H : No. 3 ~ . ~

t~

V o l . - L ~ . P SRT 1.

TI~IE

QUARTE It LY J 0 U R N A L

oF THtz

G E O L O G I C A L SOCIETY. ~} '

�9 D I T I ~ D B Y

TH ~ PERMAhE~T 8F, CRg'_rARY. ~

MxRc~[ 17tt~, 1926. (

(

[Witll Six Plates, t l lus~ating Papers by Miss J. X. M. Diagwall, Kr. W. L. F. Nu~Call, and Xr. W aLmpodl sma~.j

LONDON :

LO_NUMANS, ~ R E E N , & GO. LTD

r&RI8 ...-OHARI~8 KLINCKSIBCK, 11 RU~ DE LILLE.

BOLD ALSO AT THE APARTMENTS OF THE SOCIETY.

Pmc, e JSeven 5'/albngs and ,Yizpene~.

~ ~ .

LIST OF THE OFFICERS AND COUNCIL OF THE

/ EOLOGICAL SOCIETY OF LONDON. Elected Fbbruary 19th. 192G.

~d~L ~l~CikL. A L!~ur Francis Bather, ~.A., ~.3~., F.R.3.

Joh~ William E~ans, C.B.E., D.Sc., Horace vVoolJaston Monckton, Treas.l,S. LL.B., F.I~.~. ~ir Arthur ~tmth Woodward, LI~.I).,

Sir Thomas Henry Holland, K.C.~.I., F.~.5., F.L.o. K.C.I.E., D.:+c., F.I+.S.

Wal~er Campbell Smith, M.C., M.A. I James Archibald Douglas, M.A., D.Sc

;ifar+tgn 9¢cr+tat 'p . ~ r+a+ur+n Prof. John Edward Marr, M.A., Sc.D., I~obert Stansfield Herries, M.A.

F.~.S.

Dr. Arthur Francis Bather, M.A., F.R.S. Prof. Arthur Hubert Cox, D.Se., Ph.D. Thomas Crook. Henry Dewey. James Archibald Douglas, hLA., D,Sc. Gertrude Lilian Elles, M.B.E., D.Sc. john William Evans, C.B.E., D.Sc., LL.B.,

F.I~.S. Prof. William George Fearnsides, M.A. Prof. Edmund Johnston Garwood, M.A.,

Sc.D., F.R.S. Prof. William Thomas Gordon, 1Vf.A.,

D.Se., F.R.S.E. Dr. Edward Greenly. Prof. Herber~ Leader Hawkins, D.Se.

Robert Stansfield Herrles. M.A. Sir Thomas Henry Holland, N.C.S.I.,

K.C..LE., 1).So., F:I~.S. Dr. Finlay Lorimer Kitchin, M.A. Prof. John Edward Marr, M.A., Sc.D.,

F.t~.S. Horace Wool]astou Monckton, Treas.L:S. Tressilian Charles Nicholas, O.B.E.,

M.C., M.A. John Pringle. Walter Campbell Smith, M.C., M.A. Leonard James Spencer, M.A., Sc.D. Arthur Elijah Trueman, D.Sc. Sir Arthur Smith Woodward, LL.D.,

F.I~.S., F.L.S.

L. L. Be l in fante , l~q.Sc.

O . ~ t l ' d l ' l , a l , .

Arthur Greig. _

S t'AN DINtJ PU ~tLICATION O O M M I T T E ~ . Dr. F. A. Ba%her, President.

Mr. W. Campbell Smith. t Secretaries. Mr. R. S. Herries, Treasurer. Dr. J. A. Douglas.

~ r . T. Crook. Prof. J. E. Marr. Prof. W. XV. ~v,+÷~. Prof. W. G. Fearnsides. Mr. T. C. Ni(.holas. Sir Arthur Smith Wood- Prof. E. J. Garwood. Dr. L. J. Spencer. ward. Prof. H. L. Hawkins. Sir Aubrey S~rahan.

O R D I N A R Y M E E T ] P ~ G S 01+' r ~ l E S E O L O G I C A L S O C I E T Y TO BE HELD AT BURLINGTON HOUSE.

SESSION 1 9 2 5 - 1 9 2 6 . 1926.

