLASTON DONATION FUND.

In presenting the Balance of the Proceeds of the Wollaston
Donation Fund to Percy Grorce Hamnatt Boswett, D.Sc.,
the PrEsIDENT addressed him as follows :—

Dr. BoswELL,—
The Balance of the Proceeds of the Wollaston Donation Fund

has been awarded to you by the Council in recognition of your
work in East Anglia, by which you have added to our knowledge

part 1] ANNIVERSARY MEETING—-MURCHISON FUND. hh

of the subterranean as well as the superficial geology of that area.
In your earlier contributions you examined the origin of the exist-
ing river-system of Suffolk, and also endeavoured to define the
limits of extension of the Lower Glacial deposits of Norfolk into
the more southerly county. You have also made instructive re-
searches into the lithology and mineralogy of many of the sedi-
mentary deposits of East Anglia. In a paper read before this
Society two years ago you employed this method, in conjunction
with stratigraphical observation, in a comprehensive study of the
Lower Hocene strata of the area, and drew interesting conclusions
concerning the geography of the period and even the tectonics of
the country. Your more recent investigations concerning sands
suitable for glass-making have a direct practical application, of
much importance at the present time.

Some part of your work has been the outcome of a grant from
the Daniel Pidgeon Fund, and the good use which you made of
that opportunity assures us that you will regard the present Award
as an incentive to new enterprises in the service of Geology.

AWARD FROM THE Murcutison GEOLOGICAL Funp.

The PrestpEnt’ then handed the Balance of the Proceeds of the
Murchison Geological Fund, awarded to Dr. Wirnttam Macks,
to Dr. W. T. Gorpon, for transmission to the recipient, addressing
him as follows :—

Dr. GorDON,—

The Balance of the Proceeds of the Murchison Geological Fund
has been awarded by the Council to Dr. Mackie in recognition
of his contributions to the geology of Northern Scotland. <A
skilled chemist as well as a keen petrologist, he has utilized in
this way his leisure as a medical practitioner during the last
twenty years.

By his investigation of the sandstones of Eastern Moray he has
thrown light, both on the source of the material and on the climatic
conditions which prevailed during its deposition. In the cement
of these sandstones he detected traces of the heavy metals, and his
enquiry led to the discovery in quantity of barytes and fluor in the

ad 2

hi PROCEEDINGS OF THE GEOLOGICAL soctEry. [vol. xxiii,

Elgin Trias. His petrographical work includes an interesting
study of the granites of the North of Scotland, and he has also
carried out a large series of chemical analyses of igneous and sedi-
mentary rocks in order to elucidate theoretical questions suggested
in the course of his researches.

His recent discovery of plant-bearing cherts in the Old Red
Sandstone of Rhynie (Aberdeenshire), has added a new interest
to that formation. Dr. Kidston and Prof. Lang recognize these
cherts as silicitied layers of peat, and a new class of vascular
cryptogams, the Pszlophytales, has been made for the reception of
the plants which they contain.

I ask you, in forwarding this Award to Dr. Mackie, to convey to
him our hope that he will thereby be encouraged to continue the
researches which he has hitherto pursued with such enthusiasm.

AWARDS FROM THE LYELL GEOLOGICAL FUND.

The PrestpENnT then presented a moiety of the Balance of the
Proceeds of the Lyell Geological Fund to Arrnur HusBert Cox,
Ph.D., and addressed him in the following words :—

Dr. Cox,—

The Council has awarded to you one moiety of the Proceeds of
the Lyell Fund in recognition of the value of your work among
the Lower Paleozoic rocks. Since you read before this Society,
five years ago, a paper on the Pedwardine Inlier, you have devoted
much time to geological researches in Wales, both South and
North. Your paper on the Abereiddy and Abercastle district was
a valuable contribution to the stratigraphy and tectonics of Pem-
brokeshire, and gave evidence of skilful and accurate work in the
field. On the petrological side, too, it added to our knowledge of
the Ordovician igneous rocks, a subject to which you have also
given attention elsewhere. Your work in the Cader Idris district,
of which we have as yet only a preliminary account, seems to be
of the same thorough quality ; and, in thus marking our apprecia-
tion of what you have already done, we look forward to results not
less important from your geological labours in the time to come.

part 1] ANNIVERSARY MEETING—-BARLOW-JAMESON FUND. li

In handing the other moiety of the Balance of the Proceeds of
the Lyell Geological Fund, awarded to TreEsst~1an CHARLES
Nicuoras, M.A., to Mr. H. Woops, for transmission to the
recipient, the PrEsIDENT addressed him as follows :—

Mr. Woops,—

A moiety cf the Proceeds of the Lyell Fund has been awarded
to Mr. T. C. Nicholas as a mark of appreciation of his work on
the older Paleozoic rocks of Carnarvonshire. The results of that
work are represented first by a paper on the Geology of the
St. Tudwal’s Peninsula, in Lleyn, read before this Society in 1914.
Therein he gave a comprehensive account of the succession, fossil
contents, and classification of the Cambrian strata of the district,
and established the unconformity which exists between these beds
and the overlying Ordovician. This paper was supplemented in
the same year by a paleontological one dealing with the rich
trilobitic fauna, of Middle Cambrian age, which his researches had
discovered. A number of new and interesting species were
described, and the succession of forms was correlated with that
recorded for other areas.

As an old friend of Mr. Nicholas, and one who has seen some-
thing of the difficulties presented by the Lleyn district, I am
pleased that it falls to my lot to extend to him, on behalf of the
Council, this token of recognition of his geological and palzonto-
logical work.

AWARD FROM THE BiaRLOW-JAMESON FUND.

The PrestpENntT then presented the Balance of the Proceeds of
the Barlow-Jameson Fund to Mr. Henry Dewey, addressing him
as follows :—

Mr. DEwry,—

The Proceeds of the Barlow-Jameson Fund have been awarded
to you in recognition of your services to Geology and as an
encouragement to you for the future. In the record of your
geological work the first place belongs to your researches in North
Cornwall, where you were engaged as an officer of the Geological
Survey. There your mapping led you to recognize a number of

liv PROCEEDINGS OF THE GEOLOGICAL society. | vol. lxxim,

subdivisions of the Devonian strata and to determine their natural.
sequence, and with this help you were able to demonstrate the
existence of important overthrusts in that area. The peculiar
features of the ‘ pillow-lavas’ intercalated in the Upper Devonian
also engaged your attention, and your paper on the ‘spilitic series,’
written in collaboration with Dr. Flett, has proved a valuable
contribution to Petrology. Of not less consequence, of another
kind, were your paper on the Raised Beach of North Devon and
that which you read before this Society a year ago on the Origin
of River-Gorges in Cornwall and Devon. Your removal from the
West of England to the Thames Valley introduced you to new
problems, to which you have brought the same zeal and insight,
and it is our hope that you will find in the present Award an
incentive to further investigations in the field of Geology.

‘eee

y~

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. lv

THE ANNIVERSARY ADDRESS OF THE PRESIDENT,

ALFRED Harxer, M.A., LL.D., F.R.S.

THe death-roll for the last twelve months is a heavy one, and
includes not a few well-known names. In preparing notices
of some of our deceased Fellows, I have used various sources
of information, but especially I must acknowledge the help
kindly given by Prof. Cayeux, Mr. Lamplugh, Prof. Skeats, and
Mr. Barrington Brown, Jr.

The death of JuLEs GossELET, in his 84th year, removes the
doyen of French geologists, and one whose name stood second on
the roll of our Foreign Members. Born at Cambrai on August 19th,
1832, he very early gave evidence of scientific aptitudes of a high
order. After holding several minor appointments, he was chosen
in 1864 Professor of Geology & Mineralogy in the Faculty of
Sciences at Lille, a place which became thenceforth his home and
the centre of his multitudinous activities. His immediate task
was no light one. The Chair was newly created; library and
museum were alike wanting; and science did not at that time
enlist much interest in a busy industrial city. This last difficulty
disappeared like the rest before the zeal of the young Professor ;
and indeed his subsequent labours must have convinced the most
sceptical of the immense material benefit which may accrue to a
country from the cultivation of pure science.

Gosselet’s whole-hearted devotion to his work, and his ability to
communicate his enthusiasm to others, made him an ideal teacher.
His old students speak of him with an affectionate admiration,
which is a high tribute to his personal qualities no less than to
his powers as an instructor. The time and energy not absorbed by
professional duties he devoted to geological investigation. Here,
too, his example proved inspiring, for he was chiefly instrumental
in founding in 1870 the Société Géologique du Nord, of which he
continued to be to the last the guiding spirit.

Even before settling at Lille Gosselet had been attracted to the
Ardenne, already made famous by the pioneer labours of Omalius
d’Halloy and Dumont, and it was to the geology of that country
that he now addressed himself. He brought to the task a laborious

lvi PROCEEDINGS OF THE GEOLOGICAL socieTy. [ vol. lxxiu,

patience, joined to an insight which had something of the detec-
tive’s acumen and something of the poet’s imagination. During
ten years he produced in rapid succession papers treating of the
general structure of the district, the stratigraphy and fauna of
the Devonian formations, the ridges of Cambrian rocks which rise
in the midst of the younger strata, and the remarkable metamorphic
effects induced in connexion with the folding and overthrusting.
His results were finally collected in the masterly monograph
entitled ‘ L’Ardenne,’ which appeared in 1888, and was at once
recognized as a work of the first rank.

It would take long to enumerate all the contributions which
Gosselet made in succeeding years to almost every department of
geology. Remarkable for originality and freshness of interest,
they often had also important practical applications. Of chief
moment was the investigation of the structure of the Franco-
Belgian coal-basin. This was indeed the natural complement of
Gosselet’s study of the Ardenne, and he was able to show how the
Ardenne massif, or its prolongation, has been driven over the
southern margin of the coal-basin. This work had a decided
influence upon the doctrines then current concerning the structure
of the Alps, while on the practical side it led to an extension of
the workable coalfields. Gosselet was also attached to the Geolo-
gical Survey of France, and was responsible for numerous sheets
of the map with accompanying memoirs.

The value of his scientific labours was recognized both at home
and abroad. The Academy of Sciences of Paris had awarded him
the Bordin Prize in 1881, and when many years later the member-
ship of the Academy was extended to provincial savants, Gosselet’s
name figured on the first lst. Our Society awarded him the
Murchison Medal in 1882, and three years later elected him a
Foreign Member.

Still hale in mind and body at 70, the Professor was forced by
an unwelcome age-limit to relinquish his Chair; but a kindly fate
sent him for successor his old pupil and attached friend Dr. Charles
Barrois. An unofficial place was found for the elder man, and in
the leisure of retirement he saw merely enlarged opportunity for
geological activities. When darker days came, and Lille fell into
the hands of an ungenerous enemy, the veteran geologist refused
to quit the scene of his long labours. His last illness was con-
tracted while striving to repair the havoc wrought by an explosion
among his cherished collections. He died on March 20th, 1916,

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. lvii

and rests in the little cemetery of Landrecies, the home of his
boyhood.!

Joun Westy Jupp was born at Portsmouth on February 18th,
1840. His father was of a Kentish family long settled in the
Isle of Wight, and his mother was of Scottish descent. His
devotion to natural science declared itself at an early age; but,
although he had obtained first-class certificates in Geology and
Mineralogy from the Department of Science & Art, he found at
first no opening in this direction. He accordingly became in 1859
_ a master in a school at Horncastle, in Lincolnshire. There he
remained for three years, pursuing at the same time his studies in
chemistry and devoting his holidays to geological excursions in the
neighbourhood. In 1863, making another attempt to realize his
aspirations towards a scientific career, he entered the Royal School
of Mines, and was rewarded by winning one of the newly instituted
Royal Exhibitions. His design was to devote himself for a time
to research work, but in this he was again disappointed, and we
next find him engaged as an analytical chemist in iron and steel-
works at Sheffield. It was there that he made the acquaintance
of Sorby, and was introduced by him to the new method of studying
rocks in thin slices.

Judd’s residence at Sheffield terminated abruptly by reason of a
railway-accident, from the consequences of which he suffered for
a long time. Forbidden to undertake any regular employment,
he turned again to his geological work in Lincolnshire. By a
stratigraphical and paleontological study of the strata at the base
of the Chalk Wolds he was able to correlate them with the Neo-
comian of the Continent; and, extending his investigation to the
Yorkshire coast, he there identified the same zones under a different
facies. These researches formed the subject of his first two com-
munications to our Society. He next carried out a revision of
the Lower Oolites of Lincolnshire, and extended it into Yorkshire
in one direction and into the Midland counties in the other. This
he developed further in the course of his work on the Geological
Survey, which he joined, at the instance of Ramsay, in 1867, and
the results were embodied in the memoir on the Geology of Rutland
which appeared, after some delay, in 1875.

1 For many of the facts here recorded I am indebted to an interesting and
sympathetic notice by Prof. L. Cayeux, in the ‘ Revue générale des Sciences,’
July 15th, 1916.

lviii PROCEEDINGS OF THE GEOLOGICAL socrety. { vol. lxxi,

In the meantime Judd had quitted the Survey, and presently
found himself in a position to resume independent work in the.
field. He chose as a promising subject of study the Secondary
rocks of Scotland. Beginning with the isolated and little-known
exposures of these strata on the North-East coast, he was able
after two years of work to make out the true succession and corre-
lation of the several formations, ranging from the Trias to the’
Upper Oolites. He next transferred his attention to the West
Coast and the Inner Hebrides; but there he soon became absorbed
in a new interest. The Mesozoic rocks of the west have been
buried under great floods of lava of Tertiary age, and are only
partially exposed as the result of profound erosion in conjunction
with plateau-faulting. At certain centres, too, masses of Tertiary
plutonic rocks have broken through, and now build the mountains
of Skye, Rum, and Mull. Little systematic work had been done
upon these late igneous rocks since the pioneer days of Macculloch,
and Judd threw himself into the task with characteristic energy.
It was no light undertaking, for the area is large, much of the
ground is not easily accessible, and no good topographical maps
were then in existence. As the result of his investigations, he was |
led to regard the volcanic rocks of the Inner Hebrides as the
products of five great volcanoes, the much-eroded cores of which
are now represented by the chief plutonic complexes of the region.
He recognized further a certain succession in time among the
voleanic rocks, acid lavas and agglomerates being succeeded by
basic. If those who have followed him in the same field, working
under more advantageous conditions, have not confirmed all his
conclusions, they have still recognized their great indebtedness to
him who led the way. His results will remain an important con-
tribution to the ultimate solution of the problem, as well as a
memorable example of a generalization boldly conceived and
laboriously worked out.

The memoir which was the outcome of these researches, published
in the Quarterly Journal of the Geological Society in 1874,
attracted the notice of some of the leading geologists of the day,
and in this way the author made the acquaintance of Sir Charles
Lyell and Scrope, and later also of Darwin. The friendship and
encouragement of these veterans was of great value to the younger
man. It was under Scrope’s auspices that he enlarged: his know-
ledge of voleanic phenomena by visits to the active and extinct
voleanoes of Italy, Hungary, and Bohemia, the results of which

vat al

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. lix

Were seen in a series of papers published in the ‘ Geological Maga-
zine.’ In the course of these studies he was led to consider more
closely the nature of igneous action, and at this time also he first
formed that conception of different ‘ petrographical provinces’
which has since proved so fruitful.

The turning-point of Judd’s career came in 1876, when he was
chosen to succeed Ramsay as Professor of Geology in the Royal
School of Mines. The School was then housed in Jermyn Street,
but a little later the Geological division was removed to South.
Kensington, where it subsequently became part of the Royal
College of Science. Advised by Huxley, and profiting also by
what he had seen in Continental schools of geology, the new
Professor built up a thorough and comprehensive system ot
instruction, in which the practical element occupied a prominent
place. His own extensive knowledge and organizing talent, with
the help of a succession of able assistants of his own training, soon
placed the Royal College of Science in the foremost rank as a
training-school for geologists. The cordial relations which he
always cultivated with his students did not cease when they passed
out of his class, and many geologists at home and abroad still hold
the Professor in grateful remembrance.

His professorial engagements did not, however, preclude other
interests. In 1865 he had been elected a Fellow of this Society,
and in 1878 he had become one of its Secretaries, which office he
held until his election to the Presidency eight years later. In
the same year, too, he had married Jeannie Frances Jeyes, a
niece of the Midland geologist Samuel Sharp. Opportunities for
field-work were now more restricted; but, besides carrying out
a revision of the Tertiaries of the Hampshire Basin, he found
time to revisit the Western Isles and to make there a large
collection of the igneous rocks. With this material he entered
upon a new line of research, and in the years following he produced
a series of petrographical memoirs remarkable for their originality
and breadth of view. It was more particularly for this work that
he received in 1891 the award of the Wollaston Medal; but many
other subjects from time to time engaged his attention, and it is
impossible in a short notice to do justice to the long list of his
published works, showing an activity which embraced almost every
branch of geology. |

After his retirement in 1905, though his pen was not idle, his
energy began to suffer from the state of his health. A partial

Ix PROCEEDINGS OF THE GEOLOGICAL socrery. [ vol. xxii,

deafness cut him off from social intercourse, but infirmity did not
impair the genial temper, the quiet helpfulness and consideration
for others, which endeared him to his friends. During the last
year of his life he suffered from a nervous malady, under which he
gradually sank, and he died at his residence at Kew on March 3rd,
1916, a fortnight after his 76th birthday.!

JoserpH Henry Cotrtys died on April 12th, 1916, aged 75,
after a long life devoted to the study of the geology, mineralogy,
chemistry, and metallurgy of Cornwall and the Cornish ore-deposits.
Among his numerous scientific writings may be mentioned his
‘Handbook to the Mineralogy of Cornwall & Devon’ (1871) ;
‘The Hensbarrow Granite District’ (1878); ‘ Cornish Tin-Stones
& Tin-Capels,’ issued in 1888 as a revised edition of papers pre-
viously communicated to the Mineralogical Society ; and a memoir
‘On the Origin & Development of Ore-Deposits of the West of
England,’ published in the Journal of the Royal Institution of
Cornwall, 1890-95. He was a well-known figure in Cornwall,
where he was associated with all the local scientific societies. He
received the Henwood Medal of the Royal Institution of Cornwall
in 1898, and the Bolitho Medal of the Royal Geological Society of
Cornwall in 1898. He was elected a Fellow of this Society in
1869, and contributed to its Quarterly Journal a number of papers
dealing with Cornish geology and with Canadian metalliferous
deposits.

CHarLES THomas CrLouGH was born on December 28rd, 1852,
at Huddersfield, where his father held the office of Town Clerk.
From school at Rugby he passed to St. John’s College, Cambridge,
and, after graduating in 1874 in the first class of the Natural
Sciences Tripos, joined the Geological Survey. He began work in
Teesdale, and his first original production was a paper on the
section at High Force, read before this Society in 1876. Later he
was engaged in the Cheviot district, and in 1884 he was transferred,
with other members of the staff, from the English to the Scottish
branch. The detailed investigation of the North-West Highlands
was then beginning, and in this work Clough was soon taking an
important part. He was responsible for a portion of the critical

' I have borrowed largely from appreciative notices in the ‘ Geological
Magazine’ for 1905 and 1916.

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixi

area in West Sutherland and also for the Loch Maree district. In

the spring, when the mountains were not yet clear of snow, and in
the autumn, when the deer-forests were closed, he was engaged in

the Cowal peninsula of Argyllshire. Later he surveyed much

difficult ground in the Glenelg district, the south-eastern part of
Skye, and Haster Ross.

In 1902 Clough was made a District Geologist, and soon after-
wards took over the charge of the Survey work in Northern
Argyllshire and the Isle of Mull, while he was occupied during
the spring and autumn with the revision of the Scottish coal-fields.
It was in the course of this latter work that he met his death,
being run over in a railway-cutting, and sustaining injuries to
which he suecumbed three days later, on August 27th, 1916.

Clough was essentially a geological mapper, and, whether for
skill in unravelling complicated structures, or for minute and
accurate detail, his maps have probably never been equalled. Of
the numerous official memoirs of which he was author or joint-
author the most important are his parts of ‘The Geology of
Cowal,’ published in 1897, and ‘The Geological Structure of the

_ North-West Highlands,’ issued ten years later. His writings are

characterized by scrupulous accuracy concerning the facts of
observation, combined with a conscientious care in the drawing of
conclusions. The reader soon acquires the conviction that any
statement advanced by Clough may be accepted without hesitation.

While deeply absorbed in his geological work, he took also a
keen interest in social questions. His personal tastes and habits
were of the simplest. His gentle nature, his transparent sincerity,
his modesty concerning his own work, and his generous apprecia-
tion of that of others, gave him a warm place in the hearts of all
who knew him. In 1906 he received recognition from this Society
in the form of the Murchison Medal; from 1908 to 1910 he was
President of the Geological Society of Edinburgh; and only a
month before his death the University of St. Andrews conferred
upon him the degree of LL.D. He leaves a widow with one son
and two daughters.

By the death of CremENT ReErp we have lost an assiduous
worker who, during a Fellowship of forty years, has done much to
forward the interests of the Society, both by his scientific contri-
butions and by his services on the Council. The value and promise
of his work were recognized by the award to him of the Murchison

Ix PROCEEDINGS OF THE GEOLOGICAL SOCIETY. { vol. lxxiu,

Fund in 1886 and of the Bigsby Medal in 1897. He was elected
into the Royal Society in 1899. He served on our Council in
1892-95, and again in 1912-16, being a Vice-President for the
last three of these years. He also served on the Council of the
Linnean Society. |

Born on January 6th, 1853, Reid had the investigator-strain in
his blood, being a great-nephew of Michael Faraday. He owed
little to early training, for circumstances compelled him to enter
business while still a youth; but the nascent spirit of research
was stirred in him at the Juvenile Lectures of the Royal Institu-
tion, and he set out courageously to qualify himself for a scientific
career. Overcoming all difficulties, he obtained in 1874 a post on
the Geological Survey as Assistant-Geologist, and entered with
‘enthusiasm upon what was to be his life’s work. After a short
spell in the South-West of England, his duties took him to the
Eastern Counties and to the investigation of the complicated
Pliocene and Pleistocene deposits of the Norfolk coast, a task in
which he quickly proved’ his ability both as geologist and as
naturalist. In the course of this work he devoted special attention
to the discovery and identification of the seeds of plants contained
in some of the deposits. This branch of research he afterwards
continued to pursue with conspicuous success, and became recog-
nized as a leading authority on the subject among Continental as
well as British geologists.

Reid was next engaged on the north-eastern moorlands of York-
shire, and afterwards in Holderness and East Lincolnshire. Later
he was sent to map the South Downs and the coastal tract of
Sussex, passing thence through Hampshire and part of the Isle of
Wight into Dorset and Wiltshire. His descriptions of these areas
are contained in a series uf official memoirs published between the
years 1882 and 1903, and they are characterized, as are all his
writings, by clarity of expression and a grip of essentials. Mean-
while he had produced also a general monograph on the Pliocene
deposits of Britain, during the preparation of which he paid visits,
for purposes of comparison, to Belgium and Italy. His researches,
however, never stopped at the bounds of his official duty: all his
leisure was spent in furthering the studies which he had at heart,
and he was ever ready to bestow time and pains in helping any
other worker who stood in need of his special knowledge. His
papers contributed to scientific societies and periodicals were many,
and cover a wide range of subjects, but especially the plant-life

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ix

of the later geological periods, the climatic conditions indicated by
various kinds of deposits, and questions relating to the early history
of Man in this country. By their subject-matter and the able
manner of its presentment some of these papers have taken a
standard place in geological literature.

In 1897 Reid married Miss Eleanor M. Wynne Edwards, who
took an active share in most of his later work. In 1899 he summed
up his knowledge of the botanical conditions of the past in a book
entitled ‘The Origin of the British Flora,’ which appealed equally
to geologists and to botanists; and later, in 1918, he dealt in the
same way with the subject of our ‘Submerged Forests.’ After
his promotion in 1901 to the rank of District Geologist, he was in
charge of the Survey work in the difficult area of Cornwall and
Devon. This was completed in 1909, and the results are recorded
in memoirs written in conjunction with his colleagues. It was in
recognition of this work that Reid received the Bolitho Medal of
the Royal Geological Society of Cornwall. In 1908 he made a
visit to Cyprus, for the purpose of advising the Colonial Office on
matters connected with the water-supply of the island. From
1909 until his retirement from official life early in 1913, he had
charge of the survey of the area round London.

Freed from the trammels of office, Reid left London for the
quiet of a new home at Milford-on-Sea, on the borders of the New
Forest, where he concentrated his energies upon paleobotanical
_ researches. Among other studies, he made, in collaboration with
his wife, a thorough examination of the interesting plant-fossils
from Holland, which were described in a series of joint papers
upon the Pliocene flora of the Dutch-Prussian border. He also
began with Mr. J. Groves a promising investigation of the fossil
Characez, some of the first results of which were brought before
this Society only a few weeks ago. But the check came when he
was in full career, with every prospect of further achievement.
He died after a short illness, and without much suffering, on
December 10th, 1916.

Clement Reid’s sincerity of mind and unswerving devotion to
the pursuit of knowledge were apparent to all who knew him.
_ His writings constantly evince a sense of the imperfection of our
present attainment and the ‘tentative character of the results
-achieved. Always he lays stress upon the need for more facts, and
avoids the temptation to round off artificially the work already
done. In his outlook he was essentially a naturalist, and he

lxiv PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [vol. Ixxiii,

deprecated any attempt to solve the problems of the earth’s past
from geological data alone. He persevered to the end in his
self-appointed task, and his latest thoughts were still for his
work. [Ge Westies

The death of Beprorp McNerit, at the age of 55, takes from
us a prominent exponent of Applied Geology, and deprives the
Society of a valued officer. Trained at the Royal School of Mines,
Jermyn Street, he entered upon his profession of mining engineer
in 1880, and was employed to inspect and report on mines in
Mexico, Colorado, and other parts of the world. Settling later
in London, he became consulting engineer to a number of important
mining companies, and attained a leading place in the profession.
In the year 1913-14 he was President of the Institution of Mining
& Metallurgy, and his Address on that occasion showed that he
held high views as regards the importance of geological science in
relation to all mining undertakings. His intervals of leisure were
employed during many years in compiling the Telegraphic Code
which has made his name widely known, a work of much careful
labour, which was first issued in 1893, and was revised and enlarged
in 1908.

Bedford McNeill had become a Fellow of this Society in 1888.
He served on the Council in 1904-1907, and at the time of his
death had held for four years the important office of Treasurer.
His loss is deplored by a large circle of friends, to whont his happy
disposition and genial humour rendered him always welcome. He
died at his residence at Claygate (Surrey), after a short illness,
on September 18th, 1916, leaving a widow but no family.

CHARLES Barrineton Brown was born at Cape Breton (Nova
Scotia), and educated at Harvard University and at the Royal
School of Mines in Jermyn Street. His father, Richard Brown,
author of several papers on Cape Breton in the early volumes of our
Quarterly Journal, was a close friend of Sir Charles Lyell, and it
was through Lyell that the younger Brown was appointed to the
Geological Survey of the West Indies (Jamaica) and of British
Guiana. The results of this work are contained in valuable reports,
written in conjunction with J. G. Sawkins and published in 1869
and 1875. Brown was an explorer as well as a geologist. In 1870
he discovered the famous Kaieteur Falls on the Potaro River in
British Guiana, and between 1873 and 1875 he travelled 15,000

eee ee ee fe

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixv

miles on the Amazon and its tributaries. Later he was engaged
chiefly in the exploitation of gem-stones in Burma, North Carolina,
_ Ceylon, and New South Wales; and in particular his memoir on

the rubies of Burma, written in collaboration with Prof. Judd, was
an important contribution to the natural history of corundum.

By the testimony of those who knew him best, Barrington
_ Brown’s success as an explorer was made possible by personal
qualities which endeared him to men of all kinds, and especially by
an evident sincerity which caused him to be universally trusted.
Tn his later years he suffered from the effects of fevers contracted
during many tropical journeys, but he had reached his seventy-
eighth year when he died on February 18th, 1917. He had been
a Fellow of this Society since 1879.

Henry Rosaes, probably the oldest Fellow on our list, in
which his name first appeared in 1877, was well known as a
geologist and mining engineer in Victoria for more than sixty
years. Born in Spain, he received his training at Freiberg, and
went out to Australia, where he was engaged on the Ballarat and
other gold-fields of Central Victoria. His first communication
to this Society was made in 1855, and he was the author of
numerous contributions to mining journals and to the publica-
tions of the Geological Survey of Victoria. He also made a
valuable collection of minerals, which he presented to the Uni-
versity of Melbourne. Retiring from professional life thirty years
ago, he continued to take an interest in geological and mining
problems, and retained to the last his keen intellectual faculties.
He died at Melbourne in May, 1916, aged 94.

Watrer Epwarp Kocx was born on March 19th, 1848, and
was educated at Marlborough, at King’s College, London, and at
St. John’s College, Cambridge. He adopted the profession of
mining engineer, and for the last thirty years of his life was
engaged in mining work in various parts of America. He became
a Fellow of this Society in 1869, and, though he did not contribute
to our Journal, always preserved his interest in geology as well as
chemistry. At the time of his death he had in hand a series of
experiments on the effects produced in rocks at high temperatures.
He died on May 25th, 1916, at El Paso (Texas), where he was
manager of the famous quicksilver-mines of Terlingua.

VOL. LXXITI. é

Ixvi PROCEEDINGS OF THE GEOLOGICAL society. [ vol. lxxin,

Frank FowteEr, who died on January 16th, 1917, aged 53, was
a well-known Government official in British Guiana. There he
was born and educated, and his life was spent in the Civil Service
of the Colony. At the time of his death he had filled for fourteen
years the office of Commissioner of Lands and Mines. He was
elected into this Society in 1910.

CuHartes Dawson, though born in Lancashire, passed most of
his life in Sussex. There, while following the profession of solicitor,
he found time to gratify his interest in geology and archeology.
He devoted much attention to the reptilian remains in the Wealden
formation, and made a valuable collection, which is now deposited
in the British Museum (Natural History). Later he was attracted
to the study of prehistoric man, and his name became widely
known in connexion with his discovery of the Piltdown skull.
Of this, with Dr. Smith Woodward as coadjutor, he communi-
cated an account to our Society in December, 1912. He died at
Lewes, after a protracted illness, on August 10th, 1916. He had
been a Fellow of our Society since 1885.

THomas DE Courcy Mraps, who died on February 13th, 1916,
had held since 1894 the post of City Surveyor at Manchester.
There his most important work was done in connexion with the
new drainage scheme of the city, on which he read a paper to the
Engineering Section of the British Association in 1915. He was
elected a Fellow of this Society in 1891, and was also a member of
the Institutions both of Civil and of Mechanical Engineers.

Lastly, we have to lament the premature death of five of our
younger Fellows, who have fallen while fighting for their country
and for the cause of civilization. RerernaLtp CooxsEy Burton,
Assistant-Superintendent on the Geological Survey of India,
attached to the 104th Rifles in Mesopotamia, was wounded in
action on April 8th, 1916, and died on the following day, aged 26.
During three years of service in India he had done good work,
especially in connexion with the gneisses of the Central Provinces
and the origin of the Seoni bauxites; and the Director of the
Survey describes him as ‘one of the most promising, as well as one
of the most popular, of its younger members.’ Ricnuarp Roy
Lewer, Lieutenant in the King’s Royal Rifles, eldest son of
Mr. H. W. Lewer, of Priors, Loughton (Essex), was wounded on

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixvu

July 15th, 1916, on the Western Front, and died six days later,
aged 26. He had already done useful work in the oil-fields of
Burma, Russia, and Western Canada. ARCHIBALD WILLIAM
Ropertrson Don, Lieutenant in the Black Watch, fourth son of
Mr. R. B. Don, of Tealing House (Forfarshire), died in hospital
in Greece on September 11th, 1916, aged 25. The keen interest
in Geology which he had shown as an undergraduate at Cambridge
was not lost when he quitted the University to enter the medical
profession, and his researches on Parka decipiens seemed to hold
the promise of much good work in the future. James CowrE
Simpson, Lieutenant in the Royal Engineers, eldest son of the
late Mr. Watson Simpson of Edinburgh, was killed in action on
December 4th, 1916, aged 31; and RatpH Hawrrey, also a
Lieutenant in the Royal Engineers, son of the late Mr. Montagu
Hawtrey, of Shanghai, was killed in action on September 8rd,
1916.

Some Aspects oF IGNEOUS ACTION IN BRITAIN.

Ir has often been pointed out that, for so small an area, the strati-
graphical record in Britain is a remarkably varied one, bearing
witness to many vicissitudes of physical conditions in this part of
the earth’s surface. To this may be attributed in some measure
the lead which British workers-have so often taken in the develop-
ment of stratigraphical geology. It is equally true that the record
of igneous activity in our area is full and varied to an extent not to
be paralleled elsewhere. Whether here also we have always lived
up to our privileges I will not now enquire, but it will be granted
that in the last quarter of a century, at least, much valuable work
has been done in this field. In this revival of interest, shown both
on the Geological Survey and among individual workers, we can
trace especially the influence of Sir Archibald Geikie. ‘The masterly
account of igneous action in Britain, which he gave from this
Chair in 1891-92, was expanded subsequently to the compass of
two large volumes, but it would to-day need to be much further
amplified in order to include the results of later researches. I must
be content to choose a single aspect of this large subject, and
I propose to consider it from the point of view of the relation

between igneous action and crust-movements. The link
| e2

Ixvul PROCEEDINGS OF THE GEOLOGICAL SociETy. [vol. lxxiu,

connecting these two classes of effects is found in the consideration
that both afford relief to the unequal stresses which are continually
being set up in the earth’s crust by causes regional as well as
cosmic.

To enquire into ultimate causes is no part of my design. Mellard
Reade showed long ago how mountain-building movements result
from prolonged sedimentation in a slowly subsiding geosynclinal
basin, but the general problem seems to involve also other factors.
There is in the greater orogenic displacements an element of uni-
lateral progression, which leads us to picture them in imagination
as gigantic waves. In the broad structure of Europe we see the
results of four successive earth-waves of the largest order, all
advancing in a general sense from the south. The actual belts
of folding, as laid down on a map, show sweeping curves, with a
certain amount of interlocking. At one place only do three of
these belts come together within a relatively narrow space, and it is
precisely in this significant situation that the British Isles he.

The unique advantages enjoyed by British geologists, to which I
have adverted, result then from the fact that three systems of crust-
movements, at widely separated epochs, the Lewisian, the Cale-
donian, and the Hercynian, have all contributed to the building of
ourcountry. Moreover, the whole history of Britain can be viewed
in relation to these cardinal events, and only when so regarded
appears as a coherent sequence. Especially is this true of igneous
action, since fluid, or partly fluid, or potentially fluid, rock-material
is necessarily more responsive to changes in stress-conditions than
the solid crust itself. Accordingly, each great system of crust-
movement has been attended by a display of igneous activity,
related to it ina manner which clearly bespeaks some underlying
law of causation. There is in each case evidence of extensive
plutonic intrusion within the disturbed area, either at the crisis of
the disturbance, or following it after no long interval by geological
reckoning. These copious intrusions of magma, no part of which
reached the surface, are not only events of the first magnitude, but
seem to differ functionally from the igneous action which charac-
terizes other stages of the cycle. This more diffused activity,
taking the form of extrusion as well as intrusion, is developed
during the gathering of crustal stress before the critical epoch, and
again especially in the later waning stages. It has many features
suggesting that the several episodes which can be distinguished
have their proper places in an ordered sequence. When there has

part 1] § ANNIVERSARY ADDRESS OF THE PRESIDENT. lxix

been igneous action during a season of relative quiescence, this too
has its own significant characteristics.

We shall not, however, appreciate fully the relation between
igneous action and crustal stress, unless we have regard also to the
petrographical facies of the rocks erupted at different phases of a
complete cycle. It is becoming increasingly evident that magmatic
differentiation is closely bound up with progressive crystallization,
the essential factor being a separation, or partial separation, effected
between the crystalline and the fluid portions at one stage or
another of the process. Thanks to the researches of the Washington
chemists, this doctrine now rests upon a basis of laboratory experi-
ment, and Dr. Bowen has recently put forward a general theory of
primary differentiation founded upon this direct evidence. The series
of successive ‘ fractions’ begins with terms rich first in magnesian
and next in calcie silicates, and shows then a steady increase both
in alkalies and in silica. So far this agrees with what has been so
often observed in a series of related plutonic intrusions, following
one another in an order of increasing acidity with falling tempe-
rature. Bowen shows, however, that a rock rich in alkali-felspars
and free silica need not represent the final term. The continued

concentration of water and other gases in the residual magma gives

rise in the later stages to hydrolysis and analogous reactions, by
which the progress of crystallization is much modified. This
appears in the formation of orthosilicate micas in the presence of
free silica, and finally in the production of nepheline and other
basic alkaline silicates at the expense of the albite molecule. The
differentiation-series is thus extended by the addition of new terms,
still increasingly rich in alkali, and specifically in soda, but now
with a diminishing content of silica. The empirical law of in-
creasing acidity must therefore be replaced by one of increasing
alkalinity. An ideal complete series would begin with an ultra-
basie type. such as a peridotite, devoid of alkali, and end with
another ultrabasic type, such as an ijolite, very rich in alkali.

This doctrine, for which much geological as well as chemical
evidence can be adduced, throws an interesting new light upon the
mutual relations of igneous rocks. For my present purpose it is

‘sufficient to emphasize the general rule to be deduced from it. If

at any stage of progressive crystallization, or progressive fusion, a
separation or partial separation is brought about between the fluid
and the crystalline part, the former will be relatively rich in alkali,
and particularly in soda, while the latter reciprocally will be rich in

Ixviil PROCEEDINGS OF THE GEOLOGICAL society. [vol. xxi,

connecting these two classes of effects is found in the consideration
that both afford relief to the unequal stresses which are continually
being set up in the earth’s crust by causes regional as well as
cosmnic.

To enquire into ultimate causes is no part of my design. Mellard
Reade showed long ago how mountain-building movements result
from prolonged sedimentation in a slowly subsiding geosynclinal
basin, but the general problem seems to involve also other factors.
There is in the greater orogenic displacements an element of uni-
lateral progression, which leads us to picture them in imagination
as gigantic waves. In the broad structure of Europe we see the
results of four successive earth-waves of the largest order, all
advancing in a general sense from the south. The actual belts
of folding, as laid down on a map, show sweeping curves, with a
certain amount of interlocking. At one place only do three of
these belts come together within a relatively narrow space, and it is
precisely in this significant situation that the British Isles he.

The unique advantages enjoyed by British geologists, to which I
have adverted, result then from the fact that three systems of crust-
movements, at widely separated epochs, the Lewisian, the Cale-
donian, and the Hereynian, have all contributed to the building of
ourcountry. Moreover, the whole history of Britain can be viewed
in relation to these cardinal events, and only when so regarded
appears as a coherent sequence. Especially is this true of igneous
action, since fluid, or partly fluid, or potentially fluid, rock-material
is necessarily more responsive to changes in stress-conditions than
the solid crust itself. Accordingly, each great system of crust-
movement has been attended by a display of igneous activity,
related to it in a manner which clearly bespeaks some underlying
law of causation. There is in each case evidence of extensive
plutonic intrusion within the disturbed area, either at the crisis of
the disturbance, or following it after no long interval by geological
reckoning. These copious intrusions of magma, no part of which
reached the surface, are not only events of the first magnitude, but
seem to differ functionally from the igneous action which charac-
terizes other stages of the cycle. This more diffused activity,
taking the form of extrusion as well as intrusion, is developed
during the gathering of crustal stress before the critical epoch, and
again especially in the later waning stages. It has many features
suggesting that the several episodes which can be distinguished
have their proper places in an ordered sequence. When there has

part 1] = ANNIVERSARY ADDRESS OF THE PRESIDENT. lxix

been igneous action during a season of relative quiescence, this too
has its own significant characteristics.

We shall not, however, appreciate fully the relation between
igneous action and crustal stress, unless we have regard also to the
petrographical facies of the rocks erupted at different phases of a
complete cycle. It is becoming increasingly evident that magmatic
differentiation is closely bound up with progressive crystallization,
the essential factor being a separation, or partial separation, effected
between the crystalline and the fluid portions at one stage or
another of the process. Thanks to the researches of the Washington
chemists, this doctrine now rests upon a basis of laboratory experi-
ment, and Dr. Bowen has recently put forward a general theory of
primary differentiation founded upon this direct evidence. The series
of successive ‘ fractions’ begins with terms rich first in magnesian
and next in calcie silicates, and shows then a steady increase both
in alkalies and in silica. So far this agrees with what has been so
often observed in a series of related plutonic intrusions, following
one another in an order of increasing acidity with falling tempe-
rature. Bowen shows, however, that a rock rich in alkali-felspars
and free silica need not represent the final term. The continued
concentration of water and other gases in the residual magma gives
rise in the later stages to hydrolysis and analogous reactions, by
which the progress of crystallization is much modified. This
appears in the formation of orthosilicate micas in the presence of
free silica, and finally in the production of nepheline and other
basic alkaline silicates at the expense of the albite molecule. The
differentiation-series is thus extended by the addition of new terms,
still increasingly rich in alkali, and specifically in soda, but now
with a diminishing content of silica. The empirical law of in-
creasing acidity must therefore be replaced by one of increasing
alkalinity. An ideal complete series would begin with an ultra-
basie type. such as a peridotite, devoid of alkali, and end with
another ultrabasic type, such as an ijolite, very rich in alkali.

This doctrine, for which much geological as well as chemical
evidence can be adduced, throws an interesting new light upon the
mutual relations of igneous rocks. For my present purpose it is
‘sufficient to emphasize the general rule to be deduced from it. If
at any stage of progressive crystallization, or progressive fusion, a
separation or partial separation is brought about between the fluid
and the crystalline part, the former will be relatively rich in alkali,
and particularly in soda, while the latter reciprocally will be rich in

Ixx PROCEEDINGS OF THE GEOLOGICAL Society. [vol. Ixxiu,

lime and magnesia. As regards the mechanism of such separation,
Bowen lays stress especially upon the sinking of crystals in a mass
which is still mainly liquid. Simple physical considerations, how-
ever, tell us that a great liquid or mainly liquid reservoir within
the earth's crust can have only a temporary status. It is doubtless
incidental to the existence of much more extensive tracts of the
lower crust in a semi-liquid state, that is, as a liquid crowded with
crystals or a crystalline fabric with interstitial liquid. Such a
condition must be postulated beneath any region which is the
theatre of long-continued igneous activity, and a mass so constituted
possesses remarkable properties. In particular, it is very sensitive
to unequally distributed stress, the liquid part tending to be driven
from places of greater to places of less stress. When in such a
region an unequal distribution of crustal stress is maintained sufh-
ciently long, there will be a continued flux of the interstitial
magma, which will be driven out from areas of special disturbance
to accumulate beneath areas of relative quiescence. If, in addition
to this lateral displacement, the magma works its way into the
upper crust or to the surface, highly alkaline rock-types may result.
Otherwise, and more generally, the magma so displaced will go to
impart a more or less marked richness in alkali to the crust beneath
the undisturbed areas, and the effect may be seen only at some later
epoch and in a less extreme manifestation.

The doctrine of two classes of igneous rocks, alkalene and calcic,
having a significant geographical distribution in relation to the
great tectonic features of the globe, has, then, a certain justification.
It does not, of course, imply any sharp division; and perhaps the
more philosophical conception is that of two opposite petrographical
poles, towards which igneous rocks tend as a result of primary
differentiation. There is naturally some complication introduced
by subsequent processes, giving rise to the great diversity of igneous
rocks known to petrographers ; and these later processes may some-
times obscure, as regards individual rock-types, the primary
characteristics.

To illustrate these general remarks, and to put to the test the
element of hypothesis which they contain, I propose to recall
rapidly the leading events in the igneous history of the British
area. We are met at the outset by a difficulty which arises from
lack of full knowledge. There is only one part of the country,
namely: the Scottish Highlands, where any large expanse of the

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxi

oldest rocks can be seen, and much study of that difficult region has
left some fundamental questions still unsettled. It is not yet a
matter of common agreement whether the ‘Older’ Gabbros and
Granites of the South-Eastern Highlands belong to the same
epoch as the Lewisian of the North-West, or to a distinct and much
later epoch.

Leaving this question and others for future solution, we may note
meanwhile some very instructive features of these ancient plutonic
intrusions. The rocks are of calcic facies, like all other rocks
intruded in close connexion with powerful lateral thrust. In this
case the connexion 1s of the closest possible kind. In the South-
Hastern Highlands especially it is clearly seen that the earliest
intrusions of magma preceded the climax of the disturbance, so that
the basic members of this rock-series met the brunt as rocks already
solid; while the later and more acid magmas were intruded near
the height of the mechanical disturbance, and during its decline.
The further circumstance that the region was long maintained at a
high temperature had an interesting consequence ; for the straining-
off process, which I have pictured as taking place in the deeper
erust, was here effected at a level which is now exposed to view.
How in this way broad fringes of pegmatite have been squeezed out
from the half-consolidated granites has been well described by
Mr. George Barrow. The pegmatites are often rich in microcline
and muscovite, but this is the limit of their approach towards the
alkaline pole. It is instructive to compare these Scottish Archean
granites with those which build the great Laurentian batholites of
Lower Canada, intruded under very different mechanical conditions.
There we find a fringe of albite-granite, albite-syenite, and finally
nepheline-syenite and ijolite. The close synchronism of the British
Archean intrusions with powerful lateral thrust finds a parallel,
however, in many other parts of the world, and the fact is of prime
importance in relation to the crystalline schists. The older sedi-
ments were recrystallized under the influence of great stress as well
as high temperature, a conjunction not realized on the same exten-
sive scale at any subsequent period.

What has been remarked of the ‘ Older’ plutonic intrusions of the
South-Eastern Highlands seems to be true also in the main of the
Lewisian series, assigned on the view most widely held to an earlier
epoch, and so to an earlier system of crust-movement. Erosion,
however, has exposed lower levels in the North-West, and thus has
presented us with a different aspect of the igneous economy. In

Ixxil PROCEEDINGS OF THE GEOLOGICAL SoOcrIEry. [ vol. lxxiu,

particular, the more basic members of the series are much more in
evidence, as also the invasion of these by the later acid rocks with
resultant intermingling and hybridism. j

Time does not permit me to do more than mention the Archzean
crystalline rocks of North-Western Ireland, of Central Anglesey,
of Malvern and the Wrekin, and of the English Channel tract. I
pass on to the Dalradian Series, belonging on the more generally
accepted view to some time between the Lewisian crust-movements
and those to which the ‘Older Granites’ of the South-Eastern
Highlands were related, but on Mr. Barrow’s reading older than
the one. great Archean system of mountain-building in that
region. Whatever may be their chronological relations, 1t appears
that these ancient sediments, now so highly disturbed, were laid
down in a basin which was undergoing a slow subsidence but no
movement of the nature of folding. This is to be inferred from
the extension of the series and the persistence of the same types of
sediment over wide areas. Contemporaneous igneous action is
indicated, on no great scale, but of very distinctive type. Specially
characteristic are the spilite-lavas in the Loch Awe group of Knap-
dale, with their associated intrusions of albite-dolerite and soda-
felsite. If the spilites seen in North Glen Sannox (Arran) are in
their original relations, which I see no reason to doubt, they afford
evidence of similar eruptions ata lower horizon. The ‘pillow-lavas’
and associated volcanic rocks of County Tyrone were likewise
referred by Sir Archibald Geikie to a Dalradian age, and, although
he has retracted this opinion, the materials for a final judgment
are still to be gathered. Probably to this age, and certainly to a
very early pre-Cambrian epoch, belong the ‘Green Rocks’ studied
by Mr. Greenly in Anglesey and by Dr. Matley on Bardsey and the
coast of Lleyn. These reproduce the same characteristic types,
both effusive and intrusive.

The oldest volcanic rocks in Britain have, then, a common petro-
graphical facies, and with them are associated intrusive rocks also
of certain well-defined types. The chief characteristic of the whole
is a richness in sodic felspars. Mr. H. Dewey & Dr. J. 8S. Flett have
shown that the same association of rock-types recurs in the British
area at several later epochs, and they consider that it is peculiar to
‘ districts that have undergone a long-continued and gentle subsidence, with
few or slight upward movements, and no important faulting.’

In several parts of Wales and the English Midlands we have
evidence of igneous activity at a much later period of pre-Cambrian

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. xxii

history. Although there are no data for correlating the rocks of
the isolated areas, it is clear that they all belong to a time when
the main Archzan crust-movements were past. It does not follow
that the conditions as regards crustal stress were the same in
the several districts, and the observed petrographical differences are
probably not without significance. In Pembrokeshire there seems
to be no noteworthy break between the volcanic series and the
succeeding Cambrian, and indeed the basic intrusions which repre-
sent the latest igneous episode sometimes penetrate the Lower
Cambrian strata. The old lavas and tuffs here have been studied
only in part, but soda-rhyolites seem to be the most characteristic
type. The associated intrusions in the Brawdy and St. David's
districts, as described by Dr. H. H. Thomas & Prof. O. T. Jones, |
include especially albite-granites, and the plutonic complex of
Johnston is also composed of rocks rich in sodic felspars. In this
area, not affected by any contemporaneous disturbance, the rocks
have, then, a pronounced alkaline facies. Herein they differ from
the probably homotaxial rocks of the Wrekin and Malvern, Bangor
and Llanberis, areas which lay close to centres of Lewisian in-
trusion, and were perhaps still under the influence of special stress.

With the Paleozoic era we enter upon a time concerning which
we possess much fuller information. Some leading features of the
broad stracture of our country were already roughly blocked out,
and have exerted a dominant influence upon subsequent events. To
the north-west was the large crystalline mass of which the Scottish
Highlands and North-Western Ireland are relics, consisting of great
plutonic cores with their aureole of metamorphosed sediments.
This, with a general north-easterly and south-westerly extension,
marks roughly one limit of the geosyncline in which our Lower
Paleeozoic strata were laid down. As regards the southern limit,
there are many indications of an important Archean tract on the
site of the English Channel; and it may well be that what we
regard as the Armorican trend was already impressed on the
southern part of the British area, as the Caledonian trend was on
the northern. The geosyncline thus bounded was not a simple .
one, but contained within it minor features, likewise of Archean
age, which continued to make their influence felt at later times.

During the deposition of the Cambrian and earlier Ordovician
sediments this area was undergoing a general subsidence. The
downward movement, however, was neither equable in extent nor

xxiv PROCEEDINGS OF THE GEOLOGICAL socrety. [ vol. lxxii,

uniform in rate, and was at times interrupted and locally reversed.
In particular, the Ordovician conditions were ushered in by differ-
ential vertical movements, which accentuated the geosynclinal
structure, defining more strictly the north-western border, pro-
bably tie southern too, and developing areas of relative elevation
in the interior, which were broadly of the nature of horsts. It
was about this time that igneous action was initiated, breaking out
in the marginal part of the basin, and affording relief to the
differential stresses which there attained their maximum.

Following upon a prolonged gentle subsidence, not complicated
by any movements indicative of lateral thrust, these early eruptions
had everywhere a pronounced alkaline, that is, sodic, facies. The
earliest, which broke out close to the actual borders, all belong to
the ‘spilitic series’ of Dewey & Flett. The predominant basic
lavas are typical spilites, and, if acid types occur, they are soda-
rhyolites with corresponding tuffs. The associated intrusive rocks
are of types constantly found in this connexion, such as albite-
dolerites and soda-granite-porphyries. Here comes the volcanic
series of which relics are found along the actual Highland Border,
especially in Forfarshire and Kincardineshire. The voleanic belt
is perhaps prolonged farther south-westwards, for to this series
Mr. Gunn has referred the North Glen Sannox spilites and Sir
Archibald Geikie the voleanic rocks of Tyrone. In Cornwall the
spilites of the Lizard and Gorran Haven seem to preserve relics of a
similar train of volcanic centres on the southern border of our area.
The age of the eruptions in these several districts cannot always be
fixed with precision. They are commonly referred to the Arenig,
but on the Highland Border at least they may, according to
Dr. Campbell, be Upper Cambrian.

From this narrow border-belt igneous activity shifted to a
wider belt lying somewhat within the border. The eruptions here
were on a grander scale. Dating from the Arenig, they continued
in some districts into part of Llandeilo time. In addition to the
spilitic series, the rocks of this submarginal belt include other types,
likewise characterized by richness in sodie felspars. Here belong in
the north the voleanic districts of the Southern Uplands of Scot-
land, extending from Girvan and Glenluce to the Muirfoot Hills
in Peebleshire, and in the west the Lower Paleozoic inliers of the
Lough Mask district, described by Prof. Reynolds & Mr. Gardiner.
It may be remarked that the plutonic complex of Girvan consists
of calcie types of rocks, and in the Irish district also the associated

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxv

intrusive rocks are only in part of strongly sodic nature. The
intrusions are of later date than the volcanic outpourings—some in
the Lough Mask area are post-Llandovery—and a change in the
stress conditions may be presumed. We shall see later that calcic
intrusive rocks may be found in closer relation with voleanic rocks
of alkaline nature, and that the seeming anomaly is in accordance
with the principles laid down.

In the south the submarginal belt of activity includes the
voleanic districts of Pembrokeshire, our knowledge of which has
been much enlarged in recent years. The lavas of Skomer Island,
described by Dr. H. H. Thomas, include a range from soda-rhyolites
through various types of soda-trachytes to mugearites and olivine-
basalts. To the same series we may probably refer the soda-
rhyolites of Trefgarn, near Haverfordwest, and perhaps the volcanic
group of Llangynog, near Caermarthen. This is described as
consisting of augite-andesites and rhyolites; but the former seem
to be of mugearitic rather than andesitic affinities, and so make no
exception to the general alkaline facies.

These various occurrences are probably all low down in the
Arenig; but those of North Pembrokeshire belong to higher hori-
zons, indicating a progressive displacement of the theatre of
activity towards the interior of the geosyncline. The ceratophyres
of Abercastle are intercalated in the Tetragraptus Beds, while the
soda-rhyolites and rhyolite-tuffs of Llanrian are in the upper part
of the Didymograptus-bifidus Zone, and the fuller development at
Fishguard is probably at about the same horizon. Here, in
addition to soda-rhyolites, Dr. Cox has recognized typical spilites.
They were succeeded by basic intrusions, mostly in the form of
irregular sills. In these the strongly alkaline nature is sometimes
less pronounced, but the dolerites of Fishguard have an oligoclase-
andesine as their dominant felspar, and the thick sills of St. David’s
Head, probably of the same series, show albitization.

In the interior of the British geosyncline late Cambrian and
early Ordovician eruptions were not wholly wanting, but they were
on a feeble scale, and were confined to the neighbourhood of areas
which had already acquired special tectonic importance. If any
outbreak occurred on the borders of the Archean horst of
Anglesey, the evidence of it has been lost. But the Harlech
anticline had already declared itself, perhaps as the reassertion of a
concealed Archzean centre, and on its skirts the first effects of
vuleanism were localized. The lavas in the Upper Lingula Flags

lxxvi PROCEEDINGS OF THE GEOLOGICAL society. [{ vol. xxi,

of Dolgelly are much albitized, and appear to be spilites. The
crystal-tuffs and agglomerates of Rhobell Fawr, immediately
underlying the base of the Ordovician, resemble those of the
Sanquhar district of Dumfries-shire, and will probably be found
likewise to have alkaline affinities. Later came the soda-rhyolites
of Dolgelly and Cader Idris, assigned by Mr. P. Lake & Prof.
S. H. Reynolds to a Lower or Middle Arenig age, and on the
other side of the Harlech dome Prof. O. T. Jones has noted spilite-
lavas in the Lower Arenig of the Lleyn.

So far, the only important crust-movements had been of the
nature of a slow subsidence. The igneous action connected with
the subsidence shows a certain symmetrical disposition relative to
the shape of the geosynclinal region, and the general alkaline
nature of the igneous rocks is significant in the same sense.
Towards the close of the Arenig age, however, a change in all these
conditions begins to be evident. It is clearly related to the coming
in of a certain element of lateral thrust, a premonition of that
which attained a much greater intensity at a later time. The
symmetry of arrangement gave place to a decided unilateral
disposition. By the accentuation of old features and the develop-
ment of some new ones, the original geosyncline came to be divided
into areas which can for many purposes be considered separately,
and in each of them the unilateral factor, related to a thrust
coming from the south or south-east, is apparent. The vigorous
outbreak of igneous activity which ensued was comprised mainly
in Llandeilo time, and its products are found to differ significantly
from those of the earlier eruptions, the spilitic series giving way
largely to the andesitic.

I will consider especially the Welsh part of the region, since
there our information is relatively full. It was in some measure
isolated by the presence, on what may be termed its ‘ lee side,’-of
the old massif of Anglesey. In front of this, as we now see it,
and having the same north-easterly and south-westerly direction,
are the two parallel ridges in which the younger pre-Cambrian rocks
emerge, one extending from Bangor to Caernarvon and the other
passing near Llanberis. The initiation of these ridges seems to
have been an early consequence of the slowly gathering thrust,
and they played the part of outworks to the Anglesey barrier. A
broader uplift, with the same Caledonian trend, was developed
through Shropshire and Radnorshire, and, though too gentle an
undulation to act as a buttress, probably had its influence on the
distribution of eruptions in the area.

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxvil

The widespread vuleanicity of Arenig times in South Wales
had died out, and the new theatre of activity lay farther north.
Eruptions broke out on the flanks of the new central anticline,
both in Radnorshire and in Shropshire. In Merioneth the vul-
eanicity, prolonged through the whole of Llandeilo time, was on a
larger scale. It is represented by a great thickness of fragmental
accumulations, together with andesitic sills which, as Prof. Fearn-
sides has shown, were closely bound up with the volcanic episode.
In Caernarvonshire, in addition to explosive outbursts, there was a
great outpouring of lavas. The district there affected, centreing
in Snowdonia, extends in one direction beyond Conwy and in the
other into the Lleyn peninsula. The maximum energy of this age
in Wales was thus displayed along a belt immediately fronting the
Llanberis ridge; but at that boundary it came abruptly to a stop.

The several volcanic districts show nearly the same petrographical
types, following one another in the same order of decreasing basi-
city, but with significant points of difference. In the Wells
district of Radnorshire basalts were succeeded by hypersthene-
andesites, and these finally by rhyolites. About Arenig Fawr, in
Merioneth, the earliest term of this sequence is wanting. First
come agglomerates and tuffs of hypersthene-andesite composition,
then, after an interval, more acid andesitic material, followed by
dacitic and finally rhyolitic. In Snowdonia, not merely are basalts
lacking, but pyroxene-andesites are only feebly represented. The
great pile of lavas, with subordinate tuffs, is first dacitie and then
rhyolitic in composition, reaching also a higher degree of acidity
than is found elsewhere. The earlier types of. the sequence are
thus better represented in the south, and the later in the north.
In the Shropshire district, lying somewhat aside from the main
line of thrust, the volcanic record is much scantier, and is also
spread over a longer time. After the Stapeley andesitic ashes,
which seem to correspond with the lowest group of Arenig Fawr,
the Llandeilo strata here show no sign of contemporaneous vul-
canicity, and the completion of the sequence is represented in the
Bala Series by the Hagley and Whittery ashes, the admixture of
rhyolitic with andesitic material in the latter marking the final
phase.

The change from an alkaline to a calcic facies, which marked
the Llandeilo epoch, did not necessarily take effect simultaneously
in different areas. In the Cader Idris district the spilitic type
seems to have persisted while andesitic eruptions were breaking out

Ixxvlll PROCEEDINGS OF THE GEOLOGICAL society. [ vol. lxxiii,

elsewhere, for Dr. Cox has recognized as spilites the thick group of
lavas which forms the summit of the mountain, and with these
may probably be connected the intrusive sill of soda-granophyre
which makes so prominent a feature.

The intercalation in the voleanic sequence of sills which were
intruded almost contemporaneously is a noteworthy characteristic
of Ordovician vulcanicity, whether of alkaline or of ealcic facies.
It is illustrated by sills of ceratophyre at Abercastle and perhaps
of spilite on Mullion Island, but also by hypersthene-andesites in
the Arenig hills and Shropshire and by rhyolites fin the Lleyn
district. Again, some plug-like intrusions breaking through the
Cambrian of Caernarvonshire not improbably mark the sites of
Llandeilian voleanoes. With these exceptions the very numerous
intrusions in the Welsh area are later than all the volcanic
eruptions. Of a distinct plutonic phase of activity there is but
shght indication, and that only in the north-west, the diorite-
granite complex of Sarn being the chief representative.

The minor intrusions are found in all the districts, but on the
whole in greater force as we pass towards the north or north-west,
and this is especially evident in the case of the acid rocks. More-
over, in this direction—that of increasing stress—the concordant
habit gives place more and more to the transgressive. The intru-
sions, like the voleanic outbreaks, are sharply limited by the line
of the Llanberis ridge. The small Llanfaglen mass, if it belongs
to this age, is the only exception. The succession of different
types, in so far as it can be ascertained, is one of increasing
basicity. Some of the latest intrusions are proved in Shropshire to
invade the Pentamerus Limestone of the Llandovery Series. Else-
where the numerous intrusions of dolerite are intercalated in the
main voleanic group and at lower horizons, but they must certainly
be referred to a late date. While affecting the sill habit, they do
not make sills with any great lateral extension, but tend to occur
along anticlinal and synclinal axes. We may infer that they were
injected at a time when folding of the strata was already beginning,
namely: that folding which culminated towards the close of the
Silurian in the main Caledonian crust-movements.

Next to Wales the most important area of Ordovician igneous
activity is the English Lake District. Both here and in the
neighbouring inher of Edenside early eruptions are represented
by a few thin lavas and tuffs in the upper part of the Skiddaw
Slates. The rocks, which are much altered, have been described

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxix

as andesites, but their felspars can often be identified as oligoclase,
and one type in the Knock district is a characteristic spilite. The
much more important eruptions, which came later, lasted without
apparent interruption through Llandeilo time, and continued into
the Bala. The sequence, as set forth by my colleague, Dr. Marr,
is less simple than that seen in Wales. Pyroxene-andesite lavas
were followed by a much more widespread outpouring of basalts,
and then by activity of the explosive type, which produced a
great thickness of breccias and ashes. Many of these show a
commingling of basic and acid material. To this succeeded a
second group of pyroxene-andesites, and finally rhyolitic lavas
and breccias, which are in part interstratified in the Coniston
Limestone Group.

No distinct plutonic phase of this age is to be recognized in the
Lake District, but the intrusions which followed the volcanic out-
burst were numerous and of various petrographical types. The
largest masses, such as that of Ennerdale and Buttermere, are of
acid nature, sometimes with basic rocks involved in their marginal
parts. There is no conspicuous group of dolerite sills, but many
of the intrusions, ranging from acid to ultrabasic in composition,
have assumed an irregular sill-habit. The most basic occur in the
Skiddaw Slates and the most acid in the Coniston Limestone
Group, suggesting a vertical distribution in accordance with density.
The whole suite of rocks, volcanic and intrusive, excepting the
early sodic types, has a calcic facies. In this connexion the
frequent occurrence of red garnet is worthy of remark, and,
whether of primary or of metamorphic origin, its chemical signifi-
cance is the same. ‘The general geological relations are much less
clearly revealed than in Wales; but itis probable that here too we
are to recognize in the Llandeilian igneous action the influence of
a certain element of lateral thrust directed towards the north or
north-north-west. It is in that direction that the large acid
intrusions are situated. We can verify that at a later epoch, when
the rocks were folded, overthrust, and cleaved by a more intense
thrust on the same lines, these large igneous masses, perhaps
larger than their exposures indicate, acted in some measure as
a buttress. Whether their resistance was backed by an old ridge
concealed beneath the Skiddaw anticline, we do not know, but the
existence of such an ancient barrier would explain the absence of
intrusions on the farther side of that line.

It does not appear that the principal volcanic series of Wales and

Ixxx PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ vol. lxxin,

the Lake District is represented in the Southern Uplands of Scot-
land, although local: unconformity indicates some crust-movement
in that area at about the same time. Such vuleanicity as the
Llandeilo there shows seems to have been merely the continuation
of the Arenig outbreak. In Iveland early Ordovician eruptions
appear to have been confined to the marginal parts of the area. As
regards the interior, there are records of igneous rocks assigned to
the Llandeilo and Bala at numerous places from County Down to
the coast of Waterford; but our knowledge, both on the strati-
graphical side and on the petrographical, is still so imperfect that
general conclusions would have but little value.

During the Bala and part of Silurian time there was renewed -
subsidence, affecting more or less the whole of the area, but a
complete restoration of the early Ordovician conditions was not
now possible. Crustal stress, not wholly relieved by the Llan-
deilian vuleanicity, was doubtless unevenly distributed, and was
undergoing change. We find accordingly that igneous activity
during this time was feeble and sporadic, and showed no common
characteristics of the petrographical kind, though a reversion, or
partial reversion, to sodic types is often noticeable. Setting aside
such areas as the Shelve district and that of the English Lakes,
where Llandeilian vulcanicity was prolonged into Bala time, there
were revivals during the latter age at a number of isolated centres.
In the Southern Uplands there was an outbreak in the neigh-
bourhood of Peebles, the lavas being now of. acid instead of basic
nature, but still of sodic types. In the Berwyns again the alka-
line nature of the Bala igneous rocks is unmistakable ; but in some
other cases, such as the neighbouring Breidden Hills and the
_ Kildare inlier in Ireland, the petrographical facies is not clearly
characterized. These Bala revivals, if we except that of Peebles-
shire, were all in the interior of the area, but the scattered out-
breaks in the Silurian occurred in the marginal belt, those assigned
to the Upper Llandovery being in the neighbourhood of the Bristol
Channel. Of these the Mendip and Tortworth lavas, although
described as andesites, seem to be of somewhat alkaline composi-
tion, and the same may be true of the basic lavas with ‘ pillow-
structure’ at Milford Haven. The latest volcanic rocks of this
suite, seen at Clogher Head in the far west of Ireland, are mainly
of acid type.

The most highly alkaline of our Lower Paleozoic igneous
rocks, those of the Assynt district, I have perforce omitted. The

part 1] § ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxxi

stratiform habit of the plutonic complex, and of its component
parts, and the regular sill-form of its satellites assure us that the
intrusions were effected during a time of relative repose; but, as
regards their age,,we know only that they are younger than the
Durness limestones and older than the Caledonian overthrusting.
The lack of stricter chronological data and the isolated situation
of the district preclude any present discussion of the relations of

this interesting group.

Towards the close of Silurian time the original geosyncline had
been filled in, and indeed was being replaced by a geanticline.

‘The thrust, which had been renewed, now attained a much greater

intensity, until it culminated in the main Caledonian crust-
movements. The rocks yielded by folding, or cleavage, or over-
thrust, according to their lithological characters; but, allowing
for this, we see that the effects become more marked, both in
separate areas such as Wales and the Lake District and in the
region as a whole, when we pass northwards or north-westwards.
The climax is reached where the front of the great Highland
barrier itself has broken before the advancing earth-wave. Those
parts which had experienced to the full the effects of the Archean
metamorphism and had cores of Archzan plutonic rocks, could
yield only en bloe. The movement, therefore, instead of being dis-
tributed, was localized in great dislocations along what Mr. Barrow
styles the ‘ outer margin of crystallization.’ The displacement
at the Highland Border seems to be of the nature of an under-
thrust; a second master-fracture is represented by the line of
the Great Glen; and a third by the Moine overthrust, or by

the system of which it is the chief member. The south-

westward convergence of these three lines shows how the earth-
wave, travelling on the whole northwards, was swung round on
meeting an obstacle with a north-easterly and south-westerly
trend. The effect of these displacements was to sever the
Highland tract from the Lowlands, and to divide it into three
broad belts, South-Hastern, Central, and North-Western, each
narrowing somewhat in the south-westerly direction.

The Caledonian crust-movements were not immediately accom-
panied, like those of Archean age, by igneous action. The system
of intrusions known to Highland geologists as the ‘Newer Granites,’
with others of like age elsewhere in Britain, came somewhat
later, after crustal stresses had greatly relaxed. Accordingly,

VOL. LXXIEI. fe

Ixxxul PROCEEDINGS OF THE GEOLOGICAL soctrery. [ vol. lxxiil,

instead of fringing out into innumerable sheets and veins, they
have made large compact bodies. In general the intrusions have
avoided the neighbourhood of the great overthrusts, and are to
be found chiefly in the interior of those belts of country which
had behaved as tectonic units. Thus in the South-Eastern High-
lands a train of plutonic masses extends from Peterhead into
Argyllshire, and in the Central Highlands a somewhat less im-
portant train can be traced from the borders of Caithness to the
Ross of Mull. In each case the intrusions are largest and most
numerous towards the north-east, where the overthrusting had been
least, and the individual masses tend to have their long axes in
the common direction. All these facts go to show that, although
the great crust-movements were past, the intrusions were localized
and guided by a distribution of stress of the same general
character.

In Northern Ireland the plutonic masses of Slieve Gallion,
Pomeroy, and perhaps others, seem to carry on in a general way
the line of the Newer Granites of the Highlands. Farther south
a parallel belt of intrusion, referred with some confidence to this
age, is represented by the Galloway granites and those of Castle-
wellan, Newry, and Crossdoney in Ireland. Another belt, includ-
ing the English Lake District, the Isle of Man, and the long tract
of the Leinster granites, seems to mark the limit in this direction
of important Caledonian intrusions. In this bordering belt,
removed from the principal theatre of disturbance, the abrupt
boss-form tends to be replaced by a roughly stratiform habit, as is
clearly indicated by the underlying position of the Skiddaw,
Eskdale, and Foxdale granites. Even here, however, contem-
poraneous stress is proved by a certain horizontal differentiation,
seen in an increasing acidity and richness in white mica towards
the northern edge of each mass. The Leinster granite-tract is
more complex, and seems to be the result of several intrusions.
The granites of the main chain are foliated and sometimes
crushed in a manner which indicates stress during and after their
consolidation.

On the petrographical side there are some significant facts of
distribution. The name ‘ Newer Granites’ does not adequately
describe an assemblage of types which ranges from acid to ultra-
basic. In the Highlands, and especially in the large masses
situated towards the north-east, different rocks are often inti-
mately associated in a complex which may include _peridotites,

part 1] |§ ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxxill

diorites, quartz-diorites, and hornblende- and biotite-granites. In
this area, presumably near the principal focus of intrusion, the
more basic types are often well represented; but farther away, in
Galloway, the Lake District, and Leinster, they are either lacking
or of small importance. On the other hand, muscovite-bearing
granites, which are little in evidence in the Highlands, become
the dominant type in the most outlying belt. In Leinster we
find granites rich in microcline and muscovite. Here, too, south-
east of the main chain, and, as Prof. W. J. Sollas has shown,
of somewhat later intrusion, is a group of soda-granites, including
some rich in albite. Some of the minor intrusions presumably
related to the granites are of thoroughly alkaline composition, and
it is clearly suggested that we touch here the limit of the
distinctively calcic province which goes with the Caledonian dis-
turbance. |

The minor intrusions of the region in general, usually taking
the form of dykes, belong to simple petrographical types. There
are first porphyrites, perhaps not differing materially in composi-
tion from the average magma of the region, and then lamprophyres
with their complementary acid rocks. The distribution of stress
during a dyke-phase is necessarily more complex than during the
preceding plutonic phase. It is compounded of the regional
- system together with local stresses centreing in the plutonic intru-
sions, at least when these have the boss-habit. In the areas of
maximum disturbance the regional element is usually dominant,
but in outlying districts the local stresses prevail. Thus the
Caledonian dykes in the South-Eastern Highlands tend to have
the strike-direction, and those in Galloway the direction of dip;
but round the Shap granite the dykes have a markedly radiate
arrangement. é

A great system of crust-movement is not completed at one
defined epoch. It appears indeed that some part of the Cale-
donian overthrusting in the Highlands was effected during Old
Red Sandstone times: but, what is most in evidence during this
waning phase is not the lateral displacement, so much as the
differential vertical movement which went with it. Broad folds
were gradually formed, in the troughs of which the Old Red
Sandstone was deposited. ‘The conditions during this period, and
especially the manner in which the vulcanicity was related to
the broad geographical features, have been so well described by
Sir Archibald Geikie that a brief summary will suffice here. The

f2

Ixxxiv PROCEEDINGS OF THE GEOLOGICAL socteTy. [vol. lxxi,

principal trough was what is often called the Midland Valley of
Scotland, that is, the lowland tract, some 50 miles broad, which
divides the Highlands from the Southern Uplands. Subsidence of
this area, with correlative elevation of the contiguous tracts, con-
tinued through Old Red Sandstone times, and eventually passed
into important trough-faulting. It was along the two opposite
borders of the depressed area, where differential stress reached its
maximum, that voleanic eruption broke out. It began, as
Dr. Campbell has proved at Stonehaven, in the Downtonian, but

belongs in the main to the Lower Old Red Sandstone. On the -

north-western side, where activity was most vigorous, it affected
a stretch of country which, including its prolongation into Ireland,
has a length of about 300 miles. Of the other detached or semi-
detached areas of depression the most important are the Lorne and
Glencoe district on one side and the Cheviot district on the other:
In the far north two or more minor volcanic centres are indicated
in the Orkneys and Shetlands, while smaller outbreaks in the Kil-
larney district and in County Waterford mark perhaps the —
of voleanic action towards the west and south.

In these subsidiary basins the linear trough-form was much less
pronounced, and a marginal arrangement of voleanie vents is not
clearly discernible. None the less, the intimate relation between
igneous action and crustal displacement is very apparent. It is
illustrated in the most striking fashion by the cauldron-subsidence
of Glencoe with its accompanying outflow of lavas, as described by
Dr. Clough, Mr. Maute, & Mr. Bailey, ‘The plutonic phase which
succeeded, not in the Midland Valley but in Lorne, Cheviot, and
the Shetlands, tells the same story. In each area the plutonic
rocks have broken through as abrupt bosses in the midst of the
voleanic outpourings ; and the cylindrical plugs of Beinn Cruachan
and Beinn Nevis, associated with a peculiar piston-lke faulting,
are the analogues in this phase of the neighbourmg Glencoe
subsidence. The numerous dykes clustered round these two centres
present a sheaf-like arrangement about a north-easterly and south-
westerly axis, showing the regional stress modified in some degree
by the local. In each case there is a second, inner plug of
granite, younger than the majority of the dykes, implying a
duplication or alternation of the plutonic phase and that of minor
intrusions. In the Cheviot district stress of the regional type was
of little moment during the final phase, for the dykes about that
centre approximate to a regular radiate disposition.

ee

br 2

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxxv

The voleanie rocks of the Lower Old Red Sandstone belong
everywhere to the andesitic series, ranging from basalts to rhyolites,
but with pyroxene-andesites as the dominant types. No general
law of sequence is apparent. The plutonic rocks are mostly
granites and quartz-diorites, tending, however, in Argyllshire to
“monzonitic types. The dyke-rocks are comparable with those
found as satellites of the Newer Granites, and the petrographical
characters of the suite as a whole show that the influence of the
Caledonian disturbance was still felt. It is to be regretted that
we possess no detailed petrographical knowledge concerning the
feeble and sporadic revival of vulcanicity in Upper Old Red Sand-
stone time, when this influence was presumably exhausted. The
record of this episode is preserved in Caithness and the Orkneys,
in Arran, and in the neighbourhood of Limerick, and the rocks of
the first-named district are, according to Dr. Flett, basalts of
alkaline affinities.

Setting aside these scattered outbreaks, the next important
manifestation of igneous activity in Northern Britain began early
in Carboniferous time. The conditions were now wholly changed.

_ All folding related to lateral thrust had long ceased, and a general
subsidence was in progress. The change was reflected in the com-
position of the igneous magmas now brought into action, which
were of an alkaline character, at first but moderately pronounced
though becoming progressively stronger.

The subsidence was not uniform, and the vulcanicity related to
it had a distribution sufficiently significant. The chief theatre of
activity was the Midland Valley of Scotland, prolonged to what is
now the Mull of Kintyre; and the Carboniferous lavas and tufts
are thus found in close proximity to the very different volcanic
rocks of Old Red Sandstone age along the borders of the same
tract. Another volcanic belt was situated on the other side of the
Southern Uplands, corresponding roughly with the axis of the
Old Red Sandstone basin of Cheviot. There were also more iso-
lated centres of activity, one as far away as Limerick ; but I shall
deal with the matter briefly, taking the Midland Valley as a typical
area.

One point of interest brought out by the detailed mapping is
the gradual shifting’ of the theatre of activity, in general from east
to west. In the east volcanic rocks are practically confined to the
Calciferous Sandstone Series, and later igneous action took the form

Ixxxvl PROCEEDINGS OF THE GEOLOGICAL society. [ vol. xxii,

of intrusion; but in West Lothian, West Fife, and Stirlingshire
important volcanic groups appear in the Carboniferous Limestone
Series, and farther west vulcanicity continued in some districts into
the Upper Carboniferous. In the course of the revised survey of
the ground Dr. Flett, Mr. Barrow, and Mr. Bailey have added
much to our knowledge on the petrographical side. The voleanic
rocks are mostly of basic composition. Not every type of basalt
bears the evident mark of richness in soda, but their constant
association with mugearites and trachytes is always significant.
Intercalated among the lavas, with corresponding tuffs and agglo-
merates, the same types occur in the form of sills, which must
have been intruded during the voleanic period. Sills and dykes of
later intrusion belong to other petrographical types with more
strongly marked alkaline characters. They include phonolites,
analcime-dolerites, essexites, teschenites, and picrites, and in smaller
occurrences analcime-basalts, monchiquites, and limburgites.

In the eastern districts these alkaline rocks were apparently
intruded in Carboniferous Limestone times. Similar intrusions in
the west may be in part of like age, but some in Ayrshire are
found in strata as high in the succession as the latest Carboni-
ferous, if not higher. Further, these Ayrshire intrusions, or some
of them, are younger than, and evidently related to, the volcanic
group of the Mauchline basin, interstratified among red sandstones
which were assigned by Sir Archibald Geikie to the Permian.
Whether of Permian or of uppermost Carboniferous age, this
interesting volcanic outbreak is to be regarded as a pendent to the
Carboniferous igneous activity of the area. As described by
Mr. G. W. Tyrrell, the Mauchline lavas are all of very basie com-
position, and include olivine-basalts, sometimes approximating to
limburgite, analcime-basalts and monchiquites, and fresh nepheline-
basalts. The intrusive rocks, besides essexites, teschenites, and
picrites, comprise a number of peculiar types very rich in nepheline
or in primary analecime. The group as a whole marks the final
stage of the increasing alkalinity of the Carboniferous suite.

Of the Thornhill voleanic rocks, in Dumfries-shire, which Sir
Archibald Geikie correlates with the Mauchline group, we have as
yet no petrographical account; but in the numerous small volcanic
necks, with associated dykes and plugs, on the coast of Fife, also
assigned to the Permian, there are monchiquites and nepheline-
basalts closely comparable with those of Ayrshire. It is not
improbable too that at this late Palwozoic epoch diffused igneous

part 1 | ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxxvil

activity attained a wide extension through the Highlands. Scattered
dykes of the same distinctive types as those of the Ayrshire dis-
trict are found on the isles and littoral of Argyllshire, in the
Glenelg district, Central Ross, Hastern Sutherland, and the Orkneys,
and volcanic necks on the north-eastern coast of Caithness repro-
duce all the characteristics of those of East Fife.

Of more doubtful significance are the east-and-west dykes of
quartz-dolerite and tholeiite, which are scattered over the southern
half of Scotland and across the Border. They were intruded in
relation with the faulting of the country at or near the end of the
Carboniferous Period. Closely connected with them in the Midland
Valley of Scotland are numerous large sills of quartz-dolerite,
sometimes accompanied by granophyre; and to the same group we
may assign, not only the Whin Sill of Teesdale, but probably the
Tremadoe sills and perhaps the intrusions of Carrock Fell.! Quartz-
dolerite, though not itself an alkaline rock, has been claimed by
Mr. Dewey & Dr. Flett for the ‘spilitic series,’ and may possibly
sustain a complementary relation towards the types rich in soda ;
but more light on the question is needed before we can assign to
this group of intrusions its part in the Carboniferous system of
igneous activity.

If now we glance back at the history of our area during Paleo-
zoic times, it appears, from the point of view that I have tried to
suggest, as one complete cycle of events. The culminating episode
is that of the principal Caledonian crust-movements, to which the
preceding events led up, while the succeeding can be regarded as
their natural sequelew. That epoch marks the logical dividing-
point between Lower Paleozoic and Upper Paleozoic time.
Igneous action was an essential factor at numerous stages of the
cycle, but it assumed different phases and contrasted characters in
accordance with the changing stress-conditions. In particular,
we observe how, during the tranquil subsidence with which the
cycle began and ended, the magmas extruded and intruded were
invariably of alkaline nature, but calcic magmas took their place
at all times of special stress. Besides the great system of plutonic
intrusions which followed the main disturbance, the Paleozoic cycle
included three minor igneous cycles, the Ordovician, the Lower Old

1 The quartz-dolerites of Haweswater and other parts of the Lake District
are older than the Caledonian crust-movementsa.

Ixxxvill PROCEEDINGS OF THE GEOLOGICAL socrery. [vol. lxxiil,

Red Sandstone, and the Carboniferous. Of these the second was
ealcie and the third alkaline, while the first, as a result of the
premonitory disturbance in mid-Ordovician time, partook of both
characters in turn.

Other points of difference may be noted. The Lower Old Red
Sandstone cycle, which was most closely bound up with the opera-
tion of lateral thrust, illustrates a well-defined type of igneous
action. All manifestations were localized within certain areas,
having a definite relation to contemporaneous folding. Explosive
outbursts and the extravasation of lavas constituted the first phase
of activity; then came the intrusion of plutonic rocks in the form
of bosses ; and finally, if we disregard exceptional overlapping, the
injection of large numbers of dykes and sheets. In the voleanic
phase lavas of different kinds were poured out from neighbouring
centres. The plutonic rocks broke through in the midst of the
several volcanic districts, and sometimes in places already marked
out in the voleanic phase. The minor inclusions clustered about
the plutonic centres, and tended to orient themselves with reference
to those centres. In the earlier and later igneous cycles this
orderly disposition is not seen: there were no fixed foci of activity,
the theatre of operations shifting from one district to another.
The plutonic phase was scarcely represented in the Ordovician and
wanting in the Carboniferous Period. With this there went a
certain confusion between the extrusive and the intrusive phases,
shown by the frequent interpolation of quasi-contemporaneous sill-
intrusions in the volcanic succession.

In most of the history that I have briefly outlined Southern
England bore no part. Lying outside the region principally
affected by the Caledonian disturbance, this area presents so far a
much less eventful record. After the early Ordovician activity
had passed away from the border belt, there followed here a long
season of quiescence ; and, when vulcanicity again broke out, its
petrographical facies was unchanged. The Upper Devonian lavas
of North Cornwall and South Devon are spilites, together with
some soda-rhyolites in the Dartmoor district, and the associated
intrusions are mostly of albitized dolerites, with more basic types,
minverites and peridotites. Further, when another revival of
activity took place in the time of the Lower Culm, alkaline types,
including spilites, recurred once more.

It is interesting to remark that, during the earlier half of the

ham

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. ]xxxix

Carboniferous, two petrographical provinces existed in Britain,
both of alkaline facies but with different histories. The southern
one was an old-established province, and preserved the spilitic
character which seems to be associated with prolonged gentle sub-
sidence. ‘The northern province was a new one, representing a
reaction from the Caledonian ecalcic régime, to : which it was
genetically complementary. With this character there goes natur-
ally a wider diversity of petrographical types, showing progressive
enrichment in soda. The Irish districts of Philipstown and
Limerick are clearly related to Scotland, and the same is true of
the seanty development in the Isle of Man. The lavas of Derby-
shire and of North Somerset, as described by Mr. H. C. Sargent
and Prof. S. H. Reynolds respectively, present transitional cha-
racters. The occurrence of basalts and of certain types rich in
potash would attach these two districts to the northern province ;
but the Derbyshire rocks seem also to have certain affinities with
the Cornish, and those of Somerset include typical spilites.

In Northern Britain igneous activity lingered, as we have seen,
into the Permian. In the south it died out earlier, and here the
relative repose of the country was at length broken by the advance
of the Hercynian or Armorican crust-movements. Although these
were felt in some degree over a larger area of Britain, the extreme
effects—violent folding, cleavage, and overthrusting—are confined
to the south. Of the Caledonian zone of folding the full width
had been comprised within the limits of Britain, but it was only
the front of the Hercynian earth-wave that invaded our area. The
record of igneous activity related to this system is correspondingly
scanty. It includes first and foremost the intrusion of the granites
of Cornwall and Devon, which are found along a belt running from
Scilly to Dartmoor, with possible further extension in both direc-
tions.

The great Caledonian intrusions of the Highlands had followed
the principal movements after a decided interval, though not late
enough to escape all effects of crushing. In the case of our
Hercynian granites the interval seems to have been longer. The
cleavage and overthrusting of the older strata were long past, and
the disturbance had subsided into folding of a gentler type. It is
well known that posthumous folding on the same roughly east-and-
west axes affected Mesozoic strata at a much later epoch; and it
is probably by no mere coincidence that the Land’s End and Carn

XC -- PROCEEDINGS OF THE GEOLOGICAL sociery. [ vol. Lxxiii,

Menelez granites are situated on the prolongation of the axis of
Bray, the Dartmoor granite on the Purbeck axis, and the Lundy -
granite on the axis of North Devon. Under such mechanical con-
ditions intrusion did not assume the most boldly transgressive
habit. The form of any individual mass, in so far as it is revealed, .
presents a gently domed upper surface, though with steeply sloping
sides. ; .

The main Hercynian zone of plutonic intrusion, extending from
Britanny eastwards into Central Europe, presents a wide diversity
of calcic rock-types, ranging, for example, in the Harz district
itself from peridotite to. granite; but only the latest and most acid
differentiate from the primitive magma penetrated into the northern
fringe of the region, and is represented by the Cornish granites, rich
in alkali-felspars, and containing abundant light as well as dark
mica. The gaseous constituents, in which this granitic magma was
peculiarly rich, were eventually driven farther still, and seem to
have permeated the country over a wide extent. To pneumatolytic
operations connected with this invasion we owe the mineral wealth,
not only of Cornwall, but probably, as Dr. A. M. Finlayson has
maintained, of other mining districts much farther north.

The observed pneumatolytic effects in Cornwall were not imme-
diately connected with the intrusion of the granite, but belonged
rather to the succeeding dyke-phase. As is well known, the fissures
occupied by the principal lodes follow the general direction of the
strike, while.the ‘ cross-courses’ intersect them at right angles, and
often shift them. The two sets of fractures and displacement
clearly represent successive stages in the relief of crustal stress and
the establishment of equilibrium. Of the two complementary
groups of dykes the quartz-porphyries, often theimselves modified
by pneumatolysis, have the same roughly east-and-west bearing as
the principal lodes, while the lamprophyres tend to run north and
south like the ‘ cross-courses.’

Owing to the incompleteness of the Hercynian record in Britain,
the next manifestation of igneous action, coming after a long hiatus,
appears as an isolated episode. The evidence of it is seen in the
lower part of the New Red Sandstone succession, which rests with
discordance upon the folded Devonian and Carboniferous strata.
Whether Permian or Triassic, a question not yet finally resolved,
these younger strata belong to a time when folding had wholly
ceased, and a new movement had set in, which was of the nature of
a local subsidence. As seen in the Exeter district, the volcanic.

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. xCl

rocks include feeble flows of lava at several horizons, together with
thick bedded breccias composed in part of lke materials. The
lavas are of various types, and seem to have followed one another
in order of decreasing basicity. There are olivine-basalts containing
orthoclase, rocks intermediate between these and olivine-trachytes,
and again trachytes without olivine but rich in biotite and approxi-
mating to the minette and cuselite types. ‘The series may be
carried farther if we include the rocks of Cawsand and Withnoe, |
near Plymouth Sound: the one a biotite-trachyte and the other,
which has intrusive relations, a quartz-porphyry in which the
felspar is almost wholly orthoclase. Here then is a well-marked
series of rocks of strongly alkaline nature, rich not in soda but in
potash. Sir Jethro Teall has compared them with some of the
Permian lavas of the Continent, but in British petrography they
are unique. The origin of highly potassic rocks in general is a
problem upon which more light is needed, but it could not be
profitably discussed in connexion with this isolated occurrence.

Throughout the European area the time during which the Meso-
zoic strata were laid down, though marked by many vicissitudes,
was not interrupted by any crustal disturbance of an accentuated
type. At a later epoch all Southern Europe was involved in the
Alpine crust-movements, with attendant consequences which are
not yet exhausted. Some outlying ripples of this system reached
the British area, but there was no igneous outbreak in this country
which can be probably related to those events. Tertiary igneous
action in Britain has a different significance, and its seat was notin
the south but in the north and north-west. Affecting an area of
which the northern half of Britain is but a small fraction, this
immense and widespread activity was not connected with any
lateral creep of the earth’s crust, nor did it coincide with mere slow
subsidence within the limits of geosynclinal troughs. Its relations
seem to be with movements of a larger order. If we follow
Marcel Bertrand, we may connect this extra-Alpine Tertiary igneous
activity with the foundering of extensive tracts in the Atlantic
region, a deepening of an oceanic basin which was itself of no great
geological antiquity. I+ is clear at least that the important move-
ments in this region were differential movements in the vertical
sense, expressed by normal faulting instead of folding, and there-
fore in their tectonic effects plateau-building rather than mountain-

building.

xcll PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ vol. lxxiu,

The igneous manifestations were closely connected with these
vertical displacements, and the manner in which the uprise of
molten magma seems to be correlated with the sinking of faulted
blocks of country suggests that hydrostatic equilibrium was an
important factor in the process. In the British area the maximum
activity was developed within a sunken tract lying between the
ancient rocks of the Long Island on the one hand and the main-
land of Scotland on the other. Such a trough, however, is in no
wise comparable with that, for instance, of the Midland Valley of
Scotland in Carboniferous times, for it does not bear any ascertain-
able relation to the geological structure of the country which it
traverses. It is an ‘Atlantic,’ as contrasted with a ‘ Pacific’ feature.
Moreover, in respect of the more important events in the igneous
record, this area was merely part of a vast region affected by the
same activity.

These events characterized by a regional extension may be
summarized as: first, the outpouring of enormous quantities of lava ;
second, the intrusion of innumerable sills ; and, third, the injection
of a great system of dykes. The lavas, which can be assigned to
an Kocene age, did not emanate from great central volcanoes, but,
as Sir Archibald Geikie has shown, welled up through innumerable
fissures. The individual flows were not large, but collectively they
covered a very extensive region. Indeed, for any evidence to the
contrary, a continuous lava-field may have stretched from Antrim
to beyond Franz Josef Land, a distance of 2,000 miles. ‘The
free opening of so many fissures may be taken as proof that
there was at this time no crustal stress involving the element of
lateral pressure. The same conclusion may be drawn from the
behaviour of the sills which followed, remarkable for their regu-
larity and often of wide extent. Vertical movement was doubtless
renewed from time to time, for both lavas and sills are intersected
by considerable faults. Lava-flows and sills were fed by dykes,
but in addition there is a great profusion of dykes of later age.
Distributed over a large part of Britain, they maintain a common
direction, which seldom deviates far from north-west and south-
east, and show a total disregard for the structure of the country
which they traverse. Clearly, their intrusion was controlled by
some larger law.

Petrographically these extrusions and intrusions are characterized
by an overwhelming preponderance of basic types, with an alkaline
tendency which is sometimes rather latent than expressed, but

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. xclll

sometimes strongly marked. These Tertiary rocks as a whole have
much in common with the Lower Carboniferous igneous rocks of
the Midland Valley. Various types of Carboniferous basalts and
dolerites are closely reproduced, in addition to the very significant
mugearites. Trachytes are less prominent, but are found in Skye,
Ardnamurchan, and perhaps elsewhere. In considering the widely
distributed amygdaloidal basalts, it is to be remembered that the
contents of the vesicles are an integral part of the rock. It is, then,
of interest to observe that the Tertiary and Carboniferous lavas are
the chief source in Britain of zeolites, while the very different lavas
of the Old Red Sandstone are the home of agates and onyxes. In
not a few of the Tertiary rocks primary zeolites, chiefly but not
exclusively analcime, make part of the general fabric, and this is
true of lavas, sills, and dykes. Another index of an alkaline com-
position is the incoming of a pleochroic titaniferous augite.

In addition to the Tertiary crust-movements already noticed, of
simple type and having a vast extension, there were within the same
region disturbances of a different order, strongly accentuated and
strictly localized about distinct centres. With these is closely
related another series of igneous rocks, chiefly in the form of
plutonic masses with a host of minor intrusions as satellites. The
principal centres are in the tract, already mentioned, which embraces
the Inner Hebrides and the Clyde Isles, and the most remarkable of
all is the Mull centre, situated in the middle of that tract. The
relations here recall those at the Old Red Sandstone centres of the
West Highlands, but show a much higher degree of complexity.
They have been unravelled by the labours of the Geological Survey,
and the map of the district, with the accompanying memoir, will
doubtless add largely to our knowledge of the mechanism of igneous
intrusion. Pending the publication of that work, I will pass over
the subject with a few words.

The special centres were already marked out in the voleanic
phase, or even earlier. In Mull there was a cauldron-subsidence,
accompanied by outpourings of ‘ pillow-lavas” and later a girdle of
voleanic vents. The great voleanic vent of Kilchrist in Skye and
that of Central Arran also belong to an early date, and may have

-something of the same significance. At subsequent epochs the
vertical movement at the special centres, though not always in the
same sense, seems to have been in general one of elevation. Where
the local movements were strongly emphasized, the plutonic in-
trusions are sharply transgressive, and they stand in evident relation

xclv PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ vol. lxxiii,

to special tectonic features such as ring-like faults and folds. At
centres where the disturbance was of a less violent kind there is a
tendency to a laccolitic or roughly stratiform habit. Of the minor
intrusions the most remarkable are the groups of inclined sheets,
dipping inward at angles up to 45°. Such sheets are very numerous
in the Cuillin Hills of Skye, and are represented in less force about
the centres of Rum and Ardnamurchan. In Mull they occur in
extraordinary numbers, and are disposed about two neighbouring
points. About some of the plutonic centres there are local groups
of dykes with a radiate arrangement; or, again, the dykes of
the regional series become unusually numerous, and are drawn
into a sheaf-like disposition. In all these phenomena we see the
evidence of a special distribution of stress related to the prescribed
centres.

Petrographically the local groups of rocks show more variety
than the regional series. Apart from some complications in the
Mull district, the sequence, when complete, ranges from ultrabasic
to acid in the plutonic phase, and the reverse in the phase of minor
intrusions. The parent stock of all must have been the same basic
magma as that which provided the plateau-basalts of the region and
other rocks with evident alkaline affinities. None the less we find
that, about the centres of acute disturbance in the interior of the
tract, the local groups of rocks belong to distinctively calcie types :
peridotite and allivalite, eucrite, gabbro and norite, augite- and
hornblende-granite, and biotite-granite.| Towards the limits of
the tract, where the locally developed stresses were much less
intense, the alkaline facies reasserts itself in the plutonic rocks.
This is shown in the north by the massive sheets of riebeckite-
granite on Raasay, while in the south it is suggested by the Arran
granites, rich in microperthite, and still more clearly by the
paisanite of Ailsa Craig. .

The same law is illustrated by the rocks of regional distribution
themselves, where they come within the influence of the special
centres of stress. The basaltic lavas of Central Skye seem to be
decidedly of less alkaline composition than those in the northern
part of the island. A like conclusion emerges when we compare
the dolerite sills in the interior of the specified tract with those of

1 An anomaly, from this point of view, is the occurrence of an alkali-syenite
forming a reef opposite Carsaig, on the south side of Mull,

part 1] ANNIVERSARY ADDRESS OF THE PRESIDENT. XCV

Raasay and the Shiant Isles in the north, or again with the
analcime-dolerite (crinanite) sills of Southern Arran and the ortho-
phyre with riebeckite and egirine on Holy Isle. If we try to push
the examination farther afield, where the only Tertiary rocks pre-
served are in the form of dykes, we find very few trustworthy
data. A number of dykes in Argyllshire and elsewhere, belonging
to very characteristic alkaline types, have sometimes been claimed
as Tertiary, but I have assigned them, upon a balance of evidence,
to a Permian age. When, however, we pass beyond the bounds of
Scotland, southwards and westwards, we meet with a few scattered
occurrences which have a special interest. The nepheline-basanite
of Butterton, the phonolite of the Wolf Rock, and the peculiar
eegirine-bearing type of Rockall are reasonably regarded as
Tertiary. They are of much more strongly alkaline composition
than the known rocks of this age in Northern Britain, and find
their nearest relatives in the Cape Verd Isles and other island
groups far to the south. If then we are to distinguish among
the ‘younger’ igneous‘rocks of this part of the world a strongly
alkaline North Atlantic region, connected with the collapse of con-
siderable tracts in mid-ocean, and a less strongly alkaline Arctic
region, including the Brito-Icelandic Province of Judd, we can
point to one more important dividing line crossing the British
area. It is in the nature of the case, however, that much of the
evidence by which we might follow out this suggestion is buried
beneath the waves.

Here I must bring my rough summary of igneous action in
Britain to a close. Apart from personal shortcomings, it has
suffered from necessary condensation and sometimes from the
insular method of treatment imposed by considerations of time and
space. I have tried to show that at different periods of its history
our area has been differently mapped out into petrographical
provinces, and this in a manner quite definitely related to the larger
displacements of the earth’s crust. The inference seems just that
the distribution of crustal stress is a dominant factor
in determining the petrographical facies of igneous
rocks. One way in which this factor may operate has been
suggested, and I venture to think that in any theoretical discussion
of the question a place must be found for that intercrustal creep
of alkaline magmas which I have specially emphasized. That it is

li a

X¢CVi PROCEEDINGS OF THE GEOLOGICAL socretyY. | vol. Ixxiii,

the only selective action determining the geographical distribution
of different classes of igneous rocks is not claimed. In particular,
any discussion of that question as a whole must try to assess the
importance of isostasy, and the consequent tendency of the denser
basic magmas to accumulate beneath the ocean-basins. This and
some other elements of the larger problem may be eliminated in
considering so small an area as the British Isles; which neverthe-
less can still produce, as I have shown, not a few unsolved questions
to engage the attention of petrologists in the future.

parj1] § PROCEEDINGS OF THE GEOLOGICAL SOCIETY. xevil
- 2

February 28th, 1917.

Dr. ALFRED Harker, F.R.S., President,
in the Chair.

Roger Howel, Bryncoch, Neath (Glamorgan) ; George Catterall
Leach, Inspector of Mines, Sitarampur, E.I.R., Bengal (India) ;
Ashley Gordon Lowndes, B.A., The Grange, King’s School,
Canterbury ; and Ernest Neaverson, B.Sc., 16 Mandeville Road,
Aylesbury, were elected Fellows of the Society.

The List of Donations to the Library was read.

The following communication was read :—

‘Fourth Note on the Piltdown Gravel, with Evidence of a
Second Skull of Hoanthropus dawsoni. By Arthur Smith
Woodward, LL.D., F.R.S., V.P.G.8. With an Appendix on the
Form of the Frontal Pole of an Endocranial Cast of Hoanthropus
dawsont. By Prof. Grafton Elliot Smith, M.A., M.D., F.R.S.

Two fragments of skull and a tooth of Hoanthropus dawsoni,
together with a supposed hammer-stone from the Piltdown gravel,
were exhibited by Dr. A. Smith Woodward, F.R.S., V.P.G.S., in
illustration of his paper.

Restored models of the Piltdown skull made by the British
Museum and the American Museum of Natural History, and plaster
casts of the original fragments on which these reconstructions
were based were also exhibited by Dr. A. Smith Woodward.

A restored model of the Piltdown skull, made by the Royal
College of Surgeons, was exhibited by Prof. Arthur Keith, F.R.S.

A plaster cast of a fossil human skull from Talgai (Queensland)
was exhibited by Prof. G. Elliot Smith, M.A., M.D., F.R.S.

A mandibular ramus of a Chimpanzee, showing molar teeth
worn flat, was exhibited by Mr. W. P. Pycraft, A.L.S.

March 14th, 1917.

Dr. A. SmuirH Woopwarp, F.R.S., Vice-President,
in the Chair.

George Fairbairn, M.C., Assistant Commandant of Mines, R.E.,
18 Welbeck Court, London, W.; and Major William Gregson,
B.Sc., Blaina (Monmouthshire), were elected Fellows of the
Society.

The List of Donations to the Library was read.
VOL. LXXIII. g

XCVlll PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ vol. lxxiii,

The following communication was read :—

‘The Carboniferous Limestone bordering the Leicestershire
Coalfield.’ By Leonard Miles Parsons, D.I.C., B.Sc., F.G.S.

Specimens and microscopic slides of dolomite, and fossils from
the Carboniferous rocks of the Leicestershire Coalfield, were exhi-
bited by L. M. Parsons, D.I.C., B.Sc., F.G.S., in illustration of his

aper.
; The following maps were also exhibited :—Geological Survey of
Scotland: l-inch Map, Sheets 36—Kilmartin, and 60—Rhum,
1917, presented by the Director of H.M. Geological Survey. -

March 28th, 1917.

Dr. ALFRED Harker, F.R.S., President,
in the Chair.

Guthrie Allsebrook, Moorland, Shinfield, near Reading; Thomas
Wilham Brown, B.Se., A.M.S.E., 54 Brookvale Street, Belfast ;
and Scoresby Routledge, M.A., 9 Cadogan Mansions, Sloane Square,
S.W.1, were elected Fellows of the Society.

The List of Donations to the Library was read.

The PreEsIDENT announced that the Council had awarded the
Proceeds of the Daniel-Pidgeon Fund for the present year to
Artuur Hoimes, D.I.C., B.Sc., F.G.S., who proposes to conduct
researches in connexion with the Geology of the Dartmoor Border,
around Okehampton and Belstone.

The following communication was read :—

‘The Carboniferous Limestone Series on the South-Eastern
Margin of the South Wales Coalfield... By Frank Dixey, M.Sc.,
F.G.S., and Thomas Franklin Sibly, D.Sc., F.G.S., University
College of South Wales & Monmouthshire, Cardiff.

Lantern-slides, rock-specimens and microscope-slides of rocks from
the Carboniferous Limestone Series on the South-Eastern Margin
of the South Wales Coalfield were exhibited by F. Dixey, M.Se.,
F.G.S., and T. Franklin Sibly, D.Sc., F.G.S., in illustration of
their paper.

The following map was also exhibited :—Geological Survey of
England & Wales—l-inch Map of Sheffield (Barnsley), temporary
edition, 1917, presented by the Director of H.M. Geological Survey.

part 1] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. XC1Xx

April 18th, 1917.

Dr. ALFRED Harker, F.R.S., President,
in the Chair.

The List of Donations to the Library was read.

The following communication was read :—

‘The- Development and Morphology of the Ammonite Septum.’
By Prot. Henry Hurd Swinnerton, D.Sc., F.G.S., and Arthur
Elijah Trueman, M.Sc. ;,

Specimens used in the investigation of the relationship between
septal sections and stages in the sutural development of Ammonites,
as also the instrument designed for taking measurements, were
exhibited by Prof. H. H. meron D.Sce., F.G.S., and A. E.
Trueman, M.Sc., in illustration of their paper.

A serics of Ammonites, some in section, and others ground to
show the form of the edges of the septa, were exhibited by W. F.
Gwinnell, B.Se., F.G.S.

May 2nd, 1917.

Dr. Aurrep Harker, F.R.S., President,
in the Chair.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘Supplementary Notes on Aclisina De Koninck, and Acl?-
soides Donald, with Descriptions of New Species.’ By Jane
Longstaft (née Donald), F.L.8. (Communicated by Dr. G. B.
Longstaff, M.A., F.G.S.)

2. ‘The Microscopic Material of the Bunter Pebble-Beds of
Nottinghamshire and its Probable Source of Origin.’ By Thomas
Harris Burton, F.G.S.

Specimens of Aclisina and Aclisovdes were exhibited by
Mrs. Jane Longstaff, F.L.S., in illustration of her paper.

Lantern-slides and microscope-slides of pebbles and sands from
the Bunter Pebble-Beds of Nottinghamshire were exhibited by
ieeeoucton, F.G.S., in illustration of his paper.

There was also exhibited a geological map of Dublin, on the scale
of 6 inches to the mile, 1917. ~ presented by the Geological Survey
of Ireland.

c PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [{ vol. lxxin,

May 16th, 1917.

Dr. ALFRED Harker, F.R.S., President,
in the Chair.

The Rev. Joseph Fowler, M.A., Nidd Vicarage, Harrogate
(Yorkshire), was elected a Fellow of the Society.

The List of Donations to the Library was read.

A Lecture on British Geological Maps as a Record of
the Advance of Geology was delivered by THomMAs SHEPPARD,
M.Sce., F.G.8. He observed that geological changes were in many
cases indicated on old topographical maps; consequently, very old
plans and charts were of use in connexion with geological enquiries,
although not strictly geological in character. Some examples of
maps, dating from Elizabethan times, were exhibited, and they
showed that in the Humber area great changes had taken place :
in certain districts large tracts of land had been denuded, and many
towns and villages had disappeared; in others, large stretches of
reclaimed land marked places where water once stood. So long ago
as 1595 writers were familar with hthological differences in various
parts of the country, and in 1683 Martin Lister read to the Royal
Society a paper in which he definitely suggested ‘A Scheme for
the Mapping of Soils and Rocks,’ wherein he mentioned the various
kinds of rocks that occurred in Yorkshire; but his scheme was not
actually carried out until a century later. Strachey (1719) and
Packe (1748) produced some remarkable geological sections and
plans..

The first systematic series of maps, illustrating the geological
features of the counties, was issued in the Reports of the old
Board of Agriculture, and dated from 1793 to 1822. These
Reports usually contained ‘soil-maps’ of the counties described,
upon which chalk, sandstone, limestone, peat. marl, gravel, ete.
were shown by colours and shading. William Smith was certainly
familiar with these ‘Agricultural Surveys,’ and doubtless they
provided him with information that assisted him in the preparation
of his great map of the geology of England and Wales, issued in
1815.

One of the earliest and most serious attempts to prepare geoio-
gical maps was by Prof. Jameson, who read a paper in 1805 ‘On
Colouring Geognostical Maps’ (Wernerian Nat. Hist. Soe. vol. i,
published 1811); but the enormous number of complicated signs
and symbols that he suggested proved unsuitable for practical
purposes, although there were many good features in his colour-
scheme.

The first strictly geological map (now in the Society’s possession)
was apparently that made by William Smith in 1799, showing the
geological structure of the Bath District. This had been proved
by the Lecturer to have been coloured on a plan originally issued
in ‘The New Bath Guide’ of 1799. The first geological map of

part 1] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. cl

England and Wales was a small one, also by Smith, and it was
presented to the Society by ‘the Father of English Geology’ when
the first Wollaston Medal was awarded to him in 1831. The
Lecturer discussed the history of the various maps and sections pub-
lished by Smith, and described two hitherto unknown maps (of the
counties of Durham and Northumberland) by the same author, in
the Society’s possession. He also exhibited one of the Scarborough
district, found while he was cataloguing the Society’s maps; all
trace of this particular map had been lost for over eighty years.
Smith’s finest piece of work, his map of the Hackness district, dated
1832, apparently had not been seen by any worker since its pubh-
cation, and the Lecturer explained how he had recently been able to
trace two copies. One of them, which was exhibited, he presented
to the Society.

In the Society’s possession also is an extensive and valuable
collection of the maps of Greenough, both published and in
manuscript. Among an extraordinary series of coloured maps of
England and Wales, and of the British Isles, issued during the
middle of the 19th century, those of Arrowsmith, Murchison,
Walker, Ramsay, Ravenstein, Knipe, Phillips, and Johnston are
especially noteworthy.

The Society’s collection includes geological maps of Scotland and
Ireland, some of great value and historical interest. Of Scotland,
the remarkable series by MacCulloch, published and in manuscript,
shows that the collection is by far the finest as regards early maps
dealing with the geology of the country. A manuscript map of
Scotland by Necker is dated 1808 (earlier than Smith’s large map
of England and Wales), and is undoubtedly the oldest. Among
the maps of Ireland there is the fine series by Griffith, which
includes a few examples not known by Judd or other writers on
the subject.

As examples of privately published maps, those by Sanders of
the Bristol Coalfield, Jordan’s London District, and Elias Hall’s
Lancashire area were described. The Lecturer concluded by
referring to a Catalogue of geological maps (other than the Geolo-
gical Survey Publications) which he had in course of preparation.
This already contained details of approximately 3000 maps.

The PRESIDENT commented on the value of Mr. Sheppard’s work,
and on the important discoveries that he had made, and expressed
the thanks of the Fellows present for his lecture.

Lantern-slides and examples of important early geological maps
were exhibited in illustration of the lecture.

June 6th, 1917.

Dr. ALFRED Harker, F.R.S., President,
in the Chair.

The List of Donations to the Library was read.

cll PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ vol. Ixxii.

The following communications were read :—

1. ‘On the Geology of the Old Radnor District, with special
reference to an Algal Development in the Woolhope Limestone.’
By Edmund Johnston Garwood, Sc.D., F.R.S., F.G.S., and
Edith Goodyear, B.Sc.

2. ‘Jurassic Chronology: I. Lias.’ By S. 8. Buckman, F.G.S.

Lantern-slides and specimens of rocks from the Old Radnor
District were exhibited in illustration of the paper by Prof. E. J.
Garwood, Se.D., F.R.S., and Miss E. Goodyear, B.Sc.

Examples of Jurassic ammonites were exhibited by S. S.
Buckman, F.G.S., in illustration of his paper.

June 20th, 1917.

Dr. ALFRED Harker, F.R.S., President,
in the Chair.

John Cecil Mackmurdo Given, M.D., M.R.C.P., Lowood, Mossley
Hill, Liverpool; William Watts Ratcliff, A.M.Inst.C.E., R.E.,
The Willows, West Drayton (Middlesex), Staff Officer to the Chief
Engineer, XIIIth Army Corps; Ewart Watson Ravenshear, B.A.,
Captain, 7th Royal Berkshire Regiment; and Francis Whitworth
Wright, J.P., B.A., M.I.M.E., Lieut. R.F.C., 141 Church Street,
Chelsea, $.W. 3, were elected Fellows of the Society.

The List of Donations to the Library was read.

The following communications were read :—
to)

1. ‘The Pre-Cambrian and Associated Rocks of the District
of Mozambique.’ By Arthur Holmes, D.I.C., B.Sc., F.G.S.

2. ‘The Inferior Oolite and Contiguous Deposits of the Crew-
kerne District (Somerset). By Linsdall Richardson, F.R.S.E.,
F.G.S.

A manuscript map of the district of Mozambique, rock-specimens,
and thin sections of rocks were exhibited by Arthur Holines, D.1.C.,
B.Sc., F.G.S., in illustration of his paper.

The following were also exhibited :—Geological Map of the Wit-
watersrand Goldfield, in three sheets (scale= 1: 60,000; 1916)—
presented by the Geological Survey of the Union of South Africa ;
and Geological Survey Map of Japan, Sheets Niagata & Shiriya-
zaki, 1916, and Takayama, 1917 (scale=1 : 20,000)—presented by
the Imperial Geological Survey of Japan.

ie
oe thon 7s
; (~ 44 eg. fe
f on
PEON iis
THE \ %,

a]
QUARTERLY JOURNAL

OF

THE GEOLOGICAL SOCIETY OF LONDON.

Vino beXoxee ee
For 1917.

1. Fourtu Nove on the Prirrpown GRAVEL, with EVIDENCE of
a@ SECOND SKULL OF HoanTHROPUS DAwsoNnl. By ARTHUR
Smith Woopwarp, LL.D., F.R.S., V.P.G.S. With an Ap-
pendix by Prof. Grarron Exxior Smiru, M.A., M.D., F.R.S.
(Read February 28th, 1917.)

[Puate I.]

THE Piltdown gravel has already been well described by the late
Mr. Charles Dawson,! who pointed out its variable character and
concluded that its two lower layers at least could not be very dif-
ferent in age.? Further extensive excavations last summer round
the margin of the area previously explored, tended to confirm this
impression, and to show that the whole deposit is a shingle-bank
which may have accumulated within a comparatively short space
of time. The lenticular patches of the dark-brown ferruginous
gravel proved to be even more variable than before, and they were
seen to pass both into the sandy clay below and into the less clayey
deposit above. Large flints and waterworn pieces of Wealden sand-
stone were still observed scattered irregularly through the finer
material. The characteristic ‘subangular flints’ were also found
at intervals in the basal sandy clay. More interesting, however,
was the discovery in this layer of numerous large elongated flints
and pieces of Wealden sandstone, with their long axis more or less
nearly vertical. The evidence of flood-action thus became complete.

1 Q. J. G. S. vol. Ixx (1914) p. 82
2 Toid. vol. Ixxi (1915) p: 147.

Q. J.G:S. No. 289. b

2 DR. A. SMITH WOODWARD ON A [vol. Ixxin,

Fig. 1—Supposed hammer-stone of flint
from the Piltdown Gravel; half of
the natural size.

[A=side view; B=face showing the original crust
of the flint; C=extensively-flaked face: «=
battered portions. |

Although so much
material was carefully
examined, neither bones
nor teeth were met with.
The only noteworthy
find was a_ battered
nodule of black flint,
which occurred in a
rather sandy patch of
the dark-brown gravel
resting immediately on
the basal layer. This
specimen, which is con-
spicuously different from
the other flints and very
little stained, may have
been used by man as a
hammer-stone (text-fig.
1). It measures nearly
13 centimetres in length
by 9°5 cm. in width,
and about 7°5 cm. in
maximum _ thickness.
The largest face (C),
which is almost flat, has
been produced by coarse
flaking, and bears marks
of much battering round
the edge, especially at
one angle (#7). The op-
posite large face (B) is
covered for the greater
part by the original
crust of the flint-nodule,
but is strongly battered
along the two cross-
ridges (a) and one con-
necting edge, from which
lateral flakes have been
struck. Where not thus
flaked the periphery of
the flint is also covered
with the original crust.
Like the later undoubted
hammer-stones, there-
fore, this flint has been
used mainly on two
opposite faces; but it
appears to owe its pre-
sent form merely to use,

part 1] SECOND SKULL FROM THE PILTDOWN GRAVEL. 3

not to any original intentional shaping. All the edges are re-
markably sharp, and the black facets bear scarcely any patina.

The wide distribution of the Piltdown gravel, as determined by
its characteristic brown flints, was shown by Mr. Dawson in his
map of 1912.1 It could easily be traced in the ploughed fields of
the district ; but, notwithstanding the most careful and persistent
search, it yielded no fossils, except at the original locality, until the
winter of 1914-15./ One large field, about 2 miles from the Pilt-
down pit, had especially attracted Mr. Dawson’s attention, and he
and I examined it several times without success during the spring
and autumn of 1914. When, however, in the course of farming,
the stones had been raked off the ground and brought together into
heaps, Mr. Dawson was able to search the material more satisfac-
torily ; and early in 1915 he was so fortunate as to find here two
well-fossilized pieces of human skull and a molar tooth, which he
immediately recognized as belonging to at least one more individual
ot Koanthropus dawsoni., Shortly afterwards, in the same gravel,
a friend met with part of the lower molar of an indeterminable
species of rhinoceros, as highly mineralized as the specimens pre-
viously found at Piltdown itself.

The most important fragment of human skull is part of the supra-
orbital region of a right frontal bone adjacent to the middle line
(PL I, figs. 1 a—1d). It is in exactly the same mineralized condition
as the original skull of Hoanthropus, and deeply stained with iron-
oxide. It is also similarly thickened, exhibiting the characteristic
very fine diploe with comparatively thin outer and inner tables of
dense bone. It provides a portion that was absent in the first
specimen, its upper end approaching within a few millimetres the
level of the anterior broken edge of the left frontal in the latter,
while its lower portion now leaves only about 2 cm. of the supra-
orbital border unknown. Its gently upward and backward curva-
ture (figs. 1¢ & 1d) is that already assumed in restorations, and its
outer face is marked only by a small and low supraciliary ridge (s.),
which is well above the orbital border, fades away medially at the
beginning of the glabella, and only extends laterally just beyond
the supraorbital notch (7.). On the inner face of the bone (fig. 1 6)
the median border bears an unusually stout sagittal crest (¢.), which
is slightly marked by a groove for the longitudinal sinus. The im-
pressions of the convolutions of the frontal lobe of the brain are
feeble, but show some features of interest, as described by Prof.
Elliot Smith in the Appendix (p. 7). The orbital plate, as might
be expected, is broken away, and the rather tumid glabellar region
is imperfect below, exposing small air-sinuses, which do not appear
to extend along the supraorbital border beyond the supraorbital
noteh. This notch (figs. 1 a & 1 6, n.) is especially conspicuous (per-
haps enlarged by abrasion in the fossil), and the supraorbital border
to the right of it forms a comparatively sharp edge (figs. la, 1 3,
&1d). The median plane of fracture (fig. 1 ¢) follows closely the

1 Q.J.G.S. vol. lxix (1913) pi 118.
B2

+ DR. A. SMITH WOODWARD ON A » (vol: ain,
line of the interfrontal suture, which, however, judging from
the appearance of the broken sur face, cannot have been persistent.
It shows a complete septum (a.) between the air-sinuses of the
right and left sides, and indicates the total thickness of the bone
at the frontal crest.

The following are some measurements of thickness of the new
fossil, in millimetres :—

Supero-lateral angle.’ ...)3./.0...0.0i ws 10
Thinnest part of lateral.edgée 2.2...) 4h... 8
Sharp supraorbital border (fig. 1d) . (2... .-:. eee 12
Upper -end ‘of sagittal’ crest. «o>. b.:c3 56-000 13

Lower end of sagittal crest

With these may be compared the following measurements of
thickness of the original specimen of Hoanthropus :—

Left frontal at the nearest point of pape to the
part represented by the new fossil . _. S32 ee
Thinnest part of frontal above the left orbit ; 20 9

The second fragment of human skull is the middle part of an
occipital bone, w hich is also well fossilized, but seems to have been
weathered since it was derived from the gravel (Pl. I, figs. 2a@—-2c).
Though still stout, it is thinner than the corresponding bone of
Hoanthropus from Piltdown, and differs from the latter in at least
one important respect. The outer face of the fossil (fig. 2@) ex-
tends upwards just beyond the superior curved line (s.¢./.) which
passes along a gentle transverse prominence ; while the lower edge
of the fragment is a little below the inferior curved line (7.c./.).
The inner face (fig. 2 4) shows the internal occipital crest (7.0.c.),
with its protuberance, displaced somewhat to the right of the
median line, the fossa for the left cerebral hemisphere (cer.) being
relatively wide. The broad transverse grooves for the lateral sinus
(/.s7.), however, are at the same level on the ‘right and left sides,
and the upwardly turned groove at the toreular Herophili (¢.) of
the longitudinal sinus is large and conspicuous on the right. The
fosse for the cerebellum “(cb.) indicate very little asymmetry.
The brain must thus have been much more nearly symmetrical
than that of the original specimen of Hoanthropus—a difference
that is to be regarded as merely an individual variation. When,
however, a vertical section of the bone is made along the external
occipital crest (fig. 2a, e.0.c.) which marks the median plane
(fig. 2¢), an essential difference is observable between this and
the previously-described specimen. The superior curved line of
the outer face and (by inference) the inion, or external occipital
protuberance, are distinctly above the level of the upper edge of
the lateral sinus which denotes the limit of the tentorium covering
the cerebellum; whereas, in the first specimen, the same external

part 1] SECOND SKULL FROM THE PILTDOWN GRAVEL. 5)

and internal features are opposite, as in modern man. _ It is there-
fore clear that, in the skull represented by this new fossil, the
muscles of the neck must have extended farther up the occiput
than is usually the case. Such an upward extension of the neck-
muscles is already known in Neanderthal man, where it is supposed
to be correlated with the support of a heavy face; and it may be
that in still earlier man the condition was variable, perhaps even
different in the male and in the female. If this were so, there
would be no reason to hesitate in referring the fragment now
described to Hoanthropus dawsont.

The. following are some measurements of thickness of the new
occipital bone, compared with that of Hoanthropus previously
described :—

New fossil. Hoanthropus.
reahess HMICKMESS ::..,.... 0.00.0 00 00.0005 17 mm. 20 mm.
Thickness at internal proéuberance... 16 mm. 20 mm.
Thinnest part of cerebellar wall...... 4mm. 4mm.

The tooth, discovered by Mr. Dawson in the same locality as the
two pieces of bone, is a left first lower molar (Pl. I, figs. 4 a—4e)
agreeing very closely with that of the original specimen of Hoan-
thropus dawsoni, but more obliquely worn by mastication. It is
equally well fossilized, and stained brown with oxide of iron in the
usual manner. The difference in the mode of wear can be seen in
its anterior end-view (4¢) when this is compared with -that of the
original specimen (fig. 5). The tooth, as before, is elongated
antero-posteriorly, and its grinding surface (fig. 4a) lacks any
well-defined cruciform fissure, its central area being an irregular,
nearly smooth depression. Of its two inner cusps, the anterior is
the larger, and must have been more elevated than the posterior
cusp (its worn apex exposing a small triangular area of dentine,
while the latter is still covered with enamel). Both the outer cusps
are worn down to the dentine, the anterior exposing a slightly larger
area than the posterior cusp. The small fifth cusp behind 1s, as
usual, nearest the outer border, from which it is visible in side
view (fig. 40). It is also worn down so as to expose a very small
area of dentine. Between this, the postero-internal cusp, and the
posterior border of the tooth, the crown (fig. 4a) is slightly marked
by a. small transversely- extended depression. In outer view
(fig. 4:6) and inner view (fig. 4c), the depth of the crown is well
seen, and the two cusps are clearly separated by a fissure. At
both ends of the tooth (4d, 4.¢), a pressure-scar is distinguishable.
The two roots, of which, only the upper portions are preserved, are
separate nearly as far as the neck of the tooth, which is but
shghtly constricted.

If the new tooth be compared with the corresponding molars of
a Melanesian (figs. 6a—6¢), a Tasmanian (figs. 7 a-7d), and a
Chimpanzee (figs. 8 a—8 e), a approxunately the same size, it will
readily be recognized as essentially human. In the considerable

6 - DR. A. SMITH WOODWARD ONA —_—[ vol. Ixxin,

depth of the crown and its gradual passage into the root, it agrees
with the human tooth and differs from that of the Chimpanzee, in
which the crown is very brachyodont and overhangs the root. As
a human molar it is unusual in the feebleness of its cruciform fis-
sure, and in the presence of the slight depression on the crown
behind the postero-internal and fifth cusps ; but both these features.
are approached in the Melanesian tooth selected for comparison
(Pl. 1, fig. 6a). In the antero-posterior elongation of the crown ~
and in the characters just mentioned, it obviously resembles the
corresponding tooth of the Chimpanzee (fig. 8a); but the cusps in
the latter are so brachyodont that much larger areas of dentine are
exposed when they are worn down to the level reached in the fossil.
These comparisons are made because it has been stated that the
molar teeth in the Piltdown mandible are those of a Chimpanzee !:
reference to the teeth of other known Apes is not necessary.

The following are the extreme measurements (in millimetres)
of the teeth taken between the convexities of the sides :—

Melanesian. Tasmanian. New Tooth. Chimpanzee.
Denergar 65.22 Suk 13 13 12
Widder eres tu 4155 11°5 4 10°5

The following are similar measurements of the two lower molars
in the original specimen of Hoanthropus dawsont :—

Mi: M,.
Pemeinet) >) | tothe. Sane eee 12°5 13
Width, ' 9 cr. be Ses 22 eee 13

From the new facts now described it seems reasonable to conclude
that Hoanthropus dawsoni will eventually prove to be as definite
and distinct a form of early Man as was at first supposed; for
the occurrence of the same type of frontal bone with the same
type of lower molar in two separate localities adds to the probability
that they belonged to one and the same species.

Again I have to thank the Lord of the Manor, Mr. G. M. Maryon
Wilson, and the tenant of Barkham, Mr. Robert Kenward, for
facilities in continuing the exploration of the Piltdown gravel-pit.
I am also indebted to Mr. C. G. Turner, of Uckfield, for much
kind service. Finally, I desire to thank my colleague, Mr. W. P.
Pyeraft, A.L.S., for his valuable help in making comparisons with
the osteological collection under his charge.

1 G. S. Miller, ‘ The Jaw of the Piltdown Man’ Smithson. Miscell. Collect.
vol. Ixy, No. 12 (1915). Endorsed by W. K. Gregory, ‘Studies on the Evolu-
tion of the Primates’ Bull. Amer. Mus. Nat. Hist. vol. xxxv (1916) pp. 313-20.
Replied to by W. P. Pycraft, ‘ The Jaw of the Piltdown Man’ Science Progress,
No. 43 (1917) pp. 389-409.

part.1] | SECOND SKULL FROM THE PILTDOWN GRAVEL. 7

EXPLANATION OF PLATE I.
[All the figures are of the natural size. |

Fig. 1. Eoanthropus dawsoni A. S. Woodward. Inner supraorbital portion
; of right frontal: outer view (1 a); inner view (1 6); section along
sagittal crest (1c); and section at outer edge (ld). a.=air-sinus ;
c.=frontal crest; n.=supraorbital notch ; s.=supraciliary ridge.
2. Hoanthr opus dawsoni. Middle portion of occipital: outer view (a) ;
inner view (b); and vertical median section along external
occipital crest (c). cb.=cerebellar fossa; cer.=cerebral fossa ;
e.0.c.=external occipital crest ; i gupta cane occipital crest ;
v.c.l.=i1nferior curved line ; l.si.=groove for lateral sinus ; s.c.l.=
superior curved line; t.=groove above torcular Herophili. °
3. Pmeeiopus dawson. Vertical median section of the occipital bone
of the type-specimen along the external occipital crest. Lettering
as in fig. 2, with addition of i.=inion.
4. Eoanthropus dawson. Left first lower molar: crown (a); outer (b),
inner (c), posterior (d), and anterior (e) views.

5. Hoanthropus dawsoni. Right first lower molar of the type- specimen,
anterior view.

6. Left first lower molar of Melanesian: crown (a); outer (b), inner (c),
posterior (d), and anterior (e) views.

7. Left first lower molar of Tasmanian: crown (a); outer (b), inner (c),
and posterior (d) views.

8. Left first lower molar of large Chimpanzee: crown (a); outer (b),
inner (c), posterior (d), and anterior (e) views.

APPENDIX.

On the Form of the Frontal Pole of an Endocranial Cast of
Eoanthropus dawsont.

By Prof. G. Extiot Suir, M.A., M.D., F.R.S.

Although the fragment of the right side.of the frontal bone
reveals the form of only a small area (little more than 5 em. long
x 3 cm. broad) of the endocranial surface, which is devoid of
obtrusive features, it is of interest and importance because it sheds
some light upon a part of the endocranial cast of which nothing
was known before. Moreover, it is a part of the cast, the frontal
pole, the form of which is of peculiar significance in the study of
the features of early Man.

In a communication dealing with the endocranial cast of the
Boskop skull, which I presented to the Manchester Literary &
Philosophical Society last month,! I called attention to the small
size and lack of roominess of the prefrontal region of the cranial
cavity in Neanderthal man, and made special use of the form and
relative size of the prefrontal area of the Boskop cast to establish

1 This will be published in the Transactions of the Royal Society of South
Africa.

8- PROF. G. ELLIOT SMITH ON A [vol. xxiii,

the fact that the skull from which it was obtained conformed to
the modern type (by some authorities regarded as the species

Homo sapiens, as distinct from H. neanderthalensis).
The small fragment of endocranial cast now under consideration
presents at its medial border about 4°5 centimetres of the broad
deep median furrow, corresponding to the endocranial sagittal crest
of the frontal bone; and below, part of the orbital margin, although
not sufficient to display the form and extent of ‘the orbital rostrum.
There are no distinct indications of the situations of any of the
cerebral sulci, although there is a definite flattening of the surface
parallel to, and about 1 centimetre above, the orbital margin.
Passing upwards from the

Fig. 2.—The frontal pole of an middle of this flattening is
endocranial cast of Eoan- ® ven (fig. 2 ks ae aa
e on ression ee ;

ee fgaui ee ir es seitially at a distance of about

2 centimetres from the median

plane. The surface between
this depression and the median
groove is raised up into a pro-
minent hillock (aa), the exact
analogy for which I have been
unable to find in any human
brain or cranial cast. It pre-
sents a much closer analogy to
the condition found in the casts
of skulls of the Neanderthal
series (more especially the Gib-
raltar, Neanderthal, and la
Quina casts) than in those of
any more recent varieties of
man. But it suggests also the
paramedian ridge formed — by
the anterior part of the superior
frontal convolution in the an-
b “sedat thropoid apes, the prominence
|@ = paramedian eminence; b = de- ree ere Ae eh
pressed area at the lateral border : bi. ae Se z & .

of the eminence; c = part of the falling away of the ill-deve-
fronto-orbital margin. | loped lateral part of the pre-

frontal area.

If these tentative suggestions are justified, this small fragment
affords further corroboration of the opinion that I expressed with
reference to the endocranial cast of the Piltdown skull: namely,
that it presents features which are more distinctly
primitive and ape-like than those of any other member
of the human family at present available for exami-
nation.

Quart. Journ. GEOL. Soc. Vor. LXXIII, Put.

a
2
7)

Bemrose, Colio.,, Derby.

