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QUARTERLY JOURNAL

or the ^

GEOLOGICAL SOCIETY OF LONDON/

EDITED BY

THE PERMANENT SECRETARY OF THE GEOLOGICAL SOCIETY.

Quod si cui mortalium cordi et curse sit non tantum inventis haerere, atque iis uti, sed ad ulteriora penetrare ; atque non disputando adversarium, sed op ere naturam vincere ; denique non belle et probabiliter opinari, sed certo et ostensive scire ; tales, tanquam veri scientiarum filii, nobis (si videbitur) se adjungan t Novum Organum, Traefatio.

VOLUME THE SEVENTY-FOURTH,

FOR 1918. y/

{'mum

%2.

LONDON : ****

LONGMANS, GREEN, AND CO.

PARIS: CHARLES KLINCKSIECK, 11 EUE DE LILLE. SOLD ALSO AT THE APARTMENTS OF THE SOCIETY, MCMXIX.

iUSt

OF THE

OFFICERS

OF THE

GEOLOGICAL SOCIETY OE LONDON.

Elected February 15th, 1918. George William Lamplugb, F.R.S.

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

Prof. William Johnson Sollas,M. A.. Sc.D.,

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

LL.D., F.R.S.

^ecictarteS.

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

CitaSum\

Herbert Hen 17 Thomas, M.A., Sc.D.

jfom'gn J^rcretavn,

Sir Archibald Geikie.O.M., K.C.B.,D.C.L.5 1 James Vincent Elsden, D.Sc LL.D., Sc.D., F.R.S.

Charles William Andrews, D.Sc, F.R.S. Francis Arthur Bather, M. A., D. Sc, F.R.S. Prof. Sir John Cadman, K.C.M.G., D.Sc,

M.Inst.C.E. Arthur Morlev Davies, D.Sc, A.R.C.Sc 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., Iv.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 Lamplugb, F.R.S.

9S0L.

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

Lt.-Col. Henry George Lyons, D.Sc.F.R.S. Prof. John Edward Marr, M.A., Sc.D.,

F.R.S. Richard Dixon Oldham, F.R.S. Robert Heron Rastall, M.A. Prof. William Johnson Sollas, M. A., Sc.D.,

LL.D., F.R.S. Prof. Henry Hurd Swinnerton, D.Sc Sir Jethro J. Harris Teall, M.A., D.Sc.

LL.D., F.R.S. Herbert Henry Thomas, M.A., Sc.D. Samuel Hazzledine Warren. Prof. William Whitehead Watts. M.A.,

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

permanent &tcretai*p.

L. L. Belinfante, M.Sc

£ffirarian. dcrfe.

C. P. Ohatwin. M. St. John Hope.

Sfegfetant in EtOravi).

Arthur Greig.

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

Dr. If. Lapworth, } 0 . .

rj„ tt , , Tr mM } secretaries.

Dr. Herbert II. Thomas.

Dr. P. A. Bather. Prof. Sir John Cad man. Mr. R M. Deeley Dr. .1. V. Elsden'. Prof. E. J. Garwood. Mr. J. F. N. Green. Dr. P. h KitcHn.

Lt.-Col. H. G. Lyons. Mr. R. D. Oldham. Prof. W. J. Sollas. Sir Jethro Teall. Mr. S. H. Warren. Prof. W. W. Watts.

TABLE OF CONTENTS.

Page

Garwood, Edmund Johnston (& Miss E. Goodyear). On the Geology of the Old Radnor District, with special reference to an Algal Development in the \Voolhope Limestone. (Plates I- VII) 1

Holmes, Arthur. The Pre-Cambrian and Associated Rocks of the District of Mozambique. (Plates VIII-XI) 31

Lang, William Dickson. The Kelestominse : a Sub- Family of

the Cretaceous Cribriniorph Polyzoa i204

Morrison, James. The Shap Minor Intrusions. (Plate XIII) .. 116

Oldham, Richard Dixon. A Seasonal Variation in the Fre- quency of Earthquakes. (Plate XII) .... 99

Richardson, Linsoall. The Inferior Oolite and Contiguous Deposits of the Crewkerne District, Somerset. .(Plates XIV- XVI) 145

Sherlock, Robert Lionel. The Geology and Genesis of the

Trefriw Pyrites Deposit 106

Smith, Bernard. The Chellaston Gypsum Breccia in its Relation to the Gypsum-Anhydrite Deposits of Britain. (Plates XVII & XVIII) .......". 174

Stamp, Laurence Dudley. The Highest Silurian Rocks of the

Clun-Forest District, Shropshire. (Plates XIX & XX) 22]

Trueman, Arthur Elijah. The Evolution of the Liparoceratidae.

(Plates XXI-XXV) 247

IV TABLE OF CONTENTS.