Wednesday, March . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 a ,, April . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 ~ ,, May . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - - 19 ~

J u n e . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 ~ - - 2 3 ,}

The asterisks denote the dates on which the Council will meet.

JAMES SWIFT & SON L TD, Makers of the Highest Grade

MICROSCOPES AND ACCESSORIES (M~tr. , '~ ' . . ."M i r l f N,'ie. ti,lic l;elu(~t,~e,~t~ or H.3I. (iu~er. tr~e,~t.

Petrological Microscopes " P r i m e x , " " A d v a n c e d S t u d e n L " " P e ~ r o s , " " S u r v e y " a n d " D i c ~ " ~ o d e l s i b r a l l c l a s s e s o f ~ e t r o l o g i e a l a n d N [ i n e r a i o g i c a l R e s e a r c h .

Petrological Accessories a n d I n s t r u m e n t ~ o r M [ i n e r a l o g y a n d C r y s t a l - l o g r a p h y , i n c l u d i n g R o f r a e t o m e ~ e r s , G o n i o -

m e t e r ~ , R e c o r d l a ~ I ~ J c r o m c t e r - , e t c .

[ll~strated Descriptive C,~talo.ques o,~ req~,est. ' " 4 d ~ a n c e ] S t u , ] e , ~ t '

Univers i ty Opt ical W o r k s 81 T O T T E N H A M COURT ROAD~ LONDON.

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L e i t z P r i s m B i n o c u l a r s .

CONTENTS.

Pages Proceedings of the Geological Society . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i-xliv

PAPERS READ. Page

1. Prof. W. J. Sollas on a Sagittal Section of the Skull of Austratopithecus

africanus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2. Miss J. 1K. l~. Dingwall on Cyathoc~isia taber~tacuh~m gen. et sp. nov.

(Plates I - I I I ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3. h{r. W. L. F. Nut ta l l : a Revision of the Orbitoides of Christmas Island

(Plates IV & V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4. Mr. W. Campbell Smith on the ¥olcanic l~ocks of Christmas Island

(Plate VI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

5. Mr. R. D. Oldham on the Depth of Origin of Earthquakes . . . . . . . . . . . . . . . . . . . . . . . . 67

6. Mr. W. l~. Edwards on Fossil Plants from the Nubian Sandstone of Eastern

Darfur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

[The Editor of the Quarterly Journal is directed to make it known to the Public

that t h e A u t h o r s a l o n e a r e r e s p o n s i b l e f o r t h e f a c t s a n d o p i n i o n s

a o n t a i n e d in t h e i r r e s p e c t i v e P a p e r s , a n d f o r t h e c o r r e c t n e s s of

t h e i r r e f e r e n c e s . ]

A u t h o r s d e s i r o u s of c o m m u n i c a t i n g p a p e r s to t h e S o c i e t y w i l l be

s u p p l i e d , on a p p l i c a t i o n t o t h e S e c r e t a r y , w i t h a c o p y of

' I n s t r u c t i o n s t o A u t h o r s ' , i s s u e d b y t h e C o u n c i l on ~he r e c o m -

m , e n d a t i o n of t h e P u b l i c a t i o n C o m m i t t e e .

The Library at the Apartments of tile Society is open every Week Day from Ten

o'clock until Five, except on Saturdays (when the hours are from 10 to i) , and

except during the fortnight commencing on the first Monday in September,

when the Library is closed for the purpose of cleaning.

r t .o 6

V o l . L X X X I I . I'AZtT 2.

N o . 32,6.

THE

Qt U A RT E it L Y J O URNA I~

OF T ~

GEOLOGICAL SOCIETY.

BDITmD BY

THE PERMANENT SECRETARY.

JULY 3rd, 1926.

[With Fif[een Plates, illustrating Papers by Prof $. E. Marr, Dr. W. D. Lang �9 Dr. L. F. Spath, Dr. D. Parkinson, Mr. T. 0. Morris & Prof. W. G. Fearnsides, and Dr. G. L. EUes.]

"Is

LONDON :

LONGMANS, GREEN, & CO. LTD.

pAR|S:-- .@HARLEw KLINCKSIECK, 11 RUI$ D E ~ILLE.

