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PROCEEDINGS

GEOLOGISTS' ASSOCIA'nON.

{FOUNDED taea.)

VOLUME THE SIXTEENTH,
1899-1900.

EDITED BY

H. A. ALLEN, F.G.S.

(Authors alone are responsible for the opinions and facts stated in
their respective Papers,)

LONDON.

1900.

or,

499925

LIST OF OFFICERS AND COUNCIL

OF THE

GEOLOGISTS' ASSOCIATION.

ELECTED 2ND FEBRUARY, 1900.

President :
W. Whitakcr, B.A.Lond., F.R.S., A.I.C.E., F.G.S.

Vice-Presidents :

H. W. Monckton, F.L.S., V.P.G.S.
E. T. Newton, F.R.S., F.G.S.,
F.Z.S.

C, Davies Shcrborn, F.G.S., F.Z.S.
J. J. H. Teall, M.A., F.R.S.,
Pres. G.S.

Treasurer :
R. S. Hemes, M.A., Sec. G.S.

Secretaries :

Percy Emary, F.G.S., 12, Alwyne Square, Canonbury, N.
Bedord McNeill, AssocR.S.M., Assoc.M.I.C.E., F.G.S.

Editor :
H. A. Allen, F.G.S., 28, Jermyn Street, S.W.

Librarian :
W. J. Atkinson, F.G.S.

Council :

H. A. Allen, F.G.S.

W. J. Atkinson, F.G.S.

L. L. Belinfante, M.Sc, B. fes L.

Geo.^C. Crick, A.R.S,M„^F.G.^.

Percy ^rtlaKv, AG.S.« - * •

Hen^TU'<^>'9.Sr.;^;.:; .;

Miss Mary Foley, B.bc

R. S. Herrics, M.A., Sec.G.S.

R. Holland.

Dr. Edward Johnson.

A. S. Kennard.

Frederick Meeson.

Horace W. Monckton, F.L.S.,

F.G.S.
E. T. Newton, F.R.S., F.G.S.
A. E. Salter B.Sc, F^G.S
C.'Davies Sl^rborn.'F.G.S., F.Z.S.
W.P. '^. Sieyjifig, F.G.S;
J.' J. H. teall, M.A., F.R.S.,

Pres.G.S.
W. Whitaker, B.A.Lond., F.R.S.,

F.G.S.
Miss Eva Whitley, B.Sc.
A. C. Young, F.C.S.

CONTENTS.

Notes on the Teeth of Sharks and Skates from English Eocene Forma-
tions. By A. Smith Woodward, F.L.S., F.G.S. (^lUusiratni.) i
Contributions to the Geology of the Thame Valley. By A. M. Daviks,

A.R.C.S., B.Sc, F.Cf.S. (^Illustrated, Plate II.) 15

Ordinary Meeting, November 4th, 1898 S9

Ordinary Meeting, December 2nd, 1898 60

The Natural History of Cordierite and its Associates. (^Presidential

Address, 1899.) By J. J. H. Tkall, M.A., F.R.S., F.G.S. ... 61
The Drainage of Cuestas. By Prof. W. M. Davis, of Harvard

University. (Illustrated,') 75

Annual General Meeting, February 3rd, 1899 94

A Sketch of the Geology of Central Brittany. By Dr. Ch. Barrois. loi

Visit to Museum of Mr. W. H. Hudleston, March nth, 1899 I3S

Excursion to.Seaton, Sidmouth, Budleigh Salterton, and Exeter ... 133

Excursion from Winchfield to Wokingham, April 8th, 1899 153

Excursion to Walton-on-ihe-Hill and Betchworth, April 15th, 1899 ... IS5

Excursion to the Thame District, May 6th, 1899 IS7

Excursion to llford. May 13th, 1899 160

Excursion to Reigate, June 3rd, 1899 162

Excursion to Staines, April 22nd, 1899 163

Ordinary Meeting, March 3rd, 1899 164

Ordinary Meeting. April 7th, 1899 164

Ordinary Meeting, May 5th, 1899 164

Ordinary Meeting, June 2nd, 1899 164

A Sketch of the Geology of the Lower Carboniferous Rocks of Derby-
shire. By H. H. Arnold Bkmrosk, M.A., F.G.S 165

Long Excursion to Derbyshire, August 2nd, 1899 221

Excursion to Nottingham, August loth, 1899 225

Excursion to Wcldon, Dene, and Gretton, April 29th, 1899 226

Excursion to Brittany, May i8th, 1899 231

Excursion to Central Brittany, May i8th, 1899 240

Excursion to Laval, May 25th, 1899 242

Excursion to Bushey and Harrow Weald, May 27th, 1899 243

Excursion to Rickmansworth and Harefield, June loth, 1899 244

Excursion to Lichfield and Cannock Chase, June 17th, 1899. (Illustrated,) 246

Excursion to Aldrington, Brighton, and Rottingdean, June 24th, 1899... 248

Excursion to Cuxton and Burham, July 1st, 1899 249

Excursion to Chiltern Hills, July 8th, 1899 251

Excursion to Guildford and Godalming, July 15th, 1899 254

Excursion to Claygate, Chessington, and Oxshott, July 22nd, 1899 ... 256

Excursion to Charlton, Erith, and Crayford, September 9th, 1899 ... 257
Excursion to British Museum, Jermyn Street Museum, and Natural

History Museum, September nth, 1899 257

IV CONTENTS.

PACK

Ordinary Meeting, July 7th, 1899 258

The Raised Beach and Rubble-Drift at Aldrington. By F. Chapman 259
The Pleistocene Deposits of the Ilford and Wanstead Districts. By

M. A. C. HiNTON. (JllustraUd:) 271

The Pleistocene Non-Marine Mollusca of Ilford. By A. S. Kennard

and B. B. Woodward, F.G.S., F.R.M.S 282

Ordinary Meeting and Conversazione, Friday, November 3rd, 1899 ... 286

Ordinary Meeting, Friday, December ist, 1899 288

Ordinary Meeting, Friday, January $th, 1900 288

The Zones of the White Chalk of the English Coast. Part I.— Kent

and Sussex, by Dr. A. W. RowE, F.G.S. With Appendices by

Dr. J. W. Gregory, F.G.S., F.Z.S., and Dr. Kitchin, M.A.,

F.G.S. The Cliff Sections by C. Davies Shbrborn 289

The Natural History of Phosphatic Deposits. By J. J. H. Teall, M.A.,

F.R.S 369

Ordinary Meeting, February 2nd, 1900 387

Ordinary Meeting, March 2nd, 1900 387

Annual General Meeting, February 2nd, 1900 38g

Wind-worn Pebbles in the British Isles. By F. A. Bather, M.A.,

F.G.S. (IllustraUd, Plate XI :) 396

Ordinary Meeting, May 4th, 1900 420

A New Rhaetic Section at Bristol. By W. H. WrcKES 421

Visit to the Museum of the Geological Society, February loth, 1900 ... ^23
Excursion to Newton Abbot, Chudleigh, Dartmoor, and Torquay.

(^Illustrated, Plate Xll.y Easter, 1900 425

Excursion to Wimbledon and Kingston, April 28th, 1900 443

Visit to the British Museum (Natural History), March 17th, 1900 ... 445

Excursion to Hilchin and Arlesey, May 5th, I9CX> 446

Excursion to Hertingfordbury, Bajrford, and Brickenden Green, May

19th, 1900 447

Notes on the Geology of the English Lake District. By J. E. Marr,

M.A., F.R.S. (Illustrated,') 449

Zonal Features of the Chalk Pits in the Rochester, Gravesend, and

Croydon Areas. By G. E. Dibley, F.G.S., with an Appendix on

a Bone from the Chalk of Cuxton. By E. T. Newton, F.R.S. 484

Excursion to Eastbourne and Seaford, May 26th, 1900 500

Excursion to Boxmoor, May 12th, 1900. (^Illustrated) 501

Excursion to Malvern and District, Whitsuntide, June 2nd, 1900 ... 503

Excursion to Caterham, Godstone, and Tilburstow, June i6th, 1900 ... 510

Excursion to Guildford, June 23rd, 1900 512

Excursion to Silchester, June 30th, 1900 513

Excursion to Kettering and Thrapston, July 7th, 1900 516

Excursion to Purley, Kenley, and Whyteleafe, July 14th, 1900 518

Excursion to Winchfield and Hook, July 21st, 1900 519

Excursion to Grove Park, July 28th, 1900 522

Excursion to Netley Heath, August nth, 1900 524

Long Excursion to Keswick, August 20th to August 25th, 1900 ... 526

Excursion to Strood and Hailing, September 8th, 1900 532

Excursion to Orpington, September 22nd, 1900 533

Ordinary Meeting, June 1st, 1900 535

Ordinary Meeting, July 6th, 1900 535

LIST OF ILLUSTRATIONS.

PAGE

Transverse sections of lower dentition of Afyliobaiis dixoni and Af. striatus 4

Eocene Selachian teeth (Plate I) ^4

Key-map of the Thame Valley ^6

Section from Haddenham to Cuddington 23

Sketch-map of Haddenham district. Bucks. 54

Comparative series of vertical sections in the Thame Valley (Plate II) 5^
Diagram of a cuesta developed by the mature denudation of a coastal

plain 77

Diagram of a cuesta as a transitional form between a mesa and a ridge... 7^

Section of the Swabian Alb from Heilbronn to the Danube 79

Diagram of the relation between consequent streams and a cuesta ... 80

Diagram of the Schmiecha at Kaiseringen So

Sketch of the valley of the Schmiecha from Ebingen 81

Section of the Swabian Alb between the Eilachand the Schmiecha ... 82

View of the divide between the Eilach and the Schmiecha 83

Diag^m of a cuesta in two cycles of denudation 85

Section of the Allegheny Plateau 86

Section of Pine Mountain, Kentucky 87

Diagram of a narrow meandering valley with symmetrical spurs ... 89

Diagram of a broadened meandering valley with unsymmetrical spurs ... 90

Diagram of a broadened valley with cusp remnants of spurs 9°

Diagram of a broadened valley with smoothed sides 9^

Sketch of the valley of the Windrush 9°

Diagram of the valley of the Coin about Withington 9^

Sketch-map of Brittany 102

A deformed granite pebble with quartz-veins 106

Section from Corps-Nuds to the Mriohan Mill 107

Section across the synclinal of Polign6 108

Section of the Brehec Cliffs 109

Map of the Armorican series in the Vilaine Valley no

Section of the Ordovician beds around Poligne in

Section across the synclinal of St. Aubin d'Aubign6 I14

Sketch-map of the St. Aubin d'Aubign6 massif 115

Section through the granitic mass of Mont Dol 118

Sketch-map showiR|r the eastern termination of the three granitic masses

of Southern Brittany 119

Map of the eastern extremity of the Grandchamp massif 121

Section from St. Eutrope to St. Jacut 122

Section across the three granitic masses of Morbihan 124

Map showing the contact of granite near Pledran ... 128

Section showing the folding of the graphitic beds around Pledran ... 129

VI LIST OF ILLUSTRATIONS.

PAGE

Sketch-map showing the distribution of the pre-Cambrian hornblendic

granite, Bay of St. Brieuc 130

Section along the South Devon cliffs from Exmouth to west of Lyme

Regis 137

Cliff west of Budleigh Salterton 14S

Section in railway cutting, Walton-on-the-Hill iS^

Sketch-section across Derbyshire 167

Section through Crich Hill 176

Map of the District N.E. of Bonsall (Plate III) 186

Basalt agglomerate in volcanic vent Hopton ; Syncline and Anticline

in Yoredales, Tissington (Plate IV) 188

Section across Edale and the Castleton Valley 190

Plan of necks and bedded tuff at Grange Mill 199

Section across volcanic neck and stratified tuff at Grange Mill 200

Intrusive dolerite, Tideswell Dale ; Lava and tufaceous limestone

Miller's Dale (Plate V) 204

Section across Tideswell Dale 209

Section from Miller's Dale to Tideswell 209

Geological map of Tideswell Dale (Plate VI) 210

Sections through Tissington Cutting, Highway Close, Bam Cutting, and

Crake Low Cutting (Plate VII) 212

Section from Brewood to Lichfield ... 247

Sections of Raised- Beach and Rubble-Drift at Copperas Gap ... 261, 268

Raised-Beach and Rubble-Drift at Aldrington 262

Section of Concretionary Sandstone from the Raised-Beach ... ... 263

Sectionsof Contorted Drift, I Iford 274. 275

6^m/afri>(«f from Margate 298

ZeugiopUurus rowti 354

Teri6ratu/inarowei(V\iiteViU) 358

Bourgueiicrtnus (Plate Vill) 3S8

Section along the cliff-face from Brighton to Eastbourne (Plate IX) ... 368

Section along the cliff-face from Dover Castle to Kingsdown (Plate X) 368

Section along the cliff-face between Pegwell Bay and Gore End (Plate X) 368

The Bowdon Pebble 397

A Pebble from Reval 408

Wind-worn Pebbles (Plate XI) 420

Coast Section from Babbacombe to Watcombe ... 434

Sketch-plan of Kent's Cavern 437

Section at Wolborough Church 440

Bowerman's Nose, Lustleigh (Plate XII) ... ... 442

Lignite- pit, Kingsteignton (Plate XII) 442

Volcanic series from Der went water to Conistoii 4S4

Map of outcrop of rocks west of the head of Windermere 466

General Structure of Lower Palaeozoic rocks of the Lake District ... 468

Maps of the Gravesend and Rochester areas 485

Map of the Croydon Area 491

Dentigerous bone from the Chalk of Cuxton 497

Plan of Bennet's End Brickfields S^i

Section at do. do. 502

Section across the Malvern Range S04

LIST OF GENERA AND SPECIES — LIST OF LECTURES. Vll

PACE

Section across Cowleigh Park and High Wood 5^4

Section across High Wood and North Hill 504

Section across the Southern part of Raggedstone Hill 506

Section across the South-western part of Raggedstone Hill 507

Section across Midsummer and HoUybush Hills 507

Section along the line of the Malvern Tunnel 507

Provisional Map of volcanic rocks of the Lake District 527

Old Red Conglomerate, Pooley Bridge, Ullswater (Plate XIV; ... 532

Drift of Glaciated Rock, north of Rosthwaite (Plate XIV) 532

LIST OF GENERA AND SPECIES

FIGURED AND DESCRIBED IN

VOLUME XVI.

Acanthias orpiensis (Winkler), PI. I, figs, i, 2, p. 2.
Squatina sp., PI. I, figs. 3-5, p. 2.
Myliobatis dizoni, Ag., fig. I, p. 4.

„ striatus, Buckl., fig. 2, p. 4.

Notidanus serratissimus, Ag., PI. I, figs. 6, 7, p. 6.
Xiphodolamia sp., PI. I, figs. 8, 8a, by p. 6.
Cestracion sp., PI. I, fig. 9, p. 6.
Odontaspis rutoti (Winkler), PI. I, figs. 10, 1 1, p. 7.

cuspidata (Ag.), PI. I, figs. 12-14, p. 7.

elegans (Ag.), PI. I, figs. 15-18, p. 8.

macrota (Ag.), PI. I, figs. 19, 20, p. 9.
Lamna vincenti (Winkler), PL I, figs. 21, 22, p. 10.
Otodus (Hypotodus) trigonalis (Jaekel), PI. I, figs. 23, 24, p. 10.
Oxyrhina eocaena (A.S.W.), PI. I, figs. 25, 26, p. 11.
Galeus sp., PL I, figs. 27, 28, p. 12.
Galeocerdo minor, Ag., PI. I, figs. 29, 30, p. 12.

,. latidens, Ag., PL I, figs. 31, 32, p. 12.

Zeuglopleurus rowei, Gregory, p. 353.
Tcrebratulina rowei, Kitchin, PL VIII, figs. 1-5, p. 355.

LIST OF LECTURES, 1899-1900.

"The Glaciers and Fiords of the Bergen District of Norway," by

H. W. Monckton, F.L S., F.G.S 100

"The Geology of the Isle of Man." by G. W. Lamplugh, F.G.S. ... 163

"The Last Great Eruption of Etna," by F. W. Rudler, Pres. Am hi op.

Soc., F.G.S 288

" Some Features of the Recent Geology of Western Norway," by

H. W. Monckton, F.L.S., V.P.G.S 420

"Our Older Sea-Margins," by Sir Archibald Geikie, D.C.L., LL D.,

F.RS 535

ADDENDA ET CORRIGENDA.

Page 62, line 19, for ** a round " re<id ** around."

„ 62, line 3 from bottom, /?r ** other " read '* older."

„ 64, line 9 from bottom,y&r *' plain *' read ** plane."

„ 125, line IT -t for " magna " read "magma."

„ 178, To the heading, " Caverns " add " and underground water."

„ 275, Fig 2 is inverted.

„ 466, Fig. 2, The bed ** 2 *' on the west side of the fault should be about

half mile farther south. The positions of the beds are correctly stated

in the text.

INSTRUCTIONS FOR BINDING AND DATES
OF PUBLICATION.

Part

Pages

Plates

Issued

1.60 .. .

I
11

to face
1'

p. 14

t, S8

March 14th. 1899.

61-100 .

May 8th, 1899.

IOI-164 .

July i8ih, ifi99.

£65-220 .

III
IV

„ 186
.. 188

August 29th, 1899.

t, 204

„ 210

VII

„ 212

221-260 .

December 15th, 1899.

261.368 .

VIII

» 358

March 19th, 1900.

Cancel 259 and 260

IX and X „

„ 368

369-424 .

„

., 420

June 2oth, 1900.

42S-448 .

XII

tt 442

July i6th, 1900.

449-500 .

September 4th, 1900.

501-536 .

XIII

.. S27

November 24th, 1900.

XIV

,. 532

PROCEEDINGS

OF THE

GEOLOGISTS' ASSOCIATION.

VOL. XVI,

NOTES ON THE TEETH OF SHARKS AND
SKATES FROM ENGLISH EOCENE FOR-
MATIONS.

By a. smith woodward, F.L.S , F.G.S., of the British Museum (Natural

History).

(Read June yrd^ 1898.;

[PLATE I.]

THE sharks and skates of the Eocene period are very
imperfectly known. They are represented by a few
nearly complete skeletons in the fissile limestone of Monte
Bolca* and Monte Postalet in Northern Italy, and by
the nearly complete skeleton of one genus J in the marly
Green River Formation of Wyoming, U.S.A. In other
localities they are known merely by portions of dentition,
detached teeth, cartilage, and vertebrae. Nevertheless, it is
evident that the genera and species indicated by these fragments
are closely similar to those surviving in existing seas. The
fossils can therefore be directly compared with the corresponding
hard structures of the genera of the present day ; and if the
parts were in all cases distinctive, it would be an easy task to
restore the Eocene Selachian fauna from the abundant materials
now collected in museums. Unfortunately, however, as already
emphasised on a former occasion, § the detached teeth of sharks
and skates are not always distinctive; and the generic and
specific determination of them is little more than guesswork,
while that of the associated vertebrae is, if possible, even more
unsatisfactory.

• O. Jaekel, *' Die eoc&nen Selachier vom Monte Boica " (Berlin, 1804).

t Kner and Steindachner, " Neue Beitrige zur Kenntniss dcr fossilen Fischc Oesierreichs,"
Denkschr. k, Ahad. Wist., math.'natutw. CI., vol. xxi (1863), p. 3a, PI. VI, Fig. 2

X Xiphotrypmy E. D. Cope, "Vertebrata of the Tertiary Formations of the West,"
Book I (/?</. U.S. GeoU Surv. Territ , vol. iii, 1884), p. 50, PI. I, Figs, i, 5.

§ A. S. Woodward, "Notes on the sharks' Teeth from British Cretaceous Formations,"
Proc, Gtol. Assoc., vol. xiii (1S94X p. 190.

February, 1899]. i

2 A. SMITH WOODWARD ON THE

In presenting these notes on the Selachian teeth from British
Eocene Formations, it must therefore be understood that the
proposed nomenclature and arrangement of the fossils under
consideration are in most cases quite tentative and liable to
change when the fishes or even the jaws to which they belong are
discovered in their entirety. In some instances the writer has
already found reason to modify the determinations suggested in
Part I of the " Catalogue of Fossil Fishes in the British Museum,"
published in 1889. The members of the Geologists' Association
are in an especially favourable position for the further elucidation
of the subject ; and it is hoped that the following brief outline of
our present knowledge and speculations will lead to new
advances. These notes merely record the species which it seems
possible to recognise. Students desiring detailed references to
the literature and synonymy may consult the Catalogue just
mentioned.

Sub-Order TECTOSPONDYLI.

Family SPINACIDyE.

Genus Acanthias.

Though ranging from the Cretaceous upwards, the spiny dog-
fishes are only known from the English Eocene by a few small
teeth discovered by Mr. Sydney C. Cockerell in the Woolwich and
Reading Beds of Chislehurst. These teeth closely resemble
those of the existing Acanthias^ and have been referred to this
genus by Jaekel.* Two of them are shown of the natural size in
PL I, Figs. I, 2. They have a very broad and low, laterally-com-
pressed crown, with the anterior margin arched and the posterior
margin deeply notched ; and there are sometimes faint traces of
serrations on the sharp edge. Identical teeth have been described
from the Heersian Beds of Belgium under the name of Notidanus
orpiensiSy\ and the species is wrongly referred to Carcharias
(Scoliodon) in the British Museum Catalogue (torn, cit,^ p. 436),

Family SQUATINIDyE.
Genus Squatina.

Two characteristic teeth of the " angel-fish," Squatina, were
discovered by Mr. N. T. Wetherell in the London Clay of
Highgate Archway, and a third example by Mr. Cockerell in the
Woolwich and Reading Beds of Chislehurst. They are shown,
of the natural size, in PL I, Figs. 3-5, but are insufficient for specific
determination.

• O. Jaekel. op. cit., p. 156.
T C. W nkler, Arckiv, Mus* TtyUr, voU iv (1876), p. 12, PI. I, Figs 13—17.

teeth of sh^kcs axd skates from english eocene.

Family PRISTID.£.
Genus Pristis.

PortiODs of the lenuurkable toothed snout of the *^ saw-Ash/'
Pristis^ have long been known from the Brgcklesham Beds of the
Sassez const ; and detadied rostral teeth of Pristis bisuIctUa^ as
the ^)ecies is rtttmed,"^ are not uncommon fossils in that
formation. These teeth are laterally-compressed pegs, grooved
along the posterior border, exactly similar to those of most
lirmg species. Indeed, it is dear that the unique rostrum
erf" PrisHs was already fully developed in the Eocene period.
Similar rostral teeth occur in the Barton Clay of Hampshire, one
having been named P, kasiingsia by Agassiz (torn, cit.^ p. 38a*) ;
and there is a curiously bent form, P, contoria^\ also in the
Bracklesham Beds. The genus is not yet known from the
Lower Eocene.

Family MYLIOBATID.E.
Genus Myliobatis.

The great " eagle-rays " with a compact pavement of flattened
crushing teeth in each jaw must have been very abundant in
Eocene seas. Fragments of their dentition are common in the
London Clay, the Bracklesham Beds, and the Barton Clay ; and
all three surviving genera seem to occur. Of these, Myliobatis is
by far the commonest, and evidently represented by several
species, which are not readily distinguished. The dentition of
each jaw in this genus comprises large, flattened, hexagonal teeth,
arranged in seven antero - posterior series. In very young
individuals, the teeth are all approximately of equal si/e, but
quite early in life the median teeth begin to become relatively
very broad, and as the animal grows, this disproportion of the
median teeth gradually becomes greater and greater. When
unworn or unabraded, the grinding surface of the teeth is covered
with a thin enamel-like layer of gano-dentine, usually marked
with antero-posteriorly directed striations ; but when this layer is
removed, the tooth has a punctate appearance, owing to the
exposure of the vertical nutritive canals traversing the under-
lying vascular dentine. In naming the fossils, it is tlius necessary
to take into account the size of the specimen, and remember that
the surface markings depend upon the state of preservation. It
is also necessary to note that the dental plate of the lower jaw is
flat, while that of the upper jaw curves round the supporting

• L. Agassiz, " Rirch. Poiss. Foss.,' vol. Hi (1843), p. 382*, PI. XI.I.

t F. DuKOO, "Geology and Fossils of Susmx " (1850), p. 202, PI. XII, KiK^. c, 10.

A. SMITH WOODWARD ON THE

cartilage. No less than fifteen names have been given to English
Eocene specimens, but a study of the very large collection in the
British Museum, with the considerations just mentioned in view,
suggests that only five species are represented.

Fig. I. — Transverse Section of Lower Dentition of
Myliobatis dixoni^ Agassiz.

I. Myliobatis dixoni^ Agassiz. This seems to be the com-
monest species in the Bracklesham Beds and Barton Clay, but it
has not yet been definitely recognised in the London Clay. The
teeth are very massive and conspicuously striated when unabraded ;
in transverse section (Fig. i) the surface of the crown is shown to
be arched from side to side. The lateral teeth are much longer
than broad, and even in the largest specimens the median teeth
are rarely more than five times as broad as long.

Fig. 2. — Transverse Section of Lower Dentition of Myliobatis

striatus, BUCKLAND.

2. Myliobatis striatus^ Buckland. This is another large
species confined to the Bracklesham Beds and Barton Clay, with
the dental crown very little arched from side to side (Fig. 2).
The median teeth in the larger specimens are at least six times as
broad as long, and the lateral teeth always longer than broad.

3. Myliobatis goniopleurus^ Agassiz. A rarer species ap-
parently occurring both in the London Clay and the Brackles-
ham Beds, though the only known specimen labelled "Isle of
Sheppey " is the type. The teeth are of similar proportions to
those of M, striatus, but thicker and considerably raised in the
middle.

4. Myliobatis toliapicus^ Agassiz. A common species in the
London Clay, Bracklesham Beds, and Barton Clay. The
dentition is comparatively thin, and the contour of the crown is
flat in the lower jaw, nearly so in the upper jaw. The median
teeth in the adult are at least six times as broad as long, while
the lateral teeth are as broad as long, more or less diamond-shaped.

TEETH OF SHARKS AND SKATES FROM ENGLISH EOCENE, 5

When preserved the grinding surface is seen to be remarkably
smooth.

5. Myliobatis latidens^ A. S. Woodward. This is a very small
species from the Bracklesham Beds, the largest known dentition
measuring only about three centimetres across. The lower
dentition is flattened, and the upper median teeth are only
slightly arched from side to side. The median teeth in the adult
are not less than eight times as broad as long, while the
lateral teeth are always at least as broad as long.

The characteristic serrated tail-spines of the Myliobatidse
also occur in the English Eocene, and five have received names
(Myliobatis acutus^ Ag., M, canaliculatus^ Ag., M, lateralis^ Ag.,
M. marginalise Ag., and M, aweni^ Ag.) ; but they cannot be
either generically or specifically determined, and some of these
fossils may belong to Trygonidse.

It is interesting to add that a complete fish with the dentition
of Myliobaiis is known from the Upper Eocene of Monte Bolca
in Northern Italy.'*' This is supposed to differ from the recent
AiyUobatis in the continuous extension of the pectoral fins
forward to the front of the head, and is thus placed in a distinct
genus, PromyliobatisA The English Eocene teeth may have
belonged to a similar fish, but no distinctive features can be
observed in the dentition.

Genus Rhinoptera or Zygobatis.

Rhinoptera has the teeth in five or more antero-posterior
series, the middle being the largest, the first — or first and second
— lateral series on each side somewhat smaller, and the others
approximately as broad as long. The dentition is bent round
the cartilage of each jaw. The only known evidence of this
genus in the Eocene is a unique jaw in the British Museum
from the London Clay of Sheppey.J The teeth in this specimen
are transversely channelled on the crown, and arranged in nine
antero-posterior series.

Genus Aetobatis.

As in Myliobatis the dentition in this genus is beni ound
the supporting cartilage of the upper jaw and forms a flat plate
in the lower jaw; but there is only one very broad seres cf
teeth. The upper teeth are much like those of Myliobatis, oniy
differing in their truncated lateral ends ; but tht lower teeth are
more or less strongly curved or V-shaped. Such teeth occur in
all the English Eocene deposits, but mostly detached and not
specifically determinable. Six names have been proposed for

• A. de Zigno, Mem, R, Istit. Vemto, vol. xxii (1887), p. 681, PI. V, Fig. i.
t O. Jaekel, of. cit., p. 15a.

X RJUtufJUrm dmmn\ A. S. Woodward, "Catal. Foss. Fishes B. M," Pt. 1 (1889), p.
ia6, PI. Ill, Fig. 6.

O A. SMITH WOODWARD ON THE

them, but at present it is only possible to distinguish two forms,
a flattened, low-crowned tooth (A, irreguiaris^ Agassiz), and a
thickened tooth raised in the middle {A, marginalise Agassiz).

Sub-Order ASTEROSPONDYLI.

Family NOTIDANID^,

Genus Notidanus.

The saw-like teeth of Notidanus are not uncommon in the
London Clay, but they seem to be unknown in the Bracklesham
Beds, and they are rare in the Barton Clay. All the known
teeth from the London Clay appear to belong to one small
species, Notidanus serratissimus, Agassiz, and they exhibit tUe
usual variations. Some, which probably belong to the upper jaw
(PI. I, Fig. 6), have a large principal cusp, with strong
serrations in front, and four or five diminishing cusps behind.
Other teeth (PI I, Fig. 7), which are referable to the side of the
lower jaw, exhibit as many as seven or eight cusps behind the
principal cusp. The Barton Clay teeth are larger than these, and
are probably to be identified with Notidanus primigenius^ Agassiz,
which is common in the Lower Miocene of the Continent, and
also occurs in the Upper Eocene of North Germany.

The upper front teeth of the existing Notidanus are simple
awl-shaped cusps, and it seems not unlikely that the so-called
Xiphodolamia ensis^ described by Leidy* from the " marls of
New Jersey," is founded on some of these. Three teeth obtained
from the London Clay of Sheppey by the late Mr. Wetherell are
apparently of the same nature, only differing from the usual form
in the crown (PI. I, Figs. 8, 8«) exhibiting one cutting edge and
a rounded border instead of two cutting edges. The crown is
fixed obliquely on a small, nearly square base (PI. I, Fig. 8^),
which is imperfectly divided into two roots. A broken crown in
the Wetherell collection proves that it is solid, and does not
resemble that of the Carchariidae in structure — an important
observation, because a tooth of nearly similar outward form from
the Tertiary of New Zealand is determined by Jaekel,t on
histological evidence, to belong to Hemigakus^ a genus of
Carchariids.

Family CESTRACIONTID^.

Genus Cestracion.

The Port Jackson shark is already known to have survived
in the northern hemisphere until the Middle Eocene period, by

• J. Leidy, Joum. Acad. Nat. Set, Philad, [2I. vol. viii (1877X P- aS'. PL XXXIV,
Figs. 25—30.

t O. Jaekel, <»/. ciV., p. 167, Fig. 30.

TEETH OF SHARKS AND SKATES FROM ENGLISH EOCENE. 7

the discovery of teeth in the Bruxellian Formation of Belgium.*
In England, however, the writer has only identified two
Cestraciont teeth from the Eocene, and both these from the base
of the series. The first specimen (PL I, Fig. 9) was discovered by
Mr. Wetherell in the London Clay at Highgate Archway. It is
a lateral tooth, characterised by a prominent longitudinal crest
and obtusely angulated extremities ; it is rather larger than the
Bruxellian form, and must remain for the present without specific
determination. The second specimen, also in the British
Museum (No. P. 4104^), is a still larger tooth incomplete at one
end, obtained by Mr. Sydney C. Cockerell in the Lower Eocene
of Chislehurst Its rugose crown is gently rounded, not ridged
or keeled.

Family LAMNID^.

The teeth of this comparatively modern family are all solid
when completely formed, and those of the principal genera are
relatively large, more oi less compressed, lanceolate, and pointed,
adapted for lacerating, At least four, perhaps five, genera are
represented in the Eocene ; and, so far as can be judged from
teeth and vertebrae, the four still survive in existing seas.

Genus Odontaspis.

In this genus all except a few hindermost teeth exhibit a
high, narrow, compressed crown, flanked by one or two pairs of
small pointed denticles. The anterior teeth are especially high-
crowned, comparatively large and slender, with a much-produced
bifurcated root. At least four species are known from the
English Eocene.

1. Odontaspis rutoti^ Winkler sp. (PI. I, Figs. 10, 11). The
teeth thus named denote a comparatively small species, known
only from the base of the Eocene. In England they have been
found by Mr. Sydney C. Cockerell in the Thanet Sands at the
Reculvers, Kent. The dental crown is robust, with smooth,
inner face, and the outer base-line not straight but excavated by
a slight re-entering angle. Two pairs of pointed lateral denticles
are usually present, the outer being insignificant. These teeth
are known from the Heersian, Landenian, and Ypresian beds of
Belgium, and are of special interest as being almost identical
with the teeth named Odontaspis bronni from the uppermost
Cretaceous of Holland and Belgium.

2. Odontaspis ciispidata^ Agassiz sp. (PI. I, Figs. 12 — 14). The
teeth of this form, which occur throughout the English Eocene
deposits from the Thanet Sands upwards, were originally named
Lamna (Odontaspis) hopei by Agassiz ; but a study of the large

• Cesh^acion duhonti, T.C. Winkler, Archiv, Mus. Teyier, vol. iv (1876), p. 17, PI. II,
Figs. 1—3 ; A. S. Woodward, Geol, Mag, [3], vol. viii (1891), p. 105, PI. Ill, Fig. x.

8 A. SMITH WOODWARD ON THE

collection in the British Museum shows that they cannot be dis-
tinguished from those of the Continental Lower Miocene pre-
viously described by Agassiz as Lamna cuspidata. The anterior
teeth, though much elevated and narrow, are moderately stout ;
the long crown is only slightly curved, and its convex inner face
is quite smooth. There is a single pair of very small lateral
denticles — sometimes mere rudimentary prickles ; and the nutritive
foramen on the prominent inner side of the root is placed in a
deep cleft (Fig. 13). The lateral teeth (Fig. 14) differ from these
precisely as they do in the existing Odontaspis^ and there need be
little hesitation in referring the species to the latter genus. A few
interesting new facts concerning the dentition are furnished by the
fragment of jaws from the London Clay of Sheppey shown of the
natural size in Fig. 12. The specimen is a lump of indurated clay
displaying the anterior or symphysial end of both jaws, with the
teeth slighdy displaced and obscured. The foremost teeth of the
right side of the lower jaw (md.) are best seen. The first tooth (I) is
not smaller than the second (II), but it exhibits a somewhat
narrower crown than the latter, with the sharp lateral edges not
extending quite to the rounded base, and the lateral denticles
extremely minute. In No. II larger lateral denticles are associated
with the broader crown. The third tooth (III) has lateral
denticles resembling those of No. II, and the crown seems to be
slightly smaller and less elevated ; but the matrix partly obscures
the fossil. Portions of successors of each of these teeth project
from the matrix. Below the next similar tooth (IV) there is
displaced a diminutive tooth (x\ pointing downwards, which
probably occupied the gap between the third and fourth
large upper teeth always observable in Odontaspis, This small
tooth {x) is here noteworthy for its short, broad crown and
relatively large, broad lateral denticles. In the fourth tooth
(IV) of the mandible the slender lateral denticles are still more
conspicuous than in the others, and, so far as can be judged
from its exposed basal portion, the crown seems to be less
elevated. The teeth of the upper jaw («) are unfortunately
shown only by the roots, and thus cannot be satisfactorily
examined.

3. Odontaspis ^/<^a«j, Agassiz sp. (PI. I, Figs. 15 — 18). The
name Lamna elegans is commonly given to every Odontaspis-XWit
tooth from the Eocene formations which exhibits longitudinal
striations on the inner or convex face of the crown. The latest^
researches, however, seem to the present writer to suggest that
two species of Odontaspis are confounded under this familiar
denomination. In the British Museum Catalogue (Pt. I, p. 362)
it was remarked : " Among the specimens originally assigned to
this species by Agassiz are three teeth (op, cit.j PL XXXV, Figs.
6, 7 ; PI. XXXVIIa, Fig. 58) which appear to be truly referable
to Lamna {Otodus) macrota.*' Quite lately, after a study of new

TEETH OF SHARKS AND SKATES FROM ENGLISH EOCENE. 9

specimens from the Lower Tertiaries of Russia, Dr. Jaekel* has
adopted the still bolder course of referring the so-called Otodus
macrotus of Agassiz to Odontaspis^ observing that its front teeth
•*were somewhat later described as Lamna eiegans** {loc. cit^
p. 30). A careful re-consideration of the whole subject seems to
show that this course will prove correct. Probably all the teeth
figured by Agassiz under the name of Lamna eiegans, on Plates
XXXV and XXXVII^j of his volume already cited, are the front
teeth of the shark which must henceforth be known as Odontaspis
macrota. One tooth, however, similarly named by Agassiz (torn,
cit, p. 369, PI. XL^, Fig. 24) from the London Clay of Sheppey,
appears to be much too slender for reference to the latter species ;
and as this is of a type universally termed elegans^ it will cause
least confusion in nomenclature to retain the name for such teeth.
This is the sense in which it is adopted by Noctling in an elaborate
memoir on Selachian remains from the Upper Eocene of North
Germany,t in which the author attempts to identify teeth from
different parts of the jaw. The anterior teeth (Figs. 15-17^
according to this arrangement, exhibit a very high and narrow
crown, only slightly curved, with the inner face strongly striated
longitudinally, and scarcely flattened in the middle. They bear
a single pair of small, prickle-like lateral denticles, and the
nutritive foramen on the prominent inner side of the root is
placed in a deep cleft. The lateral teeth (Fig. 18) have an
almost equally slender, but less elevated, crown, which is similarly
striated and flanked with relatively large, slender denticles.
While the lateral teeth are thus readily distinguished from those
of O. macrota, the anterior teeth cannot always be separated ; and
in some cases the naming of the specimens will be entirely un-
certain. The narrowness of the crown and the intensity of the
striation of the inner face must be regarded as specially
characterising the front teeth of O, elegans, which also seems to
have been a smaller species than O, macrota,

4. Odontaspis macrota, Agassiz sp. (Plate I, Figs. 19, 20). The
typical lateral teeth of this species (Fig. 20) are much compressed,
the crown with sharp cutting edges and a faintly-striated inner
face ; they bear a single pair of *• broad-ear "-shaped large lateral
denticles, which are usually rounded, though sometimes obtusely
pointed — a feature referred to in the specific name. The front
teeth (Fig. 19) are also much compressed, and the striae on the
inner face of the crown are fainter, more wavy and interrupted
than those of the smaller, stouter teeth to which it is proposed to
restrict the name O, elegans. It is still uncertain whether this
species occurs in the London Clay, labels in collections being not
always reliable ; but it is a characteristic fossil of the Bracklesham

• O. Jackel, " Unter-TertUlre Selachier aus Sudrussland," M^tn. Comiti Gfologiquty
St, PtUrUmrgy vol. ix, No. 4 (1895).

t F. Noetling, Abk, Gtol, Sptcialk, Prtussen u, Thiiring. Staaten, vol. vi, Pt. 3
<iB85). p. 61, PI. IV.

lO A. SMITH WOODWARD ON THE

Beds and Barton Clay, and one tooth is recorded from the
Bagshot Beds of Colesworth, near Woking. The type specimens
were obtained from the Calcaire Grossier of the Paris Basin.

Genus Lamna.

If Lamna macrota be removed to Odontaspis^ the only teeth
from the English Eocene which still seem to be undoubtedly
referable to Lamna^ are certain small forms from the London
Clay, Bracklesham Beds, and Barton Clay, which are identifiable
with the so-called Otodus vincenti of Winkler from the Bruxellian
Beds of Belgium. At least, in the deposits where they occur
both in this country and in Belgium, it is not yet possible to
recognise any OdontaspisAWut teeth which might be assigned to
the symphysis of the same jaw. They are much compressed
(Figs. 21, 22), the crown very acute, with sharp edges, and smooth
inner face ; and they bear a single pair of broad, well-separated,
acuminate lateral denticles, flanked in the side teeth by a minute
outer pair.

Genus Otodus.

The name Otodus was given by Agassiz to numerous teeth,
which are now readily recognised as belonging either to
Odontaspis or to Lamna, The very robust teeth commonly
ascribed to the first-described or type species, however, have so
peculiar an aspect that the generic name may well be retained for
these until the fishes to which they belong are known. The
latest researches suggest that they truly represent two forms.

1 . Otodus obliquusy Agassiz. These very stout teeth attain a
large size, the crown sometimes being five centimetres in height ;
and a good series from different parts of the mouth is figured by
Agassiz. The crown is moderately compressed and always
sharply pointed, smooth on its convex inner face, and without
folds at the base. There is a single pair of broad, bluntly-pointed
lateral denticles, frequently showing a tendency to sub-division.
The inner face of the root is prominent, and the nutritive
foramen is not sunk in a groove. Except that the edges of the
crown are never distinctly serrated, these teeth closely resemble
those of certain species of Carcharodon^ and Noetling has actually
proposed to refer them to the latter genus. They are commonest
in the London Clay, but also occur in the Bracklesham Beds and
Barton Clay.

2. Otodus tngonaitSy Jaekel sp. (PI. I, Figs. 23, 24). It has
hitherto been the custom in England to refer the small teeth of
the forms represented in PL I, Figs. 23, 24, to young individuals
of O, obliquusJ^ Dr. Jaekel, however, has lately separated certain
Russian teeth of the same character and proportions under the

• See F. Dixon, "Geology and Fossils of Sussex," PI. X, Figs. 33, 34.

TEETH OF SHARKS AND SKATES FROM ENGLISH EOCENE. II

new name, Hypotodus trigonalisJ^ They are of much smaller
size than those of O. obliquus, and the lateral denticles are less
developed, being merely a pair of small, slender cusps, usually
flanked again by a pair of minute points. The inner face of the
crown is smooth, and the nutritive foramen of the root is placed
in a shallow groove. These teeth have the same geological range
as those of O. obliquus ; but as there are no known teeth distinctly
intermediate between the two forms, it seems likely that they
belong to a distinct and smaller species. No sufficient reason,
however, has been mentioned for placing them in another genus,
and they may, therefore, be known as Otodus trigonalis.

Genus Oxyrhina.

Considering the abundance of the teeth of Oxyrhina in the
Cretaceous, Miocene, and Pliocene formations, it is curious that
they are scarcely known in the Eocene. The present writer is
only acquainted with the two diminutive English specimens
represented in PI. I., Figs. 25, 26. These were originally
described as the type specimens of Carcharias {Scoliodon)
eocanus\ ; but one of them has lately been sliced in a vertical
direction to display the internal structure, which definitely places
it in the family Lamnidae. The teeth being compressed, with
smooth edges, and no lateral denticles, fall within the genus
Oxyrhina, and must be provisionally known as O, eoccena. They
are evidently referable to the side of the upper jaw, and are quite
distinct from the equally small but comparatively slender teeth of
the same genus from the Eocene of Belgium, named 0» nova,
Winkler, and O. winkkri, Vincent.

Genus Carcharodon.

The teeth of Carcharodon resemble those of Oxyrhina and
also of the so-called Otodus, except that the edge of the com-
pressed crown is serrated. There are thus some forms without
lateral denticles, others with a single pair.

1. Carcharodon subserraius, Agassiz. Only one tooth of this
genus without lateral denticles, has hitherto been found in the
Eocene. It was obtained from the London Clay of Sheppey, and
described by Agassiz under the name of C subserratus. It is a
much compressed toothy the crown measuring 0025 m. in height,
and o'02i m. across the base, with very feeble and irregular
serrations. Its root is partially corroded and destroyed.

2. Carcharodon auriculatus^ Blainville sp., var. ioIiapiaiS,
Agassiz. The Eocene teeth of Carcharodon with lateral
denticles, are also of comparatively small size, and at first sight
they are distinctly suggestive of the so-called Otodus obliquus,

• O. Jaekel, op. cit., 1895, p. 32, PI. I, Firs. 6, 7.

t A. S. Woodward, - Catal. Yoa, Fishes B.M.," Pt. I. (1889X p. 436-

12 A. SMITH WOODWARD ON THE

only difTering in the presence of serrations. There seems, how-
ever, to be every gradation between these teeth and the
comparatively large teeth of the Miocene and Pliocene named
. C auriculatus or C angustidens. They must therefore be re-
garded as merely a diminutive, early variety of the latter. One
tooth, said to have been obtained from the London Clay, was
described by Agassiz, under the name of C toliapicus \ and some
from the Bracklesham Beds were identified by Dixon with the
so-called C heierodon^ Agassiz, which is evidently synonymous.

Family CARCHARIID^.

The Carchariidae are almost, if not exclusively, a Tertiary
family of predaceous sharks, with the teeth much resembling
those of the Lamnidae, but differing in their internal structure.
These teeth are hollow throughout life, and minute tubules
radiate from the central cavity across the dentine.

Many existing genera are recognised, but most of them can
scarcely be distinguished on the evidence of detached teeth. The
shape of the teeth, indeed, is much less distinctive of the
various genera even than in the Lamnidae. Several English
Eocene specimens in the British Museum seem to represent some
of the sub-genera of Carcharias, and one tooth from the London
Clay, named Giyphis hastaiis by Agassiz, may belong to the same
genus ; but Gaieus and Galeocerdo seem to be the only forms
recognisable with tolerable certainty. The complete fishes known
from the Upper Eocene of Monte Bolca, are more or less closely
related to the latter genera.

Genus Gaieus.

The small compressed teeth of this genus are known both
from the London Clay (PI. I, Fig. 28) and from the Barton Clay
(Fig. 27), and are almost identical with those of the existing
G. cams. The crown is not serrated, its apex is turned back-
wards, and below the notch in its posterior margin there are a few
denticulations. The so-called Galeocerdo minor^ Agassiz (PI. I,
Figs. 29, 30), from the London Clay and Barton Clay may also
perhaps belong to this genus. The teeth thus named exhibit
denticulations at the base of the crown, both in front and behind
— a condition observable in certain teeth of the existing species
already mentioned.

Genus Galeocerdo.

The teeth of Galeocerdo are serrated on both margins, with a
deep notch in the posterior margin, and the apex more or less
sharply inclined backwards. They are almost similar in both
jaws, and vary very little in different parts. Characteristic
examples of one species, G, latidens^ Agassiz, occur in the
Bracklesham Beds (PI. I, Figs. 31, 32). These teeth are re-
markably low and broad, with very prominent serrations.

or SHAKKS AXD SKATIS FROM ENGLISH EOCKMK. I3

It win be caaweEdcat, in coodusion, to append a list of the
; of Srtarhian teeth now recognised in the English Eocene
jptuiiitiniKV with a statement of their known range. There is
moch still to be learned on the btter subject, and careful collect-
ing bf strat^^aphkal geologists, familiar with the deposits, is
perhaps the next most d^irable mode of research for the
advancement of oor knowledge of the fishes to which the teeth
bdoog.

ALPHABETICAL LIST OF ENGLISH EOCENE SELACHU \YITH
KNOWN STRATIGRAPHICAL RANGE.

AnneHat arftgmsts^ WinkL sp,
AttoSmtis irrtgidartSy Ag.
mtargmalis^ Ag.
CtTckariiM {Giyfkis) Jf^ra/Hs, Ag.
CarcJkgrgJom mmricmJtUus, Blv. sp

var. i9&a^9CMS, Ag.
Carcjkaroi/om smAsrrra/MS^ Ag
CiStr0iu,M, sp.
GaU9C*rd9 iatidtns, Ag.

(?) mm<fr^\\g,
GaUus, sp. .

Zamma rrmcnUi, Winkl. sp.
Myltoh^tis dtxcm^ Ag. .

gfmwpitumt, Ag.
tahdens. A.S.W.
striatum ^ Buck I.
,. toltapicuSs Ag.
Sotidanus prrmntnius^ Ag.

,, serrtttissimus^ Ai:
Odontasph cuspidata^ .Ag.
„ eltgans, Ag. sp.

., macTotm^ .Ag. sp.

rutoti^ Winkl. sp,
Oiodus obliquu%^ .Ag.

„ trigonalis, Jaek. sp.
Oxyrkina eoama^ .A.S.^^ .
Pristis bisulcatay Ag. .
,, contorta^ Dixon
Rhinapttra davust\ :\ S.W.
Squatina sp.
'' A'ipAodo/amia " sp. ,

...

X
X

X
X
X

' X

X
X

1 ^

...

' X

1 ^-^ '

1 ...

' X

, X

X
X

: X

...

EXPLANATION OF PL.ATK I.

Figs. I, 2. — Acanthias orpUnsis (Winkler) ; two teeth from outer aiul
inner aspect respectively. — Woolwich and Rcatling Beds ;
Chislehurst. [P. 4104.]

Fig. 3. — Squatina sp. ; tooth, inner aspect. — IbiL [P. 4i04<i.]

14 A. SMITH WOODWARD ON TEETH OF SHARKS AND SKATES.

Figs. 4, $. — Sguatina sp. ; two teeth, outer aspect. — London Clay ;

Highgate Archway. [43135]
Fig. 6. — Notidanus sirrattssimus^ Ag. ; upper tooth, inner aspect. —

London Clay ; Kensal Green. [43142.]
Fig. 7. — Ditto ; lower tooth, outer aspect. — London Clay ; Sheppey.

[Mus. Practical Geology, No. 6474.]
Figs. 8, 8a, 8.5. — Xiphodolamia sp. (supposed anterior upper tooth of

Notidanus) ; side view, oblique outer view, and lower aspect of

base. — Ilnd, [4314X.]
Fig. 9. — Ctstracian sp. ; tooth, coronal aspect. — London Clay ; Highgate

Archway. [43136.]
Figs. 10, 11. — Odontaspis rutoti (V^'inVXtr) \ anterior and lateral teeth,

outer and inner aspect respectively. — Thanet Sands ; Reculvers.

[P. 4102.]
Fig. 12. — OdoHtaspis cuspidata^ Ag. ; anterior end of jaws with teeth,

outer aspect — London Clay ; Sheppey. md.^ mandible ;

», upper teeth ; x, supposeid small upper tooth ; I — IV,

anterior lower teeth. [28763.]
Figs. 13, 13^. — Ditto; anterior tooth, inner and lateral aspects. — Lower

Eocene ; Portsmouth. [P. 5512.]
Fig. 14. — Ditto ; lateral tooth, inner aspect. — Headon Beds ; Headon

Hill, Isle of Wight. [40240.]
Fig, 15. — Odontaspis elegans, Ag. ; anterior tooth, inner aspect. — London

Clay; Highgate. [20205*.]
Fig. 16. — Ditto; anterior tooth, inner aspect. — London Clay ; Sheppey.

[28887.]
Figs, 17, 18. — Ditto; anterior and lateral teeth, inner (abraded) and

outer aspect respectively. — Barton Clay; Hampshire. [40228.]
Figs. 19, iga.—UdoHiaspismacroia^Ag.] anterior tooth, inner and lateral

aspects. — Bracklesham Beds ; Sussex. I 25683.]
Fig. 20. — Ditto ; hiteral tooth, outer aspect. — /W. [25686.],
Fig. 21. — Lamna vimtnti (Winkler) ; tooth, outer aspect. — Barton

Clay ; Hampshire. [40244^.]
Fig. 22. — Ditto ; tooth, inner aspect. — London Clay ; Highgate.

[43132.1
Figs. 23, 23*. — Otodus {Hypotodus) trigonalis (Jaekel) ; anterior tooth,

outer and lateral aspects. — Bracklesham Beds ; Sussex.

[P. 1167.]

Fig. 24. — Ditto ; lateral tooth, outer aspect. — Lower Eocene ; Ports-
mouth Docks. [P. 5506.1

Figs. 25, 26. — Oxyrktna eoccena (A. S. Woodw.) ; two teeth, inner
and outer aspect respectively. — London Clay ; Highgate.

[43135.]
Fig. 27. — GaUus sp. ; tooth, outer aspect. — Barton Clay ; Hampshire.

[40242*.]
Fig. 28. — GaUus sp. ; tooth, inner aspect. — London Clay ; Highgate.

[43I34«.J
Fig. 29 — Gaieocerdo ( f) minor ^ Ag. ; tooth, outer aspect. — Ibid, [43 1 34 J
Fig. 30. — Ditto ; tooth, inner aspect. — Barton Clay ; High Cliff,

Hampshire. [40245.]
Figs. 31, 32. — CiUoardo latidtns^ Ag. ; two teeth, inner and outer

aspect respectively. — Bracklesham Beds ; Sussex. [25677.]

All the figures are of the natural size. Except the original of
Fig. y, all the specimens are preserved in the British Museum,
and bear the Register numbers placed in square brackets.

Proc Geol. Assoc. Vol. XVI

Pi:.

^eendtl ..t nth

^OCEhTE SE

^LACHIAN TEETH

ifii»k«Tik'B««%.i

CONTRIBUTIONS TO THE GEOLOGY OF THE
THAME VALLEY.

By a. M. DAVIES, A.R.C.S., B.Sc., F.G.S.

(Read December and^ 1898, *)

[PLATE II.]

I.— INTRODUCTION.

THE Thame is, broadly considered, a longitudinal or " sub-
sequent " tributary of the Thames, draining the region at
the foot of the Chalk escarpment of the Chilterns. The area
drained by it is roughly an oblong, about twenty-five miles in
length from N.E. to S.W., in the general direction of the strike of
the strata, and varying from ten to twelve miles in breadth from
N.W. to S.E., or in the general direction of dip. Its south-eastern
boundary is the crest of the escarpment of the Chilterns, which
maintains a steady height of from 700 to 800 feet above sea-level,
except where beheaded valleys reduce it to nearly 400 at
Saunderton, Wendover, and Tring, Its north-eastern boundary
runs in an irregular manner from near Tring to Stewkley, and does
not rise much above or fall much below 400 at any point. The
north-western boundary is much more irregular, both in direction
and in level, rising to over 600 at Quainton, Brill, and Muswell
Hills, and over 400 in the high ground about Wheatley, and fall-
ing to about 250 in the low areas that alternate with the hills.
(See fig. i).

The region thus defined geographically is no less clearly
marked geologically. It is sharply distinguished by a double
peculiarity in geological structure from the adjoining areas on
the same line of strike. The first difference is that the sandy
beds below the Gault, commonly termed '* Lower Greensand,"
have a broken and irregular outcrop. The second is the presence
of higher Jurassic beds — beds, moreover, of sandy and calcareous,
instead of the predominant clayey, character. The abundance of
outliers may be said to constitute a third distinction.

The course of the Thame itself is interesting. It flows over
clay ground for practically its whole course, some of its head-
waters and its final fiv^ miles or so being on Gault, while the whole
intervening portion is on Upper Jurassic (Kimeridge) Clay.
Between the points at which it leaves and re-enters the Gault
area, the stream falls just 100 feet — from about 270 to about
170 feet above O.D. At both these points the two clays are
either in direct superposition or have only a small thickness of

* Some !(Ught additions have since been made, and certain parts omitted.

February, 1899.]

A. M. DAVIES ON

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THE GEOLOGY OF THE THAME VALLEY. 1 7

intervening beds ; whereas elsewhere in the district more than loo
feet of other strata intervene. Thus the geological structure of the
district has modified the course of the Thame from that of a
simple subsequent stream to a more complex form, to which I
shall refer towards the end of the paper. The irregularity of the
north-western watershed — unusual in a strike-boundary — is due to
the same causes.

Although described by Buckland and Conybeare, and mapped
by William Smith, the district first underwent a thorough
examination by Fitton, whose observations are recorded in the
classical memoir, "On the Strata between the Chalk and the
Oxford Oolite" {Trans. Geo/. Soc., ser: 2, vol. iv, p. 163). Twenty
years or more after Fitton, the Geological Survey examined and
mapped the district^ and their results appear on Sheets 13,
45 S.E. and 46 S.W., published in i860, 1863, and 1865 respec-
tively, and in the explanatory memoirs to the first two of these
sheets, pubh'shed in 1864 and 1861.

About the same period Prof. Phillips made a number of
observations on the district, which are recorded in his " Geology
of Oxford"

The chief railways in the Tham'^ Valley were made very
shortly after the completion of the Geological Survey — a fact
much to be regretted, since the cuttings, though shallow, are
numerous, and would have given valuable information had they
been properly studied. Now they are all grass-covered, and I
have only been able to discover geological references to two, other
than those at Aylesbury (Codrington. Quart Journ. GeoL Soc,
vol. XX, p. 374; Cobbold, idid, vol. xxvi, p. 314).

During the next twenty years the district was chiefly studied
by Prof. Morris, Mr. Hudleston, and Prof. Blake, each of whom
has guided excursions of this Association to the district.'*'

More recently some revision of the area has been made by
Messrs. A C G. Cameron, J. H. Blake and Jukes-Browne, for
the Geological Survey, but the results are as yet only partially
given to the public. Some observations on the Upper Jurassic
rocks have, however, been made by Mr. H. B. Woodward, and
are to be found in the Memoir on these rocks (Vol. V.), but the
only account of the "Lower Greensand" is in the "Explanation of
Horizontal Section Sheet 140," by Mr. Jukes-Browne. Con-
siderable revision of the boundary lines seems, however, to have
been made in the north-eastern part of the aiea, judging from the
new Index Map.

The present paper records a series of observations made
during the last two years in a number of visits to the district, and
the conclusions based upon them. My original intention was to
study a small part of the area only in greater detail, but the
necessity of comparison soon led me over almost the whole

* See Ruord^ Excmrsi^Ht ; and Pf§c, Gtcl, Assoc., vol. xiii, p. 71.

February, 1899.] 2

1 8 A. M. DAVIES ON

area. To map so large a district in detail would require years
from a private worker who can only spare a few days now and
then for the task. I have, therefore, attempted nothing so
ambitious. Confining myself, for the most part, to the beds
between the Kimeridge Clay and the Gault, I have repeatedly
visited the outcrop and chief outliers of these beds, traversing
them in many directions. I do not think I can have overlooked
any important exposure, unless it be on certain outliers which I
have not had time to visit I have examined many of the rocks,
microscopically and otherwise, at home.

In field-work, I heed hardly say that I have derived the
greatest possible assistance from the published maps of the
Geological Survey. Although the existence of new exposures
has in some cases enabled me to detect errors in the mapping, I
am able to testify to their very great accuracy on the whole,
especially in view of the fact that the area was surveyed before
the six-inch maps were available.

I have to express my special thanks to Mr. J. H. Blake,
who conducted me over the classical section of Shotover Hill ;
to Messrs. E. T. Newton and H. A. Allen of Jermyn Street
Museum, and Messrs. R. B. Newton and G. C. Crick of the
Natural History Museum, for great help in the identification of
fossils ; to Mr. F. Chapman, who has identified and supplied
notes on all the Ostracoda and Foraminifera ; to Prof.
Bonney, who kindly enabled me to examine the late Prof.
Morris's specimens at University College ; and to my wife, who
has drawn the maps and sections, and helped me in the field-
work.

IL— PORTLAND BEDS.

The Portland Beds, or such part of them as is lithologically
separable from the great clay-formation below, were divided by
the Geological Survey into " Portland Sand " below, and " Port-
land Stone " above. This division does express the fact that on
the whole sands predominate in the lower part and limestone in
the upper; but Mr. Whitaker has referred to the difficulty in
separating the two at many points. Mr. H. B. Woodward has
shown that these two divisions here do not correspond in age
with those so-named in Dorset. In fact, it is probable that the
line between them, even where it can be satisfactorily drawn, does
not represent a constant horizon throughout our district.

