THE

QUARTERLY JOURNAL

OF TIlE

GEOLOGICAL SOCIETY OF LONDON.

EDITED BY

THE PERMANENT SECRETARY OF THE GEOLOGICAL SOCIETY.

Quod si cui mor~alium cordi e t curm sit n o a t a n t u m inveat is h~erere, a tque iis uti, sed ad. u l t e r io ra pene t ra t e ; a tque noa d isputando adversar ium, sed opere n a t u r a m viucere denique noa belle et p robab i l i t e r opinur/, sed certo et ostensive s~ire ; tales, t a n q u a m veri s~iea t iarum fllii, nobis (si v idebi tur ) se ad jungan t --Z~ovu.t Organum, Pr~fatio.

V O L U M E T H E E I G H T Y - S E C O N D ,

FOR 1926.

LONDON :

LONGMANS, GREEN, AND CO. P A R I S : C H A R L E S K L I N C K S I E C K , 11 R U E D E LILLE.

SOLD ALSO A T T H E A P A R T M E N T S OF T H E S O C I E T Y ,

MCMXXVI,

OF THE

O F F I C E . R 8 OF FHB

(.;I,:OLOGICAL SOCIETY OF I,OND()N. Elected February 19th, 1926.

I~rt~i~tnt. Fram'.is Arthur Bather, M.A., D.So., F.R.S.

~itt,~rtai~tnt~. John William Evans, C.B.E., D.Sc., [ Horaee Wooliaston Monekton, Treas.L.S.

LL.B., F.R.S. I 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.

~t tr t tar i t~ . Walter Campbell Smith, M.C., M.A. ', James Archibald Douglas, M.&., D.Se.

~ortign ~ttrttarp. ~rta~urtr. Prof. John Edward Mart, M.A., Sc.D., ] Robert. Stansfield Iterries, M.A.

F.R.S. l

Francis Arthur Bather, M. A.. D.Sc.,F.R,S. Pz.of. Arthur Hubert Cox, 1).Sc., Ph.D. Thomas Crook. Henry Dewey. James Archibald Douglas. M.A., D.Sc. Gertrude Lilian EUes, M.B.E., D.Sc. John William Evans, C.B.E., D.Se., LL.B.,

F.R.S. Prof. Wi!liam George Fearnsides, M.A. Prof. Edmund Johnston Garwood, M.A.,

S,..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.

Sir Thomas Henry Holland, K.C.S.I., 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.R.S. Horace Woollaston Monektou, Treas.L.S. T~essilian 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.

~mnantnt ~ttrttarv. L. L. Belinfant*, M.Sc.

Kibrarian Arthur Oreig.

STANDING PUBLICATION COMMITTEE. Dr. F. A. Bather, President.

Mr. W. Campbell Smith. } Secretaries. Mr. R. S. Herries, Treasurar. Dr. J. A. Douglas.

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

TABI~E OF C()NTENTS.

]3OSWELL, PERCY GEORGE HAI~INALL. A Contribution to the Geology of the Eastern Part of the Denbighshire Moors (Plates~XXXVIII & XXXIX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556

Cox, LESLIE R~GINALD. Notes on the I, amellibranchia [from the Black Marl of Black Ven and StonebarrowJ : . . . . . . . . . . . . . . . 180

. . . . . . A n t h r a c o p u p a b r i t a n n i c a sp. nov., a Land Gastropod from the Red Beds of the Uppermost Coal Measures of Northern Worcestershire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401

DAVID, Sir T. W. EDGEWORTH (& W. G. WOOLNOUGH). Creta- ceous Glaciation in Central Australia (Plates XXII & XXIII) . 332

DAVIES~ KENNETH ARTHUR. The Geology of the Country between Drygarn and Abergwesyn. Breconshire (Plate XXXI) . . . . . . . . 436

DINGWALL, JANET MITCHELL MARR. On Cyathocl i s{a , a New Genus ot Carboniferous Coral (Plates I -HI) . . . . . . . . . . . . . . . . 12

EDWARDS, WILFRED NOnMAN. :Fossil Plants from the Nubian Sandstone of Eastern Darfur . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

ELLES, GERTRUDE LILIAN. The Geological Structure of Ben Lawers and Meall Corra. aich, Perthshire (Plates XX & XXI). 804

FEAI~NS1DES, WILLIAM GEORGE. Stratigraphical Note [on the Garth Grit] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423

-(& T. 0. MORRIS). The Stratigraphy and Structure of the Cambrian Slate-Belt of Nantlle, Carnarvonshire (Plates XVIII & XIX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

~LENDAY, VINCENT G. (~ J. PARKINSON). The Geology of the Suk Hills, Kenya Colony (Plates XL-XLIV) . . . . . . . . . . . . . . 586

JACKSON, JAMES FREDERICK. The Junction-Bed of the Middle and Upper Lias on the Dorset Coast (Plates XXXIII & XXXIV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 490

JE~U, RALPH MAURICE. The Geology or" the Dislrict around Towyn and Abergynolwyn, Merioneth (Plate XXXII) . . . . . . 465

KENNA:RD, ALFRED SANTER (& B. n. WOODWARD). Report on the Non-Marine Mollusca [from the Pleistocene Deposits of the Lower Part of the Great Ouse Basin~ . . . . . . . . . . . . . . . . . . 139

a 2

iv TABLE OF CONTEI~TS. Page

LAN~, ~VILLIA~ DXCKSON. ~'aos pagoda (Salter), the Type of a New Genus of Silurian Corals (Plate XXX) . . . . . . . . . . . . . . . . 4"-)8

(& L. F. SPATH). The Black Marl of Black Veil and Stone- barrow in the Lias of the Dorset Coast (Plates VIII-XI) . . . . 144

LEWIS, HERBERT I)ItICE. On Bolopora undosa gen. et sp. nov. : a Rock-building Brvozoan with Phosphatized Skeleton, from the Basal Arenig llocks of Ffestiniog, North Wales (Plates XXVII-XXIX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411