S O L D ALSO AT T H E A P A R T M E N T S O F T H E S O C I E T Y .

Price ~eve~ ~t,~il~g8 and Nixpe~ce.

LI~T OF THE OFF1CERS AND COUNCIL OF TitE

GE()I OGICAL SOCIETY OF Elected ~ i ; ~ Y9~, 1926.

Francis h r thur Bather, M.A., D.Sc., F.R.S.

John William Evtms, O.B.E., D.Sc., Horace Woollas~onMonckton, Treas.L.S. LL.B., F.I~.S. Sir Arthur ~mi~h Woodward, LL.D.,

Sir Thomas Henry Holland, K.C.q.I., F.R.S., F.L.S. K.C.I.E., D.Sc., F.I~.S.

.~ tcr ttar~t~. Wal~er Campbell Smith, M.C., M.A. I James Archibald Douglas, M.A., D.Se.

~0rtq~n .~ t t r t tarp . ~ rta~urtr. Prof. John Edward Marr, M.A., Sc.D., ICobert Stansfield Herries, M.A.

F.I~.S. ~ - ~ © ~ L .

Francis ArthurBather , M.A.,l).Se.,F.ILS. Sir Thomas Henry Holland, K.C.S.I., Prof. Arthur Hubert Cox, D.Sc., Ph.D. Thomas Crook. Henry Dewey. James Archibald Douglas, M.A., D.So. Gertrude Lilian Elles, IVI.B.E., D.Sc. John William Evans, C.B.E., D.Sc., LL.B.,

F.I¢.S. Prof. William George Fearnsides, M.A. Prof. Edmund Johnston Garwood, M.A.,

Sc.D., F.R.S. Prof. William Thomas Gordon, M.A.,

D.Sc., F.IC.S.E. Edward Greenly, D.Sc. Prof Herbert Leader Hawkihs, D.Sc. l~obert Stansfield Hermes, M.A.

K.C.I.E., D.Sc., F.g.S. Finlay Lorimer Kitchin, M.A., Sc.D. Prof. John Edward Marr, M.A., Sc.D.,

F.R.S. Horace Woollaston Monckton, Treas.L.S. Tressilian Charles Nicholas, O.B.E.,

M.C., M.A. John Pringle. Walter Campbell Smith. M.C., M.A. Leonard Jau,es Spencer, M.A., ~c.l~.,

F.R.S. Arthur Elijah Trueman, D.Sc. Sir Arthur Smi%h Woodward, LL.D.,

F. I~.S., F.L.S.

~mnmm~t ~crr tarp. L. L. Belinfante, M.,qc

~lbrartan. Arthur Greig.

S T A N D [ N O P U B L I C A T I O N GOMMITTEE. Dr. F. A. Bather, President.

Mr. W. Campbell Smith. Dr. J. A. Douglas. j Secretaries. Mr. [~. S. Herries, Treasurer.

Mr. T. Crook. Prof. J. E. Marr. Prof. W. W. Watta. Prof. W. G. Fearnsi]es. Mr. T. C. Ni,.holas. Sir Arthur Smith Wood- Prof. E. J. Garwoo~l. Dr. L. J. Spencer. ward. Prof. It. L. H ~wkins. Sir Aubrey Strahan.

O R D I N A R Y M E E T I N G S O F T H E G E O L O G I C A L S O C I E T ~ TO BE HELD AT BURLINGTON HOUSE.

.~ I,:SSI~)N 1926-1927 . 1926.

Wednesday, November . . . . . . . . . . . . . . . . . . . . . . . . . . . 3~--17 # December . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 --15 ~

1927. Wednesday, January . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5v--19 v

,, February (Anniversary Meeting, Friday, February 18th) . . . . . . . . . 2~--23 v

,, March . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 ---23 v ,, April . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6v--27 ,, May . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 v - 25

June . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 # Th~ asterisks denote the dates on which the Council will meet.

JAMES SWIFT SON U p, M a k e r s o f t h e H i g h e s t G r a d e

HICROSCOPES AND ACCESSORIES Contr_ac'tors to alt Scientific Depar~rne~ts of H.M. GovernmenL

'" Advance~ Student'

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PetrologicalAccessories and I n s t r u m e n t s for Minera logy and Crystal- lography, including Ref rac tomete r s , Gonio-

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CONTENTS.