PROCEEDINGS. Page

Proceedings of the Meetings i, lxxxi

Annual Report ix

Lists of Donors to the Library xiii

List of Foreign Members xxii

List of Foreign Correspondents xxiii

List of Wollaston Medallists . . . xxiv

List of Murchison Medallists , xxvi

List of Lyell Medallists xxviii

Lists of Bigsby and Prestwich Medallists xxx

Applications of the Barlow- Jameson Fund and Awards from

the Daniel-Pidgeon Fund xxxi

Financial Report xxxii

Awards of the Medals and Proceeds of Funds xl

Anniversary Address of the President li

Cox, Arthur Hubert. On the Relationship between Geo- logical Structure and Magnetic Disturbance lxxxvi

Garwood, Edmund Johnston. [On the Geology of the

Italian FrontJ Ixxxix

Green, John Frederick Norman. On the Igneous Rocks

of the Lake District lxxxi

Heron-Allen, Edward (& J. E. Barnard). On the Appli- cation of X-Rays to the Determination of the Interior Structure of Microscopic Fossils, particularly with reference to the Dimorphism of the Nummulites iv

Mawson, Sir Douglas. On some Features of the Antarctic

Ice-Cap xc

Oswald, Felix. On the Nimrud Crater in Turkish Armenia . i

Smeeth, William Frederick. On the Geology of Southern India, with particular reference to the Archseau Rocks of the Mysore State lxxxiii

LIST OF THE FOSSILS FIGURED AND DESCRIBED IN THIS VOLUME.

Name of Species.

Formal ion.

Locality

Pasre

POLYZOA.

Keledoma gradation, sp. nov..j

fig. 8 J Senonian...

Morphasmopora brydonei, fig.

10 J Cretaceous

jukes-broivnei, figs. 11 &

12 Cretaceous

Riigen

213. 214

215

21(5-17

Ammonoidea.

JEgoccrets (equicoda, sp. no v....

d&dalicosta, sp. nov.,

pi. xxii

nff. lateecoster, pi. xxiii &.

figs. 4-5 Amblycoceras brevilobatum, sp.

nov., pi. xxiv & fig. 10

crescens, pi. xxiv & figs.

0-10

dissotypum, sp. nov.. pi.

xxiii & fig. 10 Aiidrogynoccra.s divariconta, sp.

nov., pi. xxii & fig. 8

obtusicosta, sp. nov., pi.

xxii & fig. 2

Beaniveras spp., pi. xxiii &

fig-3

Bceheiccras bccJici (gen. nov.),

% 13

Cymbites sp., pi. xxiv

Liparoceras cheltiense, pi. xxi

& fig. 4

heterogenic*, fig. 1

obtusinodum, sp. nov..

fig-4

pseudosfr latum, sp. nov.,

fig-4

J'Lias

Lincoln

Dorset

Leek Inn up ton ..

^Lincoln

;

Napton

J

Dorset

Lyme Regis ...

Charlton Kings,

Vaiious

Dorset

275-76 276 273-75 279-80

280-82

282

278-79

1277

265

287-88 291

271 72 j 268 69

I 269

272-73

VI

FOSSILS FIGURED AND DESCRIBED.

Name of Species.

Formation.

Locality.

Page

Ammonoidea (continued).

Liparoceras sparsicosta, sp..^

nov., pi. xxi & fig. 2

tiara, sp. hot., pi. xxi &

% 4

Oistoceras allaeotypum, sp. nov.,

pi. xxv & tig. 12

figidinum, fig. 12 J-Lias.... Various

omissum, pi. xxv & fig.i I

11

Parinodiceras rcincckii (gen.

nov.)

Vicininodiceras simplicicosta,

gen. et sp. nov., pi. xxiv ... /

Various >

265-68

Grotherington ...! Lincoln I

272

287

Various

285

Lincoln

283-85

- Radstock

288-89

^289

Solenopora gracilis, sp. nov., I pi. vi, figs. 1 & 2 1

Sphrsrocodiumgotlandicum . pi. vi, Hgs. '3 & 4 !

AlG/E.

Wool hope Limestone

Aymestry Limestuno

Old Radnor Southern Gotland .

27-28 28

EXPLANATION OF THE PLATES.

Platfs

PaGK

f Conglomerate at tiik Bask op the Woolhope

Limestone, Dolyiiir Quarry; View op Old Radnor Hill, showing Loundary- Faults ; View op Yat Hill, from the old Dolyiiir Quarry, showing Fault-Face; Fault-Plane forming the e a stern boundary op yat I-VII<{ Quarry; Faults at Dolyiiir Quarry and Strinds Quarky; Microscopic Sections op Calcareous Ai.g.e ; and Geological Map of the Old Kadnor Inlif.r, illustrating the paper by Prof. E. J. Garwood & Miss E. Goodyear on the Geologv of the Old Radnor ^ Distric-t .'

>■ 1

VHI-XI^i

f Microscope-Sections op Pre-Cambeian Rocks, ^ etc. ; and Map op the Rikawe Mountains j and the Nrassi Basin, illustrating Dr. A. ! Holmes's paper on tha Pre-Canibrian and f Associated Rocks of tbe District of Mozam- |

^ bique J

31

Plate

fDlAGRAM OF THE DlURNAL AND SEASONAL FRE- ^

quency op Earthquakes in Italy and Japan, |

XIT<( illustrating Mr. R. D. Oldham's paper on )■

a Seasonal Variation in the Frequency of |

^ Earthquakes J

99

XIII

Microscope-Sections of Intrusive Rocks prom the Shap District, illustrating Mr. J. Morri- son's paper on the Shap Minor Intrusions ...