Similarly, the base-line of the " Portland Sands " does not
represent a constant horizon, but as it is a very definite strati-
graphical line, marked by a line of springs, I shall speak of the
beds above it as the " lithological Portland,'' to avoid misunder-
standing and needless complexity of phrasing.

THE GEOLOGY OF THE THAME VALLEY. 1 9

Prof. J. F. Blake, in his paper on the " Portland Rocks of
England" {Quart. Journ, Geol, Soc.^ vol. xxxvi, p. 189)
distinguished within the " Portland Stone " of this district an
upper " Creamy Limestone " and a lower " Rubbly Limestone,"
separated by a bed of sand. These divisions hold for tne north-
eastern part of the district, but I have not been able to recognise
them in the central and south-western portions.

There are only three places in the district where I have found
it possible to obtain a tolerably complete section down to the
top of the clay series, namely, Garsington, Long Crendon, and
Dadbrook Hill (between Haddenham and Cuddington). A fourth
section, that of Stone and Hartwell, has been already determined
by Messrs. Hudleston, Blake, and H. B. Woodward. These
four sections are indicated in Plate II, and it will be convenient
to consider the Portland Beds in each of them before going on to
a general description.

(a) Garsington Section.

When Dr. Fitton visited the district there seem to have been
many stone-pits here, since he says that the principal ones are in
the western escarpment of the hill, overlooking the low ground
about Langcomb and Cowley. Now, however, the stone-pits
seem all abandoned and mostly levelled over ; the only one I
saw was being used to store Leicestershire road-metal. Still, a
number of small roadside exposures are available, and with the
help of the six-inch map and a reflecting level I have been able
to piece together a tolerably complete section.

The lowest beds are best exposed in the cuttings of the
Oxford road as it mounts the hill from Kiln Farm into Garsington
village. Clay is seen exposed at intervals almost up to the little
stone-quarry mentioned above, which must expose almost the
very base of the lithological Portland. The presence of a series
of springs at about 340 feet above O.D. marks this as the level of
the top of the clays. In the quarry itself there are exposed :

ft. in.

3. Pale bluish-green and grey sands 9

2. Shelly sands passing down into sandy limestone ... i o

I. More massive limestone 3 6

There seems to be a rapid lateral change in Bed 2, but it is
not easy to trace it. Above the level of the quarry and farther
back from the road, a fine vertical face of pale yellowish sand
about 1 5 feet high is exposed. Thus here we have " Portland
Stone " at the very base of the ** Portland Sand." The pale sand
can be traced in the road-cutting from here nearly up to the " Red
Lion," and two courses of stone occur in it, as shown in the
section (Plate II). From this point the succession failed.

20 A. M. DAVIES ON

A more complete section can be made out on the other side
of the hill, less than half a mile away. On the six-inch map a
spring is marked a quarter-mile due south of City Farm. This
fine spring is apparently thrown out by the clay at the base of the
Shotover Ironsands, and in the side of a steep bank. If one
follows the path along the top of this bank and down the hill-
slope beyond, a trench is seen to run straight alongside the field-
boundary. This trench had only been dug quite recently when I
visited the spot last November, and clearly exposed the beds for
a thickness of about 60 feet on both sides of the little valley, and
although neither top nor bottom of the lithological Portland is
shown, the position of these can be judged from surface indica-
tions. The Portland Sand is seen to a thickness of about 35 feet ;
towards the base it becomes clayey, and the basal limestone of the
previous section seems to be absent. The sand is topped by a
pebble-bed a few inches thick, full of pebbles of various shapes and
sizes, but all well-rounded, and mostly between J-inch and i^
inches in length. Some of these are of quartz, but the majority are
of black material, which one is apt to dismiss as " jydite." Careful
examination, however, shows the latter name to cover a variety
of materials ; most of them are black chert, but among them I
found several pebbles of spherulitic felsite and one of phosphatised
bone.

Immediately above the pebble-bed, limestone begins and
continues for about 12 feet; the basal part is very glauconitic
and pebbly, and casts of Cardium dissimiU are seen. Above
come 9 feet of sand again, with one thin course of stone. After
this the section becomes obscure, but there is evidence of more
limestone, and then of the Shotover Ironsands at the top.

The Garsington section in Plate II was drawn up (so far as
the Portland beds are concerned) from these two sections in com-
bination, the details of the lowest 25 feet above the clay being
taken from the road-section on the west of the village, and the
remainder from the trench-section. The complete section is
therefore a generalised one.

(b) Long Crendon Section.

Long Crendon is eight miles from Garsington, nearly along
the line of strike. For six of those miles no Portland beds are
exposed. Here again the section is pieced together from the
exposures along several roads down the hill-side, but we have in
addition a number of sand and stone pits and a brickfield. The
last is at the foot of the hill by the side of the road to Thame,
and was visited — or, at least, noticed — by the Association under
Prof. Blake's guidance, in 1893. P^f. Blake then referred to the
clay in the brickyard as Hartwell Clay, and it is also so referred

THE GEOLOGY OF THE THAME VALLEY. 21

to by Mr. H. B. Woodward in his memoir, but I am not aware
that Hartwell fossils have been found in it. I have found none,
and a workman I spoke to said that none were found, though he
certainly knew what fossils were. Its top is marked by a line of
springs, the Lion Spring near the brick-kiln being one, at 272 feet
above O.D., while another in Sandy Lane, a little over half a mile
to the north-west, is rather above the 300 ft. contour.

The lowest bed of the lithological Portland, resting directly on
the clay, is a bright green sand.

The upward sequence may be traced with tolerable complete-
ness on the ascent from the Lion Spring to the village, and con-
firmed in Sandy Lane. We find some 30 feet of light-coloured
sandy beds, in which there occur several beds of clayey sand.
The lowest 1 1 feet or so is not exposed (except for the green sand
above mentioned), but above this 5 feet of clayey sands are
shown in a pit in Sandy Lane, and the presence of the same in the
main road above the Lion Spring seemed to be shown by the
presence of water at the bottom of a sand-pit there. In both
sand-pits we next find the characteristic pale sands of the Portland,
with a few lydite pebbles here and there, and with much clayey
material in some beds ; and in the pit by the main road we see,
near the top, a laminated clayey sand full of lydite pebbles. This
agrees closely in position with the pebble-bed of Garsington.

Continuing up the main road above the sand-pit, the road
cutting shows a great amount of limestone, with indications of
intercalated sand-beds here and there. At the point marked
" Kiln " on the six-inch map, there is a small section as follows :

Section at "The Kiln," on the Ascent to Long Crendon
FROM the Lion Spring.

ft. in.

5. Soil I 6

4. Thin-bedded limestone o 4

3. Calcareous loam o 6

2. Rubbly limestone about 5 o

Another section a few yards to the north shows below the

rubbly limestone :•—
I. Massive limestone with" -<4»im.^^a«/^wy,"* Trigonia^ Car-

dium^ etc 10 o

Through the village of Long Crendon itself the ground is
comparatively level, and though there are occasional exposures,
the sequence cannot be followed. When we reach the more
southern of the two windmills, a valuable section of the top beds
is exposed, and allowing for the slight dip, it seems probable that
only 5 or 6 feet intervene between the highest beds seen in the
last section and the lowest seen in this one.

* The large amsonites commonly referred to by this name are probably in all cases in
this district PtritpkincUt bcloniensis^ De Lor. as Prof. Blake bat pointed out.

A. M. DAVIES ON

Section at Southern Windmill, Long Crendon.

Gault.

? Shotover
Ironsands."

Purbeck.
Portland.

ft. in
Clay with Inoceramus concentricus^ Be-

limnitis mmimus and Foraminifera ... 8 o
8. Sand, with pebbles of quartz and lydite, and

irQnstone-concretionscontainingcalcite ... i 6

7. Green sandy clay i 6

6. Ironstone o 6

V 5. Bluish clay, black at base o 6

4. Limestone with clay-veins 4 6

3. Pale clay, with Ostracods i o

2. Crumbly calcareous sandstone o 5

I. Massive blue-hearted limestone 3 6

This pit may be the actual one visited by the Association
under Prof. Blake's guidance in 1893, but I suspect that that
was another one some seventy yards farther west, which has been
closed during the last eighteen months. The two sections differed
only in slight details (mainly in the Shotover Ironsands).

The generalised section pieced together from these exposures
is shown in Plate II. It agrees generally with that given in the
memoir on the Jurassic rocks and that of Fitton, but differs in
some details, due undoubtedly to variations in the strata from
point to point. Thus Fitton found the pebble-bed immediately
below a sandy and glauconitic limestone, and H. B. Woodward
notes a pale-grey and greenish marl with Trigonia gibbosa, etc., as
the top Portland bed, and 3^ feet of calcareous sandstone
within the upper blank space in my section.

The Dad Brook is a small tributary of the Thame, which has
cut a steep-sided valley north of and nearly parallel to the main
Thame- Aylesbury road. The road from Haddenham to Cudding-
ton crosses this main road at a point known as the King's cross-
roads or King's Cross, and then crosses the valley of the Dad Brook
at right angles (see Map, p. 54). The steep slope down from the
plateau on the south side of the valley is called Dadbrook Hill
on the maps ; it lies three miles E.N.E. from Long Crendon. As
it is only a mile N. of the important village of Haddenham, and
almost entirely within the parish of that name, I give that name
to the section.

About 150 yards west of King's Cross, a small quarry has
been opened in a field. I shall describe this section in detail
later on (p. 40) in connection with the Purbeck beds, of which
some 9 feet or more are exposed, with 3 or 4 feet of Portland
Limestone below. In July, 1898, the ditch alongside the steepest
part of the road down Dadbrook Hill had been freshly trenched,

XBES i^SOLOGT OF THX TSaMX VALLKY.

a-.

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z

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tt^

fi ^

^ -51
1 ^^

I *-

1 *^

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- — 5

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11 =

1:5 1

.2 S So

I lii

azid m it beds of lime^
stooe, sawi ami da^
wore cfeflirty expooei By
miQtos of tbese two $ec^
ttQQsand'^
exposures mi
side o£thc v4ilc> uod el^^c-
where^ t n^ %blK to plot
out ;uc section ar - the
\^Uey (Fig. II auid the
vcrticat !^xnton i Plate U).

The clay at the ba$e
is somewhat j^axxdy and
mkaceous ; I have found
no fossils in it At its
junction with the sand
above» a spring occurs
which seems to have
attained some small fame
^s 4 viirfi>ta*v»v spring'
The [H>int marked ^' l>au-
brook Spring; " o i the six
inch map is. howex-vi*
some twenty v-arUs iwnih
of the setUial jiiacik^n,
and in JicAtt^s ihv |HwiUo!i
of a little brick structurxr
in which the water is
received, l^st Septenv
bet this spring was quite
dry.

At the junction of the
sand and clay some lydite-
l-jcbbles occur, thougli not
very ahuiulir^tly The
sand itself is the usuaI
pale yellow sand, with
occasional glauconitc
grains, so characteristic
of the Toritand beds*
A bed of limestone, o
or II inches thiol:, occurs
in it si feet from the
bisc, and at a height of
15 feet above the Imse,
limestone follows and
apparently continues up
to the base of the little

24 A. M. DAVIES ON

quarry, though the evidence of this is incomplete, and it is quite
possible that some alternations of sand may occur.

(d) Stone and Hartwell Sections.

The remaining section on Plate II is simply a copy of one
already published by Mr. H. B. Woodward, so far as the Portland
and Purbeck Beds are concerned; the Bishopstone Beds are
inserted from my own observations. Mr. Woodward's section
appeared in the Memoir on the Jurassic rocks and has been
repeated in our Proceedings (voL xv, p. 93) as a " General Section
at Aylesbury." The main details, however, are derived from the
Bugle Pit, which is in the parish of Stone, 2 miles S.W. of Ayles-
bury, and 3i miles N. by W. from Dadbrook Hill. The Windmill
Pit, from which most of the details of the Bishopstone Sands are
taken, is also in the parish of Stone, nearly one mile farther west,
and this section lies almost exactly in a straight line from Gars-
ington through Long Crendon and Dadbrook Hill to Aylesbury,
being 2^ miles from the last and 2} miles from the last but one
of these places.

Mr. Woodward's section is fully explained in his memoir, and
more briefly in our Proceedings lately, so that I need not say
more on it here.

To complete this set of vertical sections I should like to have
added a fifth, dealing with the sequence to the north, either on
Quainton Hill or at Oving and Whitchurch. But the information
I have been able to get there is not sufficient to allow me to plot
out a section similar to the other four.

(e) Comparison of the Sections.

In comparing these four sections, the fact which strikes us
first is the great difference in thickness between the Hthological
Portland of Garsington and Long Crendon and that of Dadbrook
Hill and Hartwell. The thickness in the two former cases is
practically double that in the latter. How shall we explain this
sudden change in thickness in the three miles between Long
Crendon and Dadbrook Hill ? In each case we have ** Portland
Sands " below and " Portland Stone" above ; do these Hthological
names mean the same chronologically in the two cases ? If they
do, what is the explanation of this sudden change in thickness in
both formations ?

I do not think that the Hthological divisions mean the same
in the two cases. Mr. H. B. Woodward has called attention to
the occurrence of a pebble-bed or lydite-bed as separating the
Upper Portlandian from the Lower at Tisbury, Swindon, Bourton,
and Brill, as well as at Aylesbury. Now, lydite and quartz-pebbles

THE GEOLOGV OF THE THAMK VALLEY. 25

occur at one levd ODly in each of our four sections, and are quite
restricted in their vertical range. If we take the pebble-bed in
each case as a constant horizon, the difficulty as to the change in
thickness vanishes, the " Portland Stone " of Garsington and Long
Crendoo being represented by the whole of the lithological Port-
land (Stone and Sand) of the easterly sections. Sand, indeed, is
not wantii^ within the limits of the " Portland Stone " at Garsing-
ton. Again, if we consider the Lower Portlandian, or beds below
the pebble-bed, we can trace a gradual transition, the clayey facies
gradually rising from west to east. From the 39 feet of pure
sands with limestone of Garsington, we pass through the 36 feet
of more or less clayey sands of Long Crendon to the sandy clay
of £>adbrook Hill and Hartwell. As a confirmation of this view
we may note that at Scotsgrove Hill, \\ miles S.E. of Long
Crendon and 2^ miles S.W. of Dadbrook Hill, the pebble-bed is
seen with only 12 feet of sand below it, and with both limestone
and sand above it The pebble-bed also seems to have been
noted at Great Hazeley by the Survey officers, at Cuddesden and
Garsington by Prof. Blake, and is well known at Brill and Bierton,
while the pebbly character of the beds in which the " Giant's
marbles " occur on Shotover Hill may perhaps indicate the same
horizon.

Since this paper was read, Mr. J. H. Blake, who has been
ooapping the western part of our district for the Survey, has
kindly informed me of an exposure of a similar pebble-bed on the
eastern slope of Shotover Hill, near the 400 feet contour.

There are certain general reasons why a pebble-bed of this
kind should be a ihore trustworthy indication of a definite horizon
than a line of lithological change. It must be remembered that
this is a solitary bed of coarse material interpolated in the midst
of a series of which the other beds are fine sands (the grai )8
usually being about *i mm. in diameter), limestones, and clay.
Such a bed, especially when continuous over a large area,
betokens most probably an interruption of normal sedimentation
for a time by the action of a current — some of the fine material
previously deposited being probably swept away at the beginning
of the current-phase, while at the end of that phase the first
slackening in the current would cause a deposition of pebbles
previously swept to and fro, and then the deposit of fine material
would be resumed.

At Swindon, and in the Aylesbury district, phosphatised
fossils have been found in the pebble-bed, and I have found one
such fragment at Garsington. These are confirmatory indica-
tions that the pebble-b^ indicates a period of current action
and cessation of sediment

Stratigraphically, therefore, the evidence for the view that the
pebble-bed marks a constant horizon in our district is strong ; but,
to complete the proof, palaeontological evidence is needful. This

26 A. M. DAVIES ON

I am, unfortunately, not able to supply at present. The Hart well
Clay contains an abundant and characteristic fauna, which proves
it to be Lower Portlandian (Middle Portlandian of Continental
geologists) ; but the sands below the pebble-bed at Garsington
and Long Crendon are very unfossiliferous. The only fossils I
found at Garsington were Pleuromya tellina (which ranges from
Corallian to Upper Portlandian) and a cast of a large Cardium,
very close to C. dissimiie. This latter species is characteristic of
the Upper Portland, but does occur in the Lower (according to
the table in the Jurassic Memoir). On the other hand, the Hart-
well Clay species of Cardium are small ones (C. moriniaim and
C. 5triatu!um\ and the large C dissimile is unknown there.
Until a larger collection of fossils has been made from the sands
below the pebble-bed, the question cannot be taken as settled.

(f) General Account.

Let us now trace the outcrop and outliers of the lithological
Portland from S.W. to N.E. through our district.

The westernmost point where Portlandian beds (other than
Hartwell Clay) have been supposed to occur is at Toot Baldon,
one mile S.W. of Garsington. The sands here have been mapped
as Lower Greensand, but Phillips found near their base a pebbly
bed with an Ammonite "of the group of A. polyplocus'' (i.e. a
Perisphinctes), This suggests Portlandian beds, bur it is the only
evidence for them. Exposures here are at present very poor, and
I failed to find any fossils. I shall refer to these sands again
in Part IV.

The undoubted Portland beds begin along a N.W. — S.E. line
about a mile north-east of Toot Baldon. This line marks off the
limit both of the main outcrop and of the large irregular outlier
that forms the heights from Shotover Hill to Garsington, an outlier
separated from the main outcrop by the Thame in cutting down
its present valley.

Shotover-Garsington Outlier. — The Shotover Hill suc-
cession has been fully described by various authors, and I have
nothing lo add to the account in the Survey Memoir on the
Jurassic Rocks. Coming to the south side of the railway, a good
section of the upper part of the Portland was once exposed in
the deep cutting of the road from Horsepath to near Combe
Wood. This is figured and described in the Survey Memoir to
Sheet 13. Though much obscured now, the succession of beds
can still be made out in this section, and in addition to those
figured, the " Portland Sand " can be seen a little lower down the
road. At the foot of the hill sandy clay was exposed in a drain
in connection with a new house being built on the north side of
the road (September, 1898), and I measured the total thickness

THE GEOLOGY OF THE THAME VALLEY. 2J

of the lithological Portland here (by means of a reflecting level)
as about 60 feet.

For a mfle from here southward there are no good exposures,
though signs of the old pits mentioned by Fitton may be detected,
and the next one is in a hollow lane leading down from the main
Wheatley — Garsington Road, south of City Farm, to Kiln Farm.
The first furiong along this lane is level, and the soil in the fields
is that of typical Shotover Ironsands. Then comes a rapid
descent for 150 yards, and in the cuttings can be seen— first,
ironsands ; then a white plastic clay of the Shotover beds, doubt-
less the bed which throws out springs all along the line ; then
more ironsands, of no great thickness. Next comes a fine
calcareous sand with concretionary lumps ; below tiiis is a
calcareous glaucohitic sandstone (or sandy limestone), then
4 inches of rubbly limestone with Trigonia casts, and below that
a soft calcareous sand. From here downwards the section is
much obscured by slip from the Shotover Ironsands, and the
last-mentioned beds had their dip affected by the slip. I cannot
feel sure, therefore, that the sandy limestone seen at two points
a little lower down was really in place.

We now come to Garsington village, where the chief exposures
have already been mentioned. Minor exposures of sand, with
stone-beds, occur at several other points in the village. But in
the road-cutting on the way to the Manor House there is seen a
white clay, slightly calcareous, overlying typical pale yellowish
sand I am unable to place this clay anywhere in the Portland
sequence : possibly it may have slipped here from the Shotover
Beds. I obtained from it a single ostracod, identified by Mr.
Chapman as Metacypris (?) sp, nav.

Followmg the outcrop northwards from the village, we pass
the trench-section already mentioned (p. 20), and half a mile
farther north-west, in a field one-third of a mile almost due south
of the Horsepath Road cutting, we find, a little below the 400
feet contour, the following exposure :

Small Field-exposure on Crest of Hill above '* Lower Barn,"

NEARLY A MiLE N.E. OF GaKSINCTON.

ft. in.
5. Soil with limestone-rubble, indicating a higher limestone

bed near by 07

4. Fine sand o 2

3. Very calcareous sand o 3

2. Buff sand, with very few glauconite grains o 4

I. Hard calcareous sandstone, showing fine layers on weathered

surface, but not fissile ..17

A small digging just below shows pure yellow sands.

In Cuddesden village Portland Limestone crops out in the
roadway ; and less than half a mile north-east of it, alongside the
footpath to "The Park" which runs parallel to the 300 feet
contour, we find the following section :

A. M. DAVIES ON

Small Quarry near 300 Feet Contour, i Milk N.E. of Cuddbsden.

Shotover
Beds (?)

Portland
Beds.

6. Soil and rubble ... about

5. Beds of dark clay and sand, resting on irregu-
larities in the bed below, varying from o to
f 4. Soft rubbly calcareous sandstone,- with abun-
dant casts of Trigonia (the uppermost 18 in.
is in places a birder stone). Perhaps in
part nmanii. Thickness up to

3. Harder, shelly calcareous sandstone (or sandy
limestone) with abundant fossils — Ostrea ...

2. Soft, crumbly calcareous sandstone

I. Hard calcareous sandstone (or sandy lime-
stone)

ft.

6 o

The lower part of the lithological Portland around Cuddesden
seems to consist of rather clayey sands, as though the change that
is seen at Long Crendon were already beginning to show itself;
but there are no good exposures.

Continuing round the outlier, one finds on Castle Hill some
indications of a greater development of the limestones, for in the
ploughed fields about the 300 contour there are abundant fossils
thrown up — Cardium dissimile^ Trigonia^ and a "gigantic"
Ammonite.

We now arrive at the point where, on the Geological Survey
Maps (including the recently-published Index Map, Sheet 11),
the Shotover Beds ("Lower Greensand") are marked as over-
stepping the Portland to rest directly on the Kimeridge Clay. I
am not prepared to assert that no such overstep exists, as I have
not been over the whole ground in question. But at the point
where it is shown as having its greatest extension, between
Wheatley and Littleworth, I have found evidence of both " Port-
land Sand " and " Portland Stone," and I believe the apparent
overstep to be due to extensive slips down the steep hillside.

The railway between Wheatley and the Horsepath tunnel cuts
right through the supposed transgression, but the cutting is now
obscured. Just south of the railway, however, large diggings of
Kimeridge (or Hartwell?) Clay for brick-making have been
made, and these show no sign of the ironsands in place above
them. From the eastern end of the brickfield a footpath which
has crossed the railway on the level leads up to Windmill Lane
through ploughed fields and market-gardens. At first the soil
is sandy, but about the 400 contour it shows such an abundance
of limestone-fragments that it cannot be doubted that there is
an actual outcrop beneath. From among these fragments I picked
up a portion of an Ammonite {Perisphinctes probably bipUx),
The limestone continues nearly to the top of the path, where the
ironsands are seen by the hedge.

Another footpath, more to the west, not marked on the six-
inch map, leads from the hamlet of Littleworth obliquely up the
hill and aifterwards turns along the hillside to join the path just

THE GEOLOGY OF THE THAME VALLEY*. 29

described. Along the lower part of this some instractiTe
openings can be seen. In one there are shown some five feet
of typical pale ^Poitiand Sands" with Urge calcareous con-
cretionary masses, reminding one of those of Shotover Hill ; but
the sand-grains are much finer and the concretions not so hard.
In these Serpula were abundant Above these sands, ironsands
and ironstone were seen ; these may possibly be in situ, but I am
strongly inclined to think that they have slipped down. It is
difficult to fix the position of these exposures on the old one-
inch sheet — the road by Littleworth has been shifted in the mak-
ing of the railway — but it is possible that this is just the point
where the last appearance of '* Poctland Sand " was shown by the
Geological Survey. Certainly there is a profusion of '* Lower
Greensand " material in the soil from here eastwards, but in view
of the limestone outcrop higher up the hillside, the absence of sands
above the clay in the brickfield, and the steepness of the hillside
with its structural suitability for slipping, it seems highly probable
that the supposed overstep has no real existence.* This
practically completes the "beating the bounds" of this large
oudier.

Main Outcrop, Great Milton District. — Through most
of this area the slope of the ground is so gentle and the expo-
sures are so small and scatter^ that it is almost impossible to
piece together the evidence into generalised sections, as I have
been able to do at Garsington and Long Crendon. According to
the published map, the Portland beds appear from under the
overstepping Gault, about half a mile west of Sudhampton, and
range northwards from this point above the left bank of the
Thame to the valley of the small tributary that flows near
Chilworth Farm. Near the source of this brook they are agair
overstepped by the Cretaceous beds. A second narrow outcrop,
due to a strike-fault, extends for some way parallel to the Hazeley
Brook, between it and the village of Great Hazeley. I have not
verified the lower boundary-line, but have no doubt that it is
substantially correct, though the very sandy nature of the material
thrown out of the rabbit-burrows near Cuddesden Mill made me
suspect that the line here should possibly have been drawn nearer
the river. As regards the upper boundary, I think that too great
a spread of " Lower Greensand " has been shown around Great
Hazeley, for there seems to be Portland Limestone exposed in
the roadway in the village, and in the little quarry by the church,
described below, the Hmestone occurs immediately under the soil.

The best exposure of Portland beds in this district is the one
at Great Milton, shown on the six-inch map, and described in the
Memoir on the Jurassic Rocks (Vol. V, p. 219). As there is
no essential variation in the face now exposed from that described

* At the meeting wbcn this p«per was read, Mr. H. B. Woodward announced that Mr.
J. H. Blake had detected and corrected the error in the mapping here in 1897.

3© A. M. DAVIES ON

there, I need not insert a description here, though I shall have to
refer to this pit again in connection with the. "Lower Greensand."
I have not been able, however, to verify the presence of chert in
the sandy oolitic limestone here. There are certain concretionary-
looking masses of darker colour in the rock, but they are cal-
careous ; in fact, they are much purer limestone than the main
rock, leaving only a slight residue of clayey material and very fine
sand-grains when dissolved in acid.

A mile south-west of this exposure, near Little Milton
village, a hundred and thirty yards along the main road south-
west from the milestone marking sixteen miles from Aylesbury, a
small opening exposes a thickness of 15 feet, now much obscured
by slip and partly grassed over. All that can now be made out is
about a foot of rubbly oolitic limestone, beneath 2 feet 6 inches
of loamy soil. Fifty yards off, towards the footpath to Great
Hazeley, a small digging on a level with the bottom of this pit
shows the typical pale yellow sands which extend from here, so
far as the soil indicates, about half way to Great Hazeley.

Great Hazeley was at one time famous for its stone. Phillips
speaks of it as having been quarried from ancient time, and some
of Fitton's best sections were obtained here. Now the abandoned
quarries, several acres in extent, speak forcibly of the economic
changes of this century. The only quarry which had evidently
been worked recently was a small one in a field near the church,
at the eastern end of the village, where the section is as follows :

Small Stone-Pit near the Church, Great Hazelev.

ft. in.
5. Rubbly white limestone with many casts of small shells,

passing up into soil 2 6

4. Thin-bedded, crumbly, calcareous and glauconitic sands.

about 3 o

3. Black-spotted (not glauconitic) sandy limestone, with casts

of Trigonta^ etc., passing down in about a foot into

calcareous sand with shells (Ostrea^ Pecten) in places,

which passes locally into hard, slightly glauconitic

sandy limestone 4 o

2. Soft, coarser, brownish sand about i 3

I. Hard, sandy limestone over i o

Bed 3 projects as a ledge over 2, which is damp and mossy.

The only other exposure of interest that I have seen in this
district owes that interest chiefly to historical reasons. This is
one in a field near Peg's Farm, i mile S.S.E. from Great Hazeley.
Although very small, and now partly overgrown with brambles,
it appears to be the one seen by Dr. Fitton, by the officers of
the Geological Survey, and by Prof; Blake. It shows about
3 feet of very rubbly limestone full of Trigonia<j^%\,%.

A N.W. — S.E. line, parallel to the one already mentioned,
and about 4 miles distant from it, forms the limit of the
Portland beds in this district A third parallel line, at least

THE GEOLOGY OF THE THAME VALLEY. 31

3| mfles farther to the N.E., must be crossed before we see
lithological Portland beds again, but then they have an uninter-
rupted outcrop for over jo miles.

Main Outcrop, Thame to Bierton. — The first sign of the
reappearance of Portland beds, so far as I have seen, is in a field
on the north side of the railway and west side of Rycote Lane
(which here crosses the railway at right angles), close to the
hamlet of North Weston, a mile and a half west of Thame. The
brook which crosses the field runs apparently on clay, but, as the
ground rises, sand is seen thrown up in the molehills. This is a
pale, fine sand, with a little glauconite, totally different from the
" Lower Greensand " material that may be seen in the molehills
farther west beyond Rycote Pond. I know of no evidence but the
molehills in this neighbourhood. The field in question is shown
as either Lower Greensand or Gault (the former being stated to
he much obscured by drift) on the one-inch geological map, but on
the new Index Map a considerable stretch of Portland is shown
near here.

The first exposure of importance is at Priestend, the western
suburb of Thame, where a pit close to the new Grammar School
shows 15 feet of Portland Sand, compacted into sandstone in
places, covered by 5 feet of drift, containing flints, flint-pebbles,
quartzite-pebbles, and lydite-pebbles. The Portland Sand is dug
here for mixing with the Gault Clay at the new brickfields, a
third of a mile farther along the Shillingford Road.

The thickness of drift shown in this sand-pit illustrates
one of the difficulties of geological mapping in this neighbour-
hood; it was specially referred to in the memoir accompanying
Sheet 13, and is doubtless the explanation of the remarkable
diflerence in the lines drawn on the new Index Map. The drift,
however, varies rapidly in thickness, and in many places round
Thame there is no difficulty in determining the " solid " rock,
which here is most frequently Portland Sand.

As Fitton has remarked, the Portland Sand attains its widest
extension around Thame. The cart-road that runs direct from
Moreton to Thame is in parts so sandy that one might imagine
oneself close to the sea-shore. In the lane leading from near
Grove Cottage to the windmill, a deep ditch at the side shows
typical Portland Sands, slightly glauconitic. Small exposures may
also be seen at Moreton, at the side of the pond near the Bell
Inn, and in the roadside towards the eastern end of the village.
In Thame itself I saw an exposure in Pound Street, and the rising
ground north of the Kingsey Road (which is probably the Barley
Hill of Fitton) shows sandy soil.

Throughout the area between Moreton and Thame bounded
by the main roads running southwards from the latter, I have seen
no evidence of any limestone in the Portland beds, though Fitton
mentions its occurrence at Barley Hill. Whether this is to be

32 A. M. DAVIES ON

explained by Cretaceous overstep or lithological change is difficult
to decide, as the relation of the upper part of the Portland beds
to the overlying Shotover beds (if such they be) and Gault is
obscured by drift.

The Cuttle Brook, which flows past Moreton and Priestend
(not the similarly named brook near Kingsey) has cut down
through the sands to the underlying clay, a fact not recognised in
the one-inch map, but shown on the new Index Map. Near
Moreton itself the clay is largely covered by a peaty deposit, but
lower down the brook it is visible, and at Priestend two springs,
one on each side of the brook, probably mark the base of the
sands.

Fitton speaks of Portland Stone as quarried at Cotmore Walls
(Colmorewells Farm of the six-inch map), which is nearly half-
way between Thame and Towersey. It is probable that a
number of stone-pits have been closed in the neighbourhood of
Towersey and Kingsey, as I have failed to find any trace of
some mentioned in the Survey memoir to Sheet 13. The site of
the pits mentioned by Fitton as " near the windmill at Towersey "
can, however, easily be identified, although the windmill itself
has disappeared. They are about 200 yards south of the Kingsey
Road, to the east of the road that joins it from Towersey.
Nothing can now be made of them, but in the next field to the
south, a small opening has lately been made which shows Port-
land Limestone with Purbeck beds above. As very little of the
former is shown, the section will be described under the Pur-
beck beds (p. 39).

Portland Limestone is rather feebly exposed at the bridge
over the Cuttle Brook on the Kingsey Road, and at another point,
a quarter 6f a mile higher up the brook, as well as at the bridge
over the Ford Brook on the road from Kingsey to Haddenham.
Around Haddenham itself, there are practically no exposures,
though the presence of limestone can be easily recognised in
many of the ploughed fields.

The lower sandy beds, though, doubtless, forming most of
the lower grounds between Thame and Haddenham, are nowhere
well exposed to my knowledge, except in the lane leading down
from Scotsgrove to Scotsgrove Mill. Here 12 feet of typical
Portland sands are well shown, and near the top there is the
lydite-bed, surmounted at once by limestone with ^^ Ammonites
giganteus^^ above which there is again sand.

Along the left side of the Thame, between Scotsgrove and
Cuddington, the base of the lithological Portland is marked by
springs, of which one, the Yolsum Spring, has a distinctly ferru-
ginous taste.

We have now reached the neighbourhood of the Dadbrook
Hill section. The interesting field-pit near King's Cross will be
more particularly described under the Purbeck beds ; here we arc

THE GEOLOGY OF THE THAME VALLEY. 33

only concerned with the Portland limestone at the base of the
section. About 3 or 4 feet of chalky limestone is exposed, and is
highly fossiliferoas — Cardium dissimiie^ Pecten iameiiosus^ Trigofiia
inmoniana^ a large Ostreay and ^^ Ammonites giganteus^* being
abundant.

In addition to the trench-exposures down Dadbrook Hill,
both sand and stone are less distinctly exposed in the roadway on
the north side of the valley, rubbly limestone is seen in the lane
on the north side of Dadbrook House grounds, and chalky lime-
stone in the roadway at the top of the hill in Cuddington village.

Continuing eastwards, we soon come to the neighbourhood of
Dinton, where Fitton has described the section in a pit which had
yielded stone for over 200 years. Now the pit has long been
closed and converted into an orchard, but the name of " Stone-
pits " is still applied to the farm. The old stone-pit can be seen
from the footpath which runs from Westlington across the main
road and over the hill to the Cuddington road. '

Limestone is exposed in the fields south of Westlington
House, in the roadway by Dinton Church, in the farmyard at
Upton, and in a field north of the main road near the parish-
boundary between Dinton and Stone. At the County Asylum, just
beyond that boundary, a boring was made through 20 feet of
Portland beds and 500 feet of clays below, but the details known
are very meagre.

Just beyond the south end of the Asylum grounds, and a little
below the 300 contour, there is a spring which marks the base of
the lithological Portland. Beyond this, sloping down to the
Ford Brook, there is a stretch of low ground, which is an
inlier of Hartwell Clay. The boundary of this inlier can be
traced from near Ford north-westwards to Westlington and
Dinton, and round by Upton and Stone to Chilborough Hill
Farm. It follows the foot of a well-marked surface-feature, and
the difference in the soil when one passes from the clay to the
sands is readily noticed. It is possible also roughly to draw from
surface-indications a boundary-line between ** Portland Sand" and
"Portland Stone," which may here be a line of more value
than elsewhere. From near Wallace Farm (between Dinton and
Upton) a long tongue of higher ground runs out south-eastwards.
I have not been over this, but have no doubt that it consists
of Portland Sand, as mapped by the Survey.

The southern boundary of the inlier is much less definite.
From Ford to Chilborough Hill Farm I failed to find any trace of
lithological Portland, although an outcrop of it is marked on the
new Index Map (though not on the one-inch map), and Fitton
especially mentions "about midway between Ford and Moreton's
Farm " as one of the points where Portland limestone was to be
seen. The area through which the boundary must run is flat
grass-land ; clay only is exposed in the bed of the two branches of
February, 1899. J 3

34 A. M. DAVIES ON

the Ford Brook, and clayey material in the molehills. The only
point where anything appeared to intervene between the Gault and
Kimeridge Clays is near Bridgefoot Farm, where I saw pebbly
ferruginous sands, probably belonging to the Bishopstone beds.

Returning to the main Portland outcrop, we find the base of
the sands marked by the "Egyptian Springs," near Hartwell.
The sands are nowhere exposed in anything better than a molehill
anywhere between here and Aylesbury, but the limestone has been
abundantly quarried, and though many of the pits described by
Fitton and Morris are now filled up and grassed over, a good
many smaU exposures may still be seen. Such are the old pit 15b
yards south of Stone Church, where very chalky limestone with
abundant fossils of the usual species is seen, and a small pit at
Upper Hartwell, now made into a garden.

The famous Bugle Pit is the onl^ large exposure near here,
and has been so often described m the Proceedings and
elsewhere that I need not refer again to it. The extent to
which the Portland beds have been worked hereabouts is indicated
by the abundance of gigantic Ammonites used for wall decoration

Small exposures of limestone occur near Sedrup (Southwarpe
of the old maps), whence Fitton obtained several fossils ; but the
numerous pits that have been described at Bishopstone seem now
to be entirely closed and overgrown. The famous Locke's Pit,
where the Hartwell Clay is dug and the pebble-bed rather poorly
exposed, is about a mile and a half due north of Bishopstone.
The pebble-beds can be traced in the fields to the south of this
pit. Along the footpath from Bishopstone to Walton, limestone
is exposed in a small pit, about half a mile north-west of Stoke
Farm, which will be described under the Purbeck. Farther
along, limestone with Trigonia-ozsis is exposed in the side of the
brook which is crossed just before the path joins the Stoke
Mandeville Road. The rubbly limestone with the sands above
and below it is well exposed in the cuttings of the Metropolitan
Railway between Walton and the Aylesbury Joint Station.

Aylesbury itself is built on an outlier of Portland, detached
from the main outcrop by stream-erosion. The beds have
frequently been exposed in drainage operations and the like, but
I know of no good permanent exposure.

Leaving Aylesbury by the Leighton Road, one soon crosses
the narrow separation between the two outliers, the presence of
the Hartwell Clay being marked by a brickfield, from which the
characteristic fossils can be obtained in abundance. Above
10 feet of the clay the lydite-bed is well shown.

Less than half-amile farther on, on Bierton Hill, opposite the
Manor House, drainage works were in operation last September,
and a depth of perhaps 15 feet of Portland Sand was exposed,
with water at the bottom (indicating, in that very dry season, a
very near approach to the clay). As I only saw these exposures

THE GEOLOGY OF THE THAME VALLEY. 35

for a few minutes at dusk, I cannot say more, but the great
thickness of sand was striking. There are several old
stone-pits near Dunsham Farm, but only one now in work;
this shows a succession very like that of Hartwell, and the beds
dip 10^ to the east — a dip which must be cut off by the fault
shown on the published map.

At the brickfield in Bierton village Hartwell Clay, with
Astarte mysisj Mytilus auHssiodorensis^ Cardium striatulum^ and
Exogyra nana^ is seen to a depth of 15 feet or more, and, over-
lying it, the lydite-bed of the Upper Portlandian, here an impure,
brown, sandy, and pebbly limestone, with casts of large Trigonia,

This is the most easterly exposure that I have visited in the
district, but exposures have been recorded at Warren Farm, south
of Stewkley and near Cublington, in the drift-covered district
towards the north-eastern watershed.

Outliers : Long Crendon to Coney Hill. — This row of
outliers has been separated from the main outcrop by the cutting
of the Thame valley. Such a row of outliers is an unusual
feature in areas of gently-dipping beds with a well-adjusted
drainage system. Outliers beyond the main escarpment are
usually separated from it by the cutting back of head-waters, and
mark subsidiary transverse water-partings, or " sub-divides." An
explanation of the peculiar features of the Thame valley will be
suggested later on (Part VI).

The best sections on this line of outliers are at the extreme
ends. Those at Long Crendon I have already described. At
Coney Hill, or, more correctly, Waddesdon Hill, the following
section is now to be seen, at the " Limekiln " marked on the
six-inch map, a quarter-mile west of Coneyhill Farm, and near the
lodge at the northern entrance to Eythrope Park :

Section at Limekiln, ^-mile West of Conevhill Farm.

ft. in.

II. Soil, with small limestone fragments and lydite pebbles ... i o

10. Drift, with abundant limestone fragments I o

9. Calcareous sand, finely laminated i 3

8. Sandy marl O 8

7. Friable laminated limestone I 2

6. Massive limestone I o

5. Friable laminated limestone i o

4. Thin-bedded limestone about i o

passing into
3. Massive creamy and chalky limestone {Trigonia^ Cardium^

OstreOy Natica^ etc.) 2 o

2. Thin-bedded limestone and marl i 6

I. .Massive creamy limestone 2 10

The uppermost beds here are Purbeck, and the line between
Purbeck and Portland should probably be drawn at the base of
Bed 5, which yielded marine Ostracoda, found elsewhere in

36 A. M. DAVIES ON

the Purbeck beds of the district If this is the section seen by
Prof. Blake nearly twenty years ago, it must have been worked to
a much deeper level then, since it is from Coney Hill that he
obtained many of the '* rubbly limestone " fossils.

The lower rubbly limestone and the pale sands below it are
exposed in the roadside close by the quarry, and the base of the
sands can be seen at the pond below Coneyhill Farm.

In the intervening area between Long Crendon and Coney
Hill I have not seen any sections of importance.

Two further outliers — those of Ashendon and Lodge Hill
(capped by Waddesdon Manor) — ^run parallel to the line just
referred to, being separated from it in more normal fashion by a
secondary longitudinal stream. I have not visited either of these,
but their appearance from a distance clearly indicates their
nature. The south-westerly continuation of this line of outliers
is represented by the north-westerly extension of that of Long
Crendon to Chilton.

Outliers : Brill and Muswell Hills. — My only visit to
Brill and Muswell Hill was a brief one, and I have nothing to add
to the accounts that have previously appeared. I may point out,
however, that in the presence of only 3 feet of mealy sand
between the lydite-bed and the fossiliferous Hartwell Clay, this
district shows characters intermediate between Long Crendon and
Dadbrook Hill.

It seems possible that these outliers owe their preservation to
being on a gentle synclinal axis at right angles to the general
strike — an axis which may find its continuation in the break of the
line of Cornbrash inliers between Merton and Blackthorn Hill.
The other breaks in that anticlinal line also seem to be continued
as synclinals into our district. But where the dip averages less
than half a degree, and horizons are not certainly marked by
lithological lines, the recognition of such gentle folds is difficult.*

Outliers: Quainton Hill and Oving. — The base of the
lithological Portland rises through 200 feet in the six miles
between Aylesbury and Quainton Hill. This indicates a dip
which, though double that estimated at Dadbrook Hilt, is con-
siderably less than half a degree. There are several pits and
small exposures on Quainton Hill, but not enough to enable a
complete section to be compiled. As elsewhere, however, the
lower part of the Portland beds is mainly sand, the upper
calcareous.

On the eastern side of the northward spur, called " Conduit
Hill," about 30 feet above a spring, which marks the base of the
sands, a small opening showed a little rubbly, fossiliferous lime-
stone with Cytherea rugosa and FUuromya telitna, overlying 3 feet

^ • Some general suggestions as to post-Juras&ic folds, based on a comparison of this dis-
trict with the distribution of Jurassic rocks under the London area, were made in the paper
as originally read. They are withdrawn with a view to fuller treatment later.

THE GEOLOGY OF THE THAME VALLEY. 37

of calcaureous sand with large concretions, like those of Littleworth,
near Wlieatley.

A furlong south-west from the summit of Quainton Hill a
larger opening showed the following section :

Section a Fcrlong South-East of the Top of Quainton Hill.

ft. in.
Shoto\'ER I 6. Ferruginous sands with ironstone ; clay at base

Bids (?) \ in olaces ^ 8 o

fS. Brasny limestone ( TV^tfjtw) 2 6

I 4. Creamy limestone (^/rigonia casts, Cardium

Portland ' dissimile, Ostrea etc) 6 o

Beds ^ ^' ^^°* ^"^ sands, slightly glauconltic, not

calcareous 6 o

I 2. Sandy and shelly limestone 20

'v^i. Calcareous sands.

This seems to show what Fitton calls a " gull," />., a pipe in
the Portland beds, into which the overlying clay and ferruginous
sands have been let down gently. Fitton, it is true, asserts that
the gull must have been excavated before the deposition of the
matter that now fills it ; but in the case he mentions (at Great
Hazeley), as well as in the present one, there are among the beds
filling the gull clay-beds of uniform thickness. It would be
impossible for such a bed to be laid down on a slope of from
45^ to nearly 90® without being much thicker at the
bottom, therefore we can only suppose it to have been level
originally, and let down long afterwards.

Several smaller sections near the top of the hill show Port-
kind limestone, but with overlying Purbeck beds; they will
therefore be considered later.

Eastwards it is easy to see that the Portland beds extend some
way beyond the limits laid down on the published map. The
proper shape of the outlier is roughly indicated on the key map.
Fig. I. It includes Woad Hill and Den ham Hill. On the
latter, a little way above Denham Hill Farm, I found a very
obscure section, seemingly with a fault running through it, the
beds differing totally on the two sides, and being greatly obscured
by talus-slope. There are marly and clayey beds suggestive of
Purbeck, and more massive limestone, but nothing very satis-
factory : in the former I found a single marine ostracod
{Bythocypris winwoodiana, see Mr. Chapman's notes, p. 58).

Close by, in the next field, to the west, an indentation of the
500 contour line marks an old quarry where limestone may be
seen. Lower down the hillside a couple of springs mark the
base of the lithological Portland. In the case of the more
westerly one there is a fair exposure of calcareous sands (in which
I noticed a TngomaoLSt) over the clay, and from here to the
lowest point where limestone can be seen is quite 30 feet vertically,
all between seeming to be sand. This agrees with observations

38 A. M. DAVIES ON

at the north end of the hill, and I think we may safely r^ard the
lowest 30 feet of the lithological Portland as entirely sand, while
the remainder is mainly, but not entirely, limestone. The thick-
ness of the latter I can only estimate by considerations of level,
and those give it about 45 feet, making 75 feet in all. I have not
seen any sign of the lydite bed on Quainton Hill, but that
may be because at the time I visited it I was not impressed
by the importance of the lydite bed, and did not look for it

The outlier around Oving was visited by the Association in
1897, and the exposures there are chiefly interesting for the
Purbeck beds. At two points there are sections showing
fossiliferous Portland limestone overlymg sand — one (visited by
the Association in 1897) is on the road to North Marston,
100 yards before it crosses the 500 contour. The other is by
Creslow Church. Here 5 feet of limestone are seen, with a
marly band in the middle, and over 3 feet of the usual pale sand
beneath. The limestone here is very fossiliferous — " Amm.
giganteus,** Trigonia^ Cardium dissimile, Ostrea expansa^ Natica^
etc., being present, and a small Ostrea occurs in the sand.

Limestone with sand underneath is seen in Weir Lane, north
of Bolbec Castle, Whitchurch, though the Portland sand was not
mapped at this point by the Survey. Limestone also forms the
actual roadway in part of Whitchurch village, as Prof. Blake has
noted.

IIL— PURBECK BEDS.

The marine Portland beds are followed conformably by a
series of marls, clays, and thin-bedded limestones containing
estuarine and fresh-water fossils — the Purbeck beds of the dis-
trict. In adopting this name for them, I express no opinion as
to their equivalence with the typical Purbeck beds of the south
coast. I use the name as a facies-name, not a time-name.
Owing to the pre-Cretaceous (or early Cretaceous) denudation of
the Jurassic rocks, these uppermost strata do not possess a
continuous outcrop but occur in scattered patches, irregularly
overstepped by the Cretaceous beds above. Being nowhere of
great thickness, and having no lithological unity, the recognition
of their presence from surface-characters is extremely difficult ;
though in a section they are readily distinguished from the more
massive limestones beneath. It is not surprising, therefore,
that no attempt was made to map them on Sheet 13 of the
one-inch map, although their presence was recognised, and
that on Sheets 45 and 46 only seven patches of Purbeck are
mapped, although at least a dozen seem to have been known to
Fitton. Altogether I find previous evidence of sixteen, and to
these I can myself add two, making a total of eighteen, of which
some may be only parts of a single patch. Of these patches

THE GEOLOGY OF THE THAME VALLEY.

some are outliers, one is mapped as an inlier, while others, being
of the nature of discontinuous outcrops, might be spoken of as
"in-and-out-liers," or " tween-liers."

I. and 2. Combe Wood and Garsington. — Purbeck beds
are recorded from these two places by Fitton. I could find no
exposures

3. Long Crendon. — Here also they were noted by Fitton.
I have given the section now exposed at page 22. For fossils
see table on page 43.

4. Bkilu— Purbeck beds have been noted here by Brodie
and Phillips.

5. Towersey.— Purbeck beds have not yet been recorded
from here. In a pit close to the site of the windmill (now de-
stroyed), half a mile north of the village, the following section
may be seen :

Field-pit on E. Side of Road from Towersey to Kingsey, nearly
OPPOSITE Site of Windmill.*

PlRBECK. i

Soil

Portland.

Band of nodular calcareous chert

Thin-bedded limestone

Marl, with nodules at base

Thin-bedded limestone

Marl with Paittdina

6. Thin-bedded limestone

5. Ferruginous sand, slightly clayey

4. Marl

3. More massive limestone

2. Thin-bedded limestone

I. More massive limestone (^Cardium dissimili)

in.
o

4
8
6
9
3
3
8
o
II
o

Bed 5 is conspicuous on the face, because of the moss that
grows along it. Bed 7 is full of young PaiudincB of indeterminable
species, but two of the larger ones appeared to be P. elongata
and P. sussexiensis, I also found a single tooth of a pycnodont
fish (Casiodus ?) and some freshwater Ostracods (see p. 43).

The Purbeck beds cannot extend far around these pits, as
Fitton does not mention their occurrence in the old pits a furlong
to the north, and I could not find any clear evidence of them
between the Portland and Gault along the Cuttle Brook, a
quarter-mile to the west.

6. Haddenham. — A small outlier, partly overstepped by
** Lower Greensand," has been mapped a little west of the village.
Ttiere was probably a pit here at one time, for Fitton specially
mentions this as a locality where Portland beds may be seen
rising from beneath the higher strata. Now, however, I have
foiled to find any evidence of the presence of Purbeck here.

Photographs of this section and the next one (Kinx's Cross) have been given by Mr. J.
H. Pledge to the British Association collection.

40 A. M. DAVIES ON

7. King's Cross, north of Haddenham. — At the point where
this stone-pit (already referred to in the Dadbrook Hill section,
PP' 22, 33) is opened, the Geological Survey has mapped Gault
resting directly on Portland Stone. It is probable that the black
clay and marl of the Purbeck (Beds 6 to 9 of the section below)
were mistaken for Gault — not a surprising mistake in the absence
of any clear section. The fossils given below are amply sufficient
to prove the Purbeck age of the beds.

Field-Pit, N. Side of Main Road, 120 Yards West of King's Cross,
Haddenham C1898).

ft. in.

10. Soil (and Drift ?) o 6

9. Yellowish-white marl i o

8. Brownish clay, slightly calcareous 2 o

7. Tough black clay, scarcely calcareous at all 2 o

6. Brownish, more laminated clay, sandy and not calcareous.

the lowest portion weathering with a white eflflorescence i o
5 Reddish sand with some lydite- pebbles, and thin iridescent

shell fragments; ironstone at base in places ... about o 7

4. Dark marl with pebbles 7 in. to i 2

3. Lighter marl, the lower part giving an odour of

petroleum when hammered ... about i 6

2. Marly limestone o ^h

I. Massive chalky limestone, with Cardium dissimiie,

Trigonia damoniana^ ^^ Amm. giganteus'^ Pec ten ^

Ostrea^ etc. 3 6

There are slight traces of contemporaneous erosion between
4 and 5. It is even possible that this may indicate a break of
some importance, for the ostracods found in Bed 7 indicate a much
higher horizon than those in Beds 3 and 4. From Bed 7 I
obtained fine specimens of Cypridea punctata (Forbes),
undeterminable fragments of Gasteropods and Lamellibranchs,
and carpogonia of Chara. Of the Cypridea punctata,
Mr. Chapman writes to me that it is characteristic of the
Upper and Middle Purbeck, but very rare in the Lower.
"The fine and numerous specimens are, I should say, rather
indicative of the Upper series, but that can only be said
with some reserve." In Bed 3 there is a curious mixture of fresh-
water and marine ostracods and foraminifera. The former are
given in the table on p. 43, and are Lower Purbeck forms.
Among the latter Mr. Chapman identifies Cristellaria cultrata
(Montfort), from the middle part of the bed, and C varians,
Bornemann, from the top, and states that " in addition to these
there are several interesting foraminifera from the same bed
which will require further study." The only other identifiable
fossil was a Serpuia, but fragments of oysters occur at the base.

Since this paper was read I have been in correspondence
with Mr. Jukes-Browne, of the Geological Survey, who re-
examined this district officially in 1887, and saw the section at

ft.

to 2

to li

THE GEOLOGY OF THE THAME VALLEY. 4 1

this pit. As the section then exposed differs to some extent from
the present one, I am glad to be able to give Mr. Jukes-Browne's
account of it, which he has kindly allowed me to do, with the
permission of the Director-General of the Geological Survey.

Stone-pit f mile S. of Cuddington.

Soil (heavy)

6. Marly rubble with bits of stone passing down into

marly clay

5 Light-grey calcareous clay with a lenticular bed of
limestone near entrance to pit, above which is a

continuous band of dark grey clay

4. Grey soapy clay, passing into bbck clay

3. Dark brownish shaly clay, with brown (ferruginous) and

yellow (sulphur) stains

2. Brown sand full of comminuted shells in the upper part,
with some pebbles of limestone
^ I. Hard calcareous laminated sandy loam with derived

shells at base

Hard white Portland rock

Total about 16

[No. 2 thickens at the expense of No. I.J

A comparison of the two sections shows several interesting
Joints. It is safe to assume that the present face is farther east
^iian the 1887 one. Beds 3 to 5 of the latter correspond exactly
^o Beds 6 to 9 of the former, the differences being much slighter
^iian the verbal differences in the description might suggest ; the
lenticular bed of limestone, however, has now thinned out
"Altogether. Bed 2 of Mr. Jukes-Browne is my Bed 5, and its rapid
'^estwardly increase in thickness is in full accord with the
Evidences of contemporaneous erosion at its base : evidently we
l^ave here a stream-channel cut down in the estuarine or lagoon-
deposits below, in which latter, throughout the district, sandy
l^eds are very rare. Bed i of Mr. Jukes-Browne is probably the
lower part of my 3 and 2, having changed in lithological
.^^haracter.

It is very difficult to say how far these Purbeck beds extend

Ground this pit, as surface-indications are not at all trustworthy in

<iistinguishing Purbeck from Pordand, unless the former are very

c^layey. The only other point where I have actually found Purbeck

Ttiarl in place is in the roadside ditch by Budnall Farm ; but the

clayey soil of the fields on the opposite side of the road indicates

Its presence there. The boundaries drawn on the map (p. 54)

must, therefore, be taken as approximate only ; they are based

\argely on considerations of slope and dip, and only to a small

extent on actual tracing over the ground.

8 AND 9. From Ctiddington to beyond Dinton two
parallel strips of Purbeck, separated only by the overstepping
Cretaceous beds, have been mapped by the Survey. These are

A. M. DAVIES ON

doubtless continuous with one another, and with the previous
patch, underneath the Cretaceous. I know of no good exposures
along this line, but it includes the Dinton stone-pits described by
Fitton (see ante^ p. 33).

10. Stone. — This large outlier has the Bugle pit as its only
satisfactory exposure. The most notable feature here is the fine-
grained and well-jointed bed of "Pendle" at the base. The
working-back of the quarry-face has revealed the rapid lateral changes
which the Purbecks undergo. Thus the face worked at the
present time (November, 1898) shows six feet of unbroken marl,
separated from the pendle by seven inches of crumbly limestone,
and five inches of slaty-blue clay. Tracing the beds some yards
to the south, in an old face we find the marl broken up by three
bands of rubbly limestone.

II AND 12. BiSHOPSTONE Area. — A large area is mapped by
the Survey as Purbeck between Stone and Bishopstone, with a very
small inlier in Bishopstone village itself. A number of pits are
referred to by Fitton, Morris, and Rupert Jones as within this area,
but, though I have seen several overgrown and partially-levelled
pits, I have not found one still in use, or even recently abandoned,
and very few are marked on the six-inch map now nearly twenty
years old. Purbeck Marl may be seen occasionally in ditches.

13. Aylesbury. — A small patch of Purbeck that can hardly
cover ten acres is shown on the Survey map about half-way between
Stoke Farm and Locke's brickfield. A small pit is open in this
patch beside the Walton-Bishopstone footpath, and within the
parish of Aylesbury, and though not now in use shows the
following section very clearly :

Section in Field, I-mile frcm Walton Along Bishopstone
Footpath.

Purbeck.

Portland.

/8. Soil (and drift ?) ...about

7. Thin-bedded limestone ... ... ... i

6. Light-coloured marly limestone o

5. Dark marly limestone o

4. Crumbly, very thin-bedded limestone with

, ostracods o

i 3. Chalky limestone, rather thin-bedded ... 4

< 2. Marl, passing up into clay o

( I. Chalky hmestone 3

ft. in.

2 O
O
6
8

This section is chiefly of interest from the occurrence in bed
4 of the same mixture of freshwater and marine ostracods and
foraminifera as in Bed 3 of the King's Cross section. Of the
latter Mr. Chapman identifies Cristellaria sp. and Fatellina sp.
The former are given in the table opposite.

14. Coney Hill. — The section has been given on page 35.
For a list of ostracods from bed 5 see opposite.

THE GEOLOGY OF THE THAME VALLEY.

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A. M. DAVIES ON

15. QuAiNTON Hill — The existence of Purbeck beds under
the "Lower Greensand" was noted by Fitton, but they were
evidently too uncertain to be mapped. The section previously
given (p. 37) shows that they are locally wanting. The best
exposure I have seen of them was in a small pit by the eastern
boundary of the field which includes the summit of the hill. An
opening is indicated here on the six-inch map, but this has been
levelled over, and the new one is a few yards farther south. It
was evidently worked for the Portland limestone, of which many
blocks were stacked up close by, but, as is usual with small
pits, the bottom part had been filled in.

Section 160 Yards East of the Summht of Quainton Hill.

ft. in.
5. Soil, full of " Lower Greensand " material,
the lower 8 inches, perhaps, being *' Lower
Greensand " in situ i 6

Purbeck.

Portland.

i' 4. White marl, passing down into (3)

J 3. Finely laminated limestone

J 2. Hard limestone with shells andostracods, the
( latter specially abundant towards the top
i I. Soft marly limestone with 7V/^j»ia-casts,
I PecteHy etc. ... •••

o 4

Bed 4 varies much in thickness, so that if " Lower Green-
sand " is really in situ above it, the unconformity between them
is strongly marked.

16. OviNG. — A large outlier of Purbeck is mapped here, and
is well exposed in a large number of small pits that have been
worked for Portland Stone on the flat top of the hill. They show
considerable variation in the lithological character of the beds,
but it does not seem necessary to give the details of them in full.
This outlier was visited by the Association in September, 1897,
and some account of what was then seen appeared in the
report of that excursion {Proc. Gtol, Assoc., vol. xv., p. 207).
In the section given on p. 207, I should now have no hesita-
tion in carrying the Purbeck down to Bed 2, inclusive ; while I
am very doubtful if the " Lower Greensand " marked there is
really in situ : more probably it is only sandy soil.

17 and 18. — Weedon; and Warren Farm, near Stewklev.
— I have not visited these two outliers, whence Purbeck fossils
were recorded by Fitton, but where the outcrops were evidently
too narrow to be mapped by the Survey.