PAPERS READ. Page

7. Prof. J. E. Marr on the Pleistocene Deposits of the Lower Par t of the

Great Ouse Basin (Plate VII) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

8. Dr. W. D. Lang & Dr. L. F. Spath on the Black Marl of Black Ven and

Stonebarrow, in the Lias of the Dorset Coast (Plates VIII-XI) . . . . . . . . . . . . 144

9. Dr. Donald Parkinson on the Faunal Succession in the Carboniferous

Limestone and Bowland Shales at Clitheroe and Pendle Hill (Plates

XII-XVII) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

10. Mr. T. O. Morris & Prof. W. G. Fearnsides on the Stratigraphy and

Structure of the Cambrian Slate-Belt of l~antlle, Carnarvonshire

(Plates XVIII & XIX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

11. Dr. G. L. Elles on the Geological Structure of Ben Lawers and Meall

Corranaich, Perthshire (Plates XX & XXI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304

[The Editor of the Quarterly Journal is directed to make it known to the Pablie

that t h e A u t h o r s a l o n e a r e r e s p o n s i b l e f o r t h e f a c t s a n d o p i n i o n s

c o n t a i n e d in t h e i r r e s p e c t i v e P a p e r s , a n d f o r t h e c o r r e c t n e s s of

t h e i r r e f e r e n c e s . ]

A u t h o r s d e s i r o u s of c o m m u n i c a t i n g p a p e r s t o t h e S o c i e t y w i l l be

s u p p l i e d , on a p p l i c a t i o n t o t h e S e c r e t a r y , w i t h a c o p y of

' I n s t r u c t i o n s to A u t h o r s ' , i s s u e d by t h e C o u n c i l on ~he r e c o m -

m e n d a t i o n of t h e P u b l i c a t i o n C o m m i t t e e .

The Library at the Apartments of the Society ie open every Week Day from Ten

o'clock until Five, except on Saturdays (when the hours are from 10 to 1),

but will be closed from the afternoon of Saturday, July 24th, until the morning of l~Ionday, August 30th next.

- - T W

4 ,

mm Bl

|

V o l . L X X X I L No. 3,~7. I P~RT 8.

T H E

QUA RTERLY JOURNAL

O F T H B

GEOLOGICAL SOCIETY.

mDIT/BD BY

THE PERMAlqENT SECRETARY.

OCTOBER 19~h, 1926.

p i t h Eleven Plates, illustrating Papers by Dr. W. G. Woolnough & Sir T. W. Edgeworth David, Dr. T. W. Vaughan, Mr. H. P. Lewis, Dr. W. D. Lang, Mr.K.A. Davies, and Mr. R. M. 3ehu.~

LONDON :

LONGMANS, GREEN, & CO. LTD.

~s :--.CHARLES KLINCKSIECK, 11 RUB DE LILLE.

SOLD AI~O AT THR APARTMENTS OF THE SOCIETY.

LIST OF THE OFFICERS AND COUNCIL OF THE

GEOLOGICAL SOCIETY OF LONDON. Elected February 19th, 1926.

~rt~i~nt. Francis Arthur Bather, M.A., D.Sc., F.R.S.

~ic~--Drt~i~tnt~. John William Evans, C.B.E., D.Sc., Horace WoollastonMonekton, Treas.L.S.

LL.B., F.R.S. Sir Arthur Smith Woodward, LL.D., Sir Thomas Henry Holland, K.C.S.I., F.R.S., F.L.S.

K.C.I.E., D.Sc., F.R.S.

~ccr~taric~. Walter Campbell Smith, M.C., M.A. i James Archibald Douglas, M.A., D.Sc.

~or~i~a b~cretarl2. ~;r~a~ttrer. Prof. John Edward Marr, M.A., Sc.D., Robert Stansfield Herries, M.A.

F.E.S.