116

P I AT 1 S

( View of Quarky at North Pkkrott Manor ^ House; View op a Portion op the Quarky at i the Misterton Limb- Works; and Views op | XIV XVI { the big Quarry on Ham Hill, illustrating )■ 1-45 Mr. L. Richardson's paper on the Inferior i Oolite and Contiguous Deposits of the Crew- |

^ kerno District

Vlll EXPLANATION OF THE PLATES.

Plates Page

/'Pillar of Gypsum in Chellaston Alabaster^) Quarries; and Microscope-Suctions of An- hydrite and Gypsum from Oocklakes Mine, XVII & XVIII <j illustrating Mr. B. Smith's paper on the )■ 174 Chellaston Gypsum Breccia in its Relation to the Gypsum - Anhydrite Deposits of ^ Britain J

f View of Caer Caradoc, showing Scarp and Dip^ | Slopes; Exposure of Ehynch onella Beds at j XTV %-yyJ Pentre Quarry ; and Geological Map of the I 00, ] Bucknell District, Shropshire, illustrating [ Mr. L. D. Stamp's paper on the Highest ) V Silurian Rocks of the Clun- Forest District ...)

( Liparoceras ; Androgynoceras and Mgoceras ; ^

Amblycoceras and Beaniceras-, Ficikinodi- j

XXI-XXV <( ceras and Cymbites ; and Oisticeras, illus- y 247

I t rating Dr. A. E. Trueman's paper on the |

^ Evolution of the Liparoceratidre J

PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES BESIDES THOSE IN THE PLATES.

Page Fig. 1. Section through quarries south of the railway [Dolyhir] . 24

2. Section through Yat Hill 24

1. Index-map of the district of Mozambique 32

Figs. 2 & 3. Mount Kobe(Meiuba) : proliles seen from the south and

east 36

Fig. 4. Geological sketch-map of the Ampwihi crossing 38

5. Section across the foregoing map 39

6. Sketch-map of the Monapo district 46

7. Granite intrusion : vertical section exposed on the slope

of Mhala (Nakavala) G7

Figs. 8-10. Structures of pegmatites of irregular pipe-like habit : inclined sections exposed on the western slopes of Mhala, Nakavala 69

Fig. 11. Pegmatite intrusion seen in plan across the dry bed of

the Mitikiti River 78

12. Sketch of the Lebi inselberge, Mbulla Range 90

13. Sketch of the Eoldwi inselberge, north of the Mtupa

Pass, Ribawe 91

Map and section, on identical scales, of the Trefriw

pyrites deposit K>^

VOL. LXXIV. b

X PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES.

Page

Fig. 1. Map of the Oewkerne district, showing the localities

where exposures of Inferior Oolite are observed 146

2. Sequence of Inferior-Oolite deposits at Conegar Hill,

Broad Windsor 153

1. Topographical map of the neighbourhood of Ohellaston,

showing the localities where alabaster, etc. has been worked 176

2. Mode of occurrence of alabaster pillars at Ohellaston ... 178

3. Diagram of a typical pillar at Ohellaston 179

4. Masses of white alabaster, with adherent green ' cup,' in

red alabaster, Ohellaston 181

5. Diagrammatic section showing the structure of the

gypsum at Kirkby Thore Quarry 185

6. Pillar of white gypsum in the Subwealden Mine ... 186

7. Section showing the occurrence of "hard stone' (an-

hydrite) at Fauld 194

1. Diagram of a hypothetical Primitive Pelmatoporid 205

2. Diagram of a hypothetical Primitive Kelestomine 207

3. Diagram of an cecium and portions of six others to show

how secondary tissue arises in the intercecial valleys... 208

Figs. 4 & 5. Diagrams representing further development of secondary

tissue in the intercecial valleys 209

Fig. 6. Diagram of the distal end of the cecium of a Pelmato- porid 210

7. Diagram of the distal end of an cecium of a hypothetical

Primitive Kelestomine . 212

8. Diagram of Kelestoma gradatum, sp. nov 214

9. Diagram of the distal end of the cecium of a hypothetical

primitive Morphasmopora 214

10. Diagram of an oecium of Morphasmopora brydonei 215

11. Diagram of an cecium of Morphasmopora jukes-brownei... 216

12. Diagram of ancestrcecium of Morphasmopora jukes-

brovmei 217

1. Geological sketch-map of the Welsh Borderland 2:22

2. Temeside Shales in the old quarry north-north-west of

New Invention 235

PROCESS- BLOCKS AND Ol'HEK ILLUSTRATtVB FIGTRES. XI

Page

F 1. Outline sutures of the principal Liparoceratid genera ... 2o8

2. Sutural development of Liparoceras sparsicosta 266

3. Sutures of Beaniceras spp 266

4. Sutures of Liparoceras spp 270

5. Sutural development of JZfjoceras latcecosta 274

6. Suture of Mgoceras sp 27*3

7. Suture of Androgynoceras obtusicosta 277

8. Sutural development of Androgynoceras divaricosta 278

9. Sutural development of Amblycoceras erescens 281

10. Sutures of Amblycoceras spp 283

11. Sutural development of Oistoceras omissum 284

12. Oistoceras allwotypum and O.Jigulinum 285

13. Sutural development of Becheiceras bechei 288

Dates of Issue of the Quarterly Journal for i918.