LONGSTAFF, JANE. A 1,)evisi,)ll or" the British Carboniferous Murchisoniidm, with Notes ou their Distribution alJd Descrip- tions of some New Species (Plates XXXV-XXXVII) . . . . . . . . 526

MARR, JOHN EDWAr~D. The Pleistocene Deposits of the Lower Part of the Great Ouse Basin (Plate VII) . . . . . . . . . . . . . . . . . . 101

MATLEY, CttArtLF.S ALFI~.ED. The Geology of the Cayman Islands (British West Indies), and their Relation to the Bartlett Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352

MORRIS, THOMAS OWEN (& "~V. G. FEARNSIDES). The Strnti- graphy and Structure of the Cambrian Slate-Belt of Nantlle, Carnarvonshire (Plates XVII[ & XIX) . . . . . . . . . . . . . . . . . . . . 250

I~UIR-~VOOD, HELEN MARGUERITE. Notes on the Brachiopoda [from the Black Marl of Black Ven and Stonebarrowj . . . . . . . . 184

~ . Description of a New Species of Spindler and of one of Retic~daria fi'om the Lower Carboniferous near Clitheroe (Plate XVI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

NUTTALL, WINFRED LAURENCE FaLKINER. A Revision of the Orbitoides of Christmas Island, Indian Ocean (Plates IV & V). 22

OLI)HAM, RIC~XRD DIXON. The Depth of Origin of Earthquakes. 67

PAmClNSON, DONALD. The Faunal Suece.,-ion in the Carboniferc, us Limestone and Bowland Shales at Clitheroe ~,nd Pendle ttill. Lancashire (Plates XII-XVII) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

PARKINSON, JOHN (,~: V. G. GLENDAY). The Geology of the Suk Hills, Kenya Colony (Plates XL-XLIV) . . . . . . . . . . . . . . . . . . 586

SANDFOaD, K~..nNETH STUAnT. The Geology of North-E~Lst Land, Spitsbergen (Plates XLV-XLIX) . . . . . . . . . . . . . . . . . . . . . . . . 615

SI~ITH, WALTEIr CAMPI~ELL. The Volcanic Rocks of Christmas Island, Indian Ocean (Plate VI) . . . . . . . . . . . . . . . . . . . . . . . . . . 44

SOLI, AS, WILT.IA~ JOHNSOn. On a Sagittal Section of the Skull o f Australopithecus africa~us . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I

SPATH, L. F. Notes on some New or Incompletely-known Ammonites Ffro~J the Black Marl of Black Ven and Stone- barrow] (Plates IX-XI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

TRUEM~.I% ARTHUIt ELIJAH (& D. M. WILLIA?*IS). Note on certain Echioceratidee [from the Black 3Jar! of Black Ven and Stone- barrow] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

TABLE OF CONTENTS. V

_Page

YAUGHAN, THO~IAS WAYLAND. Species of Zepidocyclina and Carpenteria frnm the Caymaa Islands, and their Geological Significance (Plates X X I V - X X V I ) . . . . . . . . . . . . . . . . . . . . . . . . 388

Wn,I.IA~S, DAISY MARY (& A. E. TRUe,AN). Note on certain Echioceratidm [from the Black Marl of Black Ven and Stone- barrow] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

WOODWARD, BERNARD BARHA~t (& A. S. KENNAnD). Report on the Non-Marine Mollusca [from the Pleistocene Deposits of the Lower Par t of the Great Ouse Basin] . . . . . . . . . . . . . . . . . . . . . . 139

WOOLNOUGH, WALTER G. (& Sir T. W. EDGEWORTH DAVID). Cretaceous Glaciation in Central Australia (Plates X X I I & X X I I I ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332

PROCEEDINGS.

Proceedings of the Meetings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i, ciii

Annual Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii

Lists of Donnrs to the Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xili

List of Donors to the Voluntary Public.-.tion Fund . . . . . . . . . . . . xix

List of Foreign Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiv

List of Foreign Correspondents . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxv

List of Wollaston Medallists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxvi

List of Murchisoa Medallists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxvii

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 . . . . . . . . . . . . . . . x

Anniversary Address of the President . . . . . . . . . . . . . . . . . . . . . . . . xlv

DAVID, Sir T. W. EDGEWORTH. On Salient Features in the Stratigraphy, Tectonic Structure, and Physio~'aphy of the Commonwealth of Australia . . . . . . . . . . . . . . . . . . . . . . . . . . . .

NOPCSA, Baron FRANZ. On Deuterosaurus biarmicus Eichwa ld . .

CV

cii

Vi TABLE OF CONTENTS. Page

ODELL, NOEL EWART. On Supposed Fossils from the Northern Face of Mount Everest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . cv

OSBORN, HE~rRY FAIZtFI~LD. On the Methods and Results of the American Museum Expedition in the Gobi Desert . . . . . . cx

S:KAND, S. JAMES. On the Alkaline Rocks and Ring-Intrusions of Pilansberg (Transvaal) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

~rHITE, ERROL IVOR. On Bothriolepi.s canadensis Whit~aves . . iv

LIST OF T H E F O S S I L S F I G U R E D A N D D E S C R I B E D

I N T H I S V O L U M E .

Name of Species. Fo rma t ion . Locali ty. Page

Carpenteria amerivana, pl. xxvi, fig. 4 . . . . . . . . . . . . . . .

Discocyclina oceanica sp. nov., figs. 2 -3 & pl. v, fig. 9 . . . . . .

Lepidocyclina ephippoides, pl. v, figs. 1, 2, 3, 8, & 10...