IV.— THE " LOWER GREENSAND."

Under this name the Geological Survey has mapped within
the district a discontinuous series of patches consisting mainly of
ferruginous sands, with frequent beds of ironstone, pebbles, and
clay resting on the Purbeck or the Portland beds, usually with

TH£ GEOLOGY OF THE XUAME VALLEY. 45

marked imconformitj, and in places covered by Gault. Though
mosdj onfossilxleroQS^ dier have yielded fossils in at least five
pbces in our district — marine at two, freshwater at three. Since
k is by no means certain that these numerous disconnected
patches, aboat thirty in number, are all of the same age, it seems
very desirabte to imroduce local names for the description of the
fbssilileroas beds and those stratigraphically connected with them,
and to leave the vague term '' Lower Greensand " for those cases
which cannot with certainty be otherwise defined. I shall, there-
fore, in this paper speak of them under the following names :

(i> Toot Baldon Beds. — These are the beds extending from
near Chislehampton to the Thames at Clifton Hampden and
Calham. In them marine fossils of Aptian age have been
found.

(2) Shotover Beds OR Shotover Ironsands. — This name
has been very generally used as a descriptive term. Prof. Blake
JD 1893 proposed that the term " Shotover Sands " should be used
for (apparently) all the " Lower Greensand " of this district. As
Prof. Blake had himself used the same term in 1880 for the
Portiandian sands of Shotover Hill, I think a revival of the old
term of " Ironsands " used by Fitton is more satisfactory. I pro-
pose that the term be restricted to the beds containing freshwater
fossils, or stratigraphically linked with those that contain them.

An important stratigraphical distinction of these beds from
the next hes in the two facts that the Shotover beds rarely or
never rest direcdy on Kimeridge Clay (the supposed case
at HTieatley being due to slipping) and that they rarely approach
near the Gault.

(3) Bishopstone Beds. — I propose this name for the beds
developed around Bishopstone, Stone, and Haddenham Low
which have yielded marine fossils, though none that definitely fix
the age of the beds. The village of Stone has the first claim to
give its name to these beds ; but as " Stone " has a lithological as
well as a geographical meaning, its use might lead to misunder-
standing.

(4) WoBURN Sands. — I shall use this name in referring to the
continuous outcrop of sandy beds with Aptian fossils that starts
near Leighton Buzzard and continues north-eastwards towards
Sandy and Cambridge. These beds are entirely outside our
district, but it will be necessary to refer to them for comparison.

(i) Toot Baldon Beds.

These are, at Toot Baldon itself, fine clayey sands, probably
about 20 or 30 feet in thickness. Farther west, towards Nineveh
Farm, the clayey character seems to disappear. They are seen
again at the little cliff at Clifton Hampden, but here they are far

4b A. M, DAVIES ON

coarser, forming a gravel of small pebbles, rarely over i inch in
length. These pebbles are mainly quartz, but some are of iron-
stone, and others again are of light-coloured argillite, very perfectly
cleaved, so that they break between the fingers along planes
almost as perfect as those of a calcite-crystal. This material I
have seen nowhere else in the district, but I have found similar
()ebbles in the Faringdon sponge-gravels. Coarse gravels are
again seen just north of the brickyard at Culham, but in the brick-
yard itself only a few inches of pebbly, glauconitic stone intervene
between the Gault and the Kimeridge Clay.

At Toot Baldon itself, in such roadside exposures as could be
seen, I hunted for fossils unsuccessfully. There are two previous
records of fossils from here. Prof. Hull and Mr. Etheridge
found Ammonites {Hoplites) deshayesii and Ttrebratula stlla^ con-
vincing proofs of Aptian age. On the other hand. Prof. Phillips,
in i860, found, towards the base of the sands, Mya^ Pecten^
Cardium^ Trochus, and "an Ammonite of the group of A.
polyplocus^ A. triplicatus^ and A, giganieus^' i,e,, one of the
Planulati of Von Buch or the modern genus Perisphinctes.
This last fossil is much more suggestive of Upper Jurassic,
but as the genus does extend into the Lower Cretaceous,
it can hardly weigh against the evidence of the other two species.
Still we must not overlook the possibility that here, scarcely more
than a mile from Garsington, there may be a trace of the lower
sandy beds of the Portlandian beneath the Aptian sands.

(2) Shotover Ironsands.

These famous beds at Shotover itself have beexi a source of
constant discussion, and have been referred variously to the
Purbeck, Wealden, and Lower Greensand.

Under the heading, " Shotover Ironsands," I include not only
the beds on Shotover Hill, but also those extending from near
Wheatley to Garsington, and those at Brill — in all of which
freshwater fossils have been obtained. To these may probably
be added the beds on Quainton Hill, from which Fitton obtained
impressions of Cyclas and Paludina, If unfossiliferous beds may
be allowed a place, I would add those of Long Crendon and
Thame, as lithologically more like those of Brill and Shotover
than those of Stone, but I know the weakness of such evidence,
and only adopt it temporarily in the absence of better.

Shotover Hill Range. — Here the beds were estimated by
Phillips as 80 feet thick. They include sands (both white and
reddish), ironstone, and clay (white and red). At Shotover
iteelf they rest on sandy Portlandian beds without any intervening
limestone, so that their exact lower limit is not easy to fix.

Between Wheatley and Garsington I could find no satisfactory

THE GEOLOGY OF THE THAME VALLEW 47

exposures, except a small sand-pit just by the 400 feet contour, a
quarter-mile due south of Littleworth, where 5 feet or so of white
and grey sand, fiadse bedded and variously iron-stained is
surmounted by a few inches of white clay, and this again by 3
feet oi ironsand-slip. Many specimens have, in the past, been
obtained from Combe Wood, a mile south of WheaUey; but I
could find no quarry there. Judging from the soil of ploughed
fields, the beds are mainly coarse ferruginous sands, passing into
ironstone. North of Garsington, in the hollow lane leading down
to Kiln Farm^ these sands are seen to overlie a white clay, under
which are again ferruginous sandsof nogreat thickness (see Plate II).
It is probably this clay that throws out the springs all round the out-
lier, the sand above holding an abundance of water even in time
of drought, as I found with considerable pleasure during the
hottest and driest part of last summer, when these springs con-
tinued to flow plentifully though many of those at the base of the
Portland were dried up.

All over this outlier the base of the Shotover beds seems to
vary greatly and irregularly in level, whereas the Pottland beds
below appear to have a very regular and gentle dip towards the
south-west. Granting that coarse freshwater sands may well have
been laid down originally on an uneven surface, it is probable
that most of this irregularity is due to subterranean erosions of
the top beds of the Portland and Purbeck as shown by Fitton's
" gulls " at Great Hareley {an/f, p. 37). The exact boundarv-
line of the Shotover beds is also difficult to trace in many
places, by reason of the extensive slipping that has uken place down
the hill-sides. As I have previously shown (pp. 28, 29) this slipping
has been taken for overstep between Wlieatley and Littleworth.
It is well shown in the lane-section north of Garsington, and
I suspect its existence at other points. It is not unlitcely that the
subterranean erosion of the underlying beds, where it has given
the Shotover beds a dip towards the hill-side, has been the
ultimate cause of the slips. I need hardly point out that the
discrimination between slip, irregularity due to subterranean
erosion, and original overstep (which also exists almost certainly)
is a troublesome matter along a line where exposures are few, and
I have not attempted it in deuil.

MuswELL Hill, Brill, Long Crendon, and Thame. — At
Brill there are abundant exposures of the Shotover beds at the
top of the hill, but there seems to be much slipping, and in the
short visit I paid I did not determine any r^ular sequence, though
I estimated the beds at 50 feet in thickness. They are a very
variable set of sandy and clayey beds — the sands white, pale
violet, and reddish ; the clays blue, violet-black, and dark
brown.

On Muswell Hill the sands seem to be mainly ferruginous,
but I did not notice any good exposure.

48 A. M. DAVIES ON

At Long Crendon the beds are plainly seen lying between the
Gault and the Purbeck, and are only 4 feet thick. One section
has already been noted (p. 2 2 and Plate II). Another, 50 yards. or so
farther north, showed a rapidly varying set of sands and clays.

In the brickfield, a quarter of a mile south of Thame station,
there are several small openings, one showing fossiliferous Gault ;
another purplish-grey and yellow sands, with ironstone above' and
below ; and a third, soft white clay. This seems to be the
descending succession, but I could make out no actual junction.

The characteristic features of these beds from Brill to Thame
are the abundance of clay and fine clayey sands, and the rarity of
coarse sand and pebbles.

I have not been able to trace the beds east and west of
Thame owing to the abundance of drift, and the absence of any
limestone between them and the Portland sands. In the section
near Towersey (p. 39) nothing was seen above the Purbeck,
although according to the Survey map Lower Greensand, if not
Gault as well, should here be present.

QuAiNTON AND OviNG. — The cxposures I have seen on
Quainton Hill all show ferruginous sands with pebbles, and
might just as well be correlated, on lithological grounds, with the
Bishopstone beds as with the Shotover beds. But as Fitton
obtained casts of freshwater shells from them, I include them
here. They appear to rest on Purbeck or Portland beds with a
strong unconformity ; but in one pit at least (p. 37) this is due
to subterranean erosion of the underlying beds.

At Oving, the only section I know of was visited by the
Association in 1897, and is described in the report of that visit
in these Proceedings.

Bishopstone Beds.

Bishopstone to Haddenham.— These extend from just north
of Haddenham in a broken curve, along the. line of high ground
followed by the main road from Thame to Aylesbury, and down
to Bishopstone, where they appear to pass under the Gault. In
addition there are a number of small outliers mapped by the
Survey.

The general sequence of these beds is shown in Plate II (Stone
and Hartwell section). The best exposure is that at the Wind-
mill, Stone. During the last three or four years this has been
actively worked, and its appearance has varied to some extent. It
was at its best about the middle of May, 1898, when it showed a
very pretty fault on the two end faces, running parallel with the main
face, /.^., almost due east and west, with a downthrow of a couple
of feet or so to the north. In September my friend Mr. Pledge
took a photograph of the section, a copy of which is now in the
British Association collection. The details of this section have

THE GEOLOGY OF THE THAME VALLEY.

varied somewhat from time to time,
mcnts were taken in March, 1897 '

The following measure-

Windmill Sand-Pit, Stone.

6. Sandy clay

5. Sand and ironstone

.4. Sandy clay

3. Sand and ironstone

2. False-bedded white and grey sand with pebbles, from

5ft. 6 in. to
I. True-bedded firm grey sand ,

ft.
3
o
o

7
3

in.
4
9
3

9
6

This section shows evidence of the following series of events :
(i) Deposition of the lowest sand in relatively still water.

(2) Removal of part of it by currents and deposition of
pebbly sand at various angles.

(3) Truncation of the false-bedded sands by a horizontal
plane, and deposition of sandy clay, etc., in comparatively still
water.

A noteworthy feature of this pit is the absence of ferruginous
sands, which are seen in other pits close by. The three following
sections will illustrate the variations in the character of these beds.

Mr. Castle's Pit, i mile along Eythrope Road, Stone.

ft. in.
6. Sandy soil /

5. Bluish-white plastic clay )*

4. Bright orange sand

3. Whitish sand

2. Black loam

I. White sand, with a few seams of black loam ; few pebbles,

some false-bedding 120

S o

X o

o 6

2 o

Mr. Castle's Pit, south of Stone Villas, Stone.

6. Soil and drift 2 6

5. Clayey sand o 4

4. Clay o 9

3. False-bedded sand with pebbles and ironstone 6 3

2. Lenticular band of Fuller's earth up to 09

I. False-bedded sand, etc 10 o

Old Sand-pit, North side of main road, East of Stone Farm,

Stone.

ft.
5. Soil I

4. Clay

3. Clayey sand

2. Clay

I. Light-coloured sand

In.
6
6
8
o
o

In this last pit, the beds given are capped, a little farther
east, in an old, obscure face, by a band of hard ferruginous
conglomerate of small pebbles. This conglomerate does not
seem to extend far.

In none of these sections is the base of the sand exposed,
February, 1899.] 4

50 A. M. DAVIES ON

and in none could I find any trace of fossils. Morris recorded
Endogenites erosa from the base of the sands in Stone village,
but the only marine fossils which he obtained were from his
" Red Sand Pit," the site of which I have identified as in the
field which lies between Peveral Court grounds and Galley Farm.
This site is marked by a depression of the ground, evidently
artificial, and it agrees with the order in which Morris described
the pits. When I first visited this field, in March, 1897, it was
ploughed over, and the pebbly ferruginous sands were well seen ;
but on returning there, in 1898, in the hope of finding fossils, I
was disappointed to find the field in grass. This pit is not on
the same outlier as those above described, but on a smaller one,
south of the main road.

The fossils from this pit are preserved at University College,
and through the kindness of Prof. Bonney I have been able to
examine them, and they were exhibited at the meeting on
Decemoer 2nd, 1898, when this paper was read. They include
a very good piece of coniferous wood, and casts in coarse sand-
stone of a small coral, PecUn^ Spondylus^ and other marine shells,
including one identified as Exogyra sinuata. If this identification
is correct,* it fixes the age of these beds pretty closely, since
that species does not occur below the Atherfield clay and its
equivalents (Rhodanian or Urgonian), though it ranges to the top
of the Lower Greensand (base of Albian).

Besides these indigenous fossils, Morris describes the occur-
rence of derived blocks of compact brown sandstone, with casts of
Unto, Cyrena, Paludina, and traces of plants. Only one fragment
of such sandstone is preserved in the collection that I saw at
University College, and the casts in that do not seem enough to
establish the freshwater origin of the sandstone. I may mention
that I found one block of coarser sandstone full of casts of a
gasteropod {Paiudina ?) at Gastle^s pit, near Stone Villas, but
unfortunately it was in the soil, not in situ, and therefore proves
nothing.

In the "Explanation of Horizontal Section Sheet 140," casts
of marine fossils in " gritty and ferruginous beds between Hart-
well and Bishopstone " are recorded. These may be from Morris's
pit, or from some other one. I know of no pit open at present,
or even recently abandoned, between Hartwell and Bishopstone.

I may say here that I feel very doubtful as to the correctness
of the mapping of the little outlier in which this pit occurs. The
topography of the old one-inch map is quite clear and fairly correct
at this point, and the outlier is shown as about 370 yards broad,
extending south-westwards to within about 200 yards of the Stone-
Bishopstone road, and north-eastwards to within about 130 yards

* I am not sufficient of a paleontologist to venture to express an opinion on the
specific identity of a cast ; but at the meeting Prof. J. F. Blake expressed his opinion that
<)ne of the specimens was certainly Exogyra. sinuata.

THE GEOLOGY OF THE THAME VALLEY. 5 1

of the Galley Farm lane. Now over the greater part of this
breadth the ploughed soil shows nothing but limestone-fragments
and some flints. The only field in which the ferruginous sands
occur is the squarish one previously described, and that lies on
and beyond the north-eastern limit of the outlier as mapped.
Moreover, if only six feet of sands were present at Morris's pit, as
he states, the foil of the ground thence to the next field to
the south-west would take us at once on to the Portland
beds. Of the north-west and south-east extension of the
outlier I cannot speak, nor of the further patch passing under the
Gault at Bishopstone. This last is the only point where the
Bishopstone beds are shown on the Survey map as underlying the
Gault at its outcrop, but, as already mentioned (p. 34), I have
seen an exposure of them, close to the Gault, at Bridgefoot Farm,
near Ford.

Westwards from Stone comes another long outlier, capping the
high ground along which runs the road from Aylesbury to Thame.
The ferruginous and pebbly sands are everywhere to he seen in
the fields, but about the highest part of the ridge they are capped
by sandy clays, mapped as Gault on the one-inch maps, but pro-
l^bly answering to the top beds in the Windmill section, Stone
(see p. 55, later). These beds are worked at Haddenham Low
brickfield.

At Haddenham several outliers are mapped, and the
soil by the eastern windmill seems to indicate the existence of
an extra one there.

Hazeley to Rycote. — I include the sands which crop out
beneath the Gault along this line in the Bishopstone Beds on
general stratigraphical grounds, but without any palaeontological
evidence that they are marine. In the fact that they follow
the Gault outcrop we have a suggestion of conformity to that
formation, and the great lithological difference between these beds
up to their easternmost appearance at Rycote and the beds at
Thame, which I class as freshwater, lead me to regard these as
a different series.

According to the Survey map they begin about a mile south
of Great Hazeley with a duplicated outcrop due to a strike-fault,
and they cover a considerable area around Great Hazeley itself,
thence running with a sinuous outcrop by Great Milton to the
south side of the valley of the Chil worth Farm Brook, where they
are overlapped by the Gault ; two windmill-marked outliers on
the )eft bank of the Thame forming a link towards the Combe
Wood outlier.

I cannot myself speak for any point south of Great Hazeley : on
the north side of that village the old stone-pits described by Fitton
are certainly capped by ferruginous sands, but I could see no
evidence of their presence in the village itself ; on the contrary,
there is what seemed to me to be an outcrop of limestone in the

52 A. M. DAVIES ON

roadway, and in the little quarry described on p. 30 the limestone
came immediately under the soil. Some alteration in the mapping,
therefore, seems necessary here. I have also been over the
ground occupied by the southern of the two ** windmill " out-
liers, and to judge from the soil of the fields it is much smaller
than is shown on the map.

To return to the main outcrop, we find the beds well exposed
at the stone pit. Great Milton (p. 29, ante). The main face now
being worked faces due west, and shows the section given by Mr.
H. B. Woodward in his Jurassic Memoir, viz. :

ft in.

Brown loamy soil.

Sand with bands of white and ochreous clay, with
lignite 3 ft. to 6 o

Buff and white false-bedded sand with ferruginous layers
and concretions ; with at base lydite pebbles and iron-
stone 3 ft- to 6 o

In an old face to the north-west the sandy beds are very thin,
only about 4 inches occurring between the upper sands and clays
and the ironstone with pebbles (7 inches), below which again is
clay (2 inches). On another face, half way between these two, the
sands have increased to 2 feet 8 inches, and the bottom clay
has disappeared. These facts illustrate the rapid variation in
these beds.

The " Lower Greensand " is shown on the Survey map as
overlapped by the Gault where this runs out along the ridge
followed by the main road from London to Oxford ; but descend-
ing from this ridge along the footpath by Trindal's Farm, a little
below the 300 feet contour, one finds a most distinct outcrop of
coarse pebbly sand, exactly like that seen on the other side of the
ridge. There is much Drift about here, and I could not recognise
this sandy outcrop by Chilworth Farm. Still, the " Lower Green-
sand " certainly extends beyond the limit marked on the Survey
map, and this suggests the possibility that it may follow the Gault
outcrop continuously round by Long Ground Farm. I have
ventured to mark it as continuous on Fig. i, though I have not
actually traced it.

On the other side of the ridge it can be traced pretty con-
tinuously from Sandy Lane (south of Tiddington Station) by
Tiddington village and Albury to near Rycote Pond. All along
this line it rests on the Kimeridge Clay, and springs mark the
boundary at Tiddington and Rycote. Beyond this latter point I
have not traced it. According to the one-inch geological map and
explanatory memoir there is a continuous narrow outcrop, largely
concealed by Drift, from here to beyond Thame ; but the new
Index Map shows it as ending at Rycote. If the former were
correct, " Lower Greensand " ought to have been shown in the
railway-cutting near Rycote Pond described by Mr. Codrington ;

THE GEOLOGY OF THE THAME VALLEY. 53

but that showed river-gravels resting directly on Kimeridge Clay,
Rycote Pond itself, a large sheet of water covered largely by weeds
and haunted by wild fowl, certainly rests on clay — Gault, accord-
ing to the one-inch map, Kimeridge, according to the Index Map.
I mention this to show the difficulties of mapping in this area,
where nothing seems to intervene between two great clays, where
Drift is plentiful, and exposures few.

Correlation of the *' Lower Greensand."

Just beyond the north-eastern boundary of the Thame Valley
the continuous outcrop of the marine Woburn Sands begins
Just at its south-western limit, the marine Toot Baldon sands
appear. In the intervening area, in association with the presence
of higher Jurassic beds than in adjoining areas, wc find an absence
of the continuous Lower Cretaceous beds, and instead we have
an irr^;ular series of patches, some marine, some freshwater.

Do the marine and the freshwater beds in the area represent
simply two facies of beds of the same age, such as we might get
in a large estuary ? or are there here two or more formations of
different ages ? In favour of the former view is the absence of
any section showing the freshwater beds overlain by unconform-
able marine beds ; but did such a section exist, it might easily be
taken, in the absence of fossils, as showing merely a contempo-
raneous erosion. Indeed, the section at the Windmill, Stone,
might very well be so interpreted but for the occurrence of marine
fossils at the very base of the sands not far off.

In favour of the second view, we have Morris's derived blocks
with freshwater fossils. But these might be derived from some
freshwater deposit of earlier date than the Shotover beds. There
is also the close approach of the Toot Baldon sands to the neigh-
bourhood of the Shotover beds, without any sign of passage
between them ; but against this must be put the absence at Toot
Baldon itself of any sign of littoral conditions and derived blocks,
such as we might expect if the sea in which they were deposited
was attacking a shore-line only a mile away.

There is one other point to be considered. As our President
(Mr. Teall) long ago pointed out, the freshwater beds always rest
on Portland or Purbeck, while the marine ones may rest on lower
beds. The only possible exception to this (now that the supposed
overstep at Wheatley is disposed of) is the outlier at Forest Hill,
and it is not impossible that the sands there may be marine. If
this distinction holds good, it suggests that the Shotover beds are
earlier in date than the earth-movements which gently folded
the Portland beds and led to the Gault overstep.

I incline, on the whole, then, to the view that the Shotover beds
are earlier in date than the marine beds. Of these, the Toot

A. H. DAVIES ON

THE GEOLOGY OF THE THAME VALLEY. 55

Baldon beds on the one hand, and the Wobum sands on the
other, represent, on the whole, less littoral conditions than the
Bishopstone beds, but the three may be of the same date. In
Aptian times, when the sea reinvaded this area, the Portland beds,
bent into a gentle basin with subsidiary N.W. to S.E. flexures, may
have formed at first an isthmus, uniting the land of London with that
of the north-west Marine erosion may have reduced this to a
peninsula, or an island, or a group of islands ; and the Bishop-
stone beds may have been deposited in the inlets made by the con-
quering sea along the anticlinals of the land. But the final conquest
came not by destruction, but by submergence. As the land sank,
the formation of littoral deposits became less and less important,
until finally, in the time of Hoplites interruptus, the Gault sea
spread its blue mud directly on the older rocks — though the
abundance of phosphatic nodules indicates a period of unrest at
first.

v.— GAULT.

I shall dismiss the Gault in a few words, as I propose to deal
with certain questions relating to it in a separate paper. The
main outcrop can be traced from the Aylesbury district to
Culham on the Thames. There are not many exposures, but
where the base is seen it belongs to the zone of Hoplites
interruptus^ as at Folkestone.

Supposed Outlier at Haddenham Low. — Besides the outlier at
Long Crendon (see p. 22 and Plate II.), two others are marked on
the Survey maps as resting on the outlier of " Lower Greensand "
(Bishopstone beds) that extends from near Haddenham to near
Upton. The larger and more northerly of these is shown as overlap-
ping the Lower Greensand, so as to rest on Portland Stone for a
distance of nearly three-quarters of a mile. In the explanatory
memoir to Sheet 45 it is stated that Gault is shown at the Kiln
(Haddenham Low).

Of the smaller of the two outliers I cannot speak positively,
but I have traversed the greater part of the ground occupied by
the larger one, and am convinced that it has no existence. The
clay exposed at Haddenham Low is a very sandy clay, exactly like
that of the Windmill section at Stone. On washing, it leaves an
enormous residue of pure white sand, without either foraminifera,
glauconite-grains, or /noceramus-prismSy such as abound in the
true Gault of Long Crendon. I have no doubt whatever that
this is the uppermost sandy clay of the Bishopstone beds.

In the portion of the supposed Gault which overlaps the
Lower Greensand and rests directly on the Portland, the King's
Cross pit (p. 40) has been opened, and we can see that what was
taken for Gault here is really Purbeck clay. Over the area south of
the Haddenham Low brick-kiln I could find no sign of clay at all;

S6 A. M. DAVIES ON

everywhere the soil was that typical of the ferruginous sands of
the Bishopstone beds.

My interpretation of the area is given in the sketch-maqp,
p. 54. I make no claim to having traced the boundary-
lines over the actual ground. They were drawn in consideration
of a large number of scattered observations, and several traverses
in different directions, and with the assistance of the contour-
lines. The lines drawn for the Purbeck and Bishopstone beds
north of the Dadbrook valley are purely hypothetical, so far as I
am concerned, as they were drawn in accordance with the published
Survey map and the run of the contour-lines.

After I had come to my own conclusion as to the non-
existence of Gault in this area, I noticed that the outlier in
question is omitted from the Index Map, Sheet 1 2. It appears,
however, on the International Geological Map of Europe,
Sheet B4, just published. In the explanation of Horizontal
Section, Sheet 140, Mr. Jukes-Browne speaks of the clay exposed
at Haddenham Low as belonging to the Lower Greensand. The
Index Map, however, shows Lower Greensand as resting on the
Portland west of King's Cross, in the area really occupied by
Purbeck.*

VI.— PHYSIOGRAPHY OF THE DISTRICT.

It is necessary now to consider the origin of the peculiar
course of the Thame in relation to the Portland and Gault
(see pp. 17 and 35 ). This course appears to me to confirm
the view of Prof. W. M. Davis, that the rivers of Eastern England
are in the mature stage of a second cycle of activity. The clue to
the puzzling course of the Thame is, I suggest, to be found in the
fact that, though its course at present is mainly on Kimeridge
Clay, it is properly a Gault stream. Before the last geocratic
movement by which the English rivers were rejuvenated, the
Thame meandered on a plain of Gault, some way to the north-
west of its present course, and at a considerably higher
level (250 to 300 feet). Its valley was bounded to the
north-west by the rise of the ground towards a low escarpment
of Portland beds and " Lower Greensand," which ran from Shot-
over Hill north-eastwards to Muswell Hill, and then gradually
curved eastwards with the strike, to Quainton, Oving, and Cub-
lington, where it died down as the Cretaceous overstep was com-
pleted. Whether this escarpment was actually continuous for the
whole distance is difficult to say ; the break in continuity of the
present Portland outcrop between Hazeley and Thame suggests, but

• Al the meeting at which this paper was read, the President announced^ that Mr. Jukes-
Browne had recognised the non-exisience of this Gault outlier when he revised the mapping
in 1887.

ves net zr:vcL i c-^rrtizsvcncdiv^ di sap ucu rail cl* .11 -iic jsvarpiiiciu
bttween Shctover and MuswelT Hills. If it did not complettily
die sway betweoi diese points^ it may have been lowia', owing
to die Portiand bedB being dmrner, or it may have beei recessed
far aooie ^fegtaw^ wtdt die dainge of strike caused by the
pMCredceooa anttdine which led to the bieak in the main

When die second c^de ai demicbtion begim^ the rejuvenated
Tbanie lapidLy cut its bed down^ while at the same time it shifted
imrif asa whole in the (firection of the dip of the Gault But
tke fiofmer action was more powerful than the lattec, and soon the
had cut through the cover of Gault and struck upon the
rocks benea^. The curves in which it had been
now hiwame fised* and at the same time the dipward
J was checked^ owing to the harder character of the rocks
k now had to erode. But at the two eids of the stream^ where
DO FoftiBDd bedi underlie die Goult, the dipward shifting con-
tiBoed, and tfaos the whole stream came to be drawn out into a
loop — hrghrming and enxfing on Gauit^ and cutdng down through
' Greensand and Portland beds to Kimeridge Clay in the

Mcaowhde die Pdrdand escarpment had suffered attack from
both sides^ bj die tributanes of the Ray as well as those of the
Thame. Bemg capped by such a thin layer of harder beds» it
readi^ yielded to die attafC^ and became cut up into isolated
oodien^ die Thame basin gaining on that of the Ray between
Shotover and Muswdl HiH, and still more strikingly between
Oving and Cublington ; whOe the Ray gained ground between
Muswdl Hin and Quadnton. Hence comes the irregularity o£
the north-western boundary, pointed out at the beginning. That
in ShoCover, Moswdl, Qoainton, and Ovin^ Hills we have dis-
integrated parts of an escarpment seems clearly shown ( i ) by the
ooiformity of their structure — everywhere capped by Lower
Greensand, never by Gault, as is the di£krently-produced oudier
of Long Crendon ; (2) by their disposition along a cur^-ing line of
strike ; (3) by the gradnad drop in the height from Quainton to
the vanishing point at Coblii^on, which was so low that here
abne facial drift obtained entrance into the Thame valley ; and
(4) by the fiat-topped character of the largest of them, viz.,
Shotover and Oving oudiers.

I expect and hope that these views, as well as others put
forward in this paper, may meet with criticism ; and I trust that
before long the members of the Association will have an oppor-
^xuiitj of discussing matters with me on the actual ground.

58 A. M. DAVIES ON THE GEOLOGY OF THE THAME VALLEY.

REMARKS UPON THE OSTRACODA.

By F. CHAPMAN. A.L.S.. F.R.M.S.

The majority of the Ostracoda here noticed are well-known Lower
Purbeck forms.*

There are, however, some other species of much interest, wfaidi
call for special comment.

Bythocypris winwoodiana^ Jones and Sherbom ; Proc, Baik
N, H. and Antiq. R Club, 1888, vol. vi, No. 3, p. 252, pi. V,
figs. I a-c.

This species was originally described from the blue FuUer's-
Earth Clay of Midford. A single specimen is here recorded, from
a green clay of uncertain horizon, but probably Portlandian,
at Denham Hill Farm, near Quainton.

Macrocypris horatiana, Jones and Sherborn ; Proc. Bath
N, H, and Antig. F. Club, 1888, vol. vi, No. 3, p. 252, pL V,
figs. 2 a-c.

It is interesting to note the occurrence of this species as
being in some abundance in the Aylesbury district, having been
previously found in the blue Fuller's-Earth Clay at Midford.

M, horatiana is here recorded from King^s Cross, Bed No. 3,
at the bottom ; and from a pit | mile from Walton (Aylesbury)
along Bishopstone footpath, Bed 4.

Cy there drupacea^ Jones; Quart, Journ, GeoL Soc, 1884,
vol. xl, p. 772, pi. XXXIV, fig. 30. Cytheropteron drupaceum
(Jones), Chapman, 1894, ibid. ; vol. 1, p. 691. Cy there drupacea
(Jones), Chapman, 1897 ; Proc. Geol. Assoc , vol. xv, p. 96.

This species has been found in the Great Oolite of the
Richmond Well-boring, in the Hartwell Clay of Aylesbury, and in
the Bargate beds (Aptian) of Guildford [perhaps derived].

Some of the Jurassic examples from the Aylesbury district
now under examination are exceptionally tumid in the postero-
ventral region. Cythere drupacea occurs in all the samples from
King's Cross, Bed No. 3, and in some abundance.

Cytheridea (?) subeminula, Jones and Sherborn ; Proc. Bath
N. H. and Antig. F. Club. 1888, vol. vi, No. 3, p. 261, pi. V,
figs. 8 a~c.

A specimen from Coney Hill, Bed 5, agrees somewhat nearly
with the above species, but being slightly damaged it is difficult
to say with certainty. Messrs. Jones and Sherborn described this
species from the base of the Fuller's-Earth Oolite between Not-
grove and Bourton.

* See T. R. Jones, Quart. Journ. Geol. Soc., vol. xli, 1885. p. 311 ; also F. Chapman,
Proc. GeoL Assoc. ^ vol. xv, 1897, p. 96.

^**-ii

..^ -•'£'*

58 A. M. DAVIES ON THE GEOLOGY OF THE THAME VALLKY.

REMARKS UPON THE OSTRACODA.

Bv F. CHAPMAN. A.L.S., F.R.M.S.

The majority of the Ostracoda here noticed are well-known Lower
Purbeck forms.*

There are, however, some other species of much interesti whidi
call for special comment.

Byihocypris winwaodiana^ Jones and Sherbom ; Proc. BaA
J\r. H. and Antiq. R Club, 1888, vol. vi, No. 3, p. 252, pi. V,
figs. I a-^.

This species was originally described from the blue FuUer't-
Earth Clay of Midford. A single specimen is here recorded, from
a green clay of uncertain horizon, but probably PortlandiaOi
at Denham Hill Farm, near Quainton.

Macrocypris horatiana, Jones and Sherborn ; Proc, BaA
N. ff, and Antiq. F. Club, 1888, vol. vi. No. 3, p. 252, pi. V,
figs. 2 a-c.

It is interesting to note the occurrence of this species as
being in some abundance in the Aylesbury district, having been
previously found in the blue Fuller's-Earth Clay at Midford.

M, horatiana is here recorded from King's Cross, Bed No. 3,
at the bottom ; and from a pit f mile from Walton (Aylesbury)
along Bishopstone footpath, Bed 4.

Cy there drupacea^ Jones; Quart. Journ, GeoL Soc,, 18841
vol. xl, p. 772, pi. XXXIV, fig. 30. CytJieropteron drupaceum
(Jones), Chapman, 1894, ibid, ; vol. 1, p. 691. Cy there drupacea
(Jones), Chapman, 1897 ; Proc. Geo!. Assoc , vol. xv, p. 96.

This species has been found in the Great Oolite of the
Richmond Well-boring, in the Hartwell Clay of Aylesbury, and in
the Bargate beds (Aptian) of Guildford [perhaps derived].

Cytheridea (?) subeminula, Jones and Sherborn ; Proc. Bath
N. H. and Antiq. F. Club. 1888, vol. vi, No. 3, p. 261, pi. V,
figs. 8 a~c.

* See T. R. Jones, Quart. Journ. Geol. Soc., vol. xH, 1885. p. 311 ; also F. Chapman,
Proc. GeoL Assoc^ vol. xv, 1897, p. 96.

Plate II.

cs STONE & HARTWELL

^se*nJ

:£t

Jt^t

X'am.fv.

J. -J

^ rtJt

a/S^ORSTOf^iC

acoz

B£:i>S

CTay

B£^OS

ci^Ayf

S«ale : r inch = 20 fc*r.

ORDINARY MEETING.

Friday, November 4TH, 1898.

J. J. H. TEAL^ M.A., F.R.S., President, in the Chair.

The following were elected Members of the Association : G.
Reeve, jun., John Theodore Hewitt, M.A., etc.

The evening was then devoted to a Conversazione, and the
following is a list of the exhibitors and their exhibits :

The President : Specimens illustrating the artificial production of the
structures of Gneissose rocks by the deformation of heterogeneous masses
of clay, and photog^phs of similar structures in the Gneissose rocks of
the Lizard Peninsula ; Sections of artificial rocks and minerals prepared
by Messrs. Fouqu^ and Ldvv ; Micro- photographs of woUastonite-spheru-
lites in bottle glass ; and Puttes to illustrate the Memoir on the Silurian
Rocks of Scotland, by Messrs. B. N. Peach and John Home.
H. W. Burrows and R. Holland : A large series of photo-micrographs of

recent and fossil Foraminifera.
The Director-General of the Geological Survey : Recently issued

Maps and Memoirs of the Geological Survey.
J. Slade : Specimens of wavellite from Barnstaple.
Horace B. Woodward : An old print from a drawing by De la Eeche, and

a representation of Dr. Buckland, diawn by Thomas Sopwith.
J. n. Hardy : Objects shown under the microscope by the aid of the

exhibitor's " Chromatoscope."
E. T. Newton : A new Dinosaurian from the Rhactic of Glamorganshire,

found by John David ; and a series of forged flint implements.
W. P. D. Stebbing : A copy of " Meteorologia et Oryctographia Helvetica,"
by J oh. Jacob Scheuchzer, Zurich, 1718, with folding plates; specimen
of Bryozoa Bed, Lower Limestone Shales, Portisheaa ; Hyolite Lime-
stone from the Lower Cambrian of Nuneaton ; and silicified wood from
Edmonton, N.W. Canada.
Prof. T. G. Bonney : .Apatite and associated rocks from Canada.
Miss C. A. Raisin : Rock specimens from Switzerland and from the

Vosges.
George Potter : Some of the early circulars of the Association, including
the first circular issued ; a portrait of Mr. Toulmin Smith, the first
President ; and some interesting old prints including a representation of
Dr. Bowcrbank's house in Highbury Grove. {The ahovt wert 0/ special
interest on this occasion, as the Association now completes the \oth year
of its existence, the first meeting having been held on the 17M November,
1858.)
G. E. DiBLEY : Some rare and undescribed fossils from the Chalk.
John N. Tervet : A fossil Fish from the Oil Shales of Sao Paulo, Brazil ;
fossils from the Oil Shales of Australia, and from Tarbrax, Lanarkshire.
Rev. Prof. J. F. Blake : A fine collection of Jurassic Ammonites from

Russia and from India.
Percv Emary : Specimens and micro-sections of rocks from the Urals.
F. R. B. Williams : A series of fossils from Hythe and neighbourhood.
W. F. Gwinnell : Large land Mammals dreclged from the Dogger Bank in
the North Sea, including remains of Mammoth, Reindeer, and Bos
primigenius ; Nummulites and nummulitic limestones from the Isle of
Wight, Belgium, Malta, Egypt, and India, including some exceptionally
large specimens.
Febru.ary, 1899.]

6o PROCEEDINGS.

S. Hazzledine Warren : A series of flint implements from the Thames
and Lea Valleys, including examples of Eolithic or Plateau type, and of
the Earlier, Middle, and I^ter Palaeolithic forms.

A. E. Salter : Specimens (other than flint) illustrating the constitution of
the gravels of the Early Drifts of the South and East of England.

F. A. Bather : Specimens, plaster casts, and drawings of Fttalocrinus from

the Silurian Rocks of Iowa and Gotland, being a large part of the material

described in the Quarterly Journal of thi Geological Society^ vol. liv, pp.

401-441, Pis. XXV and XXVI, August, 1898.
A. S. Kennard : Palaeolithic Implements from West Wickham, Kent.
Benjamin Harrison : A series of Plateau and Palaeolithic Implements

arranged to show the persistencv of the types.
Frank Lash am : Palaeolithic Implements from Famham, Surrey.
D. A. Louis : Iron ores and associated rocks from Kiiranavara and Geliivara,

Lapland; photographs showing the character of that country and of the

deposits and modes of working them ; specimens of iron ores from

Pcrsberg, Central Sweden, and of the metal produced from them.
J. HOPKINSON : Sections of Mount Sorrel granite, garnetiferous gneiss from

Perth, and Hebridian gneiss from Hannan Islands, shown in polarised

light under the microscope,
Martin A. C. Hinton : Remains of a fossil horse {Equus caballus) from the

High Terrace Gravel of Wanstead ; ard samples of psilomelane found in

a continuous seam at the same place.

G. Fletcher Brown : Fossils from the Chalk and London Clay.
J. Francis: A collection of Jurassic fossils from Whitby.

G. Abbott : Segregation in mortar, honeycomb limestone, and concretions,
spherical flints with kernels, and ripple marks in limestone.

R. Elliott : A case containing Hugh Miller's favourite hammer ; and fossil
fish from the Old Red Sandstone ; flint implements from Canada und
Tasmania ; specimens from a Saxon interment in Suffolk ; tooth of
Elephas primigenius and a fine specimen of Ftychodus.

Upfield Green : Skiagraph of crinoids in slate ; folded purple slates,
brecciated slates, and ash beds from Cornwall ; a large quartz crystal
built up of smaller ones from Eiserfeld, near Siegen ; fractured and re-
cemented apatite crystal from Norway ; and contorted gneiss from
Septimer Pass, Casaccia, Engadine.

ORDINARY MEETING.

Friday, December 2nd, 1898.

J. J. H. TEAL^ M.A., F.R.S., President, in the Chair.

The following were elected members of the Association:
W. H. Cooke, B.A., Ellis W. Heaton, Henry Hendriks,
H. Kidner, H. J. Leaning, and J. M. V. Money-Kent.

A paper was read by Mr. A. Morley Davies, A.R.C.S., B.Sc,
F.G.S., entitled "Contributions to the Geology of the Thame
Valley." The paper was illustrated by maps, sections, and
specimens, and by some excellent photographs taken by Mr. J. H.
Pledge. By the kindness of Prof. Bonney, a series of fossils
collected from the district by the late Prof. Morris was also
exhibited.

THE NATURAL HISTORY OF CORDIERITE
AND ITS ASSOCIATES.

By J. J. H. TEALL, M.A., F.R.S., F.G.S.
{Presidtntial Addrtu^ delwtrtd Februaty jrdf iS^g.)

DURING the last thirty years an extraordinary outburst of
petrological activity has taken place in consequence of
the application of precise mineralogical methods to the study of
rocks. The petrologist, and through him the geologist, owes
therefore, an enormous debt of gratitude to the mineralogist ; but
while acknowledging this debt, I desire to point out that the
benefits, due to the more intimate union between geology and
mineralogy which has thus been established, are not wholly one-
sided. If petrology owes much to mineralogy, it has in its turn
conferred benefits upon the latter science. Striking evidence of
this is furnished by the important work on the mineralogy of
France and her Colonies by Professor Lacroix, who is not only a
mineralogist but a distinguished petrographer and geologist.
This book, unlike the older mineralogies, is not a mere catalogue
of the crystallographic, chemical, and optical characters of museum
-specimens, but a series of monographs in which the different
minerals are treated from all points of view, and in which due
importance is attached to their modes of occurrence and origin.
This welcome change is, it seems to me, largely due to the
influence of petrology upon mineralogy.

Let me try to illustrate the advantage of studying minerals
from what may perhaps be termed the natural history point of
view, by giving some account of a small group which has attracted
roy attention at intervals during the last few years. I refer to the
^* faithful companions " — corundum, spinelle, sillimanite, and
cordierite.

Corundum is crystallised alumina (Al.O,) and is therefore the
-simplest of the four in composition. Its crystals belong to the
hexagonal or rhombohedral system, and vary in habit and
colour according to their mode of occurrence. Many beautiful
gems such as ruby and sapphire are merely varieties of
corundum.

True spinelle is an aluminate of magnesia (MgOjAljO^), and,
like all the members of the group, crystallises in the cubic
system in the form of octahedra. Between true spinelle and
magnetite (FeO,Fe.,03) there are many intermediate varieties in
which ferrous iron takes the place of magnesium and ferric iron
that of aluminium in almost any proportion ; so that the general
fomiula for the group, excluding the chrome-spinelles, to which I
May, 1899] 5

62 J. J. H. TEALL ON

do not propose to refer, may be written (MgFe)0,(Al2Fej)0»
These intermediate forms are usually green in colour, the depth
of tint increasing to opacity as the amount of iron increases.
As it is impossible to distinguish different varieties, such as
pleonaste and hercynite, under the microscope they will simply
be referred to as green spinelles.

Sillimanite is the simple silicate of alumina (Al^Os, SiO,).
It crystallises in the rhombic system as long slender prisms,
which are often so thin as to appear like needles or hairs under
the microscope.

Cordierite is a silicate of alumina and magnesia with some
iron replacing the magnesium (2MgO,2Alj03,5Si02). It may be
said to bear the same relation to spinelle that sillimanite does to
corundum. Thus sillimanite is corundum plus silica; and
cordierite is spinelle plus silica. Cordierite crystallises in the
orthorhombic system, and is found under two conditions. In the
gneisses and contact-rocks it occurs, as a rule, in irregular
colourless grains which are not pleochroic in thin sections,
except a round minute inclusions of zircon. In this form it is
often crowded with needles of sillimanite, and not infrequently
contains also small and more or less rounded scales of biotite.

In volcanic rocks it often occurs as six-sided prisms, cross
sections of which break up into sectors in polarised light. There
is thus a marked difference in habit between the cordierite of the
gneisses and contact-rocks, on the one hand, and that of the
volcanic locks on the other. The cordierite of the volcanic rocks
is, moreover, often pleochroic.

Now these minerals, usually in combinations of two or
more, occur under the most diverse geological conditions. They
are found :

1. As the constituents of foliated crystalline rocks belonging
to the so-called Archaean formation.

2. As the products of contact-metamorphism round plutonic
masses.

3. As the constituents of inclusions in (a) plutonic igneous
rocks, (d) dykes, and (c) volcanic rocks, including both lavas and
agglomerates.

4. As the direct products of the crystallisation of natural
silicate-magmas.

5. As the direct products of the crystallisation of artificial
silicate-magmas.

It is impossible within the limits of this address to do more
than refer to one or two typical examples of each of these modes
of occurrence.

Cordierite-gneisses are found in many parts of the world in
association with other foliated crystalline rocks, and also not
infrequently in the neighbourhood of granites containing
cordierite into which they are said to pass. Bodenmais, in

CORDIERTTE AND ITS ASSOCL\TES.

Bavaiia, is one of the best known localities. Here cordierite
occurs in connection with sillimanite, biotite, quairtz, iron-ores,
garnet, and sometimes also with orthodase and oligoclase. The
siUimanite may be either crowded together in clots or bundles^
or may occur as inclusions in the cordierite, and sometimes also
in the other minerals. The cordierite is irregular in form and
colourless, with yellow pleochroic halos round zircons ; but it
does not show the division into sectors or the pleochroism
which are so characteristic of the cordierite of volcanic rocks.

Similar rocks occur in the granulite region of Saxony, at
Tvedstrand in Norway, in the Central Plateau of France, and
many other localities.

Various views have been expressed as to their origin. Some
are content simply to refer them to the Archaean system ; others
r^ard them as due to the contact or thermo-dynamic metamor-
phism of ordinary argillaceous sediments ; and others as rocks
of mixed origin, that is as rocks containing both igneous and
sedimentary material.

The last view, although it is certainly not applicable to all
cases, deserves more than a passing notice, for where cordierite-
bearing rocks occur as contact products they usually belong to
the inner zones and sometimes give distinct evidence of the
intimate intermixture of granitic and sedimentary material If
mixed rocks of this kind were foliated by deformation they would
unquestionably produce cordierite-gneisses.

Cordierite-bearing rocks, often containing siUimanite and
spinelle, have been recognised at many points in the Eastern
Highlands in the counties of Aberdeen, Banff, and Forfar. A
general account of these rocks was given in the Explanation to
Sheet 75. I will quote a description of a specimen from the top
of the Buck of Cabrach collected by Mr. Hinxman.

''This is a massive, dark, bluish rock spangled with small flakes
of white mica. It possesses a somewhat spotted appearance in
consequence of the presence of individuals or aggregates of
cordierite. The colourless constituents, cordierite, andalusite,
white mica, microcline and quartz, make up the main mass of the
rock. The dark minerals are magnetite and biotite, but the
latter is very feebly represented. Cordierite, andalusite and
white mica usually contain numerous inclusions of magnetite and
quartz and thus show the micropoikilitic structure which is so
common in contact minerals. All the massive cordierite-bearing
rocks show a characteristic bluish-grey colour, but they vary in
composition. A specimen from the railway cutting southeast of
Little Amage is of considerable interest as throwing light on a
subject I have already referred to. It is evidently a compound
rock due to the superposition of igneous upon metamorphic
material. The igneous portion is represented by more or less
idiomorphic oligoclase, biotite, orthoclase and quartz; the

64 J. J. H. TEALL ON

metamorphic portion by cordierite, quartz, biolite, sillimanite,
iron ores and a green spinelle. The rock into which the granitic
magma was intruded is now represented by somewhat ill-defined
shreds, patches, and streaks in a paste of igneous origin."

Since the Explanation of Sheet 75 was published other
specimens of the same type of rock have been sent up for exam-
ination by Mr. Barrow and Mr. Kynaston. Mr. Barrow's
specimens were collected in the Glen Muich area, and one of
these, composed of cordierite, sillimanite, quartz, biotite, iron-ores,
green spinelle, and probably a little felspar, was analysed. It
contained, as might naturally be inferred from its mineralogical
composition, a very high percentage (32*4) of alumina. Mr.
Barrow looks upon the rock as the result of the general thermo-
metamorphism which has affected the Eastern Highlands and
which was associated with the intrusion of the earlier granitic
material. Mr. Kynaston's specimens come from the neighbour-
hood of the Ben Cruachan granite and are regarded by him as
normal contact-rocks due to this mass of granite. They are
medium grained, dark, bluish grey, fairly massive rocks, composed
of cordierite, andalusite, alkali-felspar, oligoclase, biotite, pyrite,
and a green spinelle. Quartz is sometimes, but not alwaj^,
present.

In describing rocks of this type from the Eastern Highlands,
I have more than once called attention to the fact that corundum
might naturally be expected to occur in them, but that it could
not be detected in the thin sections. The presence of a colourless
grain which might possibly be corundum in one of the slides of a
specimen from the neighbourhood of Ben Cruachan led me to
examine the rock in another way. The coarse powder was placed
in hydrofluoric acid and allowed to digest for several days, with
the result that corundum was found in the residue together with
pyrite, spinelle, and a few crystals of rutile that had escaped notice
in the slide.

The corundum in this rock occurs in crystals and more or
less irregular grains. The crystals are combinations of the
hexagonal prism, the primitive rhombohedron, and the basal
plane. They are sometimes flat and sometimes prismatic. The
flat forms in which the prism is feebly developed are frequently
stepped on the basal plain owing to the repeated alternations of
this face with the faces of a rhon\lbohedron. This habit is not
unfrequent in corundums. It may be seen in some of the Burma
rubies and is a marked feature of the Montana " sapphires."

A very interesting case of the occurrence of all four minerals
in rocks produced by contact-metamorphism has been described
by Salomon^^**.* The important mountain mass of which Monte
Adamello (11,681 ft.) forms the culminating point is situated in
the southern portion of the Eastern Alps. It consists of a nucleus

*The small figures refer to the list of papers quoted at the end of the Addres

CCOLIXSRITE AXO ITS Jl£SSOCL\'nES^ O5

of tacaaSae or ^sut^^Saanlo^ sanoanded br a giidte of sedimec^
tnr lodks of ^&Kat ages., mam j of which s^ov the effects of

Tbe rocks vica which w« are more immediately concerned
form part of a asoe foOowirrg the western margin of the intrusive
mass^ akng which ther have been traced for a distaince of fourteen
kikKMCticv TIkt represent portions of the older, more or less
mnamorpbosed sedimentary rocks of the Alps which have been
stin fizrther metamorphosed by the tonalite. The most charac^
terisdc rock of the inner rone consists of fifty^ or very often ot^
sixty or seventy per cenL of cordierite associated with various
other minerals* including btotite, andaiusitc, sillimanite* quarte»
dtanileroos iron-ore, and, in certain special cases» pIagioclase»
ofthodase, garnet, spinelle» and corundum. There is olten a
most intimate association of the cordierite-bearing contactrock
and the igneoos mass« and inclusions of the former occur in
the latter.

So much for contact-rodcs. We pass on now to consider
other modes of occurrence. Inclusions containing two or more
of the minerals in question, sometimes all four together, are found
in plutonic masses, dykes^ lavas, and agglomerates. They occur,
for example, in the tonalite, to which I have just referred, iti the
kersantite dyke of Michaebtein in the Hartz'**, in andesitic
lavas of the EifeP**, the Siebengebirge'*, and the province of
Almeria, in the south - east of Spain*^^ ; and, finally, in the
ejected blocks of the Laacher See and of Asama Yama in
Japan**. By piecing together the evidence furnished by different
localities we seem to be able to trace these inclusions from their
birthplace in the infernal regions to their final resting-place on
the earth's surface. The subterranean nuigmas act powerfully on
their containing walls, and transform highly argillaceous sediments
into crystalline rocks composed of cordierite, sillimanite, biotite,
quartz, and sometimes spinel le and corundum. The rocks of the
inner contact-zone become shattered, and the igneous magma
insinuates itself between the cracks, or may even permeate the
mass. Portions of the metamorphic rock float off into the molten
material and travel with it through dykes and other channels to
the surface, where they form either inclusions in a lava or ejected
blocks in an agglomerate, according to the conditions of the
eruption. This, no doubt, is the explanation of the presence of
inclusions containing the minerals m question in some cases, but
it by no means supplies a full explanation of all the facts. Many
of the inclusions, especially those found in dykes, lavas, and
agglomerates, resemble fragments of cordierite-gncisses rather than
normal contact rocks ; others contain the minerals in a form
different ifrom that in which they occur either in the gneisses or
the contact-rocks. To illustrate these points we must consider
one or two typical cases.

66 J. J. H. TEALL ON

The kersantite - dyke, near Michaelstein^*', is intrusive in
clay -slate with subordinate layers of limestone, quartzite and
kiesel-schiefer. The rock, which is dark-grey, almost black in
colour, is composed of numerous phenocrysts of biotite and a
few of felspar, set in a compact matrix. Under the microscope
enstatite and cordierite may be recognised, and the latter mineral
occurs in such a way as to prove that it must have crystallised
from the magma. It forms sharply defined six-sided prisms,
cross sections break up in polarised light into sectors — often
six — and opposite sectors extinguish simultaneously. These
features are not those of the cordierite of the gneisses or contact-
rocks, and they undoubtedly prove that the mineral has been
formed where we now see it. But the occurrence of authigenic
cordierite is by no means the only peculiar feature of this
remarkable dyke. It is crowded with minerals which are
obviously foreign to the rock, including felspar, garnet, sillimanite,
cyanite, quartz, biotite, rutile, spinelle, apatite, corundum,
staurolite, hypersthene, calcite, magnetite, anatase, and titani-
ferous iron-mica, 'i'hey occur either singly or in aggregates.
Scarcely a slide or specimen can be found without one or more
of them, and the aggregates vary from microscopic dimensions up
to the size of a walnut, or even larger. In some cases half the
rock is made up of foreign constituents.

Before dealing with the significance of these facts, let us
consider one or two other cases of an allied nature. The hom-
blende-andesites of Bochsberg and Rengersfeld in the Eifel,
described by Vogelsang*"', are not homogeneous in character.
They contain masses which sometimes have the aspect of
included fragments and sometimes that of streaks merely differing
in character from the rest of the rock. The minerals of which
these aggregates are composed are cordierite, andalusite, silli-
manite, felspar, biotite, pleonaste, corundum, rutile, quartz,
garnet, zircon, and magnetite — that is much the same association
as that found in the foreign substances in the Michaelstein dyke.
The aggregates, which are formed of somewhat variable combina-
tions of the minerals I have mentioned, are sometimes easily
separable from the natrix, at other times firmly welded to it.
They vary in size from microscopic dimensions up to masses
6 cms. in diameter, or in the case of the streaks 12 cms. in
length.

A very common type consists of a fine-grained, grey rock,
essentially composed of cordierite, andalusite, sillimanite, and
plagioclase. The cordierite is irregular in form, intensely pleo-
chroic, and often twinned. It contains grains of rutile, needles
of sillimanite, and inclusions of glass.

Andalusite is next to cordierite the most abundant con-
stituent. Sillimanite occurs in fibrous aggregates between the
other constituents, and also as inclusions within them. Biotite is

CORDIERITE AND ITS ASSOCIATES. 67

not uncommon, and is often found in association with a brown
amorphous substance which appears to have been formed by the
partial melting of the mineral. Pleonaste or green spiiielle
occurs in the inclusion, and is also found abundantly in well-
formed octahedra in the andesite immediately surrounding the
inclusion.

There can be no doubt that these inclusions have been
derived either from the crystalline schists or from a contact-zone.
Vogelsang, who has studied them in great detail, inclines to the
former view. The occurrence of spinelle in the andesite imme-
diately surrounding the inclusions is of special interest. This,
like the cordierite in the kersantite of Michaelstein, undoubtedly
owes its origin to the chemical change in the magma consequent
on the solution of a certain amount of the material of the
inclusions.

Another interesting case of a somewhat similar character
occurs in the province of Almeria, in Spain *"*. The south-east
coast of Spain, from Cabo di Gata to the neighbourhood of
Carthagena, a distance of about two hundred kilometres, is
bordered by a zone of volcanic rocks belonging to the upper
Miocene or early Pliocene periods. They are not continuously
exposed, but appear at intervals from beneath the upper Pliocene
deposits.

This zone of volcanic action bears the same relation to the
alpine folds of the mountains of Andalusia as do the volcanic
rocks of the northern coast of Africa to the corresponding folds
of the Atlas system, and as do the Tertiary volcanic rocks of
Italy to those of the Apennines.

A plain of upper Pliocene rocks separates the Sierra Alhamilla,
which belongs to the central zone, from the Sierra del Cabo di
Gau which is formed entirely of volancic rocks. On the northern
side of this plain are several small hills, one of which, Hoyazo,
has a curious crater-like depression in the centre. This depression
can be entered by following the course of a ravine which is about
200 yards long. The bottom of the depression is about 200 feet
below the rim, which is almost circular, and about 350 yards in
diameter. The lower part of the wall is formed of andesite and
andesitic tuffs, the upper part (6-13 ft.) of marine limestone
containing bivalves and gasteropods. In the upper part the
slope is steep, often vertical ; in the lower part, formed of the
volcanic rocks, it is less steep. The limestone forms a mantle to
the hill which was for a long time regarded as a typical crater of
elevation. There is, however, clear evidence that the limestone
was deposited on the igneous rocks, and that there has been no
volcanic action since its deposition.

The volcanic rock is a mica-andesite. It contains phenocrysts
of a basic plagioclase, biotite, rhoml)ic pyroxene, and hornblende
in a glassy base. But the most interesting constituent is

6&. J. J. H. TEALL ON

cordierite. This occurs in two forms — as irregularly bounded
optically uniform grains up to the size of a hazel-hut, and as
sharply defined idiomorphic crystals. The former are inclusions ;
the latter are crystals which have separated from the magma. In
addition to the mineral inclusions there are also rock fragments
varying in size from that of a head down to microscopic
dimensions. These are (i) quartz blocks, (2) lumps of quartz
and cordierite, and (3) fragments of cordierite-biotite-gneiss with
garnet.

Osann, whose description I am quoting, points out that the
extraordinary abundance of indigenous cordierite coupled with the
presence of numerous inclusions of cordierite-gneiss lead to the
conclusion that portions of the foreign rock have been dissolved
and that a magma of exceptional composition, out of which
cordierite has separated on cooling, has thus been formed.

We have now to consider the evidence furnished by ejected
blocks.

The volcano of the Laacher See, like that of Vesuvius, is
remarkable for the number and variety of the ejected blocks
occurring in the agglomerates. They include fragments of
crystalline foliated rocks, blocks mainly formed of sanidine, and
fragments of trachyte ; the two last being obviously connected
with the magma. Of the crystalline schists, cordierite-gneisses are
the most abundant. They occur in their normal condition, and
also show the effects of the great heat to which they have been
subjected during the eruption. Dittmar<^^ divides the cordierite-
bearing rocks into three classes: (i) cordierite-gneiss with
sillimanite, (2) massive rocks containing newly formed felspar
and cordierite, and (3) spotted schists.

In rocks of the first group, which show little or no alteration
by heat, the cordierite is clear, very slightly pleochroic, and con •
tains inclusions of spinelle and corundum. In rocks which have
been acted upon it is strongly pleochroic and mostly free from
sillimanite. It is also surrounded by a zone of glass, and con-
tains secondary glass-inclusions. The biotite in these rocks has
often been fused to a glass out of which spinelle has separated.
In still more highly altered rocks the original minerals have
entirely disappeared, and newly formed cordierite is seen lying in
a matrix of brown glass.