Francis ArthurBather, M.A., D.Sc.,F.R.S. Sir Thomas Henry Holland, K.C.S.I., Prof. Arthur Hubert Cox, D.Sc., Ph.D, Thomas Crook. Henry Dewey. James Archibald Douglas, M.A., D.Sc. Gertrude Lilian Elles, M.B.E., D.Sc. John William Evans, C.B.E., D.Sc., LL.B.,

F.R.S. Prof. William George Fearnsides, M.A. Prof. Edmund Johnston Garwood, M.A.,

Sc.D., F.R.S. Prof. William Thomas Gordon, M.A.,

D.Sc., F.R.S.E. Edward Greenly, D.Sc. Prof. Herbert Leader Hawkins, D.Sc. Robert Stansfield Herries, M.A.

K.C.I.E., D.Sc., F.R.S. Finlay Lorimer Kitchin, M.A., Sc.D. Prof. John Edward Marr, M.:k., Sc.D.,

F.R.S. Horace Woollaston Monckton, Treas.L.S. Tressilian Charles :Nicholas, O.B.E.,

M.C., M.A. John Pringle. Walter Campbell Smith, M.C., M.A. Leonard James Spencer, M.A., Sc.D.,

F.R.S. Arthur Elijah Trueman, D.Sc. Sir Arthur Smith Woodward, LL.D.,

F.R.S., F.L.S.

~mnanent ~tcr~tar~2. L. L. Belinfante, M.Sc.

~.tbrarian. Arthur Greig.

S T A N D I N G P U B L I C A T I O N COMMITTEE. Dr. F. A. Bather, President.

Mr.Dr. J.W'A.CampbellDouglas.Smith' } Secretaries. Mr. R. S. Herries, Treasurer.

Mr. T. Crook. Prof. J. E. Marr. Prof. W. W. Watts. Prof. W. G. Fearnsides. Mr. T. C. Nicholas. Sir Arthur Smith Wood- Prof. E. J. Garwood. Dr. L. J. Spencer. ward. Prof. H. L. Hawkins. Sir Aubrey Strahan.

O R D I N A R Y M E E T I N G S O F T H E G E O L O G I C A L S O C I E T Y TO BE HELD AT BURLINGTON HOUSE.

S~ssio~ 1926-1927. 1926.

Wednesday, November ... . . . . . . . . . . . . . . . . . . . . . . . . 3"--17* December ... . . . . . . . . . . . . . . . . . . . . . . . . 1 --15"

1927. Wednesday, January ... . . . . . . . . . . . . . . . . . . . . . . . . . . . 5~--19 *

,, February (Anniversary Meeting, Friday, February 18th) ......... 2*--23*

,, March .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 --23* ,, April . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6*--27 ,, May .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11"-- 25 ,, June . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15"

The asterisks denote the dates on which the Council will meet.

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C A R L Z E I S S ( L O N D O N ) L T D . W i n s l e y H o u s e , We l l s S t ree t , Oxfo rd S t ree t , L o n d o n , W . 1 .

CONTENTS.

Pages Proceedings of the Geological Society, Session 1925-26, including the

Anniversary Address of the President . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xlv-cxiv

PAPERS READ. Page

12. Dr. W. G. Woolnough & Sir ]:. W. Edgeworth David on Cretaceous Glaciation in Central Australia (Plates XXII & XXIII) . . . . . . . . . . . . . . . . . . . . 332

13. Dr. C. A. Matley on the Geology of the Cayman Islands (British West Indies), and their Relation to the Bartlett Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . 352

14. Dr. T. W. Vaughan on Species of Lepidocyc~ina and Carpenteria from the Cayman Islands, and their Geological Significance (Plates XXIV-XXVI) 388

15. Mr. L. 1~. Cox on Anthracopupa britannica sp. nov . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401

16. l~Ir. H. P. Lewis on Bo~opora undosa gen. et sp. nov. (Plates XXVII-XXIX) 411

17. Dr. W. D. Lamg on ~aos ragocla gen. nov. (Plate XXX) . . . . . . . . . . . . . . . . . . . . . . . . 428

18. l~Ir. K. A. Davies on the Geology of the Country between Drygarn and Abergwesyn, Breconshire (Plate XXXI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436

19. Mr. R. l~I. Jehu on the Geology of the District around Towyn and Aber- gynolwyn, l~Ierioneth (Plate XXXII) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465