No. 293 -May 6th, 1910. No. 294— July 9th, 1919. No. 29.") September 5th. 1919. No. 296 -November 25th, 1919.

Vol. LXXIV.

Part 1.

No- 293.

THE

QUARTERLY JOURNAL

OF THE

GEOLOGICAL SOCIET

EDITED BY

THE PERMANENT SECRETARY.

[With Eleven Plates, illustrating the Paper by Prof. E. J. \ Garwood & Miss Goodyear & Dr. A. Holmes's Paper.] \

Mat 6th, 1919.

LONDON : LONGMANS, GREEN, AND CO.

PARIB:— CHARLES KLINCKBIECK, 11 RUE DE LILLF. 80LD ALSO AT THE APARTMENTS Oir THE SOCIETY.

Price Seven Shillings and Sixpence.

LIST OF THK OFFICERS AND COUNCIL OF THE

GEOLOGICAL SOCIETY OF LONDON.

Elected February 21st, 1919.

:Prt£Siftcnt. George William Lamphigh, F.R.S.

Prof. Sir John Cadman, K.C.M.G., D.Sc, Richard Dixon Oldham, F.E.S.

. M.Inst.C,E. Prof. John Edward F.R.S.

Marr, M.A., Sc.D.,

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

§?tcvctavit$.

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

dfovctcjn J^m-rtari).

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

@<§>iyji

Charles William Andrews, D.Sc, F.R.S. Francis Arthur Bather, M.A., D.Sc, F.R.S. Prof. Sir John Cadman, K.C.M.G., D.Sc,

M.Inst. C.E. Arthur Morley Davies, D.Sc, A.R.C.Sc James Vincent Elsden, D.Sc. Prof. Edmund Johnston Garwood, M.A..

ScD., 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. Robert Stansfield Herries, M.A. George Hickling, D.Sc. John Allen Howe, B.Sc Prof. Percy Fry Kendall, M.Sc

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

James Vincent Elsden, D.Sc

ICIL.

George William Lamplugh. F.R.S. Herbert Lapworth, D.Sc, M.Inst.C.E. Col. Henry George Lyons, D.Sc, F.R.S. Prof. John Edward Marr, M.A., Sc.D.,

F.R.S. Richard Dixon Oldham, F.R.S. George Thurland Prior, M.A., D.Sc

F.R.S. Prof. Henry Hurd Swinnerton, D.Sc. Sir Jethro J. Harris Teall, M.A., D.Sc

LL.D., F.R.S. Herbert Henry Thomas, M.A., ScD. Samuel Hazzledine Warren. Prof. William Whitehead Watts, M.A.

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

permanent Sttrttayv.

L. L. Belinfante, M.Sc?

librarian.

C. P. Chatwin.

Cluit.

M. St. John Hope.

€U4t*tant in Hibiain.

Capt. Arthur Greig.

STANDING PUBLICATION COMMITTEE. Mr. G. W. Lamplugh, President. Dr. H. Lapworth. Dr. Herbert H. Thomas.

Secretaries.

Dr. C. W. Andrews. Dr. F. A.?Bather. Prof. Sir John Cadman. Dr. J. V. Elsden. Prof. E. J. Garwood.

Mr. R. S. Herries. Prof. P. F. Kendall. Col. H. G. Lyons. Mr. R. D. Oldham.

Dr. G. T. Prior. Sir Jethro Teall. Mr. S. H. Warren. Prof. W. W. Watts.

ORDINARY MEETINGS OF THE GEOLOGICAL SOCIETY

TO BE HELD AT BURLINGTON HOUSE.

Session 1918-1919.

1919.

Wednesday, May 7 21*

,, June 4 25*

[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 1917-18.

November 7th, 1917.

Dr. Alfeed Haekee, F.R.S., President, in the Chair.

The List of Donations to the Library was read.

A Lecture on 'The Nimrud Crater in Turkish Armenia* was delivered by Felix Oswald, B.A., D.Sc., F.G.S,

The Nimrud volcano, one of the largest volcanic craters in the world, is situated on the western shore of Lake Van, and was surveyed and investigated geologically for the first time by the speaker in 1898. The western half of the crater is occupied by a deep lake of fresh water, while the eastern half is composed of recent augite-rhyolites, partly cloaked in white volcanic ash. The crater- wall is highest on the north (9903 feet), rising in abrupt precipices over 2000 feet above the lake ( 76-Y3 feet). The southern wall is also precipitous, but only reaches the height of 9434 feet (the south-eastern part). A large slice of the crater- wall has slipped down on the south-west, so as to form a narrow shelf, 800 feet above the lake. The crater is nearly circular, 8405 yards from west-south-west to east-north-east, while the transverse axis is 7905 yards. The lowest points lie on the long axis, reaching only 8139 feet on the western, and 8148 feet on the eastern rim.