Many other cases of a similar character might be quoted, but
one must suffice. A basalt occurring near Kollnitz '^'* in Carinthia,.
has involved fragments of an argillaceous rock and partially
dissolved them. The normal basalt is composed of plagioclase,
augite, olivine and magnetite, and is almost holocrystalline. The
included fragments are associated with glassy streaks or sclilieren,
in which cordierite and spinelle have been formed. The partial
solution of the fragments evidently modified the composition of
the magma so that it cooled as a glass after cordierite and spinelle

had separated ooL Tht •sobj if :ihe sanf: ja ±Bt n&f liv die
ejected blocks of the ! garhrr Sul xbs: bh&sobs ^ Qjkbbo. jiii£
tbe Eifid, and tbe keansoatf: dv^ oif MiimatfiameiiL Sb iis ^lonr
interesting to note thai liie ark^Tnox ^r litimmxL 33/ ±e 'lairimr
magma has hindered its cyBE&IEisscaaaL I^is ^tfifegr ^of rimrnmi js
preventii^ crjstaBisalsooa s wcSl koistrx ia> £as»aBrib£cs.

Conmdmn has beta ncxri^eic s ^esamsif ix aimy
igneous rocks^ and in soame of i^jcse ii 3i Tmaannagtfly nifiignwani
Professor Lagorio,* who W2&. I iicisjfiwt, lae irat ai iniBac m iie
igneous origin of cuniiiinHiuiEu cfics iCBXf TTHTinnn^ :^i2C imdamint-
ately in several of these tibe aamifTai! ]bbs -iJcsaLmy oix tsrv^aaQiwd
out of tbe magma. Xcienbeiitsiw tPrcre: jare ikic a oew wsSl
authenticated cases : for eumpTie. tsie cormicnmrgiirTmgrces ami
corandum-sjenites of tibe Vrih '^ acnd rihtt vi^sj -*""*■ a ^tnii*^
corundum-syenites of HaigTW^ Cccascr. r^jmaffja s^sceodiT tf&a*-
covered by tbe GcoSogical Surrey id Hat Ixmmixm^ xmif adinijTabfy
described by Mr. M^kr. ^ l3s al rhiwe cases :£ie s&zcrtz of c&e
idiomorphic corundum is forroed cf aijka[iHJtdapar, scmec^eaes
associated with nephdine. Moreorer. ±e xjrruisrre rftarnh'-rrr of
the Canadian rocks is quite ckar.

Then, to come nearer home. f3awe s '^e meresm^ C2se
described by Professor Busz. = The 3l menl occira ia jl feimte;
intrusive in clay slates, near Swnh Brese. I: 5* preset: in atrcaieSy
minute tabular crystals ' 'oz-'o^mm j, sccieticiei shcv-zg hesigccdJ
outlines, and is most abundant near the occtacr of the aeisite wich
the clay slates. It is, no dccbc diae, xs Proreisor E'.iiz stares, to
the fact that portions of the slaies w*re diasciTed by ±^ feiaidc
magma, which became super-saiurated with 2liLsiiia, en cooiin ^
and thus gave rise to the formation of cr^rzz,dzm.

Another apparendy well-authenticared cue, is that of tbe so-
called Montana sapphires. The minerals were first found and
worked in an auriferous glacial gravel near the head waters of the
Missouri, but they were subsequently discovered by Mr. G.'^F.
Kuntz in an igneous rock which Prof. Miers described as a
vesicular mica-augite-andesite. Still later, corundum was found
near Yogo Gulch, fifteen miles south of Utica, in a yellow,
earthy material which could be traced across the country for a
considerable distance in an east and west direction, and which
evidently resulted from the alteration of an igneous dyke. In
working downwards the unaltered igneous rock was reached and
this has been descrilied by Prof. Pirsson as a basic lamprophyre,
consisting mainly of biotite and pyroxene. Speaking of the
relation of the corundum crysUls to the matrix Prof. Pirsson '^
says: "The clear-cut form of the crysUls and their general
distribution shows that they had crysuUised out of the magma
with as much certainty as th e well-formed phenocrysts of felspar
in a porphyry betray their origin." He explains the presence of
the mineral by supposing that the original magma dissolved

70 J. J. H. TEALL ON

portions of the " clay shales " of the district and thus, on cooling,
became supersaturated with alumina.

If Prof. Pirsson's theory be true we have here a case of the
formation of corundum in a basic magma containing lime-
magnesia silicates. As will be seen later on there are some
difficulties in the way of accepting this theory, but I am not sure
that they are sufficient to destroy the force of the facts recorded
by him.

We have now arrived at the last stage of our enquiry. A
recently-published paper by Dr. Morosewicz, '^" of Warsaw, gives
a complete or nearly complete account of the conditions under
which the four minerals (corundum, spinelle, sillimanite, and
cordierite) form in igneous rocks. The researches described io
this paper extended over a period of five or six years, and the
results obtained are, from a petrographical point of view, some of
the most interesting that have appeared during recent years.
They must rank in importance with the . artificial production of
igneous rocks by Messrs. Fouqu^ and L^vy.

The experiments were made in a Siemens' furnace in a glass
factory near Warsaw. In his attempts to make artificial rocks,
Dr. Morosewicz accidentally produced some more or less
crystalline masses extremely rich in corundum and spinelle.
This led him to determine the chemical conditions under which
these minerals had been formed.

He isolated and analysed them, and also ascertained the
composition of the mass which remained after they had separated
out, for they always belonged to the first period of consolidation.
He found that the ratio of the alumina-silicate bases (K2O, Na^O,
CaO) to the alumina, in what may be called the mother-liquor,
was very nearly 1:1. This is the ratio characteristic of the felspar
group, and the fact naturally suggested the conclusion that, when
alumina is present in excess of that given by this ratio, it is liable
to crystallise out m the form of corundum alone, of corundum
and spinelle, or of spinelle alone ; the amount of spinelle being
•determined by the amount of magnesia present.

He then proceeded to verify this conclusion by dissolving
alumina in artificial magmas corresponding to anorthite, nepheline,
albite, orthoclase, and to mixtures of these. The results were
completely in accordance with theory, except that a pure
orthoclase -magma was found, to his astonishment, to possess
little or no power of dissolving alumina. But this was not all.
One or two additional facts of great interest revealed themselves
during the progress of the research.

Alumina, in the form of bauxite^ was found to be soluble in
different proportions in the different magmas. Thus, in one case,
two mixtures were prepared ; one corresponding approximately to
anorthite with two per cent, of soda, another to nepheline with one
and a half per cent, of lime. To 2 1 2lbs. of the first, 5olbs. of

COROIERITE AND OS ^^SOCULTEE. JT

bauxite were added, and to die same amcnnt-^ifttie second. :ccxm^
of die same substance. In fanr aonrs uie Tpynef^ne Tiune
melted to a homogenous mass ;n die hoiftesi pair -;c use roznace
{about 1,30a deg. C;, but after npearr-fdiEr -mm ox: anccitnie
multure, under the same condtnons. ^iaa .xxxpesfiecrtr rased, a
considerable amount of aimnina resnaunng^ zndissotvuL Aner
cooling it was found that the nepheisne rmxtzzze ^«as ':rDiwded
with microlites and minute cryKais ^^tf' oonzndam ind nKoaeaat,
and that the anoithite mixtare rxmsamtd -Txrmes. .a wmca
beaudiui glistening crystals of coomidxmi liese assoc^axed «itii
onmelted grains of aiununa. The ncpiKSxne :nmme zoauaatd
295 per cent, of conuufami, wtniu; t:^ anr^ntnte nmcozie ^^om-
tained only 5 per cent. Thusv 'indcr ^miiar -^s/ruurujittx sa. *o
temperature, alumina is sx amcs more ^oMUiie n a lepacsmr-
magma than in an auurtluteHnagma.

The experiments with the aibite-fna^ma -acre ^oxepcxomUy
interesting, for in addition to cDmndmn. needk» nd siHrnamse
were obtained, and as these aorocthncs ^ntscsxt rtit: ruymndoxf» x
was dear that they had formed fnx. !¥aw, :n aibite '^^ O.
Alt, O3, 6Si O;) the ratio of »da to amnuna u> siica .^ t i H.
The formadon oi sillimanite might tticreaore le mnonaiiiy ex-
pected to occur if there were an gxrg« 09 siica » ^pttd a» aiununa
above that given by this ratio. F'lrrticr ^scperrmems smved rtiat
this is the correct explanation, .^llimanite 'Vjiud ea*iiy le pro-
duced by making a magma :n wmcn ^riiti iitmiina and viiica wcse
in excess of that giv«i by the rano r : ^,

Hare then we have a dear demonssnuion ^i rtie c'»nditioi»
under winch corundum and silimanite may form .n .gneous
magmas. Spinelle and cordiente cnme inder *he ^ame 4rw.
Both require the presenile of magnesuL and cnrdierne ref|mres
also an excess of silica, above that necessary \c% form felspar with
the soda, pota^ and lime present. Twenty-^ive ;pamme» of a
mixture corresponding to pure ^pineile Mg^->, A*tO.^ were
added to a mixture corres^pcmding to iihite. The ^rofiied ma» was
found to be crowded with micmiite* of fpineile. ?\z3ue:.'^ of
corundum and pnsms of silimanite were aiso formed near the
wall of the crudble, but not in tne centre of :he massL

Cordierite was formed in a ma4pna. rn andesitic 'tnaracter in
which the ratio (i^ the feispathic hases m aiumina *o iiiica was
1 : 1*25 : 7 and in which 5 per cent, of magnesia. wa» present.
The cooled mass cons^ed of x^cstaic^nic. 'iryitais of cordierite,
ortahedra of spinelle, prisns <yi iai^ridorire, :ix\d microlites ni
aogite in z ^asy hase^ It bore the dnseat rescmbiance to a
copc&rite-vitrophynte fimn the Oraige Free 5lace described by
Molesigraa^ and to the allied rocks ftrira the south-east of Spa:::
to which I have already referred.

Dc Mbroaewicz suromarises his results as foilows :

In sapetsBtuxated aluminaHBlicace-magmas whose general conir

72 J. J. H. TEALL ON

position is MeO, wAljOs, «SiOj (Me^Kj, Noj, Ca; «>2), the
whole of the excess of alumina (^/— i) separates out: (a) as
corundum if no magnesia or ferrous iron be present, and if
ff be < 6; (b) as sillimanite or sillimanite and corundum if /f be > 6.
When the magmas are rich in magnesia the excess of alumina
separates out (c) as spinelle or spinelle and corundum if » be < 6;
and (d) as cordierite or cordierite and one or more of the other
minerals if n be > 6.

The experiments of Dr. Morose wicz give a very complete and
satisfactory account of the conditions under which corundum
forms in telspathic magmas. But the mineral is found also in
non-felspathic rocks, such as the dunite of North Carolina, where,
according to Dr. Pratt *"\ it has crystallised out of a dunite-
magma.

Now, in his experiments with basic magmas containing magnesia,
Morosewicz found that silicates of magnesia were rare or absent
in those masses which contained corundum. Almost the whole
of the magnesia combined with alumina to form spinelle, and it
was only when there was a deficiency of magnesia that corundum
was produced. Moreover, in magmas with an excess of silica
over that necessary to form felspar, cordierite was produced.
How then can alumina crystallise out of a highly magnesian
silicate-magma ? Why are not spinelle and cordierite formed
instead ?

I cannot answer these questions. Will someone who has the
necessary means at his disposal experiment on the solubility of
bauxite in a peridotic magma ? If Pratt's theory of the origin of
the North Carolina corundum be correct, alumina should be
soluble and should separate out as corundum.

In the preceding sketch of the natural history of corundum,
spinelle, sillimanite, and cordierite, I have by no means exhausted
the subject. I have merely called attention to a number of well-
established facts which throw a considerable amount of light oo
the mode of origin of these interesting minerals. It is clear that
they may be formed by the crystallisation of sedimentary deposits
under the conditions which prevail in the deeper portions of the
earth's crust, and that they may also crystallise out of molten
magmas. They serve therefore as a bond of union between
igneous and sedimentary rocks. The cordierite-bearing contact-
rocks have certainly never been in a state of igneous fusion ; and
yet there has been a sufficient amount of molecular freedom to
admit of groupings of the same type as those occurring in molten
magmas.

To what extent can these minerals be regarded as the
products of normal igneous magmas ? In many cases where they
occur as authigenic constituents, they have undoubtedly
crystallised from a magma which has been modified by the
absorption of foreign material. Indeed, so frequently is this the

CZIHlllHaiXa Jk2!IU ITS \SBUCIAX}!i!>. T^

t acHffiniTff of oimmd aaapmB ospauiie vir runmn^

. izgim*gn& jmi iiilimgnitR :a E chiniu <jpttn cu v^uisstiim.

'sxm ^sBEf bi& duszs can. be au viuubt ri&it :iuch

f :ftm iBcr bisK^ on die ^.(iiisduix af rhe obsiorptiun Qt
ibsri^BBsas :xKits? In days, ^thnies^ oiiii stues chtare
B a lai^ tfinrw if jiiummL aver mar required ru rurm ttdsgwr
wis^ :^ j^iiLJs .imr ixne greseit: Thus in a Casi >£cacHire day
inaK Ffflpgrrrg reccniy jBmlyaed by Dr. Poilanl me mulecuiar
» 43C ±e ^Tra>'r»i^ mil ime :u aiunnmL is c 4. ur : :n :wo ^siucsst
srse Arc5aatu& jooiyaiad by Ptxid ilenttnl ic is c 5':$ imi
1 : 3-5 jeapectpway. Ir aica rocks were xbsorbed by ijranice on
an ^■^i'^wi HI* ica.fr. would aoc sllmmmte Jiid curdience be dir
^Kve fiynnmn rhan ±ey icmoily are^ At drst :siipc one 121
Tiy^n*^ Zai- xasver rhis luesdun imhesitanniciy Js the oriEnnaave ;
bcs cannon b aesxsssiry^ obr nmfa" phipjnie cumiinons micis mav

Thos^ I ba^e noticeil. where biocite-fnebssei have been used
in dde ooGStnnctiaii oc vitnned djrts in Scodand chac ctie !>iuate
is oteo le^caented by a brown giass coacatoin^ b«:auti^al licide
<iGtabedni of spfmeTe. and Vemadskr has sht.'wi^ that the tusnca
of moscoTtte zi^es rse to the tunnarion or silroianitif and
<juiuudiun.

Now it tftac warer in biocite be reckoned is a base alon^
-with pocash :he rano :i {K^ HJ O to AL.Oj :s t i as i:i the
^dsparSy bat in msed biodte alter the water his been dnv\-n otT it
is 1 : 1 'J. and the conditions necessary tor the toruiation ot'
r^nelie exist. In fused muscorite the ntio is i : j. ir-.d is ther^
is no magnesia the conditions necessary tor trie toruianori ot siUi-
manite and comndum exist. Thus the absence ot* the minerals m
<luesdoa from plutonic rocks cannot by itselt be ciken is evidence
that no absorption ot argillaceous sediment his tiken place.
^Nevertheless, I think that when the distribution and ^[uintitattx-e
relations of the micas to the other constituents ire tiken tnto cv>n
^ideration, there is good evidence, quite ifKirt fn^m the tield
Tdations, that granite masses, such as those ot* ComwilU the
-south of Scotland, and the newer granites of the Highlands of
Scotland, have not absorbed or dissolved any appreciable amount
of argillaceous material. When we come to the older granites and
the associated gneisses of the Highlands, which, as Mr. lUrrv>w has
shown, are so mtimately connected with intense and widespread
metamorphism, the case may be different. The extraordinary
abundance of micas in some varieties may very ^K)ssibly repre-
sent in part sedimentary material which has taken this form instead
of giving rise to corundum, spinelle, sillimanite, or cordierite as it
might have done if the water had escaped.

But the full discussion of this question would carry us too far,
and I must conclude by expressing the hope that I have succeeded

74 J- J- H. TEALL ON CORDIERITE AND ITS ASSOCIATES.

in proving that great interest attaches to the study of minerals
from all points of view, and that it is only by combining the
results of geological, mineralogical, and chemical research that
their natural history, in the proper sense of the term, can be made
out.

LITERATURE OF THE SUBJECT.

1. Harrington Brown and Prof. Judd. — **The Rubies of Burma."

Trans. Royal Soc.^ Lond.^ vol. cIxxxviiA, 1896, pp. 151-228.

2. Busz, Prof. — ** On the occurrence of Corundum, produced by Contact-

metamorphism." Geol. Afag.^ 1896, p. 492.

3. DiTTMAR, Dr. Carl. — " Mikroskopische Uniersuchung der aus krystall-

inischen Gesieinen, insbesondre aus Schiefer herriirhenden Auswiirf-
linge, des Laacher See.*' I'erh. d. natur. Ver. Rhein^ etc., Bonn,
1887, s. 477.

4. Holland, T. H. — "A Manual of the Geology of India." Economic

Geology. 2nd edition, 1898. Part I, Corundum.

5. HUSSAK, Or. E. — " Ueber den Cordierit in Vulkanischen Auswurflingen."

Sttz. d. k. Akad, d. Wiss. Wien, B. LXXXVII (1883), s. 332.

6. Koch, Max. — "Die Kersantite des Unierharzes." Jahr. d.preuss. geol.

Landesansty 1886, s. 44.

7. Lacroix, Prof. A. — **Les modifications endomorphes du Gabbro du

Pallet (Loire Inf^rieure)." Compt. Rend., T. CXXVII (1898), p. 1038.

"Sur la formation de Cordierite dans les roches

sedimentaires fondues par lesincendies des houill6resde Commentry."
Compt. Rend., T. CXI 1 1 (1891), p. 1060.
9. LaGORIO. Prof. A. — " Pyrogener Korund, dessen Verbreitung und Her-
kunft." Zeit.f. Kryst., B. XXIV (189$), s. 285.

10. Lasaulx, Prof. A. VON. — '* Ueber das optische Verhalten und die Mikro-

struciur des Korund." Zeit.f. Kryst., B. X (1885), s. 346.

11. Miller, Willet G. — "Economic Geology of Eastern Ontario '

(Corundum and other minerals). Report of the Bureau of Mines,
vol. vii, third part, 1898, p. 207.

12. Molengkaaf, G. a. F. — Cordierit in einem Eruptivgestein aus Siid-

Africa." Neues Jahrb., 1894, B. I, s. 79.

13. MOPOSEWICZ, Josef. — " Experimentelle Untersuchungen ueber die

Bildung der Minerale im Magma." Tscher. Mitth., Bd. XVIII
(1898), pp. 1-90 and 105-240.
14 Osann, Dr. a. — '* Ueber den Cordierit-fiihrenden Andesite vom Hoyazo *'
(Cabo di Gata) Zeit. d. dent. geol. Gesell., B. XL (1888), p. 701.

15. PiRSSON, L. V. — "On the Corundum-bearing Rock from Yogo Gulch,

Montana " Amer. Jour. Sci., 4th Series, vol. iv (1897), p. 421.

16. Pratt, J. H. — "On the origin of the Corundum associated with the

Peridotiies in North Carolina." Amer. Jour. Sci., 4ih Series, vol. vi,
1898, p. 49.

17. Frohaska. — " Ueber den Basalt von KoUnitz im Lavantthale und dessen

glasige Cordierii-fuhrende Einschliisse.'* Sitz. d. Jt. AJtad. d. Wiss.
H'/>». B XCII (1885), s. 20.

18. Salomon, Dr. W.— " Geologische und petrographische Studien am

Monte Aviolo." Zeit. d. deut. geol. Geseli, B. XLII (1S90), s. 450.

19. Vogelsang, Dr. Karl. — " Beitrage zur Kenntniss der Trachyt-und

Basall-gesteine der hohen Eifel." Zeit, d. deut, geol. GeselL,
B. XLII (1890), p. 25.

THE DRAINAGE OF CUESTA&

Bt Pwnsaoa W. If. DAVIS, of Harrani Univcnitj.

YOUNG coastal (^ains present an even slope from the base of a
hiUjbackgnNUid of older land to their simple shore line. Rivers
that are extended across such plains, following a course that is
consequent on the slope of the suiface, dissect ihem trans\-ersely,
opening shallow valleys between strips of low uplands. The latter
may be called "do^U*" (more explicitly, young coastal plain
doabs), or two-river spaces, by a slight extension in the
meaning of the word as used on the great fluviatile plain of
northern India, where it applies to the pointed area of land that
lies between the two forks of a river. As time parses and lateral
drainage is developed on either side of the main consequent
streams, ravines are gnawed in the margins of the doabs, and
they thus come to be fringed with many branching spurs ; they
may then be called frilled doabs. Still later, little trace of the
continuous upland siufaice will remain, so completely have the
lateral valleys been developed ; the interfluviatile strips may then be
called maturely-dissected doabs,* Thus a series of systematically
developed forms may be sketched out and matched with actual
examples at nearly every step.

With greater regional elevation the coastal plain becomes
broader, and older strata are reached when the valleys reveal the
basal members of the stratified series. So long as the strata are
of essentially uniform resistance to the weather, or so long as the
more resistant strata are at the bottom, and the less resistant are
at the top, no significant variation from the doab type appears.
But when weak basal layers are covered by distinctly stronger
layers in the middle or upper part of the series, the transverse
relief of the doabs may give place to a longitudinal relief of quite
another appearance. The weak under layers soon undermine their
thin cover along the inner part of the plain, and waste away close
to baselevel, forming an inner lowland. The resistant layers
still retain a significant relief, with a rapid descent across their
outcropping edge to the inner lowland, and a long gentle slope to
the coastal lowland. The valleys of the extended consequent
rivers are relatively narrow where bordered by the resistant layers
of the upland. Chunnenugga ridge in Alabama is a good example
of a longitudinal upland of this kind ; the inner lowland is known
as the Black Prairie from the colour of its rich soil, and here are

* Objection may be made by obMrv-ers living in the Punjab to the extension in the
meaning of doah here proposed, on the ground that only the original meaning of the term
sbould be employed. But such an ob|ection goes too far. for the original meaning of the
term is simply the confluence of two nvers, and it is only as a secondary meaning that the
space between two confluent nvers is understood. Kt>'moIogically, the term applies also
to the space between two associated rivers that »re not confluent, and when thus used it is
not further from its original meaning than delta is ; for some deltas are not triangular in
outline. It should be understood that a two-syllable sound should be given : d^a^.

May, 1899.]

76 W. M. DAVIS ON

the chief cotton plantations and several of the larger cities of the
state; the outer lowland is called the Coastal Prairie. The
" ridge " itself is a broad upland, much dissected by small valleys,
and nowhere presenting the narrow crest-line which the term
ridge ordinarily suggests. A good view is obtained across the
inner lowland from the spurs on the inner slope of the upland ;
the outer slope is so gentle that its inclination is hardly notice-
able. Such an upland may be called a '* cuesta." Coastal plains
having their upland and lowlands thus arranged in longitudinal
belts may be called " belted coastal plains."

It is not uncommon to find Mesozoic or Palaeozoic strata still
standing in such a relation to an older land-mass as to suggest
that, when first lifted from the ancient seas, they formed the
basal strata of coastal plains, whose subsequent history revealed a
succession of doabs or cuestas, according to their structure.
After the greater or less obliteration of their earlier relief, regional
elevation may have called forth a new series of forms. The
forms seen to-day are members of the n-^^ series in such a
succession. In consequence of the greater chance of induration
in the strata of ancient than of modern costal plains, cuestas
predominate among the reliefs of the former, and doabs among
those of the latter. The Oolite and Chalk cuestas of the
Mesozoic coastal plain of eastern England, and the Niagara and
Devonian or Carboniferous cuestas of the Palaeozoic coastal plain
of the northern United States may be cited as examples having
well-defined longitudinal relief. There may also be an imitation
of the structure of coastal plains, where uplift places masses of
ancient rocks in appropriate relation with gently-inclined strata
of later date. For example, the ancient rocks of the Odenwald
and Schwarzwald imitate the older land, with regard to which the
Triassic and Jurassic strata on the east and south-east stand in
the relation of a coastal plain series ; and a superb cuesta, whose
strongest relief is known as the Schwabische Alb, is determined
by the heavy Jurassic limestones. A beautiful series of cuestas is
found in France, eastward from Paris ; the Vosges here represent
the older land, while five or six resistant strata, alternating with
weaker strata^ from Jurassic to early Tertiary in date, form
ouestas of greater or less strength and continuity. These are well
described in De Lapparent's ** I^^ons de Geographic Physique."
A few words as to the term cuesta. Anyone who will revise
the examples mentioned above will find a distinct repetition of
physical features in them all. The upland is always formed on
the more resistant layers, with a stronger slope on the outcrop
side toward the older land and a gentler slope on the dip side ;
yet no indication of this unity of characteristics is to be found in
the names by which these forms are known. If physical geography
is to advance, the recognition of recurrent features must be indi-
cated by naming them as a class. Finding no name in use for

THE DRAINAGE OF CUESTAS.

the fonns here considered, I have, after waiting several years in
hopes of finding a satisfactory word, advocated the general
adoption of the term cuesta, and for the following reasons :
Cuesta is a Spanish word, meaning hill or slope. The term is
actually employed for forms resembling those here described in
New Mexico, as is stated by Hill in an important article on
" Descriptive Topographic Terms of Spanish America " {Nat.
Gfogr. Mag,, vol. vii, 1896, pp. 291-302) ; or, to be more precise,
cuesta is the name ofthe upland and the long, gentle slope of such
forms. By the same natural extension of the original meaning
that makes mesa apply to the whole of a tabular elevation, instead
of only to its upper surface, cuesta may be made to apply to the
entire body of the unsymmetrical linear elevation that is charac-
teristic of certain denuded coastal plains. There may be objec-
tion to this use of the word, but, until a better name is suggested,
cuesta will serve a useful purpose.

Fig, I. — Diagram of a Cuesta, Developed by the
Mature Denudation of a Coastal Plain.

The morphology of a cuesta is so systematic that definite
names arise very naturally for its several parts. Its upland
descends by a gentle outlooking slope to the outer lowland L,
(Fig. i), and by a stronger infacing slope or in face to the inner
lowland N, beyond which is the stripped belt T, and the older
land O. If the inface is strong and steep it is called an escarp-
ment ; but this term, which applies as well to the rimming cliffs
of a mesa, cannot be advisedly applied to the entire body of a
cuesta, although such is the usage of some English writers.
Escarpment is already so well defined and so useful in its proper
sense, that it should not be made to include the outlooking slope
of a cuesta, which has nothing like an escarpment in its nature.
If the strata of a typical cuesta have a dip of ^s^ or ten degrees,
then a change to a gentler dip causes a greater irregularity in the
outline of the inface, until the cuesta becomes a mesa ; while a
change to a stronger dip produces a sharper and more rectilinear
crest and a greater approach to symmetry in the lateral slopes.
May, 1899.] 6

W. M. DAVIS ON

until the cuesta becomes a ridge as in Fig. 2 ; or, as Hill pats
it, '' a cuesta is, in a manner, a transitional feature between a
mesa and a mountain."

The drainage of a cuesta on a modem or a mediasval coastal
plain gives an interesting illustration of the spontaneous rearrange-
ment of the initial consequent streams by the subsequent growth
of longitudinal streams in the area of the inner lowland. The
diversion of the upper waters of the smaller consequents to become
tributary to the larger ones, and the dwindling of the lower
courses of the beheaded streams have been described in my
"Notes on the Development of Certain English Rivers" (TT^e
Geographical Journal^ vol. v, 1895, PP« 127-146). A very
symmetrical example of changes
of this kind is described in the
course of an article on "TheSeine,
the Meuse, and the
M.^%^\\e\NaLGtogr,
Mag.^ voL
vii, 1896,

Fig. 2.— Diagram of a Cuesta as a transi-
tional Form between a Mesa
AND a Ridge.

pp, 189-
20S, and
Annaies de
Geogr,^ vol. V,
1 896, pp. 25-49).
In more ancient
coastal plains, the longitudinal subsequent streams, following the
lowlands of weaker strata, become more and more important ; and
what with unequal movements of elevation and depression, the dis-
charge of these streams is not always to be found down the dip of
the strata in the direction of the initial consequent master streams,
but it may come to be at one or the other end of the lowland, as
is the case with the Severn* and the St. Lawrence. Yet on all

•^ Various examples might be given to show that the origin here suggested for the
longitudinal streams of the lowlands of belted coastal plains is not always recognised. For
example, Prestwich thought it possible that the Thames once ran north-east from Oxford to
Cambridee along the lowland that is determined by the weak Oxford clays, and that its
passage tnrough the Chiltem hills (Chalk) by the gap at Goring was the result of a later
diversion {Quart. Joum. Geol. Soc., vol. xlvi, 1890, p. 177). Dr. Gregory does not accept
this view, but suggests that the Avon and the Trent, which follow the lowland determined by
the weak Lias or Trias strata inside of the Oolite escarpment, may be consequent upon a
general uplift of central England, with greatest height near Rugby, and radial slopes tnence
outwanis in all directions (Natural Science ^ vol. v, 1894, p. 106). The difficulty in such
explanations is that they do not take sufficient account of the arrangement that the river
systems would acquire during the denudation that preceded the date at which the explana*
tions begin. The original extension of the Mesozoic foimations of central England was once
much greater than it now is. During the great denudation from the original to the existing
extension of these formations, there must have been opportunity for much adjustment of
streams to structures, as described in the Geographical J ourtial, above referred to. It does
not seem admissible to leave all these possibilities out of consideration, and to assume
one or anof hei course for a river, without regard to the previous history of its basin.

THE DRAIIfAGE OF CUESTAS.

cuestas the residual consequent streams are losing drainage area,
and the opposite or obsequent streams are gaining, as the inface
wastes and retreats in the direction of the dip. This brings me
to the most interesting point in the evolution of cuestas ; namely,
the signs of progressive changes now and recently in operation, in
illustration of which I wish to describe certain special features
observed in the strong cuesta of the Swabian Alp of Wurttemberg
in 1894, and on the smaller cuesta of the Cotteswold Hills of
England in 1894 and 1898.

The general features of the first example are shown on the
GeognosHsche Uebersichtskarte (1894) and the Gewasser und
Hohtnkarte (1893), issued by the Konigliche Wiirttembergische
Statistische Landesamt. Topographic details may be found on
the sheets of the Karte des Deutschen Retches (i : 100,000), as
far as issued. A general section through Stuttgart exhibits a
typical succession of forms, as in Fig. 3. The heavy limestones

Fig. 3. — Section of the Swabian Alb, from Heilbronn
TO THE Danube, looking North-east.

of the White Jura form the chief cuesta, whose general name
hereabouts is the Schwabische Alb (sometimes **Alp,") with
various local names, as Rauhe Alp, Heuberg, etc. Two members
of thw limestone, 8 and 10 (Fig 3), and a weaker intermediate
l^ycr, 9, determine a doubling of the upland crest ; the lower
member, an even bedded limestone, forms the chief promontories
and cliffs of the intacing escarpment ; the upper member, of
more irregular structuie, covers the outlooking slope ; it advances
towards the escarpment and fades away on the upland in spurs
and hills, beyond which a flat platform leads forward to the main
cliffs. The stronger member of the Brown Jura, 6, makes a bench
near the base of the infacing slope. The Black Jura, 4, makes a
subordinate cuesta in the neighbourhood of Stuttgart (Scharwald,
Welzheimwald), and the Keuper (Upper Trias, 2), makes another
near Heilbronn (Lowensteinberg, Heuschelberg, Stromberg).
These subordinate cuestas are much dissected by small
valleys.

It is evident from the above section that all the strata there
represented once had a greater extension to the north-west, and
that they will in the future be worn back further to the south-east.
The strong limestones of the White Jura must generally form the
chief divide during these changes. This divide must retreat to the
south-east, because of the arrangement of strong and weak strata.

W, M. DAVIS ON

Hence the consequent streams on the high ground of the out-
looking slope will be more and more shortened or beheaded,
while the obsequents on the lower ground beneath the infacing
escarpment will be lengthened. Thus the
Danube's loss is the Neckar's gain. The cuesta
should to-day exhibit, in different parts of its
length, various signs of these progressive
changes. If ST (Fig. 4), represents an early
stage of a consequent stream with its branches,
and B represents the present position of the
divide on the cuesta crest, then the main
stream will normally be found heading at K
in much diminished volume, while the small
lateral stream J will not yet be affected. The
larger ST was in the beginning, the deeper will
be the notch in which its beheaded remnant
lies; and through these deeper notches the
chief roads and the railroads will be laid, thus
recalling the reason for the location of certain
Fig. 4.— Diagram passes over the inner range of the Himalaya to

° BE-l^^ErCoJr.^ ^^^ P^^^^^^ ^^ ^'^^^^^ ^s explained by Oldham
SEQUENT Streams {Geographical Journal, vol. iii, 1894, p. 169).
AND CuESTAs. A wholc serics of deducible features of this

kind is to be seen near Ebingen, where the
Schmiecha is the beheaded consequent and the Eilach is the
encroaching obsequent. If one ascends the Schmiecha from the
Danube, the stream is manifestly too small for its valley, for
while the valley swings in strong curves, the stream wanders in
small, irregular curves on the valley floor. At Kaiseringen (Fig. 5)
the valley has a well-defined meander to the west, and a narrow-
necked spur enters the meander from the north-east to south-
west. Where the valley walls are concave they are steep and
wooded; where convex, they have a gentle slope, and are
generally cleared and cultivated. Nothing less than the centri-
fugal force of a large
stream seems com-
petent to originate a

valley of so highly , ^^^_ ^

specialised a form. The .jl.-^^'^'^^-^^'* ' -^ -. ^
valley of a small stream i^^^^^^nfBtit^^Z,^ :^'
may, in time, become " "^^

wide, but it can never ^^
acquire the peculiar
curvature and form
appropriate to the valley

of a large stream. The deeply incised meanders of the Wye
illustrate the typical relation of accordant curvature in stream and
valley. No less impressive are the meanders of the north branch

Fig. 5.— Birds-eye Diagram of the
Schmiecha at Kaiseringen, look-
ing North.

THE DRAINAGE OF CUESTAS.

of the Siisquefaanna in the Allegheny plateau of northern
Pomsyhanta. The beautiful serpentines of the valley of the
Seine in the Chalk plateau of Normandy above and below Rouen
again illustrate the normal proportion between product and agent.
The swilling valley of the Moselle below Bemcastel teaches the
same lesson, only to be re-enforced by that of the Neckar
between Heilbronn and Heidelberg. After seeing these repeated
examples of accordance between stream and valley, the dis-
cordance between the Schmiecha and its broad- floored, meander*
ing trough is very striking. It recalls the striking discordance
between the minute irregularities of the Bar, a tributary of the
Meuse in northern France, and the sweeping curves of its
meandering valley, a discordance that is demonstrably the result
of the loss of the former upper waters of the Bar (now called the
Aire) by diversion to the Aisne (De Lapparent, Annaies de
Giogr., vol vi, 1897, p. 79).

Passing further toward the north-west, the disproportion of the
Schmiecha and its valley becomes excessive at Ebingen, where the

Fig. 6. — Sketch of the Valley of the Schmiecha from thk
schlossenfklsen near euingen, looking south-kast.

landscape may be finely observed in bird's-eye view from a tower
on the Schlossenfelsen (S, Fig. 7), on the verge of the upland east
of the town. The high and steep walls of the valley on the
south, cut chiefly in the firm limestone of the uplands, descend to
the flat grassy meadows of the valley floor, where the little stream
wanders about in haphazard fashion, as in Fig. 6. Here, as well
as further down stream, the valley floor has the appearance of
being aggraded, or built up with stream-borne waste, for it seems
to lap upon the base of the side slopes. At Ebingen (E, Fig. 7)
a flat-floored side valley comes in from the north-east, and as more
water comes from the stream in this side valley than from the con-
tinuation of the main valley, the former is regarded as the "head" of
the Schmiecha. Both the side and the main valley here increase
somewhat in width, probably because the upper limestone is
thinning out and the weaker layers next beneath therefore exert a
greater control over the valley forms. The main valley from

W. M. DAVIS ON

Ebingen to the divide, about two miles distant, is almost or
quite dry, and in the absence of a stream the waste from the
walls encroaches upon the floor, giving its cross section a catenary
curve. Little fans of rock-waste are spread forward at the base
of small ravines that descend from the uplands, and between
some of these fans the valley floor is somewhat marshy ; but in
general its surface is occupied by patch-work fields. The valley
walls are continued for several miles further on, and for perhaps a
tenth of that distance vestiges of the Schmiecha floor are seen as
benches at appropriate altitude on the side slopes ; but on passing
the well-defined divide the valley bottom descends rapidly to the
north-west, and the Eilach, fed by several side valleys, soon
l)ecomes a rushing stream of direct course between slopes that
unite in distinct V-form at the stream line.

The contrast in the form of the valleys on either side of the
divide is very striking. On the south-east the highway runs on a
straight line, and with a very gentle ascent, from Ebingen to the
divide ; then it turns to ri^ht and left to lessen the slope on the
descent to Lautlingen (L, Fig. 7). Going on to LaufJTen (F), it
finds no flat valley floor, but has to bench its way along the valley-

Fig. 7.— Section of the Swabian Alb at the Divide between the
Eilach and the Schmiecha, looking North-east.

side that descends to the sharp-cut stream line. LaufTen is not
spread out on a plain, like much of Ebingen, but perches on a
slqpe. Looking back to the divide, it has the appearant e of an
even wall across the valley-head, as in Fig. 8. The valleys of
the side streams are no longer flat-floored, like that of the branch
that enters the Schmiecha valley at Ebingen, but are sharply
incised. One comes from the north-east ai Lautlingen, and the
village of Margarethen (M, Fig. 7) is almost hidden in the trench
that has been cut beneath the former floor. A wet-weather stream
that has very recently been diverted from the Schmiecha to the
Eilach is just beginning to deepen its course. The railway that
found an easy path in the valley of the Schmiecha, with low
bridges of light con*itruction across incoming side-streams, begins
its north-west descent by cutting into the valley-floor a quarter-
mile before reaching the divide; then, descending rapidly, it soon
has to build a high viaduct in crossing a deep-cut stream from the
south-west. The names, Eilach and Lauflen, appear to be derived
from the activity of this obsequent stream.

The valley of the Eilach rapidly widens as the limestone thins
on the upland, and as more and more of the weaker strata of the

THK ML\UIAGS OF CUESTAS. S3

P^ce appear od its slopes. The escvpment is reached a litde
beyond lanflfen^ and then fbOovs the open country of the upper
Neckar, wifh its lov coestas. as shown in Fig. 3. A fine view
of aU these features north-west of the divide may be had from the
Horn, a sharp promontory west of Lau£fen, reached by a path that
ascends along the wooded slope. The upland on the north-east
side of the vaUey is seen in profile, with the village of Burgfelden
(B, Fig. 7) on the edge of its even platform overl6oking the
Eilach valiey. It seemed to me that the story of Jack and the
Beanstalk m^ht wdl have originated in the lower villages amid
such surroosdings.

A few miles north-east of the Schmiecha and the Eilach come
the Laudien and the Starzel, repeating item by item all the
features above described. As before, the Lauchert wanders about
aimlessly on a flat valley floor, at one place flowing a hundred

Fig. S.— ViEni* of the DrviDi betwun thi Eilach and thi

SCHIUICHA, LOOKING SOUTH-EAST. (LaUTU.NGIN IS JUST BILOW

THI EVEN Floor of thi Dividi.)

)*ards directly "up stream,** while the valley follows sweeping
curves, with stronger and gentler slopes on its concave and convex
walls. As before, the disproportion between valley and stream
increases in passing towards its head. At Neufra, the stream is
already very small ; at Burladiiigen, it is nearly lost, and with its
disi^>pearance the steep walls and flat floor of the valley are
replai^ by a blending of wall and floor in catenary curve. The
grassy meadows are at last replaced by cultivated fields, stretching
across the floor firom side to side, and interrupted only when the
surface becomes marshy between faintly convex fans. Then
comes the sudden descent to the head of the Starzel at Hausen,
with the sharp-cut valleys of the lateral streams that have been
diverted from a higher to a lower discharge ; and a little further
on the promontories of the escarpment stand forth overlooking
the lowland. The famous castle of Hohenzollern caps an
outlier a little to the west.

The only novel feature in this second example is the
occurrence of a large branch valley coming in from the north

84 W. M. DAVIS ON

just below Neufra, and heading in the plateau, like J, Fig. 4. t
was not able to follow this valley to its source, but as represented
on the large-scale topographic maps it does not seem to have
been beheaded. Nevertheless, the stream and valley here
exhibit something of the discordance already described, thus
suggesting either a beheading not recognisable on the maps, or
a decrease of stream volume due to climatic change. The latter
alternative will be more fully considered further on.

Whatever the origin of the discordance between branch stream
and branch valley, there can be no doubt as to the chief cause of
the much greater discordance between main stream and main
valley. By ascending the slope alongside of the watershed in the
valley floor, the contrasted action of the two headwaters is pre-
sented in the clearest manner. So impressed may one become
with the reality of the southward migration of the divide and of
the northward diversion of lateral tributaries, one after the other,
that it is difficult to restrain the imagination from figuring an
active advance of the process, and to maintain a conception of
the extreme deliberation with which the whole series of changes
advances. One comes unconsciously to feel that, if he should
return to the same spot a few years later, a visible progress would
have been made in the wasting of the steeper north-western slope,
and the divide would be found to occupy a position appreciably
further to the southeast. Yet, on considering the extreme slow-
ness of the process, it is manifest that centuries must pass before
the Wasserscheidekreuz by the roadside need be moved. The
extreme disproportion between historical and terrestrial time is
seldom more convincingly emphasized. Nevertheless, it is a
pleasing experience to allow the mind to forget the years and
centuries of human history, to let it drift into sympathy with the
march of events that has developed the existing form of the Alb,
and thus to realise that the march has not yet halted. When this
sympathetic mental attitude is gained, as it is so easily from such
a point of view as is presented on the slopes above the divide, one
sees how little appreciation of physical geography has been
reached by those who contend that the analysis of a landscape
detracts from the enjoyment of its beauty. The truth is that the
finest beauties of the scene, the harmonious relations of its parts,
are not perceived until the analysis is made. So long as analysis
is distasteful and laborious, it must interfere as much with one's
enjoyment as the necessity of frequent resort to a dictionary
interferes with the enjoyment of classic authors ; but when the
analysis of a landscape comes to be like reading a foreign language
at sight, its exercise is not a tiresome effort, but a stimulating
pleasure, and it then adds as much to the meaning and interest of
scenery as the recognition of the true relation of construction and
ornament adds to the appreciation of a well-proportioned Gothic
cathedral in the mind of one who is versed in the history of art

THE DKATKAng. OT CrhSTAS f^

sjsd architectiire. Many a txareDer iae cnsaec tiit Sicanair Air.
bj one or another of its befatcaded Tali£> t^«m ^ nu: sioztfs cr tbt
vadlej side may have attiacted the xxavdicr ^ vm^nnnr m isssoxi of
tlieir graceful descent to the meado«F-iis£ Soar hm ns aiicvnnsn:
€>f the passing view must have ^Uec a£ tar shon of is iuL 'rT»»>ggTTf»- ^^

^rouldttiatof an nntanght Riphtaw»r nr\ Innirrry^ y ynaTt^ynn-^ fT*—c"r

^vhile knowing nothing of the aliegarT or cc is saggssn^ rtManm.

There are several other eaaxg>les of Tii"fwg>rMT sttsbus innnsr
riortb-east, but as my acquaintance wi± tnem s a: prtaexc
S^^^ chiefly trom the smdy of maps, ther Twatc. no: :e iurtzisr
described here. Brief mentiaD may. tiovwevsi. ne: TnarH- a: ^le
zxiaintenance of headwaten far a number x mit*: jnsiiif nonxi-
'wrest) of the escarpment by ^le TTLcncr an£ rre ArmmL
^.pparently because these streams lie abnic micwzj asrvess: die
^eckar and the Main, where the ogcnnnr mg-Tnrrni hzvs nx
yet reached them.

There is one element in the prpbtfrr fha: mz^ s££il u Su2d£
Against the explanation here Qfiered Tie TbLrrs af ziMt lewaogc
^Schfnierha and Landieit still mais ofar nzccss r£ znt ijna
Siv'cn them when their streams were mun ia^^-r : ±i-t b^vt not
siooe then been mnch changed by wearziennc Ani 3^ dbe
ixtxxss of beheading, by which tbese sr-asnf hsTt besc r^±a:ad
from an appropriate to an TnajigjrDprg.Tg- vzirir't^. iiraTfs x >

siderable southward migianon of the cirj5& n r-iir^e: jtcoe :/ ±ie
^flfecdvc action <rf the weadier cc tht nam-»*scer:: i!-ce. I:
tjierefore seems like blowing hoc ar>c ccmz z: ire s«ZDe brearii 10
accept only a small diangc ic ooe pli-re i=»i 2. zz-'Jr. irearer
cdiange in another. This seeming ozfCL'nci'ZZXic. ^ .e&?«ed br
^uro considerations. In the first pliarse, ±e w:'fer.:r::g oc :he
beheaded consequent vaDeys is reiar{5ed by :be res:^car.ce zk 'Jr.^
strong limestones in which they are c:::. whf.e ±e scxiZT.wxrd
KuigratloQ of the divide must have been aooderared by the npid
^^wasting of the weak strata that rww occupy the fio:' Ji the irncr
lowland. Even if the strong White Jura lisr-esrcrjes over-ay :7^
^wveaker layers, the latter would rapidly undermine :he rrnier as
3000 as deep valleys were cut through both. But, in :he -ecKj^nd
](>lace, it is not necessary to assume that a great destmcrion o: the
stronger upper layers was accomplished while the beheading of

Fig. 9.— Diagram of a Clesta in two ogles of den:l'ation.

the streams was in progress. Let it be postulated that MM, Fig. 9,
^Was the eflfective baselevel of the region when it ^as first elevated
so as to be denuded into lowlands and cuestas. During the

W, If. PAVIS ON

mature stage of this cycle of denudation the crest of the ^\litte
Jura cuesta may have had some such position as S ; but in the
old age of the same cycle the cuesta-making strata would be
reduced to faint relief at V, while some of the consequent streams
might still retain their headwaters in the neighbourhood of D if
the attacking obsequent streams did not have at that time suffi-
cient advantage to push the divide further south-east The
Schmiecha and the Lauchert might then have had headwaters on
the weaker strata from D nearly to V ; they would thus have
resembled the existing condition of the Wornitz and Altmuhl, as
stated above. Now, in consequence of a new uplift, by which
the baselevel takes the position NN, let each revived consequent
stream cut a narrow valley, DET, before it is significantly
beheaded; and a graded slope then being reached, so that further
valley deepening almost ceases, let the obsequents push the
divide from D to X, thus reducing the consequents to about their
present small volume. It is possible that still another uplift
changes the baselevel from NN to QQ, for the Neckar to<lay
occupies a narrow valley for much of its length, incised beneath
a broadly-denuded surface ; thus the obsequent profiles would be
changed from XW to EF, which imitates the present condition
satisfactorily. Under these suppositions only a small part of the
strong White Jura limestone was consumed while the consequents
were shortened from a length of DT to ET, and even the part
thus consumed was worn back chiefly by the undermining of the
weaker layers of the lower infacing slope. Guided by such sup-
positions as these, it is not unreasonable to suppose that the con-
sequent valleys in the hard limestone still retain much of the
form given to them before their streams were greatly diminished
by beheading.

Whether the postulates here introduced as to successive base-
levels, M, N, and Q, are correct, can only be determined by the
study of a large area ; but as far as I have read there is nothing
to contradict them. Whether the postulates aid or encumber the
explanation is, perhaps, a matter of taste and temperament,
varying with the degree of confidence felt in the various general
onsiderations previously introduced.*

• Reference may here be made to the importance of the consideration of baseleveU and
cycles of denudation in explaining certain problems of American geomorpholog^. Lesley

expressed surpnse ai the

small amount of erosion

accomplished on the low
anticline, A (Fig. ioa), to
the Allegheny plateau,
while an immense amount
of erosion had been accom
plished on the huge anti-
cline, B, of the neighbour-
ing Allegheny mountains,
both rock-arches having
been rx posed to denudatioD
for the same periods of
time {Second GeoL Sun*. Penn.y vol. x.). But when it is recognised that the region con-
cerned stood for a long lime in a lower position, with the baselevel MM, and that only during

Fig. ioa.— Section of the Allegheny Plateau
.AND Ridges in Central Pennsylvania.

THE [>MAIirAi>if oF ^i:^^Txi

TarmnK nov to ifae cacao, oiown js :iie Zotsssmnd. rfulg.
fonned ao tfaeresistaiit Ooiinc soaoz 3f :hs LTesasoic :aaMBi siaoL
of England, let me one rcttr to 21L irrjr'je- jV .It. 'isthaamr Vhine:,
'*On die ori^ of the Sgh-Lere Ifavei «rm 7rs9Bc i^bris
adjoining die Vailej ai die Cpper Thames ' Prsic J^ac .-jycar,,
VOL xv, 1897, pp 157-174^ Ir s :nere ioowii mar mmwianr
giavel deposits, derived fiooDL nxrxs a -.:ie ^:a2ier a .se ^.esexm.
•jccupy the vailevs oi ±e jpper Tignrr.es :)r ne Tfaames a :ae
Cocteswokis. These ^aveis ind -n^r soonie lase .on^ leen
known, and rfaetr digrthnriQa oaa neretcrore oeea accnimiBdrorTvr
OMrioe and bf giacai acDoa : int Mr. jsnome Vime :txmas ihar
iheir best expianadoa is found ix zr/nnecHiin «ich :tie reafran^-
ment of iiveu» appmpriate na lettea xascai plains. Thus 311
independent line of observanon vx^mims :ne leiieaoed rj»uiitxnfi
of the Thanes system^ sad sinjgetfi nat ^zavets maL ztut ^S^aear
faun flbonid be looiced for ji :::e "filers :^' te -<etiea<upn
hfanrhf^ of die Dannhr I ^ery rnucn -c^gr Jiac ::ie ^^sisBesce
of these Cottesvoki ^apeb T«as not ^novn :o neat Jie-^.ae if
pKeparing my ^^kxes on Jie DeveSaqmeat if tertam

Rhrexs.'^in 1894, bat perhaps the racr oi Tinnnq durnu^an acaye taor
aczQBB Fnmoe mav <?Tcnse die iversignt if ic moortantamtcer: '
Mr. Osborne White states chat ^ta :he iiveraon rj-te: yr^nak
headwaters of die Thames system :o iie Screrr. ' -r^ uinoiy if
dSiris arom rocks if earlier n^ :han :he T-as. ^mu:n .:u!t -»ail
hitherto himished. came :o in ^ntt .^nit he --iiiume '>/ waxer
in chese bianch. jtrpams mtL 'nerefhr& jijio n 'he iiain -v 'mnJt
stream, being greatly reduced. :ae Trtirti if ::ie i^-ann*^!; ru?^ -^eae
chcreaJXer abie to ooixe ^«a& lorresoniuiixiglr ^rmnisOii^' i^,
p- 171;. This normal conseqoeflce of :^Je^ iereinpmenr :>i' * •eil^sii-
justed cxzesb dniTTiage ^ios ruit rsxaminect n :.Sr*^:'or ar.:c / :ixne
but during Qrroher, iSoii, I nade ^erersi -:::c:;r»ioni5 iU^n^ -^^
salleys of die «IjerweiL ZvenUide V ru^inan. in/i ^^n. »Tth
most mtexesting ngsniis .U Jie ^aine :n;e. r^e e7i<:«;nre if a.

-i«> :nac"«rt

: .IT Pine Moan.

? < Pu|. :n«i 3aft fUgow; -n

miart .i^*
. ^7. . .-lot J .t riP onmiidieo
Jt«r !i« lacr r tut

jfi?r>j«i tie !.in#npr-lrU. «t3ire a*? -xr^i—airn ■» .ie .-.r:qir.uiiaai ■uitrs' -ji ae
1.MI t lira • :-.uryr -ar tic evrr^

88 W. M. DAVIS ON

climatic change, already suggested on the Swabian Alb, here
enters with greater strength, and thus adds a new complication to
the problem. The one- inch maps of the Ordnance Survey (New
Series), or, still better, the sheets of the coloured one- inch map,
as far as published, exhibit most of the features recognised in
the field. Bartholomew's reduction of the Ordnance Survey
sheets suffice to indicate localities, but are on too small a scale
to illustrate details of form.

The Cherwell seems to retain a greater share of its onginal
length than any other of the Thames branches. It is in this
respect, as well as in its relation to the encroaching streams of the
inner lowland (Avon and Trent), a worthy fellow of the Wornitz
and the Altmiihl. Between Banbury and Oxford there are
many indications of diminished volume in the striking discordance
between the minute irregularities of the stream and the swinging
curvatures of its valley. The latter feature is not continuously
displayed, but it is very striking at several points, notably between
North Aston and Somerton, at Upper Heyford, and at Enslow.
At the first and third of these localities, the stronger slope of the
valley side is on the west, and presents a well-defined curve,
concave to the east. At the second locality the stronger slope is
on the east, with a curve concave to the west. These systematic
forms, so characteristic of vigorous, able-bodied rivers, do not
seem to be in any way producible by a little staggering stream
like the Cherwell, which wanders about, as if bewildered, on the
flat valley floor. The diversion of some of its waters to a canal
should be noted, but even if this loss were made good the
Cherwell would still be a small stream. Its headwater divide, at
a height of about 400 feet, between Fenny Compton and Worm-
leighton, deserves closer examination than I was able to give it.

The headwaters of the Evenlode at Moreton-in-the-Marsh
(417 ft.) lie on the broad floor of a wide valley. The gain in
width here as compared to its lower course (as about Stones-
field) is due to its excavation in relatively weak Liassic strata, and
hence no local signs of a meandering valley are to be expected at
this point. The beds of quartzite and other midland gravels at
Moreton are well known (see O. White, /.^., pp. 160-162 In
line with the present upper Evenlode, and a few miles farther
north, there is a small stream known as Knee Brook. It first flows
south from Hidcote Hill, near Chipping Campden, then east to
join the obsequent Stour atTidmington. The south flowing part
of Knee Brook therefore probably represents a former head of the
Evenlode. Midland gravels are found on the hills that divide its
source from north-flowing obsequent streams. Unlike the
present Evenlode, Knee Brook occupies a relatively narrow and
deep-set valley, over a hundred feet lower than the Moreton plain,
and the valley sides descend close to the stream, leaving little
space for a flood plain. Perhaps the name of this brook is

XSK DftAIXAQS or CUISTAS.

cksiied front its nght-ao^ turn firom south to east at the cloow
of capcnre: certaiuly the analogy of ^^ elbow** and "ki\e<?** fe
verj soggiescrve^ Whether the surname of Moreton had its origin
m the macshj cooditton of the valley fioor at the head of a
beheaiied riien or whether tt is a corruption of March, might he
deteriBmed hf tbe kxal antiquariart

Farther down the Erenlciie, where its valley is eroded in the
stronger layers of the Oolite, it is comparatively narrow and
stcejMKfed. Between Stonesfield and Long Hanborougk it is
as perfect an eiainp2e of a meandering \*alley as #ne can wish to
see. A beautiful soccession of interlocking plateau spur^ six
from the north and as many torn the south, enter curves of \try
uniform dimensions^ Each spur slopes gradually to its end>
vhile the concave curve on the other side of the valley is steep»
afanost abrupt. Furthermore, the up-stream side of many of the
spurs is somewhat cut away> and the steep slope of the concave
curves is there prolonged neariy to the end of the spur : one
$par north of Long Hanborough is reduced to a cusp, thus showing
that a beginning had been made in the destruction of the spurt
by the river that eroded the valley. A digression may be made
in foller explanation of this significant feature.

If a mature river, meandering freely on a broad valley floor
in a region of moderate relief, is revived by the elevation of the
region, it (mxreeds to carve a meandering viUley, Its meande^
belt (defined by a pair of sub-parallel lines, tangent to the
meander curves on either side) is broadened as the valley is
incised : hence the spurs descend with a gradual slope towards
the abrupt slope of the concave walls, as in Fig, 11, The
Moselle, below Bemcastel in western Germany,
and the north branch of the Susquehanna, for
some distance below Towanda in northern
Pennsylvania, exhibit these features with great
distinctness. After a graded descent of the
valley floor has been developed, deepening
almost ceases, but widening continues. The
up-stream side of the spurs is gradually
worn away, apparently because the whole
system of river curves moves bodily down
stream. The spurs are at first sharpened
(Fig. 12), then reduced to cusps (Kig. 13),
and at last disappear entirely (Fig. 14),
leaving a flood-plained valley floor on
meanders rather freely, with only occasional constraint from the
valley walls as it swings against them here or there. Various
stages in this systematic sequence of forms may be seen in th«
valleys of the Dordogne and the Lot, as these rivers flow west-
ward from the central plateau of France across the belt of
overlapping Mesozoic formations : a less advanced stage being

FiC. U.— DUliKAM

OK A NaKKOW

MKANDKKINti

Vai.kky, wirn
Symmkikuai,

SlTKS.

which the river

W. M. DAVIS ON

found where the rocks are resistant, and a more advanced stage
where they are weaker. The important point in the present
connection is that the systematic trimming of the ap-stream side
of the Evenlode spurs gives new confirmation to the conclusion
already reached regarding the origin of the meandering valley.
It must have been eroded by a river that was large enough to
swing in regular meanders accordant with the curving valley floor.

Fig. 12.— Diagram
OF A Broadened

Meandering
Valley, with Un-

SYMMETRICAL SPURS.

Fig. X3.—D1AGRAM

OF A Broadened
Valley, with Cusp
Remnants of Spurs.

Fig. 14.— Diagram

OF A Broadened

Valley, with

Smoothed Sides.

Yet the Evenlode itself turns about aimlessly on the valley-
floor. Instead of pressing closely against the steeper slopes, as
the original river must have done while under-cutting them, it
shows no such definite intention, but wanders here and there
from side to side, and is about as likely to nip the gentle slope of
a spur as any other pare of the valley walls. A rapid glance at
these features may be had from the line of the Great Western
Railway, which, in the stretch above described, adopts a com-
paratively direct course, making cuts through the spurs and
embankments across the valley-floor. The steeper slope of the
upstream side of the spurs is easily recognised from the un-
sym metrical form of the cuttings. Even the one-inch maps
indicate this detail of form with much fidelity.

The head of the Windrush was not within reach during the

Fig. 15.— Sketch of the Vallky of the Windrush looking West
past Crawley.

time at my disposal in the field, but between Burford and Witney
its valley meanders with appropriate steep and gentle slopes,
repeating the features just described for the Evenlode. One of
the best curves is at the village of Crawley, where a fine sweep to
the north is entered by a descending spur from the south, as in

THE DRAINAGE OF CUESTAS.

Fig. 15 ; the steeper trimming of the up-stream side of the spur is
feij (lisdnct. Other examples occur just below Osthall. The
cnrriiig floodplain, 00 which the stream idly loiters from side to
side, is very probably somewhat aggraded, for, after loss of volume,
the gradient of the valley-floor must have been insufficient for the
needs of the diminished stream, and the waste washed in by side
streams must have been soon deposited. In this case it would
be natural that exotic pebbles should be found in wells beneath
the alluvial floor. The change in the form of the valley sides,
since the beheading of the rivers, has not been great, although
the slopes are occasionally somewhat ravined.