[The Editor of the (~uarterly Journal is directed to make it known to the Pablio tha~ t h e A u t h o r s a l o n e a r e r e s p o n s i b l e f o r t h e f a c t s a n d o p i n i o n s c o n t a i n e d in t h e i r r e s p e c t i v e P a p e r s , a n d f o r t h e c o r r e c t n e s s of

t h e i r r e f e r e n c e s . ]

A u t h o r s d e s i r o u s of c o m m u n i c a t i n g p a p e r s to t h e S o c i e t y w i l l be s u p p l i e d , on a p p l i c a t i o n t o t h e S e c r e t a r y , w i t h a c o p y of ~ I n s t r u c ~ i o n s to A u t h o r s ' , i s s u e d b y t h e C o u n c i l on t h e r e c o m - m e n d a t i o n of t h e P u b l i c a t i o n C o m m i t t e e .

The Library at tJae Apar~nents of the Society is opfau every Week Day from Ten o'clock untfil Five, excep~ on Saturdays (whe~ the hours are from 10 to 1), except during the fortnight commencing on the first Monday in September, when the Library is closed for the purpose of cleaning.

I

Vol . L X X X I I . PART 4.

N o . 3 9 8 .

THE

QUA R T E R L Y .IOUItNA I,

OF THE

G E ( ) L O G I C A L SOCIETY.

E D I T E D B Y

THE PERMANENT SECRETARY.

DECEMBER 31St, 1926.

[With Seventeen Plates, illustrating Papers by Mr. J'. F. Jackson, Mrs. J. L~ngstaff, Prof. P. G. H. Boswell, Dr. J. Parkinson, and Dr. K. S. Sandford.]

LONDON :

LON(~MANS, GREEN, & CO. LTD.

]~ARIS:--CHARLES KLINCKBIECK, 1l RUE DE LILLE.

SOLD ALSO AT THE APARTMENTS OF THE SOCIETY.

Trice ~even 8Mllings and Sixpe~ce. j

I

LIST OI~ THE OFFICERS AND COUNCIL OF THE

GE()I OGICAL SOCIETY ()F L()ND()N. Elected February 19th, 1926.

~r~ ~i~tnt. Francis Arthur Bather, M.A., D.Sc., F.R.S.

John William Evans, C.B.E., D.Sc., Horace WoollastonMonckton, Treas.L.S. LL.B., F.R.S. Sir Arthur Smith Woodward, LL.D.,

Sir Thomas Henry Holland, K.C.S.L, F.R.S., F.L.S. K.C.I.E., D.Sc., F.R.S.

~cr~tarit~. Walter 0amphell Smith, M.0., M.A. [ James Archibald Douglas, M.A., D.Sc.

~0mgn ~cmarl). ~;rta~ur~r. Prof. John Edward Mart, M.A~, Sc.D., Robert Stansfield Herries, M.A.

F.I~.S.

Francis Arthur Bather, ~¢[.A., D.Sc.,F.I~.S Sir Thomas Henry Holland, K.C.S.I., Prof. Arthur Hubert Cox, D.Sc., Ph .D Thomas Crook. Henry Dewey. James Archibald Douglas, M.A., D.Se. Gertrude Lilian Elles, M.B.E., D.Sc. John William Evans, C.B.E., D.Sc, LL.B.,

F.I~.S. Prof. William George Fearnsides, ]V[.A. Prof. Edmund Johnston Garwood, M.A.,

Sc.D., F.R.S. Prof. William Thomas Gordon, M.A.,

D.Sc., F.R.S.E. Edward Greenly, D.Sc. Prof Herbert Leader Hawkins, D.Sc. Robert Stansfield Herries, M.A.

K.C.I.E., D.Sc., F.R.S. Finlay Lorimer Kitchin, M.A., Sc.D. Prof. John Edward Marr, M.A., Sc.D.,

F.I~.S. Horace Woollaston Monckton, Treas.L.S. Tressilian Charles Nicholas, O.B.E.,

M.C., M.A. John Pringle. Walter Campbell Smith, M.C., M.A. Leonard James Spencer, M.A., Sc.D.,

F.R.S. Arthur Elijah Trueman, D.Sc. Sir Arthur Smith Woodward, LL.D.,

F. ILS., F.L,S.

p t r m a n e n t ~ccr t t ay l2 . L. L. Belinfante, M.Se.