The crater-wall has an external slope of 33° on the south and east, where it consists exclusively of overlapping lenticular Hows of augite-rlvyolite and obsidian. On the south-west, west, north-west, and north these are capped by thin sheets of eindery basalt which must have possessed great fluidity, extending for many miles to form wide fertile plains of gentle slope down to Lake Van on the east and into the Plain of Mush on the west. These basalt-Hows

VOL. LXXIT. a

ii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [vol. lxxiv,

clammed up the north-east to south-west valley between the Bendimahi and Bitlis rivers, and thus brought Lake Van into being.

The history of the Niinrud volcano may be summarized as follows from the speaker's observations :

1. Its forerunner was the Kerkur Dagh on its southern flank, a denuded mass of grey augite-trachyte, rising to 9000 feet, and crowned by many peaks. It was probably erupted in the Pliocene Period, subsequently to the folding of the Armenian area, in which the latest folded rocks are of Miocene (Helvetian-Tortonian) age, occurring north of the JS"imrud Dagh and consisting of lime- stones with corals {Gladocora articulata, Orbicella defrancei, etc.), Litliothamnioii, foraminifera (Lepidocycline Orbiioides, Amplii- stegina, etc.), beds of Pecten (_P. urmiensis, etc.) and of oysters {Alectryonia virleti). Nimrud and the other numerous volcanoes of Armenia came into existence at a period when the sedimentary rocks could no longer be folded, but were fractured along definite lines, and Nimrud is situated on the great fracture transverse to the Armenian folds at the apex of their bending round from the Anti- tauric (west-south-west to east-north-east) to the Persian (north- west to south-east) direction. It also marks the point of inter- section of this fracture with a great north-east to north-west fracture (Caucasian direction); which delimits on the south Lake Van and the faulted depression of the Plain of Mush, abruptly cutting off the Tauric horst of pre-Devonian marbles and mica- schists.

2. Numerous flows of augite-rhyolite built up the vast cone of the Nimrud Dagh, and the increasing pressure on the central vent became relieved by extrusions of augite-trachyte along radial fissures, forming the present promontories of Kizvag, Zighag, and Karmuch.

3. A presumably long period of inactivity was followed by violent explosions destroying the summit of the cone, and from this crater (smaller than the present one) vast lava-flows of a very fluid basalt (crowded with phenocrysts of labradorite, pale-green augite, and some olivine) flooded the country, filling up the Bitlis and Akhlat valleys, which have since then been eroded a little below their former depth. The Sheikh-Ora crater of basic tuff (now breached by Lake Van) probably belongs to this period.

4. Further explosions widened the crater, in which a large lake was formed ; while the eastern half of the crater became filled by a succession of outflows of augite-rhyolite, in which numerous blow- holes were drilled, bringing to the surface large blocks of basaltic agglomerate, and also affording sections that show the transition downwards from obsidian, spherulitic obsidian, and spherulitic rhyolite to banded augite-rhyolite (with sanidine and green augite in a nlicropcecilitic ground-mass).

5. The last eruption was recorded in 1441 by a contemporary Armenian chronicler, and resulted in the extrusion of a very viscous augite-rhyolite along a north-to-south zone of weakness, both inside

part 1] PROCEEDINGS OF THE GEOLOGICAL SOCIETY". Hi

the Nimrud crater, where it separated off part of the large lake to form the shallow, so-called ' hot lake/ and also north of Nimrud, where it rose up through fissures and in a small crater.

6. A violent earthquake in 1881, which destroyed the village of Teghurt, at the eastern base of the crater-wall, was the last sign of activity : but earthqun kes are still frequent in the Plain of Mush, at the western foot of the Nimrud Dagh, and recent fault-scarps are clearly visible along the borders of this faulted depression.

The speaker mentioned that he had presented his model of the crater to the Museum of Practical Geology (Jermyn Street ) and the rock-specimens and microscope-slides to the British Museum (Natural History), where his fossils from Armenia are already preserved.

A short discussion followed, and the thanks of the Fellows present were accorded to Dr. Oswald for his lecture.

Lantern-slides of many unpublished photographs and drawings of the Nimrud Crater and its surroundings, a model coloured geologically on the scale of 1 inch to the mile, and a scries of rock-specimens and rock-sections were exhibited by Dr. Oswald, in illustration of his lecture.

A Geological Survey map of the Maclean- Umtata district, Cape Province, Sheet 27. scale: 1 inch=3'75 miles. 1917 (presented by the Geological Survey of the Union of South Africa), was also •exhibited.

November 21st, 1917.

Dr. Alfred Harkeu, F.K.S., President, in the Chair.

The List of Donations to the Library was read.

The following communication was read :

'The Shap Minor Intrusions.' By James Morrison, B.A., JB.Sc. (Communicated by Dr. Herbert Lapworth, Sec.G.S., M.Inst.C.E.)

Diagrams, rock-specimens, and microscope-sections of the Shap minor intrusions were exhibited by Mr. Morrison, in illustration •of his paper.