- - gigas, pi. xxv, figs. i a & { l b . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

sp. of. marginata, pl. xxvi, figs. 1 & 2 . . . . . . . . .

yurnagunensis, pl. xxv, E figs. 2 -6 . . . . . . . . . . . . . . . . . . . . . . . . f

sp. indet , pl. xxvi, fig. 3 [_ L. (Eulepidina) andrewsiana, (

pl. iv, figs. 1-4 . . . . . . . . . . . . . . . - - ( ~ ) chapmani sp. nov.,

pl. iv, figs. 7 -9 . . . . . . . . . . . . . . . - - (----) feffmosa .~ - - ( ) in~equalis, pl. iv, I

fig. 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . i ( ~ ) insulw-natalis, pl.iv, ]

figs. 2, 5, & 6 . . . . . . . . . . . . . . . . . . L. (Nephrolepidina) undosa. ]

pl. xxiv, figs. 1 & 2 . . . . . . . . . ( - - - ) ~ vat. tumida

nov., pl. xxiv, figs. 3 -5 ... Miog~/psina neodispansa, pl. v,i

fig. 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . L Spiroclypeus 91obulus, fig. 1 &i |

pl. v, figs. 5 -7 . . . . . . . . . . . . . . . i J

FORA $1 I N I F E R A .

Miocene . . . . . . . .

Oligoeene ... . . . . C a y m a n Brae . . . I 399

MioceneE~ . . . . . . . . . . . . . . ... i 1 Christmasisland . . . . . . . . . il it 38-4034_36

(" [ 1396-98

Oligocene . . . . . . .{ C a y m a n Brac...!-{ 398-99

i I ~ I - 9 3 ( (. 399 f

i 27-29

Christll~as 31-32 Is land . . . . . . . . . i 29-30

C a y m a n Brae. . .

i

Oligocene . . . . . . i

f i

Miocene . . . . . . .

I Chr i s tmas

I s l and . . . . . . . . .

33--34

( 30-31

"37-38

36-37

Careinophyllum s p , pl. xiii, figs. 2 a - 2 d . . . . . . . . . . . . . . . . . .

Chonophyllum patellatum, I pl. xxx, figs. 4 -6 . . . . . . . . . . . . !

Clisiophyllum sp., pl. xiii, figs. I a - I c . . . . . . . . . . . . . . . . . .

Cyathoclisia tabernavulum gen. et sp. nov., pls. i - i i i . . .

Cyathophyllum (Palwosmilia) murchismd ear. pendlense nov., pl. xii, figs. 2 a & 2 b.

Koni~ckophyllum clitheroense sp. n o v , pl. xii, figs. 1 a -19

M~wophyllum crateroides pl. xxx, figs. 7 & 8 . . . . . . . . :

Naospagoda gen. nov., figs. 1-2 & pl. xxx . . . . . . . . . . . . . . . . . . . . .

A C T I N O Z O A ,

Carboniferous Limes tone ...

W e n l o c k . . . . . . . . .

~a rbou i f e rous L imes tone ...

)

Si lur ian . . . . . . . . .

S i lur ian . . . . . . . . .

Cl i theroe dis t r ic t . . . . . . . .

Go t land . . . . . . . Cl i theroe

dis t r ic t . . . . . . B u r r i n g t o n

Combe . . . . . . . . .

Cl i theroe dis t r ic t . . . . . .

Cl i theroe dis t r ic t . . . . . .

New South Wales . . . . . . . .

Arct ic Amer i ca

230-31

432

229

12-21

231

229-30

430

428--35

VIII FOSglL8 FIeURED AND DE$CRIBED.

l~'ame of Speeies. j F o r m a t i o n . [ Local i ty . i Page

CIglNOIDEA.

? Isoerinu, sp., fig. 2 . . . . . . . . . . . . I ? 0 r e t a e e o u s ---I Sou th h u s t r a l i a j 337, 338

BRYOZOA.

JBoloFora undosa gen. et sp.r j [ nov., figs. 1-7 & pls. xxvii-; xxix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I Aren ig . . . . . . . . . . . . F fes t in iog . . . . . . 411-27

~RACHIOPODA.

JBraeh!lthyris spp . . . . . . . . . . . . . . . . "~ _Productu~ h u m e r o ~ . . . . . . . . . I _Pugnax acuminatus, pl. xiv, I

figs. 3 e & 3 f . . . . . . . . . . . . . . . . . . J - - - - - var.plieatm% pl. xiv, figs. 3 a - 3 d . . . . . . . . . . . . . . . . . .

- . m e , genus, pl. xiv, f igs .

l a - l r . . . . . . . . . . . . . . . . . . . . . . . . ~ i su/catus, pl. xiv, figs. 2 a -

2 d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ca rbon i fe rous var. ~ 2 y / o b ~ , i ? L i m e s t o n e ..

pupsPl, xiv, fig. 4 . . . . . . . . . . . . . . . . . . ! I ttda nodopustulosa sp.' I

nov., fig. 3 & pl. xv, figs. 2 a - I

2b . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I t letieularia lobata sp. nov., I

pl. xvi, fgs . l a - l e & 2 ... J Etririfer bollandenais sp. nov., [

pl. xvi, figs. 3, 4 a, & 4 b ... I coplowensi, sp. nov., pl. xv, figs. 1 a -1 e . . . . . . . . . )

Cl i theroe Dis t r ic t . . . . . . .

i ' 233 233

236-37

: 2 3 8 - 3 9 i

237-38

238

i 231-33

242 -44

241-42

( 2 3 3 - ~

LA~IELLIBRANCHIATA.

Chlamys (Camptoneetes ?) of. I ~ [ lohbergensis . . . . . . . . . . . . . . . . . . I[

Gervillia lanceolata . . . . . . . . . . . . [ | .~. Inoeeram~s dorsetensis sp . I . ~ z a s . . . . . . . . . . . . . . .

nov. , fig. 5 . . . . . . . . . . . . . . . . . . . . . j I . faberi, fig. 4 . . . . . . . . . . . . . . . l )

r( i 180-81

Dorse t Coast r~ 181

I 183-84 , t, 181-83

(~'ASTROPODA,

Aclisoides ( / ) armstronffiana ...} Carboni fe rous . . . - . . . . . . . . . . . . . . . ri )

�9 . . . . . . . . . . . . . . . . . . . . . . ,

Anthracopupa britaunica sp.~ nov. , figs. 1 a-2b Coal Measures . . : C len t Hi l l . . . . . . ! 401 -10