DAWSONI.

HROPUS

Quart. Journ. Geor. Soc. Vor. LXXIII, Pu. I.

G.M. Woodward, del. Bemrose, Colla, Derby,

EOANTHROPUS DAWSONI.

|
part 1] SECOND SKULL FROM THE PILTDOWN GRAVEL. 9

DISCUSSION.

Mr. W. P. Pycrart exhibited a specimen of the right half of
a mandible of a chimpanzee, sent to him for examination by
Mr. Gerritt T. Miller, of the Smithsonian Institution, Washington.
Mr. Miller, in his Memoir on the Piltdown jaw, Jaid no little
stress on the importance ot this specimen, from the fact that the
molars are worn so as to present flattened crowns similar to those of
the Piltdown jaw. Hence, this specimen formed a link in his chain
of evidence that the Piltdown jaw was unquestionably that of a
chimpanzee.

It is clearly the jaw of an adult of one of the small races of
chimpanzee, and apparently of'a female. But, as a witness for
Mr. Miller, it must be held to have failed ; because, although the
molars are worn flat, this is due, not to normal wear, but to some

interference in the normal ‘bite’ of the jaw caused by the _ .

abnormal position of PM,, which projects above the level of
the worn surface of the molars as much as 5mm. That this is
not due to post-mortem displacement is clear, since the posterior
border of the crown, where it impinges upon the anterior border
of PM., shows no sign of facetting as a consequence of the
mutual pressure of the two teeth. Nor does the crown show any
sign ot wear. Unfortunately about half of this is missing, the
tooth } having split longitudinally.

"The second premolar shows but very slight signs of wear, and is
conspicuously flat-topped—a feature peculiar to the tooth rather
than due to wear.

The first molar is, as Mr. Miller described it, worn to a flat-
topped surface, but the wear has been from in front backwards, so
that the crown presents a decided backward. slope when seen in
profile.

The surface of M,, though worn flat, is not in the same plane as
that of M,. This much can easily be demonstrated if a straight-
edge be placed over the two teeth; a large wedge-shaped gap will
then be found between the straight- edge “and M,, the apex of the
wedge being pointed forward. The worn surface of this tooth (M,)
is not absolutely flat, but presents a shallow depression running
from the entoconid obliquely forwards to the protoconid.

The incisors have been worn down to about half their original
length.

In no other chimpanzee that the speaker had examined had he
ever found anything in the matter of wear comparable with the
molars of Mr. Miller’s specimen. ‘These are quite abnormal in this
regard, and therefore of no value as evidence that the Piltdown
teeth might, even in the wear of their crowns, agree with teeth of
chimpanzees. Normally, one might affirm that the molars of these
animals never wear flat; but the outer cusps disappear before the
inner cusps are perceptibly reduced by wear.

10 _) SKULL FROM THE PILTDOWN GRAVEL. — [vol. Ixxi,

Prof. A. Kerru said that these further Piltdown ‘finds’ estab-
lished beyond any doubt that Koanthropus was a very clearly-
differentiated type of being—in his opinion a truly human type.
He agreed with “Dr. Smith Woodward and Mr. Pyeraft that the
lower molar now found and the original mandible ‘and teeth must
be ascribed to Hoanthropus, and “constituted the characteristic
features of the type. He did not think that the relationship of the
external occipital protuberance to the position of the lateral venous
sinuses had any great value in the differentiation of human species.
Among modern English skulls it was not uncommon to find the
external occipital protuberance above the level of the lateral sinuses,
as in the newly-found fragment. The position of the protuberance
changed with age, and it ascended on the occiput as the- neck
expanded; it was low in position in women and children, and high
in men with thick necks. The high position of the protuberance
in the specimen found either indicated that it belonged to an older
individual than the type-specimen, or pointed to a difference of sex.
The frontal fragment was a particularly valuable addition, because
it cleared up any doubt as to the contour of the forehead over the
root of the nose. The supraciliary parts of the supraorbital bar
were but slightly prominent, there being a wide shallow depression
separating the right and left supraciliary eminences. The depth
and thickness of the internal frontal crest were altogether
remarkable.

Sir Ray Lankester said that all must appreciate the clear and
interesting statement made by Dr. Smith Woodward. He con-
oratulated the Author on the gradual addition, by his patient work
pad that of the late Mr. Charles Dawson, of new bits to our
knowledge of the Piltdown man. He pointed out that it was a
possibility —although highly improbable—that the piece of the
frontal bone and also the molar tooth now described belonged to
the same individual as that represented by the imperfect skull
and lower jaw already known. But this was not true of the
fragment of the occipital bone, since the region corresponding to
this fragment was present in the imperfect skull now in the
Natural History Museum. The present ‘find’ therefore makes
it impossible to regard the Piltdown man as an isolated abnormal
individual. The fragments hitherto found must be referred to two,
and possibly to three or even four individuals.

Mr. W. Date observed, with regard to the flint that was said to
have been used as a hammer-stone, that it had probably sunk down
from a higher level and was of newer date. Ata previous meeting
on the same subject, palzolithic implements had been shown which
were of the deep-ochreous eolour of the bones. This ‘ hammer-
stone’ was scarcely patinated at all.

Dr. A, SmrrH Woopwarp thanked the Fellows present for their
reception of his paper, and mentioned that the new specimens of
Eoanthropus exhibited had been presented by Dr. F. DuCane
Godman to the British Museum.

part 1]. _ LOWER CARBONIFEROUS SPILITES. | 11

2. On a Sprniric Factes of LowER Carsonrrerovs Lava-F Lows
am DERBYSHIRE. By Henry CrunpEen Sargent, F.G.S.
(Read February 7th, 1917.)

CONTENTS.

Page

PP CrMoinehiM se eee wire cS TR ea ee A se Bal
col Line [CERNE Oa ood 6 Ne a Se a ee an a 12
iimebhe Associated ROCKS 20... 0 20. leek ee cease delonswndeen 1
iMerresrogenetic Considerations... ..............2. dees ceewaccce aes 19
V. Analyses ...... < Sb HSE Gh YL ee nee arly ert h RARE Deee PN 21
OT UE LGrE “LD TSUENS (i 952 A nn eG! Oc E 22
wean summary of Conclusions .............0..5.. lies ce vcenceeceses: 23

I. InrRopDucTION

THE igneous rocks of Derbyshire, locally called ‘toadstones,’ form
a well-known basic series comprising Java- flows, sills, a few thin
dykes, and also, in many localities, pyroclastic material varying
from coarse agglomerate to fine-grained tuff. All these rocks occur
entirely in beds of Lower Carboniferous age. The lava-flows and
ashes were contemporaneous with the Carboniferous Limestone,
with the exception of a few small occurrences in the south-west of
the county which are in the Limestone Shales overlying the lme-
stone. ‘That they were submarine is evident trom their intercalation
at various horizons in marine deposits. There would appear to have
been a large number of vents scattered over a sea-floor that was
undergoing slow and prolonged subsidence.

Dr. Bemrose ! has classified the lavas and sills under three heads,
namely: (1) olivine-dolerites, (2) ophitic olivine-dolerites, and (3)
olivine-basalts. These distinctions rest on internal structure alone,
and not on mode of occurrence, intrusive or extrusive.

In the course of a visit of the Geologists’ Association to Derby-
shire in the summer of 1914, specimens of lava were collected in
Tideswell Dale which appeared, on examination under the micro-
scope, to vary widely in character from the dolerites and basalts of
the county hitherto described. Dr. Harker, to whom a thin section
was submitted, pointed out that it possessed decided affinities with
the spilites of Devon and Cornwall, and also, to some extent, with
the mugearites of East Lothian. It seemed desirable, therefore,
to make a further examination of the rocks of the district, in order
to ascertain to how great an extent these features occurred _else-
where, and the object of this paper is to record the result.

I desire to express my great indebtedness to Mr. A. T. Metcalfe,
F.G.S., who was the first to note the special features of the
Tideswell- Dale rock and urged me to undertake the investigation.

1Q. J. G. S. vol. 1 (1894) p. 624.

12 MR. H. C. SARGENT ON LOWER CARBONIFEROUS [ vol. ]xxiu,

II, Tue Lavas

The features of the Tideswell-Dale rock that directed attention
to the subject were (a) the abundance of oligoclase among the
felspathic constituents: (0) the occurrence of albite in the vesicles ;
and (c) the subordinate part played by augite as compared with
olivine. Many specimens from other areas of the county have now
been examined under the microscope; and, although from numerous
exposures, Dr. Bbemrose’s petrographical description ! is fully borne
out, there are many from various localities which possess features
similar to those of the Tideswell-Dale rock. Such localities as have
been hitherto noted by me are set forth in the accompanying list,
and it will be seen that all the main flows of the county, as mapped
by Dr. Bemrose, are represented, as well as several of those which
he describes as ‘ uncorrelated.’ * With the exception of Kniveton,
all the localities are in the Carboniferous Limestone.

Locality. Horizon.
1. Ball Eye, Via Gellia, near Cromford. | ( Upper Lava.
2 Salter’s duane, Matlock......5:...4.. |. Dowie
3. Masson, Matlock ............ Aare | Do. do.
4. Dobb Lane, Bonsall © oo.) 23.0.6 5. ‘Matlock Area ...... + Lower Lava.
5. Mmber Lane, Bonsall oe... 215k | Do. do.
6. Aldwark Grange, near Grange Mill. | Uncorrelated.
7. Sacheveral Barn, near Grange Mill. } \.' Siies
8. Knot Low, Millers Dale ............ Upper Lava.
OP ides well Dale «oie. tas. oscee saan Mallers Ionia aes Lower Lava.
10. Tideswell Dale ......... stat yh Noe : Uncorrelated.
11. New Bridge, near Ashford . ae ee Do.
12. Conksbury Bridge, Lathkill Dale. _ Upper Lava of Lathkill Dale.
13. Bradford Dale, Youlgrave ......... Gee a ee ( Uncorrelated.
14. Lumford Mill, near Bakewell ...... .) po.” Do.
TAY Orc] cal O) 1h i alegogel Mtns eet eee eee ee eee Doubtful.
16. Kuniveton ©2002. 00...0.20 ee.” Wssington Area?) iia
Shales.

In both macroscopic and microscopic characters the Derbyshire
lavas show a rather wide range. Their colour varies from different
shades of grey, green, or blue, to black. Their texture may be fine-
grained or coarsely crystalline, with gradations from one extreme
to the other.

The rocks with which this paper is concerned belong to the
leucocratic end of the series. They are nearly always vesicular
and always intensely altered. Both olivine and augite appear to
have been invariably present in the original rock, the former
sometimes preponderating over the latter, as already noted in
the Tideswell-Dale specimen; but, under ‘the microscope, both
minerals are always seen to be completely destroyed. The
evidence of their former presence consists in a more or less com-
plete recrystallization, pseudomorphous or otherwise, of secondary
products such as calcite, quartz, and minerals of a chloritic or

1 Q. J. G.S. vol. 1 (1894) pp. 611-25.
2 Ibid. vol. lxiii (1907) pp. 247 & 251.

part 1] SPILITES IN DERBYSHIRE. 13

serpentinous character, often with radial and spherulitic structures.
Iron-ores, both magnetite and ilmenite, are generally abundant.

But, amid the general wreck of the other constituents, the felspars
stand out conspicuously as much less altered. They retain their
erystal-form, though their edges are always ragged and corroded.
Their interiors, when original, are clouded with alteration-products ;
but not seldom they are quite fresh and water-clear, apparently as
the result of a replacement of the original felspar-substance by
secondary material.

In all the localities named above the felspathic element pre-
dominates, and not infrequently forms the bulk of the rock. It
oceurs as phenocrysts, laths, or microlites, and sometimes in allo-
triomorphic interstitial fragments. In general, porphyritic struc-
ture is not very noticeable, and it is often absent. In a few
localities large felspar-phenocrysts abound [1; 13]. In many of
the thin sections the felspar-content is seen to consist wholly of
laths of fairly uniform size, and in a few it is almost entirely
microlitic (9; 11; 16]. The species, too, show a rather wide range.
Oligoclase appears to be always present among the laths and
microlites, and sometimes it is the dominant felspar. Its identity
is known by the extinction-angles which, in sections normal to
the albite-lamellz, range from zero to 6°; and by the refractive
index which, when it can be compared with that of the balsam, is
seen to be about the same, or a very little higher. More often than
not, comparison with the index of the balsam is obscured by
alteration-products in the felspar. Subordinately, a more basic
plagioclase occurs among the laths, and this may generally be
referred to andesine or to an acid labradorite. When phenocrysts
of original composition are present, they are often more basic
than the felspar of the ground-mass, and belong to the andesine-
labradorite series. .

In addition to plagioclase there is undoubtedly a considerable
proportion of potash-felspar, which is assumed to be orthoclase
and is often of a secondary character, in these rocks. Sometimes,
when a large amount of replacement of the original laths has
taken place, it becomes the dominant species [2; 3]. This view
is borne out by both the microscopic examination and the analyses.
Carlsbad twins extinguishing simultaneously when parallel with
the cross-wires occur in both phenocrysts and laths, and untwinned
erystals extinguishing straight are seen in many of the sections.
Very low refractive indices, lower than that of the balsam, may
be seen in many of these individuals. Shapeless fragments of
felspar-substance, probably orthoclase, also occur interstitially in
some of the sections.

Zoned felspar- crystals are not uncommon, a thin outer zone less
basic than the interior and with straight extinction being often seen
on the laths.

1 Numbers in square brackets refer to the localities enumerated in the list
on p. 12.

14 MR. H, C. SARGENT ON LOWER CARBONIFEROUS _ [ vol. Ixxiii,

Dr. Bemrose has noted that, in specimens from three outcrops
examined by him,
‘the ground-mass sometimes consists of a small felt of felspar-laths often
giving parallel extinction.’ !

It is interesting to contrast these rocks with those at the other
end of the series, the darker rocks which are of normal basaltic or
doleritic type. It is unnecessary to describe these in detail, since
Dr. Bemrose has already done so®; but a point of importance
bearing, as I conceive, on the evolution of the whole series, is their
general freshness as compared with the rocks above described. They
are sometimes beautifully fresh and well preserved, the principal
sign of alteration being slight serpentinization of the olivine.

A more detailed description of a few of the more noteworthy
rocks with spilitic affinities may now be given. This will be mainly
confined to the felspathic content, since the general description of
the other constituents given above holds good for all.

In the rock from Ball Eye, Via Gellia { 1], the felspar occurs in
two generations: large lath-shaped phenocrysts and a ground-mass
of microlites. Many of the phenocrysts are twinned on the albite
law, and show extinction-angles which point to andesine-labradorite.
Carlsbad twins with simultaneous or unsymmetrical extinctions,
and untwinned crystals extinguishing straight, also occur in sub-
ordinate quantity. The microlites of the ground-mass appear to
be dominantly oligoclase. Very little, if any, replacement by
secondary felspar has taken place here.

The Salter’s Lane and Masson rocks [2 & 3] are both outcrops
of the Upper Lava of the Matlock area. The former was collected
in situ; the latter was obtained from the waste -heaps of the Seven
Rakes Mine, now closed. The rock is sub-porphyritic, the felspar-
content consisting of a few small phenocrysts and a mass of laths
of fairly uniform size. The phenocrysts are altered throughout
to a water-clear felspar-substance associated with patches of calcite.
The laths are sometimes similarly altered ; but often the secondary
felspar is seen on the margins only, the interior forming a spongy
core of chlorite and calcite. Vestiges of albite-twinning occur in
some of the laths, and the secondary calcite suggests that labradorite
was originally present. The secondary felspar has a lower refractive
index than the balsam, and in view of the analyses (Nos. VI &
VII, p. 22) it must be assumed to be orthoclase.

x

The lava-flow on Knot Low, Millers Dale [8], is about 120 feet
thick. At the summit the rock below the zone of atmospheric
weathering is a fresh basalt; at the base it is of spilitic character,
and is altered throughout. It is non-porphyritic; the felspars are
all lath-shaped, frequently untwinned, and sometimes twinned on

1 Q. J. GS. vol. 1 (1894) p. 624.
2 Ibid. pp. 611-25.

partl] — SPILITES IN'DERBYSHIRE. © - - 15

the Carlsbad law. Extinctions are straight, or with a very low
angle. .

The Tideswell-Dale flow [9] is well seen in a small disused quarry
directly south of the North Fault, as mapped by Dr. Bemrose,1
where the specimens mentioned on p. 11 were collected. Both
vesicular and non-vesicular rocks are well exposed. The former
has already been briefly described: it consists mainly of a mass
of felspar-laths and microlites with flow-structure. They appear
to be chiefly oligoclase, but subordinate andesine also occurs.
Felspar-phenocrysts are absent.

In the non-vesicular rock, which overlies the vesicular portion,
large felspar-phenocrysts are very abundant.- The transition from
non-porphyritic to porphyritic rock is absolutely abrupt, and a
clear line of demarcation, marked by the greater alteration of the
underlying vesicular rock, is well seen. “There can hardly be a
doubt that the porphyritie rock is a distinct flow from the under-
lying spilitic bed. Its phenocrysts are frequently very long and
lath-shaped. Untwinned individuals occur among them, and these
have straight extinction ; but most of the crystals have extinction-
angles which show that a felspar predominates which is more basic
than that in the vesicular portion of the exposure. The dominant
species appears to be andesine, but subordinate oligoclase also
occurs, and probably some orthoclase as well. Augite is present in
fairly. fresh condition, moulded on the felspars, and it is clear that
this bed does not come within the range of the spilitic type of
these lavas. Nevertheless, here too, replacement of the original
felspar by alkali-felspar appears to have commenced along c1 racks
and fissures in the phenocrysts.

The lava of Crich Cliff [15] can now be collected only on the
waste-heaps of abandoned mines.. Examples of both types of
rock may be found. The comparative freshness of the
basalts is very striking, when compared with specimens having
spilitic affinities. In the former granular augite is abundant, and
remains of unaltered olivine may be seen. A few felspar-phenocrysts
occur, but the bulk of the felspar-content is in the form of laths.
Extinction-angles indicate labradorite as the dominant species; but

-untwinned water-clear crystals, with straight extinction and appa-

rently of secondary origin, occur in subordinate quantity. In
specimens with spilitic affinities from the same waste-heaps the
dominant original felspar is sometimes oligoclase, sometimes ande-
sine- labradorite ; but replacement on a considerable scale has taken
place, and the other constituents are always destroyed. Here, too,
untwinned laths and Carlsbad twins with straight extinction occur.

The lava of Worm Wood, near Bakewell, is a good example of
a rock mtermediate between those of spilitic type and the true

1 Q, J. G. S. vol. lv (1899) map, pl. xix.

16 MR. H. C. SARGENT ON LOWER CARBONIFEROUS | vol. lxxiul,

basalts. The phenocrysts here are entirely replaced by alkali-felspar
enclosing small patches of secondary calcite, which probably indicate
labradorite as the original felspar. They are twinned on the albite
law, and have extinction-angles indicating andesine or an acid
labradorite. Their refractive index is higher than that of the
balsam. Messrs. E. B. Bailey & G. W. Grabham’s observation !
that, in a porphyritic basalt, the phenocrysts are always attacked
before the less basic felspars forming the ground-mass, is thus .
confirmed here, as well as elsewhere, in the Derbyshire rocks.

The study of the vesicles affords matter of much interest.
Frequently they are lined with a very thin layer of a fibrous
green chloritic substance, the fibres standing out from the wall of
the cavity. The birefringence of this mineral is higher than that
of chlorites in general. The following minerals occur in the interior
of the vesicles, generally two or more together: quartz, chalcedony,
calcite, dolomite, albite, and chlorite. The sequence observed in
the deposition of these minerals varies in different vesicles.
Granular quartz frequently occurs in small grains or narrow strips
associated with the outermost chloritic lining, or itself forming the
actual lining of the cavity. When quartz and calcite are associated,
the quartz has generally separated out before calcite. Rarely, the
reverse is the case, and dogtooth crystals of an outer zone of calcite
are seen penetrating an inner zone of quartz. Dolomite is often
associated with calcite. Helminth is the most abundant form
of chlorite, and there is sometimes present a yellowish-brown fibrous
mineral, pleochroic and with low birefringence, which may be near
delessite. Sometimes these chloritic minerals fill the entire vesicle,
or, in a composite amygdale, they may be formed at any stage
relatively to the other minerals in the vesicle. In the vesicles
described by Messrs. Bailey & Grabham?a regular sequence of
deposition occurs, namely: (@) albite, (6) chlorite, and (¢) calcite.

It is clear from the foregoing description that there is a facies of
lava-flows in Derbyshire presenting characters widely different from
those of the true basalts. That they have structural trachytic
affinities is obvious from the predominance of alkali-felspar con-
sisting of a mass of laths and microlites, sometimes exhibiting
fluidal arrangement and often forming the bulk of the rock. On
the other hand, they are essentially more basic than the trachytes,
as is shown by their low silica-content, their abundant iron-ores,
and the presence of olivine.

There is no need to emphasize the points of resemblance and
difference between these rocks and those of the spilitic and
mugearitic groups. Like the spilites, the Derbyshire rocks were
submarine flows in an area that was undergoing slow and prolonged
subsidence. Like both spilites and mugearites, their structure is

1 © Albitization of Basic Plagioclase Felspars’ (Geol. Mag. dec. 5, vol. vi
(1909) p. 251.
2 Ibid. p. 258.

part 1] SPILITES IN DERBYSHIRE. 17

trachytic and they are rich in alkalies. They are, however, dif-
ferentiated from the spilites of Cornwall by their abundant content
of olivine and the presence of orthoclase. On the other hand, these
features are characteristic of the mugearites.

Pillow-structure, again, has not been recorded among the Derby-
shire lavas, but this feature is probably dependent on accidental or
local circumstances. Mr. C. Reid & Mr. H. Dewey! have suggested
that it may, perhaps, result from some special physical capacity for
retaining bubbles of gas, and be quite independent of chemical
composition.

It is clear therefore, in view of the characteristic features of the
Derbyshire lavas described above, that, while they are intermediate
geographically between the spilites of the South-West of England
and the mugearites of the Lothians, they are also intermediate in
character. Their structure and field-relations appear to me to asso-
ciate them, on the whole, more closely with the former than with
the latter, and, in view of their outstanding peculiarity, it is sug-
gested that they may be appropriately termed potash-spilites.

It is interesting to note the striking resemblance between the
spilitic lavas of Derbyshire and some of the rocks of similar age
associated with the Carboniferous Limestone of the Bristol district.?
which appear to be also of spilitic type. The preponderance of
potash over soda is as marked there as in the Derbyshire lavas.
The average of five analyses of the Bristol rocks shows the follow-
ing percentages :—potash = 5-028, soda=0°854.3 There, too, as in.
Derbyshire, the rocks of spilitic type are associated with true
basalts.

Ill. Tuer Assocratep Rocks.

Just as the mugearites of Skye are associated with the Roineval
dolerites,t those of the Lothians with olivine-basalts,° and the
spilites of Devon and Cornwall with albite-diabases,6 so, too, in
Derbyshire, magmatic differentiation has produced similar results
which are seen in the association of the spilites of that county with
olivine-basalts. These have labradorite or a more basic species for
their dominant felspar; but, for the reason already noted, there is
no object in describing them here in detail.

The close association of spilites with jaspers and cherts, the

1 Q. J. G. S. vol. lxiv (1908) p. 268.

2S. H. Reynolds, ‘Further Work on the Igneous Rocks associated with
the Carboniferous Limestone of the Bristol District’ Q. J. G. S. vol. Ixxii
(1916-17) pp. 23-41.

3 Ibid. p. 38.

+ <The Tertiary Igneous Rocks of Skye’ Mem. Geol. Surv. Scotland, 1904,
pp. 262-64,

®> «The Geology of East Lothian’ [bid. 1910, pp. 122-23.

6 H. Dewey & J. S. Flett, ‘On some British Pillow-Lavas & the Rocks
associated with them’ Geol. Mag. dec. 5, vol. viii (1911) p. 206.

Q. J.G.S. No. 289. C

18 MR. H.C. SARGENT ON LOWER CARBONIFEROUS _ [ vol. lxxiii,

latter often said to contain radiolaria, is well known. Sir Archibald
Geikie! has pointed out this association in the case of pillow-lavas
in such widely scattered localities as Cader Idris, the Lizard, the
southern flanks of the Scottish Highlands, the North of Ireland,
Saxony, and California. Mr. Dewey & Dr. Flett? have recorded
the constant association of the Cornish spilites with radiolarian
cherts, which they ascribe to the escape and decomposition of the
soda-silicates in the igneous rock, whereby silica would become
available for assimilation by the radiolarian plankton.

The physical conditions of the Carboniferous Limestone sea were
doubtless, in general, unfavourable to the development of organisms
requiring silica for their tests; but an analogue to the Cornish
cherts is to be found in the silicified limestone or quartz-rock,
formed by the replacement of carbonate of lime by silica, which so
often occurs in Derbyshire in the areas of former volcanic activity.
These rocks have been described by Dr. Bemrose,? and he attributes
their occurrence to the action of deep-seated thermal waters holding
silica in solution. The liberated silica, which would seem to be a
necessary product of the intense alteration that the spilitic lavas
have undergone, would probably, unless 1t were borne away by
currents, contribute to this result. Volatilized silicates held in
juvenile gases, the later efforts of volcanic energy, would also
contribute abundant silica, which would be available for the for-
mation of quartz-rock. Ste.-Claire Deville and other investigators
have shown that ‘emanations of carbon dioxide mark the dying-out
of the voleanic energy,’ * and it seems probable that the reactions
originated by these components of juvenile gases would effect the
metasomatism in question.

Instances of the occurrence of quartz-rock in the immediate
neighbourhood of vents may be seen at Bonsall, close to the Ember-
Lane vent; and at Ashover directly over the tuff of that locality.
Near Bakewell, in close proximity to the Crackendale vent, there
are thick deposits of chert which may, almost without doubt, be
ascribed to similar agency. The same observation applies to the
chert which occurs so abundantly in the neighbourhood of Castleton,
again in close proximity to the scene of volcanic activity. In the
limestone of the Crich inler there are thin partings consisting
entirely of microscopic crystals of quartz.

Evidence in support of the view that the metasomatism resulting
in the Crackendale type of chert is due to agents of volcanic origin
may be found (apart from the fact that it appears to occur always
in the area of former volcanic activity) in the presence of streaks
and patches of crystalline calcite and fluorspar embedded in the
chert, and also in the development, in cavities, of quartz-crystals

? ¢ Ancient Volcanoes of Great Britain’ vol. i (1897) p. 193.

2 Geol. Mag. dec. 5, vol. viii (1911) p. 245.

3 Q. J. G. S. vol. liv (1898) pp. 169-82.

4+ See F. W. Clarke: ‘The Data of Geochemistry’ Bull. U.S. Geol. Surv.
No. 616, 3rd ed. (1916) p. 262.

part 1] SPILITES IN DERBYSHIRE. 19

such as are never seen in the normal black chert so abundant in
nodules and thin layers in the upper beds of the Carboniferous
Limestone of Derbyshire. In the Crackendale chert-beds, too, all
the original organisms of the limestone appear to have been
entirely destroyed, although in the limestone above and below the
chert fossils are abundant. The chert-beds at the Holme-Bank
Mine have an average thickness of 4 feet, and the rock is white
or grey in colour: it is mined for use in the Potteries.

-TV. PETROGENETIC CONSIDERATIONS.

The form of alteration to which the Derbyshire spilites have
been subjected obviously is quite different from that which results
from ordinary weathering, and appears to be clearly in the nature
of autometamorphism. All the available field-evidence that I
have hitherto noted tends to show that the spilitic rocks generally
underlie (in the same bed) those of more basaltic type, and it is
sometimes possible to observe a progressive upward variation. This
has already been noted in the description of the lavas on Knot Low
and in Tideswell Dale.

These observations agree with those recorded by other investi-
gators, from Charles Darwin! (more than seventy years ago) to
Prof. P. Marshall? in his paper read before the Geological Society
in May 1914, to the effect that, where alkaline and calcic lavas
proceed from the same orifice, the former have generally been
erupted first.

It is not claimed that the Derbyshire spilites are of extreme
alkaline type; but it is suggested that, in considering their genetic
relations to the associated basalts, we may premise a magma of
which the upper part was richer in gases and in the more easily
‘sublimable constituents, including the alkalies, than the remainder,
and that, as this upper. portion was drawn off, the later erupted
material would tend to become increasingly caleic. The constantly
vesicular nature of the spilites is sufficient proof of the presence of
a large amount of gases and residual water.

That no general stratification of the magma, due to the action
of gravity, took place prior to eruption is, however, clear from the
fact that the earliest flows, the spilites, always contain a notable
proportion of the first-formed minerals—olivine and iron-ores.

Without entering on the vexed question of the origin of alkaline
rocks in general, on which so much has been written of late years,
I may point out that the relative enrichment in alkaline con-
stituents of the upper part of the magma, postulated above, is
probably assignable to the upward passage through the magma
of gases carrying with them a considerable portion of the alkalies

1 “Geological Observations on the Volcanic Islands’ 1844, p. 118.
2 Q. J. G. S. vol. Ixx (1914) pp. 382-406.

c2

20 MR. H.C. SARGENT ON LOWER CARBONIFEROUS _ [ vol. ]xxin,.

in a volatile state. Prof. R. A. Daly! cites strong corroboration.
of his view that

‘the abundant soda of a spilite has been concentrated from an underlying mass.
of normal basaltic magma’

by gaseous transfer of the albite molecule. Dr. F. W. Clarke? is.
also of opinion that

‘the magmatic vapours must exert an important influence upon the process of
differentiation, for they tend to accumulate in the upper part of a lava eolumn
or reservoir and to modify its properties locally.’

A -further consideration, which appears to have an important
bearing on the evolution of the spilites, is the effect of the physical
environment of a submarine flow. It is generally recognized that
the pressure of the superincumbent mass “of water on the molten
rock. would effect the rapid formation of a thin crust on its surface,
with the twofold result that its internal heat would be retained
longer than in the case of a subaérial flow, and the release of the
volatile constituents would be impeded. |

The presence of hot alkaline solutions thus retained and cireu--
lating among the earlier-formed minerals affords a ready explana-
tion, as has been noted by other observers, of the intense alteration
seen in the spilites. Post-voleanic or juvenile emanations have also:
been invoked, but retained residual solutions, especially in the case
of outcrops far removed from any recognizable vent, seem quite-
sufficient for the purpose.

It has been already pointed out that the basalts, which were
erupted later than the spilites, are often beautifully fresh, although
they have, of course, been subjected to the same external qtigenees
since eruption as the spilites. This affords further evidence that
the alteration of the spilites cannot be due to weathering. , It
appears, rather, to be the final stage of consolidation.

The infilling of the vesicles presents features which, it is sug--
gested, may be referred to the prolonged retention of a high
temperature in the lava after effusion. It has already been stated
that the vesicle-minerals are chlorite, albite, quartz, chalcedony,
calcite, and dolomite. Seeing that augite was one of the latest
minerals to consolidate, it is probable that the hydrated residue
contained augite-forming bases, and thus the earliest-formed
chlorite, the lining of the vesicles, which differs widely in character
from the helminth and delessite formed at later stages, may,
perhaps, be regarded as a primary mineral. This seems to be the
view advocated by Mr. James Strachan.*

The amygdaloidal albite, too, may also be regarded as a primary

1 «Toneous Rocks & their Origin’ 1914, p. 339.

2 «The Data of Geochemistry * 3rd ed. (1916) p. 311.

3 <The Carnmoney Chalcedony: its Occurrence & Origin’ Proc. Belfast
Nat. Field Club, vol. ii (1906).

part 1] SPILITES IN DERBYSHIRE. 21

mineral, since there can be little doubt that the hydrated residue
‘contained all the elements: necessary to its formation. The occur-
rence of amygdaloidal albite is somewhat rare: in the Tideswell-
Dale rock, when it occurs in the vesicles, this albite forms the
entire infilling, with the exception of the thin chloritic lining.

The other infilling minerals are all clearly of secondary origin,
resulting from the breakdown of the ferromagnesian constituents.
They are, moreover, all minerals that may be formed at fairly high
temperatures, and it is noteworthy that no hydrated minerals that
are formed at lower temperatures than albite, such as zeolites of
various species, and prehnite, are present (so far as my observation
goes) in any of the Derbyshire lavas, whether spilites or basalts.
The synthesis of both albite and orthoclase has been effected by
various investigators at about 500° C.1

Mr. W. F. P. McLintock? has* shown that in the vesicles of
Beinn Fhada (Mull) the order of deposition, apart from chlorite,
which there, too, may be formed at any stage, was: albite, epidote,
prehnite, scolecite. ‘These vesicles were evidently filled under
conditions of falling temperature; for, with rising temperature,
occasioned by an intrusion of eranophyre, the metamorphic changes
in lime-bearing silicates resulted in the production of minerals in
the reverse order: scolecite, prehnite, epidote, garnet. Since all
the elements necessary to the formation of minerals of the zeolitic
class so frequently found in basalts were undoubtedly present in
the residual solutions of the Derbyshire lavas, either as primary
constituents thereof or as alteration-products of the earlier-formed
minerals, ‘the inference seems to be justified that the consolidation
and the autometamorphism of the Derbyshire spilites were both
‘completed before the temperature fell much below 500° C.

V. ANALYSES.

Analyses of two of the spilitic lavas of Derbyshire are given
on p. 22 (Nos. IV & V) and partial analyses of a third (Nos. VI &
VII). For comparison, analyses of a mugearite and two spilites
are also quoted. Such intensely altered rocks as these cannot, of
course, be expected to show the composition of the original rock,
INey ertheless, it is clear that we are dealing here with essentially
basic rocks rich in alkalies, especially potash, but much altered
with production of carbonates and hydrated secondary material.
If we assume the carbon dioxide to be combined with lime in the
form of calcite, an assumption which is borne out by the micro-
scope, it will be seen that there is very little lime left for lime-
felspar.

' See C. Deelter, ‘Minerogenese & Stabilitaitsfelder der Minerale’ Tscher-
mak’s Min. Petr. Mittheil. vol. xxv (1906) p. 103; also F. W. Clarke, ‘The
Data of Geochemistry’ Bull. U.S. Geol. Surv. No. 616, 3rd ed. (1916) p. 366.

2 “On the Zeolites & Associated Minerals from the Tertiary Lavas around
Ben More (Mull)’ Trans. Roy. Soc. Edin. vol. li (1915) pp. 24-30.

22 MR. H. C. SARGENT ON LOWER CABBONIFEROUS _ [ vol. lxxiu,

| eh (nel 0 eer Ph ap 2 dah Fe Ae Vu. |
| | |
eA sincyetseet 49924 | AT56 | 4055 | 43-13 | 47°03
807 ae |} 1584 | 1427 | 1665 | 93°25 | 20-45 | |
Wee iid y 609 | 1°63 1S ee 7-00 | |
“BO hk Oke at Ge 946 | 4:81 : |
[0 Na eae ee 029 |; 030 O:20 | times fr t
Mee 302 | 4:90 5°20 6°50 8°79 | [
en eee | 526 | 1095 | 606 | 558 | 2°92 | |
Our we 5S [BL 461 | ave 360 263 082 12 |
EEO ek. OO C2 ooy) |) aoe a eee 659 55 |
Te Mahe ae | 1:84-) 2°40 | 295 © not est.| not est. |
| COs bine ah 2°95 | 7°85 3°50 | 190 | |
H120 (yarose 1:08 | 042 | 027 4:06, 90) ae |
A HAD (comb:)...| P61) 5), 265.4) (3°89 376 |} 365 |
| Other con- at rel ’ :
| ee: ; 177 | 034 0-90 ee
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| 10092 |

| Totals ..., 10053 100:25 | 100714 100°10 |
ores =
ee

——=

I. Mugearite, Druim na Criche, Skye (W. Pollard). ‘The Tertiary Igneous
Rocks of Skye’ Mem. Geol. Surv. Scotland, 1904, p. 2638.

Il. Spilite, Tregedden, South Cornwall (E.G. Radley). Quoted from H. Dewey
& J. S. Flett, ‘On some British Pillow-Lavas & the Rocks associated
with them ’ Geol. Mag. dec. 5, vol. viii (1911) p. 206.
IIL. Spitite, Devonport Workhouse Quarry (W. Pollard). ‘The Geology ef the
Country around Plymouth & Liskeard’ Mem. Geol. Surv. 1907, p. 97.
IV. Spilitic lava, Tideswell Dale (E. Smkinson).
V. Spilitic lava, Knot Low, Millers Dale (E. Sinkinson).
VI. Spilitic lava, Masson, Matlock. Partial analysis (E. Sinkinson).
VII. Spilitic lava, Masson, Matlock. Partial analysis (C. 8S. Garnett),

VI. Tue Turrs.

Although the scope of this paper is limited to the lava-flows, it:
is interesting to note that the tuffs, under the microscope, are not
infrequently seen to contain felspar-crystals with straight extine-
tion. Dr. Bemrose! records the occurrence of such felspars at the
following tuff outcrops: Cressbrook Dale, Monk’s Dale, Cracken-
dale, Ember Lane, Grange Mill, Woodeaves Vent. He also notes
the presence in specimens from Grange Mill of

‘a felspar-like a here and there in the lapilli which is biaxial, and may
be secondary albite.’

Water-clear, untwinned felspars also occur in some of these tuffs.
On the assumption that, when explosive action occurs, it takes place
at the commencement of the volcanic episode, we have thus further
evidence that the alkalies were to some extent concentrated in the
upper part of the magma.

1 Q. J. G. S. vol. 1 (1894) pp. 629-38.
*. Tbid. p. 635.

part 1] SPILITES IN DERBYSHIRE. 23

VII. Summary oF ConcLUSIONS.

(1) The lavas of Derbyshire, which are all of Lower Carboniferous
age, embrace rocks of spilitic or mugearitic type and basalts. Both
types have been derived from a common magma. The field-relations
hitherto ascertained indicate that, when they occur in association,
the spilitic rocks always underlie, and may grade upwards into, the
basalts.

(2) The differentiation was effected by the partial concentration,
prior to eruption, of the alkaline constituents in the upper part of
the magma, whither they were probably carried in a volatile state
by the upward movement of gases in the magma.

(3) The intense alteration “which the spilitic rocks have under-
gone was effected shortly after extrusion by hot residual solutions
belonging to the lava itself, and not by post-voleanic emanations
or weathering agencies.

(4) The deposits of quartz-rock and chert, which frequently occur
in Derbyshire in the neighbourhood of vents, are probably the result
of voleanic emanations of which it is difficult to define the precise
composition. ‘There appears to be no doubt that thev contained
silicates and carbon dioxide in solution, and other substances may
have been present. Silica liberated from the lavas as a result of
pneumatolytic alteration may also have contributed to the-same
result.

Discusston.

The PrestpEnt (Dr. A. HarKER) welcomed this contribution to
the petrology of the Carboniferous lavas. The interesting alkaline
types described had been hitherto neglected, owing partly to a ten-
dency to select for study the fresher looking material. It would
appear that in Lower Carboniferous times the British area included
two petrographical provinces, both characterized by rock-types rich
in sodic felspars, but having different histories. The southern or
Cornish province was an old-established one, and was spilitic: the
Somerset lavas must be included here. The northern province
represented a reaction from the very different Caledonian régime,
and was marked by the prominence of olivine-basalts and muge-
arites, with some soda-trachytes: here belong the Scottish and
Irish districts with the Isle of Man. In Derbyshire, occupying
geographically an intermediate situation, the voleanic rocks seem
to be mainly of Scottish types, but with spilitic affinities indicated
in some of the occurrences.

Mr. E. B. Batiey queried the application of the term ‘spilitic ’
to a suite of rocks in which pseudomorphs after olivine are com-
monly found. He thought that the decomposed lavas of Derby-
shire might be compared perhaps with albitized basalts and
mugearites from the Scottish Carboniferous, rather than with
the numerous occurrences of spilites described by Dr. Flett from

24 LOWER CARBONIFEROUS (vol. lxxiu,

other formations. The problem of albitization had attracted con-
siderable attention from British geologists since Mr. Grabham
noticed albitization among the Scottish Carboniferous lavas: A
notable recent contribution was that of Mr. MeLintock, who had
studied the Tertiary propylites—to use the late Prof. Judd’s
nomenclature—of the island of Mull. It was best to discuss the
origin of albitization in every case upon the local evidence. In
connexion with the present paper, which added considerably to our
knowledge of the Derbyshire volcanic rocks, it was important to
know whether the accompanying analyses could be fully relied
upon.

a he. A. H. Cox wished to congratulate the Author on the results
of the investigations. He had been particularly interested in
hearing these results, sinice they confirmed opinions at which he had
previously arrived from theoretical considerations. The President
had already referred to the Derbyshire rocks as being intermediate
in character between the Lower Carboniferous lavas of Devon
and Cornwall on the one side, and those of Scotland on the other.
The stratigraphical conditions were also intermediate. The lavas
of the West of England were extruded in an area which, having
undergone prolonged subsidence, was geosynclinal in character,
and the rocks were typically spilitic. On the other hand, the
Lower Carboniferous of Scotland was a shallow-water formation,
implying only a limited amount of subsidence, and the lavas were
typically basaltic, sometimes, it was true, showing a certain amount
of albitization. Opposed to this was the Lower Carboniferous of
Derbyshire—a massive limestone formation, evidently deposited in
deeper water, implying a greater degree of subsidence, though not by
any means to such a degree as that which had obtained in the West
of England. It was to be expected, therefore, that the Derbyshire
lavas, while very largely basaltic, would yet show a closer approach
to the spilitic type than was manifest in the case of the Scottish
rocks. The whole question of a possible connexion between the
type of earth-movement and the composition of the igneous rocks
produced during such movement was still an open one, and papers
such as the Author’s were most valuable as furnishing the data by
means of which this important subject could be investigated.

The AutTHoR, in a brief reply, desired in the first place to thank
the President and Fellows for their kind reception of his paper.

In regard to Mr. Bailey’s view that it was misleading to call an
olivine- bearing rock a spilite, he pointed out that, since the spilites
appear to be derived from the basalts, and since there are both
olivine-basalts and basalts without olivine, there seemed to be no
valid reason why there should not also be olivine-spilites and
spilites without olivine.

It had been a question of some difficulty whether the Derbyshire
rocks should be placed with the spilites or with the mugearites :
he thought, however, that, in view not only of their structure but
also of their physical environment, they came nearer the former

part 1] SPILITES IN DERBYSHIRE. 25

than the latter. The Carboniferous Limestone was no doubt
a deeper-water formation than the Calciferous Sandstone; and
the conditions obtaining in Derbyshire, when the spilites of that
area were erupted, probably more nearly approached those of
Cornwall at the same period than those of the Lothians. He
deprecated unnecessary additions to the nomenclature of rocks, and
thought that, if the term potash-spilites were used for the
Derbyshire rocks, their outstanding peculiarity would be sufficiently
indicated.

With regard to the analyses, he quite agreed as to their import-
ance, and had every confidence in their accuracy.

In reply to Dr. Cox, he agreed that, although no active folding
or faulting took place when the Derbyshire rocks were erupted,
there was clearly a state of slow and prolonged subsidence, although
not to the same extent as in Cornwall, and this might have been
a factor in the evolution of the rocks.

¢

26 PROF. H. H. SWINNERTON AND MR. A. E. TRUEMAN [ vol. xxiii,

3. The Morpnotoey and DEVELOPMENT of the AMMONITE
Septum. By Henry Hurp Swinnerton, D.8e., F-GS.,
Professor of Geology & Geography in University College,
Nottingham, and ArtHur Enisan Trueman, M.Sc. (Read
April 18th, 1917.)

[Puates II-IV.]

CONTENTS.
Page

I. Introduction 22... 5.005 se og se hos nes bales 14)
I. Methods of Investaation .......4:5..:)..../2..-0s500) 27
TET. Materials used:in the Investigation ............:......:. ..ae 31
IV. The Morphology of the Adult Septum ........................ 31
¥. Ferminology' of Lobes and Saddles ......../-.....:y-5- oe 34
Vi. The Formation of the Septum ......00.....:.. 52 See 35

VII. The Development of the Septum of Dactylioceras commune. 36

VIII. The Adult Suture.of the Dactyloidsz ........................... 38
IX. The Adult Suture of Dactylioceras commune.................. 40

X. Development of the Suture in Dactylioceras .................. 40

XT. Septal Sections of Dactylioceras |... .:....:....... 4 beeen 41
XII. Septal Sections of Tragophylloceras loscombi.................. 45
XIII. Septal Sections of Spheroceras brongniarti .................. 47

* XIV. The General Consideration of Septal Sections ............... 49
XV. Asymmetry in Suture-Lines’........ 0.2... 5.5. ces seas ee 51

I. IyrrRopwcrion.

SEVERAL years ago one of us noted with particular interest the
appearance of the sutures upon some badly-weathered ammonites.
They were characterized by an absence of frilling and a simplicity
of curvature strongly suggestive of the early stages in development.
A preliminary enquiry was immediately made into the development
of the sutures of Dactylioceras, and into the changes produced in
the adult suture by filing the surface away in imitation of the
process of weathering. This made it evident that the similarity
already noted was not merely superficial, but had a widely-extended
significance. It was with the view of establishing the extent and
limitations of this similarity, as determined by variations in the
shape of the whorl in different ammonites, that the present
investigation was undertaken.

As the work advanced, the problem resolved itself into a study
of the morphology and development of the septum as opposed to
the suture-line. ‘The value of the latter has long been recognized,
and a distinguished succession of workers, including Sowerby,
Hyatt, Neumayr, and Buckman, have made very effective use of it
in solving problems of ammonite affinities. On the other hand,
and apart from the suture-line, the septum itself has been com-
paratively neglected, and much of the information which exists
concerning it must be gleaned from figures, frequently undiscussed.

lal

partl] oN THE MORPHOLOGY OF THE AMMONITE SEPTUM. 27

There has also been a limited discussion upon the mechanical
conditions which have been concerned in modelling the septum,
and upon the relatiéns of newly-formed septa to their predecessors.

Il. Merruons oF INVESTIGATION.

The chief obstacle to the study of the septum is the difficulty
experienced in isolating the casts of successive chambers in such a
way as to show a septal face with all its marginal frilling complete.
This difficulty increases as the frilling becomes more complex.
It is very seldom that a specimen breaks naturally in such a way
as to show a complete septum, for the minor, if not the major,
frills are almost invariably broken. ee

The septa shown in Pl. ITI, figs. 1, 6, & 7, were cleaned with
acid and tools, and supplied much useful information. The
alternative method was to file away the superficial portions of a
whorl in successive layers. This brought to view a series of sec-
tions of the septa cut approximately parallel to the periphery.
Such sections are hereinafter referred to as septal sections.

To secure accuracy in working, much use was made ‘of the
instrument figured in PI. IT, fig. 1, and shown in the accompanying
text-figures (1 & 2, pp. 28-29) in plan and elevation.

This was designed with the expert assistance of Dr. P. EH. Shaw,
of the Physics Department of University College, Nottingham.
{t consisted of two parts. The one was a microscope with micro-
meter eyepiece and graduated rack-scale, of the kind commonly
used in physical laboratories.. The other consisted of a graduated
turn-table (fig. 2a) mounted on another table (6) which could
travel horizontally. This latter had one edge provided with a
vernier and laid against a fixed horizontal scale. Above the table
was a double-pointed needle (c) held up in the position of rest
shown in Pl. II, fig. 1, by a lever (d) actuated by a spring (e).
The needle passed loosely through the lever, and rested on it by
means of a collar (f). When the lever was pressed down the
needle was left free to fall. As it was very light, a spring (7) was
inserted which, by pressure on a collar (h) near the lower end,
ensured a certain but gentle contact of the point with the surface
of ‘the table, or of the object of study. When the lever was
released, the needle was at once lifted by it to the position of rest.
The microscope was focussed upon the upper point of the needle,
and its precise position, as recorded in the micrometer eyepiece
and on the rack-scale, was noted. The amount of drop of the
needle on to the table, or on to different points of the surface of
an object, could then be easily registered—for small movements by
means of the eyepiece alone ; for large ones, by the rack-scale.

In obtaining the measurements for producing the contoured
plan of a septum (fig. 4, p. 82) the specimen was securely fastened,
with the septal face upwards, on the centre of the turn-table. This
being caused to travel horizontally, a series of heights, or depths,
was taken at definite intervals along one diameter of the septum.

oar
=
==: tie [OALIZ [eyUOZTIOY
— 1OFJ MAINS popeoiyy our
=——

ees

ee

=
11M
eB

‘spuoym puv njpdas fo saanfuns ayy hurjaaa, pun hurkaawns ur pasn puaunspsur ayy JO UngT— | ‘Siy

Fig. 2.—Section of the instrument used in surveying and
levelling the surfaces of septa and whorls.

ferelayce
) 2s sss
i,
A
lz
AY
Al i
A IA
AY
A:
Zi
Zi
A
%

; =
ol SSS SOS

Za
RSS

TET:

UZ NLL

ACNE SSN

Section at a-a.

30 PROF. H. H. SWINNERTON AND MR. A. E. TRUEMAN [vol. lxxiii,

The table was then rotated through a certain number of degrees,
and another diameter was brought into line with the direction of
travel. This process was repeated until readings had been taken
along a sufficient number of radial lines to allow of a contoured
plan being made. Though this plan proved of great value, it
could not be relied upon to record certain details, inasmuch as any
portion of the septal surface which tended to be an ‘under-cut’
could not be registered by the vertically moving needle.

In the preparation of a plan (figs. 11, 14, & 17, pp. 44, 46, & 49)
showing the precise position of successive surtaces produced by filing,
the following procedure was adopted. A portion of an adult whorl,
containing at least one septum, was isolated, and the ends were
ground flat and polished along a plane parallel to that of the septum.
The specimen was then placed on the turn-table, with one of its ends
pressed against the polished side of a metal block, fastened so that
the plane of the septum lay in the direction of travel, and under
the point of the needle. The rounded venter of the whorl was then
made to pass under the needle, and readings were taken at regular
intervals by means of the scale and vernier. This was repeated
for the side and the dorsum. The surface of the whorl was then
carefully filed away over the area occupied by the suture-line.
Within the zone of complicated frilling, in a specimen of the size
of Dactylioceras commune, a depth of only -25 mm. was removed ;
but in deeper and less complicated regions of the septum this was
increased to ‘5 mm. or even more. At each level a series of read-
ings was taken, and the corresponding profile of the filed surface
was made and introduced into the plan. With small ammonites
the whole specimen was used, and a wax or plaster mould was
made to hold it.

For the purposes of general systematic work, upon a large
quantity of material, the methods just described involve too much
labour and, incidentally, the whole of the septum may be lost by
filing. Such methods were necessary in order to test the value of
septal sections of one septum for the first time, and all the results
recorded in the following pages were obtained by them. For most
purposes, it will suffice if the worker takes a portion of a whorl
containing not less than eight septa, and files it into a truncated
cone or, better still, into a series of steps (Pl. II, figs. 3 & 4).
The successive septa will be cut at increasing depths, and will
show most of the salient features seen in a series of sections made
from one septum. As a rule, the differences between successive
septa will not be great enough to vitiate the results seriously
(compare Pl. II, fig. 4 with text-fig. 10, p. 43), and at the same
time the series can be preserved for reference.

The camera lucida was used for drawing the sutures and septal
sections of small fossils. The whorl was turned to show successive
portions the drawings of which were subsequently pieced together.
Sutures of larger specimens were reproduced in the manner
suggested by Mr. §.S. Buckman:1 namely, by painting the chamber
behind the suture and then tracing the latter.

1 <Tnf. Ool. Amm.’ Monogr. Paleont. Soc. 1894, p. 380.

part 1] ON THE MORPHOLOGY OF THE AMMONITE SEPTUM. dl

III. MarerraLs USED IN THE INVESTIGATION.

Three species of ammonites were chosen for the main part of
this enquiry, namely :—

Dactylioceras commune, because it had what may be defined as a
normally shaped whorl: that is, neither depressed nor compressed
to-any marked degree.

Sphexroceras brongniarti, as an example of a form possessing a depressed
whorl.

Tragophylloceras loscombi, as representing forms possessing elevated and
compressed whorls.

In the two former the development of the suture was worked
out in the same specimens as those from which the septa used for
making septal sections were taken. In the first, a series of septa
was also cleaned, while the protoconch and first whorl were re-
constructed in wax, and arranged in such a way that the separate
chambers could be taken apart and the septa examined.

Fig. 3.— Graph showing the average profile of the adult septum
of Dactyloceras commune (see Pl. LIT, fig. 1).

mms.

° Sees ee Deerneaene

aay

—2L.

Area of anterior folds
Flattened area
Area of posterior

Area in front of successive contours.

We are indebted to Mr. W. D. Lang, F.G:S., of the British
Museum (Natural History), for samples of the third, and we relied
for the sutural development upon the figures of Mr. L. Spath,!
which we reproduce here in fig. 12 (p. 46). The details of other
material will be given below.

IV. THe Morpnoroey or tHE ADULT SEPTUM.

The consideration of the morphology of the septum may be
approached from a study of the contoured plan (fig. 4), which was
made from a cleaned septum of an adult Dactylioceras commune.

1¢On the Development of Tragophylloceras loscombi’ Q. J. G. S. vol. Ixx
(1914) p. 341.

32 PROF. H. H. SWINNERTON AND MR. A. E. TRUEMAN [ vol. lxxiu,

The septum was 14 mm. broad, and measured 9°25 mm. from
dorsum to venter. The datum-plane taken passed through the
centre of the ammonite at right angles to the plane of coiling,
and touched the septum tangentially in its median line.

The general form assumed by septa has been aptly described by
S. P. Woodward ! as

. nearly flat in the middle and folded round the edge like a shirt-frill, where
they abut against the outer shell-wall.’

The anterior folds are referred to as saddles and the posterior -

as lobes. The extreme antero-
Fig. 4.—Contowred plan of the posterior range from crest of sad-

adult septum of Dactylio- dle to trough of lobe was 6°5 mm.

ceras commune (see P/. III. The graph shownin fig. 3 (p.31)

ig DB) was made by finding the relative
areas of septum in front of succes-
sive contour-lines. It shows that
nearly 52 per cent. of the area of
the septum les between contours
only 0-75 mm. apart. This
portion of the septum, with its
extensions into the folded region,
is shown with dotted shading in
fig. 4. This flattened area is con-
centrated chiefly in the centre of
the septum, and coincides approx-
imately with the datum-plane.
The central area is crossed by
very slight undulations, which
unite the corresponding folds of
the opposite sides, or of the venter
and dorsum, in all three genera.
In highly compressed or depressed
ammonites these undulations be-
come more or less strongly de-
veloped folds.

From the graph it is also
apparent that the area occupied
[The shaded portion is the flattened by the posterior folds is much

area ; the thick lines represent oyeater than that occupied by the

the posterior folds, or lobes: anterior folds, and further that the

the thin lines represent the i niente : +6 thane
anterior folds, or saddles. The ~OTMer ate MON set
contours are drawn atintervals latter. It thus appears that the

of 0°25 mm.] septum as a whole is convex for-
wards, as stated by J.-F. Blake ?;

although it should be noted that sections across the septum in

1 * Manual of Paleontology ’ 1872, p. 286.
* «The Yorkshire Lias’ 1876, p. 263.

part 1] ON THE MORPHOLOGY OF THE AMMONITE SEPTUM. 33

different directions are here convex there concave. Branco?! and
Hyatt? both observe that in median sections of ammonites the
profile of the septum, passing as it does along the troughs of the
dorsal and ventral lobes, necessarily appears convex forward. On
the other hand, it may be remarked that profile sections along the
crests of individual saddles are concave forwards. Thus the form
of an anterior fold of the septum is comparable with that of a
horse’s saddle, or with the heteroccelous articular surface of a bird’s
cervical vertebra, since sections along the crest, and at right angles
to it, are concave, and convex respectively.

Norr.—J. F. Blake suggested that the forward convexity of the septum
is evidence of pressure from behind the animal, and that the saddles represent
parts of the edge which have yielded to the pressure. In more recent work
Pfaff * also concludes that the form of the septum has been determined largely
by pressure upon the posterior part of the animal. Probably, as in the Pearly
Nautilus (Willey*), the chambers of the shell were filled with gas secreted by
the veins of the mantle. In ammonites the vigour of secretion may have
been so great that the gas exerted sufficient pressure upon the soft mantle to
make it bulge forward, while the septum was being deposited. The forma-
tion of a new septum must always have been preceded by a period of rapid
evolution of gas. Perhaps the pressure thus produced helped the forward
shifting of the posterior end of the long worm-like body of the ammonite.

In all three types of ammonites considered, the axes of the folds
are always approximately at right angles to the whorl-surface
(Pl. IIT), and they maintain this relation throughout all the changes
in shape of the whorl which take place during development or
during the distortions associated with asymmetry (Pl. IV, figs. 1
4, & 9).

Hach pair,of folds behaves independently of the others. Thus,
in the development of the septum of Dactylioceras commune the
axis of the internal saddle is at one stage almost continuous with
that of the external saddle (Pl. III, fig. 3); but as, during
development, the whorl increases in height, it comes into a similar
relation with the first lateral saddle (Pl. III, figs. 1&2). The

same independence is manifested also in the development of the
septum in Tragophylloceras.°

This independence finds further expression in the variations of
arrangement of the folds according to the shape of the whorl.
When this is round, as, for example, in Lytoceras, they radiate
from a central point; when it is impressed dorsally, as, for instance,
in Dactylioceras and Spheroceras (Pl. III, figs. 1 & 7), the
internal folds come into relation with the corresponding external
saddles, and the number of dorsal and ventral elements is nearly
equal; when it is compressed, as in Tragophylloceras (PI. Ey,

1 ¢Beitrige zur Entwickelungsgeschichte der Fossilen Cephalopoden’ Palz-
ontographica, pt. 2, vol. xxvi (1879-81) p. 50.
ee Genesis of the Arietide’ Smithson. Contrib. to Knowledge, No. 673,

3 * Form & Bau der Ammonitensepten & ihre Beziehungen zur Suturlinie’
Jahresb. des Niedersichs. Geol. Verein, vol. iv (1911) p. 208.

+ * Contribution to the Natural History of the Pearly Nautilus’ Zool.
Results .... New Britain, New Guinea, &c., pt. vi, 1902, 4to. Cambridge.

° L. F. Spath, Q. J.G. 8S. vol. lxx (1914) pl. xlix.

Q. J. G.S. No. 289. psy

b)

34 PROF. H.H. SWINNERTON AND MR. A. E. TRUEMAN [ vol. lxxin,

fig. 6), the ventrally situated folds of the external series come into
line with their fellows of the opposite sides, and consequently
the elements of the venter exceed those of the dorsum by the
number of folds which thus cross the central area.}

VY. TERMINOLOGY OF LOBES AND SADDLES.

Some of the existing terminologies for lobes and saddles of the

suture-line cannot be adopted for the present purpose, because they
are to a great extent arbitrary. Thus the term superior, as
applied to the first two lateral saddles, although it fits in with
the accepted conventional method—used even in our own figures—
of representing the septum, is quite wrong when the septum is cor-
rectly placed with its venter downwards, in the attitude which
it is believed to have assumed when the animal was alive.
- The terminology suggested by Mr. 8. S. Buckman? is most
nearly in accordance with the facts of development, and will be
adopted here. He gives the name of external saddles to the
pair on each side of the ventral lobe; and uses the term lateral
for the others. The difference thus implied is a real one: the
external saddles originate from the large median saddle (‘ aussen-
sattel’ of Branco) of the first septum by the appearance upon its
crest of a median lobe (Spath, op. ezt. 1914, p. 341; A. E. True-
man®). The lateral saddles, on the contrary, appear as simple folds
on the umbilical angle, and travel thence towards the venter
(PL IIL; and Spath, op. ezt. pl. xlix, figs. 2a & 26).

The development of the folds on the dorsum apparently follows
the same lines as those just laid down for the venter. - Thus, the
first septum shows occasionally a median saddle (fig. 12 a, p. 46;
Spath, op. e7t. pl. xlviui, fig. 2¢). In the second septum this has
given place to a median dorsal lobe flanked by the internal saddles.
The remaining elements appear at the umbilical angle, and travel

towards the median dorsal line (see figs. 9 ¢, d, & e, p. 42; 12¢&

e, p. 46; and lic, d, f, & g, p. 48).

Although the distinction into laterals and auxilaries may be
convenient for descriptive purposes, it does not correspond to any
morphological difference between the folds—inasmuch as_ the
auxiliaries also appear for the first time as simple folds on the
umbilical wing of the septum, and travel towards the venter or
towards the dorsum, as the case may be. Moreover, the auxiliaries
of one ammonite may correspond to the laterals of another.
Thus, development shows that the large second lateral of Trago-
phylloceras loscombi is the strict homologue of the small first
auxiliary of Dactylioceras.

! The septal aponeurosis of ammonites does not seem to have been so well
developed as in Nautilus. In them the fibres were apparently isolated and
attached to the shell along a wavy line at points indicated on the suture-line
by denticles. Pressure upon a membrane thus attached by its margin must
produce folds at right angles to the periphery.

2 ‘Yorkshire Type Ammonites’ vol. i (1909-12) p. ix.

3 «The Lineage of Tragophylloceras loscombi’ The Naturalist, 1916, p. 222.

part 1] ON THE MORPHOLOGY OF THE AMMONITE SEPTUM. 35—

VIL. THe FoRMATION OF THE SEPTUM.

Evidence bearing upon the mode of deposition of the septum is
scanty. In an adult specimen of Dactylioceras commune from
Grantham, the last septum was found to be only in part secreted.
Its suture was clearly visible as a white line at the umbilical angles.
Here the secretion of the septum was evidently well-advanced, but °
elsewhere it could be seen only as a faint dark line—possibly due to
a conchiolin membrane. Septal sections seemed to indicate that
the septum was incomplete internally; but a definite statement
cannot be made, for it had evidently been disrupted when the shell
was becoming filled with mud. The evidence shows that the

Fig. 5.—Last two suture-lines of two ammonites showing the
last suture incompletely formed.

b

tf

io
z

a=Dactylioceras commune, Grantham. Diameter=57 mm.
b=Polymorphites jupiter, Old Dalby. Diameter=18 mm.

secretion commenced in the region farthest removed from the
siphuncle. Partly formed septa, showing the same peculiarities,
have also been noticed in Polymorphites jupiter d Orbigny (fig. 56).

The formation of the septum in ammonites seems to have taken
place in the same manner as in living Nawtelus. It has long
been known! that in the latter the deposition of calcareous
matter begins at the sides of the shell, and proceeds towards the
siphuncle. Willey (1902) observed further that the secretion of a
septum was preceded by the formation of a conchiolin membrane,
upon which the calcareous matter was deposited.

The septa, just described for Dactylioceras and Polymorphites,

1 F, A. Bather, ‘Growth of Cephalopod Shells’ Geol. Mag. dec. 3, vol. iv
1887) p. 447.
D2

36 PROF. H. H. SWINNERTON AND MR. A. E. TRUEMAN [ vol. lxxil,

were complete in all sutural details and, though only formed
in part, were situated at the normal distance from the preceding
septa. These facts run counter to, the views of Riefstahl !
supported by Buckman?; and, along with the observations of
Willey (1902) upon Nautilus, they furnish further support, if
such be needed, for those of Bather? and Appelléf.4 According to
Riefstahl, the last septum was formed in contact with the previous
one, and became separated by the growth of the intervening
shell-wall. He based his view upon the microscopical study
of the sepion. This, however, is so highly modified that it would
not be safe to use it for throwing light upon the formation of the
septum of the (comparatively) closely-allied belemnite, still less
upon that of the only very distantly-related ammonite.

VII. Tur DEVELOPMENT OF THE SEPTUM OF
DACTYLIOCERAS COMMUNE.
(1) The Second Septum.

A wax model enlargement was made of the second septum, and
from this a contoured plan (fig. 6) and a graph (fig. 7), like those

Fig. 6.—Contoured plan of the second septum of Dactyloceras
commune shown in Pl. III, fig. 4.

| Explanation as in fig. 4 (p. 32). The contours are drawn at intervals
of 0°01 mm. }

already described for the adult septum, were constructed. The

1 «Die Sepienschale & ihre Beziehung zu den Belemniten ’ Palzeontographica,
vol. xxxii (1886) p. 20.

2 «Notes on Nautili & Belemnites ’ Proc. Geol. Soe. vol. xlvii (1891) p. 165.

% * Shell-Growth in Cephalopoda’ Ann. Mag. Nat. Hist. ser. 6, vol. i (1888)
p. 298.

4 * Die Schalen von Sepia. Spirula, & Nautilus’ Kong]. Svenska Vetenskaps-
Akad, Handl. vol. xxv, No. 7 (1893) p. 28.

part 1] ON THE MORPHOLOGY OF THE AMMONITE SEPTUM. 37

septum itself was 0°95 mm. broad, and 0°22 mm. from dorsum to
venter. The extreme antero-posterior range from the crest of the
saddles to the trough of the lobes was 0:16 mm. The area shaded
in the plan is comparable with the flattened area of the adult, but
is relatively much less extensive. It hes between contours 0°03 mim.
apart, and occupies 30 per cent. of the area of the septum. On the
whole, the septum tends to be concave rather than convex forwards.

It is evident that the septum-secreting portion of the mantle,
which-was strongly convex at the time of formation of the proto-
conch and even of the first septum, had already,begun to feel the
influence of that pressure, which in later life became strong
enough to impose upon it a marked concavity. In the more
primitive ammonoids, especially the Asellati,! the form of the
earlier septa proves that this influence did not develop quite so
rapidly in them as it did in the specialized forms represented by
Dactylioceras.

%

(2) Comparison of the Second with the Adult Septum.

On comparing the second septum of Dactylioceras (Pl. III) with
the adult septum, it is seen that, apart from the peripheral zone, the
latter shows all the essential features of the former, so that, except
for the increase in size and flattening of the elements,the major
portion of the septum has undergone no significant change during

development. The
Fig. 7.—Graph illustrating the average changes already
profile of the second septum of Dacty- mentioned above :
hoceras shown in Pl. III, fig. 4. namely, the relative
ae movements of the
first lateral saddle
as the height of the
whorl increases, and
the origin: of the
new lobes and sad-
Wey T ot Dataenine dles on the umbilical
wing of the septum,
are confined to the
marginal area.

It must not be

Area in front of successive contours. supposed, however,

that this general

agreement of the major portion of the adult septum with the whole
of the second septum is due merely to a simple enlargement of the
area which secreted the latter. Had this been the case, the siphuncle
would have retained the subcentral position of the second septum
throughout life. During the growth of the first and second whorls,
however, it gradually shifts to the ventral margin, and thus comes
to lie within the frilled peripheral zone. In some cases, according

704

—*04

Area of anterior

Flattened |
Area

' W. Branco, Paleontographica, vol. xxvii (1880) p. 68.

38 PROF. H. H. SWINNERTON AND MR. A, E. TRUEMAN [ vol. lxxiu,

to Branco,! the siphon hes near the internal margin of the early
ee as in most latisellate ammonoids; while in certain forms,

, for example, Goniatites lamed var. calculiformis, it occupies
a Bertha position from the first. Despite these variations in
position of the siphuncle, the development of the septum pursues a
definite course. Assuming that there is noactual migration of the
siphuncular cord through the substance of the mantle, it may be
taken as furnishing a datum-point. It then seems as though a
portion of the mantle ventral to this point is withdrawn from
taking part in the secretion of the septum, and that the mantle
dorsal to it increases, especially on the umbilical wings. Through-
out development, and also despite all the distortions associated
with asymmetry (Pl. IV), the siphuncular cord and ventral lobe
remain intimately related.

The close similarity in form between the early septum and
the central part of the adult septum suggests that the study of
the latter may give some clue to the development. In actual
practice the contouring of a cleaned septum was found to be un-
satisfactory for this purpose, inasmuch as the instrument could not
be made to deal efficiently with undereut or even vertical portions
of the surface. On the other hand, septal sections proved highly
satisfactory. Before considering these, it will be necessary to
provide a’ basis for comparison by giving an account of the suture-
line of Dactylioceras and of its development.

VIII. Tue Aputt SuTruRE oF THE DacTYLOIDE. *

Betore proceeding to the detailed description of the adult suture
in the specimen from which both developmental details and septal
sections were obtained, it will be helpful to refer briefly to the
general features of the suture-lines in the family Dactyloide and
in the Cceloceran forms from which it has been derived. Unfor-
tunately, the material at our disposal was neither abundant enough
nor sutticiently complete to permit the elucidation of major and
minor lines of descent within these families. Nevertheless, there
was sufficient to lead to the detection of certain tendencies which
throw much hght upon the problem now being considered.

The material examined included the following species :—

Dactylwoceras commune (Sowerby). | Peronoceras fibulatum (J. de C. Sowerby).

D. crassum (Young & Bird). Porpoceras andrei (Simpson).
D. annulatwm (Sowerby). Celoceras pettos (Quenstedt).
D. turriculatum (Simpson). C. fonticulus (Simpson).

The general relationships of some of the variations of the
suture-lines within this family may be illustrated from one
specimen of Dactylioceras by a comparison of its last suture with
that of a slightly earlier one, namely, the tenth from the last
(fig. 8, u & i).

During the interval between the deposition of these two septa

1 Op. cit. p. 62.

part 1] oN THE MORPHOLOGY OF THE AMMONITE SEPTUM. 39

some change—which, following the prevailing custom, may be
ascribed to the onset of senile decay—had taken place in the
animal. This expressed itself in the suture-line by a considerable
decrease in the antero-posterior range of the lobes and saddles,
accompanied by a swinging forward of the umbilical portion of the

suture-line. These
Fig. 8.—Suture-line of Dactylioceras ~ changes, which lead
and Cceloceras. to a crumbling-down

of the apices of the
saddles to approxi-
mately the same plane,
strongly suggest a
diminution in the
forward convexity of
the septum. Mean-
while the — saddles
broadened out, and
the demarcation from
the lobes became more
ill-defined. In minor
details the later sep-
tum seems at first more
intricately wrinkled, a
feature which is still
better exhibited in
other specimens (fig.
8,1), some of which
show these and other
‘ageing’ characters
through a wide range
of septa. This com-
plexity is strongly
suggestive of the
wrinkling of a collaps-
[1-3= Dactylioceras commune ; 2, at the diameter ing or flaccid bladder,

of 45 mm.; 3, at the diameter of 39 mm.10 as opposed to the

sutures earlier in the same specimen. 4= simpler and more tur-

Celoceras fonticulus from Whitby ; diameter, . cies Ss
28 mm. 5=Celoceras pettos from Baden ; gid outlines of th 2
folioles in — earlier

diameter, 27 mm. |
septa, and suggests a
a ee in the vigour of gas-secretion in the declining period
of life.

The features that distinguish the earlier septum become more
obvious in the primitive members of the family, and lead by an
almost perfect gradation of changes to the condition observed in
Celoceras pettos (fig. 8, v).

The Dactyliocerates are evidently a decadent offshoot of
Celoceras.1. In them are to be seen the phenomena which

1 §. S. Buckman, ‘On the Grouping of some Divisions of so-called “ Jurassic”
Time’ Q. J.G.5S. vol. liv (1898) p. 442.

40 = PROF. H. H. SWINNERTON AND MR. A. E. TRUEMAN | vol. lxxii,

characterize the first stages in the simplification of the suture-line,
a simplification that is carried to such extremes in Cretaceous
ammonites.

IX. THe ApULT SUTURE OF DACTYLIOCERAS COMMUNE.

The adult suture (fig. 97, fig. LO m) shows externally a deep
ventral lobe divided by a median saddle, and flanked by broad external
saddles. The first lateral lobes are almost as wide, but not so deep,
as the ventral lobes; while the first lateral saddles are of smaller
proportions than the external saddles, presenting in this respect a
marked contrast with Tragophylloceras. The second lateral lobes
are very small, and the two auxiliary saddles of the external series
are insignificant. Internally, the dorsal lobe with its minute
median saddle is the most important feature, being exceeded in
depth only by the corresponding lobe of the external series. A
pair of internal saddles, about as high but slightly narrower than
the first lateral saddles, and a pair of smaller auxiliaries separated
from the internal saddles by internal lobes, are also present. Al]
the features of the suture-line, except the auxiliaries, are compli-
cated by the presence of frillings or denticulations. On each of
the external saddles are three main divisions similar to the sumple
divisions on the internal saddles. The first lateral lobe of the left
is markedly trifid. That of the right side is abnormal. A similar
asymmetry has been noticed in other ammonites, as, for example,
in Sonninia.2 While these major frillings are symmetrically
developed on each side of the median line, the minor frillings are
less constant, and frequently give rise to asymmetry. Thus,
although the three minor frillings on the central division of the
external saddle are present on each side, the small frills on the dorsal
foliole of the same saddle are much more developed on the left
than on the right side. It appears, therefore, that, at least in
such retrogressive types as Dactylioceras, only the major frillings
can be of systematic importance. The minor frillings, which
further complicate the suture, show even on opposite sides of the
saine suture an inconstancy that may be associated with the
phenomena of decline discussed above.

X. DEVELOPMENT OF THE SUTURE IN DACTYLIOCERAS.

The first suture (fig. 9a, p. 42) of Dactylioceras shows the
usual angustisellate condition.

In the second suture (9 4) a well-defined ventral lobe is present,
which is as broad as it is deep. The dorsal lobe is similar, but
smaller; both are deeper than the lateral lobes. As in the adult
suture, the external saddles are the largest, and the internal saddles
come next in size. The first lateral saddle is just appearing as a
low fold close to the umbilical angle.

Right and left as used in the description refer only to the figures.
* S.S. Buckman, ‘ Inf, Ool. Ammonites’ Monogr. Palxont. Soc. 1894, p. 381.

part 1) ON THE MORPHOLOGY OF THE AMMONITE SEPTUM. 44

In the seventh suture (9c) the same proportions are maintained.
The new features to be noticed are the appearance of a median
ventral saddle, the increase in size of the lateral saddle, and the
presence of another saddle, the internal auxiliary, near the um-
bilical angle.

The folds just described persist throughout the remainder of the
first three whorls, with little change in “their relative proportions.
Meanwhile crimping begins, and the first external auxiliary appears
near the umbilical angle (9 e). The external saddle becomes tri-
lobed, and thus resembles the internal saddle of the adult. The
first lateral lobe on the left is trifid, while that of the right is only
bifid; thus, even at this early stage, the curious asymmetr Vv already
noted in the adult has become established.

In the fourth whorl (9,f) frilling becomes still more marked.

In the fifth whorl (9 7) crimping is carried farther, but its small
taxonomic value is made evident by a comparison of the right
and left sides. The left lateral lobe is wide, and has the primitive
ae appearance of the corresponding lobe in Celoceras
(fig. 8, iv & v, p. 39). Up to this stage the outlines are all
manifestly turgid.

In the sixth whorl (fig. 9h, p. 42) conditions giving rise to flaccid
outlines have begun to set in.

The development of the dorsal series of lobes and saddles pro-
ceeds along similar lines to that of the ventral series, but the
details are later in appearing. For example, no signs of frilling
are present on the lobes and saddles of the dorsum at the fourth
whorl (9), yet marked frilling was already manifest in the
ventral series before the end of the third whorl (9¢). Again, the
median saddle of the dorsum does not appear until the fifth whorl,
and it always remains small; but the corresponding saddle of the
ventral series is present three whorls earlier. Further illustrations
of the same principle are afforded by the development of Trago-
phylloceras and Spheroceras. Branco noted a similar feature in
many other enone. The conditions in Clymenia (Paleonto-
graphica, pt. 2, vol. xxvii, 1880, pl. vi) are exceptional, for the
dorsal folds are. more deeply divided than the ventral. The fact
that im it the siphuncle is dorsal suggests that the complexity of
folding is, in some way, associated with the position of the siphuncle.

XI. Seprat SECTIONS OF DACTYLIOCERAS.

In the foregoing pages it has been shown that the central area of
an adult septum i is strikingly similar to the earher septa. This fact
suggests that, if septal sections were made, they would show some
resemblance to the suture-lines at different stages in development.

Fig. 10 (p. 43) shows a series of such sections made at the zonal
lines shown in fig. 11. Thus section ) represents the ground edge
of the septum at zonal line 2 of fig. 11 (p, 44). This illustrates
the extraordinary flatness of the imnermost area of the septum.

Fig. 9.— Development of the suture-line of Dactylioceras
commune (figured in Pl. II, fig. 2).

| |
rg 1

Cc |
*
b T
a
a=First suture X 28. d=Suture at 13 whorlsx28. g=Suture at 42 whorls x 8,

b= Second suture X28. e=Suture at 23 whorlsx15. h=Suture at 52 whorls x 4.
c= Seventh sutureX28 f=Suture at 33 whorlsxX12. i=Suture at 63 whorls x2,

Fig. 10.—Series of septal sections made from one of the latest
septa of the Dactylioceras figured in Pl. II, fig. 2. X 2.

. |The horizontal lines indicate the position of the datum-plane. The broken
lines indicate the positions of the ribs on the original surface. The
letters correspond with the numbers of fig. 11, p. 44.]

44 PROF. H. H. SWINNERTON AND MR. A. E. TRUEMAN [vol. lxxin,

Passing outwards from this, the sections show ever more clearly
_ defined indications of folding until at section e (fig. 10, p. 43) they
are distinct enough to permit of comparison with the second suture
(9 6, p.42). Such comparison shows that, except for the flattening
of the features, all essential characters of the latter are to be seen.
If it were not for the enlargement of the first lateral saddle, the
fifth septal section (fig. 10 e) would be identical with the second
suture (fig. 96). This discrepancy is slightly rectified in the sixth
section (tig. 10/).

Fig. 11.—Section of whorl (x6) along the datum-plane of the
septum whereof sections are shown in fig. 10, p. 48.

[The lines parallel to the periphery show the positions of these sections. The
numbers 1, 2, 3, etc. correspond to the letters a, b, c, etc. in fig. 10. ]

The seventh section (109) is comparable with the seventh
suture (9¢) and those which follow it as far as the second whorl
(9d), or even a little later. This is shown by the appearance of
the internal auxiliary, and of faint indications of frilling on the
external saddles and on the first lateral lobes. It should be noticed
that at this stage, so far as main folds are concerned, the tendency
to flattening has been reversed, and the features are now relatively
deeper and narrower than in development. Section 8 (fig. 10 2) is
comparable with the sutures in the third whorl (9c), differences
being sumilar to those noticed in the previous section: that is to
say, the ermping, having just made its appearance, is (on the
whole) flatter than in the corresponding developmental stage.

part 1] ON THE MORPHOLOGY OF THE AMMONITE SEPTUM. 45

‘It is interesting to notice that the asymmetry due to the
abnormal characters of the first lateral lobe of the right side is
shown clearly in the septal sections as well as in the development
of the sutures, a fact which emphasizes the soundness of the con-
clusion; to which this comparison seems to be leading, that the
septal eeu: may be used for ascertaining some ot the leading
points in the development of the sutures.

Septal section 9 (fig. 107) is comparable with the sutures of the
fourth whorl (fig. 9/7) except that the second auxihary has made
its appearance, and that the frilling has changed in the same way as
did the major folds of the earlier sections: that is to say, they have
become deeper and narrower than in the corresponding sutures.
Their relative proportions are the same: for example, in the sutures
of the fourth whorl (9.7) the external saddles are asymmetrically
subdivided. A similar asymmetry may be detected in the ninth
section (107). The tenth section (10/:) also bears much detailed
similarity to the sutures of the fifth whorl (94): observe, for
example, the five-fingered appearance of the lett titeral lobe: By
this stage in development the animal has begun to assume adult
characters.

XII. Serpran Sections oF TRAGOPHYLLOCERAS LOSCOMBI
(J. Sowerby).

The shape of the whorl of Dactylioceras does not depart greatly
from that which is normal for ammonites. We have yet to ex-
amine to how great an extent the characteristic just observed in
Dactylioceras is true for ammonites in which the whorl has become
either compressed or depressed. As an example of a type witha
compressed whorl, Tragophylloceras loscombi is here taken. The
septal sections shown in fig. 18 (p. 46) are lettered for comparison
with the stages in the sutural development (fig. 12). The positions
of the sections in the whorl are indicated in fig. 14.

The specimen of thiS genus used by us was a young one. Its
size and last suture show that it comes in between /& and Z of
Mr. Spath’s series (op. cit. 1914, p. 340; see fig. 12). It shows
differences from his specimens, which must be borne in mind when
comparing septal sections made from it with the developmental
series given by him. For example, the great size of the terminal
leaflets of the external and first lateral saddles shown in his sutures
at # and / does not appear in the last suture of our specimen.
This fact may account for the relative smallness of those leaflets
in the septal sections. Again, Spath’s figures of sutures h and 7
do not form a continuous series with g and #: compare, for
example, the second lateral saddle and also the terminal leaflets of
the external saddles. We have been unable to detect this break in
the earlier sutures of our specimen, so that its absence in the
septal sections can hardly be accepted as evidence against their
value.

Figs, 12-14.—-Tragophylloceras loscomhi (J. Sowerby)
from Lyme Reqis.

=— £4 — £ S— © 6. oleae

;
[12 = Development of suture (from L. F. Spath, op. cit. p. 341); 13=Series of |
septal sections made from one septum, X 2; 14=Section of the whorl :
along the datum-plane of that septum, showing the positions of these |

septal sections. |

part 1] THE MORPHOLOGY OF THE AMMONITE SEPTUM. 47

As in Dactylioceras, the smaller details of the suture are so
asymmetrical about the median line as to indicate that they are of
little consequence in taxonomic discussion.. Here, again, the com-
parison of the developmental series and the septal sections may be
confined to the more outstanding features. The sections give
nothing comparable with the first suture, but the innermost
sections (fig. 13 6 & c) are almost identical with the seventh suture
(fig. 12c¢). This similarity is emphasized by the presence of the
ventral saddle which, by acceleration in development, appears earlier
in development in Zragophylloceras than in Dactylioceras: a
difference in the time of appearance which is manifested also by
the sections of the two types. As in Dactylioceras, the fresh
lobes and saddles appear at the umbilical angle in both sutures and
sections. In the sutures, the first denticnlation is shown on the
external saddle, new frillings coming in rapidly from that time
onwards. Although the relative proportions of these divisions are
not the same in the sections as in the sutures, the numbers at the
various stages are practically identical. The difference in pro-
portions may be partly explained by the difference between
Mr. Spath’s specimen and ours, as mentioned previously. It may
also be suggested that the notches which produce ‘ undercuts’ on
the folds are confined to the edge of the septum, and are therefore
necessarily shown only in the sutures, yet are absent from the
inner portions of the early as well as the latest septa. This last
fact is of practical value in breaking up an ammonite for examina-
tion: for, if the outer surface is filed away along any suture-line,
the chambers may be readily separ ated.

XIII. Sepran Sections oF SPHAROCERAS BRONGNIARTI
(J. Sowerby). (See figs. 15 & 16, p. 48.)

The septal sections of this specimen correspond very closely
with the developmental series. The order of appearance of denti-
culations in ontogeny is closely paralleled in the sections. Thus
the first frillings” in each series are developed in similar positions
on the external saddles (compare fig. 16¢ & d with fig. 15 e) after
the appearance of the median saddle in the ventral lobe. At this
stage there are three pairs of saddles in both cases. The develop-
ment of additional frillings and of small auxiliaries also proceeds
along almost identical lines. It will be noted, however, that in onto-
geny the median ventral saddle is present at an earlier stage than in
the sections: namely, before the dev elopment ot the deeorid lateral.
saddle. The differences noted in the previous comparisons are also
to be seen here; the undercuts, which are well developed in onto-
geny, are only preserved in the outer parts of the septum, and
consequently do not appear in any but the outermost sections.
Further, even in the inner septal sections, main folds are generally
more acute than in development. This is due to the absence of a
central flattened area.

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1 =}

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"SONJOUII] INU OT SHajauem¢p — -aUsoquaygy WoLf’ (hqwanoy *P) YAawpwusuoarq svtoooteydg— 9] YP EL “Sst

~

part 1] THE MORPHOLOGY OF THE AMMONITE SEPTUM, 49

Nevertheless, the similarity is sufficiently striking to justify the
opinion that the principle educed from the septa of normally-shaped
and compressed whorls holds good also, with the limitations noticed,
for forms with depressed whorls.

Fig. 17.—Section of the whorl of Spheroceras brongniarti along
the datum-plane of the septum of which septal sections are
shown in fig. 16 (p. 48). The lines parallel to the pert-
phery show the positions of these sections.

XIV. Tur GENERAL CONSIDERATION OF SEPTAL SECTIONS.

Mr. R. 'T. Jackson! has drawn attention to the phenomenon
of localized stages in development: that is to say, during life
_* stages may be found in localized parts which are similar to stages found in

the young, and the equivalents of which are to be sought in adults of ancestral
groups. ; 52

Thus, for example, the auxiliary saddles in the suture of Trago-
phylloceras are similar to the external and lateral saddles‘of the
first suture. The idea has been applied to the study of different
species in a progressive series (Lytoceras) by’ Mr. 8. S. Buckman,?
who has shown that the first lateral saddle of an early type is
at the same stage as the second lateral of a more advanced type.
The similarity of the central area of the adult septum to the
earlier septa is not, however, an illustration of the same principle.
All Jackson’s illustrations are drawn from newly developed parts,

1 «Localized Stages in Development in Plants & Animals’ Mem, Boston Soe.
Nat. Hist. vol. v (1899) p. 92. ;

2 ¢Qn certain Genera & Species of Lytoceratide’ Q. J. G. S. vol. lxi
(1905) pe Lol.

GedeG.s. No, 289. 3°

50 PROF. H. H. SWINNERTON AND MR. A. E. TRUEMAN [ vol. lxxiii,

such as the auxiliaries of suture-lines, the last-formed plates in the
stalk of a crinoid, or in the interambulacral area of an echinoid.
The simplicity of the central area of the adult septum is due to
the retention of this feature through all stages of development,
despite the increasing complexity of ‘adjoining parts.

~Just as the development summarizes the stages of evolution
with omissions here and additions there, so septal sections summarize
the development, but with omissions only. The features to be
omitted are determined by the fact that the series of changes,
shown in the passage from the centre of the septum to the edge,
represents the most direct way in which the adult septum, with
its highly complicated margin, could have been evolved from a
septum as simple as that of an asellate protoconch. I¢ this course
of evolution has been, as it were, a winding one, the winds will be
omitted, to some extent in deve elopment, and completely in the
adult septal sections.

In ammonites with normally-shaped whorls the septal sections
closely resemble the sutural development: in highly-compressed
and depressed forms, however, the central area of the septum is
like a primitive septum greatly elevated or laterally extended.
During ontogeny, the first latéral saddles in these forms early
assume adult: proportions, and consequently in septal sections the
stages represented by the earliest sutures are omitted. In no case
do septal sections show a stage comparable with the first suture.
This seems to indicate that, in ammonites, a change akin to a
metamorphosis took place in, the period between the formation of
the first and the second septum. The creature which secreted the
former was possibly larval, and followed a line of evolution of its
own: which is reflected in the series of coenogenetic changes repre-
sented by the terms asellate, latisellate, and angustisellate.
Further, in such forms as Pinacoceras, where a large number
of adventitious inflections are developed, and’ compression has
reached its maximum, we should not expect to find so close an
agreement between the septal sections and the sutural development.

With these exceptions, however, septal sections will at least
furnish a standard of direct development, 1 which may be useful for
detecting deviations in the normal development where such occur.
This direct development may or may not approach as closely as
ontogeny to a true representation of actual evolution.

Septal sections should prove especially useful where material for
the study of early stages is not accessible. Although, in ordinary
cases, sutural development may prove of greater ae than the
septal sections, where the former cannot be worked out the latter
will, to some extent, serve as a substitute.

It is well known that the sutures of senile stocks bear a close
resemblance to the young sutures of the advancing types which
preceded them. This resemblance is due, not toa “resumption of

1 We owe this suggestion to a conversation with that brilliant and much
lamented investigator, the late Dr. A. Vaughan.

part 1] oN THE MORPHOLOGY OF THE AMMONITE SEPTUM. 51

embryonic characters which have disappeared as the study of the
suture-lines alone seems to suggest, but to a bringing to the surface
once more of those embryonic features which, even in acmic
radicals, have persisted into adult life hidden from view bya narrow |
fringe of complicated frilling. During retrogression this fringe is
gradually lost, and thus a process analogous to the making. of
septal sections takes place. Strictly, the sutures of senile stocks
should be compared, not with those seen in the ontogeny of
ancestral types, but with the septal sections of the ancestral adult
septum. It is not at all unlikely that, while ontogeny summarizes
progressive evolution, septal sections forecast in similar broad out-
lines retrogressive evolution. Thus, for example, a careful study
of a large number of Bacuwlites, and a comparison with the septal
sections of ammonites from which they have probably descended,
would make it possible to connect up with certainty many of these
forms. It is to be regretted that inability to secure sufficient
material has made it impossible for us to establish this principle
satisfactorily.

XV. ASYMMETRY IN SuTURE-LINEs.

A marked tendency to asymmetry.in suture-lines has already
been noted in Dactylioceras commune. It is now proposed to
deal with this aspect of the morphology of the septum more fully.
Such asymmetry usually arises in one of two ways, namely :—

(1) By the different development of-elements of opposite sides.
(2) By association with lateral displacement of the siphuncle.

The former is of common occurrence. It has already been
described above for Dactylioceras (p. 40). It has been observed
by S. S. Buckman in Sonninia! and by Solger in Neopty-
chites.» In each of these cases the first lateral lobes of opposite
sides were different in plan. Other cases have been seen in which
this character has been associated with a tendency to helicoid
coiling, as in the ‘ Turrilites’ of dOrbigny.2 As O. Fraas has
shown,* it is only when this character has become constant, as
in Turrilites, that it is of generic importance.

Asymmetry associated with the displacement of the siphuncle
may be brought about in various ways. The most instructive
example that has come under our notice is that of a specimen
of Perisphinetes triplicatus, found in the Kimeridge Clay of
Market Rasen by Mr. F. T. Ingham. This specimen shows three
septa (Pl. IV, fig. 2); the suture of the earliest is normal, that of
the second is slightly irregular, that of the third is markedly
distorted, for the siphuncle has during this short interval become

1 «Inf. Ool. Ammonites ’ Monogr. Paleont. Soc. 1894, p. 381.

2 “Die Fossilien der Mungokreide in Kamerun & ihre Geologische Be-
deutung’ Beitr. Geol. von Kamerun (1904) p. 107.

3 *Paléontologie Francaise: Terrains Crétacés’ vol. i (1840) p. 571.

4 * Abnormitaten bei Ammoniten’ Jahreshefte Wiirttemb. xix (1863) p. 112.

52 PROF. H. H. SWINNERTON AND MR. A. E. TRUEMAN | vol. lxxiu,

considerably displaced from the median line. ‘These features of
the suture-line are only an external manifestation of an enlarge-
ment of one half of the septum (fig. 1) at the expense of the
other; in such a manner that the internal aswell as the external
lobe has been pushed to one side, and the enlarged half has also
been pushed behind the general level of the septum. That the
asymmetry is not due to an injury seems probable, since it deve-
loped slowly enough to permit of the secretion of at least two
septa. Neither does it appear to have been due to a change of
the conditions which directly affect the form of the suture, since
all the details are preserved. The cause was possibly pathological.
The facts already discussed show that the form of the septum,
even in these asymmetric examples, is independent of the internal
organs in the neighbourhood of the septum: otherwise a diseased
condition of some paired organs (for instance, the gonad) might
have been postulated. As it is, the cause must be looked for in
a diseased condition of the stretched membrane: namely, the
septum-secreting area of the mantle. If this became hypertrophied
on one side, it would still assume the form of a stretched mem-
brane, but being more resistant to pressure from behind, would not
become so concave forwards as the other half. This is precisely
the condition which the shape of the abnormal septum suggests.

Usually the change in the position of the siphuncle takes place
slowly and in one vechion only; but in a specimen of Hoplites
auritus (Pl. IV, fig. 8) it moves from side to side repeatedly, in
association with the alternate dev elopment of tubercles on opposite
sides of the venter. The mantle apparently sank into the cavities
of the tubercles, and thus caused a displacement of the adjoining
parts of the body as well as of the mantle.

Lateral displacement of the siphuncle in the example of Pev?-
sphinetes which we have just described has been accompanied by
wholesale enlargement of one half of the septum, but usually only
the ventral features of the suture are affected. Thus in the
septum of Hoplites splendens (Pl. IV, fig. 4) all the elements of
the internal series and those of the external series which are dorsal
to the first lateral lobe, are quite normal. Further, in the septum
ot Psiloceras planorbis (Pl. IV, fig. 9), the displacement is of a
character similar to that observed in * Hoplites splendens : for there
also the dorsal suture is not affected, while the elements of the
venter are disturbed even more markedly than in the latter form.

Thus the displacement of the siphuncle in Perisphinetes and
Hoplites aurvitus is different in origin from that of Pszloceras
and Hoplites splendens. Dr. J. F. Pompeckj! has, for example,
stated that the type of asymmetry in Psloceras is of systematic
Value. The discovery, also by him, of a specimen of Zragophyllo-
ceras With a similarly asymmetric suture-line, has been mentioned

' * Beitrige zu einer Revision der Ammoniten des Schwibischen Jura’ pt. i
(1894) pp. 56-71,

part 1] ON THE MORPHOLOGY OF THE AMMONITE SEPTUM. 53

by Spath (op. c7t. 1914, p. 351), presumably as corroborative evi-
‘dence of the connexions between Ps7loceras and Tragophylloceras.}
Similarly, this character has been described in Cosmoceras by
Teisseyre.2 Sayn? mentioned that he had not observed a similar
feature in Hoplites, and considered that this showed conclusively
that Hoplites was not directly descended from Cosmoceras. It
should be mentioned, however, that A. @Orbigny (1840, p. 222)
had previously noticed that asymmetry is of common occurrence
in certain species of Hoplites—an observation which we are able
to confirm.

An examination of sixteen specimens of Pstloceras planorbis
from the Lower Lias of Robin Hood’s Bay revealed asymmetry in
nine cases. Although asymmetry is of common occurrence in
Psiloceras, it would appear to be an unreliable character. Further,
Pompeckj’s figures show that the displacement varies in amount
and direction. /

The careful examination of the suture-lines of more than 600
Jurassic and Cretaceous ammonites has shown that asymmetry
due to a displacement of the siphuncle occurs sporadically in
many widely-separated genera. We have noticed it in the follow-
ing cases :-—

Psiloceras planorbis (Sowerby). *N.U.C.,N.M. Robin Hood’s Bay. 9 out
OiMliowieEl. LV, fic. 9.

‘Normaniites’ braikenridgi (Sowerby). N.M. Mesvil (Yorkshire). 1 out
Ghee vel LY, fic, 13.

Keplerites calloviensis (d’Orbigny). N.U.C., N.M. Ashton Keynes. 1
out of 3.

Aspidoceras perarmatwm (Sowerby). N.U.C.,N.M. Faringdon. 2 out
of 4.

Hoplites splendens (dOrbigny). N.U.C., N.M., B. Folkestone; Cam-
bridge. 62 out of 112.

Hoplites raulimanus (VOrbigny). N.M. Folkestone. 1 out of 2.

Dactylioceras commune (Sowerby). N.U.C., N.M., B. Whitby. etc. 10
out of 30.

Cosmoceras jason (Reinecke). N.U.C.,N.M. Woburn Sands. 5 out of 12.

The occurrence of asymmetry in so large a number of examples
of Hoplites is noteworthy, and fully bears out d’Orbigny’s observa-
tion. Yet it should be mentioned here that, in 78 specimens of
Hoplites lautus and H. tuberculatus, we were unable to detect

' Mr. Spath remarked that he had not observed any cases of asymmetry in
the specimens of Tragophylloceras loscombi from Lyme Regis. Mr. W. D.
Varney, however, has found an example of this species showing asymmetry
at Old Dalby (North Leicestershire).

* *Hin Beitrag zur Kenntniss der Cephalopoden Fauna der Ornatenthone im
Gouvernement Rjisan (Russland)’ Sitz. Math.-Naturw. Classe, K. Akad.
Wissensch. Wien, vol. lxxxviii, pt. 1 (1883) pp. 538-69. —

% * Ammonites Pyriteuses des Marnes Valangiennes du S.E. de la France’
Mém. Soc. Géol. France, Paléont. vol. xv (1907) p. 65.

4 N.U.C.=Teaching Collection, University College, Nottingham ; N.M.=
Natural History Museum, Nottingham ; B.—Teaching Collection, Birmingham
University.

54 PROF. H. H. SWINNERTON AND MR. A. E. TRUEMAN [ vol. lxxiil,

one case of asymmetry. Further, asymmetry of a similar character
has been observed by previous writers in a large number of other
forms :— :
Ammonites miserabilis Quenstedt (Agassiceras Hyatt).
Ammonites falcaries Quenstedt.!
Oxynoticeras heteropleurum Neumayr & Uhlig.”
Hoplites oxygonius Neumayr & Uhlig.”
Engonoceras pierdenale var. commune Hyatt.*
Engonoceras uddeni Cragin.’
Oxynoticeras guibali Hyatt (‘Genesis of the Arietide’ 1889, p. 219 &
pl. x, fig. 28).
Cosmoceras jason (d’Orbigny).'
Cosmoceras m. f. jason Reinecke, C. pronie Teisseyre,* C. pollua Reinecke,
C. subnodatum, C. jenseni Teisseyre (op. cit. 1884, pp. 538-69).
Ammonites convolutus Schl. (Fraas, op. cit. 1868, p. 111).
Ammonites denarius, fittoni, lyelli Leymerie.*
Ammonites coregonensis Sowerby, Wehneroceras guidoni (Sowerby).®
Ammonites suessi, A. abnormalis, von Hauer.’

It will be noted that the greater number of the fossils in which
this type of asymmetry has been observed are included in, or
eonnected with, the families Cosmoceratide, Agoceratide, and
Stephanoceratide (according to the classification adopted by
J. P. Smith). Thus it would at first appear that the feature is
of considerable systematic importance; yet it should be remem-
bered that, although asymmetry is typical of certain species of
Hoplites, in other species of the same genus we have not observed
it. The presence or absence of examples of asymmetry, therefore,
must not be taken as conclusive evidence of relationship in the face
of other facts.

An examination of the lists just given shows that nearly every

specimen in which this type of asymmetry has been observed has —

a rounded or flat venter. Although at least a third of the
specimens. examined had keeled venters, not one case of asymmetry
has been detected by us among them. It would thus appear that
the displacement is to a large extent associated with the shape of
the whorl. Nevertheless, asymmetry may occur occasionally’ in

| F. A. Quenstedt, ‘Die Ammoniten des Schwabischen Jura’ Stuttgart,
1885, pl. xii, figs. 15, 29.

2 M. Neumayr & V. Uhlig ‘ Ueber Ammoniten aus den Hilsbildungen Nord-
deutschlands.’ Paleontographica, vol. xxvii (1880-81) pp. 135, 171.

3 A. Hyatt, ‘ Pseudoceratites of the Cretaceous’ U.S. Geol. Surv. Monogr.
xliv (1903) pp. 159, 165.

4 A. dOrbigny, ‘ Paléontologie Francaise: Terrains Oolitiques ou Juras-
siques’ vol. i (1842) p. 448.

5 M. Neumayr & V. Uhlig, Paleontographica, vol. xxvii (1880-81) pp. 219-
Do.
6 P. Savi & G. Meneghini, ‘ Osservazioni stratigrafiche & paleontologiche
concernenti la Geologia della Toscana’ 1851, pp. 73-77.

7 F. R. von Hauer, ‘ Ueber einige unsymmetrische Ammoniten aus den
Hierlatzschichten’ Sitz. Math.-Naturw. Classe, K. Akad. Wissensch. Wien,
vol. xiii (1854) pp. 401-410.

* Cephalopoda, in K. von Zittel’s ‘Text-book of Paleontology’ (transl.
Eastman), 2nd ed. (1913) p. 150.

%

part 1] ON THE MORPHOLOGY OF THE AMMONITE SEPTUM. 55

some keeled forms; for it has been recorded in Ammonites
miserabilis Quenstedt, in Oxynoticeras heteropleurum, and in
O. guibali. In the latter genus, at all events, the: exception is
only apparent, for the venter may be strictly considered as rounded,
on account of the hollow keel.! 7

Asymmetry has been observed in Hoplites tuberculatus by
G. C. Crick,” but here it was accompanied by a distortion of the
shell; yet a specimen with asymmetric ornament may have a
normal suture, as seen in an example of Ammonites amaltheus.?

The asymmetry which occurs so commonly in Hoplites splendens
and H. raulinianus is usually accompanied by the displacement
of the siphuncle into the angle bounding the flat venter. At
12 mm. diameter in each of the specimens the sutures were sym-
metrical, and at this stage the specimens had round venters
(PL IV, fig. 5@). From this stage until a whorl later (PI. IV,
fig. 5d) the siphuncle became gradually more displaced ; but only
the ventral part of the septum became distorted, for all the
features dorsal to the first lateral lobe remained normal. Sunilar
characters were observed by A. d’Orbigny* in the development of
asymmetry in Ammonites denarius. “Asymmetry in these cases
is probably a growth phenomenon, associated with the tendency
of the siphuncle to take up a stable position along the angle
bounding the venter.

Accompanying the displacement there has been in many forms
a rapid change in the form of the suture, which is probably a
result of the increased area on that side of the siphuncle. It
illustrates the manner in which the form of a suture may be changed
owing to a rapidly increased height of whorl. Thus in Hoplites
splendens (Pl. IV, figs. 4-6) the external saddle at first has two
main divisions; but later it becomes trilobed. F urther, in Cosmo-
ceras (Pl, IV, fig. 10) the external saddle of the enlarged side 1s
practically double the breadth of the corr esponding saddle of the
other side. In association with this increase in relative size the
saddle has become more deeply denticulated, and the major frillings
have become indented by numerous minor frills which are rae
feebly represented on the other side. This peculiarity has been
studied in some detail by Teisseyre.®

He suggested that the displacement that we have described
is a erowth- phenomenon associated with the form of the whorl.
Solger® believed that the movement of the siphuncle away from
the median plane was due to the adoption of a recumbent habit.

! A, Hyatt, Smithsonian Contributions to Knowledge, No. 673 (1889) pl. x,
fig. 28.

2 « A deformed example of Hoplites twberculatum, Geol. Mag. dee. 4; vol. v
(1898) p. 541.

3 OQ, Fraas, Jahreshefte Wiirttemberg. xix, 18638, p. 111.

4 A. dOrbigny, ‘ Paléontologie Francaise: Terrains Crétacés’ vol. i (1840)
p. 222.

’ L. Teisseyre, Sitz. Math.-Naturw. Classe, K. Akad. Wissensch. Wien,
vol, lxxxviii, pt. 1 (1883) pp. 604-608.

6 FE, Solger, ‘ Beitriige zur Geologie von Kamerun, 1904.

56 PROF. H. H. SWINNERTON AND MR. A. E. TRUEMAN | vol. ]xxin,

Dr. O. Abel! considers that, while many ammonites were adapted
for a swimming life, yet many of the ‘one-sided’ forms that we
have mentioned had a benthic habit. He also suggested that the
presence of a keel in a nectonic animal would assist rapid motion.
As we have seen, asymmetric siphuncles rarely occur among these
keeled forms, which presumably had rarely.a benthic habit.

Briefly then, although a displaced siphuncle and an
asymmetric suture may be most usually developed in
certain connected species, the existence of such ab-
normalities in a single specimen is not sound evidence
of genetic affinity.

In conclusion, we wish to express our thanks to those who have
helped us: to W. D. Lang, M.A., F.G.S., for gifts of material ;
to Prof. J. W. Carr, M.A., F.G.S., for permission to examine the
collection in the Nottingham Museum ; and to Prof. W. 8. Boulton,
F.G.S., for allowing us similar access to the collection in the
Birmingham University.

EXPLANATION ‘OF! PLATES Ui

PrateE II.

Fig. 1. Apparatus used in surveying and levelling the surfaces of septa and

of whorls,

2. Dactylioceras commune (J. Sowerby), from Whitby. Specimen used
for working out the development of the septum, the suture-line, and
for making septal sections. Diameter=7°5 cm. X 32.

3. Portion of the whorl of another specimen of the same species filed
away in steps, in order to show septal sections of successive septa.
«x 1.

4, Series of septal sections drawn from this specimen.

PLATE III.

Figs. 1-5. Development of the septum of Dactylioceras commune. Figs. 2-5
are from the specimen shown in PI. II, fig. 2.
Fig. 1. Adult septum. xX 4°5. (Text-fig. 4.)
2. Septum at 23? whorls. x 22.
3. Do. at 21 whorls. x 25.
4: > Do. at 1 whorls. ?°X Sp: | The numbering of figs. 4
5. Second septum. x 40. (Text-fig. 6, p. 36.) & 5 should be reversed.
6. Almost adult septum of Tragophylloceras loscombi (J. Sowerby), from
Lyme Regis, Diameter=17 mm. x 6.
7. Adult septum of Spheroceras brongniarti (J. Sow erby), from Sher-
borne. Diameter=20 mm. x 2}.

PLaTe IV.

Figs, 1-3. Perisphinctes triplicatus, from Market Rasen.

Fig. 1. Front view of an abnormal septum. Natural size.
2. Ventral view of a portion of an outer whorl. Natural size.
3. Last suture shown by this specimen,

1 * Verbreitung & Lebensweise der Ammoniten’ Verhandl, k.-k. Zool.- Botan.
Gesellsch. Wien, 1912, p. 83.

Quart. Journ. Geov. Soc. Vor. LXXII, Pu. I.

A.E.T., del.

Bemrose, Collo. Derby.

DEVELOPMENT oF THE AMMONITE SEPTUM.

Derby.

Bemrose, Collo.,

Quart. Journ. Geor. Soc. Vor. LXXIII, Pr. iil.

DEVELOPMENT oF tHe SEPTUM of DACTYLIOCERAS COMMUNE, etc.

AE.T,, dei.

QUART. JOURN. GEOL. Soc, VoL. LXXIlII, PL. IV.

14. 15.

A.E.T,, Del.
DEVELOPMENT oF THE AMMONITE:SEPTUM.

_ part 1] ON THE MORPHOLOGY OF THE AMMONITE SEPTUM. 57

Figs. 4-6. Hoplites splendens. Diameter=34 mm.
Fig. 4. Septum showing displaced siphuncle, and distortion associated there-
with.
’ 5a. Suture of the same at 12 mm.
3b. °- Do. do. at 32 mm.
6. Do. of another specimen.
7. Hoplites raulinianus. Folkestone. Suture.
8. Hoplites awritus. Cambridge. View of venter showing displacement
of the siphuncle, first to one side and then to the other.
°9. Psiloceras planorbis. Robin Hood’s Bay. Showing position of dis-
placed siphuncle. . . :
Figs. 10-15. Asymmetrical sutures of various ammonites.
Fig. 10. Cosmoceras jason. Buckinghamshire.
11. ‘ Normannites’ braikenridgi. Mesvil.
12. Aspidoceras perarmatum. Faringdon.
13. Uptonia jamesoni.
14. Keplerites calloviensis. Ashton Keynes.
15. Dactylioceras commune. Whitby.

IL=Internal lobe. ES=External saddle. L!=Principal or first lateral lobe.
L*=Auxiliary lobe. S!=—First lateral saddle. M=Median plane. Sip.=
Siphuncele.

DISCUSSION.

Dr. F. A. Barner thanked Prof. Swinnerton for his well-
illustrated and lucid exposition. It had been said that in science
the invention of a new method was worth more than the discovery
of a hundred facts. The instrument devised by the Authors might
be applied to the reproduction of other complicated surfaces. ‘The
ammonites illustrated had all been progressive types, and appa-
rently the method was unsuitable when retrogression had set in.
In progressive types the study of a late- formed | septum enabled one
to oak backwards, but not for wards, to the unknown. Might it
not, however, be possible to forecast the lines of retrogression ¥ In
any case, the method would facilitate the determination of affinities
and the plotting-out of definite series on which more secure in-
ferences could be based.

Dr. A. M. Daviss said that the suggestion that septal sections
might be used as a means of studying the development of the
septum had been made to him in conversation by Mr. 8. 8. Buck-
man some years ago. He congratulated the “Authors on their
success 1n demonstrating the truth of this suggestion. Heenquired
as to how far coarse ornamentation would interfere with the applica-
tion of the method, and whether it was really trustworthy in the
case of septa which had undergone catagenetic simplification.

Prof. H. H. Swinnerron thanked those present for the kind
reception g given to the paper. Replying to Dr. Bather, he stated
that ‘ septal sections’ supplied a standard of the most direct line
of development leading up to the condition found in the particular
septum from which they had been made; for that reason they would
not record any deviations from that line occurring during evolu-
tion or development. The study of the septal sections of a simple

J. GS. No. 289. ¥

THE MORPHOLOGY OF THE AMMONITE SEPTUM. | vol. Ixxiit.

septuin could not be expected to throw light upon the possible
complications which might arise in the future ina progressive series.
On the other hand, sections of a complicated septum such as that
of Lytoceras might reasonably be expected to show resemblances
to the sutures of any species of Baculites otf Lytoceratan ongin.

Replying to Dr. Davies, he expressed the opinion that the presence
of coarse ornamentation on the surface of an ammonite would not
seriously impair the usefulness of septal sections. The resemblance
of the inner part of the septum to the early septa was not really
an example of the phenomenon defined in the phrase ‘localized
stages in development.’

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part 2] ACLISINA AND ACLISOIDES. 59

4. SUPPLEMENTARY Notes on AcLis1vA DE KonincK and ACLI-
SOIDES DONALD, with Descriptions of NEw Species. By
JANE LonestaFF (née Donan), F.L.S. (Communicated

by Dr. G. B. Lonestarr, M.A., F.G.S. Read May 2nd,
pegs...)

[Puates V & VI.]

In 1898 I communicated a paper to this Society on the genus
Aclisina and on Aclisoides, a new section or subgenus of Murchi-
sonia. Since that date I have had the opportunity of studying
a larger number of specimens, which has not only enabled me to
learn more about the species then described, but also to add to
their number.

Fifteen species of Aclisina with several varieties, and a single
species of Aclisozdes with one variety, were dealt with in 1898. I
am now referring seven more species to the former, six of which have
not been previously noted, and am regarding the form considered
a variety of the latter as a distinct species. Thus we have a total
of twenty-two possible species of Aclistna and two of Aclisoides.
In addition to these there are in the Sedgwick Museum, Cambridge,
three small shells resembling Aclzsena, one from Poolvash, the
others from Settle, all too much embedded in the matrix to be
accurately determined.

The numbers given can only be regarded as approximate, for
paucity of specimens and defects in the manner of preservation
sometimes render the definition of genera and species difficult. It
is, therefore, possible that some shells at present considered as
distinct species may afterwards prove to be varieties only, while
others now grouped together may need to be separated.

In the previous paper no holotypes were selected. JI am now
supplying the omission, and also stating in which collections they
are deposited.

Although I have already remarked on the beautiful state of
preservation of many of the Scottish specimens, it may not be
amiss to draw attention to it again. No less than thirteen species
of Aclisina and one of Aclisoides have the protoconch well pre-
served. In the latter it is attached to the post-embryonic whorl
and simply coiled on the same plane, and thus in no wise peculiar.
But in Aclisina it is markedly so, being more or less irregular.
In six species the protoconch stands up, forming a wide angle with
the post-embryonic whorl; in four it is not so much raised, but is
oblique and overhangs the spire; in the remaining three it is
wholly attached, forming a broad flat apex. ;

The material at hand is not sufficient to show to how great an
extent variation in the character of the protoconch of a species m; OE Rae
take place, either in the same beds, or in those separated by ti a SONIA ge h

QoJ.G. 8. No. 290: arf

60 MRS. JANE LONGSTAFF ON [vol. lxxiu,

space. In no instance have I observed a species including indi-
viduals with the protoconch greatly elevated and others with it flat.
In two species, Aclisina micula and A. striatissima, I have noted
very slight variation. Only two examples of the former are known
to me: in one the protoconch adheres closely, in the other it is a
little raised, and in one example of A. striatissima (PI. VI, fig. 4)
it is flatter than in the type. In some shells one or more of the
upper whorls of the spire are unattached, as well as the protoconch :
as, for instance, A. aciculata (Pl. VI, fig. 6). The protoconch is
frequently more translucent than, or of a different colour from,
the rest of the shell.

I have previously noted that the Scottish Gasteropoda as a
whole are small. There are, however, exceptions to this, for at
Craigenglen and Strathavon, both near the base of the Lower
Limestone Series, larger shells occur, equalling in dimensions indi-
viduals of the same species at Settle and Visé. Mr. Peter Macnair
suggests that this may be the result of the clear-water conditions
which prevailed during the deposition of the beds at these localities.
It is remarkable that the most minute examples occur at Glencart,
Dalry, near the top of the Upper Limestone Series; the peculiar
character of the deposit in which they were found was described
by Dr. John Young, and also referred to by me.

Aclisina and <Aclisoides are not associated together in this
paper on account of a supposed close relationship, but because,
owing to a superficial resemblance, a species of the latter had been
mistaken for a member of the former. I have discussed the
possible affinities of Aclis¢na, and have shown that it bears a great
likeness to Promathildia Andree, which genus was then included
by some paleontologists in the family Turritellide. Koken con-
sidered that Aclisina might be the direct forerunner of certain
Turritelle. M.Cossmann has since created the family Mathil-
diidee:! thus it is now a question whether Ac/zs¢na should not
find a place there in proximity to Prumathildia. If this were
the case, Aclisina would be the most ancient member of the group
as now constituted.

A far greater number of species of Aclistna have been found in
Scotland than in any other country. Of the twenty-two recorded
only one is peculiar to England, and one, or at most two, to
Ireland. The former is the fossil described by Mr. Bolton as
Loxonema ashtonense from the basement-beds of the Bristol Coal-
field. One of the Irish species, A. swleatula (McCoy), has not
been observed elsewhere ; the other, A. polygyra (McCoy), is pro-
bably conspecific with 4. elongata (Fleming), but the holotype is
so much embedded in the matrix that it is difficult to be certain

of this.
With regard to the species occurring in Scotland, it may be

1 « Hssais de Paléoconchologie Comparée,’ vol. ix (1912) p. 2. After writing
the above I received vol. x (1915) of this work, and I observe that on p. 259
M. Cossmann does not consider Aclisina to be related to Twrritella, but
states that ‘ intermédiaire entre Loxonema et Mathildia est manifeste.’

part 2} ACLISINA AND ACLISOIDES. 61

noted that the variety exigua of Aclisina pulchra De Koninck and
A. elongata (F leming) have the most extended range, the former
making its appearance in the Calciferous Sandstone Series, and
continuing throughout the Lower Limestone Series and the Upper
Limestone Series into the Millstone Grit. In Belgium the species
is only recorded from Tournai, where specimens attain a greater
size than any Scottish variety that I have seen. A. elongata has
a sunilar range in Scotland, except that it has not been recorded
from the Millstone Grit. It also occurs in the Yoredale Series
of England, and is probably represented in Ireland and Belgium.
L. G. de Koninck figures a small gasteropod from Visé on pl. xxxiii,
figs. 45 & 46, in ‘ Faune du Calcaire Carbonifére de Belgique ’
pt. iv, Ann. Mus. Roy. Hist. Nat. Belg. vol. viii (1883), which
greatly resembles this species; but it 1s undescribed, as it was
lost.

Eight species occur in both the Lower and the Upper Limestone
Series: namely, A. costatula, A. attenuata, A. aciculata, A. tenui-
striata, A. quadrata, A. similis, A. striatissima, and A. ? multi-
volva. Of these, A. s¢milis and probably A. striatissima are
found also in Belgium.

Five species are confined to the Lower Limestone Series: namely,
A. pusilla, A. parvula, A. terebra, A. elegantula, and A. venusta.

Four are limited to the Upper Limestone Series: namely,
A. delicatula, A. fuber, A. micula, and A. subelongata.

A. grantonensis has only been found in the Calciferous Sandstone
Series.

Of the two species referred to Aclisoides, A. striatula has the
widest range, occurring in both the Lower and the Upper Lime-
stone Series of Scotland, as well as in England, the Isle of Man,
and Belgium; while A. ? armstrongiana is only known from the
Lower Limestone Series of Scotland. This subgenus is confined
to the Carboniferous Period. |

In addition to the fourteen foreign Carboniferous species of
Aclisina previously mentioned, three have been described by
Miss Clara G. Mark,! and three others have been doubtfully re-
ferred to the genus by her; these latter, however, do not appear
to possess the characteristic lines of growth. The three former
are A. formosa, A. conditi, and A. pumila, from the Portersville
Limestone, Conemaugh Formation.

Besides these, a new species from the Zechstein, 4. beneventa,?
has been described by E. Dietz, and also one from the Devonian,
A. fugitiva Barrande, by Dr. Jaroslav Perner.

This: genus has been stated to rae from the Devonian to the
Permian : if, however, the species A. obscura Donald,* doubtfully

1 Geol. Surv. Ohio, ser. 4, Bull. 17 (1912) p. 314 & pl. xvi, figs. 7-10.

2 Jahrb. K. Preuss. Geol. Landesanst. vol. xxx, pt. i (1911) p. 475 &
pl. xv, fig. 1.

3 «Systéme Silurien du Centre de la Bohéme, vol. iv: Gastéropodes’ vol. ii
(1907) p. 372 & pl. ex, figs. 19-20.

4 Q. J. G.S. vol. lviii (1902) p. 337 & pl. ix, fig. 12.

62 MRS. JANE LONGSTAFF ON [vol. lxxiu,
referred to it from the Silurian, prove to be a true member, its
origin must be more ancient.

I am greatly indebted to both Mr. R. G. Carruthers and
Mr. Peter Macnair for information respecting the horizons at
which the Scottish species occur. Their views agree in the
main with regard to the Upper Limestone Series. But for the
Lower Limestone and Calciferous Sandstone Series I have been
guided by Mr. Macnair, whose recent extensive studies of the
stratigraphy of these beds have led him to differ from the Geo-
logical Survey. He considers that there is no marked break
i een the strata of the Calciferous Sandstone Series and the
succeeding Lower Limestone Series, and refers to the latter all
the sedimentary rocks (including the Hollybush Limestone) that
occur above the Calciferous- Sandstone lavas of the West of
Scotland.

In Proc. Geol. Assoc. vol. xxvi, pt. 3 (1915) p. 179, he describes

the remarkably fine sections at Corrie Burn, Kilsyth (Stirlingshire),
and on p. 1Si sums up thus:
‘The main points of difference between this reading of the succession and
that of the Geological Survey is that in the north of Ayrshire they take the
Dockra Limestone as the Hurlet, the four succeeding limestones being respec-
tively the Blackhall, Main Hosie. Mid Hosie, and Top Hosie. In Fife they
take the Seafield Limestone as the Hurlet; this is my Main Hosie. In the
Bilston Burn, Midlothian, they take the Gilmerton Limestone as the Hurlet,
whereas my Hurlet datum-line lies about 200 feet below the Gilmerton
Limestone.’

Mr. Macnair regards the Dockra Limestone as underlying the
Hurlet, and as being equivalent to the Blackbyre Limestone of
Kilsyth, Campsie, and Hurlet. In several communications to the
Geological Society of Glasgow, published in their Transactions
during the years 1912-16, ‘he supplies further details, and deals
with the correlation of these strata with those in Lanarkshire.

No species of Aclisina and Aclisoides have been recorded from

the Hurlet Limestone as here defined; this is not, however, —

remarkable, since they are mostly smail forms, and Mr. John
Smith! states that there is a great scarcity of fossils in this
stratum.

The beds at Penton Linns (Dumfriesshire) have not been care-
fully zoned, therefore it is impossible to state the exact position of
those from which the gasteropods here described are derived. The
undersides of* the slabs are crowded with Productus longispinus
Sowerby, and there are numerous spines and fragments of the
brachiopods above. Dr. J. Horne & Dr. B.N. Peach 2 give a short
list of fossils from this locality in their account of the Canonbie
Coalfield, and state that they recall the assemblage of organic
remains of the Lower Limestone Series of Central Scotland.

The exact relationship of the Scottish strata with the English
has not been thoroughly worked out, therefore the reference to

' Trans. Geol. Soc. Glasgow, vol. xiv, pt. ii (1911) p. 141.
2 Trans. Roy. Soc. Edin. vol. xl (1903) p. 850.

part 2] ACLISINA AND ACLISOIDES. 63

the late Dr. Arthur Vaughan’s zones can only be regarded as
temporary and approximate.

Prof. E. J. Garwood has very kindly given me his views, based
on the information at present available. He considers the Lower
Limestone Series to be homotaxial with D,—D,, and the Upper
Limestone Series with D,—-? D,. The Settle “Limestone is S,
and D,. Widdale Fell, Mosedale, is Dy.

The Upper Limestone of Poolvash (Isle of Man) is probably
D—D,. Mr. J. Smith’s gasteropoda came from the partly dolo-
mitized upper limestone east of the Balladoole Fault, Poolvash.
He believes the horizon to be lower than that of the Hurlet
Limestone of the West of Scotland.

With regard to the Irish localities, Cullion, Draperstown, and
Carrickoughter, Kesh, Prot. G. A. J. Cole states that the districts
require careful zoning before the exact positions can be ascertained.
Dr. Vaughan considered that the former might be homotaxial
with C, of the Avon Section. The latter is probably at a much
higher horizon.

A table is appended (pp. 64-67) with names of species, localities,
and the Scottish horizons. These latter are, for the greater part,
called after the characteristic limestone ; the fossils, however, are
by no means restricted to that stratum, but are frequently found
in the associated shales. There being very few records outside
Scotland, it has not been considered necessary to give additional
columns for their horizons, more especially as they are not very pre-
cisely defined at present. Since the localities are fully dealt with
here, they are given under the descriptions only in the case of
holoty pes and rarer species. Also those alone from which I have
actually seen specimens myself are stated. I have examined many
of the gasteropoda to which names have been given in the Scottish
Geological-Survey lists, and I find that these names are not in all
cases to be depended upon. Confusion has probably arisen from
eratting more recent nomenclature on the older. For instance,
I have met with five distinct species referable to at least two
genera, all grouped under one specific name, which was not
applicable to any one of them. On the other hand, a single species
occurs under two different names.

In order to save space, only such parts of the synonymy are
repeated as are essential for clearness.

Most of the small specimens were drawn with the camera lucida
on the microscope, and the approximate magnification is given in
each case.

For the loan of specimens I offer my most hearty thanks to
those in charge of the Geological Survey Collections in London
and Edinburgh; to the Council of the Hancock Museum, New-
castle-upon-Tyne ; to the late Prof. McKenny Hughes, Sedgwick
Museum, Cambridge; to Dr. Ritchie, Royal Scottish Museum,
Edinburgh; to Mr. Peter Macnair, Glasgow Museum, Kelvin-
grove; and to Mr. Herbert Bolton, Bristol Museum. I desire
also to express my gratitude to Mr. Robert Dunlop, Dunfermline,

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68 MRS. JANE LONGSTAFF ON (vol. Ixxiii,

Mr. James Wright, Kirkcaldy, and Mr. John Smith, Dalry, for
the privilege of examining examples in their private collections.
Further, for assistance in many ways I am greatly obliged to
Dr. A. Smith Woodward, F.R.S., Dr. F. A. Bather, F.R.S., Prof.
E. J. Garwood, F.R.S., Dr. F. L. Kitchin, the late Mr. G. C. Crick,
Dr. F. R. Cowper Reed, Dr. Lee, Prof. S. H. Reynolds, Prof.
G. A. J. Cole, M. Louis Dollo, and M. Douvillé.

Genus Aciistna De Koninck.

ACLIsINA PULCHRA De Koninck. (PI. V, figs. 1 & 2a—2 0.)

Aclisina pulchra De Koninck, 1881, ‘ Faune Calc. Carb. Belg.’ pt. iii, Ann.
Mus. Roy. Hist. Nat. Belg. vol. vi, p. 87 & pl. vii, figs. 26-27.

Remarks.—L. G. de Koninck represents this species as
having the whorls ornamented by seven or eight spiral grooves and
ridges of equal size. In reality, however, the upper ridges, from
1 to 3 in number, are finer than the three or four below, and on the
body-whorl these latter are followed by numerous still finer ridges,
one or two of which frequently show above the suture on the
penultimate whorl. On the earlier whorls only one of the three
finer ridges exists, it is immediately below the suture. None of
the Belgian specimens that I have seen has the apex intact. The
sigmoidal form of the outer lip is well preserved in a specimen
(Pl. V, fig. 2) in the collection of Canon H. de Dorlodot: this
character is only indicated by the lines of growth in all the other
species of the genus that I have examined.

So far, | have not met with any typical specimens of this species
in the British Isles. .

Holotype.—Op. cit. pl. vii, figs. 26 & 27. Also Pl. V, fig. 1 of
this paper.

There are two smaller examples associated with the holotype in
the Musée Royale d’Histoire Naturelle at Brussels, also a good
specimen in the British Museum (Natural History), and I have
two others purchased trom M. Piret.

Locality and horizon.—Tournai (Assise 1).

ACLISINA PULCHRA, var. EXIGUA, NOM. NOV.

Aclisina pulchra vay. tenuis (De Koninck) Donald, 1898, Q. J. G. S. vol. liv,
p. 52 & pl. in, figs. 1-4.

Remarks.—I referred a small Scottish variety of A. pulchra
to Murchisonia tenuis De Koninck, because I found that it agreed
with the best-preserved shells on a tablet so named in the Brussels
Museum. During a subsequent visit a further examination of
this tablet convinced me that there were two distinct species on
it. ‘The specimen marked as holotype is much worn, and has only
three somewhat coarse threads ornamenting the whorl; two of the
eight examples associated with it are the same, and they all look
like immature shells. The remaining five are different, and are
conspecific with the Scottish shells. These latter greatly resemble

part 2 | ACLISINA AND ACLISOIDES. 69

the typical A. pulchra, but they are much smaller and rather
more slender. At least eight and twenty Scottish specimens are
remarkable for having the protoconch intact, and some also exhibit
the characteristic sigmoidal lines of growth.

Holotype.—Op. cit. pl. iu, fig. 2. In the Neilson Collection,
Royal Scottish Museum, Edinburgh.

Locality and horizon. —Robroyston, Glasgow, in the Upper
Limestone Series.

Unfortunately the finer specimen (fig. 1) from Swindridge Muir,
Ayrshire, also in the Upper Limestone Series, has perished by fire.
There are, however, numerous examples from this locality in the
Young, Neilson, and my own collections.

Specimens in Mr. J. Smith’s collection from the Index Lime-
stone at Highfield, Dalry, and Dernshaw, Stewarton, have the
protoconch preserved, as well as those previously mentioned from
the last-named locality.

ACLISINA PULCHRA, var. INTERMEDIA Donald.
Aclisina pulchra, var. intermedia Donald, 1898, op. cit. p. 53 & pl. ui, figs. 5-da.

Remarks.—Specimens previously referred to this variety from
Swindridge Muir are most probably A. costatula.

Holotype.—Op. cit. pl. iu, figs. 5 & 5a. Bennie Collection,
Royal Scottish Museum, Edinburgh.

Locality and horizon.—Law, Dalry (Ayrshire), in the Lower
Limestone Series.

ACLISINA VENUSTA, sp. nov. (PIL. V, figs. 83a & 30.)

Diagnosis.—Shell elongated, conical, composed of more than
seven whorls. Whorls convex, ornamented on the lower part by
four threads, the two upper of which are the strongest and farthest
apart; midway between these and the suture are two finer ones, and
on the body-whorl there are two additional fine threads below.
Sutures deep. Base convex, slightly produced. Inner lip reflected.
Columella nearly straight.

Remarks.—From A. pulchra this species may be distinguished
by being more slender and having more regularly convex whorls.
It is most like the variety ¢ntermedia, but is of much gteater size,
and has also two fine threads on the upper part of the whorl. We
have, however, only one example of each of these forms; it is
therefore possible that the discovery of intermediate links might
prove them to be the extremes of a single species or variety.

Holotype.—PI. V, figs. 3a & 3 b, Bennie Collection, Royal
Scottish Museum, Edinburgh.

Dimensions.—Length=8 millimetres ; width=3 mm.

Locality and horizon.—Law, Dalry, in the Lower Limestone
Series.

70 MRS. JANE LONGSTAFF ON [ vol. lxxiu,

ACLISINA FABER, sp. nov. (PI. V, figs. 4 & 5a-5 c.)

Diagnosis.—Shell small, conical, composed of more than nine
whorls. Whorls broad, convex, slightly flattened above and sub-
angular near the middle. Lower part ornamented by six moderately
strong threads with two additional ones on the body-whorl; upper
part ornamented by three fine threads; base covered by numerous
still finer ones. Protoconch composed of little more than one
smooth volution, moderately raised and slightly overhanging the
succeeding whorl. Aperture subcircular. Columella nearly straight.
Inner lip reflected.

Remarks.—This species somewhat resembles 4A. pulchra, but
it has more convex whorls ornamented by finer and more numerous
threads, also the protoconch is more orbicular and not so erect.
~~ Holotype.—tThe larger specimen represented in PI. V, fig. 4,
must be regarded as the holotype; it consists of nine whorls the
length of which=6 mm., and the width=2°5 mm. The smaller
shell (tig. 5) is remarkable for having the protoconch intact; its
length=1°'75 mm. Both are in Mr. John Smith’s collection.

Locality and horizon.—High Smithston, Kilwinning (Ayr-
shire), in the Upper Limestone Series.