The Coin is in some re-
spects the most interesting of
the Thames branches, in the
possession of a number of well-
defined features suggestive of
beheading. When visiting its /i
npper course, I profited greatly . 1 I ^^^
tmn the company of Mr. S. S. v. .frr "'-
Buckman, of Charlton Kings,
who was already familiar with
many of the best localities for
observation. In the neigh-
bourhood of Withington, the
form of the Coin valley sug-
gests a progressive diminution
in the size of the river that has
followed it. There are, first,
large-scale meanders, indicated
by the general form of the
curving valley ; second, much
smaller meanders, indicated by
concave nips or re-entrants at
various points on the side slopes
of the larger meanders ; and, third, the minute contortions of the
existing stream. Fig. 16 is a rough diagram, undoubtedly
inaccurate in many details, but serving to represent the relation
believed to exist among the several phases of the history here
inferred. The spurs, lettered A to E, project into corre-
sponding amphitheatre-like concavities, whose floor is above the
present valley floor: thus the path of the original river at the
time of its greatest volume is indicated. Successive concavities,
numbered i to 12, are taken to represent indentations in the
sides of the large meanders, caused by the river of medium
volume ; No. 5 is the most distinct of thete. The existing
stream of small volume flows irregularly on the valley floor.
A careful survey of this locality with the object of making a
detailed contour-line map is greatly to be desired. The top of

Fig. 16.— Diagram of the Vallev
ok the coln about vvlthington.

92 W. M. DAVIS ON

the spur south- east of the village may be recommended as a
good point for a general view. The re-entrant curve marked 5
will surely take the observer's attention from the arrangement of
the small fields or " allotments " upon its slope.

If the above interpretation of the valley form is correct, it
might be inferred that the Coin was once formed by two good-
sized forks, which united somewhere above Withington ; and that
the diversion of the western fork from the Thames to the Severn
system caused the change from the large to the medium sized
meanders, while the subsequent diversion of the northern fork
caused the change from the medium to the small existing
meanders. This inference is well supported by the branching of
the valley at Andoversford, a few miles north of Withington ; one
broad branch coming from the west, the other from the north.

Passing beyond the heads of these broad-floored valleys, one
descends rapidly — in very good imitation of the examples on the
Swabian Alb — by the sharp-cut obsequent valleys of the Chelt
and the Isbourne to the inner lowland of the Severn-Avon
valley. A railway follows the western branch and aids the
encroachment of the Chelt by cutting and tunnelling through the
divide, thus already diverting surface waters to the Severn system
that would have otherwise remained faithful to the Thames for
centuries to come. The broad meadow at the head of the
northern branch falls off abruptly into the wedge-like valley of
the Isbourne. The meadow is continued in benches a little north
of the divide on either side of the valley, but the benches are
actively encroached upon by slips in the weak Lias clays that
underlie them. Just south of the divide, a side valley comes in
from the north-west, flat-floored, as if aggraded ; while to the
north of the divide, a side valley comes in from the east, narrow
and steep sided even in the weak Lias.

According to the map in Mr. White's paper, some Triassic
gravel has been found in the Coin valley, but it must be much
rarer than in the valleys of the Windrush and Evenlode. There,
the red quartzite is a conspicuous element in the soil of many
valley-side fields, and in the construction of many roads ; but
two days of wandering in the Coin valley failed to discover a
single quartzite pebble. In explanation of their absence, Mr.
Buckman suggested that the upper branches of the Coin had not
cut down through the Lias to the Trias at the time of their
diversion to the Severn.

If the spontaneous rearrangements of drainage area here
described were the only causes of change of volume in the
streams, the branches of the Severn system ought to be as robust
as those of the Thames system are feeble. To test this con-
sequence of the theory, I visited the Stour in the neighbourhood
of Shipston-on- Stour and Halford, and to my surprise found that
stream also a misfit in a meandering valley, although not to so

THE i»R.\INAiTF - T^T". -. ;

Striking a det^ree as in the examnies jrHAr- :eit- r:" er:. cx:r.Tninc
to the iTiap, the Avon is .nzain i r.iisnr ^ • -i.*:-. * . .rt .- irtn

ot this disiricL A similar ronirji:ci::;--r. f • -.e ■ r-r.iizzrL . . Mtua,
m the dLscordancc between rream .nii .-i..f:-. . • .r; 'ise ■ : -*
Meuse titftfre the point where :* .is. . :si : ..• r:: *-r : U.-^i-^Lrz, ^r^n . .
the case r>f the Aisne :i/*t>7'f iTie ronu v-ner:? is ^'i:r.rt: • ^^ . .rif^
It is therefore evident iliat . ome Tier -lUSk- jr. • -s^ :.** r.a" »
<li vides must i >e concern ed .i lese •;. ! : n -. i is r -'.at « , r v; . . . -jr. *?3 :
decrease of uream voiume eems i »i ir^ar.-.--/: r, >.s*r
changes due to diversion .f nr«::Lines rr.m. r.et .;v-r . .;j,rr.
to .mother. It has occurrcci it le 'n.ii : \tz ■ .^ er.v^-ie :iav
l>e due :o increased ':\'ancraiirjn ...ow^rj \i- .-:rjr:;-:..-. ,r
incient forests and i he t ; u Ui v n tir in .« ■ r-^ trr.rx: : i .r,. . - . • ^ r.-.
the chief reason tor -iecreafur .^ i r- iur^ -. r»r.-^ ..: ....^.
change of external and oosriire ' ncin ..-»ii -tu -ncr-ear : \&
problem I <::annot now -iiscuss i:jrtr,«-r.

In spite of tdis climanc nomniirr.iir,^. - .amu.- : «r.i, .:.\r^^ : v
anyone who will examine :ie : vrt:i::t-i iru-^vf^ 'letfTrr^-rr: .at .-.n-
siderahie changes if drainage irens avr^ .eer. auxer: •. le
interaction of the streams Yenisei v*:^ .r.r. ^i './rrjt • -..*.-.:•;-: r/r
01 the kind •>utiined :n ne :n«!^rft!::ra; v.:i-rr./-r.: : -./ r^tiin?
)! this essay. In view .f ^le :c<'.': -. •"*:
former greater - extension - t ' *. -^ . . . pn

-ind north-west, .t .:eems .c-:! fit : . - -.M-r: - .f,
oria^nai -.tream. .isiir. ireccrv .,ia or:- -r.^:
:f) piace : t : n -.he -ratecf . r: x ;::.-«:::: -r.: : r/-.
ment is :he result >•! ^.ennxar.i .r -Arr. .:,n:'
:hus .naking t \r* .cccrn^r.i .ii-mr,irr i .j
ippropriate :o ■'oasui sains- f . i r.n=i»it:r3:.;rr

Whiie :he ::xntanauon ^f v^i :>s:::r.'^': -.1;
from several :onvenruiG :ne$ i -vvi.-r:r.-.
'iedncihle :rom .tie rt^ui ^amnie?: err- »-
of even greater : mportar.rc. T : . «^ ys? i • r: .ai .r
found n the drainaae f 'jesta^; runr
leveiopraent. ana siaTiXsn i ^^f-ti • c:::::f-'r: :.
forms. Anyone wno '^»ecr,mes .i":-^\i^ai:ii :
:Kner3i scneaie .y .-Men r.-.-. :a&r r .r--.
ind :heTe:n i :e:v nsimmer.: : ^r--r,r-r..
naturaiiy turn :o r.i*ic or r-i- .r^r^^acr. : r ",.'
in a :uesta as :r^ inrrair.ert rTx\-".\t:T ..i-;
areazns. HEe ▼ill -« .:% ..Tu- .-. c*:.' ...;
us atepa at >nce :o "jointi »nt^re r.e -.r.ij ii.-rr.car.: -^ :;:;-. en t.-.
ir -"omi are ^peered, irji : r.ev .re •-,---.. .«': ^:1 .uir;:.. jr.a
'anciiely lescnbe r*eai is .lerr.r^er^ : t Tf-:! <^.^-ff^. :ass.
Thus osf erf^ ^vstemacc :ecjrar.r.v ?::! .nc-iilv ^.to :.c
:ijace >f rsnrunrai ^eoarar-nv. ;r..i r.:-; icc .r r.c ar:r. viil
:!ame :o lave .lesv ueanm^ .0 ix r.riai;:iar.t3.

.:;:. ■

v.-.'.".

r lit

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nrri

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rnia.

f r.l.r

.a:i: .

*v!.:m«;

■:n:w.:.:

:■.

i. i.:4-

-,n:.rma:,rin

:/: irr-frrsi

"-v»n

Xr:r,rf;

rir:\ .

. .le

-■s::..f.-

''. ■ r^riZf^rtlv

W.t-rr.

r.l.r.

r/rr '.r

r.iL< :

er^jri

:,nirc;

r* '.r*'

r :r.frc5

r r.e

:,.rfir.r*.'

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T.nner

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;r.rju;e.

.V .;:

■•rrin:^

ANNUAL GENERAL MEETING.

Ffhruary 3Rn, 1899.
J. J. H. Tkai.l, M.A , F.R.S., President, in the Chair.

Messrs. R. Holland and A. C. Young were appointed
Scrutineers of the ballot.

The following report of the Council for the year 1898 was
then read :

'"PHE numerical strength of the Association on the 31st of
■I I)3cemi)er, 1898, was as follows : —
Honorary Members . .16

Ordinary Members —
a. Life Members (Compounded) . . . .15^
A Old Country Members (5-;. Annual Subscription.) 7
c. Other Members (10s. Annual Sub cription) . . 366

Total .545

During the year twenty-three new membcis were elected.
The (Council regruts that the Association has lost two members
by death : Sir Robert Rawlinson and William Walker.

The income of the Association for 1898 from all sources was
;^239 i8s 9d., and the expenditure was ^249 8s. id. There was
also a sum of ;;{,'2i 16s. 2d. due to the printers, against which
may beset ofl"^,'ii i6s. 6d., the amount due for 1898, from the
advertisement contractor. It will be seen that for the first time
for several years the expenditure for the year has exceeded* the
income. This is due partly to the increased outlay on the
library, foreshadowed in the report for 1897, and still more to the
large amount recjuirod for printing the Prockicdinc.s. 'I'he
money, however, has been well spent, for it is a long time since
there has appeared in the PROCKKniNr.s of thk Associatk^n a
paper of such great interest and value as Professor Lapworth's
Sketch of the (Jeology of the Birmingham District. The slight
falling off noticeable in the receipts is due to the fact that fewer
new members were elected than in the previous year.

Five numbers of the I'roceki)IN(;s, consisting of 254 pages of
text, 5 plates and t,2> other illustrations, were issued during the
year 1898. Thanks are due to the Authors for their contributions,
and especially to Professors Lapworth and Watts for their "Sketch
of the (ieology of the Birmingham District," published in the
August number. Your thanks are also due to Professor Watts
for Plate XIH., published in the November number.
May, 1899.]

^ a

r, -

r I

- ± \zy-i-. 1

^^-r.^^ZLr.rr.

ANNUAL GENERAL MEETING.

FKr.RUARY ^RD, 1 899.

J. J. H. Tkali^ M.A , F.R.S., President, in the Chair.

Messrs R. Holland and A. C. Young were appoint
Scrutineers of the ballot.

The following report of the Council for the year 1898 *
then read :

'"PHE numerical strength of the Association on the 3isf
■I I)2cemher, 1898, was as follows : —
Honorary Members .
Ordinary Members —

a. Life Members (Compounded) ....
/'. Old C!ountry Members {$>. Annual Subscription.)
c. Other Members (10s. Annual Subcription) .

Total

During the year twenty-three new meinbcis were
The Council regrets that the Association has lost two 1
by death : Sir Robert Rawlinson and William Walker.

'I'he income of the Association for 1S98 from all foi
^239 1 8s 9d., and the expenditure was ^249 8s. id. *7
also a sum of ;^,'2i 16s. 2d. due to the prmters, agai
may beset ofl"^,'ii 16s. 6d., the amount due for 1898
advertisement contractor. It will be seen that for thi
for several years the expenditure for the year has ex
income. This is due partly to the increased outl
library, foreshadowed in the report for 1897, and still
large amount rcqmred for printing the Proceed
money, however, has been well spent, for it is a Ion
there has appeared in the Pkcm i:r:niNC.s ok the A
paper of such great interest and value as Frofesso
Sketch (if the (leology of the Birmingham District
falling off noticeable in the receipts is due to the f
new members were elected than in the previous yea

I'ive numbers of the rRO(T.Ki)iNf:s, consisting c
text, 5 plates and 33 other illustrations, were issi
year 189S. Thanks are due to the Authors for the"
and especially to Trofessc^rs Lapworth and Watts f
of the (Jeolo^y of the Birmingham District," p
August number. Your thanks are also due to
for Plate XIII., published in the November num
May, i8()9.]

ANNUAL GENERAL MEETING.

The follomng is a list of excursions made during the past
year. Detailed reports will be found in parts 8 and lo of the
Proceedings, vol. xv :

DATE.

April 7 to 12

(Easter)

April 23
May 7

(Whole Day)
May 14

May 21

May 28 to June i
(Whitsuntide)

June II
June 18

June 2$

(Whole Day)
July 2

July 9

July 16

(Whole Day)

July 23

July 28 to Aug. 3
(Long Excursion)

September 10

PLACE.
Brid))ort and Wey mouth.

Reading.

Hillmorton and Rugby.

Ayot Green and HaiBeld.

Penn and Coleshill.
Aldeburgh, Westleton, and
Dunwicli.

Gudalming.
Crowborough.

Suilbury.

KingswootI and Walton-on-
the-hill.

Upper Warlingham

Worm's Heath.
Sheppey.

and

Cycling Kxcursion to Purley,

Coulsdon, and Merstham.
Birmingham District.

Gravesend.

DIRECTOkS.

Rev. Prof. J. F. Blake.

M.A., F.G.S., W. II.

lludlesion, M. A.,

F.R.S.,S. S. Bucknian,
p /^ c

J. II. Bhike, F.G.S.
Beeby Thompson, F G.S.,

F.G.S.
J. Hopkinson, F.L.S.,

F.G.S., A. H. Salter

B.Sc, F.G.S.
W.P.D.Siebbing.F.G.S.
W. WhiUiker, F.R.S.

Pres. G. S., F. W.

Harmer, F.G.S., E. P.

Ridley, F.G.S.
T. Leighton, F.G.S.
G. Abbott, M.R.C.S.,R.S.

Herries, M.A., Sec. G.S.
J. W. Gregory, D.Sc,

K (^ S
W. Whitaker, F. R. S.,

Pres. G. S., W. P. D.

Stebbing, F.G.S.
W. Whitikcr, F. R.S.,

Pres. G.S.
W. Whiuker, F.R.S.,

Pres. G.S., T. V.

Holmes, F G.S., W. 11.

Shrubsole, F.G.S.
Rev. Prof. J. F. Blake,

M.A., F.G.S.
Prof. C. Lapworth, LL.D.,

F.R.S., W. Jerome

Harrison, F.G.S.. W.

Wick ham Kinjij,

F.G.S., T. Stacey Wil-
son, M.D , M.R.C.P.,

Prof. W. W. Watts,

M.A., Sec. G.S.
G. H. Dibley, F.G S.

The interest of the members in the excursions during the past
year has been fully maintained.

Your thanks are due to the Directors of the excursions and
also to the following ladies and gentlemen for assistance and
hospitality :

The Mayor of Bridport, at Bridport ; Mr. Aubrey Strahan
F.G.S., for illustrations for the April Circular; Mr. Llewellyn
Treacher at Reading: Mr. Young, of Rugby ; Mr. W. H. Williams,

ANNUAL GENERAL MEETING.

Fkuruary 3Rr), 1899.
J. J. H. Tfm.l, M.A , F.R.S., President, in the Chair.

Messrs. R. Holland and A. C. Young were appointed
Scrutineers of the ballot.

The following report of the Council for the year 1898 was
then read :

'"PHE numerical strength of the Association on the 31st of
■I December, 1898, was as follows : —

Honorary Members 16

Ordinary Members —

a. Life Members (Compounded) . . . • i5f>
/>. Old Country Members (5-;. Annual Subscription.) 7
c. Other Members (10s. Annual Sub cription) . . 366

Total -545

During the year twenty-three new mcmbcis were elected.
The (Council regrets that the Associatic^n has lost two members
by death : Sir Robert Rawlinson and William Walker.

The income of the Association for 1898 from all sources was
;;^239 1 8s 9d., and the expenditure was ^249 8s. id. There was
also a sum of ;^,2i 16s. 2d. due to the printers, against which
may beset ofT^ii 16s. 6d., the amount due for 1898, from the
advertisement contractor. It will be seen that for the first time
for several years the expenditure for the year has exceeded" the
income. This is due partly to the increased outlay on the
library, foreshadowed in the report for 1897, and still more to the
large amount required for printing the ]M<oc:ki:i)IN(;s. The
money, however, has been well spent, for it is a long time since
there has appeared in the PRocKEDiNr.s of thk Association a
pnper of such great interest and value as Trofessor Lapworlh's
Sketch of the deology of the J5irmingham District. The slight
falling ofl' noticeable in the receipts is due to the fact that fewer
new members were elected than in the previous year.

Five numbers of the ]*rocef.1)IN(;s, consisting of 254 pages of
text, 5 plates and 33 other illustrations, were issued during the
year 1898. 'J'hanks are due to the Authors for their contributions,
and especially to Professors Lapworth nnd Watts for their "Sketch
of the (ieology of the Birmingham District," published in the
August number. Your thanks are also due to Professor Watts
for Plate XIII., published in the November number.
May, 1899.]

ANNUAL GKNKRAI. MKtTINO.

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96 ANNUAL GENERAL MEETING.

The additions to the Library mainly consisted of serials.
Among those new to the Library may be mentioned The
Naturalist and the ** Bulletins of the Societe Linneenne de
Normandie." '

Some further arrears of binding have been made up. Among
other works, the Transactions of the following societies have been
bound and transferred to St. Martin's Library : Philadelphia
Academy of Natural Sciences (21 vols.), Yorkshire Geological
Society (6 vols.), Royal Physical Society of Edinburgh (6 vols.),
Berwickshire Natural History Club (8 vols.), also The Scottish
Geographical Magazine (10 vols.). A card catalogue is in course
of preparation, and can be seen by members at St. Martin's
Library.

The following is a list of the papers read at the evening
meetings :

" PalLcoIiihic Man," being the address of the retiring President, E. T.
Newton, F.R.S.

' Pebbly and other Gravels of Southern England," by A. E. Salter,
B.Sc, F.G.S.

" Fossil Sharks and Skates, with Special Reference to those of the Eocene
Period," by A. SMITH WooDWAKD, F.L.S., F.G.S., F.Z.S.

" Sketch of the Geology of the Birmingham District, with Special
Reference to the Long Excursion of 1898," by Professor C. Lapwokth,
LL.D,, F.R.S., with contributions by Professor W'. W. Watts, M.A., Sec. G.S.,
andW. J. Harrison, F.G.S.

"Contributions to the Geology of the Thame Valley," by A. M. Davies,
A.R.C.S., B.Sc, F.G.S. •

Lectures were delivered by L. L. Belinfanie, M.Sc, on
" Excursions in Russia made in connection with the International
Geological Congress, 1897"; '^y H. W. Monckton, F.L.S.,
F.G.S., the Rev. Prof. J. F. Blake, M.A., F.G.S., Aubrey
Strahan, M.A., F.G.S., and W. Whitaker, B.A., F.R.S., P.G.S.,
on " The Excursion Programme for 1898 " ; by Auhkev Strahan,
M.A., F.Ci.S., on " Observations in Lapland " ; and " Notes 011
Skye," by Horace Woodward, F.R.S. Your thanks are due to
all these gentlemen.

A Conversazione of a very successful character was held in
November. A full list of the exhibits will be found on p. 59 of
the Proceedings. Your thanks are due to the numerous members
who contributed to the success of that evening.

The following Museums and Collections were visited in 1898 :

March 5lh. — The Museum of Piactical Gev)lo,£jy, Jciinyn Street, under the

direction of the Pkesidknt, F. W. RujIlek, F.G.S., Curator of the

Museum, and E. T. Newton, F.R.S.
March 26th. — The South Kensington Museum (Science Division), Western

Galleries. Director, Prof. J. \V. Ji'DD, C.B., LL.D., F.R.S.
June 1st. — The collection of coins and other objects of interest found on

Dunwich Beach, at Mr. Lingwood's studio, Dunwich.

ANNUAL GENERAL MEETING.

The following is a list of excursions made during the past
year. Detailed reports will be found in parts 8 and lo of the
Proceedings, vol. xv :

April 7 to 12

(Basler)

April 23
May 7

(Whole Day)
May 14

May 21

May 28 lo June i
(Whitsuntide)

June II
June 18

June 25

(Whole Day)
July 2

July 9

July 16

(Whole Day)

July 23

July 28 to Aug. 3
(Long Excursion)

September 10

Bridportund Weymouth.

Reading.

Hillmorton and Rugby.

Ayot Green and HatBeld.

Penn and Coleshill.
Aldeburgh, Westleton, and
Dunwich.

Godalming.
Crowborough.

Sudbury.

Kingswood and Wallon-on-
the-hill.

Upper Warlingham

Worm's Heath.
Sheppey.

and

Cycling Hxcursioii 10 Purley,

Coulsdon, and Merstham.
Birmingham District.

Gravesend.

DI RECTO KS.

Rev. Prof. J. K. Blake,
M.A., F.G.S., W. n.
Iludleston, M. A.,

F.R.S., S. S. Buckman,

p /-• c

J. li. Blike, F.G.S.
Beeby Thompson, F G.S.,

F.G.S.
J. Hopkinson, F'.L.S.,

F.G.S., A. E. Salter

B.Sc, F.G.S.
W.P.D.Stebbing,F.G.S.
W. Whitaker, F.R.S.

Pres. G. S., F. W.

Harmer, F.G.S., E. P.

Ridley, F.G.S.
T. Leighton, F.G.S.
G. Abbott, M.R.C.S.,R.S.

IIerries,M.A., Sec. G.S.
J. W. Gregory, D.Sc,

F.G.S.
W. Whiuker, F. R.S.,

Pres. G. S., W. P. D.

Stebbing, F.G.S.
W. Whit'iker, F. R.S.,

Pres. G.S.
W. Whitaker, F.R.8.,

Pres. G.S., T. V.

Holmes, FG.S., W.I 1.

Shrubsole, F.G.S.
Rev. Prof. J. F. Blake.

M.A., F.G.S.
Prof. C.Lapworth, LL.D.,

F.R.S., W, Jerome

Harrison, F.G.S., W.

Wickham Kin^,

F.G.S., T. Stacey WiU

son, M.D., M.R.C.P.,

Prof. W. W. Watts,

M.A., Sec. G.S.
G. K. Dibley, F.G.S.

The interest of the members in the excursions during the past
year has been fully maintained.

Your thanks are due to the Directors of the excursions and
also to the following ladies and gentlemen for assistance and
hospitality :

The Mayor of Bridport, at Bridport ; Mr. Aubrey Strahan
F.G.S., for illustrations for the April Circular; Mr. Llewellyn
Treacher Jit Reading: Mr. Young, of Rugby ; Mr. W. H. AVilliams,

CHxVS. BARROIS ON

THE GEOLOGY OF CENTRAL I5RI ITANV. IO3

synclinals contain the more recent beds, while the anticlinals
expose the older beds.

The sketch-map (Fig. i) will show at a glance the three
principal folds enclosing rocks of Devono-Carboniferous age (the
basins of Laval, AngcV?, and Ancenis), and the two principal anti-
clinals corresponding with uplifts of pre-Cambrian gneiss (Folds
of L^on and Cornouaillcf). - ' ;:: /*• .

A number of other less impditstnt wrlrikte;5 occur correspond-
ing to many undulations of the Siliirian "and 4)re-Ca"mbrian
formations, but for our present purpose these ma/be ntglfcted.':
The most important amongst them is the St. Malo anticline, as '
seen in the sketch-map.

We may thus acquire a general idea of the structure of
Brittany in a single excursion by passing from north to south, and
from one anticlinal to another, across the several synclines. It
will, however, be preferable to make two parallel traverses,
because of the scarcity of exposures, this scarcity forming the
principal difficulty in surveying the country, where aamp lowlands
with a luxurious vegetation alternate with level tracts of bare
moorland.

To understand the geology of Brittany, however, it will not
suffice to consider only the succession of sedimentary rocks, which
liave been piled up during the pre-Cambrian and Palaeozoic
periods to a thickness of many thousand feet. Episodes of con-
temporaneous volcanicity took place at certain definite epochs
^luring these different periods, and they recall the grand
phenomena which have been described by Sir A. Geikie on the
other side of the Channel. They will occupy our attention but for a
moment, but, in spite of their historic interest, their tectonic
importance is small when compared with the position occupied
^y the deep-seated masses of granite and diorite, and with the
«-61e which these play in the structure of the country.

In this outline, therefore, it will be convenient to give first of
^1 a rapid review of the succession of the stratified rocks which
^nter into the structure of the area ; we will next consider the
<:ontemporaneous volcanic phenomena, and finally give some
<lescription of the deep-seated intrusive masses.

THE LOCAL ROCK-FORMATIONS.

The Tertiary series, from the Eocene to the Miocene,
exhibits a fair number of fossiliferous beds which are sometimes
very rich, but these deposits are limited to the neighbourhood of
the valleys, and it is only the Pliocene which has a wider extension.
The Tertiary outliers rest directly on the Palaeozoic rocks without
any trace or indication that deposits of Mesozoic age ever existed
between them.

I04

CHAS. BARROIS ON

Devonian.

The following is the succession of the Palseozoic and Archaean
rocks :

Carboniferous 4. Shales and conglomerates of TeilU.

3. Sandstone of Mouzeil with coal-seams.

2. Shales of Chateaulin, with the Profiuc/uS'lAmcstone of

Ou^non.
lb. Porphyritic tuffs,
la. Conglomerates an«l pbrphyric tuffs.

7. Shalest of Hostellct.

6. Shiilefe of Traouliors,

5. Shales of Porsguen.

4. Grey wacke of Fret.
^ 1 f r? ( Limestone of N^hou.

3. Greywackeof Faou | Un^estone of Erbray.

2. Sandstone of Gahard.

1. Shales and Quartzites of Plougastel.

4. Nodular Shales with Cardioia inter rupta.

3. Ampelites of Polign6.

2. Phtanitesof Anjou.

1. Sanil stone of Bourg-des-Comptes.

8. Limestone of Rosan.

c J X c c r- Til ' Redon Sandstone.

7. Sandstone of St. Germam-sur-Ille ^ g^ p^^^^^,^ gj^.^,^^

6. Slates of Riadan.

5. Sandstone of Chatcllier.

4. Slates of Sion.

3. Armoriran Sandstone.

2. Felspalhic Samlstoiie of Frc'jhel.

1. Conglomerate of Lnjuy.

3. Green or purple Flags.

2. Shales and Haggy Ouarlzites, with dolomitic Limestone^

1. Conglomerate t)f Motilfort and Hr6hec.

3. Green Flags of Neant.

2. Shales, Limestones and Conglomerates of Gourin.

1. Shales of St. Lo and of Lamhallc with Phlatiitcs.

3. Crystalline Schists of Groix.

2. Mica-Schists and Amphiboliles of Audierne.
I. Gneiss of Quimperl6.

Silurian.

Ordovician.

Camhrian.

Rriovfrian.

Arch/1«:an.

Archaean System.

The formations referred to the Archaean, crop out in two long
east and west bands in Leon and Cornouaille. Three principal
lithological divisions have been made, the types of which are
taken from the southern band; these are (i) the gneiss of
Quimperlc, (2) the mica-schists of Audierne, (3) the crystalline
schists of Groix.

I. Gneiss of Quimperlc. — This stage forms a continuous band
from Finistere to the Loire, and it will be seen at Auray. It
consists of granitic or granitoid gneiss, coarse grained, with white
or pink felspar, with much black mica in spots or in gneissic
strings, and with granitoid and corroded quartz, the mica being
sometimes replaced by fragmentary amphibole. The bands of
gneiss alternate with interstratified layers of schist and amphibolite,

THE GEOLOGY OF CENTRAL BRITTANY. lOS

and pass into gneissic granites which penetrate them in the
fashion of intrusions.

2. Mica-Schists of Audierne, — ^These mica-schists alternate with
subordinate beds of fine-grained gneiss, with others of amphibolite,
pyroxenite, eclogite, serpentine, chlorite-schist, and mica-schists,
and include interstratified masses of intrusive crystalline rocks
(fibrous and ribboned gneisses, halleflintas, and gneissites).
These subordinate rocks may have been injected into the mica-
schists; they actually form with them long parallel bands, which can
be followed from one end to the other of the southern plateau
of Brittany, from the Isle of Sein to the Loire. In the L^on
district this stage appears to form the base of the Archaean
series, and in this, massive bands of a white leptynite alternate
with the gneisses, mica-schists, and amphibolites.

3. T%e crystalline schists of Groix are a series of schistose
rocks, including micaceous, chloritic, chloritoid, and car-
bonaceous schists, with sillimanite schists remarkable for the
variety and abundance of heavy minerals which they contain
(staurotide, garnet, magnetic iron, etc.): there are also sub-
ordinate bands of graphitic quartzite, of sericite-quartzite, of cipolin
(pyroxenic marble), and of hornstone.

The boundaries of this stage, both above and below, are still
very obscure ; we have never been able to see them, and indeed
their very existence may be called in question. The three
divisions can certainly be distinguished by their lithological
characters, btit their succession is based only upon their constant
order of superposition, which is the same in Brittany as in many
other countries. No one, however, has seen the Brioverian strata
in Brittany resting unconformably upon an eroded surface of the
gneissic rocks ; and the rocks known to occur as pebbles in tlie
IJrioverian conglomerates are not Archrcan gneisses, but (juartz,
granite, granulite, and quartzite, that is to say, rocks identical with
those of the Brioverian itself.

It must be confessed that the greater antiquity of the Archrean
gneiss, though here admitted, is only a hypothesis. There are
even reasons for believing that the theory which regards all the
gneisses of Brittany as metamorphic products, dating from the
beginning of the Brioverian period, makes a nearer approach to
the truth.

Brioverian System.*

Above the Archaean gneisses and crystalline schists we find
a series of beds which are clearly sedimentary, unfossiliferous
shales, sandstones, and conglomerates, which were described by
the early geologists under the name of the Phyllades dc St. LCk
The lower limit of these St, L6 phyllades, which are more conveni-

* From the ancient name of St. Ia) (Hriovera).

io6

CHAS. BARROIS ON

ently termed the Brioverian system, is, as we have seen, unknown.
No one has yet been able to discover any unconformity in Brittany
between the Brioverian and the more ancient rocks ; on the con-
trary, there appears to be everywhere a stratigraphical and litho-
logical passage from one to the other, so gradual and insensible
that the line of division is purely subjective, and has been drawn
at different horizons by different surveyors on the staff of the
Geological Survey of France.

The Brioverian deposits are succeeded unconformably by the
Cambrian conglomerates of Montfort, in which their debris is
found as derived pebbles. We agree with Dufrenoy, who founded
the system of St. L6, in thinking that the Brioverian corresponds
with the Longniyndian ; but only a fortunate discovery of fossils
can determine whether we should class the Brioverian as Cambrian
or pre-Cambrian.

Whatever may be their relative age, the study of the divisions
of the Brioverian presents great interest, because it involves the
history of the first sediments and of the first volcanic eruptions in
Brittany. This series appears to attain a thickness of five kilo-
metres, and furnishes, moreover, forcible testimony to the power
and unlimited extent of contact-metamorphism at a great depth.

Recent researches have shown that the seas in which the

Brioverian sediments were

Fig. 2.. — A Deformed Granitic
Pehhle (G), with two Quartz
Veins (Q) in the schistose
Conglomerate or Cesson.

deposited were already differen-
tiated in Brittany. ^ Three dis-
tinct contemporaneous facies
can be distinguished in pass-
ing from north to south — facies
which can be followed inde-
finitely toward the west and
east — constituting the three
massifs of Tregorrois, of St.
L6, and of the Basse-Loire.
The massif of Tregorrois is
confined to the north of Brittany; it includes shales and
quartzo-phyllades, with interstratified eruptive rocks (porphyrites
and diabases) and conglomerates. The whole group, however, is
often replaced by alternations of micaceous and hornblende-schists.
The massif of St. Li\ stretching from the Bay of Douarnenez,.
in Finistere, to St. Lo, in Normandy, exhibits the following
divisions in the central area in descending order :

g /3. Green fluo^s of Ndant (.r^).

fS. Shales.

Shales and conglomerates
Gourin {x^^ ...

^ i 4. Gonglomerate of Gourin.

-\ 3. Shales ami quartzo-phyllades.

I 2. Limestone of St. Thurial.

[i. Phy Hades.

Shales of St. L6 and of Lam- | 2. Shales with seams of black chert,
balle (*•) \ I. Shales, phylUtes and greywackes.

THE GEOLOGY OF CENTRAL DRITTANY.

107

The massif of the Basse-Loire presents a great development
of argillaceous shales, with intercalated beds of coarse arkose,
described under the name of the shales and arkoses of Bains.

These three types will be visited in succession during the
course of the excursion ; the central and most important mnssif is
not well exposed in the neighbourhood of Rennes, but the
section (Fig. 3), taken at a little distance from Rennes, gives
a better idea of the various members of the series. The super-

FiG. 3. — Section from Corps-Nids to the Morihan Mill.
(Scale, ^
M** Morihan xoo TEtang M'* de Montagu Corps-Nuds

S.W.

N.E

S.P., Purple Shales ; P.P., Purple Cambrian Conglomerate ; X, Phyllades
of Su Ld; P, Gourin Conglomerate; C, Corps-Nuds Limestone;
G, White Brioverian Sandstone.

position of the conglomerates of Montfort, as indicated in this
section, will be seen in the course of the excursion at Pont Rcan,
in the valley of the Vilaine (Fig. 4).

Cambrian.

None of the Cambrian faunas, neither of Olenellus, Para-
doxides, or Olenus, have yet been found in Brittany, and if any
deposition of sediment took place at these epochs, they arc
represented by beds which are destitute of the characteristic
fossils. The most ancient fauna hitherto recognised is that of the
Armorican sandstone of Ordovician age.

In the absence of palaeontological evidence the limits assigned
to the Cambrian are necessarily very arbitrary. For a long time
the Brioverian was included in it, but at the present day only the
following unfossiliferous beds are referred to the Cambrian.

These beds exhibit remarkable local developments in the
different massifs with great differences of thickness and of litho-
logical composition. The following are the principal divisions
that have been recognised, in descending order :

6. Green and purple shales, and sandstones with Lingula criei.
5. Quartz porphyry of Pors-Even (lava flows).
4. Felstone of Arcouest, consisting of many successive outbursts.
3. Porphyrite of Kerity, with volcanic tuff.

2. Green and purple slates, nodular flagstones, dolomilic limestones and
quartzites of Plouezec and Mayenne.

I . Conglomerate of Montfort and of Brchec.

io8

CHAS. BARROlS ON

X
H

O
-I

a:
u

Station de
Plccbatel.

Landes de
Uagaroii.

Lc Chatellcr.
Kiadan.

Polignd.

FloiirK-dus-
Coinptcs.

Ciuichcn.

Travenzoi.

l^ille.

Vm C

O ri

V Xi

rt E
c75q3

Sic/)

■J- J <

IVnt-Rcuii.

Both the volcanic
rocks and the limestone
bands, which occur in
this series, are wanting
in the Vilaine section
(Fig. 4), where the
clastic rocks attain their
greatest development.
We shall see their ex-
posures in the Br«§hec
section (Fig. 5, Bay of
St. Brieuc), but they
have their greatest de-
velopment to the east,
in the Coevrons and the
Charnie, where they
have been described by
M. (Ehlert.

Ordovician.

In the central part
of Brittany the Ordovi-
cian exhibits three prin-
cipal divisions, which we
will examine in order.

The Lower Ordo-
vician consists of the
well-known Armorican
sandstone, a mass of
white sandstone from
1,600 to 2,600 feet
thick, which plays an
important part in the
orography of Brittany
(Fig. 6), but is poor
in fossils. It includes
several distinct lithologi-
cal subdivisions.

1. At the base are
the Co ftgloffu rates of
Ert/iiVy which contain
fragments of hard sedi-
mentary and eruptive
rocks derived from the
subjacent Cambrian and
Brioverian formations.

2. Above these come

THE GEOLOGY OF CENTRAL BRITTANY.

109

felspathic sandstones, coarse-
grained rocks without fossils,
which will be seen in the
neighbourhood of Brehec.
Southward, in the valley of
the Vilaine, they are repre-
sented by very different sand-
stones or grits without fel-
spar (gres du Grand-Gouin).
These should correspond
Mrith the Tremadoc Beds.

3. The Armorican sand-
stone proper (or pres du
Toulinguet) consists of sand-
stones in more distinct beds
^temating with some shaly
layers. This division is
rnore fossiliferous, yielding
•ScoliteSj BtlobiteSy Lingula,
-^inoboluSy Asaphus and
x^arious Lamellibranchs
( Actinodonta^ Cte no don ta^
^^edonid). A study of the
^auna shows more analogies
^vrith that of the Arenig than
"^rith that of the Tremadoc.

Middle Ordovician.
The stage of the "schistes
^'Angers" presents a series
^of black slates, interrupted
iDy occasional beds of sand-
stone, the thickness of which
^»ometimes increases at the
expense of the slates. The
following subdivisions can be
distinguished :

4. Bed of oolitic iron-
stone.

4a. The Sion slates with
'Synhomalonotus tris ta n / ,
Asaphus guettardi, Calix
murchisonu This is the
^X)ne of geminiform Didymo-
grapti.

5. The Chatellier sand-
stone ; the stratigraphical
position of this can be easily
determined at Chatellier,

July, 1899.]

Pte. de la Tour

•J
O

»
w
(A

u.
O

H
I

Brtfhec Bay

"3}

c
o
O

C/30

10" "O

tea

c3s

C <^

Pte.:de Br^bec

CHAS. BARROIS ON

THE GEOLOGY OF CENTRAL BRITTANY.

Ill

lear Bourg-des-Comptes. M. Lebesconte has found fossils in it
t Thourie.

6. The Riadan slates with Trinucleus pongerardi. These
lates are not easily distinguished from those below when the
iandstone is wanting.

Beds 4 and 4a correspond with the Llanvim series. Beds 5
ind 6 with the Llandeilb.

Upper Ordovician (7). Sandstones of St, Germain-sur-Ille^
)f Redon (in part), of Raguenez and Kermeur, with Acaste incerta^
Synhomaionotus aragOy and Trinuclei \ zone of Diplograptidse.
Fhese sandstones alternate with slaty beds of greater or les?

—Section of the Ordovician Beds around Poligne, bt M. Lebesconte.

tlitcs, H, Grits of Bourg-des-Comptes ; G, Slates of Riadan ; F, Sandstones of
Chatellier ; E, Slates of Sion ; D, Armorican Sandstone, Iron-stone.

{^Bhck kindly Unt by the Geological Society ^ France,)

lickness \ they break up more easily than those below into
mdy flags with characteristic parallel faces. They correspond
3 the Glenkiln Beds.

The Upper Ordovician in Finistere has been divided into
MTO portions by M. Kerforne, the shales of Raguenez at the base
nd the Kermeur sandstone above, divisions which in the
entre of Brittany are represented respectively by the red and
reen slates of St. Perreux and by the sandstone of Redon. It
I succeeded directly at Redon and Bourg des Comptes (Fig. 4) by
le sandstones and slates of the Upper Silurian, which differ but
lightly in their lithological characters. Thus it is very difficult to
etermine the plane of separation between the Ordovician and
ilurian systems in that part of Brittany which will be visited
y the Association, but it is much more clearly marked in Finistere
nd in the Maine-et-I>oire, where it is found to coincide with the
orizon of the limestone of Rosan. The accompanying section

112 CHAS. BARROIS ON

(Fig. 7) shows how the beds are exposed in the neighbourhood
of Polign^.

8. Limestone of JRosan, with Trinuckus^ Orihis actonice^ and
Triplesia spir if er aides ^ fossils which lead us to regard it as
the equivalent of the Caradoc. Interstratified with these cal-
careous rocks there are lava flows, fragmentary material, tuffs and
other contemporaneous eruptive rocks. These are, moreover,
limited to this horizon, of which they are characteristic in western
Brittany.

Silurian.

The Silurian of Brittany is easily distinguished as a whole
from the slates and sandstones of the Ordovician, by its lithological
characters. Coarse, clastic deposits, such as grits and conglom-
erates, become rare ; contemporaneous eruptive rocks are absent,
we find thin beds denoting a facies of deeper water, nodular
Orihoceras - limestones, carbonaceous slates with Pteropods
{Hyalites) and cherts with Graptolites. The formation thus
exhibits that prevailing character of carbonaceous slate with
nodular Orthaceras-Xvcti^'sXoTt^^ which it maintains throughout the
whole of the great central-European area. The number of species,
moreover, which it has in common with the Silurian (E.) of
Bohemia and of England is greater than in the case of the
Ordovician.

The following sub-divisions have been recognised in the
Silurian of the valley of the Vilaine.

1. Sandstone of Bourg-des-Comptes and of Redon (in part).
This is unfossiliferous, and has been confused with the Ordovician
sandstone, from which it is hard to separate it when the Rosan
limestone is absent. It is penetrated by a larger number of
quartz veins, it is less gritty, and includes thin layers of carbon-
aceous shale.

2. Phtanites of Anjou, Cherts in thin laminae of a few centi-
metres thick, but attaining a total thickness of 65 feet. The
rock is remarkable for the absence of quartz-grains and of other
terrigenous debris, and consists essentially of organic and
chemically-formed matter. It contains about 70 per cent of
silica in various states with 10 per cent, of carbon, both equally
derived from the remains of contemporaneous organisms, such as
Radiolaria with opaline tests and Graptolites with a chitinous
polypary. Sections of Radiolaria are sometimes seen in the
thin laminae; the Graptolites are few in number, but are very
well preserved ; they include Monograptus lobiferuSy Diplograptus^
Climacograptus, Cephalograptus^Rastrites \ a fauna characteristic of
the Llandovery.

3. Ampelites of Poligne, — Fine slates, without fossils, containing
intercalated beds of ampelitic (carbonaceous) slate with Graptolites.

THE GEOLOGY OF CEXTRAL ERnTAXY. II3

Sucfa is the zone of Poli^ne contaLfning Af:=m^-grjif>hts ^-nusms^
Lapv., Jf, friodom^ Broonu M. cmt^r^utus^ tit. spraiis^
DiplografiMS faltmnts^ Bairr. and CffhaZcp-aptus f:Emmt^ HK, and
corresponding to the sommit of the Tarannon Beds^

The carbonaceous sdiisis of Menaidais and AndooiEe b^ot^
by their £iiina to the Wenlock age — Mymi^^attus priin£ym^ Ji.
galaensis^ M. ruatrtomemsis, J/1 iwrnerrmMi^ Sf. a^mlituns^ and
RetioliUs getm/aamMS.

4. Nodular slaUs 'sritk CarJi-jla imi€rrvpta. These are poor
in fossib but include some lavers of spheroidal siliceoKalcareous
nodoles with Orihoctras %iyhUeMm^ Barr.. O. nthamnulan.^ MuensL,
Bdbozoe atumtaia^ Barr^ CardtWa imierrmfta^ Sov.. Mjtiius esitriemSj
Barr.y Pamemha hatmiSs^ Barr., llasia ims^ms^ Barr.. PUrinia wurtL,
Barr^ and DuaUma ucunda^ Barr^and many Graptotites of WenlodL
species. It is a Caona of Orthoceiaiites. Graptotites and thin-shdled
Lamellibranchs, and is remaii^ably de6cient in Trilobites and
Biachiopoda.

Devonian.

The higher Devonian beds, which are thin and pelagic in
diaracter, occur only at a few places ; the lower stages are thicker
and consist of coarser-grained rocks.

1. Shales and quartzites cf Pleygasul^ a thick mass of alternate
ing beds, less fosfliferous than those above, and attaining their
greatest development in the west of Brittany (=Gedinnien).

2. Sandstone of Gahard^ a white sandstone with layers of iron-
stone, containing Orthis monien^ Spiri/er felScOj Homahmotus^
and many Lam^branchs (^Taunusien).

3. Greyw(uke of Sthau. Bluish gritty shales alternating with
brown greywackes and lenticles of blue limestone ; these beds
form a continuous band from Brest to Laval. Fossils are
abundant in the limestone lenticle of Bois-roux. The Nebou
fauna includes : Spirifer hystericus^ Schlt., Athjris undata^ Defr.,
Chonetes pUMaj Schnur. (zone of Spirifer h^rqrnitz). Hie best
localities described by M. CEblert occur near LavaL The lime-
stone lenticles which yield the fauna of Erbray (zone of Sp.
prinurvus) are older than that of Bois-roux, and are better
developed in the basin of Angers than in that of Laval or of
Finistere.

4. Greywache of Fret^ with Phacops potieri^ Bayle, Spirifer
auriculatus^ Sandb., and Sp. paradoxus^ Schlt, is seen near St
Aubin d'Aubigne (zone of Spirifer paradoxus).

5. Slates of Porsguen with Anarcestes subnautilinus^ Schloth.
Bifida lepida, Goldf. (=Eifelien).

6. Slates of Traauliars with Rhynchonella pugnus. Mart,
ReceptacuUtes neptuni^ Defr. (=Frasnien).

7. Slates of RosteUec with pyrito-siliceous nodules, yield

114

CHAS. BARROIS ON

c
o

in .

en 2

«A

otn

^g
J5*§

3 bo
2 =

« «

Paradiceras ver-
nem'/i, Muenst,
Tarmoteras sim-
plex y V- Buch.
(=Famennien),
The portion
of Bri ttany
which will be
traversed by the
Association is
unfavourable
for the detailed
study of the
Devonian. To
those who may
wish to make a
more prolonged
examination of
this formation
we should re-
commend the
neighbourhood
of Laval or of
Brest

Carboni-
ferous.

The oldest
Carboniferous
sediments in
Brittany are de-
posits of erup-
tive material
spread out on
the old sea floor.
The period is
characterised in
this region
(studied by
MM. E. and L.
Bureau) by
alternations of
terrestrial and
marine condi-
tions, as well
as by grand
and powerful

THE GEOLOGY OF CENTRAL BRITTANY.

volcanic phenomena ; it is a period of great eruptions and of great
eartli-movements.

I. Parpkyroids. In the west of Brittany we find shales and
conglomerates^ with porphyric material and porphyritic tuffs. In
the central area there are shaly rocks crowded with crystals of
felspar, and of bipyramidal quartz (porphyroides and blavierites\
which attain a thickness of 3,000 feet (Er^ac). Some beds
exhibit a structure like that of microgranulite and of quartz
porphyry ; but others contain pebbles, and are clearly of clastic
origin (as at La Barillere).

Fig. 9. — Sketch-map of the St. aubin d'Aubigne Massif.
(Scale ^5^

2. Slates of ChAteaulin, These are bluish grey, fine-grained
shaly beds with Productus (at Lande-Marie in the Rennes sheet),
alternating with layers of greenish grey felspathic sandstone with
▼^etable impressions (in the Chateaulin sheet). They include a
thick lenticle of limestone worked for marble in the quarries of
Quenon (Fig. 8); the beds are vertical and fossiliferous, affording
Phillipsia^ Productus^ etc. The section (Fig. 8) shows how the
beds are broken in the synclinal troughs of Central Brittany.
The accotnpanying sketch-map (Fig. 9) of the region shows how
the faults- can be followed and traced in the field.

Il6 CHAS. BARROIS ON

The slates of Chateaulin are represented in the basin of
Ancenis by greywacke with plant remains, corresponding to that
of Thann (Culm).

3. Mouzeil sandstone with coal seams, comprising alternating
beds of shale, sandstone, conglomerate and porphyritic tuff
(pierre carr^e). The conglomerates contain pebbles of quartz,
gneiss, diabase, Silurian quartzite, Carboniferous chert, and grey-
wacke. The flora is that of the greywacke of the Culm, Bomia
transitionis^ F. Roem ; Sigiilaria minima, A. Brg. ; Knorria
imbricata, Stern. ; Lepidodendron veltheimianum, Ung. ; Archct-
opteris virleti, Stur. ; Neuropteris antecedenSy Stur.

4. Shales of TeiWe, crowded with plant remains, and alternating
with" beds of conglomerate, containing pebbles of quartz and
Carboniferous greywacke. Fossils : Cordaites borassifolius^ Gein. ;
Alethopteris serlii, Goepp. ; PrepecopUris plumosa. Grand Eury ;
Sphenopteris furcaia, A. Brg. ; Asterophyllites longifolia, A. Brg.
A still higher horizon with Didyopteris subbrongniarii. Grand Eury,
has also been recognised by M. Bureau at Ecoul6. The con-
glomerates of this age at Quimper contain pebbles of granite and
of various gneisses.

II.— ERUPTIVE ROCKS.

As the route was not chosen with the special view of studying
the contemporaneous volcanic rocks, the Association will not be
able to see much of them during the excursion. We shall there-
fore confine ourselves to enumerating the principal eruptive
episodes, without describing them in detail.

Briaverian : Diabases, epidiorites, porphyrites, and variolites
of the Tr^gorrois.

Cambrian : i. Pyroxene -porphy rite of Kerity ; flows of
porphyritic glass, tuffs, and agglomerates.

2. Orthophyres of Arcouest, comprising many successive
outbursts, the veins of which cut and displace one another.

3. Quartz-porphyry of Pors-Even ; microgranulites ; micro-
pegmatites ; sphaerulitic petrosiliceous and rhyolitic porphyries

Upper Ordovician : i. Quartz- porphyries of the Basse-Loire.
2. Diabases and porphyrites with tuffs and ashes at Rosan.

Lower Carboniferous \ i. Quartz-porphyries, porphyroids, and
porphyric tuffs. 2. Diabases, porphyrites, and porphyritic tuffs.

Upper Carboniferous : Dykes of diabase, so numerous that
before denudation their lava-flows must have covered the whole
country.

III.— INTRUSIVE ROCKS.

In the number and variety of its granitic masses, in their
diversity of structure and composition, in the great faults which
have brought deep-seated portions to the surface, and lastly in the

THE GEOLOGY OF CENTRAL BRITTANY. II7

depth to which the country has been eroded since the Carboniferous
period, Brittany offers remarkable opportunities foi the study of
intrusive igneous rocks. The granites intruded at different
epochs, ranging from the Archaean to the Carboniferous, do not
always show the same relations to the surrounding strata, and a
study of these relations throws light on the mechanism of
their outbreak.

But while the relations of the granites to the Palaeozoic
sediments are similar to those of other countries, such as England
and Norway, where Palaeozoic rocks repose directly on the
crystalhne schists, we find in Brittany other facts and special
conditions between the Cambrian and the Archaean, in a clastic
formation more than four kilometres in thickness. In these deep-
seated Brioverian sediments the Carboniferous granitic intrusions
have here been subjected to very considerable pressure, due to
the weight of the overlying sediments, and the modifications
produced have consequently been more intense ; it is in these
beds that the phenomena of metamorphism and injection attain
their greatest development.

Putting aside the general problem so ably discussed from such
very different points of view by Michel L^vy and Brogger,
we shall limit ourselves, in what follows, to the description of
mere facts, which may be observed during the progress of the
excursion.

(a) The granite mass of St, Marcan and its gtanulitic aureole
(Fig. 10).

This mass is circular in form and occupies an area of about
50 sq. kil. It has forced its way into the Brioverian slates and
greywackes which have been transformed near the contact into
spotted and knotted schists, leptynolites, chiastolite slates, and
micaceous greywackes. It is formed of a medium-grained, homo-
genous, massive rock of a bluish-grey colour, rich in white
orthoclase, greenish oligoclase, microcline, and a black mica
which is present in excess of white mica. The amount of white
mica increases as the margin is approached, and at the margin
the rock can no longer be distinguished from a muscovite
granulite.* Smaller masses, Mont Dol, Tombelaine, and Mont
St Michel, consisting of granulitic rocks, aplites, and pegmatites
occur as satellites to the main mass in isolated knobs.

This fact of differentiation is better seen round the mass near
Ding^, and, better still, round the granitic masses of Guem^n^; it
is genera], but of unequal extent.

(If) Granitic masses of the Morbihan, — Many granitic masses
occur in the Morbihan ; they are so numerous and so like each
other that no doubt can exist as to their genetic relations. Do
these different masses represent, as in certain countries, successive

^ ^ It must be mnembefrd that French authors use the term ** granulite " for muscovite
gnmite, and even for a granite with two micas. — £u.

ii8

CHAS. BARROIS ON

intrusions, emitted from the same reservoir during a process of
slow differentiation, or do they, rather, correspond to the different
parts of one liquid mass, consolidated at different depths and
at different times ?

They differ more in the forms of their contours and in their
modes of distribution than in their lithological characters. The
different masses have many lithological features in common, and
share a general tendency to arrange themselves, like beads on a
string, in a series of elliptical areas, extending from north-west to
south-east. These strings of granitic beads, so to speak, can be

Fig. 10.— Section through the Granitic mass of Mont-Dol.
(Scale, ^jfhsTf)

X Brioverian. y Aplites and Granulites. G Granite.

followed for a distance of 300 kil. along the southern margin of
Brittany. The direction of the moniliform lines corresponds to
that of the folded Palaeozoic rocks and to that of the principal
tectonic features, such as faults and the crests of folds. But
while in the N.W. of the district the granitic masses are exposed
in the areas qf pre-Clmbrian gneisses and mica-schists, in the
S.E. they occuf also in the Silurian area. It is easier to study
them in the Palaeozoic districts rather than in the pre-Cambrian
area ; we shall therefore select the Palaeozoic S.E. of Brittany for

THE GEOLOGY OF CENTRAL BRITTANY.

119

CI>

I20 CHAS. BARROIS ON

detailed description, and generalise the results so far as the western
pre-Cambrian part of the country is concerned.

The field thus limited is represented on the map (Fig. ii),
which shows the termination towards the E. of the following three
parallel granitic zones :

1. Mass of St. Jean Brevelay.

2. Mass of Lanvaux.

3. Mass of Grandchamp.

The mass of St. Jean Brevelay is the most northerly. It
extends, on our map, almost from Ploermel to Pontivy, with an
area of about 200 sq. kil.

The mass of Lanvaux, situated to the S. of the one above
referred to, and of greater importance, forms a vast ellipse more
than 90 kil. in length. Moreover, it does not stop where last
seen at the surface, for the granite which appears to the west of
Angers, 80 kil. further to the east, may be regarded as an apophysis
of the same deep-seated mass. The analogies in composition and
structure of the granites of these two masses, the similarity of
their action on the surrounding rocks, and lastly their occurrence
in the centre of the same anticlinal, establishes this fact of their
relationship.

The mass of I-^nvaux must therefore be regarded as the
longest in the district, for it extends, either at the surface
or beneath it, fiom Lanvaux to Angers, a distance of 200 kil.,
and therefore from one end to the other of our map (Fig. 11).

The mass of Grandchamp, situated to the south of the fore-
going, extends from Pluvigner to Allaire, with an area of 300
sq. kil. It is shorter than that of Lanvaux, but, like it, reappears
after an underground course of 40 kil. in the smaller mass of
Nozay, which is lithologically identical with that of Grandchamp,
ind situated in the centre of the same Silurian synclinal. There
are therefore the same reasons for referring the granite island of
Nozay to that of Grandchamp as there are for correlating the
granite of Angers with that of Lanvaux. The probability of their
continuity underground is increased by the curious metamorphism
of the Silurian sediments into crystalline schists in the intervening
portion of the synclinal as indicated on the State Survey map of
St. Nazaire.

The continuity underground of the elliptical masses above
referred to is proved both by the similarity in their lithological
characters and by their mode of occurrence. It is more difficult,
and at the same time more interesting, to ascertain the relations
of the three zones to each other. Some light may be thrown on
the matter by comparing them with reference to the mode of
occurrence of the granite, the age and nature of the metamorphism
of the beds traversed, and the structure and composition of the
intrusive rocks. But before proceeding to institute this com-

THE GEOLOGY OF CENTRAL BRITTANY.

121

parison it will be necessary to study the three masses in greater
detaiL

I. Mass of St Jean Brevelay, This mass is formed of a
coarse-grained granulite with two micas. Aplitic, fibro-schistose
and gneissose varieties may sometimes be observed on its
margins. It is situated in an anticlinal band in Brioverian slates,
which must belong to the upper part of the formation, because
the purple Cambrian slates are regularly exposed on both sides.

KiG. 12.— Map of the Eastern Extremity of the Gkandchamp

Massif. (Scale

3200n« t

Scfaute* ei gret

Sdutes et|rea

Granulite
•diisteuse

Grsmalite
poiphrroide*

Granulite
ffrmua .

A description of this mass has already appeared to which
Teference may be made {Ann, Soc, GeoL du Nord^ t. xv., 1887,
p. 16).

2. Mass of Grandchamp, This mass is allied to the former
in composition and most of its other characters, but it traverses
all the formations of the district from the pre-Cambrian gneiss to
the anthracitic slates of the Upper Silurian. The beds are
intensely altered with the development of the ordinary contact-
silicates, such as black mica, andalusite, fuchsite, garnet and
pyroxene. Felspar has not been produced in this outer aureole.

In the centre of the mass the granite is a coarse-grained,
massive rock, rich in white mica and containing quartz grains
which are generally terminated (granulite, French). Near its
margins this rock becomes porphyroid and presents some important
endomorphic modifications. On its southern border it becomes
foliated, the mica and other constituents being orientated parallel
to the foliation. On the northern side the change is somewhat
different (Fig. 13) ; there the black mica becomes more abundant,

122 CHAS. BARROIS ON

the constituents increase in size and the microcline occurs in large
Carlsbad twins, four or five cms. across, giving to the rock a
porphyritic character. The constituents are not distributed
irregularly, for even small exposures show that the porphyritic
crystals of microcline are arranged along undulating lines or
zones. Aplite sometimes forms local margins (Tertre Windmill),
but more frequently occurs as narrow veins.

From the differentiation of the magma and from the orienta-
tion of the elements of first consolidation along pseudo-fluidal
lines, near the margin, we must conclude that the consolidation
was progressive ; and that, commencing near the margin in a still
moving mass, it proceeded towards the interior across a magma
at rest. The foliated granulites on the southern border possess
a secondary schistosity, due to orogenesis, superimposed upon a

Fig. 13.— Section from St. Eutrope to

St.

Jacut,

(S-les^

,t».... H-deKoBlinion

«R.

♦•*♦■ ♦♦♦■•♦•■♦• ♦^•'-p--^

Vp Sm "Yp Sm Sjd

y* Granulite Sm Metamorphosed Silurian

yp rorph>Told Granulite S Silurian StraU

primary phenomenon of fluidity due to the conditions under
which the magma consolidated.

In the mass of Grandchamp the modifications of the granite
at the contact are not due to interchange of material between the
eruptive magma and the surrounding rock ; but only to the con-
ditions of consolidation which determined the orientation of the
constituents of the granite, their mode of grouping, and the order
of crystallisation. The enclosing rocks acted differently as regards
the conduction of heat and the transmission of pressure, but they
exerted no chemical influence on the eruptive magma. This
conclusion, however, is only applicable to this mass and to the
one previously described. It does not apply to the mass of

Lanvaux. ,. ^

The neighbouring small circular islets of granulite do not

show modifications comparable to those above described. They

may be regarded as the apophyses of more important masses

existing below.