Cal iendrumvi t ta tum . . . . . . . . . . . . ] Bol land . . . . . . . . . 1 539 T o d m o r d e n . . . . . . I 538 Cerithioides (?) oweni . . . . . . . . . . . ~ Carboni fe rous . . . Var ious . . . . . . . . . 537

- - teleseopium . . . . . . . . . . . . . . . . . . - (?) tuedia . . . . . . . . . . . . . . . . . . ) Lewis B u r n . . . . . . 538

POSSIL8 F I G U R E D AND D I ~ O R I B E D . i x

N a m e of Species. Format ion . I Local i ty . i P a g e

G.tS~'ROPOD.~ (continued).

t - lypergmda acuminata , pl. ''~ xxxvi, fig. 1 . . . . . . . . . . . . . . . . . .

acutiearina~a sp. nov., i pl. xxxvii, figs. I a-1 c & 2 . .

benniana sp. nov., pl. xxxvi, figs. 3 - 5 . . . . . . . . . . . . . . .

cincta, pl. xxxvi, fig. 2 ... compacta, pl. xxxv, fig.

11 . . . . . . . . .. . . . . . . . .. . . . . . . . . . . . . . conula, pl. xxxvii, figs. 3

& 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . deplanata, pl. xxxvi, fig.

15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . elongata . . . . . . . . . . . . . . . . . . . . .

- - f r a g i l i s nora. nov., p l . xxxvii, figs. 6 -8 . . . . . . . . . . . . . . .

graciliz, pl. xxxvii, figs.:

- - "(i~) hormophera sp. nov., 9 -1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

pl. xxxv, figs. 7 - 9 b . . . . . . . . . , kirkb.r pl. xxxvi, fig. 9 . . m'coyi . . . . . . . . . . . . . . . . . . . . . . .

- - - - ~ a T l a . . . . . . . . . . . . . . . . . . . . . . , .

peutonensis . . . . . . . . . . . . . . . . . i (?) percar ina ta sp. nov.,i

pl. xxxvi, figs. 10 & 11 . . . . . . t p lana , pl. xxxvii, figs. 5 a!

b & 5 b . . . . . . . . . . . . . . . . . . . . . . . . . . . --. (?) p y g m w a , pl. xxxvi. figs. 1 2 a & 125 . . . . . . . . . . . . . . . I

quadricarinata, pl. xxxv,! fig, 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . .

qui~quecarinata, pl. xxxv, fig. 12 . . . . . . . . . . . . . . . . . . . . . . . . . . .

- - r a ~ d e r s l o n e n s i s sp. nov., pl. xxxvi, figs. 6 -8 . . . . . . . . . . . .

thomsoni, pl. xxxvi, figs. 1 3 a , 1 3 b , & 14 . . . . . . . . . . . . . .

- - turr icu la ta . . . . . . . . . . . . . . . . . - - variabilis . . . . . . . . . . . . . . . . . . - - you~giana, pl. xxxvii,

figs. 14 & 15 . . . . . . . . . . . . . . . . . ~ u r c h i s o n i a archiaciana, pl.

xxxv, figs. 1 a & 1 b . . . . . . . . . dispar . . . . . . . . . . . . . . . . . . . . . . . . f imbricari~mta . . . . . . . . . . . .

- - - - - - vat . denensis nov. pl. xxxv, fig. 2 . . . . . . . . . . . . . .

f i ~ i f o r m i s . . . . . . .

{ i lbertsoni . . . . . . . . . . . . . . . . . . ibernica . . . . . . . . . . . . . . . . . i

kendalens is . . . . . . . . . . . . . . . ] marr i , pl. xxxv, fig. 3 ...I

- - p y r a m i d a t a . . . . . . . . . . . . . . . ] scotica . . . . . . . . . . . . . . . . . . . . . smighiana . . . . . . . . . . . . . . . . . . )

Camps ie . . . . . . . . . 540-41

Ki lb i rn ie . . . . . . . . . 5 4 1 - 4 2 Bande ra tone

Cast le . . . . . . . . . 542 Da i ry . . . . . . . . . . . . 542

Scot land . . . . . . . . . 543

Ba l ladoo le . . . . . . 543-44

Scot land . . . . . . . . . 544 D r a p e r s t o w n ... 544

Da i ry . . . . . . . . . . . . { 544 4 5 L-

5 4 5 - 4 6 Var ious . . . . . . . . .

/

i 5 4 7 1 5 4 8

/

Var ious . . . . . . . . . ~ 548 -49

Enniski l len . . . . . . 5 4 9 - 5 0

Var ious . . . . . . . . . I 550-51 R a n d e r s t o n e I

Cast le . . . . . . . . . ' 551

550 i Yar ious [ 551-52

. . . . . . . . . ~ 552 l

) ~ 5 5 2 - 5 3

Arb ig land . . . . . . 5 2 9 - 3 0 } V a r i o u s ( 580-31

. . . . . . . . . 531

Da i ry . . . . . . . . . . . . 5 3 1 - 3 2 f 5 a 2

J 532 Var ious . . . . . . . . . | 532

( 533 S h a p Tol l -Bar . . i 533 Bol land . . . . . . . . . l 534 D a l r y . . . . . . . . . . . . 534 St i r l ing . . . . . . . . . 1 5 3 4 - 3 5

Carboni ferous . . .

F O S S I L S F I G U R E D A N D D E S C R I B E D .

5Tame of Species. ] 1 i I F o r m a t i o n . I Local i ty . P a g e

C4ASTaOPODA (contiuued).

Marchisonia subtilislrhda . . . . . . ~ ,Ayrshire . . . . . . . . . I 535 tatei I Howick . . . . . . . . . I 535

i

! W a r k . . . . . . . . . . . . ] 536 temdssima . . . . . . . . . . . . . . . . . . verneuiliana . . . . . . . . . . . . . . . [ Var ious . . . . . . . . I 536 ,o~atct . . . . . . . . . . . . . . . . . . . . ~-Carboniferotts. . . Na r rowda le . . . . . . [ 536

Pithodeaampli~sima. (?) melauoides, . . . . . . . . . . . . pl. xxxv, I Various . . . . . . . . . t 5 3 9

figs. 5 & 6 . . . . . . . . . . . . . . . . . . . . . Var ious . . . . . . . . . [ 53,q 40 percincta . . . . . . . . . . . . . . . . . . J Der ry lo ran . . . . . I 539

Arietites costariformis sp. nov., pl. x, fig. 2 . . . . . . . . . . . . . .