Three small shells in my own collection appear to belong to this
species. They are from Glencart, Dalry, also in the Upper Lime-
stone Series.

ACLISINA COSTATULA Donald.
Aclisina costatula Donald, 1898, op. cit. p. 56 & pl. iii, figs. 12-14.

Holotype.—Op. cit. pl. 1, fig. 12. Longstaff Collection.
Locality and horizon. — Penton Linns, Liddel Water (Dum-
friesshire). Lower Limestone Series.

ACLISINA COSTATULA, var. DUBIA Donald.
Aclisina costatula var. dubia, Donald, 1898, op. cit. p. 57 & pl. ii, fig. 18.

Remarks.——The examination of a large number of specimens
shows that A. costatula exhibits a certain amount of variation. I
suggested the name dubia for a large variety having somewhat
higher whorls. Unfortunately the original example has perished
by fire with the late Mr. Thomson’s collection. There is, however,
a shell in Mr. J. Smith’s collection greatly resembling it in every
way. It*has six whorls intact, which have a length of 5°65 milli-
metres.

Locality and horizon.—Whereas the original was from
Craigenglen, Campsie (Stirlingshire), in the Lower Limestone
Series, this specimen is from Moss Mullock, in the Upper Lime-
stone Series.

ACLISINA ATTENUATA Donald.

Aclisina attenuata Donald, 1898, op. cit. p. 58 & pl. iv, tigs. 2-3.
Holotype.—Op. cit. pl. iv, fig. 2. Longstaff Collection.
Locality and horizon.—Glencart, Dalry, in the Upper

Jimestone Series.

[=

> part 2] ACLISINA AND ACLISOIDES. 71

ACLISINA DELICATULA, sp. nov. (PI. V, figs. 6a—-6c.)

Diagnosis.—Shell slender, composed of eleven gradually in-
ereasing whorls. Whorls convex, broad and low. Ornamentation
consisting of tive moderately strong threads on the lower part of
each whorl, with numerous additional finer ones below on the body-
whorl; higher part of the whorl apparently smooth. Lines of
growth unknown. Apex broad and nearly flat. Protoconch con-
sisting of about one smooth whorl coiled on almost the same plane
as-the rest of the spire to which it is attached. Base convex, but
little produced. Noumbilicus. Aperture ovoid. Columella nearly
straight, curving round at the bottom to meet the outer ip. Inner
lip reflected on the body-whorl.

Remarks.—This species resembles A. costatwla in ornamenta-
tion, but the form is not so slender and the whorls are more
conyex. The protoconch of the only known specimen is intact,’
but is somewhat worn, and probably is slightly crushed, so that it
may not originally have been so flat.

Holotype.—PL V, figs. 6a—6c. In my own collection, given
to me by the late Dr. John Young.

Dimensions.—Length=4°25 millimetres; width=1:4 mm.

Loeality and horizon.—Glencart, Dalry, in the Upper Lime-
stone Series.

ACLISINA MICULA, sp.nov. (Pl. V, figs. 7a & 70.)

Diagnosis.—Shell elongated, composed of about ten slightly
convex “whorls. Whorls broad, ornamented on the lower two-thirds
by four threads, the two upper are the strongest and farthest
apart ; two additional fine threads on the body-whorl. Sutures of
moderate depth. Base not produced. Aperture rounded. Proto-
conch flat and broad, attached to, or but slightly raised from, the
spire.

wiles rks.—Achsina micula may be distinguished from

A. costatula by its greater spiral angle, shallower sutures, more
compactly coiled whorls, and in the protoconch being attached to
the spire instead of standing up. It differs also from A. attenuata
in being less slender, and in the lower threads being coarser. The
only two specimens that I have met with show the protoconch
intact; it adheres closely on one, while on the other (the holotype)
it is very slightly raised.

Holotype.—PIl. V, figs. 7a & 76. Smith Collection.

Dimensions. —Length= 3°5 millimetres; width=1 mm.

Locality and horizon.—High Smithston, Kalwinning. Upper
Limestone Series.

The other example is from Moss Mullock, Kilwinning, at the
same horizon and in the same collection.

Acuistna stmi~is Donald. (PI. V, fig. 8.)

Aclisina similis Donald, 1898, op. cit. p. 57 & pl. iii, fig. 16, pl. iv, fig. 1.
Aclisina pusilla Donald, 1898, pars, op. cit. p. 63 & pl. iv, fig. 15 [exclude
figs. 14, 14a, & 146.]

72 MRS. JANE LONGSTAFF ON [ vol. lxxin,

Remarks.—About sixteen specimens of this species have been
examined, but only one has the protoconch intact (Pl. V, fig. 8).
It is in Mr. J. Smith’s collection, and was found by him at High
Smithston, in the Upper etnias Series.

Holoty pe.—Op. cit. pl. iv, fig. 1. Bennie Collection, Royal
Scottish Museum, Edinburgh.

Locality and horizon.—Law, Dalry, in the Lower Lime-
stone Series.

AcLISINA PUSILLA Donald. (PI. V, fig. 9.)

Aclisina pes Donald, 1898, op. cit. p. 63 & pl. iv, figs. 14,l4a, & 146
‘exclude fig.

? Aclisina parv a Donald, 1898, pars, op. cit. p. 64 & pl. v, figs. 2,2 a, & 2b.
Remarks.—This species is distinguished by its slender form,
flattened whorls, and relatively broad, flat apex. The examination
of a number of specimens shows that there is a slight variation in
the strength of the ornamenting threads. The example of which
a portion of a whorl is figured (op. czt. pl. iv, fig. 15), from Glen-
cart, is really A. stmilts, a species which A. pusilla greatly
resembles; but the latter is smaller, the whorls are lower, and the
protoconch is flat. Several examples have the apex intact. It is
probable that figs. 2,2a, & 26 in pl. v. op. ect. represent an imma-
ture form of this species.

Holoty pe.—Op. eit. pl. iv, fig. 14. A figure (Pl. V, fig. 9) of
the protoconch of this shell is given, as that previously drawn
belonged to another specimen. Smith Collection.

Locality and horizon.—Law, Dalry. Lower Limestone
Series.

Besides the holotype there are six additional specimens in fe
Bennie Collection, and one in the Young Collection from Law,
Dalry; also seven from Dykes, Kilbirnie, in the Smith Collection.
They are all from the Lower Limestone Series.

ACLISINA ELONGATA (Fleming). (PI. V, figs. 10-12.)
Aclisina elongata (Fleming) Donald, 1898, op. cit. p. 54 & pl. iii, figs. 6-6 a.

Remarks.—It is unfortunate that the holotype should be an
exceedingly small specimen with the apex broken, consisting of
four and a half whorls in a length of 2 millimetres. All the
gasteropods from the same locality fae similar dimensions. Most
of the examples from Penton are of greater size; that figured in
op. ert. pl. in, fig. 6, is the largest, but it is not well preserved,
being greatly crushed. The enlarged portion of a whorl (fig. 6 a)
is part “of a fragment of a shell, showing the ornamentation and
contour distinctly, and on the same slab with it are two smaller
specimens fairly preserved, one of which has twelve whorls with a
length of 5:5 millimetres. Many of the examples from Law,
Dalry, exhibit the ornamentation and contour well, as they are
preserved in such a manner as to be easily detached from the matrix.
Mr. R. Dunlop possesses an exceedingly fine series of about forty

a

ACLISINA AND ACLISOJDES. 73

part 2]
specimens from Elie (Fife), which show a certain amount of varia-
tion in the ornamentation, there being intermediate forms merging
into the variety varians. In Mr. J. Smith's collection there is a
remarkably perfect young example with apex and aperture intact;
it consists of seven whorls besides the protoconch in a length of
2°25 millimetres (Pl. V, fig. 12). It is from Dykes, Kilbirnie
(Ayrshire), in the Lower Limestone Series. One of the best pre-
served shells was found at Crawtield, Beith, and is figured (PI. V,
fig. 11). .

Holotype.—Ure Collection, Royal Society, Edinburgh. PI. V,
fig. 10.

Locality and horizon.—Lauriston ( Brankam Hall), Lanark-
shire, in the Lower Limestone Series.

ACLISINA ELONGATA, var. VARIANS Donald. (PI. V, fig. 15.)
Aclisina elongata, var. varians Donald, 1898, op. cit. p. 55 & pl. iii, tig. 9.

Remarks.—This variety is especially well represented at Craig-
englen. In Mr. J. Smith’s collection there are two young
specimens with the protoconch intact; the back view of one is
given in Pl. V, fig. 15. They are from the Lower Limestone
Series at Dykes, Kilbirnie.

Holotype.—Op. cit. pl. iii, tig. 9. Ure Collection, Royal
Society, Edinburgh.

Loeality and horizon.—Lauriston (Brankam Hall), in the
Lower Limestone Series.

ACLISINA ELONGATA, var. CINGULATA Donald. (PI. V, figs. 13 & 14.)
Aclisina elongata, var. cingulata Donald, 1898, op. cit. p. 55 & pl. iii, figs. 10-
10a; ? figs. 7 a-7 c.

Remarks.—This variety is distinguished from the type by the
whorls being usually higher, as well as by the difference in orna-
mentation. An example larger than that previously figured is
given in Pl. V, figs. 134 & 134, as it shows the variation in the
ornamenting threads more distinctly. It is from the same locality,
and is in the same collection. The protoconch previously referred
to this variety (pl. iii, figs. 7a-7c) most probably belongs to
A. tenuistriata. ‘The specimen is contorted, and the ornamenta-
tion is indistinct. Mr. J. Smith has a remarkably well-preserved
example of this variety with the protoconch, which is figured in
Pl. V, fig. 14. Since the protoconchs of the typical form and
the two varieties resemble one another, only one figure of each is
given, taken from different aspects. They are all from Dykes.

Holotype.—9Op. cit. pl. iil, figs. 1O& 10a. Young Collection,
Glasgow Museum.

Locality and horizon.—Gleneart, Dalry, in the Upper Lime-
stone Series.

ACLISINA POLYGYRA (McCoy ).

Aclisina polygyra McCoy, Donald, 1898, op. cit. p. 71 & pl. iii, fig. 11,
quoted as Loxonema polygyra McCoy on p. 55, and referred with doubt
to Aclisina elongata (Fleming).

74 MRS. JANE LONGSTAFF ON [ vol. Lxxtii,

Holoty pe.—‘Syn. Char. Carb. Foss. Irel.’ pl. iii, fig. 1. Griffith
Collection, National Museum, Dublin.

Locality and horizon.—Cullion, Draperstown. Lower part
of the Carboniferous Limestone.

ACLISINA ? SULCATULA (McCoy).

Loxonema sulcatula McCoy, 18-14, ‘ Synopsis of the Characters of the Carbon-
iferous Limestone Fossils of Ireland’ p. 30 & pl. v, fig. 6.
Aclisina ? suleatula Donald, 1898, Q. J. G. S. vol. liv, p. 64 & pl. v, fig. 3.

Holotype.‘ Syn. Char. Carb. Foss. Irel.’ pl. v, fig. 6, and
Q. J. G. S. vol. liv, pl. v, fig. 8. Griffith Collection, National
Museum, Dublin.

Locality and horizon.—Carrickoughter, Kesh. Probably
high in the “Lower Carboniferous Series.

ACLISINA SUBELONGATA, sp. nov. (PI. VI, fig. 1.)

Diagnosis.—Shell elongated, turriculated, composed of more
than ten whorls. Whorls angular, flattened above, shghtly convex
below. Ornamentation consisting of a strong thread on the angle
with one above and three below, space immediately above the angle
rather wider than those below, four or five additional very fine
threads on the base. Aperture not well preserved. Columella
nearly straight. Sutures deep.

Remarks.—This species greatly resembles 4. elongata (Flem-
ing), but the spiral angle is rather wider, the whorls are more
angular, and the threads ornamenting the spire fewer and coarser.

Holotype.—Pl. VI, fig. 1. Though small this specimen is
almost entire. Length=4°25 millimetres ; width=1:25 mm. In
Mr. John Smith’s collection.

Locality and horizon.—Moss Mullock, Kilwinning, in the
Upper Limestone Series.

There is another example from this locality in the same collee-
tion, as well as one from Glencart, Dalry, also in the Upper
Limestone Series. The Young Collection, Kelvingrove Museum,
Glasgow, contains two specimens from Glencart, one of which is
bigger, having nine whorls in a length of 8 mm.; both apex and
base are broken. A shell in the Museum of Practical Geology,
London, appears to belong to this species; it is, however, much
larger and is somewhat crushed. The exact locality is not stated,
only ‘ Glasgow’ being given. It has the appearance of specimens
derived from the Lower Limestone Series, where they frequently
attain a greater size than those from the Upper Limestone Series.
Its length = 14 millimetres for seven whorls, the greatest width of
which =5°5 mm.

ACLISINA ELEGANTULA Donald. (Pl. VI, fig. 2.)
Aclisina elegantula Donald, 1898, op. cit. p. 62 & pl. iv, figs. 138, 13 a—13 ec.

Remarks.—Besides the specimens previously mentioned from
Law, Dalry, and Cunninghambaidland (Ayrshire), Mr. Smith’s

ee a

| part 2] ACLISINA AND ACLISOIDES, 75
collection contains some from Dykes, Kilbirnie, one of which has
the protoconch well preserved. A new drawing (PI. VI, fig. 2) of
the protoconch of the original example is given, as the figure 13 4
does not show that it slightly overhangs the spire. With the
exception of the holotype most of the specimens found are small,
and if it were not for the existence of a shell of intermediate size,
these small examples might be considered to constitute a distinct
species. . ar

Holotype.—Op. cit. pl. iv, fig. 18. Collection of Mr. John
Smith.

Locality and horizon.—Law, Dalry, in the Lower Lime-
stone Series.

The medium-sized specimen is from the same locality, and is in
the same collection,

ACLISINA PARVULA Donald.
Aclisina parvula Donald, 1898, op. cit. p. 64 & pl. v, fig. 1, ? fig. 2.

Remarks.—A. parvula differs from A. pusilla by its more
convex whorls, deeper sutures, and greater spiral angle. There are
two additional specimens in the collections of Mr. Bennie and
Mr. Smith, which occurred respectively at Law, Dalry, and Dykes,
Kilbirnie, in the Lower Limestone Series. I feel doubtful about
the specimen represented by fig. 2 being really this species, and |
think that it is most probably an immature example of A. pusilla.

Holotype.—Op. cit. pl. v, fig. 1. Longstaff Collection.

Loeality and horizon.—Crawfield Quarry, Beith (Ayrshire ),
in the Lower Limestone Series.

ACLISINA TEREBRA Donald.
Aclisina terebra Donald, 1898, op. cit. p. 63 & pl. iv, fig. 16.

Holotype.—Op. cit. pl. iv, fig. 16. Young Collection, Kelvin-
grove Museum, Glasgow.

Locality and horizon.—Crawfield Quarry, Beith, in the
Lower Limestone Series.

There is another specimen in my own collection from Law,
Dalry, also in the Lower Limestone Series.

ACLISINA stRIATISSIMA Donald. (PI. VI, figs. 3 & 4.)

Aclisina quadrata var. striatissima Donald, 1898, op. cit. p. 61 & pl. iv,
fig. 12

Remarks.—lI consider that this form should be regarded as a
distinct species rather than as a variety of A. guadrata. Unfortu-
nately, the shell originally figured has perished with the Hunter-
Selkirk Collection. I therefore suggest as holotype the specimen
mentioned at that time as having been presented to me by
Dr. John Young, from the same locality. It is broken, and only
six whorls remain, which = 3°25 millimetres in length, and not
quite 1 mm. in width. The surface is well preserved, and shows
the ornamenting striz distinctly. I figure now the protoconch

Q. J. G.S. No. 290. Hl

76 MRS. JANE LONGSTAFF ON [ vol. lxxin,

(Pl. VI, fig. 4) of another small example, also given to me by
Dr. John Young, as it is slightly flatter than that of the shell
originally figured. Besides the specimens formerly mentioned,
Mr. J. Smith has four from the Lower Limestone Series of Dykes,
Kilbirnie, and one from the Upper Limestone Series of High
Simithston, Kilwinning. In the Liége Museum I observed a shell
from Visé resembling this in shape and ornamentation, but much
larger: the four lower whorls, which alone are preserved, have a
length of 5-5 millimetres and greatest width of 2°25 mm.

Holotype.—Pl. VI. fig. 3. Longstaff Collection.

Locality and horizonu.—Law, Dalry, in the Lower Limestone
Series.

ACLISINA TENUISTRIATA Donald. (Pl. VI, fig. 5.)

Aclisina tenuistriata Donald, 1898, op. cit. p. 60 & pl. iv, fig. 10.
? Aclisina elongata, vay. cingulata Donald, 1898, pars, op. a p. 55 & pl. 111,
figs. 7 a-7 ¢ [exclude figs. 10 & 10a}.

Remarks.—As this species appears to be rare, it is interesting
to record that Mr. J. Smith has three additional well preserved
specimens, one from Moss Mullock, in the Upper Limestone Series,
one from Craigenglen, and the third from Law, Dalry, in the
Lower Limestone Series. He has also two worn shells, which
probably belong to this species, from the last-named locality. The
example from Moss Mullock has the protoconch intact: it stands
up detached from the post-embryonice whorl, and.is nearly orbicular
in form. ;

Holotype.—Op. cit. pl. iv, fig. 10. Longstaff Collection.

Locality and horizon.—Penton Linns, Liddel Water (Dum-
fries), in the Lower Limestone Series.

ACLISINA GRANTONENSIS Donald.
Aclisina grantonensis Donald, 1898, op. cit. p. 60 & pl. iv, figs. 7-9.

Holoty pe.—Op. eczt. pl. iv, fig. 7. Geological Survey Collection,
Royal Scottish Museum, Edinburgh.

Locality and horizon.—Woodhall, near Edinburgh, in the
Calciferous Sandstone Series. Four specimens in the Kirkby
Collection, Hancock Museum, Newcastle-upon-Tyne, appear to
agree with this species. They are from Randerstone Castle, also in
the Calciferous Sandstone Series.

ACLISINA QUADRATA Donald.
Aclisina quadrata Donald, 1898, op. cit. p. 61 & pl. iv, fig. 11.

Remarks.—Since this is one of the rarer species, it is worth
noting the existence (in Mr. J. Smith’s collection) of a specimen
from the same locality as the holotype, and also of others from
High Smithston and Moss Mullock, Kilwinning, in the Upper
Limestone Series.

Holotype.—Op. cit. pl. iv, fig. 11. Bennie Collection, Royal
Scottish Museum, Edinburgh.

Locality and horizon.—Law, Dalry, in the Lower Limestone
Series.

~“J

ACLISINA AND ACLISOIDES,

AcLISINA actcuLATA Donald. (Pl. VI, tig. 6.)
Aclisina aciculata Donald, 1898, op. cit. p. 59 & pl. iv, figs. 4-6,

Remarks.—Iy addition to the specimens previously recorded,
there are twenty in Mr. John Smith’s collection, six of which have
the protoconch preserved: it is like that figured (op. eit. pl. iv,
figs. Ga—Gc). As the shell in the Hunter-Selkirk Collection, from
which these drawings were made, has been destroyed by fire, it is
especially fortunate that more examples are available. Two of
the specimens not only have the protoconch raised, but the three
higher whorls of the spire are remarkably drawn out and loosely
coiled (Pl. VI, tig. 6). They are all from Dykes, Kilbirnie; that
in the Hunter-Selkirk Collection was from Law, Dalry. Both
localities are in the Lower Limestone Series.

Holotype.—Op. cit. pl. iv, fig. 4. Young Collection, Kelvin-
grove Museum, Glasgow.

Locality and horizon.—Gillfoot, Carluke (Lanarkshire), in
the Upper Limestone Series.

ACLISINA ? MULYIVOLYA, sp. nov. (PI. VI, figs. 7 & 8.)

Diagnosis.—Shell elongated, turriculated, composed of more
than nine gradually increasing whorls. Whorls angular near the
middle, flat or slightly concave above, flat or barely convex below.
Ornamentation consisting of a strong thread on the angle with
three below, the lowest of which is only seen on the body-whor!
and at the suture of the anterior whorls of the spire; above, there
is a strong thread with a finer one close to it, and on one of the
whorls there is an indication of a still tiner thread above. Sutures
deep. Base rather flat. Columella nearly straight. Apex and
aperture unknown.

Remarks.—This species is most like 4. subelongata, but differs
in being more slender, and in having fewer and stronger ornament-
ing threads below the angle, while there is an additional finer one
above.

It is impossible to place the species with certainty, as neither
rotoconch, aperture, nor lines of growth are preserved: it is there-
oa only referred to Aelisina provisionally.

I have met with six specimens, three of which are very small,
and one is also more slender. This last is in the late Dr. John
Young's collection, and occurred in the Upper Limestone Series at
Glencart. The other two belong to Mr. J. Smith, and were also
found in the Upper Limestone Series. The remaining three are of
greater size, otherwise they exhibit similar characters in form and
ornamentation. They are froin the Lower Limestone Series, where
it is not unusual for specimens of much larger dimensions to oceur.
One has seven whorls in a length of 11:5 millimetres, and the
greatest width=45 mm. Originally it must have been more
elongated, for it is compressed upwards, causing the lower whorls
to be broader and shorter. This example is from Bankend (Lanark-
shire). Only the anterior portions of the other two exist, consisting
u2

78 MRS. JANE LONGSTAFF ON [vol. Ixxi,

of five and four whorls respectively. They are from Brockley,
Lesmahagow.

Holotype.—I would select as holotype the smaller of Mr.
Smith’s specimens, as it is best preserved (Pl.*VI, fig. 7). It
consists of seven and a half whorls, the length of which=4°25 milli-
metres and width= 1-25 mm.

Locality.—Moss Mullock.

ACLISINA ASHTONENSIS (Bolton). (Pl. VI, fig. 9.)
Loxonema ashtonense Bolton, 1907, Q. J.G.S. vol. Ixin, p. 464 & pl. xxx,
figs. 17 a-17c¢.

Remarks.—Mr. Bolton kindly lent me the holotype and
numerous other specimens of this species from the same locality.
I found that the lines of growth were discernible on three examples,
and that they indicate ‘the form of aperture characteristic of
Aclisina. A figure of one of these is given in this paper (PL. VI,
fig. 9). On the later whorls there is a certain amount of irregu-
larity in the ornamenting striz, three or four near the middle are
generally stronger than the others, and the spaces between them
are wider, while on the earlier whorls only one of the spaces is
wider; sometimes very fine striz are intercalated between the
coarser striz. This species greatly resembles A. robusta Stevens,!
from the Coal Measures of Danville (Illinois), but it is somewhat
smaller, the upper part of the whorl is flatter, and the lines of
growth are more oblique.

Holotype.—Op. cit. pl. xxx, fig. 17a, Bolton Collection,
Bristol Museum.

Locality and horizon.—Ashton Vale Colliery, in the Base-
‘ment-Beds of the Bristol Coalfield.

Genus Murecntsonta D’Archiac & De Verneuil.
Subgenus AcrisormEs Donald.
ACLISOIDES STRIATULA (De Koninck). (Pl. VI, figs. 10-15.)

Aclisina striatula De Koninck, 1881, ‘ Faane du Caleaire Carbonifére de
Belgique’ pt. iii, Ann. Mus. Roy. Hist. Nat. Belg. vol. vi, p. 86 & pl. ix,
figs. 57-58; and 1883, pt. iv, vol. vil, pl. xxxiil, figs. 41-42, & pl. xxxiv,
figs. 49-51.

Murchisonia striatula De Koninck, 1848, ‘ Description des Animaux Fossiles
du Terrain Carbonifére de Belgique’ p. 415 & pl. x], figs. 7 a-7h.

Murchisonia subsuleata De Koninck, 18438, op. cit. p. 416 & pl. xxxviii,
figs. 4a—-4c.

Aclisoides (Murchisonia) striatula De Koninck, Donald, 1898, Q. J. G.S.
vol. liv, p. 67 & pl. v, figs. 6-8.

Aclisoides striatula, var. armstrongiana Donald, 1898, op. cit. p. 68 & pl. v,
fig. 10 [exclude fig. 9).

Rhabdospira selkirkii Donald, 1898, op. cit. p. 65 & pl. v, fig. 4.

%emarks.—lI have already stated the reason (op. czt. pp. 45, 46)
why this species could not be placed in the genus Aclisina: namely,
the presence of a sinus in the outer lip and a protoconch of different

1 Amer. Journ. Sei. & Arts, vol. ti (1858) p. 259. See also F. B. Meek &
A. H. Worthen, Geol. Surv. Ill. vol. v (1873) p. 596 & pl. xxix, figs. 6 a—6 b.

Feed

ACLISINA AND ACLISOIDES, 79

form. At that time I did not know of the existence of any of the

s of De Koninck’s earlier work (‘ Deser. Anim. Foss. Terr. Carb.
Belg.’ 1543), and founded my remarks on the type selected when
he wrote his later work (‘Faune Cale. Carb. Belg.” 1851 & 1883),
which is in the Musée Royal d’Histoire Naturelle at Brussels, as

well as on similar specimens from the same locality in that and

other collections. I understood him to tell me that all his early
types had gone to America; subsequently, however, I had occasion
to visit the Ecole des Minds: Paris, where through the courtesy of
M. Douvillé I was shown some types which had been presented by
De Koninck in 1846.!. Among them were Murchisonia striatula
(Pl. VI, figs. 10 & 11) and AL subsulcata (Pl. VI, fig. 138). At
first sight they appeared to be distinct species as described, but a
close study of them, as well as of a large series of both Belgian
and British specimens, has convinced me that they are conspecific.
Since De Koninck does not refer to JL subsuleata in his later
work, he may have realized this, though he has not published it.
In the Liége Museum I saw three individuals from Visé un-

-doubtedly conspecific, two of which were marked 4. sfriatula and

the other MW. subsulcata. The type specimens are more or less
distorted by pressure. That of J/. swbsu/cata is rather flattened,
so that, from one point of view the spiral angle appears greater
than it must originaily have been, and this detect is exaggerated
in De Koninck’s figures; the surface is also somewhat worn, there-
fore he describes it as havi ing bands instead of threads and grooves.
The two examples of JZ. striatula are compressed in such a manner
as to make the whorls appear more angular; in one, consisting of
the body and penultimate whorl, this is only slightly so, but in the
other the distortion is greater, so that the sutures are rendered
very oblique and the whorls still more angular; the ornamenting
threads on both are well preserved. The specimen marked as the
type of Aclisina striatula in the Brussels Museum is almost
normal; but it is smaller, and the surface is much worn.

This species exhibits a certain amount of variation, both in form
and in the number and strength of the ornamenting threads. In
some shells the whorls are more exsert, as in two purchased from
De Koninck by the British Museum ( Natural History) G 19984,
which are marked M.‘sfriatula in his own handwriting, in the
specimen described as Rhabdospira selkirkii, and also ina small
example from Hairmyres, Lanarkshire (Pl. V1, fig. 15). In the
greater number of specimens, however, the earlier whorls are closely
coiled and inerease slowly, in such wise that they are lower and
broader than the later whorls: thus these shells are somewhat convex -
in contour, and when immature have a greater spiral angle than
the anterior portion viewed alone has. The holotype of JW. sub-

sulcata and many specimens from Settle have this compact form,

(Pl. VI, tig. 13, & op. evf. pl. v, figs. 6-7), while the two types ot

_ * Annuaire Géol. Univers. 1885, * Musées & Collections Particuliéres, Paris,
Feole des Mines, Coll. de Paléont.’ p. 214. +

80 MRS. JANE LONGSTAFF ON [vol. lxxiil,

MM. striatula, which consist of the later whorls of larger shells, give
the impression of having more slender spires (Pl. VI, figs. 10
& 11). Other individuals are intermediate, such as the Brussels
type (Pl. VI, fig. 12) and some of the specimens from Strathavon,
Lanarkshire.

The type example of JL. swhsulcata is remarkable for showing the
sinus in the outer lip, while the other specimens with one excep-
tion only indicate it by the lines of growth. The sinus does not
give rise to so distinct a band as in ALwrchisonia, sensu stricto,
and is sometimes difficult to discern, being formed of from two to
five threads similar to those ornamenting the rest of the surface.
The position of the sinus is most evident on shells with a slightly
worn surface. The majority of the specimens have fine threads
intercalated between coarser ones, and two of the latter below the
band are generally stronger than the others on the whorls of the
spire.

I consider that the shell described by meas Rhabdospira selkirkii
belongs to this species; it occurred as an external mould in the
Main Lime at Braidwood, Carluke, and has unfortunately been
destroyed by fire in the Hunter-Selkirk Collection, so that it is
now only represented by wax impressions. It is the anterior
portion of a large specimen ; the whorls are high, and show numerous
ornamenting threads. From the markings on the surface I was
led to think that the lines of growth were but slightly sinuated,
and that there was not a distinct sinus. As there is evidence of a
breakage near the aperture, and these markings are only observed
in that vicinity, they are probably adv entitious. The shape of the
shell and disposition of the ornamenting threads greatly resemble
some of the Belgian examples of A. stv riatula, especially the least
crushed one in the Ecole des Mines, Paris.

The specimen designated as the variety armstrongiana (op. cit.
p- 68 & pl. v, fig. 9) must be regarded as a distinct species, and
that represented by fig. 10 as merely a flattened and worn example
of the typical form.

Holotype.—De Koninck did not select any one specimen as
holotype. The two early types in the Ecole des Mines, Paris,
agree very nearly with his specific description ; but the fragment
(Pl. VI, fig. 11), consisting of two whorls alone, accords with the
enlarged drawings, fig. 7 6 of pl. xl, ‘Anim. Foss. Terr. Carb. Belg.,’
and fig. 58 of pl. ix, ‘ Faun. Cale. Carb. Belg.’ It has a length
of 10 millimetres, and its greatest width=7 mm.

The other shell (Pl. VI, “fig 10), consisting of five whorls, does
not accord with either of the figures of a complete shell given in
these works. The length=16 millimetres, and the greatest width
of the penultimate whorl=8°25 mm.

The small worn specimen (PI. VI, tig. 12) in the Royal Brussels
Museum, marked as the type in the later wor k, does not correspond
with any figure, although it belongs to the species. It consists
of e ight whorls in a length of 9°5 millimetres, and has a width of
3-5 mm.

al a a ee i. i eel

part 2] ACLISINA AND ACLISOIDES, 81

The holotype of MW. subsulcata has eight whorls in a length of
18°5 millimetres; its greatest width=6°75 mm., and the depth
of the sinus=about 2°5 mm.

I give new drawings of these shells in Pl. VI, figs. 10-13,
which should be compared with the figures 4, 6, 7,8, & 10, of
pl. v, Q..J. G.S. vol. liv (1898), as well as with figs. 14 & 15,
Pl. VI, of this paper.

- Locality and horizon.—Visé, Assise vi.

This species has previously been stated to occur at Settle! in
England ; at Craigenglen in the Lower Limestone Series, and at
Glencart, Dalry, in the Upper Limestone Series, in Scotland.
Specimens from the English locality greatly resemble in size and
character those from Visé, as do also two from Craigenglen. One
of these last is in the Royal Scottish Museum, Edinburgh; the
other belongs to Mr. J. Smith, and is rather larger and better
preserved : it has eight whorls in a length of 17 millimetres, while
the greatest width=6 mm. The examples from Glencart, like the
other gasteropoda from that locality, are very small.

Mr. Robert Dunlop possesses the best series ‘that I have seen :
it consists of ten specimens which are for the most part large, with
the surface wonderfully well preserved, showing the sinual band,
lines of growth, and ornamenting threads very distinctly. The
latter are especially fine and numerous above the band, while those
forming the band itself vary in number and strength. In one of
the biggest examples (Pl. VI, fig. 14) an old lip-margin is pre-
served, with a deep sinus: it is evidently not the final outer lip of
the adult, as there are impressions of lines of growth on the matrix
showing that the sinus had been filled up, and that part of the
shell-structure had subsequently perished. These specimens were
found a quarter of a mile east of Strathavon, in the Lower Lime-
stone Series.

Besides the small specimen previously mentioned from the Lower
Limestone Series of Hairmyres, Mr. John Smith's collection
contains two minute examples from Brodlie, Dalry, and two others,
also small, from Dernshaw, Stewarton (Ayrshire), from the Upper
Limestone Series. He has also two immature shells from Poolvash
(Isle of Man).

The late Mr. J. G. Goodchild found an external mould in the
Yoredale beds on Widdale Fell, Mosedale ( Yorkshire).

In Belgium this species occurs at Tournai, as well as at Visé. I
possess two specimens from the former locality purchased from

_M. Piret. and there are also two in the British Museum (Natural

History). Prof. L. G. de Koninck merely noted its existence at
Visé.

Altogether | have examined about sixty specimens of this species,
only two of which, both from Craigenglen, have the protoconch
preserved.

' Most of the specimens from this locality are in the Sedgwick Museum,
and were collected by Mr. Burrow; they are merely labelled * Carb. Lst.,
Settle, and the exact locality is not recorded.

82 MRS. JANE LONGSTAFF ON [ vol. lxxiu,

ACLISOIDES ? ARMSTRONGIANA Donald.
Aclisoides striatula, var. armstrongiana Donald, 1898, Q. J. G.S. vol. liv,
pars, p. 68 & pl. v, fig. 9 [exclude fig. 10}. ,

Diagnosis.—Shell elongated, conical, composed of more than
eight whorls. These are slightly angular a little below the middle,
flat above, and convex below. The ornamentation consists of six
threads on the lower two-thirds of the whorl, the three upper of
which are the strongest and suggest a sinual band. Lines of
growth unknown. Sutures deep. Aperture longer than wide;
inner lip reflected on the body-whorl. Columella nearly straight.
Base convex, slightly produced.

Remarks.—I formerly considered this a variety of A. striatula
(De Koninck), but J now believe it to be a distinct species, and
therefore give a fresh diagnosis. It is distinguished from -A. sfria-
tula by its less convex contour, more angular whorls, and deeper
sutures, as well as by the disposition, number, and relative strength
of the ornamenting threads. I can only refer this species to
Aclisoides with a query, as none of the specimens met with have
the protoconch or lnes of growth preserved. It is quite possible
that the discovery of better examples may prove it to belong to
Aclisina.

Holotype.—Op. cit. pl. v, fig. 9. Bennie Collection; Royal
Scottish Museum, Edinburgh.

Dimensions.—Length=10 millimetres; width=3 mm.

Locality and horizon.—Law, Dalry, in the Lower Lime-
stone Series. Besides the holotype there are two smaller specimens
from this locality in the same collection, and Mr. J. Smith has
two examples from Dykes, Kilbirnie, also from the Lower Lime-
stone Series.

EXPLANATION OF PLATES V & VI.
PLATE V.

Fig. 1. Aclisina pulchia De Koninck. Holotype, x 3. Tournai. Brussels
Museum. (See p. 68.)

Figs. 2a & 2b. Aclisina pulchra De Koninck. Fig. 2a. Slightly flattened, x 3.
Fig. 26 Portion of fifth whorl, x12. Tournai. Dorlodot
Collection. :

3a &3b. Aclisina venusta, sp. nov. Fig. 3a xX 5. Fig. 3b Body-
whorl, x 9. Law, Dalry. Bennie Collection, Royal Scottish
Museum, Edinburgh. (See p. 69.)

Fig. 4. Aclisina faber, sp.nov. Back view, X 7°5. (Sée p. 70.)

Figs. 5a—5c. Aclisina faber, sp. nov., juv. Fig. 5a. Front view. x 22°5.
Figs. 5b & 5c. Different views of the protoconch. x 26. High
Smithston, Kilwinning. Collection of Mr. John Smith.

6a-6c¢c. Aclisina delicatiula, sp.nov. Fig. 6a. Back view, X10. Fig.
6b. Aperture, x 15. Fig. 6c. Protoconch, x 26. Longstaff Col-
lection. (See p. 71.)

7a & 7b. Aclisina micula, sp. nov. Fig. 7a. Back view, xX 15. Fig.
7b. Protoconch, X 26. High Smithston. Collection of Mr. John
Smith. (See p. 71.)

Fig. 8. Aclisina similis Donald. Protoconch, x 26. HighSmithston. Col-
lection of Mr. John Smith. (See pp. 71~-72.)

Quart. Journ. Geor. Soc. Vor. LXXIIl, Pr. v.

Bemrose, Collo, Derby»

JL, del.

ACLISINA.

Aa

Quart. Journ. Geor. Soc. Vor. LXXIIl, Pr. Vi.

é

"

Bermrene Cole Derby

ACLISINA ano ACLISOIDES.

ete
_ part 2)
:

ACLISINA AND ACLISOIDES, | 83

Fig. 9. Aclisina pusilla Donald. Protoconch of the holotype, x 26. Law,
Dalry. Collection of Mr. John Smith. (See p. 72.)

10. Aclisina elongata (Fleming). Holotype, xX 14. Lauriston (Brankam
Hall). Ure Collection, Royal Society, Edinburgh. (See p. 72.)

11. Aclisina elongata (Fleming). Front view of a remarkably well-
preserved specimen, X 10. Crawfield Quarry, Beith. Young Col-
lection, Kelvingrove Museum, Glasgow.

12. Aclisina elongata (Fleming). Side view of protoconch, x 26. Dykes,
Kilbirnie. Collection of Mr. John Smith.

Figs. 134 & 13b. Aclisina elongata, var. cingulata Donald. Fig. 134 x 10.
Fig. 13. Portion of whorl enlarged, x 15. Glencart. Young
Collection, Kelvingrove Museum, Glasgow. (See p. 73.)

Fig. 14. Aclisina elongata, var. cingulata Donald. Front view of protoconch,
x 26. Dykes, Kilbirnie. Collection of Mr. J. Smith.

15. Aclisina elongata, var. varians Donald. Back view of protoconch,
x 26. Dykes, Kilbirnie. Collection of Mr. J. Smith. (See p. 73.)

PLATE VI.

Fig. 1. Aclisina subelongata, sp. nov., KX 10. Moss Mullock, Kilwinning.
Collection of Mr. J. Smith. (See p. 74.)
2. Aclisina elegantula Donald. Protoconch, xX 27. Law, Dalry. Bennie
Collection, Royal Scottish Museum, Edinburgh. (See p. 74.)
3. Aclisina striatissima Donald. Front view, xX 16. “Law, Dalry.
Longstaff Collection. (See p. 75.)

4. Aclisina striatissima Donald. Protoconch of another specimen, x 26.
Law, Dalry. Longstaff Collection.

. Aclisina tenuistriata Donald. Protoconch, x 26. High Smithston.

Collection of Mr. J. Smith. (See p. 76.)

. Aclisina aciculata Donald. Front view, X 26. Dykes, Kilbirnie.

Collection of Mr. J. Smith. (See p. 77.)
? Aclisina multivolva, sp. nov., X 10. Moss Mullock. Collection of
Mr. J. Smith. (See p. 77.)

. ? Aclisiua multivolva, sp. nov., KX 10. Glencart, Dalry. Young

Collection, Kelvingrove Museum, Glasgow.

. Aclisina ashtonensis (Bolton). Penultimate whorl of a specimen
showing lines of growth, K 12. Ashton Vale Colliery. Bolton
Collection, Bristol Museum. rer Pi 78.)

10. Aclisoides striatula (De Koninck), x Greatly contorted obliquely.

Visé. One of the type specimens of Murchisonia striatula
De Koninck, in the Ecole des Mines, Paris. (See pp. 78-81.)

11. Aclisoides striatula (De Koninck). Back view of another type speci-
men, X 3. Visé. Ecole des Mines, Paris.

12. Aclisoides striatula (De Koninck). Holotype of Aclisina striatula
De Koninck, * 5. Visé. Musce d'Histoire Naturelle, Brussels.

13. Aclisoides striatula (De Koninck). Holotype of Murchisonia subsul-
cata De Koninck, x 3. Flattened by pressure. Visé. Ecole des
Mines, Paris.

14. Aclisoides striatula (De Koninck), X 3. Showing sinus in old lip-
margin. Spiral angle greater than usual. Strathavon. Collection
of Mr. R. Dunlop, Dunfermline.

15. Aclisoides striatula (De Koninck), X 10. Small specimen with
whorls more exsert than usual. Hairmyres. Collection of
Mr. R. Dunlop.

o ms mf

84. MR. L. M. PARSONS ON THE CARBONIFEROUS _ [ vol. lxxiii,

5. The CarBoNntFERous Limestone bordering the LEICESTER-
SHIRE CoALFIELD. By Leonarp Mites Parsons, D.LC.,
M.Se.(Lond.), F.G.S. (Read March 14th, 1917.)

[Puatres VII-XI.]

CONTENTS,
Page
T.. Introduction 5 5. o0 Ee e ee e 84
It. General Description of the Area .::.....:... .---2.¢\es. see 86
TH. The Western Tnliers 0.0. pds videos ee 87
IV. The Mastern inbers 0.) j 24). axe: Lb iies juste lee 94
V. Comparison with the Main Midland Area ........................ 101
VL. ‘The Origin ‘of the Dolontes:.: 200... 5. 5.2.04..0e20-- <0 104
Vit. Summary of Conclusions -.2/--...c22..-:---. 5 <a 106
Wilt, Palsontological: Notes. |... 2) 25-.mec08 4-00.02 106
TX.. Note.on the Tonge Boring 3y. ...4.d0..21...0-4-. 4 ose

I. Lyrropuctrion.

THE area containing eight inliers of Lower Carboniferous rocks
with which this paper deals is situated north and east of Ashby-
de-la-Zouch. These inliers of Avonian rocks lie within a radius
of 6 miles from Ashby-de-la-Zouch, and the area forms a quadrant
with the line Ashby—Ticknall as the south-to-north radius, and
the line from Ashby passing through Thringstone as the west-to-
east radius.

The westernmost inliers, Ticknall and Calke, are in Derbyshire,
as is also part of the Dimminsdale inlier. The Heath End stream
which flows through the last inlier is there the county boundary.
The eastern side of Dimminsdale and all of the remaining inlers,
from Breedon to Grace Dieu inclusive, are situated in Leicestershire.

The Carboniferous Limestone of the area has been mentioned
but briefly in the Memoirs of the Geological Survey, and the
relations of the Lower Carboniferous to the Millstone Grit have
not been definitely stated.

The original survey of the district was made by Edward Hull,
and his results were published in 1860.1 His map shows a ninth
Carboniferous Limestone inlier situated north of Breedon-on-the-
Hill, and south-east of Melbourne, but no description of it is
given in the Memoir, and it is not shown in maps published more
recently by the Geological Survey.

In the same Memoir (1860) a list of fossils obtained from
Breedon and Breedon Cloud is given; but Hull considered the two
Breedons to be alike stratigraphically, and the names of the fossils
from the two places were put together in the same list, without
any indication as to which Breédon yielded any particular specimen.

‘ «The Geology of the Leicestershire Coalfield’ Mem. Geol. Surv. 1860.

part 2] LIMESTONE OF THE LEICESTERSHIRE COALFIELD. 85
| The Survey Memoir gives two diagrams of importance | pp. 15
: ~ & 17) in connexion with the present paper :—
(i) Sketch of strata seen in the quarry at Grace Dieu. The place is now
so overgrown that the sequefice and relation of the strata are obscured.
(ii) ‘Section across Stanton Harold and Heath End,’ showing the Millstone
Grit conformable with the Shales below.
The district was re-surveyed by C. Fox-Strangways in 1895,
and his restlts were published in the Memoir of 1905,! In this
Memoir is published a list of fossils obtained from three of the

a inliers: namely, Ticknall, Breedon-on-the- Hill, and Breedon Cloud.
: The material from which this list was compiled is for the greater
| part in the collection at Repton School. In addition to the list

of fossils, a few notes of a general character are given concerning
the Carboniferous Limestone.
In a later Memoir? by the same author, the account of the
Lower Carboniferous is much the same as that given in the 1905
Memoir, but at the end of the list of the fossils from Ticknall,
| Breedon, and Breedon Cloud | p. 15], occur the words: ‘The above
| assemblage gives definite indications of the presence of the Dibuno-
: phyllum Zone. Since 1907 nothing has been published concern-
ing the paleontology and zoning of the Carboniferous Limestone
. of the district.
Two factors have made the study of the Carboniferous Lime-
stone north of Ashby a matter of considerable difficulty : (1) The
: old lime-works at 'Ticknall and the exposures in Calke Park have
presented unusual difficulty, as permission to examine them has
always been refused. My own examination of this relatively
small area has been delayed considerably, but Lam pleased to say
that all of the exposures have now been examined.
(2) The inliers farther east, which I have been at liberty to
examine, thanks to the courtesy of Mr. J. G. Shields, of Islay
Walton, are composed of almost barren dolomites. Breedon-on-
| the-Hill and Osgathorpe are particularly barren. Breedon Cloud

is not much better in this respect, but I have received great help
in dealing with the fauna of this inlier from Mr. R. Wood, of
Melbourne, who has placed at my disposal the fine collection of
specimens that he has gradually accumulated in the course of
observations extending over many years.

As a result of correspondence with Mr. R. G. Carruthers,

r Mr. A. R. Horwood, and the late Dr. Arthur Vaughan, | began an
examination of the area during the summer of 1912. Since then
the work has proceeded slowly, on account of the difficulties
encountered.

Although this paper deals more particularly with the faunal
assemblages of the Carboniferous Limestone of the district, certain
questions of petrological interest, such as dolomitization, have
received attention.

' «The Geology of the Country between Derby, Burton-on-Trent, Ashby-de-
’ la-Zouch, & Loughborough ’ Mem. Geol. Sury. 1905,
2 +The Geology of the Leicestershire & South Derbyshire Coalfield’ Mem
Geol. Surv, 1907,

86 MR. L. M. PARSONS ON THE CARBONIFEROUS _ [vol. xxiii,

In expressing my thanks to those geologists who have rendered
me assistance, I must record my indebtedness to the late Dr. Arthur
Vaughan, who examined my collection, identified several specimens,
and encouraged me by helpful criticism and suggestions. Some
months ago he urged me to publish my results at once, but un-
fortunately I was unable to do so, as I had not then examined all
of the exposures in Calke Park. I have great pleasure in acknow-
ledging the continual encouragement and valuable advice received
from Prof. W. W. Watts, whose kind help has enabled me to give
more serious attention to the examination of the Melbourne area
than it was possible for me to do during the years 1912 and 1913.

I am grateful for criticism and advice received from Prof. C. G.
Cullis and Dr. A. Morley Davies. To Mr. R. Wood, of Melbourne,
1 am indebted, not only for the use of his unique collection, but
also for help and companionship i in the field. Several photographs
illustrating this paper are the work of Mr. G. 8S. Sweeting, and I
have received considerable help in the petrological work from
Mr. E. J. Tall. To both of these gentlemen I “offer my sincere
thanks.

Il. GENERAL DESCRIPTION OF THE AREA.

The district being small and possessing relatively simple strue-
tural features, little | need be said under this heading. The general
succession of rocks dealt with is the following :—

(3) Millstone Grit.
(2) Shales.
(1) Carboniferous Limestone.

Apart from the outcrop of pre-Cambrian rocks in the neigh-
bourhood of the village of Thringstone, the oldest formation
exposed in the area defined above is the Carboniferous Limestone,
which crops out in two well-defined series of inliers—a western
series and an eastern series. The area is bounded by unconform-
able Permian and Trias on the north, and in other directions mainly
by two pre-Triassic faults. One of these, known as the Thringstone
Fault, extends from Charnwood in a north-westerly direction to-
wards Repton and brings the Coal Measures down on the south ;
the other, which we may call the Breedon Fault, passes north-west-
wards from Charnwood, and then swings northwards skirting
Barrow Hull, Breedon Cloud, Breedon-on-the-Hill, and King’s
Newton towards the Trent at Swarkestone. The throw of the
Breedon Fault is probably considerable, as a boring through the
Trias near Tonge village reaches Carboniferous Limieseine after
passing through nearly 300 feet of Keuper and about 9 feet of
what is probably Millstone Grit. The Millstone Grit inside the
area is variable in thickness, the Geological Survey estimating that
it varies between 200 and 300 feet. Wherever the junction of
Millstone Grit with the Shales below is seen, there is a conformable
sequence. The lower beds of the former are always conglomeratie,
but the higher portion consists of fine yellowish-white grit, which

part 2) LIMESTONE OF THE LEICESTERSHIRE COALFIELD. S7

is worked in one or two small quarries in the vicinity of Melbourne.
The Shales, which may be looked upon as homotaxial with the
Pendleside Beds, are always sandy for afew feet before they finally
give place to the true Millstone Grit. Their thickness in the area
is very small compared w ith that of the Pendleside Beds in other
districts, a maximum of about 35 feet oceurring in the western
inlier of Ticknall; while farther east at Breedon Cloud, these
shales are probably even thinner, and the boring at Tonge passed
through no beds that can be referred to this formation. Thus,
both the Millstone Grit and the Shales rapidly become attenu-
ated in an easterly direction. ‘The Carboniferous Limestone of
the area has a total thickness of about 900 feet, of which some
$50 feet are seen at Breedon-on-the-Hill, the remaining small
thickness occurring at Ticknall, where the beds carry upwards the
Breedon sequence. The base of the Carboniferous Limestone is

not seen anywhere in the area, although a boring at Desford in the

Whitwick district (9 miles south-east of the Thringstone Fault) has
shown that about 20 feet of limestone there rests on pre-Cambrian
rocks, a description of which has been given by Prof. W. W. Watts
in the Geological Survey Memoir on the Leicestershire & South
Derbyshire Coalfield.

The features of the Eastern and Western series of inliers may
be summarized as follows :-—

The Western Series, including Ticknall, Calke Park, and
Dimminsdale, consist of earthy, dolomitic, and for the most part
highly fossiliferous limestones, exposed along valleys and hollows
by stream-erosion which has removed almost horizontal beds of
Trias and Millstone Grit, showing a small thickness of limestone
and ‘ Pendleside ’ Shales.

The Eastern Series of inliers, including Breedon-on-the Hill,
Breedon Cloud, Barrow Hill, Osgathorpe, and Grace Dieu, are
exposed by earth-movement which has tilted the Carboniferous
Limestone along the Breedon Fault. The material itself is of a
highly dolomitic nature and poorly fossiliferous. ‘ Pendleside’
Shales are only once seen, and the Millstone Grit is never visible.

ILL. Tur Western INicIeERs.

In addition to their mode of exposure and the almost horizontal
lie of the beds already noted, the strata exposed at Ticknall, Calke,
and Dimminsdale have certain characters in common. In all eases
fossiliferous and dolomitie limestones relatively poor in magnesia,
and separated by thin shaly beds, pass upwards into yellow and
grey dolomites having a percentage of magnesia approximating to
that of theoretical dolomite. The lower impure and less dolomitiec
limestones yield an abundant fauna characteristic of a high horizon
in the Dibunophyllum Zone. ‘The dolomites which rest on them.
terminate the Carboniferous Limestone, and the Shales above are
succeeded conformably by Millstone Grit.

The strike of the strata is approximately north and south; but
the dip alters in amount and direction, owing to the occurrence of

$8 CARBONIFEROUS LIMESTONE OF LEICESTER COALFIELD. | vol.]xxiii.

small local faults and gentle rolls. Both Permian and Trias are
uncontormable with the Carboniferous at Ticknall, but the Trias
alone is present at Calke.

Patches of reddish marl seen resting directly upon limestone at
Ticknall must be considered as Drift. The microscopic structwre
of the limestone immediately under this red material shows nome
of the zonal hematite arrangement characteristic of the dolomitize d
limestones seen to underlie the Trias at Breedon and Breedon Clouc}.
Flints obtained from this red material at Ticknall are used in the
renovation of pathways in Calke Park. Remnants of Trias cei -
tainly occur on Millstone Grit at Ticknall, and in Calke Park sout h
of the Abbey. At the extreme north-western edge of the Carbon, -
iferous outcrop at Ticknall a marl (referred by the Geologica |
Survey to the Permian) oversteps the Millstone Grit and Pendlesid, e
Shales, and rests directly upon dolomitic limestone. This maz], ,
which is covered by Trias farther westwards, is worked in a smal 1
brickyard. The exposures occurring in the western inhers ary 2
in general much overgrown, but the old lme-works at Ticknah |
present facilities for a study of the general sequence of strata and
their faunal contents.

The Ticknall Inher,

The road from Melbourne to Repton passes through the village
of Ticknall, where exposures of Carboniferous rocks are seen on
both sides of the road. Those on the northern side, near the
brickyard mentioned above, are much less extensive and more over-
grown than the more recently worked quarries on the southern
side, though sufficient material may be examined to show that the
beds on both sides are of the same lithological type and contain a
similar fauna. The presence of water, ‘which has filled up old
workings, hinders examination on both sides of the road. The dip
generally is towards the west, and its amount varies but is never
very high, an average being about 8°.

Though most of the area on the southern side of the road consists
of a rambling maze of overgrown exposures, disused tunnels, heaps
ot waste aoe | ete., oe are two quarries in connexion where
the sequence can be well seen. The larger of these, which we may
call the Main Quarry, shows recently-worked limestones rich in
Productus (4): this is underlain by hmestones and shales (2-8),
and overlain by dolomites (5), which are in turn followed by

conformable ‘ Pendleside ’ Shales and Millstone Grit. This is the
quarry that can be seen from the roadway leading into the village
from Melbourne. Slightly farther to the south-east is the second
quarry, the workings of which have been prolonged in the form of
caverns; this may “be called the Cavern Quarry. This shows a
similar sequence from (2-5), but crinoidal limestones (1) below (2)
are brought up by a small fault between the two quarries, and the
upper part of (5) has been removed by denudation. The complete
sequence of Carboniferous rocks seen at Ticknall is given in the
section (fig. 1, p. 89) as follows :—

Millstone Grit.

Shales becoming sandy to-

oe

| ings (base not seen). |

|

3

. Thinly - bedded _ lime-

. Sandy stratum.

at Ticknall,

wards the top and passing
conformably into Mill-
stone Grit.

Grey & yellow dolo-
mites,

stones with swarms of |—
Producti and inter- |— _; |

bedded shales.

. Foraminiferal limestones se —— es

is : aS
and shales. a
ME RRS
wees
Crinoidal limestones | cals
with thin shaly part-

’

“Nw

Feet

10

20

40

7¢

——K—eeeee eoeoe eee oe ee

\

es oe
—— = a oe are een,

Fig. 1.—Sequence of Lower Carboniferous strata exposed

S Cavern
/ Exposure

—
~ . ‘ i; : ” .

90 MR. L. M. PARSONS ON THE CARBONIFEROUS _[ vol. Ixxiii,

The total thickness of limestone and ‘dolomite seen at this
locality is about 48 feet. As will be seen from the section, the
‘Cavern’ exposures exhibit beds lower than those at the base of
the ‘ Main’ exposure.

The strata observed at Ticknall are typical of the Western Series
of inliers, and a few comments on the nature of the Ticknall beds
may be given here.

The crinoidal limestones at the base of the Cavern exposure are
mostly thin-bedded, contain a considerable amount of argillaceous
matter, and are separated by thin bands of shale; the bulk of the
rock consists of large unaltered crinoid-stems. Dolomite is absent,
the very small amount of magnesium carbonate present not suffic-
ing for the formation of definite rhombohedra. This point is
discussed in a later section of the paper.

The fine-grained foraminiferal limestones succeeding the crinoid
beds contain hardly any dolomite rhombohedra in their lower part,
but a greater proportion in their upper. The bulk of the rock
consists of impure argillaceous limestone, containing about 8 per
cent. of impurities insoluble in acids. A certain amount of re-
crystallized calcite occurs in place of some original organic
structures.

About 2 feet of a fine-grained sandy material containing Pro-
ductus shells and a little dolomite succeed the foraminiferal lime-
stone just described, indicating an unusually abrupt alteration in
the conditions of sedimentation.

Above the sandy stratum come several feet of thinly-bedded
‘ Productus’ limestones with thin shaly partings. The proportion
of magnesium carbonate is below 12 per cent., and rhombohedra of
dolomite are rare.

Grey and yellow dolomites terminate the Carboniferous Lime-
stone at this locality. So far as I am aware, there is in the
Geological Survey Memoirs no description or even mention of
these dolomites. The beds immediately underneath the shales of
‘Pendleside’ type in the Western inliers consist of about 10 feet
ot almost pure dolomite devoid of fossils. Partings of shale are
not present, as in the lower beds seen here. In the lower part of
the dolomite the higher proportion of limonite gives the body of
the rock a yellow colour, but in the grey dolomite above the iron
compounds present appear to be in the form of carbonate, which
weathering to limonite on the exterior forms a brown crust, and this
gives to the unbroken rock the appearance of a dark grit. In other
respects the yellow and grey dolomites are very similar. No chert
has been found in any of the beds exposed in the Western inliers.

Paleontology of the Ticknall Beds.

In compiling the faunal list my own collection has been the
main source of information, but I have received the loan of speci-
mens from Mr. R. Wood, of Melbourne, Dr. Turton, of Heanor,
and Dr. F. L. Kitchin, of the Geological Survey. Mr. Vassall, of

part 2) LIMESTONE OF THE LEICESTERSHIRE COALFIELD. 91

- Repton, kindly arranged for me to examine the School collection
- ‘specimens mostly collected some years ago ; but, owing to illness

at the time, I was unable to take advantage of his kindness. The
list of species tabulated in the Geological Survey Memoir! was
- based upon this collection, and some of the names, particularly of
corals, have been brought up to date.

FAUNAL List.
[ec = common ; ce = very common ; r= rare ; rr = very rare. |

Corals.
Zaphrentis enniskillent Edwards & Cyathophyllum sp. r.
®. © Lithostrotion junceum (Fleming).
Zaphrentis aff. oystermouthensis ce.
Vaughan. c. Lithostrotion irregulare (Phillips).

pe wnore ef. geniculata Phillips. rr.
Koninckophyllum aff. magnificum
Syringopora cf. reticulata Goldfuss.. (Thomson & Michelin). r.
Lonsdalia floriformis floriformis
Miclites septosa (Fleming). rr. (Martin). rr.
oe derbiense Vaughan. Dibnnophyllum muirheadi. ce.
‘Small indeterminate Clisiophyllids.
“re ef. patula Michelin. r. c.

Brachiopods.

Seminula ambigua (Sowerby). c. | Productus antiquatus Sowerby. c.
Athyris planosulcata (Phillips). e¢.| Productus auritus. ce.
Murtinia glabra (Martin). r. Productus giganteus (Martin). ee.
Martinia lineata (Martin). rr. Productus latissimus Sowerby. ce.
Spirifer bisulcatus Sowerby. c. Productus longispinus Sowerby. c.
Spirifer duplicosta Phillips. r. Productus pugilis Phillips. e.
Spirifer integricosta Phillips. r. | Productus scabriculus (Martin). r.
Spirifer planicosta (M‘Coy). ec. chien uctus semireticulatus (Martin).
Spirifer striatus (Martin), r.
Orthotetes ef. crenistria (Phillips). Pmuabid spinulosus Sowerby. r.
=. <a ef. hardrensis Phillips.
eo" resupinata (Martin). ¢.

L

The following genera and species of corals found in the Lons-
dalia sub-zone of the Carboniferous Limestone of the Derbyshire
area, have not been found :—

Lonsdalia duplicata (Martin). Lithostrotion aff. m‘coyanum
Cyathophyllum regium Phillips. Edwards & Haime.
Dibunophyllum matlockense Sibly. Lithostrotion flemingi M‘Coy.
Dibunophyllum derbiense Sibly. Michelinia glomerata M‘Coy.
Lithostrotion martini Edwards & Aulophyllum sp.

Haime.

The general faunal assemblage leaves no doubt that the fossili-
ferous beds of Ticknall are equivalent to the higher beds of the
_ Carboniferous Limestone sequence of the Midland Province. It is
_ probable that the Ticknall beds are of D,-D, age.

3 - 1) * Leicestershire & South Derbyshire Coalfield’ 1907
Q.I.G.S. No. 290. i

J2 MR. L. M. PARSONS ON THE CARBONIFEROUS [ vol. Ixxiu,

A feature of special interest is the occurrence of a Caninia
related to Caninia patula of the South-Western Province. In
the faunal list I have named this coral Caninia cf. patula, anda
brief description of it is given in the paleontological notes ; but,
acting on the late Dr. Vaughan’s advice, I am classifying, in a
separate paper, the patulid Caninias under a new generic name.
Attention was drawn to the position of the patula division by
Dr. Vaughan in the paper on the Burrington-Combe sequence.!
The ‘cf. Caninia cylindrica’ mentioned in the Geological Survey
list possibly refers to this patulid form, the true Caninia
cylindrica being absent from all parts of the district.

All of the Ticknall limestone-beds below the barren dolomite
yleld Zaphrentis enniskilleni, and it is highly probable that the
crinoidal limestones at the base of the Cavern Quarry are roughly
equivalent to the highest beds on the western side of Breedon-on-
the-Hill, where strata consisting originally of highly encrinital
limestones have been dolomitized.

In the limestones (2), foraminifera are plentiful, including
Endothyra, Valvulina, and several other genera.” Zaphrentis
enniskillent and other corals, particularly Lithostrotion junceum,
occur in these beds; but the brachiopod Produwetus does not occur ©
in such numbers as it does in higher strata. The genus Productus
occurs in all of the fossiliferous strata, including the sandy bed ;.
but it is in the hmestones (4) that the Producti occur in great
numbers. ‘The species massed together in this way are chiefly
variants of the so-called ‘ Productus giganteus’ including such
forms as P. giganteus proper, P. auritus, and latissimoid Pro-
ductus, all of which are very abundant. Other fairly common
species are P. pugilis, P. concinnus, P. antiquatus, and P. longi-
spinus. P. cf. semireticulatus and P. scabriculus are compara-
tively rare. Chonetes cf. hardrensis is fairly abundant, but
papilionaceous Chonetes are extremely rare.

The Calke Inlier.

A few small exposures of Carboniferous Limestone and ‘ Pendle-
- side’ Shales occur in Calke. Park, a short distance south-east
of Ticknall; but the passage of one formation into the other is not
seen. The only exposures of the Limestone sequence are along
the course of a small stream, which flows eastwards to join that
flowing through Dimminsdale. Some small exposures of shale are
seen on the eastern edge of the park, near the junction of the two
streams.

The thickness of limestone seen is very small. At two localities
the exposures display a thickness of several feet. One of these

1S. H. Reynolds & A. Vaughan, ‘Faunal & Lithological Sequence in the
Carboniferous Limestone Series (Avonian) of Burrington Combe (Somerset) ’
Q. J. G. S. vol. xvii (1911) p. 374.

2 EB. Wilson, ‘On the Occurrence of Foraminifera in the Carboniferous
Limestone of Derbyshire ’ Midland Naturalist, vol. iii (1880) p. 221.

part 2] LIMESTONE OF THE LEICESTERSHIRE COALFIELD. 93

places (A in Pl. XI) corresponds to the position indicated by the
words ‘limestone with productus’ on the 6-inch Map deposited
by the late C. Fox-Strangways at the offices of the Geological
Survey; while the other place (B) is the site of the ‘old quarry
shown on the same map. At both places the limestone is argil-
laceous, but that at A is more dolomitie than that at B. The
general dip of the beds seen in the park is about 6° a little south
of east.

The beds of A are slightly higher than those at B. The
microscopic characters of the limestone of A (see Pl. X, fig. 3)
indicate a rock composed mainly of organic remains—corals, small
brachiopods, and foraminifera. A fair amount of recrystallized
calcite is present, and occasional rhombohedra of dolomite. These

: rhombohedra are quite idiomorphic and contain limonite, but there
’ is no zonal arrangement of inclusions. The proportion of mag-
1 nesium carbonate is about 12 per cent. Fossils are not particularly
. abundant, variants of Productus gigante us, such as P. auritus
| and P. antiquatus, being the characteristic brachiopods.

Corals are rare, and I was unable to find any specimens except

Lithostrotion junceum. These beds are evidently the equivalent
of the foraminiferal limestones found towards the bottom of the
beds exposed in the Main Quarry at Ticknall. The immediately
; succeeding strata are obscured by vegetation, but some feet higher
| a yellow dolomite similar in grain to that of Ticknall occurs.
Along the northern side of the stream the ground is much over-
grown, and I found no evidence concerning the unconformity of
the Millstone Grit shown ‘on the Geological Survey map. At the
present time the exposures show limestones alone, the Millstone
Grit being visible only on higher ground farther north, and the
intervening land is overgrown. The old quarries on the south
exhibit grit only. It is to be regretted that the examination of
the Calke exposures is a matter of great difficulty ; and this fact,

together with the overgrown nature of the ground, now makes it
impossible to see the exact relation of the Millstone Grit to the
underlying beds.

The Dimminsdale Inlier.

A little to the south-east of Calke Park the Carboniferous
Limestone and succeeding Shales crop out in a north-and-south
valley traversed by the largest stream in the district. The Lime-
; stone is shown in old workings that are now flooded to the level of
the upper dolomite, the limestones below being inaccessible. About

: 35 feet of shales are seen, conformable with “the lunestone below,
t and passing up gradually and conformably into Millstone Grit.
j The gradual passage and conformity are strikingly exhibited at a
place (x on the map, Pl. X1) east of the stream, and overlooking
one of the flooded quarries. Here the ground has fallen in, showing
the rock facing eastwards, northwards, and westwards in turn.

12

94, MR. L. M. PARSONS ON THE CARBONIFEROUS | vol. Ixxiil,

The lower beds wholly composed of shale become interbedded with
thin sandy layers towards the top, and these finally assume the
pebbly character of the lowest part of the Millstone Grit. The
dip of the beds is here about 4° to the south-east.

IV. Tue Eastern INiIERs. .

If we define the Eastern series of inliers as those occurring
against the Breedon Fault, two small inliers—one at King’s Newton
north of Melbourne, where ‘ Pendleside’ Shales are tilted against
the Breedon Fault, and the other at Grace Dieu near Charnwood-—
must be included with the larger masses of Breedon Cloud, etc.,
although they more nearly resemble the rocks of the Western inliers
of Ticknall, ete. The remaining inliers, from Breedon-on-the-Hill
to Osgathorpe, possess many features in common, such as high in-
clination, the dense vellow dolomitic character of the strata, and,
despite their relative barrenness, the presence of a fauna indicating
stratigraphical horizons in the Dibunophyllum Zone.

Breedon-on-the-Hill.

This hill, which forms a landmark for many miles round, is
made up of moderately thick-bedded dolomites, with some thinner
beds in places. No interbedded shaly partings are seen, and the
unconformable cover ot the Trias conceals any ‘ Pendleside’ Shales
that may exist west of the hill. The strike is constant—
about N. 20° E. to 8. 20° W., while the angle of dip varies but
slightly, averaging about 46° westwards. Shght flexures occur
in the middle part of the sequence, but no faulting is apparent,
the inher differmg remarkably in this respect from Breedon Cloud.
The thickness of Carboniferous Limestone at Breedon-on-the-Hill
is about 850 feet—a figure considerably greater than the 500 feet
mentioned in the Geological Survey Memoir, which, however,
does not make it clear whether Breedon-on-the-Hill or Breedon
Cloud is meant. The estimate of 850 feet is based upon measure-
ments in the field guided by faunal evidence, and is confirmed by
observations at Breedon Cloud. The great quarry-face at the
southern end of the hill extends at right angles to the strike, and
thus affords an excellent section. The beds exposed along this
face constitute roughly two-thirds of the total thickness of the
strata forming the inher—the higher beds being covered with grass,
except those at the very top of the sequence which are to be seen
along the western side of the hill.

The whole of the rock exposed consists of dolomites, variable
both in chemical composition and in mineralogical structure. | A
detailed subdivision of the beds, based upon either lithological or
paleontological evidence, has not been found possible; but the
sequence may be considered broadly to consist of four parts the
exact boundaries of which are not very definite. Commencing at

1 «The Geology of the Country between Derby, Burton-on-Trent, Ashby-
de-la-Zouch,.& Loughborough’ Mem. Geol. Surv. 1905, p. 18—Sheet No. 141,

part 2] LIMESTONE OF THE LEICESTERSHIRE COALFIELD. 95

the western side of the hill and working eastwards, we see that
the main subdivisions are as follows, in descending order :—
4. Pink and red dolomite.
3. Yellow dolomites with some chert.
2. Thickly-bedded yellow dolomites with no chert, but yielding
D Productus humerosus. mn et . ;

1 1. Yellow dolomites and dolomitic limestones yielding Lithostrotion

irregulare, Cyathophyllid corals of the C. murchisoni type, ete.
(Base not seen.)
Total thickness =about 850 feet.

Since the exact boundaries of these subdivisions are not clearly
seen, I prefer not to assign definite thicknesses to them; but the
D, portion of the sequence (1 and 2) probably exceeds 500 feet.
The total thickness, which is here greater than that at any other
inlier north of the Leicestershire Coalfield, is such that, apart from
paleontological evidence. it is justifiable to suppose that the lower
beds on the eastern side of the hill must represent some portion of
the D, limestone of the main Midland area.! A special point to
be noted in this connexion is the entire absence of igneous material
on the horizon of the ‘ toadstones’ of Derbyshire. As the lower
portion of the Breedon-Hill limestone is of D, age, it must be
concluded that the area under consideration was beyond the south-
eastern limit of the vulcanicity associated with the Carboniferous
Limestone of the Pennine Chain. Dr. H. H. Bemrose in his
paper on ‘The Toadstones of Derbyshire,’ refers to the thinning-
out of the igneous material in an easterly direction, and draws
attention to the absence of the ‘upper toadstone’ at Crich, only
a few miles east of Matlock.?

D,-D,

Paleontology of Breedou-on-the- Hill.

The comparatively barren nature of the whole of the beds ex-
posed at Breedon is indicated by the fact that hitherto but two
species: namely, Productus humerosus and Syringothyris (?)
cuspidata, have been quoted from this inlier; however, after a
prolonged search, in which every available rock-face was examined,
I have obtained sutticient specimens of corals and brachiopods
to fix the horizon of the uppermost beds with certainty, and to
leave little doubt that the lowest beds belong to the D, sub-zone.

FAUNAL List.

[Subdivisions indicated by numerals corresponding to those in
the succession tabulated above. }

Upper Beds on the western side of the hill.
( Zaphrentis sp. (? enniskilleni Edwards & Haime). r.
=(4) | Beaumontia egertoni Edwards & Haime. rr.
. J Lithostrotion sp... ¥.
(3). \ Diphyphyllum aff. concinnum Lonsdale. — r.
Spirifer planicosta M‘Coy. r.
| Productus antiquatus Sowerby. r.

' See Prof. T. F. Sibly's paper, Q. J. G. S. vol. lxiv (1908) p. 38.
® Ibid. vol. lxiii (1907) p. 266.

96 MR. L. M. PARSONS ON THE CARBONIFEROUS _ [{ vol. Lxxiti,,

‘ Humerosus’ Beds.

Syringopora sp. fr.

— (2) Pugnaz pugnus (Martin). r.

5 pas Productus hwmerosus Sowerby. c.
Productus sp. r.

Lower Beds on the eastern side of the hill.

( Syringopora cf. reticutata Goldfuss. r.
| Syringopora sp. Yr.
Michelinia? r.
= (1). < Iathostrotion irregulare (Phillips). r. °
Cyathophyllum att. murchisoni Edwards & Haime. ec.
s, apparently of Cyathophyllid &
|. Koninckophyllid types.

Beaumontia egertoni, Spirifer planicosta, and Productus
antiquatus obtained from the western side of the hill, indicate
that these beds (4) are correctly referred to the D, ‘sub- -z0ne,
while the presence of Zaphrentis suggests that the horizon is the
same as that of the fossiliferous beds of Ticknall. These strata
consisted originally of highly encrinital material, and I conclude
that they are the eastern extension of the crinoidal limestones seen
in the western inliers. The dolomites with chert (2) are mostly
hidden, as the quarries do not extend far enough westwards to
break into them. Hence a thorough examination is impossible; but:
there is no reason to doubt that they are the same as the dolomites.
with chert seen at Breedon Cloud, where an undoubted D, fauna
is obtained trom them.

The yellow dolomites (2) with Productus humerosus yield that.
species in fair numbers, and it is supposed that these beds are the
local equivalent of the Caldon-Low facies occurring near Water-
houses in the south-western part of the Midland area! As at
Caldon Low, Syringopora is the only coral found in these beds ;
but, on the other hand, Pugnax pugnus, a brachiopod that is not
mentioned as being found in the Caldon-Low beds, oceurs sparingly
at Breedon, and Daviesiella aff. comoides does not appear to be
associated with Productus humerosus. Prof. Sibly refers the
Caldon-Low beds to the D, sub-zone, and the equivalent beds at
Breedon-on-the- Hill are also referable to the same sub-zone, for
they underlie a considerable thickness of cherty dolomites which
are the local representatives of the cherty limestones of the D,
sub-zone in the Midland area. ‘The Caldon-Low facies has been
observed only at the south-western extremity of the Midland area ;
and, if we consider the Carboniferous Limestone outcrops north of
Ashby as a south-eastward extension of that area, it is interesting
to note that the same specialized Productus-humerosus beds occur
also at the extreme south-eastern corner of the Province.

The dolomites (1) below the ‘ humerosus’ beds, and forming the
eastern side of the hill, are rather thickly-bedded and almost barren.
Where the rock is not being worked it weathers with a grey outer

1 T. F. Sibly, Q. J. G. S. vol. Ixiv (1908) p. 44.

’

part 2) LIMESTONE OF THE LEICESTERSHIRE COALFIELD. 97

skin, which sometimes reveals impressions of coral. These impres-
sions are mere surface-markings which are mostly indeterminate,
and although coral structures exist in the rock, they too are so in-
distinct that sections are generally of even less value than the
surface-markings. Undoubted specimens of Cyathophyllum aff.
murchisoni occur in the rock; but the massive bedding and hard-
ness of the dolomite make it almost impossible to extract them.
Other surface-impressions indicate the presence of large single
corals having a complex tabulate area, but it is impossible to refer
them definitely to Dibunophyllum or any other genus.

Good specimens of Lithostrotion irregulare have been found,
and this suggests that the eastern beds are not lower than D,, a
point supported by the total thickness of rock in the inlier, and by
other evidence.

Syringopora occurs particularly in certain beds at the extreme
eastern end, where masses of shells resembling papilionaceous
Chonetes are also found; but a specific determination of these is

not possible.
Breedon Cloud.

A distance of three-quarters of a mile separates the two Breedons.
The quarry-face of the Cloud works extends for a length of about
500 yards, and is very often parallel to the strike: consequently
the section is not so useful as that at Breedon-on-the- Hill.

The Carboniferous Limestone sequence at Breedon Cloud is as
follows :—

3. Thinly-bedded red dolomites with very thin shaly partings.
D,-D,.4 2. Yellow dolomites, apparently of ‘contemporaneous’ origin, and
containing a variable quantity of chert.
Part of { 1. Yellow dolomites yielding Productus humerosus, but containing
D.. no chert.
(Thickness unknown.)

On account of the amount of material removed by quarrying
operations and the presence of many heaps of refuse, ete., an
accurate statement can hardly be made concerning the actual
thickness of the subdivisions. A few points concerning the
divisions enumerated above may be noted here.

The lower, relatively barren, yellow dolomites yielding Productus
humerosus, Cyrtina septosa, and Pugnax pugnus are best seen at
the extreme northern end of the works, where faulting has pro-
duced a certain amount of lateral displacement. The positions
where Pr. humerosus was obtained are indicated on the plan
(fig. 2, p. 98) by the letter H.

These beds are evidently equivalent to the corresponding
humerosus dolomites at Breedon-on-the-Hill. At one other point
towards the southern end of the inlier I obtained the same species
of Productus at the top of the hill, a little distance east of the
large amphitheatral quarry marked B on the plan. In no part of
these beds was any chert found.

The succeeding yellow dolomites form the bulk of the exposed

98 MR. L. M. PARSONS ON THE CARBONIFEROUS [vol. lxxui,

part. of the inlier, and yield a fauna characteristic of horizons that
may be conveniently expressed by the formula D,-D,. Chert
occurs somewhat sparingly, but is seen easily 7m sztw in the various
excavations (marked E,, etc. on the plan) made in the platform
that constitutes the floor of the main quarry.

The beds of this subdivision of the sequence are repeated by
reversed faulting parallel with the strike. The faults responsible
for this repetition are indicated on the plan at C and E.

Fig. 2.

ROUGH PLAN OF
BREEDON CLOUD WORKS

Scale of Yards
I00

Sidings

The dip of the strata varies in degree from 48° to 60°, while the
direction varies from directly south at the southern end of the hill
to north-west near the position D half-way towards the northern
end of the works. Breedon Cloud appears to be the remnant of a
faulted dome, the eastern portion being thrown down by the
pre-Triassic Breedon Fault.

Jointing is common, and in many places the direction of the dip
is disguised, particularly in that part of the quarry that lies
immediately north of the southern fault. There are many pockets
filled with loose ‘dolomitic sand’ derived from the disintegraticn
of the yellow dolomite, or from the thin overlying red dolomites.

Overlying the yellow dolomites are a few feet of thinly-bedded

—— lh

part 2] LIMESTONE OF THE LEICESTERSHIRE COALFIELD. 99

red dolomites which have yielded Zaphrentis enniskillent and
Diphyphyllum aff. concinnum. Their faunal contents are generally
similar to that of the red dolomites at the top of the sequence of
Breedon-on-the-Hill. The origin of their dolomitization is
discussed in a later section of this paper. One or two thin bands
of shale interbedded with these red dolomites are also stained a

dark red.
Paleontology of Breedon Cloud.

The exposed portion of Breedon-on-the-Hill consists of relatively
barren D, beds; but at Breedon Cloud the exposures consist
almost wholly of beds yielding a D,-D, fauna. At the latter
locality, however, the thickness of the material capable of being
examined is much reduced, on account of the workings being
generally parallel with the strike.

FAUNAL LIST.

Corals.
Sub- Zaphrentis aff. enniskilleni Ed-| Diph yphyllum near concinnum
Giviaion wards & Haime. r. Lonsdale. Large form.
3 Diphyphyllum concinnwm Lons- |
of table | ‘le ¢
(p. 97). Brachiopods:
Spirifer planicosta (M*Coy). | Productus sp.
Corals.
| Beaumontia egertoni Edwards & | Diphyphyllwn lateseptatum
Haime. ec. | M‘Coy. ce.
Syringopora cf. reticulata Gold- Diphyphyllum concinnum Lons-
fuss. c¢. dale. c.
Syringopora ef. geniculata ‘Diphyphyllum near concinnum
Phillips. ec. Lonsdale, large form. r.
; Alveolites sp. rr. Lithostrotion irregulare (Phillips).
a Campophyllum — derbiense r.
| Vaughan. c. Lithostrotion (Petalawis) port-
a Cyathophyllum sp. °. locki Edwards & Haime. r.
| Pvord Brachiopods.
7 : Dielasma hastata Sowerby. r. Pustula punctata (Phillips). r.
of table Athyris expansa (Phillips). ¢. Pustula pustulosa (Phillips). r.
(p. 97). Martinia glabra (Martin). ¢. Productus giganteus Martin. c.
Martinia lineata (Martin). r. Productus antiquatus Sowerby. ¢.
Martinia ovalis (Phillips). r. Productus auritus. ¢.
Spirifer bisuleatus Sowerby. c¢. Productus latissimus Sowerby. ¢.
Spirifer duplicosta Phillips. r. Productus semireticulatus (Mar-
Spirifer planicosta (M*Coy). ¢. tin). r.
Spirifer trigonalis (Martin). r. Productus plicatilis (Sowerby). r.
Pugnaw acuminatus (Martin). r. Productus undatus Defrance. r.
Leptwena analoga (Phillips). ¢. Productus striatus (Fischer), r.
Orthotetes cf. crenistria (Phillips). Productus scabriculus (Martin). r.
r. Orbiculoidea ef. craigi Davidson.
Schizophoria resupinata (Martin). — r.
on
Sub-
division {Bet humerosus Sowerby. Pugnax pugnus (Martin).
D,. ; aes
1 Cyrtina septosa (Phillips).
of table.

100 MR. L. M. PARSONS ON THE CARBONIFEROUS [Vol. lxxiii,

The paleontological material available is very poor, both in
quantity and in state of preservation, compared with that usually
obtained from normal undolomitized limestones of the Lonsdalia
sub-zone. The compilation of the faunal list has only been possible
through the kind co-operation of Mr. R. Wood, whose collection
and help have always been at my disposal.

Coral structures have been preserved by dolomitic replacement,
but all brachiopods occur as dolomite casts. Large single corals
are usually represented by imperfect specimens of which the
internal tabulate area has been removed; hence definite genera
cannot be identified, though several may be present. In these
circumstances it seems better not to make any statement with
reference to genera or species that appear to be absent.

Barrow Hill.

South-south-east of Breedon Cloud, and ata distance of less than
a mile from it, a small exposure of dolomite occurs in a disused
quarry. Formerly the rock was worked for lime, but the place is
now rather overgrown. The quarry faces all directions in turn.
The beds on the northern side dip north-eastwards, but at the
southern end the dip is south-westward on account of a fault.
The rock consists of a dense yellow dolomite very similar to the
denser, poorly idiomorphic, and purer dolomite of Breedon-on-
the-Hill and Breedon Cloud. No deep-red hematite inclusions are
present, although particles of insoluble matter or unaltered calcite
give a cloudy appearance to the crystals. A little lmonite is
present. So far as I am aware, no fossils have been recorded from
this inher. Most specimens observed or collected by me were in a
bad state of preservation, but the following may be quoted :—

Cyathophyllum (2? regium). Athyris sp.

Tithostrotion irregulare (Phillips). Pugnax pugnus (Martin).

Spirifer bisulcatus Sowerby. Productus sp.
Osgathorpe.

Very small exposures occur on both sides of the stream and road.
Only a few feet of dense yellow dolomite exhibiting slight flexures
are seen, and I was unable to obtain any fossils.

Grace Dieu.

The southernmost inlier of the district is situated quite close to
Charnwood Forest, and about 2+ miles south-east of Breedon Cloud.
The exposures are very small and particularly barren. About
24 feet of dark impure limestones, quite unlike the Breedon
yellow dolomite, somewhat thinly bedded and separated by thin
bands of shale, constitute all that is to be seen. Numerous pockets
in the limestone are filled with a brownish marl. The dip 1s about
10° northwards, and the limestone is faulted against the pre-
Cambrian on the south. The only fossil that I obtained was .a

part 2] LIMESTONE OF THE LEICESTERSHIRE COALFIELD. 101

Spirifer of doubtful species. Some time ago Prof. E. J. Garwood
found a species of Productus, which he informed me_ was
sutlicient to fix the horizon as being fairly high up in the Dibuno-
hyllum Zone, but unfortunately the specimen has been mislaid.
t has been considered that the beds at Grace Dieu represent a
higher horizon than that of any part of Breedon Cloud ; but this
cannot be the case, since the beds at the latter place range from
the top of the ‘humerosus’ facies in D, to the ‘Pendleside’ Shales.

VY. COMPARISON OF THE CARBONIFEROUS LIMESTONE OF THE
AREA With THAT OF THE Mary Dtisrricr (DERBYSHIRE
AND Norru STAFFORDSHIRE) OF THE MIDLAND PROVINCE.

A perusal of the lists of fossils tabulated in this paper, and those
given in Prof. T. F. Sibly’s paper on ‘The Faunal Succession in
the Carboniferous Limestone of the Midland Area,’! will show
that, as one might expect, the Carboniferous Limestone north of
the Leicestershire Coalfield is an eastern extension of the Midland
Province. In other words, the faunal sequence exhibited in the
inliers described above is essentially Midland in type.

A comparison of the Midland faunal succession with that of other
Provinces is given in Prof. Sibly’s paper and need not be re-
peated here. I propose only to comment on the relation of the
Leicestershire area to that investigated by Prof. Sibly. In
neither area is the base of the limestone seen.

1. D,, the sub-zone of Dibunophyllum @.

The upper limit of the sub-zone occurs a little above the Upper
Toadstone in Derbyshire, but is indistinct in Leicestershire. The
development in the south-western part of the main area of an
abnormal facies known as the ‘Caldon-Low Facies,’ finds its
parallel at Breedon and Breedon Cloud, and I consider this portion
to be the highest part of D, definitely recognizable in the Leicester-
shire area. Its similarity to the corresponding beds at Caldon
Low has already been noted in the description of the Eastern
inliers. The remaining portion of the sub-zone below the Pro-
ductus-humerosus beds must represent a corresponding thickness
of the same sub-zone in Derbyshire. The fact that simple Dibuno-
phyllids have not been found at Breedon can hardly be considered
of value, as dolomitization has rendered it very difficult to identify
such corals as do oceur. Even the Derbyshire normal limestones
are poorly fossiliferous, and Dibunophyllum occurs there but rarely
in the lower portions of D,. The typical form of Pr oductus
giganteus does not occur in this sub-zone in either district, but
Productus aft. giganteus does occur.

1 Q. J. G. S. vol. lxiv (1908) pp. 42 et seqq.

102 MR. L. M. PARSONS ON THE CARBONIFEROUS _ [ vol. lxxiu,

2. Dy, the sub-zone of Lonsdalia floriformis.

The following characters of the Leicestershire fauna illustrate
general similarities of this sub-zone in the two districts :—The
presence of Campophyllum derbiense, Cyathophyllum regium,
Lithostrotion irregulare, L. portlocki, Zaphrentids in the upper-
most beds, the great number of variants of Productus giganteus,

Fig. 3.

Watérhouses
c

« Ashbourne

Sketch-map
showing the topographical position
of the Leicestershire Area
relative to
the Waterhouses Development

-“Breedon Fault

Ke
> ,am

Scale of Miles
$

°o 10

the occurrence of scabriculate and punctate Producti besides repre-
sentatives of the Martinia group (particularly JZ. glabra), and
the occurrence of Spirifer bisulcatus and Spirifer planicosta.
In the following respects the fauna in Leicestershire differs from
that of Derbyshire :—Lithostrotion junceum occurs in Leicester-
shire only in the upper beds as at Ticknall, and other species such
as L. martini, L. aff. m‘coyanum, and L. flemingi are apparently
absent. Dibunophylla of an advanced type are not commonly
found: D. matlockense, common in Derbyshire, being unrecorded
from any of the inliers that I have described. D. derbiense is
also absent, but D. muirheadi, a species that does not figure in
Prof. Sibly’s faunal lists, is of limited occurrence at Ticknall. In
comparing the coral faunas of the two districts due allowance

part 2] LIMESTONE OF THE LEICESTERSHIRE COALFIELD. 103

must be made for the difficulty experienced in obtaining reliable
specimens from the dolomites; but, even if this allowance be made,
the coral fauna of the Lonsdalia sub-zone cannot be described as
rich. The brachiopod fauna of D, in the two districts appears to
be very similar; but some species, such as Orthotetes cf. crenistria,
and papilionaceous Chonefes, are rarer in the Leicestershire district
than they are in the other. Prof. Sibly distinguished certain
variations in the faunal facies of the Lonsdalia sub-zone in the
Derbyshire district—a general typical facies developed on the
eastern side of the region, and a more or less local south-western
facies with a poor coral fauna. The typical eastern facies includes
Lonsdalia floriformis, Lithostrotion junceum, Alveolites septosa,
and certain Clisiophyllids, none of which is present in the south-
western facies. In the typical development, moreover, the brachio-
pods do not predominate over the coral fauna. In the south-
western area near Waterhouses, the brachiopod fauna is richer
than the coral fauna, and the species of Lonsdalia, Lithostrotion,
and Alveolites mentioned above are absent, as are the Clisio-
phyllids Histiophyllum, Rhodophyllum, ete.

Both corals and brachiopods in the Leicestershire fauna show
that it is with the Derbyshire south-western facies that corre-
spondence is closest. Thus, in the Leicestershire area, Alveolites
septosa has been found only at Ticknall, and there it is extremely
rare; of Lonsdalia floriformis only one specimen has been found
at Ticknall, and it is absent from other localities; Lithostrotion
junceum oceurs at Ticknall only, and there in beds that are at
the top of the Leicestershire D,—-D, sequence. Hist/ophyllum,
ete., probably do not occur, although the imperfect condition of
coral specimens must be borne in mind.

With regard to the evidence available from brachiopods, the
beds at Breedon Cloud certainly yield more of these than of
corals. Not only, therefore, does D, (especially the humerosus
beds) of the Leicestershire area resemble in facies that developed
in the south-western part of the area examined by Prof. Sibly,
but the resemblance is also strikingly marked in the sub-zone

of D,,.

3. D,, the sub-zone of Cyathaxonia rushiana.

In Leicestershire no typical development of the D, sub-zone
exists, and Cyathaxonia itself has not been recorded from {the
area,

In the absence of the index fossil, the abundance of species
common to D, and D, suggests that the beds yielding this fauna
should be designated by the symbol D,—D,,.

A Comparison of Lithological Features.

The chief lithological differences and similarities of the Midland
sequence and that of Leicestershire may be shown conveniently in
tabular form :—

104 MR. L. M. PARSONS ON THE CARBONIFEROUS [vol. Ixxiil,

| ee d |
. Main Midland Area. _ Leicestershire.

Typical Eastern South-Western |

District. District.
De ——_———————.
| Cyathaxonia Limestone and black Limestones and No typical
| vrushiana. shales. shales. Chert development.
Thinly-bedded dark in the lime- Thinly-bedded)
limestones and stones. dolomites
shales with chert. succeeding |
— —_—_____———— moderately
Mainly thinly-bedded Variable lime- thick beds | =
D limestones with stones, dark of yellow )
pee Te chert. shaly partings, dolomite la
itis Thickly-bedded and some chert. with a |
ie ; white limestones variable |
in the lower part. quantity of |
chert. o
Upper Toadstone. Massive white or Fairly thickly- |
Thin dark lime- grey limestones bedded yellow |
| stones. poorly fossili- dolomites.
D;; Thickly-bedded ferous. No igneous
Dibunophyllum white limestones.- material.
0. Lower Toadstone. /
Massive white
limestone.

VI. THE ORIGIN OF THE DOLOMITES.

The dolomites of the Leicestershire area exhibit characters
indicating two distinct sources of origin which are believed to be
referable to (1) the influence of salts in waters of pre-Triassie age,
probably in the Carboniferous Sea itself, upon rocks that were
deposited as normal organic limestones; and (2) the influence of
waters associated with the Trias upon beds which were seemingly
crinoidal limestones previously undolomitized. .

The dense yell!ow dolomites forming the bulk of the
sequence at Breedon, Breedon Cloud, ete.

The greater portion of the dolomites of the eastern inliers is
composed of yellow material, the chemical composition of which
does not differ greatly from that of a pure dolomite. Analyses of
typical specimens from Breedon yield the following average
percentages :—

Calcium carbonate ............... 58°2
Magnesium carbonate ............ 39°6
Iron compounds .............00-.. bs

0°7

Insoluble residue 25.8 eae

|

=
>
oO
oO

|

‘part 2] LIMESTONE OF THE LEICESTERSHIRE COALFIELD. — 105

The amount of free calcite is always small, as shown by slides
stained with Lemberg’s solution. These dolomites are mostly
of minutely crystalline texture, microscopic slides showing more or
less idiomorphic rhombohedra, the outlines of which are seen more
clearly under a high power (see Pl. X, fig. 5).

Limonite is present interstitially, but there are no zonal inclusions
of hematite characteristic of the red dolomites described below.

Organic structures have been replaced by dolomite, or occur
as dolomitic casts; and it is probable that many fossil structures
have been obliterated altogether. The dolomitiz: ation of these beds
appears to be so complete, “that examination of the fossils and their
matrix shows no ‘selective’ dolomitization.

The yellow and grey dolomites of Ticknall are very similar in
mineralogical structure and chemical composition to the massive
delomites of the eastern inliers, but those at Ticknall are coarser in
grain and quite barren of fossils (see Pl. X, figs. 1 & 2).

In all of these rocks there is a general absence of those features
which usually indicate that the dolomitization is due to the in-
fluence of waters of a post-Carboniferous date, and field evidence
appears to support the view that these dolomites are of the
kind described as ‘contemporaneous’ by some authors. They
eecur in definite beds, do not pass laterally into unaltered lime-
stone, and their conversion into dolomite does not appear to be due
to faulting.

The thinly-bedded red dolomites of Breedon
and Breedon Cloud.

Only in the uppermost beds of Breedon-on-the-Hill, and of
Breedon Cloud is there evidence of dolomitization due to the
influence of the Trias.

The rock is pink or red, and the dolomitization is variable in any
particular stratum. The amount of hematite sometimes exceeds
5 per cent. Microscopic sections show relatively large idio-
morphie crystals, with zonal inclusions of hematite, and having an
almost clear outer zone (see Pl. X, fig. 4).

The only organic structures of common occurrence are crinoid
stems, which remain mostly in an undolomitized condition. Here we
note ‘selective’ dolomitization, in which the matrix is dolomitized
while echinoderm structures remain unaltered. In no case have
I found selective dolomitization, in which the rhombohedra have
developed in organic structures and not in the matrix, as is the case

“jn some vein-dolomites of other localities. But the characteristic

zonal hematite inclusions which are always present, and the patchy
nature of the dolomitization, leave little doubt that these red
dolomites may be considered to be of ‘ subsequent’ origin.

106 MR. L. M. PARSONS ON THE CARBONIFEROUS [vol. Ixxiul,

VII. Summary OF CONCLUSIONS.

In the district immediately north of the Leicestershire Coal-
field :—

1. There is a complete conformable sequence from the Carboni-
ferous Limestone to the Millstone Grit inclusive, although the
thickness of the beds of Pendleside aspect 1s small compared with
that of the same formation in other districts.

2. The base of the Carboniferous Limestone is not seen, but
borings have proved that it rests on pre-Cambrian rocks at Desford,
in the neighbourhood of Charnwood Forest.

3. The total thickness of Carboniferous Limestone seen is about
900 feet, all of it included in the Dibunophyllum Zone, the sub-
zones recognizable being D,, D,, and possibly part of D,.

4, Faunal characters indicate that the Carboniferous Limestone
belongs to the Midland Province, but that it more closely resembles
the non-typical development occurring in the south-western part
of the Main Area of that province. The development is not the
normal facies characteristic of the greater part of Derbyshire, and
the various inliers described in this paper must be regarded as a
south-eastern extension of the Caldon-Low facies so far as D, is
concerned, and of the Waterhouses facies as regards the portion
above D..

5. The normal limestones of the Midland Province are repre-
sented by dolomites due, probably, to shallow-water conditions of
deposit.

6. The great mass of dolomite is of contemporaneous origin,
only certain beds of a high horizon, D,—D,, being dolomitized
subsequently.

VIII. PatzxonrotoGgicaLt Notss.

It was my intention originally to give a detailed account of
certain new species, chiefly of Caninia, Zaphrentis, and Syringo-
pora, m connexion with the present paper; but it will be better to
deal with the matter separately. A few notes, however, are
added to explain one or two items occurring in the faunal lists.

The Ticknall exposures yield a variety of Zaphrentids which
include forms that resemble Zaphrentis oystermouthensis Vaughan,
found associated with Z. enniskillent in beds of D,—D, age in the
Gower district of the South-Western Province.! In the Ticknall
specimens, the following characters indicate the similarity. The
calyx is deep. The fossula is on the concave side, and extends
more than half-way across the diameter of the coral. Great
variation in the length of the major septa is observable, and these
septa are strongly convex towards the fossular break. The tabulz
are strongly depressed in the middle. The above description refers
to adult specimens, which are usually about 4 cm. long. Although
the septa are thickened, this feature does not appear to be quite so
pronounced as in the Gower specimens.

1 E. E. L. Dixon, ‘The Carboniferous Succession in Gower’ Q. J. G.S.
vol. lxvii (1911) p. 553.

part 2] LIMESTONE OF THE LEICESTERSHIRE COALFIELD. 107

oT
—Canryta ef. patuta Michelin. (Fig. 4 & PI. X, fig. 6.)

Dr. Vaughan distinguished two forms of this species in the
Caninia zone of the Carboniferous succession in the Mendip
region.!_ The two forms described are respectively widely septate and
closely septate, the former being the morecommon. In both cases
minor septa are undeveloped, but the major septa extend through
the zone of vesicles to the wall. The specimens obtained from
Ticknall closely resemble C. patula Michelin in most points, but
there is a distinct development of short minor septa. Dr. Vaughan
considered the Ticknall mutation as being a late derivative of a

Fig. 4.—Caninia ef. patula Michelin. Natural size.

[Specimen from which the transverse section shown in P], X, fig. 6,
| has been eut.

widely-septate patulid Caninia. The main features of this late
mutation are :—

The coral rapidly widens, frequently attaining a length of 5 cm,, and
the calyx is very deep. A horizontal section cut through an adult
specimen just below the calyx shows: -

* 1. The major septa continuous through the wide vesicular zone.
2. The thickening of the major septa.

! gs. H. Reynolds & A. Vaughan, * Faunal & Lithological Sequence in the
Carboniferous Limestone Series (Avonian) of Burrington Combe (Somerset) ’
Q. J. G. S. vol. lxvii (1911) p. 375.

Q. J. G.S. No. 290. K

108 MR. L. M. PARSONS ON THE CARBONIFEROUS _ [vol. lxxiii,

3. A well-marked cardinal septum.

4. The development of short minor septa through the zone of
vesicles.

5. The tendency to form an inner wall consisting of ares proceeding
from septum to septum.

A comparison of fig. 2 of the Burrington Combe paper with the
cross-section (Pl. X, fig. 6 of this paper), will indicate the
similarity between the fossule and tabule of the two types,—that
obtained from the Caninia horizon of the Mendip area and that
from the D,—D, beds of Ticknall.

DIPpHYPHYLLUM, near CONCINNUM Lonsdale, large form.

A very large form of Diphyphyllum, measuring 18 mm. across
the calyx, occurs somewhat sparingly at Breedon Cloud. “It is
usually obtained in an incomplete form, the central area being
absent; but Mr. R. Wood has collected one or two specimens in
which the tabule and discontinuous columella are preserved. It
is compound cylindrical usually, though sometimes a polygonal
habit is developed. On account of this latter characteristic and
the absence of the central area, this species has previously been
assigned to Lonsdalia floriformis ; but, owing to the kindness
of Dr. Stanley Smith who examined the material, I am able to
state that no specimen of Lonsdalia oceurs at Breedon Cloud.

The nearest Lithostrotion equivalent to this large form of
Diphyphyllum appears to be L. affine. Specimens of Diphy-
phyllum concinnum with polygonal habit also occur in the highest
beds on the western side of Breedon-on-the- Hill.

SYRINGOPORA GIGANTEA Thomson. |

A large Syringopora, the corallites of which are about 4 mm. in
diameter, has been found at Breedon Cloud. In its general
characters this species approximates to the large form described by
James Thomson in the Proceedings of the Glasgow Philosophical
Society.!. The species is of very rare occurrence in England,
and it is interesting to note that specimens have been found in
Dovedale in the south-western part of the Midland area.

1X. Nove on THE TONGE BoRING.

A boring made at Tonge in Leicestershire yielded results which
appear to indicate that—

(1) The throw of the Breedon Fault may be at least 300 feet ;

(2) The Keuper at that locality is about 279 feet thick;

(3) The Millstone Grit was either poorly developed or much
eroded before the deposition of the Trias ;

(4) The ‘ Pendleside’ Shales died out somewhere between Tonge
and Breedon, so that the Millstone Grit is locally uncon-
formable upon the Carboniferous Limestone.

1 Vol. xiv (1883) p, 329.

Quart. Journ. Geor. Soc. Vor. LXXIII, Pr.Vil.

Bererose Cole

>

Ns

-AVER

XV

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THE

TICKNALL:

Quart. Journ. Geor. Soc. Vor. LXXIII, Pc. Vill.

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Bemros

EXPOSURE.

MAIN

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TICKNALL:

L.M.P, photo

—

Quart. Journ. Geor. Soc. Vor. LXXIII, Pr. IX.

‘ONS NYSHINOS AHL

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Quart. Journ. Geol, Soc. Vol. LXXITI, Pl. XI.

[ Carboniferous Limestone

Index of Zonal! Distribution

Ta D,or D,-3

D, Caldon Low Facies

D, below the Caldon Low
Facies

GMM Areas which have not
yielded a definite fauna

x Approximate position
of Tonge Boring

Ss

south-south-east of Dimminsdale has been left blank.
» other ‘ Millstone Grit’ outcrops. |

Quart. Journ. Geol, Soc. Vol. LXXIII, Pl. XI.

[1 Trias
Permian
5 Coal Measures

Millstone Grit
A Pendleside Shale
[==5] Carboniferous Limestone

(Sze also Index of Zonal.Distribution)
Pre-Cambrian

THE
CARBONIFEROUS LIMESTONE
bordering the
LEICESTERSHIRE COALFIELD

Scale of Miles
1

° 2

Carboniferous Limestone
Index of Zonal Distribution
{nti} D,or D,-3
(22) D, Caldon Low Facies
D, below the Caldon Low

Facies

MM Areas which have not
yielded a definite fauna

X Approximate position
of Tonge Boring

[Owing to an oversight, the belt of ‘ Millstone Grit’ south-south-east of Dimminsdale has been left blank,
It should haye been dotted like the other ‘ Millstone Grit” outcrops.)

yee OAC) Cee Pa.
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(Chitag to us. crete ie
By al venbt

a 2] LIMESTONE OF THE LEICESTERSHIRE COALFIELD. 109
¢ various strata passed through in the boring may be sum-
‘marized briefly as follows :—

Thickness in feet.

py racks with veins of gypsum =Keuper ..................... about 279
Grey sandstones = Millstone Grit ............ about 9
‘Thin grey limestones, with aeak:)

shales and thicker lime- - =Carboniferous Limestone about 82
- stones below. \

f Total depth of boring... 370

EXPLANATION OF PLATES VII-XI.

Puiate VII.

“es coca at Ticknall: the Caverns ; 5=dolomites ; 4=thinly-bedded lime-
stones with Productus; ‘3=sandy stratum; 2=foraminiferal
dolomitic limestones ; 1 = Encrinital limestones and shales.

PuaTe VIII.
he main exposure at Ticknall ; 5==yellow and grey dolomites ; 4, 3, 2 as in

PLATE IX.

_ The southern fault at Breedon Cloud, showing thinly-bedded red dolomite
above thicker yellow dolomites with chert.

’ Prater X,

Fig. 1. Ticknall dolomitic limestone ; calcite stained with Lemberg’s solution.
*< 25 diameters. (See p. 90.)
2. Ticknall grey dolomite. Compare the degree of idiomorphism with
that of fig. 5. X 25 diameters. (See p. 90.)
3. Organic limestone, Calke Park. Idiomorphic rhombohedra of dolomite
containing limonite, not arranged in any particular order. Note
the invasion of organic structures by the rhombohedra of dolomite.
x 20 diameters. (See p. 93.)
4. Dolomite from the upper beds at Breedon-on-the-Hill. Hematite in-
‘elusions arranged zonally, clear outer margins. Dolomite of
Triassic origin. 25 diameters. (See p, 105.)

Dense yellow dolomite, Breedon Cloud. Finer grain than in the
Ticknall dolomite. X 25 diameters. (See p. 105.)

6. Transverse section of Caninia cf. patula Michelin. Natural size.
(See p. 107.)

=

PLATE XI.

ogical map of the Carboniferous Limestone bordering the Leicestershire
Coalfield, on the scale of 1 inch to the mile, or 1 : 63,360,

DIscussION.

_Mr. K. E. L. Dixon, after congratulating the Author and
remarking on the close connexion of the Leicestershire Carbonife-
s Limestone with the Derbyshire and Wrekin developments as
12 Seinst those found in South Wales and Clee Hill, asked the
A thor on what evidence the shales between the highest limestone
and the Millstone Grit were assigned to the Pendleside Series.
K2

110 CARBONIFEROUS LIMESTONE OF LEICESTERSHIRE. [ vol. lxxi,

The latter are characterized by a definite fauna, and probably occupy
a definite position in the Carboniferous System. In view of the
fact that, outside the Leicestershire area, the top of the limestone is
of markedly different horizon in different places, even where it is
succeeded conformably by argillaceous strata or by beds of Millstone-
Grit facies, it is necessary that the term ‘ Pendleside Series’ should
be confined to beds containing its characteristic fauna, otherwise it
will become as meaningless as the term ‘ Millstone Grit.’

As to the origin of certain dolomites described in the paper, he
had found that the corals enclosed in Carboniferous limestones
afforded valuable criteria for judging whether dolomitization was
‘contemporaneous’ or of later origin (the latter including that due
to Triassic infiltration). In ‘ contemporaneous ’ dolomites the coral-
tissue resists dolomitization as compared with the matrix, whereas
in Carboniferous limestones dolomitized later the corals are altered
before the matrix. As the corals exhibited from Breedon were
dolomitized, in preference to their matrix, their alteration must be
of later age. Possibly the bulk of the rock was altered ‘con-
temporaneously, ’ and the process extended, by percolating waters,
to the undolomitized organic remains at 4 later date.

The CHarrMan (Dr. A. SmrrH Woopwarp) referred to the re-
markable state of preservation of the teeth of Elasmobranch fishes
obtained from the shales at Ticknall by the late Edward Wilson,
F.G.S. They added much to our knowledge of these rare fossils.

Sir Henry Howorvrn and Prof. W. W. Warrs also spoke.

The AvrHor thanked the Fellows present for their kind
reception of his paper, and expressed his gratitude to Sir Henry
Howorth and Prof. Watts for their kind remarks. In reply to
Mr. Dixon, he drew attention to evidences of contemporaneous
dolomitization afforded by the bedded nature of the dolomites, the
non-existence of any lateral transition into normal limestones, and
the absence of any apparent connexion between faulting and dolo-
mitization. Fossils obtained from the greater part of the sequence
were completely converted into dolomite.

Although the shales lying between the Carboniferous Limestone
and the Millstone Grit had not yielded a typical Pendleside fauna,
these beds had been designated ‘ Pendleside’ in the paper, in order
to compare their dev elopment with that of the strata which oceupy
a corresponding position in the Carboniferous sequence of Derby-
shire.

6. The Canrponirerous Limestone SERIES on the Souru-
Eastern Marcin of the a Wares Coarrretp. By
Frank Drxey, M.Sc., F.G.S., and Prof. Thomas FRANKLIN

Stary, D.Se., F.G.S., Univ sete College of South Wales &
Monmouthshire, Cardiff. (Read March 28th, 1917.)

'PiLates XII-XVI.]

P CONTENTS.
, Page
So. ee edly on ki ccs se ve ncn d pcp iteces cub sevhaubdsicee 111
Il. Structure and Physical Features of the Outerop ............ 114
oes on tne Doloniitization .................0s0..sscece Wil vanes . 116
IV. General Account of the Succession and its Lateral
EME ehie Coss fo Gtk wdhacdina Ghun pavebesewdances Wee 9
V. Detailed Description of the Succession ...................c00ee 124
(A) Lower Limestone Shales.
(B) Main Limestone. -
emery amd Conclusions ...:...........<..scssovseesesseene ave ROT

I. Inrropwucrion.

Tue outcrop of Carboniferous Limestone which is the subject of
this communication extends trom the valley of the Ewenny River
about 3 miles east of Bridgend (Glamorgan) to the valley of the
Ebbw River at Risca (Monmouth), a distance of about 19 miles
from west-south-west to east-north-east.! It lies on the south-
eastern margin of the South Wales coal-basin, and belongs in its
western portion to the northern limb of the Cardiff-Cowbridge
anticline (see map, fig. 1, p. 112).

The area within which this outerop is ante was mapped by
the officers of H.M. Geological Survey (Dr. A. Strahan, Mr. R. H.
Tiddeman, and Mr. T. C. Cantrill), in the course of the re-survey
of the South Wales Coalfield, and the results were embodied in
the official maps and memoirs.’ The present paper supplements the
deseription of the Carboniferous Limestone Series given in those
publications, in the light of recent researches on the Carboniferous
rocks of this country and Belgium by the late Dr. A. Vaughan
and others.

* As regards the field-work upon which this paper is based, all that portion
of the outcrop which lies west of the river Taff has been investigated by
Mr. Dixey, and the portion east of the Taff by Prof. Sibly. In the absence
of Mr. Dixey on military service, the whole paper has been written by Prof.
Sibly.

® Newport sheet (N.S. l-inch map 249) and ‘The Country around New-
port’ 1899, 2nd ed. 1909; Cardiff sheet (N.S, l-inch map 263) and ‘The
Country around Cardiff’ 1902, 2nd ed. 1912; Bridgend sheet (N.S, 1l-inch
map 261 & 262) and *‘ The Country around Bridgend’ 1904. These Memoirs
will be referred to as the ‘ Newport Memoir,’ the ‘ Cardiff Memoir,’ and the
“Bridgend Memoir,’ respectively.

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The nature and significance of the broad variations shown by
the Carboniferous Limestone Series in the extensive South Wales
outcrops have been admirably defined by Dr. Strahan in the follow-
ing words :—

‘The Carboniferous Limestone Series presented a successton of stages in
development. The fullest development was exhibited in the southernmost
occurrences, as regarded both the sequence and the thickness of zones.
A second stage, showing an incomplete sequence and considerable attenuation,
with indications of near-shore origin, was presented along parts of the margin
of the coalfield. Lastly, in the northernmost occurrences, near Abergavenny
and at Pen-cerig-calch, the series dwindled away to 100 feet or less, while in
Pembrokeshire it was wholly overstepped. The inference followed that the
coast-line ran through Pembrokeshire, and not far north of Abergavenny.’ !

Within the comparatively small extent of outcrop now under
consideration the Carboniferous Limestone Series undergoes a
remarkable change. Here, as in most parts of South Wales, two
lithological divisions are recognized: namely, the Lower Limestone
Shales and the Main Limestone. Not only does the whole series
suffer a notable diminution of thickness when traced north-east-
wards along the outcrop, but simultaneously the Main Limestone
changes in character from a formation composed chiefly of ordinary
erinoidal limestones and oolites into an almost uninterrupted
succession of dolomites.2 The elucidation of this change has been
the object of our investigations.

Little zonal work had preceded our studies in the district. In
the east of the area Mr. E. E..L. Dixon,’ who examined the out-
erop for the purpose of collecting information for the second edition
of the Newport Memoir, recognized the equivalence of the Lower
Limestone Shales to the Cle¢stopora Zone, and noted the presence
of the Seminula Zone in the Taff valley. That geologist further
attributed the absence of the Dibunophyllum Zone in the Taft
valley, and the apparent attenuation of the Seminula Zone farther
east, to unconformable overstep by the Millstone Grit, a conclusion
which is confirmed by additional evidence adduced in this paper.

In the west of the district, a visit to the neighbourhood of
Miskin and Llanharry in 1909 enabled Prof. G. Delépine to
recognize the Zaphrentis, Caninia, Seminula, and Dibunophyllum
Zones in the Main Limestone of that area. Our own observations
accord with those of Prof. Delépine, except as regards his identifi-
eation of the Dihunophyllum Zone: the exposures near Llanharry
whieh he assigns to the subzones D, and D, are referred by us to
the Seminula Zone. The subzone D, is represented in ground

! Q. J. G.S. vol. lxvii (1911) p. 567 (in discussion of the paper by E. E. L.
Dixon & A. Vaughan on ‘ The Carboniferous Succession in Gower’).

2 Newport Memoir, 2nd ed. p. 19; and Bridgend Memoir, p. 6.

5 Newport Memoir, 2nd ed, p. 20.

+ * Note on the Faunal Suecession in the Carboniferous Limestone (A vonian)
near Llantrisant Station in the Bridgend area, South Wales’ Geol. Mag. dec. 5,
vol. viii (1910) pp. 67-70.

-

114 MR. F. DIXEY AND PROF. T. F. SIBLY ON THE [ vol. Ixxin,

immediately north of that examined by Prof. Delépine near Llan-
harry, and also in the outcrop farther west; but D, has not been
recognized anywhere within the district here described.

In our description and interpretation of the lithological succes-
sion, we are guided very largely by Mr. Dixon’s Rese researches
on the Carboniferous Limestone of Gower. The joint paper by -
him and the late Dr. A. Vaughan, dealing with that area, will be
referred to as the ‘Gower paper.’! Several lithological terms
apphed by Mr. Dixon to special rock-types, and defined in the
Gower paper, will be employed.

It would be difficult to exaggerate our indebtedness to the
publications of the Geological Survey : to the maps,” for providing
an invaluable basis for our zonal mapping, and to the memoirs
for much information and guidance. We wish to express our
thanks to Dr. A. Strahan, Director of H.M. Geological Survey, for
permission to examine specimens in the Survey collection, and for
facilitating access to the original field-maps of the district.

Il. SrrucrurE anp PuysicaLt FEATURES OF THE OUTCROP.

On the east, the deep gorge through which the Ebbw River
escapes from the coalfield at Risca marks one extremity of the area
dealt with in th’s paper. At that point the outcrop of the Carbon-
iferous Limestone, followed from the west, has just swung into a
direction a little east of north, to persist in a much attenuated
form along the eastern margin of the coalfield. In the west, near
Ruthin, St. Mary Hill, and Penlline,? the Carboniferous Limestone
disappears beneath a cover of Keuper and Lias, to reappear south
and west of Bridgend, and outside the area now under considera-
tion, in extensive outcrops around St. Bride’s Major and Porthcawl.

The Main Limestone forms an escarpment ridge which, although
much more pronounced in the eastern than in the western part of
the outcrop, remains well-developed as far west as Llansannor.
Three rivers flowing from the coalfield breach this ridge. Named
in order from east to west, these are: the Rhymney, which breaks
through in a deep, narrow valley at Machen, only 2 miles distant
from the Ebbw River at Risca; the Taff, which flows in a notably
steep-sided, narrow gorge (Pl. XIII, fig. 1) between Tafft’s Well
and Tongwynlais; and the Ely, which crosses the limestone in a
much wider, shallower valley at Miskin. Farther west, the river
Dawen rises on the limestone near Llanharry, and flows south-
wards between Llansannor and Penlline to Cowbridge. These
rivers traverse the country with a complete disregard of geological

1 <The Carboniferous Succession in Gower (Glamorganshire)’ Q. J. GS
vol. Ixvii (1911) p. 477

? Particularly the 6-inch maps with geological lines, published in the case
of all sheets which include outcrops of Coal Measures.

* The spelling adopted is that of the latest edition of the l-inch Ordnance
Survey map.

part 2] CARBONIFEROUS LIMESTONE OF 8, WALES COALFIELD. 11

5

structure,! save for the probably significant fact that both the Taff

and the Ely cross the Carboniferous Limestone on lines of dip-
faulting.

The limestone ridge attains an altitude of more than 900 feet
between the Ebbw and the Rhymney, although it is there no
more than a feature on the south-eastern slope of Mynydd Machen
(Pl. XII, fig. 3). Strongly developed all the way from the
Rhymney to the Taff, it rises above 8U0 feet in Cefn-On (Pl. XII,
figs. 1 & 2) and Cefn Carnau. West of the Taff, it remains
sharply defined, with a steep scarp-face, through Garth Wood
(Pi. XILI, fig. 2) as far as Pentyrch; but it dies down at Creigiau,
and in the outcrop west of that place never approaches its eastern
development.

* The striking development of the Main Limestone escarpment in
the eastern part of the district here described results from a remark-
able adjustment of minor drainage-lines to geological structure
in that part of the coalfield margin. ‘Tributaries of the Rhymney
and the Taff, selecting the outcrops of the less resistant bands, such

‘as the Lower Limestone Shales, together with the topmost beds of

the Old Red Sandstone, and the shales which form the lower part
of the Millstone Grit, have entrenched themselves in strike-valleys
along those lines (see map, Pl. XVI, and photographs, Pl. X11,
figs. 1 & 2). Between the Ebbw valley and the Taff valley, the

uartz-conglomerates which lie at the base of the Upper Series of

the Old Red Sandstone have determined a bold escarpment which

runs parallel to the limestone ridge. This is magnificently deve-
loped in Craig Lysfaen, Craig Llanishen, and Coed-y-Wenallt,
between the Rhymney and the Taff. The most notable of the
strike-vaileys mentioned above is Cwm Draethen (Pl. XII, fig. 2),
which separates Craig Lysfaen and Craig Ruperra trom the lime-
stone ridge on the north. In this valley the Draethen brook
(Nant-y-Draethen), rising on the dip-slope of Craig Lystaen,
follows the boundary of the Old Red Sandstone and the Lower
Limestone Shales for about 3 miles, in its rapid descent to the
Rhymney at Draethen. In the upper part of Cwm Draethen, as
in several other portions of the outcrop, the valley is relieved by a
low ridge formed by a group of limestones in the Lower Limestone
Shales. This feature. illustrated in Pl. XII, figs. 1 & 2, is further
described on pp. 125-26.

Within the Main Limestone’ itself, variations of lithology are
often clearly expressed in the surface relief. This is particularly
the case in the outcrop east of the Taff valley, where less resistant
bands in the Main Limestone are frequently marked by depres-
sions. For example, a well-defined dry valley east of Rudry marks
a group of dolomite-mudstones and shales in the middle of the
Main Limestone; and on the eastern side of the Rhymney valley
the lithological difference between the lower half of the Main

' A. Strahan, ‘On the Origin of the River-System of South Wales, « its

Connexion with that of the Severn & the Thames’ Q. J. G. 8. vol. lwiii (1902)
p. 207.

TG |: MR. F. DIXEY AND PROF. 1. F. SIBLY ON THE [ vol. xxiii,

Limestone, consisting of hard crystalline dolomites, and the upper
half, composed mainly of dolomite-mudstone, is clearly reflected in
the form of the ground (Pl. XII, fig. 3).

The prevalent northerly to north-westerly dip of the strata is
seldom interrupted. At Machen, however, a sharp roll brings up
an inlier of Old Red Sandstone, and at Tongwynlais anticlinal and
synclinal rolling of the Lower Limestone Shales results from a
sunilar disturbance. North of Ystradowen, another anticline in-
volves the Lower Limestone Shales and the lower beds of the Main
Limestone: this is one of several minor folds developed in the
westward-pitching ‘nose’ of the Carditt-Cowbridge anticline. On
Mr. T. C. Cantrill’s interpretation of the structure,! the main axis
of the Cardiff—Cowbridge anticline coincides with the faulted antt-
cline of Penlline, and thence passes eastwards a little to the south
of Llansannor, thus traversing the south-western corner of the
area described in this paper.

Faulting of the Carboniferous Limestone is practically confined
to dip-faults, which belong to the well-marked north-north-westerly
fault-system? of the coalfield. These vary from small local frac-
tures to displacements of considerable magnitude, the largest being
the Taft's _W ell Fault, the Creigiau Fault, and the Manian Fault.
Both the Tatf’s-Well Fault, w hich is regarded by Dr. Strahan as a
continuation of the Darenddu Fault of the coaltield,? and the
Creigiau Fault, which involves the Keuper, Rheetic, and Lias,* are
attended by much shattering of the Carboniferous Limestone.

In the area east of the Taff valley, no vestige of Mesozoic
deposits remains on the Carboniferous Limestone, and the outcrop
of the latter is almost wholly free from Glacial drift. West of
the Taff the case is very different: a cover of Trias and Lias
conceals a large part of the Carboniterous Limestone Series imme-
diately west of the Creigiau Fault, and the Keuper oversteps the
northern limit of the Main Limestone almost continuously in the
ground west of Brofiscin. Glacial drift is widespread: it conceals
the Lower Limestone Shales effectually over large tracts, and
covers a great part of the Main Limestone west of the Ely valley.

II]. Nove on tHE DOLOMITIZATION.

Dolomites bulk very largely in the Carboniferous Limestone of
this district, and in the area east of the Taff valley they com-
pose the Main Limestone almost to the exclusion of non-dolomitic
limestones. Both contemporaneous dolomites and vein-dolomites
(subsequent dolomites) are developed extensively, but the former
in much larger amount than the latter.°

1 Bridgend Memoir, pp. 7-8, with sketch-map (fig. 1, p. 8).

2 Newport Memoir, 2nd ed. p. 4. 3 Ibid. pp. Zan, aaa

+ Cardiff Memoir, 2nd ed. pp. 47, 72.

» Methods of distinguishing contemporaneous and subsequent dolomitization

are discussed by Mr. E. E. L. Dixon, in ‘ The Country around Swansea’ Mem.
Geol. Surv. 1907,'pp. 13-20 & pls. i-i.

TS ae, eee

part 2] CARBONIFEROUS LIMESTONE OF 8. WALES COALFIELD. 117

Mr. E. E. L. Dixon pointed out the contemporaneous origin of

_ most of the dolomitization in the outcrop comprised in the Newport

map, which includes the eastern part of our area, and we cannot
do better than quote his words :—

*From the fact that the dolomite is comparable with that of Gower, and
persists as such for upwards of 15 miles, it may be inferred that much of the
dolomitization was ** contemporaneous ’ rather than the result of subsequent
alteration along veins or faults. That the rocks were at first calcitic is shown
by their containing crinoidal remains, and the expression “ contemporaneous ”
is intended as implying dolomitization while they were still under the influence
of the Carboniferous Limestone sea. One of the bands, however, in the
argillaceous group was examined under the microscope, and found to have
been a dolomite-mud, such as might have been derived from the detrition of
dolomites.’ !

Vein-dolomitization, due to a much later metasomatism, is
widespread, being particularly well developed, for example, in the
Seminula Oolite of Creigiau and the Taff valley. Its great
development in the localities mentioned may be attributed to free
eirculation of magnesian waters in highly-fissured limestones
adjacent to large faults, but elsewhere it appears to have resulted
chiefly from diffuse permeation.

Inasmuch as contemporaneous dolomitization was induced by
conditions which accompanied the deposition of the Carboniferous
Limestone, whereas the distribution of vein-dolomitization bears
no relation to those conditions, we have attempted a systematic
discrimination; and the nature of the dolomitization as inferred
by us is expressed by means of conventional signs in the sections
illustrating this paper. Discrimination is often uncertain, how-
ever, and no uniform accuracy is claimed. Moreover, it is pro-
bable that many cases occur in which limestones partly altered by
contemporaneous dolomitization were further affected by vein-
dolomitization at a later date.

TV. GENERAL ACCOUNT OF THE SUCCESSION AND ITS
LATERAL VARIATION.

The Lower Limestone Shales rest conformably upon the Upper
Old Red Sandstone. The Main Limestone is sueceeded uncon-
formably by the Millstone Grit, the base of the latter formation
overstepping from higher to lower horizons-in the Main Limestone
when traced north-eastwards along the outcrop. In general, shales
form the lower member of the Millstone Grit; but locally, in the
east of the district, a quartz-conglomerate is developed at the base
of that formation.

The vertical sections (fig. 2, p. 119) illustrate the general lithology,

' Newport Memoir, 2nd ed. pp. 19-20. Specimen E 7423 in the collection
of the Geological Survey represents the band mentioned in the last sentence
quoted. It is to rocks of this type, largely developed in the sequence east of
the Taff, that the term dolomite-mudstone is applied in this paper.

MR. F. DIXEY AND PROF. T. F. SIBLY ON THE [| vol. lxxin,

118

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posodxo 10}40q oav So[RYG oUOJSoUIT LOMOTT oY OLOYA “YRT, OYF JO ySvo FuoUrdo[orop YF WOTF POLLOFUL WOLFVLITIOL) ¢

‘soyeys puv souoysoury , ('yf)
‘oYITOO pur ouoysounry peprourry (“yy to ‘ yf)
‘SOMOPSOUNT, UIYF YFLA sopegg (“s)

“OSV
+ SOYLULo [Op pues SOUOJFSoOUAyTy] [VprLOmLty)

‘souoqsourry peprourry ('DA)
OPLULOTO(T, VSOWLUWYTT
‘OPTLON VUILUDD

LTT

cosvyd DIOLPOWT
. Q r Sa 4 4
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“OULLOO DYNULUA KY
"SOIMGZOUAYS OLFTLOSTA YYLAr

souoysounry Aq A[petoodso poztaogovrvyo ‘osvyd vjorpopy

*SBIO0OL qopnosd surpnu pout ‘SOUOJSOULL'T

"yy ouo7z, v..0do7s8107)

"7, QUOT, SLpNaLydne

vl nunnEna
) 907, DIWIUDD LOMOTT

‘late ouoy vumuny codd yy

Me OUOIZ, DPILUTULAS ULB]

wal

(qaed ut *q (2) ! auoz7, wnppfiydounquy

‘AMUOZQGUG £0 9U0T

*(LTAV,7 QOVIDINUNAY) HHL 40 Sa ) dOUOLOAO CHL HO LUV NUWMLSH AA AHL NI NOISSHODNG WHEL FO SISTONAG

‘oA ATHE OY} JO JOM VoLR oY} Ut ATUO YUOSeT |

“UBIUOA YW
LO MOTT

‘UVIUOAW
tadd

+ 2] CARBONIFEROUS LIMESTONE OF 8. WALES COALFIELD. 119

a well as the zonal correlation, of the succession at several points
along the outcrop. The accompanying table (p. 118), which

-_ wa 2 woe

—, Fig. 2.

Millstone

VERTICAL SECTIONS of the CARBONIFEROUS LIMESTONE SERIES

— on the
| ere. 9 SOUTH-EASTERN MARGIN of the SOUTH WALES COALFIELD.
peers »D ‘e

Frank Dixey & T.Franklin Sibly.

if
er He

a

Tr

Note.-The numbers used in the Miskin
section are those employed in
the description of the beds in the

4
oy
if

text.

Seminula Oolite

P]
Caninia Oolite 8 Vane ae!

TT ! "189 J7) BE

ce
TT 4

I

A 5 Site Ps

ee ae

Ld
a Contemporaneous
=) I dolomi tion
eel Subsequent or

vein-dolomitization

MISKIN

RUTHIN & TAFF'S WELL
a} non TONGWYNLAIS

‘summarizes the sequence in the western part of the area, where
the development of the Avonian is most nearly complete, em-
bodies the essential features of the Ruthin and Miskin sections of

fig. 2.

-

ee ee —— ee See

Taare) aaoqe joo 00S woryDas JO duT-aseg

torezIy!WOJOp snosuvrodurayu0D FT] THA 5
MOND [Ta] MHz yRWOJop-uyeA 40 quanbasqns [CT] . eb [Bo1}.10A 2 ne phe :
9.1NJ9NI4S 9191100 [TT] ' eo SRS
seeus
suo spues ouo1s Peas 2 OSS Conn ay ULe YP ie
LOMA TD
P°uY PTO cL a) tS 25 Ota

“a
YEZZLZZZL GEE
ZELLD ae Z
Z Ys

= A GIFS

QZ RL
Zz SS
FB

BOR = N=

a

ugo-uwuyas

CHIQay Uayunuy “7) UQ-Ufag JO saruagy auOJsaUMarT SNOLAfMOgLn ay), YbnOLY) WOrZIaS 19] U0ZWOTT —"p “SI

UOTPEZI}IWIOTOP-uraA 10 JUOUbasqus jean yroyy [+ =] arr &
UOTJeZIPIUMIO;OP snoauesr0dutayu07D Al O.MINAYS ITO ESEEE]

199,7 OOor o0oS o
TRON}19A 29 [BJUOZLIOY ‘ayeOS

Partie p | SUO1S OUII I1e
SuoJsoUTT | ° 1 ea | UIBYAL

tee)
SUOISPUBS psy PIO

7 I> zy Y's ZS SUOISTIIP!
3 rs y Z COALS Re ECO OOP LTO RD. CAL O
(LILLE <2, RES LOLI SEE GLEGEAE
ee —— SLI Z 33 oe KE ALAN Ze : pg SE SSS S < }

‘A AUS

ae ee ee

ip ha

+ 2] CARBONIFEROUS LIMESTONE OF 8, WALES COALFIELD. 121

At the western end of the district here dealt with, around
Ruthin, Penlline, and Llansannor, the total thickness of the Car-
boniferous Limestone Series probably approximates to 2750 feet,
made up as follows :—

Feet,
D (Dd, and (7) D, in part) 600
Se Gs Sire eee : .
2) Eee aS Tan
C, +8, Main Limestone
oe 1200
BD ek
ccc e ce kcec-eeseeceesse-vee+- (?)850 Lower Limestone Shales.
Total ee oir, 2756

The thickness here assigned to K is conjectural. The other
figures may be regarded as fair approximations. A cover of Trias
eonceals the junction of the Main Limestone with the Millstone
Grit. D, has not been recognized, and, if represented, it is most
probably incomplete. The Lower Limestone Shales, in so far as
they are exposed, present a normal facies of limestones and shales.
The Main Limestone is composed essentially of undolomitized
erinoidal limestones and oolites, with a standard fauna. The
upper part of S,, however, shows the lagoon-phase deposits which
are so characteristic of that horizon! over most of the South-
Western Province; and contemporaneous dolomitization of the
limestone is important at two levels: (1) in Z, and (2) in C._—the
Laminosa Dolomite. A Modiola phase at the base of C,, detected
at Miskin, about 4 miles away to the east, may be present, but has
not been proved.

At the north-eastern extremity of the area here described, that
is, in the Ebbw valley at Risca, the total thickness is reduced to
about 800 feet, made up as follows :—

of Feet.

675 Main Limestone.

Oe Ree a eee 125 Lower Limestone Shales.