A Geological & Topographical Atlas of the Gympie Goldfield -and Environs, in 36 sheets, scale 1 : 4-7-32. 1910-1911 (presented by the Queensland Geological Survey) was also exhibited.

a2

iv PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [vol. lxxiv,.

December 5th, 1917.

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

Thomas Robert Ablett, Pembroke Lodge, Outram Road, Addis- combe (Surrey) ; John Albert Bullbrook, 15 Abercromby Street, Port of Spain, Trinidad (B. W. I.) ; Charles Herbert Henry Gore,. 69 Eastcott Hill, Swindon (Wiltshire) ; George Thomas Heal, A.M.Inst.M.M., care of the High-Speed Steel Alloys, Ltd., Tavoy (Burma); William Blomfield Hume. B.Sc, United B. W. I. Petroleum Syndicate, Port of Spain, Trinidad (B. W. I.) ; Francis Sear Jolly, 14 Allerton Road, Stoke Newington, N. 16 ; William McDonald, 53 Dalzell Street, Moor Kow (Cumberland) ; Stephen Miall, LL.D., B.Sc, 28 Belsize Grove, N.W. 3 ; Evan John Morris, Llwyncelyn, Bangor (North Wales) ; Clive Edward Effingham Pargeter, A.M.Inst.M.M., Westbrook House, Hounslow (Middlesex) ; Sir John Frecheville Ramsden, Bart., Bulstrode,. Gerrard's Cross (Buckinghamshire) ; Albert Ernest Thomas,. M.Inst.M.M., Oak House, Minsterley, Shrewsbury ; and Arthur- Elijah Trueman, M.Sc, 598 Berridge Road, Nottingham, were- elected Fellows of the Society.

The List of Donations to the Library was read.

A Demonstration on the Application of X-Rays to t he- Determination of the Interior Structure of Micro- scopic Fossils, particularly with reference to the Dimorphism of the Nummulites, was given bv Edward Heron-Allex, F.L.S. F.G.S., Pres.R.M.S., and J. E.' Barxard, F.R.M.S.

Mr. Herox-Allex said that, in the year 1826, Alcide d'Orbignv published among the innumerable, and for many years unidentified, nomina inula that compose his 'Tableau Methodique de la Classe des Cephalopodes ' the name Mot alia (labia. This species was left untouched by Parker & Jones in their remarkable series of articles on the ' Nomenclature of the Foraminifera.' The French naturalist G. Berthelin was the first investigator to unearth and make use of the ' Planches inedites ' which had been partly com- pleted by D'Orbignv ibr the illustration of his great work upon the Foraminifera, a work that was never published. Working with Parker & Jones's paper, Berthelin made for his own use careful tracings of 246 of A. d'Orbigny's unfinished outline- sketches. These sketches were never elaborated by D'Orbignv upon the ' Planches,' which are still preserved in the Laboratoire de Paleontologie under the care of Prof. Marcellin Boule ; among them was found the sketch of Mo/alia (labia. On the death of Berthelin the tracings passed into the possession of Prof. Carlo Fornasini of Bologna, who reproduced them all in a valuable series of papers published between the years 1898 and 1908. Fornasini's opinion

part 1] PEOCEEDTXGS OF THE GEOLOGICAL SOCIETY. V

whs that the organism depicted by D'Orbigny was doubtfully of Ehizopodal nature, and that it was probably referable to the Ostracoda. The speaker said that he had examined the D'Orbigny type-specimens in Paris in 1914, and had noted that Rotalia dubia

was a worn and unidentified organism, resembling an ostracod.

There the matter rested, until Mr. Arthur Earland and the speaker, while examining the material brought by Dr. J. .). Simpson from the Kerimba Archipelago (Portuguese East Africa) in 1915, discovered one or two undoubted foraminifera of an unknown type, which resembled Berthelin's tracing. Prof. Boule kindly sent the D'Orbigny type-specimen to London, and the Rhizopodal nature of Rotalia dubia was established. It is not a Rotalia, and it must await determination until more specimens are obtained : it has been named provisionally Pegidia papillata. There were two or three forms of the organism, but only one perfect specimen of the D'Orbigny type : and it was undesirable to risk destruction by cutting a section of it. In these circumstances Mr. Barnard was approached, and he experimented with the object of ascertaining the interior structure of the shell by means of the X-rays. His results were extraordinarily promising, and led to further experiments.

The speaker showed on the screen photographs of the common and dense foraminifer Massilina secans (D'Orbigny), followed by a skiagraph of the same. A skiagraph of the still denser test of Bilo- eulina bulloides D'Orbio-nv shows the arrangement of the earlier chambers as clearly as it is indicated in Schlumberger's beautiful sections. The application of X-rays to the dense imperforate shells of Corny spi ra fol iacaa i Philippi) produced skiagraphs showing the dimorphism of the shells, both megalo- and microspheric primordial chambers beino' clearly distinguishable. Such results led to the extension of the experiments to the agglutinated arenaceous forms, of which sections are made with extreme difficulty. The skiagraph of Astrorliiza a ran aria Xorman shows the internal cavities that contained the j^rotoplasmic body. Two arenaceous forms, Botellina labyrinthica Brady and Jar alalia obtusa Brady, that are almost identical in external appearance, are distinguished at once by their respective skiagraphs, the one exhibiting a simple tubular cavity, the other appearing labyrinthic.