- ~ obtus~formis sp. nov.. pl. xi, fig. 4 . . . . . . . . . . . . . . . . . .

preplotti sp. nov., pl. xi, fig. 7 . . . . . . . . . . . . . . . . . . . . . . . . . . .

subturneri sp. nov., pl. x, fig. 2 . . . . . . . . . . . . . . . . . . . . . . . . . . .

Asteroceras mar~aritoides. pl . ix, figs. 8 a - 8 o & pl . x, f i~ . 5 a - S e . . . . . . . . . . . . . . . . . . . . . ; .... stellare, pl. x, fig. 9 . . . . . . ,

Crucilobiceras orm~tilobatum, pl. xi, figs. I a & 1 b . . . . . . . . .

Cymbites neg. lectus nora. nov.. pl. ix, fig. l 0 . . . . . . . . . . . . . . . . . .

- - s u b c o s t d a t u s sp. nov., ul . xi, fig. 3 . . . . . . . . . . . . . . . . . .

Deroeeras euseulptum sp. nov., pl. x, fig. 3 . . . . . . . . . . . . . . . . . . . .

obesum, fig, 2 . . . . . . . . . . . . Eoderoceras bispinifferum,

pl. xi, figs. 6 a & 6 b . . . . . . . . . proximara, pi. xi, figs. 2 a

& 2 b . . . . . . . . . . . . . . . . . . . . . . . . . . . rhomboidale sp. nov.,

pl. xi, fig. 5 . . . . . . . . . . . . . . . . . . Leptonotoceras (?) app. ind .... Microderoceras inexpec~ans,

sp. nov., pl. x, figs. 6 a & 6 b Oxynoticeras 13/mense . . . . . . . . .

-~ wingravei . . . . . . . . . . . . . . . . . _Promieroceras capricornoides,

pl. ix, fig. 3 . . . . . . . . . . . . . . . . . . marstonense, pl. x, fig. 4 perplanie.osta, pl. ix,

figs. 2 a & 2b . . . . . . . . . . . . . . . . . . - Tlanicosta, pl. ix, figs.

1 a - l b , & 7 a - 7 b . . . . . . . . . . . . precompressum sp. nov.,

pl. ix, figs. 5 a & 5 b . . . . . . . . . pyritosum, pl. ix, figs. 4 a-

4 c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

~'ipheroceras dudressieri, pl. ix. fig. 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . I

AMMONOIDEA.

L i a s . . . . . . . . . . . . . . .

l Dorse t Coas t ... {

( i 166-67

i 167-68

167

i 166 i I 168-69

169

176-77

1 6 9 - 1 7 0

170

175-76 174- 75

173

173 -74

174 177

171 170-71 170

1 7 2 - 7 3 179

172

171-72

173

172

172

FOSSILS FIGURED AND DESCRIBED. xi

Name of Species. I F~)rmation. j Locality. I Page

ANTII ROPOMORPIIID~g.

Australopithecus a fricanus, figs. 1-11 ..................... ?

~ I LICALES,

Weichselia ~eticulata, figs. I :Nubian Sand- & 2 ' stone .........

CONIFERALES.

Dadoxylon ~gyptiacum, figs. 5 -I ] & 6 ................ Nubian Sand-

Frenelopsis hohene'gg'eri:'fig's: 3 [ stone . . . . . . . . . & 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , j

South Africa ...[ 1-11

Eastern Darfurl 9t-95

Eastern Darfur

EXPLANATION O F THE PLATES.

PLATES

I - I I I f CvarHocL~sIa ra2~s i l lustrat ing Miss J. M. |

M. Dingwall 's paper on a New Genus of' Carbo- ~. , niferous Coral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . )

IV&V

PLATE

VI

PAGe.

12

{ LEPIDOCI'CLINA, 8PIROCLITs AND .DIscOCYCIdNJ, } i l lustrat ing Mr. W. L. F. Nuttal l 's revision or" the 22 Orbitoides of Christmas Island . . . . . . . . . . . . . . . . . . . . . . . . . . .

BASALTS FROM CIIRISTMAS ISLA,~D, illustrating Mr. W. ] Campbell Smith 's paper oa the Volcanic Rocks of ~ 44 that island . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . a !

MAP OF THe: Low~:R PART OF TIIE GRZAT Oust: BASI~, V I I i l lustrating Prof'. J . E. Mar t ' s paper on the Pleisto-

cene Deposits of that area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ) I01

f THE FLATSTONE8, and a STELLA.K[8 ~ODULE IN PLACE,] V I I I i l lustrat ing Dr. W. D. Lang's paper on the Black f 144

Marl of Black Ven and Stonebarrow . . . . . . . . . . . . . . . . . . PLAYES

( PRo~zc~oc~Ras, X~OCERaS, .4ST~ROCE~S AND CrX- | mrr~s; ARIETlrES, D~OC~as AND ~lleaoD~oe~zas; |

I X - X I ~ and CRUCrLOBZCE2CaS ASD EODEROCEP.aS, i l lustrating ~. 165 I Dr. L. F. Spath's paper on New or Incomplete ly- I (. known Ammonites from the above-mentioned a rea . )

f KOXlNCKOP2fYLL~'M AND PAL~7~OSMILIa; CLISlOPHYLL~r.~I AND CXRCINOPHYLLUM ; PUG.VAX ; SPIRIFER AND t PUSTULA ; 2Z~ETIOULARIA AND ~PIRIFER : and GEOLO- I