Gcciias.:.sxieq OUD

There the Main Limestone is almost wholly dolomitic. Its lower
portion, about 400 feet thick, consists entirely of crystalline dolo-
mites representing contemporaneously-altered standard limestones,
in which occasional crinoid-ossicles are practically the only
surviving fossils. Its upper portion, about 275 feet thick, is
composed almost wholly of dolomite-mudstones with intercalated
bands of crystalline dolomite, but includes a very small thickness
of calcitic oolite and calcite-mudstone near the summit. In this
upper portion, the dolomitic beds are barren, but the calcitic beds
contain ostracods and foraminifera: this is essentially a thick
Modiola phase, characterized by a great development of dolomite-

1 ®. E. L. Dixon, Gower paper, p. 514,

A RN a a

122 MR. F. DIXEY AND PROF. T.F. SIBLY ON THE [ vol. Ixxi,

mudstone, which ranges from some level in C, up intoS,. The
Lower Limestone Shales of the Ebbw valley, on the other hand,
are unaffected by contemporaneous dolomitization, and present a
normal, fossiliferous character.

Between the Ewenny valley and the Ebbw valley, therefore, the
Dibunophyllum, Beds and the Main Seminula Zone are cut out by
overstep of the Millstone Grit; while the surviving members of the
Main Limestone suffer much attenuation, and change from a mainly
non-dolomitic series of standard limestones into an almost un-
broken succession of crystalline dolomites and dolomite-mudstones.
The Lower Limestone Shales, though also suffering attenuation,
maintain their character substantially unaltered.

In the western part of the district, a well-detined series of zonal
divisions in the Main Limestone can be traced as far east as the
neighbourhood of the Creigiau Fault. But contemporaneous dolo-
mitization increases rapidly in its vertical extent as we proceed
eastwards, and obliterates part of this zonal succession in the out-
crop between the Creigiau Fault and the river Taff. In the Taff
valley, contemporaneous dolomitization has affected almost the
whole of the Main Limestone up to, and including, the basal beds
of 8,; but the bulk of S, has escaped alteration, except for localized
vein-dolomitization. East of the Taff valley the greater part
of §, is soon cut out by overstep. The surviving members of the
Main Limestone remain almost w holly dolpmaaele but in C,,
and again at the base of S,, the formation of doloan= has been
partly due to vein-dolomitization. Dolomitization and the develop-
ment of Jodiola-phase deposits obliterate the faunal succession so
largely that only two zonal horizons can be traced in the Main
Limestone east of the Taff: these are (1) Z,, which can be recog-
nized at a few localities, and (2) the base of S,, a well-marked
horizon which can be traced as far as the Rhymney valley, where
it is overstepped by the Millstone Grit. The Modiola- phase
deposits. essentially dolomite-mudstones with subordinate calcite-
mudstones, become conspicuous in the upper part of the Main
Limestone a little east-of the Taff, and increase in a northi-easterly
direction until, in the ground between the Rhymney and the Ebbw,
they form nearly half of the Main Limestone as there developed.!.

Attenuation of the strata.—Marked attenuation in a
north-easterly direction from the Taff valley is shown by the
Lower Limestone Shales and those divisions of the Main Limestone
which persist. As regards the Lower Limestone Shales, estimates
of thickness west of the Taff are of little value, owing to the
prevalence of drift; but a great reduction of thickness north-east-
wards from the Taff valley, from about 260 feet at Tongwynlais to

1 These constitute an argillaceous group which, as stated in the Newport
Memoir (2nd ed. p. 20) ‘ appears at Risca and runs thence south-westwards....’
It is in consequence of unconformable retrogression of the Millstone Grit, as
the Carboniferous Limestone is traced from the north-east, that the beds in
question make their appearance in the Ebbw valley at Risca.

—

_—< — .*

part 2) CARBONIFEROUS LIMESTONE OF 8. WALES COALFIELD. 123

_-

125 feet at Risca, is indisputable. In the Main Limestone, account
can only be taken of the sequence, Z to 8,, as a whole, because an
accurate delimitation of C, and C, is only possible in the neigh-
bourhood of Miskin: elsewhere west of the ‘Taff, and in the almost
barren dolomitic series east of the Taff, the C.-C, boundary can
only be sketched. The thickness of the series, Z to S., estimated
at 1130 feet near Miskin, probably increases south-west of that
place. Eastwards from Miskin it increases to at least 1250 feet in
the Taff valley, owing to expansion of the C,+8, beds. East of
the Taff, however, where the outcrop of the strata is trending north-
eastwards, it diminishes to 850 feet on Cefn-On, and to between
650 and 700 feet near Machen.

Overstep of the Millstone Grit.—Overstep is very gradual
along most of the outcrop, but it becomes rapid at those points
where the zones of the Carboniferous Limestone swing north-east-
wards,! namely: (1) in the ground west of the Ely, (2) immediately
east of the Taff, and (3) immediately east of the Rhymney.

In the area west of the Creigiau Fault, the junction of Carbon-
iferous Limestone and Millstone Grit is everywhere concealed,
either by Keuper or by Glacial deposits. But the rate of overstep
is undoubtedly rapid in the ground west of the Ely, and slow
east of that river. At Ruthin, the Dibunophyllum-Beds have a
thickness of at least 600 feet; but near Brynsaddler, 4 miles away
to the east, the position of the Millstone-Grit boundary, deduced
from Mr. S$. Vivian's section of the Trecastle iron-mine,? indicates
that only about 100 feet of the Dibunophyllum Zone survives.
On the other hand, overstep does not progress much below the base
of D in the distance of 6 miles between Brynsaddler and the
‘Taff valley.

East of the Taff valley the base of the Millstone Grit can, as
a rule, be traced with considerable accuracy. No actual junction
with the Carboniferous Limestone is, however, exposed.’ Rapid
overstep cuts out at least 300 feet of the 8, beds in a distance of
little more than a mile north-east. of the Tatf valley, and another
sharp transgression takes place immediately east of the Rhymney.
This latter transgression, which carries the Millstone Grit across
the base of 8, and far down into the underlying beds, probably
into C,, coincides with the development of a thick lenticle of
quartz-conglomerate at the base of the Millstone Grit. It leads
to the maximum overstep of the Millstone Grit within
the district here dealt with, ata point midway between the Rhymney

1 The significant trend is, of course, that of the base and zones of the
Carboniferous Limestone. Inasmuch as overstep is causing rapid attenn-
ation of the outcrop of the Carboniferous Limestone at these very points, the
trend of that outcrop as a whole has no significance in this connexion.

2 Trans. S. Wales Inst. Eng. vol. xiv, No. 3 (1885) pl. xxvi. Reproduced in
the Bridgend Memoir, fig. 11, p. 109.

* The junction formerly exposed in a railway-cutting on the western side
of the Ebbw valley (Newport Memoir, 2nd ed. p. 21) is now concealed.

Q. J.G.S. No, 290. L

124 MR. F. DIXEY AND PROF. T. F. SIBLY ON THE [vol. ]xxin,

and the Ebbw rivers. Northwards from that point, towards Risea,
the quartz-conglomerate dies out, and simultaneously the base of
the Millstone Grit retrogresses, uncovering the C,+S, beds on the
western side of the Ebbw valley, but not recrossing the base of S,.
The retrogression is, however, merely a local incident. Immediately
north of the Ebbw river, just outside the limit of the area here
described, the Millstone Grit resumes its overstep on to lower beds
in the Main Limestone.

V. DerralIneD DESCRIPTION OF THE SUCCESSION.

Note in regard to localities. — Important localities
throughout the district have been indicated upon our copies of the
6-inch Ordnance Survey maps by symbols or locality-numbers,
as, for example, A 1, 42. “The complete descriptive symbol for any
locality therefore consists of the number of the appropriate 6-inch
sheet (Glamorgan or Monmouth), followed by the locality-number ;
for example: Glam. 36 SW d4 designates locality 4 in the 6-inch
sheet Glamorgan 86 SW. These descriptive symbols are quoted in
this section of the paper, and a majority of them are marked upon
the maps (Pls. XV & XVI) which illustrate the paper.

(A) Lower Limestone Shales.

As compared with members of the Main Limestone, the beds
constituting the Lower Limestone Shales suffer little change of
character when traced through the district here dealt with. The
only notable variation is an increasing development of shale in
proportion to limestone in the lower beds, when followed from east
to west. But the strata undergo a steady expansion in thickness
south-westwards from the Ebbw valley to the Taff valley, and the
expansion 1s apparently maintained along their outcrop west of the
Taff. Between Risca and Tongwynlais, the thickness of the Lower
Limestone Shales increases from about 125 to 260 feet; near
Miskin it probably exceeds 300 feet, although a partial masking
of the beds by Glacial gravel renders this estimate uncertain ;
farther west, the drift-cover prevents any determination of
thickness.

No section in the district here described exposes the junction of
the Lower Limestone Shales with the Old Red Sandstone, although
a band of calcareous grit which is the lowest bed exposed in a
stream-section below Coed-y-Mochyn, in the Ebbw valley, marks
the approximate, if not the precise, base of the Carboniferous
(fig. 5, p. 127). But there is no reason to doubt the conformable
relation of the two formatians.

East of the Taff, the characters of the Lower Limestone Shales
are well displayed in fairly numerous sections; west of the Taff,
the beds are extensively covered by drift, and exposures are less
satisfactory. The development east of the Taff is, therefore,
described first.

:

East of the Taff.

A twofold division of the Lower Limestone Shales, on lithological
grounds, was established by Dr. A. Strahan in this outerop, and
represented upon the Geological Survey map.!| Our own observa-
tions lead us to recognize three divisions.

Lower Limestone Shales between the Ebbw and the Taff.

——— eee _ -

GEOLOGICAL SURVEY. | PRESENT CLASSIFICATION.

a —

Shales with thin bands 3. Shales with thin K,.—Subzone of Spiriferina
and nodules of lime-— limestones. octoplicata (J. de C. Sow-)
stone. 50 to 100 feet. erby) mut. 6 Vaughan. |

|
a
;

2. Crinoidal limestone
and oolite. K, or K,,.
45 to 100 feet
Crinoidal limestone, | : was

often oolitic. eee ae fo ee es |
(‘Lower Limestone.’) pee

bh: bg pear mpaae and K,.—Subzone of Productus|

. j ) 30 to (2) 60 feet. bassus Vaughan. )

SE ee ee eee

Our lower division (1) consists mainly of limestone in the Ebbw
valley, but includes almost as much shale as limestone in the
Taff valley. A partial establishment of J/odiola-phase conditions
is indicated by several features of this lower group, namely,
seams of calcite-mudstone with Serpu/a, limestones of a-type,? and
limestones with a mixed fauna of crinoids, brachiopods, ostracods,
and thin-shelled lamellibranchs.

The faunas of our lower and upper divisions (1 & 3) warrant
the reference of these two groups to K, and K,, respectively, but
the scanty fauna of the middle group of limestones (2) affords
no grounds for correlation with one subzone rather than the other.
It is interesting to note, in this connexion, that both in Gower
and in Pembrokeshire a band of oolitic limestone affords the best
boundary between K, and k,.*

Along much of the outcrop between the Ebbw and the Taff the
unequal resistance to denudation of the limestones forming the
middle division of the Lower Limestone Shales, and the shales of
the upper division, is strikingly expressed in the surface relief.
The limestones give rise to a low escarpment-ridge, separated from

' Newport Memoir, 2nd ed. p. 19, and Newport sheet.

? That is, limestones consisting essentially of crinoid-ossicles and bryozoa,
broken and rounded by rolling, reddened with hematite, and cemented by
clear granular calcite. On the character and significance of such limestones.
see E. E. L. Dixon, Gower paper, p. 515.

3 E. E. L. Dixon, Gower paper, pp. 497-98, and ‘The Country around
Haverfordwest’ Mem. Geol. Surv. 1914, pp. 135-37.

L2

LL TT A I IE TT TTT TI

at

126 MR. F. DIXEY AND PROF. T. F. SIBLY ON THE [ vol. lxxiu,.

the dominating escarpment of the Main Limestone -by a narrow,
level or gently sloping, grassy platform which marks the outerop
of the shales. This characteristic landscape feature is well marked
on the eastern side of the Rhymney valley, where the ruins of
Castell Meredydd stand on the limestone-scarp, and it is con-
spicuously developed almost without interruption from the upper
part of Cwm Draethen westwards to the valley between Craig
Llanishen and Cefn Carnau (see photographs, Pl. XII, and section,
fig. 4, p. 120). Near Rhubina and Tongwynlais it is again well
marked, and at the entrance to the gorge of the Taff the limestone-
scarp affords a commanding site for Castell Céch. In two localities,
south of Cefn-On Farm and north of Craig Llanishen, respectively,
a clean-cut displacement of the features, the result of dip-faulting,
is admirably shown.

1. Limestones and shales.—K,. Lower part of the Lower
Limestone of the Geological Survey.

General lithology.—In the Ebbw valley, thinly-bedded lime-
stones of varied character, usually crinoidal and shelly, often
ostracodal, and sometimes gritty, with subordinate shales. In the
Taff valley, the development of shale is little inferior to that of
limestone. Hzmatitic limestones of a-type, precisely similar to
the Bryozoa-Bed of the Avon section, occur in the lower part of
the group.

Thickness.—About 30 feet in the Ebbw valley, increasing to
50 or 60 feet in the Taff valley.

Fauna:

Corals and brachiopods:—

Cleistopora cf. geometrica Edwards & — Schellwienella cf. crenistria (Phillips).

Haime. Orthis michelini L’Eveillé.
Camarotechia mitcheldeanensis
Productus bassus Vaughan. Vaughan. .
Chonetes ef. hardrensis Phillips. _ Spirifer clathratus M‘Coy.
Chonetes stoddarti Vaughan. Syringothyris ef. cuspidata (Martin).
Leptena analoga (Phillips). Eumetria carbonaria (Davidson).

Bryozoa :—Rhabdomeson, Fenestella. Lamellibranchs :—Modiola (2?) sp.
Gasteropods :—Capulids (Orthonychia sp., Platyceras sp.) and small turreted
forms. Ostracods. Fishes :—Psephodus sp.

Good exposures of the beds of this division are found only at the
extremities of the outcrop now under consideration.

On the western side of the Ebbw valley, above Pont-y-Mister,
the stream which descends from Coed- y-Mochyn exposes, at a little
waterfall and in the cascades and banks below it, the section
illustrated by fig. 5 (p. 127). Some 250 yards north of this streaim-
section, a small disused quarry (Mon. 28 SW 38) affords a second
exposure of the same beds, including the calcareous grit at the base,
but the section is much grassed over. No shale-bands appear to
be developed, and no limestone of a-type has been detected. Some

») ae a} aa an ae h

: —.?

part 2] CARBONIFEROUS LIMESTONE OF S. WALES COALFIELD. 127

Ds ¥ ;

i '

_ thinly-bedded limestones in the lower part of the section show seams

i ee ‘smooth calcite-mudstone interbanded with layers of highly
oolitie limestone: the oolitie bands are ostracodal and slightly
gritty, and contain Serpu/a and algal structures.

Fig. 5.—Section of the lower part of the Lower Limestone Shales,
stream below Coed-y-Mochyn, western side of the Ebbw
valley, above Pont-y-Mister (Mon. 28 SW 1). (Vertical

: seale: 1 inch=10 feet.)

4
if

. CRINOIDAL
LIMESTONE

& |
OoOLITE |
(2).

Grey, crinoidal limestone, slightly oolitic and gritty.

Cot Ve Ga Y Cumarotechia mitcheldeanensis and Schellwienell:
= — cf, erenistria abundant. Ostracods. Ihabdomeson.

Shale.

Fine-grained, gritty limestone. Ostracods and Modi-
eng lamellibranchs abundant. A little crinoid-
ébris.

Crinoidal limestone with some shale. In part fine-
grained, gritty (much decalcified).

_ Limesrones

& Grey, crinoidal and shelly limestone, with a basal

8 layer (up to6inches in thickness) of hwmatitic lime-
MALES stone of a-type. The a-limestone (a * bryozoa-bed’
with abundant Rhabdomeson) passes laterally into

(1).
mudstone containing Serpula. Cumarotachia
mitcheldeanensis, Schellivrienella cf. crenistria,
Leptana analoga, abundant. Productus haseue,
Chonetes of. hardreusis, Sp'rifer clathratus.

|

)

|
grey limestone: both enclose pebbles of calcite-
Limestones and shales [poorly exposed]. One band

of limestone shows seams of light-grey calcit »-mud-
stone and dark-grey, oolitic, ostracodal limestone.

Caleareous grit: grey grit, highly calcareous, mica-
ceous, and slightly felspathic, Unfossiliferous.

— At Tongwynlais, in the Taff valley, an excavation on the hill-
side 200 yards east-north-east of the church exposes beds near the
base of the group, while a cutting on the Cardiff Railway, at the
northern end of the village, traverses the upper beds and exposes
their junction with the overlying erinoidal limestones.

128 MR. F. DIXEY AND PROF. T. F. SIBLY ON THE [ vol. Ixxi,

The hillside excavation (Glam. 37 SW A3), in the southern
limb of the Tongwynlais syncline, yields the following section :—
2. Green-grey shales: upper part with many thin layers of fine-grained,
highly gritty limestone yielding ostracods and brachiopods. The limestone-
layers extensively decalcified to a fine, ferruginous sand..............-
to top of section 6 an

1. Crinoidal limestones: grey limestones ; but at the top, a band of
heematitic limestone of a-type, up to 10 inches in thickness, and at the base,
limestone of the same type, with partings of green shale, seen for 2 feet.
Abundant brachiopods (Productus bassus, Chonetes cf. hardrensis, Leptena
analoga, Camarotechia mitcheldeanensis, etc.) ... to base of section 12 feet.

The railway-cutting (Glam. 37 SWA4) les in the northern
limb of the syncline. It extends southwards from Castell-Céch
Tunnel, and traverses a considerable portion of the Lower Lime-
stone Shales. For the most part it lies in the middle group ot
erinoidal lmestone and oolite, but at the northern end it exposes
the underlying limestones and shales to a thickness of about
20 feet. These latter beds are highly fossiliferous, yielding all
the types of our faunal list, above. ‘Chonetes cf. hardrensis teems
in many bands of limestone. Productus bassus is abundant,
Chonetes stoddarti rare. Cleistopora ct. geometrica occurs in
the shaly cappings of some limestone-bands. The strata comprise
limestones and shales interbanded in lenticular fashion, and a
considerable development of argillaceous limestone. The shales,
erey to black, calcareous and micaceous, occasionally contain
numerous ostracods or Fenestella, with a few lamellibranchs or
small Chonetes. The limestones are predominantly dark-grey
shelly rocks, with an abundance of brachiopods and ostracods,
though seldom conspicuously crinoidal. But this shelly type of
limestone is intimately interbanded with very fine-grained, poorly
fossiliferous limestone, sometimes smooth and splintery, sometimes
laminated and gritty.

These sections in the Taff valley exhibit a development of shale
equal or nearly equal in amount to limestone, a considerable’
change from the character of the group in the Ebbw valley.
Limestone ot a-type is also developed in larger amount, but
evidently at the same horizon. In the neighbourhood of Ton-
gwynlais, moreover, the limestones of a-type have undergone some
secondary enrichment in hematite, and this has led to more than
one trial of the beds for iron-ore. Excellent specimens for the
study of these rocks may be obtained, either from the excavation
at Tongwynlais (Glam. 37 SW \8) described above, or from the
spoil-heap of an old level north of Rhubina (Glam. 37 SW A11),
mentioned in the Geological Survey memoir! Specimens E 2465
& E 2466 of the Geological Survey collection were obtained from
the latter locality. E2465, illustrated by a microphotograph
in Plate, fig. 1, of the memoir, possesses a matrix of clear,
granular calcite, comparatively free from hematite: in E 2466, on
the other hand, the matrix has suffered much ferrification. In

1 Newport Memoir, 2nd ed. p. 24.

ya
part 2) CARBONIFEROUS LIMESTONE OF S. WALES COALFIELD. 129

the Rhubina spoil-heap, as in the stream-section in the Ebbw
valley (Mon. 28 SW \1), the a-limestone often encloses pebbles of
caleite-mudstone (containing Serpula) formed by the churning-up
of contemporaneous deposits, an indication of eurrent-action that is
in keeping with the rolled character of the organic remains.

2. Crinoidal limestone and oolite—-K, or K,. Upper
and major part of the Lower Limestone of the Geological Survey

General lithology.—Non-oolitic or slightly- -oolitic crinoidal
limestone, and oolite which is, as a rule, crinoidal. In the east
(Ebbw valley), the development of oolite is subordinate and
apparently sporadic: in the west (Taff valley) oolite forms the
upper and larger part of the group. Dolomitization is frequent,
and (for the greater part) evidently a subsequent feature.

Thickness.—Between 40 and 5V feet on the western side of
the Ebbw valley: increasing south-westwards, to 100 feet or more
in the Taff valley at Tongwynlais.

Fauna.—Brachiopods are seldom abundant; the chief forms
will be noted in the description of exposures. Fenestella and
Rhabdomeson are occasionally common. Ostracods occur in oolitic
bands at the base of the group in some localities.

In the Ebbw valley, the stream-section below Coed-y-Mochyn
(Mon. 28 SW X1) exposes about 12 feet of limestone at the base
of the group (fig. 5, p. 127). The rock is richly crinoidal and
shelly, and contains Camarotachia mitcheldeanensis in abundance:
in thin section, it proves to be slightly oolitic, with a few quartiz-
grains and oceasional ostracods and Rhabdomeson. On the hillside
50 yards to the north, an old quarry (Mon. 28 SW X2) gives an
almost complete section of the division. The lowest beds exposed
are those of the stream-section, here yielding Leptena analoga
and Sehellwienella cf. erenistria in abundance, together with
Syringothyris cf. cuspidata, Fenestella, and the fish-tooth De/-
todus gibbus. For the rest, the beds are crinoidal, occasionally
oolitic limestones, gener: ally showing conspicuous turrent- lamination,
and extensively vein-dolomitized. About 330 yards farther north,
a small excavation on the hillside above Dan-y-Graig Brickworks
shows a white oolite which lies near the top of the group.

On the eastern side of the Rhymney valley north of Machen,
good exposures are afforded by the crags and ‘old workings along
the scarp which extends east and west of Castell Meredydd. Here
the limestones have suffered very extensive dolomitization, but the
predominance of crinoidal rock, current-laminated in some beds,
and the development of oolite-bands, are clearly seen.

Westwards from the Rhymney valley, to the neighbourhood of
Rhubina, the beds are seldom well exposed, although often con-
spicuous in their effect upon the topography. Whenever seen,
they are highly dolomitized limestones, often crinoidal, but other-
wise poorly fossiliferous, and as a rule fine-grained. The dolomiti-
zation in this portion of the outcrop may be partly contemporaneous.
The Geological Survey map (Newport sheet) represents the limestone

—————————

130 MR. F. DIXEY AND PROF. T.F.SIBLY ON THE [ol. xxi,

group as thinning out immediately south-west of Draethen and
reappearing a mile farther up Cwm Draethen. We consider such
a thinning-out to be highly improbable, and prefer to regard
the outerop of the limestones as continuous along the steep
escarpment slope on the northern side of Cwm Draethen.

The group is well exposed in some old quarries north of Rhubina,
and even better displayed in the railway-cutting south of
Castell-Céch Tunnel, Tongwynlais. In both localities,
dolomitization has affected the beds in slight degree only. The
railway-cutting (Glam. 37 SW 24) traverses the group from
base to summit. The beds dip southwestwards at 35° to 40°
throughout most of the section; but, at the southern end, their dip
increases to 60° and over in a sharp roll. At the base, red-stained
crinoidal limestones succeed sharply the limestones and shales of
the underlying division; at the top, grey oolite gives place to
deeply iron-stained argillaceous limestone and crinoidal limestone,
which alternate in thin bands for 8 to 10 feet before the section is
terminated by a bank of Glacial gravel. The total thickness of
approximately 100 feet comprises about 35 feet of crinoidal non-
oolitic limestone below and 65 feet of crinoidal oolite above; but
a grassy gap in the section of the lower beds, equivalent to about
12 feet, may indicate some development of shale. The brachiopods
in the limestones include Schellwienella cf. crenistria, Camaro-
teechia mitcheldeanensis, Spirifer clathratus, Syringothyris ct.
cuspidata, and asmall Athyris: of these, only the two first-named
are abundant.

The Tongwyulais railway-section shows a development of the
limestone group marked by an unusually clear contrast between
non-oolitic limestone below and oolite above, although even there a
few seams of coarse oolite are intercalated in the crinoidal lime-
stones and occasional non-oolitic bands oecur within the oolite. In
the old quarries north of Rhubina, crinoidal limestone and oolite
alternate repeatedly throughout the group.

Two disused quarries, lying respectively east and west of Castell
Céch, expose the upper beds of the limestone group. Each shows
a considerable development of oolite, and each exposes the base
of the overlying shale-division, but the sections are much over-
erown and difficult of access. In the quarry east of Castell Coch
the limestone is much dolomitized.1

3. Shales with thin limestones.—k,,.

General lithology.—Dark-grey to black shales, w ith sub-
ordinate thinly eeaded emcereaee The limestones always richly
crinoidal and shelly.

Thickness.—In the Ebbw valley, 50 feet or less; increasing
to about 100 feet at Tongwynlais in the Taff valley.

1 Fig. 4 of the plate in the Newport Memoir, 2nd ed., illustrates a partly-
dolomitized oolite from the quarry west of Castell Céch. The selective
dolomitization of the ooliths points to vein-dolomitization.

——————

a

part 2] CARBONIFEROUS LIMESTONE OF 8. WALES COALFIELD. 131

Fauna:
Corals and brachiopods:—

Cleistopora cf. geometrica Edwards & | Camarotechia mitcheldeanensis

Haime. Vaughan.
Spirifer clathratus M‘Coy.
Productus aff. bassus Vaughan. Syringothyris ef. cuspidata (Martin).
Pustula subpustulosa Thomas. Spiriferina octoplicata (J. de C.
Chonetes cf. hardrensis Phillips. Sowerby), mutation 3 Vaughan.

Schelliwienella cf. crenistria (Phillips). | Athyris roissyt L’Eveillé.
| Eumetria carbonaria (Davidson).

Bryozoa :—Rhabdomeson, Fenestella, Lamellibranchs :—A small Modiola-
like species. Ostracods.

Good exposures of the beds are few, and only two sections, now
to be described, have yielded any considerable fauna.

In the strike-valley between Craig Llanishen and the western
end of Cefn-On, and about 600 yards west of the Caerphilly
railway-tunnel, the northern bank and the bed of a stream expose
black shales with a few thin lenticular bands of limestone (Glam.
37 SW X10). These beds lie at the base of the group, and succeed
sharply the limestone of the underlying group, which is exposed
at one point in the southern bank. The thin limestone-bands, of
the usual crinoidal and shelly type, contain irregular patches and
distinet pebbles of very fine-grained limestone: they have yielded
Pustula subpustulosa, Productus ct. bassus, Chonetes ct. har-
drensis, Schellwienella cf. crenistria, Athyris roissyi, and Syringo-
thyris ef. cuspidata, the tirst and last-named being notably
common; and they contain ostracods in abundance.

On the eastern side of the Taff gorge, Castell-Coéch Quarry
(Glam. 37 SW A5) affords the second section, at the point where a
small bluff of thinly-bedded limestones and shales protrudes from
the scree of limestone-débris at the southern end of the quarry.
These beds, lying about the middle of the group, consist more
largely of limestone than of shale. The limestones vield C/e?sfo-
pora and all the other types specified in our faunal list, above.
Productus att. bassus, Schellwienella ct, crenistria, Camarotachia
milcheldeanensis, and Rhabdomeson sp. are particularly abundant.
One band of limestone, rich in crinoid-débris and brachiopods,
contains ostracods and a small Wod/ola-like shell in abundance.

Castell-Céch Quarry also exposes the wppermost beds of the
group, unfossiliferous micaceous mudstones immediately under-
lying, and succeeded sharply by, the dolomites that form the base
of the Main Limestone. The junction of Lower Limestone Shales
and Main Limestone is again exposed at the eastern extremity of
the district here described, in the lowest beds of Dan-v-Graig
Quarry, Risea. There, however, we find an alternation of hard
slightly-dolomitic shale with finely-crystalline dolomite.

_ — a

OP aa»

132 MR. F. DIXEY AND PROF. T. F. SIBLY ON THE _ [ vol. ]xxini,

West of the Taff.

In the district west of the Taff valley the Lower Limestone
Shales are, to a great extent, concealed by Boulder Clay and
Glacial gravel, but the three divisions established east of the
Taff can be recognized. The development of shale in the lowest
division appears to increase considerably as we pass westwards.
This phenomenon continues the change already noticed in the
outcrop east of the Taff: it was recognized by the officers of the
Geological Survey on the evidence of exposures near Bolgoed,!
west of the Ely valley, and expressed on the Survey map (Bridgend
sheet) by the representation of three divisions in the Lower
Limestone Shales west of Groes-faen, namely, lower and upper
shale-divisions separated by a band of limestone. The thickness
of the whole series appears to increase westwards, but the limestones
which form the middle member do not contribute to this increase ;
probably their lowest beds are split up by shales in a westerly
direction, and so become merged in the underlying group of shales
and limestones.

Between the Taff and the Ely, a distance of about 5 miles,
outcrops of the Lower Limestone Shales are practically confined
to two strips, each about a mile and a quarter long; one
lying south and south-west of Pentyrch, the other extending
through Groes-faen to the neighbourhood ot Croftau. At Creigiau,
a cover of Mesozoic rocks conceals the beds, but elsewhere the
masking is due to Glacial drift. The beds do not crop out along
the margin of Garth Wood, on the western side of the Taff valley,
as represented on the Geological Survey map (Cardiff sheet) :
they lie buried under drift immediately to the south, and the scarp-
face of Garth Wood belongs wholly to the Main Limestone. At
Groes-faen, the middle and upper members of the Lower
Limestone Shales produce landscape features similar to those
which are so conspicuous in the country east of the Taff,. but
less pronounced. The limestone group gives rise to a low, wooded
ridge, to the north of which les a shallow strike-valley, or a
grassy flat, marking the outcrop of the shales. The outcrops
and their accompanying features are displaced by dip-faults
immediately west of Groes-faen: farther west, the features die out
as the beds pass under a covering of drift.

West of the Ely the drift-cover is even more extensive. The
beds crop out for a short distance at Caer-gwanat-isaf, immediately
west of the Ely valley and north of Hensol Park, and are seen
again over a small area between Ystradowen and Llansannor ;
between these two localities, their extent is almost entirely
conjectural.*

1. Limestones and shales.—The lower group is nowhere
exposed between the Taff and the Ely. West of the Ely, and

! Bridgend Memoir, p. 9
> Ibid. pp. 7 & 9, and Bridgend map, drift edition.

= Ed ai i i ee

part 2} CARBONIFEROUS LIMESTONE OF 8. WALES COALFIELD. 133

north of Hensol Park, it is represented by shales exposed in a well
and in an adjacent gully 200 yards north-east of Bolgoed Farm.
These beds have yielded no fossils.

2. Crinoidal limestone and oolite.—The outcrop of the
middle group is marked by many disused quarries, and the
exposures indicate a development closely similar to that observed
at Tongwynlais: namely, lower beds of richly crinoidal limestone,
stained red as a rule, and upper beds of oolite, occasionally vein-
dolomitized and iron-stained but usually fresh. The oolite, in a
fresh condition, is at present worked in a quarry LOO yards north-
east of Maesmawr Farm, east of Groes-faen. A quarry situated
immediately west of Caer-gwanaf-isaf (Glam. 42 NW 4) exposes
the topmost beds of the oolite, with some intercalation of crinoidal
limestone, overlain by shales. In the outcrop south-east of
Llansannor, where the oolite has been quarried at Pen-cyrn and at
Newton Farm, it is found to be highly crinoidal, and to pass up
into thinly-bedded, argillaceous limestone.

As in the outcrop east of the Taff, the brachiopod-fauna of these
limestones is poor’ NSchellwienella ct. crenistria is the only
abundant form, but Chonetes ct. hardrensis, Camarotaechia
mitcheldeanensis, and Spirifer clathratus have been recorded
at several localities, including the above-mentioned quarry at
Caer-gwanaf-isat.

3. Shales with thin limestones.—The beds of the upper
group are seldom exposed. Two exposures, however, have yielded
a rich fauna practically identical with that of the same division
east of the Taff. These are a small quarry (Glam. 42 NW \23)
lying midway between Groes-faen and Brotiscin Quarry, and a
stream-section (Glam. 42 NW \22) situated 150 yards south-west
of Pantaquesta Farm, north of Hensol Park. The former exposes
beds very near the top of the Lower Limestone Shales, while the
latter reveals a lower horizon in the group: in each case the beds
are shales with thin limestones, the shales apparently barren, the
limestones erinoidal and shelly. The following brachiopods have
been recorded at both localities :—

Productus aff. bassus. Camarotechia mitcheldeanensis.
Productus burlingtonensis. Spirifer clathratus.

Pustula subpustulosa. Syringothyris ef, cuspidata,
Chonetes cf. hardrensis. Athyris roissyi.

Schellivienella ef. crenistria. Eumetria carbonaria,

In addition to the species enumerated above, the Groes-faen ex-
posure has yielded Spiriferina octoplicata, and the section near
Pantaquesta Farm, Cleistopora cf. geometrica, Ostracods, small
gasteropods (Capulids), and Rhabdomeson oceur at both localities.

East of Llansannor, the Geological Survey map represents a
small outlier of the Main Limestone, unaccompanied by faulting.
Our mapping shows this area of Main Limestone as a tongue,

134 MR. F. DIXEY AND PROF. T. F. SIBLY ON THE [ vol. Ixxin,

continuous with the outcrop of Limestone on the north, but
faulted against Lower Limestone Shales on the east. The fault,
running south-westwards past Pen-cyrn to Pen-y-lan, cuts out
almost the whole of the shales with thin limestones at Pen-cyrn.
This would account for the apparent greatly-reduced thickness of
the shale group (estimated from width of outerop) at the latter
place, mentioned in the Geological Survey memoir.!

About 650 yards east of Llansannor Church, black shales and
thinly-bedded argillaceous limestones are exposed in a_ small
excavation and in the lane adjacent to it (Glam. 41 SE X47).
The limestones, often ostracodal, contain many brachiopods,
including Productus aff. bassus and Spiriferina octoplicata. The
shales yield small JVodola-like lamellibranchs.

(B) Main Limestone.

The sequence of zones is most nearly complete in the west of
the district, and there it can be recognized in detail. The area
west of the river Taff will, therefore, be described first.

West of the Taff.
Zaphrentis Zone and Lower Caninia Zone: Z & C,

The sequence Z—C, is represented by one colour on our map
(Pl. XV) because ev idence for a satisfactory delimitation of Z and
C, is not forthcoming.

In the westernmost part of the outcrop the succession is mainly
one of undolomitized crinoidal limestones and oolites, contempora-
neous dolomitization being practically confined to two horizons,
namely, a lower level, in Z, and an upper level (the Laminosa
Dolomite ) in C.. Eastwards, dolomitization affects a steadily-
increasing portion of the sequence until, in the Taff valley, it has
produced an unbroken succession of doloinites.

The following table summarizes the sequence in the outcrop
between Miskin and Groes-faen. where the beds are, on the whole,
best exposed. No precise limits can be assigned to the several
subdivisions: and the thicknesses stated, estimated in most cases
from dip and outcrop, are only rough approximations :—

Z& C, between Miskin and Groes-faen.
Feet.
“8. Caninia Oolite: pale-grey oolite, thickly-bedded to massive.
7. Laminosa Dolomite: finely-crystalline dolomite, crinoidal +340
) in part.
6. Crinoidal limestones, dolomitic at the base. A little chert. \ 18¢
Abundant corals and brachiopods (y C)).
Oolite : crinoidal, current-bedded ........................... 20
P= Dolomites and dolomitic limestones, crinoidal in part. A 210
little chert near the base.

Z-~ 4. Crinoidal limestones, with argillaceous layers, chert, and
beekite. Zaphrentis delanouei and abundant brachiopods + 35
L (Z,).

1 Bridgend Memoir, p. 11.

se Bt

rt 2] CARBONIFEROUS LIMESTONE OF 8. WALES COALFIELD. 135

The top of the Caninia Oolite, which is the generally-recognized
dividing line between C, and C,,! thus marks the upper limit of
the series Z—C,. This constitutes the boundary between Lower
Avonian and Upper Avonian, as established by Mr. E. E. L. Dixon
on stratigraphical grounds. It marks the culmination of a shallow-
ing movement in the South-Western Province which produced the
widespread development of a Modiola phase at the base of C,, and
even led to emergence and consequent unconformity in some areas.”
The significant Modiola phase has been recognized at Miskin in
the area here described, where it succeeds the Caninia Oolite

sharply (p. 140).

4. Crinoidal limestones: Z,.—These beds, forming the base

of the Main Limestone, are essentially dark-grey or black crinoidal

7

limestones, thinly bedded and flaggy, with argillaceous bands and
tches. A current-bedded rock, consisting of richly-crinoidal
nds separated by lenticles and streaks of compact argillaceous
limestone, is often developed. The development of chert in
nodular or banded forms and the beekitization of fossils are
frequent, and silicification sometimes results in the formation of
small nodules of milk-white banded chalcedony.

The beds are exposed at many points between Penlline and the
neighbourhood of Pentyrch: the chief exposures are specified in
the faunal list, below. Eastwards from Creigiau, dolomiti-
zation develops rapidly: but, even in their highly-dolomitized
condition, the beds are readily identified by their general characters
and their abundant brachiopods. Thin seams crowded with
Chonetes cf. hardrensis are especially characteristic.

a —— —

Fauna. Bocality.

Genera and species of
corals and brachiopods.

Zaphrentis delanouei Edwards & Haime, Car-

Pustula subpustulosa Thomas ............ Sigh pian ea x

Productus burlingtonensis Hall, Vaughan ... X oR is

Productus ef. concinnus Sowerby ............... Pen ne iy
Chonetes ef. hardrensis Phillips ...... Latin XA|xXA|XAIXA, X | XA!
Leptwna analoga (Phillips) ..............0:0006) Ko [ose | ee ee ee A
Schellwwienella cf. crenistria (Phillips) ......... XA) xX |xXA XA XA|XA
Mememiehatind L'Yiveillé.........:.......0..060.] ne [RO]. | ve) XOX |
Camarotechia mitcheldeanensis Vaughan ... X | ...|XA X Xx XA
Spirifer clathratus M‘Coy ............00000000. XA) XA) XA XA XA xA
Syringothyris cf. cuspidata (Martin) ......... X | XC! ... xOi x 1x*C

Athyris glabristria (Phillips), Vaughan ...... y

C =Common.

“A=Abundant.

1 A. Vaughan, Q. J. G. S. vol. Ixxi (1915-16) folding table facing p. 32.
2 Gower paper, p. 542. See also ‘The Country around Carmarthen " Mem.
Geol. Surv. 1909, pp. 81-82, and ‘The Country around Haverfordwest’ ibid.

-* 1914, pp. 127-28.

136 MR. F. DIXEY AND PROF. T. F. SIBLY ON THE [ vol. Ixxin,

1. Quarry (Glam. 41 SW A 1), onthe west side of the road, 400 yards
north of Penlline Church.
. Exposures (Glam. 41 SE \ 2), a little west of Coed Pen-cyrn, east
of Llansannor.
3. Crags (Glam. 41 SE \ 3), 200 to 250 yards west of New Barn, east
of Llansannor.
4. Exposure (Glam. 42 NW 114), 700 yards east of the cross-roads,
Miskin.
5. Old Quarry (Glam. 42 NE X 2), 100 yards east-north-east of Craig
Channel, Pant-y-gored.
Old Quarries (Glam. 42 NE \'5), 700 yards south-east of Pentyrch
Church.

ho

oe

5. Dolomites and dolomitiec limestones: Z.— From
Miskin eastwards, this is essentially a series of grey finely crystal-
line dolomites, with numerous small nests of calcite and dolomite.
Chert is developed sporadically near*the base. Crinoid-ossicles are
often abundant, but brachiopods are rare. WSpirifer clathratus
and Schellwienella ct. crenistria are the only species of the latter
group recorded, unless the fossiliferous band of Ty-nant Quarry
(p. 188) is included in this division.

The beds are poorly exposed. ‘Two sections near Miskin, and
one east of Creigiau, expose the base of the group and the passage
into the underlying crinoidal limestones: these are (1) crags
(Glam. 42 NW 14), representing old workings, 700 yards east of
the cross-roads at Miskin, (2) a small quarry midway between
these crags and the cross-roads, and (3) old quarries (Glam. 42
NEX5) 700 yards south-east of Pentyrch Church. Ty-nant
Quarry. in the Taff valley, affords the only good exposure of the
upper beds of the group. A fossiliferous band in this quarry
should perhaps be included in this group, that is, in Z, rather than
in the Canrnia Zone (see p. 1388).

In the drift-covered area west of Miskin, exposures are few, and
little is known about the group. The lower part retains its
dolomitic character as far west as the ground north of Ystradowen ;
but, farther west, dolomitization at this level seems to diminish.
The lower portion of a thick oolite which is developed north of
Llansannor and Penlline appears to represent the upper beds of
this group in the extreme west. This oolite is well seen in a
quarry (Glam. 41SEX4) at New Barn, 800 yards east of Llan-
sannor Church: it is there a dark-grey rock containing Sp7rifer
clathratus and a few other brachiopods.

6. Crinoidal limestones, ete.: yC,—\This division is a
series of thinly-bedded, richly-crinoidal, grey or black limestones,
with a considerable development of poorly-crinoidal argillaceous
bands, usually buff-coloured. An irregular development of black
argillaceous streaks, accompanied by contemporaneous brecciation
and evidently due to current-action, is not uncommon. Many of
the crinoidal beds are very rich in brachiopods and corals, together
with gasteropods and bryozoa. Nodular chert is developed
occasionally, in small amount.

b 2] (CARBONIFEROUS LIMESTONE OF 8. WALES COALFIELD. 137

The group is well-exposed in three quarries between Groes-faen
Saji Miskin, and farther west in two quarries, near Ystradowen
and Llansannor respectively (see faunal list, below). In Brofiscin
Quarry (Glam. 42 NW \16), north of Groes-faen, finely-crystalline
blue-grey dolomites form a band, about 12 feet thick, at the base
of the crinoidal limestones, and are underlain by a thickly-bedded

oolite, seen toa thickness of about 20 feet. In an old quarry
(Glam. 42 NW A15) 400 yards east of Miskin, the base of the
crinoidal limestones is highly dolomitic. Both in an old quarry
(Glam. 42 NW A17) north of Croftau and in a quarry (Glam.

41 SEA1) east of Ash Hall, Ystradowen, the crinoidal limestones
are seen to pass up into the Laminosa Dolomite.

Fauna. Locality.

Genera and species of ah oe
corals and brachiopods. )

Amplexus coralloides Sowerby <a
Zaphrentis omaliusi Edwards & Haime, Car-
ruthers, including Z. densa Carruthers ......... x
Zaphrentis es gc. pts ves vou devsedsunave | x |
Caninia aff. cornucopie Michelin, Carruthers .... ...
es cic cc eee ras sens cececas savers ers ) ref
Pustula aff. subpustulosa Thomas .................. |
Productus cf. concinnus Sowerby .................. ide
Productus aff. cora D’Orbigny ..................... Eee
Chonetes cf. hardrensis Phillips .....................) ...
Chonetes ef. buchiana De Koninck............... .. a
Papilionaceous Chonetes .....................0..000 000] me
Leptena analoga (Phillips) .. dene eo
Schellivienella ef. crenistria (Phillips), ibe Sy »
Orthis michelini L’Eveillé ........ ET RAR EN A
Orthes resupinata (Martin) ...........................| X
x

OES

x
XK KKK KKKKK X
XXX:

x

_Spirifer clathratus M‘Coy ......

| Syringothyris cf. cuspidata (Martin) .

_Spiriferina cf. laminosa M‘Coy ...... waa baes

| Reticularia aff. lineata (Martin), Vaughan . sive x
_ Athyris glabristria (Phillips), Vaughan .. ™\ eee

xx xxXxXxK XXX:
xxxKKKKKKKKXKKKKKKXKX:

MEK MDS:

:
:

ee $$
»

1. Old Quarry (Glam. 41 SE ) 5), near the western side of King Coed,
f north-east of Llansannor.

2. Quarry (Glam. 41 SE \ 1), 550 yards east of Ash Hall, Ystradowen.
3. Old Quarry (Glam. 42 NW \ 15), quarter of a mile east of Miskin,
4. Old Quarry (Glam. 42 NW \ 17), 150 yards north of Croftan.
5. Brofiscin Quarry (Glam. 42 NW \ 16), 300 yards north of Groes-faen.

Gasteropods are usually abundant : the forms include Luomphalus
(particularly abundant at Ystradowen), Bellerophon, and a Capulid.
Bryozoa, including Fenestella, Monticuliporids, and Stenoporids,
are sometimes abundant.

138 MR. F. DIXEY AND PROF. T.F. 8IBLY ON THE [| vol. Ixxiui,

While the fauna admits of no doubt in assigning the beds to
yC,, a separate recognition of Horizon y is not possible. Specially
characteristic features are the occurrence of Caninia aff. cornu-
copie and the abundance of Zaphrentis densa, Orthis michelini,
and Spiriferina cf. laminosa.

Large vesicular Caninids (Caninia patula, C. cylindrica) are a
conspicuous feature of the fauna at this level in the Avonian
generally. No specifically determinable corals of this type have
been found in our district; but the upper beds of the crimoidal
limestones contain many patches of coarsely-crystalline calcite,
the form and size of which suggest large Caninids, and in some of
these patches remnants of thickened septa have been observed.

Eastwards from Groes-faen, the crinoidal limestones of
this group pass rapidly into dolomites, and dolomitization has
usually obliterated the fossils, with the exception of the highly-
resistant crinoid-ossicles. Immediately east of Creigiau, however,
a small quarry (Glam. 42 NEA3), situated 170 yards north-north-
west of Craig Channel, exposes crinoidal dolomites, together with
some beds of black crinoidal limestone that have suffered only
a patchy dolomitization. Corals and brachiopods are numerous
throughout the beds of this section: they include Zaphrentis
omaliusi, Zaphrentis sp. nov., Orthis resupinata, and Spiriferina
ef. aminosa, a fauna which seems to warrant the reference of
the beds to yC..

In the dolomite-series of the Taff valley, the crinoidal
dolomites that form the upper beds of Ty-nant Quarry (Glam.
37SWA1) include a richly-fossiliferous band which represents _
either the base of our yC, group, or a slightly-lower horizon, in Z,.
This band consists of red completely- crystalline dolomite, in which
all the brachiopods and corals, and many of the crinoid-ossicles,
are represented by casts or moulds. The following corals and
brachiopods occur :—

Zaphrentis konincki; common. Camarotechia mitcheldeanensis; rare.
Schellwienella cf. crenistria; abun- | Spirifer clathratus ; common.

dant. Syringothyris ef. cuspidata.
Orthis michelini. Spiriferina cf. lamimosa ; abundant.

Orthis reswpinata; very abundant.

7&8. Laminosa Dolomite and Caninia Oolite: C,
(upper part).—These two divisions have been traced from the
western side of the Dawen valley, north of Penlline, as far east
as the neighbourhood of Groes-faen, but it is only between the
latter place and Miskin that they are well displayed.

Between Miskin and Groes-faen, the collective thickness of the
Laminosa Dolomite and the Caninia Oolite probably remains
fairly constant at about 340 feet. Hach division has been proved
to a thickness of over 100 feet, but it has been impossible to
determine even approximately a boundary between the two.

is

:
part 2} CARBONIFEROUS LIMESTONE OF 8. WALES COALFIELD. 139

_Laminosa Dolomite.—Dark-grey or blue-grey finely-crystal-
line dolomites, slightly crinoidal towards the base, but otherwise
apparently unfossiliferous. In the lowest beds, however, rounded
patches of coarsely-crystalline calcite possibly represent the re-
erystallized infillings of cavities in fossils.!

The face of an old quarry (Glam. 42 NW A17) situated 150
yards north of Croftau shows the base of the Laminosa Dolomite
in contact with the underlying crinoidal limestones ; and a cutting
which runs northwards from the quarry exposes fully LOO teet of
dolomite.

The following are the chief exposures of the Laminosa
Dolomite, enumerated in order from west to east :—

Old Quarry (Glam. 41 SW 4), beside the road at Ty’n-y-graig, on the
western side of the Dawen valley, north of Craig Penlline.

Old Quarry, 150 yards south of St. Ann’s Chapel, south of Brynsaddler.

Old Quarry (Glam. 42 NW A 17), 150 yards north of Croftau; and cutting
extending northwards from the quarry.

Exposure on the northern side of Brofiscin Quarry, north of Groes-faen.

Caninia Oolite.—Essentially, pale-grey thickly-bedded oolite,
often with imperfect stratification. The oolitic structure is
variably coarse or fine. The rock is typically foraminiferal.
Current-bedding is frequent, and many current-bedded portions
give evidence of contemporaneous erosion in an abundance ot
angular or rounded fragments of oolite. Apart from crinoids
and foraminifera, fossils are almost confined to an abundance of
the brachiopod Schellwienella cf. crenistria, or the gasteropods
Bellerophon and Euomphalus, in rare bands. Syringopora ct.
distans, S. cf. reticulata, Seminula cf. ficoides, and papilionaceous
Chonetes, occur rarely. In the main mass of the Caninia Oolite
crinoidal bands are few, but near the top the rock may become
highly ecrinoidal, as seen in a quarry north of Croftau (Glam.
42 NW X18). The crinoidal beds at this locality contain papilio-
naceous Chonetes, and have yielded a single corallite of Litho-
strotion martini (7).

In an old quarry at the Castell-y-Mynach Arms (Glam. 42 NW
\20), near Croftau, the Modiola phase of C, is seen resting upon
an eroded surface of the Caninia Oolite (see p. 141).

The following are the chief exposures of the Caninia Oolite,
named in order from west to east :—

Old Quarry (Glam. 41 SW A 5), at the south-eastern end of Coed Mansel,
on the western side of the Dawen valley, north of Craig Penlline.
Ted agian in woods (Graig), 750 yards north-north-east of Llansannor
ure
Old Quarry (Glam. 41 NE ) 8), a quarter of a mile south of Brynsaddler.
Quarry (Glam.42 NW A 8), 200 yards west of Caer-gwanaf-uchaf, on the
western side of the Ely valley near Miskin.

' Compare E. E. L. Dixon, Gower paper, p. 483.

Q.I.G.S8. No. 290. M

140 MR. F. DIXEY AND PROF. T. F. SIBLY ON THE | vol. lxxiu,

Old Quarry (Glam. 42 NW A 21), beside the road 400 yards north-north-east
of the cross-roads at Miskin.

Old Quarry (Glam. 42 NW X 20), at the Castell-y-Mynach Arms, west-north-
west of Croftau.

Quarry (Glam. 42 NW X18), 350 yards north of Croftau.

Old Quarry, 300 yards north-east of Brofiscin Quarry, near Groes-faen.

In the last-named exposure, the Canznia Oolite has been traced
a little to the east of Groes-faen. Neither the Lamzinosa Dolomite
nor the Caninia Oolite has been recognized farther east. Both
become merged in the series of dolomites which constitutes the
whole of C, in the Taff valley.!

Upper Caninia Zone: C,+8,.?

The series, C,+S,, includes all the beds between the Canznia
Oolite below and the Main Seminula Zone (S,) above. Its upper
limit, the base of 8,, is defined by the appearance of Cyrtina
carbonaria. Essentially, this is a series of standard limestones in
which C, and 8, are faunally continuous ; but a Modiola phase is
found to form the base at the only locality where that horizon is
exposed.

Exposures east and west of the Ely River, in the neha
of Miskin, enable us to establish the following general succes
sion :-—

(C,+8,] in the neighbourhood of Miskin.

‘Feet.
(12. Thinly-bedded limestones of very varied char- |
acter, including crinoidal-shelly limestones,
| oolites, and black calcite-mudstones. Litho-
Gao ce strotion martini abundant.
(= HBG ay. 4 11. Thickly-bedded, grey, crinoidal oolite, in part +150 .
current-bedded and contemporaneously brec-
| ciated. Occasional bands of dark, thinly-
bedded, gasteropod - limestone. Cyatho-
L phyllum @ abundant.
(10. Thinly-bedded, dark, crinoidal limestones. }
Beds of dolomitic limestone or finely-crys-
| talline dolomite, and partings of shale or
J shaly limestone occur, but are subordinate. | 00
| 9. Modiola phase: a varied group, comprising
| calecite-mudstone, dolomite, oolite, breccia,
etc. Over 16 feet thick (direct measure-
L ment).

Lower C,.

9. Modiola phase.—This is exposed in an old quarry behind
the Castell-y-Mynach Arms, between Croftau and Miskin, where
it forms the top of the quarry-face and is seen to rest upon an
uneven surface of the Caninia Oolite. The top of the phase is not
seen. The details of the section are as follows :—

' But see footnote on p. 143.
* Equivalent to the Upper Syringothyris Zone (C,) and the Lower Seminula
Zone (S,).

Modiola phase at the base of C,.—Old Quarry at the Castell-
y-Mynach Arms, near Croftau (Glam.'42 NW A 20).

Feet inches.

7. Calecite-mudstone: much like that of (5)......... seen for 2 0
6. Oolitic limestone: dark grey to black. Athyrids of
Seminuloid form fairly numerous ......... 0 6

5. Calcite-mudstones: dark grey to black, weathering to
a white skin. Thickly-bedded, with partings of black
shale and platy calcite-mudstone ..................0...0....... 8 0
. Dolomite: thinly-bedded, and very fine-grained (in thin
section under the microscope, irregular patches of ex-
ceedingly fine-grained dolomite enclosed by dolomite of
ee a a a 0
3. Limestone-breccia: fragments of oolite and of calcite-
mudstone, similar in character to the nodules of (1):
matrix of fine-grained grey limestone. The fragments
more numerous in the lower than in the upper part ...... 1 6
Eos cack. sii ce. sess sese. Se Oe Pee ae a ae OPE 0 2
1. Rubbly limestone and red marl, loosely coherent.
é limestone-nodules are rounded fragments of (a) dark
oolite, such as occurs in the underlying Caninia Oolite,
-and (b) dark calcite-mudstone, such as forms (5) and (7),
sometimes structureless, sometimes exhibiting wavy or
contorted lamination. The red marly matrix is formed

~

a largely of ooliths, which were probably derived from

fragments of oolite by gentle attrition. (Resting sharply
upon, and filling up inequalities in the surface of, the
a

Total thickness-of Modiola phase seen......... 16 2

| bo

This development of the C, Wodiola phase resembles very closely
that in the eastern district of Gower, described by Mr. E. E. L.
Dixon.!

10, 11, & 12. Standard limestones.—The general lithology
has been described in the table on p. 140. The faunal character-
istics may be detined by means of a tabular list of fossils, supple-
mented by notes on salient features.

A large element of faunal continuity throughout the series is
evident from the table (p. 142). On the one hand, however, several
features of Group 10 serve to differentiate this group from the

rest of the series, and to characterize it as Lower C.: such are
_ the abundance of Seminula cf. ambiqua, the comparative scarcity

a

of Productus corrugato-hemisphericus and Cyathophyllum @, and
the absence or rarity of Carcinophyllum and Lithostrotion2 On

the other hand, groups 11 and 12 represent Upper C, and §,, and

together constitute Horizon ¢ as emended by Vaughan,’ well

' Gower paper, pp. 485-86.
? Compare the Burrington-Combe section, Mendips; A. Vaughan, Q. J.G.S.

_ vol. Ixvii (1911) pp. 368-69.

* «In the South- Western Province, Horizon é includes Upper C, and §, , that is,
from the maximum of Cyathophyllum » to the incoming of Cyrtina carbonaria,’
A. Vanghan, Q. J. G. S. vol. Ixxi (1915-16) p. 18. The base of Horizon ?,
_and, therefore, the boundary between our groups 10 and 11, is the division-

line between Tournaisian and Viséan adopted by Delépine and Vaughan :

ibid., folding table facing p. 32.
| M2

142 MR. F. DIXEY AND PROF. T. F. SIBLY ON THE [ vol. Ixxin,

Lower C,,. Pomess: (Horizon 0).

|
| '
|

A= Abundant.
| 12. Variable

3
| ae 10, Orinoidal 11. Grey) "17 feaaed.
| limestones. | oolite. | sae ee |
! estones. —
Corals :-—
| Michelinia grandis M*Coy ............ xR x ae
| Syringopora ef. distans Fischer ...... x x ys
Syringopora ef. reticulata Goldfuss . x re . ae
| Caninia cylindrica (Secouler), Salée. . D4 xB I xR
Cyathophyllum » Vaughan ............ | x xA | 4
| Lithostrotion martini Edwards &
We. GE AMEE Sade ae oo ee ena ee ue xR KA
| Carcinophyllum mendipense Sibly ...' oe Pete: < | x |
Brachiopods :— | ' |
| Small pustulose and punctate Pro- | |
DUWIGIIC + =>. 0 Gene A Ee |
| Productus cf. concinnus Sowerby ... x ee
|Productus corrugato - hemisphericus /
Vaughan (including Pr. aff. cora /
D’Orbigny and Pr. @ Vaughan) ... x XA | xA
| Chonetes ef. hardrensis Phillips ...... * a: ) ome
| Papilionaceous Chonetes ... ........... ~ | XA XA
| Chonetes carinata Garwood (=Ch. :
destinezi Vaughan) ................0 4 | ie ar
Schellwienella ef. crenistria (Phillips) xA Kaa ps

Camarophoria isorhyncha (M‘Coy)... va a xR
Small Rhynchonellids, including |
Rkynchonella cf. angulata (Lin- |

| GUS et es 23s tee) Peo ee ee aa =

Small Spirifers, including Spirifer ef. :

purcapus MSC Oy. trot ae x x | x

| Syringothyris ef. cuspidata (Martin). = x | e:
| Spiriferina cf. laminosa M‘Coy ...... ae yn ep
| Seminula ef. ambigua (Sowerby) ... XA x on
| Seminula ficoides Vaughan ............ x x x

Athyris ef. eepansa Davidson, non
(. Gbulligg) Po sey sae ee eee xA x x
| Athyris ingens De Koninek............ AG ge xB |
|Reticularia aff. lineata (Martin), | :
” Werughian 2,3 PPE Sa ee Bae x |
| Gasteropods :— |
| Rehierop iow x t0ii2. 2.2004 Sete x ya x

POM DTUGAES 53 x oss fst eek tan ins een Sek x x x

characterized in the district here described by the abundance of
Productus corrugato-hemisphericus and the common occurrence
of Carcinophyllum throughout, the maximum of Cyathophyl-
lum , and the appearance of abundant Lithostrotion in the upper

va ie Ee
part 2] CARBONIFEROUS LIMESTONE OF S. WALES COALFIELD. 148

. In so far as Upper C, and 8, can be separately distin-
guished, Group 11, with Syringothyris cf. cuspidata and abundant
Cyathophyllum , represents Upper C,; while Group 12, with
abundant Lithostrotion, represents 5..

Westwards from the Ely valley, the sequence in the
standard limestones of C, and S,, so far as it can be determined,
appears to persist to the extremity of our district without sub-
stantial modification ; but, owing to the absence of exposures, the
S, limestones of Group 12 have not been traced much more than
half-a-mile west of Miskin.

Eastwards from the Ely valley, the crinoidal limestones of
Group 10 have not been recognized east of Croftau, but higher
beds, still preserving the character of limestones with an abundant
standard fauna, are exposed a mile and a half farther east, in
Creigiau Quarry. In the distance of 2} miles from Creigiau
Quarry to the Taff, exposures are poor, and throw little light on
the lateral change which converts almost the whole of C, and §,
into a nearly-barren series of dolomites in the Taff
valley.! The characters of the series on the eastern side of the
‘Taff gorge are described on p. 150.

It remains to specify the chief exposures of the standard
limestones of C, and 8, in the outerop west of the Taff. The
exposures will be taken in order from west to east, and descriptions
confined to a statement of horizon (except where special features of
lithology or fauna call for notice).

Old Quarry (Glam. 41 SW \ 2), on the north side of the road 300 yards

south-west of Pont-y-Rhyd, on the western side of the Dawen valley: appa-
_ rently the base of the grey oolite 11, with the topmost beds of the underlying
crinoidal limestones 10.

Crags extending eastwards from the hamlet of City, north of Llansannor,
and terminating on the west in a quarry behind the City Inn: the grey
oolite 11, highly crinoidal.

Quarry (Glam. 41 NE \ 7), in Coed-y-Fforest, south of Llanharry Station :
a good exposure of the crinoidal limestones of Group 10, seen to a thickness
of nearly 100 feet. Some shaly partings and dolomitic beds, and some
breeciation due to contemporaneous erosion. Caninia cylindrica is common,
Michelinia grandis occurs, and Chonetes cf. hardrensis is abundant.

Old Quarry at the roadside 450 yards west of the last-named quarry: the
grey oolite of group 11.

Old Quarry (Glam. 42 NW \ 10), at the southern end of Coed Gellihir-ganol,
between Brynsaddler and Miskin: the junction of crinoidal limestone and
oolite, at the top of 10 and base of 11.

1 fA recent examination of the old workings of the Garth iron-mine has
revealed two bands of oolite within the contemporaneous dolomites that
underlie the Seminula Oolite in Garth Wood. Both these oolite-bands have
suffered very extensive subsequent dolomitization. The lower band may
represent either the Caninia Oolite or some part of C,. The upper band can
be assigned without doubt to C,+S,: it is probably identical with the band,
shown in our diagram of the Taff's Well and Tongwynlais sequence (vertical
sections, fig. 2, p. 119), of which evidence is furnished in C,+S, on the eastern
side of the Taff gorge by surviving patches of unaltered oolite (p. 159).
T. F.S., July 4th, 1918. ;

14-4 MR. F. DIXEY AND PROF.T. F. SIBLY ON THE [vol. Ixxii,

Old Quarry (Glam. 42 NW A 9), north of Ty-isaf, and 500 yards east of the
last-named exposure: mainly in the crinoidal limestones of Group 10, but
the base of the overlying oolite just appears. The crinoidal limestones
contain many dolomitic bands, in one of which casts of Productus corrugato-
hemisphericus are numerous. The great abundance of Seminula ef. ambigua
in one bed recalls a level in Lower C, of Burrington Combe, Mendips.

Old Quarry (Glam. 42 NW \ 11), in Coed Gellihir-uchaf, north of \ 10: the
westernmost exposure of the 8, beds of Group 12. Very variable crinoidal
and oolitic limestones in frequent alternation, with lateral change from one
type of rock to the other. The uppermost beds are extraordinarily fossili-
ferous, and formed largely by masses of Lithostrotion martini: they yield
Carcinophyllum mendipense, Camarophoria isorhyncha, and Athyris ingens,
an assemblage which recalls the ‘ Milton-Road level’ in 8, of Weston-super-
Mare and the Mendips.! ;

Quarry (Glam. 42 NW X 2), a quarter of a mile north of Miskin: this quarry
illustrates the sequence of the three groups recognized in the
standard limestones of C, and 8, (see photograph, Pl. XIV). Extending
for more than 200 yards along the strike, it affords an admirable exposure of
the beds. The section includes the uppermost beds of the crinoidal lime-
stones of Group 10, seen to a thickness of 20 to 30 feet: the whole of the
grey oolite of Group 11, 40 to 50 feet thick; and about 25 feet of beds
belonging to Group 12. The beds assigned to the top of Group 10 are dark-
grey crinoidal limestones, with shale-partings, yielding Cyathophyllum @
among other fossils. The grey oolite 11. and the thinly-bedded limestones of
Group 12, exhibit their typical lithology and fauna (described on pp. 140—
43). More than half-way up in the oolite isa band of thinly-bedded, black,
gasteropod-limestone, with abundant Bellerophon: this is conspicuous in the
photograph(Pl. XIV) as « projecting rib. Current-bedding and contemporaneous
brecciation are particularly conspicuous in the uppermost part of the oolite.
A thin smut-band,? of carbonaceous shaly matter, up to 8 inches in thick-
ness, rests upon an apparently-eroded surface of the oolite, and separates
this from the thinly-bedded limestones of Group 12. These latter beds inelude
a band of pink marl with distorted lamination. and a thick bed of marly
limestone.

Quarry (Glam. 42 NW X 1), lying immediately west of the last-named: the
grey oolite and the base of Group 12.

Old Quarry 100 yards north of the Castell-y-Mynach Arms, near Croftan :
a section in the crinoidal limestones of Group 10.

Small excavation (Glam. 42 NW A 19), 300 yards north-east of the Castell-
y-Mynach Arms, near Croftau: crinoidal limestones of Group 10, vein-
dolomitized in part, and including a 12-inch band of dolomite-mudstone.
Chonetes carinata oceurs, in association with Syringothyris ef. cuspidata.

Creigiau Quarry (Glam. 42 NE 4): the great thickness of oolites and
oolitic limestones here exposed probably belongs mainly to C,—S,, repre-
senting Group 12 of the Miskin sequence. The lower beds yield Lithostrotion
martini (abundant) and a large Caninid (rare) among many other fossils.
Complex faulting and extensive vein-dolomitization have affected the highest
beds of the quarry, which probably represent the base of §.,.

Main Seminula Gone: 8p.

The appearance of Cyrtina carbonaria marks the base, and the
occurrence of the Dibunophyllum fauna detines the top, of S,. . It

1 T. F. Sibly, Q. J. G.S. vol. lxi (1905) p. 560, and A. Vaughan, ibid,
vol. lxvii (1911) p. 370.

2 Compare the smut-beds in the Lower Dibunophyllum Zone of Gower :
R. H. Tiddeman. ‘The Country around Swansea’ Mem. Geol. Sury. 1907,
pp. 10. 11; also E. KE. L. Dixon, Gower paper, p. 490.

oi ae
part 2] CARBONIFEROUS LIMESTONE OF 8S. WALES COALFIELD. 145

is only in the outcrop west of the Ely, however, that the overlying
beds of the Dibunophyllum Zone occur, East of the Ely, the top
of 8, is overstepped by the Millstone Grit.

The main Seminula Zone maintains a constant character from
the western end of the district here described as far as the river
Taff, except for the fact that its basal beds have become dolomites
in the Taff valley.

Lithology.—Two divisions can be recognized, but they pro-
bably pass insensibly one into the other ! :-—

14. Modiola phase with much standard limestone. Extra-
ordinarily varied in details of lithology. Modiola-phase deposits,”
namely, calcite-mudstones including white-weathering ‘ chinastone-
limestones’ with conchoidal fracture, and limestones with pisolitic
and pseudo-concretionary structures, alternate repeatedly with, and
pass into, standard limestones which are essentially oolitic, shelly,
and crinoidal. Bands of fairly-pure oolite are not infrequent.
Pisolitie structures are abundantly developed: they are often, but
not invariably, accompanied by brecciation due to contemporaneous
erosicn. .

13. Seminula Oolite: essentially, grey oolites and oolitic
limestones of standard type, but including some very subordinate
Modiola-phase deposits resembling those of the overlying group.
Current-bedding and the development of contemporaneous breccia-
tion are occasional, .

Thickness.—Between 500 and 600 feet, of which the Mod/ola
phase forms less than 200 feet.

Fauna.—Fossils of the standard groups, brachiopods, corals,
and erinoids, are quite as abundant and varied in the Modiola
phase as in the Seminula Oolite. They are, however, notably less
common in the caleite-mudstones and certain other less fine-grained
limestones developed in the Modiola phase; in these beds,
Seminula ficoides is almost the only abundant form. In the
Modiola phase, the rock-types just mentioned, and also the piso-
litie beds with their numerous standard fossils, often contain
Serpula.

Gasteropods, including Bellerophon, Euomphalus, and Lowo-
nema, are sometimes common.

Corals :—
Alveolites septosus (Fleming), Edwards | Lithostrotion martini Edwards &
& Haime. Haime.
Syringopora ct. distans Fischer. Lithostrotion (Nematophyllum)
Syringopora cf. geniculata (Phillips), minus, M‘Coy.
Edwards & Haime. Carcinophyllum vaughani Salée (C.8

Vaughan).

' Compare Mr. Dixon's description of S, in the eastern district of Gower ;
Gower paper, p. 488.

2 For the general characteristics of the S, Modiola phase, see EB. EB. L.
Dixon, Gower paper, p. 514.

146 MR. F. DIXEY AND PROF. T. F.SIBLY ON THE [vol. xxii,

Brachiopods :—
Papilionaceous Chonetes. Schellwienella ef. crenistria (Phillips).
Productus corrugato-hemisphericus Cyrtina carbonaria M‘Coy.
Vaughan. Seminula ficoides Vaughan.
Productus hemisphericus J. de C. | Athyris ef. expansa Davidson, non
Sowerby. ‘ (Phillips).

On the whole, corals and brachiopods are not abundant, much of
the Seminula Oolite being poor in macroscopic organisms. But
beds crowded with Seminula, Productus, or Chonetes are fairly
frequent. Lithostrotion martini is seldom abundant. Careino-
phyllum vaughani may occur commonly at any level in the zone.
Nematophyllum minus is only found near the base, while Alveo-
lites septosus anda large form of Productus hemisphericus become
abundant near the top.

Following are notes on the best exposures of the 8, beds,
taken in order from west to east :—

Many exposures of beds in the upper part of S, occur in the outcrop from
Ruthin to Llanharry: among them are the following :—

Old Quarries (Glam. 41 NW 2 2), immediately east of the Roman Camp,
south of Ruthin.

Old Quarries near Gelligarn Castle, in Coed Breigam, about a mile east
of Ruthin.

Exposures immediately south and east of Llanharry village :—

Quarry (Glam. 41 NE 5), 300 yards south, a little west, of St. Illtyd’s
Church.

Old Quarry (Glam. 41 NE ) 4), 300 yards east of St. Illtyd’s Church.

Quarry (Glam. 41 NEA 2), at the roadside east of the village, and 500 yards
west of Llanharry Station.

Old Quarry (Glam. 41 NEA 3), 230 yards south-south-east of St. Illtyd’s
Church.

All the exposures specified above, except the last-named, exhibit the highly-
variable beds of the Modiola phase. The last-named exposure shows a
crinoidal oolite with abundant brachiopods, which may he either within, or
just below, the Modiola phase.

In the same district, the followimg are the chief exposures of the Seminula
Oolite :—

At Craig-yr-Hos, on the southern side of Mynydd Ruthin: a level near the
top of the Seminula Oolite.

Old Quarries lying south and east of Argoed-isaf,a mile and a quarter
south-west of Llanharry : horizons rather low in the Seminula Oolite.

The Llanharry Limestone Company’s Quarry (Glam. 41 NE 1), east of
Llanharry, and 500 yards south-west of Llanharry Station. This gives an
extensive section. The rocks are oolites and oolitic limestones, poorly fossili-
ferous on the whole. Some bands of calcite-mudstone are developed.

Old Quarry (Glam. 41 NE A 6), on the west side of the road, 300 yards south-
west of the last-named quarry: thickly-bedded, grey, crinoidal oolite which
must lie very near the base of S,. Fossils are abundant. Some bands are
crowded with Productus corrugato-hemisphericus or Seminula ficoides, and
both Cyrtina carbonaria and Carcinophyllum vaughani (2) occur commonly.
Nematophyllum minus has been found at this locality only.

Between the exposures near Llanharry, just described, and the ground
north of Creigiau, a distance of 4 miles, the only good exposure of beds in
the Main Seminula Zone is that afforded by the Bute Quarries (Glam. 42 NW
X 3), half a mile north-east of Miskin. These quarries lie in the Seminula
Oolite. They expose thickly-bedded grey oolite, with a small development of

part 2] CARBONIFEROUS LIMESTONE OF 8S. WALES COALFIELD. 147

psendo-concretionary structures, and some bands of chinastone-limestone, the
latter containing seams crowded with Seminula ficoides.

In the disturbed ground adjacent to the Creigiau Fault, the Seminu/a Oolite
is found to be much ironstained and almost wholly vein-dolomitized, as shown
a little west of the fault by a railway-cutting a third of a mile north of
Creigiau Station, and on the eastern side of the fault by crags on the steep
hillside below Coed-y-Creigiau. The highest beds of Creigiau Quarry, much
fault-shattered and dolomitized, probably belong to the basé of the Seminula
Oolite. .

Half a mile north-east of Creigiau an old quarry (Glam. 36 SE 7) lying
100 yards north-north-west of Pen-Llwyn exposes highly fossiliferous beds of
grey oolite and oolitic limestone, overlain by dark limestones with beautifully
developed pseudo-concretionary structures. This section appears to lie
within the Seminula Oolite.

The Modiola phase of 8, is evidenced by many small exposures along the
outcrop extending from the Creigiau Fault to Pen-y-garn and farther east. The
most easterly exposures occur at the roadside 500 to 900 yards east-north-east
of Capel-Horeb, Pen-y-garn: they show oolitic and compact nodular lime-
stones, with abundant Seminula.

In the Taff valley, Cwarre Glas (Glam. 36 SE (3), on the steep north-
- eastern slope of Garth Wood (PI. XIII, fig. 1), is a long-disused, picturesque
quarry in the Seminula Oolite: vein-dolomitization is very extensive here.

An old quarry in the woods 450 yards south-west of Cwarre Glis shows
dark-grey finely-oolitic limestones overlying coarse oolite. This probably
represents the top of the Seminula Oolite.

Below the Seminula Oolite of Cwarre Glas lies the monotonons series of
crystalline dolomites which form the bulk of the Main Limestone in the
Taff valley. On the evidence of fossils found on the opposite side of the
gorge (p. 150) the topmost portion of this dolomite series is of 8S, age.

Lower Dibunophy/llum Zone: D,.

The beds assigned to this subzone contain a characteristic
assemblage of corals with Déhunophyllum 0, Carcinophyllum
ala and Cyathophyllum murchisoni as essential members.

e Dibunophyllum beds ave apparently confined to: that part
of the district which lies west of the Ely river. They have not
been traced farther east than the ground immediately north of
Brynsaddler, in the Ely valley, and in all probability their base is
overstepped by the Millstone Grit in the drift-covered area north
of Brynsaddler.

Around Ruthin, in the extreme west of the district here described,
persistent northerly dips over a wide outcrop indicate a thickness of
about 600 feet of limestone above the Seminula Zone, before the
Carboniferous Limestone finally disappears beneath the Keuper on
_ the north. Of this thickness, about 450 feet can be assigned to D.
on conclusive faunal evidence : higher beds in the Ruthin outerop
may belong either to D, or to D,, but the fossils which have been
yielded by the meagre exposures of these beds are of no zonal value.

Lithology.—Chietly grey crinoidal and shelly limestones,
often highly ery stalline, and occasionally oolitic. A’ characteristic
feature in this district, as in Gower and elsewhere, is the extenswe
development of pseudo-brecciated structures! in the limestones.

! First described by Mr. R. H. Tiddeman, * The Country around Swansea’
Mem. Geéol. Surv. 1907, p. 10.

148 MR. F. DIXEY AND PROF. T. F. SIBLY ON THE [ vol. xxii,

The pseudobreccias, like those of Gower, are highly foraminiferal.
The peculiar structure of these rocks, which has been attributed
by Mr. E. E. L. Dixon! to the patchy and early recrystallization of
a calcareous mud, results in a characteristic honeyeomb-weathering.
Beds of red-stained, rubbly limestone are associated with the
pseudobreccias. At a high level in the subzone are developed
some dark-grey fine-grained limestones, approximating to calcite-
mudstones ; they contain Calcisphera ( ?) and many foraminifera.

Fauna:

Corals and brachiopods :—

Syringopora spp.—a 4. | Productus hemisphericus J. de C.
Alveolites septosus (Fleming), Edwards Sowerby.—a 4, 5.
& Haime.—. 4. | Productus ef. giganteus (Martin).—
Cyathophyllim murchison Edwards | A 3,4.
& Haime.—A3,A4,A5. | Papilionaceous Chonetes.— 8, 44,5.
Lithostrotion irregulare (Phillips).— | Spirifer cf. striatus (Martin).—\* 4
\ 3, A 5. / (rare).
Inthostrotion martin Edwards & Martinia glabra (Martin).—A 4 (rare).
Haime.—\ 3. _ Cyrtina septosa (Phillips).—a 4.
Carcinophyllum vaughani Salée.— | Seminula ficoides Vaughan.—A 9, \ 4,
X3,A4. he pears

Dibunophyllum 9 Vaughan.—a 8, Xd 4, | Athyris cf. expansa Davidson, non
A 5. | (Phillips).—A 4, r5.

A 3, 4, and \5 are localities near Ruthin, in the 6-inch sheet Glamorgan
41) NW, to be described immediately.

The following are the best exposures of the D, beds in the
outerop around Ruthin :—

Quarry (Glam. 41 NW A383), immediately north of the Roman Camp, Ruthin.
This exposes a level at or very near the base of the Dibunophyllum Zone.
The rocks are highly-crystalline grey limestones, in several beds of which
Dibunophyllum @ is extremely abundant.

Old Quarry (Glam. 41 NW 4), 100 yards north of Tyle-gwyn, west of
Ruthin. This section, lying much higher in the subzone, shows pseudo-
breccias and rubbly limestones.

Exposures (Glam. 41 NW 5), on the northern edge of Coed Garwa, east
of Ruthin.. These show highly-fossiliferous beds of pseudobreccia, rubbly
limestone, and finely-saccharoidal grey limestone. One band has yielded
pygidia and a cranidium of Griffithides sp.

Hast of a point about midway between Ruthin and Llanharry,
the D, beds, in so far as they have not been overstepped by
the Millstone Grit, are almost wholly concealed by Keuper and
Glacial drift. But a small, disused quarry, at Llechau Farm, half-
way between Llanharry and Brynsaddler, has yielded Dibunophyl-
lum @ and Lithostrotion irregulare ; and the spoil-heap of an
eae iron-mine situated north-west of Brynsaddler, and about
100 yards south-east of Ty-du Reservoir, contains blocks of grey
erinoidal limestone which have yielded Dibunophyllum 4. These
are the most easterly indications of the Dibunophyllum Zone.

Gower paper, pp. 507-11.

>

«
»
] CARBONIFEROUS LIMESTONE OF 8. WALES COALFIELD. 149

East of the Taff.

The Main Limestone is better exposed than in the area west of
the Taff. But the overstep of the Millstone Grit, which has
already progressed below the top of S,, cuts out the whole of that
zone before the Ebbw valley is reached, while dolomitization and
the development of Modiola phases obliterate so much of the
faunal succession that only two zonal horizons (Z, and the base of

S,) can be traced.

No trace of the C, fauna has been found, and only vestiges of the C,+5,
fauna. It has not been possible, therefore, to define a boundary between
C, and C.. The line drawn on our map (Pl. XVI) does not, however,
represent a conjectured zonal boundary. From Cefn-carnau-fawr, about 2
miles east of the Taff, to Pen-how, 1 mile west of the Rhymney, it is a definite
lithological division-line. It marks the base of a band of crystalline dolomites,
of C,+8, age, which becomes defined, as we proceed north-eastwards, by the
appearance of underlying and overlying argillaceous Modiola phases. This
dolomite-band must be assigned to C,+S, from its position in the sequence,
which can be determined accurately at Thornhill and on Cefn-On (p. 151).
But considerations of thickness indicate also that some part of the underlying
Modiola phase belongs to C,, and lead to the conclusion that this Modiola
phase is of C,-C, age. In the central portion of the outcrop between the
Taff and the Rhymney, therefore, the line drawn on our map separates an

gi Modiola phase of C,-C, age from a band of crystalline dolomite
belonging to C,+S,. West of Cefn-carnau-fawr, and east of Pen-how, it
represents merely the conjectured position of the same level. The argil-
laceous group ceases to be recognizable a little west of Cefn-carnau-fawr,
while the dolomite-band appears to. die out and give place to argillaceous
beds east of Pen-how.

The Main Limestone on the eastern side of the Taff gorge.

Almost the whole thickness of the Main Limestone is exposed
in quarries and railway-cuttings on the eastern side of the Taff
gorge! The cuttings on the Cardiff Railway, together with
Castell-Céch Quarry and Portobello Quarry, afford a section which
is practically continuous from the base of the Main Limestone
almost up to the top of the Seminu/a Oolite ; while the Barry
Railway, which has crossed the gorge on the Walnut-Tree viaduct,
cuts into the C,+8, beds and provides a duplicate section from this
latter horizon upwards (see photograph, Pl. XIII, fig. 1).

The succession may be tabulated as follows :

Feet.

Ss Oolite and oolitic limestone iighe

‘ eS a Pepe © ee Athen: 1220
C,+58, \

Cc, Dolomites ...... , . 1250
“Z 3

OUME. sae eas .. 1760

——

The Z, fauna is poorly represented, and traces of the C,+5, fauna
are found. The S, fauna is well represented, and the base of 3,

! The suecession is briefly described in the Newport Memoir, 2nd ed. pp. 20,

24-25.

150 MR. F. DIXEY AND PROF. T. F. SIBLY ON THE (vol. Ixxiii,

has been drawn at a level marked by the appearance of Cyrtina
carbonaria.+

The estimates of thickness should be regarded as rough approxi-
mations, except in the case of the S, dolomites, the thickness of
which can be determined with fair accuracy. Allowance has been
made for some probable repetition, by thr usts, of beds within the S,
oolites. Both the dolomites of Z—C, and the oolitic beds of 8, are
much broken and sheared, doubtless owing to the close pr oximity
of the sections to the great dip-fault which runs along the gorge.
The dip varies from aa 60°, slightly west of north, in the lower
beds, to about 20°, north-westwards, in the upper part of S,,.

Calcite-veining on both a large anda small scale is greatly developed

throughout, and nests of calcite and dolomite are ‘abandante in the
dolomites generally. Although the dolomites are mainly contem-
poraneeus, portions of the sequence, in C,+8, and in S. owe their
dolomitie character to vein-dolomitization. The problem of the
dolomitization is not discussed here, however.

Castell-Céch Quarry (Glam. 37 SW 25), a great quarry which extends
almost as far north as the Walnut-Tree viaduct, exposes the grey finely-
crystalline dolomites which form the lower half of the Main Limestone.
These beds cover Z and probably the whole of C,. As mentioned on p. 131,
the section includes the junction of the Main Limestone with the Lower
Limestone Shales, and this junction is sharp. The basal beds of the Main
Limestone are grey or buff-coloured argillaceous dolomites, with some very
thin’ shale-partings. They include some richly-crinoidal seams, and show a
small development of crinoidal chert. Their horizon (Z,) is indicated by an
abundance of Productus burlingtonensis, associated with Schellwienella cf.
crenistria and Syringothyris cf. cuspidata, observed on a shaly bedding-
plane.

Beds assignable to C,+S, are exposed (a) in the low-level cutting of the
Cardiff Railway, under and immediately north of the Walnut-Tree viaduct,
and (b) in the high-level cutting of the Barry Railway. In the main, these
are grey or yellow, fine-grained to medium-grained dolomites, barren of fossils.
They include occasional bands of dolomite-mudstone and lenticles of clay,
features which foreshadow the strong development of Modiola-phase deposits
farther east. They have yielded a few fossils. On the Cardiff Railway,
Syringopora ef. reticulata (2?) and Productus corrugato-hemisphericus have
been recorded. On the Barry Railway (Glam. 37 SW A 6), about 110 yards
from the viaduct wall, a band of yellow dolomite contains colonies of
Lithostrotion martini with the tissue completely dolomitized. This band les
about 35 feet below the base of S,. Patches of slightly-dolomitized, pale-
grey oolite survive in a massive dolomite exposed on the Cardiff Railway
65 yards north of the viaduct. This is the easternmost trace of the normal
oolites of C,+8, discovered in our district.

The dolomites which form the lowest part of S, are best exposed on the
Barry Railway (Glam. 37 SW 6). They are grey slightly-crinoidal rocks,
fine-grained to medium-grained, and thinly bedded, with occasional clay-
partings. At their base, Cyrtina carbonaria and Seminula ficoides are
represented by numerous casts in a band of dark-grey dolomite, red-stained
in patches. - This band, defining the base of S,, lies 140 yards from the wall
of the Walnut-Tree viaduct, on the eastern side of the cutting. Except in
this basal band, fossiis other than crinoid-ossicles are rare in these dolomites.
Productus sp., Seminula ficoides,and Carcinophyllum sp. have been identified.

1 Here, as elsewhere east of the Taff. the dolomites with Cyrtina car-
bonaria which form the lowest part of S, represent the basal portion of the
Seminula Oolite as developed farther west.

part 2] CARBONIFEROUS LIMESTONE OF 8. WALES COALFIELD. 151

The passage into the overlying oolites is well exposed in the same cutting.
No definite division-line can be drawn, because dolomitization has affected
the basal portion of the oolite very extensively, spreading not only in veins
along joints, but also in masses which involve the body of the rock.

The Barry Railway also affords a good section of the oolites ; but these
beds are even better displayed in Portobello Quarry, which lies between the
two railways, and in the cuttings on the Cardiff Railway. They exhibit the
typical lithology and fauna of the Seminula Oolite, although everywhere
veined by dolomite and calcite. In the northern portion of each railway-
section the beds are much shatter-jointed and traversed by occasional
faults, probably thrusts. The following corals and brachiopods have been
recorded :

—
.

Syringopora sp. Caninia sp.; rare.
Lithostrotion martini. Productus corrugato - hemisphericus ;
Lithostrotion (Nematophyllum) common.

minus (lower beds only); rare. Papilionaceous Chonetes ; common.
Carcinophyllum sp. Seminula ficoides ; abundant.

Northwards, the section of Carboniferous Limestone terminates in the
Seminula Oolite on both railways. On the Cardiff Railway, limestone
extends to the end of the cutting, where the ground falls abruptly to an
alluvial terrace. On the Barry Railway, the limestone-section terminates
within the cutting, at the point where a bridge crosses, and the rest of the
cutting lies in Glacial gravel. Glacial drift probably covers about 100 feet of
S, beds at the top of the Main Limestone in this locality. The northernmost
exposure of limestone is a small outcrop in a lane immediately east of the Barry
Railway, 65 yards south of Ty-rhiw.' The rock is an oolitic limestone containing
comminuted shell.

The Main Limestone east of the Taff gorge. |
.

As explained in the general account of the succession (§ LV,
pp. 122-23) and illustrated by the vertical sections (fig. 2, p. 119),
the Main Limestone, when traced north-eastwards from the Taff
valley, undergoes three important changes, namely (1) the loss
of S, in consequence of overstep by the Millstone Grit, (2) the ;
attenuation of the surviving zones, and (3) the great development
of Modiola-phase deposits in C-S,.
Abundance of exposures enables us to establish the succession of
beds in considerable detail at Thornhill, and again in the vicinity
of Cefn-On Farm, 1} miles east-north-east of Thornhill. There is
little change between these points. The Cefn-On sequence, which
is illustrated by a horizontal section (fig. 4, p. 120) and by a vertical ;
section in fig. 2 (p. 119), may be tabulated to provide a basis for the }
description of the Main Limestone between the Taff and the Ebbw.

The Main Limestone of Cefn-On.,

Feet. .
(iii) S$, (basal beds of). Dolomites with a band of oolite Loge 3° ae |
Modiola phase (S,) .....-.0:c.c cee cenceeceeeee ees 50
(ii) C,+8,. qe ee dolomite and dolomitie limestone ; |
Re Ce ee ee ee |
©, (part of) ......... Modlala phase (O,-Oy), | .cedebewiiies.s2i..se. 9D
‘4 5 P a age } Dolomites, with some chert near the base ... 450
at calcite 920
—w

1 There is no exposure at the point, 25 yards south-west of Ty-rhiw,
rae, by a dip-arrow on the 6-inch Geological Survey map (Glamorgan,
SW).

152 MR. F. DIXEY AND PROF.'T. F. SIBLY ON THE [ vol, lxxin,

In this sequence the divisions (1), (11), and (iu), and the sub-
divisions of (ii), are well-defined lithologically. The zonal correla-
tion of the S, beds is placed beyond question by the oceurrence of
Cyrtina car bona za and other fossils, but that of the underlying
beds is inferred from considerations of thickness, in comparison
with the faunal succession established west of the Taff.

These three divisions of the Cefn-On sequence may be con-
veniently adopted for the remaining description of the Main
Limestone.

(i) The crystalline dolomites of Z-C,.

In the Taff valley, these dolomites probably cover the whole ‘of
Zand C, (p. 150). Eastwards, the upper beds pass laterally into
Modiola-phase deposits. Asa result of this circumstance, com-
bined with actual thinning of the strata, the thickness diminishes
from about S00 feet in the Taff valley to 400 feet in the Ebbw
valley.

In general, the rocks are grey finely-crystalline dolomites.
Nests o plene and dolomite are sometimes abundant. Chert is
usually developed at or near the base. Oolite, completely dolomi-
tized, is developed in considerable thickness, less than 100 feet
above the base, in Cefn-garw Quarry and in an adjacent disused
quarry, and has been observed at the same horizon in the scarp-
face of Cefn-On.! Fossils, other than ecrinoid-débris, which is
generally distributed and sometimes abundant, are usually rare.
At two localities to be described, however, they occur abundantly
at and near the base ; and at various levels and localities Scheli-
wienella cf. crenistria and Spirifer clathratus have been observed.
Excellent exposures are afforded by Cefn-garw Quarry, north of
Tongwynlais; Gelli Quarry, north of Rhubina ; quarries at Thorn-
hill; crags and cuttings on Cefn-On; Machen Quarry; and Dan-
y-Graig Quarry, Risca.

Cefn-garw Quarry (Glam. 37 SW X 2), situated 750 yards east-north-east
of Castell Céch, gives an admirable section of about 60 feet of beds lying
very near the base of the Main Limestone. The lower beds of the quarry
are blue-black, buff-weathering, crinoidal dolomites of very fine grain. The
middle beds are pale to dark-grey richly-crinoidal dolomites. These
latter are characterized by a highly-irregular development of black argil-
laceous streaks, by extensive silicification resulting in patches of crinoidal
chert and occasional nodules of chalcedony, and by an irregular patchy iron-
staining. They resemble closely the crinoidal liznestones which form the
base of the Main Limestone west of the Taff (p. 135). Their correlation
with Z, (Horizon /3) is determined by the following fossils found in them :—

Zaphrentis delanouei (?). Camarotechia mitcheldeanensis
Chonetes cf. hardrensis ; common. common,

Leptena analoga ; common, Spirifer clathratus.
Schellwienella ef. crenistria; common. | Syr ingoth yris cf. cuspidata.

Spir iferina octoplicata, mutation /3.

! Specimen E 7423 in the collection of the Geological Survey, obtained
from the lower part of the Main Limestone east of the Ebbw river at Risca,
is a dolomitized oolite of identical character. See Newport Memoir, 2nd ed.
Plate, fig. 5 (microphotograph).

1538

The upper beds of the quarry are grey crinoidal dolomites, highly
oolitic in some beds, and containing Schellivienella ef. crenistria and Spirifer
clathratus.

In the Rhymney valley, a cutting on the Brecon & Merthyr Railway
(Mon. 27 SE \1), immediately below Machen Quarry, exposes the base of
the Main Limestone. The section shows 8 or 10 feet of thinly-bedded, dolo-
mitie limestones, with some highly argillaceous bands and an abundant
development of crinoidal chert, underlying grey dolomites without chert.
The change from the argillaceous, cherty beds to the normal grey dolomite
is sharp. - The lowest bed exposed is a band of dark-grey crinoidal limestone,
slightly cherty but non-dolomitic, and containing Chonetes ef. hardrensis and
Chonetes crassistria Vaughan (non M‘Coy) in profusion, together with Spirifer
clathratus and Schellivienella cf. crenistria.

The grey dolomites of this railway-cutting and Machen Quarry show none
of the special features of the beds in Cefn-garw Quarry, described above.
In Dan-y-Graig Quarry, Risca, the base of the Main Limestone, again
exposed, shows fine-grained dolomites alternating with hard dolomitic shales,
and the beds contain only some scanty crinoid-débris. There is evidently
much variation in the character of the lowest beds of the Main Limestone
between the Taff and the Ebbw.

(ii) The Modiola phases, ete., of C-S..

The sequence clearly defined on Cefn-On, comprising two
Modiola phases with an intervening band of crystalline dolomites,
can be traced for about 2 miles along the outcrop in each
direction, west-south-westwards to the neighbourhood of Cefn-
carnau-fawr, and east-north-eastwards to the vicinity of Pen-how.
Along this portion of the outcrop a colour-boundary on our map
(Pl. XVI) represents the base of the dolomite-band, as explained
on p. 149. Farther west, the MJodiola phases cease to be traceable.
Farther east, the dolomite-band has not been recognized: and,
by the time the Rhymney valley is reached, the whole division
has probably assumed the essential character of a Modio/a phase,
which it presents in the Ebbw valley.

On the eastern side of the Rhymney valley, in the ravine below
Ffwrwm, the Millstone Grit oversteps the base of S., and comes to
rest directly upon the C-S, beds. This sharp transgression, which
is associated with the development of a band of quartz-conglo-
merate at the base of the Millstone Grit, continues as far as the
crest of the ridge between the Rhymney and the Ebbw, and so
cuts out a considerable thickness of C-S, beds. On the descent to
the Ebbw River, however, the quartz- -conglomer: ate dies out, the
.base of the Millstone Grit retrogresses, and the-upper beds of C-S*
emerge almost completely.

The lower Modiola phase (C,-C,) is by far the thickest
group, and attains a thickness of some 250 feet on Cefn-On. It
is composed largely of dolomite-mudstones, very varied in colour,
with thin partings and lenticles of shale and clay, and a consider-
able intercalation of very fine-grained, crystalline dolomites. In
the middle and upper portions, compact grey limestones, mostly
caleité-mudstones with conchoidal fracture, may be developed in
large or small amount. No fossils have been observed.

154. MR. F, DIXEY AND PROF. 't. F. SIBLY ON THE | vol. Ixxi,

On the dip-slope of Cefn-On, about 200 yards west of the line of the
Caerphilly Tunnel, the southern quarry in some old workings (Glam. 37 NW
A. 1) affords a good exposure of the uppermost beds. These are dolomite-
mudstones, with some dolomitic shale in the lower part and a regular inter-
calation of finely-crystalline dolomites in the upper part. Some bands of
nodular dolomite-mudstone in the lower beds contain calcitic patches. The
overlying crystalline dolomite comes on in the northern part of these workings
(see below).

In the Cefn-On Farm traverse (horizontal section, fig. 4, p. 120), the lower
beds of the group are exposed in a cutting on the cart-road, 120 yards north-
north-west of the farm. These are dolomite-mudstones with a little purple-
and-green shale and afew bands of crystalline dolomite. Another cutting,
70 to 80 yards farther north on the cart-road, exposes dark-grey calcite-
mudstones, with platy bedding and shale-partings, which lie about the middle
of the group.

Many small exposures occur in the neighbourhood of Maenllwyd, east of
Rudry. A well-developed dry valley marks the outcrop of the group north
and north-east of the Maenllwyd Inn. An old quarry on the northern side of
this valley, situated 130 yards north-north-west of Tir-Sion-Philip-Morgan,
exposes beds near the top of the group, compact limestones and fine-grained
dolomites with some shale and marl.

The band of erystalline dolomite and dolomitic
limestone (C,-S,), which can be traced from Cefn-carnau- fawr
to Pen-how, gives rise to a well-marked feature along much of this
distance. Its thickness amounts to 120 feet or more at Thornhill,
and to about 100 feet on Cefn-On. It includes rocks which vary
much, as regards both size of grain and degree of dolomitization.
Fairly-pure dolomites predominate, but a considerable amount of
partly-dolomitized limestone is also found. Dolomitized oolite
occurs in small amount on Cefn-On. Fossils, other than erinoid-
ossicles, have been found at one locality only, on Cefn-On.

On Cefn-On, in the old workings (Glam. 37 NW \ 1) which lie 200 yards
west of the line of the Caerphilly Tunnel, the northern quarry, much over-
erown, exposes the lower beds of this group. The rocks are grey saccharoidal
dolomites, coarse-grained for the most part, but including some fine-grained
bands. On the cart-track which skirts this quarry, some bands of fine-
grained dolomite have yielded Bellerophon, Schellwienella cf. crenstria,
Seminula sp., and crinoid-ossicles, all preserved as casts or moulds.

The upper Modiola phase (S,) is a very variable group
averaging roughly 50 feet in thickness. The rocks are mainly
calcite-mudstones and dolomite-mudstones, or closely - similar
compact limestones and dolomites!; but they also comprise some
medium-grained oolites and some persistent beds of crystalline
dolomite. In all these, very fine quartz-sand, in small or moderate
amount, is ubiquitous. Thin shale-bands are frequent.

Unmistakable vein-dolomitization has everywhere affected the
limestones to some extent, and in places it has produced an
extensive conversion of limestone, amorphous-looking in its original
state, into coarsely-crystalline dolomite. This is well seen in
stream-sections on both sides of the Rhymney valley: on the

1 Types covered by Mr. E. E. L. Dixon’s description of ‘ Calcite-mudstones
and similar rock-types, Gower paper, pp. 516-17.

q

2) CARBONIFEROUS LIMESTONE OF 8. WALES COALFIELD. 155

poh

western side, in the woods west of Rhyd-y-Gwern, and on the

eastern side, in the ravine west-south-west of Ffwrwm.

In the limestones, ostracods and Calcisphera (7) are sometimes
abundant, crinoid-débris and foraminifera oceur more sparingly,
and serpulids occur rarely. ‘The fauna is, therefore, decidedly that
of a Modiola phase.'

This Modiola phase is immediately overlain by the dolomites
with Cyrtina carbonaria which represent the base of §,. Its
zonal horizon (S,) is, therefore, quite definite. As far east as
Pen-how its base is defined by the underlying band of crystalline

‘dolomites ; but farther east, where that band dies out, it forms

merely the uppermost part of the very thick Modiola phase of
C,-S, age in the Rhymney and Ebbw valleys.

The best sections are afforded by (1) an old quarry (Glam. 37 NE 2X1)
situated about midway between Pen-y-waun and Pen-how, north-east of
Rudry, and (2) the stream-bed and banks in the ravine (Mon. 27 SE \ 2)
immediately west-south-west of Ffwrwm, on the eastern side of the Rhymney
valley. At the first-named locality, dolomite-mudstones and crystalline
dolomites predominate over calcite-mudstones. In the Ffwrwm ravine,
dolomites are subordinate to a variety of calcite-mudstones and other fine-
arma limestones, while a thick band of dark-grey oolite forms a conspicuous
eature.

In the Ebbw valley, the C.-S, Modiola phase, apparently
unbroken, attains a thickness of about 275 feet. It is sueceeded
directly by the shales of the Millstone Grit,’ but the junction is
not now exposed. The strata, poorly exposed in the cutting on
the railway east of Waun Fawr Brickworks, are chiefly dolomite-
mudstones, with much very fine-grained crystalline dolomite and
some coarsely-crystalline dolomite. Very near the Millstone-Grit
boundary, near Buck Farm on the hillside south of the railway,
some small outcrops of smooth-textured oolitie limestone, contain-
ing ostracods, suggest the S, horizon of the ravine below Ffwrwm
in the Rhymney valley.

(iii) The 8, beds.

It has been seen (p. 149) that the 8, beds on the eastern side of
the Taff gorge comprise some 130 feet of dolomites succeeded by
nearly 400 feet of oolites and oolitic limestones. At Pen-y-bryn,
a mile away to the north-east, dolomites about 150 feet thick
alone represent S,. This rapid apparent thinning can only be
explained by overstep of the Millstone Grit. Kast-north-eastwards
from Pen-y-bryn to the Rhymney valley, the dolomites of §,
diminish but gradually in thickness, for they amount to 100 feet
at Thornhill, 60 feet or more on the dip-slope of Cefn-On, and
probably 50 feet in the Rhymney valley. On the eastern side of
that valley, however, they are cut out by a sharp transgression of
the quartz-conglomerate at the base of the Millstone Grit.

1 See E. E. L. Dixon, Gower paper, pp. 518-19.
2 Newport Memoir, 2nd ed, p, 21.

Q. J. G.S. No, 290. .

156 MR. F. DIXEY AND PROF. T. F. SIBLY ON THE [vol. lxxiu,

These basal beds of S, are grey crystalline dolomites, fine-grained

or medium-grained. Being much more resistant to denuding
agents than either the underlying J/odzola phase or the overlying
shales of the Millstone Grit, they give rise to a conspicuous
feature along much of their outcrop. ‘They can readily be mapped,
and at many points they have yielded the characteristic brachiopod
Cyrtina carbonaria and other fossils.

In Fforest Fawr and the woods adjacent to it on the north, are a few
exposures of the S., dolomites and many of the overlying oolites. The latter
beds are extensively vein-dolomitized in mass, and often rendered highly
ferruginous by the development of hematite. An old quarry beside the road,
immediately south of Pen-y-bryn Cottage, gives a small exposure of ferruginous
erinoidal dolomites containing Cyrtina carbonaria.

The following tabular list of fossils records most of the fossiliferous
exposures of the S, beds in their outcrop from Pen-y-bryn to the Rhymney
valley.

Locality.
Genera and species. | 7
| 1 | 2. | 8i) dea) ea aie
pag |
SU MUnG OPORG BPs .6a2 ccc. aon oye ue ee ee | XX |. eee
| Lithostrotion martini Edwards & Haime.| Xo 1 XM La
| Curcinophyllum sp. .......20.....0.ce eee So" 36 x
| Productus corrugato - hemisphericus
Tabsiag WELTY AEUTA e e.c 2sty i cite ae hg OU UE Bet | Mee oj 5b oe
| Cyrtina carbonaria M‘Coy ............... x | X | % | genes
Seminula ficoides Vaughan ..:............| X |X| % | See ee

1. Old Quarry (Glam. 37 SW X 7), 350 yards north-west of Cefn-
carnau-fawr.
2. Old Quarries (Glam. 37 SW A 8), immediately south-east of
Ty’n-y-ton, north of Thornhill.
3. Old Quarries (Glam. 37 SW AY), immediately west of Cefn-
carnau-uchaf, north-north-east of Thornhill.
4. Bed of lane (Glam. 37 NW \ 2), on the northern side of Cefn-On,
a quarter of a mile west of the Caerphilly railway-tunnel.
5. Old Quarry (Glam. 37 NE \ 3), in woods north of Cefn-On Farm,
200 yards east-north-east of Ty’n-y-pare.
6. Footpath (Glam. 37 NE A 2), 100 to 150 yards north-east of
Pen-y-waun, north-east of Rudry.
. Stream-bed (Mon. 27 SE A 2), about 100 yards west of Ffwrwm,
eastern side of the Rhymney valley.

~J

In all cases except one, the fossiliferous beds are grey dolomites. The
exception is afforded by the old quarry (Glam. 37 NE 2 3) near Ty’n-y-pare,
where a band of coarse-grained white oolite yields the fossils. This oolite
is probably succeeded immediately by the Millstone Grit.

Below Ffwrwm in the Rhymney valley, where the 8, beds are last seen,
they crop out in the stream-bed and in the very steep northern side of the
ravine, and they are seen to overlie the Modiola phase of S,. About 30 yards
upstream from their last outcrop, a band of quartz-grit crosses the stream-
bed; and the quartz-conglomerate, of which this grit probably forms the
basal bed, undoubtedly cuts out the S, dolomites in this locality.

iad mt

part 2] CARBONIFEROUS LIMESTONE OF 8S. WALES COALFIELD. 157

VI. SumMMARY AND CONCLUSIONS.

Summarizing the results of our investigation of the changes
which affect the Carboniferous Limestone Series when traced
north-eastwards along its outcrop between Bridgend and Risca, we
find that :—

(1) The diminution in thickness is due only in part to actual
attenuation of the strata, a factor of greater importance being the
overstep of the Millstone Grit across successively lower horizons in
the Carboniferous Limestone.

(a) Unconformable overstep by the Millstone Grit cuts out the Dibuno-
phyllum beds and the Main Seminula Zone (S,), the collective thickness of
which in the extreme west of the outcrop amounts to some 1200 feet.

(b) Actual attenuation diminishes the collective thickness of the surviving
zones——K (Lower Limestone Shales), and Z to 8, (Main Limestone)— by some
700 feet, from about 1500 feet in the west to 800 feet in the east.

(2) The Lower Limestone Shales maintain their lithological and
faunal facies substantially unaltered.

(3) The zones of the Main Limestone which persist throughout
(Z to §,, inclusive) undergo great changes in lithological and faunal
character.

(a) In the Taff valley, the sequence of undolomitized limestones with
subordinate dolomites which obtains in the west has given place to an
almost unbroken succession of dolomites. This is due to a progressive
increase in the vertical extent of contemporaneous dolomitization. The
faunas, although largely obliterated, maintain a standard facies.

(b) East of the Taff valley, the lower beds (Z—C) maintain the character
of crystalline dolomites with remnants of the standard fauna. The upper
part of the sequence (C-S,), however, becomes a Modiola phase of great
thickness, composed essentially of dolomite-mudstones with subordinate
calcitic beds.

Our investigations confirm, therefore, the opinion previously
expressed by Mr. E. E. L. Dixon! that unconformable overstep by
the Millstone Grit takes place in this part of the coalfield margin.
The discordance of stratification between the Carboniferous Lime-
stone and the Millstone Grit is probably so slight that it would
be inappreciable in sections of the junction of the two formations.
None the less, the indisputable overstep of the Millstone Grit
across a large part of the Carboniferous Limestone Series admits
only of the conclusion that the junction is a true plane of uncon-
formity, determined by a period of uplift and denudation during

- which the beds of the Carboniferous Limestone were shaved off

obliquely from the north-east or north, Outside the district
here described, several facts suggest that the area of maximum
uplift at the time of this earth-movement lay to the north-east,
rather than to the north. The attenuation of the Carboniferous
Limestone Series continues northwards along the eastern margin
of the coalfield, as far as a point near the north-eastern corner of
the basin: west of that point, however, the Series thickens rather

' Newport Memoir, 2nd ed. p, 20,

158 . MR. F. DIXEY AND PROF.T. F.S{BLY ON THE [vol. lxxii,

rapidly along the ‘north crop’ of the coalfield! Further, ‘ Mill-
stone Grit’ overlies Carboniferous Limestone unconformably in the
Chepstow? district, east of the area here described; and Coal
Measures succeed the Lower Carboniferous strata with pronounced

_ unconformity in the Forest-of-Dean Coalfield,? lying to the north-

east. It is very probable that the unconformity now shown to
exist on the eastern fringe of the South Wales coal-basin was
due to the earth-movement which produced a great break in the
: is

Carboniferous succession of the Forest of Dean.

No detailed comparison of the variable succession in the district
that has been described in this paper with the Avonian of other
areas need be made, but attention may be directed to a few points
of interest.

The sequence in the westernmost part of our district, although
probably lacking the highest portion of the Avonian, parallels the
succession in Gower very closely in other respects. But the
remarkable dolomitic sequence in the extreme east of the district
here dealt with cannot be matched elsewhere in the South-Western
Province: its nearest analogue, to be found in the Forest-of-Dean
succession,” presents considerable differences.

The interval of Avonian time, K to 8S, inclusive, is represented
by deposits which survived the inter-Carboniterous denudation
everywhere in the district here described.

K. The slight variation of the deposits of this zone throughout

the district accords with the general constancy of facies shown
by. the K beds throughout the South-Western Province. But the
attenuation of the beds in a north-easterly direction indicates
that subsidence was more rapid in the south-west than in the
north-east.
’ Z to §,. The changes of facies and the attenuation of the strata
from south-west to north-east indicate (1) that the area of deposit
shallowed, as a rule, in a northerly or north-easterly direction, and
(2) that subsidence was more rapid in the south-west than in the
north-east. The form of the outcrop—a single band trending
north-north-eastwards—precludes any discrimination, on local
evidence; between the significance of northerly or north-easterly
directions in this connexion.

In the interval represented by Z, yC,, and the Laminosa Dolo-
mite the north-eastward shallowing was probably slight, the change
of facies amounting to no more than an increase of dolomitization.

In the interval represented by the Caninia Oolite and C,+8,, how-
ever, standard conditions prevailed almost or quite ® continuously

‘ +The Country around Abergavenny’ Mem. Geol. Surv. 1900, p. 19.

2 At Ifton (Monmouthshire): E. E. L. Dixon, Geol. Mag. dec. 5, vol. vi
(1909) p. 515.

3 T. F. Sibly, Geol. Mag. dec. 5, vol. ix (1912) pp. 417, 420-21.

4 EK. E. L. Dixon & A. Vaughan, Gower paper. See especially p. 505 and
pp. 532-37 ; and compare table (p. 505) with our table on p. 118.

> 'T. F. Sibly, Geol. Mag. dec. 5, vol. ix (1912) pp. 418-20.

6 The thin Modiola phase developed at the base of C, at Miskin has not
been detected farther west.

a e'|. ae

part 2| CARBONIFEROUS LIMESTONE OF S. WALES COALFIELD. 159

in the south-west of the district here described, while lagoon
conditions prevailed without sensible interruption in the north-east.

The thick, dolomitie Modiola phase of C.—-S, which is developed
in the easternmost part of the district agrees, in all its essential
features, with the JJodiola phase of C,-S, which succeeds the

-Caninia Oolite in the Avon, Sodbury, and Tytherington sections

of the Bristol area! to the south-east and east. In the district
here described, however, the phase, commencing in C,, probably
covers the period of the Caninia Oolite.

EXPLANATION OF PLATES XII-XVI.

Pear Sou

Fig.1. Craig Llanishen, Cefn-On, and the intervening strike-
valley: view looking westwards. The features of the middle
distance, etc., reading from left to right, that is, from south to
north, are as follows:—(a) the wooded crest and dip-slope of
Craig Llanishen—the quartz-conglomerate and sandstones of the
Upper Old Red Sandstone; (b) a grassy belt—-the highest beds
of the Old Red Sandstone and the limestones and shales (1) of
the Lower Limestone Shales ; (c) a wooded ridge—the limestones
(2) of the Lower Limestone Shales; (d) a grassy belt—the shales
(3) of the Lower Limestone Shales ; and (e) the wooded scarp and
crest of the western end of Cefn-On—the Main Limestone. See
map (Pl. XV1I).—T. F. Sibly, photo.

2. The scarp-face of Cefn-Onat the head of Cwm Draethen:
view looking eastwards. The features of the middle distance and
foreground, reading from left to right, that is, from north to south,
are as follows :—(a) the steep, wooded scarp of the Main Limestone ;
(b) a grassy flat, made by the shales (3) of the Lower Limestone
Shales ; (c) a low, wooded escarpment, made by limestones in the
Lower Limestone Shales ; (d) the ravine of the Draethen brook,
cut in the topmost beds of the Old Red Sandstone ; and (e) the
dip-slope of Craig Lysfaen—Upper Old Red Sandstone. The
features (a), (b), and (c) are displaced in this locality by a dip-
fault, the track of which enters the picture at the lower right-hand
corner and runs up a ravine in the scarp-face of the Main
Limestone. In the distance, the Main Limestone escarpment and
the high ridge of Craig Ruperra (Old Red Sandstone) appear
faintly. See map (Pl. XVI), and section (fig. 4, p. 120).—
T. F. Sibly, photo.

3. Machen Quarry, etc.: view looking north-eastwards across the
Rhymney valley. The crystalline dolomites forming the lower
part of the Main Limestone, in which the quarry is opened,
determine a bold wooded ridge. The scarp-face of this ridge
falls southwards to (1) a grassy flat, succeeded by (2) a low,
wooded ridge, the two features so often caused by the shales and
limestones respectively, of the Lower Limestone Shales (compare
figs. 1 & 2). The dip-slope of the ridge falls northwards to a
cultivated tract which is made by the C,—-S, Modiola phase of
the Main Limestone. The Pennant-Grit scarp of Mynydd Machen
enters the left-hand side of the picture. See map (Pl. XVI).—
T. F. Sibly, photo.

1 A, Vaughan, Q.J.G.S. vol. lxi (1905) pp. 1938-95 (Avon), pp. 207-209
(Sodbury), pp. 221-22 (Tytherington).

160 MR. F. DIXEY AND PROF. T. F. SIBLY ON THE [ vol. lxxini,

PuatTe XIII.

Fig.l. The gorge of the Taff below Taff’s Well: view looking
south-eastwards from the eastern end of Garth Hill. The gorge
separates the Carboniferous-Limestone ridge of Fforest Fawr on
the east from that of Garth Wood on the west (map, Pl. XVI).
The wooded dip-slopes of these two ridges appear in the picture.
Beyond Fforest Fawr is seen the ridge of Greenmeadow Wood,
determined by a quartz-conglomerate at the base of the Upper
Series of the Old Red Sandstone. In the foreground, the Taff
valley widens in the strata of the Millstone Grit and the Lower
Coal Series, and receives a tributary strike-valley, cut in these
strata, from the west. In the distance, the limestone-gorge opens
out into the lowlands of Old Red Sandstone which extend south-
wards to Cardiff. Cwarre Glas lies in the Seminula Oolite (p. 147).
The quarries and cuttings on the eastern side of the gorge expose
almost the whole of the Carboniferous Limestone Series (pp. 128,
130, 131, & 149-51).—F. Dixey, photo.

2. The escarpment of the Main Limestone, Garth Wood:
view looking westwards, across the southern end of the Taff gorge,
from the hill above Tongwynlais (map, Pl. XVI). Ty-nant Quarry
(pp. 1386 & 138) is seen at the foot of the escarpment. The
Lower Limestone Shales lie buried under drift at the foot of the
escarpment.—F. Dixey, photo.

PLATE XIV.

General view of a quarry in ©,-S, beds, a quarter of a mile
north of Miskin. This quarry (Glam. 42 NW X 2) illustrates
the sequence of the three groups, 10, 11, & 12. recognized in the
standard limestones of C, and S, near Miskin. (See p. 144.)
T. F. Sibly, photo.

PLATE XV.

Geological map illustrating the Carboniferous Limestone Series between the
Ewenny valley and the Taff valley, on the scale of 2 inches to the
mile, or 1: 31,680.

PLATE XVI.

Geological map illustrating the Carboniferous Limestone Series between the
Taff valley ad the Ebbw valley, on the scale of 2 inches to the
mile, or 1 : 31,680.

DISCUSSION.

Dr. A. SrraHan expressed the pleasure with which he saw the
details being filled into the outlines which he and his colleagues
had drawn many years ago.. Part of the outcrop described by “the
Authors presented exceptional difficulties, for the lithological types
were abnormal and fossils were scarce. It would be interesting to
see how zones had been mapped under such conditions. It had
been known from the first that the limestone series became greatly
diminished in thickness from south to north or north-east ; Taal it
had long been a matter of discussion how far this was Fie to an
originally meagre development, and how far to overlap by the
Millstone Grit. There are, in places, indications of erosion of the
limestone-surface below the basal conglomerate of the Millstone

Quart. Journ. Geol. Soc. Vol. LXXIII, le bap We

Fig. 1.—Craig Llanishen, Cefn-On, and the intervening
strike-valley : looking westwards.

Fig. 2.—The scarp-face of Cefn-On at the head of

Cwm Draethen: looking eastwards.

Fig. 3.—Machen Quarry, etc., looking north-eastwards
across the Rhymney Valley.

T. F. Sibly, photo.

Quart. Journ. Geol. Soc. Vol. LX XIII, Pl. XIII.

Fig. 1.—Gorge of the Taff, looking south-eastwards
trom Garth Hill.

Castell Coch Cwarre Glas.
&
Castell Coch Quarry.
| TONGWYNLAIS.
j

GARTH
Woop.

Fig. 2.— Escarpment of the Main Limestone, Garth Wood ;

looking westwards.

F, Dixey, photo.

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Quart. Journ. Geol. Soc. Vol. IXXM PLAK

INDEX

Old Red.
Sandstone

Main Rf 30, ip of Sti ‘
Timnestone >” i ¥ ‘onountin ora,
=

GEOLOGICAL Map
ILLUSTRATING THE avium Peat,
Terrace Gravel

CARBONIFEROUS LIMESTONE SERTES
BETWEEN fe ieasicnd
| tHE EWENNY VALLEY ano tHe TAFF VALLEY SS renper. ie
GEOLOGICAL LINES FROM THE PUBLISHED MAPS OF THE GEOLOGICAL SURVEY, |)» |@az Tech tee
ices balla Sie

WITH MODIFIGATIONS,AND ZONAL SUBDIVISIONS OF THE CARBONIFEROUS LIMESTONE SERIES, [ fistne stan I< Zonven
[Whale Grit j dimastone NA B Line of Section.

By FRANK Di xXeEy, M.Sc.F.G.S. ¢
UNIVERSITY COLLEGE OF SOUTH WALES AND MONMOUTHSHIRE, CARDIFF. Scale, 2inches = 1 mile

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Glam 47K. \
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Geol. Soc Vol. LXXUL, PLXVI,

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ILLUSTRATING THE

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CARBONIFEROUS LIMESTONE SERIES

BETWEEN THE TAFF VALLEY & THE EBBW VALLEY [D|@@2easures
GEOLOGICAL LINES FROM THE PUBLISHED MAPS CF THE GEOLOGICAL SURVEY, |____|Sadstone
WITH MOD|FICATIONS, AND ZONAL SUBDIVISIONS OF THE CARBONIFEROUS LIMESTONES SERIES, (ies Shale
BY T. FRANKLIN SIBLY, D.Sc., F.G.S., ¢
University Cortece of SoutH Wares & MonmouTHsnike,CarDIFF.

GEOLOGICAL MAP Byes

et hea

Mee
iy.
WZ Fforest Fawr

y ‘ < Rhubing. F
/ TONGWYNLAIS = S_@
Sta Greenmeadow:
s Wood: i

umstone

[ purea Sandstone

SY Dip of Stratawith
anountin degrees.

—-— Vertical strata.

——-—Ffaults.

Fossil Localities, ctr. 5

tidica led thus = Glam 37SHANF

A——B Tine of Section \~
— We

Di

eries

Carboniferous
BY

HSC.Graham US Lith? Lon.S.B.

part 2] CARBONIFEROUS LIMESTONE OF §. WALES COALFIELD. 161

Grit, as in the example figured in the Abergavenny Memoir; and,
indeed, it was difficult to see how such an area could be invaded by
currents strong enough to distribute coarse gravel without some
washing-up of the sea-bottom. The matter was complicated by
the piping of the limestone, which had taken place on so great a
scale as to eventuate in wholesale subsidence of the Millstone Grit
and to cause difficulty in mapping its base. He was not satisfied
that there was evidence of an unconformity of a pronounced order,
such as would involve the supposition of ‘upheaval and prolonged
denudation.

All the Carboniferous subdivisions shared in the attenuation,
clearly indicating the existence of Carboniferous land at no great
distance to the north. The shore-line appeared to have run ina
direction generally parallel to the existing margin of the Coalfield.
Part of the margin of the Carboniferous Limestone could be
recognized in Pembrokeshire, and eastwards near the Welsh Border.
The different aspects under which the limestone presents itself at
various distances from the shore-line afford an unrivalled opportunity
of studying the types developed under littoral conditions, such as
dolomites, oolites, pisolites, interbedded conglomerates and others.
He looked forward to the prosecution of researches on which so
promising a commencement had been made.

Mr. E. E. L. Drxon said that he would refer to two points only.
The more important was the overstep of the Millstone Grit across
successively lower horizons of the Carboniferous Limestone. This
overstep continues along the outcrop that bounds the eastern end
of the coalfield, north-east of the area described in the paper. For
some miles, however: that is, to beyond Pontypool, it results in little
further thinning of the Lower Avonian dolomites; but, from Cwm
Afon north-eastwards, it rapidly increases and cuts out almost, if not
quite, the whole of the remaining dolomites. Nevertheless the
underlying Lower Limestone Shales maintain their thickness un-
changed, and present the same rock-types and the same fauna,
indicative of the Clezstopora Zone, as elsewhere along the outer op.
There can be no doubt that they do not represent the Main Lime-
stone + Lower Limestone Shales of other localities.

This is the extreme amount of the overstep. The outcrop here-
abouts swings westwards, and, in that direction, successively-higher
subzones of the Main Limestone emerge from beneath the Millstone
Grit—so rapidly that in less than 6 miles appear several hundred
feet of limestone, in which all the zones, up to the Upper Semnaula
Subzone, §,, are recognizable.

In this area, also, important confirmatory evidence of the uncon-
formable nature of the Main Limestone—Millstone Grit junction
has been obtained, of which details will be published later.
Although no discordance of dip is to be observed in actual exposures
of the junction (which fortunately are to be seen at several places
in this area), the latter is sharp and irregular, and in the largest
exposure, in the Llammarch dingle near Bryn-mawr, is sufficiently
transgressive to cutout 6 feet of ‘limestone in a distance of 35 yards.

162 THE CARBONIFEROUS LIMESTONE [ vol. Ixxiu,

The Carboniferous Limestone also, immediately below the junction,
is penetrated toa distance of several feet below its upper surface,
by pipes and veins of hard grit, pebbly in places, continuous. with
the overlying, evenly-dipping beds of grit but firmly welded to the
enclosing limestone and, on some unweathered surfaces, difficult to
distinguish from it at first sight. It is evident that the limestone
has been eroded subaérially, and the cavities filled with Millstone
Grit. But the even he of the beds of grit above, the consolidated
state (due to siliceous cementation) of the grit-infilling, and the
close union of limestone and infilling make it equally evident that
the grit, both that infilling the limestone and the bedded grit, has
been deposited from the first in the position in which it is now
found. That is, the subaérial erosion of the limestone preceded
the deposition of the grit. The junction is, therefore, truly
unconformable. ©

The other point mentioned by the speaker was the possibility
that knoll-reefs would be found in the Barry area, where, he under-
stood from the Authors, highly-fossiliferous well-bedded limestones
attained a great development. Jor, in a similarly-placed outcrop
in Pembrokeshire, small knoll-reefs had been discovered at about
the junction of the Lower with the Upper Avonian, the adjacent
beds—in fact, the greater part of the Main Limestone—being
highly-fossiliferous well-bedded limestones with the fauna distine-
tive of Zaphrentid phases. Similar phasal deposits appear to be
the invariable concomitants of knoll-reefs.

Dr. T. T. Groom said that the Fellows of the Society would see.
with gratification that the valuable zonal work initiated in the
British Carboniferous Limestone by the late Dr. Vaughan was
being continued by the Authors. As to their application of the —
results to the structure of the Forest-of-Dean Coalfield, the speaker, —
accepting Mr. Kidston’s view that the Middle and Lower Coal ©
Measures were absent from this area (a viewconfirmed by Dr. Arber), |
had, like the latter, inferred the existence of an unconformity ©
beneath the Coal Measures of the basin. But, when Prof. Sibly |
later maintained that this was accompanied by extensive overstep |
within the area, the speaker was unable to agree with him. Heasked
for evidence in support of the statement that such overstep occurred
in the northern part of the basin, and said that, with reference to
the south-eastern side, much of which he had mapped on a large
scale, he had stated that the supposed overstep of the Coal Measures
on to the Old Red Sandstone was due to faulting. He was quite
unable to accept Prof. Sibly’s interpretation of the section in the
Blackpool Valley, where the Carboniferous Limestone dipping at
about 70° was supposed to be directly overlain by gently-inclined jj
Coal Measures. The theory of overstep in this district was beset ||
with difficulties, one of which was that, at the time of the deposition |
of the Coal Measures, the Limestone and associated beds must have
shown over the area of overstep a dip nearly equal to that seen at
the present time ; while the corresponding beds beyond the area were —
still undisturbed: also that the limestone of the patch underwent

part 2] OF THE SOUTH WALES COALFIELD. 165

little further tilting ; while ata later date that along the north-east
side of the basin received a tilt agreeing in amount with the first.
Thus the same continuous limestone-band between Mitcheldean and
the Blackpool Valley, dipping almost uniformly at from 60° to 70°,
must be supposed to have been tilted to the same extent at two
different periods: one part before, and another after, the deposition
of the Coal Measures. The speaker maintained that the field
evidence, part of which was indicated, was decisively in favour of
the view that dip-faults and strike-faults together had produced
the appearances attributed to overstep, and thought that the un-
conformity at the base of the Coa] Measures was probably so gentle
that the dip of these, as seen in single exposures, might not be
visibly different from that of the underlying stratum. He de-
murred, therefore, to the term ‘flagrant unconformity’ employed
in the abstract of the paper.

Mr. F. Drxey, in referring to the very irregular surface of the
Carboniferous Limestone upon which the Millstone Grit rests near
Abergavenny, and to pipes and caverns of Millstone Grit in the
Carboniferous Limestone, mentioned that all the above features,
described by Dr. Strahan and Mr. Dixon as occurring on the
eastern margin of the South Wales Coalfield, are reproduced in
detail near Haverfordwest, on the southern margin of the Pem-
brokeshire Coalfield, where the Millstone Grit rests unconformably
upon the Dibunophyllum beds of the Carboniferous Limestone.

Prof. E. J. Garwoop congratulated the Authors on tue com-
pletion of an important piece of work showing the value of
detailed zoning in the Lower Carboniferous rocks. He commented
on the numerous facts of interest which the paper contained. He
would have liked to ask for further information about some of
the points brought forward; but, owing to the lateness of the
hour, he would confine his observations to the question of the two
periods of dolomitization described by the Authors. In West-
morland the dolomitization of the Lower Limestones in the Shap
district could be proved to have taken place contemporaneously
with the deposition of the beds; but the rocks also contained
cavities lined with crystals of dolomite, which must have been
deposited subsequently to the consolidation of the deposit. In
this case the material for the crystals must have been leached out
of the upper portion of the dolomite and redeposited from solution :
the speaker would like to ask the Authors whether the secondary
dolomitization described by them might not be due to a similar
process, or whether they had evidence that the material which
produced the second dolomitization had been introduced at a
subsequent geological period.

Prot. T. F. Srpty thanked Dr. Strahan, Mr. Dixon, and
Prof. Garwood for their appreciative remarks. Mr. Dixon’s inter-
esting description of the phenomena on the eastern and northern
margins of the coalfield afforded a gratifying confirmation of the
Authors’ conclusions. As to the problem of dolomitization dis-
eussed by Prof. Garwood, the vein-dolomites were developed on too

Q. J.G.S. No. 290. O

164 CARBONIFEROUS LIMESTONE IN SOUTH WALES. | vol. lxxil.

large a scale to be attributed mainly to material leached out of the
contemporaneous dolomites, although some such redistribution of
dolomite had doubtless taken place.

He had not anticipated that this would be made the occasion of
an attack by Dr. Groom upon the interpretation of the succession
in the Forest-of-Dean Coalfield which he (the speaker) had published
more than four years ago. He adhered in every particular to the
conclusions then published. The unconformity was quite unmis-
takable. It was evidenced by continuous transgression of the
Coal Measures across the Lower Carboniferous strata (Carboni-
ferous Limestone and Drybrook Sandstone) on the northern and
eastern borders of the coalfield; by a great difference in the
inclination of the two series of strata all along the eastern margin
from Mitcheldean to Howbeach; and incidentally by marked
angular discordance at the junction exposed in an old quarry
near Howbeach Colliery. Dr. Groom, by admitting the existence
of ‘a gentle unconformity at the base of the Coal Measures,’
invalidated his own objections to the speaker’s interpretation of
the structure. As a fact, the attitude of the Lower Carboniferous
strata determined a change from slight discordance with the .
Coal Measures on the northern edge of the coalfield to pronounced
discordance on the eastern edge. The features in the Blackpool
Valley were due, not to faulting as maintained by Dr. Groom,
but to rapid, unconformable overstep by the Coal Measures. A
mass of further evidence, collected by the speaker since 1912,
could be adduced to confirm his reading of the succession in che
Forest of Dean; but, on account of the lateness of the hour,
he would not pursue the subject further.

[| August 20th, 1918. |

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part 3] THE TRIAS OF NEW ZEALAND. 165:

ya ry ian Pa
7. The Trias of New ZeEatanp. By CHARLES renee" i nsti,

TRECHMANN, D.Sc., F.G.S. (Read February 7th, 1917: >)

[Puares XVII-XXV—Fosst1s.] MAY |
. wv
CONTENTS. De Pig «
Page al |
<. SLIPS CET DUCT Pena A Be i A, cn ae gee -2 165 ean

Me vomenclature and ‘Correlation................:0cc0-26 use oe eee 167

Wt, tathology, Thickness, and Tectomics .............sceceeeeees 170

iMeeneoieal Areas of Triassic Rocks... ....+...:612+20-eyeoneoenot 173.

(1) North Island: Kawhia area.
(2) South Island: Nelson area; Okuku; Mount
Potts; Mount St. Mary; Hokonui Hills;
Kaihiku Gorge; Nugget Point; Moonlight
Range.
ON) LEE E TACO) 72 eee na 181
(a) Cephalopoda.
(b) Gasteropoda, etc.
(c) Lamellibranchiata.
(d) Brachiopoda.
VI. Synopsis of Divisions and Fossils of the New Zealand

Line, ¢ GIES ECT 0a ean ee 237
VII. Relation of the New Zealand Trias to that of New

Caledonia and the Malay Archipelago..................... 237
SPIRE DMO ET ATONE) oie og oon dow ace aedlddg veeilde acd cpaveecdsienecstinge tes ool 239

I. INTRODUCTION.

NEw ZeEawanpd occupies the most isolated and, so far as the
paleontology is concerned, one of the lesser-known links in the
great chain of folded marine Triassic sedimentary rocks which.
surrounds the Pacific Ocean.

The presence of Triassic rocks of the Alpine type in New Zealand.
was first made known as a result of the visit of the Austrian frigate
‘Novara’ in 1858 & 1859 and the researches of F. von Hoch-
stetter. Four species of Triassic fossils found on that occasion were
described and figured by Zittel in 1864.1. These were JlLonotis
salinarva var. richmondiana Zittel, Spirigera wreyt Suess, Mytilus
problematicus Zittel, and Halobia lommeli Wissmann.