3. The granite fnass of Lanvaux forms an elongated area,

parallel to the former, but differing in composition and structure.

It is usually foliated, and presents many varieties. ^'^ — -—

Massive

THE GEOLOGY OF CENTRAL BRITTANY. 1 23

gnuiite, rich in biotite, is worked for paving-stones in the eastern
portion of the area, near Bains, but the rest of the mass is
gneissose, and the dominant black mica is usually present as
debris; it is made up of alternating, more or less micaceous
bands which possess granular or euritic, gneissose and glandular
structures.

The granite of Lanvaux, unlike that of Grandchamp, does not
appear in contact with beds so high in the series as Upper
Silurian; it is limited to the area of the Brioverian rocks, which
form a long, elliptical anticline separating the parallel synclinal
tronghs of Redon and Malestroit.

The greyish slates alternating with beds of darker slate,
greenish grey greywackes, and beds of a white foliated arkose, are
exposed from one end to the other of the " Landes de Lanvaux,"
in the valleys of the Claye and of the Arz. The beds of arkose,
near the granite, are remarkable for the development of thick
sericitic membranes, which give them a gneissose aspect and
surround large grains of quartz (1-2 mms.), sometimes doubly
terminated, fragments of orthoclase and oligoclase, and also
fragments of black mica. As the granite is approached the slates
become nodular, and small plates of black mica and muscovite
are developed ; moreover, the felspars of the granite pass out into
the contact-rocks and transform them into felspathic schists con-
taining a little mica. The quartz in these schists is often arranged
in continuous ribbons.

The parallel structure of the granite-mass is in part due to
interstratified bands of a greenish grey, somewhat micaceous
schist Repeated alternations of more or less granular, gneissose
and schistose bands point to the conclusion that there has been
an injection of granitic sills between beds of schist, and do not
support the view that the phyllitic and schistose bands have been
formed by the dynamic metamorphism of the massive granite.

Comparison of the Three Granite Masses of the Morbihan, —
If, on consulting the map (Fig. 11), a comparison be made
of the three masses above described, it will be seen that the
Lanvaux-mass is enclosed in the deep Brioverian beds, far away
from the Hnes delineating the Silurian series.

The Grandchamp mass traverses Silurian rocks, while that of
St Jean Brevelay is in the neighbourhood of another band of
the same age ; the map, therefore, shows that the Lanvaux-mass
is enclosed in beds older than those surrounding the two others.
If, moreover, we make a section (Fig. 14) across the map it
will be seen that the Lanvaux-mass has not reached the general
level, but that the block has been brought up by two faults, which
have been traced upon the ground. If we recall the ideas
already acquired on the distribution of the sedimentary rocks of
the district, we are compelled to admit that before its abrasion by
atmospheric denudation the rocks forming this anticlinal block

124

•<

S
o

u
u

H
U

•<

^ (Mass of Lanvaux) f

I .*

c«

(/}

a
<

G
'rt

O
Vi

CO
u B

2 5

e .2

THE GEOLOGY OF CENTRAL BRITTANY. 1^5

were coYered by the whole thickness of the Silurian rocks now
only to be seen in the neighbouring synclinals.

These facts show, beyond all question, that the granite of the
masses of Grandchamp and of St. Jean Brevelay were consoli-
dated under almost the same conditions of depth, and those of
Lanvaux under different conditions and at greater depths, so it
is to these differences of depths, shown in the sections, that the
differences of composition and of structure between the granite
masses, described above, precisely correspond. There is, there-
fore, a reason, founded upon observation alone^ for believing that
the differences of composition and of metamorphic action in these
granites are to be attributed to the depths at which the consolida-
tion of the various masses took place.

It may be objected that these differences may be due to other
causes. Thus it is possible to suppose that the various masses
are not contemporaneous, or that they belong to two successive
intrusions of a magna undergoing evolution at a great depth. But
on comparing the two hypotheses it will be seen that ours has
the decided advantage of resting upon material facts ; although
it may not eliminate other objections. No observation actually
supports the idea that the three masses described could have been
formed by successive eruptions; we find neither ddbris nor
constituents of a first consolidation, mingled with the minerals of
more recent formation, nor rolled pebbles of these granites in the
various members of the sedimentary formations. Other masses
in Brittany have furnished examples of these facts ; their absence
in the district under consideration is but further proof ot* the
synchronism of these three masses.

The characters of the granite and the extent of its metamorphic
phenomena vary with the thickness of the covering cap and
consequently with the pressure under which the mass consolidated ;
they are also in relation with the nature and abundance of the
mineralising agents which accompanied the magma. The strati-
graphy of the Morbihan masses furnishes an example of this by
giving an explanation of the difference of the intensity and extent
oiihe felspathisation in neighbouring masses, sometimes separated
in the field by scarcely a mile.

Thus it is proved that in the masses which consolidated at
lesser depths, such as that of Grandchamp, the separation
between the Silurian and the granite is sharply defined, the
sediments are not felspathised, but transformed into crystalline
rocks with mica and andalusite without felspar, as is the case in
Norway and in the Vosges.

In the Lanvaux-mass, on the contrary, at the contact with the
granite, a persistent zone in which schists and greywackes become
charged with felspar, possibly by absorption or by injection, may
be observed. All the stages of this felspathisation may be
followed, and almost imperceptible passages between the felspathic
July, 1899.] 10

126 CHAS. BARROIS ON

schists and the granite itself may be observed; until, in the
presence of certain beds, it becomes a matter for discussion
whether they are granites, mechanically crushed and deformed, or
felspathic schists. Veritable gneisses are thus produced, in the
midst of which we find, here and there, more massive granites or
fragments of schists representing extreme stages of alteration.
The extent of the felspalhisation and the thickness of the
gneissification are therefore functions of the depth of the contact
observed, and permit, so to speak, of its measurement.

It becomes reasonable, therefore, to suppose that at greater
depths the contacts between impregnated sediments and granite
would present less and less difference ; and we are thus led to
believe with M. Michel Levy that there exists a deep zone where
there is complete continuity between the normal granite and the
gneissic border formed under the influence of the granite at the
expense of the earlier sedimentary rocks.

But whatever may be thought of this conclusion, the strati-
graphical examination of the granite-masses of the Morbihan
furnishes material facts which all theories must take into con-
sideration. Stratigraphical observation negatives the view that
the granite has been an intrusive plastic mass, elevating,
displacing and dislocating the superincumbent sedimentary rocks
at the time of its eruption. The great tectonic lines of Brittany
and the general plan of structure have not been disturbed by the
eruption of the granite ; the long bands of colour on the
geological map, the folds and faults which affect the normal
sedimentary masses of the east of Brittany, continue uninter-
ruptedly in the west, into the granitic portions of the country,
without disclosing any connection between the presence of the
granite and special dislocations or more complex structures which
do not exist in this district. The stratigraphical order of the
sedimentary blocks within the granitic areas prevents their being
considered as scattered fragments floating on the surface of a
granitic bath; for the sequence is normal and the included
masses lie along the same lines of strike as those of the sur-
rounding strata from which they have been derived. The
sections traced across the folded and faulted sedimentary series
of Brittany may be drawn continuously, in the portions replaced
by the granite masses, in the same way that they may be traced
in the field over those portions removed by atmospheric
denudation.

The construction of geological profiles across the country
does not enable us to distinguish the forms in space of the various
granitic masses, but it clearly brings out the fact that the existing
surface gives us sections in plan, of masses which consolidated
at different depths. These sections show that the phenomena
of contact-metamorphism, of injection, of assimilation and, con-
sequently, the composition and structure of the granites them-

THE GEOLOGY OF CENTRAL BRITTANY. 1 27

selves, are variable in one and the same district and round the
same centre ; and, further, that these variations are a function of
the distance of the section in question from the upper limit
reached by the magma durino; its ascension.

Granites of the Cdtes du Nord. — In the Cotes du Nord
there is evidence of the formation of granite at several successive
periods. The first, of Lower Brioverian age, is represented by
pebbles in the Brioverian conglomerates ; the second is found
as intrusive masses in the Brioverian rocks and also as pebbles in
Cambrian strata ; the third shows masses which cut the Silurian
series and are of Carboniferous age. These different occurrences
may best be studied in inverse order.

The Mass ofQuintin, — This vast elliptical mass, 50 kil. in length,
is composed, on its southern margin, of massive granite with biotite
and on its northern margin, of foliated granite with two micas,
passing into granulitic gneiss. These differences of structure
are, as in the Morbihan, in direct relation to the depth of the
enclosing rocks, massive granite being found in contact with the
Carboniferous series and the gneissose granite with the Brioverian.
Here, however, we may suppose, and there are even arguments
for believing, that the differences should be attributed to the
action of two successive eruptions.

This mass of granite is instructive in other ways ; it not only
furnishes information as to the difference both of kind and degree
of metamorphism on its different faces, but also as to the unequal
resistance to assimilation of the various sediments presented to it
An example of this is to be found in the neighbourhood of Pl^dran
at the contact of Jhe gneissose granites (gneiss granulitiques) and
the Brioverian shales. These rocks, east of Pl^dran, present the
usual characters of the St. L6 formation — ^argillaceous shales with
intercalated beds of greywacke and a few beds of hornblendic
rocks and graphitic phtanites.

On approaching the granite mass of Quintin, from the east
towards the west, the gradual alteration of the sedimentary rocks
may be observed ; the metamorphism of the argillaceous rocks is
seen to take place more readily than that of the graphitic
phtanites.

The shales pass successively into spotted schists ; into mica-
ceous schists, rich in biotite, etc., with a few macliferous and
sillimanitic patches ; then into felspathic schists, and finally into
granulitic gneisses; the passage is very gradual between the
different rocks. The gneisses contain all the constituents of the
granulites, associated with the remains of the schists in the con-
dition of continuous tissues enriched with streaks of black mica
and with patches of sillimanite. The tissues give to the granulitic
rock an interlaced structure, in which the wavy micaceous films
separate the lenticular amygdules of massive granulite with black
mica.

128

CHAS. BARROIS ON

The beds of graphitic phtanite are far less affected by meta-
morphic action than are the beds in which they occur ; and they
may be followed in the field, as shown upon the accompanying map
(Fig* 15)) which illustrates the fact that definite beds of phtanite
occur successively between schists, mica-schists, and granulitic
gneisses as they approach the granite ; the phtanite may be
traced into a massive quartzite as the schists pass into gneiss.

Some geologists would prefer to consider these granulitic
gneisses as crushed granite rather than as schists injected with
granite, but the question appears to be of minor importance in
view of the proved persistence of the bed of phtanite, neither

Fig. 15.— Map showing the contact of Granfte
NEAR Pledran. (Scale, rffDW)

V SQuW V V V V ^

G Granite, y Granulitic Gneiss of Brioverian Age.
xy Micaceous Brioverian Schists. Gr Graphitic
Phtanite of the Brioverian. x Brioverian Shales and
Greywackes.

disturbed nor dislocated, into the granitised mass. The granitic
magma has taken the place of the schist, but not that of the
quartzite.

The graphitic quartzite is the actual bed from which M.
Cayeux described the Radiolaria (Cenosphard) obtained
near Lamballe, 18 kil. distant. The age of the quartzite
is as clearly established as its sedimentary origin, since it forms
a well determined horizon in the Brioverian series, and is found
as pebbles at the base of the Cambrian. Its great development
in the Pledran district is accidental, and due to a folding, which
brings the same bed to the surface several times, as shown in
the section. (Fig. 16.)

2. The granitic mass 0/ St. Brieuc, — The granite of St. Brieuc
differs from those above described in structure, mode of occur-

THE GEOLOGY OF CENTRAL BRITTANY.

129

tc^ce, and age. It is more basic, containing amphibole, and

9^^:^a.sionally passes into diorite. It is older than the others, for

A ^^^"'^ ^ pebbles at the base of the Cambrian, whilst those

^^^cribed above cut Silurian strata, and are of Carboniferous age.

This granite is dioritic, sometimes massive and sometimes

S^^ssose, unequally rich in amphibole, with titaniferous iron,

apatite, zoned felspars passing from andestne to basic labradorite,

Pig. 16.— Section Showing the Folding of the Graphitic Beds

AROUND PLEDRAN, AND THEIR METAMORPHISM. (Scale, T5Tftrinj)-

ss.

N.E

G Granite. y Granulitic gneiss.

xy Micaceous schists. x Brioverian shale.

Graphitic phtanites (in black).

orthoclase rare, pyroxene rare, and quartz. It passes in its
massive varieties from the hornblende-granite of St. Brieuc into
the diorite of St. Quay. In the thin veins of the periphery
of • the mass it shows pegmatitic varieties, with crystals of
amphibole 5 cm. in length, besides other varieties passing into
microgranites.

The St. Brieuc granite is only seen in contact with Brioverian
rocks ; it presents endomorphic and exomorphic modifications
as extensive of their kind as those of the Morbihan mass. But
the modifications are no longer of the same type. The Brioverian
strata here are not composed of slates and greywackes as in the
Morbihan (facies of the phyllades of St. L6), but of alternating
beds of clay slates, graphitic phtanites, and basic flows (more
or less abundant) of porphyrites and diabases (facies of
Tr^orrois) ; it has become a complex formation composed
principally of green schists with actinolite, epidote and chlorite,
alternating with compact green hornstones {schistes pyroxeniques)
and foliated gabbros resulting from the transformation of massive
basic rocks, together with micaceous schists, staurolite schists,
leptyniteS; micaceous greywackes, and felspathic conglomerates.

13©

CHAS. BARROIS ON

Its appearance under this very basic facies is limited to a bow-
shaped band which corresponds, in the district we are considering,
to the Bay of St. Brieuc, as shown in the map (Fig. 17).

The map also shows the distribution of the pre Cambrian
hornblendic granite, and one sees that it is confined to the
area occupied by the preceding basic series, which it follows
closely.

It is believed that, in this coincidence, a relation of cause
and effect may be observed, and that the composition — unique in
Brittany — of this mass of dioritic granite, is due to the influence

Fig. 17. — Sketch-Map showing the distrihution of the pre-
Cambrian Hornblendic Granite and its Topographical rela-
tions WITH the Basic Facies of the Brioverian Strata.
(Scale, TaiminTTT-)

D Basic Facies of the Brioverian Series. G Hornblendic Granite.

of the Brioverian eruptive basic rocks, also unique, into the midst
of which the granite is intruded. We drew attention in 1889,
in the Puy-de-Dome*, to the analogy which exists between these
facts and those there pointed out by M. Michel Levy ; impressed
by the constant association in that district of calcareous hornstones
and diabase-diorites, and by the occurrence of an aureole of
hornblendic granite between the latter and the normal granite, he
concluded that the various rocks resulted from the endomorphism
of the granite, its composition having been considerably changed
by the assimilation of calcareous beds. In Brittany, in the
neighbourhood of Pontrieux and of An del, on ascending the
Trieux river, or in descending the valley of the Gouessan, one

* Bull. Sac» Ceol, Ftmnctt t. x\m, p. 917, 1890.

THE GEOLOGV OF CENTRAL BRITTANY. I3!

may follow the passage of microlitic rocks, porphyrites and
<liabases, into hornblendUc schists and epidiorites.

In the hornblende-schists of both valleys, on approaching the
granite, grains of felspar are developed, which gradually transform
»he rocks into a homblendic gneiss, a gneissose diorite, and
finally into a massive dioritic granite with amphibole and
biotite.

These massive crystalline rocks are well developed in the Bay
of St Brieac ; they present exceptionally ultra-basic types, such as
norites, homblendites, and even peridotites with hornblende,
analogous with those recognised by M. Lacroix at Pallet in the
Loire-Inf^rieure.

Numerous sections prove that the schistose hornblendic
homstones, and other associated Brioverian rocks, are disrupted
by the diorite and intimately mixed with it in the form of a breccia
with its angular elements in alignment ; occasionally the injection
occurs in slender, transverse veins, or more often following the
lines of foliation, which at the same time are penetrated in all
directions and in all proportions by the dioritic magma (see the
survey map Bande de Coetmieux),

IV.— GENERAL STRUCTURE OF THE DISTRICT.

The surface of Brittany consists of sedimentary and eruptive
rocks of Palaeozoic age ; the beds are much disturbed, and their
outcrops form long, narrow bands, which are seen following the
strike across the whole country in a west to east direction.

These great tectonic lines were determined by an important
folding movement of Carboniferous age ; but their formation had
been prepared beforehand during a long series of geological epochs.
This is proved by the coincidence of these lines with the former
basins of deposit, with the difference of facies, the transgressions
of the strata, and with the alignment of the successive intrusions
of the deep-seated magmatic masses.

The fundamental structure of Brittany is to be assigned to the
Carboniferous period. But the ruins only now remain; the relics
of the ruined structure appear to us eroded by the secular
action of atmospheric denudation. All the anticlinal arches have
been swept away by the irresistible action of time. The synclinal
depressions alone remain for our investigation — silent witnesses of
the great power of the mechanical deformation which folded,
strained, and fractured the rocks of the district.

The synclinal troughs, twenty-four of which are traced on the
detailed map of Brittany, no longer preserve the simple
symmetrical V-shaped form; they are reduced to deep and
narrow unsymmetrical depressions, into which the beds slowly
descended at the time when the crust was contracting. The

13^ CHAS. BARROtS OK TM£ GfiOLOGV OP CENTRAL RRtTTANY.

beds thus buried and preserved in these depressions are, as a
rule, specially broken and crushed on their borders, where the
greater faults of the country are found ; in the centre of the
synclines the beds show a uniform dip, and are, moreover,
traversed by subordinate faults, which break up the land into a
series of parallel inclined '* blocks " or lamellae.

The analysis of all the earth movements, of which traces have
been preserved in Brittany, shows that they are related to one
and the same continuous lateral pressure. This pressure acted
in the same direction during the whole of the PaJaeozoic period
on a zone of the earth's crust which was slowly subsiding.

For References to the Literature see Bull. GeoL Soc,
France^ ser. 3, t. xiv, 1886, and Ann, Soc, GeoL du Nord^ vol. i to
xxvii, Lille.

133

VISIT TO THE MUSEUM OF Mr. W. H. HUDLESTON,
M.A., F.R.S.

Saturday, March iith, 1899.

iRepcrt by Prof. J. F. Blake, M.A., F.G.S.)

The members of the Association to the number of about thirty-
five met in Mr. Hudleston's Museum at 3 p.m. They much
regretted to find that their host was unable to be present to
receive them personally. He had, however, made all arrange-
ments by which the members might be enabled to see his
collection at their pleasure.

Mr. Blake mentioned the departments in which the collection

was especially rich, and then asked Mr. Semmons, who happened

to be present, to demonstrate the minerals, which he kindly did,

pointing out that the collection contained a number of specially

fine examples of Cornish minerals obtained while the mines were

in work, but now no longer to be had. After a short time spent

on these, the drawers containing the materials for Mr. Hudleston's

monograph on the Inferior Oolite Gasteropoda were brought out

^ne by one and replaced, the points of interest in each being

cfemonstrated by Mr. Blake and Mr. Newton as the drawers

j^assed round. In this way the Members were able to appreciate

rile great bulk of the material on which that work was founded, a

large proportion having been collected by Mr. Blomfield, who

mras present to show the collection. The specimens from the

Oreat Oolite and a series of estuarine forms from a new locality

w^re in a similar way examined.

Afterwards the company gradually transferred themselves from
th^ Museum to the drawing-room, where, after acceptable refresh-
ni^«it, a vote of thanks, proposed by Mr. Newton, was heartily
acc^orded to Mr. and Mrs. Hudleston for their kindness, and to
^^<^i^ Blake and Mr. Semmons for their interesting demonstration.

^^CXJRSION TO SEATON, SIDMOUTH, BUDLEIGH
SALTERTON, AND EXETER.

Easter, 1899.

-ZDireciors : Horace B. Woodward, F.R.S., F.G.S., and
W. A. E. UssHER, F.G.S.

Excursion Secretary: Bbdfokij McNkill, A.R.S.M., A.M.I.C.E., F.G.S.
iRe^rthyliw. Dikfxtors.)
I.— SF.AtON.
rw By H. B. Woodwaru.

iJ^^Nrv'-EiGHT years ago. Prof. James Buckman and Mr. J.
^^S^in Lobley conducted an excursion of the Geologists' Associa
^^ to the Yeovil district, and spent a short time on their fourth
July, 1899.] 11

134 EXCURSION TO SEATON, SIDMOUTH,

and last day along the cliffs east of Seaton.* It seems strange,
however, that forty years should have elapsed since the founda-
tion of this Association before any expedition was made to the
South Devon coast between Seaton and Exmouth, with its fringes
of Blackdown Beds and its famous pebble-bed of Budleigh
Salterton.

In 1889 an excursion was made to Lyme Regis, under the
guidance of the present Director, and the members then advanced
as far as the eastern portion of the Great Landslip.t It was now
planned to continue the exploration from the landslip westwards
to the mouth of the Exe.

On Thursday evening, March 30th, the members of the party,
which numbered nearly forty, arrived at the Royal Clarence
Hotel, Seaton. On Friday^ March ;^isfj the members started at
9 a.m. along the esplanade to Axmouth Bridge, where the
Director pointed out that the trend of the beach turned the
outlet of the river eastwards, and had been the means of choking
the harbour of the once flourishing little fishing-town. At the
close of the last century, a large tract of salt marshes extended
above Axmouth, but these had been drained to the advantage of
the neighbourhood. In far earlier times, when the river was
more potent in action, spreads of valley-gravel were laid down,
and from these at Broom, in the parish of Hawkchurch, above
Axminster, some fine palaeolithic implements, fashioned from
Upper Greensand chert, had been obtained. Remains of
Mammoth had been found in the Sid Valley, further west.

The party now proceeded by Squire's Lane to the lime-kiln
beyond the Coastguard Station, where the Middle Chalk, zone of
Rhynchonella aivieri, had been noted by Mr. A. J. Jukes-Browne.
This division cropped out along the 300 ft. contour-line. Several
specimens of Jnoceramus mytiloides and poor examples of the
characteristic Rhynchonella were obtained.

Passing on through Barn Close and Stony Close Lanes, a
pleasant walk over the grassy Chalk-plateau, here, in places
400 ft. high, led to the western end of the Great landslip at the
Bindon Cliffs. The view eastwards through the chasm was grand
and striking, the slipped masses of Chalk and Greensand forming
a platform about 100 ft. lower than the cliffs from which they
had broken away. As some account of this Great Landslip,
which happened at Christmas, 1839, has already been published
by the Association, J no particular description need now be
given.

Leaving the chasm, the members proceeded a short distance
westwards along the brow of the cliffs and descended by a foot-
path to the shore a little west of Culverhole Point. Here in the

• Froc. GeoL Assoc.^ vol. ii, p. 250.
t IHd.^ vol. xi, p. xxyi.
X Ibid.y vol. xi, p. xliii.

BUDL£IOH SALTERTON, AND EXETER.

»35

low cliSs fringing the beach a tine section of the Rh;etic Beds
was exposed. On the west side, and indeed from the mouth of
the Axe eastwards to near Cuiverhole, the high clififs are formed
of Chalk and Greensand, resting on a foundation of the red and
▼ariegated Reaper Maris. These marls are bent into gentle
ondulationSy and they are displaced by several faults which cut
the cliffe obliquely and sometimes nearly parallel with the coast
Near Seaton and Branscombe they contain gypsum and pseudo-
morphous crystals of rock-salt. Towards the top of the red
maris there is a layer of hard pale-grey or bufif banded marl with
dark clayey streaks, which marks the commencement of the
gradual change of conditions into the succeeding Rh;etic series.

The strata dip eastwards at an angle of about 5 deg., and within
a short distance the entire Rhsetic series is exposed. These beds
again are displaced by slight faults, some of which, however,
appear to be due to landslipping. Resting on the White Lias, as
hkd been observed by Mr. Jukes-Browne, there were some pale-
grey clays belonging to the base of the (lault, and it is interesting
to note that Conybeare had in 1S40 referred to a possible trace of
Gault near CulvCThole. *

The section at Culverhole was as follows :

Rh.ctic .
Beds ]

White Lias

I Black
^ Shales
Tea-green marls
( passage- BEns

FROM RH-tTlCINTO

Keuper).

/ Thin-bedded white limestones, here and
! there wed sje- bedded, and with concrc-
; tions or pebbles of comjuct limestone
'j in the lower part ... ... alvut

I Impcrsisient masses of rudely .irlvr-
\^ es<-ent Cotham Stone ... ... about

I Avidtiat'OHU^rta Shaies with K»ne-bevl

» 2t base aN>ut

» Green marl ...

I .Mternations of pale greenish and cieamy

f marls with hard hands of marly limc-
btone and dark grey and black clays ...
, Dark, light-grey, green, and red cuboidal
! marls

ft. in.

15 o

o «

IvS O

10 o

,. ! Hard layer of pale-grey or buff kmdcd
keuper ^ ^^^, ^.jjj^ j^^^ ^,|.^y^y streaks

I Green, gfc\\ and red marls
LRcd and variegated marls

The Tea-green marls form a persistent band on top of the red
and vari^ated marls, but with no definite plane of division
separating them. The change in colour from the mass of red
marls with their irregular mottling, to the mass of grey, green, and
almost black marls and clays, indicates a gradual change of sedi-
mentary conditions, and not a change due to subsequent chemical
action. The Red marls (as is well known) retain their distinctive
colour at the surface, while the Tea-green or Grey marls possess
the same colour at a depth below ground as proved in borings.

• " Memoir on LAiidslips,' p. 2.

136 EXCURSION TO SEATON, SIDMOUTH,

The hard bands in the red and grey marls may be sedimentary
limestones.*

At Axmouth the occurrence in the Tea-green marls of the
bands of dark grey or black clay foreshadow the Black Avicula-
contorta shales, but they do not in this locality appear to be
fossiliferous. A bone-bed has, however, been met with in the
green marls, 4 ft. below the Black Shales at (iold Cliff; and else-
where, as at Watchet, fossils have been rarely obtained at such
horizons. The occurrence also in Warwickshire of Acrodus
keuperinus, A. S. Woodw., and Simionotus brodiei^ Newt.,t as
well as of Goniomya and other lamellibranchs,;^ is significant that
conditions suitable to life came on somewhat irregularly during
the Triassic period in the British area. Hence it is that this Tea-
green marl series, which was grouped with the Rhaetic Beds by
Messrs. H. W. Bristow and R. Etheridge, is in some localities
more closely allied with the Rhaetic Beds, and in other localities
with the Keuper Marls.§ As Edward Forbes pointed out, the
Red marls were probably formed in a great inland sea, like the
Aralo-Caspian, during the later stages in whose history there were
influxes of the sea, bringing in the Rhaetic fauna, while the
Liassic fauna overspread the area during subsequent depression.

The Axmouth Bonebed lies at and near the base of the Black
Shales. The rib of a Reptile was observed by Mr. E. T. Newton
near the base of the Shales, while numerous Fish-remains, includ-
ing Acrodus^ Gyrokpis alberti^ Ag., Hybodus^ LepidotuSy and
Sargodon ? were identified by him from specimens obtained in
crevices of the Green Marl at the base of the Black Shales. ||

Numerous fosiils were found in the Black Shales, including
the characteristic Avicula contorta^ Port!., also Anatina praairsor^
Quenst., Cardium rhcetiaan^ Mer., HinniteSy Modiola^ PtcUn
valoniensisy Defr., and Pleurophnrus.

Leaving Culverhole, the party retraced their steps along the
footpath to the top of the cliffs, and proceeded westward along
Haven Cliff (300 ft.) to the old quarry south-east of the Coast-
guard Station, where the junction of the Upper Greensand with
the Lower Chalk was exposed. The junction was by no means
well defined, but the basement portion of the Chalk, or so-called
Chloritic Marl, which contains quartz grains and grains of glau-
conite, and rests on brown sandstones (Upper Greensand), yielded
the following fossils, which were identified by Mr. E. T. Newton:^

* See H. B. W., " Memoir on Lias of Engl.iml and Wales" (Geol. Survey), p. 31.

fK. T. Newlon, Quart.Joum. Geot, Soc , vol. xliii, p. 537.

X R. B. Newton, Geol. Mas[.^ 1893, p. 557.

§ See H. H. W., Proc. Geol. Assoc., vol. x, p. 539.

II See also Egerton, Proc. Geol. Soc.^ vol. tii, p. 409.

% Stn also Meyer, Quart. Joum. Geol. Soc., vol. xxx, p. 393; Barrois, " Recherches
sur le Terrain critacc," 1876, p. 75; Jukes-Browne, Geol, Mag., 1877, p. 361 ; Meyer and
Jukes- Browne, Ibid., 1894, p. 494.

BritLElGH >ALTERTOX, AXD EXETZR-

137

*• =r ^ 7 r >»

2t_

£lf

P3"
5'X

4
S

•^1

1 =

2 S 2 5 Iq 1» Vqx

lil Li ill M

N i

-;^

M 2

138 EXCURSION TO SEATON, SIDMOUTH,

Ammomtes {Acanthoceras) manielli^ Sow. ; Am, (A.)
navicular is, Mant. ; Atfi, (A,) rotomagensiSy Brong. ; Nautilus^
sp., Pleuroiojnaria ? (cast), Exogyra^ sp., Lima hoperi^ Sow. ;
Pecten asper, Lam. ; Pecten (Neithea) quinquecostatus^ Sow. ;
Rhynchonella dimidiata, Sow. ; and Discoidea subuculuSy Leske.

Returning to Seaton, the members (after lunch) proceeded
along the West Walk by cliffs of Red (Keuper) Marl to the foot
of White Cliff. Here the cliffs, which rise 10 a height of about
250 ft., show a grand section of Chalk and Upper Greensand,
resting on the Red Marl. Owing to a syncline, the Lower and
also the Middle Chalk descend westward to the sea-level, and
rise again beyond Beer Head. At White Cliff the beds are
faulted against the Red Marls on the east, a fault not clearly
shown in section owing to the talus, but proved by the flat
bedding of the marls in the cliffs and on the foreshore east of the
fault, whereas the Cretaceous beds on the west are tilted up. The
Greensand is here conspicuously divided into an upper cherty
series, and a lower series of greensands which yield many of the
fossils of the Blackdown Beds (zone of Ammonites rostratus).
At the very base of the Greensand (as observed by Mr. Jukes-
Browne) there are greenish clayey beds which belong to the zone
of Ammonites lautus. The chert-beds, as observed by Mr.
Meyer, yield Pecten {Neithea) quadricostatus^ Exogyra columba^
etc., and they are separated from the Chalk above by 20 ft. or
more of buff-coloured and glauconitic sandstone.

It was pointed out that the Chalk of this region was broadly
divided as follows :

( zone of Micrasters
) ,, „ Holaster planus
J[ „ „ Terehraiulina gracilis
I ,, „ Rhynchonella cuvieri

Lower Chalk including Chloritic Marl.

Upper Chalk
Middle Chalk

Information kindly furnished by Mr. A. J. Jukes-Browne
enabled the members to readily see the successive zones which
have been identified in the Chalk from the summit of White
Cliff to the shore at Beer. Ascending White Cliff by the foot-
path near the fault, and passing over the higher part of the hill,
the members descended to a bluff known as Annis Knob. Here
a mass of remarkably nodular chalk was seen, the nodules being
some of flint with thick white siliceous crust and a tiny nucleus
of black flint, while a large number were composed of more or
less siliceous chalk.

A prominent band of black flints near the middle of the
bluff was taken by Mr. Jukes-Browne as a convenient divisional
plane between the zones of Micraster cortestudinarium and
Holaster planus. Not many fossils were found in the exposed
face of Chalk, but it was understood that Dr. A. W. Rowe
and Mr. C. D. Sherl>om had not long previously made an

BUDLEIGH SALTERTON, AND EXETER. 1 39

exhaustive search. The Micraster beds above the prominent
flint-band yielded Tertbratula carnea. Sow., Terebratulina
stricjta, Wahl., Rhynchonella reedensis}^ Eth., and a plate of
CidaHs, From the zone of Holaster planus^ in which thin layers
of hard compact chalk (Chalk Rock) were noticeable, there were
obtained the characteristic Holaster, also Micraster breviporus^
^yp^u>5oma^ and Terebratula camea. These and other fossils
^ere identified by Mr. Newton. Descending to the main portion
of the cliff which forms the eastern side of Beer Harbour, it
^s pointed out, on the evidence of Mr. Jukes-Browne, that the
v-hallc which forms the upper part of this cliff bordering the
Roping pathway that leads to the beach, belonged to the Middle
^ballc zone of Terebratulina gracilis^ ab(DUt 80 ft. thick, beneath
which, and bordering the shingle beach was the zone of Rhyn-
^^nc/ia cuvieriy about 40 ft. thick. Many small specimens of
^'^^^ratulina gracilis^ Schl., var. lata^ Eth., were obtained from
ihe 2one of T. gracilis. The lower beds belonging to the zone
^^ -^. cuvieri, including the representative of the Beer Stone,
<J?Tnod the headland with a natural archway on the eastern side
?^ Reer Harbour; while reefs of the Lower Chalk extended
?^nea.th and formed the point, resting on a floor of the Upper
, ""^^nsand, which gradually rose eastwards under White Cliff.
^•"^s mentioned that a manufacture of gun-flints was formerly
^^ied on at Beer Head.

^eer Village (which takes its name from the Norse byr^

^gnifying an abode or farmstead) rests on an inlier of Upper

'"^^tisand. After taking tea in the village, the members proceeded

^'^S Quarry Lane to the famous Beer Stone quarries, about a

"^**^ distant. On the north side of the lane there is an immense

^^^^ry, about 80 ft. in depth, in the Middle Chalk, with tunnels

. ^^e base, where the Beer Stone has been more recently worked,

^ Upper strata having been quarried for lime-burning. These

'^ prise the zones of Terebratulina gracilis and Rhynchonella

^ ^*^^* On the south side of the lane the stone had been

i^^ted underground from a very early period. The levels have

^*^ driven in nearly along the 300 ft. contour.
Yy T'he Managing Director of the Beer Freestone Co., Mr. A.
^ • Oakley, had most courteously arranged that both new and old
J- ^^^ings, which extend long distances underground, should be
^^■^^^d with candles, and the members were conducted through

^ ^xiany and devious ways by Mr. E. Terrell.

Y^ 'X'he tunnels are supported by masses of the freestone, aided

^* '"^ and there by timber. The stone is sawn out in situ, and

^^^Vs from six to eight tons are obtained. It is comparatively

p^ when taken from the workings, but hardens on exposure.

^^^ti its uniform texture and close grain it is admirably

^^pted for carving, and especially for inside decorative work.

• Jukes-Browne, Quart. Joum. Geoi, Soc., vol. liv, p. 24-,^.

14© EXCURSION TO SEATON, SIDMOUTH,

It has, however, been used with success for outside work in
many of the neighl)Ounng churches, and it is now being
employed in the building of the Roman Catholic Cathedral at
Norwich.

The rarity of fossils, of course, has been an advantage to the
Beer Stone. Mr. Terrell exhibited a few specimens which he
had obtained from it, and they included Nautilus, Inoceramus
mytiloideSy Mant., Terebratula setniglobosa. Sow., Echinoconus
subrotunduSy Mant., and Lamna appendiculata, Ag.

Fitton many years ago thought that the Beer Stone might
represent the Totternhoe Stone,* but it is now known to be on a
higher horizon.

After a hearty vote of thanks to Mr. Oakley and Mr. Terrell
the party were driven back to Seaton.

II.— SIDMOUTH.
By H. B. Woodward and W. A. E. Ussher.

April 1st. — Leaving Seaton soon after 9 a.m., the members
were driven along the new Beer road and across the plateau of
Chalk and Upper Greensand, by Stovar Long Lane to Holy Head
y4i9 ft), and past Hangman's Stone (479 ft.), to the top of
SalcombeHill(557ft.). Here, alighting from the vehicles, they took
the track leading by South Down Farm towards the brow of the cliffs.
Attention was arrested by some large blocks of siliceous breccia,
and these were presumed to be relics of former Eocene deposits
which once spread across the area, and to which further reference
was subsequently made (seep. 151). Long ago Mr. Godwin-
Austen remarked on the resemblance of these blocks to grey-
wethers,t and it was mentioned that rolled portions of the rock
picked up on Sidmouth beach have been polished and sold as
Sidmouth pebbles. The included fragments were angular, but, as
Mr. Clement Reid had shown, the materials forming the Bagshot
gravels were more and more angular as they were traced west-
wards.

It was not possible, owing to the mist, to see the stretch of
coast-line east of Sidmouth, but it was remarked that there was
evidence of two great plains of erosion (or peneplains), the one
formed by the denudation of the Oolites, Lias, and New Red series,
on a fairly level surface of which were laid down the Upper
Cretaceous strata ; and the other by the denudation of the Gault,
Upper Greensand, and Chalk, on which were remnants of Eocene
(Bagshot) strata, more or less modified or re-arranged in places
by subsequent subaerial agencies. Reference was also made to

* Trans Ctol. Soc , ser. 2, vol. iv, p. 234.
t Ibid.^ scr. 2. vol. vi, p. 447.

BUDLEIGH SALTERTON, AND EXETER. I4I

Buckland's early observations on the formation of valleys in this
district* The President (Mr. Teall) referred to the contrast
between the two earlier unconformities which formed such a marked
feature in the geology of the West of England. The " continental "
New Red Sandstone formation rested on an uneven land-surface
composed of folded Culm and other rocks ; the marine Upper
Cretaceous rested on a flat plain of denudation. These two
uncomformities forcibly reminded him of the two much older
unconformities of the North-West of Scotland, where the ** con-
tinental " Torridonian rested also on a surface which had been
ciarved into hill and valley, and the maiine Cambrian on what
^vas once a flat plain.

On nearing the brow of the clifls on Salcombe Hill the
nembers were met by Mr. Ussher, who now undertook the
^direction.

Mr. Ussher said they were about to visit only a small part of
tLhe finest and most continuous New Red Sandstone seciion in
£ngland, if not in the world — one which should be taken as
^he basis for classification. He deprecated any classification
founded only on the coast section, magnificent as it was.
Xn that section the Lower sands and breccias came on
^^rhh a fault at Exmouth, and the contemporaneous traps (a
probable correlative of the Permian melaphyres of Germany) were
not represented. The general downward succession was : Upper
^ed Marls, Upper Red Sandstone, Pebble-beds, Lower Red
^arls and Marls with Sandstone, Lower Sandstone and Breccia,
Xreccia and Conglomerate, Watcombe Clay. They would not
see anything below the upper part of the Lower Sandstone and
Xreccia on the coast towards Exmouth.

Descending by the zig-zag path to a foot-bridge over the Sid
^t Sidmouth, the members walked a short distance eastwards
<^long the shingle, the outlet of the river being at the time entirely
^:hoked by the beach.

Mr. Ussher showed the conformable nature of the junction
^jetween the Keuper Marls and underlying sandstones, scarcely
disturbed by three small faults. In the occurrence of occasional
^^hin flaggy beds of sand- and mud-stone in the lower part of the
IMarls, the equivalent of the Waterstones of the Midlands was
^^ecognised.

The President thought that the red colour of the formation

"^as mainly due to the subaerial decomposition of rocks contain-

:ing ferriferous compounds, under conditions similar to those

;3)revailing at the present day in India, the Southern States of

"^astern North America, Brazil, and parts of Africa, in short, to

"what might be termed the lateritic type of decomposition. Under

^his mode of decomposition the iron becomes oxidized, and

<ieposited as a coating on the grains of quartz and other un-

• Tratu. Geo/. Soc , scr. a, vol. i, p. 94.

142 EXCURSION TO SEATON, SIDMOUTH,

decomposed minerals. The red material thus produced would
mantle the slopes, fill up the hollows, or be spread out as flat fans
over the low ground by torrential action. It would also be
deposited in lakes, lagoons, or seas. In the presence of decom-
posing organic matter the ferric oxide would be reduced, the red
colour would disappear, and the iron would take the form of a
sulphide or carbonate. Thus the change in the colour seen near
Axmouth at the junction of the Rhaetic and Keuper was directly
connected with the absence of fossils from the latter and their
abundance in the former deposit.

After visiting Sidmouth, the members assembled at the
Chit Rock at the western end of the Esplanade, and then pro-
ceeded by the road and footpath west of Sea View, and descended
by the wooden staircase to the beach on that side of the Chit
Rock. Here a composite fault wac seen cutting off the sandstones,
and throwing down the marls on the west.

From this point the cliffs rapidly rise westwards from about
50 ft. to 500 ft. at Peak Hill, where there is a capping of Upper
Greensand and gravel, while inland the ground rises over 600 ft.

Farther on Mr. Ussher called attention to the outcrop of the
sandstones on the beach, and below Windygate he showed that
the junction was not a definite plane, inasmuch as the lowest
beds of the marls are more or less sandy, and pass imperceptibly
into sandstone, so that viewed from the beach the junction-line,
without any apparent change, seemed higher up the cliff in some
places than in others. On the beach he pointed out a calcareous
concretionary bed denoting the outcrop of the upper part of the
conglomeratic beds in which, at Otterton Point, Mr. H. Johnston-
Lavis found Labyrinthodon^ and the late Dr. H. J. Carter many
traces of bones.* Mr. Ussher showed that the concretionary
character was not restricted to an absolute horizon.

Mr. Newton here illustrated some remarks by the exhibition
of a jaw of Hyperodapedon^ a lacertillan reptile which had been
obtained thirty years ago by Mr. Whitaker, and was the first fossil
(of the period) found in the New Red rocks of this region.

The grand cliffs of Red Marl below Peak Hill attracted
attention, the deep rain-channels cut in the marls giving to the
scene a canon-like appearance.

Ascending by a trackway to the Windygate path (350 ft.) west
of Peak Hill, the members observed traces of pseudomorphs of
rock-salt in the green, shaly sandstone. After a halt for lunch,
they proceeded along the brow of the cliffs to Ladram Bay. The
cliffs, which are here about 50 ft. high, were seen to consist of
Red Marls on Sandstones, faulted in several places, and worn
away into picturesque bays with a prominent stack known as the
Hern Rock.

Ladram Bay, which contains a natural arch on the north

* Quart. Joum. GeoL Sac., vol. xliv, p. 318.

BUDLEIGH SALTERTON, AND EXETER. 1 43

side, was then visited. Mr. Ussher here drew attention to the
false-bedded character of the sandstone, and to the local occur-
rence of a network of calcareous concretions, best seen between
Ladram Bay and Budleigh Salterton. This was suggestive of the
Lower Keuper Dolomit of Germany.

The party then proceeded through a deeply-cut lane in the
Red Sandstone, towards Otterton, visiting a brick pit in an outlier
of Keuper Marls, which Mr. Usshei showed by the maps to owe
its position to the repeating faults on the north side of I^dram
Bay.

After passing through the pleasant village of Otterton, and
crrossing the river Otter, which was bordered in places by red
sandstone cliffs, the Members reached East Budleigh Station, and
t^ook train to Exeter, for the Rougemont Hotel.

in.— BLACKDOWN.
By H. B. Woodward.

April ind. — After breakfast a small party left the Great
AVestem Railway Station (St. David's), lor CuUompton Station,
^nd then walked by Kentisbere Moor, Kentisbere, Moneyland,
^:xn^ France to the Puncheydown or Poncheydown Inn on Black-
tiown, here about 750 ft. above sea-level. A few fossil sponges
^and some echinoderms and other fossils were purchased at the
Bnn.

Afterwards a whetstone level, N.E. of the post office on
IBlackborough Common, the only working now open, was visited.
The stone used for the manufacture of the scythe-stones, whet-
stones, or Devonshire " Batts," occurs irregularly in the greenish
sands, the good stone being sharply jointed and occurring in
^rger and smaller masses together with a few irregular and
fantastically formed nodules of cherty sandstone.

The stone is soft when taken from the workings, and it can
^hen be readily shaped and afterwards rubbed down (with water)
into proper form. On drying it becomes very hard. Fitton, who
^ave an excellent account of the strata, remarked that formerly
9 large proportion of the scythe- stones used in England were
obtained at Blackdown.* Even now there is a demand greater
than the very limited supply which can be obtained from one
working, but the useful beds are said to be nearly exhausted.
They occur from 15 to 25 ft. below the surface, and have been
worked along the steep scarp of the hills. The whetstone-beds
cccur beneath a head of cherty detritus, and the beds themselves
are about 25 ft. thick, resting on 20 or 30 ft. of yellow sand-
rock.

• Trans, Geo!, Sik., ser. a, vol. iv, p. 234.

144 EXCURSION TO SEATON, SIDMOUTH,

The whetstone rock as described by Dr. Hinde "is filled with
sponge- spicules and their empty casts, cemented together by
chalcedonic silica. Quartz-sand and glauconite grains are also
present, but no calcite, and only a small amount of mica. . . .
The spicules are chiefly of chalcedonic silica ; some appear to be
partly of crystalline silica; ... the cementing silica, which
renders this material suitable for whetstones, is derived from the
solution of the spicules, and the chalcedonic silica, which has
replaced the calcite of the molluscan shells in the same beds, may
be attributed to the same source.*

To the Rev. W. Downes we have been indebted for our latest
information about the Blackdown Beds and their fossils.f He
pointed out that " a good deal of confusion has arisen through
the mingling together in collections of specimens from other
Greensand localities with Blackdown fossils," and he observed
that " No true Blackdown fossil is calcareous."

At Salcombe Hill and some other localities similar silicified
fossils are to be found.

Among the more abundant of the Blackdown fossils are :
Siphonia tiilipa{S,pyriformis^Cio\di,\ Vermicularia concava, Sow,
Rhynchontlla^ Exogyra conica^ Sow., Gervillia ancepSy Desh.,
CucuUcea carinata^ Sow., Pecten mi Her i, Sow., Pectunculus
ufiibonatuSy Sow., Trigonia scabricola^ Lye, Cyprina angulata^
Flem., Aporrhais parkinsoni^ Mant, Dimorphosoftia calcnratay
Sow., Turriiella granulata^ Sow., and Ammonites varicosusy
Sow. Examples of many of these were obtained.

The Blackdown Beds were regarded by Godwin- Austen and
Daniel Sharpe as representing a more or less littoral facies of the
Gault ;J and it is now known that they represent the Upper
Gault, zone of Ammonites rostratus.

Proceeding to the highest point of Blackdown, 897 feet, the
members had a good view of the Wellington Monument, and
they then returned by Poncheydown gravel pit and Newcombe
Common to the lane, by Saint Hill and Hollis (Jreen. Passing
through Kentisbere, and noting a section of the Pebble- beds
on the horizon of those of Budleigh Salterton, they proceeded
to Cullompton Station by Kentis Ford and Long Moor, taking
a peep at the rough, cherty gravel which here and there overlies
the Lower Red Marls in this area. It was mentioned that
the Rev. W. Downes had obtained a Palaeolithic implement
from the gravel on Kentisbere Moor, near Kentisbere, § where
for several years he resided as curate. This enthusiastic worker
afterwards became Rector of Combe Raleigh, near Honiton, and
died in 1886.

* Phii. Trans., 1885, P- 4ai.

t Trans. Dei»on Assoc., vol. xii, 1880, p. 420, and Quart. Journ. Ctol. Sec., vol. Yxxviii,
P- 75.

t Qt$att. Joum. Geol. Soc., vol. vi, p. 47a ; vol. x, p. i85.
§ G€oL Mag.^ 1870, p. 480.

BUDLEIGH SALTERTON, AND EXETER.
IV.— BUDLEIGH SALTERTON AND EXMOUTH.

145

By W. A. E. UssHER.

April jrd, — The members started from the Queen Street
Station, Exeter, by the 9 a.m. train to Exmouth, where vehicles
awaited them, and they were driven through a pleasant hilly
country to the Rolle Arms Hotel, Budleigh Salterton. On
the way a pit in the Triassic Pebble-beds was passed.

On leaving the hotel the attention of the party was called to
the view of Otterton Point and Budleigh Salterton Parade. At
Otterton Point the conglomeratic beds in the Upper Sandstone,
the outcrop of which had been seen in Lad ram Bay, occupy the
base of the cliff for about 10 ft. ; the cliff by the Budleigh
Salterton Parade is formed of sandstones underlying the con-
glomeratic beds in which the irregular calcareous character is well
shown. The Director showed the impossibility of making any

KiG. 2. — The Cliff West of Budleigh Salterton, Devonshire.
(W. ViCARY, Quari. 3^ourn. Geol. Sac., vol. xx, p. 283.)

d. Gravel.

c. Red sandstone. (Keuper | h. Pcbblc-beJ. [Bunler.]

a. Lower red marU ('* Permian. ']

^^'.B. — The grouping given in brackets in Figs, i and 2 is that adopted on
the Index Map of the Geological Survey.

division, even an arbitrary one, in the sandstones ; and having
j)reviously shown their intimate relation to the overlying marls,
lie claimed them as Lower Keuper.

The cliffs rise rapidly from about 30 ft. at the " Rolle Arms"^
to over 400 ft. at West Down Beacon, the scarp of the Pebble-
beds. For a short distance the sandstones were seen to be
covered with a thick bed of pebble-gravel, a downwash from the
higher exposed outcrop of the Budleigh pebble-bed. (See
Fig. 2.)

The pebble-beds which crop out on the beach from under the
sandstones at a short distance from the commencement of the

146 EXCURSION TO SEATON, SIDMOUTH,

cliff are about 70 ft. thick ; three small faults occur in them.
Their relations to the overlying sandstones are perfectly con-
formable, and lenticles and beds of sandstone occur in them,
rendering it very difficult, in the local failure of pebbles, to
distinguish the one horizon from the other. Although the
Director had often noticed that the sand replacing Pebble-beds
contained rounded grains, whilst the overlying sands were more
or less angular and finer, sufficient observations had not been
made to establish a general rule. In the sandstones, pebbles
occasionally occurred at some distance above the pebble-beds, an
instance of which was afforded at the commencement of the cliff.
In this intimate connection, and in tracing the horizons north-
ward throughout their extension, the Director could not see his
way to classify these beds with the Bunter; and as he considered
that the sandstones were not older than Lower Keuper, he
regarded the pebble-bed (which passes into a hard conglomerate
with calcareous cement in the Wellington and West Somerset
area) as the base of the Keuper. The pebble-beds rest on about
500 ft. of marls of similar, character to the Keuper Marl, and
mottled with small greenish spots. The junction which, in con-
sequence of slip, was not well exposed on the beach, had
furnished him with no proof of unconformity, either as regards
dip or erosion. The very trivial irregularities in the exact line of
junction were such as he had often observed in the New Red
rocks (for instance, in the Lower New Red Sand and Breccia cliffs
bounding Oddicombe beach), and appeared to be slight signs of
contemporaneous erosion. (See remarks by Mr. Clayden, p. 148.)
He, however, regarded the base of the pebble-beds as an impor-
tant evidence of physical change, such as might be occasioned by
the destruction of a barrier between deposits forming under
lacustrine conditions and the then existing coast, whereby pebbles
would be swept northward over lacustrine marls. Mr. Ussher
stated that the Devonian and Silurian quartzite pebbles so
abundant on the coast were more or less gradually replaced by
pebbles of more local origin, as the bed was traced northward
beyond Uffculm.

Mr. Newton here made some remarks on the fossils found in
the pebbles, which had been submitted by Mr. Vicary to the late
Mr. Davidson for identification. From specimens collected,
Mr. Newton identified Orthis budieighensis^ Dav., Lingula
ksueuriy Rou., and worm-burrows {Trachyderma}),

Mr. Woodward remarked on the fact that similar quartzites
occurred in the Bunter pebble- beds of the Midland counties.
Prof. Lapworth, who had so lately given an account of these, had
pointed out that there might be quartzites of pre-Cambrian,
Cambrian, Ordovician, Silurian, Devonian, and Carboniferous
ages.* There were at any rate Ordovician pebbles with Orthis

• Proc. Geol. Assoc.^ vol. xv, p. 382.

bcdljeigh s.\lterton, and exetek. 147

htd/ei^kemsisy and also Lingula lesuisuri (of the Gres
Armonom) ; and Devonian pebbles with Spirifir vemeuili and
/fMia£mifias^ Whedier these Midland pebbles were accumulated
in areas whofly marine, or wholly fluviatile ; whether they were
den¥^ in part from earlier conglomerates, or were entirely shaped
in Triassic tmies : whether they came from the north or south, or
from local rocks,, were questions put (but not answered) by Proh
Lapworth : and they might be put at Budleigh Salterton.

The President pointed out that not only were fossils of the
Hodle^h Salterton pebbles found in the £unter pebbles of the
Xlidland counties^ bat that pebbles of schorl>rock, similar to those
so aboxxiant on the beach before them, were also found in the
hunter of Xottinghamshire. He had recently examined two
(Pebbles collected by Mr. H. W. Monckton from the;Bunter of
Nottinghamshire^ and they were practically identical with contact-
shocks occurring in the West of England. It should be remem-
Ir^ered that the so-called schorl-rock included altered granites>
^v^in-stoff^ and metamorphosed shales, impure cherts and
Krits.

On the way to Straight Point, the occurrence of a bed or beds
c^ sandstone in the marl in one spot was observed. At 1 .ittleham
0>ve, near Straight Point, the Director showed that the marls
^^cere cut off by a fault (downthrow about 150 ft. to north \ against
Knarls on sandstone and sand, false laminated, and p>artly brecciated
^vrith nearly angular hard, dark quartzite stones. The sand grains
^ue often coarse and well-rounded, characters both as regards
iDrecciation, false lamination, and rounded grain, commonly met
^^rith in the sandstones and breccias of I^ngstone Point, !>awlish,
^tc- He was uncertain whether to refer the Straight Point
^^ndstones to the upper part of this Lower series, or to a (lassage
^^eries in the lower part of the Marls. He had not visited the
^^ection for many years, and the lower part was not then so well
exposed as on the present occasion. From what he saw before
^im, he should have no hesitation in considering the Straight
X^oint sandstones as the upper part of the series, cut out by a
^ault in Exmouth Shrubbery. Calcareous concretionary beds
^apparently dolomitic). were observed in the Straight Point
^sandstones.

On the other side of Straight Point, proceeding to Exmouth,

^^bout two miles distant, the way lay along a pleasant ex^xinse of

^^sands, with reefs of sandstone. The I)irector pointed out numerous

^Vaults affecting marls with thick beds of sandstone which he had

^^sapped over twenty years ago, and which had then seemed to him

'^o have the effect of placing the Straight Point sandstones at least

^8oo ft. above the base of the marls ; that appearance was con-

^rmed by the present inspection, and he begged leave to recall

"^he remarks he had made at the fault on the other side of the

^oint as to placing the Straight Point sandstones at the base of

148 EXCURSION TO SEATON, SIDMOUTH,

the marl series. The Director further remarked on the similarity
cf the sandstone beds in the marls to Bunter sandstones in
Germany, a similarity noticed by Baron von Reinach in 1891, on
a visit to this coast. After passing Orcombe and Rodney Points,
the members reached Exmouth, and visited the Shrubbery or Plan-
tation at Beacon Hill, where sandstones, brecciated with numerous
fragments of similar character to those at Straight Point, but
undoubtedly belonging to the Lower series^ are exposed, being
faulted against the marls with sandstones. This similarity showed
the intimate connections of the marl series below the pebble-beds
with the Lower series of sands and breccia.

From Exmouth the train was taken to Exeter.

After dinner voles of thanks were accorded to the Directors, and great
indebtedness was then expressed to two resident workers at Exeter, Mr.
Arthur \V. Clayden, F.G.S., and Mr. F. G. Collins, F.G.S., who had largely
added to the success of the excursion by their local knowledge. Regret was
expressed at the absence, through the infirmities of age, of Mr. William Vicary,
F.G.S., whose life-long labours on the geology of the country around Exeter
were so well-known and appreciated.

Mr. Clayden then very kindly exhibited a series of lantern- slides ; also
his interesting models of ocean currents, and explained what a tremendous
effect on the climate of the North Atlantic, and also on that of the South
Atlantic, would be produced by any considerable submergence of Central
America.

On exhibiting a photograph of the Budleigh Salterton pebble-bed, which
showed the coarse pebbles resting on the underlying marls, Mr. Clayden
remarked that this was the section referred to by Dr. Irving, and he now called
attention to the markedly irregular surface of the marl, which certainly
suggested erosion. When it had been remarked that the irregularity might
be caused by a small fault, he had pointed out that many of the lines of pebbles
were quite continuous across the section and showed no trace of faulting.

When showing some diagrams of the volcanic rocks of the Exeter
district, Mr. Clayden remarked that the breccias and other rocks which
accompanied and overlaid the lavas certainly seemed to have come from lofty
hills lying somewhere to the west or north-west, probably the former ; and it
was reasonable to suppose that the lavas might have come from the same
direction. Sir A. Geikie. in his great work on "Ancient Volcanoes of Britain,''
expresses the opinion that the vents are now buried under the New Red
series. This would imply a flow from the east or north-east. None of the
vents had yet been found. In the valley of the Teign, however, there were
a large number of pipes, sills, and bosses, of a basic or intermediate type,
many of them being intrusive into the contorted Culm-Measures, while the lava
at Pocombe lies on the denuded edges of the same rocks. They occur a few
miles west of the lavas, and it seemed worth while to inquire whether some of
them might not be the actual sources of the Exeter trap?. The lavas were
much decomposed.

The President expressed the opinion that the decomposition of the Exeter
traps was largely of New Red age, and that it represented what he had
termed the lateritic type of decomposition. The destruction of the igneous
rocks had contributed to the formation of the red beds.

A visit was now paid to the Devon and Exeter Albert Memoiial Museum,
under the courteous guidance of Mr. James Dallas, the curator. A brief in-
spection was made of the objects of natural history and art, and the members
were afterwards conducted through the fine Free Library and the Technical
and University Extension College.

BUDLEIGH SALTERTON, AND EXETER. 1 49

v.— EXETER, DUNXHIDEOCK, AND -GREAT HALDON.
By W. a. E. Ussher.

On Tuesday^ April 4th, the members drove from Exeter,

through St. Thomas*, to Crossmead, and were then conducted

along the road leading to Pocombe Bridge. Here a deep cutting

showed the junction of the trap with the Culm-measure shales and

grits, on the upturned edges of which it rests. The trap is

mingled with a film of earlier New Red sediment at its base,

doubtless caught up in the lava flow. In the Pocombe quarry,

west of Crossmead, the trap was overlain by New Red sands.

The thickness of the Pocombe trap is said by Mr. Vicary to be

from 30 to 70 ft.

The President referred to the important paper by Mr. B.
Hobson on the traps of the district. He himself was in doubt as
to the name that should be given to the Pocombe rock. The
felspar, to judge from the single specimen he had examined,
appeared to be an alkali-felspar containing much potash. If so,
the rock should not be called olivine-basalt. Olivinetrachyte
^'ould be more appropriate. Chemical analyses were absolutely
necessary to determine the petrographical af]6nities of the Exeter
traps, and the work would then not be easy, in consequence of
the extensive alteration which had in most cases destroyed the
ferro-magnesian constituents.