Mr. Barnard subsequently experimented on still more difficult material. The massive Operculina complanata Defrance, the umbilical portion of which is obscured by a mass of secondary shell-substance, furnished a clear skiagraph that showed some curious distortions of the internal septa. Similar results wrere obtained in the case of Orbiculina atlunca (Fichtel & Moll), another species overladen with shell-matter. Cyclammina can cell 'a la Brady is an arenaceous form, composed of softer mud and sand, studded with coarse sand-grains which make section -cutting almost an impossibility. The skiagraphs, however, reveal the primordial chamber, and establish the character of this form.

The determination of the Xummulites, depending as it does on a knowledge of the internal structure of the test, is greatly

VI PROCEEDINGS OE THE GEOLOGICAL SOCIETY. [vol. lxxiv,.

facilitated by the application of X-rays, which removes the necessity of splitting the test or cutting sections through it.

The speaker showed ordinary photographs and skiagraphs, made at slightly varying azimuths, of Nummulites laevigata and JV. variolaria, forms that strew the shores of Selsey Bill. A particularly notable result was obtained in the case of iV7. gizek- ensis, an organism that forms the dense masses of Nummulitic Limestone of which the Pyramids of Egypt and the Citadel at Cairo are built.

Mr. Barnard said that, although the utilization of X-rays to determine the internal structure of various bodies was well known, he was not aware that the method had been successfully applied to small objects, sucli as foraminifera. After he had begun his ex- periments he found that M. Pierre Groby had done some work in this direction in Prance, but the method as Goby described it is surrounded with considerable mystery and elaboration of apparatus, which appear quite unnecessary. The speaker's results were arrived at independently ; in fact, they are really a side issue.

His original experiments were directed rather towards the use of X-rays in obtaining magnified images, altogether apart from the usual skiagraphic methods in which a shadowgraph is, in fact, all that can be produced. The primary object has not yet been achieved, although there is some reason to hope that it may ultimately come to pass. The results shown by Mr. Heron-Allen are obtained by quite simple means. A very narrow beam of X-rays, such as would be termed ' a parallel beam ' when speaking in terms of ordinary light, is allowed to impinge on the object, the latter being in contact with the photographic plate. The negative produced is, therefore, of the same size as the object. Photographic enlargement is then resorted to, and the result had been shown on the screen.

There are two points that require careful attention if success is to be achieved. The qualit}r of the X-rays must be suited to the object. In nearly all cases of small objects, what are known as 'soft' X-rays must be used, and the degree of softness is the crux of the whole matter. The photographic plate must be of exceedingly fine grain, otherwise the amount of enlargement that can be obtained is very limited. Difficulties in this direction have been overcome, and Mr. Heron-Allen states that the results are of considerable biological value.

A short discussion followed, and the thanks of the Fellows present were accorded to Mr. Heron-Allen and Mr. Barnard for their demonstration.

Dr. A. Smith Woodward, F.R.S., V.P.Gr.S., exhibited a radio- gram of the original slab of lithographic stone containing the skeleton of Archceopteryx, made for the British Museum by Dr. Robert Knox in 1916. It was evident that the penetrability of the fossil bones to the X-rays was the same as that of the

part 1] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. vil

surrounding matrix. The only portions of the skeleton visible in the radiogram were those more or less raised above the general surface of the slab. This result accorded with that obtained by Prof. W. Branca, when he similarly experimented with the Berlin specimen of Archadopteryx.

December 19th, 1917.

Dr. Alfred Habker, F.R.S., President, in the Chair.

The List of Donations to the Library was read.

The following communication was read :

' The Chellaston Gypsum-Breccia considered in its Relation to the Gypsum- Anhydrite Deposits of Britain.' By Bernard Smith, M.A., F.G.S.

Lantern-slides, rock-specimens, and polished slabs of alabaster were exhibited by Mr. Bernard Smith, in illustration of his paper.

January 9th, 1918.

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

The List of Donations to the Library was read.

The following Resolution of the Council was unanimously approved by the Fellows present. It was further resolved that a copy be forwarded to the Prime Minister :

The Council of the Geological Society has learned with surprise and regret of the proposal of the War Cabinet and the Office of Works to dismantle the British Museum at Bloomsbury and its Natural History Branch at South Kensington, in order to convert the buildings into ordinary piTblic offices. It desires to protest most strongly against this unfortunate blow to the cidtivation and progress of learning in the Empire, and earnestly hopes that the Government's intention may be reconsidered. The Geological and Minera logical Collections, of which the Geological Society has special knowledge, are continually needed for reference concerning numerous problems that arise in the present crisis, and they cannot be rendered inaccessible without danger to their preservation.

The following communication was read :—

' The Highest Silurian Rocks of the Clun-Forest District (Shropshire).' By Lawrence Dudley Stamp, B.Sc, A.K.C.L. (Communicated by Dr. A. H. Cox, F.G.S.)