The Nelson province was the only district where Hochstetter
obtained Trias fossils. He collected several Jurassic forms at
Kawhia Harbour on the western coast of the North Island, but
the ‘Triassic deposits south of the harbour were discovered ata
later date.

Since Hochstetter’s visit the detailed geological survey of New

1 Bibliography, 51, } p. 26-29.
©&.9.G.S. No. 291. P

—s

166 DR. C. T. TRECHMANN ON [ vol. lxxiu,

Zealand has revealed the wide extension of the Triassic rocks, and
their stratigraphical and tectonic features have in many areas been
more or less satisfactorily worked out.

Sir James Hector! published from time to time lists of the
fossils which the officers of the Survey had collected. His lists
were not accompanied by figures or descriptions, and those from
the beds with which the present paper deals were mostly names of
well-known Huropean Permian and Triassic forms. He paid, how-
- ever, a closer attention to belemnites and brachiopods, and established
three subgenera of the latter: namely, Rastelligera, Psioidea, and
Clavigera, based upon descriptions unaccompanied by figures.” He
caused plates illustrative of these groups to be printed, apparently
intending them to accompany a longer paper which seems never
to have been written. These plates have recently been issued with
the First Paleeoutological Bulletin of the New Zealand Geological
Survey,? and several of the fossils represented have been identified
in the Survey collections. Hector’s three brachiopod subgenera
figure largely in the reports of his colleagues on the Survey; but
their validity is not.generally recognized outside New Zealand, nor
by all geologists in that country. .

Little has been done since then towards an accurate determination
or description of the Triassic and Jurassic fossils, largely, no doubt,
owing to the lack in New Zealand of literature dealing with the
marine Trias of other regions. Prof. P. Marshall+in 1908 published
a description with illustrations. of six species of cephalopods, three
from the Trias of the Hokonui Hills, and three from the Jura of
Kawhia. The paper attracted the attention of G. Boehm, the
specimens were sent.to him, and the result of his examination
of them appeared in 1910.5 A selection of fossils from the old
Survey collections was sent to Behm, but was returned unexamined,
owing to his death in 1910.

My interest in the Trias of New Zealand commenced during the
British Association visit to Australasia in 1914, when I spent about
nine weeks in the country. I was there again in 1915 and 1916,
when I stayed three months, and again visited the chief Triassic
and other fossiliferous localities and made extensive collections. I
also had free access to the old Survey collections preserved in the
Wellington Museum, some boxes of which had never been opened
since they were collected over forty years ago. For this privilege
I am indebted to Dr. P. G. Morgan, the Director of the Survey,
and to Dr. J. Allan Thomson, the Curator of the Dominion
Museum. <A number of selected specimens were sent to England
for me to examine. Prof. Marshall also kindly lent to me several
fossils which he had collected in the Triassic and other rocks.

Special attention was paid to the collection of casts and impressions
from which gutta-percha squeezes could be made, and I have largely

1 Bibliography, 15, Introduction, p. x.
2 Bibliography, 16. 3 Bibliography, 47, pls. i-v..
4 Bibliography, 25. > Bibliography, 7.

part 3] THE PRIAS OF NEW ZEALAND. 167

used this substance during my work on the Triassic fossils, which -
are often unsatisfactorily preserved.

In the present paper forty-six genera of mollusca and brachiopoda
are described, of which three seem to be hitherto undescribed and
are regarded as new, and seventy-eight species, of which forty-one
seem to be new, together with five or six new or local varieties of
species already known. This certainly falls considerably short
of the total which must exist in the New Zealand Trias. There
are several conspicuous fossils which are too badly preserved, or
otherwise unsuitable, for adequate illustration or description ; but I
hope that in the future better-preserved specimens of these and
other forms may be found.

For the zonal divisions I have relied primarily on my own
collecting ; but, where better specimens than those that I found
existed in the Survey collections, 1 have made use of these for
description, though in most cases only where the recorded localities

(=)
are confirmed by my own collecting.

Il. NoMENCLATURE AND CORRELATION.

Great divergence of opinion has existed among New Zealand
geologists concerning the classification of the rock series inter-
mediate between the Reefton and Baton-River Series, which contain
a marine Silurian or Devonian fauna, and the beds commencing
with the Bastion Series which yield a lower Jurassic marine fauna.
Hector classified them as follows in 1886 in his ‘Handbook of New
Zealand Geology.’ In the right-hand column JT add the equivalents
which I suppose these divisions to represent, after my examination
of the faunas.

Higher Jurassic series, with marine faunas

J URASSIC. 8b. Putataka Series. da Idett Ae thie Methuen,

8a. Mataura Series.
$c. Flag-Hill Series.

Rive 9a. Catlin’s-River Series. cane Jurassic beds, with marine faunas of
: 9 b. Bastion Series. Liassic, and probably also of Bajocian age.
Tarés 10a. Otapiri Series. =Rhetic and Upper Noric beds.
Ff 10 b. Wairoa Series. —=Lower Noric and Higher Carnic beds.
lla. Oreti Series. — Lower Carnic beds.

SoeMIAN. 11 b. Kaihiku Series. =Beds with a Ladino-Carnic marine fossil
horizon near the top, and a great thickness
of unfossiliferous beds below, representing
Middle and possibly Lower Trias.

12a. Maitai Series. = Maitai Argillites, with Aphanaia Berice
CARBONI- De Koninck. Gaeta
FEROUS. 12 b. Maitai Limestones. =Maitai Limestone, with brachio- ee:
erous.
pods, etc.
- 13 a. Te Anau Series. Probably in part metamorphosed Maitai

PRVONIAN. 13 6. Kakanui Series. Beds.

-- UPPER a - Me d Silurian or Devonian, horizon not yet deter-

SILURIAN. ie mined. lLimestones with marine fauna.

serpentine.

F. W. Hutton! in 1885 included the Te Anau and the Maitai

! Q. J. G.S. vol. xii (1885) pp. 191-220.
p2

e

168 DR. C. T. TRECHMANN ON - | volslaeannte

in his Maitai Series as Carboniferous and the Kaihiku, Oreti,
Wairoa, and Otapiri in the lower part of his Hokonui System as.
‘Triassic.

Prof. James Park! in 1903 classed Hutton’s Maitai Series as.
Jurassic. However, in 1910” he changed his opinion, and said that
the evidence of the separation of the Te Anau from the Maitai
was far from satisfactory, classing the Maitai limestone as Car-
boniferous. He also identified the Kaihiku as Permian and the
Wairoa and Otapiri as Triassic, and included all the rocks from the
upper part of the Maitai to the top of the Jurassic in his Hokonui
System.

Prof. Patrick Marshall? in 1911 included all the beds, from
Hutton’s Maitai Series inclusive to the top of the Jurassic, in his.
Maitai System, and called them Trias-Jura, regarding them as a
conformable series. ‘The incJusion in recent years of the Maitai
Series in the Trias-Jura or Jurassic is due to the fact that, since the
survey of the Nelson area in 1878, no one had succeeded in finding
either the Paleozoic fossils which occur in the Maitai Limestone of
the Wairoa Gorge, or the large prismatic Jnoceramus-like bivalves.
which exist in the Maitai Argillites at Wooded Peak, 5 miles east .
of Nelson and elsewhere. Fragments of this prismatic shell occur
also in the Maitai Limestone, and led to the assumption that the
rocks containing it were Jurassic. In the Nelson area the Trias.
is evidently separated from the Maitai Series which bounds it on
the east and south-east by a strike-fault or series of faults, and
the Maitai Series is undoubtedly of late Paleozoic age, as the early
surveyors concluded.

Hector’s identification of many of the New Zealand Triassic
fossils with English Permian Zechstein forms led him to place the
Kaihiku and Oreti Series in the Permian, a conclusion which was.
naturally followed by his field-workers on the Survey. He identified
three English Permian species out of a total of seventeen in the
Kaihiku, three out of seven in the Oreti, one out of fourteen in the
Wairoa, and four out cf nineteen in the Otapiri. However, in
the Wairoa and Otapiri Series he records, in addition to his sup-
posed Permian forms, a number of Alpine Triassic fossils. The
following reasons seem to have caused Hector to class the Kaihiku
beds as Permian :—

1 Bibliography, 40, p. 431. 2 Bibliography, 37, p. 51.

3 Bibliography, 22, p. 22.

4 C. T. Trechmann, Geol. Mag. dec. 6, vol. iv (1917) pp. 58-64, Dr. J. A.
Thomson and I were so fortunate as to rediscover in 1915 the fossils in the
Maitai Limestone, and to obtain a few additional unrecorded forms from it :
they are undoubtedly of Permo-Carboniferous age. I also found the large pris-
matic bivalves in the Maitai Argillites at Wooded Peak, and have shown from
examination of the hinges that they are not Inoceramus, but are apparently
identical with Aphanaia De Koninck of the Australian Permo-Carboniferous.
The Permo-Carboniferous of New Zealand differs from that of Australia
in being apparently entirely marine, and in lacking a Glossopteris flora and
glacial beds.

part 3] THE TRIAS OF NEW ZEALAND. 169

A. A Dielasma closely resembling the Permian D. elongata occurs in them.

B. He identified the Rhynchonellids of the Halorella group with the
Permian genus Camarophoria.

©. He compared the alate Spiriferine with the Permian Spirifer alatus,
which is not a Spiriferina, but a true Spirifer devoid of punctate shell
or median dorsal septum. Even Prof. C. Diener was not certain on
this point, and speaks of Spiriferina alata.!. The error is due to King,
but was corrected by Davidson.

D. The Spiriferine of the group of Sp. fragilis bear a certain resemblance to
the Permian Spiriferina cristata.

E. The flat dorsal valve of a spiny Mentzelia, to which I have given the
generic name Mentzeliopsis, seems to have suggested to Hector the
genus Streptorhynchus, which appears in his list of Kaihiku fossils. I
myself thought when I collected it that it was some Paleozoic survival,
until, after I had ground down a specimen with both valves conjoined,
the spiralia in it became apparent.

Hector and others sometimes speak of the whole or part of the
Otapiri Series as Rhetic. As there is apparently a perfectly
conformable passage from the Wairoa to the Bastion Series, the
intermediate beds may by analogy be called Rhetic. But, on an
examination of the fossils, the correlation seems to be valid also
on paleontological grounds. The large specialized Spirigerid to
which I have given the new generic name Hectoria shows decided
affinities with the Alpine Rheetic form Spirigera oxycolpos Kmm-
rich, the largest and latest of the Alpine Spirigerids.

Briefly stated, the following are the points in which the results
of my work contrast with the previous views on these beds :—

a. The great unfossiliferous series beneath the lowest fossiliferous horizon
in the Kaihiku represents the Middle and possibly part of the Lower
Trias. It is possible, though very unlikely, that some fossils will in
future be found in the Kaihiku Series below the above-mentioned
horizon.

b. The Kaihiku fauna, the lowest fossiliferous Mesozoic horizon in New
Zealand, is either Upper Ladinic or Lower Carnic —that is, late Middle
or early Upper Trias, and not Permian, as was hitherto supposed.

¢. The higher fossiliferous horizons, which are always separated in clear
sections by several hundred feet from that of the Kaihiku, are all
Upper Trias. The Oreti and lower part of the Wairoa are Carnic, and
yield a prolific fauna. The upper part of the Wairoa and lower part of
the Otapiri are Noric, and contain Psewdomonotis in great abundance.
The remainder of the Otapiri is Rhetic.

d. The only forms that seem to survive the Trias, and may be identical
with Triassic species, are a form of the Spirigerid genus Hectoria and
some of the belemnites of the Atractites group, the large phragmocones
of which occur in the Jurassic beds.

e. I found no fossil in the New Zealand Trias that could be identified
with any English Permian species, so many of which occur in Hector’s
lists.

f. I can see no reason why any of the New Zealand Triassic forms should be
regarded as local isolated survivals from Paleozoic times, as has some-
times been suggested.” The fauna is a normal Upper Triassic one,

1 Bibliography, 11, p. 2. ? Bibliography, 37, p. 69.

/

170 DR. C. T. TRECHMANN ON [vol. lxxiil,.

comparable in every way with faunas of similar age in the great.

circum-Pacific region. Itis now well established that Trigonia and
belemnites of the Atractites and Aw!acoceras group are normal associates

in the marine Triassic beds with such Palzeozoic survivors as Orthoceras

and Dielasma. It is the association of Paleozoic survivals with the

Mesozoic forerunners which gives a special interest to the Trias..

Such archaic survivors at the present day as exist in New Zealand are

chiefly fcund in tke terrestrial fauna and flora owing to its long isola-

tion as a land-mass.

g. There is no premature appearance of truly Jurassic forms in the New
Zealand Trias. The supposed Gryphzea* which has been mentioned

in this connexion is a shell allied to that called Mytilus problematicus..

lil. Lirgotoey, THickNnEss, anD TECTONICS.

The Trias consists of a great series of coarse or fine felspathic:

sandstones, grey or dark shales, and argillites—some very hard,
others, when weathered, of a splintery or crumbling nature, fre-

quently enclosing concretions. Thick beds of coarse conglomerate,.

more or less discontinuous and lenticular, appear at various horizons.

Thin bands of pebbles also occur in the felspathic sandstones and
- wae
greywackes. Prof. Marshall? has examined the pebbles composing
some of the conglomerates, and notes the absence of schistose
rocks. They are made up of granitic or porphyritic fragments.

with felspar- and quartz-pebbles.

The Rhztic beds become more pebbly and glauconitic and less.
felspathic, approaching in character the overlying Jurassic series.

t=)

In some beds the quantity of felspar is so great that the rock
weathers along the joint-planes in large spheroidal masses, and has

given rise to the term ‘cannon-ball sandstone.’ Iron-stained beds.

containing plant-remains occur interbedded with the marine series
at several places.

No definite assertion can yet be made as to the source whence the

material of the Trias was derived, but there was evidently some large

land-mass not far away. ‘The series seems to agree closely with.

the littoral facies of the Trias on the south-western coast of New
Caledonia. The littoral nature of the sediments explains the
absence or rarity of certain fossils, such as ammonites and corals.
Except in the Okuku district, where diabasic ash-beds are reported

to occur (but these, if re-examined, would probably turn out to:

be felspathic sediments), no contemporaneous igneous rocks are
known in the Trias. A dyke occurs at Nugget Point,? and a
hypabyssal intrusion at Kawhia*; Lut these are probably of
post-Jurassic age. |

No natural base of the Trias is seen in any of the localities.

described, although in the Takitimu Mountains, west of the
Hokonuis, the Kaihiku is said to rest unconformably upon the
Maitai Series.°

1 Bibliography, 22, p. 22. 2 Bibliography, 23.
3 Bibliography, 45. + Bibliography, 30.
> Bibliography, 15, Introduction, p. xii.

part 37 THE TRIAS OF NEW ZEALAND. ties

Prof. Marshall estimates the thickness of the rocks from the
top of the Baton-River Series to the top of the Jurassic, his
Maitai System, at 53,200 feet. This includes the Upper Palzo-
zoic, Triassic, and Jurassic strata. Prof. Park reckons the thickness
of the Trias and Jura at 18,000 feet. When I was at Nugget
Point I stepped out the series of the fossiliferous Trias exposed
there, from the Rhetic beds northwards to the road leading to
the lighthouse where the Kaihiku fauna is said to occur. The
beds are tilted on end, and the section is clear; but the Noric
Pseudomonotis Beds are missing. I estimated the thickness at
wel] over 3000 feet. Prof. Park’s diagram of the Nugget-Point
section includes a part of the unfossiliferous Kaihiku and all the
fossiliferous Trias, and the thickness is about a mile. At Kawhia
the Rheetic alone is over 3000 feet thick.

All rocks in New Zealand older than the Cretaceous are affected
by the great orogenic pressure which occurred between the upper-
most Jurassic and the Middle Cretaceous.!. The Trias, except on
the west side of the Hokonui Hills and immediately south of
Kawhia, stands everywhere nearly or quite vertical.. The Jurassic
beds, as a rule, dip much less steeply. The schistosity of much
of the metamorphic rock of the Southern Alps appears to have been
produced during this period. Some of these metamorphic and semi-
metamorphic rocks are undoubtedly Mesozoic, others are Maitai or
pre-Maitai. Greywackes associated with the Trias pass gradually
into phyllites and schists. The change has been described by
Prof. Marshall,? who states further that the schists pass gradually
into the gneisses of Westland. The semi-metamorphic slaty
argillites at Mount St. Mary, which are full of crushed and dis-
torted Triassic fossils of Kaihiku or Ladino-Carnic age, contain
secondary macroscopic flakes of white mica parallel to the
foliation.

1 The history of New Zealand as a land-surface dates from about the time
of the final break-up of Gondwanaland, and its uplift may be connected with
that event. In connexion with the age of the Maitai Series, I have shown
that the New Zealand area was under water during the Permo-Carboniferous
Period. The Jura-Cretaceous uplift is not connected with the present con-
figuration of New Zealand, except that the rocks then hardened and meta-
morphosed resist weathering better, and now form the Alpine Ranges. It was
probably reduced to a low elevation before late Cretaceous times. No part of
the present New Zealand can be said with certainty to have remained land
during Tertiary times. The present uplift dates from the Middle or late
Tertiary, and was more of an epeirogenic nature accompanied by block-fracture.
Tertiary strata are deeply involved in faults, overthrusts, and downthrows in
the Alpine and other areas, but in no case are they much crushed or meta-
morphosed.

2 Bibliography, 21, p. 21.

Fig.1.— Locality
sketch-map of
New Zealand.

A
‘ et ND

Waikatofp SiN

Albatross Point-@Kawhia Harbour

WELLINGTON

NELSONcRichmond
Watroa Gorge

Eighty Hight Valley

‘2
SV" Mt Potts CHRISTCHURCH

Mt.St.Mary
aS

Moonlight Range

Hokonui Hills

Otamita r
Caroline Kaihiku/Gorge .

Scale of Miles
Nugget Point roo

At Kawhia, on the western coast of the North Island, folded Triassic and
Jurassic rocks are exposed beneath horizontal Tertiary covering deposits. At
Waikato Jurassic of undetermined age occurs. Only the Rhetic and Noric
beds of the Trias are known as yet in the North Island.

In the South Island, in the Nelson district, the Trias is much faulted and
folded, and strikes more or less north-north-eastwards and south-south-west-
wards—-parallel to the main structural axis. In the far south it is much
less faulted and disturbed, and the strike of the Trias and Jura from the
Hokonui Hills past Kaihiku Gorge to the coast at Nugget Point is approxi-
mately west and east to west and south-east, at right angles to the strike in

part 3] THE TRIAS OF NEW ZEALAND. 173

IV. Typtcant AREAS oF TrIAssic Rocks.

Fossiliferous Triassic beds are exposed at intervals, from Kawhia
on the western coast of the North Island to Nugget Point on the
south-eastern coast of the South Island, a distance of 620 miles
or nearly 9° along the meridian. The most important localities
are briefly described in the following order :—

District. Chief fossiliferous localities and the horizons represented.

Norta Isuanp.
Raraiie, Coast-section south and south-west of Kawhia Har-
; bour, towards Albatross Point (Noric and Rheetic).
SoutTH ISLAND.
Richmond (Noric); Wairoa Gorge (Carnic) ; Garden
Gully (Carnie and Noric); Mount Heslington (Car-

MUEUSTEa. ci oe nic); Eighty-Eight Valley (Kaihiku or Ladino-Carnic
and Carnic).
Okuku. Carnic, Noric(?).
Mount Potts. Kaihiku or Ladino-Carnic, and Lower Carnic.
Mount St. Mary. Kaihiku or Ladino-Carnic, and possibly Lower Carnic.
Hokonui Hills : Gore (Carnic, Noric) ; Otamita (Carnic, Noric) ; East
North side. Peak (Kaihiku or Ladino-Carnic).

: Caroline railway-cutting (Kaihiku or Ladino-Carnic) ;
= SELES Slee Benmore Cutting (Rheetic).
Kaihiku Gorge. Kaihiku or Ladino-Carnic, Carnic, Noric.
Nugget Point. Kaihiku or Ladino-Carnic, Carnic, Rhetic.
Moonlight Range. Carnic, Noric.

The localities in the South Island are probably connected along
the structural axis by others where the fossils are still undiscovered,
or have been more or less obliterated through metamorphism.

North Island.

Kawhia.

The Jurassic strata are well exposed round the shores of Kawhia
Harbour, where they le unconformably beneath a horizontal cover
of Tertiary limestones, and Kawhia is the most important locality
in the North Island for Jurassic fossils. Outside the harbour in

the Nelson district. At Mount Potts and Mount St. Mary the Triassic beds
form part of the eastern fringe of the complex of the Alpine Range, and are
crushed and partly metamorphosed. Except immediately south-west of
Kawhia Harbour, and on the southern and western side of the Hokonui
Hills, the Triassic beds stand everywhere practically vertical.

At Kawhia, and in the far south, the Trias is succeeded conformably by
Jurassic rocks. At Nelson and in the Alpine Region no Jurassic is known.
In the Nelson district fossiliferous Trias, from the Ladino-Carnic to the Noric
inclusive, occurs. The Triassic limestones at Okuku are of uncertain
age, but probably Carnic. At Mount Potts and Mount St. Mary the
Ladino-Carnic (Kaihiku) and possibly Lower Carnic occur. In the ranges
extending from the Hokonui Hills to Nugget Point all divisions, from the
Kaihiku to the Rheetic inclusive, are fossiliferous, and the overlying Jurassic
is also highly fossiliferous.

174 DR. C. T. TRECHMANN ON [vol. lxxiii,.

the coast-section extending southwards and south-westwards the
Jurassic deposits pass conformably down into a thick series of grey
felspathic sandstones with bands of pebbles and conglomerate-beds.
These beds gradually become increasingly inclined until Tarawai
Point, north of Albatross Point, is reached. Fossils are scarce, but
quite high up in these beds Prof. Marshall and I found a specimen
of Arcestes cf. rheticus, and a little lower down another sunilar
but indeterminable dvcestes. Brachiopods occur sparingly, gener-
ally in little clusters throughout a great thickness of these rocks.
The commonest form is Hectoria bisulcata, and rather high up
(but below the Arcestes) I found two specimens of MMentzelia.
These beds are presumably Rheetic.

At Tarawai Point, some miles south of Kawhia Harbour, there
is a large intrusion of a hypabyssal porphyry of the syenite group,
and the sedimentary rocks are here nearly or quite vertical. A
black argillite full of Pseuwdomonotis ochotica and its varieties
occurs in very close association with this intrusion, and seems in
places to’ underlie and become involved in it. Great masses of
this dark shale are found mixed up with blocks of porphyry lying
on the shore. These beds are Noric, and are the lowest Trias.
that I saw in this locality. McKay,! in a sketch-map appended
to his report of the district, shows a repetition of the Wairoa,
Otapiri, and Bastion Series south of the igneous intrusion, but says.
that the rocks were not examined. Prof. Marshall, who on a pre-
vious occasion visited that very rugged portion of the coast in a
boat, tells me that he saw no fossils - Ehere

South Island.
Nelson Area.

The strip of fossiliferous Trias in this district extends in a north-
easterly and south-westerly direction from near Richmond to
Eighty -Hight Valley, a distance of about 12 miles. Its greatest
width is about three- quarters of a mile, near the Wairoa Gorge.
The beds are steeply inclined. Various sections have been drawn
to show the arrangement of the beds, but the structure is com-
plicated and involved. Great diver gence of opinion exists regarding
the presence or absence of faults, and the relation of the Trias of
the foothills to the Maitai Limestones and Argillites which form
the higher peaks that bound it on the south-east. In the Wairoa
Gorge the Maitai Limestone contains an Upper Paleozoic fauna,
and closely adjoins the dark greywackes full of Mytilus prob-
lematicus. At Richmond the felspathic sandstones containing
Pseudomonotis richmondiana are sharply cut off on the east by
unfossiliferous red and green slaty argillites of the Maitai Series.

The Kaihiku Beds appear only in Eighty-Eight Valley at the
south-western end of the Triassic outerop. “Here they are wedged
in between Maitai Limestone on the south-east and the Upper

| Bibliography, 30.

part 3] THE TRIAS OF NEW ZEALAND. 175

Trias on the north-west. The strip of Kaihiku Beds is half a mile
long and a quarter of a mile wide, and the strata dip south-south-
eastwards at 55° to 65°.

In the Wairoa Gorge the Mytzlus-problematicus Bed occurs
near the entrance, and again on the east close to the Maitai Lime-
stone. The intervening space is occupied by the higher beds of
the Carnie. .

In the hills south of the gorge the Psewdomonotis-richmondiana
Beds oceur in full thickness, but are not seen in the gorge itself.
At Garden Gully, about a mile south-west of the Wairoa Gorge, I
found a bed of fine-grained greywacke containing many varieties
of the Asiatic Noric fossil Psewdomonotis ochotica. It seems to
oceupy the limb of a syncline, possibly a faulted syncline, and
I believe the Noric Psewdomonotis-ochotica Beds to be the highest
that occur in the Nelson area.

No Jurassic fossils have been found in this part of the South
Island. Allthe evidence that I saw led me to conclude, in opposition
to recent Survey results,! that there is a series of strike-faults
parallel to the structural axis and that the Trias is partly overthrust
to the north-west by the Maitai Series. The Tertiary deposits of
the Waimea Plains, which bound the Trias on the north-west,
are tilted up along their junction, and are probably overthrust to
some extent in their turn by the Trias.

Okuku (Ashley County).

The geology of this very mountainous district is little known.
McKay studied and described it in 1879,? and states that the
whole of the northern end of the Mount-Torlesse range is occupied
by Trias and younger formations, which form the higher peaks of
Mount Torlesse. he rocks consist of a great thickness of con-
glomerates, sandstones, red and green so-called ‘diabasie ash’ (by
which one may probably understand coarse greywacke), and lime-
stones. Mytilus problematicus and Monotis salinaria are said to
occur in the limestones and in the ‘diabasic ash.’ These fossils
are found in immense numbers in the Upper Okuku Valley, ina
limestone associated with cherts. I had no opportunity of visiting
this locality, and McKay’s report is not quite clear as to whether
the Monotis and Alytilus occur together or in separate strata. I
examined a series of the Monof/s-like shells in the limestone from
this district belonging to the New Zealand Geological Survey, and
selected several examples to be sent to England. ‘These pieces of
limestone contain AZonotis, but no Mytilus. I could find no trace
of the anterior byssal notch characteristic of Psewdomonotis in
any of these shells, and therefore am compelled to regard them
as really the Alpine JZonotis salinaria. If this be the case, their
reported association with Mytilus problematicus may be explicable,
as Monotis salinaria is recorded from Carnic horizons in Europe.
Perhaps future research in the district may clear up these points.

1 Bibliography, 22, pp. 20-22. * Bibliography, 29.

176 DR. C. T. TRECHMANN ON [vol. lxxiul,

Mount Potts.

The chief interest of this locality centres in the plant-beds
discovered by McKay in 1877. Great uncertainty has arisen over
the age of these beds and the associated marine fossils, owing
to Hector’s determination of Glossopteris among the flora. The
district, which is extremely mountainous, was described by MeKay,!
who states that the plant-beds of Tank Gully underlie the marine
‘Spirifer’ Beds. Later, however, he says that plant-remains
overhe the Kaihiku in the district between the Rangitata and
Ashburton Rivers.” The fossils in the marine beds have been
variously determined as Permian, Lower Carboniferous, or Upper
Devonian; but my examination of the Geological Survey Collection
and of a series collected by Prof. Marshall convinced me that they
‘are all Triassic. They occur in black, compressed and fractured,
slaty argillites. The following forms are present:—

A Nautilid. Spiriferina (Cyrtina 2) caroline,
Small gasteropods with angular sp. nov.
whorls. | Spiriferina sp.
Daonella indica Bittner. Halorella sp.
Pinna sp. | Dielasma sp.
Anodontophora sp. | Mentzeliopsis sp.
Spirigera kathikuana, sp. nov. | Crinoid-stems,

Mr. McKay told me that Mytilus problematicus occurs there,
but there is no trace of AZonotis or Pseudomonotis.

The great majority of the fossils are those of the Kaihiku and
are of early Upper or late Middle Trias. The only forms that
indicate a Carnic horizon are Nautilus and Pinna. Reptilian
remains occur in some of the beds, the large narrow amphiccelous
vertebra of which suggest some form of [chthyosaurus.

The late Dr. E. A. N. Arber® examined a series of the plants
which Mr. D. G. Lille collected here in 1911, with the result that
the supposed Glossopteris turned out to be a new form, to which
he gave the generic name Linguzfoliwm, and the whole flora proved
to be either late Triassic, Rhetic, or early Jurassic. Dr. Arber,
however, informed me that, at present, it 1s impossible to distinguish
between late Triassic and early Jurassic floras. From the evidence,
both of the flora and of the associated marine fauna, it seems per-
fectly justifiable to attribute an Upper Triassic age to the plant-
beds of Mount Potts; but the question as to the position of the
plant-beds relatively to the marine horizon is one on which further
evidence is needed.

Mount St. Mary.

The fossiliferous outcrop at Mount St. Mary occurs at an
altitude of 5160 feet. Fossils occur in three zones in a thickness
of 50 feet: the two lower zones are slaty shales and the upper a

1 Bibliography, 28, p. 92. 2 Bibliography, 28, p. 95.
3 Bibliography, 2.

part 3] THE TRIAS OF NEW ZEALAND. Lee
conglomerate. The fossiliferous rocks are associated with altered
sandstones, and follow the phyllites, quartzites, ete. (known as the
Kurow Schists) in direct stratigraphical succession. At the foot of
the mountain the dip is very high, and at the fossiliferous out-
crop it is about 60°. Prof. Park! says that the thickness of the
strata exposed in the section is not less than 10,000 feet, and he
gives a careful enumeration of these metamorphic and semi-meta-
morphic rocks. His attribution, however, of a Permo-Carboniferous
age to the fossils is erroneous, as they are all Triassic, and the
majority belong (as do those at Mount Potts) to the Kaihiku
Series. I examined the series in the Geological Survey Collec-
tion, and also a collection which Prof. Marshall made. Many of
the forms attain an unusually large size, but are much crushed
and distorted: they occur in a fissile slaty argillite or greywacke.
I identified the following forms :—

A crushed Nautilid.

Patella (2), crushed.

Pleurotomaria sp. and another small
gasteropod.

Tima sp.

Part of a large indeterminate bi-
valve.

Spirigera resembling Sp. kaihiku-
and, Sp. Nov.

Mentzeliopsis sp. of unusually large:
size.

Large alate Spiriferine and a small
form resembling Spiriferina fra-
gilis Schlotheim.

Many small specimens of Megalodon Large Dielasma.
ef. globularis, sp. nov. in a coarse,

gritty felspathic sandstone.

There is no trace in this fauna of Hectoria, Halobia, Mytilus,
or Pseudomonotis.

It is quite certain that the slaty shales contain the Kaibiku
fauna, and are of late Middle or early Upper Triassic age, while the
Megalodon-like bivalves in the higher conglomerate-bed suggest.
the presence of part of the Carnie horizon below the Mytilus-
problematicus Bed.

Hokonui Hills.

The Hokonui Ranges consist of a series of conformable Triassic
and Jurassic rocks. On the north-east they are bounded by the
Waimea Plains and the Waimea River, a tributary of the Mataura,
and on the south-west and south-east by the Makerewa Flats and
the Oreti River. Their structure was investigated by 8S. H. Cox?
and A. McKay? in 1878. The hills rise to a height of about
2500 feet, and are part of a range extending from the Takitimu
Mountains to Nugget Point on the south-eastern coast of Otago.
The Government surveyors estimated the thickness of the strata
at 21,000 feet or more. The structure is roughly that of a trough,
of which only the northern and western edges are exposed. The
axis follows roughly a south-easterly trend at its western end and
a nearly easterly trend at the eastern end. The beds along the
northern and north-eastern fringe of the hills stand nearly vertical,

while on the southern and western side the dip rapidly decreases.
3 Bibliography, 27.

1 Bibliography, 38. 2 Bibliography, 9.

178 DR. C. T. TRECHMANN ON [ vol. lxxin,

till they form a flat syncline with an axis oriented north-west and
south-east. The result is that the outcrop of the beds bends
round, and becomes much wider on the south-western side. In
consequence, the Triassic rocks occupy the northern and western
fringes of the hills; while the inner and less accessible part of the
range, together with the southern and south-western portion, is
occupied by the much less strongly inclined Jurassic deposits.

The great mass of greywackes and conglomerates, called the
Kaihiku Series, estimated as 6600 feet thick, occupies the northern
fringe. The thin fossiliferous band, which occurs 4000 feet
above the lowest beds seen in the district, crops out at various
points as a continuous bed. It is seen in a railway-cutting a mile
south of Caroline Station, and at East Peak, whence it extends
eastwards in the direction of the Kaihiku Gorge, from which it
takes its name, and finally reaches the coast at Nugget Point.

I visited various localities in the Hokonuis in company with
Prof. Marshall, but most of our collecting was done at a spot,
previously known to Prof. Marshall, in the valley of the Otamita
Stream some distance west of East Peak. This stream, according
to the map published by Cox & McKay, flows eastwards in the first
part of its course approximately down the junction of the Otapii
and Upper Wairoa Series. It then turns northwards and cuts across
the strike of the Lower Wairoa and Kaihiku Series, ultimately
joining the Mataura. The section that we observed on both banks
of the Otamita Stream is as follows :—

| Approximate | )
Beds. | thickness in Fossils. Age. |
feet. tF

a. Massive felspathic grits 20 Fragment of Pinacoce- P
and sandstones. ras, alate Spiriferine. Noric.

b. Felspathic sandstones! Nautili, Arcestes, Dis-| \ |
interbedded with shaly 20 cophyllites, Halobia
bands. hochstetteri, ete.

c. A massive bed of dark, Halobia _ hochstetterr |
hard, but fissile crumb- and many other well-| | |
ling shale, with concre- 25 preserved fossils,) |
tionary nodules in its Nautili, Discophyl-
lower part. lites.

d.-Felspathic sandstones) Pleurophorus, Spiri- |
and argillites. P ferina, etc., badly) } CARNIC.|

| preserved. | |
le. Dark-grey rusty shales| Halobia zitteli var. |
with small rounded py-. zealandica, Spirigera, |
rite nodules, and bands 100 manzavinioides, Spi-
of felspathic sandstone riferine, Conularia,
weathering in spheroidal) and many other fos-| |
masses. sils. | | |
\f. Dark slaty shales. | P ‘Full of Mytilus pro- |

blematicus. )

part 3] THE TRIAS OF NEW ZEALAND. 179

Fossils are unusually well preserved in beds ¢ and e. The
Geological Survey reports make no mention of the occurrence of |
Mytilus problematicus in the Hokonui Hills, and so it would
appear that this section was overlooked by the Government surveyors
in 1878.

Kaihiku Gorge.

This gorge cuts across the strike of the Triassic range between
the Hokonui Hills and Nugget Point. At the entrance of the
gorge several blocks fallen from the rock that crops out on the
grassy hillside, but is not well exposed, contain the fauna which
takes its name from the locality. The fauna, a very constant one,
corresponds exactly to that found at various points in the Hoko-
nuis and at Eighty-Hight Valley, near Nelson. Some distance
above this a thick coarse conglomerate occurs, overlain by a hard
greywacke full of indeterminable plant-remains. A thick series
of spheroidal felspathic sandstones represent the Wairoa and
Otapiri Beds, but fossils are very scanty. In the stream I found
a piece of a Pinacoceras, evidently washed down from the higher
Triassic beds.

Nugget Point.

This is one of the clearest sections of the Trias in New Zealand.
In Roaring Bay or Shaw Bay, south of Nugget Point Lighthouse,
the beds are ranged almost vertically for a distance of nearly a
mile. It is possible to obtain a good idea of the thickness and
succession of the fossiliferous Trias. Here, however, although
the Carnic with the Mytilus-problematicus Bed is well ‘developed,
the Pseudomonotis Beds of the Noric are missing. The series
commences with hard unfossiliferous greywackes and felspathic
sandstones, upon which the hghthouse stands. Slhghtly south of
this, Prof. Park tells me that fossiliferous bands in the Kaihiku
Series occur, although I did not succeed in finding them. The
Carnic Series is excellently developed, and yields many fossils,
showing several recognizable zones. About 195 feet above the
Mytilus-problematicus Bed is a band of ferruginous sandstone with
fragmentary plant-remains, where I collected a fragment of a frond
which I identified as Thinnfeldia ct. odontopteroides Morris.}
The late Dr. E. A. N. Arber kindly confirmed this identification,
and informed me that this species is commonest in the. Upper
Trias, although not confined to that horizon. The Noric is not
recognizable here; but Prof. Marshall has recently traced it at
Glenomaru, about 10 miles inland from Nugget Point. A frag-
ment of the rock that he sent me is full apparently of the small
rounded and arched variety of Psewdomonotis richmondiana. The
Triassic System comes to an end, about a mile south of the light-
house, with a hard, resistant, pebbly and glauconitie or chloritic
felspathic conglomerate, full of Heetoria (Clavigera) bisulcata

1 Now in the Sedgwick Museum, Cambridge.

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part 3] THE TRIAS OF NEW ZEALAND. 181

and the very alate Spiriferina diomedea. The section was de-
scribed by McKay, and later by Park. I confirmed the htho-
logical sequence as Prof. Park! represents it, and have added in
fig. 2 (p. 180) my interpretation of the zones represented after
examining the fossils collected there.

Moorlight Range.

This- les more or less on the westward continuation of the
Hokonui Hills, but the geology of the district is very little known.
A considerable series of Triassic rocks is probably present there.
In the Geological Survey Collection from this locality I identified the
following forms: Pseudomonotis richmondiana Zittel, and a large
flat form like Ps. ochotica Teller, var. densistriata, Halorella sp.,
and a small bivalve.

V. PALZONTOLOGY.

CEPHALOPODA.

The Cephalopods of the New Zealand Trias belong to the genera
Orthoceras, Clydonautilus, and Grypoceras among the Nautilids ;
A ulacoceras, among the Belemnoids ; and among the Ammonites,
Arcestes, Cladiscites, Pinacoceras, and Discophyllites. The last
is the only ammonite sufficiently well preserved to afford any
real zonal information. No cephalopods have been found in the
Kaihiku Beds, and the Trias of New Zealand shares with that
of New Caledonia and the Malay Archipelago the absence of
ammonites of the Ceratitic type, or of the profuse Upper Triassic
ammonite fauna which occurs in Western America and in the
Himalayas.

OrTHOCERAS sp. (PI. XVII, fig. 6.)

Surface of the shell smooth; growth-lines straight, not sinuous.
The septa are rather strongly convex towards the apex, and the
siphuncle is slightly excentric. Length originally =about 40 mm.;
diameter of aperture—6 mm.; and length of living chamber=about
11mm. The aperture of the latter is preserved, and is circular in
outline, quite horizontal; the rim is slightly thickened. In the
angle of emergence and other features it resembles O. trtadicui
Mojsisovics.

Locality and horizon.—The only locality that I know where
this dwarfed Orthoceras occurs is Bed c, Otamita, Hokonui Hills,
.Garnic. Previous records of Orthoceras seem to have been based
on parts of the phragmocones of large Atractitid belemnites.

4ZRYPOCERAS cf. MESODIScUM Hauer.
1902 E. ron Mojsisovies, ‘ Cephalopoden der Hallstitter Kalke’ vol.i, Supplem.
1910. @ Buln, Centralblatt f. Min. &¢. p. 635.
The name of Nautilus mesodiscus appears in Hector’s list of
1 Bibliography, 39, p. 382 & pl. xxix.
OG. 5. No. 291. Q

182 DR. C. T. TRECHMANN ON [vol. Ixxii,

fossils of the Otapiri Series, and this attribution is confirmed by
Diener on the strength of a specimen which Prof. Marshall sent:
to Boehm. Several specimens of this shell that I collected confirm
Diener’s observations on the external ornamentation, which consists.
of longitudinal lines crossed by fine transverse lines. The sutures
show a very shallow ventral lobe and sunilar, but rather deeper,
lateral lobes, and a small, well-marked, annular lobe. ‘The siphuncle
in a specimen of three whorls occurs about midway between the
centre and the ventral margin.

Locality and horizon.—Bed c, Otomita, Hokonui Hills;
Nugget Point, and other localities. Carnie.

CLYDONAUTILUS (PROCLYDONAUTILUS) cf. sprroLOoBUS Dittmar.
GRE XaVaT ste 3..)

1902. E. von Mojsisovics, ‘Cephalopoden der Hallstatter Kalke’ vol. i, Supplem.

pet & plix, fic. 3, ple xl es Ie

1910. G. Boehm, Centralblatt f. Min. &c. p. 634.

A Nautilid with angular sutures was sent by Prof. Marshall to
Boehm, and handed on to Diener, who identified it as near the
above species. In specimens that I collected the lobes are angular
and the saddles rounded, strongly recalling those of a nearly-allied
species Pr. goniatites Hauer. The siphuncle of a specimen of
three whorls is dorsad of the centre. The surface of the shell
slopes more towards the venter, and is less rounded than in either
Pr. sptrolobus or Pr. goniatites ; while the venter itself is narrow
and gently rounded.

Locality and horizon.—It is common in Bed c¢, Otamita
(Hokonui Hills), and occurs also at Nugget Point and other
localities.

ARCESTES sp.

1909. Arcestes hokonui P. Marshall, Trans. N.Z. Inst. vol. xli, p. 144,
1910. G. Behm, Centralblatt f Min. &¢. p. 634.

Arcestids are fairly common in the Carnic beds, especially im
Bed ¢ at Otamita. Prof. Marshall sent a specimen from this.
locality to Beehm, who submitted it to Diener. As the living
chamber was missing, he could not say whether it was Arcestes or
Proarcestes, and considered it better not to give any specific name.
No specimen that I saw or found had the living chamber, and so I
cannot add anything to Diener’s observations. If more complete
specimens could be obtained, it would probably be found that several
species of Aicestes are present i in the New Zealand Trias.

Axrcxstes cf. romricus W. B. Clark. (PI. XVIL, fig. 1.)

1888. Am. Journ. Sci. ser. 3, vol. xxxv, p. 119.
1895. J. Kh. Pompeckj, ‘ Ammoniten des Rhat’ Neues Jahrb. vol. 11, pt. 1, p. 3.

Shell smooth, sides and venter rounded, umbilicus wide and.
deep; the umbilical shoulders are rounded, and slope towards the

part 3] THE TRIAS OF NEW ZEALAND. 183:

umbilicus. The living chamber is wanting; but on the last whorl
two slightly-sinuous channels cross the venter and sides nearly
opposite one another, and represent former contractions of the
aperture.

This specimen agrees in outer shape with Arcestes rheticus,
a form for which Hyatt has proposed the new generic name
Rhetites, but seems to differ in the sutures. Five saddles are seen
between the siphuncular saddle and the umbilical shoulders, the
fourth being higher up though not larger than the rest. ‘The saddles
are deeply cut on each side into four auxiliary saddles, and the
siphonal lobe is divided by a saddle into two points which are not
deeper than the lateral lobes. In Avcestes rheticus the sutures.
are said to form a series of lobes and saddles which gradually
decrease in size from the siphuncle, and the two siphuncular lobes
are deeper than the lateral lobes.

Mojsisovics says that Pompeck]j considered <Arcestes rheticus
to be merely part of the inner whorl of an Avcestes of the Galeati
group.

Locality and horizon.—The specimen illustrated in Pl. XVII
was collected by Prof. Marshall and myself high up in the Rhetic
between Kawhia Harbour and Albatross Point, 8000 feet or more
above the Noric Psewdomonotis Beds. It is probably the highest
Triassic fossil that we obtained in New Zealand: it is entirely
distinct from the Arcestids in the Carnic, which are much smaller,
more involute, and lack the deep funnel-shaped umbilicus.

Crapiscires sp. (PI. XVII, fig. 2.)

Sides flat, sloping gently towards the small shallow umbilicus ;
venter gently rounded. The living chamber is missing and the
shell destroyed, and consequently it is impossible to see whether
there was any surface decoration. No specific name can, therefore,
be given.

Locality and horizon.—The only specimen of this genus
known to me comes from the Nautilus Bed at Mount Heslington,
Nelson. Carnic.

PINACOCERAS sp.

All the specimens of Pinacoceras that I saw are fragments of
air-chambers, and no satisfactorily-preserved example has come to
light. One cannot, therefore, say more than that this genus, or
some similar large and flat phylogerontic form with very compli-
cated sutures, occurs in the higher Triassic deposits.

Locality and horizon.—I found a fragment in a bed at
Otamita, in the Hokonui Hills, which is probably Lower Noric ;
and in the Geological Survey Collection is a piece of a very large
flat Penacoceras, but with greatly eroded sutures, from beds on
the eastern side of Mount Heslington, near Nelson, which may also
be Lower Noric.

Q 2

184 DR. C. T. TRECHMANN ON [vol. xxii,

DIscoPHYLUITES cf. EBNERI Mojsisovics. (Pl. XVII, fig. 7.)

1896. Phylloceras (Mojsvarites) ebneri ‘ Obertriadische Cephalopodenfauna des
Himalaya’ Denkschr. k. Akad. Wissensch. Wien, vol. lxiii, p. 668 (96) &
pl. xix, fig. 6.

1506. C. Diener, ‘Fauna of the Tropites Limestone of Byans’ Pal. Ind. ser. 15,
vol. v, Mem. 1, p. 173 & pl. v, fig. 5.

Shell smooth or exhibiting faint growth-lines; whorls gently
rounded, increasing rather rapidly; the umbilicus wide and open,
each whorl embracing about half the previous one. Umbilical
shoulders in the more adult shell are rounded and rather over-
hanging. The earlier whorls are much flatter than the later, which
in very large specimens become much rounded.

Locality and horizon.—Bed c¢, Otamita (Hokonui Hills).
The fragment illustrated occurred near the MWytilus-problematicus
Bed, south of the Wairoa Gorge, Nelson. In the Geological
Survey Collection is a magnificent specimen from Nugget Point,
measuring 18 inches in diameter. Carnic. Large Discophyllites
are recorded from New Caledonia.

Remarks.— Discophyllites is a sub-generic name proposed
by Hyatt for a group of forms connecting Monophyllites and
Rhacophyllites. The peculiarities of the suture are said to be
that the siphonal lobe is deep and narrow, and divided by a high
median prominence, and the siphonal saddle is diphyllic. Three
species have been described: D. patens Mojsisovies, from Europe ;
D. ebneri Mojsisovics, from the Himalayas; and D. insignis Gem-
mellaro, from Sicily. Prof. Diener remarks that all three form a
well-defined and closely-allied group ranging from Middle Carnic
into Lower Noric strata. 'The New Zealand form seems to agree
closely with the Himalayan D. ebnerz.

AvLacocErRas sp. (Pl. XVII, figs. 4 & 5.)
1878. Belemnites otapiriensis Hector, Trans. N.Z. Inst. vol. x, p. 488.

In one example the end of the guard and the anterior part of the
phragmocone are both missing. The guard is soft and friable, and
there are one or more longitudinal grooves on it. The phragmocone
is nearly twice as long as the guard, and has eleven or twelve air-
chambers remaining. The septa are irregularly spaced, and the
siphuncle is marginal. A label attached to this specimen (which is
figured in Pl. XVII, fig. 4.) states that it is the holotype of Hector’s
Belemnites otapiriensis. A highly-idealized illustration of this
specimen, which Hector caused to be printed, has recently been
issued.! It is 150 mm. long.

Another specimen consists of a fragment of a guard in very hard
greywacke, which, when dissolved out with acid, yielded a gutta-
percha squeeze (illustrated in Pl. XVII, fig. 5). About half the
surface is seen, and has three longitudinal ribs separated by two,
sharp and deep furrows. The surface of the ribs is gently rounded,

1 Bibliography, 47, pl. v, fig. 1.

part 3] THE TRIAS OF NEW ZEALAND. 185

and one of them bears five longitudinal parallel cuts. A very sharp
and faint rib passes down the bottom of each of the furrows.

Locality and horizon.—Hector’s specimen comes from Oreti
railway-cutting (Hokonui Hills), and is probably Noric; the frag-
ment of guard is from the Spiriferina Beds at Eighty-Hight Valley,
Nelson, and is probably Carnic. Both specimens belong to the
New Zealand Geological Survey Collection.

Remarks.—The first specimen is contained in a large piece
of decomposed felspathic sandstone, and seems to be specifically
indeterminable. The fragment of guard agrees well with a
similar fragment of Awlacoceras sulcatum Hauer, illustrated by
Mojsisovics.!

The New Zealand Geological Survey possesses fragments of
phragmocones of belemnites of the Afractites group which are of
large size; but most of them seem to be from Jurassic deposits.

GASTEROPODA.

PATELLA (?) NELSONENSIS, sp. nov. (Pl. XVIII, figs. 8a & 86.)

Shell patelliform, the apex directed forwards and situated about
the anterior third portion of the shell. The shape is not always
symmetrical: in one example the apex is slightly inclined to the left,
and in another the left anterior position of the shell slopes more
steeply than the rest of the surface. The decoration consists of
fine rounded ribs, which radiate from just below the apex to the
margin. Between the primary ribs three or four smaller ones com-
mence at various distances below the apex, but do not attain the
strength of the primary ribs. The ribs are crossed by a regular
series of faint, close-set, concentric growth-lines, giving the surface
a latticed appearance. The shell is fairly thick, and the muscle-
scar in the interior is broad, but not very distinct, and in one
specimen seems to continue round the inside of the shell, while
in another it appears to be interrupted on the left anterior side.
The largest specimen that I examined was 71 mm. long, 65 mm.
wide, and 386 mm. high.

Locality and horizon.—lIt has only been found in the Kaihiku
Beds at Eighty-Eight Valley (Nelson district). Ladino-Carnic.

The New Zealand Geological Survey possesses several large
examples, of which, except in one instance, the interior casts
alone have been preserved. From this one I made a gutta-percha
impression showing the outer surface, which I have taken as the
holotype. It hasa small mass (apparently of stromatoporoid coral)
attached to its outer side.

Remarks.—It is possible that this shell may be a Capulid or
perhaps a Stphonaria, in which case the apex would be posteriorly
directed. The apparent interruption of the muscle-scar on one
side rather suggests the latter genus as being the correct one.

1 Bibliography, 32, pl. xiii, fig. 4.

186 DR. C. T. TRECHMANN ON [vol. lxxin,

PLEUROTOMARIA (SISENNA) HECTORI, sp. nov. (Pl. XVIII,
figs. 5 a—5 ¢.)

Shell consisting of about seven whorls; the spire is depressed ;
the upper surface of the first three whorls is nearly flat, but in the
later whorls it is rather concave and slopes towards the line of nodes.
The slit-band occurs about two-thirds of the distance above the base
of the body-whorl and nearly half the distance above the suture of
the penultimate whorl. The earliest whorls seem to be smooth.
A row of heavy rounded nodes occurs both above and below the
slit-band; those below it project beyond the sht-band, and form the
keel of the shell. The nodes above and below the slit-band are of
about equal size, are rather irregularly spaced, and occasionally tend
to coalesce one with the other. The slit-band has a faint furrow
above and below it, and between it and the nodes. Below the keel
the surface of the shell is sightly concave ; 1t then becomes convex,
and then again concave towards the umbilicus, which is partly
covered and obscured by a thin callosity of the inner lip. Below
the keel the growth-lines bend sharply backwards, and then curve
forwards again and pass to the umbilicus. This forward curving
produces a tongue-like projection of the lip below the notch. The
notch of the lip is about 1Omm. deep, the diameter of the shell is
34 mu., its height 20 mm., and the height of the spire 15 mm.

Locality and horizon.—Bed c, Otamita (Hokonui Hills).
Carnic. I collected two or three very fine specimens here. I also
found casts of it in the Carnic beds in the river-section of the
Wairoa Gorge, and a cast of this (or of a very similar shell) in
the Noric beds, with Pseuwdomonotis ochotica, at Garden Gully ,1n
the Nelson district.

Remarks.—This shell may be placed in Koken’s Pleurotomarid
group Sisenna, which includes several Upper Triassic forms having
a depressed spire, step-like whorls, and the slit-band situated be-
tween two ridges on the upper and outer side of the whorl. The
tongue-like projection of the lp below the notch is also charac-
teristic of this group. Koken says, however, that in S/senna the
umbilicus is open, whereas in the form here described it is partly or
completely covered. It bears a rather remote resembiance to a shell
from the Upper Trias of Bear Island in the Arctic Ocean, called
by J. Boehm Stsenna conwentzi,’ in which the umbilicus is also, as
in the present shell, covered by a thin labial callosity.

PLEUROTOMARIA HOKONUIENSIS, sp. nov. (PL XVIII, figs.
6 a-6 ¢.)

Shell small, consisting of seven whorls increasing rather rapidly.
The apex is pointed, and the earliest whorls are angular. About the
fourth whorl a row of vertically-elongate nedes appears below the
suture, together with five or six spiral thread-like lines, one of
which crosses the centre of the line of nodes. The ornamentation

1 Bibliography, 8, p. 51 & pl. vi, figs. 1, 9, 10, 16

part 3] _ WHE TRIAS OF NEW ZEALAND. 187

almost disappears on the last whorl of some specimens, which in
consequence become nearly smooth above the slit-band. ‘The latter
is rather broad, and occurs above the keel in the last whorl. The
keel is decorated with a line of blunt nodes, and there are a number
of parallel threads between it and the slit-band. Beneath the
keel are about eight concentric spiral lines, which are crossed by
the growth-lines. The umbilicus is covered by a callosity of the
inner lip. The slit-band seems to cone saa ag to a rather deep
notch in the lip. Diameter=18 mm.; height=10mm.

Locality and horizon.—Bed ¢, Otamita (Hokonui Hills),
where it is common. Also on Mount Heslington, Nelson. Carnie.

‘TrocHus (TECTUS) MARSHALLI, sp. nov. (Pl. XVIII, fig. 7.)

Shell trochiform, consisting of eight whorls, which are sharply
keeled, and each one slightly overhangs the suture below it. The
whorls are slightly concave above the keel. Below the keel the
base is hollowed out and concave. The keel is decorated with a
line of forward-pointing nodes, which rather resemble the teeth of
asaw. ‘he lower part of each whorl above the keel is decorated
with five or six parallel thread-lines, and beneath it are several still
fainter lines.

The columella is strong and twisted, and folded near the inner
lip. The aperture was not preserved. Diameter=15 mm.; height
tO Min.

Locality and horizon.—Bed ec, Otamita (Hokonui Hills),
where Prof. Marshall collected it during one of our visits. Carnie.

Remarks.—Several species of Trochoid shells with a twisted
inner lip occur in the Alpine Hallstatt Limestone, and are figured
by Koken under the generic name Yecfus; but none of them
resemble the form here described. {[t may seriously be questioned
whether these Mesozoic Trochoids are congeneric with the Tertiary
and recent genus Jectus.

CORONARIA SPECTABILIS, sp. nov. (Pl. XVIII, fig. 4.)

The shell consists of fifteen or more whorls which increase slowly
in size; the test is fairly thick, the nodes being but faintly visible
on the ‘internal cast. The decoration consists of a series of pro-
minent rounded nodes of elongate outline, arranged with their
jonger axes upright. The nodes occupy most of the surface of each
whorl, but above them, and just below the suture, is a flat band
which bears three or four raised spiral lines with shallow grooves
between them. A series of fainter raised spiral lines passes round
that part of the whorl which is oceupied by the nodes, and across
the depressions between them. The umbilicus seems to have been
shallow; but the shape of the aperture or lip could not be
ascertained. The earliest whorls appear to have been devoid of
ornamentation. The holotype is 96 mm. long, and has an apical
angle of 14°.

Locality and horizon.—Western slopes of Mount Heslington,

188 DR. C. T. TRECHMANN ON [vol. ]xxin,

south of the Wairoa Gorge (Nelson), where fragments, often of

large specimens, are not rare. It is also found at Nugget. Point.
Carnie.

The holotype is a mould belonging to the Geological Survey
Collection, and comes from Mount Heslington. After preparing it,
I was able to make a gutta-percha squeeze (fig. 4). The Survey
also possesses a poorly-preserved fragment, consisting of several
whorls, of a specimen from Nugget Point, which must have
measured nearly a foot in length. I have several fragments from
Mount Heshngton.

Remarks.—This handsome shell seems to agree generically with
Koken’s genus Coronaria, of which several species occur in the
Hallstatt Limestone. The genus resembles in some ways the
Zygopleura group of the Loxonematide.

BovuRGUETIA (7) ARATA, sp. nov. (Pl. XVIII, fig. 3.)

This shell consists of six or seven whorls, which increase rather

rapidly in size; the body-whorl is large and rounded, and occupies.
rather more than half the length of the shell. The sutures are
rather deep, and the whorls form a narrow platform below them.
The decoration consists of spiral, rounded, parallel, raised, equidistant:
ridges, between which are furrows of about the same width as the
ridges. There are about fifteen ridges on the body-whorl. A
shallow umbilicus seems to be present, but the shape of the aperture
could not be seen. Height=321nm.; width of body-whorl=24 mim.

Locality and horizon.—Mount Heslington (Nelson). ‘The
holotype from which I made a outta- -percha impression belongs,
together with several fragments from the same locality, to the
Geological Survey Collection. . I found a cast of a smaller spe-
cimen, 20mm. high, in hard greywacke at Nugget Point. Carnic.

Remarks.—Owing to the poor state of preservation of the
material, the generic position of this shell cannot be determined
with certainty, and its attribution to Bourguetia is somewhat
conjectural.

Dentatium sp. (PI. XVIII, fie. 2.)

Length=originally about 87 mm. Greatest breadth=7 mm. at
the anterior end; the posterior end is missing. ‘The shellis gently
curved: it is oval in section at the anterior, and nearly circular
towards the posterior, end. The shell is rather thick, smooth, and
ivory-like, with fine concentric growth-lines. The edge of the
aperture is sharp and oblique, the margin being high and convex on
the coneave side, and concave on the ventral or convex side of the
shell. ‘The surface towards the aperture is rounded on the concave,
flatter on the convex side. The growth-lines correspond to the
obliquity of the aperture.

Locality and horizon.—Bed ¢, Otamita (Hokonui Hills).
Carnic.

part 3 | THE TRIAS OF NEW ZEALAND. 189

Convnaria sp. (PI. XVIII, fig. 1.)

Length=originally about 27 mm.; width at the aperture=9 mm.
The section seems to be more or less square or rectangular. In
most of its features this Conularia resembles C. /evigata Morris.
from the Permo-Carboniferous of Australia, which also occurs in
beds of similar age in the Salt Range. In the fineness of its strie
it recalls also C. tenuistriata McCoy.

Locality and horizon.—Bed e, Otamita (Hokonui Hills) ;
also in the Mytilus-problematicus Bed at Eighty-Hight Valley,
near Nelson, and in the Pseuwdomonotis-richmondiana Bed on the
south side of the Hokonui Hills. Carnie and Noric. It seems to
be widely distributed, but is scarce and, as a rule, poorly preserved.

LAMELLIBRANCHIATA.

The New Zealand Triassic Lamellibranchs are of considerable
interest. An edentulous shell with a general resemblance to Cardio-
morpha I place, for want of contrary evidence, among the Palzo-
econchs. Taxodonts are represented by Palgoneilo, Leda, and
Macrodon. Forms of great zonal value occur among the Aniso-
myarians, of which Daonella indica fixes the Ladino-Carnic horizon,
several forms of Halobia the Carnic, while great masses of Pseudo-
monotis indicate the Noric horizon. The Alpine form, JZonotis
salinaria, also seems to occur; but the exact horizon which it
occupies in New Zealand is not yet determined. Mytilus (7)
problematicus is an important fossil in the Carnie beds, hitherto
found only in the South Island, but it recurs in New Caledonia.
Forms of Casstanella, Pinna, Pecten, Limatula, ete., also occur.
A series of curious and very variable more or less Lima-like
Myalinidz is common in the Carnic. These forms show affinities
with Pergamidia, Mysidia, and Mysidioptera of the Upper Trias
of Asia Minor and the Alps, and I have applied to them the new
generic name Hokonuia.

The Schizodonts include Megalodon and several species of
Myophoria, one of which has hitherto been mistaken by New
Zealand geologists fora Trigonia. The genus Anodontophora, of
which at least three species occur, seems to be a Schizodont, the
dentition of which has become obscure or obsolete. The Eulamelli-
branchiata are represented by Palcocardita, Pleurophorus, and
possibly Anzsocardia.

CAaRDIOMORPHA (?) NUGGETENSIS, sp. nov. (Pl. XXI, fig. 7.)

Shell thin and platy in structure. Valves apparently equal in
size, edentulous; beaks very anterior, pointed, close together, and
incurved. Hinge-area long and slightly arched. Beneath the
beaks there is a sunken false lunular depression. The valves are
closed all round, except in the depression below the beak, where they
gape to a slight extent for a short distance, apparently in order to
allow the passage of a byssus. The surface is decorated with broad

190 DR. C. T. TRECHMANN ON [vol. Ixxin,

irregular growth-ripples, especially towards the beaks, but is other-
wise smooth. Anterior margin nearly straight, lower margin gently
rounded, and hinder margin obelen the hinge- line voundecr

An adult shell is 49 mm. long, 36mm. high, and the two valves
are 24mm. thick.

A young specimen is shorter relatively to the height than the
adult, measuring 18 mm. in length and 15 mm. in height.

Locality a nd hor izon._ Nugget Point, in a loose block
washed out of Carnic beds in the cliff-section. I collected four or
five specimens.

Remarks.—It is with considerable reserve that I refer this
edentulous shell to the Paleoconch genus Cardiomorpha. The
shape of the young shell, however, suggests this genus. The gape
below the beak apparently precludes it from belonging to the group
of Anodontophora; while the laminar structure of the shell and
the byssal gape suggest that it may be a Myalinid.

PALEONEILO OTAMITENSIS, sp. nov. (PI. XXI, fie. 21.)

The shell is rather thick; anteriorly the valves are somewhat
strongly inflated, but they tend to flatten out posteriorly. The
beaks are rather prominent, anteriorly situated, and directed
forwards. The margin is well rounded in front, gently curved
below, and is produced, narrowing gradually behind. ‘There is
no trace of a posterior ridge on the shell, the surface of which is
gently rounded and smooth. The concentric growth-lines are fine,
evenly spaced, and very regular. When the hinge-line is scraped
away, a row of many teeth is seen behind the beak, with about
six much larger teeth in front of it. Length=17 mm.; height=
9 mm. ; depth of right valve=3 mm.

Locality and Thesiger all c, Otamita. Carnie. I col-
lected several specimens with the shell on them.

Yemarks.—The comparatively-smooth surface of this shell
suggests that of P. elliptica Goldfuss, from St. Cassian; but the
beaks are more anterior, and the shell more inflated heceed them.

PALZONEILO cf. pRHacuTa Klipstein. (PI. XXI, fig. 22.)
1895. A. Ber ‘Lamellibranchiaten der Alpinen Trias’ p.143 & pl. xvi, figs.
32-30.

The shell is fairly thick, the beaks situated well forward. The
anterior margin is well rounded, the lower margin gently curved ;
the posterior portion of the shell is produced, and tapers rather
rapidly. The anterior portion of the valves is considerably inflated,
but they flatten out posteriorly. An appreciable blunt ridge passes
from behind the beaks to the lower posterior margin. ‘The con-
centric growth-ridges are well marked and fairly regular; a few of
the furrows between them are wider than the rest. Length=
18 mm.; height=10 mm.

Locality and horizon.—Bed c¢, Otamita (Hokonui Hills).
Carnic. I collected two or three fine specimens with the shell on
them.

part 3] THE TRIAS OF NEW ZEALAND. 191

Remarks.—This form agrees fairly well with P. preacuta from
St. Cassian, but differs in having the beaks rather more anterior.
It comes nearest to Bittner’s fig. 34, yet the differences hardly
seem to warrant a new specific name for it.

LEDA SEMICRENULATA, Sp.anowae Cel XOX, fies 20))

Shell rather thick; beaks broad and low, situated about the
middle of the shell, and directed slightly backwards. The anterior
margin is well rounded, the outline forming almost a semicircle ;
the lower posterior margin of the shellis produced upwards, and the
hinder part is rostrate. The decoration consists of about forty-five
rather sharp concentric ridges which are fairly regular on the
anterior portion; but near the beaks and on the posterior half,
though remaining constant in width, they become curiously wavy
and broken, producing a crenulated appearance. A blunt ridge
passes from the beaks to the lower end of the rostrate hinder
margin. Length=—18 mm.; height=13 mm.

Locality and horizon.—Bed ¢, Otamita (Hokonui Hills). I
collected two or three specimens with the shell on, but all rather
crushed.

Macropon ef. curtonit Bittner. (Pl. XXI, figs. 12 & 18.)
1895. ‘ Lamellibranchiaten der Alpinen Trias’ p. 121 & pl. xv, fig. 16.

Shell fairly thick. The hinge-margin is straight, and is pro-
duced in front of the beak, terminating rather sharply where it
jos the gently-curved and retreating anterior margin. About the
middle of the lower margin, which is nearly straight, the shell
is contracted by a shallow sulcation extending almost to the
beak. The concentric growth-lines are well marked, but irregular.
Behind the beaks there is a faint trace of radial ribs interrupted
by the growth-lines. Length=about 33 mm.; height=13 mm.

Locality and horizon.—Bedc, Otamita (Hokonui Hills). I
collected a left valve there with the shell preserved, but damaged
at both ends. The New Zealand Geological Survey possesses the
internal casts of two specimens from Mount Heslington (Nelson),
showing the characteristic dentition; but they are not specifically
determinable, though probably belonging to the same species.
Carnie.

Remarks.—At least one species of Macrodon occurs in the
New Zealand Trias, but the shells are scarce. My specimen
resembles rather closely the above-named species from the Raibl
Beds of Lake Iseo (Lombardy). It recalls also a closely-related
form, IW. esinensis Stoppani, from the Esino Limestone, which
Bittner figures on the same plate, figs. 17 & 18.

PsEUDOMONOTIS AND MOoNorISs.

The MMonotis-like shells, which Hochstetter brought from Rich-
mond, near Nelson, were identified by Zittel as a variety of
Monotis salinaria and ealled var. richmondiana. The fact that

192 DR. C. T. TRECHMANN ON [ vol. Ixxiu,

they possess an anterior byssal notch in the right valve, which is
wanting in the true JZ. salinaria, was pointed out by Teller,! who
consequently placed them in the genus Pseuwdomonotis.

I have found this byssal ear and notch in all the New Zealand
specimens that I examined, except in those that oceur in lme-
stone at Okuku. Jn some cases the rock must be carefully cut
away to show it; but it is always present, except in the case just
mentioned. In the large flat varieties of Psewdomonotis ochotica
the ear and notch are reduced to the smallest possible size.

F. Frech? thinks that the three circum-Paciftie species of Pseudo-
monotis: namely. Ps. ochotica, Ps. richmondiana, and Ps. sub-
circularis, are varieties of one andthe same shell. He believes that
Ps. richmondiana oceurs in two forms, and figures and describes.
a new form as var. truncata, pointing out its resemblance to
Ps. ochotica var. sparsicostata. He also considers Ps. subcir-
cularis identical with Ps. ochotica var. sparsicostata.

Ps. richmondiana has been recorded only from New Zealand
and New Caledonia. Ps. subcircularis is a British Columbian,
Californian, and South American Cordilleran form, and characterizes.
the Noriec Beds. Ps. ochotica was first discovered at Verkhoyansk
in Arctic Siberia, in beds of Norie age. It was found later in
Japan,? where it occurs in beds very near the top of the Trias
and a very short distance below the overlying Jurassic. It is also
recorded from Central Timor, where a specimen of Ps. ochotica vay.
densistriata was found in a pebble in the Talau River.*

I now record Ps. ochotica, as defined by Teller, for the first time
in New Zealand. It is a very variable species, but an even greater
range of varieties is present among my specimens than among
those from Arctic Siberia figured by Teller and Mojsisovies.

Near the head of Garden Gully, on its western slope a mile
south-west of the Wairoa Gorge, in the Nelson area, I was for-
tunate in finding a bed of fine-grained dark greywacke-mudstone,
containing a large series of forms which undoubtedly belong to the
Asiatic fossil Ps. ochotica. The beds seem to occupy the middle
limb of a syneline, or possibly a faulted syncline of the Trias, and
are, I think, the highest Triassic rocks exposed in the Nelson
district. In this district the varieties of Ps. ochotica occur in the
bed in Garden Gully to the exclusion of Ps. richmondiana. The
typical Ps. richmondiana occurs in vast numbers in a bed exposed
some distance away on the opposite slope of the valley to the east;
but the two forms are clearly separated, and I have little doubt
that Ps. richmondiana occurs ata lower horizon than Ps. ochotica.

The felspathic sandstone at Richmond, 5 miles north-east of

' Bibliography, 35, p. 104. It is clear that the genus Pseudomonotis does.
not represent a natural group. The Psewdomonotis forms of the Upper Trias
are much more closely related to Monotis salinaria than they are to shells
called Psewdomonotis in the Permian or Jurassic, such as Ps. speluncaria or
Ps. echinata. .

* Bibliography, 18, pl. lxviil.

3 Bibliography, 33, p. 175. 4 Bblicgraphy, 49, p. 189.

part 3] THE TRIAS OF NEW ZEALAND. 193

Garden Gully, contains only Pseudomonotis richmondiana. Near
Albatross Point, in the Kawhia district, the dark shales underlying
the Rhetic Series, close to an igneous intrusion, contain the large
flat Ps. ochotica var. densistriata and a form approaching var.
pachypleura, while Ps. richmondiana seems to be absent, a fact
which further goes to indicate the higher position of the Ps.-ochotica
horizon. I have seen no Ps. ochotica from the Hokonui Hills,
but Ps. richmondiana occurs at various places in that district.
Okuku is the only locality in New Zealand where the Jlonotzs-like
shells form a limestone. Though it seemed unlikely to me that
the Alpine Monotis salinaria should occur in New Zealand, yet
it is not an impossible contingency. Wanner,! who paid great
attention to the differences between this shell and the large flat
forms of Ps. ochotica, records its occurrence in the island of
Serang.

I have already stated, in discussing the Okuku locality, that I
am compelled to regard the shell which occurs there as belonging
to the Alpine form Monotis salinaria.

PsEUDOMONOTIS ocHOTICA Teller. (Pl. XIX, figs. 1-8.)
1886. E. von Mojsisovies, ‘Arktische Triasfaunen’ p.116 & pl. xvii, figs. 1-15,

pl. xvi, figs. 1-11.
1907. J. Wanner, ‘ Triaspetrefakten der Molukken’ p. 189 & pl. viii, fig. 9.

This is a very variable species, and Mojsisovics and Teller have
carefully described and illustrated from the original locality at
Verkhoyansk in Arctic Siberia five varieties, in addition to the
form which they regard as the normal type. These they have
called vars. densistriata, eurhachis, ambigua, pachypleura, and
sparsicostata.

In the one bed at Garden Gully, near the Wairoa Gorge, I
collected specimens more or less closely comparable .with all these
varieties, and, in addition, a form still more strongly arched and
ribbed than any that are recorded from the original locality,
which I have ventured to institute as a new variety under the name
acutecostata. All the varieties occur indiscriminately mingled
together in one and the same rock.

It is not necessary here to recapitulate the description of the
different varieties as given by Teller; but I may say that the large
flat Salinaria-like variety densistriata (fig. ‘1) oceurs in very
characteristic form, and that some of the specimens approach the
North American form Pseudomonotis subcircularis in the expan-
sion and rounded outline of the anterior margin.

The posteriorly elongate and expanded, coarsely-ribbed variety
pachypleura (fig. 3) occurs together with a form presenting a
more or less quadrilateral margin, which Teller calls var. ewrhachis
(fig. 5). The variety sparsicostata, approaching in character the
large and nodosely-ribbed form of Ps. richmondiana, which

1! Bibliography, 49, p. 190.

194: _ DR. C. T. TRECHMANN ON [ vol. Ixxiui,

Frech calls var. truncata, can also be identified among the New
Zealand shells (fig. 4:

A small, dwarfed, anid strongly-ribbed ees in which the right
valve is often strongly arched and bent downwards towards the
margin, very similar to the variety that Teller calls ambigua
(fig. °9), also occurs in association with all the other varieties.

it may here be emphasized that I regard these different forms
as representing individual variants in one very variable species,
since some confusion or misuse of terms may arise in calling them
varieties. However, in describing the following form as var.
acutecostata nov., 1 am merely following the plan adopted by
Mojsisovies and Teller, who describe the specimens of ditferent
shape from Verkhoyansk and Japan as varieties.

Var ACUDECOSTATA, nov. \(CPie XOX hose)

The left valve is strongly arched, the beak is pointed, tapers
rapidly, and is acutely bent over the hinge-area. The outline of
the shell is angular, and there are about fourteen primary ribs,
some of them very acute and prominent, others lower and more
rounded. Other very much smaller secondary ribs appear about
halfway between the ‘beak and the margin.

Locality and horizon.—Garden Gully, south of the Wairoa
Gorge (Nelson), on the western slope of the valley, where all the
varieties occur. On the coast, south of Kawhia, towards Albatross
Point, where the varieties denszstriata and pach ypleura occur.
Upper Noric.

I collected a large series of examples at Garden Gully and
several at Kawhia. The Geological Survey possesses several
specimens of the different varieties from the Nelson district,
but the exact bed whence they came is not identified.

Remarks.—The geographical distribution of this form has
already been discussed. It has not yet been recorded from New
Caledonia.

PsEUDOMONOTIS RICHMONDIANA Zittel. (Pl. XIX, figs. 9a & 9D.)

1864. ‘ Palaontologie von Neu-Seeland’ p. 26 & pl. vi, figs. 1 a-1e.

This species has an oval and gently rounded outline, and the
margin is never angular as it is in some of the fos. Ok sks,
Alien re. nor does the shell show the extremes of variation
exhibited by the individuals of that species. The byssal notchand
ear in the right valve are small, but well developed; the left valve
is gently arched and rounded, the right nearly flat. The ribs are
regular on both valves, being str aight or slightly curved. Fainter
secondary ribs occur yee the primary ribs, and commence a
short distance from the beak. There are about twenty-eight ribs

on the left valve.
Frech! describes a form under the name var. truncata, and

1 Bibliography, 138, p. 506 & pl. lxviii, figs. 4c—-4d.

part 3] THE TRIAS OF NEW ZEALAND. 195

remarks that it approaches very closely to Psewdomonotis ochotica
var. sparsicostata. I have a mass of felspathic sandstone from
Richmond, with a specimen on it which seems to agree with Frech’s.
variety. It certainly resembles the variety of Ps. ochotica, but it
seems to me to be merely a more fully-grown example of Ps.
richmondiana, m which the ribs have become nodose towards the
margins, where they are interrupted by coarse growth-lnes. . It
retains, however, the characteristic rounded outline of this species:
it measures 81 mm. in length and 65 mm. in height.

- The more common form, however, is smaller. The Geological
Survey possesses a very fine specimen with the two valves together,
which is illustrated (figs. 9a & 96). It is 45 mm. long, 37 mm.
high, and 11 mm. thick, and comes from the eastern slopes of
Mount Heslington, near Garden Gully.

Locality and horizon.—Richmond, and the eastern slope of
Garden Gully in the Nelson district; also in the Hokonui Hills.
It is wanting in the coast-section at Nugget Point. It occurs in
enormous quantities in more or less decomposed felspathic sand-
stone, and marks a Norie horizon apparently below that of
Ps. ochotica. In only one case did I see any other fossil associated.
with it, whereas I found several gasteropods and brachiopods in
the Pseudomonotis-ochotica Bed in Garden Gully. It is recorded.
from New Caledonia.

Movorts sarivarta Bronn. (PL. XIX, fig. 10, & Pl. XX, figs. 1-3.)

1830. Leonhard & Bronn, Jahrb. f. Min. &c.%p. 284 & pl. iv, fig. 1.
1907. J. Wanner, ‘ Triaspetrefakten der Molukken’ p. 190 & pl. ix, figs. 2-4.

Among the Monotis-like shells that occur at Okuku the right
valves are nearly as convex as the left, whereas in most specimens
of Pseudomonotis in New Zealand the right valve is nearly flat or
even slightly concave. Also, as already stated, no trace can be
seen of the anterior byssal notch and ear which occur in the right
valve of Psewdomonotis.

For some unapparent reason the shells in this limestone-bed tend
to vary in a manner analogous, though to a less extreme degree,
to the variation in those of Psewdomonotis ochotica. The word

‘variety,’ therefore, is to be understood in the same sense as that
in which I have used it in discussing the last-named species.

The variation tends to produce a reduction in size from the large
flat form which may be regarded as the normal form, accompanied
by a progressively strong “arching of the valves, especially of the.
left valve, without, Moweven any increase in the size of the ribs.

Mownoris sattnaria. (Pl. XIX, fig. 10.)

The largest specimen that I examined is a left valve 70 mm.
long and 57mm. high. It has twenty very regular, equidistant,
straight, or slightly- curved primary ribs, which radiate from the
beak ; between these occasional fainter secondary ribs appear at

196 DR. C. T. TRECHMANN ON (vol. Ixxiu,

various distances from the beak, and near the margin they attain
almost the strength of the primary ribs. This form seems to re-
semble in every way the typical Alpine Wonotis salinaria.

Var. InTERMEDIA, nov. _ CPI. XX fies 1.)

This seems to be a fairly-constant variety: the left valve is
rather strongly arched, and has sixteen narrow and very regular
primary ribs, between each of which in one specimen that I examined
fainter secondary ribs occur at various distances from the beak.
In another left valve the primary ribs are rather broader, and
become nodose towards the lower margin, owing to interruption by
the growth-lines; and very faint, in some cases scarcely perceptible,
secondary ribs occur between the primary ribs, commencing about
halfway between the beak and the lower margin. Length=46 mm. ;
height=37 mm.; depth of left valve=14 mm.

Var. HEMISPHERICA, nov. (Pl. XX, figs. 2 & 3.)

Shell small, the left valve very strongly arched and rounded; the
beak is inflated, and projects beyond the hinge-line, which is very
short. The margin is rounded and contracted i in oe but rather
produced behind. There are about seventeen regular, low, rounded
primary ribs, more or less equal in size, between which an occasional
very faint secondary rib occurs towards the lower margin. A right
valve is rather strongly arched, but much less so than the left; the
beak is pointed and not inflated; and the hinge-line is short, with a
faint posterior wing. There are about fifteen primary ribs, more or
less equal in size, but rather irregularly spaced; and in the two
widest spaces about the middle of the shell a very faint secondary
rib oceurs. A left valve is 22mm. long, 22mm. high, and 12mm.
deep. A right valve is 23 mm. long, 19mm. high, and 9mm. deep.

Locality and horizon.—Okuku (Ashley County), in the
Canterbury Alps, in hmestone. Horizon uncertain, Carnic or Noric.
All the specimens that I examined belong to the New Zealand
Geological Survey, and were collected by Mr. McKay in 1879.

Remarks. —Monotis salinaria is generally a Norie fossil, but
occurs in Europe also in Carnic beds. It ranges from the Alps and
Sicily through Afghanistan, Baluchistan, the Pamirs, Himalayas,
and Borneo to the Moluccan Islands, and is now recorded for
the first time from New Zealand as distinct from the genus
Pseudomonotis.

DaoneEtya inpica Bittner. (Pl. XX, fig. 7, & Pl. XX, fig. 5.)

1899. ‘ Trias Brachiopoda & Lamellibranchiata’ Pal. Ind. ser. 15, vol. iii, pt. 2,
p. 39 & pl. vii, figs. 4-11.

1907. J. Wanner, ‘ 'Triaspetrefakten der Molukken’ p. 202 & pl. ix, figs. 8-9,
pl. x, figs. 2-3.

The outline is rounded so far as one can ascertain, since most of
the specimens are broken prior to fossilization. The hinge-margin
is straight: the beak projects slightly above it, and is situated about

part 3] THE TRIAS OF NEW ZEALAND. 197

the middle of the hinge-margin. ‘There is no anterior ear as in
Halobia, and consequently there can be no doubt that this shell
belongs to the genus Daonella. The ribs commence near the beak,
only a small area of which is free from them, and sweep reg alarly
down to the margins. Secondary furrows commence some distance
from the beak, but do not reach the depth of the primary furrows,
and it is only occasionally that a rib is divided by two furrows.
Concentric ripples are confined to the umbonal regions, and
growth-lines are scarcely seen. There is a very narrow triangular
space extending along the posterior hinge-margin, which is free of
ribs. It attains a considerable size: a fragment of a large
Specimen in my collection (Pl. XX, fig. 7) shows that it must
have been about 70 mm. long and 60 mm. high.

Locality and hori zon.—In New Zealand th's form is con-
fined to the Kaihiku Beds, and affords very strong evidence that °
these are of Ladinic or Lower Carnic age. It seems to occur in
all the localities where the Kaihiku Beds are found. I collected
‘several specimens in the Caroline Cutting on the south side of the
Hokonui Hills, and on looking over the Geological Survey Collec-
tion I identified many specimens from the Nelson district, Mount
Potts, and other localities.

Remarks.—This is the only member of the Daonella! and
Halobia group that occurs in the Kaihiku Beds, and seems to be
in every way identical with the Himalayan form. It belongs to
the group of D. tyrolensis of the classification of Mojsisovies, from
which it differs in details well defined by Bittner. It resembles
also in some ways L). sakawana Mojsisovics, a Japanese fossil. It
is widely distributed in the Himalayan Trias, and in the Shal-
Shal section and other localities, occurs in a bed which Diener took
to be the top of the Muschelkalk complex, but later attributed to
the donoides Beds. Wanner? records it, figuring specimens from
the southern coast of Timor, and regards it as marking the base
ot the Upper Trias. This form has not been recorded from New
Caledonia. In the Spiti district of the Himalayas? it is associated
with D. lommeli, a well-known Alpine Ladinic fossil.

Hatopia zirrect Lindstrom, var. zEALANDICA, nov. (Pl. XX
fig. 6, & Pl. XXI, figs. 1-2.)

Beak rather prominent, somewhat inflated, directed forwards, and
situated rather in front of the middle of the straight hinge-line.
The anterior ear is broad and well marked, triangular in outline ;
it widens out rapidly, and is strongly arched and rounded. ‘This
ear is marked off from the rest of the shell by a broad shallow sulcus,
‘The radial ribs begin just below the beak as a series of closely-set,

‘ The fossils which Zittel identified as Halobia lommeli were later described
by Mojsisovics as Halobia hochstetteri. H. lommeliis really a Daonella. The
true D. lommeli, a Ladinic fossil, does not seem to occur in New Zealand, the
Kaihiku horizon being apparently too high for it.

2 Bibliography, 49, p. 202. 3 Bibliography, 10, p. 11 & pp. 143-45.
Q. J.G.8. No. 291. R

198 DR. C. T. TRECHMANN ON [ vol. ]xxii,

very faint, raised, rounded lines, which are produced regularly
downwards and backwards with a sheht anteriorly-concave bend.
Some distance below the beak they et out, become wavy, and
bend suddenly forwards, continue thus for a Shore distance and then
bend downwards again less abruptly, passing towards the lower
and anterior margins. In some specimens the hinder portion of
the shell is almost smooth, in others the ribs continue in fairly-
straight though wavy lines, between which a series of shallow

furrows of very irregular width are produced. On the anterior ear

the faint radial ace are sometimes seen on the portion bordering
the hinge-line. Concentric growth-ripples are well marked in the:
region of the beak, but are broad, shallow, and irregular in width.
They are also developed on the anterior ear, but to a less extent.
Secondary ribs appear intercalated between the primary ribs on
the posterior portion of fully-grown shells. The marginal outline
is difficult to construct, as the shells are nearly always im-
perfect ; but the anterior ear projects beyond the lower anterior
margin and is well rounded, and the margin retreats below it, at
least in the right valve. Under the ear the margin is well rounded,
the lower margin seems fairly straight or gently rounded, and the
posterior margin broadly rounded.

This species attains a large size; the biggest example that I col-
lected, when perfect, must have measured eeu 65 mm. in length
and 42 mm. in height.

Locality and horizon.—Large specimens are rather common
in brown, decomposed, fine-grained greywackes on the crest and
saddle of Mount Heslington, south of the Wairoa Gorge, Nelson.
It occurs also in Bed e in the Otamita section, Hokonui Hills, and
I found some small examples in hard greywackes at Nugget Point,.
above the Mytilus-problematicus Bed. I collected specimens in
various stages of growth in all these localities. Carnie.

Reman e ele iuins large and variable fHaloblia falls into the
group of LH. fallax ot the classification of Mojsisovics. The New
Zealand form seems to partake of the characters, both of A. z7tteli
Lindstrém and of H. superba Mojsisovics. The sudden forward
bending of the ribs occurs nearer the beak than in H. superba, but:
somewhat farther away than in H. gittelv. The ribs are less.
numerous than in AH. superba, but they become wavy in the
anterior portion of the shell, iene seems not to be the case in
H. zitteli. However, the aon here described seems to be nearer’
to H. zitteli than to H. superba, and I am inclined to regard it
as a local variety of the former species.

H., zitteli comes from the Trias of Spitsbergen, where it occurs.
in rather high Carnic beds with Pinacoceras ct. floridum. It
also occurs in the Upper Trias of Bear Island, and some forms.
figured as young examples from both these localities closely
resemble some of the Halobias from New Zealand. A. superba
occurs in the Carnie of the Austrian Alps.

part 3] THE TRIAS OF NEW ZEALAND. 199

HALOBIA HOCHSTETTERI Mojsisovics. (Pl. XXI, fig. 3.)

1874. ‘ Ueber die Triadischen Pelecypodengattungen Daonella & Halobia’ p. 32:
& pl. iii, figs. 7-9.

Hinge-line straight, the beak directed forwards, not very pro-
minent, and situated rather in front of the median line. The
anterior ear is triangular in shape and widens rapidly, is not inflated
or rounded, and is marked off from the rest of the shell by a narrow
and somewhat angular sulcus. The primary radial ribs begin
below the beak, and consist of a series of rather broad flattened
ribs of irregular width, separated by well-marked and rather deeply
cut grooves. On these ribs two or three very much fainter secondary
grooves occur some distance from the beak. At some distance
below the beak (the distance seems to vary in different specimens),
the ribs become wavy and bend very strongly forwards, continue
thus for a short space, and then curve gently downwards again
towards the lower and anterior margin. The hinder portion of
the shell below the hinge-margin is devoid of ribs and almost
smooth, and the ribs become very feeble towards the lower posterior
margin in fully-grown shells. The anterior ear bears a shallow
radial furrow not far below the hinge-margin.

Broad concentric growth-ripples occur on the young shell, but
they are faint and rather irregular, and they tend to occur also on
the anterior ear. Since specimens of any size are almost invariably
broken, I cannot describe the marginal outline with any certainty,
but it seems to have been similar to that of A. zztteli var.
zealandica. ‘This shell also attains a large size: for instance,
a fragmentary specimen in my collection must have been 65 mm.
long and 40 mm. high.

Locality and horizon.—Crest and saddle of Mount Hesling-
ton, Nelson. Bed e, Otamita, Hokonui Hills. It occurs in the
same bed as the last-described form, and I collected several
specimens of it.

Remarks.—Mojsisovics figures three specimens of H. hoch-
stetteri, all of small size, which were apparently brought to Europe
by Hochstetter and had been identified by Zittel as Halobia
lommeii.1 Mojsisovics gives a long and clear description of this
form, of which the following are the main points :—

It is a rather high form, unstriated towards the hinder hinge-margin, with
a wide anterior ear, on which beneath the margin a rather strongly-arched fold
occurs, split at some distance from the beak by a sunken groove. Primary
radial grooves are not numerous, and the ribs that they form are divided at
varying distances, by further single or double grooves, into secondary ribs of
dissimilar width. Near the forward and hinder part smaller ribs occur.
Anteriorly the ribs reach to theear. The ribs do not run straight, but undergo
several bendings to and fro similarly, as is generally the case in the group of
H. fallax. The wavy breaking of the ribs does not take place in all examples
at the same age, and he remarks that it would be interesting to know
whether this corresponds to any difference in geological age. Concentric

ripples are very apparent on the upper half of the shell. Length=13 mm.;
height=10 mm.

‘ Bibliography, 51, p. 27 & pl. vi, figs. 2 a-2c.
R2

200 DE. C. T. TRECHMANN ON _ [ vol. Ixxiti,

From the description it is clear that Mojsisovies only had shells
in the young stage. Some of those that I obtained, and apparently
identified correctly with Halobia hochstetteri, reach a much more
adult stage, and show the sudden forward bending of the ribs.

He goes on to say that Lindstrém rightly considered this form
to be distinct from Daonella lommeli, but erred in identifying it
(though under reserve) with the Spitsbergen form H. zittel7, from
which it is easily distinguished by its less numerous, wider, and
more often wavy ribs. “He compares it with H. rugosa, a form
which attains a wide horizontal range in the European Alps. Bittner!
regards H. hochstettert as more closely related to H. zitteli
than to A. rugosa, an opinion with which I thoroughly agree.

The specimens illustrated by Mojsisovics were said to come from
the JLonotis-richmondiana Beds at Richmond, near Nelson. By
analogy with the Alpine and Spitsbergen Halobias he places this
form high in the Carnic, in which case it should not oceur with
Pseudomonotis richmondiana, a Noric fossil. I never saw any
Halobias in the Pseuwdomonotis Beds in New Zealand, and
Ps. richmondiana generally .occurs entirely by itself. I think,
therefore, that the specimens that Hochstetter obtained must be
from some other locality, possibly the Wairoa Gorge. Arthaber ?
attributes Halobia hochstetteri to a Noric horizon, probably
because of its supposed occurrence in the same bed as Pseudo-
monotis richmondiana.

Hatosia cf. austrraca Mojsisovies. (Pl. XXI, fig. 4.)

1874. ‘ Ueber die Triadischen Pelecypodengattungen Daonella & Halobia’ p. 26
& pl. iv, figs. 12-18, pl. v, fig. 14.

The shell is about as long as it is high; the beak is slightly
directed forwards; the ribs are not very numerous, flattened,
irregular in width, and separated by rather sharply-cut furrows,
some of which are deeper than others. The ribs are finer and
more closely set on the posterior portion of the shell. Near the
hinder hinge-margin a considerable portion of the shell is smooth.
The primary ribs are split at various distances below the beak
into two or four secondary ribs. The anterior ear is rather wide;
it bears one or two faint radiai ribs, and is not sharply SHen
entiated from the rest of the shell. Concentric ripples are most
prominent on the umbonal region, and pass across the anterior ear
as well as over the rest of the shell. A specimen in my collection,
which has the margins somewhat broken, measures about 26 mm.
in length and 24 mm. in height.

Locality and horizon.—Bed e, Otamita, Hokonui Hills,
where I collected three or four specimens, none of them very well
preserved. Carnic.

Remarks.—This shell apparently belongs to the group of
Halobia rarestriata of the classification of Mojsisovies ; 1t comes

1 Bibliography, 6, xlv, p. 254.
2 Bibliography, 13, p. 241.

part 3] THE TRIAS OF NEW ZEALAND. 201

nearest to H. austriaca, which is a Carnie fossil and, in the
Austrian Alps, builds up banks in the limestones with Bucephalus
subbullatus. The flattened ribs of irregular width and the sharply-
cut furrows of the present form recall those of the young shell of
Hf. hochstetteri; but the beak in H. austriaca is less strongly
inclined forwards, also the ribs show no waviness and do not bend
forwards.

HALOBIA spp.

In addition to the three forms of Halobia already described, the
Carnie beds of the New Zealand Trias contain at least two other
smaller and less conspicuous forms, which appear to be distinctive
and probably new species, although from the rather scanty nature
of the material obtained by me I hardly feel inclined at present to
record them as such. As they occur in the same bed at Otamita
and Mount Heslington as the forms just described, and as they
appear to be undescribed species, a description of them cannot add
any further information regarding the horizon of these beds than
that yielded by the forms “which. closely resemble A. zztteli and
HT. austriaca. I may remark, however, that a small Halobia, very
common in Bed ¢ at Otamita, strongly resembles a shell which
Bittner illustrates under the appellation ‘ Halobia, n. sp., aff.
neumayrt Bittner,’ from the Upper Trias of Balia in Asia Minor.
I do not recollect finding the forms allied to A. zitteli or
HI. hochstettert in Bed ¢ at Otamita, and so the small Halobias
mentioned above may characterize a rather higher horizon. Halobia
neumayrt, which occurs at Balia, is a species of the group to
which AH. zitteli and H. hochstettert belong. A careful and
prolonged zonal collecting of the Carnie Halobias of the New
Zealand Trias would probably yield further interesting results.

Myris (?) PRoBLEMATICUS Zittel. (PI. XX, tig. 8.)
1864. ‘ Palaontologie von Neu-Secland’ p. 28 & pl. viii, figs. a-b.

Shell thin, mytiliform, the beaks anteriorly situated, terminal,
the upper posterior margin bluntly alate.

Area straight or shghtly curved; behind the beak is a concave
ligament-groove bearing faint parallel striez. I saw no trace of
hinge-teeth nor of muscle-scars. Some specimens seem to have
a small, narrow, byssal sinus below the beak. ‘There is a small
plate or septum inside the beak. A typical specimen measures
109 mm. in length. The specimen illustrated is a small left valve.

Locality and horizon.—The MAlytilus-problematicus Bed
forms a very constant horizon about the middle of the Carnie in
all the principal sections in the South Island. It has not been
traced in the North Island, but reappears in New Caledonia. The
bed is made up of incredible quantities of separated valves, among
which an occasional valve of Hokonuia, or of the form next to be

202 DR. C. T. TRECHMANN ON [vol. lxxin,

described, occurs. 'The bed is specially well seen at Nugget Point,
where it is about 10 feet thick.

Remarks.—The specific name that Zittel gave to this shell
seems to imply some doubt as to its real affinities. I never found
the two valves together, but the New Zealand Geological Survey
Collection includes one or two examples in this condition, though
not well enough preserved to show whether it is an exactly equivalve
shell or not. This, as also the absence of muscle-scar impres-
sions, makes a certain attribution impossible at present, but I
strongly suspect that the form here described may be related to
the Myalinide rather than to Mytilus.

MYyTILUS (?) MIRABILIS, sp. nov. (PI. XX, figs. 9a & 96.)

Shell inflated, very strongly arched ; the valves are nearly twice
as deep as they are long, very much compressed antero-posteriorly.
Beak small, anteriorly situated or terminal; area very short with
a ligament-groove behind it, bearing faint parallel striz. There is
a small apical septum in the interior of the beak. In one specimen
I detected a posterior muscle-scar of fair size, but saw no trace of
an anterior scar. The hinge is edentulous.

Length=652 mm. - height= 108 mm. ; depth of valve=100 mm.

Locality and how 1z0n.—It sane rather commonly in the
Mytilus-prob lematicus Bed at Eighty-EHight Valley, south of the
Wairoa Gorge, Nelson. Carnic.

Remarks.—This shell has been called Gryphea in New Zealand
Geological Survey reports. The valves are always separated, but
T have no doubt that it is an approximately or completely equivalve
shell, as I collected both left and right valves. I feel sure also,
after examining the shell-structure, which is of a laminar nature,
that it is Folaned to Mytilus problematicus, with which it oceurs in
intimate association and with which it scems to be connected by a
series of intermediate forms that may be young specimens. It
suggests, in fact, an enormously overgrown specimen of Mytzlus
pr Tilers in which the valves ive become strongly arched.
Fully-grown examples with the two valves together tust have
presented an extraordinary appearance, quite unlike that generally
associated with JZytilus, a fact which causes me to question the
generic attribution both of this and of Mytilus problematicus.
The holotype is a right valve in my collection. The New Zealand
Geological Survey possesses several specimens from Highty-Hight
Valley. This form generally occurs in a poor state of preserva-
tion, with the shell more or less completely dissolved away.

Hoxonvta, gen. nov. (Pl. XX, figs. 4-56; Pl. XXII, figs. 1-5.)

The shells belonging to this genus show very considerable
diversity in size, shape, degree of inflation, thickness of shell, and
situation of the beak. Some recall Zima in general shape, others
Myalina or Avicula.

The shell-structure is more or less platy and foliaceous, recalling

part 3} THE TRIAS OF NEW ZEALAND. 203

in this respect that of the Australian Permo-Carboniferous genus
Eurydesma. The hinge seems to be quite edentulous, and the
articulation was so feeble that the two valves are always discon-
nected; but I have a few specimens in which the valves are only
displaced shghtly, and they obviously belonged together. From
these it is evident that the valves were approximately equal in
size and degree of inflation, although whether the valves were
exactly equal or not is not clear. Jam inclined to think that the
left valve may have been slightly smaller than the right.

The hinge-line is straight or very shghtly curved, and is less
than the greatest width of the shell. Behind the beak in both
valves is a longitudinal. concave, areal furrow, which extends for
about two-thirds the length of the hinge-margin, and seems to
have accommodated a partly sunken ligament. There is a small,
blunt, thickened septum in the interior of the apex of each valve,
recalling that in Myalina or Dreissensia. Behind the beaks
Is a flattened, obtusely-angular, posterior wing, which in some
examples is but slightly ditferentiated from the hinder margin of
the shell.

The anterior portion of the shell in front of, or below, the beak
differs markedly in the right and left valves, and shows features
which are common to all the species of the genus whatever may
be their shape or degree of inflation.

The right valve immediately below the beak bears a strong curved
or semicircular truncation, which is bounded on the posterior
side by a rounded, raised or thickened ridge of shell. In front of
this truncation, and just below the apex, is a rather long tongue-
shaped projection (Pl. XXII, figs. 1, 2a, & 26), and immediately
below this is a conspicuous retreat of the shell- margin forming
a deep and marked sinus. The upper edge of the anterior toneue-
like shelly process carries a raised or thickened ridge.

In the left valve no concave truncation is seen in front of the
beak as in the right valve ; but below the beak the shell-margin
is arched and thickened, and retreats so as to produce a narrow
byssal opening similar to that of Mytilus or Myalina (Pl. XX,
fig. 5D).

The tongue-like process of the right valve projects beyond the
plane of junction of the valves, and must have covered the upper
part of the opening produced by the retreat of the margin of the
opposing left valve. The opening which remained beneath the
process when the two valves were together seems to have allowed
the passage of a byssus.

In one example (Pl. XXII, fig. 2a) a fairly-large posterior
muscle-scar is observed rather more than halfway down the shell
between the median line and the posterior margin; but I could see
no trace of an anterior scar, and in nearly all the specimens the
muscle-impressions are quite obscure. One cannot therefore say
with certainty whether the genus is monomyarian or dimyarian.

- Dimensions.—The specimens are extremely variable in size,
and this feature, together with the shape, will be noticed in the
specific descriptions.

204 DR. C. T. TRECHMANN ON [ vol. Ixxiii,

Material.—TI collected some twenty-five specimens, severa] of
which bear a portion of the shell. The New Zealand Geological
Survey has many specimens, mostly in the form of casts. ‘They
gener ally occur in a very unsatisfactory state of preservation, with
most or all of the shell dissolved away.

Locality and horizon.—The genus seems to be confined to
the Carnie beds and occurs in all localities, such as the Nelson
district, the Hokonui Hills, Nugget Point, ete. Separated valves.
are found in the Mytilus-problematicus Bed.

Affinities.—I found considerable difficulty in ations to
determine the relationship of these curious bivalves. The anterior
_ tongue-like projection of the right valve appears to be homologous.
with the anterior auricle of the Myalinide, to which group “the
genus seems to belong. The anterior retreat or thickening of the
margin of the left valve below the beak resembles that of Per-
gamidia Bittner,! a genus which oceurs in the Upper Trias of
Baha in Asia Minor : but in Hokonuia it extends over a less.
distance of the anterior margin than it does in Pergamidia.

The genus Mysidia Bittner? occurs also in the Upper Trias of
Balia; but only right valves were known to Bittner, and they have
a prominent tooth beneath the beak.

Hokonuia also recalls the genus Wysidioptera Salomon, a group:
of bivalves described as Mytiloid Limide, which occur in the
Upper Trias of the Alps and other regions. In these, however,
according to Bittner’s illustrations, the byssal opening is sunilar in
both valves. Asa result of later research, however, Bittner shows.
that in Jysidioptera the area of the right valve is higher than
that of the left.

The anterior ear of the right valve in Hokonuwia recalls in some
ways that which characterizes the left valve of Eurydesma, a form
occurring in the Permo-Carboniferous marine beds of Australia
and other regions of Gondwanaland.

As I can find no genus closely comparable with these New
Zealand shells, I am compelled to institute a new generic name for
them, and to regard them as having affinities with Pergamidia,
Mysidia, and Mysidioptera, three Lima-like Myalinide of the
Upper Trias of the Alps and Asia Minor.

It seems that a considerable number of species oceur in New
Zealand; but, owing to the poor state of preservation of the material,
it is very difficult to separate these, or accurately to diagnose them.
I offer descriptions of two species which seem to be the commonest:
and most distinctive.

HOKONUIA LIMEFORMIS, sp. nov. (PI. XXII, figs. 24,26, &5;
Pl. XX, fig. 4)

Shell rather higher than long, hinge-line straight, measuring
about two-thirds of the length of the shell. Beak 1ather pointed,

1 Bibliography, 6, xli, p. 103 & pl. iii, figs. 1-4.
2 Ibid. p. 113 & pl. ii, fig. 10.

part 3] THE TRIAS OF NEW ZEALAND. 205

anteriorly situated and directed forwards, not projecting above the
hinge-line. There is a curved truncation in front of and below
the beak of the right valve, which extends for about a third of the
length of the anterior margin and is bounded posteriorly by a raised
ridge, on and behind which three or four faint radial ridges occur.
The tongue-like projection of the right valve is directed towards
the opposite valve at about a right angle from the plane of the right
valve. - The posterior wing is “angular and flattened. The hinder
margin is gently curved, ‘the anterior margin more rounded, and
the lower margin is well rounded. The or owth-lines are prominent
and irregular, and the surface of the shell towards the lower margin
tends to become wavy and irregular.

Height=75 mm.; length = ‘58 mm. ; length of the hinge-area=
27 mm.; depth of right valve= 18 mm.

Locality and horizon.—Bed c, Otamita, Hokonui Hills.
Carnie.

Remarks.—This is the most ZLima-like of these shells, and
recalls in general outline the recent Lima excavata. I have three
right valves, all with portions of the shell; one of them with
the left valve attached but lacking the beak; and a separated
left valve.

HOKONUIA ROTUNDATA, sp. nov. CR XX, ties! o@ & oO;
Pl. XXII, figs. 1, 3, & (2) 4a, 45.)

Shell fairly thick; valves rather inflated and gently rounded,
about as high as wide. Hinge-line considerably less than the width
of the shell. he beak projects somewhat above the hinge-line,
and is situated about the median line or rather in front of it. The
posterior wing is rounded in outline, and is scarcely differentiated
from the hinder margin of the shell, which is gently rounded.
The anterior margin is rounded and rather produced, and the lower
margin is gently rounded. ‘There is a short, anterior, semicircular
truncation below the beak of the right valve.

Growth-lines are well marked, and irregular ripples of growth
occur especially towards the margin.

The anterior tongue-like process of the right valve is directed
forwards, rather than directly downwards, away from the right
valve.

A specimen with both valves measures 89 mm. in height and
84mm. in length; the right valve is 21 mm. deep, and the hinge-
line is 85 mm. long.

Loeality and horizon.—Hokonui Hills. I have casts of
two left valves, and another cast in which both valves are slightly
displaced. I collected a left valve with the shell on it in the
Mytilus-problematicus Bed at Nugget Point. The New Zealand
Geological Survey possesses a cast of the anterior part of a right
valve, from which I made.a gutta-percha squeeze. Carnic.

Remarks.—This species is more rounded in outline than the
last ; the anterior truncation of the right valve is less extensive
and more curved; and the tongue- like process is directed more
forwards from the plane of the valve.

206 DR. C. T. TRECHMANN ON (vol. lxxiu,

Pinwa sp. (PI. XXII, fig. 11.)

Shell thin, hinge-line straight, marginal outline broadly rounded.

behind. <A bluntly-angular median ridge passes from the beak to
the lower posterior margin. The concentric growth-ripples are
well marked and closely set. Length=80mm.; height near
posterior margin = 47 mm.

Locality and horizon.—FEighty-Eight Valley, Nelson.
Carnic. The New Zealand Geological Survey Collection possesses
two or three specimens.

Remarks.—This Pinna rather resembles P. heerz, J. Boehm,!

from the Upper Trias of Bear Island.
Pucrmn sp. “CP XX, fe. 1S.)

Shell thin, with comparatively large ears. A great number of
fine, sharp, radial, slightly-wavy ribs start some distance below
the beak, and pass to the margins; between these a number of
exactly similar secondary ribs are developed lower down. ‘Towards
the lateral margins the ribs are somewhat more closely set. About
five rather coarse ribs are present on the ear. The concentric
growth-lines are numerous and closely set, but are fainter than
the ribs. Leng ; height = 28 mm.

Locality and horizon.—Paleocardita Bed, Nugget Point.
Carnic. <A single cast, from which I made a gutta-percha squeeze.

Remarks.—I am uncertain whether this isa left or a right
valve; only one ear is well shown, and it seems different from the
other one. The shell may possibly be an Aviculopecten. The
absence of ribs on the umbonal portion may be due to erosion
during life, or to conditions of fossilization. It recalls in some
respects a Pecten from the Pseudomonotis Beds of Japan figured
by Mojsisovics.?

Lima (Limatuna) cf. PICHLERI Bittner. (Pl XXL, fig. 16.)
1895. ‘ Lamellibranchiaten der Alpinen Trias’ p. 192 & pl. xxii, fig. 21.

Outline oval and rather narrow, hinge-line wide, posterior and
anterior ears about equally developed. Area not visible. It is
decorated with fine, somewhat sharp, and wavy ribs, which pass
from the beak to the margins. This shell agrees with the above-
named species, but is less oblique in outline and the ribs are rather
more wavy.

Locality and horizon.—Western slope of Mount Heslington,
south of the Wairoa Gorge, Nelson. Carnic.

CASSIANELLA sp. (Pl XXI1, fig. 19.)

Shell fairly thick, the beak arched and rolled, projecting above
and rather over the hinge-line. The posterior wing is somewhat

1 Bibliography, 8, p. 38 & pl. v, figs. 4-6.
2 Bibliography, 33, p. 176 & pl. ii, fig. 9.

part 3] THE TRIAS OF NEW ZEALAND. ! 207

produced and pointed. The lower posterior margin is rounded and
slightly produced; the upper anterior margin is apparently well
rounded. The surface-decoration consists of fine, closely-set,
rather foliaceous, concentric growth-lines.

Locality and horizon.—Bed ¢, Otamita, Hokonui Hills.
Carnic. I collected a single left valve; unfortunately, the margins
are somewhat damaged.

Remarks.—This specimen is too imperfect for a specific deter-
mination, but is undoubtedly a Casstanella.

AwnopontopHora. (Pl. XXI, figs. 8-10.)

The three bivalves which will now be described appear to belong
to the genus Anoplophora of Sandberger: this is a preoccupied
name, which Cossmann has replaced by that of Anodontophora,
although, owing to the somewhat uncertain characters of the genus,
the identification is not entirely beyond doubt.

Zittel! says of Anoplophora that the hinge-teeth are wanting,
and that the hinge-margin is somewhat thickened in front of and
behind the beak; the anterior muscular depression is heart-shaped
and wide, the posterior one slightly sunken, and the pallial line is
marginal and linear.

Dr. W. H. Dall? includes Anoplophora in the Cardiniude, and
says that in the right valve there is a blunt, thick, cardinal tooth
fitting into a socket in the opposite valve, and beside the socket a
long posterior lateral tooth.

Bittner? says of the Himalayan form Anodontophora griesbacht
that the test is thin near the umbones, and a slight filing was
sufficient to prove that a strong hinge-plate with tooth-structure
did not exist. He goes on to say that muscular impressions are
tolerably distinct for the thin shell, and that a pallial sinus is not
perceptible.

In my New Zealand examples, which I am able to group into
three species, the shell is completely closed all round; in two of
them it is very thin, but in the third rather thicker. I could
detect no impressions, either of the muscle-scars or of the pallial
line. As regards the dentition, a close examination of all the casts
in my possession showed no trace of hinge-teeth; but there was
evidence of a thickening of the hinge-margin below and behind
the beak.

Locality and horizon.—They seem to be confined to the
Carnic beds in New Zealand. I succeeded in collecting several
Specimens with the shell; but they generally occur as casts, and
are often more or less distorted and crushed. Sir James Hector’s
identification of Hdmondia in these beds seems to have been based
on shells of this group.

1 « Handbuch der Palaontologie’ vol. i, pt. 2, p. 62.

* Zittel’s ‘Textbook of Paleontology’ [trans]. Eastman] vol. i (1913)
p. 452.

3 Bibliography, 5, p. 60.

208 DR. C. T. TRECHMANN ON (vol. xxi, —

ANODONTOPHORA ANGULATA, sp. nov. (PI. X XI, fig. 10.)

Shell thin, elongated; the beaks anterior or terminal, projecting
considerably above the hinge-area, strongly directed forwards,
tapering and rolled, enclosing a deep false lunular depression
beneath them, divided by the sharp margin of the valves. The
anterior margin below the beak is wel! rounded, the lower margin
very gently eee and the posterior lower margin rather angu-
lated. The upper posterior margin is bluntly angular. A rather
prominent angular ridge merging gradually into the surface of the
shell passes an Benin oe cae to the lower posterior margin,
causing the valves to be somewhat inflated. Growth-lines are
fine a closely set, but rather irregular; otherwise the surface is
smooth. Length=31 mm.; height — 20 mm.; thickness of both
valves = 17 mm.

Locality and horizon.—Bed c, Otamita, Hokonui Hills,
where I collected several specimens, both as casts and with the
shell preserved. Carnie.

Remarks.—This form is easily recognized by its elongate shape,
nearly terminal beaks, and the strong ridge: on the posterior
portion of the valves.

ANODONTOPHORA OVALIS, sp. nov. (Pl. XXI, fig. 9.)

Shell very thin; beaks rather anteriorly situated, rounded, broad,
low, anteriorly directed and rolled, enclosing beneath them a deep,
false, lunular depression. The anterior margin below the beaks is
well rounded and rather produced ; the posterior margin is broadly
rounded. The valves are not inflated; the surface is gently rounded,
and shows no ridge in the posterior portion.

The surface of the shell is fairly smooth with fine, but rather
irregular, raised growth-lines, which become more strongly developed
towards the margin. Length=35mm.; height=25 mm.; thick-
ness = 15 mm.

Locality and horizon.—Bed ec, Otamita, Hokonui Hills.
Carnic. I collected three specimens with the shell wholly or
partly preserved.

Remarks.—This species resembles rather closely Anodonto-
phora griesbachi Bittner,| which occurs in the J7 opites Beds of
the Bambanag and Shal-Shal sections of the Himalayan Upper
Trias; but in the New Zealand shell the beak seems wider,
blunter, and more anteriorly situated, and the growth-lines are
coarser and less regular.

ANODONTOPHORA EDMONDIIFORMIS, sp. nov. (Pl. XXL, fig. 8.)

The shell is fairly thick, but seems to have been thinner in the
umbonal region. ‘The beak is rather anteriorly situated, broad
and blunt, anteriorly directed and inrolled, enclosing a small
lunular depression. ‘The margin is well rounded in front, slightly |

! Bibliography, 5, p. 60 & pl. viii, figs. 14-16.

part 3 | THE TRIAS OF NEW ZEALAND. 209

curved below, and broadly rounded behind. he surface of the
shell is gently rounded, with fine, closely-set growth-lines, inter-
rupted in places, especially towards the margin, by a larger growth-
furrow. ‘here is no radial sculpture or ridge. Length=42 mm. ;
height = 29 mm.; depth of the left valve = 11 mm.

Loeality and horizon.—Bed c, Otamita, Hokonui Hills.
I collected a fine left valve and a smaller double-valved specimen,
both with the shell preserved. Carnie.

Remarks.—This form differs from A. ovadis in its much thicker
shell, more elongated shape, and larger size. The fine concentric
growth-lines recall those on a specimen of A. griesbachi illustrated
by Bittner; but the beaks are more anteriorly situated, and the
shell is apparently thicker. J could not ascertain the characters
of the hinge-area in my specunens.

MEGALODON GLOBULARIS, sp. nov. (Pl. XXI, fig. 17.)

Shell thick, rounded, tumid, and inflated, especially towards the
hinder margin; the two valves together form a rather globular
shell. The beaks are anteriorly situated, strongly directed for-
wards, produced to a point, and nearly touch one another. Below
them is a deep, false, lunular depression. The shell-margin
is gently rounded behind and below, but is slightly produced
anteriorly below the lunule. ‘The growth-lnes are closely set and
coarsely marked, and the growth of the shell is somewhat inter-
rupted and irregular. ‘The anterior muscle-scar is fairly strongly
marked.

One specimen is 23mm. long, 27 mm. high, and each valve is
15 mm. deep. A rather smaller right valve is 20 mm. long,
18 mm. high, and 8 mm. deep.

Locality and horizon.—lI collected the casts and impressions
of two specimens (one with both valves together and part of the
shell remaining) on the north side of the entrance of the Wairoa
Gorge in greywackes below the Mytilus-problematicus Bed. The
other, a right valve, occurred a little way up the Gorge in the
Mytilus-problematicus Bed. Lower Carnic. From both of these
gutta-percha squeezes were made.

Remarks.—There seems to be no doubt that this shell is a
Megalodon, the hinge-plate is thick and heavy; but I could not
see the disposition of the teeth, neither could I ascertain whether
the valves were quite equal or not.

PSEUDOPLACUNOPSIS PLACENTOIDES, sp. nov. (Pl. XXJI, figs. 14
& 15.)

Bittner uses this generic or subgeneric name for shells outwardly
resembling Placunopsis, but wherein the hinge-apparatus par-
takes of the character of that of Spondylus or Plicatula, and is
formed by two ridges or auricular crura which diverge below the
beak.

The shell here described comes under this generic definition.

210 DR. C. T. TRECHMANN ON [vol. Ixxiil,

It occurs fixed to the surface of other shells, but seems to have a
partiality for attaching itself to the large Nautilids. The free
or upper valve reproduces the sculpture of the shell to which it is
attached. ‘The lower sessile valve is very thin, and is closely
attached by the whole of its surface. The crura diverge at about
a right angle, and the margin of the valve is marked by a row of
fine radiating furrows. The free or left valve is convex, and the
growth-lines are irregularly spaced and well marked. The hinge-
line is straight, and occupies almost the greatest width of the
shell; but the area is obscure or absent.

Locality and horizon.—Bed ec, Otamita, Hokonui Hills.
Carnic. Prof. P. Marshall collected a large crushed Gr ypoceras,
which had a great part of its surface covered with these shells.

MyYopnoria NUGGETENSIS, sp. nov. (Pl. XXII, fig. 10.)

The shell is sub-triangular in outline. The beaks are situated
slightly forward of the median line, are pointed, close together, and
turned very slightly but perceptibly backwards.

The anterior margin is rounded, the posterior lower margin some-
what prolonged Aaa angular. ‘The keel, which passes from the .
beaks to the lower posterior margin, is prominent, and the two parts
of the shell separated by it make a rather sharp angle one with
the other. The groove in front of and adjoining the keel is very
slightly wider, but no deeper, than the other radial grooves, and »
a line of very small nodes passes down the middle of it. About
eight ridges, broken by the growth-lines into nodes, pass from the
beaks to the lower and anterior margin. Behind the keel the
shell is almost flat, and is covered with fine growth-lnes and
small irregular pimples, which vary in size. A shallow furrow
passes down the middle of the flat posterior portion. ‘The posterior
muscle-scar is suboval and deep on the side nearest the beak, but
shallower towards its lower margin. ‘The pallial impression is well
marked.

The left valve has one very strong central triangular tooth, not
perceptibly divided, but strongly grooved on both sides, eight:
srooves on the posterior and six on the anterior side; there is a very
feeble anterior tooth, strongly grooved on its inner side, and a very
thin posterior tooth scarcely differentiated from the shell-margin,
not grooved. Length=53 mm.; height =47 mm.

Locality and horizon.—About ten specimens, from which
the above diagnosis was drawn up, were obtained from a bed at
Nugget Point, known to New Zealand geologists as the ‘Z'rigonia’
Bed. It comprises about 15 feet of a very hard fine-grained
greywacke rather low in the Carnic, about 700 feet below the
Mytilus-problematicus Bed, and immediately above a thick bed of
granitic conglomerate. The shells occur somewhat plentifully as
single valves, or often with the two valves open or slightly dis-
placed. They are difficult to collect, owing to the hardness of the
rock ; but, by preparation of the material and dissolution of the
shell, satisfactory gutta-percha impressions were obtained.

part’ 3} THE TRIAS OF NEW ZEALAND. yah ls

Remarks.—I was undecided at times whether to regard this
shell as a Trigonia or a Myophoria, but have finally come to the
conclusion that it is a Myophoria. The striation of the hinge-
teeth alone does not apparently make it a Trigonia, although the
very slight but definite posterior inclination of the beaks in some,
“if not all, of the specimens is suggestive of Trigonia.

Two Triassic Trigonte have been recorded. Bittner in 1895.
described Tr. gaytani (Klipstein ) from the St. Cassian Beds,
and placed it in the group of Costate; and J. Boehm in 1903
described a very small form (77. margaritifera) from the Upper
Trias of Bear Island in the Arctic Circle.

MYoPHORIA OTAMITENSIS, sp. nov. (PI. XXII, fig. 8.)

Shell rather small, beaks situated slightly behind the median
line, medially directed. Margin rounded in front and_ below,
slightly angulated behind, but not produced. A raised keel, bearing
seven or eight coarse nodes, passes from behind the beak to the
lower posterior margin. Behind this keel a shallow sulcus passes.
down the flank of the shell, rather more than halfway towards its
posterior margin. The flank is decorated with raised tubercles of
irregular size. In front of the keel, and almost adjoining it, is a
fine raised ridge; in front of this are six very much more prominent:
ridges, which are cut by the concentric growth-furrows into a
series of prominent rounded nodes. The young shell bears a series.
of concentric wavy ridges. Meneth =—is mm-:; hewht = 15 mm,

Locality and horizon. —The holotype is an excellently pre-
served specimen (with both valves and the test preserved) that I
collected in Bed ¢ at Otamita, Hokonui Hills. Carnie.

Fragments of casts, apparently of this shell, are common in the
decomposed felspathic sandstones of the Carnic, near Gore, in the
Hokonui Hills, and other localities. A uth which may be
identical occurs also in Noric beds, but is generally very badly
preserved.

MYoPHORIA HESLINGTONENSIS, sp. nov. (Pl. XXII, fig. 9.)

Shell small and finely sculptured, rounded in front, gently
rounded below, but angulated at the lower posterior portion where
the ridge joins the margin. An acute raised ridge passes from
behind the beak to the lower posterior margin, in front of which
there is a wide sulcus. The middle part of the shell bears six or
seven faint radial ridges, which become progressively fainter as they
approach the anterior margin. These are crossed by a series of
very regular concentric ridges and furrows forming a series of raised
points. Behind the ridge the flank is decorated with fine raised
points. Length=7mm.; height =6 mm.

Locality and horizon.—Mount Heslington, south of the
Wairoa Gorge. Carnic. The holotype consists of a piece of hard
felspathic sandstone belonging to the New Zealand Geological
Agee having three or four casts on its surface, from which I made
a outta -percha squeeze.

212 DR. C. T.. CERECHMANN ON [ vol. Ixxiii,

PALZOCARDITA QUADRATA, sp. nov. (Pl. XXJ, fig. 11.)

Shell thick, strongly arched, with a high rounded ridge passing
from the beaks to the lower or hinder mar ein and merging into the
rounded surface of the shell. Beaks prominent, nee anteriorly
situated, tapering, and rolled. Shell-margin rounded in front,
bluntly angulate behind, and rather less sharply angulate below
where the ridge joins the lower margin. The marginal outline and
the position of the beaks vary somewhat in different examples.
The upper posterior margin is not alate.

Sixteen or seventeen sharp, raised, radial ribs pass from the beak
to the margins, the shallow sunken furrow between them in well-
preserved specimens is marked with very fine, sharp, regular, closely-
set, concentric growth-lines which also cross the ribs. -The anterior
muscle-scar is deep and well marked, and is_ situated closely
adjoining the upper anterior margin.

A left valve from Nugget Point is 20mm. long, 18 mm. high.
A right valve from Otamitais 18 mm. long, 16 mm. high, and 8 mm.
deep.

Locality and horizon.—I collected many specimens with
badly-preserved test in a loose block of very hard, coarse, felspathic
sandstone on the shore at Nugget Point; but I traced the bed in
the eliff where it occurs above the Jlytilus-problematicus Bed.
Valves of Hokonuia sp., gasteropods, etc., occur also in the same
deposit. I found a right valve in Bed ¢ at Otamita with part of
the shell very well preserved. Carnic.

Remarks.—Pale@ocardita 1s now regarded as connected with
the Pleurophoride rather than with the Tertiary and recent
Cardite. The form now described is related to the Alpine forms of
which Bittner records four species in the St. Cassian Beds. It is
as strongly arched as P. benecki Bittner, but is much shorter and
more quadrate in outline. It is more strongly arched than the
common P. crenata Goldfuss, and the upper posterior portion of
the shell is less expanded than in the Alpine species. In the Alps
the Palg@ocardita Beds mark a horizon in the Carnie, and in New
Zealand the genus seems to occupy an analogous position.

PLEUROPHORUS ZEALANDICUS, sp. nov. (PI. XXI, fig. 6.)

Shell thick and solid, oblong and produced behind; the hinge-
line is arched, and the Srbies. of the shell is rounded. The beaks
are very small and anterior, in some specimens terminal, and
scarcely project from the regulariy-rounded anterior outline of the
shell. A broadly-rounded ridge passes from the beaks to the
lower posterior margin, and between this and the hinge-margin
occur two or three faintly-marked ridges. The lunule is obscure,
but there is a long concave escutcheon behind the beaks. The
concentric growth-lines are prominent, closely set, and regular.
The anterior muscle-scar is deep and rounded, and the pallial im-
pression is well marked. Length=63 mm.; height= 25mm.

Locality and horizon.—Bed c, Otomita, Hokonui Hills,

part 3] THE TRIAS OF NEW ZEALAND. 213

where it is common and very well preserved. It also occurs at
Nugget Point and in the Nelson district. Carnie.

Remarks.—This large form recalls somewhat the Permian
Pleurophorus costatus, but is larger, more rounded, and the
hinge-line is more arched.

ANISOCARDIA PARVULA, sp. nov. (PI. XXII, figs. 6 & 7.)

Shell thick, sub-cireular, with rounded margins. Beak shghtly
in front of the median line, not very prominent, but there is a
well-marked lunule in front of it. Five or six irregularly spaced
growth-furrows occur, and about seventeen faint, slightly-arched
ribs pass from the beak to the margin. The ribs are wanting on
the hinder part, and become very faint on the front part, of the
shell. A squeeze of the interior of a right valve shows a strong
cardinal tooth and apparently another tooth in front of this one,
and sockets about equally distant from the beak for an anterior
and a posterior tooth. These sockets occur just above the muscle-
sears; the anterior scar is deep and bounded by a ridge, the posterior
sear is less strongly marked. ‘The lower interior margin of the
valve is crenulated. Length=5°5 mm.; height=5 mm.

This little shell seems to belong to the Cypricardiacex, and, with
Paleocardita and Pleurophorus, forms the third representative of
that group in the New Zealand Trias.

Locality and horizon.—Bed ¢, Otamita, Hokonui Hills.
I also saw traces of it in the Halobia-zitteli Beds at Mount

Heslington, near Nelson. It is a scarce form.

BRACHIOPODA.

The Brachiopoda of the New Zealand Trias afford an interesting
and suggestive study. The Rhynchonellids seem all to belong to
the essentially Upper Triassic group Halorella of Bittner, which
have a more or less pronounced median suleus in both valves.
One species, apparently new, is very common in the Kaihiku Beds,
but becomes much scarcer in the Lower Carnic. I have de-
seribed only two forms of Halorella, but probably more of them
occur. Among the Terebratulids the Paleozoic genus Dielasma
occurs, apparently to the exclusion of all others, in the Kaihiku
Beds, and seems to be represented by two species. It persists
into the Carnic, but becomes much less conspicuous there. In

the Carnie beds the Terebratulids of Mesozoic aspect, devoid of
_ hinge-plate and median dorsal septum, become conspicuous.!_ There
are several species, one of which is much thickened in the umbonal
region and bears very thick hinge-teeth. Others seem to belong
to more normal Mesozoic types; but, as the nature of the brachidia
could not easily be seen, it is impossible to make any certain
generic determination of them.

1 W. Waagen mentions that, in the Upper Triassic Kcessen Beds of India,
Dielasma is replaced by the genera Rhextina and Zugmayeria.

Q.J.G.S8. No. 291. s

214 DR. C. T. TRECHMANN ON [vol. ]xxiii,.

No true Spirifers occur in the New Zealand Trias: the spire-
bearing forms are all referable to the genera Spiriferina, Cyrtina,.
Mentz ‘elit, Mentzeliopsis, gen. nov., Metzia, NSpirigera, and
Hectoria, gen. noy. Spir iferina begins i in the Kathiku Beds with.
a small form belonging to the group of Sp. fragilis Schlotheim,
which occurs in the German, Alpine, and Himalayan Muschelkalk.
Both Sp. Jragilis and a large and rather alate form are confined to:
these beds. In the Carnic a series of conspicuous sharply-alate
forms occur, but in the Rheetic beds an extremely long-winged form,
Sp. diomedea, sp. nov., occurs in association with the Spirigerid
genus Hectoria. Bittner expressed his surprise on finding in the’
Himalayan Trias a Spiriferina so alate as Sp. stracheyz Salter,
which he compares in this respect with the Permian Spirifer
alatus. The New Zealand Trias is characterized by some very
much more sharply-alate forms, which represent a morphic equi-
valent of the long-winged Spirifers of the Paleozoic. Some,
however, are more acutely winged than even the most alate of the
true Spirifers.

Various Spirtferine occur, in which the ventral septum and the
dental plate assume the Cyrtiniform arrangement. These include
the Psioidea group of Hector, and some of them resemble certain
forms of the Alpine Rheetic.

A fetzia of the group of R. schwageri Bittner, a rather wide-
spread form in the Alps and Himalayas, occurs in the Carnie.
Other fetzie@ also seem to be present, but my specimens are not.
well enough preserved for description. Jentzelia is intermediate-
in some ways between Jlartinia and Spiriferina. The shell is.
silky and fibrous, and at the same time faintly punctate; a sharp
median septum and dental plates are found in the ventral valve.
I collected two species of Mentzelia high up in the Rhetic at
Kawhia: one with a smooth JJartinia-like shell, and the other
faintly ribbed. They should be searched for at lower horizons and
in other localities in New Zealand.

One of the commonest brachiopods in the Kaihiku Beds is a
Mentzelia-like form having both valves covered with tubular’
spines. It seems to be quite new, and so I have instituted a new
genus for it, and have called it Mlentzeliopsis. It apparently
occurs only in the Kaihiku Beds.

The representatives of the Athyrid or Spirigerid group are
especially interesting. Spzrigera hathikuana, sp. nov., is confined
to the Kaihiku Beds, and belongs to the group of Sp. wrey? already
described by Zittel, but occurring on a Carnie horizon. In the
Carnic a form occurs, which is related, as regards the thickening
of the hinge-region and cardinal process, to Spzrigera oxycolpos
Emmrich, the largest and latest of the Alpine Athyrids confined to:
the Rheetic Koessen Beds.

A still more specialized group, to which I have given the name
Hectoria (subgenus Clavigera of Hector), begins in the Carnic, and
becomes exceedingly common in the Rhetic. They are related to
Spirigera oxycolpos; but they are bisuleate, and have a still more:

part 3] THE TRIAS OF NEW ZEALAND. 215-

exaggerated development of shelly matter in the hinge-area and
cardinal process. The group persists into Jurassic times, the first:
instance known to me of a Spirigerid in the Jurassic.

The appearance in New Zealand, on so low a horizon as the
Carnie, of brachiopods presenting a decidedly Rhzetic aspect, such
as the group of Spirigera oxycolpos (including the new genus
Hectoria), and NSpiriferine of the group of Sp. swesse and
Sp. austriaca and others with the Cyrtinitorm septal structure,
impresses the Upper Triassic Brachiopod fauna of New Zealand
with Rhetic affinities. It suggests that some of the European
Rhetie forms may have originated in the Southern Hemisphere
or round the shores of Gondwanaland. On the other hand, a
Mentzelia very like the European Muschelkalk form JL. mentzeli
occurs high in the Rhetic in New Zealand. The value of the
Brachiopoda for zonal purposes in the New Zealand Trias seems to-
be limited.

It is significant to find in the New Zealand Trias certain phyla
of the Brachiopoda towards the last stages of their existence
developing an excess of shelly matter in the following respects :—

(a) In the Spiriferine, in the form of extremely-alate shells and corre-
spondingly lengthened spiralia.

(b) In the Mentzeliz, as a covering of tubular spines.

(c} In the Spirigere, as an enormously-enlarged cardinal process and a
greatly-thickened hinge-area.

RASTELLIGERA, PsIoIDEA, AND CLAVIGERA.