The party were then driven on to Ide (St. Ida*s), whence they
^^ralked to West Town, where there are three patches of trap.
VVest Town quarry, about a mile west of Ide, in the largest patch,
showed indurated sand-beds near the surface, which, Mr. Ussher
stated, were a common phenomenon, sometimes occurring in
I>ipes or dykes, the infillings of cooling cracks, by subsequent
Sedimentation ; sometimes as films, beds, or lenticles deposited
in the interval between lava flows, by which they were sub-
sequently indurated. These veins are occasionally dolomitic,
often light red in colour, and mottled with round greenish spots.
C^oUoquially Mr. Rutley and he used to refer to them as
*• Spottylite." Mr. Vicary had caused a pit to be sunk in the
floor of the quarry to the New Red breccia with trap fragments,
^^rbich Mr. Ussher inclined to regard as the earlier products of
Eruption mixed with the existing sediments. Mr. Teall pro-
nounced the rock a quartz-basalt ; he detected iddingsite in the
trap-rock.

Walking from Ide (130 ft.) uphill to Markham Cross (nearly
^00 ft), the members were then driven by Dunchideock Bridge
to the old quarry by the roadside at School Wood or Great
Plantation, and there it was observed that quartz inclusions were
less conspicuous in the trap-rock.

Proceeding \u the vehicles to Great Haldon, passing near to
July, 1899.] 12

15© EXCURSION TO SEATON, SIDMOUTH,

Belvedere (800 ft.), a glorious view was obtained of the Teign
Valley and Dartmoor. Mr. Ussher gave a brief address, pointing
out the eastern end of Dartmoor. He said they were looking
from a fragment of the great Tertiary planing of the Cretaceous
rocks, the eastern part of which they could see in the distant line
of the Blackdowns. The Greensands of Haldon were severed
from those of the Blackdowns by the excavation of the Exe
Valley and its tributaries. They had seen near Seaton ihe
Greensand resting on Rhaetic Beds ; at Salcombe and Peak and
High Peak Hills on Keuper Marls ; here, at Haldon, they found
it resting on the lower beds of the New Red Sandstone, showing
the overstep of the Cretaceous rocks. Between the New Red
fringe of Haldon Hill and Dartmoor the lower hills and dales
were composed of Culm-Measure shales and grits, with intrusive
artd perhaps contemporaneous masses of dolerite and some bands
of tuff. When they considered that these Culm rocks had been
compressed by the great post-Carboniferous movements into in-
numerable folds and contortions, and that subsequently they had
suffered such great denudation, prior to the deposition of the
New Red rocks, that the lower beds of that series rest on Lower
and Middle Devonian at Torquay and Paignton, postulating the
removal of the whole of the Upper Devonian and Culm rocks,
they would readily grasp the tremendous gap in time between
the Culm rocks and the New Red rocks, and understand why he
stood out for the term New Red Sandstone as applied to the
common character of the unbroken sedimentation in Devon of
the Secondary rocks below the Rhaetic Beds. There were slight
traces of a plane of denudation in the formation of the New Red
which may, to some extent, have determined the summits of the
Culm-Measure highlands. But here on Haldon there was beneath
them Greensand on the planed surface of the New Red
rocks, themselves unconformable on the Culm-Measures. In
conclusion, he would point out the thinning out of the
Dunchideock trap mass on the slope below Haldon, allow-
ing the overlying Breccia to rest directly on the Culm-
Measures. Further south, trap is visible in one place only,
near Whiteway House. There is no sign of it on the coast, and,
but that it seems nearly certain that the horizon occurs at the
base of the igneous boulder-bearing breccia of Teignmouth and
Labrador Inn, we should lack the most reliable fulcrum for classi-
fication in this maximum development of the New Red rocks of
the S.W. of England ; as, from correspondences in rock type and
in character of breccia, the correlation of the traps with the
melaphyr zone or Soterner of Germany, and of the overlying
breccia with the Wadern beds of the Upper Rothliegende, is by
no means improbable.

Driving past Haldon Gate (742 ft.), and near Buller's Hill
(827 ft.), to near the race course, the members alighted for lunch

BUDLEIGH SALTERTON, AND EXETER. 151

at a gravel pit (766 ft. above sea- level). Here Mr. Woodiirard
made some general remarks on the gravels which cap the Green-
sand, and which occur over a considerable area in the Teign
Valley, near Newton Abbot. When engaged in the re-survey of
that area in 1874 he was puzzled to account for the coarse gravels
which occupied the Bovey Basin, and seemed to be connected
with the platiiau gravels of Little and Great Haldon, portions of
which were then mapped by his colleague, Mr. Clement Reid.
The age of these doubtful superficial deposits, which he had
been disposed to regard as Drift,* had now been settled by
Mr. Reid, who, working steadily westward from the Isle of
Wight and Bournemouth, had noticed the incoming of various
rocks in addition to the customary flint-pebbles, and, moreover
iheir increasingly angular character. f The well-known gravel at
Blackdown Hill, near Portisham, was a noteworthy instance.
Mr. Reid now connected the coarse gravels on Haldon and near
Newton Abbot with the Bovey Beds, and he had called attention
to seams of white clay and rough quartz sand on Haldon. The
Bovey Beds, which comprise gravels and sands, white clays
and lignites, were regarded by Mr. J. Starkie Gardner
as of the same age as the Pipe-clays of Poole — Lower
BagshotJ The white clays and quartz sands in both regions
were presumably derived from the decay of granite in the
r^ions, ot which Dartmoor was a remnant, and it would be an
interesting task for Devonshire geologists to help in tracing out
the course of the old river which flowed in Eocene times from
Bovey Tracey and Haldon to what is now Poole — acioss a tract
of uplands which, however, has been considerably displaced here
and there by post-Eocene earth-movements. The greywethers
on Salcombe Hill, near Sidmouth, with their angular contents,
served in a striking way to support the views of Mr. Reid.

Attention was now directed to the Upper Greensand, and it
was remarked that the upper beds had yielded many Corals, such
as Placosmiliay Thamnastraa^ and Trochoseris^ which had been
recorded and described by Prof. M. Duncan. § Lower down
there were cherty beds, in which an example of Pecten elongatus ?
was obtained, while Holaster fossarius from Haldon was exhibited
by Mr. Woodward. Beneath these beds were greenish-grey sands
with indurated bands and fine conglomeratic layers, || the whole
resting on the New Red breccia.

Mr. Collins conducted the party to a gully north of the race
course and west of Woodlands Covert, where the junction of the
chert-beds and sanos was seen. In the harder beds of sand and

• Qitart.Joum. Geol. Soc.^ vol. xxxii, p. 230 ; Proc. Geol. Assoc., vol. xi, p. xlviii.
t Quart. Joum. Gioi. Soc.^ vol. Hi, p. 490, and liv, p. 234.
t Free. Gtol. AsstK., vol. vi, p. 100.
§ Quart. Joum. GeoL S0c., vol. xxxv, p 89.

I Apparenily a Mtnilar bed had been noied at Salcombe, near Sidmouth, by Godwin-
Austen, Trans. Geol. Soc., ser. 3, vol. vi, p. 449.

152 EXCURSION TO SEATON, SIDMOUTH, ETC.

glauconitic sandstone numerous fossils belonging to the Black-
down Beds were found, including Arca^ Cytherea plana^ Sow.,
Trigonia dadaUa, Park., and T, scabricola^ Lye. Specimens of
Cucullaa and Proiocardium hiilanum, Sow., were exhibited by
Mr. Collins.

The members were then driven by Kennford and Alphington
to Exeter, where, after dining at the Rougemont Hotel, most of
the members departed for their homes.

REFERENCES.

Geological Survey Map, Sheet 22 for coast from Seaton to Exeter ; Sheet 2 1
for Honiton (Blackdown Beds).

1870. Davidson, T. — "Notes on the Brachiopoda from the

Pebble-bed of Budleigh Salterton.** Quart. Joum, Gtol, Sac,, vol.

xxvi, p. 70.
1882. DOWNKS, Rev. W.— "The Zones of the Blackdown Beds." Quar/.

Joum. Geol. Soc., vol. xxxviii, p. 75. [Gives references to previous

literature, p. 76.]

1897. Geikie, Sir A.— "Ancient Volcanoes of Great Britain," vol. ii.

(Permian Volcanoes of England. Devonshire, pp. 94-ico).
1885. HlNDE, Dr. G. J. — " On B«ls of Sponge-remains in the Lower and

Upper Greensand of the South of England.*' Phii. Trans., 1885.

(Blackdown Hills, p. 421 ; Haldon Hills, p. 422.)
1892. HOUSON, B. — "On tne Basalts and Andesites of Devonshire known as

Felspathic Traps," Quart, Joum. Geol. Soc.^ vol. xlviii, p. 496.

1892. Hull, Prof. E.— "A Comparison of the Red Rocks of the South

Devon Coast with those of the Midland and Western Counties."
Quart, Joum, Geol, Soc., vol. xlviii, p. 60.
1888. Irving, Rev. A.—" The Red-Rock Series of the Devon Coast-section."
Quart, Joum. Geol, Soc, vol. xliv, p. 149. Supplementary Note,
/6td., vol. xlviii, p. 68, 1892.

1893. . — " The Base of the Keuper Formation in Devon.'' /5i</., vol.

xlix, p. 79.

1876. Lavis, H. J. Johnston. — " On the Triassic Strata ... in the

Cliff-sections near Sidmouth, and a note on the occurrence of . . .

the Bones of a Labyrinthodon." Quart. Joum. Geol, Soc., vol.

xxxi i, p. 274.
1874. Meyer, C. J. A. — " On the Cretaceous Rocks of Beer Head and the

adjacent Cliff-sections, and on the Relative Horizons therein of the

Warminster and Blackdown Fossiliferous Deposits." Quart, Joum,

Geol. Soc., vol. XXX, p. 369.
1861-64. Pengellv, W.— "The Red Sandstones and Conglomerates of

Devonshire," Parts I to HI. Trans, Plymouth Inst,, 1861-2, p. 15,

1862-3, p. 15, 1864-5, p. 15.

1898. Reid, C— "The Eocene Deposits of Devon." Quart, Joum, Geol.

Soc,, vol. liv, p. 234.
1898. Salter, A. E. — "Pebbly and other gravels in Southern England."

Proc, Geol. Assoc., vol. xv. QV'est Dorset and Devon, pp. 380-283.)
1876. USSHER, W. A. E. — " On the Triassic Rocks of Somerset and Devon."

Quart. Joum, Geol. Soc., vol. xxxii, p. 377.
1878. . — " On the Chronological Value of the Triassic Strata of

the South-western Counties." /*;</., vol. xxxiv, p. 459.

1892. . — " Permian in Devonshire." Geol. Mag,, p. 247.

1864. ViCARV, W.— " On the Pebble-bed of Budlcigh Salterton,** with a Note

on the Fossils by J. W. Salter. Quart. Joum, Geol. Soc,^ vol. xx,

p. 283.

CVCUNG EXCURSION FROM WINCHFIELD TO WOKINGHAM. 1 55

XS69. Whitacer. W.— '*On the Succession of Beds in the * New Red * on
the Soath Coast of Devon, and on the Locality of a New Specimen
of Hy0trgdmpedom:* Qmart, Jounu Gwi, Soc.^ vol. xxv, p. 152.

1M7- Woodward, H. B.— "Geology of England and Wales," Ed. 2.
fNew Red Rocks, p. 233 ; Cretaceous, pp. 391, 393 ; Superficial
deposits, p. 493.)

1890. Worth, R. N.— " The Igneous Constituents of the Triassic Breccias
and Conglomerates of South Devon." Quart, yourn. GtoL Soc^^
vol. xlvi, p. 69.

CYCLING EXCURSION FROM WINCHFIELD TO
WOKINGHAM.

Saturday, April 8th, 1899.
director: H. W. Monckton, F.L.S., F.G.S.

Excursim SecrtUry : W. P. D. Stebbing, F.C;.S.
{Revert by The Director.)

Leaving Winchfield a little before half past three, the party
cycled to the brick-field on the south-western side of Kazeley
Heath, 2f miles from the station.

The rather sandy clay worked belongs to the Middle Bagshot
Series ; the heath, in fact, is a Middle Bagshot outlier, and it is
capped by a gravel, the top being a flat expanse, with a level of a
little over 288 ft. above Ordnance Datum. The details are
clearly shown on Sheet 284 of the New Series Geological Survey
Map recently published.

There are numerous gravel-pits, one of which was selected for
examination. The gravel was seen to be fairly well stratified with
thin beds of sand here and there, the sandy parts frequently
showing current bedding. In some places the stratification was
less well marked, and often there was a certain amount of con-
tortion and patches of mottled gravel, but these seemed to be
always near the surface of the ground. In one section, 7 ft.
deep, the contorted part extended 5 ft. from the surface, whilst
close by a 10 ft. section showed no contortion. The gravel con-
sists mainly of sub-angular flints, whose brown colour suggests
long exposure to atmospheric agencies, and possibly they have
been derived from older drift. There is a good deal of cherty
material from the Hythe Beds of the Lower (ireensand, whose
nearest outcrop is now fifteen miles to the south-east. The
locality is on the western margin of the area over which this
Hythe Bed material has been distributed.* The Director gave
reasons for believing that this and all the gravels about were old

* See H. W. Monckton, Quart. Joum, Gtol, Sac., vol. xlviii, map on p. 38.

July, 1899.]

154 CYCLING EXCURSION FROM WINCHFIELD TO WOKINGHAM.

river gravels,* and no one present seemed inclined to dispute the
point.

Leaving Hazeley Heath the members crossed the little river
Hart and ascended Star Hill on to Hartford Bridge Flats, about
310 ft. O.D. A halt was made at a gravel- working near
Cooper's Farm, si niiles from the start. In composition the
gravel is very similar to that of Hazeley Heath, and the Director
thought there must be a slip of the pen in Mr. Salter's statement
{Proc, GeoL Assoc, vol. xv, p. 272) that "the hulk of the
material composing the gravels in this district is derived from
Tertiary strata, and but little from the Wealden." The Director
thought the sub-angular flints of which the gravel mainly consists
were derived from the Chalk, or from older drifts, and he doubted
whether any of the material came from Wealden Beds.f There
are, no doubt, a fair number of flint pebbles from Bagshot
Pebble Beds. A section, 7 ft deep, showed mottled gravel with
scarcely a sign of stratification, and there is a somewhat unusual
absence of stratification in the gravel all over the top of these
flats, and as their level is over 300 ft. O.D., they furnish a good
example of high-level gravel with but little stratification.

The party then crossed the valley of the Blackwater into
Berkshire, and the next halt was at Finchampstead, in Sheet 268
of the Geological Survey Map, New Series.

The green-coloured sands of the Middle Bagshot were seen
below East Court, and at the top of the hill a road-section at
North Court showed yellow Upper Bagshot sand. Scarcely a
sign of bedding is seen in that series, and here and there small
patches of green sand were observed. Finchampstead Ridges
are capped by gravel at a level of about 330 ft. O.D. The
party cycled, by way of Warren Lodge and the Nine-mile Ride,
to some brick-fields between Wellington College and Wokingham,
having ridden 1 2 miles from Winchfield Station.

Up to the present the route had lain over country, which, it is
believed, had not previously been visited by the Association, but
the brick-fields in the Nine-mile Ride received attention on June
2 1 St, 1 890. J

The first pit visited showed a good exposure of the current-
bedded Lower Bagshot sand and above it was a laminated clay
which is worked for brick-making. This, the Director thought,
belonged also to the I^wer Bagshot, but Dr. Irving and others
hold that it is Middle Bagshot, and in any case it is very near the

• See Proc. Geo/, Assoc, vol. xiv, p. 127.

t By the courtesy of Mr. Monckton, I am permitted to say that in the remarks quoted
above, I refer to the Wealden district (not heds)y and that I regard some of the earlier drifts
of this district as probably of Pliocene age. Hence the sentence would read thus : "The
bulk of the material (/.r., the rounded flint pebbles and perhaps the brown sub^mgular flints)
composingthe gravels in the district is derived from Tertiary strata (i.r., Bag^ot or perhaps
Pliocene Drifts), and but little (such as small quartz pebbles and chert) from che Wealden "
district.^K E. Salter.

t Proc. Geol. Assoc.j vol. xi, p. clvi.

EXCURSION TO WAI.TON-ON-THE-HILL. 155

line of division between the two series. The surface of the ground
is formed of gravel of variable thickness with a level of about 240 ft.
O.D., and both the gravel and underlying clay are much contorted.
An excellent example of these contorted beds is shown in a photo
by the Rev. H. P. Kempthome, part of which was reproduced in
the report of a former excursion,* which was under the direction
of Dr. Irving.

On the motion of the President, a cordial vote of thanks to
the Director was passed, and the members cycled to Wokingham
Station, where they arrived at about 6.30 p.m., the total distance
covered having been 15 miles.

REFERENXES.
Geological Survey Map, New Scries, Sheets 284, 268 Drift. Price 3s. each.
Ditto Old Series, Sheet 8 Drift.

1872. Whitaker, W.—** Geology of the London Basin." Mem. GtoL

1883. Irving, A.—" Bagshot Strata." Proc. GtoL Assoc., vol. viii, p. 133.
1886. MoNCKTON, H. W., and IlEKRIES, R. S.— " Bagshot Beds. ' Quart,

Joum. GtoL Src.^ vol. xlii, p. 402.
1890. Irving, A.— »* Excursion to Wokingham, etc." Proc. GeoL Assoc,,

vol. zi, p. clvi.
1892. MONCKTON, H. W.— *' Gravels South of the Thames." Quart, youm,

Gtol. Soc., vol. xlviii, p. 29.

EXCURSION TO NEW RAILWAY,
WALTONON-THE-HILL, AND BETCHWORTH.

Saturday, April 15TH, 1899.

Directors : W. Whitaker, F.R.S., Pres. G.S., and
W. P. D. Stebbino, F.O.S.

Excmsicn Secretary: Bedford McNeili,, F.G.S.
(Report by Mr. Stirhing.)

The members reached Kingswood at 2.2 p.m., and walked
to the cutting on the western side of the tunnel under Walton
Heath, in progress for the Chipstead Valley line. At its
south-eastern end the cutting showed Chalk covered with
pipes of Thanet Sand, and redeposited Woolwich Clay with
flint pebbles ; near the working face at the north-western end the
Thanet Sand seemed to occur in mass. A point of interest,
however, in this cutting was the way in which the Chalk had

• Proc. Cetl. Assoc , vol. xi, p. clxi.

July, 1899.I

156

EXCURSION TO WALTON-ON-THE-HILL.

been worn to a series of pinnacles, divided by holes or pipes
penetrating almost down to the level of the railway ; in some
cases the pinnacles rise to within 4 or 5 ft of the surface.

Thence the party walked to the present working face south of the
Walton Road Bridge and to the site of the Walton Station, passing
what remained of the section figured below. Returning on the
western side of the cutting the party saw a fairly good section of
Thanet Sand with an undulating surface, and two or three
pinnacles of Chalk standing up in it. On the south side of the
Walton Road Bridge, but on the opposite side of the cutting, the
strata in the cutting were the same as those previously seen on the
north side of the bridge, but the movement that had taken place

•fe-

'y\. i/;^

- 3

W.P.D.S.

Section in Railway Cutting, Walton-on-the-Hill.
Feuriary, 1899.

Length of Section, about 35 yards. Height of Section, about 40 feet.

A. Chalk. B. Thanet Sand. C. Buff Sand with pebbles Cstratified).
D. Mottled Clay with pebbles.

owing to the destruction of the Chalk was moie pronounced on
account of its occupying less space longitudinally. The Directors
pointed out that, though the Thanet Sand was marked in the
Drift Edition of the Geological Survey Map as covering a large
patch of the surface of the ground about here, at no spot in
these cuttings did it reach the surface, except in the case of
some pipes at the northern end.

After tea at Walton Mill the party proceeded to a small sand-
pit on Headley Heath, containing sand and a gravel largely
composed of flint pebbles. The gravel occurs in isolated patches
on high ground from Netley Heath eastwards, and is of
uncertain age. Walking southward, the party reached the edge
of the North Downs, near Betchworth Clump. Thence they
descended to the Chalk-pits, which we believe had
not previously been visited by the Association. Here was
seen a section embracing a large part of the Middle and Lower

EXCURSION TO THE THAME DISTRICT. 1 57

Chalk. The Directors pointed out in descending order (i) the
zone of Echinaamus subrotundus^ equivalent to the zone of
TerebratuUma gracilis^ which does not seem to occur here ;
(2) the zone of Rhynchanelia cuvieri^ called by the quarrymen
•* Burr Chalk," and equivalent to the Melboum Rock ; (3) the
zone of Belemnitelia plena^ a very distinct narrow band round
the quarry, and forming the top of the Lower Chalk ; and (4) the
20oe of Holaster subgiobosus. The distinction between zones i
and 2 was very easily seen on one side of the pit The marked
dfference in character between the massive, thickly-bedded
Middle Chalk, and the more thinly-bedded and marly Lower
Chalk was well seen.

REFERENCES.

Geological Survey Map, Sheet 8, Drift Edition, price 8s. 6d.
OrdiuiDce Survey Map, (New Series), Sheet 286, price is.

1862. Whitaker, W.— "On the Western End of the London Basin, etc."

Quart. Joum, Geol. Soc.^ vol. xviii, p. 258.
1872. . — »* The Geology of the London Basin." Mem. GtoL

Survey, vol. iv.
1884. Dalton, W. H.— " Excursion to Epsom and Dorking." " Record of

Excursions,*' p. 86.
3895. MoNCKTON, H. W., and Stebbing, W. P. D.— " Excursion to Bctch-

worth and Headlcy." Proc. Geol. Assoc. ^ vol. xiv, p. 1 24.
J 897. Stebbing, W. P. D. — " On Boulders of Granite from the Middle

Chalk of Betchworth." Quart. Joum. Geol. Soc.^ vol. liii, p. 213.
^898. Whitaker, W., and Stebbing, W. P. D.— *' Excursion to Kings .\ood

and Walton-on-lhe-Hill.'* Proc. Geol. Assoc., vol xv, p. 456.

EXCURSION TO THE THAME DISTRICT.

Saturday, May 6th, 1899.

Director: A. M. Davies, B.Sc, F.G.S.

Excufsian Secretary : W. P. D. Stehbing, F.Cl.S.
{Rep0rt by The Director.)

A SMALL party assembled at Thame Station shortly before noon,
and at once drove along the Towersey road into the adjoining
county of Bucks., where the first turning to the left soon brought
them to a small quarry (p. 39*). Here the Director, after
briefly calling attention to the Chiltern escarpment with the con-
spicuous Whiteleaf Cross showing the Chalk, and the Gault plain
at the base, remarked that the small stone-pits in the Portland of
this district were worked mainly in the winter, and that conse-
quently none of those they would see that day would show
exactly the sections described in his paper. In this case the two
lowest beds were now hidden, and the nodular chert at the top
was but indifferently exposed. The blocks of Portland limestone

* This and subsequent references are to the Director's paper in this volume of
Proceedings ante.

July, 1899.]

158 EXCURSION TO THE THAME DISTRICT.

Stacked near the entrance were full of the characteristic fossils —
Trigonia gibbosa^ Cardium dissimiU^ Pecten lamellosus — and the
members soon collected a number of Paludina, almost all under-
sized, from the Purbeck marl, Bed 7.

The party then drove to the pit near King's Cross
(pp. 40, 41). Here the creamy limestones were found exposed
to a depth of 7 ft, and, among other fossils, Mr. Young
had the good fortune to obtain a Ptrisphitutes (Amm,)
boloniensis of portable size. The greater share of attention in
this pit, however, was claimed by the uppermost clayey and
marly beds, regarded by the Director as probably Middle or
Upper Purbeck. This view was subjected to a severe fire or
criticism, and counter propositions that the clay was Wealden,
Gault, Boulder-Clay, or an artificial deposit in an old cutting,
were quickly raised. After much discussion, the general conclusion
arrived at was that part of the topmost marly portion might per-
haps be artificial, that the rest was of freshwater origin, newer than
the Purbecks of the district, and certainly not Gault nor Boulder-
Clay. These conclusions were not inconsistent with those of the
Director.* It should be mentioned that fragments of carbonaceous
material were found in the black clay, and several unmistakable
Unios in the sandy bed (No. 5), but these were too fragile for
preservation.

The party then walked down the hill to the Dad Brook, along
the line of section (Fig. 2, p. 23, and Map, p. 54). The outcrops
of limestone and sand were seen by the roadside, and lydite-
pebbles were found at the junction of the sands with the under-
lying clay. Among these pebbles Mr. Leighton found a
phosphatised fragment of an Ammonite — a find of interest
\cf, p. 25). At Cuddington creamy limestones were seen to crop
out in the roadside.

The party drove next to Long Crendon. On the way
the Director pointed out the line of the proposed new
railway from Prince's Risboro' to (irendon Underwood, which
may yield some valuable exposures near Haddenham. The
first section examined at Ix)ng Crendon was that by the
southern windmill (p. 22), visited previously by the Association
in 1893. The present visit was opportune, as the owner has
decided not to work it any more. Already the creamy lime-
stones for which it was worked are hidden, and the pale grey clay
(Bed 3, p. 22) could only just be seen at one point. The rest
of the section was still in such good condition as to cause general
regret that no photographer was at hand. Mr. Parker, however,
produced some photographs of the section taken a few years ago.

• I am gl.id to take this opportunity of m.iking a correctio-^, the need for which was
pointed out to me at this point, in the section eiven on p. 40. Beds 7, 8, and g are properly
one hed, the transition from one to the other tieing quite gradual. They were markixl as
such in my field note-book. — A.M.D.

EXCURSION TO THE THAME DISTRICT. 1 59

Mr. Leighton drew attention to Bed 8 of the section (p. 22) as
closely corresponding to the basement-bed of the Gault at
Folkestone and elsewhere ; a hunt was made in it for fossils, and
a shark's tooth was found by Miss Foley.

The sections on the steep descent of the road to Thame were
next examined (p. 21). After the lower l)eds of the limestone
sequence had been examined the outcrop of the same beds in the
roadway was observed, and someof the members maintained that the
dip shown by these beds would carry them below the sands seen in
the next exposure down the hill. The Director said that this was
not the case, as he had assured himself at more than one point
that the sands passed beneath the limestones. He dismissed the
suggestion that the sands were Lower Greensand by the assertion
that they were ** too green," the absence of glauconite being in
this district a characteristic of the "Lower Greensand." He
maintained that the lydite-bed here seen with 10 ft. of sand
visible below was on the same horizon as the lydite-bed which
they had seen immediately above the Hartwell Clay at Dadbrook
Hill A hasty visit to the brick-field at the foot of the hill tended to
confirm this view in so far as the clay there was seen not to resemble
Hartwell Clay, at any rate lithologically, being rather shaley, and
not sandy at all. The same was the case at Thame, the Director
said, where he had that morning seen the base of the sand ex-
posed in a drainage cutting, and had been told by the engineer
that the clay beneath the sand was very stiff.

REFERENCES.

<yeological Survey Map (i inch scale), Sheet 13 (price 8s. (xl.) and 4$ S.K.

(price 38.).
<Jcolog^ca! Survey Index Map, Sheets 11 and 12. Price 2s. 6d. each.
Ordnance Survey Map, New Series, Sheet 237, Thame. Price is.

1836. W. H. FrrrON.—** Strata below the Challc. Tram. Geol. Soc,, ser. 2,

vol. iv, p. 163.
1864. A. H. Green. — '* Geology of the Country round Banbury, etc." (Sheet

45). Mtm, Geol. Survty,
1880. J. K. Blake,—" Portland Rocks of England." Quart. Joum. Geol. Soc ,

vol. zxxvi, p. 189.

1893. . — *' Excursion to Brill." Proc. Geol. Assoc., vol. xiii, p. 71

1895. H. B. Woodward.— "Jurassic Rocks of Britain." Vol. v, pp. 220,

221, 279, Mem. Geol. Sun'ey.
1899. A. M. Davies. — ** Contributions to the Geology of the Thame Valley."

Proc. Geol. Assoc., vol. xvi, p. 15.

i6o Excnisiox TO ILFOROl

EXCXRSION TO ILFORD.

May 13TH. 1S99.
DtFtcUnr: T. V. Holmes, F.G.S.

BxzmrJtm. S*crr*mry : W. P. D. Sttctt^s, F.GuS.
iXtpmrt hj Tkc D?«kto«.)

The members kft Liveqxwl Street Statioo at 2 p.m^ airiTiiig at
Dford at 2.15. They tben walked to the Cauliflower Brick-
field, the property of Mr. R. Page, who had kindly given
permission for its inspection. The side of this pit showed 1 2 to
14 ft. of brick-earth above sand.

The Director remarked that the old rirer deposits of the
Thames and its tributaries, on which they were standing cohered
a broad belt of flat country lying between the allavial flats
bordering the Thames (which constituted the most recent river
deposits) and the higher ground of London Clay north of
Wanstead, Romford, and Upminster. The levd of this tract
varied from more than 100 ft. above the sea, towards its northern
limits, to 15 or 16 ft. dose to the marshes of the Thames between
Barking and Rainham. Between London and Gravesend, as
between Windsor and London, the Thames had not only been
cutting its valley deeper and deeper, but had also been occupied
in taking a more southerly course than it once followed. This
was shown by the much greater breadth of river deposits to the
north than to the south of the present stream. It should also
be remembered that the fall of the river would make a deposit
60 or 70 ft. above Ordnance Datum west of London, for example,
the equivalent of a bed at a considerably lower level east of that
city. Around the Ilford brick-pits the sur^sure level is from 40 to
50 ft. But Thames Valley Gravel had been seen at a height of about
100 ft. above O.D.,* on the new railway between Upminster and
Romford, overlying the Chalky Boulder-Clay, the latest deposit o
the Glacial Period in that part of England. The Ilford deposits
must therefore be still more decidedly " post-Glacial " in the only
sense in which the term can be used, that is in the sense of being
more recent than the Chalky Boulder-Clay.

These old river-deposits consist of sand and gravel occasion-
ally capped, as at Ilford, by a considerable thickness of loam or
brick-earth. The gravel and sand has, doubtless, been brought
down in the channel of the stream, while the brick-earth is
inundation-mud, deposited above the sand and gravel during
floods. Mammals would be especially liable to be drowned

• Quart. J^urn. Geol. Sac,, vo xlviii (iS^z). p. 365, and vol. 1 (1894X P- 443-

July, iSqq]

EXCURSION TO ILFORD. l6l

during floods, while at the same time their remains, when quietly
buried in the comparatively impermeable mud, would have a
much better chance of preservation than if brought down in the
channel of the stream.

The Director concluded his remarks by referring to the most
important and interesting of the mammalian remains which had
been found at Ilford. In answer to a question as to the origin
of the curious steep-sided hollows, filled largely with other
material, often seen near the surface of the brick-earth, the
Director replied that they had probably originated in natural
cracks, the result of drying and shrinking, which in many cases
had been b^un when the brick-earth was being deposited.
These had been enlarged by the action of the weather,* and
ultimately filled up with material at various periods and from a
variety of sources.

Recrossing the railway, the party proceeded along the
Romford road in a north-easterly direction. Passing the new
Seven Kings Railway Station, they entered, by permission of the
G. E. R. Company, the large ballast-pit on the northern side of
the Romford road, about midway between Seven Kings and
Chad well Heath Stations. There they found 12 to 14 ft. of
gravel capped by 3 or 4 ft. of brick-earth. The section was very
fresh and clear, and the gravel was seen to be very well stratified
and uniform in composition.

A vote of thanks having been accorded to the Director, on
the motion of Mr. E. T. Newton, the party glanced at the old
G. K R. ballast-pit, south of the road, and made their way to
Seven Kings or Romford Railway Stations.

REFERENCES.
Geological Survey Map, Sheet i, S.W., Drift Edition.

1S71. Dr. H. Woodward,—" Record of Excursions," p. 173, and Proc. GeoL

Assoc.y voL ii, p. 273.
18S9. W. WHrTAKER.— " The Geology of London." Afem. Geoi, Survey^

pp. 410-415.
1890. B. B. Woodward.— " The Pleistocene Mollusca of the London

District." Proc, Geoi. Assoc. ^ vol. xi, pp. 365-371, 388.
1893. F. C. J. Spurrell.—" Excursion to Ilford." Proc. Geol, Assoc.,

vol. xiii, p. 53'

l62 EXCURSION TO REIGATE.

EXCURSION TO REIGATE.

Saturday, June 3RD, 1899.

Directors : Miss M. C. Crosfield and the Rev. R. Ashington
BuLLEN, B.A., F.L.S., F.G.S.

Excursion Secretary: A. C. Young, F.C.S.
{Report by Miss Crosfield).

The party met at Reigate Station about 2.30, and first visited a
sand-pit in the Croydon Road where the junction of the Gault
and Lower Greensand is well seen. Phosphatic nodules and
fragments of wood were found, but no fossils. Crossing the
Gault on Wray Common, the company walked westward by
Raglan Road at the foot of the Upper Greensand escarpment,
and thence to a pit in Upper Greensand just below Colley
Hill, where the following section is exposed : At the top,
Chloritic Marl, 7 ft. 6 in. ; Cherty band, 6 in. ; Hearthstone,
6 ft. ; Cherty band, 6 in. ; Hearthstone, 5 to 6 ft. ; Fire- and
building-stone, 6 ft. Sponge spicules occur abundantly in the
cherty bands. Two small faults were distinctly visible. In the
" Horseshoe" quarry (450 ft. O.D.) adjoining, Mr. George Taylor,
on whose property the Association was now assembled, met the
party. He stated that the tunnels recently discovered in the
hill were 200 years old. From borings made for water, he found
that the thickness of the Upper Greensand here was about 55 ft.
After a vote of thanks had been passed to Mr. Taylor, the Rev.
R. Ashington Bullen described the Holocene deposit in the same
quarry. It is 4 ft. thick, and yielded Bulimus montanus^
Helicigona arbustorum, and Clausilia rolphii^ no longer extant
there. Tertbratulina gracilis from the Middle Chalk, and an
abnormal facetted nodule (Hydrated MnO), probably from the
Upper Greensand, occurred. The abundance of Arion ater
(granules) and Carychium minimum at 2 to 3 ft. levels attest
moister conditions than now obtain.'-' A Neolithic scraper
occurred at a depth oi ?.\ ft. A few of the members scaled
Colley Hill to see a block of ferruginous conglomerate, measuring
46 in. X 40 in. x 24 in. Mr. H. W. Monckton considers this
mass of cemented angular and rounded pebbles to be a relic of a
deposit of sand, etc., similar to that which has been mapped at
Chipstead 2\ miles N.E., and to a larger patch at Headley Heath
2^ miles N.W. from the site of the block under discussion.
Unfortunately, this conclusion does not carry us very far, for the
deposit is mapped and described as " Sands of Doubtfuk Age."t
A visit was then paid to the Reigate Hill pit in Lower and Middle
Chalk.

• P*oc. Malacological Soc., vol. iii.

t Whiiakcr, ** Geology of the London Basin." Me/tr. GeoiogictU Survey, vol. iv,
p. 336ri872X

July, 1899.]

PROCEEDINGS. 163

REFERENCES.

Geological Survey Map (i in. Scale), Sheet 8, Drift. (8s. 6d.)
Geological Survey Index Map, Sheet 12. (2s. 6d.)
Ordnance Survey Map (New Edition), Sheet 286. (is.)

1887. TOPLEV, W.—*' Excursion to Redhill and Reigate." Proc. GeoL

Assoc. ^ vol. X, p. 154.
1889. VVdlFAKEK, VV.—" Geology of London." Mem. Geol. Sunn.

EXCURSION TO STAINES.

Saturday, April 2 2nd, 1899.

Director-, W. Whitaker, F.R.S., Pres. G.S.

Excursion Secretary: Beufoku McNeill, A.R.S.M.
(Refiort by H. .\. .\llen.)

A LARGE party arrived at Staines at 2.36 p.m., and at once
proceeded to the offices of the Water Companies, where a large
series of mammalian remains had been arranged for inspection.
The specimens were obtained from the Alluvium during the
progress of the works. The geologists next walked to the
aqueduct, excavated in Alluvium and River Gravel. Thence they
-were conducted, by train kindly placed at their disposal by
Messrs. John Aird and Co., to the reservoirs in process of
construction. The Director explained the geology of the district,
.sind stated that the reservoirs are cut through river gravel to
London clay, the junction being fairly even.

In the absence of Mr, R. E. Middleton, M.I.C E., the
^^idance of the members was kindly undertaken by Mr. M. B.
Duff, the resident engineer. The method of making a puddle-
trench (of London clay) through a mass of gravel resting on clay,
so as to render it capable of containing a body of water 4 1 2 acres
in area, was clearly explained. The average depth of water will
T)e 31 ft., maximum depth 39 ft. Attention was next directed to
^he fine sections of London clay and gravel exposed.

Many large blocks of greywether sandstone, which had been
::found in the gravel, were seen. One mass was observed in the
T)ank by the Director ; the bottom part of it was soft and could
^l)e readily disintegrated into sand.

ORDINARY MEETINC;.

Friday, March 3RD, 1899.

J. J. H. Teall, M.A., President, in the Chair.

The following were elected members of the Association :
IVilliam J. Stokes and F. L. Kitchin, M.A., Ph.D.

In the unavoidable absence of Dr. Abbott, through illness, a
lecture was delivered by Mr. G. W. Lamplugh on the " Geology
of the Isle of Man," dealing more particularly with the glacid
July, 1899.]

1 64 PROCEEDINGS.

phenomena. The lecturer gave a lucid account of his observa-
tions in the island, and illustrated his remarks by some excellent
lantern slides taken by Prof. Watts.

ORDINARY MEETING.

Friday, April yxH, 1899.

J. J. H. Teall, M.A., President, in the Chair.

The following were elected members of the Association :
W. Edwards, F.G.S., and Howard Fox, F.G.S.

The President then read a paper by Dr. Charles Barrois on
" The Geology of Brittany," with special reference to the Whitsun-
tide Excursion.

ORDINARY MEETING.

Friday, May 5TH, 1899.

J. J. H. Teall, M.A., F.R.S., President, in the Chair.

The following were elected members of the Association :
Arthur S. Home, N. Alexander Mackie, Arthur W. Clayden,
M.A., F.G.S., A. R. Hunt, William E. Hughes, B.A., F.G.S.,
J. Allen Howe, William Arthur Savage, M.R.C.S., L.R.C.P.,
etc., J. A. Rimmington, Miss A. T. Barnard, Miss K. A. Burke,
E. B. B. Newton.

Mr. H. J. Osborne White read a paper, by Prof. W. M.
Davis, of Harvard University, entitled "The Drainage of
Cuestas," the paper being illustrated by diagrams.

ORDINARY MEETING.

Friday, June 2nd, 1899.

J. J. H. Teall, M.A., F.R.S., President, in the Chair.

The following were elected members of the Association :
H. Bauerman, F.G.S., J. W. Jarvis, the Right Hon. Sir John
Lubbock, Bart., M.P., F. Nichols, Alfred B. Trestrail.

The following papers were read :

"The Pleistocene Deposits of the llford and Wanstead District," by
Martin A. C. Hinton.

"The Pleistocene Mollusca of llford," by A. S. Kennard and B. B
Woodward, F.L.S., F.G.S.

" The Raised Beach and Rubble Drift at Aldrington, between Hove and
Portslade-by-Sea, Sussex, with Notes on the Microzoa," by Frederick
Chapman, A.L.S., F.R.M.S.

Mr. G. E. DiBLEY exhibited a specimen of Goniaster^
embedded in flint, from the Middle Chalk of Cuxton.

i65

A SKETCH OF THE GEOLOGY OF THE

LOWER CARBONIFEROUS ROCKS

OF DERBYSHIRE.

WITH SPECIAL REFERENCE TO THE LONG
EXCURSION OP Z899.

By H. H. ARNOLD BEMROSE, M.A., F.G.S.

PLATES III— VI L

(Read July 7th, iSgg,)

COxNTHNTS.
,-_. PAGE

J^'^Or^L'CTION i6s

]^"^*- Rock Formations 169

*^^isTAiN Limestone 169

-^-"ViN iNLiER 169

J^S HOVER INLIER 17s

^^ICH Inlier 175

•^ i>* ivETON Inlier 17S

V-'-'Va'brns and Underground Water 178

V'^-^D AND Lead Mining 182

y _^* ^TAMORPHIC LIMESTONES 184

j^jj *^^dale Rocks i86

5 *J^^STONE Grit 189

^^NJx^SAND FlRE-CLAVS I92

Q^jry^^iAh Drift 193

j^^T^^^^-AREOLS TlIFA AND WaRM SPRINGS I94

prrwl?^^^ ^^^*^^ '95

REK^^^«APHY 213

*^^NCES 220

INTRODUCTION.

1^ ^E district described in this sketch includes the north and
. . north-west portions of Derbyshire, and roughly coincides
^ Vv^^^ whole of the High Peak Division and the northern half
ol tt\e Western Division of the county. It consists of the hill
c^^titry of Derbyshire, which forms the southern spur of the
^^^tiine Chain. The town of Glossop is on the north-west;
^^Xton and Chapel-en-le-Frith are on the west ; Castleton, Hope
^^ Hathersage near the centre, Matlock, Crich, and Amber-
6^^^ are on the east, and Ashbourne, Kniveton, and Wirksworth
^ the south. It lies east of the watershed of the central part of
^^gland, and is drained by the Derwent and the Dove, which
ft^>r into the Trent.

The Derwent rises in the moorlands in the northern part of
August, 1899.] 13

1 66 H. H. ARNOLD BEMROSE ON

the county, and for some distance forms the boundary between
Yorkshire and Derbyshire. It flows in a south-easterly direction,
and after passing through Hathersage, Rowsley, Matlock, Amber-
gate, and Derby, flows into the Trent beyond Draycott. The
Alport and Ashop rise on Alport Moor, and in the course of a
few miles unite at Alport Bridge, and finally enter the Derwent
at Ashopton. The Not rises on the flanks of Kinder Scout, in
Edale, flows through the valley of that name, and joins the
Derwent, at Mytham Bridge. The Wye rises on the northern
flank of Axe Edge, near Buxton, flows through Buxton, Miller's
Dale, Monsal Dale, and Bakewell, and joins the Derwent at
Rowsley. The Amber rises a few miles north-west of Ashover,
and enters the Derwent at Ambergate. The Dove^ which for
some distance forms the boundary between Staffordshire and
Derbyshire, rises on Axe Edge, flows through Hartington, Dove
Dale, and Ashbourne, into the Trent near Burton.

A well-marked anticline passes through the district in
a north-west direction. The beds dip steeply to the west,
under the Coal Measures of Lancashire and North Stafford-
shire, and with a more gentle dip to the east, under those of
Yorkshire and Derbyshire. In the north of the county a large
dome-shaped mass of Mountain Limestone has been brought up.
The severed strata on the west and east sides of the anticline,
which were once continuous across the arch, have been removed
by denudation which has not only laid bare the Mountain Lime-
stone, but removed a small thickness of the upper beds. If we
were to start on the Mountain Limestone and travel a short
distance in an easterly or westerly direction, we should pass the
various members of the Carboniferous series of rocks in succes-
sion up to the Coal Measures.

A smaller anticline runs through Ashover, parallel to that of
the Pennine Chain. At Matlock the limestone dips to the
east beneath the Yoredales and Millstoue Grit series, which form
a small basin and soon dip west. This dip and the fall of the
ground in the valley of the Amber expose the beds down to the
Mountain Limestone at Ashover. Fig. i gives a rough section
across the county from Buxton on the N.W. to Stretton on
the S.E.

The Mountain Limestone from Doveholes through Castleton
and Bradwell to Eyam is bounded by a narrow belt of lower
ground consisting of Yoredale shales. Slopes which run nearly
parallel to the limestone boundary rise from this depression.
These slopes are the edges of several outliers of Shale Grit which
once formed a large plateau extending from Chapel-en-le-Frith to
Eyam, and including the moors in the extreme north of the
county. Edale, and the valley of the Derwent near Hope,
Bamford and Hathersage, have divided this plateau into several
outliers.

THE LOWBJl CAHBOSIFKROCS ROCKS OF DERBY^HIRK. 167

S, 2

2 LI

3 5 ^
^ -I

ar Near the centre of the

^ % Shale Grit-plateau is an outlier

of Kinder Scout grit which is

called the Peak. Thouj^h it

is a dat table-land it reaches a

height greater than any other

part of DKsrbyshire, some portions

f of it being ^,000 ft. above the

I sea. The highest point in the

limestone area reaches a height

of only 1,800 ft. The Shale

Cirit dips under the Kinder

Scout grit, which on the west

tbrms a ridge from Chapel-en-le-

^J:WS Frith through Hayfield to

Glossop> and on the north ex<

tends some distance east from

Glossop into Yorkshire. On

i^ the west this grit forms the escar^v

1 ments of Derwent and B:\nit'ord
= Edges. The \-arious members of

the Millstone Ttrit ga>u^>s xx^y be
traced as far south as Bel|H.*r.
The Chatsworth or Rivelin
^rit forms the tine escarpments of
Froggat, Curl>ar» and l^slow
Edges, east of Stoney Middleton.
The southern p^ut of the lime-
stone area is bounded by the
Yoredale shales, which in turn
^ are covered unconformably by

r the Triassic rocks of the

\ Midlands. On the west as far

as Doveholes the limestone is
bounded by the Yoredale rocks,
though the lx)undar)- is often
faulted. Near Hartington is an
■X outlier of Millstone Grit on

2 Sheen Hill in Staffordshire.
I .\bout Earl Sterndale the

boundary is much complicated

by faults, and west of Huxton

the limestone is faulted against

the Yoredales and Shale Grit

PI which dip under the Millstone

g, Grit of Axe Edge and the Goyt

ill Basin. Between Buxton and

Doveholes the limestone is

1 68 H. H. ARNOLD BEMROSE ON

bounded by the Yoredale rocks, which dip under the Millstone
Grit of Combs Moss on the west.

The district is noted for its fine scenery. The Mountain
Limestone, with its outlines generally smooth, its well rounded
grassy slopes, and deep, narrow dales and ravines, presents a
marked contrast to the wild moorlands and escarpments of the
Millstone Grit. These narrow dales or gorges have sometimes a
stream at the bottom, whilst at others the valley is quite dry, the
water having found its way underground. Some of the dales
probably have been formed by the falling in of the roof of an
old underground watercourse, but others — especially that of the
Derwent, at Matlock — are to be explained in a different manner.
The river, after flowing in the broad valley of shale from Darley
Dale, suddenly enters the Mountain Limestone which rises across
its path, instead of continuing in the shales and skirting the
limestone as far as Cromford. The course of the river evidently
was determined before the valley of Darley Dale was formed,
and the cutting of the gorge in the limestone and the broad
valley in the shale proceeded together.

The Wye and the Dove also illustrate the influence of
different rocks in the erosion of river- valleys. The Wye, in its
course from Buxton to Monsal Dale, flows through a deep
valley in beds of massive Mountain Limestone. At Chee Tor
and at Cressbrook the stream has cut a narrow gorge, bounded by
almost perpendicular cliffs. These steep slopes are often covered
by ivy and shrubs, which contrast strongly with the bareness of
the limestone. When the river reaches the thin upper beds of
limestone, the valley becomes wider, and in the broad shale-
valley near Haddon Hall, the Wye pursues a serpentine course.
The Dove, after flowing in the shales near Hartington, enters
the limestone near Beresford Hall, and its course for several
miles consists of the narrow valley or gorge known as Dovedale.
It then enters the shales again near Thorpe, and the valley
becomes wider and less rugged.

In the gritstone country some valleys run parallel to the strike.
They often lie between two escarpments of grit which are
separated by a bed of shale. A good instance is given b>"
Messrs. Hull and Green in the valley of Ashop Clough. The
south side of the valley is formed by an escarpment of grit
resting on a thick bed of shale. The north side is formed of a
dip slope of a sandstone bed which crops out from under the
shale. The river runs along the top of the lower sandstone with
a steep cliff of shale on the south which it is undermining and
wearing back.

A third class of valley is caused by streams flowing down the
escarpment of one of the parallel valleys, and cutting back inta
the hill until at length a transverse valley is formed.

The chief points of geological interest in the Mountain.

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 169

Limestone, besides its fossil contents, are undoubtedly the igneous
Tocks, the lead mines, the caverns and underground watercourses.
From a very early date lead, zinc, and other minerals have been
obtained from the limestone. The rock is also largely quarried
for making lime, road metal, and for building purposes. It also
provides sand and clay for fire bricks, and chert, which is used
largely in the Potteries.

THE LOCAL ROCK FORMATIONS.

The following rocks occur in the district covered by this
•sketch.

-'Decent. — Alluvium. Peat Bogs. Calcareous tufa, stalactiiic formations.
F*LEISTOCENE. — Cavern deposit?, Glacial drift, boulders, sands, and clays.

Upper Carboniferous, Millstone Grit i. Roujjh Rock.

Shale.

2. Sandstones and Shales.
Shale.

3. Chatsworth Grit.
Shale.

4. Kinder Scout Grit.
Shale.

5. Shale Grii.

1. Shales with thin Sandstones.

2. Shales with thin beds and no-
dules of earthy Limestones.

Limestone with thin Shales and
clay partings.

Lower Carboniferous.

Yoredale

Mountain or
Carboniferous
Limestone

I o 1 ( Contemporaneous with the\ ore-

IgneousKocks » jit-. jm

^^- I , X \ dale Lunestones and Mountam
( 1 oadstone ) . i » • . i t • . •

^ ( Lmiestone and also intrusive.

The above divisions of the Carboniferous series are those
^^^opted by the Geological Survey.

The Shale Grit was formerly placed amongst the Yoredale
^Ocks under the name of Yoredale Grit, and as such it appears on
^^e i-inch geeological maps of Derbyshire which were made about
^fty years ago, and revised up to about the year 1 867. Since then it
^as been transferred to the Millstone Grit, and forms the lowest
Member of that series. Some further remarks about these
^divisions will be found under the head of Yoredale Rocks.

The Mountain Limestone.

The Mountain Limestone, of which all but a small portion on
the S.W. is in the county of Derbyshire, forms an irregularly
shaped inlier, measuring about twenty miles from north to south,
and ten miles from west to east. In addition to this there are
three small inliers, viz., at Ashover and Crich on the east, and at

lyo H. H. ARNOLD BEMROSE ON

Kniveton on the south-west. The large inlier is a pericline or
dome, the longer axis ranging N.N.W. The beds dip away from
the centre of the mass in every direction, and, generally speaking,
the dip at the edges is at right angles to the boundary, which,
according to the geological maps, is partly natural and pardy
faulted. The dip on the west is generally greater than that on
the east.

A closer examination of the limestone area shows that this
conception of a simple pericline must be modified, and that it is
made up of a number of smaller domes and basins.

The three promontories in the limestone on the east, and on
which Stoney Middleton, Bakewell, and Matlock Bath are
situated, are portions of minor domes, whilst the bay in the lime-
stone near Ashford, which is occupied by the Yoredale rocks and
the still larger one containing the Stanton outlier of Kinder Scout
grit, represent basins in the limestone. So that a section drawn
nearly north and south from Eyam to Carsington would show at
least three anticlines and two synclines. A parallel section on
the west would show at least two anticlines and one syncline.

A detailed acquaintance with the district shows that though
sometimes the beds (especially those near the centre of the
area) are horizontal, at others they have been thrown into
numerous folds.

The limestone is the lowest rock in Derbyshire. Its thick-
ness is unknown, the basement beds not having been reached.
Owing to the expense of working at great depths, and the
difficulty of keeping out the water, coupled with the fact that the
upper beds have been found to be richest in ore, mining shafts
have been sunk to no great depth. In estimating the thickness
reached, we therefore have to rely on the sections seen in the
valleys. The section made by the officers of the Geological
Survey along the Midland Railway, between Monsal Dale and
Buxton, shows a thickness of nearly i,6oo ft. for the limestone
and igneous rocks or toadstone associated with it.

Section of the Mountain Limestone between Monsal Dale and
Buxton :

ft.

1. Thinly bedded limestone, somewhat earthy, with layers and

nodules of chert, and thin shale partings in the lower beds 250

2. Thickly bedded limestone 50

3. Thinly bedded limestone with chert 90

4. Toadstone, perhaps in places as much as ... ... ... 100

5. Massive white limestone. Miller's Dale rock, with perhaps

a bed of Toadstone in the middle, at least 320

6. Toadstone, a l)out 20

7. \'ery thickly bedded white limestone, Chee Tor Rock ... 500

8. Limestones, more or less concretionary, with shale partings 150

9. Limestones, some thickly and some thinly bedded ; of

these there is seen about lOO

Total thickness shown without reaching the bottom ... 1,580

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 17I

The following approximate estimate was made by the author,
based on the observed dips of the rocks, and taking into account
the rise and fall of the ground. A continuous section was not
seen, and it is probable, from indications of a slight roll of the
beds north of Grange Mill, that the estimate is somewhat in
excess of the truth.

Section from Winster to Grange Mill, N. to S,

ft.

Limestone, cherty in the upper part ... 641

Toadstone (lava) 147

Limestone 911

Toadstone (Bedded Ash) 93

Limestone 508

Toadstone (agglomerate of Grange Vent) —

Total 2,300

A short distance south, the anticline is passed ; so that these
are the lowest beds reached in this part.

With the evidence at present at our disposal, we may con-
clude that a greater depth than 2,000 ft. has not been reached,
and that the lowest beds seen are probably those at Grange Mill
or in the Valley of the Wye, near Pig Tor Tunnel, between
Miller's Dale and Buxton.

For a long time it was thought that the limestone of Derby-
shire was readily divisible into the first, second, third, and fourth
limestones. Whitehurst, Farey, and White-Watson considered
that there were three beds of igneous rock, locally known as
Toadstone, which were found throughout the limestone, making
definite horizons in it and dividing it into four parts. Farey
went so far as to attribute special characteristics to each of these
limestones.

The following sections by Whitehurst and Farey, which are
placed side by side for comparison, illustrate the divisions they
made. Whitehurst's section is between Grange Mill and Darley
Moor. Farcy's is from Riber Hill on the east, to Masson Low,
near Matlock Bath, on the west.

Whitehurst.

Farey.

Date, 1792.

Date, 181 1

ft.

1st Limestone ...

... ISO

150

1st Toadstone ...

... 48

2nd Limestone ...

... ISO

ISO

2nd Toadstone ...

... I3»

3rd Limestone ...

... 180

204

3rd Toadstone ...

... 66

4th Limestone ...

—

Total 732 744

172 H. H. ARNOLD BEMROSE ON

Whitehurst inserts a band of clay between every two adjacent
beds of the above section. Some thirty years ago, the officers of
the Geological Survey considered that these formal divisions of
the old geologists must be given up. Mr. Green wrote : " We
should not be surprised to find lava-flows or deposits of volcanic
ash very irregular in their occurrence, and all the evidence yet
collected tends to show that, among the Toadstones of Derby-
shire, some die out and others take their place on a different
horizon."

The comparative sections given by the Geological Survey
show that the beds of toadstone in different parts of the district
cannot safely be identified. The beds passed through in mining-
shafts prove that a bed of toadstone is present in one place and
absent in another. This fact was known to the old geologists,
who admitted that, in addition to the three beds, there were
chance beds of toadstone. Recent work has proved Mr. Green's
expectation to be correct, the igneous rocks undoubtedly being
of limited horizontal range, and on different horizons in different
localities.

Instead, therefore, of the igneous rocks dividing the
limestone into four definite portions and enabling us to identify
them in the different parts of the district, the stratigraphy of the
limestone will have to be worked out in detail, both palaeontolo-
gically and lithologically, before we can arrive at a complete
sequence of the Derbyshire Carboniferous volcanoes.

Though the Carboniferous Limestone is distinguished by the
number and variety of fossils which have been obtained from it,
no attempt has been made to work out the palaeontology of the
different beds. Collectors have been satisfied with obtaining the
fossils, and only in a few cases have noted the exact localities in
which they occur.

Of the 500 species in the list made by the Geological Survey,
the precise localities of only a small number have been ascertained,
the remainder having no geographical value though known to
occur in the Mountain Limestone of the county.

Prodtfctus, encrinites, and corals are perhaps more common
than any other fossils. The Polyzoa are well represented.
Amongst the MoUusca are numerous lamellibranchs, gastero-
pods and cephalopods. A few species of fish have also been
found.

Productus giganteus is found in large quantities in the upper
beds of the limestone, though it is by no means confined to them
At Crich, a bed consisting almost entirely of this species occurs
about 220 ft. below the top of the limestone. Corals are
frequent in some of the lower massive beds in the neighbourhood
of Miller's Dale, and are found in many localities. Encrinites are
very numerous, and thick beds are often composed of the broken
stems. At Monyash large slabs of encrinital limestone are

:::'r '."WK < \k! ■ 'N! ■ i lO •• - I-.m-x- "i i 'I . U l;\ > H 1 K K. I73

arred m what arc probably upper beds of the Mountain
LniL stone. In the limestone above the bedded ash at Litton
corals, crinoids, polyzoa, brachiopods, lamellibranchs and
gasteropods have been seen. The beds in which they occur are
at least 140 ft. down in the series. Although many limestone
beds appear to the naked eye almost or entirely destitute of
fossils, it is very seldom that numerous foraminifera have not
been detected in them by the author when the specimens have
been examined under the microscope.

Bands or wayboards of clay and also thin shale-partings occur
amongst some of the massive beds. These wayboards are
probably only local, although the miners have a strong belief in
their wide horizontal range, and attempts have been made to
identify them in different localities. A clay which sometimes
occurs twenty fathoms below the toadstone is called the Twenty
Fathom Clay by miners, but it would be impossible to identify clays
of that name in different localities, unless we had evidence that
the beds of toadstone under which they occu'-red were on the
same horizon in each locality. Sometimes these clay-partings
are numerous. An old section called a "vertical section of
strata in the mineral liberties of Wirksworth," which is in the
possession of Mr. Killer of Hoptonwood, near Middleton (who
kindly allowed the author to copy it), shows no less than
fifteen clay-partings in 700 ft. of limestone. Fourteen of these
partings vary in thickness from one to six inches, and one
attains a thickness of ten fathoms and diminishes to one
fathom.

A thin bed of impure coal was found in the higher beds near
Matlock Bath, and also in Combs Dale near Stoney Middleton.
Catamites were found about 170 ft. below the top of the
Mountain Limestone at Matlock Bath, and have been lately
discovered by the author in a thin bed of shaly limestone,
probably some 1,200 ft. down in the series, near Topley Pike.

Many of the limestone beds were formed in water compara-
tively still and free from mechanical sediment, but the shale and
clay - partings found amongst the massive beds point to brief
interruptions in these conditions.

The Mountain Limestone varies in structure, composition,
and colour. It is often an almost pure carbonate of lime, white
or light grey or blue in colour, and breaks with an irregular and
sometimes conchoidal fracture. The dark grey and black
varieties often contain bituminous and argillaceous material.
Some of the beds appear to have originated from reef-like
accumulations, like those of existing coral reefs and shell beds,
others are more or less fragmental and formed of broken corals,
crinoid stems, and brachiopods and other shells which have been
spread out on the sea floor. Sometimes all traces of fossils have
been obliterated by dolomitization and silicification of the lime-

174 H. H. ARNOLD BEMROSE ON

Stone and its contents. The fossils vary very much in the
amount of detrition they have undergone. They are often very
well preserved, so that the convolutions and spiral bases are
clearly marked. In other cases they appear to have been much
worn by water-action. The occasional occurrence of grains of
quartz and of a previously consolidated limestone in the Car-
boniferous Limestone (though Derbyshire is not given as the
locality) was pointed out by Dr. Sorby in 1879.