~£ibrar ian. Arthur Greig.

S T A N D I N G P U B L I C A T I O N C O M M I T T E E . Dr. F. A. Bather, President.

Mr. W. Campbell Smith. ) Secretaries. Mr. R. S. Herries, Treasurer. Dr. J. A. Douglas.

Mr. T. Crook. Prof. J. E. Marr. Prof. W. W. Watts . Prof. W. G. Fearnsides. Mr. T. C. Nicholas. Sir Arthur Smith Wood- Prof. E. J. Garwood. Dr. L. J. Spencer. ward. Prof. H. L. Hawkins. Sir Aubrey Strahan.

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SEss Io~ 1 9 2 6 - 1 9 2 7 .

1927. Wednesday, January . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5v--19 v

,, February (Anniversary Meeting, Friday, February 18th) ......... 2~--23 ~

,, March . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - -23 v ,, April . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6~--27 ,, May . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 ~ - 25

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SWIFT & SON LTD. kers of the Highest Grade

EOPE8 & AOOE880RIES s to all Scie~tific .Departments of

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" U N I V E R S A L T E C H N I C A L " M I C R O S C O P E Perfectly adapted for the most ex. acting investigations in PETROLOGY, MI~ERALOOY, CRYBTALLOGRAPH Y~ etc., while the addition ~f a special vertical illuminator wflh self- contained electric lamp allows of it~ bein,~ u~ed for the examination of Metals and other Opaque Bodies.

Desoripti~,e circular seM o~ request

UNIVERSITY OPTICAL WORKS :

81 TOTTENHAM COURT RD., LONDON W.I

E I S CRYSTAL GONIOMETER AND SPECTROMETER

Adapted for the observation of sm~ll and defective crystal faces.

This instrument takes the form of a DOUBLE CIRCLE CRYSTXL GONIOMETER, readily convertible into a SINGLE CIRCLE GONIO-

METER and SPECTROMETER.

See detailed description by C. Pulfrich in Winkelmanns' Hand- buch der Physik, 2nd edition, volume vi., 1906, p. 58~.

THE ABBE-PIJLFRICH CRYSTAL REFRACTOMETER utilises the total reflection method, and enables the p r i nc ipa l refractive indices and principal planes of the crystal to be deter-

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F~d~ particulars of Zeiss Opticat Equipment for Mi~eralogica~ Observations in Booktet 101/449 sent, on request, by the

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PAPEI~S %EAD. Page

20. Mr. J. F. Jackson on the Junction-Bed of the Middle and Upper Lias on the Dorset Coast (Plates XXXIII & XXXIV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 490

21. Mrs. J. Longstaff : a Revision of the British Carboniferous Murchisoniidm (Plates XXXV-XXXV[I) .... . . . : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 526

22. Prof. P. G. H Boswell on tha Geology of the Eastern Part of the Denbigh- shire Moors (Plates XXXVIII & XXXIX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556

23. Mr. V. G. Glenday & Dr. J. Parkinson on the Geology of the Suk Hills, Kenya Colony (Plates XL-XLIV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 586

2L Dr. K. S. Sand~ord on the Geology of North-East L'md, Spitsbergen (Plates XLV-XLIX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 615

ETITLE-PAGE, CONTEN'rS, and INDEX tO VOL. LXXXII.]

[The Editor of the Quarterly Journal is directed to make it known to the Public that t h e A u t h o r s a l o n e a r e r e s p o n s i b l e fo r t h e f a c t s a n d o p i n i o n s e o n t a i n e d in t h e i r r e s p e c t i v e P a p e r s , a n d f o r t h e c o r r e c t n e s s of

t h e i r r e f e r e n c e s . ]

A u t h o r s d e s i r o u s of c o m m u n i c a t i n g p a p e r s to t h e S o c i e t y w i l l be s u p p l i e d , on a p p l i c a t i o n to t h e S e c r e t a r y , w i t h a c o p y of

' I n s t r u c t i o n s to A u t h o r s ' , i s s u e d by t h e C o u n c i l on t h e r e c o m - m e n d a t i o n of t h e P u b l i c a t i o n C o m m i t t e e .

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), except during the fortnight commencing on the first Monday in September, when the Library is closed for the purpose of cleaning.