A few remarks dealing with these subgenera of Hector! are
necessary in discussing the Brachiopoda of the New Zealand Trias.

Rastelligera embraced a group of alate Spiriferine, having a
row of vertical rake-like teeth arranged along the hinge-area. The
comb-tooth structure is certainly very apparent in many of the
New Zealand Spiriferine, but especially so in the very alate form
that I have called Spiriferina diomedea. Since, however, i 1S
visible also in many true Spirifere of the Palwozoic, as well as in
Spiriferina, it cannot be regarded as of generic significance. In
some at least of the specimens that I examined I concluded that
the shell-surface had been partly decomposed and the outer layer
destroyed previous to fossilization. This surface-erosion seems to:
have taken place readily in the coarser sediments. In one specimen
the central part of the area showed the comb-like structure ; while
towards the wings the outer surface remained, and was longitudinally
striate as in an ordinary Spirifer. The structure certainly does
not appear on the alate Spiriferina kathikuana of the Kaihiku
Series, and in consequence Hector concluded that Rastelligera
was absent from those beds; but I am inclined to think that the
greater fineness, or more rapid deposition, of sediment in those
beds prevented the surface-decomposition of the shell.

Psioidea designates, according to Heetor, Spiriferine, varying

! Bibliography, 16.

216 DR. C. T. TRECHMANN ON [vet Gaan;

greatly in width of the hinge-line, in which the dental plates join
the median septum. Zugmayer! describes several such Spiriferine
from the Alpine Rhetic, and includes them in his group of
Dimidiate, separating them from the genus Cyrtina, in which
this septal and dental peculiarity also occurs, apparently on account
of their concave and uncovered delthyrium. The Cyrtiniform
septal arrangement is apparently a phylogerontic feature, and
seems to have arisen independently in several phyla of Spiriferine
Hector’s subgenus includes forms which closely resemble the Alpine
Rhetic Spiriferina suessi and Sp. austriaca, and new forms
which I have named Sp. nelsonensis and Sp. otamitensis. The
early appearance of these forms in the New Zealand Trias is a
remarkable feature.

Clavigera represents a group of specialized bisuleate Spirigerids
the affinities of which are discussed later on. I have considered it
advisable to rename this group, and have called it Hectoria.
Hector’s description was published without any illustrations, and
his subgeneric name closely resembles that of Claviger given to
a group of the Melanias.

HALORELLA ZEALANDICA, sp. nov. (Pl. XXIII, figs. la—3.)

Beak prominent, the hinge-line sloping rapidly away from it on
each side, giving the shell a subtriangular outline. The delthy-
rium is triangular and insunken. In the ventral valve is a broad
median suleus with a flattened floor, on which two (or, in some spe-
cimens, four) small rounded folds occur, and continue from about
a third to half of the distance to the beak. The sulcus is bounded
on each side by a broad rounded fold, which continues about half-
way to the beak, and two similarly rounded, but much shorter,
lateral folds on each side. The dorsal valve has a broad median
depression, but it is rather flattened than sunken, and bears two (or,
in some specimens, three) narrow rounded folds on it, which continue
for only about a third, or rather more, of the length of the shell
from the anterior margin. The median depression is bounded
by two broad, rounded, lateral folds which reach about halfway to
the beak, and there are two more rounded but shorter lateral folds.

Dental plates are well developed in the ventral valve, and in the
dorsal valve there is a sharp median septum which extends from
the beak about halfway to the anterior margin. Growth-ridges
are well marked, but widely spaced.

This species varies somewhat in shape and dimensions, and in the
number of secondary ribs on the median suleus; some specimens
are wider, and have a less prominent beak than others. One
example is 16 mm. long and 15 mm. wide; another is 18 mm. long
and 13 mm. wide; a third is 18 mm. long and 15 mm. wide.

Locality and horizon.—It is common in the Kaihiku
Beds at all localities. I collected many casts and impressions at

1 Bibliography, 52.

part 3] THE TRIAS OF NEW ZEALAND. 217

Caroline Cutting in the Hokonui Hills. It persists into the
Carnie beds, but becomes much scarcer.

Remarks.—I think that this shell should be placed in Bittner’s
group Halorella, although the dorsal median sulcus is rather flat-
tened than sunken. In outline it recalls H. pedata var. coarctata
Bittner of the Alpine Trias, but in that form the ribs continue
from the anterior margin to the beak.

HALORELLA sp. (PI. XXIII, fig. 4.)

A single fragmentary dorsal valve has a very faint median sulcus
aud about twenty very regular ribs, all of about equal height. The
sulci between the ribs are of equal depth. The lateral ribs become
eurved as they approach the anterior lateral margins, and all ribs
extend to the beak region. There is a short median dorsal septum.

Locality and horizon.—Highty-Hight Valley, Nelson. Ap-
parently from the Jlytilus-problematicus Bed. New Zealand
Geological Survey Collection. Carnie.

Remarks.—This Halorella belongs to the group of H. pedata
Bronn and H. amphitoma Bronn. It seems to agree best with
HI. pedata var. multicostata, which has twenty or twenty-four ribs.
These forms occur in the Alps in the Hallstatt and Dachstein Beds.
J. Wanner! records a very similar variety of AH. amphitoma, with
about eighteen ribs, from North-Eastern Serang in the Malay
Archipelago.

DieasMa ef. HrMALAYANA Bittner.
1899. ‘Trias Brach. & Lamellibranch.’ Pal. Ind. ser. 15, vo’. ii', pt. 2, p. 25 &
pl. v, figs. 1-8, 10, 11.

Small forms of rounded or oval outline occur plentifully as
casts in the lower strata of the New Zealand fossiliferous Trias.
The shell bears none or only a very faint plication, and gutta-percha
squeezes show that the growth-lines are closely set and well
marked. The dental plates of the ventral valve and the median
septum of the dorsal valve are well developed.

They are generally of small size, and are not strongly inflated :
one specimen is 11 mm. long and 10 mm. wide. :

Locality and horizon.—This form is plentiful in the Kaihiku
Beds at Caroline Cutting and other localities ; and I found casts of
this or a very similar small Dielasma in the Halobia Beds at
Mount Heslington, but they become very scarce in the Carnic.

Remarks.—This form recalls the Permian D. elongata Schlot-
heim, but I think that it is identical with D. himalayana
Bittner, which occurs in the main complex of the Muschelkalk and
in the beds with Spirtferina stracheyi Salter in the Himalayas.

DIELASMA ZEALANDICA, sp. nov. (Pl. XXIII, fig. 5.)

Shell elongated, the outline tapering gradually towards the beak,
but expanding towards the anterior margin, which is well rounded.

1 Bibliography, 49, p. 187 & pl. vii, fig. 8.

218 DR. C. T. TRECHMANN ON [ vol. lxxiul,

Valves somewhat flattened. The beak is prominent, but receding ;
the foramen is large and rather diagonally situated, having en-
croached on the beak through absorption or wear. The delthyrium
seems to have been partly covered by the dorsal beak. The dorsal
valve bears near its anterior margin a very faint, broad, mesial
fold and lateral sulci. Owing to-the extremely-slight plication,
the junction of the valves is nearly straight. The growth-lines are
well marked on the cast.

Dental plates are well developed in the ventral beak. In the
dorsal valve a strong median septum extends for more than a
third of the length of the shell, and supports a prominent shield-
lke hinge-plate.

Length =46 mm.; width =33 mm.; thickness=16 mm.

Locality and horizon.—Kaihiku Beds, Caroline Cutting,
Hokonui Hills. Two casts were collected, one of them crushed.

Remarks.—This form differs from the numerous small Die-
Jasmas in the Kaihiku Beds, in its very much larger size and more
prominent beak. I could not ascertain either the structure of the
erura, or the nature of the shell. Although it 1s only a cast, its
distinctive characters justify the attribution to it of a specific
name.

Ca@NOTHYRIS sp. (PI. XXIII, fig. 7.)

Shell subpentagonal in outline, rather inflated ; the beak tapering
slowly, fairly prominent, and bent over so that the area and part
of the foramen are hidden by the dorsal beak. The dorsal valve
has a broad and high median fold, bounded on each side by a
broad and shallow suleus, which merges into the rounded surface of
the shell. Near the anterior margin the median fold has a faint
suleus on it.

The internal cast shows that dental plates are well developed, but
apparently in part calloused. There is a slight median septum in
the dorsal valve, but nothing of the loops could be seen.

Length =30 mm.; width = 28 mm.; thickness =17 mm.

Locality and horizon.—A single specimen in my collection
occurred in the Pseudomonotis-richmondiana Beds at Richmond,
near Nelson. Noric. A gutta-percha squeeze of the beak and
dorsal valve was obtained from the mould.

Remarks.—This large plicated Terebratulid is the only fossil
that I ever saw associated with Pseudomonotis richmondiana, and
is the only deeply-plicated Terebratulid that I obtained in the New
Zealand Trias.

‘TEREBRATULA’ PACHYDENTATA, sp. nov.: (Pl. XXIII, fig. 6.)

Shell oval and gently rounded in outline; the valves are some-
what flattened and not inflated, and show no plication. The beak
projects but very slightly above the hinge-area, and the foramen
is very small. The growth-lines are fairly well marked. The shell
is remarkably thickened in the umbonal region of the ventral valve,

‘part 3] THE TRIAS OF NEW ZEALAND. 219

the dental plates being massive and calloused. The hinge-teeth
are large and broad, and become very conspicuous in the crushed
specimens. The dorsal valve appears to have had a large cardinal
process and wide dental sockets. The loops seem fairly long, but
nothing definite of their structure could be seen.

Locality and horizon.—Bed c¢, at Otamita, Hokonui Hills,
where I collected three or four well-preserved specimens with the
shell on. One specimen is 27 mm. long and 28 mm. wide;
another is 21 mm. long and 18 mm. wide.

Remarks.—The shelly thickening of the hinge-region of this
‘hell points to its being some phylogerontic form, but of which
generic stock I could not determine. The shell has a fibrous
structure, and bears dark closely-set punctations.

‘TEREBRATULA cf. HUNGARICA Bittner. (PI. XXIII, fig. 8.)
1890. ‘ Brachiopoden der Alpinen Trias’ p. 278 & pl. xxvi, figs. 2-3.

A single specimen is oval in outline, rather inflated, but not
plicate. The area and beak are rather prominent, and the foramen
is small. The surface is smooth, with occasional regular growth-
furrows. Length=12 mm.; width=11mm.; thickness=6 mm.

Locality and horizon.—Bed c¢, Otamita, Hokonui Hills.
Carnic. One specimen in my collection.

Remarks.—This specimen could not be sacrificed in order to
investigate the internal structure; but in outward appearance it
resembles the above-named species, which occurs at high Triassic
horizons in the Eastern Alps.

SPIRIFERINA FRAGILIS Schlotheim. (Pl. XXIV, figs. 10-12.)
1890. A. Bittner, ‘ Brachiopoden der Alpinen Trias’ p. 29 & pl. xxxv, figs. 2-4

The hinge-line in most examples represents the greatest width
of the shell. In the ventral valve the area is high, wide, and
triangular, flat or slightly concave, and the beak is but slightly
bent over the area. The median sulcus is deep and angular, and is
bounded by more or less angular folds, on each side of which are
three lateral folds, the last one often very small. The area of
the dorsal valve is obscure; the beak is small, and projects but
slightly above the area. The median fold is appreciably higher
and wider than the lateral folds, of which there are three or four on
each side of it, the last one being very small. Concentric growth-
lamellz are prominent, and become foliaceous towards the anterior
margin. Length=16mm.; width =i9 mm.

In another dorsal valve of a slightly-different variety (fig. 12)
the outline contracts very slightly below the hinge-line and then
widens out again, becoming somewhat wider than at the hinge-
line. At the hinge-line the shell is 17 mm. wide, but widens out
to 18 mm. below that, and is 15 mm. long.

Locality and horizon.—This form is confined to the Kaihiku
Beds, in which it occurs commonly in most localities. I collected

220 DR. C. T. TRECHMANN ON [vol. Ixxiu,

a series of casts at Caroline Cutting, from which I made gutta-
percha squeezes.

Remarks.—lIt closely resembles Spiriferina fragilis, except
that the beak seems rather less bent over the area than in the
typical European form. Bittner describes a form called Spiri-
Serina lilangensis Stol. from the Muschelkalk of the Spiti district:
of the Himalayas, and remarks on its similarity to Sp. fragilis ; but
the New Zealand specimens seem to resemble the European rather
than the Himalayan form. Sp. fragilis was first described from
the German Muschelkalk. In the Alps it occurs at Wengen in
Upper Ladinic beds, according to Bittner. Piroutet records it.
from New Caledonia.

SPIRIFERINA KAIHIKUANA, sp. nov. (Pl. XXIV, fig. 15.)

The area is broad, and extends the whole length of the wings.
Some specimens are more sharply alate than others ; ; but in all “of
them the hinge-line represents the greatest width of the shell, and
the margin contracts rapidly in front of the wings.. The ventral
valve has a broad, concave, median, rapidly- widening, dorsal furrow
with about six low rounded folds on each side of it. The dorsal
valve has a broad, rounded, median fold with five (in another
specimen seven) low rounded folds on each side, which gradually
diminish in size. The folds occupy the surface of the shell nearly
to the hinge-area. The growth-lines are rather coarse. Casts show
that the posterior part of the inside of the ventral valve was much
filled in with shelly matter, and that there was a sharp median
septum.

One specimen measures 72 mm. across the wings and 41 mm.
in length; another less alate example is 46 mm. across the wings
and 380 mm. long.

Locality and horizon.—This is the only large and alate
Spiriferina that occurs in the Kaihiku Beds, to which it seems to
be confined. The Geological Survey possesses some very fine speci-
mens, of which, unfortunately, only the internal casts have been
preserved. Hector illustrates one of these casts as Zr tqgonotreta
alata,| the English Permian form. It comes from the Crinoid
Beds at Cowan's Railway Station, Oreti Valley.2. From another
specimen found at Highty- Eight Valley, Nelson, I was able to make
a gutta-percha impression of the exterior of the dorsal valve. I
collected some smaller examples at Caroline Cutting.

Remariks.—This shell occurs in a rather fragmentary condition
in the Kaihiku Beds; but, so far as I can ascertain from the
material, the fragments all represent one species, despite varia-
tion in the length of the wings and in the number of the lateral
folds. It shows some affinity With the small Spiriferina Sragilis
which accompanies it, in the width of the area and in the continua-
tion of the ribs up to the area-margin. The only described form

1 Catal. Ind. & Col. Exhibition (1886) p. 76, fig. 3.

? Prof. P. Marshall and I think that this is the same locality as Caroline
Cutting, the name of the station having apparently been changed since the
early survey was made.

part 3] THE TRIAS OF NEW ZEALAND. 221

with which I can compare it is Spiriferina stracheyi Salter from
the Himalayan Muschelkalk, which Bittner says is rather closely
related to the European Sp. fragilis ; but the form here described
is much larger, and is more strongly ribbed.

SPIRIFERINA GYPAHTUS, sp. nov. (Pl. XXIV, fig. 4.)

Shell extremely alate, the wings towards their apices tapering
rapidly to sharp points. The ventral area is very long, concave,
and narrow, and is faintly striate. The beak of the ventral ie
is very small, and projects but slightly above the hinge-area; it
practically touches that of the dorsal valve, which is broad and
projects slightly above the dorsal area.

The dorsal valve has a broad, median, triangular, rapidly-widen-
ing fold, with a fairly-deep angular sinus on each side of it. The
first lateral folds on each side are lower and rather narrower than
the median one, and on either side of these are three much smaller
and fainter lateral folds which gradually decrease in size. All the
folds continue to the beak. The wings towards the apices are free
from folds. The anterior outline of the shell is gently rounded,
and narrows rapidly towards the wings, which continue very narrow
for some distance, ending in sharp points. The growth-lines are
prominent, irregularly spaced, and rather foliaceous.

Length =22 mm.; width =75 mm.

Locality and horizon.—A very fine cast of the ventral beak
and dorsal valve, from which I made a gutta-percha squeeze, comes
from the slopes of South Peak (Benmore), in the Hokonui Hills,
and belongs to the New Zealand Geological Survey. The horizon
is probably Noric.

SPIRIFERINA ACUTISSIMA, sp. nov. (Pl. XXIV, fig. 3.)

Shell extremely alate; the wings are produced into very acute
points. The hinge-area extends the whole length of the wings, is
very narrow, concave, and faintly striate parallel to the margin.
The ventral beak is ver vy small, and projects but slightly above the
hinge-area; that of the dorsal valve is also small, and scarcely pro-
jects above the dorsal area, and the two almost touch one another.

In the dorsal valve the median fold is high, narrow, and trian-
gular, and has a very faint median sulcus on its anterior portion.
On each side of it are six similar folds gradually decreasing in
size and height, the last being very faint. The folds continue
to the dorsal beak, and are divided by rather deep and angular sulci.
The anterior mar gin is ver ‘Yy narrow in propor tion to 1ihie width of
the shell, the lateral margins narrowing gradually to the wings,
which are considerably pr oduced and end in ver y fine points. The
growth-lines are not very prominent.

Length = 21 mm.; width=83 mm.

Locality and horizon.—The New Zealand Geological Survey
possesses a very fine mould of the ventral beak and dorsal valve in
hard dark greywacke, from which I took a gutta-percha squeeze.

222 DR. C. T. TRECHMANN ON [ vol. Ixxiu,

It comes from the east side of Mount Heslington, south of the
Wairoa Gorge, but there is no other fossil on the piece of rock
to indicate its horizon, which is probably Upper Carnie or Noric.
I collected a rather weathered cast of a smaller dorsal valve in
felspathic sandstone in Bed a, Otamita, Hokonui Hills, which is
probably Lower Noric.

Remarks.—Both this and the last species are remarkable for
the very narrow ventral area, the slight prominence of the ventral
beak, and the fact that the apices of the wings end in acute points.

SPIRIFERINA DIOMEDEA, sp. nov. (PI. XXIV, figs. 1 & 2.)

Shell extremely alate, about five times as wide as it is long, the
wings narrowing gradually to the apices. The area extends the
whole length of the wings:

Fig. 38.—Gutta-percha squeeze of the it is broad and high, and
interior apex of the ventral valve showsthe comb-tooth struc-

of Spiriferina diomedea, sp. nov. ture along its whole length;
Rhetic. South Hillend, Otago. but whether the serrated
structure was exposed in
ee the living shell, or whether
i AY during life it was covered
YN «= with an easily decomposable
SSS layer of shell, I am not

lf {fi} TH // Uh [ii

ZS ye i { | | NX XA “able to say with certainty.
jp i in es The ventral beak is blant,
f f- iS = ASN) \\ + a6: - 5 +

WY Mi me \ wide, and rather prominent;

that of the dorsal valve is
[This shows the sunken pit occupied by the byoad, and projects very
dicl d scle-s d di oa: _ ; Cea

Pe eee eee eee eee ge. LalGLy 4 ONE ia iemenenneee

septum, also the area bearing the 1; Tl Pa fe nn
‘comb-tooth’ structure upon whichthe ‘/!°- 1é ventral Valve
subgenus Rastelligera was founded. } has a rather broad, shallow,

median sulcus, and on each
side three or four lateral sulci, only slightly smaller and no deeper
than the median one. The dorsal valve has a wide and low,
triangular, rapidly-widening fold, which extends to the beak, and
bears a slight median depression towards the anterior margin. On
each side are four narrower rounded folds of equal height, which
gradually decrease in size. The wings are free from folds towards
the apices. The delthyrium is wide, open, and triangular. The
median septum of the ventral valve is sharp but low, and extends
for about three-quarters of the distance to the anterior margin ; it
lies in a well-marked hollowed-out depression which accommodates
the muscle-scars, but these are not strongly marked.

Length = 26 mm.; width=127 mm.

Locality and horizon.—The New Zealand Geological Survey
possesses a cast of a ventral valve in coarse felspathic grit, from
the north-western branch of Taylor’s Creek, in the Hokonui Hills.
This form occurs plentifully in the highest Trias with Hectorva
bisulcata at the southern end cf Roaring Bay, Nugget Point, in

part 3] THE TRIAS OF NEW ZEALAND. 223

a hard pebbly sandstone, which stands out as a stack in the coast-
section; but specimens are very difficult to collect, the rock being
so hard. The Survey, however, possesses a fairly-good specimen
from this locality (Pl. XXIV, fig. 2). Prof. P. Marshall has
recently sent me a piece of felspathic sandstone from South Hillend,
12 miles south of Benmore railway-cutting, on the south side of
the Hokonui Hills, with several casts of this shell, from which I
was able to make gutta-percha squeezes (fig. 1). It seems to be
the same bed as that in the Benmore cutting, and contains casts of
a large Hectoria. Rhetic.

Remarks.—This is the largest and latest, as well as by far the
most alate, of the New Zealand Triassic Spirifering. It differs
from the two previously-described species in its larger size and in
the wings narrowing very gradually to the points. The folds are
lower and more rounded, and decrease gradually in size, the area
also is broader, the ventral beak higher, and it occurs on a higher
horizon than the two previously-described forms, which are of
Carnie and Noric age.

SPIRIFERINA NELSONENSIS, sp. nov. (Pl. XXIV, figs. 6-8.)

Shell alate, valves rather inflated, the anterior margin js gently
rounded in outline. ‘The ventral valve has a broad median sulcus,
which extends to the beak, and is bounded on each side by four
rounded slightly-raised ribs, which decrease gradually in size. The
dorsal valve has a triangular median fold, which increases rapidly
in width, and on each side of it four fainter rounded ribs which
are continued nearly to the beak.

The area of the ventral valve is wide, high, and concave; it is
longitudinally striate, and represents the greatest width of the shell,
the margin of the valves converging rapidly in front of the area.
The delthyrium is triangular, wide, and open, bounded on each
side by dental plates, which converge together inwards and meet
the median septum: this latter is visible at the bottom of the
open delthyrium as a thin plate projecting slightly above the line
of junction of the dental plates. The surface of the dental plates
is faintly furrowed. On both sides of the delthyrium another
slightly-sunken triangular area is separated off, and is ornamented
with faintly -impressed vertical furrows. ‘The dorsai area is narrow,
and a ‘comb-tooth’ structure is seen for a short distance on each
side of the dorsal beak. The growth-lines are fairly well marked.

Length=23 mm.; width=45 mm.

Locality and horizon.—I collected three or four specimens
in the Halobia Beds on the western slope and crest of Mount
Heslington in the Nelson district. The New Zealand Geological
Survey possesses a specimen from the same locality. Carnie.

Remarks.—Zugmayer divides his group of Rheetic ‘ Dimidiate ’
into two ‘form groups’ (Formenkreise): namely, the group of
Spiriferina uncinata and that of Sp. swess?, the latter including
only the single species. The species here described apparently

224 DR. C. T. TRECHMANN ON - [vol. Ixxii,

belongs to the first group, which comprises forms with vertical striz
on the dental plates and on the adjacent areal portion on each side
of them: these, Zugmayer thinks, may have assisted in attaching
a ligament or external muscle. He illustrates three species that:
show this peculiarity : namely, Sp. uncinata, Sp. kessenensis, and
Sp. austriaca ; but they are all non-alate forms with a very high
ventral area.

SPIRIFERINA cf. ausTRTACA Suess. (Pl. XXIV, fig. 5.)
1882. H. Zugmayer, ‘ Untersuchungen iiber Rhatische Brachiopoden’ p. 28 &.
pl. inl, figs. 6a-6 e.

Shell about as long as it is wide. Ventral area high and trian-
gular, shghtly concave, and coarsely striate parallel to the hinge-
margin, which represents very nearly the greatest width of the
shell. The delthyrium is triangular and deeply sunken, the septal.
arrangement is cyrtiniform, and the thin median septum is seen
towards the apex projecting above the floor of the delthyrium.
The ventral beak is bent slightly over the areal region; the dorsal

beak is rounded, rather inflated, and projects slightly above the

hinge-area.

The dorsal valve is semicircular in outline, and has a raised,
rather narrow, median fold, and three or four much fainter lateral
folds, which cover the shell nearly to the hinge-margin. The ventral
valve has a broad and shallow triangular median suleus, which
extends to the apex and is bounded by two raised narrow folds,
on each side of which are two or three much fainter lateral folds.

Length = 38 mm.; width= 38 mm.

Locality and horizon.—The New Zealand Geological Survey
possesses a specimen from Mount Potts, from which the above
description was made. The shell is well preserved; but the del-
thyrium is nearly filled up with rock, and part of the dorsal valve
is concealed. J am not sure whether it comes from the Kaihiku
Series or from the Lower Carnic, but it is probably from the latter.
I have three or four smaller, separated, single dorsal valves
apparently belonging to this species, some of which have a faint
fourth lateral fold. I collected them in low Carnic beds on the
north side of the entrance of the Wairoa Gorge.

temarks.—The attribution of this brachiopod to the above
Alpine species is conjectural, but it evidently belongs to the group
of Sp. uncinata and Sp. austriaca; the former, however, has a
series of vertical strie on the area next to the delthyrium, which is
wanting in the present form and in Sp. austriaca, but is found
in the form last described, Sp. nelsonensis. In general shape it
resembles Spirifertna austriaca, which occurs in the Starhemberg
Beds of the Alpine Rhetic.

Hector! illustrated a drawing of the specimen from Mount
Potts under the title of ‘Spiriferina (cristata ?), the small
English Permian fossil, a very different species: this gave rise to

' Catal. Ind. & Col. Exhibition (1886) p. 76, fig. 6.

part 3] THE TRIAS OF NEW ZEALAND. 225

the idea that the Mount-Potts Beds were of Permian age, an
idea further supported by the supposed occurrence of Glossopteris
in these beds.

SPIRIFERINA OTAMITENSIS, sp. nov. (PI. XXIV, figs. 9a & 90.)

Both valves are about equally convex and slightly inflated. The
hinge-line represents in some examples the greatest, in others
nearly the greatest, width of the shell. The ventral beak projects
but slightly above the hinge-area. The ventral area extends the
whole length of the hinge-line, is moderately high, concave, and
faintly striate parallel to the margin. The delthyrium is open and
sunken, and the arrangement of dental plates and median septum
is cyrtiniform. In one specimen the apex of the ventral valve is
considerably thickened by a deposit of shelly matter.

The anterior and lateral margins are gently rounded, the outline
forming more or less a semicircle. ‘The dorsal valve has a rounded,
gradually-widening, median fold, with four lateral folds on each
side decreasing gradually in size. The median and the first two
lateral folds extend to the beak, but the last two lateral folds
die away before reaching it. ‘The ventral valve has a rounded,
fairly-deep median sulcus, bounded on each side by five rounded
narrow folds gradually decreasing in size, the last two of which
are very faint and do not reach the beak. ‘The growth-lines are
well marked.

Length = 20 mm. ; width = 27 mm.

' Loeality and horizon.—Bed e, Otamita, Hokonui Hills,
with Halobie of the group of AH. zitteli. I collected several
specimens bearing the shell, but they are more or less crushed or
flattened in the shale.

Remarks.—This species belongs to the Sp.-wncinata group
of the Dimidiate, but differs from Sp. nelsonensis and Sp.
ef. austriaca in having a much narrower hinge-area and a less
prominent ventral beak, and also from the former in the absence
of a vertically-sulcate areal portion on each side of the delthyrium.

SPIRIFERINA SUESSI var. AUSTRALIS, nov. (Pl XXIV, figs.
13a-14.)

1882. H. Zugmayer, ‘ Untersuchungen tiber Rhatische Brachiopoden’ p. 29 &

pl. 11, figs. 14-19.

The ventral valve is semipyramidal in shape, and more or less
semicircular in outline. ‘The ventral area is almost vertical,
triangular, wider than it is high, flat or very slightly concave,
and faintly striate parallel to the hinge-area. The ventral beak
scarcely projects above the area; the delthyrium is triangular and
deeply sunken; on each side of it a very narrow triangular area
is marked off and slightly sunken, and is faintly furrowed longi-
tudinally. In casts of the ventral beak the single incision of the
median septum is seen extending forwards for about a third of
the length of the valve.

The surface of the ventral valve bears a deep, anzular, rapidly-

226 DR. C. T. TRECHMANN ON [ vol. lxxiu,

widening sulcus, which extends to the apex and is bounded on
each side by a slight, rounded, raised fold. The dorsal valve has a
strong, raised, roof-like, rapidly-widening, triangular fold, which
extends to the beak and is bounded on both sides by a narrow
sulcus. The growth-lines are faint, but well marked.

Length=18 mm.; width=20 mm.

Locality and horizon.—The crest of Mount Heslington,
south of the Wairoa Gorge, in fine, brown, decomposed greywackes,
with Halobie of the group of Halobia zitelli. I collected
several specimens, both casts and moulds; but it is not a common
form. Carnie.

Remarks.—This species forms the second group of Zugmayer’s
Dimidiatze, in which the dental plates do not reach the back of
the ventral beak, but join the edge of the median septum where
it passes towards the area, forming a triangular sunken trough in
the areal region. This arrangement obtains also in the Paleozoic
genus Cyrtina, from which Zugmayer separates his Dimidiate,
apparently on account of differences in the delthyrium. He gives
a detailed description of Spirzferina suessi, which in the Alps
seems to be confined to the Koessen facies of the Rheetic. The
New Zealand form appears to be slightly different in shape,
the sides meeting the hinge-area at almost a right angle; but
the differences do not seem to warrant a new specific name for
it. A slight difference, however, is the presence on each side of
the delthyrium of a very narrow, triangular, vertically-suleate area,
which Zugmayer says is absent in the Alpine Sp. swessz, but occurs
in Sp. uneinata, 1 regard the present form as a local variety of
Spiriferina suessi.

A drawing which Hector! published under the name of
‘ Psioidea sp.’ appears to represent this species.

SPIRIFERINA (?) CAROLINE, sp. nov. (Pl. XXIII, figs. 19 a—20.)

Ventral valve semi-pyramidal in shape, dorsal valve almost flat.
The hinge-line is straight, and represents the greatest width of the
shell; the hinge-area is flat and vertical. The ventral beak is
conical and blunt, and does not project above the hinge-area.
The delthyrium is conical and apparently open. The hinge-area of
the dorsal valve is narrow; the dorsal beak is broad and blunt,
and projects but very shehtly above the area.

The ventral valve has a faint, shallow, rapidly-widening, median
suleus, which extends from the anterior margin to near the apex,
and on each side two very faint, shallow and broad, lateral sulci.
Otherwise the surface is gently rounded, and the outline of the
anterior margin is nearly semicircular. The dorsal valve, which is
nearly flat, bears a ver y faint, broad, low, median fold bounded by
scarcely per ceptible lateral sulci.

The interior of the ventral valve (fig. 19 «) shows two thick and
strong dental plates, which converge rapidly together and partly

1 Catal. Ind. & Col. Exhibition (1886) p. 78, fig. 1.

part 3] THE TRIAS OF NEW ZEALAND. 227

fuse; they then become thinner and diverge again, the space between
and in front of them bearing the adductor-scars. Immediately
in front of their point of divergence a strong median septum is
developed, which extends beyond the dental plates. The dorsal
valve has a faint cardinal process with dental sockets on each side,
and small, but well-marked, adductor and diductor sears. Ovarian
pittings are well marked in both valves. The shell-structure is
punctate, and the growth-lines become rather foliaceous towards
the anterior margin.

Length=23 mm.; width=40 mm.; height of area of ventral
valve=10 min.

Locality and horizon.—It occurs in the Kaihiku Beds at.
Caroline Cutting, but seems to be scarce. I collected specimens,
from which gutta-percha squeezes of the interior and exterior of
both valves were made. Prof. Marshall possesses a specimen from
the splintery argillites of Mount Potts (where it occurs in associa-
tion with the Kaihiku fauna), which I recognized as the interior
of a ventral valve of this species.

Remarks.—This brachiopod is peculiar as to shape, and as to
form of the dental plates and septum, and I am unable to refer it
definitely either to Spiriferina or to Cyrtina. The smoothness.
of its valves and the height of the hinge-area recall in some ways.
the very abnormal form Cyrtina zitteli Bittner from St. Cassian,
but in that species the area of the ventral valve is enormously
extended. The appearance of the dental plates in the casts at the
back of the ventral beak, however, prevents its union with the
genus OCyrtina as usually defined.

RETZIA SCHWAGERI Bittner. (Pl. XXITI, fig. 21.)

1890. ‘ Brachiopoden der Alpinen Trias’ p. 21 & pl. xxxvi, figs. 1-4.
1899. ‘ Himalayan Trias Brach. & Lamellibranchs’ p. 42 & pl. vii, figs. 1-3;
p. 54 & pl. x, figs. 16-20.

Shell considerably longer than it is wide, beak prominent and
pointed, lateral margins cently rounded, anterior margin rounded.
The dorsal valve has a median rib, which is rather less prominent
than the ribs on each side of it. There are seven rounded lateral
ribs on each side of the median one; the last five of these are
distinctly curved outwards, and all of them extend to the beak.
The ventral valve has a median furrow no deeper than the next
lateral furrows and seven lateral ribs.

Length=14mm.; width=11 mm.

Locality and horizon.—Western slope of Mount Heslington,
Nelson, ih the Halobia Beds, where it is rather scarce.. I have
two or three casts and impressions, from one of which a gutta-
percha squeeze of the outsile of the shell was made. Carnie.

Remarks.—This shell resembles the Himalayan R. schwageri
var. astatica Bittner, but bears rather more numerous lateral ribs.
RR. schwageri is a species of wide vertical distribution, ranging
from the Muschelkalk to the Dachsteinkalk in the Alps. In the
Himalayas it occurs with Halobie of tie group of H. rugosa.

228 DR. C. T. TRECHMANN ON [ vol. lxxiu,

Piroutet records three Alpine species of Retzia from the Trias of
New Caledonia, of which #. aff. swperbescens is the only one that
resembles the present form.

Menrzevia cf. ampia Bittner. (Ph XXIII, fig. 9.)

1890. ‘ Brachiopoden der Alpinen Trias’ p. 165 & pl. xh, figs. 10-11.

Ventral valve inflated, the dorsal rather less so, area triangular,
rather high, less than the width of the shell, the ventral beak
somewhat bent over it. The ventral valve has a broad and
shallow rounded sulcus, which does not continue to the apex.
The dorsal valve bears a rather broad, rounded, triangular fold,
which does not reach the beak and is bordered on both sides by
steep slopes. In the ventral beak there is a sharp median septum
with sharp dental plates on each side of it. The shell-structure
is‘ fibrous, and at the same time faintly punctate.

Length =31 mm.; width =42mm.; thickness = 20 mm.

Locality and horizon.—I collected a single specimen in
pebbly sandstones, with Arcestes ct. rheticus and Hectoria
bisulcata, several hundred feet above the Pseudomonotis-ochotica
Beds, north of Albatross Point, Kawhia. The wings of this speci-
men are damaged, and the ventral beak is shghtly eroded. Rheetic.

Remarks.—This smooth AMentzelia seems to agree closely with
the above-named species, which Bittner thinks may be a variant
of the Muschelkalk form I. mentzeli. In the Alps JZ ampla
occurs at a horizon corresponding to that of the St. Cassian Beds ;
while the typical JZ. mentzeli is predominantly a Muschelkalk form,
but has been found also in the Carnic of Spiti in the Himalayas.

MENTZELIA KAWHIANA, sp. nov. (Pl. XXIII, figs. 10a & 100.)

Shell rather wider than long, the anterior margin gently rounded.
The ventral valve is somewhat swollen and arched, the beak tapering
gradually, the dorsal valve is almost flat, and the margin of the
valves lies nearly in one plane. The area is less than the width of
the shell, and seems to have been rather high. The ventral valve
has a shallow, rounded, rather broad, median sulcus, with about
seven very faint and narrow, lateral, rounded ribs on each side of
it: these do not continue to the beak, and are absent from the
lateral portions of the shell. The dorsal valve bears a very faint,
flattened, triangular, median fold and about seven very faint, narrow
ribs on each side of it which do not reach the beak. The lateral
portions of the shell towards the hinge-area are smooth.

Length=25 inm.; width=31 mm.

Locality and horizon.—lI collected a single specimen not far
from the last-described form in the Avcestes and Hectoria Beds,
in the cliff-section south of Kawhia Harbour. Rhetice. ;

Remarks.—The shell-structure is fibrous and faintly punctate.
This form rather closely resembles JL paleotypus Loretz, from
the Alpine Muschelkalk, but has fewer radial ribs, a weaker dorsal
fold and ventral sulcus, a more prominent beak, and a less inflated

shell.

part 3] ' THE TRIAS OF NEW ZEALAND. 229

MENTzELI0PsIs, gen. nov. (Pl. XXIII, figs. 11-18.)

Shell thin, the growth-lines being visible on the inner surface.
Beak of the ventral valve prominent, arched, and tapering rapidly.
Hinge-line straight and rather shorter than the greatest width of *
the shell. Area triangular, concave, striated parallel to the margin,
with an open triangular delthyrium. The hinge-teeth situated on
each side of the delthyrium are somewhat prominent, and are sup-
ported by two sharp plates. A sharp and prominent median septum
extends for nearly half the length of the ventral valve. The dorsal
valve is flatter than the ventral. Dental sockets are present, and
between them is a short, blunt, cardinal process. An obscure
cardinal area is present in the dorsal valve, and there is a faint
median dorsal septum. Muscular and vascular impressions are
obscure. The outer surface of both valves bears prominent, fairly-
equidistant, more or less foliaceous growth-lamellz, and is covered
with tubular spines measuring up to 3 or 4mm. in length. ~The
‘spines generally occur on the surface between the growth-lamelle,
but occasionally the latter are prolonged into spines. ‘There is a
more or less prominent dorsal median fold and ventral sinus, .and
fainter lateral ridges. Owing to the feeble articulation the valves
are generally found separated.

A specimen which I ground down showed the spiraha directly.
connected with the crural processes, and two discrete jugal processes,
a condition which obtains in the true Spirifers and in Mentzelia.

The following points show that the brachiopod is really a thin-
‘shelled spiny Mentzelia :-—

(a) The outline, area, and sulcation are that of Mentzelia.

(b) There is a strong ventral median septum with sharp dental plates on
each side of it, well seen in every cast of the ventral beak.

(c) The only specimen that I had available to grind down showed that the
junction of spirals and crura was simple, and the juga apparently
discrete.

(d) The shell-structure is fibrous and silky, but on the only specimen’ that
I have which shows any of the test no punctation could be seen;
if present, it is very faint. ©

The founding of a new genus or subgenus for this shell requires
‘some explanation. Mentzelia is generally a_perfectly-smooth
shell, but Bittner mentions the fact that von Schauroth found a
‘specimen of Mentzelia mentzeli in the German Muschelkalk with
a covering of hair-like spines. The New Zealand form, at least
two species of which seem to occur, has the surface of both valves
covered with comparatively long tubular spines. It bears a similar
relation to Mentzelia as Acanthothyris does to Rhynchonella.
I adopt the commoner species JL. spinosa as the genotype.

Lovality and horizon.—It seems to be contined to the
Kaihiku Beds, Ladino-Carnic. ‘The only true Mentzelie that I
found in New Zealand were in the Rhetic. On looking over the
material that I collected at Mount Heslington, in the Nelson
<listrict, 1 find some dorsal valves of a small spiny brachiopod,

Oo .G.S. No. 291. 7.

230 DR. C. T. TRECHMANN ON [ vol. Ixxiui,.

which, though scarcely adequate for a specific description, appear
to represent a dwarfed species of MJentzeliopsis. These occur in.
the Carnie with Halobia zitteli var. zealandica.

MENTZELIOPSIS SPINOSA, sp. nov. (Pl. XXIII, figs. 11-16.)

The shell is slightly wider than it 1s long; the area is rather
concave, less than the greatest width of the shell, and striated
parallel to the hinge-margin. The ventral valve is inflated and
arched ; the beak is prominent, tapers rapidly, and is rather bent.
over the area. The delthyrium is triangular and deeply sunken.
The ventral valve has a feeble, wide, median sulcus and very feeble
lateral dorsal folds.

The dorsal valve is much flatter than the ventral, and has a
broad, rapidly-widening, triangular, slightly-raised fold, on each
side of which are about five very feeble, narrow, lateral folds. The
growth-lines are rather widely spaced and foliaceous, and are some-
times produced into tubular spines. The latter also oceupy the
spaces between the growth-lines, but are not very closely set. They
attain a length of 3 or 4 millimetres.

A ventral valve measures 19 mm. in len eth and 32 mm. in width ;
another 25 mm. and 30 mm.; two dorsal valves are respectively
20 mm. long and 31 mm. aide. and 20 mm. long and 26 mm. wide.

Locality and horizon.—Kaihiku Beds at Caroline Cutting ;
Kaihiku Gorge; Eighty-Eight Valley, in the Nelson district; and.
other localities, where it is common. lLadino-Carnie.

Remarks.—I collected most of my specimens at Caroline
Cutting, and made several gutta-percha squeezes of the exterior
and interior surfaces of both valves.

MENTZELIOPSIS HORRIDA, sp.nov. (Pl. XXIII, figs. 17 & 18.)

Valves rather inflated, both about equally so. Shell shghtly
wider than it is long; the ventral beak is broad, and tapers slowly..
The ventral valve has a broad, shallow, median suleus which reaches.
to the beak, and on each side of it about six rather faint, but
well-marked, rounded, narrow lateral folds, which also reach nearly
to the beak.

The dorsal valve bears a rounded, triangular, rapidly-widening,.
median fold, with a smaller fold passing down the middle of it, and
four or fivé rather faint, lateral, rounded folds, all of which reach
to the beak. The spines are short, and small and closely set.
Growth-ridges are wadely set and well marked, but not foliaceous.

Length = 22 mm. ; w idth = 26 mm.

Locality and ie ae —Kaihiku Beds at Caroline Cutting
and elsewhere, where it seems to be scarce; but I collected ee
from which gutta-percha squeezes of both valves were made.
Ladino-Carnie.

Remarks.—-This form differs from VW. spinosa in having a
broader beak and a more inflated dorsal valve. The ribs are better
marked and reach to the beak, and the spines are more numerous,.
smaller, and more closely set.

-part 3] THE TRIAS OF NEW ZEALAND. 231

SPIRIGERA WREYI Zittel. (Pl. XXV, figs. 6a & 60.)
1864. ‘ Palaontologie von Neu-Seeland’ p. 28 & pl. viii, figs. 3 a-3 d.

Zittel, when he described it, had only casts of this species, which
Hochstetter collected in the Nelson district. I therefore take the
opportunity of describing and illustrating a fine uncrushed testi-
ferous example, which I found in a pebbly felspathic grit on the
western slope of Mount Heslington. It is rather wider than long,
the ventral valve is rather inflated, the dorsal less so. The ventral
beak is comparatively small; tke area is narrow and faintly striate
parallel to the hinge-margin; the delthyrium is triangular and deeply
sunken, and only slightly hidden by the dorsal beak. The apex
is perforated by a pedicular foramen of moderate size. The ventral

valve has a broad, shallow, median sulcus which dies away about
halfway to the beak, and two faint lateral sulci which only appear
near the anterior lateral margins. The dorsal valve bears near its
anterior margin a broad median fold, which is bordered by steep
slopes. It measures 28 mm. in length, 31 mm. in width, and
16 mim. in thickness. The growth-lines are well marked.

Locality and horizon.—This is a common Carnic fossil in
New Zealand: it occurs at Mount Heslington and in the Wairoa
Gorge; in the Hokonui Hills; at Nugget Point and other places.
in the South Island. It¢ is also reported to occur in New Caledonia.

Remarks.—Zittel mentions the large cardinal process, and
Bittner remarks upon the resemblance of this shell to the Alpine
Rheetie Spirigera oxycolpos.

I have employed the generic name Spirigera (A. dOrbigny,
1847) in preference to Athyris (McCoy, 1844) for the Triassic
forms of this group, in conformity with the writings of Zittel,
Bittner, Diener, and others, by whom it is used so largely.
The name Spzrigera seems to be coming into use to designate the .
Mesozoic Athyrids. :

SPIRIGERA KAIHIKUANA, sp. nov. (Pl. XXV, fig. 5.)

Shell rather inflated, the ventral valve slightly more than the.
dorsal. Outline elongate-oval or subtriangular, often widening
out towards the anterior margin, which is gently rounded. The
ventral beak is prominent, and tapers gradually. The delthyrial
cavity is more or less entirely concealed by the dorsal beak. The
foramen was wide and remained open during life, as the casts are
always attached to the interior of the cavity by rock which filled
up the foraminal passage: this, in some examples, is extended
forward, and encroaches on the delthyrium.

There is a faint broad fold on the anterior part of the dorsal
valve, and a very faint corresponding median depression on the
ventral valve: consequently, the junction of the valves lies almost
in one plane. The ventral apical region is much thickened at the
sides with shelly material, but a passage for the pedicle-muscle
always remains.

at 2

232 DR. C. T. TRECHMANN ON [ vol. lxxiu,

One specimen measures 41 mm. in length and 31mm. in width;
another, of more triangular oie, is 46 mm. long and 52 mm.
wide.

Locality and horizon.—It is confined to the Kaihiku Beds,
and casts are very common at Caroline Cutting, Kaihiku Gorge,
and other localities. I have a few specimens with the shell
preserved, as also a large number of casts. Ladino-Carnic.

Remarks.—This species belongs to the group of Spzrigera wrey?,
but is larger, has a more oval or elongate outline, the delthyrial
region is more hidden by the dorsal beak, the pedicle- passage
remained wide and open, ‘the fold and sinus are much feebler,
and the shell-structure is more coarsely; fibrous. It occurs on a
lower horizon than Sp. wreyz, which is a Carnie fossil.

SPIRIGERA MANZAVINIOIDES, sp. nov. (PI. XXV, figs. 7a & 76.)

Shell wider than long; valves only slightly convex near the
beaks, the ventral rather more so than the dorsal, becoming flat-
tened towards the margins. Near the anterior margin there is a
broad but feeble ventral sulcus, and a low and broad rounded —
dorsal ridge bounded by wide, feebly-marked, lateral sulci. The
area is small, and less than the width of the shell; the beak is very
small and pointed, and projects but very slightly over the hinge-
line. The pedicle-passage is minute. The growth-interruptions
are prominent, foliaceous, irregular, and widely spaced, and the
interspaces are marked with very faint, regular, parallel, concentric
strie. The shell-structure is coarsely fibrous, the fibres directed
towards the median line. A typical, somewhat flattened, specimen
is 80 mm. long and 40 mm. wide.

The internal structure is as follows: it has a thickened ventral
hinge-region and a large cardinal process, beneath which a cavity
projects backwards into the beak region, and is divided by a short,
blunt, median septum. The end of the cardinal process carries a
triangular depression, and there are prominent ventral hinge-teeth
supported by plates.

Locality and horizon.—lI collected six or seven specimens
in dark shales along with Halobia zitteli var. zealandica in Bed e,
Otamita, Hokonui ‘Hills. They have the shell preserved, but are
somewhat flattened or laterally distorted. Carnie.

Remarks.—This shell belongs to the group of Spirigera
oxycolpos Emmrich, of the Rhetic Kcoessen Beds, the latest and
largest of the European Spirigerids; but it differs in being much
flatter, whereas the full-grown Sp. oa ry colpos is a swollen and
rounded shell. It comes very near in shape and outline to
Sp. manzavinii Bittner! of the Upper Trias of Balia in Asia
Minor, a form which (as Bittner remarks) bears comparison with
the New Zealand species Sp. wreyt. In Sp. manzaviniz, however,
the foramen is large, whereas in the present form it is quite minute.

1 Bibliography, 6, xli, p. 107 & pl. i, figs. 9-11.

part 3] THE TRIAS OF NEW ZEALAND. 233:

Spirigera eurycolpos Bittner,! of the Alpine Dachsteinkalk, also
belongs to this group, but differs from the present form in shell-
outline and other details. The internal structure is essentially
similar to that of Sp. oxycolpos, which Zugmayer has described in
detail, a structure which exists in a more exaggerated form in
the group next to be described.

I have very strong reasons to think that the New Zealand Trias,
if thoroughly searched, would yield more and different forms of
the group of Spirigere, to which Sp. wreyt, Sp. kathikuana, and
Sp. manzavinioides belong. The New Zealand Geological Survey
possesses another such form, and I have fragments of others; but
the rather doubtful locality-record of the former, as also the poor
condition of my material, makes it unadvisable to found further

new species at present.

Hectoria, gen. nov. (Pl. XXV, figs, 1 a4 0.)

‘The hinge-line slopes very slightly away from the beaks, and
represents the greatest, or nearly the greatest, width of the shell.
) The ventral area extends for

_ Fig. 4.—Specimen of Hectoria sp. nearly the whole length of
From Carnie shales at Ota- the hinge-line: it is narrow,
mita, partly ground down. but conspicuous, and has faint
parallel striations; the area
of the dorsal valve is nearly
obsolete. The ventral beak
projects but very slightly
above the hinge-line; the
dorsal beak is rather less pro-
minent. The valves are almost
equally convex; the ventral
sometimes slightly more so
than the dorsal. Both valves.
have a more or less pronoun-
ced, median, rapidly-widening
a=Dental sockets. sinus, bounded on each side

b =Cardinal process of the dorsal valve. ‘ :
Gah: recaryine of the primary lamella, PY rounded lateral folds which
diverge from the beak and

d=The medio-laterally directed spiralia.
pass to the anterior margin,

where they meet similar folds of the opposite valve. The june-
tion of the valves lies almost in one plane, or is very slightly
sinuous. The shell-structure is silky and fibrous, the fibres being
mostly directed towards the median line. In a cast that I collected
in Carnic beds near Gore, in the Hokonui district, the. beak has.
been pierced by a narrow and long arched tubular foramen, but
in others, and especially in the larger and more fully erown
specimens, the foramen is filled up and obliterated by the shelly
thickening of the beak. The delthyrium is triangular and sunken,
and in the larger specimens at least is closed.

1 Bibliography, 4, p. 273 & pl. xxix, figs. 7-13.

234 DR. C. T. TRECHMANN ON [vol. Ixxin,

The following account of the internal structure is based chiefly
on large specimens of Hectoria tumida, from the Rhetic of
Benmore Cutting, where fine moulds and casts occur, from which I
obtained gutta-percha impressions. The interior of the ventral
valve is considerably thickened posteriorly by deposition of
shelly matter; the hinge-teeth are prominent, are supported by
short dental plates, and there is a short median septum.

In the dorsal valve the hinge-region is still more thickened ;
the cardinal process is very large and prominent, and consists of a
blunt tongue-shaped mass of shell, which projects backwards
beneath the delthyrial region of the ventral valve. The cardinal
process has a shallow depression on its surface. In front of the
cardinal process a deepened cavity projects backwards beneath it,

Fig. 5.—Gutta-percha squeezes of interior of apices of valves of
Hectoria tumida, gen. et sp. nov. (Natural size.) Rhetie.
Benmore Cutting. |

a=Dorsal valve, showing the large tongue-like cardinal process with the
hollowed-out space in front of and below it divided by a median septum.
Slight dental sockets occur on each side of the cardinal process.

b=Ventral valve, showing the concave slightly-striated area, the small
hinge-teeth and plates supporting them, and the small median septum.

and is divided by a rather high, blunt, median septum which
separates the two adductor-scars. On each side of the cardinal
process is a fairly-deep dental socket. The ovarian pittings,
vascular impressions, and muscle-scars are well marked in both
valves, the diductor-scars of the ventral valve being flabellate.
The spiral cones are laterally directed. The arrangement of the
juga and junction of the spiralia with the crura could not easily be
seen; but, on grinding down a specimen from the Carnic shales
at Obie I concluded that it was similar to that which obtains
in other Spirigerids.

a

part 3] THE TRIAS OF NEW ZEALAND. 235

This genus comprises a well-defined group of specialized bi-
‘suleate Spirigerids, which shows close relationship to Sp. owycolpos
of the Alpine Rheetic in the structure of the cardinal process and
the deepened pit beneath it. They differ, however, in features
sufficiently marked to justify their attribution to a new genus or
‘subgenus, such as the equal convexity and equal median sulcation
in both valves, the greater internal posterior thickening of the
valves; and the relatively-larger size of the cardinal process.

Locality and horizon.—Two species appear to occur in the
Trias, and one in the Jurassic, of New Zealand. They are rather
‘scarce in the Carnic of the Hokonui district; but they occur in
great abundance in some beds of Rheetic age, and a single rather
dwarfed form survives into the Jurassic.

Remarks.—Hector proposed the generic name Clavigera for
this group, in a paper read before the Wellington . Philosophical
Society in 1878. An abstract of this paper was published the
following year, but it never appeared in full. Some plates which
he caused to be printed about that time have recently been issued
with a paleontological bulletin already mentioned. Pl. 1 is
occupied by illustrations of the genus Clavigera. Some years ago
Mr. McKay collated these plates, and labelled the species so far
as he could from memory: he gave the species on pl. i as follows:
Clavigera bisulcata, Cl. cunerformis, Cl. gracilis, Cl. tumida,
and Cl. ‘sp.innom.’ I have adopted the specific names bswlcata,
tumida, and cunetformis for the forms for which Hector appa-
rently intended them—the last name referring to the Jurassic
shell. Olavigera gracilis is a cast from Benmore Cutting,
apparently identical with C7. tuwmzda. Hector gave drawings of
Cl. cuneiformis and of a cast of Ol. tumida, but without any
‘specific names, in a work issued in 1886.2? For reasons already
stated, I considered it advisable to discard Hector’s name Clavigera
and to institute that of Hectoria instead.

HECTORIA BISULCATA, sp. nov. (Pl. XXV, figs. la & 18.)

Shell rather wider than long, moderately inflated, the valves
almost equally convex. The hinge-line is nearly straight, and
represents the greatest width of the shell. The area is narrow and
faintly striate parallel to the margin, and the ventral beak projects
slightly above the area. The delthyrium is triangular and in-
sunken. The growth-lines show that the outline of the young
shell was rather strongly alate; but towards maturity it becomes
less so, and is more or less produced anteriorly. The outline main-
tains the same width at the sides for some distance from the
hinge-line, and then narrows to the anterior margin, which is gently
rounded. In both valves two raised rounded ridges diverge from
the beaks, and proceed towards the anterior margin meeting the
similar ridges of the opposite valve. They enclose a shallow,

1 Bibliography, 47.
2 Catal. Ind. & Col. Exhib. (1886) p. 72, figs. 2 & 3.

236 DR. C. T. TRECHMANN ON — [vol. lx 1

rapidly-widening, triangular sulcus; but towards the anterior
margin both ridges and sulcus become weaker, and merge into the
rounded surface of the shell. The junction of the shell is but
slightly sinuous.

The type-specimen is 51 mm. long, 63 mm. wide, and the two.
valves are 25 mm. deep.

Locality and horizon.—Casts apparently of this species.
occur in Carnic and Noric strata at Otamita, Hokonui Hills. At.
Nugget Point it is extremely abundant, together with Spirzferima
FRB Ae at the southern end of Roaring Bay, in a bed of very
hard pebbly sandstone of Rhetic age, which here closes the
Triassic sequence. It is less common at Kawhia, where it occurs.
sporadically through a very thick series of grey sandy Rhetic
deposits overlying “the Norie Pseudomonotis shales. I obtained
one very fine example there and several less perfect ones, also
several specimens at Nugget Point. The New Zealand Geological
Survey possesses a specimen from blue sandstones and chert at
the main branch of Taylor’s Creek, on the south side of the
Hokonui Hills, in beds apparently of Rheetic age.

HECTORIA TUMIDA, sp. nov. (PI. XXV, fig. 2.)

Shell very slightly wider than long; valves inflated, the ventral
often rather more so than the dorsal. The hinge-line slopes gently
from the beaks, and represents rather less than the greatest width
of the shell; the area is concave, and striated parallel to the margin.
The ventral beak is broad, and projects slightly above the hinge-
area. The delthyrium is triangular and insunken, and elosed
internally by shelly matter; it is partly concealed by the dorsal
beak. The outline is gently rounded at the sides, but is some-
what prolonged and rounded anteriorly. Rounded ridges diverge
in both valves from the beak, and extend to the anterior lateral
margins ; but in this species they become somewhat indistinct, and
tend to merge into the swollen and rounded outline of the shell,.
and on the dorsal valve they form a more or less flattened or gently
rounded, raised, median, triangular fold rather than a suleus. The
growth-lines are well marked doves the anterior margin.

A typical specimen is 60 mm. long and 63 mm. wide.

Locality and horizon.—Benmore Cutting, on the south
side of the Hokonui Hills, in a coarse, decomposed, pebbly,
felspathic sandstone. Many casts of this large shell occur here.
I collected and brought home several internal casts, and a mould
from which I was able to obtain a cutta-percha impr ession of the
ventral beak and area and dorsal va ae: but the surface of the shell
is damaged and pitted by the quartz-grains in the rock. The
description of the internal structure of the hinge-region given in
the diagnosis of the genus is based on moulds of the separated
ventral and dorsal valves, which I obtained in this locality and
brought home with me. Rhetic.

Remarks.—This is a distinctive form, and seems to occur in
high Rhetic beds. It differs from A. biswlcata in its larger size

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SISCONAG “TA

part 3] THE TRIAS OF NEW ZEALAND. 237

and more inflated shell, its relatively narrower hinge-line, and
much less clearly-marked foids and sulcus. In its general rounded

outline and swollen surface it somewhat recalls full-grown speci-

mens of the Alpine Sp7rigera oxycolpos.

HECTORIA CUNEIFORMIS, sp. nov. (Pl XXV, figs. 4a & 40.)

Valves about equally convex, compressed, and but slightly
inflated. The junction of the valves is nearly straight. The
hinge-margin slopes very gently away from the beak, and ‘represents

the eveatest width of ihe shell, The ventral beak is very small,

and projects but slightly above the hinge-margin ; the ventral area
is extremely narrow. In front of the hinge- line the lateral margins.
converge together rather rapidly, and the anterior mar ein 1s strongly
hollowed out between the ridges. The median sulcus and the
rounded ridges on each side of it are well marked in both valves ;
they continue in full strength from the beak to the anterior
margin. Ridges of growth are rounded and fairly prominent, and
the structure of the shell is coarsely fibrous.

The type-specimen, from Taylor’s Creek, is 25 mm. long, 87 mm.
wide, and 11 mm. thick.

Locality and horizon.—A fine specimen in the New Zealand
Geological Survey Collection was obtained in the lowest part of
the lower Ammonite Bed at Taylor’s Creek, in the Hokonui Hills.
Prof. P. Marshall lent me a fragment of a valve that he collected
at Totara Point, in the harbour of Kawhia. Iam at present un-
certain about the exact horizon of the Jurassic at Totara Point;
but I think, from an examination of the associated fossils, that it
is Bajocian.

Remarks.—This form is smaller than H. biswlcata, the sulcus
and ridges are better marked, and the beaks relatively smaller.
It is a dwarfed Jurassic survival of an essentially Upper Triassic

group.

VII. RELATION oF THE NEw ZEALAND TRIAS TO THAT OF
New CALEDONIA AND THE MALAy ARCHIPELAGO.

New Caledonia lies on the north-westerly continuation of the
Australian festoon or submarine ridge which connects the Auckland
Peninsula with Norfolk Island and the Malay region.

On the south-western side of New Caledonia the Trias shows a
close agreement with that-of New Zealand. The points of simi-
larity and difference seem to be as follows :—

(a) At the base occurs a thick detrital series devoid of
fossils. Piroutet supposes this to represent probably the
Permian and the lower divisions of the Trias, and it evi-
dently corresponds with the Kaihiku Series below the lowest
fossiliferous horizon in New Zealand.

(b) Above this comes a series of shales, greywackes, tufts,
andesitic breccias, and corglomerates, which represent the

VI. Syvopsts or tHe Dryistons anv Mossmms or tHe New Zraranp Trras.

*

—-

=

Ruxrie.

Spiriferina diomedea and
Hectoria tumida.

CEPITALOPODA,

j Outi gue cs Sp.

mesodiscum Hiner
itus cf. spivolobus Dittma,
Arvestes ©
Cladiscites sp,
| Pinicoceras sp
| Discophyllites
Lilacoceras sp-

Mojsisovies

GASTEROPODA.

Patella (2) nelsonensis, sp). nov. -.-

Plewrotomaria (Sisenna) hectori, sp. nov. .

Pleurotomaria hokonwiensis, sp. nov.
Coronaria spectabilis, sp. ov.
Bowrquetia (2) avata, sp. nov.
Trochus (Lectus 2) marshalli, Sp. noy.

ScapHoropa.

IDL AAA STB icee ores s-neoo eh Lork ye pe oa 53594

Bs
j PrERopopa (?).

GOmUTGIIG SPs <.--02--- ne sn een eee

LAMELLIBRANCHIATA.

Cardiomorpha (2) miggetensis, sp. nov.
Paleoneilo ofamitensis, sp. n0y.
Paleoneilo ct. preacuta Klipstein
Leila semicrenulata, sp. nov.
| Macrodon ct. ewrionii Bittne:
| Psewdomonotis ochotica elle
j Do. do, varieties
Pseudomonotis richmondiana Zit
Do. do. varieties
Monotis salinaria Broun .... aoe
Do. do. var. inter media,
Do. do. var. hemispheric
Daonella iutica Bittner

Halobia zitteli vay. zealandica, nov. .........

Hualobia hochstetteri Mojsi
Halobia ck. aushriaca Mojs
Halobia spp.
Mytilus (2) problematicus
Mytilus (2) mirabilis, sp. nov.
Hokonuia limeformis. gen, et sp. nov.
Hokonuwia votundata, s). nov.
Hokonuia spp.
Pinna sp. .
Peeten sp.
Limatula cf. p
Cassianella sp-
| Anodontophora angulata, sp. noy
' Anodontophora ovalis, sp. nov.

Anodontophora edmondiiformis, sp.
Megalodon qlobulavis, sp.nov. -.-

ileri Bittner

Pseudoplacunopsis placentoides, sp. nov. a

| AMyophoria nuggetensis, sp. nov.
Myophoria otamitensis, sp. nov.

| Myophoria heslingtonensis, sp. noy-
| Paleocardita quadrata, sp. nov.

| Pleurophorus zealandicus, sp. nov.
Anisocardia (2) parvula, sp. noy-

| Bracwroropa.

| Halorella zealandicd, sp. nov.

_ Halorella sp.

|
{
|
|
|

UPPER TRIAS.

MIDDLE
DRIAS ?

| Dielasma cf. hii
| Dielasma zealandica, sp. nov.
| Cenothyris (@) sp..
* Derebratula” “pachydentata, sp. Pp. nov.
‘Derebratula’ cf. hungarica Bittner

Sa Sr oa Schlotheim ....

Spi a a otamitensis, sp. nov.
Spiriferina suessi var. australis, nov.
Spiriferina (2) caroline, sp. nov.

| Retzia schwageri Vitter -

| Mentzelia cf. ampla Vittner

j Mentzelia kawhiana, sp. nov.
| Mentzeliopsis spinosa, gen. et sp. nov.
| Mentzeliopsis horvida, sp. nov.
Spirigera wreyi Zittel
1S igera kaihikuana, sp. nov.

pirigera manzavinioides, sp. nov.
| Hectoria bisuleata, gen
| Hectoria twnida,

et sp. nov.

—— eee —_—
Ovarinn | Wargoa. Orrar, Karniku,|
Fs Co~—)
Lapino- \
Norte. Carnic, Canrntc.
—SN5 — OS OOo oOo {
= g P | Affinities and Occurrence
s S = : a outside New Zealand.
Ss a t | As pS .
likes & x 3 Ens
Sas bes 8 g as
£132 Seg |] 8 = BS
2 | 3s .|/ 88/0 @ 33
S | §§ a) agg) c = 36 =
§ | 3s S| S82] § Soa)
So UStee 0S aS =
Ss [Ss s/ 3585/5 = 35
-2 | 28 © Su |S 5 ae
os Se Si] suo} = = Bi)
gq |e ais 5 5 a
+
+ on me [cen . ae
. ar Brae ees ae Ss
| sas a oa Pade
F ES BG Alps (Ihsetie). 1
all Soo+ fp i
+) P P
Se ee {+ ? oe Himalayas, New Caledonia (?).
+ i
| |
? : + |
m5 ' era faeee H |
3 | +
Z Pet lie ee |
: i + |
| |
. |
| .
Fa
|
+ + + |
| | A |
| |
: sed TS Hd |
| eo Pacn aves |
as | 6g WE ea }
ee jisaces erase | j
3 5 oS i el bas a f | si F Himalayas. Malay Islands, Avetic ;
+ rer incre Fe = cea) mec Siberia, Japan, etc. (Noric).
| x sea en x : a } New Caledonia (SOW:
ay oI oe 1 Alps, Pairs, Ataeotane Himalayas,
| 5 | Ba J Malay Islands (Carnic and Noric).
| | + Himalayas, Malay Islands.
| | {| Closely related form in Spitsbergen,
a Bear Island, and New Caledonia.
fe New Caledonia (?).
H + | Alps, New Caledonia (?).
| oP 1
ce + New Caledonia.
a +
| + i
| + + i
+ + } I
| 2 2
teal
] + Alps.
+
ue
au Rem ON aes BS Allied to Himalayan forms.
me Spoil ae
+
| on +
5 3
: + | |
By ret ae | Settee nce Allied to forms in St. Cassian Beds.
pea (eames
eee | aD
| i
| i
Related to the Alpine form H. HELENE
Himalayas. as
} foceihemet
. 3 Be
} | + { Huvopean Muschelkalk, Alps, Hima-
} } f layas, New Caledonia
Related to Alpine Rhiwetic form.
Related to Alpine Rheetic form.
Alps, Himalayas.
Related to Alpine and Himalayan
Muschelkalk and Carnie forms.
New Caledonia (?).
Allied to form in the Trias of Asia Min

Related ORR PTLD of
Sato Bu

|
|
|
|

238 DR. C. T. TRECHMANN ON [ vol. lxxin,

Ladinic, Carnic, and Noric horizons, and pass conformably
upwards into the Lias.

(c) Piroutet regards the lowest fossiliferous beds, which contain
Halobia zitteli, as of Upper Ladinic age. I ean find no
mention of the occurrence of any equivalent in New
Caledonia of the Kaihiku fossiliferous beds with Daonella
tndica, which form a lower horizon than the Halobia-
zittelt Bedin New Zealand. Spiriferina fragilis, however,
figures in Piroutet’s list of fossils, and so some members
or survivals of the Muschelkalk fauna seem to be present.
I prefer to regard Halobia zitteli as a Carnie fossil and
the bed below it as Ladino-Carnice.

(d) The Carnic Series in New Caledonia has the beds with
Mytilus problematicus as its base, and includes among
its fossils Halobia superba, H. austriaca, several indeter-
minate species of Arcestes, Discophyllites, Spirigera,
Spiriferina, ete.

(e) The Noric attains a thickness of at least 4920 feet, and
contains Pseudomonotis richmondiana in great abundance.
There is no record yet of Ps. ochotica or Monotis salinaria
in New Caledonia.

(f) No mention is made of any definite Rhetic fauna, nor can
any reference to the bisulcate Spirigerids of the Hectoria
eroup be found. Piroutet, however, records fossils which
present affinities with those of the Alpine Dachstein in his
lists.

(gq) The Mytilus-problematicus Beds are said to be transgres-
sive, and to begin in the coastal region with a conspicuous
conglomerate, which rests upon the trachytice tuffs of the
middle portion of the underlying series. The Pseudo-
monotis Beds are again transgressive, and rest upon beds
increasingly older as “they extend westwards.

The presence in New Zealand of thick and coarse conglomerates
at various horizons, together with the local absence of the Noric
Pseudomonotis Beds, points to local transgression and retrogression.
This is notably the case at Nugget Point, where a thick coarse
conglomerate appears rather low in the Carnic, and where the
Pseudomonotis Beds are entirely wanting. The Trias in New
Zealand, however, is too much disturbed, and the outcrops are too
discontinuous to enable one to make definite assertions as to the
extent or direction of such transgressions.

The Triassic deposits in the eastern part of the Malay Archi-
pelago belong, with one exception, to the Upper Trias. The ex-
ception is that of a piece of rock containing a Ceratitic ammonite
of the genus Dinarites, which was’ ejected by a mud-voleano on the
southern coast of Timor. Upper Trias has been found on seven
distinct islands spread over the whole East Indian Archipelago.
The beds discovered by Volz in Sumatra, and those in Borneo
described by Vogel, are also of Upper Triassic age.

part 3] THE TRIAS OF NEW ZEALAND. 239

The faunal transgression which began over a wide

area

Midd

of the Malay Archipelago at the end of the
le Trias, or the beginning of the Upper Trias,

extended also to the regions now occupied by New Cale-
donia and New Zealand.

(1) E.
(2) EL
(3) A.
(4) A.
(5) A.
(6) A.

@)rG.

(8) J.

(9) S.
(10) C.
(11) ©.
(12) C.
Mls) 2
(14) E.
(15) J.
(16) J.
tis)
(19) E.
(20) G.
(21) P.
(22) P.
(23) P.

(24) P,
(25) P.

(26) A.
(27) A.
(28) A.
(29) A.
(30) A.

VIII. BrprioGRapny.

A. N. Arper.— The Earlier Mesozoic Floras of New Zealand* Proc. Camb.
Phil. Soc. vol. xvii, pt. i, pp. 122-31. 1913.

A. N. ArBer.—‘ Preliminary Note on the Fossil Plants of the Mount-Potts
Beds, New Zealand’ Proc. Roy. Soc. ser. B, vol. lxxxvi, pp. 344-47. 1918.
Brrrner.— Lamellibranchiaten der Alpinen Trias’ Abhandl. k.-k. Geol.
Reichsanst. vol. xviii. 1895.

BITTNER.—‘ Brachiopoden der Alpinen Trias’ Abhandl. k.-k. Geol. Reichs-
anst. vol. xiv. 1890.

BittNER.—‘ Himalayan Fossils: Trias Brachiopods & Lamellibranchs’
Pal. Ind. ser. 15, vol. ii1, pt. 2. 1899.

Brirrner.—‘ Triaspetrefakten von Balia in Kleinasien’ Jahrb. k.-k. Geol.
Reichsanst. vol. xli, pp. 97-116 ; vol. xlu, pp. 77-89; vol. xlv, pp. 250-54.
1891-95.

Baeum.— Fossilien der oberen Trias von der Stidinsel Neuseelands ’
Centralb. f. Min. pp. 632-36. 1910.

Baum.— Ueber die Obertriadische Fauna der Bareninsel’ Kungl. Svensk.
Vetenskaps-Akad. Handl. vol. xxxvu, No. 3, pp. 3-76. 1903.

H. Cox.— Report on the Geology of the Hokonui Ranges’ N.Z. Geol. Surv.
Rep. Geol. Expl. pp. 25-48. 1878.

DrenER.—‘ Ladinic, Carnic, & Noric Faune of Spiti’ Pal. Ind. ser. 15,
vol. v, No. 3. 1908.

Drener.— Fauna of the Himalayan Muschelkalk’ Pal. Ind. ser. 15, vol. v,
No.2. 1907.

Dirner.— Fauna of the Tropites Limestone of Byans’ Pal. Ind. ser. 15,
vol. v, Ne. 1. 1906.

Frecu.— Lethea Geognostica’ pt. 2, vol.i. 1908.

Havue.—‘ Traité de Géologie: IT. Les Périodes Géologiques’ pp. 848-928.

Hector.— Progress Report’ N.Z. Geol. Surv. Rep. Geol. Expl. pp. i-xu.
1878.

Hectror.—Trans. N.Z. Inst. vol. x1, pp. 537-39. 1879.

von HocustretTer.—‘ Neu-Seeland’ Stuttgart, 1863. ,
Koxren.— Gastropoden der Trias um Hallstatt’ Abhandl. k.-k. Geol.
Reichsanst. vol. xvii, pt. 4, pp. 1-112. 1897.

KoxEn.—‘ Beitrage zur Kenutniss des Stiddeutschen Muschelkalkes’ Ab-
handl. z. Geol. Specialkarte v. Elsass-Lothringen, n.s. pt. 2, pp.1-49. 1898.

Linpstrom.—‘ Trias & Juraférsteningar fran Spetsbergen’ Kongl. Svenska
Vetenskaps.-Akad. Handl. vol. vi, No. 6, pp. 1-20. 1865.

MarsHati. New Zealand & Adjacent Islands’ Handbuch der Regionalen
Geologie, pt. 5, vol. vii, sect. 1. 1911.

Marswatt, J. M. Bewn, & E. pe C. Crarnxke.—‘ Geology of the Dun Moun-
tain Subdivision, Nelson’ N.Z. Geol. Surv. Bulletin 12, n.s. 1911.

Marsuatu.— Boulders in Triassic Conglomerate, Nelson’ Trans. N.Z. Inst.
vol. xxxvi. pp. 467-71. 1903.

MarsHaLt.— Geology of New Zealand’ 1912.

MarsyHatit. Some New Zealand Fossil Cephalopods’ Trans. N.Z. Inst.
vol. xli, pp. 143-44. 1908.

McKay.—‘ Report on the Wairoa & Dun Mountain’ N.Z. Geol. Surv.
Rep. Geol. Expl. pp. 119-59. 1878.

McKay.— Notes on the Fossils obtained in the Hokonui District’ N.Z.
Geol. Surv. Rep. Geol. Expl. pp. 49-90. 1878.

McKay.— Report on a Collection of Fossils from Mount Potts’ N.Z.
Geol. Surv. Rep. Geol. Expl. pp. 91-109. 1878.

McKay.—‘ The Older Sedimentary Rocks of Ashley & Amuri Counties’
N.Z. Geol. Surv. Rep. Geol. Expl. pp. 83-107. 1881.

MckKay.—‘ Geology of the Kawhia District’ N.Z. Geol. Surv. Rep. Geol.
Expl. (1883) pp. 140-48. 1884.

240 DR. C. T. TRECHMANN ON [ vol. lxxiii,.

(81) A. McKay.—‘ District between the Wairau & Motueka Valleys’ N.Z. Geol..
Surv. Rep. Geol. Expl. pp. 97-121. 1879.

(32) E. von Mosstsovics.— Cephalopoden der Hallstatter Kalke: das Gebirge um
Hallstatt’ Abhandl. k.-k. Geol. Reichsanst. vol. i. Suppl. 1902.

(33) E. von Mosstsovics.— Japanische Trias-Fossilien’ Sep.-Abdr. aus Beitrage-
zur Pal. sterreich-Ungarns, vol. vil, pp. 163-78. 1888.

(34) E. von Mossisovics.— Obertriadische Cephalopoden-Faunen des Himalaya’
Denkschr. k. Akad. Wissensch. Wien, vol. Ixiii. 1896.

(35) E. von Mossisovics & F. TeLter.— Arktische Triasfaunen’ Mém. Aead..
Imp. Sci. Si. Pétersbourg, ser. vii. 1886.

(36) E. von Mosstsovics.—‘ Die Triadischen Pelecypodengattungen Halobia &
Daonella’ Abhandl. k.-k. Geol. Reichsanst. vol. vii, pt. 2. 1874.

(37) J. PaRK.— Geology of New Zealand’ 1910.

(38) J. Parx.— Permo-Carboniferous Rocks at Mount Mary’ Trans. N.Z. Inst..
vol. xxxvi, pp. 447-53. 1903.

(39) J. Parx.—‘ On the Subdivision of the Lower Mesozoic Rocks of New Zealand’
Trans. N.Z. Inst. vol. xxxvi, pp. 373-404. 1903.

(40) J. Parx.— The Jurassic Age of the Maitai Series’ a N.Z. Inst.
vol. xxxvl, pp- 431-46. 1903.

(41) M. Prrovret.— Note sommaire sur le Trias de la Nouvelle Calédonie’ Bull..
Soc. Géol. France, ser. 4, vol. vill. pp. 324-29. 1908.

(42) J. F. Pompecks.— Ammoniten des Rhat’ Neues Jahrb. vol. 11, pp. 146. 1895.

(43) A. RorupLEetTz.— Perm, ‘Jrias, & Jura-Formationen auf Timor & Rotti’
Paleontogr. vol. xxxix, pp. 57-106. 1892.

(44) J. P. Smiru.— Middle ‘Triassic Marine Invertebrate Faunas of North
America’ U.S. Geol. Surv. Prof. Paper 83. 1914.

(45) R. Sprrent.— Note ona Dyke at Nugget Point’ Trans. N.Z. Inst. vol. xxxvi,. ;

pp. 477-79. 1903.

(46) E. Svzss.— Brachiopoden der Késsener Schichten’ Denkschr. k. Akad..
Wissensch. Wien, vol. vii, pt. 2. 1854.

(47) J. A. THomson.— Materials for the Paleontology of New Zealand’ N.Z. Geol.
Surv. Pal. Bull. No. 1 (1913) pls. i-v. (Plates by J. Hector.)

(48) W. Vorz.—‘ Trias in Sumatra’ Zeitschr. Deutsch. Geol. Gesellsch. vol. li,
pp. 1-60. 1899.

(49) J. Wanner.-—'Triaspetrefakten der Molukken & des Timorarchipels’ Neues
Jahrb. Beilageband xxiv, pp. 161-220. 1907.

(50) J. F. WuHItEavrs.—‘ Fossils ot Triassic Rocks of British Columbia’ Contrib..
to Canad. Pal. vol. 1, pp. 127-49. 1889.

(51) K. v. ZirrEt.— Paliontologie von Neu-Seeland.’ (Novara Reise.) 1864.

(52) H. ZogmMayER.— Untersuchungen tiber Rhatische Brachiopoden’ Beitr. z
Pal. Gsterreich-Ungarns, vol. i, pp. 1-42. 1882.

EXPLANATION OF PLATES XVII-XXV.

Prate XVII.

Fig. 1. Arcestes cf. rheticus W. B. Clark. Rhetic: north-east of Albatross:

Point, Kawhia. Two-thirds of the natural size. Marshall Coll.
(P. 182.)

2. Cladiscites sp. Carnic ; Mount Heslington, Nelson. Natural size..
N.Z. Geol. Surv. Collection. (P. 183.)

3. Clydonautilus (Proclydonautilus) cf. spirolobus Dittmar. Carnic ;.
Nugget Point. One-third of the natural size. N.Z. Geol. Surv.
Coll. (P. 182.)

4, Aulacoceras sp. Noric (?); Oreti Cutting, Hokonui Hills. Two-thirds.

of the natural size. N.Z. Geol. Surv. Coll. (P. 184.)

. Aulacoceras cf. sulcatum Hauer. Natural size. Carnic(?); Eighty-
Hight Valley, Nelson. N.Z. Geol. Surv. Coll. Gutta-percha squeeze..
(P. 184.)

. Orthoceras cf. triadicum Mojsisovies. Carnic ; Otamita, Hokonui
Hills. Natural size. Trechmann Coll. (P. 181.)

. Discophyllites ef. ebneri Mojsisovies. Carnic; Mount Heslington,.
Nelson. One-third of the natural size. Trechmann Coll. (P. 184.)>

Or

or)

~T]

part 3 | THE TRIAS OF NEW ZEALAND. 241

Puate XVIII.

Fig. 1. Conularia cf. levigata Morris. Carnic; Otamita, Hokonui Hills.
Natural size. Trechmann Coll. (P. 189.)
2. Dentalium sp. Carnic; Otamita, Hokonui Hills. Natural size.
Trechmann Coll. (P. 188.)
3. Bowrguetia (2) arata, sp.nov. Carnic; Mount Heslington, Nelson.
Natural size. Gutta-percha squeeze. N.Z. Geol. Surv. Coll.
(P. 188.)
4, Coronaria spectabilis, sp. nov. Carnic; Mount Heslington, Nelson.
Natural size. Gutta-percha squeeze. N.Z. Geol. Surv. Coll.
(P. 137.)
Figs. 5a-5c. Pleurotomaria (Sisenna) hectori, sp. nov. Carnic; Otamita,
Hokonui Hills. Natural size. Trechmann Coll. (P. 186.)
6a-6c. Plewrotomaria (Sisenna) hokonwiensis, sp. nov. Carnic ; Ota-
mita, Hokonui Hills. Natural size. Trechmann Coll. (P. 186.)
Fig. 7. Trochus (Tectus) marshalli, sp.nov. Natural size. Carnic; Otamita,
Hokonui Hills. Marshall Coll. (P. 187.)
Figs. 8a & 8b. Patella (Capulus ?) nelsonensis, sp. nov. lLadino-Carnic ;
Eighty-Eight Valley, Nelson. Natural size. Gutta-percha squeeze.
N.Z. Geol. Surv. Coll. (P. 185.)

PLATE XIX.

Fig. 1. Psewdomonotis ochotica var. densistriata Teller. Upper Noric; Gar-
den Gully, near Wairoa Gorge, Nelson. Right valve. Seven-
eighths of the natural size. Trechmann Coll. (P. 193.)

2. Ditto, var. ambigua Teller. Same locality. Right valve. Natural

“size. Gutta-percha squeeze. Trechmann Coll. (P. 193.)

3. Ditto, cf. var. pachyplewra Teller. Same locality. Left valve.
Seven-eighths of the natural size. Trechmann Coll. (P. 193.)

4, Ditto, cf. var. sparsicostata Teller. Same locality. Left valve.
Seven-eighths of the natural size. Trechmann-Coll. (P. 193.)

5. Ditto, var. eurhachis Teller. Same locality. Right valve. Slightly
reduced. Trechmann Coll. (P. 193.)

6. Ditto, var. acutecostata nov. Same locality. Right valve. Seven-
eighths of the natural size. Gutta-percha squeeze. Trechmann
‘Coll. (P. 194.)

7. Ditto, var. acutecostata nov. Same locality. Left valve. Seven-
eighths of the natural size. Trechmann Coll. (P. 194.)

8. Ditto, very small, cf. var. pachyplewra Teller. Same locality. Left
valve. Seven-eighths of the natural size. Trechmann Coll.
(P. 193.)

Figs. 9a & 9b. Pseudomonotis richmondiana Zittel. Noric; eastern slopes
of Mount Heslington, Nelson. a=right valve; b==left valve.
Seven-eighths of the natural size. N.Z.Geol. Surv. Coll. (P. 194.)

Fig.10. Monotis salinamia Bronn. Noric(?); Okuku, Canterbury. Seven-
eighths of the natural size. Left valve. N.Z. Geol. Surv. Coll.

(P. 195.)
PLATE XX.
Fig. 1. Monotis salinaria Bronn, var. intermedia nov. Noric(?); Okuku,
; Canterbury. Left valve. Natural size. N.Z. Geol. Surv. Coll.
uP, 196.)

2. Monotis salinaria Bronn, var. hemispherica nov. Noric(?); Okuku,
Canterbury. Left valve. Natural size. N.Z. Geol. Surv. Coll.
(P..196.)

3. Ditto, same locality. Right valve. Natural size. N.Z. Geol. Surv.
Coll. (P. 196.)

242 DR. C. T. TRECHMANN ON [ vol. xxii,

Fig. 4. Hokonuia limeformis, gen. et sp.nov. Carnic; Otamita, Hokonui
Hills. Right valve. Natural size. Trechmann Coll. (P. 204.)

Figs.5a & 56. Hokonwa cf. rotundata, sp.nov. Carnic; Mytilus-problema-
ticus Bed, Nugget Point, Otago. a=left valve; 6 = anterior
portion of beak-region of the same specimen. Natural size.
Trechmann Coll. (P. 205.)

Fig. 6. Halobia zitteli Lindstrém, var. zealandica nov. Carnie; Mount.
Heslington, Nelson. Right valve. Two-thirds of the natural size.
Trechmann Coll. (P. 197.)

7. Daonella indica Bittner. Ladino-Carnic ; Caroline Cutting, Hoko-
nui Hills. Portion of a large right valve. Natural size.
Trechmann Coll. (P. 196.)

8. Mytilus (2) problematicus Zittel. Carnic; Highty-EHight Valley, near
Nelson. Left valve of a small specimen. Natural size. Trech-
mann Coll. (P. 201.)

Figs. 9a &9b. Mytilus (2) mirabilis, sp.nov. Carnic; Mytilus-problematicus
Bed, Highty-Eight Valley, near Nelson. Right valve: a=an-
terior; b=posterior view. Half of the natural size. Trechmann
Coll. “(P. 202.)

PLATE XXI.

Fig. 1. Halobia zitteli Lindstrom, var. zealandica nov. Carnic; Otamita,
Hokonui Hills. Seven-eighths of the natural size. Right valve.
Trechmann Coll. (P. 197.)

2. Ditto. Samelocality. Seven-eighths of the natural size. Left valve...
Trechmann Coll. (P. 197.) ~

3. Halobia hochstetteri Mojsisovies. Carnic; Mount Heslington, Nel-
son. Natural size. Right valve. Trechmann Coll. (P. 199.)

4, Halobia cf. austriaca Mojsisovies. Carnie; Otamita, Hokonui
Hills. Seven-eighths of the natural size. Right valve. Trech-
mann Coll. (P. 200.)

5. Daonella indica Bittner. Ladino-Carnic; Caroline Cutting, Hokonui
Hills. Seven-eighths of the natural size. Trechmann Coll. (P.196.)

6. Plewrophorus zealandicus,sp.nov. Carnic; Otamita, Hokonui Hills.
Somewhat reduced. Left valve. Marshall Coll. (P. 212.)

7. Cardiomorpha (?) nuggetensis, sp. nov. Carnic; Nugget Point,
Otago. Somewhat reduced. Trechmann Coll. (P. 189.)

8. Anodontophora edmondiiformis, sp. nov. Carnic ; Otamita, Hokonui.
Hills. Somewhat reduced. Left valve. Trechmann Coll. (P. 208.)

9. Anodontophora ovalis, sp. nov. Carnic; Otamita, Hokonui Hills.
Somewhat reduced. Trechmann Coll. (P. 208.)

10. Anodontophora angulata, sp. nov. Carnic ; Otamita, Hokonui Hills.
Somewhat reduced. Trechmann Coll. (P. 208.)

11. Paleocardita quadrata, sp. novy.-. Carnic; Nugget Point, Otago.
Natural size. Left valve. Trechmann Coll. (P. 212.)

12. Macrodon ef. curionii Bittner. Carnic; Otamita, Hokonui Hills.
Natural size. Left valve. Trechmann Coll. (P. 191.)

13. Macrodon sp. Carnie; Mount Heslington, Nelson. Natural size.
Gutta-percha squeeze. Interior of right valve. N.Z. Geol. Surv.
Colla (R219)

14. Pseudoplacunopsis placentoides, sp. nov. Carnic; Otamita, Hokonui
Hills. Natural size. Attached valve. Trechmann Coll. (P. 209.)

15. Ditto. Carnic; Otamita, Hokonui Hills. Natural size. Upper valve.
Trechmann Coll. (P. 209.)

16. Lima (Limatula) ef. pichleri Bittner. Carnic; Mount Heslington;
Nelson. Natural size. Gutta-percha squeeze. Left valve. Trech-
mann Coll. (P. 206.)

17. Megalodon globularis, sp. nov. Carnic; north side of entrance of
Wairoa Gorge, Nelson. Natural size. Gutta-percha squeeze
Trechmann Coll. (P. 209.)

part 3] THE TRIAS OF NEW ZEALAND. 243:

Fig. 18. Pecten sp. Carnic; Nugget Point, Otago. Natural size. Gutta-

percha squeeze. Left valve (?). Trechmann Coll. (P. 206.)

19. Cassianella sp. Carnic; Otamita, Hokonui Hills. Natural size.
Left valve. Trechmann Coll. (P. 206.)

20. Leda semicrenulata, sp. nov. Carnic; Otamita, Hokonui Hills.
Natural size. Trechmann Coll. (P. 191.)

21. Palzoneilo otamitensis, sp. noy. Carnic; Otamita, Hokonui Hills.
Natural size. Right valve. Trechmann Coll. (P.190.) 8

22. Palzoneilo cf. preacuta Klipstein. Carnic; Otamita, Hokonui

_ Hills. Natural size. Trechmann Coll. (P. 190.)

PuatTe XXII.

Fig. 1. Hokonwia rotwndata, gen. et sp.nov. Carnic. Mount Heslington,.
Nelson. Natural size. Gutta-percha squeeze. Right valve. N.Z.
Geol. Sury. Coll. (P. 205.)

2a. Hokonuia limeformis, sp. nov. Carnic ; Otamita, Hokonui Hills.
Two-thirds of the natural size. Right valve. Trechmann Coll.
(P. 204.)

2b. Same specimen. Anterior portion of hinge showing tongue-like
shelly process. Natural size. (P. 204.)

8. Hokonwia cf. rotwndata, sp. nov. Carnic; Highty-Hight Valley,
Nelson. Natural size. Gutta-percha squeeze. Interior of left:
valve. Trechmann Coll. (P. 205.)

Figs. 4a & 46. Hokonwia cf. rotundata, sp. nov. Carnic; Wairoa Gorge,
Nelson. Three-quarters of the natural size. Left valve; b=
anterior view. N.Z. Geol. Sury. Coll. (P. 205.)

Fig. 5. Hokonwia limeformis, sp. nov. Carnic; Otamita, Hokonui Hills.
Right valve. Natural size. Trechmann Coll. (P. 204.)

6. Anisocardia parvula, sp. nov. Carnic; Otamita, Hokonui Hills.
Thrice the natural size. Gutta-percha squeeze. Right valve.
Trechmann Coll. (P. 213.)

7. Ditto. Same locality. Thrice the natural size. Gutta-percha
squeeze. Left valve. Trechmann Coll. (P. 213.)

8. Myophoria otamitensis, sp. nov. Carnic; Otamita, Hokonui Hills.
Natural size. Trechmann Coll. (P. 211.)

9. Myophoria heslingtonensis, sp. nov. Carnic; Mount Heslington,
Nelson. Thrice the natural size. Gutta-percha squeeze. Right.
valve. N.Z. Geol. Surv. Coll. (P. 211.)

10. Myophoria nuggetensis, sp. nov. Carnic; Nugget Point, Otago.
Natural size. Gutta-percha squeeze. Trechmann Coll. (P. 210.)

11. Pinna sp. Carnic; Highty-Eight Valley, Nelson. Natural size.
Left valve. N.Z. Geol. Surv. Coll. (P. 206.)

PuatTE XXIII.

Figs. la & 1b. Halorella zealandica, sp. nov. lLadino-Carnic; Caroline
Cutting, Hokonui Hills.. Natural size. Cast of ventral and dorsal
valves. Trechmann Coll. (P. 216.)
Fig. 2. Ditto. Same locality. Natural size. Gutta-percha squeeze of ven-
tral valve. Trechmann Coll.
3. Ditto. Same locality. Natural size. Gutta-percha squeeze of ven-
tral beak and dorsal valve. Trechmann Coll.
4, Halorella sp. ef. pedata var. multicostata Bittner. Carnic; Eighty-
Hight Valley, Nelson. Natural size. Dorsal valve. N.Z. Geol.
pew, ©oll, (P. 217.)
5. Dielasma zealandica, sp. nov. lLadino-Carnic; Caroline Cutting,
Hokonui Hills. Three-quarters of the natural size. Cast,
dorsal aspect. Trechmann Coll. (P. 217.)
6. ‘ Terebratula’ pachydentata, sp. nov. Carnie; Otamita, Hokonui
Hills. Natural size. Dorsal aspect. Trechmann Coll. (P. 218.)

244 DR. C. T. TRECHMANN ON [vol. xxiii,

Fig. 7. Terebratula (Cenothyris 2) sp. Noric, Pseudomonotis Bed; Rich-
mond, Nelson. Natural size. Gutta-percha squeeze. Dorsal
aspect. Trechmann Coll. (P. 218:)

8. Terebratula cf. hungarica Bittner. Carnic; Otamita, Hokonui Hills.
Natural size. Dorsal aspect. Trechmann Coll. (P. 219.)

9. Mentzelia cf. ampla Bittner. Rhetic; Kawhia. Natural size.
Dorsal aspect. Trechmann Coll. (P. 228.)

Figs. 10a & 106. Mentzelia kawhiana, sp. nov. Rhetic; Kawhia. Natural
size. a=ventral; b=dorsal aspect. Teeter Coll. (P. 228.)

Fig. 11. Mentzeliopsis spinosa, gen. et sp.nov. Kaihiku Beds, Ladino-Carnic ;
Caroline Cutting, Hokonui Hills. Natural size. Gutta-percha
squeeze of dorsal valve. Trechmann Coll. (P. 230.)

12. Ditto. Same locality. Natural size. Gutta-percha squeeze of
another dorsal valve. Trechmann Coll.

18. Ditto. Same locality. Natural size. Gutta-percha squeeze of a
ventral valve. Trechmann Coll.

14. Ditto. Same loeality. Natural size. Gutta-percha squeeze of
another ventral valve. Trechmann Coll.

15. Ditto. Same locality. Natural size. Gutta-percha squeeze of the
interior of a ventral valve showing the median septum and the
external spines. Trechmann Coll.

16. Ditto. Kaihiku Beds; North Peak, Hokonui Hills. Cast, the spines
destroyed, showing the ventral median septum and dental plates.
Natural size. N.Z. Geol. Surv. Coll.

17. Mentzeliopsis horrida, sp. nov. Kaihiku Beds, Ladino-Carnic ;
Caroline Cutting, Hokonui Hills. Gutta-percha squeeze of dorsal
valve. Natural size. Trechmann Coll. (P. 230.)

‘_. 18. Ditto. Same locality. Gutta-percha squeeze of the euiteal valve

- of another specimen. Natural size. Trechmann Coll.

Figs.19a &19b. Spiriferina (?) caroline, sp. nov. Kaihiku Beds, Ladino-
Carnie; Caroline Cutting, Hokonui Hills. Natural size. Gutta-
percha squeeze: a=the interior; b=the exterior of a ventral valve.
Trechmann Coll. (P. 226.)

Fig. 20. Ditto. Same locality. Natural size. Gutta-percha squeeze of the
exterior of a dorsal valve. Trechmann Coll.

21. Retzia schwageri Bittner. Carnic ; Mount Heslington, Nelson. Gutta-
percha squeeze. Dorsal aspect. Natural size. Trechmann Coll.
(PB: 228.)

PLATE XXIV.

Fig. 1. Spiriferina diomedea, sp. nov. Rhetic. South Hillend, near the
Hokonui Hills. Gutta-percha squeeze of a dorsal valve and part of
the ventral area. Natural size. Marshall Coll. (P. 222.)
2. Ditto. Rhetic: Nugget Point, Otago. Natural size. Dorsal aspect,
the wings broken. N.Z. Geol. Surv. Coll. (P. 222.)
3. Spiriferina acutissima, sp. nov. Noric(?); east side of Mount
Heslington, Nelson. Gutta-percha. squeeze, dorsal aspect. Natural
size. N.Z. Geol. Surv. Coll. (P. 221.)
4. Spiriferina gypaetus, sp. nov. Noric(?); South Peak, Benmore,
Hokonui Hills. Cutta-percha squeeze, dorsal aspect. Natural size.
N.Z. Geol. Surv. Coll. (P. 221.)
5. Spiriferina ef. austriaca Suess. Lower Carnic(?); Mount Potts.
Dorsal aspect. Natural size. N.Z. Geol. Sury. Coll. (P. 224.)
Figs. 6-8. Spiriferina nelsonensis, sp. nov. Carnic; western slopes of Mount
Heslington, Nelson. Natural size. Gutta-percha squeezes: 6=
a dorsal valve and ventral area; 7=exterior of a ventral valve;
8=ventral area; of three different examples. Trechmann Coll.
P. 2238.)

Quart. Journ. Geor. Soc. Vor. LXXIII, Pr. XVII.

a Srey

AT glia Re sheen ea He

Bemrose, Collo., Derby.

T., photo.

TRIASSIC CEPHALOPODA From NEW ZEALAND.

j ~ Quart. Journ. Geo. Soc. Vor. LXXIII, Pr.XVIII.

.M. Woodward, del.
rT., photo. Bemrose, Collo., Derby.

TRIASSIC GASTEROPODA, etc. FRom NEW ZEALAND.

Quart. Jouan. Geot. Soc. Vor. LXXIIl, Pt.XIX.

Bemrcse, Collo., Derby.

-TT., photo.

PSEUDOMONOTIS anv MONOTIS.

Quart. Journ. Geor. Soc. Vor. LXXIII, Pu. XX.

. M. Woodward, del. | Bemrose. Collo.. Derby.
TRIASSIC LAMELLIBRANCHS From NEW ZEALAND.

a

4

Quart. Journ. Geov. Soc. Vor. LXXIll, Pi. XXI.

oT. photo. Bemrose,Colio, Derby.

TRIASSIC LAMELLIBRANCHS From NEW ZEALAND.

Quart. Journ. Geov. Soc. Vor. LXXII, PuXXil.

Pa. X%

.M.Woodward, del.
a l., photo. Bemrose, Collo., Derby.

TRIASSIC LAMELLIBRANCHS From NEW ZEALAND.

Quart. Journ. GEOL. Soc. Vor. £XXill, PL. XXIII.

G. M. Woodward, del.
.1.1., photo. Bemrose, Collo., Derby.

TRIASSIC BRACHIOPODA From NEW ZEALAND.

Quart. Journ. Geot. Soc. Vou. LXXII, Pr. XXIV.

G.M.Woodward, del.
at. 1, photo. Bemrose, Collo., Derby.

TRIASSIC SPIRIFERINZ From NEW ZEALAND.

w

Quart. Journ. GEOL. Soc. Vor. LXXIII, Pr. XXV.

_G.M. Woodward, del.
1. 1., photo. Bemrose. Collo., Derby.

TRIASSIC BRACHIOPODA From NEW ZEALAND.

i
>

- part 3] THE TRIAS OF NEW ZEALAND. 245

Figs. 9a & 9b. Spiriferina otamitensis, sp. nov. Carnic ; Otamita, Hokonui
Hills. a=dorsal ; b=ventral valve of a rather crushed example.
; Natural size. Trechmann Coll. (P. 225.)

10-12. Spiriferina fragilis Schlotheim. Kaihiku Beds, Ladino-Carnic ;
Caroline Cutting, Hokonui Hills. Natural size. Gutta-percha
squeezes: 10—ventral; 11 & 12=dorsal valves. Natural size.
Trechmann Coll. (P. 219.)

13a &13b. Spiriferina suwessi Winkler, var. australis noy. Carnic,
Halobia Beds; Mount Heslington, Nelson. Naturalsize. a=dorsal;

- b=ventral aspects of the same example, a cast. Trechmann Coll.
(Pi/225.)
Fig. 14. Ditto. Same locality. Gutta-percha squeeze of the exterior of a
ventral valve. Natural size. Trechmann Coll.
15. Spiriferina kaihikuana, sp. nov. Kaihiku Beds, Ladino-Carnic ;
Highty-Eight Valley, Nelson. Gutta-percha squeeze of the exterior
of a dorsal valve. Natural size. N.Z. Geol. Surv. Coll. (P. 220.)

PuaTE XXV.

Figs.1a &1b. Hectoria bisulcata, gen. et sp. nov. (Hector). Rhetic; Ka-
whia. Natural size. a=dorsal; b=ventral aspect. Trechmann
Coll. (P. 225.)

Fig. 2. Hectoria tumida, sp. nov. Rhetic; Benmore, Hokonui Hills.
Natural size. Gutta-percha squeeze of a ventral beak and a dorsal
valve. Trechmann Coll. (P. 236.)

3. Hectoria sp. Taylor’s Creek, Hokonui Hills. Natural size. Wea-
thered cast showing the spiralia. Ventral aspect. N.Z. Geol. Surv.
Call (P: 233.)

Figs.4a &4b. Hectoria cwneiformis, sp. nov. Jurassic, Taylor’s Creek,
Hokonui Hills. Natural size. a=ventral aspect; b=section.
N.Z. Geol. Surv. Coll. (P. 287.)

Fig. 5. Spirigera kaihikuana, sp. nov. Ladino-Carnic; Cowan’s Railway-
station, Hokonui Hills. Natural size. Dorsal aspect. N.Z. Geol.
Surv. Coll. (P. 231.)

Figs. 6a & 6b. Spirigera wreyi Zittel. Carnic; western slope of Mount Hes-
lington, Nelson. Natural size. a=dorsal aspect; b=section.
Trechmann Coll. (P. 231.)

Figs. 7a & 7b. Spirigera manzavinioides, sp.nov. Carnic; Otamita, Hokonui
Hills. Natural size. a=dorsal; b=ventral aspect. Trechmann
Coll. (P. 282.) .

DISCUSSION.

Dr. F. A. Barner was glad to find a British geologist and
paleontologist tackling these complicated problems of New Zealand
geology with such success. Ever since he himself had described
Torlessia, he had wished to know the age of the supposed Maitai
Beds near Mount Torlesse, where this presumed annelid was found.
Did the Author include them in those which he now referred to
the Permo-Carboniferous, or would he parallel them with the
Yakutat Slates of Liassic age, or would he leave them in the
Trias ?

The Aurion, in reply, stated that the true relationship of the
Mount-Torlesse Annelid Beds was still one of the unsolved problems
of New Zealand geology. The question of their stratigraphy is
discussed by McKay and others, and the evidence seems to show

Q.J.G.S. No, 291, U

246 THE TRIAS OF NEW ZEALAND. [ vol. Ixxiu,

that they form the upper part of the Maitai Series. The Annelid
Beds have not been traced in the Nelson district, the classical area
of the Maitai Series; but he had himself found a piece of annelid-
like tube in the Maitai Limestone of the Wairoa Gorge, accom-
panied by Zaphrentis and Permo-Carboniferous brachiopods.

He did not think the Mount-Torlesse Annelid Beds in any
way equivalent to the Yakutat Slates of Alaska, as he had shown
that the large bivalve in the Maitai Argillites overlying the Lime-
stone near Nelson, formerly supposed to be Jnoceramus, 1s ap-
parently identical with Aphanaia L. G. de Koninek, of the
Permo-Carboniferous of New South Wales.

Inoceramya Ulrich, of the Yakutat Slates, is a shell of the
Inoceramus group, and bears a row of areal ligament-pits. The
Lias, or at least the Lower Jurassic, is a well-defined formation
in New Zealand, where it overlies the Trias, and in no way
resembles the Annelid Beds.

He felt much interest in the fact that Dr. Bather had determined
the scanty crinoid remains that he collected in the Kaihiku Beds
as rather of Upper than of Middle Triassic age. All evidence that
these deposits were Permian or Lower Trias seemed now entirely.
removed.

part 3] TRIASSIC CRINOIDS FROM NEW ZEALAND. 247

8. The Triassic Crrnotps from New ZeEauann, collected by
Dr. C. T. Trecumann. By Francis ArrHur BAtHER,
M.A., D.Sc., F.R.S., F.G.S. -(Read February 7th, 1917.)

Dr. TrecumMann has kindly presented to the British Museum
(Natural History) a stem-fragment and a piece of calcareous sand-
stone containing imprints of various columnals, and has asked me
to furnish some notes on them. Since these are the first Triassic
erinoids to be described from New Zealand, their adequate descrip-
tion seems warranted, despite their fragmentary condition. All are
believed to represent new species.

In 1909 most of the Triassic crinoids known up to date were
discussed by me in ‘Triassic Echinoderms of Bakony,’! and the
terminology here employed is explained in that memoir. Since
then the only professedly new forms made known are those con-
tained in Clark & Twitchell, 1915, «The Mesozoic & Cenozoic
Echinodermata of the United States’ (U.S. Geol. Surv. Monogr.
liv). hese, therefore, are discussed here at greater length than
the better-known European species, and for one of them a new
specific name is proposed.

[Mr. G. C. Martin, in a paper on ‘Triassic Rocks of Alaska,’
published December 1916 (Bull. Geol. Soc. Amer. vol. xxvu,
pp. 685-718), but not received here until June 1917, records
specimens of ‘ Pentacrinus.’ These, which belong to two new
species of Jsocrinus, are also described and compared. |

ENTROCHUS UNDATUS, sp. nov. (Figs. 1 & 2, p. 248.)

Diagnosis.—Trochitz with smooth, faintly convex side-faces ;
ratio of height to diameter circa O° 18; joint-face with about
25 coarse il developed ridges, radiating “Boar the centre about
halfway to the periphery, where they merge into a few broad,
irregular waves.

Locality.—Highty-Hight Valley, Nelson, (N.Z.).

Horizon.—Kaihiku Beds, Ladino-Carnie.

Material.—A stem-fragment consisting of 24 columnals or
portions of columnals, broken cleanly across at the joint-face,
between the 5th and 6th, and worn all down one side, especially
towards the other end of the fragment. British Museum, Geological
Department, H 22185.

Description.—Cylindrical.

Length of fragment=—38 mm.

Average height of columnal, as caleulated=1'58 mm.

Greatest height of a columnal, as measured=1°8 mm.

Least height of a columnal, as measured=1'5 mm.

Diameter = 8'2 mm. at the more imperfect end; —10 mm. at the other.

Ratio of height to diameter=0°'18.
Diameter of lumen=about 0°8 mm.

1 «Result. Wissensch. Erforsch. des Balatonsees’ vol. i, Pal. Anhang.

Entro

chi and Pentacrint from New Zealand and North America.

[Figs. 1 and 3 are of the natural size. All the rest are enlarged 4 diameters.
Drawn by Miss Margaret Tempest. |

Fig.

=
2
io»)

Fig. 9.

10
Lal
12
13

Fig. 14.

Fig. 15

STD OVE gp

Entrochus undatus. (Pp. 247-49.)
. Holotype. Side view; the thicker suture-line, fifth from the top, represents
the division between the two fragments. [KH 22185. }
. Holotype. Joiut-face at the top of the larger fragment.

Entrochus ternio. (P. 249-52. )
Holotype. Side view. [E 22186.]
Holotype. Joint-face.
Group B. Joint-face with the characters of the holotype.
Group B. Joint-face with ridges péntamerously fasciculated.
Group C. Joint-face of young.

Encrinus hyatti W. B. Clark. (P. 251.)
. Joint-face. [FE 6481. }
Tsocrinus trechmanni. (Pp. 252-53.)

Normal joint-face. In this example there is a marked peripheral rim, and the
radial ridge-groups are gable-shaped. [E 22186. |

. Joint-face of a small epizygal with no ridges. | E 22187. ]

. Syzygial joint-face with traces of ridges. [E 22187.]}

. A wide asymmetrical brachial. [EF 22187. |

. A pinnular, or a symmetrical brachial from the distal region. [KE 22187. ]

Tsocrinus cupreus. (Pp. 255-56.)
Normal joint-face. In this the secondary or accidental radial depressions are
less marked than in most. [FE 22178.]

Tsocrinus gravine. (P. 256.)
. Normal joint-face. {EK 22181.]

ee

part 3] TRIASSIC CRINOIDS FROM NEW ZEALAND. 249

Sides smooth, faintly convex, rising about 0-1 mm. above the
suture-line.

Suture-lines broadly and irregularly waved, not crenelate in the
ordinary sense.

The joint-face shows faint traces of radiating ridges in the
central area, but at about halfway to the periphery these die away
with varying rapidity. The number of these ridges is estimated
at 25-; it is not possible to see whether they are grouped by fives
to any extent. ‘The ridges and grooves are of equal size. The
peripheral half of the joint- -face is almost smooth; but in places
there can be detected the traces of the radiate ridges, also faint
concentric grooves. The whole surface is thrown te very slight
broad waves, 5 or 6 in all, which bear no obvious relation to the
ridges.

The lumen is obscurely pentagonal, and is indicated in the fossil
by a calcite infilljpg of darker colour. Within this, at all four
places where it is exposed there is visible a structure with a light
border, which may be interpreted as probably an axial vessel,
possibly with five chambers (compare Bather, 1909, pp. 41, 42).

Relations of the species.—The circular section, smooth
exterior, apparent absence of cirri, small lumen. and radiating
ridges on the joint-face:-all these are characters ot the Hnerinus
stem, and to that genus the present specimen probably belongs.
Rone the less, in the absence of evidence from the crown, and in
view of the distinctive characters of the joint-face, it is safer
to give the specimen for the present the non-committal name
Entrochus.

From all known species of Hnerinus, and from all Entrochi as
yet described from Triassic rocks, the H/ntrochus here described
differs in the substitution of broad irregular waves for the radi-
ating ridges in the peripheral area of the joint-face, resulting in a
waved non-crenelate suture-line. Hence the trivial name, wndatus,
waved.

ENTROCHUS TERNIO, sp. nov. (Figs. 3-7, p. 248.)

Diagnosis.—Trochite with smooth, faintly convex side-faces ;
ratio of height to diameter=0°35 (more in ‘young) ; suture de-
pressed, crenelate ; joint-face with a raised* central area, and from
20 to 30 well- arte ridges, of which two-thirds tend to constitute
forked pairs starting from the centre, and one-third to be shorter
ridges intercalated between the pats.

Loeality.—Caroline Cutting, Hokonui Hills, Southland (N.Z.).

Horizon.—Kaihiku Beds, Ladino-Carnice.

Material—Various imprints of columnals on a fragment
of calcareous sandy matrix with iron-stained imprints and in-
ternal casts of Spiriferina Sragilis, Dielasma cf. himalayana,
Mentzeliopsis, and Isocrinus. British Museum, Geological Depart-
ment, EH 22186. The imprints of columnals may be erouped under
three headings. (A) A stem-fragment consisting of 3 columnals,

Ml i eS i, Pa TEE ie A RG BETES EE IS LENS EAE AE ALLEGE AL EOE GLE I! ET LE IE NEL NO IO OBE

250 DR. F. A. BATHER ON TRIASSIC [vol. lxxin,

and showing the clear impression of one joint-face. This, which
is believed to represent the adult stage, is fixed on as the holotype.
(B) Three smaller separated columnals, visible in rather imperfect
imprints, not far from the holotype. (C) Two small united
columnals, and, at 16 mm. distance from them, the imprint of a
small joint-face. These three sets will now be described in order.

Description of A, the holotype (figs. 3 & 4, p. 248).—
Cylindrical.
Length of fragment=—5'8 mm.
Diameter =5°7 mm.

Height of a columnal, as measured=2 mm. Ratio to diameter —0- 35.
Diameter of lao eiren 0°4 mm. (not more).

Sides smooth, faintly convex; suture depressed.

Suture-lines with large, rounded, well-marked crenelle.

The joint-face shows a raised area round thetlumen, and outside
this about 28 radiating ridges, which tend to be arranged so that
about a third start foe the central area and fee while the
remaining 9 are intercalated between these pairs. I is this arrange-
ment by threes that has suggested the trivial name fternio, a
number containing threes.

Description of Group B (figs. 5 & 6, p. 248).—The three
columnals are all of about equal size, with the following ap-
proximate measurements :—

Diameter=3'7 mm.
Height=1°8 mm. Ratio to diameter=0°48.
Diameter of lumen=0°'25 mm.

In the best-preserved joint-face (fig. 5) there are about 22
ridges, arranged in pairs with a shorter one intercalated, as in the
holoty pe.

The joint-face of the adjacent imprint (fig. 6) has a smooth and
flat central area, at a level shghtly below the ridges. This area is
larger than in the other cases, so that the ridges are shorter.
Their number is estimated at not less than 22, antl they appear to
lie in five fascicles of 4 or 5, those in each faeces being parallel
to the median line of that aces

These smaller columnals are ranked with the holotype, as pro-
bably belonging to the same species. The characters in which
they ditter from the holotype are, on the whole, those of youth.
With this the relativ ely greater height of the columnals is con-
sistent, though perhaps rather more than might have been expected
on that interpretation. J have previously suggested C19082p2 9)
that the pentamerous fasciculation of the ridges is a frequent,
possibly universal, characteristic of youth in the genus Hnerinus.
It may, however, be manifested in certain regions of the stem and
absent from others. In some species. the character passes into the

adult stage, and in genera of later origin becomes a norma] feature
(1909, p. 249). See p- 251, under ‘Relations.’

part 3] CRINOIDS FROM NEW ZEALAND. 251

Description of Group C (fig. 7, p. 248).—The stem-
fragment composed of two columnals is cylindrical.

Diameter of columnal=2°3 mm.
Height of columnal=1'25 mm. Ratio to diameter=0°54.
Diameter of lumen=0°25 mm.

Sides smooth, very faintly convex, almost straight.

Suture-lines with large, rounded, well-marked crenelle.

The joint-face shows a raised area round the lumen, with a
diameter of about 0°6 mm., and outside this are 10 radiating ridges,
rapidly broadening.

The other imprint also has 10 ridges. Its diameter is 1°6 mm.

These specimens may represent a still younger stage. If from
the holotype’s total of 28 we were to eliminate the shorter inter-
calated ridges, there would be left about 10 pairs of bifurcating
ridges, and each of those pairs would in its early stage appear as a
single rapidly broadening ridge.

Relations of the species.—At first sight the characters of
these imprints seem of so indifferent or uncritical a nature as not
to warrant the establishment of a new species. I have, however,
worked through the descriptions of published species without
finding any that agree with the diagnosis here presented. Perhaps
one would not expect to find the same species in the European or
even in the American province; but neither is there anything
of the kind in the Triassic material from Timor that Prof. J.
Wanner has kindly entrusted to me for description. Among
European species similar jomt-faces are found in the Carnie rocks
rather than in the Ladinic, where the sharply-cut cog-wheel type,
familar in Encrinus liliiformis, is dominant.

A tendency to bifurcation and intercalation of ridges on the
same planasin Entrochus ternio is observable in Entrochus insignis
Toula. Specimens of this from the type-locality in Bulgaria were
most kindly sent to me by Dr. P. Bakalow (Brit. Mus., Geol. Dept.,
E 14076), who has proved their Triassic age [probably Raiblan ].
This species shows a far more marked pentamerous fasciculation of
the ridges than anything hinted at in H. ternio, together with a
beginning of petals and radial ridge-groups.

An earlier stage of that development is found in Enerinus
hyatti W. B. Clark (1915), from the Upper Trias of California.
Clark lays stress on the bifurcating striations (which, by the way,
are scarcely shown in his figure) ; but he has not observed other im-
portant characters. Ina specimen (fig. 8, p. 248) which Prof. Clark
was so good as to give me many years ago (now Brit. Mus., Geol.
Dept., E 64:81) there are shorter intercalated ridges as in EH. in-
signis, not so regular as in EH. ternio. Further, the ridges are
clearly gathered in 5 fascicles surrounding a relativ ely_ large,
raised, central area, which thrusts out 5 wedges between the
fascicles, each wedge splitting (as it were) one of the ridges and
compressing the other ridges into a fan as it forces the limbs of

252 DR. F. A. BATHER ON TRIASSIC [vol. xxiii,

the split one asunder. These split ridges may be the beginning
of either the radial ridge-groups or the petals; their relations to
the lumen are obscure, but they coincide with the angles of the
periphery, which is irregularly and faintly pentagonal. The ridges
of Hnerinus hyatti are coarser than those of Hntrochus insignis,
finer than those of EH. ternio. The characters observed are con-
firmed by squeezes (Brit. Mus., Geol. Dept., E 21819) very kindly
made by Prof. Bassler from specimens studied by Prof. Clark and
now in the U.S. National Museum.

IsOCRINUS TRECHMANNT, sp. nov. (Figs. 9-18, p. 248.)

Diagnosis.—Transverse section normally a rounded pentagon,
at the syzygy a rounded star. Height less than one-third of the
diameter. Side-faces smooth, straight. Suture-line flush, faintly
or not at all crenelate. Normal joint-face with lumen minute ;
central area raised, smooth, narrow, continuous with the radial
erenelle; petal-Hoors raised generally to the level of the crenelle,
smooth, narrow, long; radial ridge-groups about 3, inosculating
more often than gable-shaped, the distal pair meeting at an angle
of about 90°; peripheral crenelle 6 to 8, passing from the inter-
radius towards the periphery at an angle which gradually increases
to a right angle in the more acentral ridges; all confluent on the
periphery.

Locality.—Caroline Cutting, Hokonui Hills, Southland (N.Z.).

Horizon.—Kaihiku Beds, Ladino-Carnie.

Material.—Various imprints of columnals on the same rock-
fragment as Entrochus ternio. British Museum, Geol. Dept.,
E 22186, E 22187. The holotype is the imprint of a normal
joint-face on the latter piece, not the example drawn in fig. 9.

Description.—The transverse section of a normal internodal
is a pentagon, usually rounded, with sides sometimes slightly convex.
A few that show signs of excavation of the sides probably lay just
above the nodes, and received the cirri in their hollowed sides. One
such is almosta pentapetalon. Measurements of normal internodals
are :—

Diameter=2 mm., 2°3 mm., 2°8 mm.
Height—0°'75 mm.; ratio to diameter=0°27.

Side-faces straight and unornamented.

Suture-lines flush, nonerenelate in normal internodals; perhaps
obscurely crenelate at or near syzygies.

J oint-faces.—Normal internodal (fig. 9, p.248): lumen minute,
say O'l mm., its section not distinct; central area raised, smooth,
narrow, continuous with the radial crenelle; petal-floors raised
generally to the level of the crenellz, smooth, narrow, long; radial
ridge-groups about 3, inosculating more often than gable-shaped,
the adcentral pair tending to fuse with the central area, the
acentral meeting at an angle of about 90°; peripheral crenelle
3 or 5 in small ossicles, from 6 to 8 in full-sized ones (9 in the

part 3] CRINOIDS FROM NEW ZEALAND. 253

pentapetalon), passing from the interradius towards the periphery
at an angle which gradually increases to a right angle in the more
acentral ridges: all confluent on the periphery.

Syzygial face (seen in one imprint, fig. 11, whether epi- or hypo-
zygal uncertain): sides of rounded pentagon faintly excavate ; lumen
and central area larger than in the normal face, the area slightly
raised; petal-floors wide, and flush or slightly depressed ; perradial
ridge-groups 2, the adcentral one a mere granule, the acentral one
lambdoid with the stem broadening to form part of the peripheral
rim; peripheral crenellz restricted to one on each side of the lamb-
doid stem, but the rim is continuous, though faint, and a couple of
slight swellings on it represent the interradial crenellze.

There is one small imprint (fig. 10) that appears to be of an
epizygal, but it is not very clear. It is a rounded star, with
diameter=1°‘Smm.; [R=] mm.; r=0°5 mm.; lumen minute, but
distinct, relatively ioe. apparently pentagonal ; ridges invisible ;
petal-floors shghtly depressed; rim indistinct. The side-faces of
this columnal were vertically concave, and apparently bore a
depressed, elliptical cirrus-facet.

Cirrals appear to be represented by imprints of a few small
canaliculate ossicles.

Brachials.—There are a few scattered imprints of articular
faces, which probably represent brachials. of this species. There
are wide brachials from the proximal region (fig. 12), narrower
and more elevated ones from the distal region (fig. 13); one wide
brachial shows a syzygial face. All have the axial canal well
‘developed, and in this respect resemble the brachial from the
Raiblian Cardita-Oolite of Rammelsbach, figured in ‘Triassic
Echinoderms of Bakony’ (1909, pl. v, fig. 122) rather than the
brachial from the Cassian Beds of Cserhat (op. c7t. pl. v, fig. 127).

Relations of the species.—The joint-faces of three European
Triassic species (J. propinguus, I. hercunie, I. bavaricus) are
distinguished from J. trechmanni by the presence of a radial
triangle. The absence of a rim and the consequent crenelation of
the suture-line distinguish L. tyrolensis, I. scipio, and L. sceptrum.
I. amenus is further characterized by the marked ornament of its.
side-faces, and I. candelabrum by the long curved ridges of its
joint- face. In f. dubius (Goldfuss) the crenellee are confluent
with the periphery, but that species, to judge from the original
figures, has wider petal-floors than I. trechmannz, with a oreater
distinction between the radial ridge-groups and the per ‘ipheral
ridges. J. dubiws needs careful redescription on the basis of the
original material; meanwhile, it is with it and similar forms that
I. trechmanni should be associated.

Turning to the Triassic species of North America, the characters.
of which te lately been sketched by Prof. W. B. Clark (1915),
we find three species, which may be discussed briefly.

Tsocrinus smithi, from the Lower Tri las, is represented by
weathered columnals. The section in the specimen as figured is a

Q. J.G.S. No. 291. x

254 DR. F. As BATHER ON TRIASSIC [ vol. lexi,

rounded star, with diameter = 2°85 mmm. (the text says 0°5 to 2 mm.)
and height=0-8 mm. (the text says 0°33 to 1mm.). Ratio of
height to diameter =0-28 (the text would make it 0°6 to 0°5).
The lumen is said to be ‘small,’ but as,drawn has a diameter of
0:35 mm. No other characters of the joint-face are either figured
or described, although the drawing suggests that the side-faces
were transversely ridged. This feature and the general outline
distinguish I. smithi from J. trechmannt.

Tsocrinus californicus, from the Upper Trias, is represented by
well-preserved columnals. The section as drawn is a rounded star,
with a diameter =3°75 mm. (the text says 2 to 5mm.) ; height =
nearly 0°8 mm. (the text says 0°5 to 1lmm.). Ratio of height
to diameter =from about 0°25 to 0-2. The lumen is said to be
‘large and well-marked,’ but as drawn has a diameter of 0-14 mm.,
which (as Cui paves. with J. smithi) would be even minute. The
petals are ‘narrow’ and ‘sharply terminated’; from the drawing
it appears that the ridges are short and not confluent at the peri-
phery, but the side-view shows no trace of crenelle, which is.
curious. The side-faces appear from both drawing and photograph
to be gently convex at the IR angles and sharply so at the
reéntrant 7 angles, so that in the angle the sides are transversely
ridged. The photograph shows rather clearly a cirral, with section
circular, joint-face rimmed, central area raised, lumen minute.
The scalariform sides of L. californicus are enough to distinguish
it from IL. trechmanni, whatever its other characters may really
be.

The third species is a form recorded in 1877 by Hall & Whit-
field! from limestone of Middle Triassic age in Nevada. They
referred it with doubt to the Jurassic Pentacrinus asteriscus
Meek & Hayden. That, however, appears to be a Pentacrinus
sensu stricto, whereas the Triassic species is rightly referred by
Prof. Clark to Lsocrinus. Unfortunately, he neither deseribes nor
names it. The specimen is said by him, as former ly by Whitfield
in his ‘List of Types,’ to be in the U.S. National Museum ; but
Dr. Bassler, who has kindly searched, tells me that 1t caenee now
be found. The original figure, however, is ee clear enough to
serve as the basis of a diagnosis and a name. ‘The following are
therefore submitted :—

IsOCRINUS ARGENTEUS, sp. nov. ‘Transverse section a slightly
rounded star. Joint-face with radial triangle; lumen relatively
large and quinquelobate with radial lobes; petals lanceolate, but
not narrow; radial ridge-groups about 3, remainder of ridges about
15, but of these only 2 or 3 at the distal end of the petal reach
the periphery. Diameter, may ‘exceed one-fourth of an inch’
(say 7 mm.).
~ Holotype.—The specimen figured as Pentacrinites asteriscus ?

by Hall & Whitfield, 1877

1 U.S. Geol. Explor. 40th Parall., Final Rep. vol. iv, p. 280 & pl. vi, fig. 16.

part 3] CRINOIDS FROM NEW ZEALAND. 255

[I am indebted to the Director of the United States Geological
Survey for several sets of squeezes taken from the best specimens
found in Alaska (G. C. Martin, 1916). It is inferred from these
squeezes that the original specimens are in their natural relief.
Plaster casts have therefore been taken from the squeezes in the
Geological Department of the British Museum, and form the basis
of the following descriptions :—

JSOCRINUS CUPREUS, sp. nov. (Fig. 14, p. 248.)

Transverse section a rounded star, with the sides of the inter-
radial angles slightly convex. Normal joint-face with lumen
minute (under 0°25 mm.) and central area raised in a rim round it;
petals broadly lanceolate, floors flush with the ridges or but slightly
lower; radial ridge-groups about 4, their crenelle inosculating,
and apparently fragile, merging into peripheral crenellze, which
are 8 or 9, non-confluent. Suture crenelate all round.

Approximate measurements :—IR = 25 mm.; r=1°5 mm.;
reentrant angle=0°5 mm. ; making diameter =4°5 mm.

Locality.—Jumbo Creek, near Bonanza Mine, Copper River
region, Alaska. U.S. Geol. Surv. Loc. 4809.

Horizon.—Upper Trias, Chitistone Limestone, supposed to be
Middle or Upper Carnic, therefore comparable with Raiblian (see
G. C. Martin, 1916, p. 692).

Material.—Squeezes in various substances from specimens in
the collection of the U.S. Geological Survey, and plaster casts
taken therefrom in the British Museum, Geological Department.
Registered E 21915-21918, E 22178-22180.

Poloupe.-— Plaster cast EH 22178 and its original at
Washington.

Relations.—The most striking feature in the fossils (as inter-
preted from the squeezes) is the hollow that in nearly every radius
of every specimen occupies the position of the radial ridge-groups.
At first, this suggests a radial triangle; but closer inspection shows
that crenelle exist all round the periphery, and in rare cases, as in
the right upper radius of fig. 14, the radial ridge-groups still
remain. It appears as though these structures were of looser
texture than usual, and so were easily worn or broken away, leaving
as a rule obscure traces or even a mere hollow, as in the left upper
radius of fig. 14. This last appearance seems (on the evidence of
the squeezes) to be the most characteristic, and though it is not
in the strict zoological sense a diagnostic character, it may be
regarded as distinguishing what Prot. A. Se Wi ages (October
1917) has ealled a ‘metamorphic species.’! The visible character
of such a species is directly due to certain physical, mechanical, or
chemical conditions of fossilization or metamorphism ; but for it to
have any systematic value, it must be indirectly due to some
feature in the gross or minute anatomy. That feature may have
been invisible until made visible by the extraneous forces, which
act as do the differentiating reagents of the laborator y.

1 + Nuculites from the Silurian, &c.’ Proc. U.S. Nat. Mus. vol. liv, pp. 27-58:

256 TRIASSIC CRINOIDS FROM NEW ZEALAND. _ [vol. Ixxi.

Apart from this peculiar character, the species differs from other
known Triassic species. Those which resemble it in the crenelation
of the suture and in the absence of a radial triangle have petal-
floors depressed, and not flush as here. In JL. trechmanni, which
has flush petal-floors, the peripheral crenellee are fewer and are
generally confluent.

ISOCRINUS GRAVINA®, sp. nov. (Fig. 15, p. 248.)

Transverse section a slightly excavate star with rounded angles.
Normal joint-face with lumen small (obscure, say 0°5 mm.);
central area merging into adradial crenelie; petals narrow (4°4mm.
long, 1:6 mm. at greatest width, giving ratio of 0°36), their floors
depressed, with a greatest width approximately one-third of the
width of the petal (actually 0°6 mm.); adradial crenelle, after the
obscurely formed adcentral crenelle, are about 10 on each side,
regularly corresponding, 0°5 mm. long; peripheral crenellz estimated
at 5 (the ends of petals are broken) ; a well-marked radial triangle
with surface rising gently towards the radius in its outer (acentral)
region.

Approximate measurements:—IR=49 mm.; 7=371 mm.;
reéntrant angle = 0°7 mm.; making diameter = 8-7 mm.

Locality.—Cove 8 miles north of Dall Head, Gravina Island
(S.E. Alaska).

Horizon.—Upper Trias, supposed to be Lower Norie (see
G. C. Martin, 1916, p. 700).

Material.—Squeezes in various substances from specimens in
the collection of the U.S. Geological Survey, and plaster casts.
taken therefrom in the British Museum, Geological Department.
Registered E 21918, E 22181-22182. An obscure squeeze,
E 21914, indicates that a more broadly petaloid Lsoer7nus occurs
in the southern arm of this cove.

Holotype. — Plaster cast, E 22181 and its original at
Washington.

Relations.—A very distinct form. In the large radial triangle
and narrow petals it approaches a true Pentacrinus much more
closely than does Lsocrinus argenteus, and, unlike that species, it
has no radial ridge-groups. |

A radial triangle is slightly developed in Lsocrinus propinquus
and is well marked in an undescribed Lsocrinus in Dr. Wanner’s
material from the Upper Trias of Timor. All these species are
thereby distinguished from J. trechmanni.

There seems no doubt, then, as to the specific independence of
these New Zealand fragments, and I can find no name more fitting
to be associated with them than that of their collector, who has
thrown so much light on the real and alleged Triassic deposits of

New Zealand.

[November 30th, 1918.

CONTENTS,

PAPERS READ.

Page
7. Dr. C. T. Trechmann on the Trias of New Zealand (Plates XVII-XXV) ... 165
8. Dr. F. A. Bather on Triassic Crinoids from New Zealand..............0... 00000: 24.7

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part 4] JURASSIC CHRONOLOGY : LIAS. _ 257

9. Jurassic CoHronoLtoey: I—Ltas. ByS.8.
(Read June 6th, 1917.)

[Puares XXVI-XXXI.]

CONTENTS. nap
bas \ eee ott
eminem WIE koe hes em re ne PE Se 2574 a Mused ©

Mmeemuaenrand WWrnibbIan ...... 06... oie etee dodo eee cee eee edoes 259 —
wo Sd! BLOB 2k Sat. rir ae? en nee eee 260
MURMURED eS cle sed ne PSone ea vn einae Cue ede negine dene nseemenes 262
Mel eciAt 7... ||... 2c e.c- oe een cennn ence onsen ieee eee 263
(2) Wessexian ............ A MPRA SA ode a Ree 266
(Sieaasayan .2..)........... Fh cha, rag aah rea i epee ee Sia ae 267
Oo GLEE EL ale Bilge Sas gn ee eee 268
1D ELDEC: .y ace ge ek ae 2 ee 269
ONE oii igo a. os Baden eed ponbnen aaah wits 271
(ayeayaman ........- NS Fh git he 0 5 od eh Mn ey hee Po 273
O01 CS ESUIUIN? a <2) 4 ils Acie oA a Se 275
Np arE rte SE P58 alae din Weis le dalee wen ee vetcceseent 275

Appendices :—
I. Zonal Sequence in the Lower Lias, by J.W.TutcHzeR. 278
II. Mayer-Eymar’s Stratigraphical Terms .................. 282
Ill. Paleontology.