XlI-XVlI~ oICAL MAP OF THE CLITtIEROE AND PENDLE-HILL ~ 188 ] DISTRICT, illustrating Dr. Donald Parkinson's paper I ] on the Faunal Succession in the Carboniferous] ( Limestone and Bowland Shales of that area . . . . . . . . . )

GEOLOGICAL MAP OF TIlE CAMBRIAN SLATE-BELT OP ~ANTLLE; and SERIAL SECTIONS across the same, ["

X V I I I & X I X ~ il lustrating the paper by Mr. T. O. Morris and ! Prof. W. G. Fearnsides on the Strat igraphy and I

Structure of that slate-belt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . )

250

EXPLANATION OF THE PLATES. ..o

Xlll

PLATES PAGE

(GEOLOGICAL INDEX-.-~]AP OF PART OF TIIE BEN~ [ LAWER8 RANGE: and ~IAI' 8tIOWlNG TIIE 8TRUC- ] J TURE OV TIIS BEN LAWEtlS N^PP~, illustrating XX & XXI 304: Miss G. L. Elles's p~tper on the Geological f

I S~ru~turo or" Zell L w e r s ana Mea~l Co~r~-I

I naich . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . )

(~[AP SIIOWING CRETACEOUF ERRA'rICS ; and SECTION i PROM NEAR ~IOUNT BABBAGE TO LAKE CALLA-!

X X I I & X X I I I ~ nONNA, i l lustrat i ,g the paper by Dr. W. G. ~ 332 [ Woolnough & Sit' T. W. Edgeworth David on I

Cretaceous Glaciation in Central Australia ... )

XXlV-XXVI

(LEPIDOCYCLLYA [WDOSA AND L. UNDOSA VAR. TUMIDA; LEPIDOC:FCLIXA GIGAS AND L. YURNA- ] GUA'ENSIS; and LE~9OCrCZLVA spp. AND CaR- ~, e~.vrEnra AJLERICA.VA, i l lustrating Dr. T. W~Ly- ! laud Vaughan's paper on those fossils.... . . . . . . . . . )

388

X X V I I - X X I X Bozo~o~a ~:~'DOSa G~N. ET SP. NOV., illustrating'[ 411 Mr. H. P. Lewis's paper oi1 that bryozoan .... . . f

~LATE { NAOS, C~OXO~rL~V:IL and MeCOP~'LLV~, illus- i

XXX trat ing Dr. W. D. Lang's paper on Naos pagoda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J

428

[ GEOLOGICAL ~IAP OF THE COUNTRY BETWEEN 1 DRYGARN AND ABERGWESYN, i l lustrating Mr.(~

! 436

{ GEOLOGICAL MAP OF THE DISTRICT AROUND TOWYN -I X X X I I ~,ND ABERGY~OLWV~, illustrating Mr. 1~. M.

Jehu's paper on the Geology of that area .... . . 465

'PLATES (GENERAL VIEW OF TIlE ' WESTERN CLIFFS' and an i INVERTED BLOCK OF TIlE WATTON ]:~ED, EYPES- I

MOUTH; TIIE FULL STRATAL SEQUENCE IN TIlE I X X X I I I & X X X I V ~ JUNCTION-~BED (WA~TON :BED) and DETAILS OF 4 9 0

TIIE L1TtIOGRAPIIIC LIMESTONE D, illustrating j Mr. J . F. Jackson's paper on the J'unction-Bed [

i of the Middle and Upper Lias on ~he Dorset I (, Coast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ;

[ Mv=c=zso~'za, HYP==vo~'zA, C~RzrtZlOZgEs, A~D I YX~CV X X Y V I 1 J P~T=09Ea (?), ilhlstrating Mrs. J. Longstaffs | . . . . . . ~ . . . . . . . l paper on th• Brit ish Carbo~,iferous Murchi- f

k soniidte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . j 526

xiv EXPLANATION OF THE PLATES.

PLATES PAGE [ SLAB-IIORIZON, NANTGLYN Ff,AGS, and CRUMPLED I SANDSTONES AT PONTPASTYNOG ; and GIGOLO- I

X X X V I I I & X X X I X ! ~tCAL MaP or' TIIE COUNTRY NEAR D~NBIOII, ~ 556 illustrating Prof. P. G. H. Boswell's paper ! / I on the Geology of the Eastern Part of the Denbighshire Moors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J

/IGNBOUS AND METAMORPIIIC ROCKS FROM TILE) i SuE HILLS; VIEW oF THE ESCARPMRNT OF I [ Tile SUK HILLS and ENTRANCE TO TI1R TURK- !

XL-XLIV~ WAL GORGE; and GEOLOGICAL SKETCH-MAP} 586 OF THE SUK HILLS AND I~EIGIIBOURING RECdONS, KENrA COLONr illustrating the I paper by Mr. V. G. Glendav & Dr. J . /

[. Parkinson on the Geology of flint area ...... ]

[GEOLOGICAL MAp OF TII~. IN,~ER PART OF~ I ~:AtlLENBERG ~AY; GEOLOGICAL ~IAP OFf I I~ORTH-EAsT LAND AND TIlE ADJACENT I ISLANDS; POINT ~SIS and SHOAL POrNT;

XLV-XLIX~ View oF TIlE ~'ORTllEl~S COAST OF NORTh- ~ 615 t ~AST LAND ; CAPE SELANDER AND TIIE ! ENTRANCE TO PALANDER ~AY; and MOU,~T I I IDUN and ALKItANGE, illustrating Dr, K. S. I I Sandford's paper ou the Geology of _N.rth- [, East Land (Spitsbergen) . . . . . . . . . . . . . . . . . . . . . . . . J

CORRELATION TABLE Of certain of the Sections measured in the �9 Western Cliffs' and at Walton Cliff, facing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510

FOLDING TABLE illustrating the Distribution of the Carbonil'erouo Murchisoniid~e ill the British Isles and Belgium, facing . . . . . . . . . . . . . . . 552

P R O C E S S - B L O C K S A N D O T H E R I L L U S T I ~ A T I V E F I G U R E S

BESIDES THOSE IN T H E PLATES.