Specimens of rocks and fossils from the Silurian of the Clun- Forest district were exhibited on behalf of Mr. L. D. Stamp, in illustration of his paper.

viii PROCEEDINGS OE THE GEOLOGICAL SOCIETY. [vol. lxxiv.

January 23rd, 1918.

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

Frederick George Jones, 33 Royal York Crescent, Clifton, Bristol; Sir Douglas Mawson, D.Sc, B.E., The University, Adelaide (South Australia) ; Nagardas Purushottam Gandhi, M.A., B.Sc, A.R.S.M., D.I.C., Wolfram Mines, Tavoy (Burma) ; George Turner Reeve, M.A., 79 St. John's Avenue, Bridlington (Yorkshire) ; Alfred Ulrich Max Schlaepfer, Doctor of Technical Science (Zurich, Switzerland), 12 Arlington Gardens, Chiswick, W.4 ; and Lawrence Dudley Stamp, B.Sc, A.K.C.L., Passey's House, Eltham, S.E. 9, were elected Fellows of the Society.

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 preceding year: R. Mouisteord Deeley, M.Inst.C.E., and Bernard Smith, M.A.

The following communication was read:

'On a Flaked Flint from the Red Crag.' By Prof. William Johnson Sollas, M.A., Sc.D., LL.D., F.R.S., V.P.G.S.

A specimen of a flaked flint from the Red Crag of Messrs. Bolton & Company's Pit at Ipswich was exhibited by Prof. W. J. Sollas, in illustration of his paper.

February 6th, 1918.

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

James Arthur Butterfield, M.Sc, 59 Barrett Street, Shipley (Yorkshire) ; and Lieut. Frederick Stretton Wallis, 9 Woiferton Road, St. Andrews, Bristol, were elected Fellows of the Society.

The List of Donations to the Library was read.

The following communication was read :

' Some Considerations arising from the Frequency of Earth- quakes.' By Richard Dixon Oldham, F.R.S., F.G.S. *

Diagrams were exhibited by Mr. R. D. Oldham, in illustration of his paper.

ANNUAL GENERAL MEETING.

February 15th, 11) lb.

Dr. Alfred Haekee. F.R.S., President,

in the Chair.

Report of the Council fur 11)17.

During the year under review. 32 new Fellows were elected into the Society i 2 less than in 1916^ and 3 Fellows were re-admitted after payment of arrears. Of the Fellows elected in 1917, 23 paid their Admission Fees before the end of that year, and of the Fellows who had been elected in the previous year (5 paid their Admission Fees in 1917. making' the total accession of new Fellows during the past year amount to 29 (5 less than in 191(3).

Allowing for the loss of 43 Fellows (8 resigned, and 35 deceased), it will be seen that there is a decrease of 11 in the number of Fellows, as compared with a decrease of 32 in 1916.

The total number of Fellows is. therefore, at present 1220, made up as follows: Compounders 216 (10 less than in 1916); Contributing Fellows 989 (1 less than in 1916) ; and Non- Contributing Fellows 15 (the same as in 1916).

Turning now to the Lists of Foreign Members and Foreign Correspondents, the Council has to regret the loss during the past year of Dr. H. E. Sauvage and Dr. W. B. Clark, both Foreign Correspondents. It will be remembered that, in the List of Foreign Members at the end of 191(5, there were four vacancies, and six 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 eight vacancies in that of Foreign Correspondents.

With regard to the Income and Expenditure of the Society during 1917, the figures set forth in detail in the Balance-Sheet may be summarized as follows : The actual Receipts (excluding the Balance of £676 12s. 5d. brought forward from the previous year) amounted to £2966 10*. 8rf., being £413 10s. Sd. more than the estimated Income.

On the other hand, the Expenditure during the same year, including the outlay of £47-3 for £-500 5 % War Loan, amounted to £3581 Is. (5d., being £-553 Is. tid. more than the estimated Expenditure, and the A'ear closed with a Balance in hand of £62 Is. Id.

Early in the year the Council decided to recommend the expenditure of the proceeds of the Sorby and Hudleston Bequests in fitting up the Meeting-Room Annexe as a Map-Room. Plans were prepared, and estimates obtained : but, on the advice of the

X PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [vol. lxxiv,.

Architect H.M. Office of Works, the work was postponed until ' after the War.

With regard to the publications of the Society, the Council has to announce the completion of Vol. LXXII of the Quarterly Journal (1916). No. 20 of the Society's 'Record of G-eological Literature ' (1913) is now in the printers' hands.

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 49 Fellows serving with His Majesty's Forces (18 more than in 1916).

During the past year the Apartments of the Society have been used for General and for Council Meetino;s bv 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, the Mineralogical Society, the Paheontographical Society, the Ray Society, the South-Eastern Union of Scientific Societies, and the Geological Physics Society.

Dr. A. Strahan and Prof. W. G. Fearnsides have continued to act during the year as our representatives on the Conjoint Board of Scientific Societies.

The fifteenth Award from the Daniel Pidgeon Trust Fund was made on March 28th, 1917, to Arthur Holmes, B.Sc, who proposed to conduct researches in connexion