OL) HERES OC (0500 AS Oe ee 284
Wa Weseripilons Of SPECIES ... 40/2... 062... ee ete ees 284
(eGrealocieal inferences... 2.0.9). 6.16.0, 0 eden lads. 307
(d) Synopsis and Index Details ........................ 315

(e) Concerning some of Wright’s figured Ammonites. 318

I. InTRODUCTION.

Durine the last few years! I have been engaged to examine a
series of ammonites and brachiopods—some thousands of speci-
mens—collected by the officers of the Geological Survey of Scotland
in the islands of the Inner Hebrides off the west coast of Scotland—
Mull, Skye, Raasay. As the thickness of these Oolite-Lias deposits
is very considerable and specimens are in many places numerous,
the faunal sequence is often observable to great advantage ; and, as
new faunal elements have been disclosed in some cases, the Oolite-
lias chronology requires a certain amount of elaboration and
revision. By the kind permission of the Director of the Geological
Survey I am allowed to give an abstract of certain results. These
data, when compared with those which have been gradually accu-
mulating about other districts, throw an interesting light on the
faunal sequence in certain strata, and, though admitting that all
suppositions are not yet proved, I venture to offer to the Society
an epitome of evidence and surmise with the idea of drawing the
attention of other workers to the particular points about which
further investigation is desirable.

i This paper was commenced in the winter of 1914-15.

Q. J. G.S. No. 292. Y

258 ji MR. 8. S. BUCKMAN ON . | [wold Isang

The classical paper on the Scottish area is that by J. W. Judd!
He proposed the terms ‘Scalpa Sandstone’ and ‘ Pabba Shales,’
and, though working under great difficulty, showed considerable
acumen in his zonal classification: he recognized the presence of
the zones of humphriesianum, murchisone, spinatus, margare-
tatus, tbex, jamesont, armatus, oxynotus, semicostatus, and
bucklandt.

A more elaborate faunal sequence is put forward at the present
day, as shown by various chronological lists which have been
published by the present writer. for instance :—

1898. ‘ Jurassic Time’ Q.J.G.S. vol. liv, p. 442.
1901. ‘ Hom. Brach.’ Proc. Cotteswold F. C. vol. xiii (4), App. II, p. 265. |
1910. ‘ Jurassic Strata’ Q.J.G.S. vol. lxvi, p. 86.
1910-13. ‘ Yorkshire Type Ammonites’ i, p. xvi; ii, p. x.
1915. ‘Pal. Class. Jur. Rocks’; ‘Geol. Whitby’ 2nd ed. Mem. Geol. Surv. |
1915, chap. v, p. 60.

The tables in the two last-named publications may be taken |
as a basis of reference. But the excellent results obtained by
Mr. W. D. Lang,? by most painstaking work on the Dorset Coast,
show that still further elaboration is required. The same is the
lesson taught by the Scottish deposits. I propose to illustrate |
and compare these results with each other, and with details from
intermediate areas.

The present paper is entitled ‘ ]—-Lias’ to indicate that it is the |
first of a proposed series, to be followed, I hope, by further papers |
on the Oolites so as to complete the Jurassic Chronology on the |
same lines. The present paper gives the information about the |
Lias by working downwards from younger to older deposits, because |
that presents the different sections of the strata in continuous orderly |
sequence. Strictly speaking, then, this series of papers should |
have commenced with the latest rocks of the Jurassic; but, as I
am not prepared with their details, the sequence in the papers and |
that in the series must remain at variance—a technical blemish.

One could wish that, for geological and other records, printing |
and reading were from the bottom of the page to the top, because |
then results could be placed in their due order of developmental
sequence.

For stratigraphicai information, paleontological material, and
generous assistance, [ am very greatly indebted to several kind
friends: for Scotland, to Dr. G. W. Lee and other officers of the
Geological Survey, Scotland; for Yorkshire, to Dr. F. L. Kitchin,
Mr. G. W. Lamplugh, Mr. G. Barrow, and other officers of the
Geological Survey, England; for the Midlands, to Mr. B. Thomp- |
son; tor Somerset and Gloucestershire, to Mr. J. W. Tutcher; for |
the Dorset Coast, to Mr. W. D. Lang; for varied information, to

1 <The Secondary Rocks of Scotland’ (West Coast), Q. J.G.S. vol. xxxiv |
(1878) p. 660.
2 Proc. Geol. Assoc. vol. xxv (1914) p. 293.

part 4] JURASSIC CHRONOLOGY: LIAS. 259

Dr. A. Morley Davies. To all I tender most grateful thanks.!
For the Yorkshire area and for the South-Western Counties I have
also had my own field experience—chiefly in the last-mentioned
area.

Part of the following pages may be regarded as an extension of
the principle applied with success to sundry brickyard exposures
along a line of country—the principle of unlike faunas. Different
contiguous exposures show faunas of partly or wholly unlike facies:
theretore their deposits are partly or wholly heterochronous—find
the sequence. In wider extension three are obviously other factors
for consideration—agency of deposition, difference of basin, con-
stituents of the fauna—like must be compared with like. But the
following pages show, it is hoped, that the method of work may be
extended and justified; and that it may answer both ways—tor, as
a proved sequence shows the meaning of dissimilar faunas, so dis-
similar faunas give reason tor expecting heterochronous deposition.

It is fairly evident that geologists have been using the principle
of dissimilar faunas in separating strata, without recognizing 1t—
much as M. Jourdain had written prose wighout knowing the fact.
But it is not proposed to pursue the matter further now—it
deserves a study to itself{—and perhaps a terminology !

Il. YEOvILIAN AND WHITBIAN.

The whole of the Yeovilian and a considerable part of the Whit-
bian are unrepresented by strata in the Scottish isles: a deposit,
about 75 feet thick in Raasay, which I term the Dun Caan Shales,
corresponding in date to the post-moore: part of the Bridport
Sands of South Dorset? (early Aalenian), rests non-sequentially on
the Raasay Ironstone, which is of the date of the lower part of the
Whitby Alum Shale—post-falezferum hemera. This non-sequence
represents a break of about 700 feet of strata on the evidence of
various English localities ® ; and may prove to be very much more
when Continental deposits come to be analysed with the same
detail.

The chronology of the Yeovilian and Whitbian has been already
rather fully particularized in the last two communications men-
tioned in the list of works on p. 258; but there is reason to suppose
a fuller faunal sequence in the former, and (as regards the latter)
it seems desirable, on the ground of paleontological unitormity,
to class as early Whitbian the bed or beds hitherto regarded as
latest Domerian, see Summary, pp. 275, 276.

The attention of investigators should be particularly directed
to the sequence of strata on the Whitbian—Domerian border-line—

1 To Mr. Tutcher my thanks are due for his careful photographic illustra-
tions to the Palzeontological Appendix.
SO; daG. 5. vol. Ixvi (1910) pp. 60, 61, 64.
3 Ibid. vol. lix (1908) p. 456; ‘Geol. Whitby’ 2nd ed. Mem. Geol. Surv.
1915, chap. v, p. 75.
¥2

260 MR. 8. S. BUCKMAN ON [ vol. lxxiii,

the post-spenatum pre-falciferum deposits. This was a time of
earth-movement and local non-sequences: the full succession—
perhaps more elaborate than that to be recorded in the Summary—
may possibly be made out by taking note of dissimilar faunas.

The strata of the Yeovilian, anil locally, even certain beds of
the Whitbian, have until comparatively recent times been classed
with the Inferior Oolite Series or as Passage Beds between Lias
and Oolite—the dividing-line between Lias and Oolites (or Lias and
Passage Beds) being roughly taken along the line of change from
clay to sand; but this has been found to. vary paleontologically by
several hemerz.! Such former association, however, suggests that
there may be a more suitable opportunity to discuss these strata in
a proposed later communication dealing with the faunal sequence

of the Lower Oolites.

III. Domertian.

The Scalpa Sandstone, about 240 feet thick, is in the main of
Domerian date; some of the base is earlier. There is no direct
evidence for the stratigraphical sequence, but the faunas of the
spinatum and margaritatus dates are present, with that of algovi-
anum indicated. There is. however, another remarkable fauna in
a: distinctive matrix: it yields Amaltheus levis (Quenstedt), in
some abundance, some massive Rhynchonellids and other brachi-
opods. The Amaltheus, a Wiirtemberg species, a very distinct
dwarf form, has not hitherto been found in English strata, if my
memory serves me truly; the massive Rhynchonellids® are quite
new to this country; the other brachiopods agree in the main
with Domerian species of Yorkshire.

It is suggested, on the principle of dissimilar faunas, that the.
Scalpa Sandstone shows a new faunal horizon—one post-margari-
tatus pre-spinatum—a deposit made during a hemera of Amaltheus
levis, well-developed and preserved in Raasay, possibly in part.
preserved in Yorkshire—it is to be looked for at the junction
of the above-mentioned zones—partly, if not entirely, absent from
the South of England; but to be found locally on the Continent,
possibly in some thickness.

However, with this addition the sequence of Domerian faunas.
is certainly not complete. This is well shown in a paper by M. J.
Monestier.2 The strata between the Charmouthian and the
spinatum horizon hitherto placed in the zones margaritatus—
algovianum (Oppel’s upper and lower margaritatus zones) are
separated out by him into three subzones, with, in some cases,
further division into upper and lower horizons.

1 «Monogr. Inf. Ool. Amm.’ (Pal. Soc.) 1890, p. 167.

2 Grandirhynchia, 8. Buckman, ‘Gen. Jur. Brach.’ 1914. Two species.
figured in ‘ Brach. Namyau Beds, Burma’ Pal. Ind. n.s. ii (2) 1917 (1918)
pl. xiii, figs. 5 & 6, and described on P- 228.

x “Zone & Amaltheus margaritatus’ Bull. Soc. Géol. France, ser. 4, vol. xiii

(1913) p. 5.

part 4] JURASSIC CHRONOLOGY : LIAS. 261

From his excellent paper I extract the following as a summary
of the sequence :—

TABLE I.—FAUNAL HORIZONS OF LOWER DOMERIAN.
(After J. Monestier.)

Upper horizon. ‘ Amaltheus gibbosa Quenstedt.’

Subzone c. : ‘ :
Lower horizon. ‘ Seguenziceras algovianum Oppel.’

Subzone b. ‘ Celoceras acanthoides Reynes’

Upper horizon. ‘ Hildoceras boscense Reynés.’

Subzone og : Pies :
} Lower horizon. ‘ Grammoceras fieldingi Reynés.’

Monestier (p. 11) gives Amaltheus levis as a constituent of his
subzonec. Perhaps this is due to local paucity of deposition, for the
evidence of Raasay, so far as it goes, is to the contrary ; A. levis
is from near the top of the Scalpa Sandstone, while the indication
of an algovianum fauna is near the base—some 200 feet lower.

Over a considerable part of England it is possible that all, or
nearly all, of Monestier’s horizons are not represented, the
Domerian beginning with the algovianuwm horizon, or even later
than that locally. On the Dorset Coast, however, these lower
strata may, perhaps, be found.

The thickness of the Domerian on the Dorset Coast exceeds,
according to Day’s evidence,! that of the Scottish deposits, and
very considerably. From the Three Tiers to the Marlstone of the
Junction Bed, inclusive, there are 364 feet.2 It is possible that
180 feet of this—the lower part—represents strata missing from the
Scottish deposits and from other English localities; for it is per-
missible to interpret Day’s record of Am. thowarsensis in the Shell
Bed (p. 291) as Seguenziceras aft. algovianum: this would give
about 180 feet from algovianum to spinatum inclusive, whick
compares well with about 200 feet of Scalpa Sandstone within the
same limits, leaving 180 feet below in which Monestier’s pre.
algovianum horizons may be sought—lI have seen something of a
boscense style with the matrix of the Dorset Coast.

Monestier quotes an dAmaltheus fauna through all his horizons,
and Day gives A. margaritatus through about 380 feet of strata
on the Dorset Coast. It is to be regretted that investigators have
too often placed all the species of Amaltheus under one name; fe
with careful discrimination much information might have been
gained as to their horizons, with great advantage to correlation
work. But this range of Amaltheus, followed by its allied genus
Paltopleuroceras, induces the reflection that the strata yielding
these Amaltheidz ought alone to be classed as Domerian—the age
of Amaltheids.

In certain cases, then, the division between Whitbian and

1 ¢Middle & Upper Lias of the Dorset Coast’ Q. J. G. S. vol. xix (1863)
pp. 283-85.

2 Amaltheus has been found some 2 feet below the lowest tier, W. D. Lang,
Prec. Geol. Assoc. vol. xxv (1914) p. 329.

3 Species of Amalthews are enumerated in ‘ Yorkshire Type Ammonites ’
1911, p. 25d; but this by no means exhausts the series.

262 MR. S. 8. BUCKMAN ON [ vol. Lxxany

Domerian would fall in the upper part of the Marlstone. The
highest layer of Marlstone on the Dorset Coast—the serrata bed !
with Harpoceratoid ammonites,” may, on the principle of dissimilar
faunas, be expected to be of different date from the Transition Bed
of the Midlands with Z’/toniceras and peculiar Dactyloids—a bed
of lithic condition similar to decomposed Marlstone. Removal of
these two horizons to Whitbian would certainly make for greater
zoological uniformity, see p. 276.

The following comparative table of Scottish and English
Domerian may be given.

TasBLe [].—DomMERIAN SEQUENCE.

Dates. Strata.
= ee
Hemere. Raasay.! YORKSHIRE.? CHELTENHAM IN. SomEeRsET.4 DorseEtT
District. Coast.
7. spinatum ...... x 3-11? On S. Base of
Junction Bed.
BG LUIS 6s Sees x (12-21) P
BangvODOS@ << 2-26 x 22-26 C. Margaritatus -
Bed +
4. algovianum ... x 27-34 Shell Bed +
3. «canthoides ...
DL ESCENSE Sia. te (Strata about
the 3 Tiers) P
VS UCLA INGE ..o oo oa

1 The Scalpa Sandstone.

2 The numersls refer to beds in ‘ Geol. Whitby’ op. cit. pp. 73, 74.

3 The algovianum tauna 1s not known from the Cheltenham district; but is
recorded by Wright from Oxfordshire—Chipping Norton.

+ Even the spinatum deposit is often missing.

5 See Day, loc. cit. and S. S. Buckman, op. cit. p. 66. Intermediate beds cannot
be placed on present evidence. A much fuller faunal sequence than is here recorded
between spinatum and algovianum seems quite likely.

[x Fauna present, position surmised. C.,S., Beds in known sequence. |

For a further illustration, see fig. A, p. 265, and for further details
the remarks on that page.

LV. CHARMOUTHIAN.

Some small portion of the lower. part of the Scalpa Sandstone
belongs to the Charmouthian; but its main mass is made up of the
Pabba Shales, 600 feet thick in Raasay, 700 feet in Skye. They
are richly ammonitiferous, especially in the lower 400 feet or so.

1 «Jurassic Strata’ Q.J.G.S. vol. Ixvi (1910) p. 65, bed 1.

2 The species figured by Wright, ‘Monogr. Lias Amm.’ (1884) pl. lxxxi,
figs. 4-6 as ‘ Harpoceras radians, Upper Lias Shale, Hast Brent Knoll, Somer-
set’ bears a label in Dr. Wright’s handwriting ‘Down Cliffs, Charmouth,’
and is from the top bed of the Marlstone of the Dorset Coast. It well re-
presents the forms here alluded to: they require to be worked out and named.
There is perhaps some connexion with Am. pseudoradians Reynes, ‘Géol. Pal.
Aveyron.’ 1868, pl. i [bis], fig. 4. Wright’s specimen is in the British
Museum (Natural History) No. C. 2200.

3 These thicknesses were communicated to me by Dr. Lee.

part 4] JURASSIC CHRONOLOGY: LIas. 263

representing the so-called zones of armatum-raricostatum, where
they disclose a quite unexpected sequence of events. Concerning
the upper part of the Charmouthian they do not give much infor-
mation; but here Mr. Lang’s detailed researches on the Dorset
Coast come in.

Owing to the number of faunal horizons disclosed by the English
and Scottish strata, 1t becomes necessary to divide the Cae
mouthian; and it is at once noticeable that in the upper part the
Ammonite families Liparoceratidze and Polymorphidz are domi-
nant, in the lower part the families Deroceratide and Hchiocera-
tide. But such division into two parts would leave the upper
portion unduly large, while division into three parts gives better
balanee. In the upper third the Liparoceratide are the dominant
feature with the Polymorphide subservient; in the middle third
the position is precisely the reverse; while in the ‘lower third the
Deroceratidze and Echioceratide keep alternating in their domina-
tion. Therefore it is proposed to divide the Charmouthian into
three ages, named respectively Hwiccian, Wessexian, and Raasayan.
These terms are governed as to their limits, not by stratigraphy,
but by faunal constituents; and there should be no necessity to
change them if future discoveries show the advisability of small
additions to, or subtractions from, the stratigraphical units now
respectively assigned to them.

Perhaps no author has proposed, and, in the light of present
knowledge, perhaps no author can propose stratigraphical or chrono-
logical terms with fixed limits: non-sequences and the progress of
paleontological discovery are against such results. Detailed in-
vestigation has often revealed that the upper and lower limits of a
given stratigraphical term used by the same author really vary
from area to area to the extent of the deposits made during several
hemerze in each case. ‘Then the limits require corresponding
adjustments; but to alter the names whenever small adjustments
are made would produce a confusing multiplicity of terms for
what is substantially the same thing. It is too much to expect
that limits can be exactly fixed, even on the basis of dominance of
certain Ammonite families: future discoveries may spring surprises
on us. It is unlikely that the remarkable sequence disclosed at
Raasay (Raasayan, p. 267) with the large adjustment which it
involves will be the only discovery of its kind.

(1) Hwiccian,

The lower scarp of the Cotteswolds and the outliers which stand
as sentinels along the valleys of Severn and Avon in the counties
of Gloucester and Worcester show some fine developments of
strata earlier than the Domerian. The Hwiccas,! whose country

1 «The Hwiccas ...the people of Gloucester, Worcester, and part of Warwick

. the old Diocese ot Worcester before Henry the Eighth formed the sees of
Gloucester and Bristol. The Bishops’ Dioceses are generally the best guides
to the boundaries of old principalities. —(E. A. Freeman, ‘Old English His-
tory ’ 3rd ed. 1873, p. 82.)

\
264 JURASSIC CHRONOLOGY : LIAS. vol. lxxiii. |
5

exhibits these deposits, may well give their name to the age—
Hwiccian: it is the age when the Liparoceratide were dominant |
and the Polymorphide subservient. The following Table UII |
gives an interpretation of the evidence in Scottish and English :

areas.
TasLE III].—Hwiccran: ScoTnanp AND ENGLAND.
Dates. Strata.
eee
Hemerz. Raasay. YoRKSHIRE.! GLoucestER- N. SomERSET.? DoRsEtT
SHIRE.” Coast.t
9. Oistoceras...... 3 130. t Oistoceras}
129.§ +bechei. |
a. hantleyt” ~..°.. 126. Involute }
Androgyn.
henleyi-type ;})
davei.
Fats 4 ee 125. davei. |
|
6. (3rd capricorn). Capricorns, 5
base of
Scalpa Sandst.
5. (2nd capricorn). 6 Capricorns,
Pilley,
Leckhampton.
4, latecosta <i Dudbridge. Radstock; 124.) Androg.
(1st capricorn). (Androg. (Androg. Bath. 128. eee |
maculatum, latecosta) (Evolute 122.) group.
Androg. Androg.)
heterogenes)
3. Beaniceras ... x7 Hewlett’s Road Slopes of 121. [ Beani-
(Beaniceras) (Yellow Lias) ; Dundry. ceras :|
Stow-on-Wold. (Beaniceras) Lipareceras.
(Beaniceras)
2. carinatum ...... Leckhampton ? 1206. [ Beanic.?] |
. Hucclecote ? Acanth.
(Stout Acanth.) carinatum ;
Ae. spp. > 3)
Liparoe.
1. cheltiense ...... X7 Charlton Kings; Radstock; 120a. Liparoc.

(Lip. hept- Dumbleton, etc. Dundry.
angulare) (L.cheltiense) (Lip. zietenti)

1 The numbers refer to beds in ‘Geol. Whitby’ 2nd ed. Mem. Geol. Surv. 1915,
p. 69; the strata are about 155 feet thick, Bed 7 being 35 feet.

2 Specimens collected by my father. and personal observations.

3 Mr. J. W. Tutcher’s information.

4 W.D. Lang, Proc. Geol. Assoc. vol. xxv (1914) p. 293; the numbers are these
of his beds. In regard to this and the following tables, my best thanks are due
to Mr. Lang for the great pains that he has taken to supply me with information,
sending MS. notes of later researches and submitting specimens—my identifications
are in square brackets. Since this paper was read he has published some of these
MS. notes—* The Ibex-Zone’ Proc. Geol. Assoc. vol. xxviii (1917) p. 31.

|< Fauna present, position surmised. |
a

Fig. A.— Diagram illustrating the faunal sequences in the Domerian-Hwiceran.

latzecosta

DORSET COAST

Uh

<<a

——ao

<1
j

NORTH SOMERSET

GLOUCESTERSHIRE

isa
=
iG
Y)
x
5

S :

jo)

iS)

&

ae

is

+
>
<
7)
gq
xq
%

The accompanying
diagram (fig. A) shows
the faunal sequences,
and non-sequences, In
the Domerian and
Hwiccian of the areas
under consideration.
No account is taken
of the thicknesses of
strata; it 1s only a
faunal record; but it
becomes a_ stratigra-
phical illustration of
the position of affairs
when the concluding
strata of the Domerian
were deposited.

The datum-line is
7 Domerian (spina-
twm) proved in all
areas.

The movement of
the Mendip axis of
North Somerset 1s
quite obvious. Its
influence apparently
extended to Glouces-

-tershire. On the Dor-

set Coast, though the
Domerian strata are
especially thick, there
are two more non-
sequences, due possibly
to moyement of the
Weymouth anticline.
The last of these, the
pre-spinatum one,
which presumably co-
ineides with the lack
of the levis zone of
Raasay, is particularly
interesting. ‘he base
of spinatum has Blue
Lias pebbles, the date
of which it would be
interesting to deter-
mine. If, as has been
supposed, the pebbles
are from early Dome-
rian beds,! which
happen to be about

PaO dG. Son Vol Lava
(1910) p. 82.

266 . MR. 8. 8S. BUCKMAN ON pol Sissi;

160 or 200 feet below, this indicates a movement of the Weymouth
anticline to about that extent in order to expose the bed to
denudation. But the pebbles may be very much earlier, and the
movement may have been considerably greater.

(2) Wessexian.

The name for this age is taken from the Old English kingdom
of Wessex, which embraced the South-West of England, though
its boundaries diminished and enlarged from time to time, varying
more than the boundaries of a stratigraphical term—yet, like a
generic title, it kept the same name. The Dorset Coast, Somerset,
and Gloucestershire, were all part of it at one time, and all this
area shows strata of the age. The Radstock district in Somerset
has the strata thinly developed, and therefore not lending themselves

TaBLE IV.—WESSEXIAN: SCOTLAND AND ENGLAND.

Dates. Strata.
a ae aan Ahan gee a cea
Hemere. Raasay.* YORKSHIRE.2 CHELTENHAM.® Rapstock.t DoRsEtT
Coast.®
10. valdani ...... P x R. = -119. Ac. valdani
group. |
Oe heel et: x x feo ae ee
(Tragophyl- (T. ibex R. 118 ¢. § esti group. |
loceras fauna fauna only) T. ibexr &
only) wechslert.
8. ellipticum ... 118b. Ac. ellipti- —
cum group.
Me. BRONIE i322 2. X U. bronni (118 a. U. bronni
+ tine-ribbed | forms [and fine-
U. jamesoni < ribbed Uptonia.|.
form 1156. U. bronni
(Wright). i forms.
6. Platypleuro- R. 8 x vee [Platypleur.].
ceras. 113. [ Platypleur. ?|
5. trivialis ...... 8 111. { Polym. tri-
vialis group. }
4. jamesoni ...... R 9 R
SB. PELCOS” eo56 ses 110? [C. pettos, C..
grenouillouai.|
2. peregrinus ... 108. [ Polym.
peregrinus ?
Haug |.6
Deroceratid.
1. Phricodoceras. 11 x R. 105. Phricodo-
J. Buckman Coll. ceras.

R. beds in position ; about 30 feet separates them.
See former Table. About 120 feet involved.

3 As in Table III (p. 264) and in Wright’s records.
™4 Asin former Table. R.=beds in known sequence; X =fauna present, position
surmised.

® See former Table.

6 Agoceras polymorphus Wright, pl. xl, figs. 1-8, cited by Haug as near to his
species.

woe

1

C6}

~T

ABLE V.—Raasayan: ScOTLAN

| Beds 13-16 with large

Bed 18. ‘The Upper Coney-

a ee ie a

YorxKsHIrE,? -Mipranps,3 {
about 85 feet. about 10 feet.

> ae
|

ae

Derocerates.

bearei bed’ with E#. apla-
natum.

Bed 20. Shale with Eehio-
ceras macdonnellii.

Absent.

4

iThe type of Am. miles
caine from Whitby. |

The type of Am. armatus
came from Whitby. ]

ed 23. Amm. of sub- | |
planicosta type. Dero- ‘ Armatus zone. A. den}y
ceras obsoletum (Blake) nodus (several spp.), -
_=Am. densinodus auctt. muticus, A. subpla
Deroceras nodoblongum. costa, common.’

ed 23.| ‘A. densinodus ‘ Raricostatus zone.
[obsoletus| is plentiful densinodus, A. rai
in a band about 2 feet costatus.’

Laboue [ A. raricostatus |’

‘Tate & Blake, p. 77-

|

to be published by the Geological Survey. The] i
Scottish Survey in ascending the Allt Fearns Valf}
Yorkshire Type Ammonites’ ii (1914) p. 96d.
urv. 1914, p. 70.

G. S. vol. lv (1899) p. 71.
and personal observations.

: , (1914) p. 321, and see remarks, Table III, footn

outh Wales Line’ Q. J. G.S. vol. lviii (1902) p. 7

| A

part 4 JURASSIC CHRONOLOGY : LIAS. 267

.

very rapidly to the detailed sequence now asked for; but the
deposits are very fossiliferous and especially ammonitiferous.

This is the age when the Polymorphide held chief position,
while the Liparoceratidie were inferior in importance.

Table IV (p. 266) gives the evidence in various areas. A pre-
sumed faunal repetition of Uptonia (jamesoni and bronni) seems
to be the only method of reconciling this evidence. Such faunal
repetition 1s, however. so much in accord with what Raasay shows
in lower beds (see Table V) that the solution seems quite possible.

_ Mx. Lang has also recorded faunal repetition in the case of series:

of Acanthopleuroceras in the Hwiccian and Wessexian of the

Dorset Coast, as this and the preceding table show.

(3) Raasayan.

The Seottish evidence in this case is excellent and most im-
portant. The result is to show that in the strata hitherto assigned

to the armatum-raricostatum zones the sequence is much more
complicated. There are :—

7. Upper Deroceras horizon.
6.
5. | Upper Echioceras horizons—three stages.
A.
3. Lower Deroceras horizon.
1,2. Subplanicosta and Lower Echioceras horizon—possibly two stages,.

possibly more, see p. 268.

The Scottish deposits show faunal repetition and faunal alterna-
tion of Hehioceras and Deroceras, thus giving the clue to the
correlation of the strata in other areas. The available evidence is
brought together in the accompanying Table V; more precise
fetils aos the lower horizons would be deenable. and further
investigation in Raasay may be expected to furnish them.

The great thickness of the Scottish strata—tfive, ten, and eighty
times as thick as the English deposits—is the chief factor in dis-
playing the sequence. Thus it will be seen that, between the
armatum zone of the Midlands and that of Radstock, hitherto
thought to be isochronous, the Scottish deposits exhibit a thickness
of some 300 feet of strata.

When the English strata are compared with the Scottish, it will
be noted that, although no one locality shows the full sequence, yet
all put together prove the Scottish sequence. Jt is evidently the
same on the Continent—the Rhone Basin, Freiburg Alps, Bavaria,
Wiirtemberg, Hierlatz, contain to some extent heterochronous
deposits with dissimilar faunas. Each area lacks something ; but,
when all are placed together, they are seen to supply one another’s
deficiencies, and to make up the sequence of Table V. Bavaria
lacks what Wiirtemberg has, and supplies in part what Wiirtem-
berg lacks; and so with the other Continental areas.

There is reason to suppose that at the beginning of the Raasayan
considerable earth-movement took place producing various local
non-sequences—a legacy from Deiran times (see p. 273 and

7. leckenhyi

6. aplanatum

5. macdonnellii...

4. raricostatoides. .<

3. bispinigerum

= 5
Tanne V.—Raasayan: Scornand AND Eyanann.
Strata
eee Yorxsurrn,? Mrpianps,® Somenser (Rapsrock),!
about 400 + feet. about 86 feet. about 10 feet. about 5 feet.
c |
“ The Gastropod Beds (the

J Beds on Hallaig shore with Beds 13-16 with large \armatus bed) with large

} large Derocerates. Derocerates, ‘Derocerates.

L =

Loc. 12, 13. Beds with Bed 18. ‘The Upper Coney- i)

3 carinati-sulcate Zchio- bearet bed’ with 2. apla-

il cerata. natum.

Loe. 10a-11. Beds with Bed 20. Shale with Hehio-
: | degenerate BWceh.vcerata ceras macdonnellii.

( Be ERED The faunas of these three
horizons are found in de-
rived condition in the
“armatus bed,’ [* with

| much phosphatic matter.
| \ ; Undisturbed portions of
| the beds are left at a few
| places—these consist of
Loc. 7-9, Beds with mainly r Ae ‘aa ah aa i,
J Loc. 7-9, ds Ww anly shales,—J. W.T.]},
crassicostate Wehiocerata.
|
is |
| (The type of Am. miles
came from Whitby. |
Loc. 4-6. Beds with Rhyn- /fThe type of Am. armatus é
4 chonellids, Deroceras an- came from Whitby.] No evidence at Radstock
quiforme and Deroceras for tithe bispinigerum
of the armatum type. fanna nor for the _ den-

! sinodus — subplanicosta *

\ J faunas, below. u
Soppoury, GLovucESTER-

2.8
(Loe. 3. Deroc. (Microc.) SUES
cf. densinodus (Wright).
Bed 23. Amm. of sub-
planicosta type, Dero- ‘Armatus zone. A.densi- ‘Thin shale with a few

2. subplanicosta
(densinodus).

1. 1st Eechioceras.

+ Loe. 2. Deroc. (Mieroc.)

2,
afl. olsoletum (Blake),
Bifericeras subplani-
costa?, B. witreum?

(Simpson).
S

~ Loc. 1. Deroceras obso-

| letum, Wehiocerata.

ceras obsoletum (Blake)
=<Am. densinodus auctt.
Deroceras nodoblongum.

[Bed 23.| ‘4, densinodus
[obsoletus) is plentiful
m a band about 2 feet
above [ 4. raricostatus)*

Tate & Blake, p. 77-

ee a

nodus (several spp.), A.
muticus, A, subplani-
costa, common,’

“ Raricostatus zone, A.
densinodus, A, yapj-
costatus.’ |

1 Puller details will be given in a report fo be published }.
were made by the geologists of the Scottish Survey
about 300 feet of strata, Sce also ‘ Yorkshire Ty

* Geol. Whitby’ 2nd ed. Me

3 B. Thompson, ‘Geol. G. C. Ry.

4 Information from Mr,

® W.D. Lang, Proc, Geol. Assoc. v

5S. H. Reynolds & A. Vaughan,

J. W. Tutcher and

y the Geological Sur:
in ascending the Allt
pe Ammonites ”
m. Geol. Sury. 1918, p. 70.

QJ, G.S. vol. ly (1899) p. 71,
personal observations.
ol. xxv (1914) p, 321, and se

e vemarks,
‘Jur, South Wales Line’ Q.

limestone bands 30 feet.
Am, densinodus ?”

*Pyritous limestone and
shale 2 feet. Amm. att.
armatus, Amm. raricos-
tatus.”

4

Dorset Coast,*
about 45 feet.
(‘Bed 105. Armatus Lime-
| stone, Deroceras pugnax?
S. Buckin., D.aff. leckenbyi”
[D. leckenbyi (Wright)
pl. xxx, figs. 1-3].-
“Bed 104 Armatus Clay.”
* Bed 103. Hummocky Lime-
stone.’ [ D, aff. Jorioli Hug

+ sp.]

[No evidence for these two
faunas and no yvoom for
them. }

c

Bed 102. [Crassicostate
Exchioveras.|
“Bed 100.” [e. Z. ef. boreale.
[b. 7. like above, but more
strongly costate. |
{a. B. cf. rhodanicun, EB.
gracile, B. costidomus.}

“Bed 99. Watch Amm. Stone’
(2B. microdiscus anda crassi-
costate species |.

“Bed 98° (2. cf. costidomus
(crushed) }.

¢ Bed 96 [b]. 11’ below bed
99.’ [ Deroceras miles. }
| ‘[a] 12-14 below 99°
| Deroceras armatum).

“Bed 94. 15’ below 99’
| Deroc.bispinigerumsp.nov.
Sve Palewont. App. p. 302).

* Bed 93’ [Ammonites of den-
sinodus wid subplanicosta
types. |

‘Bed 92. Oaynotus Bed *
Am. obsoletus Blake (non
impson) sp.]. _ * Pyritized

Oxynoticeras ’ [?devived }.

t Fearns
1 (1914) p.o6a,
1

note 4 (p. 264).

vey. The ‘Loc, 1-13’ are places from which collections
Valley, and they show the faunal sequence through

a

268 MR. 8. 8S. BUCKMAN ON [ vol. Ixxiu,

fig. B, p. 272). As a consequence it may be expected that the
faunal sequence in early Raasayan was more complicated than
that shown in Table V. The Sodbury evidence. gives the asso-
ciation of ‘Am. aff. armatus’ and ‘A. raricostatus’ [an armatoid
and an Hehioceras| below the densinodus | obsoletum ?| horizon.
The Midlands, according to Mr. Thompson’s evidence, show the
second at a lower horizon than various armatoids which he asso-
ciates with Am. subplanicosta. Cheltenham has a very definite
subplanicosta horizon, and it is below this that various armatoids
occur. A consideration of these points suggests that, instead of
the two horizons of the Table, there may be three if not four in
the following descending order :—

(d) subplanicosta.

(c) obsoletum (densinodum).

(b) armatoids.

(a) Echiocerates. ;

Attention to this point would be desirable. Ammonites are
abundant, but small. They have not yet been examined in a
sufficiently critical manner—a very long task; in many cases their
identification with already named species is open to much doubt.
The faunal repetition in the Raasayan begins to make many

things clearer. For instance, it is now possible to understand the
absence of lar ge armati from the Midlands ; and the very remark-
able number of species of Hcehioceras. 'The list in ¢ Yorkshire Type
Ammonites’ (p. 96c, 1914:) enumerates 44 species, and is by no
means exhaustive. As the product of development at intervals
during a very long period of time, they are much more under-
standable than as the product of one date; and, as the outcome of
repetitive series evolving on parallel lines, the frequent similarity
but not identity in the Echiocerata is explicable.

V. SINEMURIAN.

The Scottish deposits are not rich in Ammonites; but there is
evidence for the sequence of certain faunas, while loose blocks
on the Hallaig shore of Raasay indicate the presence of others.
The evidence is instructive when compared with that of English
localities, especially with the detailed work done by Mr. Lang on
the Dorset Coast.

The great increase which the Scottish deposits have proved in
the faunal phases of the Raasayan might have been anticipated
from. other localities, if strict attention had been paid to dissimilar
faunas. Now, in the Sinemurian, the case may, perhaps, be
reversed: by paying attention to faunal dissimilarities it is hoped
to anticipate that full faunal sequence which may some day be
proved in a thick deposit.

With increase of horizons the need for division of the Sine-
murian seems to be great. It has been felt already. Choffat has
divided it into Upper, Middle, and Lower Sinemurian,! and this

1 «T’Infralias & le Sinémurien du Portugal” Comm. Sery. Geol. Port. v
(1903) pp. 54-106.

part 4) JURASSIC CHRONOLOGY: LIAS. 269:

seems to fit the tmonute development more satisfactorily than a
division into two parts. Here it is proposed to adopt something
of the same divisions, styling them Deiran, Mercian, and Lymian.

(1) Deiran.

This is the age when the gerontic phase of the Arietidze was in
full development: it is the period of the oxycone Arietids. Its
strata are perhaps more developed in Yorkshire than in other
English areas; and it takes its name from Deira, the ancient
kingdom of which Yorkshire formed a considerable part.

The sequence of faunal horizons is suggested in the following
table.

TaBLE VI.—DEIRAN.

Dates. Strata.
ee
Hemere. Tere YORKSHIRE.!| CHELTENHAM SOMERSET. DORSET
DistRicr. Coast.
8. (lymense)? ... Oe)
7. Radstockiceras? Radstock, north
ot Mendips.
6. Gleviceras? ... Folly Lane, (x)

Cheltenham
(lower part).
1p Vale of Glou-
cester. X
Lansdown,
Cheltenham.

5. polyophyllum .

4. oxynotum ......

So. bifeyune......5.: Aston Cross, Canards
Tewkesbury. Grave, south
x ot Mendips.

2. simpson ...... 2

No details nor fauna at present.

1. Gagaticeras... 3

1 ‘Geol. Whitby ’ 2nd ed. Mem. Geol. Surv. 1915, p. 67.

2 See Appendix III, Paleontology, pp. 287, 289.

tie Fauna present, position surmised. (X) Fauna present, supposed to be derived
and redeposited in Raasayan (Table V, Bed 92): Mr. Lang, however, suggests
paucity of sediment. |

The Deiran seems to have been a time of much earth-movement.
and consequent non-sequences, with the result that there is little
correspondence of fauna in different English areas. This means
that the sequence given is based mainly on supposition.!

The certain evidence is the sequence Gagaticeras—simpsont
in Yorkshire with polyophyl/um. presumably later; the sequence
oxynotum—Gleviceras in Gloucestershire with bifer um, it 1s
reasonably certain, earlher than oxynotum. There is no definite
correspondence here to work upon, and other areas give no help as
they show other dissimilar faunas.

It is here suggested that the Yorkshire Gagaticeras—simpsoni
strata are earlier than the Gloucestershire deposits.

The position in the faunal sequence of the polyophyllwm horizon.

' See further remarks in Appendix III, Paleontology, p. 310.

270 MR. 8. S. BUCKMAN ON [vol. Ixxiii, |

(Oxynoticeras polyophyllum Simpson sp., ‘Yorkshire Type Am-_
monites’ 1909, No. 8) may be worked out on theoretical grounds.
If it were placed immediately above s¢mpsonz, then the Yorkshire |
strata would be in sequence; but the biological features of |
O. polyophyllum seem certainly to suggest that it is a derivative —
of O. oxynotum with a suture-line of the same pattern, but
details somewhat more elaborated, and with ribbing greatly in-
tensified (venewed costation). In that case it should occur later
than O. oxynotum, and, as there is no stratigraphical evidence to
go upon, it seems advisable to work upon the basis of the bio-
logical interpretation. This, however, involves a theory of a non-
sequence in the Yorkshire Deiran deposits, and the multiplication
of non-sequences is inadvisable unless there be some evidence.

The sequence thus suggested for the noticeably dissimilar oxycone
faunas of the different areas makes Yorkshire to show early Deiran
deposits with a middle Deiran fauna separated by a_ break;
Gloucestershire, to which the Midlands may be joined, to show
middle Deiran faunas with, perhaps, a break in some localities due
to removal in places of deposits of polyophyllum date: this would
account for local appearances and absences of the species in this.
area; Somerset north of the Mendips to show late Deiran fauna,
with little deposit and certainly a good deal of redeposition.
Dorset shares with Gloucestershire an oxycone fauna of G/eviceras
date; but its special form, O. lymense, is not found in the other
British areas, so far as I am aware. Both these forms are pre-
‘sumably derived and redeposited in Raasayan strata; for, if
O. lymense were indigenous in Bed 92, it ought to have been found
in the Raasayan deposits of other areas. ‘The supposition, then, is
that a dymense horizon is the latest phase of Deiran.

Much support for the general conclusions here advanced about
the dissimilar faunas of the Deiran horizons may be found in
Continental works: the Rhone Basin (Dumortier) shows only
ammonites of the horizons Gagaticeras, Gleviceras, and Rad-
stockiceras—those of the other horizons are lacking, for the
examples figured as A. oxynotus by Dumortier are species of about
the Gag gaticer as horizon; Wiirtemberg (Swabia, Quenstedt) shows
the oxynotum and biferum faunas certainly, doubtfully the Glew:-
ceras fauna, but no fauna of the others.

Thus Gloucestershire and the Midlands are to be bracketed with
Wiirtemberg so far as the oxynotuim fauna is concerned, and
are separable from other English areas; Radstock, with its varied
and remarkable oxynotes, agrees with the Rhone Basin; it shows
special forms uot yet found in other British areas ane Rad-
stockiceras fauna. Yorkshire shows many oxycones which seem
to be peculiar to itself: it has little agr eement with other English
areas or with Wiirtemberg, but rather more with the Rhone
Basin—not, however, on the same basis as Radstock.

Lastly, Dorset shares with Gloucestershire a little, but has
O. lymense to itself. (For further remarks see fig. B, p. 272, and |

also p. 273.)

part 4] JURASSIC CHRONOLOGY: LIAS. 271

(2) Mercian.

The strata of this date are well developed in Gloucestershire
and the Midlands—mainly the ancient kingdom of Mercia. The
Mercian corresponds to the catagenetic phases of the Anietidie
(post-tuberculate Asteroceras and incoiling phases of Arietites).
In middle Mercian is a phase of degenerate Arietids which have
lost keel and furrows—usually called degenerate Asterocerates.
The fauna is very prominent in Yorkshire, and is found in Ireland
and in Wiirtemberg. It is not, however, known from other British
localities, with the exception of Pershore (Worcestershire); but the
special Pershore degenerate is a species not known from the other
localities. On the principle of dissimilar faunas it is reasonable to
expect one, if not two, horizons in middle Mercian somewhat later
than obtusum. ~

In early Mercian the Barrow-Gurney fauna has its own pecu-
liarities, possibly indicating another horizon. But this cannot be
discussed without a Baodeeron of the Ammonites; so it must
be relegated to the Palzontological Appendix, see p. 311.

In regard to Arvetites turnert, Mr. Tutcher is of opinion that
it precedes birchz,' and this would seem to be the position assigned
to it by Tate & Blake. It is true that the name A. ¢urnerz has
been very much misused, and that in a pre-berchi position there
are, as I have reason to think, forms allied to Arnioceras with
somewhat of an Arzetites aspect which possibly require separation
as a new genus from both. But an explanation on these lines
does not satisfy me, where Mr. Tutcher is concerned; faunal
repetition on the lines of Echioceras of the Raasayan may be
more likely. It is evident that a prolonged stratigraphical and
paleontological investigation is required to solve the problem.

The following table gives the evidence of faunal distribution
and sequence in the Mercian.

TaBLeE VII.—MeErcran: ScoTLAND AND ENGLAND.

Dates. Strata.
Hemere. Raasay. YORKSHIRE.! Gan eae BRISTOL DoRSET

Disrrret.2 District? Coast.
7. denotatus ...... 4, X Creltenham. 3
‘6. stellare ......... XCheltenham. Radstock. 88
5. planicosta...... 9 Radstock. 85-87
4. sagittarium ... 10 X Pershore.
3. obtusum......... 10 < Bredon. Radstock. 83, 84
ae OPOOK 10... ... R. 78-82
1. turnert ......... R. X Bredon. xX Barrow (ETE

Gurney.
1 Geol. Whitby ’ op. jam cit. p. 67. 2 As in previous Tables.

1 See Appendix I, p. 280.

Nvulad | a
Oo

—umyypAydosjod _
Ss

UY
7 ,

ISSOMIAZAAS

NVAVSVVad

SANVICIW GNV
AYIHSYALSHONOTD

se
Yj Gia |
Lace

SS

Z

SS
ES
SS
SS

|
é SOPOILIY
é Panne LIU Ly

4

HaUlLHSAYOA AVSVVY

UW)Idba un ‘unsiagy ‘uohnvspnay ay, ur saauanbas youn, ayn buraparsnj)r woshor17— a *S1
ji ; if IY} IUIZVA}SN]] | ty

part 4] JURASSIC CHRONOLOGY: LIAS. 273

The accompanying diagram (fig. B, p. 272) shows the various
earth-movements and denudations which took place during
Raasayan and Deiran times, producing many non-sequences. It
is constructed on the same principle as the previous diagram
(fig. A, p. 265).

The datum-line is 1 Wessexian (Phricodoceras), proved in all
areas except the Scottish one. Again the continuous movement of
the Mendip axis is very noticeable ; for, although there are several
Raasayan faunas present in North Somerset, yet they are derived
almost entirely, shown in the table by bracketing them with
7 Raasayan.

During Deiran times the movements were of several dates
not always isochronous in the different areas—hence the frag-
mentary nature of the deposits and their lack of corre-
spondence. One movement produced obliteration of the early
Deiran deposits in Gloucestershire and the Midlands, another the
obliteration of the latest deposits. Yorkshire would seem not to
have suffered from the first movement, but it did from the last;
and, it the position of polyophyllwm in the sequence be correct,
another movement of about middle Deiran time must be postu-
lated: there are traces presumably of a slightly later movement—
local obliteration of polyophyllum-—in Gloucestershire. In North
Somerset the first and second movements seem to have had full
sway and to have effected complete obliteration, but there was a
pause to allow the deposition of 7 Deiran, though the strata then
laid down suffered considerably by the latest Deiran movement
which continued, with perhaps occasional slight pauses, well into
Raasayan times. On the Dorset Coast there would seem to have
been continuous movement and penecontemporaneous erosion ;
at least the result, as I judge it, is that no Deiran deposits were
left: there was denudation down to 6 Mercian, but the fossils of
some of the later Deiran strata—laid down during short pauses—

were swept together and redeposited in early Raasayan.

(3) Lymian.

The strata of this age are well-known and well-developed at
Lyme Regis, from which the name may be suitably taken; but, so
far as present records allow of interpretation, it seems that they
are not complete there. The Lymian is the time of anagenetic
and tubereulate Arietids.

The difficulty of ascertaining the number and sequence of
horizons in the Lymian is due to the wholly uncritical use of names
like Ammonites bucklandi. Instead of being a common and
universally distributed species as records make out, A. bucklandi
is a special massive form which I can only be certain of from
Keynsham.! I suspect the occurrence of another horizon with a
fauna of smaller Coronicerates, but whether pre- or post-bucklandi
has yet to be determined: the placing of it as post-bwcklandi is a
surmise.

1 See Paleontological Appendix, p. 302.

Ora, G. S.No. 292. Z

Dates. Strata.
——-, ee A >)
Hemere. Raasay. YORKSHIRE.! GLOUCESTER- BRISTOL DoRsET
SHIRE,“ ETC. District. CoastT.*
Be POUT CNDn kre x X Bredon, W. X Horfield. 75
7. Arnioceras R. Up. Buck- < Radstock. 50-72
landi [6].
6. Agassiceras ... R. eee xX Bredon, W. Keynsham. 49 P
Mid. Buckl.
5. gmuendense ... x X Berkeley, W. Keynsham.
Mon. pl. iv.
4. vercingetorix . Low. Buckl. XFretherne, W. (40-47) ?
[e]. Mon. pl. iu.
3. bucklandi ...... Keynsham.
(26-29) 2
DZ POCALOn aan Keynsham. xX Wright,
Mon. pl. v, f. 4.
1. Vermiceras ... R. Low. Buckl. ee 21
[a]. Top Sodbury.
angulatus.

274: MR. 8. 8S. BUCKMAN ON [vol. lxxiii,

Mr. Tutcher takes strong exception to the use of Arnioceras
to indicate a horizon, because it has too wide an extension,
ranging, he says, through most of the strata here placed as
Lymian. But the Dorset evidence shows Arnioceras dominant in
a particular set of beds; and, although this may be striking because
of the absence of certain preceding strata, yet it is sufficient for
the present: there is a post-Agassiceras horizon with Arnioceras
shown at Raasay, and a pre-birchi horizon with Arnioceras in
Dorset. A more suitable name for this faunal horizon must wait
until the many species of the genus are better known. It is quite
possible that here again may be faunal repetition.

The following table gives the evidence of the various areas :—

TaBLE VIII.—Lymian: ScottanD AND ENGLAND.

1 See R. Tate & J. F. Blake, ‘ Yorkshire Lias’ 1876, pp. 58-62, suggested inter-

pretation.
2 W., Wright’s records in his ‘ Monograph of the Lias Ammonites’ (Pal. Soc.).

3 Mr, Tutcher’s information, and a summary of MS. sections which he has most

kindly allowed me to use.
4 My interpretation of Mr. Lang’s records, Proc. Geol. Assov. vol. xxv (1914)

pp. 310 et segq., and one of Wright’s records.
[R. Strata in relative position. X In all cases, fauna present, position surmised. ]

The faunal sequence below the Sinemurian (Lymian) I leave in
the most capable hands of Mr. Tutcher, who has kindly contributed
what is placed as Appendix I, p. 278. He has also given his
reading of the lower part of the Sinemurian sequence, as he has
observed it in the Bristol district: this, too, I am pleased to record.
There are differences in our two accounts; but, as they are records
of original observation and research, not statements for a text-
book, there is no need to strive for uniformity. Several differences
are merely details: he uses trivial names where I employ generic.

part 4] JURASSIC CHRONOLOGY: LIAS. 275

There are two main differences: one, his placing of twrneri, upon
which I have already commented (p. 271); the other, his placing,

on the evidence of local deposits, a scipiontanum zone between
Agassiceras (sauzeanum) and gmuendense; this I am quite pre-
pared to accept. The omission of the vercingetorix horizon was
expected: the area under Mr. Tutcher’s observation lacks the
fauna, so far as my knowledge goes.

With regard to our use of the term turneri zone, it has been
objected that this term should be employed in the sense and for
the strata to which it was originally applied by Wright. This
dictum I traverse. I would argue that the zone of tuwrneri is
determined not by the author, but by the fossil. The zone of
turnert is the deposit made while A. turneri was in existence:
it is the deposit of the hemera twrnerz. If a writer misidentifies
A. turnert, he misnames its deposit twrneri zone. If a future
historian identified Queen Elizabeth as Queen Victoria, and called
the Elizabethan Period the Victorian Age, he would not thereby
make it so and shackle future writers. The Victorian Age was
determined by the time when Queen Victoria lived; and the turnerz
hemera, and the deposit made then—the zone—must likewise be
determined by the time when A. twrneri lived.

As to who is right or wrong in the determination of
Ammonites turnert Lam not yet prepared to argue.

VI. Summary.

The various horizons of the Ages dealt with in this paper may
now be brought together in sequence; and a table (Table IX,
pp. 276-77) may ber, given of certain notable areas of Great Bean
and the Continent, recording the presence of the faunal horizons
in Scotland, the North and South of England, the Rhone Basin
(Dumortier), and Wiirtemberg (Swabia, Quenstedt). The results
are interesting, and they suggest that a more extended analysis on
these lines might yield some rather striking information. Such
analysis may, perhaps, be attempted at some ater date.

VII. ConcLusion:

This is a sketch, much of it theoretical. Its main purpose is to
be a basis for further work, indicating the details and evidence
which investigators should look for. Much research is yet neces-
sary to obtain perhaps even an accurate sequence; for it is not
claimed that all the sequences are proved: they are offered as
interpretations of the present available evidence.

One lesson which may, perhaps, be learnt from this study i is that
great indeed as is the advantage of collecting specimens 77 situ,
yet it is not absolutely essential: in some cases, owing to paucity
of sediment and to derivation of specimens, it may even lead to
erroneous conclusions. As collecting 7m sztw is very often quite
impracticable, it may be well to remember that much can be done
without it, provided specimens are properly localized. For the

Z2

276

MR. S. S. BUCKMAN ON

TaBLe 1X.—GEOGRAPHICAL DIsTRIBUTION.

(vol. Ixxiu,

¥aunal Horizons.

F

YEOVILIAN. |

9
8.
he
Age of 6.
Dumortierians < 5.
and 4.
Grammoceratids. zy
2.
1
iLit
10
W HITBIAN.?
Age ot
Dactyloids
and

Harpoceratids.

DOMERIAN.
Age of
Amaltheids.
See p. 260.

HwiccIan.
Age of
Liparoceratide.
See p. 263.

e

Ge ee ee ee

WESSEXIAN.
Age of
Polymorphide.
See p. 266.

RAASAYAN,.
Age of
Deroceratide
and
Echioceratide.
See p. 267.

ey Se gee De) Ge SS
le TS ee aa eo a eae ee er a Ge

- ewbcorinat

L PSCUdOUAtUM %.. % .widasu2s-Peeaes oe
» SJ OLET CPU bw. caha teat cty a eee
. evaratum, :

. tenuicostatum

. acutum

. gibbosa
. algovianuin BF Mh Seta RES Re
5 IL COMLNOUR OSPR 8s 03% «eee eee

WRADNre woe bo MN we

. subplanicosta (densinodum) .
. Ast Hehioceras ........0... eee eee

. moore: .

Giiulloceras! 1 :
(Dunmortienta ent he
Hammatoceras?

DES PAMSUAM, Wiens dvsioge sos sae agactacnlaa
S ETUC TAMIL Me sene eeke nee eee ee
pedicum .. a

CSEPU A Ae CO) Ae ee ee
SEPIATULIUM ee ee as eee

ED DATtA Oise Satsnas ete eee
WAT GUNA eSB ees ce ee
. fibulatum

Hild. bifrons fauna
Frechiella subcari-
nata*

eee Ces ewe cee cee

Harpocer atoid —
spinatum
levis

boscense*
. fieldingi®
Oistoceras
‘henleyi’
davwet .........
(3rd capricor 1)
(2nd capricorn)
latecosta (1st capricorn)
Beaniceras PE ies
carinatum
cheltiense

"VO and Cite eee i eee

LAL ieee eae Pte I ey Pe Pe
CLUDDEL CONIA, oo cus sc apatnecine samc
bronni .. Se ts pears

Pie eardcapae oh a cn 8 ha:
CP UOUAVIS oe aa ie Bilas Aer ae eee
GOMES OIE Sa a. see ke Pity a2 Se
MOTOS: rcmeuc octet ass cate eer ee ee
peregrinum bogus Hac ch Bsaeaos cbr
TP HITCONOCCRUS cn Rad kaa
LECH CMON IE i yudone eke oae eae
UPlLanalin. (oe. Aa ee ees
MLMCMONMELLEI He. Sa st eS Babee
raricostatoides ....

bispinigerum ......

xX XX:

KKK KK KK:

<a
=
Sh |e =
Mm | a
na
g)4
LS Ales.
= |
x
x
x

ee“ XK eX:

OK Ryd pK OR OR Pek

KKK ie ORK 8

XX re:

KK RK HK KK OE KE

2 SEO | Dorset Coast.

DS EON Sa

1 KKK:

XK XKXKKKKXKXKXKKKKI:

XKKK: KKKKKKKKKK:

| Rhone Basin.

X re

wal)

Re

2 XX wX +e

KOKO Kap OA em | Wiirtemberg.

x

X eX

XXX XK XK

XxX XXX

ae 8

part 4] JURASSIC CHRONOLOGY: LIAS. 277

TasiE IX (continued).

Faunal Horizons. Areas.
ae Lg) re de:
a | Str Pesta toe
Se Ne bee ee He
She arise |e
oo |e) Wel Slo
Flelals |e
ren Clymense): 0.04... todd dae Gene. | x
He BUSLOCKICERAS: a2 5.< 828. eeasen ones: a ee
ae, | RC COROC TOS cia - sasiau4ce 22ers ee, Net ee a
enc g Se POVYOPIYLLUNE ... 0-. casncnennsveaacens x
ie ide | 4. oxynotum Be Pr a ier SSO, eR ec iel ME eae ae |
See p. 269 | eM CIEILNZD cc8 0s 2c thoes MORRO TE ge Dlpscrae) Wertoa! (oven 1 (he
P- ; PEO SU SOU 55. wivo. a inj Gi0eaei weeds tae a eg ia 9S
MPO OUICEV OS... vase acteomenaine teats: x x
( 7. denotatus Soin, reese erties | EAA ees | seh eR Re
MERCIAN. SET Se Re aT aoe i score oe) I OM
Age of | 5. planicosta ... / all aie x
Catagenetic < 4. sagittarium > acl acks x
Arietids. | ODEUSUME i isdee.a seas Ne IG LK
See p. 271. Z. brooks... AP: | x
L 1. turneri A eur acteurs Oe x
Cet esa eal Me cee LOS. [os ts
Be PIECCCPAS! ooo cfs Oe ied oc eek dn ngs PIES ORK PSE (PAI ts 28
nari at | 6. Agassiceras SOR DR. INSEE Pe aoe
Wie satis J 5. gmuendense cial ted cace nen ened Mae /sigh Nene (aeacen iba
Niet. | 4 CAR CUEGCLOTUL «Fea. cues we anaies o26 sva'ees| BAL al EEDA ISS iP OG
See p. 273 | 3. bucklandi es retieom |
ecg, 2. rotator Tp beta Ss ogee Aer ps toe Fea mene) E>, Sag ee Ga eG
Ne CVCCHIS bee es cecsinnee) Oe | OS ol Eh
|

[For the Hettangian sequence, see Appendix by Mr. Tutcher, p. 278.]

1 Suggested on the evidence of a fauna in the Yeovil & Bridport Sands.
2 See S.S. Buckman & E. Wilson, Q. J. G.S. vol. lii (1896) p. 688, footnote 2.

3 In Wiirtemberg Quenstedt’s Lias e« (=middle and lower parts of Whitbian)
seems to be fragmentary; but, on the other hand, it would appear to possess certain
horizons of its own not yet separated out in other areas.

4 Prechiella subcarinata is a notable and easily recognized species; but, perhaps,
somewhat too rare to be quite suitable for this scheme. It is in use for the horizon
where Hildoceras-bifrons forms are abundant. To prevent misconception it is
advisable to analyse further. F. subecarinata without H. bifrons forms is not yet
known to me; but the latter are found where the former is lacking. F. subcarinata
occurs in Yorkshire, the Midlands, in Somerset, but not in Dorset nor Gloucester-
shire. It occurs in the Rhone Basin, the Austrian Alps, and Italy, but not in
Wirtemberg. Its rarity may account for its absence, say, from Gloucestershire,
but can hardly be pleaded for the well-searched Dorset Coast, and certainly not for
so well-worked an area as Wiirtemberg. Absence of a special deposit seems to be
the explanation required there.

> The fauna of horizons 1-3 are illustrated in Reynés, ‘ Géol. Pal. Aveyron.’ 1868
Monestier’s paper, jam cit., refers to the same district.

278 MR. S. 8. BUCKMAN ON [ vol. lxxin,

best results the label should give not only the name of the place,
but the exact exposure—the more detailed the better. Then the
sequence of dissimilar faunas can be ascertained, especially when
the exposures stretch across the line of strike.

But, even with localities alone, much can be done by analysis.
and comparison.

Another lesson may be learnt—it has been taught that the
absence of the zone-species did not invalidate the placing of the
strata in such a zone, provided that the stratigraphical position was.
accordant: it was only a local pecuharity. Such an assumption
is now seen to be very unsafe: such cases must be looked upon with
considerable suspicion. Dissimilar faunas, of locomotive organisms.
like Ammonites, in contiguous areas are products, not of zoological,
but of stratigraphical differences. There are zoological provinces ;
but the absence of a southern fauna from a northern area may
mean less for difference of date than the absence of a northern
fauna from a southern area. Yet in the case of two areas in
approximately the same latitude, the absence from one of a fauna
well-developed at the other, both said to be on the same horizon,
may well cause doubt as to their contemporaneity. This is a true
case of dissimilar faunas.

The need for a much more systematic and continuous palzon-
tological output and for fuller illustration of species is obvious.
from this investigation, where much difficulty of interpretation is.
due to the uncertainty of unillustrated records. Such an investi-
gation as this is both hindered and hampered by the present con-
dition of paleontology, which cannot keep pace with,—in fact, is.
continually falling behind, the discovery of new material. Such
paleontological study requires very considerable time; and the
facilities for its prosecution and publication seem to be inadequate.

Finally, I take the whole responsibility for the interpretations
that I have placed on the information and evidence laid before me;
it must not be thought that my informants necessarily concur in my
views. For any mistakes—and it is too much to expect freedom
from error—I shall be to blame; but I will be grateful for any
facts which expose them.

AppenpDix I. THe Zonat SEQUENCE IN THE LOWER LIAS
(Lower Part). By J. W. TurcHer.

(1) Introduction.

The district of North Somerset and South Gloucestershire—
approximately that occupied by the Bristol Coalfields—has chiefly
come under my observation. In this district the Lias has been
thrown into a series of folds having, in the main, an east-to-west:
trend. These folds increase in intensity from north to south,
becoming more marked as the Mendip Hills are approached.
Partial and repeated denudation of the Jurassic rocks has followed

part 4] JURASSIC CHRONOLOGY : LIAS. 279

folding, thus causing numerous local:non-sequences. In the neigh-
bourhood of Radstock the sawzeanwm zone, in which occurs the
large number of Spirzferina walcotti for which that place is noted,
may be found resting indifferently on any earlier zone down to
langportensis (White Lias, see Table X below).

In the Keynsham area, which lies in the middle of the district
under consideration, the Lias occupies a shallow syncline, and the
beds have not been denuded to the same extent as those on the
south and north. Chiefly in this area the faunal sequence of
the Sinemurian deposits has been determined.

The Hettangian deposits, as a whole, are best displayed in an
area of which Bristol is the centre.

In the following table it will be observed that the White Lias
is included with the Hettangian. In common with the late
Dr. A. Vaughan and the late Edward Wilson, I have always held
the view that, for paleontological reasons, the line dividing Lias
from Rhetic (Hettangian from Rhetian) should be drawn at the
base of the White Lias. Mr. Buckman, it may be remarked, has
expressed the view that the Hettangian should be regarded as the
final phase of the Trias—on the grounds of the biological characters
of Ammonites, the decadent characters of Psiloceras and allies,
and the new departure (anagenetic characters) of the Arietide of
the Sinemurian.!

TABLE X.—ZONES OF THE LOWER LiAs (LOWER PART).

Ages. Zonal terms. Name of Index fossil.
. (| turneri. Arietites turneri (J. de C. Sowerby).
z sauzeanum. Agassiceras sauzeanum (D’Orbigny).
fe scipionianum. Atomoceras scipionianum (D’Orbigny).
5 + | gmuendense. Coroniceras gmuendense (Oppel).
e | bucklandi. Coroniceras bucklandi (J. Sowerby).
a rotiforme. Coroniceras rotiforme (J. Sowerby).
2 || conybeari. Vermiceras conybeari (J. Sowerby).
(| angulata. Schlotheimia angulata (Schlotheim).
, liasicus. Alsatites liasicus (D’Orbigny).
4 [megastoma. Wehneroceras megastoma (Wehner) }.
johnstoni. Caloceras johnstoni (J. de C. Sowerby).
rs planorbis. Psiloceras planorbis (J.de C. Sowerby).
s Ostrea. Ostrea liassica Strickland, and its
= mutations.
an tater. Pleuromya tatei Richardson & Tutcher.?
langportensis (White Lias).) Volsella langportensis, Richardson &
Tutcher.?

1 Not found in the district, but a Wehneroceras fauna occupies this posi-
tion elsewhere. See p. 280.

* Proc. Yorkshire Geol. Soc. vol. xix (1916) p. 52 & pl. viii, fig. 3.

3 Ibid. p. 54 & pl. ix, fig. 11.

1 «Jurassic Time’ Q. J. G.S. vol. liv (1898) pp. 444-47.

280. MR. S. S. BUCKMAN ON [vol. Ixxiu,

(2) Remarks on the Zones,

The turneri=semicostatum Zone ( pars) auctt.—More than one
species of Arzetites passes under this trivial name; it is, therefore,
desirable to indicate the form intended. This is an evolute shell,
with compressed sides, and rectangular whorl-section, agreeing
with the upper figure in pl. ecccli of the ‘Mineral Conchology,’
but not with Wright’s figs. 1-3 in pl. xu of his ‘Monograph of
the British Lias Ammonites.’

Numerous specimens of Arnioceras are associated with A. tur-
ner’ in this district, but since Arnioceras spp. also occur abun-
dantly in the sauzeanum-gmuendense zones, while A. turneri
is not found at these levels, the last-mentioned makes the better
zonal fossil.

The sawzeanum to conybeari Zones.—These zones are well
exhibited in the quarries about Keynsham. ‘The beds are of no
great thickness, but they are very fossiliferous, and the faunal
succession is quite clear. North and south of Keynsham some of
these zones are missing, notably conybeari and rotiforme, while
paucity of deposit and penecontemporancous erosion have resulted
in considerable compression of those remaining.

The angulata, liasicus, and megastoma Zones.—The beds con-
taining numerous species of Schlotheimia are well developed over
much of this district, although rarely complete at any one place.
Careful study of these beds has suggested division into two. well-
marked zones which have more than local application. The
angulata zone is thus restricted to the beds in the upper part of
the series. ‘These beds contain, in addition to the index-ammonite
and numerous allied species, an abundance of Rhynchonella calc-
costa Davidson (non Quenstedt). In the lower division (lzaszcus
zone) <dlsatites liastews (D’Orbigny), Schlotheimia gallica S.
Buckman, and Ornithella sarthacensis (D’Orbigny) are common
fossils, and they do not pass into the upper division.

No species of Wehneroceras have been obtained in this district,
and a non-sequence between johnstoni and liasicus deposits 1s
therefore assumed. Ammonites of this genus have, however, been
recorded from Hock Chiff, near Fretherne (Gloucestershire),! and
from Evesham ( Worcestershire ).?

An important Wehneroceras fauna occurs at Kayes Cement-
works, Long Itchington, near Southam (Warwickshire). The
extensive quarry at this place shows the following sequence :—

conybeart. Vermiceras spp., Coroniceras spp.

ae Schlotheimia angulata, Schl. striata (Quenstedt).
ee Rhynchonella calcicosta Davidson.
Ee j Alsatites liasicus (D’Orbigny), Schlotheimia spp.

Ornithella sarthacensis (D’Orbigny).
Wehneroceras extracostatum (Wehner),

megastoma. ee many other examples of the genus.

- a Richardson, Proc. Cotteswold Nat. F. C. vol. xvi (1908) p. 141.
2S. S. Buckman, ibid. vol. xv (1906) p. 246 & pl. x, figs. 5-6.

part 4] JURASSIC CHRONOLOGY : LIAS. 281

The specimens of Wehneroceras were obtained by Dr. Robson,
of Birmingham. He was informed by the quarrymen that these
specimens came from a temporary excavation at the base of the
section. On the occasion of my visit this excavation was water-
logged, and could not be examined. There is, however, every
reason to believe that the statement of the quarrymen is correct.
The state of preservation of the specimens is distinctive; they are
cleanly-cut casts in a bluish-grey matrix with some pyrites, and no
fossils have been found in a similar condition and matrix in any
part of the quarry usually worked.

The johnstont Zone-—The ammonite of most frequent occur-
rence in this zone in the Bristol district is Caloceras intermedium
(Portlock), but fragments attributed to C. johnstoni have been
obtained.

The planorbis Zone.—The true Psiloceras planorbis is rare in
the Bristol district; a more evolute form, Ps. sampsoni (Port-
lock), and a, costate form, Ps. plicatum (Quenstedt), are the
dominant species.

The Ostrea, tater, and langportensis Zones.——The term Ostrea
Zone has generally been used to distinguish all the Lias deposits
below those in which ammonites occur. It 1s now proposed to
restrict this term to the beds immediately preceding the planorbis
zone: in these beds Ostrea liassica and its mutations attain their
maximum.

Ostree of the liassica type also occur in decreasing numbers in
the lower beds ; but, in these deposits, other fossils acquire greater
importance.

The White Lias is characterized by Volsella (Modiola) lang-
portensis, which appears to be confined to these beds.

Between the White Lias and the maximum of Ostzea liassica
and its allies, there is a series of beds, more or less continuous
from Dorset to Yorkshire, containing in abundance Plewromya
tatet. ‘The application of this fossil to zonal purposes has, under
an older name (Pleuwromya crowcombeia), and in a somewhat
less restricted sense, already been suggested by Dr. A. Vaughan
in collaboration with the present writer,! and by Dr. Rendle Short.?

R. Tate & J. F. Blake designate the beds in which this fossil
occurs in Yorkshire ‘ The Plewromya Limestones.’ 3

! Proc. Bristol Nat. Soc. n.s. vol. x, 1903 (issued for 1901), pp. 52, 53
see also A. Vaughan, Q.J.G.S. vol. lix (1903) p. 400.

2 Q.J.G.58. vol. lx (1904) pp. 187, 188. . x

3 «The Yorkshire Lias’ 1876, p. 38.

282 MR. 8. 8S. BUCKMAN ON (vol. Ixxiu,

Apprenprix II.

MavyeEr-EYMAR’S STRATIGRAPHICAL TERMS.

Since this communication was read Dr. A. Morley Davies has
kindly brought to my notice a paper by Mayer-Eymar contain-
ing a scheme of stratigraphical terms. This paper seems to have
been overlooked generally, perhaps on account of its rarity. As
there is no copy in the Geological Society’s Library it seems
desirable to transcribe the necessary portion. I am much indebted
to the courtesy of Prof. Watts for the opportunity to do so. The
paper is entitled ‘ Die Filation der Belemnites acuti’ (Vierteljahr-
schrift der Ziircher Naturforschenden Gesellschaft, April 1884),
and the stratigraphical scheme is to explain the sequence of strata
containing these belemnites. The author speaks of a previous
scheme published three years earlier: substantially the same, one
may presume, but I have not been able to see it. Jam, however,
indebted to our Librarian, Mr. C. P. Chatwin, for bringing to my
notice in answer to my enquiries about this prior paper, another
communication by the author in the same year (1884)—a paper
of eight lithographed folios giving a classification of all strata.

The following Table XI (p. 283) is the table in the pamphlet
first cited, with certain correlations.

By the side of Mayer-Eymar’s table are placed the divisions
adopted in the present communication, and, alongside those,
Quenstedt’s divisions of the Lias; but it cannot be claimed that
the Swiss author’s divisions are rightly interpreted. For instance,
it is doubtful whether the Hwiccian is correctly correlated with his
Mendin: that may be intended for the lower part of the Domerian ;
and perhaps it is incorrect to leave the Raasayan without equi-
valent: some of the basal strata of the Rottortin and upper horizons
of the Balingin may fall within its limits. But Continental
authors have apparently only had the opportunity of seeing isolated
fragments of strata of Raasayan date, and may perhaps’ have
correlated these fragments criss-cross, placing earlier strata of one
locality above later strata of another. We had certainly done that
in this country before the Raasay deposits gave the clue.

Had I known about Mayer-Eymar’s scheme I should have
hesitated to propose some of the new terms; but my terms were
in print before his paper came to my notice! So I must leave
selection in the hands of my fellow-workers.

1 Abs. Proc. Geol. Soc. 1916-17, No. 1009, p. 84.

part 4] JURASSIC CHRONOLOGY: LIAS.

283

Taste XI.—Mayer-Eymar’s SCHEME, WITH CORRELATION.
Terms of Quenstedt’s

Mayer-Eymar’s Terms. present
paper.
Mittleres Jura-System.!

II. Bedfordin.— Niveau der
‘ BATHIAN Terebratula lagenalis.

- (Mayer-Eymar). I. Bradfordin.—Niveau des

Apiocrinus Parkinsoni.’
(III. Falaisin.—Niveau der Nevi-
nea Voltzi.
2 II. Stonesfieldiz.
Clypeus Ploti.
. Cadomin.—Haupt-Niveau der
Ke Ostrea acuminata.’
(III. Ehningin. — Haupt - Niveau

* VESULLIAN Niveau des

(Mayer-lKymar).

Hy

des Ammonites Parkinsoni.
Il. Scarboroughin.—Niveau des
Ammonites Humphriesi.
I. Maconin.—Haupt-Niveau des

|
‘ Basocian J
|
ly Ammonites Sowerbyi.’
r
|
|
<

(D’Orbigny).

Il]. Cheltenhamin.—Niveau des
Ammonites Murchisone.
Il. Gundershofin.—Niveau der
Trigonia navis.

I. Bollin.—Niveau des Ammon-
|
<

|

|

L

‘ AALENIAN
(Mayer-Eymar).

ites torulosus.
III. Alfeldin.—Haupt-Niveau des
Ammonites Jurensis.
IJ. Altorfin.—Niveau des Be-
lemnites acuarius. “aL:
I. Pliensbachin.—Niveau des Whitbian
Belemnites papillatus.’

Yeovilian.

‘TOARCIAN
(D’Orbigny).

Unteres Jura-System.

(me a,b. Banzin.— Niveau des
Pecten equivalvis.
‘ CHARMOUTHIAN | II a, 6. Mendin.— Haupt-Niveau Eviec
(Mayer-Eymar). 4 des Ammonites fimbriatus. ; i Sa
| I,a,6. Rottorfin.—Niveau des
Ke Ammonites Jamesoni.’

i Domerian.

} Wessexian.

Raasayan.

II, a,6,c. Balingin.—Niveaudes Deiran.

‘ SINEMURIAN Ammonites oxynotus. Mercian
(D’Orbigny). I,a,6. Filderin—Haupt-Niveau :
der Gryphea arcuata.’ Lymian.

II, a, 6. Hettangin.—Niveau des
‘RH#ZTIAN Ammonites angulatus. -
({Giimbel ] Ms-E.) I. Kessenin.—Niveau der Avi-

cula contorta.’

Hettangian.

LTias
Divisions.”

)
f Y
J
|

e)

1 The lithographed paper differs in not giving definite divisional terms such as

‘Banzin’ and so on, but speaks only of ‘ Couches de Banz’ and so on,

2 Quenstedt’s Lias Z includes beds higher and Jower than Yeovilian, and his Lias ¢

is of less extent than Whitbian.

284: MR. 8S. S. BUCKMAN ON [vol. lxxiui,

ApprEnpix III. PALZoONTOLOGY.
(a) Introduction.

In the following pages are given descriptions of certain Lias
species which are of importance, either because they are additions
to the British fauna, and therefore their recognition may be useful
in future work, or because they are of stratigraphical significance.
Some few of them happen also to be interesting morphologically
and biologically; but only casual notice of such features is
appropriate now.

A few words of explanation may be given here in reference to
the descriptions. The proportions are stated always in the order
proposed in ‘ Yorkshire 'Type Ammonites’ 1, p. vi (1913).—Dia-
meter in mm., breadth of whorl, thickness, size of umbilicus in
percentage of diameter; S., measurements from actual specimens,
F., from figures! T., from text-statements of author. Other
details about descriptive terms will be found in the same place.

At the close of the descriptions I append a few remarks as to the
bearing of the described species on the geological-chronological
problem (p. 807).

(6) Descriptions of Species.
Family HILDOCERATID.

Genus LEPTALEOCERAS,? nov.

Type, L. leptwm, sp. nov.

Definition.—An umbilicate, plate-like, obscurely costate,
gammiradiate, stoutly carinate, non-sulcate Hildoceratid. Carina
apparently degenerately septicariate, that is, the cast may not be
carinate or so carinate, thus indicating a one-time septate con-
dition; but there is apparently no distinct hollow in the keel:
details, however, are obscure. The radial line is of the gamma
pattern of Grammoceras, very slightly flexed laterally, produced
ventrally, but not excessively.

Distinction.—The stout carina recalls Tiltoniceras S. Buck-
man,? but shape, ornament, and radial line are wholly different.
There is some suggestion of Grammoceras Hyatt, but this plate-
like thin form could not give rise to the stout costates of that
lineage. There is a nearer approach to Protogrammoceras Spath,*

1 Measurements (especially of small forms) are difficult to obtain accurately.
In the case of figures it seems best to lay tracing-paper, and then by a ruler
mark diameter and proportions with a sharp pencil. This ensures a true
diameter being followed, and saves the plate from the compass-points: the
only error may be from the shadow of the umbilical wall.

* AerraXéos thin, fine, delicate.

$ * Yorkshire Type Ammonites’ ii (1913) p. viii.

+ Q.J.G.S. vol. lxix (1913) p. 547.

—_—

part 4] JURASSIC CHRONOLOGY: LIAS. 285

particularly in the plate-like shape; and the penultimate whorl-
section of Spath’s type agrees with the ultimate whorl-section of
this genus, suggestive perhaps of common ancestry; but the pre-
sent genus shows no peripheral sulcation, and has a decidedly
different radial line.

Remarks.—Spath says that his genus is ‘ probably .... far too
comprehensive.’! It is, therefore, inadvisable to enlarge it for the
reception of this form.

LEPTALEOCERAS LEPTUM, sp. nov. (Pl. XXVI, figs. 1 a-3 0.)

Description.—Serpenticone ; substeno-leptogyral; subextre-
milatumbilicate ; periphery subtabulate, joining a stout fastigate
earina with only a slightangle; gammiradiate; lateral area smooth
to costulate to smooth.

General details.—The flat, little-overlapping whorls give to
the species a disc-like appearance. The inner whorls are somewhat
elliptical in section, the outer whorl is suboblong, thickest about
the middle, sloping slightly to the periphery, more to the umbilical
edge, which is tabulate, narrow and defined in the last whorl, but
indistinct previously. The inner whorls are smooth until about
14 mm. diameter; then furnished with subobscure, undulate costule
which die away nearly to smoothness at about 53 mm. diameter
there remain only occasional traces of the previous costule with
fine growth-lines, and ultimately only the latter.

Remarks.—Three specimens are before me, all very similar ;
but the medium-sized one seems to differ in thickness and slightly
in other proportions from the holotype at the same diameter.

The likeness of the smooth anagenetic stage to the similar stage
in Arnioceras is noticeable (see p. 268).

Distinetion.—The considerable Italian literature on Domerian
Hildoceratide has revealed neither to Mr. Lang nor to myself
anything really like this species. I am much indebted to Mr. Lang
for kind assistance in bibliographic matters in connexion with this
Appendix—an important aid at the present time when facilities
are so much curtailed.

Below I give proportions of the examples of this species and of
others which have some approximation. Of these Ammonites
fieidingi seems to be the only one possibly of this genus; but its
radial line is perhaps too curved: it would represent the smooth
or almost smooth anagenetic stage in this or a parallel line; A.
pseudoradians has the right style of radial line, but a different
style of ribbing, and shows no sign of the smooth anagenetic stage ;
A. normanianus has the style of ribbing, but much too curved
a radial line; and the others differ by being carinatisuleates, with
also a too-much flexed radial line.

1 Q.J.G.S. vol: Ixix (1913) p. 580.

286 MR. S. S. BUCKMAN ON [vol. lxxin,

History of figured specimens.—The holotype is from the
collection of Mr. D. S. Darell, F.L.S., F.G.S., and was obtained
from South Petherton (Somerset), evidently by its matrix from
Marlstone or associated beds. The other two specimens were pur-
chased by Mr. J. G. Hamling, F.G.S., at the sale of the effects
of the late Rev. Ingle Dredge: they were in a drawer labelled
‘Middle Lias, Gretton.’ The piece of matrix which yielded the
larger specimen was preserved too—a very good practice: it is a
bluish calcareous stone of Marlstone character, and Gretton near
Winchcomb (Gloucestershire) was a well-known Marlstone locality.
See later, p. 308. I desire to express my thanks to Mr. Hamling
for kind presentation of these specimens.

TABLE XII.—PROPORTIONS: LEPTALEOCERAS AND LIKE FORMS.

L. leptum, young shell ».............. S. 25, 34, «19, 40,

24, 33, 18, 41,
Lleprumsemoloty pe. ¢0.4. 0.0028 8:4. 35355 our ake 43.
66, 24, 16, 52.
Dak, Tepiiie. Bete cacegcece eee ee S. 39°5, = ode 20, 39.
Ammonites normanianus D’Orbigny* T.90, ol, MGs 45.

Protogrammoceras cornacaldense,

var. zeugitanwm Spath, lii, la*.. T..60; 30, Iss 46.
Am. pseudoradians Reynés,i[{bis],4* F.46, ails Ze aie
Am. fieldingi Reynés, iy, la, b+ ... F, 24, 33, 24, 47,
Harpoceras domeriense Meneghini,

FATS. ALD? Gems Mer yaa eee Oren Proll oa 26, 48.

Family POLYMORPHID.

ACANTHOPLEUROCERAS RURSICOSTA, nom. nov. (Pl. XXVI,
figs. 4 a4 ¢.)

1884. Ammonites valdani Quenstedt (non D’Orbigny), ‘ Ammoniten d. Schwab-

ischen Jura’ pl. xxxv, fig. 4 only.

Proportions.—-s. { 260, 28, 20;. 48.

190, 32, 22, —.

Description.—The features of the type are its large size and
the yeclination of the ribbing. The general features are well shown
in Quenstedt’s cited figure—the reclination is less; but increase of -
reclination may be due to age, to which also is to be attributed loss
of inner row of tubercles, rounding of periphery, and decay of keel.
The proportions of Quenstedt’s fragment I estimate at F. 112, 30,
20, 48.

Distinction.—Reclination of ribs, presence of many marked
subsidiary costule on periphery, less size of tubercles, convexity
instead of concavity of intertuberculate lateral area distinguish

1 The specimen being broken, approximate measures of inner whorls can be
given.

2 «Pal. frang.: Terr. Jur. Céph.’ 1844, pl. Ixxxviii & p. 291.

3 Op. jam cit. + *Géol. Pal. Aveyron.’ 1868.

° * Lias sup.’ in Stoppani’s Pal. Lomb. (4) 1881.

part 4] JURASSIC CHRONOLOGY : LIAS. 287

this species from Ammonites valdant D’Orbigny.! Its whorls are
also somewhat broader and thicker. The proportions that he gives
are T. 95, 27, 17-19, 48.

History of figured specimen.—Given to me many years
ago by the late Rev. F. Smithe, F.G.5., with other large species,
as having been found in the Middle Lias clays of Leckhampton
(Gloucestershire), when the Banbury & Cheltenham Railway was
constructed.

Family ARIETIDA.

Genus RADSTOCKICERAS,” nov.
Type, &. complicatum, nov.

Definition.—Oxycone, highly involute, septicarinate ; peri-
phery concavifastigate. Radial line indistinct, laterally slightly
flexed ? slight curving forwards on outer third. Suture-line very
highly complicated—one line touching the preceding at so many
points as to make the separation of the chambers a very difficult
process. The peripheral lobe has two long branches, and five well-
developed branches penetrate the external saddle, four of them off
the side of the peripheral lobe; the superior lateral lobe narrow-
stemmed, strongly trilobate, unequal; inferior lateral lobe broad-
stemmed, with short lobules; a considerable array of auxiliary
lobes.

Distinetion.—The high degree of specialization of suture-line
distinguishes this genus from Oxynoticeras. Involution is rather
more developed; periphery is on rather a lower grade, but is
beginning to show the knife-edge of that genus, while suture-line
is well beyond it: the array of lobes external to the superior
lateral lobe is greater in number and more developed, that lobe is
specialized into a long narrow-stemmed lobe of cruciform pattern ;
while it is the inferior lateral lobe which is in the same stage as
the superior lateral of Oxynoticeras—broadly U-shaped with short
lobules.

RADSTOCKICERAS COMPLICATUM, sp.nov. (Pl. XXVII, figs. la&
16; text-figs. 6, p. 294 & 12, 21, p. 295.)

Description.—Oxycone ; subextremiplaty-leptogyral ; an-
gustumbilicate ; periphery concavitastigate, septicarinate; sub-
distanti-obscuricostate, gammiradiate ; complicati-septate.

General details.——The type is wholly septate: there are
indications of its having lost more than another half-whorl, so that
it was a giant of about 380 mm. or nearly 16 inches in diameter.
The periphery is not true knife-edge—the side falls into the keel
with a concave depression ; ‘ribs are rather distant and obscure ;
greatest breadth is about one-third from the umbilical border which

' «Pal. franc.: Terr. Jur. Céph.’ 1844, pl. lxxi & p. 255
2 Radstock (Somerset).

288 _ MRE. S. S. BUCKMAN ON (vol. xxii,

falls somewhat steeply to the umbilicus; excentrumbilication is
apparent in the last half-whorl (beyond the part preserved )—the
overlap decreasing from about four-fifths to two-thirds.

Remarks.—In ornament, periphery, and general appearance
the species here described conforms with Ammonites buvignert
Dumortier; but it differs in having a larger umbilicus with a much
steeper border and a thinner whorl the oreatest thickness of which
is not on the edge of the umbilical border but well removed from it.

Ammonites buvignert D’Orbigny is a much thinner species than
Dumortier’s, and has passed beyond the costate stage. Its um-
bilicus is much smaller than the Radstock species; its suture-line
shows the general pattern thereof, but is not truly conformable in
many respects: 1t does not seem so highly developed: the lobules
which penetrate the external saddle are much less developed and
different—the first lobule is long and bipartite in the Radstock
species, short and simple in D’Orbigny’s; the superior lateral lobe
has its outer lobule bipartite in the Radstock example, its inner
one is so in D’Orbigny’s: in the former the terminal lobule has its
shortest side internal (endobrachysceles), in the latter external
(ectobrachysceles).!_ The specimens figured by Dumortier and
D’Orbigny are both separable from the Radstock species by greater
ocelusion—they are perangustumbilicate. Pompeck] says that
these two ought to be considered as the same species :? I differ.

Phylloceras buvignert Wright is also a perangustumbilicate
oxycone, comparable as regards sculpture with D’Orbigny’s species,
but wholly different in whorl-shape and in suture-line. It looks
as if all these oxynotes are homceomorphous terminals of different
lineages—their polygenetic origin shown by the different character
which each selects for acceleration—in one case suture-line, in
another, ornament, in another, inclusion, in another, whorl-shape.
Considerable inequality of characters is thus produced.

For references and proportions see Table XIII, below.

History of figured specimen.— From Radstock Grove
(Kilmersdon Colliery), Radstock, Somerset, [from beds yielding
Oxynotoids immediately below the so-called ‘varzcostatus beds’ |.
Purchased. See p. 310.

TABLE XIIJ.—PROPORTIONS : RADSTOCKICERAS AND LIKE FORMS.

Radstockiceras complicatum nov. S. 186, 54, 25, i
S. 262, 55, 25, 11.
Ammonites buvigneri D’Orbigny®. F.200 (93), 56, 21, 4.
T. 200, 58, 21, 4,
Ammonites buvigneri Dumortier*. T. 126, 58, 28, 4.,
Phylloceras buvigneri (Wright),
Sa Waar eke Cee een as F.150, 54, 30, ie
T. 145, 56, 32, 4,
1 «Monogr. Inf. Oolite Ammonites’ p. 381.
2 «Oxynot. Siném.’ Comm. Serv. Geol. Port. vi (1906) p. 270.
% ¢ Pal. franc.: Terr. Jur. Céph.’ 1844, pl. lxxiv & p. 261.
4 «Bassin Rhone’ ii (1867) pl. xxxiv, p. 147.

‘Monogr. Lias Ammonites’ (Pal. Soc.).

part 4] JURASSIC CHRONOLOGY: LIAS, 289

Genus GLEVICERAS,! nov.
Type, G. glevense, nov. (paratype).

Definition.—Involute, septicarinate suboxycone, passing to
less involute, non-septicarinate platyecone—the periphery broaden-
ing, carina declining (passing to rounded, uncarinate ?), whorls
inflating. Ribs subregular, simple. Radial line laterally nearly
straight with distinct forward projection, less in stage of ‘rib-
decline. Suture-line somewhat complex—no long branches from
the external lobe, one accessory lobule in the external saddle,
superior lateral lobe rather long, narrow-stemmed, but declining to
broad-stemmed later.

Distinction.—From Oxynoticeras, the suture-line is more
developed, but the oxyconic character is much less developed,—
return towards platyeone commencing before anything like the
knife-edge periphery of Owynoticeras is attained. From Rad-
stockiceras, with a lower stage of involution and a rather less
developed periphery this genus combines a less complicated suture-
line. From Agassizocer« as, of which at one time I thought it
might be an involute development, a suture-line too much deve-
loped. See also another character below, p. 292.

Remarks.—The various species which appear to belong to this
genus are those cited in the Comparative Table. Ammonites
guibalianus D’Orbigny and A. victoris Dumortier must be ex-
cluded for various reasons. See below, p. 293.

GLEVICERAS GLEVENSE, nom. nov. (Pl. XXVII, figs. 2 & 3;
Pee fos. 1 & 2; Pl. XXIX, fig. 3: Pl. x fig. A:
text-figs. 4: & Db, p. 294; 11, 20, p. 295.)

1844. Ammonites greenhoughii a Buckman, ‘Geol. Chelt.’ new ed. p. 89.

1881. Amaltheus guibalianus Wright, ‘ Mon. Lias Amm.’ pl. xlv, figs. 6 & 7 only.

1904. Agassizoceras greenoughi S. Buckman (non Sowerby) in L. Richardson,

‘Handbook of the Geology of Cheltenham’ p. 212.

Cf. 1879. Ammonites guibali Reynés (non guibalianus D’Orbigny), ‘ Mon. Amm.’

pl. xlvi, fig. 13 only.

General details.—Whorls broad (inner margin rounded),
inclusion nearly to the inner edge of the preceding whorl up to
128 mm. diameter, im another ? whorl (not preserved) umbilical
expansion rapid, inclusion only about 3. Periphery sloping ogival,
with raised hollow keel up to about 86 mm. diameter, in another
half-whorl keel small, hollow character obsolescent, periphery
flattening but narrower than dorsum, in another halt-whorl peri-
phery flatly ogival, almost as broad as dorsum, carina almost
obsolete. Ribs indistinct, undulate, occasionally bifureate on the
outer margin: they tend to become irregularly obsolete at or after
145 mm. diameter, when regular swellings (old-age rugosities )
appear.

| Final stage (not preserved), smooth (or irregularly swollen)
with rounded uncarinate periphery and excentrumbilication ? |

' Glevum, the Roman name for Gloucester.

Q.J.G.S8. No. 292. Dass

290 MR. 8. S. BUCKMAN ON [vol. lxxiii,

Remarks.—These details are drawn up from the holotype. The
paratype, Ammonites greenhoughii of the ‘ Geol. Chelt.,’ agrees so
closely with Wright’s cited figures of Amaltheus guibalianus and
his description of that form (p. 386), that there need be added
only these remarks :—The periphery in Wright’s figure is sharper,
possibly due to presence of test, the ribs are stronger—over-
accentuation of such a character is quite usual in drawings,—and
the inner edge of the penultimate whorl is more exposed: the
paratype, and the holotype too, show a particularly concentric
coiling of the umbilicus, which may be called thimble-shaped,
indicating that in the young the species must be rather thin and
somewhat widely umbilicate.

The paratype shows (Pl. XXVIII, fig. 2) a rather narrow-
stemmed superior lateral lobe, with a fairly even arrangement of
fine lobules towards the end: the broader-stemmed lobe of the
holotype is presumed to be due to old age.

Below are given the proportions of certain comparable species
with those of the species now described. The first three differ in
proportions, especially in the greater umbilication; Reyneés’s
Ammonites guibali is difficult to place in the series, as no informa-
tion is given of thickness nor whether it is a large shell reduced.

The very longstanding and very general confusion of Oxynotoids
of the Gleviceras pattern with Ammonites greenought J. Sowerby
- has now been exposed and corrected in a very careful paper by
Mr. Spath.! But the likeness when, in large specimens of the
present species, ribs are lost and the keel 1s obsolescent or obsolete
is certainly remarkable.

History of specimens.—The holotype is from Laas clays
above the oxynotum horizon, from the lower part of Folly Lane
Brickyard, Cheltenham (Gloucestershire). The paratype was re-
corded as Ammonites greenhoughit from Lias shales, Lansdown,
Cheltenham, Coll. J. Buckman (‘ Geol. Chelt.” p. 89).

TABLE XIV.—PROPORTIONS: GLEVICERAS AND LIKE FORMS.

Am. doris Reynts, xi, 13-152 .. F109, 48, Soe
Am. aballoensis Dum. II, xxxviii.® alate 48, aD, 20.
Am. greenoughi Hauer, xii, 2, 3, 4.4 i chee ba 48, 29, 20.

Am. guibali Reynés, xlvi, 13? ... F. 2038, 47, —, 20.
f 86, 47, 25, ile
Gleviceras glevense, holotype ...... 2) 128, Die 26, 14,
184, ail 27, 14,
G. glevense, paratype ............... S. 148, 52, 26, 14°5.
(Am. greenhoughw J. Buckman.)
G. glevense.
(Amaltheus gwibalianus Wright, ( F.157, 54, 26, 14.
KlVs LOMAS OOO) iy ake conta eee (Us 13333, 56, 26, 15.

1 * Schlotheimia Gireenoughi’ Geol. Mag. dec. 6, vol. ii (1915) p. 97.
2 *Mon. Amm.’ 1879. 3 * Bassin Rhone.’

4 *Ceph. N.O.-Alpen’ Denkschr. k. Akad. Wissensch. Wien, vol. xi, 1856.
.» ‘Monogr. Lias Ammonites’ (Pal. Soc.) 1881.

part 4] JURASSIC CHRONOLOGY: LIAS. 291

[Since this paper was read various other items of Gleviceras
belonging or akin to the present species have come to light, and
are of particular interest.

A large septate specimen from the same place as the holotype,
and like it only a half, has, however, stouter proportions: it is,
perhaps, more phylogerontic. It shows about a quarter-whorl
more; but, what is chiefly interesting is, that the mark of the
inner margin indicates that another complete whorl at least must
have been present.! As the specimen now measures 204 mm. it
must, judging by the proportion of radius to diameter as well as by
curvature, have been a giant of some 450 mm. diameter. But this
inner margin line shows excentrumbilication ; for, whereas about
80 per cent. of the whorl was enveloped at one time, in a whorl this
has decreased to about 66 per cent., and in less than another half-
whorl to about 50 per cent. From this specimen the following
proportions may be ascertained :—

140, 52, 3h, (162).
8.4 204, 51, a3 19.
450, 4S, ae 25.

The umbilicus in old age returns to the somewhat open condition
of youth, which is possessed by the young form described in the
following paragraph.

The next specimen, quite a young example, is also from the same
place; envelopment is about half the whorl; ribs are regular, with
occasional bifureation; there are no signs of auriculoids on the
exposed part of the whorl, but there is evidence that they existed
in the young stage: the line of the inner margin does not follow
a regular curve, but is angular (hexagonal in a turn), displaced at
intervals, thrown out of its course, by the presence of the auriculoid
excrescences—something similar may be noted in the umbilical
margin of spinous species.

This example, which is depicted in Pl. XX VII, fig. 3; Pl. X XIX,
fig. 3; and Pl. XXX, fig. 4, gives the following proportions :—

A ies 49, 29, oA Ke 2
eo 48, 27, 22, +K. *

The next specimen is from Charmouth, a ‘pyritised Oxyno-

1 Tn the course of these investigations I have made a discovery which may
be of importance for the identification of types. In my father’s descriptions
of ammonites, ‘Geology of Cheltenham’ new ed. 1844 (1845), the diameter
given is not that of the specimen as preserved, but is the assumed diameter of
the perfect shell. Thus, in his description of Ammonites gracilis (p. 104), the
diameter is given as ‘about 9 in.’ The specimen actually measures 145 mm.
(5% inches) in diameter, but is fully septate and carries indications of another
half-whorl at least, shown by remains of inner edge. The diameter of 9 inches
is Obviously reckoned to include this extra half-whorl or so, but is, perhaps,
rather an overestimate. This method of giving diameters, now that it is
discovered, clears up many discrepancies in these descriptions. It may be
that other authors have adopted this plan, which might easily raise doubts as
to the identity of types. There is no possible question about the identity of
A. gracilis.

2 Without keel, with keel.

2a 2

292 MR. S. S. BUCKMAN ON (vol. lxxiii,

ticeras, presumably from Bed 92,1 and is in the cabinet of
Mr. James Francis, F.G.S., who has kindly consented to its use in
illustration. It was communicated to me by Dr. A. Morley Davies,
who had noticed its interest in regard to auriculoids.

This is not the same species as the last, but it is near, and it
illustrates that which there is reason to suppose is the hidden stage
of that one. It is earlier—that is pre- -glevense—biologically, and
may, for the present, be inscribed as Gleviceras auritulwm/glevense.
It is earlier because, though exposing three-quarters of the whorl
shown by the young G. glevense, it retains auriculoids all the time,
which feature the other had lost about a whorl before. Its ribs
are also of a different pattern, somewhat irregular, connate on the
inner area, joined in button-and-loop style on the outer area by the

reflected U-shaped auriculoid: a plain rib parts each connected
pair. The umbilicus is angulate. Proportions are not much
different; but the periphery is rather blunter. The specimen
depicted in Pl. XXX, figs. 5a-5} & Pl. XXXI, figs. la—1L}, gives:

S. 22, 4A, 29, 26, =e

The last of these specimens is much separated by its shape, but
becomes of interest now as possessing auriculoids combined with a
stout whorl and flattened broad periphery.” It 1s Ammonites
ripartus Oppel,? from a well at Aston Cross, near Tewkesbury,
presumably from the dferwm horizon. It is thus additionally
interesting, as another link between the Gloucestershire and
Wiir temberg faunas.*

Neither Oppel’ s figure nor description lead one to expect auri-
culoids; but this example shows them well developed: they are
connected too by a longitudinal ridge or pseudo-carina—this is
shown by Oppel. The inner margin in the umbilicus is angulate,
as noticed for the two preceding specimens : not shown by Oppel.

This species may presumably be inscribed as Gleviceras ripa-
rium (Oppel), for it shows a suture-line (Oppel)—not well
exposed in my example (but see Pl. XXX, fig. 3d),—which appears
to be somewhat more developed than one would expect for this stage
of Oxynoticeras; but there are obviously several steps yet to be
distinctively named connecting this species with the last specimen
(G. auritulum / glevense) : they are supplied to a certain extent
by Quenstedt’s figures, pl. xxiv, figs. 15 & 16 in ‘Ammoniten d.
Schwabischen Jura.’ At any rate something very near to this
species’ may be looked for as common ancestor of Oxynoticeras
and Gleviceras, which are thus presumably traceable to a form of
Agassiceras pattern but possessing auriculoids, and thus differing
from that genus.

For further remarks on auriculoids, Ammonites auritulus, ete.,

see ‘Yorkshire Type Ammonites’ A. denny? 1909, No. 7. |

See Chronological paper. Table V facing p. 267.

Its approximate proportions are: 8.32, 48, 50, 29+.
Pal. Mitth. 1862, pl. x], fig. 2.

See Chronological paper, p. 270. -

me & Le

part 4] JURASSIC CHRONOLOGY: LIAS. : 293

Genus GUIBALICERAS, nov. (Figs. 14 & 18, p. 295.)
Type, Am. guibalianus D’Orbigny.!

Distinct from Gleviceras by the intermittent character of its
ribbing and also by its suture-line. Am. aballoensis Dumortier
pars,*and Amaltheus guibalianus Wright pars? (non D’Orbigny),
have the intermittent style of ribbing, and presumably belong to
this genus.

Genus VICTORICERAS, nov. (Figs. 13 & 19, p. 295.)
Type, Ammonites victoris Dumortier.*

Distinct from Gileviceras by different suture-line, pecuhar
character of test—striate and punctate,°—dichotomous style of
ribbing and other characters. The dichotomy begins at the un-
bilicus, where there is a sort of bunching on the umbilical wall, and
is repeated at several stages across the whorl, with short costule,
dichotomous or intercalated, on the periphery.

Fine examples of Ammonites victoris occur with Radstockiceras
at Radstock, with many other remarkable Oxynotoids which must
be left for another opportunity.

The suture-lines of some of these Oxynotoid genera are presented
in figs. 1-6, p. 294 :—

Fig. 1. Oxynoticeras oxynotum (Quenstedt), after his figure, Ceph. v, 11.

Figs. 2a & 2b. O. oxynotum (Quenstedt), from a paratype of Am. cultellus
J. Buckman in my collection, to show increase of complexity due to
age. The specimen, wholly septate, measures 1238 mm. (nearly
5 inches) in diameter; and suture-line 2a is taken at a diameter of
about 31 mm., 2b at about 90 mm.

Fig. 3. Oxynoticeras polyophyllum (Simpson), after the figure in ‘ Yorkshire
Type Ammonites’ 1909, No. 8.

Fig. 4. Gleviceras glevense, genotype, from the specimen figured in Pl. XXVIII,
fig. 2.

Fig. 5. Gleviceras glevense, holotype, from the large specimen illustrated in

Pi XX VIL, fig. 1.

Fig. 6. Radstockiceras complicatum, from the specimen depicted in Pl. XX VII,

fig. 1, the suture-line X 0°67: from a photograph.

To facilitate comparison of the various Oxynotoid genera, out-
lines of the external lobe and saddle and the superior lateral lobe
are given in figs. 8-14, p. 295 :—

Fig. 8. Oxynoticeras oxynotum, after Quenstedt, «K 2°5.

Fig. 9. O. oxynotum (Ammonites cultellus), see above, fig. 2 b.

Fig. 10. O. polyophyllum, see above, fig. 3.

Fig. 11. Gleviceras glevense, see above, fig. 4.

* Fig. 12. Radstockiceras complicatum, see above, fig. 5.

Fig. 13. Victoriceras victoris (Dumortier), after his fig. op. cit. pl. xxxi, fig. 1.
Fig. 14. Gwibaliceras guibalianwm (D’Orbigny), after his fig. loc. cit.

! ‘Pal. franc. : Terr. Jur’ Céph.’ pl. lxxiii.

2 «Bassin Rhone’ ii, pl. xxvii only.

% * Monogr. Lias Ammonites’ 1881, pl. xlv, figs. 3,.4 only.
+ Op. cit. ii, pl. xlv, figs. 1 & 2.

®> See Dumortier, pl. xxxi, figs. 1 & 2.

Figs. 1-7.—Suture-lines of Oxynotoids and a Deroceras.

ie sac

zaOx.oxynotum

(Am. cultellus)

<<

1-Ox, oxynotum

d Hi ie

26 Ox.oxynotum (Am.cultellus)

Bee

3. Ox.polyophyllum

7. Deroceras bispinigerum x 3.5

Nat RA

6. Radstockiceras complicatum X 0.67.

§. Gleviceras glevense (Holotype)

[For fig. 7, see p. 302. }

Figs. 8-21.— Suture-lines (skeleton) and radial lines of Oxynotords.

8 Ox. oxynotumx:z.5
| ( , 2 : rs Ox.oxynotum

9 Ox.oxynotum Am.(cultellus)

18 Guibaliceras
guibalianum

17 Ox.polyophyllum

zo Ox.polyophyllum €

11 Gleviceras glevense

iz Radstockiccras complicatum

oy

13.Victoriceras victoris

a

14 Guibaliceras guibalianum

t9 Victoriceras 16 Ox.oynotum
victoris ; Am. (cultellus)

21 Radstockiceras
complicatum

zo Gleviceras glevense

[In figs. 9 & 16, for Am. (cultellus) read (Am. cultellus). |

296 MR. 8. S. BUCKMAN ON [vol. lxxin,

For the same purpose of comparison, outline rib-schemes are
given in figs. 15-21, p. 295 :—
Fig.15. Oxynoticeras oxynotum, after Quenstedt.
Fig.16. O. oxynotwm (Ammonites cultellus), see note to fig. 2 above.
Fig. 17. O. polyophyllum, after fig. in Y. T. A., see note to fig. 3 above.
Fig. 18. Guwibaliceras guibalianwm, after D’Orbigny.
Fig. 19. Victoriceras victoris, after Dumortier.
Fig. 20. Gleviceras glevense, from the specimen figured in Pl. XXVIII, fig. 2.
Fig. 21. Radstockiceras complicatum, from the specimen depicted in Pl. XX VII,
fig. 1: this outline is of the natural size.

The genotypes of these Oxynotoid genera are all in about the
same stage of morphic equivalence, but all differ in degree of
development of various characters. Thus, in regard to suture-line,
some make more elaboration in the lobules of the external saddle,
some in the superior lateral lobe; in regard to periphery, Oxyno-
ticeras is the only one that has attained to the knife- edge stage,
Radstockiceras approaches, Gleviceras is far from 1t. An analysis
of the genera on these and other features gives the following
results in descending order :—

Saddle. Sup. lat. lobe. Periphery.
5. Radstockiceras. 5. Radstockiceras. 5. Oxynoticeras.
4. Oxynoticeras. 4. Gleviceras. 4, Radstockiceras.
3. Guibaliceras. 3. Victoriceras. 3. Guibaliceras.
2. Victoriceras. 2. Gwibaliceras. 2. Victoriceras.
1. Gleviceras. 1. Oxynoticeras. 1. Gleviceras.
Ribbing. Umbilicus. Result: Nat. Order.
5. Victoriceras. 5. Radstockiceras. 5. Radstockiceras (22).
4. Oxynoticeras. 4. Victoriceras. 4. Oxynoticeras (17).
3. Radstockiceras. 3. Oxynoticeras. 3. Victoriceras (16).
2. Gleviceras. 2. Guibaliceras. 2. Guibaliceras (11).
1. Gwibaliceras. 1. Gleviceras. 1. Gleviceras (9).

The natural order is arrived at by adding the position-marks
attained under the five different bases of analysis.

Amaltheus lymensis Wright (pl. xlvi, figs. 1-3 & pkexivn,
figs. 1-3) cited as Oxy ynoticerc as lymense in my Chronological paper,
p- 270, would seem not to belong to any of these genera. To be
Oxynoticeras it should have a suture-line more complicated than
that of O. polyophyllum, but its skeleton outline is more that of
Guibaliceras.

Genus ARIETITES Waagen.

ARIETITES TURGESCENS, sp. nov. (Pl. XXIX, figs. 2a & 206;
PIO, te. 152)

Cf. 1864. Ammonites turneri Wright (non J. de C. Sowerby sp.), ‘Amm. of Lias”
Proc. Cotteswold Club, 11, pl. i, fig. 4.

Cf. 1879. Arietites turneri Wright (non J. de C. Sowerby sp.), ‘Lias Ammonites ’
pl. xii, figs. 1-3; 1881, p. 292.

Cf. 1879. Ammonites brooki Reynés (non J. Sowerby sp.), ‘Mon. Amm.’ pl. xin,
figs. 6 & 7.!

1 These three references happen to be all figures of one specimen ; see p. 322.

part 4) JURASSIC CHRONOLOGY : LIAS. 297

Description.—Serpenticone; platysubpachygyral, latumbili-
eate to perlatumbilicate, carinati-sulcate, costate, gammiradiate.

Remarks.—This inflated Avrzetites is suthciently well repre-
sented in Wright’s figure and description, although Wright’s form
attained to somewhat greater stoutness at an earlier age. Reynés’s
shell has similar proportions to Wright’s 1879 figure, but is some-
what different in ribbing! The shell now described is neither
A. turneri nor A. brooki, as the proportions stated on p. 298 will
show; it is an inflated development of dA. furneri, and is not
intermediate between A. turneri and A. brooki, as the latter
belongs to the compressed stock.

Apart from its geological interest, which will be discussed pre-
sently (p. 311), and its biological interest as an inflated Arzetites,
the shell now described is noticeable for a pathological development.
On the periphery of the last quarter of the outer whorl the strong
keel and furrows suddenly cease, and a rounded venter is pr siiear
the much ventrally- -projected radii which accompanied keel and
furrows—one of the generic characters of Arietites—also suddenly
give place to radii crossing the venter with a slight linguiform bend
(Pl. XXXI, fig.5). This change is presumably due to injury, and
the injury has brought on highly-accelerated catagenesis of the
periphery, but has not affected the strength of the lateral ribs
We know that catagenesis is the reversal of anagenesis, and we
know from allied stocks that keel and furrows ultimately die away
leaving a rounded venter; also that highly-projected ventral radii
will return to a less projected state. But such catagenesis is
‘usually gradual, and comes on with general decay of ornament all
over, usually after a period of compression with umbilical contrac-
tion. Here the catagenesis is local, and is. produced in a sudden
jump *: the specimen was in a flourishing state, and apparently was
on its way (see Wright's example) to produce thicker forms.

I have had by me for many years a considerable series of these
pathological specimens, having had hopes of illustrating and dis-
cussing them. They should be of more than ordinary interest,
because in connexion with the law of tachygenesis, and with the
law of catagenesis being the reversal of anagenesis, they might
contribute important items of knowledge to the science of
pathology.

History of the figured specimen.—From a hard bluish,
decomposing to a soft white (chalky) matrix of Lower Lias, out
of the excavation for the reservoir of the Bristol Waterworks at
Barrow Gurney (North Somerset)—purchased. In the aperture is
a small Xipheroceras of the planicosta style.

1 But see p. 322.

2 It is noteworthy that, as yet, there are no known descendants of Arietites °
reproducing the rounded venter of this sudden jump. The nearest analogues
are the degenerate Asterocerates of the sagittariwm pattern (see Chronological
paper, p. 271),and so far as is known they are evolved by gradual change and
normal earlier inheritance of characters (tachygenesis) as is the case with
other ammonites.

298 MR. S. 8S. BUCKMAN ON [ vol. Ixxiii,

TABLE XV.—PROPORTIONS: ARIETITES
(BROOKI AND TURGESCENS SERIES).

( Arietites aff. plotti (Reynés).
| (Ar. bonnardii Wright, xi, p. 287).' F. 114, 22, 20, SV
Par raps —.
Arietites plotti (Reyneés).
(Am. plotti Reynés, xxxvi, 15, 16).* Bagge 26, 235 Deke
Arietites turnert (J. de C. Sowerby).
(Ammonites turneri Sowerby,

aS 2 | cevelit, top fe.) ee cee tee d Daa he J 32, [26], 46.
SE 4 (Am. turnert Reynés, xl, 18,19)? F. 65, 31, 26, 46.
Sw | Arietites sp.
(Arietites sp. Lang, from Bed 77),.4 S. 538, 34, 26?, 40?
Arietites brooki (J. Sowerby).

(Ammonites brooki Wright, ii, 5) °. ie toes 37, 27, 34.
(Am. brooki Wright, vi, 4, p. 280)' F. 142, 37, —, 34,
T. 140, 39, 28, —.
| (Am. brooki Reynés, xxxvii, 5, 6).? F. 147, 36, 27, SD.
| (Am. brooki Sowerby, exc)? ......... F. 148, 40P —, 3D.
< a | teat turgescens, NOV.© ..........«. Se LT 33, 32, 45.

&-= 4 Arietites aff. turgescens.
Ss (Ar. turneri Wright, xii, 1-3)} ... F. 53, 35.0 paaeneeeee:
8 F. 118, 375 ) Sas
T.115, 35.0.2

Genus ARNIOCERAS Hyatt.
ARNIOCERAS FLAVUM, nom. nov. (Pl. XXXLJ, figs. 2¢@ & 256.)

1878. Arietites semicostatus Wright (non Young & Bird sp.), ‘ Lias Ammonites
pl. 1, fig. 7 only. é
Description.—Subplaty-subleptogyral; subextremilatumbili-
cate; periphery fastigate, distincti-carinate; whorls smooth ; suture-
line simple, external lobe about as long as superior lateral.
Remarks.—A smooth, keeled <Arnioceras, possibly adult.
Arniocerates in the smooth stage have been made types of five
species, and names of other species have beenapplied tothem. For
consideration now are—
. 1858, Ammonites miserubilis Quenstedt.
. 1867, Psiloceras acutidorsale Hyatt.
. 1867, Arnioceras cunertforme Hyatt.
. 1876, Zgoceras nigrum Blake.

. 1878, Arietites semicostatus Wright (non Young & Bird sp.).
. 1883, Ammonites falcaries levissimus Quenstedt.

Dob WMH

The species now described, however, agrees only with Wright’s,
judging his figure as depicting a keel, for Hyatt’s and Blake’s species
are both ruled out by their peripheries. Ps¢loceras acutidorsale
has ‘abdomen prominent, acute,—no mention of a distinct keel;
Blake’s Aigoceras nigrum has an ‘angular front’; and Hyatt’s
Arnioceras cunetforme is figured with merely a sharply angulate
periphery ; Ammonites falcaries levissimus is different in pro-
portions, so there remains only A. miserabilis, which Quenstedt

1 ¢Monogr. Lias Ammonites.’ 2 «Mon. Amm.’ 1879.
3 “Mineral Conchology.’ + See Chronological paper, p. 271.
° Proc. Cotteswold F. C. vol. iii, 1864. © Where the keel ends.

part 4] JURASSIC CHRONOLOGY: LIAS. : 299

described as having a keel like a piece of string rolled round.! This
fits the present species well; there is a distinct angle at the jJunc-
tion of periphery and keel; but Quenstedt’s is a more slowly coiled
form. The present species has the side-view of Blake’s digoceras
nigrum, but the periphery of Quenstedt’s Ammonites miserabilis.

Before proceeding further it is necessary to mention Hyatt’s
and Quenstedt’s later interpretations of their species. In 1889
Hyatt recognized his Pstloceras acutidorsale as an Arnioceras,
and identified it as one variety of Ammonites miserabilis, his
Arnioceras cunetforme being another. He then gave figures of
these forms, and these figures must be regarded as at least the
lectotypes of his original species. But his original description of
A. cuwneiforme speaks of ‘ pile’ on the side, and ‘a keel indicated
by a ridge; channels obsolete —characters which do not seem to
appear in his later figures. In this case, if not in the former, he
possibly combined various forms in his two species.

Quenstedt has also combined various forms in his later work—

*Ammoniten d. Schwabischen Jura’ pl. xi, figs. 27-30. His

figs. 27 & 28 are without distinct keel, his fig. 29 has a distinct
keel; and his fig. 30 from Tewkesbury has, in my opinion, nothing
to do with riccerds: it is a young stage of Bifericeras.’

A table of the proportions of the various forms discussed may
now be given.

TABLE XVI.—PROPORTIONS: ARNIOCERAS, SMOOTH SPECIES.

Periphery angulate.

1. Arnioceras cf. acutidorsale (Hyatt).
(Ammonites miserabilis Quenstedt, xiii,

es oe spe hae ce lees F. 26, 22, 20, 60.

(Am. miserabilis Quenstedt xiii, 28)? ... BY Vb 22% 21, 59.

2. Arnioceras acutidorsale (Hyatt), ii, 4+ ... F. 32, 26, =, 54.

3. Arnioceras cuneiforme Hyatt, 1.54 ...... B20 ay 2b: 2A Py aoe
4. Arnioceras nigrum (Blake).

(Agoceras nigrum Blake, vi, 6)° ......... (F.20°5, 28, —, 49,

UT T9: i. 26, —
Periphery with distinct keel.

1. Arnioceras aff. miserabile (Quenstedt).
(Ammonites miserabilis Quenstedt, pl.
SLE, 1512 1S) SG a ae ei Bey, 22, 19, 59.
2. Arnioceras miserabile (Quenstedt).
(Ammonites miserabilis, Quenstedt, pl.

TLL UG 27) Rael a By 16%» 1 2a5 —, 56.

3. Arnioceras flavum, nov.
(Arietites semicostatus Wright, i, 7)? ... F. 28, 26, —, 52.
iholotype, Pl. XX XT, fig, 2) ......c.665.68. S. 25, 27, 20, 51.

4, Arnioceras levissimum (Quenstedt).
(Ammonites falcaries levissimus Quen-

Perec, ATs fee TS) F a hes dole eae cies F. 30, 33, 21, 44,
1“¢Ammoniten d. Schwabischen Jura’ p. 71.
2 ‘Yorkshire Type Ammonites’ ii (1918) p. iii. 3 Op. jam cit.
4 *Gen. Arietide.’ 5 R. Tate & J. F. Blake, ‘ Yorkshire Lias ’ 1876.

6 Op. jam cit. 1856. 7 Monogr. Lias Ammonites ’ 1878.

300 MR. 8. 8S. BUCKMAN ON (vol. Ixxi,

If these forms were to be combined under one name as Arnioeeras
miserabile without taking account of the differences of periphery
and proportions, it is possible that certain facts of geographical
and stratigraphical distribution might be overlooked for want of
distinctive appellations. It is not yet known that the different
forms are of strictly identical dates; and on the geographical
distribution something will be said later (p. 314).

Facts of evolution might also be lost without distinctive names.
For there seem to be really two lines developing side by side—one
in which the periphery proceeds no further than the angulate stage
but the whorl increases laterally—in thickness; the other in which
the periphery proceeds past the angulate stage to a carima with
indications of channels, but the lateral development lags behind—
the increase in whorl-thickness is slower. Of the first series 1-3
are morphic equivalents of 1, 2 of the second; 4 of the first is in
the same relation to 3 of the second, while 4 of the second stands
isolated.

To Hyatt’s idea that the smooth forms of Arnioceras are
derivates of Pszloceras planorbis I cannot assent. Ps. planorbis
and like smooth forms of that genus are catagenetic—post-costate
—developments with a degenerating phylloid suture-line. The
smooth forms of Arnioceras are anagenetic developments—pre-
costate—with a ceratitic suture-line, simple because undeveloped.
The likeness is deceptive: it isa case of transversal homceomorphy.!

The: next species well illustrates the precostate character of
smooth Arnioceras.

History of figured specimen.—From the Lias of Lyme ©
Regis (Dorset)—purchased there. It is yellowish-brown—hence
the trivial name—the colour which Sowerby illustrates for his
Ammonites brooki.2. This character may perhaps be a means of
fixing its exact stratigraphical position. See later, p. 314.

ARNIOCERAS ANAGENETICUM, sp. nov. (Pl. XXXI, figs. 3a—3d.)

Cf. 1889. Arnioceras semicostatum Hyatt (non Young & Bird sp.), ‘Gen. Ariet.”
pl. u, fig. 10 only.—Proportions: F. 34, 26, 26, 5].

Proportions. {S8.24, 338, 25, 44.

Sea,” 275. 2024)" Od.

Description.—Serpenticone ; subplaty-subleptogyral ; subex-
tremilatumbilicate ; carinati-subsuleate; mainly smooth, finishing
costate, parvinodate.

General details.—The distinctive feature of this species is a
prolonged smooth or nearly smooth stage, for over most of this
stage capillation and occasional very obscure costule may be
detected. On the last quarter-whorl are developed what must
be regarded as adult or even old-age characters—costz plain at
first, but later on bearing incipient tuberculation—small nodes.

1 «Yorkshire Type Ammonites’ ii (1918) p. vi.
2 * Mineral Conchology’ 1818, pl. exc.

»

part 4] JURASSIC CHRONOLOGY : LIAS. 301

‘The periphery at the beginning of the last whorl is carinate and
tabulate; at the end of it, carinate-subsulcate. Body-chamber just
under half a whorl, specimen being presumably complete.

Remarks.—The smooth stage of this species being distinctly
keeled connects it with the keeled series of smooth Arniocerates,
and it is presumably a development of the mserabile-flavum line.
The ribs being only slightly reclinate it may reasonably pass into the
Arnioceras-bodleyz series of costate Arniocerates ; less likely into
the next species. In the species now described the ribs are an adult
or old-age feature, in the costate Arniocerates a juvenile character
—an illustration of the law of tachygenesis. In the species now
described small nodes make their appearance almost as soon as
ribs; but in some lines of costate Arniocerates nodes are long in
appearing—may not appear at all. The difference in the time of
developing nodes may be a means of distinguishing lineages in
costate Arniocerates, as the time of carination seems to be among
the smooth forms.

History of figured specimen.—From blue Lias Limestone
of Lyme Regis (Dorset)—-purchased there. The test has the same
colour as Arnioceras flavum. In the matrix is a small example of

what is perhaps C ymbites.

[Since this paper was read I have obtained the presumed holotype
of Ammonites semicostatus Young & Bird. It is illustrated in
‘Yorkshire Type Ammonites ’ 1918, pl. exu.]|

ABNIOCERAS FORTUNATUM, sp.nov. (Pl. XXVIII, fig. 4; PI.
XXXI, figs. 4a & 40.)
Cf. 1883. Ammonites ceratitoides Quenstedt, “Ammoniten d. Schwabischen Jura’
pl. xin, fig. 8 (not of ‘ Cephalopoden’ 1849, pl. xix, fig. 13).

Description.—Serpenticone ; subplatygyral to substenogyral ;
leptogyral ; subextremilatumbilicate ; carinate-sulcate ; rursisub-
recticostate, parvinodate. Smooth stage to about 10 mm. diameter,
costulate to about 18 mm., then an injury, costate from about
20 mm. onwards. The costz are decidedly reclinate and nearly
straight on lateral area, sharply projected beyond small nodi, which
are situated on the periphero-lateral border. Suture-line simple.

Remarks.—This species is much larger than any Arnioceras
known to me in literature; but Mr. Tutcher has a fragment of an
Arnioceras from Radstock which would measure about 55 inches
(140 mm.) in diameter. The species is distinct from A. bodley?
(J. Buckman) by its more reclinate, wider-spaced ribs and by a
somewhat smaller umbilicus at the same diameter. It might be
suggested that the reclinate ribs were due to the injury in the
young stage, but it is evident that the specimen entirely recovered
from this, and was so little affected that it grew to an unusual size.
Mr. Tutcher has Radstock specimens of Arnzoceras with much
reclinate ribs. Also Quenstedt figures a form which has the same

302 MR. S. S. BUCKMAN ON (vol. lxxiii,

style of reclinate and well-spaced ribbing. Quenstedt’s specimen
is not, however, quite the same: it is the next step onward; its
smooth stage is evidently shorter, its whorl somewhat broader, and
its umbilicus rather narrower.

For dimensions of this and comparable species, see below.

History of figured specimen.—Out of a dark (phosphatic? )
limestone of the Lower Lias from Paulton, near Radstock (Somerset)
—purchased from a workman.

TABLE XVII.—PROPORTIONS: ARNIOCERAS FORTUNATUM AND LIKE FORMS.

62, 26, —, 54
Arnioceras fortunatum, DOV. — .seorewensesseseee = 80, | 23579 S6Cta see
121, 20, 16(17-+-), 60.

Arnioceras aff. fortunatum.
(Ammonites ceratitoides Quenstedt, xiii,8)’. F.49, 27, 17(21), 51.

Arnioceras bodleyi (J. Buckman).

(Ammonites bodleyi J. Buckman, xi, 7) ?... F.68, 25,0 18(20)e 56.
(Arietites semicostatus Wright, i, 4,5)° ... R74, - 245 ie 57.
(Ammonites ceratitoides Quenstedt, xiii, 10)1. F.76, 25, 17(19), 58.
(Arnioceras bodleyi S. Buckman)?* ......... S. 62, 25,0 anaes

CoRONICERAS BUCKLANDI (J. Sowerby).
1816. gee ae bucklandi J. Sowerby, ‘ Mineral Conchology’ vol. ii, pl. exxx
op. 69.

Mr. Tutcher has a large specimen from Keynsham, near Bath
(Somerset)—a topotype, for Sowerby’s ‘Bath and the neigh-
bourhood’ doubtless meant Keynsham. He gives the following
proportions, 8. 493, 26, 382, 55; and Sowerby’s figure, allowing for
foreshortening, I estimate to give much the same: his figure is
presumably reduced to about a quarter of the natural size.

Most interpretations of this species fail to allow for the great
thickness of whorl maintained to 20 or more inches in diameter.
See Chronological paper, p. 273.

Family DEROCERATIDA.

Genus Deroceras Hyatt.

DEROCERAS BISPINIGERUM, nom. nov. (P. 294, fig. 7.)

1903. Deroceras sp., S. S. Buckman, Q. J. G.S. vol. lix, pl. xxvii, figs. 5 & 6
(holotype).
1914, Bituberculate Deroceratid, Lang, Proc. Geol. Assoc. vol. xxv, p. 321. -
Remarks.—This name is for a species already figured in the
Society’s Journal but without trivial appellation. As Mr. Lang
has now found another example 37 mm. in diameter, with the same

1 <Ammoniten d. Schwabischen Jura.’

2 «Geology of Cheltenham’ new ed. 1844.

3 «Monogr. Lias Ammonites’ 1878.

+ Figured in ‘ Paleontologia Universalis ’ 1904, No.36,T!. The end of the
whorl, it should be noted with regard to figs. T!4, T!*, is somewhat swollen
with pyrites.

ei

part 4] JURASSIC CHRONOLOGY: LIAS. 303

mineral condition, as he has obtained it im sztw (which fixes the
horizon for the first specimen), and, as it marks a definite horizon
in the Raasayan, a full name is desirable.

This species is comparable with two of Geyer’s, but differs from
his Aigoceras precursor, with which it shares the radial linear
ornament, by whorl-shape—whorl widest at the periphery—the
retention of the inner row of spines, and yet having less whorl-
inflation. His Ayoceras bispinatum is separable by having a more
rounded periphery, a different whorl-shape, more approximate
spinicoste, and less differentiation‘in spines of the two rows. For
references and proportions, see table below.

History of the types.—Holotype, from a bed of Lias yielding
pyritized fossils in the neighbourhood of Lyme Regis (Dorset )—
purchased there. Paratype, ‘in place, bed 94, about 4 feet above
Oxynotus bed. About 800 yards west of Westhay Water, east of
Charmouth,’ Dorset; Coll. W. D. Lang, No. 2578. See Table V,
facing p. 267.

TABLE XVIII.—PROPORTIONS : DEROCERAS, ETC.

Deroceras bispinigerum, holotype ............ S. 55, 28, 35, 50.

Do. do. Pata PES “ys. e yaeme 8.37, 28, 34, 49,
F. 48, 32, 38, 45,
P50; 26, 30, 49.

~

Aigoceras bispinatwm Geyer? ..............604. F. 55, 30, 305 46.

Aigoceras precursor Geyet! ........ A Ai Oe os

Genus MtcropERocERAS Hyatt.

MICRODEROCERAS DEPRESSUM, nom.-noy. (Pl. XXX, figs. la & 10.)

1867. Ammonites birchi Dumortier (non J. Sowerby), depressed variety, ‘ Bassin
du Khoéne’ vol. ii, pl. xli, figs. 1, 2, p. 130.

Remarks.—This name applies to the shell figured by Dumortier,
which he notes as different from that figured by Sowerby and
A.dOrbigny. He calls it a depressed variety, and that appellation
is retained in the present trivial name. The holotype, however, is
an English specimen which agrees with Dumortier’s shell, except
in one respect—Dumortier’s shows peripheral radii (costule) nearly
straight and parallel; in the English shell the radii connecting
tubercles are nearly straight, but the intermediaries have rather
more forward bending. j

The stouter whorls with a more pronounced umbilical wall, a
slightly shorter smooth stage, and a small increase in the number
of tubercles to a whorl in middle age, are features of distinction
from Ammonites birchi.

Proportions are given below (p. 306).

History of the specimens.—Figured specimen (No. 1280)
from blue Lias, excavation for reservoir of Bristol Waterworks,
Barrow Gurney (Somerset), presented by Mr. J. W. D. Marshall.

1 ¢Ceph. Hierlatz’ Abhandl. k. k. Geol. Reichsanst. vol. xii (1886) pl. iii,
fig. 27. 2 Ibid. pl. iv, fig. 4.

304 MR. §. S. BUCKMAN ON | vol. Ixxin,

Another example, about same size and matrix, and a smaller
specimen with matrix decomposed to light yellow, presented by the
late KH. Wilson, F.G.S. Another example, matrix soft, decomposed
to light blue (purchased) : all from the same place. And see note
to next species.

MIcRODEROCERAS SEPTIGERUM, nom. nov. (Pl. XXX, figs. 2a
& 26.)
1844. Ammonites birchiti J. Buckman pars (non J. Sowerby), ‘Geology of
Cheltenham’ new ed. p. 88.

Description.—Serpenticone; platy-perpachygyral, perlatum-
bilicate to pachygyral latumbilicate ; bituberculate; septitubercu-
late; periphery flatly rounded, subarci-costulate. |

Remarks.—This is an inflated development of Ammonites bir thi
by way of the last species (JZ. depressum), but it has not attained
to the inflated proportions of the next species (JZ inflatum),
though it has passed that species in the differentiation of the outer
tubercles compared to the inner—the character seen at a later date
in Deroceras (D. bispinigerum, p. 302) and later still carried to
unituberculation.

This species is best understood by comparison with Jf inflatum.
Its thickness is some 7 per cent. less at 64 mm. diameter, and the
periphery is somewhat flatter. The ornament is similar, but the
spinicoste are about 50 per cent. wider apart, and the outer row
of spines is shown by the septate areas to be more developed and
more differentiated from the inner. ‘The conspicuous septate areas
which are somewhat B-shaped suggest the trivial name: the outer
(top) loop is broadly, and the inner narrowly, elongate with a thin
connecting area—thus the partition extended not only under the
spines, but also under the connecting rib.

Proportions are tabulated below (p. 306).

History of the figured specimen.—The original label,
skeleton printed, on the specimen reads: ‘Name A. Bzrechiz,
Loe. Lias, Cheltenham, Col. by J. Buckman, —the words in italies
filled in in his handwriting. ‘The matrix is light blue with erinoid-
stems, small gastropods, small lamellibranchs, and broken organisms.
See below, p. 312.