~AGES FaGs. 1-4. Sagittal section of the Taungs skull a~/d sagittal profiles

of the human skull and of the Orangs and Chim- panzee's skulls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 & 3

5-7. Sagittal profiles of skulls of an unborn child, of a young Orang, and a young Chimpanzee, and also of the Taungs skull . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 & 5

8-11. Sagittal sections of the Taungs skull, of that of a Chim- panzee, of a young Orang, and of a child . . . . . . . . . . . . . . . 6 & 7

PAGE FIG. I. STiroclypeus 91obulus sp. nov . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

FIGS. 2 & 3. DiscocycliT~ oceanica sp. nov . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

FIG. l, Section showing the structure of the cliff at Flying Fish Cove [Christmas Island] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

2. Variation-diagram, basalts of Christmas Island . . . . . . . . . . . . 63

- - Diagram illustrating a method of determining the depth of origin of an earthquake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Fins. 1 & 2, l~ichselia reticulata . . . . . . . . . . . . : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

3 & 4. Frenelopsis hohenegyeri . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

5 & 6. Dadoxylon r . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97, 98

Fro. 1. General diagrammatic section [:Pleistocene deposits of the Great Ouse Basin] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

2. Section in Bordeaux Pit, Little Chesterford . . . . . . . . . . . . . . . 107

3. Section in the pit at the Botanic Gardens, Cambridge ... l l l

4. Section in a trench opposite :No. 83 Oxford Road, Cam- bridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

5. Graph illustrating climatic changes a]ld earth-mo~e- meats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ]37

1. Section of the Black Marl above the birchi bed . . . . . . . . . . . . 150

xvi PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES.

PXGR FrO. 2. Deroc~ras ohesum : l a te ra l and pe r iphe ra l views . . . . . . . . . . . . 175

3. Cru~i lo~eras c~J t i~se ; l a te ra l v iew . . . . . . . . . . . . . . . . . . . . . . . . 176

4. I1wceramu~sfal~i : flattened ]eft va lve . . . . . . . . . . . . . . . . . . . . . . . . tS1

5. tnoceramt~s dorsetensis sp. nov . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

1. Vertical section of the Carboniferous Limestone and Bowland Shales in the Clitheroe district, facing .. . . . . . . 190

2. Diagrammatic section showing the original disposition of the strata between the Chatburn IJimestone and the Hodderense Band, facing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

3. Pustula nodopustulosa sp. nov . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

1. Map illustrating the relation of the Nantlle Slate-Belt to neigtlbouring areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251

2. Detail of 'folded stripe', Clogwyn-mawr, Tal-y-saru uehaf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

3. The Dorothea Grit in Twll-eoeh. Dorothea Quarries ...... 267

4. Dolerite-dyke and quartz-slashes, west side of Ty'n-y- weirglodd Quarry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

5. Junction of the Dorothea Grit and the U0per Stripes t,f the Purl)le Slate Group, west of Tal-y-sarn uehaf ...... 270

6. Fohts on the south-western face of Gloddfa-glytiau, Cilgwyn Quarries, showiug cleavage-planes . . . . . . . . . . . . . . . 271

7. Folds on the north-eastern face of Gloddfa-glytlau ...... 272

8. Map of Twll-mawr, Tel-y-sam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

9. Folds of Dorothea Grit on the south-western face of Twll-mawr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274

10. .North-eastern face of Twll-mawr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27"4

11. Section through grit body on the south-east side of Twll-mawr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275

12. Map of the Tyddyn Agnes Quarries . . . . . . . . . . . . . . . . . . . . . . . . . . . 276

13. Section through the Tyddyn Agaes Quarries . . . . . . . . . . . . . . 277

14. Section through Twll-glas, Fronheulog . . . . . . . . . . . . . . . . . . . . 278

15. Section across Gallt-y-fedw Blue Quarry . . . . . . . . . . . . . . . . . . . . . 279

16. Section through South Dorothea Quarry . . . . . . . . . . . . . . . . . . . . . 279

17. Section through Twl[-eureka, Pen-yr-orsedd . . . . . . . . . . . . . . 280

18. Fold of Dorothea Grit, north-west side of Moel Tryfan Quarry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281

19. Section along the line of the Moel Tryfan tunnel . . . . . . . . . 2S2

20, Exposures on the summit of 5Ioel Try fan . . . . . . . . . . . . . . . . . . 283

PROCI~SS-BLOOKS AND {}]:HER [LLUSTR:kTIVE FIG-URES. XV'il

]3AGE lgc~. 21. Detail hi" t lm.iuueliou of tile Cilgwyn CouglolHerate and

Tryfan Silts in the Moel Tryfan Tunnel . . . . . . . . . . . . . . . . . . 284

'2"2. Pre-Cambriau rhyolite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

23. Crystal-tuff showing �9 mor ta r ' - s t ruc ture . . . . . . . . . . . . . . . . . . . . . 286

24. Hornblende-andesi te , Clogwyn Melyn . . . . . . . . . . . . . . . . . . . . . . . . 288

25. Crushed rhyolite, south side of Caerengan . . . . . . . . . . . . . . . . . . 289

2ti. Chlorite-quartz-grit , top of the Glog Gro~p, South l)(~roT,hea Quarry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29!