_Note.—Since this paper was written I find that I have over-
looked another of my father’s specimens of Ammonites birchii
(S. B. coll. No. 2115). It has a quite different matrix—blue and
pyritic; but bears the same label, which thus may mean ‘close to
Cheltenham’ rather than ‘Cheltenham district’: see below, p. 312.
Its proportions are 8. 72, 28, 29 (81), 49; 8.114, 26, 28 (29), 51.
Spines are approximate and somewh 58 on last row of
outer whorl. It is an example of MWicroderoceras depressum, see
above. On one side is an impression of a portion of «another
iWicroderoceras, of about the same size, showing obsolescence of
spines, of interest in connexion with remarks below, p. 307. |

part 4] JURASSIC CHRONOLOGY: LIAS. 305

Mrcroperoceras INFLATUM, sp. nov. (Pl. XXVIII, fig. 3;
eee EX fic.’ T:)

Description.—Serpenticone; platy-perpachygyral, perlatum-
bilicate to subplaty-pachygyral, perlatumbilicate; bituberculate,
septituberculate ; periphery rounded, subarcilineate.

General details.—A much inflated development of Ammonites
birchi, beginning with a similar smooth stage, rapidly developing
bituberculate, whereof presently the outer row becomes rather
stronger than the inner. Beneath spines and connecting rib there
is a septum of subspatulate shape. Close-set hair-like lines occupy
the interspaces and the arching periphery, which latter they cross
with a slight forward bend.

Distinetion.—The proportions (see below, p. 306) distinguish
this from preceding species: it attains at one time an inflation of
50 per cent. of the diameter, but afterwards declines as if com-
mencing to return to the bzrchi style.

Remarks.—According to indications of test on the periphery
the specimen had another complete whorl at least. Its diameter
may be roughly estimated, from the fact that from the centre to
the farthest periphery is 55 per cent. of the diameter of the last
whorl present: therefore the maximum radius becomes 45 per cent.
of the diameter of the next half-whorl, which being thus ascertained,
its maximum radius becomes the basis, roughly 45 per cent. of the
second half-whorl. The indications of test on the periphery give
- umbilical width of 54 and 62 per cent. of the respective diameters
(164 mm. and 198 mm.) so ascertained: these umbilical widths are
perhaps too great, because possibly the 55 per cent. basis was not
maintained; and so the diameters are perhaps understated—the
whorl becoming thinner and broader. The umbilicus is expanding,
as the inner line is leaving the outer spine-line.

As this specimen may be reckoned to have attained a diameter
of 200 mm. or more, it was, considering its inflated proportions, alto-
gether a much larger growth, had a greater bulk, than Ammonites
birchi, though A. d’Orbigny does record a diameter of 240 mm. for
his specimen. The species now described possibly represented the
acme of development in MWicroderoceras; but some of the later
Derocerates far exceeded these dimensions-—some of the Radstock
giants collected by Mr. Tutcher and myself from the lechenbyi
bed attaining to 860-380 mm. (14-15 inches) in diameter.

History of the figured specimen.—From hard light-blue
Lias weathered to light yellow and soft [white in places ?], from
excavations for reservoir of Bristol Waterworks, Barrow Gurney
(Somerset )—purchased.

MiIcRODEROCERAS RHODANICUM, nom. nov.

Ammonites heberti Dumortier (non papel): ‘Bassin du Rhone’ vol. ii (1869)
pl. vii, tigs. tae 66.

Oos. Gs. No. 292. 2 3B

306 MR. 8. S. BUCKMAN ON [ vol. Ixxiui,

which is not Oppel’s species, for that was founded on Ammonites
brevispina D’Orbigny (non Sowerby). Its proportions are dif-
ferent. Dumortier’s is a thicker form; D’Orbigny’s is a further
stage on 1n compression and degeneration: it gets back to the
smooth stage.

TABLE XIX.—PROPORTIONS : MICRODEROCERATES.

1. Microderoceras birchi (Sowerby).

(Ammonites birchi Sowerby, pl. cclxvii)! F. 204, Zed ynesOsenle ae ens
(Agoceras birchi Wright, pl. xxiii) *... F.160, 22, 23, 58.

{ Microderoceras depressum, nov.
| (Holotype, Barrow specimen) ......... Soar 29, 32) Al.
(Ammonites bircht Dumortier, xli, F.197(94), - 28; 29, ol.
Dsl SO) Se ge ee eas: earn eae 28, al, 50.

2.4 Microderoceras septigerwm, nov. :

(Ammonites birchi J. Buckman) ...... S. 42, 30, 43, 45.
et 89, 30, AO, 42,
Microderoceras inflatwm, nov. ............ { See a= 2 uss
ee : S. 194) al 38, 4A,

( Microderoceras bispinatwm (Geyer).
(Agoceras bispinatum Geyer) ......... F. 59, 30, 30, 46.

Microderoceras rhodanicum, nov. ...... Fy 3b; 32, —, 4A,
(Ammonites hebertt Dumortier). SOR 31, 42, Bile
Be shite 34, —., 45.

T.. 74, 32, 29, 45,

3.4 Microderoceras heberti (Oppel). .
(Ammonites a ee one Ea ae F. 74(47), 32, 24, A5.
tb:ea'p-d aap eae AR 140(90), 32, 24, 47.
T.140, 31, 25, AZ.

Microderoceras roberti' (Hauer).
\ (Ammonites roberti Hauer, iii)® ...... At Oe 36, 23, 40,

Microderoceras septigerum and MM. inflatum are species suffi-
ciently alike to make it probable that they indicate beds of the
same date. More will be said on this point presently (p. 311).
Curiously enough, I have not found in hterature anything really
like these inflated forms. The most comparable species are
Aigoceras precursor and di. bispinatum ‘Geyer, possibly of
basal Raasayanh, Deroceras bispinigerum (p. 302), low in Raasayan,
Microderoceras rhodanicum (p. 805), presumably top of Raasayan
(leckenbyt). All differ in proportions from the inflated forms,
as Tables XVIII & XIX show.

The placing of certain bituberculate species to Wicroderoceras
and others to Deroceras must be regarded as conventional. I am
not prepared at present to state the difference between them: the
study necessary for that might delay this Appendix for several
years ; and it is a biological matter.

This, however, may perhaps be said: various branches of Wcro-
mie: as may be noted :—

. The birchi set-—the A. bir chi of Sowerby, Wright, D’Orbigny,

1 «Mineral Conchology.’ 2 “Monogr. Lias Ammonites.’
5 * Bass. Rhone,’ vol. ii. 4 * Pal. frang.: Terr. Jur. Céph.’
> * Capric.’ Sitzungsber. k. Akad. Wissensch. Wien, vol. xiii (1854) p. 94.

_

part 4] JURASSIC CHRONOLOGY: LIAS. 307

cand others with the forms to which Quenstedt has given names—

M. nodosissimum, M. enode,? M. gigas.8 In this set catagenesis
to smooth occurs without an inflated stage and without much
umbilical contraction.

2. The inflatum set:—This starts from JZ. depressum, an
offshoot of the birchi set while in its prime, and it continues
anagenesis until a maxunum whorl-inflation of about 50 per cent. is
reached, after which decline sets in. Between JZ. depressum with
32 per cent. of inflation and JL. inflatum with 50 there is evidently
room for another species: J/. septigerum comes here, but does not
quite satisfy as a link, because of its more distant ornament.

The heberti series:—This branches off from J. depressum,
perhaps, or some morphic equivalent; but it is a series much later
in date. It goes through an inflated, period similar to the last,
running up to 42 per cent. Then it rapidly declines, broadens and
compresses the whorl, becomes smooth, and presumably ends off in
a smooth subplatycone series—such as Ammonites roberti Hauer,*
Reynes,? A. lorioli Hug,® A. steinmanni Hug,’ A. plumarius
Dumortier.* Specimens ‘with the catagenetic characters of those
just named are in Mr. Tutcher’s cabinet from about Zeck enbyt of
Radstock: they have a bituberculate Microderoceratan stage in
eo whorls and a Microderoceratan suture-line.

The Deroceras stock:—This would branch like the last from
some morphic equivalent of J/. depressum, an early stage being
represented by Deroceras bispinigerum. This line does not go
through an inflated stage while bituberculate, but it loses this
character early, dropping the inner row of spines, compensating by
enlarging the outer row and broadening the periphery, producing
in some cases in the unituberculate stage not true inflation but
forms broad in the venter with much divergent sides—a method
of producing cadicones ultimately. But there must be several
lineages now combined in Deroceras-—-and in some of them the
morphogeny must be complicated, with apparently. alternations of
anagenetic and catagenetic stages of ornament.

(c) Geological Inferences from the Described Species.

Domerian.—Lepfaleoceras is interesting for its rarity. Among
the hundreds of British Domerian (Marlstone Series) ammonites
that have passed through my hands, I remember only the three
specimens now dealt with ; and I can recall but few cases of similar
Hildoceratids.? Mr. Spath says that ‘even in the British Museum
collections Mesohassic Hildoceratids are almost unrepresented.’ 1°

1 ¢Ammoniten d. Schwabischen Jura’ xviii, 7, Am. birchi nodosissimus.

2 Ibid. xviii, 9, Am. birchi enodis.

% Ibid. xviii, 13, Am. birchi gigas. + Loe. jam cit.

> ‘Mon. Amm.’ pl. xxx, figs. 13 & 14 (copy of Hauer).

6 Abh. Schweiz. Pal. xxvi (1899) pl. viii, fig. 1 & pl. ix, fig. 2.

7 Foid. pl. ix, figs. 1 & 2.

8 «Bassin du Rhone’ vol. iii (1869) pl. xvii, figs. 1-3.

» * Exeluding Sequenziceras. 10 Op. jam cit. p. 547.

2B2

308 IR. §. §. BUCKMAN ON [vol. lxxiii,

te

Such Hildoceratids find their home in the Mediterranean area:
whether their rarity here is due to stratal failure or inequality
of zoological distribution is for future work to determine.

An attempt to ascertain the position of Leptaleoceras in the
Domerian may be made by comparison of its matrix with that of
other Ammonites. Taking the Gloucestershire area first—the matrix
of A. nautiliformis J. Buckman,! from a neighbouring Marlstone
eminence, Alderton-Dumbleton, a few miles north of Gretton, is
light blue, compact, arenaceo-caleareous (micaceous ?) non-oolitie—
very suggestive of the ‘bluish gray caleareous grit’ mentioned
for a bed of ‘ Marlstone’? (lower Domerian, below the Rock-Bed).
The matrix of Leptaleoceras is blue, less compact, caleareous and
shelly. That of specimens of Amaltheus armiger? (Am. amaltheus
spinosus Quenstedt, pars) from Gretton and Alderton is feebly
blue, oolitic, very shelly; while that of Paltopleurocerates from
the latter place varies from somewhat similar, not so shelly, to
yellow, not shelly, not oolitic.

On the principle that the blue colour and the arenaceous
character are indices of lower beds, the following Gloucestershire
sequence may be surmised :—

5. Paltopleuroceras.

4, Amalthei (spinous forms).

3. Leptaleoceras.

2. A. nautiliformis.

i; P

In regard to South Petherton, colour fails to make distinction
between the matrices of such ammonites: all are a yellowish,
more or less ironshot oolite, with only the distinction of larger
browner limonitic grains in the cases of the Amaltheids. The
absence of blue colour and of micaceous grains with presence of
ironshot oolite seems to show that all come not lower—and it may
be in, the Rock-Bed—equivalent to Bed 4, 8 to 12 feet thick, of
Woodward’s section from the neighbourhood #—this Rock-Bed
being some 150 feet from the base of the Marlstone Series of
which the lower 100 feet is described as ‘ blue and grey micaceous
marls.’ In this Rock-Bed it may be assumed that the Amaltheids
occupy the higher part, and the other ammonites the lower; and
now that the Gloucestershire district has suggested somewhat of a
clue, perhaps the differentiation of the Somerset Rock-Bed into
zones can be made: there is room enough for several, and the need
is ohvious.
This interpretation with regard to nautiliformis and its matrices

would mean, if correct, that in the Ilminster district of Somerset
the Marlstone Rock-Bed began earlier than in Gloucestershire ;

1 * Yorkshire Type Ammmonites’ 1911, No. 37.

2 «Geology of Cheltenham ’ new ed. 1844, p. 38, Bed 2.

3 ‘Yorkshire Type Ammonites’ 1911, p. 25d. As one finds this and like
spinous Amalthei labelled Am. spinatus on occasion, a clue may be afforded

to some old records.
+ <TLias of Engl.: Jur. Rocks’ vol. ii, Mem. Geol. Surv. 1893, p. 202.

part 4] JURASSIC CHRONOLOGY: LIAS. 309

but much variation in this respect may be expected as well as, the
more minutely subdivision is carried on, a great increase in local
non-sequences.

The position of the Leptaleoceras and A. nautiliformis horizons
in regard to the faunal sequence discussed in the stratigraphical
portion of this paper (p. 260), may be surmised to this extent—
they are pre-gzbbosa —a spinous species near to, perhaps as used
by Monestier including, Amaltheus armiger. Whether they are
_pre- or post-algovianum as now restricted is uncertain; but it
may be surmised that they do not correspond to this algovianum
horizon, because the localities yielding the respective faunas seem
to be geographically separate.

Evidence for other pre-gzbbosa horizons in this country and
their relation to the Mediterranean sequence will chiefly depend on
certain Amalthei, Lytocerata, and an occasional Hildoveratid. ‘On
the Dorset Coast very low down in the Domerian—in the strata just
above the Three Tiers—are Amalthei of the clevelandicus pattern,
and the same occur low down in marls at Lightpill, near Stroud
(Gloucestershire). Large Amalthei of the stokesz pattern occur in
sandy strata at South Petherton—perhaps the A. margaritatus of
Woodward’s Bed 21; but whether this is pre- or post- -algovianwm
in its restricted sense is uncertain. The or iginal Ammonites stokest
came from the Dorset Coast; but there is the same doubt about
its position: one can only judge from the colouring of Sowerby’s
plate that it is from blue marls. Fine Lytocerates occur in the
Marlstone Series at Dudbridge, near Stroud, and at two horizons
on the Dorset Coast: there are various species, recorded incorrectly
as A. fimbriatus. Day cites the good specimens from his Margari-
tatus stone? where I have found them, and he places others lower.®
Whether the Dudbridge species are on the same horizon as either
of the Dorset species cannot yet be said: there may be three
horizons.

All this evidence, faulty though it may be, seems to suggest
that there are the following pre-gibbosa horizons in the English
Domerian to deal with :—

Leptaleoceras.

Spherocones (A. nautiliformis).
Amalthei (of stokesi pattern).
Sequenziceras (and small Amalthei).
Lytocerata.

Amalthei of clevelandicus pattern.
Lytocerata.

These ‘divisions may not all be separable, and it is not claimed
that they are in correct descending order; but a table of some sort
is required as a preliminary to making out our home sequence.
Only when that is understood will it be possible to correlate with
the Mediterranean sequence, and bring all into one hemeral time-
scale.

1 Loc. cit.
2 Q. J.G.S. vol. xix (1863) p, 292. > Toid. p. 291.

310 MR. S. S. BUCKMAN ON [ vol. Ixxii,

Hwiccian—Wessexian.—The importance of the giant Acantho-

leuroceras is that during considerable collection in the brickyards
of the Cheltenham district nothing at all approaching the size of
this specimen and of another fragment, Acanthopleuroceras gigas
(Quenstedt),! nearly as large, rewarded my efforts. These specimens
were found by the late Rev. Dr. F. Smithe, F.G.S., during the
making of the Banbury & Cheltenham Railway at Leckhampton ;
and the interence is thata stratum different from any of the brick-
yard exposures must have been cut through. Whether the stratum
belongs to any of the Acanthopleuroceras horizons discovered by
Mer: Lang on the Dorset Coast, or whether it is distinct from them
is a point towards which the attention of future workers should be
directed.

The local distribution of Acanthopleuroceras in the Cheltenham
district seems to indicate two separate horizons, apart from the
horizon of the giant forms. Battledown near Cheltenham yields
mainly thin species; Leckhampton Station near Cheltenham and
Hueclecote near Gloucester yield chiefly stout-whorled species.
Further afield Northamptonshire and Radstock yield the thin
species—solely, I think, more commonly at any rate. Hitherto
these dAcanthopleuroceras-yielding strata have been reckoned as
all in the same zone, but it is now evident that more investigation
is required.

In the Cheltenham district a great variety of Acanthopleu-
rocerata are found, but rarely otherwise than as body-whorl
fragments, which makes their specific identification difficult.

T cannot call to mind anything in literature of the size of
the large Acanthopleuroceras (260 min.). Quenstedt’s A. gigas
(pl. xxxv, fig. 14) I estimate at about 170 mm.; his ‘largest
fragment’ (fig. 15) may go up to 200 mm.: the Leckhampton
fragment—a body-whorl—reaches 244 mm. in diameter, however.
Dumortier’s Ammonites flandrini* measures 202 mm.; but this
is a species of quite a distinct type, special perhaps to the South of
France. Wiirtemberg, then, is the only area at all congruous with
Gloucestershire in regard to these large forms ; and it would seem,
if these large forms occupy a distinct horizon, that this horizon
has been preserved in areas limited and isolated geographically.

Raasayan.—Deroceras bispinigerum marks a Deroceras hori-
zon below the main outbreak of Echiocerata. It is interesting as a
representative of the bituberculate ancestor of the unitubereulate
armati, and shows the obsolescence of the inner row of tubercles.

Deiran.—The species of Radstochiceras and Gleviceras are
chosen as representatives of the faunas of the Radstock and
Gloucestershire Oxynotoid horizons, now separated from the oxyno-
tum horizon; but there are several other species in the latter area

1 « Ammoniten d. Schwabischen Jura’ pl. xxxv, figs. 14 & 15.
> * Bassin du Rhone’ vol. iii (1869) pl. xiv.

part 4] JURASSIC CHRONOLOGY: LIAS. (ger "yeas

and quite a considerable number in the former which require investi-
gation: they do not necessarily belong to the present genera. In
fact, the Oxynotoids appear to represent the catagenetic terminals
of many different lineages, of which the majority came into view
suddenly in the European Deiran without any ancestry. Only
Ammonites oxynotus Quenstedt, and A. oxynotus Dumortier, two
quite different species, seem to have traceable ancestors—the former
being connected with a tuberculate! and the latter with Arvetites
ot the fowleri-collenottii pattern.”

The placing of the Radstock Oxynotoid fauna later than the
Gloucestershire one ( Gleviceras) is a surmise not yet proved; but
their difference in species shows that they are distinct in date.
To place the Radstock fauna before the Gloucestershire one would
involve the supposition of another non-sequence in Gloucester-
shire.? Gleviceras belongs to a’ distinctly higher horizon than the
oxynotum beds in Gloucestershire; but, if that were not known,
the absence of Gleviceras from Wiirtemberg, where 4. oxynotus is
conspicuous, would be presumptive evidence of a difference of date.

It is notable that no specimens of the Radstock Oxynotoid fauna
are figured by Quenstedt, and only two examples which have the
aspect of constituents of the Gleviceras fauna—Ammonites gui-
balianus Quenstedt, ‘Ammoniten d. Schwabischen Jura’ pl. xxvi,
figs. 3 & 4—not from any oxynotus locality, and from a higher
horizon (lias y). Pompeckj) has named them Oxynoticeras
paradoxum, and places them in yamesoni | leckenbyi?| zone. They
have neither suture-line nor ribbing of Gleviceras ; and not the
ribbing of Gudbaliceras. Present experience would suggest that
their position may be due to derivation.

Mercian—Lymian.—The Barrow Gurney fauna (dArvetites
turgescens, p. 296, and Microderoceras inflatum, p. 305) is con-
gruous with that of Bredon (Worcestershire), certainly as regards
the Arietites and presumably with regard to the MLicroderoceras
(see below, p. 312). But this special fauna is not known from
intermediate areas, is absent from Dorset: and also from Yorkshire
so far as my experience goes. Dumortier shows a partly com-
parable Wicroderoceras fauna, but not Arietites; Reynés shows
Arietites, but not any MWicroderoceras of the style required.*
Quenstedt shows nothing comparable.> A first inference may

1 See ‘ Yorkshire Type Ammonites’ i (1909) p. 7b.

2 To these may now be added Gleviceras, see above, p. 292.

3 See p. 272.

4 But Reynés is unsafe: his specimens are from many areas; and see p. 322.

® One can in the main only go by what is published. I know from my own
and other collections that a great mass of new material is unpublished. I
write with some knowledge of that, although memory necessarily has its limi-
tations in this respect, owing to the difficulty of fixing new fornis in one’s mind
because of their lack of names. Even photographs help little without names
to serve as tags for the memory. But, if similar conditions obtain on the
Continent, then of course the statements made above might be invalidated.
On the other hand, Continental Ammonitology is far more complete in many
areas than is the British.

312 MR. S. S. BUCKMAN ON [vol. Ixxiii,

certainly be drawn, that the special Wicroderoceras—Arietites fauna
did not oceupy the horizon of either turneri or birchi, otherwise
they should be found in the areas where those species occur; and a
second inference may more tentatively be made—that the IWiero-
deroceras and Arietites did not occupy the same horizon.

If it were possible to proceed on strictly biological lines, then a
solution would be quite easy ; but biological and geological position
are not always in accord: ‘Xipher oceras above Microderoceras,
Paltopleuroceras later than Amaltheus, Hildoceras after Har-
poceras in geological position, when they should respectively precede
biologically. But these are distinct genera: in regard to species,
Harpoceras exaratum below H. falciferum, Hildoceras bifrons
below H. semipolitum, Arietites turneri below A. brooki, and
this again much below A. denotatus, show very well the agreement
of geological position and biological development.

In the present case the assumption of the agreement of bio-
logical and geological position is all that there is to go upon. No
record of the Barrow exposure seems to have been made. Speci-
mens were very few, so I understand, for the great area opened
up; and what have been saved were only the finds which the
nayvies took the trouble to bring home with them.

The matrix of the Barrow Gurney exposure is a hard blue Lias,
which weathers or decomposes to a soft white, almost chalky
substance. This matrix is quite unlike any other with whicu I
am acquainted in the South-West, and it would serve well to
distinguish Barrow specimens. I find, however, that some speci-
mens in my father’s Cheltenham collection show a similar matrix,
perhaps rather more cream-coloured; and Wright says of his
Arietites turnert | A. aff. turgescens |:

‘The specimen figured was collected from a light-coloured clay and limestone
in the deep cutting of the Bristol & Birmingham Railway, near Bredon
[Worcestershire |, associated with A. Bonnardii, dOrbigny, [| Arietites aff.
plotti (Reynés) |, A. semicostatus; Y. & B., [ Arnioceras bodleyi (J. Buckman)}|,
and several other mollusca, with many fragments of the stems and side
arms of Pentacrinus tuberculatus, Miller, and Cidaris Edwardsii, Wright.’ !
The character of matrix and the remarks about the Pentacrinus
well fit the condition of A. birchi J. Buckman (MWicroderoceras
septigerum) ; and, though it is labelled Cheltenham, yet Bredon
is quoted as a locality for A. birchi,? and I suspect that the
label ‘Cheltenham’ possibly denoted in such cases ‘ Cheltenham
district,’ just as ‘Vale of Gloucester’ was possibly used to include
Bredon. Judging by the light-coloured matrix it may be suggested
that from Bredon came my “father’s holotype and various paratypes
of Ammonites halecis, the figured specimen and another with
perhaps a third of ,his A. erugatus (Agassiceras), the specimen
he called A. costatus (Agassiceras), two paratypes of his A. bodleyz,
and the present holotype of Wicroderoceras septigerum.

1 Proc. Cotteswold Nat. F. C. vol. iii (1864) p. 177, repeated in ‘ Monogr.
Lias Ammonites ’ 1881, p. 293; see below, (e) p. 318.
‘Geology of Cheltenham ’ new ed. 1844, p. 88.

part 4] | JURASSIC CHRONOLOGY: LIAS. 313

Turning now to the biological argument—the biological facts
are: 1, MWicroderocerata which are developments of IZ. birchi;
2, Arietites which are developments of A. turneri: the geo-
logical facts are a special matrix for these developments and the
position of I. birchi—A. turneri on the Dorset Coast: the geo-
graphical facts are the presence of the special fauna (and a distinc-
tive matrix) only at isolated places in England, the absence of
the fauna from well-known, much-searched localities, and its very
limited range upon the Continent.

On these various grounds it may be suggested that the full
Mercian—Lymian sequence, instead of being

. Arietites brooki,
. Arietites turneri,
. Microderoceras birchi,

HI bo 0

is rather
d . Arietites brooki,

. Arietites turgescens (+A. aff. twrgescens),

. Arietites turneri,

. Microderoceras inflatwm+M. septigerum+ M. depressum,

. Microderoceras birch.

re bdo co Ot

This involves the supposition of non-sequences between bzrchz
and turneri and again between turneri and brooki, on the Dorset
Coast and over other wide areas; but it may be unnecessary to
suppose a non-sequence at Barrow for, I think, twrneri forms
were found there. Then the absence of Arietites brooki and
Microderoceras birchi from Barrow might be explained by
supposing that the excavation began below the brooki bed, and did
not go so deepas bzrchi; but other explanations are possible: the
area just north of the Mendips was in constant movement.

Another suggestion may be made: that the sequence is

. Arietites brooki.

. Arietites turgescens.

. Microderoceras inflatum.
. Arietites turneri.

. Microderoceras birchi.

re po CO & OF

This would require only one non-sequence at Lyme Regis, and
would meet the case if the true A. turnevi has not been found at
Barrow. This sequence shows faunal repetition such as that found
in the Raasayan and in the Hwiccian-Wessexian. Nos. 8 and 4
might be called the Barrow Beds. .

In the first case the division between Mercian and Lymian
would be drawn between 2 and 8. In the second case, however, it
would seem desirable not to draw it between 2 and 1 as proposed
earlier in this paper (pp. 271, 274), but to draw it below 1, to
prevent divorce of the Microderocerates.

In the case of Bredon there is evidence that earlier faunas were
uncovered than at Barrow; and there is reason to suppose that
they were found in the peculiar chalky Lias, also that there was

314 MR. S. S. BUCKMAN ON ‘{vol. lxxiii,

not a non-sequence due to lack of turneri beds, for the species
cited by Wright as A. bonnardii is possible evidence for them.

The true bzrchz beds were presumably present—on the supposi-
tion that Wright was referring to the true bivchi or a very near
form, and not to ALicroderoceras septigerum, when he says ‘I have
several specimens | of Aigoceras birchii| which were collected from
the railway-cutting near Bredon.’!

The evidence for an dArnioceras fauna being there and oceurring
in a chalky matrix has already been given; the same details refer
to Agassiceras, see above, p. 312, to which may be added that
Wright figures a large Agassiceras from Bredon.?

Lymian.— Arnioceras is in the main a genus easy to recognize
from other Arietide, with its straight sharp ribs and smooth inner
whorls: the only difficulty may be with body-chamber fragments.
But the species of Arnioceras are numerous and not easy to
separate ; yet for the detailed work now required such recognition
will be necessary, in order to see what the succession of species is
in time. Old records, where the various species of Arnioceras are
just cited as Ammonites semicostatus without further distinction,
serve but a limited, and it may be a somewhat misleading, purpose.
For there is reason now to be sceptical whether the placing as
isochronous of semicostatus beds—that is beds containing Arnio-
cerata—is really correct. Faunal repetition and non-sequences
mav have been overlooked.

Of the species now figured the characters are sufficiently obvious:
Arnioceras flavum is a carinate smooth form, A. anageneticum
shows the beginning of ribs, A. fortunatum is almost wholly ribbed,
disting wished by its markedly-reclinate somewhat distant coste.

Thirteen species of Arnzoceras are enumerated from the Whitby
district of Yorkshire,? and (speaking from memory) all of them are
more or less distinct from the species now figured. In Lincoln-
shire there is a rather heavy form with strong ribs usually called
Ammonites geometricus Oppel, if and when ‘distinguished from
A. semicostatus. ‘There may be more than one species involved ;
but the shells are of very distinct character. This form (or these
forms) are constant among all series of Lincolnshire Lower Lias
ammonites; but from other British localities they are lacking, or
only occur exceptionally.

From the Cheltenham district Avnioceras bodleyi seems to be
the special form; it is not quoted from Yorkshire in the list cited
above; it occurs in Wiirtemberg, but can hardly be usual there,
for only a poor fragment is figured by Quenstedt, see p. 302.

Arnioceras fortunatum is known to me at present only from

1 Proc. Cotteswold Nat. F. C. vol. ii (1864) p. 179, repeated in ‘ Monogr.
Lias Ammonites ’ 1882, p. 333 ; and see below, (e) p. 319.

2 Proc Cotteswold Nat. F. C. vol. iii (1864) pl. ii, fig. 1, refigured in ‘ Monogr.
Lias Ammonites’ 1878, pl. viii, figs. 1, 2, Arietites sauzeanus: below,
(e) p. 321.

3 <Geol. Whitby’ 2nd ed. Mem. Geol. Surv. 1915, p. 98. :

part 4] JURASSIC CHRONOLOGY: LIAS. 315

Radstock, but Quenstedt figures an approximate form. 4. anage-
neticum 1s a Dorset shell: something similar is figured by Hyatt
from Semur!; but nothing like either is figured from Wiirtemberg.

The distribution of the smooth forms is interesting. Yorkshire
yields an angulate species and Dorset a carinate one, while no
smooth forms are recorded from the Cheltenham area. Neither
of the English smooth forms is shown for Wiirtemberg nor Semur :
both. yield less advanced angulate and carinate forms, and the
former a more advanced carinate, see p. 299. The Rhone Basin
seems to lack smooth forms altogether.

It is for future work to determine, on the one hand, whether
such differences are due to incompleteness of records and collections
or to want of discrimination ; on the other hand, whether they are
due to chronological (stratigraphical) or geographical causes.

Arnoceras fortunatum is interesting for its size. Now bigness
seems to be a character of the ammonites of the Radstock district
at several dates of the Lias. Roughly speaking, much the largest
British examples of <Arnioceras, the Oxynotoids, KHchioceras,
Deroceras, Phricodoceras, and Uptonia are all from the Radstock
district, and yet its remarkable ammonite fauna is almost unknown
in British literature. To these may be added, from the neigh-
bourhood, Vermiceras 18 in. (Wright, Monogr. p. 273, Arietites
conybearer), the most massive Coroniceras (C. bucklandz), the
most bulky IMtcroderoceras, the largest Arietites. In some cases
this phenomenon of local bigness is due to the presence in the
district of special strata which have presumably been destroyed in
other areas; but is this the whole explanation ?

I conclude this paleontological survey with the impression that
the principal need of British Jurassic stratigraphy at present is
palzeontological work—the figuring of the large amount of material
which has accumulated.

(d) Synopsis and Index Details.

Below is a Synopsis of newly-described or named genera and
specles—new names being in heavy type. ‘The index details
are given with the following contractions :—

T.d. 'Type-description, original description (protolog).

T.f. Type (original) figure (protograph).

Nom. When and where the present trivial name was given.

T.l. Locality which furnished the type.

Hor. Geological position—in words of original description, or
label.

Date, Age and hemera (7) as accurately as can be surmised.

Coll. In whose collection when described, or present resting-
place, if known.

Form. Proportional formula—that which seems most representa-
tive, if that of more than one size of holotype has been
given.

1 “Gen. Ariet.’ 1889, pl. ii, fig. 10, Arnioceras semicostatum Hyatt.

316 MR. 8. 8S. BUCKMAN ON [ vol. lxxiii,

The details so given refer to the holotype, or, in default, to the
lectotype only. Plate or page quoted without reference refers to
the present paper.

Acanthopleuroceras rursicosta. —

Tids* BPr286:

LT. f.v Pl, EXVIE, fig. 4.

T.t. Leckhampton, Cheltenham (Gloucestershire).
Hor. Middle Lias clays. © :'

Date, Hwiccian—Wessexian.

Coll. Author.

Form. 360, 28, 20, 48.

Avietites turgescens.

Pisa ee 2G:

Pof,, WP eX. digs 2 PAS XO sirens:
Tl. Barrow Gurney (Somerset).

Hor. Barrow Beds of Lower Lias.

Date, [| Mercian, post-turneri]. —

Coll. Author, No. 833.

Form. 171, 33, 32, 495.

Arnioceras anageneticum,

Pdiinv B: SOO:

Tap HEL Oe tia.

T.l. Lyme Regis (Dorset).
Hor. Lias Limestones.

Date, [Lymian, Arnioceras 7}.
Coll. Author, No. 728.

Form. 42, 27, 20(24), 51.

Arnioceras flavum.

Pegs. ees as

Taf. Pl. XXSCE ae 25

T.l. Lyme Regis (Dorset).
Hor. Lias Limestones.

Date, {Lymian, Arnioceras nj.
Coll. Author.

Form. 25,° 27, 20, 51.

Arnioceras fortunatum.

Ed. ° B30,

Pf... > Pls RAK te 4c

T.l. Paulton, Radstock (Somerset).
Hor. Lower Lias | phosphatic bed],
Date, Lymian, Arnioceras n.

Coll. Author, No. 936.

Form. 80, 238, 16(18), 57.

Deroceras bispinigerum.

T.d. S.S. Buckman, Q. J. G.S. vol. lix (1903) p. 460.
T.f. Ibid. Pl. xxvii, figs. 5 & 6.

Nom. P. 302.

T.l. [Charmouth |, Lyme Regis (Dorset).

Hor. Lias with pyrites.

Date, Raasayan, bispinigerum yn.

Coll. Author, No. 591.

Form. 55,' 28, 35, 50.

part 4] JURASSIC CHRONOLOGY : LIAS. 317

Gleviceras, genotype, G. glevense paratype (p. 289, Pl.
PX VIL “ig. 2).

Gleviceras glevense, holotype.

fo.) -P. 289.

ij Pl SX VU, fig, tl.

T.l. Cheltenham (Gloucestershire).

Hor. Lower Lias Shales [above orynotwm].
Date, [Deiran, Gleviceras 7].
Coll. Author.

Form. 128, 51, 26, 14.

Guibaliceras, Genotype, Am. guibalianus D’Orbigny
(p. 293).

Leptaleoceras, Genotype, L. leptwm holotype (p. 284).

Leptaleoceras leptum.

ag 2 285.

Pep sel. MX VI, fie. 1.

T.l. South Petherton (Somerset).

Hor. Middle Lias Marlstone { Rock-Bed].
Date, {Domerian, pre-gibbosa |.

Coll. Author, No. 1113.

Form. 66, 24, 16, 52.

Microderoceras depressum.

idan k. 303.
ip Ply RX, fig. 1.
T.l. Barrow Gurney (Somerset).
Hor. Barrow Beds of Lower Lias.
Date, {Mercian—Lymian, post-birchi].
Coll. Author, No. 1280.
Form. 75, 29, 32, 47.

Microderoceras inflatum.

Wed. OP F05.

Pye Pls XXVIII; fie. 3'; Pl. XXX, fig, 1.
Tl. Barrow Gurney (Somerset).

Hor. Barrow Beds of Lower Lias.

Date, {Mercian—Lymian, post-birchi].

Coll. Author, No. 1281.

Form. 64, 34, 50, 465.

Microderoceras rhodanicum.

T.d. Dumortier, 1869, vol. iii, p. 66, Am. heberti.

Pn TOs el. Vill, Ut. o.

Nom. P. 305.

T.l. Saint-Fortunat, South of France.

Hor. lias moyen, zone a la belemnites clavatus, Couches
- & Am. armatus.

Date, [| Raasayan, leckerbyi n ].

Coll. Dumortier.

Form. T.74. 32, 29, 45.

318 MR. 8. S. BUCKMAN ON [ vol. lxxiii,

Microderoceras septigerum.

T.d. P. 304.

OP fe PN, ORI Hie

Loc. Cheltenham | District], Gloucestershire [ Bredon,
Worcestershire ].

Hor. Lower Lias Shales [ with Pentacrinites ].

Date, {Mercian—Lymian, post-birchi].

Coll. Author, No. 688.

Form. 89, 35, 40, 42.

Radstockiceras, Genotype, &. complicatum holotype
(p. 287).

Radstockiceras complicatum, ©

EOL, MEERA ¢

Tf esl ROO V Mile

T.l. Radstock (Somerset).

Hor. Lower Lias with Oxynotoids.
Date, Deiran, Radstockiceras ».
Coll. Author, No. 2768.

Horm. 186, 54, 25, eLL:

Victoriceras, Genotype, dim. victoris Dumortier
(p. 293).

(e) Concerning some of Wright’s figured Ammonites.

To Vol. iii of the ‘ Proceedings of the Cotteswold Naturalists’
Field Club,’ parts 2 & 3, published in the years 1864-1865, Wright
contributed a paper ‘On the Ammonites of the Lias Formation ’
(pp. 162-79, 235-45) describing various species illustrated in
four quarto plates, drawn by J. W. Salter. In his subsequent
Monograph he makes no reference to this prior work; and vet the
descriptions therein of the species concerned are almost word for
word identical—just a few alterations ike millimetres for inches,
changing one technical term for another, and occasionally a few
additional remarks; while the figures of the species are in very
many cases apparently not redrawn from the specimen, but merely
copies of the illustrations in the prior paper.

The search for information as to the localities of certain of
Wright’s specimens, in connexion with the discussion on the
Bredon fauna referred to above (p. 312), led to the discovery that
the Cotteswold Club paper was important for the understanding of
Wright’s Monograph, for the identification of some of his species,
and for the recognition of some of his figured specimens, several of
which do not seem to have been found. Therefore I append the
following notes, commencing with a list of the species figured in
the Cotteswold Club paper, marking those which are refigured
in the Monograph.

part 4] JURASSIC CHRONOLOGY : LIAS. 319

TABLE XX.-—COMPARISON OF FIGURES.

Species. Cotteswold Club paper. Monograph.
PI, fig. Plt fig.

TA PIGHOTDIS .2......0......--- tle LS doles
a Gin re 2, 2a. rie 1-3.
le nie Tr ay MRT BO;
Lote 2 Sa i, 3a. XXxii, ie
ids” Clo Piha ao a, 3b. XXxil, 8
PAMOMGUNGLUS 0.000. le af 4, 5.
PASO MCOONWS! 85.0. oon usa li, Wa iOsCe vill, 1-8.
LDtS Gh Twi aby viii, 5.
AM SCHEIGOSEQTUS: 2.0.0. 60... yes. ifs 2, 3.
Je MIT TO Die' | a li, A, Sale EOD
LL Eas oe i rr ll, 4a. xt, De
wuld. | Clo. Oe a Bla 4b. xil, 6.
Me WT, ll, 5 side. vi, 4A
[Ney oto | Se ie 5 front.
j30. 0. ti, CE vi,
ACU LES ii, a, Vis
10h LUO se ae irr lil, la.
PANCONMUUCOIT) ..2....4)......5-, ane Ae Be i, bias
TTL 0s 0 iil, 3 a. ll, 3.
Lh. UTS) Si ee a lv, ha wlb: Sordi tee
18), Ol: ea er bye IG: mex DLP
As mulincostatus ............ Iv, 2G, 210, 20.

(A. bisulcatus in text).

A. bucklandi.—Same figures in Mon. as C. C. paper, just under
half of the natural size. Whales: of whorl given by Wright in
text in both cases =33 per cent., but figure airs only 25:5.

A. birchii.—Mon. figs. appear to be tracings of C. C. figs. :
there is the same omission in both—failure to show inner row of
tubercles in front view. The suture-line is said to be from a
Bredon specimen. The point was whether figs. 5 & 6 represented |
a specimen from this locality, and if it was of the natural size
what it could be. I come to the conclusion that it is from Lyme
Regis and is a large shell reduced, on these grounds :—

In the C. C. paper, p. 179, Wright says, ‘The finest specimens
of this shell are found near Charmouth and Lyme Regis.’ On
p. 178 he gives the ‘transverse diameter of a large specimen
8 inches,’ and the proportions he gives work out as 203, 19,
21:5, —; he also mentions that the shell has 7 turns and 32 to 34
lateral cost. The C.C. example has 7 turns, has 33 spines on
outer row of last whorl, and the proportions of the figure are 84,
22, 18 (22), 61. I think that the figure represents the 8-inch
example reduced—the dimensions of aperture transposed by
Wright—and that when he transferred the figures to the Mon.
he called it, in error, a small shell. It will be interesting to see
where this leads.

In the Mon. Wright describes (p. 332) his large specimen as
160 mm. diam., and the proportions that he gives work out as
160, 22, 22,60. The figure, however, is 166, 22, 23, 58. He goes

320 MR. 8. 8. BUCKMAN ON [vol. lxxin,

on to describe, not this specimen, but his large example of 8 inches
in diameter as in the C. C. paper, though occasionally referring to
the figures of pl. xxiii—the 160 (166) mm. or 64-inch specimen.

In regard to the figs. in -pl. xxx he says ‘Small specimen
Pl. xxxu, figs. 5-8 [5, 6], Diameter 80 mm.,’ and so on—the
proportions which he gives work out as 80, 19, 19, 62, though
the fig. gives 83, 22, 18,61. It might be urged from this that
Wright must have measured from the actual specimen, and not
from the C.C. figs. But, in view of what comes out in other
cases, this fact of the measurement hardly carries the weight that
it might. Suppose, however, that this be aecepted—that this
specimen was a small one—it leads to curious difficulties. The
specimen certainly does not show what Wright figured it for in the
Monograph—‘ that 4igoceras Birchii maintained its original form
and structure through the various phases of its life’—Explanation
of pl. xxxui. For the shell shows that if small it could not possibly
be a young bzrchi. It has the proportions of an adult. To bea
young dzrchi 1t would have to show no more than 6 turns at this
diameter, only about 23 spines on the outer row of the outer whorl,
and proportions 83, 27, —, 53. Also it should show a smooth
stage up to half an inch in diameter, as Wright says in his C. C.
paper—his figure shows only a smooth stage up to about a fifth
of an inch in diameter, which would be correct for a shell reduced
to less than half.

If, however, this be not a young Jzrchi, but is still figured of
natural size, then it must be regarded as a development of birch
which has taken on the characters of adult birchi at a smaller
size—an instance of acceleration or tachygenesis. That it shows
so exactly the number of turns, the width of umbilicus, the
narrow whorl of an adult, that it has kept exactly the number of
tubercles—33—on outer row of last whorl, that it shows no change
in character of tubercles, no further differentiation between outer
and inner rows of tubercles, no sign of degeneration, and no change
except a degree of whorl-compression which might be found toa
ereat extent in a specimen of 203 mm. as compared with one of
160 mm., strains credulity too greatly. That a small shell, being
a morphic representative of an adult, and necessarily as a develop-
ment of it separated from that adult by a very great number of
generations, should yet be almost a photographic likeness of the
adult, is a degree of similarity in morphic representation which
seems far too exact.

I think, therefore, that Wright’s C. C. fig. of Ammonites birchii
which he reproduced in his Monograph as a small shell, is really
his large 8-inch example figured less than half natural size, that
it is only understandable on that basis, and that therefore it is
from Lyme Regis and not from Bredon. At any rate the 8-inch
bircht which Wright described in his C. C. paper ought to be
still in existence, and Curators would be well advised to look out
for it.

part 4| JURASSIC CHRONOLOGY: LIAS, 321

A. sauzeanus.—The large specimen is said to be of the natural
size—Explanation of pl. viii of Mon.; it is actually x0°7. It is
figured half of the natural size in C.C. Diameter there given as
8 inches, in Mon. as 205 mm.

The small shell is said to be of the natural size in Mon.
It is figured x 0°73 of this in C. C. paper.

A, turneri.—Shell figured of reduced size, x 0°7, in C. C., but
same side shows nearly all inner whorls as missing. Same pro-
poston given in C.C. & Mon. In C.C. fig. 4a is described as
“Quenstedt’s figure of the septa,’ Explan. of Plate. In Mon. fig. 5
is an exact copy but enlarged, apparently from Bredon specimen
(p. 292).

A. brooki.—‘ Dimensions.—Transverse diameter 53 inches
[140 mm.]; height of outer whorl at the aperture, 2%, inches
[56 mm.|]; width 14 inch [38 mm.]|.”’ C. C. p.174. In Mon.
140 mm. 55mm. 40mm. Shell figured 0°65 in C.C. ue and
front view given—a detail lackingin Mon. Fig. 5a@in C.C. ‘lobes
and saddles from Zieten’ (Explan. of Plate). Fie. 5 in: Mon., copy
of C.C., ‘foliations ... from another specimen ... My Collection.’

A. rotiformis.—Specimen figured in ©. C. paper, peripheral view
only, ‘3 nat. size’ inscribed on Plate. Diameter (p. 238), 7 inches;
therefore figure is x 0°74. Natural size in Mon.

On p. 279, Mon. the sentence ‘Compare, for example, the sutures
in Pl. i, fig. 2, with those in PI. iv, fig. 2” does not refer to Mon.,
but is understandable from C. C. paper.

A. conybeary.—tIn C.C. ‘4 nat. size’ inscribed on Pl. Figure
175, 19, 20, 64:5. Dimensions (p. 236): 107 inches, 2 inches,
2 inches=T. 260, 19°5, 19-5, —, figured therefore x 0°67. Same
figs. same size in Mon.; but Wright (p. 275) gives dimensions
340 mm. (183 inches), 60 mm., 68 mm., —, = T. 340, 17°5, 20, —.
Wright has ranehly doubled the diameter of the ©. ©. fig. instead
of giving the dimensions of his text. Loc. Weston, C. C. p. 236,
Salford, Mon. p. 273, Saltford, Expl. Pl. u.

A. obtusus.—Inscribed on C.C. pl. ‘3 nat: size,’ shows a con-
tracted umbilicus and inner whorls wanting or hidden in matrix.
Dimensions not given in C.C. Same figures, same size given in
Mon.. but with more open umbilicus showi ing inner w horls. ‘Nat.
size’ in Explanation of pl. xxi. Dimensions in Mon. (p. 293)
155 mm., 65 mm., 58 mm., 55 mm. This makes figs. x 0°70.
Figures in C.C. and Mon. do not agree one with the other, nor
with the text as regards proportions.

A, multicostatus.—In text C.C., p. 240, ‘A. bisulcatus.’ The
figure of C.C. not reproduced in Mon. In C.C. ‘ Dimensions.—
Transverse diameter 8 inches; height of aperture 2? inches; width
of aperture 24 inches.’ In Mon. p. 276 are the ae: dimensions
turned approximately into millimetres 200, 70, 64, but apphed to

Q. J. G.S. No. 292. 26

322 MR. 8S, 8S. BUCKMAN ON - svolsixectias

a specimen ‘ Pl. in, fig. 1,’ which figure shows 186, 51, 45 mm. in
these cases, comes from another locality, and has different ribbing.
The proportions of the C.C. shell are F. 148, 34, 32, 44, T. 203,
34°5, 31, —, and of the Mon. shell, F. 186, 28, 24, 49.

The whole of the article in Mon. is practically that of the C. C.
paper. On p. 276 is a reference (footnote) to Vol. iti of the
Proceedings of the Cotteswold Club. In the C.C. paper this
footnote cited a prior page of Wright’s own paper; in Mon. it cites
a page to which it has no reference—another paper, already cited
in footnote of previous page of Mon.

It will thus be seen that the C. C, paper gives much information
necessary to an interpretation of the Monograph; and that there
are several specimens figured in that paper which should have been
in the Wright collection, and have been lost sight of : Curators
should look out for them.

Now, however, comes another point of interest—Wright’s C. C.
paper and his plates of the year 1864 were known to Reynés in
Marseilles within a short time of publication.

The plates of Reynés’s Monograph contain (as we know) many
original figures, but also many copied from other works. Most of
these are easily recognizable, although there are no statements as to
source. All the text issued with the work is the small pamphlet
edited by Dr. P. de Ronville, introduction dated 1879. In this is
the first part of the text of the ‘ Monographie des Ammonites,’
dated 1867, presumably the year in which the Monograph would
have been issued, but for the Author’s premature death. The
preface to this part is dated by Reynes July 14th, 1866. The
unmediately following Biblhography extends to the year 1864, and
under 1863 is ‘Wright, On the Ammonites of the lias formations,
London.’

In his pl. xxxvu, figs. 3 & 4, as A. brooki, Reyneés has shghtly
reduced copies of Wright’s A. brooki, C. C. pl. u, fig. 5; and in
his pl. xlin, figs. 6 & 7, Reyneés has again as A. brook copies of
Wright’s A. turnert from Bredon, C.C. pl. u, fig. 2. On the
other hand, Arzetites scipionianus, Wright, pl. xin, published in
1879, and Reynés’s Ammonites scipionis, pl. xxvii, figs. 7-9, illus-
trate the same specimen; and, looking at the identity of details,
Wright’s plate is presumably a copy of Reynés’s plate in existence
10 years earlier, though not formally published until 1879.

It follows from the above remarks, about the specimens repro-
duced by Reynés from the C. C. paper, that the suggested possible
presence of the Barrow-Bredon Arietites fauna in the Rhone
Basin fails (p. 311), that the isolation of this fauna is thus more
remarkable, and that any argument for a chronological difference
of these Arietites and the Microderocerates of the ¢nflatwm set is
strengthened. It also follows that the difference of ribbing noted
for Reynés’s figure of A. brooki is merely due to reduction in size.

} However, his ‘ Essai Géol. Aveyron,’ bears date 1868,

part 4] JURASSIC CHRONOLOGY : LIAS. 323

Reduction when not accompanied by a note to that effect is most
misleading, as it makes ribs appear unduly approximate. Such
reduction may be misleading in other cases in Reynés’s figures.

I have not altered what was previously written about these
matters, but have appended references to this page.

It is greatly to be desired that some one with access to the
material in the Marseilles Museum should issue an explanatory
text of Reynés’s plates, indicating which are figures of original
specimens and their localities, which are copies and their sourees.
It would be a grand monument to one who must have possessed an
almost unique ‘knowledge of Ammonites, and a fitting accompani-
ment to a wonderful series of plates. It would help ‘to repair the
loss which science undoubtedly sustained in the premature death
of an author who gave promise of discriminative ability much in
advance of his time.

|Since this paper was read I have found that Neumayr made
much the same suggestion, in his review of the work (Neues

Jahrbuch f. Min. ete., 1880, vol. ii, Referate, p. 394). |

EXPLANATION OF PLATES XXVI-XXXI.

{ All figures are of the natural size, unless otherwise stated. All specimens
are in the Author’s collection, unless otherwise stated. |

PLatTE XXVI.
Figs. la—2b. LEPTALEOCERAS LEPIUM, Sp. nov., p. 285.

Fig. 1a. Side view; fig. 1b, apertural view. Holotype from Marlstone, South
Petherton (Somerset) { Domerian, pre-s -gibbosa|}; ex coll. D. S.
Darell. Figs. 2a & 2b. Same views of a young shell from
Middle Lias, Gretton, Winchcomb (Gloucestershire); pres. J. G.
Hamling.

Figs. 3a & 3b. Lerraceoceras aff, Leprvm, p. 285.

Fig. 3a. Side view; fig. 3b, apertural view. From Middle Lias, Gretton,
Winchcomb [| Domerian, pre-gibbosa| ; pres. J. G. Hamling.

Figs. 4a—4c. ACANTHOPLEUROCERAS RURSICOS1a, Nom. nov., p. 286.

Fig. 4a. Side view, body-chamber, X 0°5; fig. 46, whorl-section, x 0°66,
taken at the break : left side is somewhat erushed ; fig. 4c, view
of dorsum of end of last whorl, showing subsidiary costule of
penultimate whorl. Natural size. From Middle Lias clays,
Leckhampton (Gloucestershire) [ [ Hwiccian—Wessexian | ; pres. late
Rev. F. Smithe.

PLaTE XXVII.
Figs. la & 1b. RapsrocKICERAS COMPLICATUM, Sp. NOY., p. 287.

Fig. la. Side view, test and carina only on first half-whorl; fig. 1 b, peri-
pheral view, first half of outer whorl; both figs. x 0°5. Lower
Lias, (Radstock) Somerset; Deiran, Radstockiceras 1. See also
pp. 294-95, figs. 6, 12, 21.
2.62

324.

MR. §. 8S. BUCKMAN ON [ vol. lxxiu,,

Figs. 2 & 3. GsETICERAS GLETENSE, nom. nov., p. 289.

Fig. 2. Sectional view of holotype, x 0°5. See Pl. XXVIII, figs. 1 & 2, and

Fig.

p. 294, fig. 5. Fig. 3. Side view of a paratype, a young example,
x 2; ‘Middle Lias, raricostatum, lower part of Folly Lane Brick-
yard, Cheltenham (Gloucestershire); Deiran, Gleviceras y. See.
Pl. XXIX, fig. 3, and Pl. XXX, fig. 4, for other illustrations of
same example.

PuatEe XXVIII.

Figs. 1 & 2. GLErIcERAS GLEVENSE, nom. nov., p. 289.

. Side view of holotype, x 0:5; Middle Lias, ‘ raricostatwm hemera,’

lower part of Folly Lane Brickyard, Cheltenham (Gloucestershire) ;
Deiran, Glevicerasn. For sectional view see Pl. XXVII, fig. 2, and
see also fig. 5, p. 294. Fig. 2. Side view (part) of paratype taken
as genotype; Lower Lias Shales, Cheltenham, ex J. Buckman Coll.
(‘Am. greenhoughii’) [Deiran, leviceras n]. See also pp. 294-95,
hes Ae de, 2 :

Fig. 3. MrcroDEROCERAS INFLATUM, sp. noy., p. 305.

. Apertural view, X0°66. See Pl. XXIX, fig. 1.

Fig. 4. ARNIOCERAS FORTUNATUM, Sp. nov., p. 301.

. 4, Peripheral view, natural size. See Pl. XXXT, fig. 4.

PLATE XXIX.

Fig. 1. MrcropEROCERAS INFLATUM, Sp. nOV., p. 305.

. Side view, x 0°66; Lower Lias, Barrow Gurney (Somerset) [ Lymian—

Mercian, post-birchi|. See Pl. XXVIII, fig. 3.

Figs. 2a & 2b. ARIETITES TURGESCENS, Sp. nOov., p. 296. ©

2a. Side view ; fig. 2b, peripheral view showing loss of carina, with long.

ventral projection and sudden return to a rounded venter with a
much shortened rostrum; both figures x 0°5. Lower Lias, Barrow
Gurney. (Somerset) [ Mercian, post-twrneri]. See Pl. XXXTI, fie. 5.

Figs. 3. a—8c. GLEVICERAS GLEVENSE, nom. nov., p. 289.

ig. 3a. Side view ; fig. 3b, peripheral view ; both figs. x 1°25; fig. 3c, part

of side view showing suture-lines marked in on photograph, x 2.
See also Pl. XX VII, fig. 3, Pl. XXX, fig. 4, for other illustrations
of same specimen; also Pl. XX VII, fig. 2 & Pl. XXVIII, figs. 1-2. -

PLATE XXX.

Figs. la & 1b. MicroDEROCERAS DEPRESSUM, Nom. noy., p. 303.

r, la. Side view ; fig. 1 b, apertural view of holotype ; Lower Lias, Barrow

Gurney (Somerset) [Lymian—Mercian, circa birchi]; pres. J. W..
D. Marshall.

Figs. 2a & 26. MrcropERoCcERAS SEPTIGERUM, nom. noy., p. 304.

. 2a, Side view; fig. 2b, apertural view. ‘ Lower Lias Shales, Cheltenham

[ District |,’ Gloucestershire, {Bredon, Worcestershire], { Lymian—
Mercian, post-birchi]; ex J. Buckman Coll. (‘ Ammonites birchii’)..

Quart. Journ. Geox. Soc. Vor. LXXIII, Pu. XXVI.

Ab. x 0-66

J. W. Tatcher, Photo. Bemrose, Collo., Derby.

LEPTALEOCERAS, ACANTHOPLEUROCERAS.

Quart. Journ. Geot. Soc. Vor. LXIII, Pu. XXVII.

J. W. Tutcher, Photo. Bemrose, Colla, Derby.

RADSTOCKICERAS, GLEVICERAS.

| Quart. Journ. Geor. Soc. Vor. LXXiIl, Pi. XXViIl.

J. W. Tutcher, Photo. Bemrose, Collo, Derby.

GLEVICERAS, MICRODEROCERAS, ARIETITES.

Quart. Journ. Geox. Soc. VoL. LXXIll, Pr. XXIX. |

J. W. Tutcher, Photo. Bemrone, Colla, Derby.

MICRODEROCERAS, ARIETITES, GLEVICERAS.

Quart. Journ. Geo. Soc. Vor. LXXIII, Pr. XXX.

J. W. Tutcher, Photo. Bemrose, Colo, Derby.

MICRODEROCERAS, GLEVICERAS.

Quart. Journ. Geo. Soc. Vor. LXXIII, Pt. XXXI.

J. W. Tutcher, Photo. Bemrose, Collo., Derby.

GLEVICERAS, ARNIOCERAS, ARIETITES.

‘part 4] JURASSIC CHRONOLOGY: LIAS. 325

Figs. 3a-3d. GLericeras RIPARIUM (Oppel), p. 292.

Fig. 3a. Side view, last half of whorl somewhat crushed ; fig. 3 b, peripheral
view of first half of whorl; fig. 3c, peripheral view with ribs,
auriculoids, and their connecting pseudo-carina marked diagram-
matically ; fig. 3d, part of side view with auriculoid marked dia-
grammatically, also suture-line (approximate): the incipiently-
trilobulate superior lateral lobe is on the edge of the periphery in
line with auriculoids. All figures X 2. Lower Lias ‘orynotwm,
Aston Cross, Tewkesbury (Gloucestershire) [ Deiran, biferum ].

Fig. 4. GLEVICERAS GLEVENSE, nom. nov., p. 289.

Fig. 4. Radial line and rib-scheme of example figured in Pl. XXVII, fig. 3, and
Pl. XXIX, figs. 3 a—3c, marked diagrammatically in photograph,
x2. See also Pl. XXVII, fig. 2 & Pl. XXVIII, figs. - 1-2, for
illustrations of other examples.

Figs. 5a &5b. GLericErRAS AURITULUM/GLEFENSE, p. 291.

Fig. 5a. Suture-line of specimen figured in Pl. XXXI, figs. la & 1b, marked
in diagrammatically on the photograph; fig. 5b, rib-scheme with
auriculoids similarly marked in; both figures x 2.

PuaTE XXXI.
[A white x marks the beginning of the body-chamber. |

Figs. la & 1b. Grericeras AURITULUM/GLEVENSE, p. 291.

Fig. la. Side view; fig. 1b, peripheral view ; both figures x 2. From Lias,
Charmouth (Dorset) [Bed 92]; Coll. James Francis. {[ Deiran,
Gleviceras n.| See Pl. XXX, figs.5a & 5b.

Figs. 2a & 2b. ARNIOCERAS FLAVUM, nom. nov., p. 298.

Fig. 2a. Side view; fig. 2b, peripheral view; holotype; Lias Limestones,
Lyme Regis (Dorset) | Lymian, Arnioceras 7 }.

Figs. 3a—3d. ARNIOCERAS ANAGENETICUM, Sp. nov., p. 300.

Fig. 3a. Side view; fig. 3b, apertural view; fig. 3c, periphera] view, taken
at the end of the whorl, showing ribs, nodes, keel, and incipient
sulei—all these figures are of the natural size; fig. 3d, part of
whorl, showing suture-lines, X 2. Lias Limestones, Lyme Regis
(Dorset) [Lymian, Arnioceras 1 |.

Figs. 4a & 4b. ARNIOCERAS VORTUNATUM, Sp. nov., p. 301.

Fig. 4a. Side view, natural'size; fig. 4b. suture-lines, approximate delineation
of last one, not clearly shown, taken at x. Lias, Paulton, near
Radstock (Somerset) [Lymian, Arnioceras n]. See Pl. XXVIII,
fig. 4.

Fig. 5. ARIETITES TURGESCENS, sp. nov., p. 296.

Fig. 5. Part of periphery, with rib-curves marked diagrammatically, showing
change after loss of keel. See Pl. XXIX, figs. 2a & 2b.

DISCUSSION.

\

Mr. W. D. Lane said that, while heartily welcoming the paper,
he would wish to criticize it from two points of view.
(1) In applying the principle of faunal dissimilarity, the

320 JURASSIC CHRONOLOGY: LIAS. [ vol. lexi,

Author appeared to disregard the alternative possibility: namely,
that, in certain cases, ammonites may have had very restricted
horizontal ranges. It is not enough to point to ammonites as being
strongly-swumming organisms. So are fishes: yet many marine
fishes are strictly limited in their horizontal distribution. The
details of the temperature and currents along the Liassic shore-line

were not known sutticiently for us to decide how far the ammonites

of any one locality would be restricted; nor did our knowledge of
their bionomics enable us to say whether these or other factors
might have limited their distribution.

It is extremely improbable that the Oxycones in the Oxynotus-
Bed of the Dorset Coast are derived, since, with the pyritized speci-
mens are found others, manifestly un-derived. consisting as they do
of films on the clay.

(2) Concerning the nomenclature of stages and of zones, two
opposing principles are followed by different. authors. According
to the one, the name of a stage or zone is taken, and its boundaries
altered, if desired. According to the other, the original con-
notation of the term is retained, and, if new divisions ‘are
needed, the original stages are subdivided. Thus, Bonarelli sub-
divided the Charmouthian into Domerian and a lower, unnamed
division, which was subsequently termed ‘Carixian’; but the Author
had meanwhile restricted the term ‘Charmouthian’ to this lower
division, which he now subdivides. Nor was this all, for most of
his Raasayan is part of the Sinemurian. Therefore, it would be
necessary to say Charmouthian of Mayer-Eymar, Charmouthian of
Buckman, and so on. Similariy, Wright instituted a zone of
A. turneri, but this is by no means the zone of A. turneri of the
paper now under discussion ; and instances might be multiplied.

It would be advantageous if an agreement were to be arrived at
among geologists as to which principle should be adopted. The
speaker strongly advocated the latter principle, and added that its
application should not reach back to old and well-established terms.

Dr. A. M. Davres said that, for nearly thirty years, the Author
had been developing ideas on the Jurassic Period in a series of
papers in the Society’s Journal. Starting with the Inferior Oolite,
in which non-sequences could be demonstrated by stratigraphical
as well as paleeontological evidence, he was now extending this prin-
ciple in the investigation of strata where only the latter was usually
available. While the conditions of deposition of the West Euro-
pean Jurassic were such as to favour’ local alternations of erosion
and deposition, it was possible that some inconsistencies of faunal
sequence might be explained in another way—by alternate contrac-
tion and expansion of the geographical range of a genus. Even if
the Author’s explanation should not be confirmed in every case, the
Society ought to be grateful to him for bringing so many new facts
and suggestions before them; and also, incidentally, for having
induced Mr. Tutcher to present them with some of the results of
his long and careful work in the Bristol area.

ree

part 4:| JURASSIC CHRONOLOGY : LIAS. 327

Mr. G. W. Lamprvau said that, while recognizing the scientific
value of this intensive study of the Liassic ammonites, he feared
that the Author’s continued refinements of the nomenclature and
zonal classification had carried the subject beyond the reach of the
ordinary field-geologist. From the imperfect nature of the evi-
dence, such exactitudes as those shown in the tables could rarely
be applicable in the field. The use of fossils by the stratigrapher
in the past, though crude, had generally been effective for his
purpose; but he could not be expec cted to master the complicated
technicalities of these new methods. The stratigraphical deduc-
tions drawn solely from these palwontological studies did not
inspire confidence.

Dr. J. W. Evans thought that the questions raised by the paper
were of considerable importance, with reference to the problem of
determining the time occupied in the deposition of sediments. If
the numerous non-sequences believed by the Author to exist were
substantiated, there could be little doubt that there must be many
more of shorter duration for which no paleontological evidence
was available, and the conclusion would be justified that the
geological record was of a far more fragmentary character than
generally believed, and represented only a small fraction of the
time that actually elapsed. In this way would be explained the
contrast between the hundreds of millions of years for the age of
the Paleozoic formations postulated by workers in the field of
radioactivity, and the tens of millions arrived at by those who
based their conclusions on the rate of deposition (see Proc. Geol.
Assoc. vol. xxiv, 1918, pp. 243-44).

328 MR. T. H. BURTON ON THE MICROSCOPIC _[ vol. Ixxiii,

10. The Microscopic Matertat of the BuntTER PEBBLE-BEDS
of NoTTINGHAMSHIRE, and its PROBABLE SOURCE of ORTGIN.
By Tuomas Harris Burron, F.G.S. (Read May 2nd,

1917.)

CONTENTS. Page
3 a roduetion | 2).25.23.32.8. a la 328
II. Physical Characteristics of the Sand .................0..0..020- 328

III. Description of some of the Simple Minerals .................. 329

TY. Conclusions as to the probable Direction of the Sediment-
bearing Currents, and as to the Sources of the Mineral
GYAMS 2.5. Vee is iscsi cs vst sdeasss sis eae eee 331

I. INTRODUCTION.

Sampres of sand were carefully collected from all the principal
exposures on the outcrop of the Pebble-Beds in Nottinghamshire.
It was cleaned in hydrochloric acid, sifted, and then separated by
means of Thoulet’s Soiution having a specific gravity of 2°77.
Enough of each sample (namely, 2 ounces) was taken to give
a heavy residue sufficient to weigh and to mount as permanent
objects for the microscope.

II. Puystcan CHARACTERISTICS OF THE SAND.

The sand in the exposures is more or less coherent, in many cases
taking on the appearance of hard rock. It may, however, when
dislodged (the cement being mainly ferric oxide) be easily crumbled,
often between the fingers.

At depths of 102, 211, and 307 feet, cores at the Farnsfield
borehole, near the Midiand Railway Station, showed the rock to
be compact, hard, and very caleareous Microscopic examination
proved this to be the only real difference when compared with
samples taken from the exposures.

The sand varies in texture and colour, coarse-grained material
largely predominating; but the following distinct types may be
recognized :-—

1. A coarse sand, whitish yellow to buff and brown in colour, found
in most exposures.

2. A reddish sand of medium coarseness, found in all the principal
exposures.

3. A dark brownish-red sand of fine texture, used for moulding purposes,

found especially at Whisker Hill Quarry near Retford. and at
Bestwood Warren.!

Samples? were all taken from No. ‘2.’ Ordinary bedding may

1 <The Geology of the Country between Newark & Nottingham’ Mem. Geol.
Surv. 1908, p. 34.

2 See map (p. 332) for localities from which sand was collected for
separation.

EE —— a

part 4]. MATERIAL OF ‘BUNTER PEBBLE-BEDS. 329

be observed, but false bedding is a marked characteristic of this
formation.
The following simple minerals, aggregates, and compound grains
have been found :—
SIMPLE MINERALS.

MGarneb ............ x Xx Pyrrhotite ...... AO | Muscovite.
Bigorspar......... SK | ANECOR. H'cps. SOX OS. |.4 Oreboekise.
Magnetite ...... << he, Bettas: Meee *% X | Plagioclase.
‘Quartz. | PAMAGASE Fb. x Microcline.
Vourmane .-.... XxX | Staurolite ..:... x x X Kyanite...... x
Apatite. ......... x | Sillimanite ...:.. x
Timenite ......... Bee fd LOGIE once Je x

Be occurrence.

Heavy minerals marked thus:— , xx _ frequency.

x X & abundance.

Mineral aggregates and compound grains include :—
Shimmer-ageregates, . chloritic aggregates — probably ; felsite,
eryptoperthite, quartzite, leucoxene, quartz—in addition to decom-
posed iron-ore, vein-quartz, chert, and schist.

Per cent.
QUERGA SAM ee A, 72
Estimated general constitution } Felspar ............... 25
of Pebble-Bed sand............ Heavy minerals ...... 0°25
VaOusts Somes Eats 2°75

II]. DESCRIPTION OF SOME OF THE SIMPLE MINERALS.

Garnets, mostly of a characteristic pink, appear to be fairly
evenly distributed, though they are not very plentiful. Spherical,
irregularly-rounded, and angular grains are present, the last-men-
tioned being the least frequent. Most of the garnets are isotropic,
while a few have been observed to be optically anomalous. ‘The
largest grain noted was 0-40 mm. in greatest diameter. Generally
they are smaller, some considerably so.

Fluorspar is fairly common. The grains are usually angular,
isotropic, and colourless. No grains having a greater length than
0-30 mm. have been noted.

Magnetic minerals! are fairly frequent, and include mag-
netite. Other magnetic grains of a yellowish-bronze colour are
probably pyrrhotite.

Quartz.—In form these grains are subangular, angular, and
well-rounded: the first constitutes the bulk of the quartz. The
biggest grains, comparatively few in number, are often apparently
perfect spheres. The grains are frequently more or less corroded.
Growths of secondary silica on the grains have not been met with.
Undulose extinction and other evidences of strain are frequent.

! These minerals were removed with an ordinary magnet from samples of
uncleaned sand.

/

330 MR. T. H. BURTON ON THE MICROSCOPIC (vol. lxxil,

The grains are often flattened and smooth. The average maximum
diameter of the majority of quartz-grains is about 0°51 mm.

Inclusions are :—(1) Regular; as tourmaline, rutile, apatite, sillimanite,
biotite.
(2) Irregular ; as gas and fluidal cavities, glass.
(8) Acicular ; as tourmaline needles, hair-like inclusions,
and fine needles—probably rutile.

Tourmaline, especially the brown kind, occurs abundantly,
mainly in the form of more or less rounded grains (a few appear
pertectly spherical), and in well-worn, mostly stout prisms. Nearly
colourless, blue, green, and mauve grains are present. The blue grains
are often very worn and rounded. The average diameter of rounded
grains is about 0-24 mm. Frequent inclusions of an opaque
mineral without crystal outline occur. Less frequent are fluid,
glass, and occasionally rods and needles, resembling sillimanite.

Ilmenite and leucoxene.—The former mineral is plentiful;
while the latter is very abundant, and rae be derived either from
ilmenite or from titaniferous magnetite.| Some ore of iron, in
most cases decomposed and resembling leucoxene, is attached: to
quartz, and is quite common. Iron- sand 2 is the most plentiful
form in which ilmenite is present.

Micaceous ilmenite occurs sparingly. Its colour is light
reddish-brown. The plates enclose rutile-needles, which are inter-
laced in the form of sagenite at an angle of 60°.

Zirecon.—This mineral is abundant, generally colourless, and
occurs, mostly in well-defined, though more or less worn crystals.
Almost spherical grains are not infrequent ; a small proportion is.
unworn. ‘The leneth ranges from about 0-07 nm. up to 0:30 mm.
Some pale-yellow grains resembling monazite, which I take to be
zircon, are not uncommon. Inclusions are frequent, consisting of
negative crystals, gas-enclosures, and what appears to be apatite.

Rutile is fairly plentiful, and occurs mostly in rounded grains
and rather stout, worn prisms. A few grains are fragmentary, but
show definite signs of wear. The colour varies from yellow to deep
amber-red. Both geniculate and polysynthetic twins are present.

Anatase oceurs sparingly. It is found in well-formed plates.
parallel to (O01), also attached to decomposed ilmenite. It varies
from colourless to pale yellow. The plates are not worn. The
smallest size noted is 0°05 mm., the largest size 0°10 mm.

Staurolite® is very abundant. One might almost call 1G, sue

id. J. HY Peall, © British’ Petrography~ VS8s,p. 167:

2 M. F. Heddle, ‘ Mineralogy of Scotland’ vol. ii (1901) Supplem. p. 197.

% Excellent figures of some Triassic heavy minerals may be found in
Dr. H. H. Thomas’s papers, Q. J. G. 8S. vol. lviii (1902) pls. xxxi—xxxii and
abid. vol. Ixv (1909) pl. xii.

part 4] MATERIAL OF BUNTER PEBBLE-BEDS._ B81

zone-imineral of this formation. The grains are often rough and
angular with frayed and toothed edges, averaging about 0°35 mm..
in greatest diameter. Nearly spherical grains occur. Its colour
varies from pale yellow, through amber, to reddish - brown.
Numerous grains are quite fresh, though some in a more or less.
decomposed . state are present. Among frequent inclusions are
opaque black particles, also quartz. Some grains appear to be pure.

The micas.—White mica is plentiful in most places, especially
in the eastern outcrop. The flakes are mostly parallel to (001),
and exhibit usually a low grey interference-colour between crossed.
nicols. Strain-shadows are frequent. The average diameter 1s.
about 0-53 mm.

A pale-green variety is not uncommon which, in contradistinetion
to the above white mica, mostly remains dark between crossed
nicols.

Biotite, so far as I can determine, is rare.

Felspar is usually found in a very decomposed and clouded
state. Orthoclase, which is probably plentitul, may be recognized:
strain-shadows are frequent. Only one or two grains of plag eee
have been definitely distinguished. Microcline is not uncommon.

CONCLUSIONS AS TO THE PROBABLE DIRECTION OF THE
SEDIMENT-BEARING CURRENTS, AND AS TO THE SOURCES
OF THE MINERAL GRAINS.

From the distribution of the aforementioned heavy minerals,
together with such evidence as the dip of the false bedding and the
an in thickness of the Pebble-Beds. the direction ae the chief
sediment-bearing currents may be deduced.

From the kind of mineral and the character of certain pebbles, we
can reasonably infer the source of origin of much of the material.

The accompanying map and table (p. 332) will help to
demonstrate the distribution of the heavy minerals.

Along the western outcrop the highest percentage of heavy
Sinai with a specific gravity of 2°77 and upwards, 1 is at Gorse-
thorpe. From Gorsethorpe a diminution in the percentage is
continued northwards, by way of Carburton, to Bawtry. South of
Gorsethorpe the fall in the percentage of heavy minerals is continued,
by way of Python Hill, to Nottingham.

Along the eastern outcrop we find the highest percentage at
Ollerton and Farnsfield. North of Ollerton to Retford there is
a considerable decrease ; while from Farnsfield to Calverton, in the
south, there is a marked diminution in the percentage of heavy
“nec

The current-bedding.—At Retford and Ollerton! the pre-
vailing dip of the eross-bedding is in an easterly direction. On

1 «The Geology of the Country around Olle1ton’ Mem. Geol. Surv. 1911,
p. 28.

o Fe
, xSP =
| Map of a
| Nottinghamshire &y Cx!
showing Bea ak
the Pebble-Beds dotted? /4---Bawtry..
Seale of Miles ee fe Ren reer
Z 4 6 Bay) Snes
fee =
Minor Current _ x o =
Ae
| = ithe
&) ES:
ae = "Uy Carbiniton-: 2:
4S Se SS) Pen e soanes
Su
4, Main Current Tpticstion- ere Hel
of Overiior x cits Co
omy
~
i N
13s
| al
2
ae
aor
ie
a A
|
ss ces

[The white circles indicate the localities from which sand has been obtained
for separation purposes. The crosses indicate the position of the bore-
holes where the thickest proved parts of the Pebble-Beds oceur. |

TABLE SHOWING THE LOCALITIES, THE WEIGHT IN GRAMS, AND THE

PERCENTAGE OF THE HEAVY MINERALS.

| Locality. | Weight. ithe Locality. | Weight. | Bie

'Bawtry .........| 1886 | 0244 || Retford......... 0602 | 0-106

| Carburton...... 1438 | 0-253 || Ollerton ........ | 1560 | 0-275

| Gorsethorpe ...| °3541 | 0°624 || Rufford......... | 0765 | 0-134
Python Hill ...; °1536 | 0-270 | Farnsfield ...... "1530 0°269

| Nottingham .../ +1380 | 0-243 || Calverton ...... 0296 | 0-052

A

ae

part 4] MICROSCOPIC MATERIAL OF BUNTER PEBBLE-BEDS. 333:

the Manstield—Southwell branch of the Midland Railway, between
Mansfield and Python Hill, 3 or 4 miles of excellent sections show
marked cross-bedding dipping south-eastwards.!

In the district about Nottingham the dip of the false bedding
shows a general direction towards the south-east.2

There are subordinate currents which come from the south-west
and south-east respectively, as, for example, in the Farnsfield
district.®

The general direction of the current-bedding is towards the east
in the northern part of the county, and veers towards the south-
east from the Gorsethorpe district, where the main easterly current
bifureates, as we proceed in the direction of Nottingham.

The thickest part of the formation, as shown by bore-
holes.—Kast of the Pennines, as proved by boreholes and shaft-
sinkings,* the Nottinghamshire Pebble-Beds are thickest at Bever-
eotes and Kelham, being 568 feet thick at the former, and 471
feet thick at the latter place.®

This thickest part is, in the main, in the line of the prevailing
currents, indicated by the distribution of the heav y minerals and
the general dip of the false bedding (see map and table, p. 332).

‘North of Bevercotes the Bunter Pebble-Bed assumes all the
characters of the Lower Mottled Sandstone’; ® while south of
Thurgarton’ the entire Bunter, as proved, is ‘thinner than the
Pebble-Beds in the localities named above.

The mineral grains and the possible sources of their
supply.—The outstanding mineralogical fact is the abundance of
staurolite. For this there is no adequate source of supply locally.
Ragged patches occur at Sinen Gill—in the Skiddaw Granite
series.8

I have not been able to discover it in the South Pennines, where
I have searched for it in the Cromford neighbourhood of Derby-
shire. It appears, however, to be abundant in Scotland, being
found in several localities,® from Unst in the north-east, roughly in
a south-westerly direction to Mull.

1 «The Geology of the Country around Ollerton’ Mem. Geol. Sury. 1911,
p. 22.
2 ‘The Geology of the Country between Newark & Nottingham’ Ibid. 1908,

p. 3. 3’ Ibid. 1911, p. 22.

4 These thicknesses are approximate; but they are the nearest procurable
approximations, and, when used for purposes of comparison with known facts
in the district in question, are certainly of much interest and importance, if
not of exact and accurate evidence in themselves.

5 *The Geology of the Country around Ollerton’ Mem. Geol. Sury. 1911,

p. 18.
6 W. Gibson, ‘ The Concealed Coaltield of Yorkshire & Nottinghamshire’
1913, p. 31. i Tind. p. 38.

8 ¥. H. Hatch & R. H. Rastall, ‘ Petrology’ vol. ii (1913) p. 248.

9 M. F. Heddle, ‘ Mineralogy of Scotland’ vol. ii (1901) p. 75 & ibid. Supple-
ment, p. 209; G. Barrow, Q. J. G. S. vol. xlix (1893) p. 340 & ibid. pp. 349,
350 ; T..O. Bosworth, Q. J.G.S. vol. Ixvi (1910) p. 394.

AND FROM THE UPPER eee. | |

_Occurrence represented by x. Frequency represented by XT 1

ROC eee Staurolite. Ilmenite. Zircon. Tourmaline. Rutile.

|
3
|

|
1, Wottimghani-|) WxX>oxK Xs oxox xxx xe | x Xx
-shire- | é
| Grains |
very fresh,
usually, |
| {
2, Cannock xX X X | XxX x X X iE | x X
Chase. ; |
Grains |
often | |
| more or less | |
decomposed. /
3. Cheshire <2... xX X | xXx | x XX | PO Se x X
| Much | |
decomposition | | 1
of grains. '
|
| | | |
|-4,Gromford | 2... aie | Sec aa xX igee.
se ae | | Zireon = Much fewer, Generally |
| | Jarger than | nearly round much larger q
inthe above grains than and more |
localities, | in the above | fragmental
localities. | than in jf
the above |
| localities. |

Much the most extensive development in Scotland appears to be
that described in the South-East Highlands by Mr. G. Barrow.

It thus seems evident that northern areas were capable of
supplying the staurolite.

Shimmer-aggregates,! sillimanite, kyanite, ilmenite, and micro-
‘cline, obviously from metamorphic areas, are most likely, in the

main, from the same sources.
‘In the Highlands, tourmaline is common and widespread.’ ?

G. Barrow, Q.J.G.S. vol. xlix (1893) p. 340 & pl. xvi, fig. 5
TO Bosworth, ibid. vol. xvi (1910) pp. 394, 395,

1
24

Aggregates.

hoax

Leucozene. Fluorspar. |

TER PEBBLE-BEDS OF NOTTINGHAMSHIRE, CANNOCK CHASE, AND CHESHIRE,
% CROMFORD IN DERBYSHIRE.

idance represented by X X X. Great abundance represented by X X X X.]

|
Muscovite. |

Remarks on
lighter material.

eh. xX
Me | XX
i ae

i)
| xxxx x

x xX X

| or less flattened.

xX X X

Generally rougher
than in the
above localities;
also yellowish,
rather than
colourless.

The majority of the
quartz-grains are
well worn and
smoothed; more

Do.

The majority of the
quartz-grains are
irregular, with
rough surfaces.

Microcline is plen-
tiful among the
lighter material.

Dr. Bosworth has informed me that it is found in the bulk of the
old Highland rocks. As it is practically certain, as shown by the
distribution of the heavy minerals (see p. 832), that the tourmaline
has not been mainly derived from southern sources, it is to

‘Scottish areas! that we must look for the supply, in larger part,
of this mineral.

Tourmaline, as well as rutile, garnet, fluorspar, and zircon, are
probably derived, in part, from local sources.
ferous rocks occurring in the Pebble-Beds (about 4 or 5 per cent.)

As the Carboni-

1 M. F, Heddle, ‘ Mineralogy of Scotland’ vol. ii (1901) p. 73; see also
‘The Geological Structure of the N.W, Highlands of Scotland’ Mem. Geol.
Surv. 1907, p. 285.

336 MR. T. H. BURTON ON THE MICROSCOPIC | vol. xxii,

namely : sandstone, limestone, and chert, have probably been derived
from the Pennine ridge, it is reasonable to infer that a small pro-
portion of the heavy minerals are also from the same source.
Subordinate currents! have also evidently contributed their quota
to help to form the Pebble-Beds.

It appears, therefore, that Scotland has furnished the bulk of
the staurolite, and of the other heavy minerals associated with it.
Tourmaline too, at any rate in greater part, is from northern
sources.

How, then, did the foregoing minerals reach Nottinghamshire ?
To answer this question, it is necessary to compare the material of
certain other localities with that under consideration.

The heavy minerals of Cannock Chase, Nottinghamshire, and
Cheshire Pebble-Bed sand that I have examined, are substantially
identical. They exhibit, on the whole, a marked difference from
those of the South Pennine district (see Synopsis, pp. 334-35).

Slices of quartz-felspar grits from the Pebble-Beds of Nottingham-
shire and Cannock Chase, also from Loch Torridon, show a striking
resemblance one to the other, both macroscopically and microsco-
pically. They are mainly composed of quartz and felspar, with an
addition of quartzite, pegmatite, and microcline.2. The similarity of
the Nottinghamshire material to that of Cannock Chase suggests
a common source of supply.

To the more numerous and distinctive rocks of the Pebble-Beds
of the Midland Bunter, Prof. Bonney ascribes a northern de-
rivation?: a north-western river and its tributaries being the
means of transport. This north-western river has probably played
an important part in the formation of the Nottinghamshire Pebble-
Beds. At certain flood-periods, when the supposed river was much
fuller than usual, and its outlet and the approaches thereto were
probably more or less obstructed by material brought down
previously, an overflow occurred. This was probably in the
neighbourhood of Macclesfield. The flood-water, with its load
of ‘sediment, forced its way across the high land of Derbyshire
into Nottinghamshire and the lower-lying lands of the east.5

The eae current of the overflow postulated above, ‘when it
reached Nottinghamshire, bifurcated in the Gorsethorpe district,
one branch flowing mainly eastwards by way of the Ollerton
district, and the other south-eastwards by way of Farnsfield.

1 <The Geology of the Country around Ollerton’ Mem. Geol. Sury. 1911,
p. 22.

4 «The Geological Structure of the N.W. Highlands of Scotland’ Mem.
Geol. Surv. 1907, p. 285.

3 Q. J. G.S. vol. lvi (1900) p. 302.

+ The staurolite of Nottinghamshire is fresher than the staurolite of Can-
nock Chase and that of Cheshire: this lends support to,the above-postulated
theory of obstruction. The material in the first instance (long accumulated
and weathered) was brought down by the flood-water into the western basin,
naturally more or less blocked later, and certain fresher material was similarly
brought from the north—much of the latter being carried by the overflow
into Nottinghamshire and the eastern lowlands.

5 A. J. Jukes-Browne,.‘ Building of the British Isles’ 3rd ed. (1911) p. 235.

—_.7, =

4
.
‘
:

part 4] MATERIAL OF BUNTER PEBBLE-BEDS. 337
|

From the foregoing statements it is evident that the bulk of the
material in question was most likely derived frora Scottish sources ;
that the Pennine ridge has certainly supplied a share; and that
subordinate currents have probably contributed their small part
towards forming the Nottinghamshire Pebble-Beds.

I gratefully acknowledge the obligations that I owe to many
for their kind assistance in connexion with this paper, especially
to the Rev. Prof. T. G. Bonney, Prof. H. H. Swinnerton, and
Dee He Thomas.

DISCUSSION.

Dr. R. L. SHernock thought that it was not clear what was
meant by the ‘Northern Bunter basin.’ This might be either west
or east of the Pennines. In either case it would be necessary for
the north-western river to cross the Pennine ridge, admittedly in
existence. Only in times of flood did the river bring sediment
through the hills into Nottinghamshire, and yet the bulk of the
material was believed by the Author to come from Scotland. The
speaker thought that a more local origin for the bulk of the
material was probable, and that, until the Carboniterous rocks of the
Pennines, and particularly the Millstone Grit, had been searched,
it was unsafe to assume that the heavy minerals could not have
been obtained locally. One objection to the theory that the bulk
of the Bunter material was brought from Scotland had never been
answered—it was, that the number of pebbles fell off as the supposed
source was approached. The speaker believed that the paper by
the late J. Lomas on the Origin of the British Trias explained
satisfactorily most of the features of Triassic rocks. On this
hypothesis, supported by the work done by the Egyptian Survey,
Dr. Wade, and others. the Bunter Pebble-Beds were formed by
torrential waters that occasionally swept out wadis, filled with
débris produced by desert erosion, and spread the materials over
a coastal plain at the foot of the hills. The rock-fragments
were not only rounded by mutual battering, but much fine silt
was produced which, when dry, was blown into pools and into the
Caspian-like sea to form Triassic marls. The chief difficulty was
the presence of quartzite-pebbles, but it was possible that these
might not have travelled far: say, from the buried pre-Triassic
rocks of Charnwood Forest. The quantity of pebbles in the
Pebble-Beds of Nottinghamshire was apt to be exaggerated, because
they were concentrated in soils and Drift, although in a clean
section there were usually quite few stones. Moreover, only a
moiety of these were quartzite.

It appeared from a lantern-slide that the Author had not
discriminated between the divisions of the Bunter. There are beds
in the Lower Mottled Sandstone which have a structure different
from that of the Pebble-Beds, and the former were laid down in
very shallow water. The sands at Whisker Hill, Retford, one of

Q. J. G.S. No. 292. 20

338 MICROSCOPIC MATERIAL OF [vol. lxxin,

the localities collected from, could be described as Upper Mottled
Sandstone.

The speaker was interested to find that a belt, containing a high
proportion of heavy minerals, extended across the strike of the
Bunter opposite Gorsethorpe. This was confirmation of his ex-
planation given some years ago of the origin of the Mansfield
Sandstone in the so-called ‘Permian’ below. The explanation
required a river flowing in from the Pennines, in practically the
position described by the Author.

The Author was to be congratulated on the work that he had
done. It had been customary for geologists to collect Bunter
pebbles, and ignore the sands in which they lay. Dr. Thomas had
done pioneering work in Devon on these sands, and the Author had
now accomplished useful work in another area.

Dr. P. G. H. BoswEetn remarked that a paper dealing with the
petrography of the Bunter deposits was certain to be of consider-
able interest, and the Author’s contribution was clearly no
exception to the rule. While the records of detrital mineral
assemblages were very valuable, it was obvious that great caution
should be exercised in drawing inferences regarding the source
of the material. A great deal rested on the number of samples
collected, their selection, and their vertical and lateral distribution.
With regard to this, he (the speaker) wished to utter two words of
warning, which might, however, be unnecessary in the case of the
paper under discussion.

The variation in the percentage weight of the heavy mineral
residue did not necessarily give any indication of the source of the
material. It was now an established fact that the heavy crop
increased with the decrease in grade-size in sands, and the orade
or mixture of grades in every sample must therefore be determined.

In the next place, the presence of minerals of metamorphic
origin, such as tourmaline, staurolite, garnets, micas, ete., in sedi-
ments did not necessarily indicate origin from metamorphic rocks.
Such minerals were frequently the least unstable, and were found
in most sedimentary rocks in the British area: some of them
might have passed through several geological cycles, and have been
derived directly from older sediments.

Mr. Beryarp Smirn was of opinion that the chief value of
the Author’s work consisted in his careful and useful determination
of the mineral residues, but that much more work of a similar
nature must be undertaken before such broad conclusions could be
drawn with safety. He emphasized the fact, which he himself had
been the first to put on record, that at Farnsfield the direction of
dip of the cross-bedding was roughly from south to north, swinging
now to the west and now to the east. While agreeing in general
with the objections raised by Dr. Sherlock, the speaker was not
prepared to follow him’ in suggesting that the Pebble-Beds were
accumulated by river-action on an exposed coastal shelf, but con-
sidered that they were deposited in shallow water. The pebbles
appear to have entered the district from the south, but probably

part 4] BUNTER PEBBLE-BEDS. 339

most of the finer material was derived from the Millstone Grit or
Coal-Measure sandstones of the neighbouring Pennine Range, the
existence of which is indicated by the occurrence—between Dale in
Derbyshire and Lenton near Nottingham—of Bunter sandstone
banked against cliffs of Coal-Measure sandstone that were sub-
jected to atmospheric weathering at that time. An examination of
the heavy minerals of these rocks should throw considerable light
upon the origin of the Bunter.

Mr. W. H. Boorn stated that a boring made at Farnsfield, some
twenty-two years ago, entered the Waterstones, and the water-level
was within a few feet of the surface, the rocks being therefore
fully submerged. A little later, a deep borehole was put down at
Newark-on-Trent at Messrs. Hole & Company’s brewery. It was
taken to about 800 feet by the Diamond Boring Company, and the
water rose to 50 feet above the surface. If still in existence, the
sample-box of the Farnsfield core would be in the hands of the con-
tractors, Messrs. Le Grand & Sutcliff.

Dr. Herpert H. Tuomas, in reply, thought that there was
great difficulty in ascribing a local origin to much of the Triassic
material. ‘The presence of staurolite in such great abundance was
difficult to explain on that hypothesis, and he considered it even
more dangerous to speculate on the nature of rocks completely
hidden by the Trias, than to point to areas known to be capable of
supplying material similar to that of which the Triassic rocks are
composed.

He expressed the opinion that certain minerals mentioned by
the Author, more especially the staurolite, had been derived
directly from metamorphic rocks, and had not before entered into
the composition of a detrital rock.

He felt sure that the Author, if he had been present, would have
been pleased with the reception accorded to the paper, and with the
interesting discussion to which it had given rise.

[December 31st, 1918. |

2D 2

oe
.
i) Pee
B
ee
j

GENERAL INDEX

Pe QUARTERLY JOURNAL

AND

PROCEEDINGS

Acanthopleuroceras rursicosta, nom.
nov., 286-87 & pl. xxvi, 316.

Aclisina (& Aclisoides), notes on, w.
table illustr. their distribution in
Scotland, 59-68.

Aclisina aciculata, 77 & pl. vi.

ashtonensis, 78 & pl. vi.

attenuata, 70.

costatula & var. dubia, 79.

delicatula, sp. nov., 71 & pl. v.

— elegantula, 74-75 & pl. vi.

elongata, 72-73 & pl. v; var,

cingulata, 73 & pl.v; var. varians,

73 & pl. v.

faber, sp. nov., 70 & pl. v.

grantonensis, 76.

—— micula, sp. nov., 71 & pl. v.

— (?) multivolva, sp. nov., 77-78
& pl. vi.

parvula, 75.

polygyra, 73-74.

pulchra, 68 & pl. v ; var. exigua,

nom. nov., 68-69; var. intermedia,

69.

pusilla, 72 & pl. v.

guadrata, 76.

similis, 71-72 & pl. v.

—- striatissima, 75-76 & pl. vi.
subelongata, sp. nov., 74 & pl.

vi.
—— (?) sulcatula, 74.
tenwistriata, 76 & pl. vi.
terebra, 75.
venusta, sp. nov., 69 & pl. v.
Aclisoides (?) armstrongiana, 82.
striatula, 78-81 & pl. vi.
Albitization of rocks, 23-24
Alkalinity, law of increasing, in conn.

OF THE GEOLOGICAL SOCIETY.

w. magmatic differentiation, lxix et
seqq:

Ammonite septum, morphology &
development of the, 26-58 figs. &
pls. itv.

Ammonites birchii, 319-20.

brooki, 321.

bucklandi, 319.

conybeart, 321.

multicostatus, 321-22.

obtusus, 321.

rotiformis, 321.

sauzeanus, 321.

turneri, 321.

Analyses, chemical, of spilitic lavas,
&e., 21-22.

Anatase in Bunter Pebble-Beds, 330.

Anisocardia parvula, sp. noy., 213 &
pl sa:

Annual General Meeting, xiii et segq.

Anodontophora angulata, sp. nov.,
208 & pl. xxi. .

edmondiiformis, sp. nov., 208—

209 & pl. xxi.

ovalis, sp. nov., 208 & pl. xxi.

Arcestes cf. rheticus, 182-83 & pl. xvii.

= SP. (Carnic), 182.

Archean (& Cambrian) igneous rocks
of Britain, & their richness in
sodic felspars, Ixx—Ixxiii.

Arietites turgescens, sp. nov., 296-98
& pls. xxix—xxxi, 316.

Arnioceras anageneticum, sp.
300-301 & pl. xxxi, 316.

—— flavum, nom. nov., 298-300 &
pl. xxxi, 316.

——- fortunatum, sp. nov., 301-302,
& pls. xxviii, xxxi, 316

nov.,

342 GENERAL INDEX.

Ashley County, see Okuku.

Aspidoceras perarmatum, 53 et seqq.
& pl. iv.

Assets, statement of, xliii.

Auditors elected, viii.

Aulacoceras sp. (Trias), 184-85 &
pl. xvii.

Avonian, see Carboniferous Lime-
stone.

Baker, H. A. (& A. M. Davies), on
the Paleozoic Platform beneath
the London Basin & Adjoining
Areas, & on the Disposition of the
Mesozoic Strata upon it [ title only],
viii.

Balance-sheet for 1916, xxxviii—xxxix,

Ball Eye (Derbyshire), spilitic lava
of, 12, 14.

BaRLow-JAMESON Fund awarded to

H. Dewey, lii-liv; list. of re-
cipients, Xxxv.

Barrow, G., 258.

Barrow Hill (Leicestershire), dolo-
mite of, 100.

Bastion Series, 167.

Batusr, F. A., 68; the Triassic Cri-
noids from New Zealand collected
by Dr. C.T. Trechmann, 247-56 figs.

Baton-River Series, 167.

Belemnite animal, recent researches
on the, iv—y.

ennsti ales. recent HEEBINE DE: on,.

vi-viili.

Bibliography of New Harte Trias,
239-40.

BiasBy Medal awarded to R. G.
Carruthers, xlix-l; B. Medallists,
list, of xxesiy.

Bouton, H., 63.

Bonney, T. G., 337.

BoswE.Lu, P. G. H., Wollaston Fund
awarded to, I-h.

Bouuton, W. S., 56.

Bourgquetia (2) arata, sp. nov., 188 &
pl. xvii.

Breedon-on-the-Hill (Leicestershire),
dolomites, &c. of, 94-97.

Breedon Cloud (Leicestershire), Lr.
Carb. of, 97-100 w. plan & pl. ix.
Britain, relat. betw. igneous action &
crust-movements in, lxvii—xcvi.
Brown, C. B., obituary of, lxiv—lxv.
Buckman, 8S. S., Jurassic Chrono-
logy : I—lias, 257-78 figs., 282—

325 figs. & pls. xxvi-xxxi (foss.).

Bunter Pebble-Beds of Nottingham-
shire, microscopic material of, 328—
39 w. map.

Burton, R. C., obituary of, lxvi.

Burton, T. H., the Microscopic

Material of the Bunter Pebble-Beds
of Nottinghamshire, & its Probable
Source of Origin, 328-37 w. map.

esr ge crust-movements, Ixxxi et

eq:

Calle (Derbyshire), Lr. Carb. inlier,
92-93.

Canadian securities, deposited on loan
with H.M. Treasury, xiv.

Caninia cf. patula, 107-108 Bp &
le oes

Caninia Zones on §8.E. margin of 8.
Wales Coalfield, 118, 119, 134-44,
149 et seqq.; C. Oolite, 139-40.

‘Cannon-ball Sandstone’ (Rheetic),
168.

Carboniferons (Lr.) spilites in Derby-
shire, 11-25 w. chem. anals.

Carboniferous Limestone bordering
the Leicestershire Coalfield, 84-110
figs. & pls. vii-xi; C. L. Series on
S.E. margin of 8. Wales Coalfield,
111-64 figs. & pls. xii—xvi.

Cardiomorpha(?2) nuggetensis, sp.
nov., 189-90 & pl. xxi.

Carnic of New Zealand, 167, 169 et

seqq.

CaRR, J. W., 56.

CARRUTHERS, Rs. (Ge Bigsby Medal
awarded to, xlix—l.

Cassianella sp. (Carnic), 206-207 &
play xexae

Castell-Céch Tunnel (Glamorgan),
130.; C. C. Quarry; Vel eso:

Catlin’s-River Series, 167.

Cefn-garw Quarry (Glamorgan), sect.
deser., 152-53.

Cefn On (Glamorgan), 115, 151-52,
154, 159 & pl. xu; vert. & horiz.
sects., 119, 120; Main Limestone
OL elo1. .

Charmouthian, chronology of, 262-68.

Cherts, &c. associated w. Derbyshire
spilites, 17-19.

Cladiscites sp. (Carnic), 183 & pl.
XVil.

Clavigera re-named Hectoria, 216.

Cleistopora Zone on 8.H. margin of S.
Wales Coalfield, 118, 119, 129.

CLouaH, C.T., obituary of, lx—Ixi.

Clydonautilus (Proclydonautilus) cf.
spirolobus, 182 & pl. xvii.

Coed-y-Mochyn (Monmouthshire),
sect. descr. & fig., 124, 127.

Cenothyris sp. (Noric), 218 .& pl.
eau

Couz, G. A. J., 68.

Couuins, J. H., obituary of, lx.

Conjoint Board of Scientific Societies,
xiv.

[vol. Ixxii,

}

part 4]

Conularia sp. (Carnie & Noric), 189
& pl. xviii.

Coronaria spectabilis, sp. nov., 187-
88 & pl. xviii.

Coroniceras bucklandi, 302.

Cosmoceras jason, 53 et seqq. & pl.
iv.

Council, annual report of, xiii—xv ;
(& Officers) elected, xxiv—xxv.

Cox, A. H., award fr. Lyell Fund to,
lii.

Craig Llanishen (Glamorgan), 115,
159 & pl. xii.

Creigiau Fault (Glamorgan), 116 et
seqq., 122.

Crick, G. C., 68; [Recent Researches
on the Belemnite Animal |, iv—v.
Crick Cliff (Derbyshire), spilitic lava

Gites 15,

Crinoidal limestones in Carb. Limest.
Series, 135-36, 1386-38, 143 et seqq.

Croftau (Glamorgan), sect. in quarry
near, 141.

Crust-movements in Britain, relation
between igneous action and, lxvu—
XCVi.

Cunnis, C. G., 86.

Current-bedding in Bunter Pebble-
Beds, 331-33.

Cwm Draethen (Glamorgan), 115, 157
& pl. xii.

Cyathaxonia-rushiana subzone, 103.

Cyathophyllum », zonal significance
of, 141.

* Cycads,’ Mesozoic, recent researches
on, Vi—viil.

Dactylioceras commune, development
of septum, &c. in, 36-45 figs. &

DantiEeEL-PIpGEON Fund awarded to
A. Holmes, xeviii ; list of recipients
of D.-P. Fund, xxxv.

Daoneila indica, 196-97 & pls. xx-
x1.

DARELL, D. S., 286.

Daviss, A. M., 86, 258-59, 292; (&
H. A. Baker), on the Paleozoic
Platform beneath the London
Basin & adjoming Areas. & on
the Disposition of the Mesozoic
Strata upon it [title only], viii.

Dawson, C., obituary of, lxvi.

Deiran, faunal sequence in, 269-70

' w. diagram, 277, 310-11.

Dentalium sp. (Carnic), 188 & pl.
Xviil.

Derbyshire, Lr. Carb. spilites in, 11-—
25 w. chem. anals.

Deroceras bispinigerum, nom. nov.,
294 fig., 302, 303, 316.

GENERAT

INDEX. 343

Devonian (?) in New Zealand, 167.

Dewey, H., Barlow-Jameson Fund
awarded to, lii—liv.

‘ Diabasic ash’ of Okuku, 170, 175.

Diamantiferous garnet-pyroxene rock,
Tx,

Dibunophyllum 6, subzone, bordering
Leicestershire Coalfield, 87 et seqq.,
101; on S.E. margin of S. Wales
Coalfield, 118, 119, 147-48.

Dielasma ef. himalayana, 217.

zealandica, sp. nov., 217-18 &
pl. xxii.

Differentiation, magmatic, & the law
of increasing alkalinity, Ixix et
seqq.

Dimminsdale (Derbyshire), Lr. Carb.
inlier, 95-94.

Diphyphyllum ef. concinnum, 108.

Discophyllites cf. ebneri, 184 & pl.
XVil.

Dixry, F. (& T. F. Sibly), the Car-
boniferous Limestone Series on the
South-Hastern Margin of the South
Wales Coalfield, 111-60 figs. &
pls. xii—xvi, 163.

Dotto, L., 68.

Dolomites in Carb. Limest. bordering
Leicestershire Coalfield, 87 et seqq..
104-105 & pl.x; in C. L. on S.E.
margin of S. Wales Coalfield, 113
et seqq., 186, 138-39, 143-44 et
seqq., 149 et seqq.

Dolomite-mudstone, use of term,117.

Dolomitization im Carb. Limest.
Series on 8.E. margin of 8. Wales
Coalfield, 116-17, 121 et seqq.

Domerian, chronology of, 260—62, 265
(diagram of faunal sequence), 276,
307-10.

Don, A. W. R., obituary of, lxvii.

_ Donors to Library, lists of, xvili—xxi.

DovuviLLE, —, 68.
Dreikanter, see Facetted pebbles.
DuN Lop, R., 63.

Easter Island, physiography, &c. of,
X—Xi.

Ebbw R. (Glamorgan), 111, 125 et
seqg. & pl. xvi (map), 155.

Election of Fellows. iii-iv, ix, xevii,
X¢CVil, c, cli; of Auditors, vii; of
Council & Officers, iii, xxiv—xxv.

ELspDEN. J. V., elected Treasurer, 1ii;
re-elected Treas., xxv.

Ely R. (Glamorgan), 114, 143.

Encrinus hyatti, 248 fig., 251.

Entrochus ternio, sp. nov., 249-52
figs.

—— undatus, sp. nov., 247-49 figs.

344.

Hoanthropus dawsoni, 3-10 fig. &
rolbare

Estimates for 1917, xxxvi—xxxvii.

Ewenny R. (Glamorgan), 111 et seqq.
& pl. xv (map).

Facetted pebbles fr. Pendleton, i-ii.

Faulting in Carb. Limest. of S.E.
margin of 8. Wales Coalfield, 116.

FEARNSIDES, W. G. [delegate to Con-
joint Board of Sci. Soc. ], xiv.

Fellows elected, iii—iv, ix, xevii, xeviil,
c, Cli; names read out, i, iii; number
Ol, Sani xox,

Felspar in Bunter Pebble-Beds, 331 ;
richness of ancient igneous rocks
in sodic felspars, lxxii—lxxili e¢ seqq.

Flag-Hill Series, 167.

Fluorspar in Bunter Pebble-Beds,
329, 335.

Foreign Members, list of, xxvi; For.
Correspondents, list of, xxvii.

Fow ter, F., obituary of, lxvi.

FRANCIS, J., 292.

Garnets in Bunter Pebble-Beds, 329,
335.

Garnet-pyroxene rock, diamantiferous,
1x.

Garth Wood (Glamorgan), 115, 143,
160, & pl. xii.

GARWOOD, E. J., 68.

GEIKIE, Sir ARCHIBALD [presenta-
tion of bust of], ix; re-elected
For. Secretary, xxv; [receives
Wollaston Medal for A. F. A.
Lacroix |, xlv—xlvi.

Gleviceras, gen. nov., 289, 317.

auritulum/glevense, 291-92 &

pls. Xxvili—xxx.

glevense, nom. nov., 289-90 &

pls. xxvili-xxx, 294-95 figs., 317.

riparium, 292 & pl. xxx.

GopMAN, F. DuCang, 10.

Gorpon, W. T. [receives Murchison
Fund for W. Mackie], L—lu.

GOSSELET, J., obituary of, lv—lvu.

Grace Dieu (Leicestershire), Lr. Carb.
of, 100-101.

Groes-faen (Glamorgan), Carb. Limest.
Series betw. Miskin and, 184, 137.

GROVES, J. (& C. REID), Characez
from the Lower Headon Beds [title
only |, iti.

Grypoceras cf. mesodiscum, 181-82.

Guibaliceras, gen. nov., 298, 295 figs.,
317.

GWINNELL,W. F., | exhibits Palzozoic
corals |, ii; [exhibits series of Am-
monites |, XC1x.

GENERAL INDEX.

s

[vol. Ixxin,.

Halobia cf. austriaca, 200-201 &
pol; exccts

hochstettert, 199-200 & pl. xxi.

zittelt, var. zealandica nov...

197-98 & pls. xx—xxi.

spp., 201.

Halorella zealandica, sp. nov., 216—
L72& plexi:

sp. (Carnic), 217 & pl. xxiii.

HaAmuine, J. G., 286.

Hammer-stone fr. Piltdown Gravel,
2-3 fig.

HARKER, A., re-elected President,
xxv; [addresses to recipients of
Medals & Funds], xliv et seqq.:.
[obituaries of deceased Fellows,
&e.], lv-levii; on some Aspects
of Igneous Action in Britain, lxvii—
XeV1.

HawtTREY, R., decease announced,
Ixvil.

Hectoria, gen. nov., 233-85 figs. &
Dl. scx,

— bisulcata, sp. nov., 235-36 &
Dl eacKyv

cuneiformis, Sp. NOv.,

pl. xacve

tumida,
pl. xxv.

Hercynian crust-movements, ]lxxxix
et seqq.

Hettangian, faunal sequence in, 279.

Hinp, W., Lyell Medal awarded to,
xlvii- xlix.

Hokonui Hills (N.Z.), Trias, &c. of,
177-79.

Hokonwia, gen. nov., 202-204 & pls..
XX—XXil.

limxformis, sp. nov., 204-205

& pls. xx—xxil.

rotundata, sp. noyv., 205 & pls.
XX—XXIl.

Houmes, A., Daniel-Pidgeon Fund
awarded to, xevill.

Hoplites auritus, 52 et seqq. & pl. iv.

raulinianus, 53 et seqq. & pl. iv..

splendens, 52 et seqq., & pl. iv.

HueHeEs, T. McK., 63.

Hwiccian, faunal sequence in, 263-66
w. diagram, 276, 310.

237 &

236-37 &

Sp. - now

Igneous action in Britain, relat, betw.
crust-movements and, lxvii—xevi.
Ilmenite in Bunter Pebble-Beds, 330,

304,
IneHAM, F. T., 51.
Isocrinus argenteus, sp. nov., 254.
cwpreus, Sp. nov.,248 fig., 255-56.
gravine, sp. nov., 248 fig., 256.
trechmanni, sp. nov., 248 figs.,,
252.

part 4]

_ Jackson, J. W., [on Facetted Pebbles
from Pendleton (Lancashire) |, i-ii.

Jupp, J. W., obituary of, lvii—lx.

Jurassic of New Zealand, 167 et seqq.;
Jur. chronology: Lias, 257-327 figs.
& pls. xxvi-xxxi (foss.).

Kaihiku Gorge (N.Z.), Trias of, 179;
Kaihiku Series, 167.

Kakanui Series, 167.

Kawhia (N.Z.), Trias, &c. of, 173-74.

Keita, A., {exhibits model of Pilt-
down skull], xevii.

KENWARD, R.., 6.

Keplerites calloviensis, 53 et seqq. &
pl. iv.

Krrcuin, F. L.,, 68, 90, 258.

Knoll-reefs in Carb. Limest. Series,
162.

Knot Low (Derbyshire), spilitic lava
of, 14-15, & chem. anal. on p. 22.

Kocu, W. E., obituary of, lxv.

Lacrorx, A. F. A., Wollaston Medal
awarded to, xliv—xlvi.

Ladino-Carnic, see Carnic.

Lanminosa Dolomite, 118, 121 et seqq.,
138-39.

LampLues, G. W., 258; [obituary
of C. Reid], lxi—lxiv.

Lane, W. D., 31, 56, 258.

LAPwortTH, C., Balston Expedition
to Peru: Report on Graptolites
collected by Capt. J. A. Douglas
[title only], viii.

LapwortH, H.,
retary, XXv.

Lavas, Lr. Carb. spilitic, of Derby-
shire, 11-17, 19-25 w. chem. anals.

Leda semicrenulata, sp. nov., 191 &
pl. xxi.

Len, G. W., 68, 258.

Leicestershire Coalfield, Carb. Limest.
bordering the, 84-110 figs. & pls.
Vii—Xi.

Leptaleoceras, gen. nov., 284-85, 317.

leptum, sp. nov., 285-86 &
pl. xxvi, 317.

Leucoxene in Bunter Pebble-Beds,
330, 335.

LEWER, R. R., obituary of, Ixvi-
Ixvii.

Lias, chronology of, 257-327 figs. &
pls. xxvi-xxxi (foss.); Lr. Lias,
zonal sequence in, 278-81.

Library, annual report of Committee,
xv-xvii; lists of donors to, xviii—
kd,

re-elected Sec-

GENERAL INDEX.

345
Lima (Limatula) ef. pichleri, 206 &

pl. =x.

Llansannor (Glamorgan), 133, 134,
143 ; vert. sect. at, 119; see also
Ruthin.

LonastTaFF, J., Supplementary Notes
on Aclisina De Koninck & Acli-
soides Donald, with Descriptions
of New Species, 59-83 & pls. v—vi.

Lonsdalia floriformis, sub-zone bor-
dering Leicestershire Coalfield, 91
et seqq., 102-1038.

Lower Limestone Shales (Carb.) on
S.E. margin of S. Wales Coalfield,
124-34 w. vert. sect.

LuttTMan-Jounson, H. M. [exhibits
diamantiferous garnet- pyroxene
rock ], ix.

LyrLtL Medal awarded to W. Hind,
xlvii-xlix; L. Fund awarded to
A. H. Cox & T. C. Nicholas, li-—
lii; L. Medallists, list of, xxxi;
recipients of L. Fund, list of, xxxii.

Lymian, faunal sequence in, 273-75,
277, 311-15.

Machen (Monmouth), 115, 116, 153,
159 & pl. xii; vert. sect. on p. 119.

Macxiz, W., Murchison Fund awar-
ded to, li—lii.

Macnarr, P., 63.

McNeiut, BrEpForD, decease an-
nounced, i; obituary of, lxiv. _
Macrodon cf. curionii, 191 & pl. xxi.
Magmatic differentiation & the law
of increasing alkalinity, lxix et

seqq.

Magnetic minerals in Bunter Pebble-
Beds, 329.

Main Limestone (Carb.) on S.E. mar-
gin of S. Wales Coalfield, 134-56 ;
see also Carboniferous Limestone.

Maitai Series, 167, 168.

Malay Archipelago, relat. of Trias to
that of New Zealand, 237-39.

Malay States, MS. geol. map of, xi.

Maps, British geological, as a record
of the advance of geology, c—ci.

Maps illustrating Carb. Limest.
bordering Leicestershire Coalfield,
98, 102 & pl. xi; geol. map of
neighbourhood of Cardiff, 112; of
Carb. Limest. Series betw. Ewenny
& Taff Valleys, pl. xv; of Carb.
Limest. Series betw. Taff & Ebbw
Valleys, pl. xvi; illustratg. occur-
rence of Trias, &c.in New Zealand,
172; illustratg. occurrence of
Bunter Pebble-Beds in Notting-
hamshire, 332.

346

Marr, J. E., [receives Murchison
Medal for G. F. Matthew], xlvi-—
xvi.

MarsHAtt, J. W. D., 303.

MaRrsHAtt, IPS G6:

Masson (Derbyshire), spilitic lava of,
12, 14 & chem. anals. on p. 22.

Mataura Series, 167.

MatruHew, G. F., Murchison Medal
awarded to, xlvi—xlvii.

Mayir-Eymar.C., his stratigraphical
terms for Jurassic succession, 282—
83.

Means, T. DE C., obituary of, lxvi.

Megalodon globularis, sp. nov., 209
& pl. xxi.

Mentzelia cf. ampla, 228 & pl. xxiii,

kawhiana, sp. nov., 228 & pl.
XXxill.

Mentzeliopsis gen. nov.,
pl. xxiii.

horrida, sp. nov., 2380 & pl. xxiii.

spinosa, sp. nov., 2380 & pl.
XM

Mercian, faunal sequence in, 271-73
w. diagram, 277, 311-14.

Mesozoic ‘ Cycads,’ recent researches
on, vi-vill; see also Jurassic.

Mercatern, A. T:, 11.

Micas in Bunter Pebble-Beds, 331,
335.

Microderoceras depressum, nom. nov.,
303-304 & pl. xxx, 317?

inflatum, sp. nov., 305 & pls.

XXVili—-xxix, 317.

229-30 &

rhodanicum, nom. nov., 305-
306, 317.

septigerum, nom. nov., 304 &
pl. xxx, 318:

Millstone Grit bordering Leicester-
shire Coalfield, 86 et seqq.; over-
step of, on S.E. margin of 8. Wales
Coalfield, 123-24, 157, 161.

Miskin (Glamorgan), 114, 116, 134;
vert. & horizont. sects. 119, 120;
sect. deser., 140; quarry N. of,
144, 160 & pl. xiv.

Modiola phases in Carb. Limest. on
S.E. margin of 8. Wales Coalfield,
118, 121 et seqg., 140-41, 145. et
seqq., 153-55.

Monotis salinaria, 195-96 & pls. xix—
xx; var. hemispherica nov., 196 &
pl. xx; var. intermedia nov., 196
& pl. xx.

Moonlight Range (N.Z.), Trias of,
Lede

Moraean, P. G., 166.

Mount Potts (N.Z.), Trias, &c. of,
176.

GENERAL INDEX,

[ vol. lxxin,

Mount St. Mary (N.Z.), Trias, &c. of,
176-77.

Mount Torlesse Annelid Beds, cor-
relation of, 245-46.

Murcuison Medal awarded to G.
F. Matthew, xlvi-xlvii; M. Fund
awarded to W. Mackie, lili ;
Medallists, list of, xxx ; recipients
of M. Fund, list of, xxxi.

Muscovite in Bunter Pebble-Beds, 335.

Myophoria heslingtonensis, sp. nov.,
20d & pli xxi,

nuggetensis,

pl. xxii.

otamitensis, sp. nov., 211 & pl.
Ss

Mytilus (2) mirabilis, sp. nov., 202
& pl. xx.

— (?) problematicus,
plex

sp. nov., 210-11 &

201-202 &

Names of Fellows read out, i, ii.

Nelson (N.Z.), Trias, &c. of district,
174-75.

New Caledonia, relat. of Trias to that
of New Zealand, 237-39.

New Zealand, Trias of, 165-246 w.
map, sects. & pls. xvii-xxv (foss.);
erinoidea fr. same, 247-56 figs.

NicHotas, T. C., award fr. Lyell
Fund to, liii.

Noric of New Zealand, 167, 169 et
seqq.

Normannites braikenridgi, O38 et seqq.
& pl. iv.

Nottinghamshire, microscopic mate-
rial of Bunter Pebble-Beds of, 328—
39 w. map.

Nugget Point (N.Z.), Trias of, 179-
81 w. horiz. sect.

Number of Fellows, xiii, xxii.

Officers (& Council) elected, xxiv—xxyv.

Okuku (N.Z.), Trias, &e. of, 175.

OtpHAM, R. D. [presentation of
books by ], xv—xvi.

Olivine-basalts assoc. w. Derbyshire
spilites, 17.

Oolites in Carb. Limest. Series, 139-
40, 143, 145 et seqg., 149 et seqq.

Oreti Series, 167.

Orthoceras sp. (Carnic), 181 & pl. xvii.

Osgathorpe (Leicestershire), dolomite
of, 100.

Otamita Valley (N.Z.), sect. deser.,
178.

Otapiri Series, 167, 169.

Overstep of Millstone Grit on S.E.
margin of S. Wales Coalfield, 123—
24, 157, 161.

part 4

Oxynoticeras oxynotum, 293, 294-95
figs.
polyophyllum, 293, 294-95 figs.

Pabba Shales, 262-63.

Palzxocardita quadrata, sp. nov., 212
& pl. xxi.

Palzeolith found in British trenches,
ii;. (?) fr. Piltdown Gravel, 2-3
fig"

g.

Palzxoneilo otamitensis, sp. nov., 190
& pls xxi.

ef. preacuta, 190-91 & pl. xxi.

Parsons, L. M., the Carboniferous
Limestone bordering the Leicester-
shire Coalfield, 84-109 figs. & pls.
vii-xi, 110.

Patella (2) nelsonensis, sp. nov., 185
& pl. xviii.

- Pecien sp. (Carnic), 206 & pl. xxi.

Pendleside Shales bordering Leicester-
shire Coalfield, 86 et seqq.

Pendieton (Lanes.), facetted pebbles
from, i-li.

Perisphinctes triplicatus, 51 et seqq.
& pl. iv.

Permo-Carboniferous of New - Zea-
land, 167.

Piltdown Gravel, Hoanthropus, &c.
from, 1-10 figs. & pl. 1.

Pinacoceras sp. (Lr. Noric), 183.

Pinna sp. (Carnic), 206 & pl. xxi.

Pleurophorus zealandicus, sp. nov.,
212-13 & pl. xxi.

Plewrotomaria (Sisenna) hectori, sp.
noy., 186 & pl. xvii.

hokonwiensis, sp. nov., 186-87
& pl. xvii.

Pont-y-Mister, see Coed-y-Mochyn.

Potash-spilites, 25.

PrEstwicH Medallists, list of, xxxiv.

Pseudomonotis ochotica, 193-94 & pl.
xix; var. acutecostata nov., 194 &
pl, 31x,

richmondiana,

194-95 & pl

xx,

Pseudoplacunopsis placentoides, sp.
noy., 209-10 & pl. xxi.

Psiloceras planorbis, 52 et seqq. &
pl. iv.

Psioidea, 215-16.

Putataka Series, 167.

Pycrarr, W. P., 6; [exhibits man-
dibular ramus of Chimpanzee],
xevil, 9.

Quartz in Bunter Pebble-Beds, 329-
30.

GENERAL INDEX.

B47

Raasayan, faunal sequence in, 267-
68, 272 (diagram), 276, 310.

Radstockiceras, gen. noy., 287, 318.

complicatum, sp. nov., 287-88
& pl. xxvi, 318.

Rastelligera, 215.

REED, F. R. C., 68.

REID, C., obituary of, lxi-lxiv; (& J.
Groves), Characeze from the Lower
Headon Beds {title only |, iii.

Retzia schwageri, 227-28 & pl. xxiii.

REYNOLDS, S. H., 68.

Rhetic of New Zealand, 167, 169 et

seqq.

Rhymney R. (Monmouth), 114, 123,
129:

Risca (Monmouth), 111, 114 et seqq,,
121, 124 et seqq.

RITCHIE, —, 63.

Roaring Bay, see Shaw Bay.

Rogson, —, 281.

RosaueEs, H., obituary of, lxv.

ROUTLEDGE, ScorESsBY, [Physio-
graphy, &c. of Easter Island],
xX-X1.

Ruthin (Glamorgan), vert. sect. at,
119; succession in Carb. Limest.
Series at, 121, 148.

Rutile in Bunter Pebble-Beds, 330.

Salter’s Lane (Derbyshire), spilitic
lava of, 14.

SarGeEent, H. C., on a Spilitic Facies
of Lower Carboniferous Lava-Flows
in Derbyshire, 11-23, 24-25 w.
chem. anals.

Scalpa Sandstone, 260, 262.

ScriveENoR, J. B. [presents MS.
geol. map of Malay States], xi.

Seminula Zone on 8.E. margin of
S. Wales Coalfield, 118, 119, 144—
47, 149 et seqq.

Septum in ammonites, morphology &
development of, 26-58 figs. &
pls. li—iv.

Shaw Bay (N.Z.) sect. to Nugget
Point, 180.

SHEPPARD, T., [British Geological
Maps as a Record of the Advance
of Geology], c—ci.

SHERBORN, C. D., (report on pro-
gress of Card-Catalogue ], xvii.

SHIELDS, J. G., 85.

Srpuy, T. F. (& F. Dixey), the Car-
boniferous Limestone Series on the
South-Eastern Margin of the South
Wales Coalfield, 111-60 nee &
pls. xii-xvi, 163-64.

Silurian (Upper), Pin New enlan
icy Gee

348

Simpson, J. C., decease announced,
Ixvu.

Sinemurian, faunal sequence in, 268—
75 w. diagram.

SmitrH, B., elected Auditor, viii.

SmiruH, G. E., on the Form of the
Frontal Pole of an Endocranial
cast of Hoanthropus dawsoni, 7-8.

SmitH, J., 68.

SMITH, S., Aulina retiformis, gen. et
sp. nov., Phillipsastrea hennahr
(Lonsdale), & the Genus Orion-
astrea | published in vol. laait], i.

Sodic felspars, richness of ancient
igneous rocks in, Ixxii-Ixxiii_ et
seqq.

South Head, see Shaw Bay.

South Wales Coalfield, Carb. Limest.
Series on S.E. margin of, 111-64
figs. & pls. xii—xvi.

Special General Meeting, iii.

Sphxroceras brongniarti, septal sec-
tions of, 47-49 figs. & pl. iii.

Spilites, Lr. Carb., in Derbyshire,

" 11-25 w. chem. anals.; use of
terms ‘ spilite, spilitic,’ 23, 24.

Spiriferina acutissima, sp. nov., 221—
22 & pl. xxiv.

ef. austriaca, 224-25 & pl. xxiv.

— (?) caroline, sp. nov., 226-27 &
pl. xxiii.

—— diomedea, sp. nov., 222-28 fig.
& pl. xxiv.

fragilis, 219-20 & pl. xxiv.

gypactus, sp. nov., 221 & pl. xxiv.

kathikuana, sp. nov., 220-21 &

pl. xxiv.

nelsonensis, sp. nov., 223-24 &

pl. xxiv.

otanutensis, sp. nov., 225 &
pl. xxiv.

suesst, var. australis noy., 225—
26 & pl. xxiv.

Spirigera kaihikuana, sp. nov., 231—
o2 & pl. xxv.

manzavinioides, sp. nov., 232—

33 & pl. xxv.

wreyt, 231 & pl. xxv.

Staurolite in Bunter Pebble-Beds,
330-81, 334.

Storms, M. C., [Recent Researches
on Mesozoic Cycads (Bennetti-
tales) ], vi—viil.

STRAHAN, A., 114; [presentation of
bust of Sir A. Geikie], ix; [dele-
gate to Conjoint Board of Sci. Soc. ],
xiv; [receives Bigsby Medal for
R. G. Carruthers], xlix—l.

Strong-room (for Geol. Soc. archives),
xiv.

SWEETING, G. S., 86.

GENERAL INDEX.

[vol. Ixxin,

SWINNERTON, H. H., 337; (& A. E.
Trueman), the Morphology & De-
velopment of the Ammonite Sep-
tum, 26-58 figs. & pls. ii-iv.

Syringopora gigantea, 108.

Taff Valley (Glamorgan), Carb.
Limest. Series betw. Ewenny R. &
Ebbw R. and, 111, 114 et seqq. &
pls. xv—xvi (maps).

Taft's Well Fault (Glamorgan), 116;
vert. sect. at T. W., 119; gorge of

the Taff below T. W., 160 &
pl. xiii.

TALLIN, H. J., 86.

Te Anau Series, 167.

Terebratula cf. hungarica, 219 &
Dl. scxiai,

pachydentata, sp. noy., 218-19

& pl. xxiii.

THomas, HERBERT H., 337; re-

elected Secretary, xxv.

THOMPSON, B., 258.

THomson, J. A., 166.

Ticknall (Derbyshire) Lr. Carb. inlier,
88-92 w. vert. sect. & pls. vii—
vill.

Tideswell Dale (Derbyshire), spilitic
lavas of, 11 et seqqg., 15 & chem.
anal. on p. 22.

Tonge Boring (Leicestershire), 108—
109.

Tongwynlais (Glamorgan), 116, 124
et seqq., 130; vert. sect., 119.

Torlesse, see Mount Torlesse.

Tourmaline in Bunter Pebble-Beds,
330, 334.

Tragophylloceras loscombi, septal sec-
tions of, 45-47 figs. & pl. iii.

TRECHMANN, C. T., the Trias of New
Zealand, 165-245, 246 w. map,
sects., & pls. xvii—xxv (fossils) ;
[Triassic crinoids fr. N.Z. col-
lected by ], 247-56 figs.

Trias of New Zealand, 165-246 w.
map, sects., & pls. xvii—xxv (foss.) ;
crinoidea fr. do., 247-56, figs.; see
also Bunter.

Trochus (Tectus) marshalli, sp. nov.,
187 & pl. xviii.

TruEMAN, A. E. (& H. H. Swinner-
ton), the Morphology & Develop-
ment of the Ammonite Septum,
26-57 figs. & pls. ii-iv.

Trust Funds, statements of, xl—xlii.

Tuffs assoc. w. Derbyshire spilites, 22.

TURNER, C. G., 6.

TURTON, —, 90.

TuTcHER, J. W., 258; the Zonal
Sequence in the Lower Lias, 278—
81.

part 4] °
Uptonia jamesoni, 57 & pl. iv.

VAUGHAN, A., 85, 86.

Via Gellia, see Ball Eye.

Victoriceras, gen. nov., 293, 295 figs.,
318.

Waehneroceras fauna, 280-81.

Wairoa Series, 167, 168, 169.

WARREN, S. H., elected Auditor, viii.

Watts, W. W., 86.

Wessexian, faunal sequence in, 266-—
67, 276, 310.

WHITAKER, W. [exhibits paleolith
found in British trenches ], in.

Whitbian, chronology of, 259-60,
276.

White Lias included in Hettangian,
279, 281.

Witson, G. M. Maryovy, 6.

Wo.uuaston Medal awarded to A.
F. A. Lacroix, xliv-xlvi; W. Fund
awarded to P. G. H. Boswell, l-h;
W. Medallists, list of, xxviii; re-
cipients of W. Fund, list of, xxix.

GENERAL INDEX.

849

Woop, R., 85, 86, 90.

Woops, H., | receives Lyell Medal for
T. C. Nicholas ], liii.

Woopwarp, A. S., 68; [receives
Lyell Medal for W. Hind], xlvii-
xlix; Fourth Note on the Piltdown
Gravel, with Evidence of a Second
Skull of Hoanthropus dawsoni, 1-7
& pl. i.

Worm Wood (Derbyshire), lava of,
15-16.

WRIGHT, J., 68.

Wricuat, T., discussion of ammonites
figured by, 318-23.

Yeovilian,
276.

chronology of, 259-60,

Zaphrentids in Carb. Limest. border-
ing Leicestershire Coalfield, 106.
Zaphrentis Zone (& Lr. Caninia Zone),
on S.E. margin of S. Wales Coal-
field, 118, 119, 134-40, 149 et seqq.

Zircon in Bunter Pebble-Beds, 330,
334,

END OF VOL. LXXITI.

PRINTED BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET,

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will be charged 4s. [Postage 5d.] . lonal Copies

CONTENTS.

PAPERS READ.

Page
9. Mr. S.S. Buckman on Jurassic Chronology : I—Lias (Plates KXVI-XXXI). 257

10. Mr. T. H. Burton on the Microscopic Material of the Bunter Pebble-Beds
om Nothinghamohire sso. 0. eos ert cadena ao ieee Prato. 328

[TirnEz-Pace, Conrents, and Inpex to Vol. LXXIII.]

[The Editor of the Quarterly Journal is directed to make it known to the Public
that the Authors alone are responsible for the facts and opinions
contained in their respective Papers. |

*,* The Council request that all communications intended for publication by the
Society shall be clearly and legibly written on one side of the paper only, with
proper references, and in all respects in fit condition for being
at once placed in the Printer’s hands. Unless this is done, it will be in
the discretion of the Officers to return the communication to the Author for revision.

The Library at the Apartments of the Society is open every Week Day from Ten
o'clock until Five, except on Saturdays (when the hours are from 10 to 1), and
except during the fortnight commencing on the first Monday in September,
when the Library is closed for the purpose of cleaning.

ee

The Secretaries of the Society are desirous of completing a record
of the services rendered by the Fellows in connexion with the present
War. Details of service, with a statement of rank, regiment, military
honours, and any other information, will be gladly received from
Fellows, either with reference to themselves or to those known to them.

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