27. Tourmaline-crystals in brown-mica matrix in a coarse grit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292

28. Diagram showiwlg structural directions in a block o[" rock quarr ied at ~an t l l e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298

1. Section alo~lg the Cireinaich Burn . . . . . . . . . . . . . . . . . . . . . . . . . . . 313

2. Section along Creag all Lochan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314

3. Section aloug Ihe headwaters o[' th~ Allt Da Eig . . . . . . . . . 314

4. Section along the headwaters of the Allt Cbobhair . . . . . . 314

5. Over thrust on An Stile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

6. Section across Ben Lawars, from the southern shoulder to An Stfic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32~)

7. Ben Lawers summi t : major, minor, aud minimum folding in tim band ~f qHartzite 5 c . . . . . . . . . . . . . . . . . . . . . . . . 321

8. [Map showiug thrusts, etc. ill the neighbourhood of' Locilan Mhadaidh] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322

9. Sectiun from Fearnau t~ Creag Mhadaidh . . . . . . . . . . . . . . . . . . 324

10. Diagram illustrating the possible relations of the beds of the Ben Lawers range af ter maximunl folding . . . . . . . . . 327

I. :Erratic of quartzite, split by insolation . . . . . . . . . . . . . . . . . . . . . 336

2. t )or t ion of the column of / Zsocri,us sp . . . . . . . . . . . . . . . . . . . . . . 338

3. Geueralized vertical section at Muloowurt ina (South Australia) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340

1. Map of part, of the Caribbean Sea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353

.20. Geological map of' Caymaa Brae . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358

3. Section along the length of Cayman Brae . . . . . . . . . . . . . . . . . . 362

4. Section across Cayman Bl'ac . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363

5. Geological map of Li t t le Oayman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364

6. Section along Li t t le Cayman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366

7. Section across Lit t le Cayman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367

8. t~eological map of GraTed Cayman . . . . . . . . . . . . . . . . . . . . . . . . . . . 368 VOL. LXX.XII. b

, , ~

XVlll PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIOURES,

~AOE FrO, 9. Section east and west through Grand Cayman . . . . . . . . . . . . 369

10. Section through Grand Cayman, from the northern coast to Frank Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370

l l . Section from British Honduras along the Cayman Ridge and Sierra Maestra to Haiti . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374

12. Profile across Cuba and the Isle of Pines to Grand Cayman and the Pedro Bank, crossing tl:e Bartlett Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374

13. Fault-blocks of the Lesser Caymans . . . . . . . . . . . . . . . . . . . . . . . . . . . 379

Map of the Clent Hill district . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 ~

Fins 1-4. AnlhracopuTa britannica, A. ohioe~sis, and A. cermilio~- e;zsis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408

Fro. 1. (~arth Gri t : section through fractured ' nodules' and ' pebbles' of slate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412

2. Portion of the etehe,1 ce!luliferons surface of Bolopora uJtdosa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415

3. Portion of a longitudinal section of a 'nodule ' , Bryn Glaa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416

4. Layer showing the porous zos walls characteristic of the Ceramoporoids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417

FIGs. 5 & 6. Tangential sections of .Bolopora uudosa . . . . . . . . . . . . . . . . . . . . . . . . 419

Fro. 7. Diagrammatic section illustrating the mode of growth of B. undosa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422

l. Leototype of ,~aos pagoda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430

2. Diagrams of the internal structure of Silurian corals ...... 431

I. Map illustrating the outcrop of the Bale Series between Llanwrtyd and Aborgwesyn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440

2. Vertical section through the Silurian rocks of the Aber- gwesyn-Drygarn country, facing . . . . . . . . . . . . . . . . . . . . . . . . . . . 442

3. Plan of the Nant Trawsgyrch and Bryn Clun localities... 442

4. Plan of sect, ions along iNant Rhydgoch and Nant Shin- gins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445

5. Plan of section ahmg the Irfon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -152

6. Diagrammatic section from ~outh-east to north-west across tho Abergwesyn country . . . . . . . . . . . . . . . . . . . . . . . . . . . 458

7. Diagrammatic section illustrating the characteristic features of the outcrops of the Yalentian rocks . . . . . . . . . 460

1. Vertical section through the Ordavician rocks . . . . . . . . . . . . . . . 468

2. Diagrammatic section across the Tal-y-Clyn Valley, south-west of Dolgoch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 472

'd. General section from Craig yr Aderyn to Mynydd Cein- eaer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474

PROCESS-BLOCKS AND OTHER ILLUSTRh.TIVE FIGURES. x i x

Fro. 4. General .~ection from R h y d - y r - O n e n to the Afon

3~

1.

F[os. 2 & 3.

Fro. 1.

2.

Fins. 3 & 4.

F~G. 5.

6.

7.

8.

Fins. 9 & 10.

Fro. l l .

12.

13.

P^~E

Dyffr) n-gwyn Valley . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476

5. Sketch-map illustrating the general structure and the p~)sitions of the axes of folding with reference to the Tal-)-llyn or Bale Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 482

1. Geological sketch-map of Foel Gasyth, near Denbigh ... 570

2. Geological sketch-map of the neighbourhood of Porth ... 571

Geological section from the centre of the Denbighshire Moors to the Vale of Clwyd at Llanrhaiadr . . . . . . . . . . . . 579

Map ol' the north-western part of Kenya Colony . . . . . . . . 587

I)iagra,ns showing relations between the variables SiO2, Al~O3, and K~O in Kenya gneisses . . . . . . . . . . . . . . . . . . 599, 604

Topographical sketch-map of Spitsbergen . . . . . . . . . . . . . . . . . . 616

North-eastern district [of Spitsbergen] : section from the shore of the mainland to the outer islands . . . . . . . . . . . . . . . 618

P la , of, and section through, Low Island . . . . . . . . . . . . . . . . . . 624

Map of part of the Sledging Base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 628

Section across the Sledging Base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 630

Map showing the directions of Caledonian folding in ,.North-East Land . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632

Diagram tff flow at Point O 2, Wahlenberg Bay .. . . . . . . . . . . 634

Plan of Ulve Bay and cliff-section at the eastern end of the bay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 640

Upper part of Ivory Gull Cliff, Wahleliberg Bay .... . . . . . 642

Section from Ulve Bay to Mo!jnt Idun . . . . . . . . . . . . . . . . . . . . . 644

Region of Hinlopen Strait : sketch-map showing ~the known and supposed lines of dislocation, etc . . . . . . . . . . . . . 656

D a t e s o f I s s u e o f t h e Q u a r t e r l y J o u r n a l f o r 1926.

.g~,. 325= March 17th, 1926.

No. 326--July 3rd, 1926.

No. ,127--October 19th, 1926.

No. 328-- l:)ecen,be:. 31st. 1926.