Since then, these water-worn fragments have been found to be
common in the Mountain Limestone of Derbyshire. Mr. Wilson,
in 1880, discovered, a short distance south of the Winnats near
Castleton, an oolitic limestone containing water-worn pebbles of a
more compact and darker coloured limestone. The pebbles
varied in size from a pea to a bean and upwards, were usually more
or less flattened, and lay with their flat sides roughly parallel
with the bedding. Foraminifera were present in the rock and its
pebbly contents. Three species, viz., ValvuUna pnlaotrochus^
Ehren., Endothyra bowmanii^ Phil., and Archadiscus karreri^
Brady, were found in this rock and in other beds in the
neighbourhood.

In 1896 Messrs. Barnes and Holroyd discovered a sea beach of
Carboniferous age which was well exposed in a quarry near the
Speedwell Mine, Castleton. The rock was described by them as
a conglomerate, the bulk of which was made up of water-worn
shells arranged nearly parallel to the bedding planes. They alsa
found rolled limestone pebbles in the upper limestone at Sparrow
Pit and Windy Knoll, and at the latter place oolitic limestone.
They conclude that the limestone at Castleton and in the imme-
diate neighbourhood is a shallow water deposit. They have also
traced somewhat similar beds in other parts of the limestone
district. It does not, however, appear from their researches
whether they have been able to obtain clear evidence of the bed
being continuous from place to place. If such evidence were
forthcoming, an object to be desired, viz., a datum line in the
Mountain Limestone, would have been obtained.

It is quite possible, however, that detrital beds of this kind
may be found at different horizons in the limestone, and that they
do not extend for any great distance. Fragments of previously
consolidated limestone, often containing foraminifera, have been
found by the author in parts of the Mountain Limestone area,
and on different horizons, and also in the Yoredale limestones.
There seems little doubt that these detrital limestones have been
formed at least in comparatively shallow water. The fragments of
which they are composed must have been consolidated and broken
up again before they were finally deposited.

The upper beds of limestone are generally thin, and contain
numerous bands and lenticles of chert. In some places there is
a second series of chert beds separated from the first by massive

THE lOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 175

iimestones, and chert nodules are often found still lower in the
scries. The upper and lower surfaces of the chert beds and
lentides are seldom parallel, but have a wavy outline ; nodular
masses frequently branch off into the limestone above and below
the parting of chert. The chert is sometimes in rows of isolated
nodules roughly parallel to the bedding-planes of the lime-
stone. Silicil^ed corals, foraminifera and encrinite stems are
often found in the chert, and the casts and stems of the latter
Fossils are locally known as "screws." Small rhombohedra of,
probably, dolomite occur in the chert amongst the upper beds of
limestone.

Hie Ashover Inlier, — About four miles north-east of Matlock
is a small inlier of Mountain Limestone with an intercalated bed
of volcanic tuff. An anticline passes through Ashover in a
N.N.W. direction. The River Amber has cut its way along this
2K.nticline through the Millstone Grit, Yoredale rocks and part
of the Mountain Limestone, into a bed of tulT which forms the
l:K>ttom of the valley. The escarpments of grit are seen on both
sides of the valley above the limestone. In a direction north-
^^ards from Ashover the succession of rocks from the limestone
xsp to the Coal Measures are passed. According to Pilkington
^40 yards of shale were sunk through in the Gregory Mine before
^lie limestone was reached. A short distance east of the inlier
^lie Trinity Chapel fault brings the Coal Measures against the
'^^arious members of the Millstone (irit series. The upper beds
of limestone contain Productus^ encrinite stems, and layers and
»^odules of chert. The limestone near West edge, N.W. of
^s^shover, and also near Hockley lime-kiln, is silicified and similar
*o the quartz rock found near Bonsall. Cubes of fiuor are
»>umerous on the joint faces of the limestone, and near
VVestedge are veins of the same minerals with slickenside surfaces.
The Crick Inlier. — Crich Stand, which is a tower on the
Summit of a limestone hill, 940 ft. above sea-level, and about
^Deo miles north of Ambergate Station, forms a conspicuous object
^or many miles. On the western face of the hill is a limestone
Quarry containing large blocks of rock piled confusedly one on
Another. The Mountain Limestone has been brought up by three
^^aults and a bending of the strata, and the grit and shales above
^ t have been carried away by denudation. This mass of lime-
stone is about a mile and a-half in length, and about twice as
^road at its N.W. end as at its S.E. It consists of an elongated
^3onie, the main axis of which runs N.N.W. and S.S.E. On the
^^ast the beds dip gently under the Yoredale shales, but on the
^^rest are more highly inclined and bounded by a fault.

Fig. 2 is a section through Crich Hill from west to east.
"The toadstone intercalated with the Mountain Limestone is not
"^-narked on the section. The southern Crich fault has been
traced from near Cromford by Lea Hurst and Coddington Park.

176

H. H. ARNOLD BEMROSE ON

Fault

It brings the Mountain Limestone of Crich Hill against the
Chatsworth grit of Coddington Park. Evidences of this fault are
seen in the small cutting through which the tram-line runs
from Ambergate to Cliff quarry. The line proceeds along the
base of an escarpment of Kinder Scout grit, which is now being
quarried, and just before
reaching the village the
grit is seen to dip W.
and N.W., whilst a short
distance further, in an old
quarry near the main
road through the vil-
lage, the limestone dips
nearly N.

The western Crich
fault bounds the lime-
stone on the west of the
inlier, and passes be-
tween the hill and the
Kinder Scout grit of
VVakebridge Farm. The
limestones here are lower
beds and abut against
the shales, and the latter
are to i)e seen dipping
west at an angle of 60
degrees in the bank of
the small stream near
Wakebridge, a short dis-
tance from the old engine
house.

The Trinity Chapel
fault has been traced
from near Ashover.
through Trinity Chapel
to Culland Wood. It
brings the various mem-
bers of the Millstone Grit
series — viz., the Rough
Rock and the Chats-
worth and Kinder Scout
grits— against the Coal

Measures which lie east of the fault, and the Yoredale beds
which lie above the Crich limestone east of the Stand, against the
Rough Rock and its underlying shales.

The upper beds are cherty, and contain large quantities of
Pfoductus gigantens. They are exposed on the roadside south of
the church in Hill's quarry and in Cliff quarry.

Fault '-■

THE LOWER CVRUOXIFEXOIf riOC tL- f . i?Jt I: — ? : k F_

The following section is given h»y :ne • leoiogirii -jarr^T

I. Thinly bedded .imestones v::n rierr .Tr-j.i „

:. Thickly bedded limestone

3. Waybcoxd of r»lue .-naiv lar

^ \'ery hard nias«ive yrnite .imetii'ir.e

5. Wayboard jI lay ....

6. Limestone

7. T.jadstonc. .iveraifinjf ifjout ... „

^. Limestone, ni wniirn -.ncrf wa^ -.r- -*:: t '^ 'i ■- ■.
Mine, wiihoui reacmnsr TiC -umu.t.

The lower part of bed Xo. 2 s -rnw^iKi ^:r. pr^a^^fi/z \Tui
***^e blocks of limestone almost -^sx-.t^.-: -/>n:r;09efl *: ,v> r^tsji
^''^ seen in Cliff ^nany. Nci. ^ s rCTirisec .1 T^. ..^rry. -.rai c
* Oed of hlai:k shale containny? i few f.os^^is. lu iz^zjtix :*xui
lo^^ear sortaces are tiecomposed :o i lar. azui -r>niiir- r:aai> -i#
^^enite. probably due ro :he :erwn'.ry-Kj:-vn *f rrrxj-s^,
^^[*^^>esof which are pientmii n :tie .ess »irer«i >-^rr.'.-.^ >f -r^
^^^e. The upper surface it ne -nas.^»Te .ni*^friru=-, .*',. ^^
^^•ieriying the shale, :s ^nm ntw urr-iW^ -*rJi --<•. yr: -^rc^.^x vj
^^*^^»e in the limestones b^uw :r*e *:->3ii^.'-.ne .- ^rjr: ,jir-i -,t
. ^ district- The wavnoara >: -.:a\ 'k-.. ' 5 r^ owPi« *^. j»a^
'^ ^e quarry.

A Ia\-a-tiow. contemporaner.-.^ w^tr. r.t^ .r.-,i?r:T/,'-./»', ^ Wrsl

^*^^^e distance lidow :ne ^J>r,7 .:' r.e .^m ir.-: ^ ,m. >rrtn

^^,^e old lead workmi^s. r.ve ai::rir>r ;erj-i-^.r.ef: r^* V,i-^.r:r:^

f^^^^e %ome six year; 3450 'o -::;:ar.-:r.e r^ /rer.u -r*rk- roT, *'-..r^l

^^^^ ore was \ycinz "jniaineo. T.-.e "-»r-: ^ * Vr.-^T.'-^ov^

^'Xxygidaloidai olivine-ioiente :ravrf'rr?x^ ,v -^-.x ->r a4r.r/- -,r.fi

I^^'^t^ning a lanje luannty li tyr.itr^ .': % r.:f^.*r^.^r. »:.. ne

.*^estones. and the gateway >t erei -.a.x.Nrr. hrr/^, r -,-. ,^,Th

Jj^*^5 of the anticline. Near :r*e "^xrr^r.rit t, r^ .i-^ir'- *r,n a*^.:.'^!

^/5^ ^^" ^^ upper cherrv -»eru v,:r. .-.rr.iiv ■*n/'l f^r-'-turtui ve

2^^*^ In the luany are 'cait.ci jaryrf^ u-ij *^>^»r*. .T,ar. •^::e.

- ^^*^te and yellow tinor. uici >f4iail vr-:n^ .r .>s.i>na.

^Hiverai landslips^ ii:e to 'tie %iipp:nz .? r.e ir.-*rr:uf*r.e W*. 2
^^ ^e bedof ihaic. riare vtrzirrpfl :'rr,rn inv .* ;rr..^ ir. rjft -ir*rn-
^-^^^*^ slope of rhe hill. In :iiarrrna[, r.,*: r.ir^r :m/r,u>np. rMf.n
j.;/~*^^^^^^3ied the!owe« part A -he irm vas. 'r^mr.vf*^ '~'r.V5r;-.;ent:y.
j^^^^^ sarts of the Tcid wnir.n ay ■^t:^xx'r r.rt .mtrft if nr-. ifiine,
^ ^^ti^Uj no support and .-esring -m ui nc:inf:n yskv,^. ,: ;ijnper7
,,^^^*^^. ^id down :owards :he -.vtiley o :r»e ir;rr* •vrt^?, md
^^^^*d away part of rJie rracl mrl 1 v.ttacsL The, -.ifer.tf; of
jjjjj *-^st iiip oui uill be seen n -ne -jixarr' »nfl m :he jrr.w ..i" r^e
iiear Cnch Ttand. The ar^ -iif*r;c.. .f .imervir.ne n :ne
"^^ hawe dipped fmm :he iiil-^rte tnr.vp., inrt ;e!wef:n "Me
^ of die quany and the ^nand ne ^oun<i & traveraea ly

178 H. H. ARNOLD BEMROSK ON

chasms or widened joints some yards across, and extending to a
depth of about fifty feet

Kniveion Inlitr, — Between the villages of Bradboume,
Kniveton, and Hognaston, and about four miles north-east of
Ashbourne, is an inlier of Mountain Limestone, the boundary of
which has not been accurately determined, as the ground is often
covered by drift and the beds are very much contorted. The
upper thin limestones are seen near Bradbourne, where they
pass regularly beneath the Yoredale shales, and in an old quarry
east of New House. In the quarry about 30 ft. of limestone with
thin shale partings are seen resting on massive limestone which
dips at an angle of 60 deg. in an easterly direction. Chert bands are
seen in an adjoining quarry, in Standlow Quarry, and east of
Woodeaves Farm. Two faults were seen some years ago in
Standlow Quarry, and are shown in a section given in the Geol.
Survey Memoir, The massive limestones are seen in this quarry
and on Wigber Low. Some of the limestone is dolomitized.
The faulted boundary on the west of the inlier was marked on the
Geological Survey Maps mainly to account for the irregular
behaviour of the toadstone, on the assumption that it was inter-
bedded with the limestone. The four faults form a quadrilateral
figure, consisting mainly of Mountain Limestone with toadstone.
The igneous rock is, however, a coarse agglomerate which cuts
across the limestones, and the faults are therefore not required
to explain its behaviour. Further work is required before it can
be definitely settled whether any one of these faults is necessary
to explain the limestone boundary.

Caverns.

Many of the caverns of Derbyshire are old lead mines, but
others are natural and connected with the underground drainage
of those parts of the district in which they occur. Amongst others
the following caverns are shown to visitors : the Peak Cavern,
Speedwell and Blue John Mines at Castleton, Poole's Hole at
Buxton, and the Cumberland, Jacob's, the Roman, the High Tor,
and the New Key Caverns at Matlock Bath. These, however,
only form a small proportion of the whole. Many parts of the
limestone district are literally honeycombed with them. The hills
south of Castleton from near Mam Tor to Bradwell, and Masson
Hill at Matlock are full of these underground passages.

The existence of unexplored caverns may be inferred by the
lines of swallow-holes found in several parts of the limestone area.
These holes in the limestone vary in depth and diameter, and
have generally the shape of a wide cone with a blunted point at
the bottom. The sloping sides are sometimes steep and generally
covered with grass, with or without any sign of rock. The
swallow-holes are formed by the action of surface water, finding its

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 1 79

way into joints, and enlarging them by dissolving away the rock,
and ultimately emerging at a lower level and at some distance
from the place of entry. As the volume of water increases, the
subterranean course is enlarged by the solvent action of the
water, and caverns are formed, the size of which is often augmented
by the falling in of the roofs, and the partial or complete removal
of the resulting dtbris. Swallow-holes are sometimes found in the
toadstone. When a swallow-hole is formed in the limestone
below a bed of toadstone, the latter falls in and the cavity is lined
-with it. If the toadstone bed is thin, it may be seen resting on
the limestone below it, the two rocks forming the slopes of the
-swallow-hole.

The Speedwell Cavern, near Castleton, may be cited as an

instance of those caverns which are partly natural and partly

.artificial. The entrance is near the bottom of the Winnats. The

-Speedwell level was made last century. It is at a height of about

700 ft. above the sea and 600 ft. below the surface of the hills

"through which it was driven. The object in making it was to

veach some of the rakes which run through the hill. It is said

^hat the total length of the level is about 1,350 yards. At a

-distance of 750 yards the level reached the New Rake which was

Cound to have been hollowed out into a large swallow-hole or

narrow cavern, extending a long distance upwards and to a great

-depth downwards. It is estimated that 40,000 tons of rubbish

^om the driving was thrown into this chasm, now called the

•' bottomless pit," without any visible effect.

In Mill Close Mine, near Darley Dale, caverns are found along

-'^)r branching off the main vein. They sometimes attain a great

size, and several are often connected together. Many of these

large cavaties are rich in ore and lined with dog-tooth spar and

'C:ubes of galena.

The Blue John Mine is another instance of large underground

• ^^zavities connected by artificial passages. It is supposed to have

fceen discovered accidentally in some mining operations by the

Romans. It is situated in Treak or Tray Cliif, near Windy Knoll

^and the top of the Winnats south of Castleton. The northern

SX)rtion of the main mass of Mountain Limestone is here cut off

Ifrom the Yoredale shales by faults on the north, west, and east.

This cavern was carefuMy examined by Messrs. Barnes and

Xlolroyd, and the following brief particulars are taken from their

description : The entrance to the mine is by means of an

-^irtificial opening, which soon leads to a natural passage 28 ft. in

height. The mine consists of a series of natural passages and

^-•czaverns connected by artificial passages. These cavities are

Xcnown by various names. A swallow-hole, 49 ft. deep, with

numerous pendant stalactites, is passed through. The level

path called the Ladies' Walk leads to the (irand Crystallized Cavern,

^%vhich is 60 ft. long, 13 ft. wide, and 45 ft. high. Lord

l8o H. H. ARNOLD BEMROSE ON

Mulgrave's dining-room, 39 ft. by 36 ft. and 57 ft. high, is in the
form of a rhomboid in vertical section. The tioor is artificial, the
real bottom being far below. Underneath the floor is a stream
of water. The walls of the Variegated Cavern are lined with dog-
tooth spar. In the two latter caverns are many large blocks of
limestone which have fallen from the roof. The New Cavern is
100 yds. long and 16 yds. wide, and is described as the "largest,
the wettest, the dirtiest, and the most rugged and irregular " of
any of the series. This cavern leads to the Fairy Grotto, a small
cavity 17 ft. by 13 ft. and 20 ft. high, with sparkling carbonate of
lime covering the walls and floor and forming delicate stalactites
and stalagmites. The distance from the entrance to the Varie-
gated Cavern is 300 yds., and the vertical descent 220 ft. The
total distance of the winding passages is said to amount to over
three miles. Some curious curved and upturned forms of stalactites
were found and called by the authors anemolites. They were
considered to be due to currents of air blowing the water to one
side or in an upward direction, and causing more rapid evapora-
tion and deposition of carbonate of lime on one side than on the
other. Blue John is a banded variety of coloured fluor-spar, and
is largely worked into ornaments. It occurs in veins, nests, and
fissures, and as nodules in the limestone. Barytes and calcite
are associated with it.

The Peak Cavern at Castleton, the entrance to which is by far
the finest part, is another good example of a natural cavern
connected with a system of underground drainage. This
cavern drains the district immediately west and south-west
of the village. The water enters the limestone along a line
of swallow-holes from Perryfoot to Windy Knoll, near the
boundary of the Mountain Limestone and Yoredale Shales. At
Perryfoot a small stream disappears down a hole in the limestone.
The course of the underground water was identified more than a
hundred years ago. It is seen in the Speedwell level running
east, and finally discharges partly through the cavern, but largely
by a spring near its mouth called Russet Well, and flows down
the valley, joining the river Noe near Hope. Part of the water is
probably derived from the hills further south. Eldon Hole, a
chasm near Peak Forest village, may also communicate with the
cavern. It is reported that a goose which fell down Eldon Hole
emerged at Castleton.

Another system of underground drainage occurs near Eyam.
The water enters by swallow- holes, notably by one formed at the
intersection of two veins near Foolow, and finds its way to the
valley of the Derwent by way of Middleton Dale. The dis-
appearance of the water often results in a dry valley which
represents the old watercourse. Linen Dale, near Eyam, is one
of these valleys. Great Rocks Dale, through which the Midland
Railway passes between Miller's Dale and Doveholes, is another

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lS2 H. H. ARNOLD BEMROSE ON

of 2 ft. Apparently it once extended further in the direction
towards Matlock Bridge, since the eastern wall of the fissure
produced, forms the face of the present cliff which bounds the
valley. A diagram sketch of this fissure is found in the GeoL
Survey Memoir, on p. loi. The Roman Cavern consists of a
smaller fissure, which runs nearly parallel to the strike and to the
boundary between the limestone of the High Tor, and the
Yoredales and grits of Riber Hill.

Lead and Lead Mining.

The Odin Mine near Castleton is probably the oldest in the
county and is reputed to have been worked by the Danes. The
discovery of pigs of lead with Latin inscriptions proves that lead
ore was raised and smelted in Derbyshire during the Roman
occupation. The mines at first appear to have belonged to
religious houses and eventually passed into the hands of the
Crown. Curious customs and rights connected with the mining
of lead have been in use from time immemorial, and these were
confirmed to the miners by two Acts of Parliament passed in
1 85 1 and 1852. The following short quotations from Mr.
Stokes' exhaustive paper on the early history of lead mining in
Derbyshire will give some idea of these customs : ** All subjects
of the realm may search or dig for lead ore in or under any
person's land (without even asking permission of the owner of
the surface), and providing the miner finds ore and frees the
mine by paying one dish to the Barmaster. He then claims and
is entitled to sufficient surface or land for his hillock or spoil
heap, a way for foot-passengers or carts from the highway lying
most convenient to the mine, and also waterway to the nearest
running stream of water. The owner or occupier of the land
over which these things exist cannot claim any compensation."
"The only compensation the landowner gets for all this
annoyance and loss of surface is the right to sell and dispose of
all and every other mineral raised by the miner except lead ore."

Dues were paid to the Crown, the Duchy of Lancaster, the
Barmaster, and in some places to the Church of the district. The
royalty to the Crown was so much per dish, a dish containing
about 472 cubic inches. The tithe which was often disputed
** is said to have arisen from the assertion that the ore grew and
renewed in the vein."

The lead ore which has been mostly worked is known as galena
or sulphide of lead. It contains a small quantity of silver (two
to four ounces per ton). Cerussite or carbonate of lead, called also
white ore, is found in crystals lining cavities in galena, and is
supposed to be an alteration or decomposition of the sulphide.
Mimetite (brown lead ore), pyromorphite (green lead ore), and

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 183

phosgenite (yellow lead ore) are also found in small quantities,
but the latter two only as cabinet specimens.

The ore occurs in Rakes, Pipes, and Flats. A rake vein is
generally an almost vertical fissure or crack in the limestone.
\Mien the fissure is due to a fault the walls often have a
slickenside surface and the beds on either side of it have suffered
displacement Serins are strings of ore which branch off from
the rake and form smaller veins. The ore occurs in ribs with
layers of calcite, barytes, or fluor arranged more or less parallel to
the walls of the rake. Sometimes it is found in isolated cubes or
assemblages of cubes of galena with calcite or barytes.

Pipe veins are irregularly shaped cavities or pockets in the

limestone generally parallel to the bedding planes, and often

cx>nnected with one another by a crack filled with clay or spar,

csdled a leader. They vary considerably in size, and may be

cronsidered as the widening out of a rake or serin. The ore in

tiiera is often found in lumps mixed with blocks of limestone,

iDarytes, calc spar, and clay. This mixture is apparently due

^o the falling in of the roof of a cavern lined with these minerals.

A Flat is not so common as the rake and pipe veins. It is

generally found along the junction of two beds, and consists of a

^ow flat chamber with the roof and floor only a few feet apart, and

^seldom has any leaders connected with it

' The lodes are richer and more numerous in the upper than in

^he lower beds of limestone, and most of the rich deposits of ore

^^lave been found in the beds immediately below the Yoredale

shales. It has often been stated that the toadstones are un-

:K^i'oductive of ore, and it was contended that the vein was cut of!

^r^y the igneous rock, and therefore that the latter had been

^M. ntruded between the limestone beds after the vein was formed.

^S'n some cases a vein on entering the loadstone becomes broken

'^jip into a number of strings of spar, or changed into a thin leader

^^i^f calcite. But the ore was undoubtedly worked in the toadstone

^^^ XI the Seven Rakes Mine, near Matlock, and in the Wakebridge

^^^line, near Crich, The author visited the workings of the latter

y^jnine, and saw some fine cubes of galena in the toadstone.

^ -though some of the toadstones are contemporaneous with the

^ :imestone, others are intrusive and later than the beds in which

"^^Jhey occur. The intrusive sheets and vents if later than the

^f^ormation of the veins would undoubtedly cut them ofi".

The large number of old lead mines bears witness to the great
^^mount of mining which has been done in Derbyshire. But of
^-5ite years only few mines have been worked. The majority have
^::::^een worked out or abandoned because of the incapacity of the
^^wner to continue through the difficulty of getting rid of water or
^lie expense of obtaining the ore, and not least because of the con-
siderable fall in the price of lead. The Wakebridge workings were
^^ntinued until a few years ago, and ore has lately been obtained

184 H. H. ARNOLD BEMROSE ON

near the surface at Monyash. But the only mine at which lead is
being raised at the present day is the Mill Close, near Darley Dale.
It was abandoned for 100 years and re-opened in 1859 by the
late Mr. Wass. Since then a large quantity of ore has been
obtained. It is in the upper beds of the Mountain Limestone.

Small quantities of copper ore, black oxide of manganese
(commonly known as wad), haematite, yellow and red ochre, have
been worked in the limestone ; heavy spar or caulk (barytes), used
in the manufacture of white paint, has of late years been obtained
in the old hillocks. A stalactitic form of barytes was found near
Youlgreave.

Fluor-spar (calcium fluoride) is found in small cubes lining
fissures in the limestone, and has been worked at Ashover.
" Blue John," the purple variety arranged in layers of different
shades of colour, is found at Castleton. Calc-spar is abundant in
veins, and is crushed and used for making footpaths. Bitumen is
found only in small quantities and in two forms. The brittle
variety may often be seen filling small cavities in the limestone
and the interior of fossils. It is black and hard, and has a shining
surface when fractured. The softer variety known as elaterite is
elastic and adheres to the fingers, but is sometimes soft like
indiarubber. It is black and dark brown. Both kinds occur in
Windy Knoll quarry, near Castleton, The following analysis
of the elastic variety from Derbyshire was made by Prof.
Macadam :

Carbon 83-634

Hydrogen Ii'i86

Oxygen, &c 4781

Nitrogen 0172

Sulphur 0*237

100*000

Metamorphic Limestones.
Contact metamorphism, due to the intrusion of igneous
rock, is seen in some of the limestones in contact with the sills.
The limestone above the sill at Peak Forest is rendered
saccharoidal to a distance of 5 ft. from the junction, whilst
that below the sill in Tideswell Dale has been altered to a
distance of 1 2 ft., and a clay has been baked to a distance of
9 ft. from the junction. The saccharoidal or marmorised lime-
stone is easily distinguished from the ordinary more or less
crystalline variety of limestone with fossils which is found in many
localities. When completely marmorised, it is crystalline, hard
and brittle, and breaks with a powdery and saccharoidal fracture,
and all traces of fossils are often obliterated. Pieces of marmorised
limestone are found in the agglomerate of necks. This meta-
morphism cannot always be traced in the neighbourhood
of the intrusive rocks. Some of the sills and necks, although
they show undoubted traces of cutting across the beds, have not

ife^ it be ac tfts: mtiudL janctfioni. whkh is hjbi&ko Crom
Emai inifleneiJi&bQiic&aQdQfchetwoIiugei^^
m. t&e IJhnfHUflngy chacmi^ tu some ei]:eat cnnstallrQie^ camtot be
said ao ht mvmtwmHit^ mak vaarf at the small rounded luoap« of
PTiuiiieieiuime Smas^ m. t&e agggibmeEate of vents ind tn bedded ttuti^
aie 083QC' liifac (jjonnoscir r^ m i^**^'}^^^

DofioimiesBEii Iimie»txaae (IbciII^ known as Dunstone) is tound

m mamw pHtis of t&e cfiatrax biz£ appears to be mainly confined

10 the iMJijehniLL pactooo. Some of the beds axe almost pure

4nflnBBtoy mad m. t£aai e£ie oc^^anic structonr* if ever pnesent. b.fts

been csBCnrdlf ob&ecaQed. It forms thi<± beds on Masson HilL

^vincli aie veBE eiposed cut the bSl dopes and in the CumberUnd

Caiem at Macteri ftich. Near Hopton and Brassington^ along

tbe coQae of ti&e Higb Pesik Railway » it cs apparently present as

a bed OB eiic Moontain LioiestOQe* the thickness of vhtch has

been f<iiina8wl bj dbe Geological Surrey oli&cers at 400 ft. It

'vextiieis iotto ra;tfrlliatrrf ootlines, soch as those at Harbro' Rocks

sod aloog tfae iSopes of the valley leading from Longdiffe Wharfe

'to Bfadboome MSL and presents a marked contrast to the white

limestone ci die ^stxicL It has a rough and often knotted

^weadienng ; the scufiKe is fircquently pitted with small hole$> and

some specimens cootatn boUcw moulds of encnnile stems. It is

^so found north of Grange Mill : and in the neighbi>urhiX»d of

^Vinster crosses Gratton Dale, where it is interbedded with the

limestone, dipping N. at an angle of 20 deg^ and attains a thick>

9iess of about 450 ft. Below the thick bed in this Dale, and

separated from it by about 20 ft. of ordinary limestone* is another

^olomitic limestone, the whole thickness of which is not Wsible.

^t is probable that these two almost parallel outcn^ps of

^dolomitized limestone once formed parts of the same l>ed in the

*^ome of limestone of which Grange Mill is the centre. Both

%eds are about the same depth down in the series. The Hopton

^)ed, according to the Geological Survey Section, is more than

<oo ft. below the top of the Xfountain Limestone, and according

^^o the author's measurements, the Gratton Dale l)ed is 700 ft.

^^low the limestone boundary at the bottom of Gratton Dale.

The dolomitized hmestone also occurs on a much smaller

^scale. Sometimes the dolomitisation has proceeded along joints

^n the limestone; at others part of a bed is altered, and the

^^emainder consists of ordinary limestone. When weathered* the

dolomitized limestone has a rough, gritty surface, and decomposes

'into a soft gritty sand, which may he seen in some new workings

^tween Longcliffe and Grange Mill. Some of the thin

dolomitized limestones, especially those occurring in the Voredale

shales, might easily be mistaken for sandstones on the weathered

surfiace.

Silicified Limestone or Quartz Rock is found in blocks on the

l86 H. H. ARNOLD BEMROSE ON

surface of the ground at Batham Gate, Brock Tor, and Oxlow
Rake, near Tideswell, and in other localities. At the head of
Pindale, these blocks are large and numerous, and sometimes
contain small quantities of chert. The rock occurs in irregularly
shaped bosses on Masson Hill, near Matlock (see Map, Plate III),
and at Ashover. Its microscopical composition and its relation
to the limestone beds show that it is a limestone which has been
entirely converted into crystalline silica. It consists of quartz
crystals, often elongated and interpenetrating one another, forming
an aggregate of quartz grains. It is not formed of detrital grains
cemented together by secondary quartz, but has originated by
the crystallisation of the quartz in such a manner that adjacent
grains have prevented their neighbours from assuming crystalline
boundaries. It frequently contains flupr ; associated with it is a
quartzose limestone, /.^., a foraminiferal, and sometimes an
oolitic limestone, containing a large proportion of quartz in
individual crystals and bunches of crystals, like very minute
portions of the quartz rock. Small veins of similar structure also
traverse the quartzose limestone, and the latter is often found
in small lumps inside the completely silicified rock. There is a
gradual passage from the quartz rock through the quartzose
limestone to an ordinary limestone, which contains few, if any,
crystals of quartz. This mineral, therefore, is present in some
parts of the limestone as numerous separate crystals, in groups of
crystals, and on a larger scale as veins and bosses of quartz rock,
and a common origin must be ascribed to the quartz in the
quartzose limestone and in the quartz rock. The presence of
chert in the quartz rock of Pindale and part of a foraminifer in the
similar rock of Pounder Lane, and the frequent penetration of
organisms by quartz crystals in the quartzose limestone appear to
be sufficient evidence of the quartz rock being a replacement of
limestone. In cases such as at Top Lift the whole of the limestone
and quartzose limestone have been weathered away, leaving the
quartz rock in bosses or loose blocks. In others, patches of the
softer rocks are left which show the transition from an ordinary
limestone to a completely silicified rock.

Yoredale Rocks.

The Yoredale rocks of the Geological Survey include the
sandstones, shales and limestones which lie between the lowest
Millstone Grit and the Mountain Limestone. They were
originally divided into the following three groups, and are mapped
as such on the i-inch Geological Map:

Upper Yoredales. Yoredale or Shale Grit, with shafle and thin
sandstones above and below.

Middle Yoredales. Yoredale s;\ndstones, with beds of black
shale.

Lower Yoredales, Black shales, with thin beds and nodules of
earthy limestone.

Proc. HhjOL. Assoc., Vot

Map <»r District N.E.

Jifaantaiit Limestone
^ucut^ Rock.
2u4zrbfOse Limestct

-^^ff! .r

To fact A»A< '•'*' i

THE LOWER CARBONIFEROUS ROCKS OV DERBYSHIRE. 187

It was found that io Derbyshire there was a lithological
difference between the Kinder Scout and Yoredale Grit, but that
further north these distinctions vanished. The classification was
therefore modified, and in the second edition of the Memoir the
Yoredale Grit was transferred to the Millstone Grit group. At
the same time the term Yoredale Grit was abandoned and Shale
Grit was substituted for it. So that the Yoredale rocks at
present consist of two divisions, viz,, the sandstones with shales
and the shales with limestones. This classification was con-
sidered to be provisional^ and one convenient to be retained.
The Yoredale sandstones were looked upon as "passage beds
deposited irregularly in the interval during which the change
took place from the marine conditions of the Carboniferous
Limestone series to the freshwater or estuarine condition of the
Millstone Grit and Coal Measures.'' Lithological characters were
the only guide since no fossils had been found in the Yoredale
Sandstones. The difficulty of drawing a line between these
sandstones and the shales and limestones below them was
pointed out. There seems to have been a doubt whether the
Yoredale sandstones mapped in Edale and about Bamford are
the equivalent of the Yoredale sandstones of N. Staffordshire, or
-whether they ought to be included in the Shale Grit. South of
Hathersage the thin limestones and shales are generally found
immediately below the Shale Grit.

Dr. Wheelton Hind considers that the Yoredale rocks of
AVensley Dale are the equivalent of the upper part of the Car-
boniferous Limestone, and that the Yoredale beds of Derbyshire
are a different series and occupy a position above the Carboniferous
Limestone. He proposes to divide the Carboniferous rocks into an
upper and lower series, the upper one to include the Coal Measures
and the grits and shales below them, the base being drawn at the
uppermost thin limestone. The lower group to include the
shales with thin limestones and the Mountain Limestone. He
^ould restrict the term Yoredale series to the district of Wensley
Dale. He claims that this binary division is based solely on
biological grounds. It appears then that Dr. Hind draws the
boundary between the Upper and Lower Carboniferous rocks at the
base instead of at the top of the Upper Yoredales. If we con-
sider the Yoredale sandstones of the Geological Survey to belong
to the Millstone Grit series (which in the case of Derbyshire the
writers of the memoir seem to think is probably the correct view) the
"Yoredale rocks of Derbyshire will then include only the lime-
stones and shales which lie above the Mountain Limestone. Dr.
Hmd's boundary and that of the Geological Survey thus practically
become one and the same for Derbyshire, and the only point in
tlispute appears to the author to be the use of the word Yoredale.
"Whatever may be the ultimate fate of the term, the author has
as a matter of convenience followed the nomenclature of the

[88 H. H. ARNOLD BEMROSK ON

Geological Survey and retained the use of the word in this
Sketch.

The black shales and thin limestones of the lowest division
of the Yoredale Rocks vary in character and thickness in different
parts of the county. In Edale they consist of shales with
nodules of limestone containing Goniatites, At Cromford, the
limestone forms short lenticular beds in the shale. In other
places the limestone is in thin beds intercalated amongst the
shales, and the proportion of limestone to shale varies greatly.
About 36 ft. of alternating limestone and shales in the railway
cutting at the east end of Monsal Dale were recorded by the
Geological Survey. They rest on the cherty beds of the Moun-
tain Limestone. The thin limestones amount to a little over one
quarter of the whole, the remaining three-quarters consisting of
shale. Near Ashbourne, the limestones are evenly bedded,
become more numerous, and closer together, so that it is often
difficult to say whether they should be placed at the base of the
Yoredales or at the top of the Mountain Limestone. They often
contain chert, encrinites and ProductuSy and are frequently
dolomitized, and cannot be distinguished petrographically from
some parts of the Mountain Limestone. These beds are seen in
the neighbourhood of Kniveton, and in nearly every case are
contorted. But perhaps the best exposures, which give evidence
of the numerous folds into which these beds have been thrown,
have been laid open recently in the construction of the new
L. & N. W. Ry. from Buxton to Ashbourne. In the cutting in
which Tissington Station is situated, the shales and limestones
are seen to have been bent into about six anticlines, and the same
number of synclines in a distance of 300 yards, and only about
90 ft. of shales and limestones are seen. Though several lime-
stones have been traced through this part of the cutting, others
are very inconstant and soon thin out. They contain chert
bands, Productus^ encrinite stems and fish teeth. Some are
dolomitized, others are black and similar to the upper beds of the
Mountain Limestone. Plate IV, Fig. 2, gives some idea of the
contorted strata seen in the cuttings. Further reference to these
beds will be found in the remarks on the igneous rocks.

No reliable estimate of the thickness of the Lower Yoredale
shales has l)een formed, because the beds roll about so much,
especially in the north and south-western part of the district.
Between Eyam and Matlock several lead-mining shafts have been
sunk through them, and proved that they are at least from 300 to
400 ft. thick. According to the Geological Survey the two
groups forming the Yoredale series are at least 400 or 500 ft.
thick, and may reach even t,ooo ft. Very little information
seems to have been obtained about the Yoredale sandstones
which form the upper group. It has already been stated that the
sandstones in Edale, which are mapped as Yoredale, may

Proc. Geol. Assoc., Vol. XVI.

Plate IV.

Fig. I. -Basalt Agglomf.rate, in Volcanic Vent, Hopton,

NEAR WiRKSVVORTH.

■

r^^M

^^^^^^^B

i^^dMifli

^^^^H^ 'w ^^^^^^^^^^^1

^^^^K!^r

^^^^^K"

1 ' '^'iU

♦-•ft* ■'

^^^■^

Fig. 2.— Syxclinb and Anticline in Voredale Shales and Limestones.

L. & N. W. Rly. Cutting, Tissington, near Ashbourne.

{From Phot0^ra/>hs by H, AntoU'Bemroit)\

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 1 89

possibly belong to the Shale Grit. In places farther south they
are absent altogether, the Shale Grit resting on the Yoredale
limestones and shales.

Millstone Grit.

The Millstone Grit series of Derbyshire consists of five thick
sandstones parted by shales with which thinner sandstones are
interbedded. These grits vary in character from a fine-grained
sandstone to a conglomerate, and consist mainly of quartz, ortho-
clase-felspar and mica (muscovite). According to Dr Sorby, they
have been derived from the disintegration of older rocks, such as
granite and schist, and have been deposited by currents from the
north-east. Traces of coal are found on the top of each of the
five sandstones.

The Fifth, or Shale Grit, so called by Farey because of the
intercalated shales it contains, consists of thick massive sand-
stones, hard and close-grained, passing often into a conglomerate.
The intercalated shales are inconstant and when traced some
distance are found to die out, and others to make their appear-
ance. It attains a thickness of 500 or 600 ft around the Peak,
thinning away to the south and being absent in some places.
Round the Kinder Scout grit of the Peak, the Shale Grit forms a
broad plateau which is deeply channelled by rivers and brook
courses. The outcrops of the shale bands are marked by small
terraces which run along the steep sides of the valleys. Along
the course of the River Alport are numerous landslips, the
largest of which is called Alport Towers, formed by masses of the
Shale Grit which have slid down from the hills above. South of
the Peak the Shale Grit caps the ridge between Lose Hill and
Mam Tor. The beds dip north, and farther south, at Castleton,
we come to the Mountain Limestone. The River Noe, which
runs down the Edale valley, has cut down into the plateau of
Shale Grit to the Yoredale Limestones. The arrangement of
the beds is shown in Fig. 3, which is a section across Edale
and the Castleton Valley, from the Geological Survey Memoir,
An anticline ranges along the north flank of the valley and on the
north side the Yoredale rocks are brought out by the southerly
rise of the beds. Some good sections are given in the " doughs "
which run down from Kinder Scout into Edale. The following
is an average section by the Geological Survey :

ft.
Millstone i Sandy Shale below the Kinder Scout Grit ... 290

Grit. | Shale Grit 425

( Supposed representatives of the Yoredale

Yoredale J Sandstones 200

Rocks. | Black Shales and nodules and beds of

( Earthy Limestone —

On the south flank of the valley there are few sections, except
along the river Noe. At right angles to this anticline another

190

H. H. ARNOLD BEMROSE ON

Grindtlow Knol •

Edale. R. Not.

Mam Tor

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 19I

one runs throned Edale Chapel and Mam Tor in a N.W, and
S. El. direction. If produced it passes through the middle of the
^■m^stone district; and it has been considered to mark the direction
of rtie Pennine upheaval A dome-shaped mass of the Lower
Voredale beds is brought up in the middle of the valley, and
^^ "Yoredale sandstones of Mam Tor are raised higher than the
Sha.lc Grit of Lose Hill.

Xn the scarped face of Mam Tor, about 200 ft. of what are
por^sidered to be Yoredale sandstones are seen. In the shales
*?^^«-calated with them Dr. Wheelton Hind found Goniatites and
-^^'^hniella. At the foot of the Tor the lowest division of the
^oi-^<jale rocks are found to rear up on end, and are faulted
?jSa.inst the Mountain Limestone near the Blue John mine.
^^*^ Tor is called the shivering mountain, owing to landslips
^^*^^^h have taken place. A great part of the hill has fallen, and
^^^*"ried away with it a portion of a Roman entrenchment

^ TThe Fourth, or Kinder Scout Grit, consists of two thick beds
^ ^^ndstone separated by shale. The lower one — a coarse grit
^^^ conglomerate-— dies away on Bamford Edge, and is not
^*^^ further south. The upper one varies from a coarse grit to
. *Jne grained sandstone The Kinder Scout grit generally forms
f^^ craggy cliffs surmounted with piles of rock weathered into
^^^^stic shapes. Robin Hood's Stride and the Rowtor rocks,
y^^^t" Rowsley, are formed of this grit. The Black Rocks is the
^^'^^e given to an escarpment of the Fourth grit near Cromford,

^^^^ the base of which the High Peak Railway runs.
g ^Ir. Mello considers that the " bosses of rock and tabulated

j^^^'^^s," near Edale, " have a wonderfully close resemblance to
^^^' 3hore rocks," and that the inland cliffs of the Black Rocks
j^^ Kinder Scout are outliers of grit which have "escaped
^1^**^^ carried away by the wear and tear of the sea," and that
^ ^ bold cliffs of Kinder "still bear in the rock basins and
^l^*^CDwed faces so frequently present marks of that time when
^«^^ salt waves dashed against it and wore it into its present

^^ It appears more likely that these results are due to the effects
^1 ^Xibaerial denudation. The grit is underlain by shales, and
s|^^^ into the hill near Cromford and at Kinder. As the softer
j^J^^J^^s are removed the grit falls down in blocks and an escarp-
ji^^^>t is formed. The undercutting of the bosses of rock, such
^^^^-^e found on Kinder, were considered by Sir A. Ramsay to be
^^^^ to the denuding action of loose sand (produced from the
i^Z^^hering of the grit) being blown by high winds against the

^^ted bosses of rock.

tw The Third or Chatsworth Grit varies greatly in character. In

^^^ centre of the district it is a coarse conglomerate, and be-

j^ ^>es a fine-grained sandstone as it is traced north and south.

^^ often called the Escarpment grit. The broken edge of its

192 H. H. ARNOLD BEMROSE ON

outcrop forms long escarpments, which often run for miles along
the country and make a distinctive feature.

The beds between the Third and First Grits are very change-
able, and made up of shales with sandstones which vary in
thickness and horizontal extent, beds of gannister, and thin
coals.

The First or topmost Grit is known as the Rough Rock, and is
the most constant of the series in thickness and character. It is
described as a massive coarse grit with a large proportion of felspar,
the decomposition of which makes the rock loose and crumbly.
Its average thickness is 100 ft.

The terraces or escarpments formed by the various grits are
seen along the line of Horizontal Section, No. 69, of the
Geological Survey. The entire series is crossed from the Lower
Coal Measures on Ughill Moors to Derwent Chapel.

Miscellaneous.
Sands and Fire Clays in the Mountain Limestone.

Deposits of coloured sand and clay, with quartzite pebbles,
occur in pockets or irregular hollows in the limestone in the
neighbourhood of Newhaven and Brassington. They are situate
on a line running in a direction from N.W. to S.E. for a distance
of about seven miles from near Hartington, on the N.W., to
Brassington, on the S.E. In addition to smaller pits, larger ones
have been worked at Newhaven, Minninglow, Longcliffe, Harbro,
and Brassington. The clay from the latter place was worked
previous to 1789, and sent to Derby Porcelain Works. These
hollows in the limestone, which may represent swallow-holes,
reach as much as 100 yards across. The deposits consist of a
very fine clay and clean sand, the lines of division between them
often being nearly vertical. The sand is sometimes bedded in
the form of a basin, that in the centre of the pit being nearly
horizontal, and that near the edges dipping steeply away from the
limestone which forms the sides. At Newhaven and Longcliffe,
the removal of the sand and clay has brought to view the
weathered upper surface of the limestone, which forms part of
the walls of the pit. The clay and sand are sometimes white,
and at others coloured red and yellow. The sand contains
many quartzite pebbles, which are generally white, but sometimes
red.

Various explanations of the origin of these deposits have
been given. The presence of quartz pebbles was considered by
the Geological Survey officers to denote that a portion at least
was derived from the Kinder Scout grit, and it was supposed by
them that a large part of the material was due to the decomposi-

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 1 93

t^xi of chert and sandy or argillaceous limestone, and that the
IsoUows, as in the case of the similar Welsh deposits, were filled
in pre-Gladal times. The origin of the sands and pebbles has
adso been attributed to the Bunter Beds. However much
opinions may differ about the origin of the deposits, there is no
doubt that they are pre-Glacial. Mr. Deeley and the author
liave found undoubted proof of this in the case of one of the
pits.

An examination of the sand shows that it consists of small,
^«rell-rounded grains of quartz, unlike the angular grains found
i n the Kinder Scout grit If, therefore, it has been formed from
^hat rock, it must have been subjected to such an amount of
trituration as would convert the angular into rounded grains.
The author found lately, in one of the hollows near Brassington,
^ piece of reddish-coloured grit, with quartz pebbles imbedded in
m t. Without microscopic examination it is unsafe to say whether
mt is from a bed of Millstone Grit or a portion of the sand solidified
<^nd hardened in situ.

Glacial Drift.

The drift deposits of the lowlands of Derbyshire have been

*^ully worked out by Mr. R. M. Deeley, but very little has been

^done at those in the hill district included in this Sketch. Mr.

IX)eeley is extending his researches to this part of the county, but

Knas not yet published any results. The following is a very

^■r>rief summary of what has been observed by the Geological

-^Survey and by the author. Deposits of clay containing striated

^■.imestone boulders, large pebbles of grit, and a few boulders of

^iK^oreign rocks are found in the valley of the Wye, at Monsal Dale,

IK^ongstone, Baslow, Haddon Hall, and Youlgreave, and on the

:^flanks of the Derwent Valley near Matlock and Crich. Thick

-^deposits of Boulder Clay were found in the five cuttings in the

^M^. & N. W. Railway between Ashbourne and Tissington. The

"^c^lay contained numerous boulders of well-striated Mountain

^X^imestone, of grit, sandstone, shales, chert, and igneous rocks

^•^oreign to the county. At Spital Hill, a short distance south of

^«-\shb3urne, a well boring passed through 50 ft. of clay with large

^S. imestone boulders, and 20 ft. of running sand.

Pleistocene Mammalia.

Many Pleistocene Mammalia have been discovered in caverns

^^nd fissures in the Mountain Limestone. Elephant remains were

^"ound at Balleye, near Wirksworth, and in a fissure at Doveholes,

^nd a rhinoceros tooth was found at the entrance of Peak

^lilavem. In a cave near Matlock, rhinoceros, cave hyaena, bear,

^^^ndeer, fox, red deer, and bison were discovered, and in Harth

194 I'HE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE.

Dale remains of rhinoceros, bison, and mammoth. At Windy
Knoll, near Castleton, bones of bison and reindeer, with grizzly
bear, wolf, fox, hare, rabbit, and water vole, were obtained by
Mr. Rooke Pennington from a swallow-hole in the Mountain Lime-
stone. A cavern in Cave Dale contained bones of recent ^auna,
as well as relics of human occupation.

Calcareous Tufa and Stalactitic Deposits.

These deposits are due to the solvent action of water charged
with carbonic acid on the limestone. As the water evaporates,
the carbonate of lime which has been dissolved is re-deposited as
beds of tufa, and in a cavern the drippings from the roof form
stalactites and stalagmites. The tufa consists of amorphous
carbonate of lime, which has often been deposited around twigs,
leaves, moss, shells, and bones of animals. Large deposits of
this rock have been formed by the warm springs at Matlock.
Above the right bank of the Derwent it reaches a thickness of
30 ft., and is at the present time well exposed near the New Bath
Hotel, which is built upon it. At Matlock, and in the Via
Gellia, it is quarried for ornamental rock-work, and has been used
in the construction of a house in the latter valley. That some
parts at least are of recent origin is shown by the finding
imbedded in it a Roman or Saxon iron spearhead by Mr. Mello.
Proofs that it is being formed at the present day also are numerous
at Matlock and in many parts of the limestone district. Two of
these only need be mentioned. On the southern slope of Miller's
Dale a spring issuing from the top of the toadstone bed has
covered the face of the dark-coloured igneous rock with a thick
crust of tufa, and in Monk's Dale a stream is forming small
terraces of tufa with basins like the New Zealand sinter terraces
on a small scale. The petrifying springs at Matlock Bath which
issue from the limestone form deposits of calcium carbonate on
the small objects placed in them, and along their short course
into the river are forming tufa.

Warm Springs.

Owing to the readiness with which the surface waters make
their way down into the limestone it is not surprising to find that
many parts of the area covered by this rock are destitute of water.
Were it not for the beds of toadstone and the clay partings
which are impermeable to water there would be no springs on the
limestone hills at any height. Many of the springs issue from
the top of a tos^dstone bed, the upper surface of which may often
be traced at points along the line of its outcrop. Several springs
flow from the top of the bedded ash near Grange Mill.
Dunsley spring, which ^ns down into the Via Gellia, Five Wells

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 1 95

and Other springs near Taddington flow from the upper surface
of toadstone beds, and according to Dr. Darwin, one of the
lilatlock springs issued from cracks in the upper surface of a
bed of toadstone.

Many of the springs are warm, or at least tepid. The most
noted are at Buxton, Matlock, and Bakewell. Those at
]Buxton are supposed to have been used by the Romans. The
eemperature of St. Ann's Well is 8i deg. F. The water has been
frequently analysed, and is remarkable for the amount of free
nitrogen dissolved in it It was found to deposit a hydrated
peroxide of manganese on the walls of the bath. Another spring
supplies the tepid swimming bath.

The temperature of the warm springs at Matlock Bath is
^8 deg. F. They supply the Fountain swimming bath, and
smaller baths at the New Bath and Royal Hotels. An analysis
C3f the spring at the Fountain baths was made by Dr. Duprd.
Xt contains

Grains
per gallon.

Chloride of Sodium 4*57

Sulphate of Magnesium 973

Sulphate of Calcium 204

Carbonate of Calcium 14*68

Silica ... ... ... ... ... ... ••• 0*71

Total 3173

Organic matter, traces of alumina, minute traces of

poussium, lithium and strontium and loss 1-03

Total dry residue 3276

^^-nd a small quantity of free carbonic acid.

^^^^ The old swimming bath at Bakewell is supplied by a spring at

^^ temperature of about 60 deg.

Igneous Rocks.

The igneous rocks of Derbyshire are locally known as Toad-
clones. The word is derived either from the supposed re-
^lemblance of the amygdaloidal varieties to the back of a toad or
^t is a corruption of the German Todstein (Deadstone), so called
^)ecause the rock was considered to be unproductive of ore. It
is also known as dunstone, channel, blackstone, and cat dirt,
niie latter name is applied to the soft decomposed green variety,
l>ut the remaining terms appear to be used more or less indis-
criminately by the miners. " Toadstone, or Channel," was the
name used in Whitehurst's time (1778) for the ophitic dolerite at
Black Hillock. In the Wakebridge mine, near Crich, the dark
coloured rock, often amygdaloidal, was called Blackstone, and
the softer and more decomposed parts were called Toadstone.

196 H. H. ARNOLD BEMROSE ON

Pilkington apparently used Blackstone as a general word for the
igneous rocks of the county. He applies it to the lava-flow near
Snitterton, to a lava or a sill lower in the series, and also to the
agglomerate, or else to the bedded tuff near Grange Mill. We
have already referred to the circumstance that the old geologists
considered that there were three beds of toadstone continuous
throughout the limestone which divided it into four parts, and
that they also recognised "chance" beds of toadstone which
were only local.

Some years ago the officers of the Geological Survey showed
that this opinion would no longer explain the facts of the case.
The geological maps of the county were made on the one-inch
scale before the microscope became an adjunct to field-work, and
when comparatively little was known about the igneous rocks.
The toadstones were mapped on the assumption that they were
contemporaneous with the limestone, and in some cases it was
found necessary to introduce faults which are no longer required
when the intrusive nature of the rock is recognised.

It was not until 1894 that the belief in the contemporaneity of
the toadstone was shaken. In that year the author had the
pleasure of accompanying Sir A. Geikie over the district. As a
result of his visit, an interesting section on the Toadstones of
Derbyshire appeared in his book on " The Ancient Volcanoes of
Great Britain," to which the reader is referred. Sir A. Geikie
pointed out that the toadstones include volcanic vents or necks —
the remains of the pipes through which the materials found their
way to the surface— and intercalations of tuff and lava, and at least
one intrusive sheet or sill. Previously to 1894, the author had only
studied the petrography of the toadstones, but since then has
mapped the greater portion of the igneous rocks on the six-inch
scale, and microscopical examination of many more specimens
has been made hand in hand with field-work. Though much
remains to be done before we can arrive at the history of the
Derbyshire volcanoes, we shall endeavour to indicate briefly some
of the interesting results which, up to the present, have been
arrived at, reserving doubtful points for future investigation.

Some of the outcrops of toadstone marked on the one- inch
map as contemporaneous lava-flows lose their simplicity and
become more complicated when examined in detail. One of
them proves to be two necks of agglomerate with an associated
bed of tuff higher in the series, another consists of several
lava-flows and a sill, and a third comprises a lava-flow, bedded
tuff, agglomerate probably marking vents, and a sill. Several
outcrops are found to be more extensive than was supposed, and
exposures which are not marked on the geological maps continue
to be found at intervals. For a long time we have had proof
that volcanic action took place at intervals during the deposition
of the last 1,500 ft. of the Mountain Limestone, but the finding

THK LOVnt <UKB0SirZSOC!» BOOLS OF DOtBYSHIllS. 1 97

ofbflmdsofasbiniocifaied with some loolL of the lofver Yore^
dak rocks his earned die hstocj of the vofeankr actioD in the
comity a stage fuiilici.

The ^neoos rocks maj be dmded into two dasses^ whkfaare
genenHyeaqr to diaiiuguirfi in a hand ^pmmrn^Tii^ massive and
fagmentaL Sooie of die uua&iie nxks inchide lavas which are
interbedded with die limninnf and have a lesioifair and some-
times slaggj stmctnre. Otheis consist of a ooaiaeij crystalline
dolerite or a fine pained basalt, cutting across the beds of
limestone, and are either siQs» vents, or dykes. The fragmental
rocks are interbedded tn& cootemporaneoos with the limestone,
or are vents which cut across the Kmestone beds. In some cases
so small a quantity oi the rock is exposed that its relations to the
sarroanding limcrtnnr have not been determined. It is probable
that the ignecww rocks of the county eventuallv will be classified
into more than a dozen vents, one of basalt and the rest of
agi^omecatc, with a few small dykes, about half a dozen sills or
iotnisive masses, Bie or more deposits of bedded tuff, numerous
bva-flows and thirmer intercalations of tuff. We will describe first
several of the vents, tufl^ without lavas, lava-flows, and intrusive
silk in the Mountain IJmestone, and then conclude with the
igneous rocks of the Yoredale series.

Volcanic Vents.

Hoptan Vent. — At the village of Hopton, about two miles
^outh-west from Wirksworth, and dose to the boundary between
the Mountain limestone and the Yoredale shales, is the most
^kHitherly vent in the main inlier. Like many of the Derbyshire
^Vents, it is not separated by any difference in contour from the
"Surrounding limestones and forms no feature in the landscape,
^ut from the nature of the agglomerate of which it is composed,
<^nd the manner in which it cuts across the upper beds of the
l^fountain Limestone, there is no doubt of its origin. It is
^liptical in area. The major axis is about ^ mile in length, and
lies in a north-west and south-east direction. The minor axis
is about \ mile in length. A short distance to the east of the
.^igglomerate the limestones are seen dipping lo to 20 deg. south-
east, which is in the same direction as the longer axis of the
ellipse. Immediately north of the igneous mass, the dolomitized
limestones dip south-east also, but as the hill towards Via Gellia
is ascended the dip decreases, and near the High Peak Railway
the beds are horizontol The loadstone was mapped by the
Oeological Survey as interbedded with the limestone, and was
supposed to be some 1,800 ft. down in the series and below the
toadstone seen in the cutting of the High Peak Railway. Two
curved faults were introduced to separate the agglomerate from
the Yoredale rocks on the south. There seems, however, to be
August, 1899]. 15

19^ H. H. ARNOLD BEMROSE ON

no reason for the faults now the intrusive nature of the rock
is ascertained. About half a mile south-east of the vent, and on
the opposite side of the valley along which the Wirksworth road
runs, is the Kirk Ireton outlier of Shale Grit. In Stainsbro Quarry
the grit is seen to dip 15 deg. south-east, or in the same direction
and almost at the same angle as the Mountain Limestone near
Hopton. If some springs lower down the hill than the quarr>' be
taken as the base of the Shale Grit, there is about 700 ft. for the
Yoredale beds to come in between the Mountain Limestone and
the Shale Grit. Half a mile south-west of the vent the shales are seen
to be nearly horizontal. Very good sections of the agglomerate
occur along the Wirksworth and Carsington road, and' also on the side
of the road which has been cut in the bank of the ravine leading
down from Via Gellia on the north. The rock consists of a
coarse tumultuous agglomerate composed of numerous small
lapilli, with many more or less angular blocks of dolerite and
basalt. The agglomerate is pierced by at least three veins or
small dykes of a black fine-grained rock, enclosing reddish
fragments, which contain felspars and are probably small pieces of
the agglomerate caught up by the dyke. Plate IV, Fig. 2,
is from a photograph of the agglomerate on the Hopton and
Wirksworth road.

No bedded tuff has yet been found in connection with the
vent. Any such deposit, if present, would probably be in the
Yoredale shales, of which no good section is seen in the imme-
diate neighbourhood.

The Speedwell Verity about a quarter of a mile S.E. of the
entrance to the Speedwell mine, near Castleton, and between the
800 and 900 ft. contour lines, is a small vent, elliptical in outline.
It pierces the limestones near the base of the northern slope of
Cow Low, and is the most northerly vent in the county. The
limestones may be seen dipping about 20 deg. N., on the north,
south, and west of the agglomerate, and within a short distance
of it, so that the igneous rock undoubtedly cuts across the beds,
which, from their position, are very near the top of the Mountain
Limestone. The agglomerate is not well exposed, but a portion
of it forms a low ridge covered with grass and about 80 ft. in
length. It is composed of a mass of small lapilli containing
crystals and seldom vesicular. Scattered through this softer and
more decomposed rock are blocks of a doleritic type, with
minute felspars and an isotropic ground-mass.

Grange Mill Vents. — The most interesting group of vents is
found at Grange Mill, about five miles west of Matlock Bath.
Unlike the majority of the Derbyshire vents, they form two hills,
which present a marked contrast to the scenery of the surrounding
limestone. Two dome-shaped hills, with grassy slopes and well-
marked contours, rise from the valley to a height of 100 and
200 ft. respectively. Their summits are more than 900 ft. above

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. I99

the sea. The larger vent covers an area measuring 2,400 by
1,300 ft, and the smaller one an area of 1,300 by 900 ft.
Gocxl views of these hills are seen on the roads from the village
of A^ldwaric and from LongclifiTe Wharf to Grange Mill. The
smooth and steep grassy slopes consist almost entirely of a grey
rock with green lapilli and a few limestone pebbles. It weathers
into spheroids, some of which are well exposed opposite a cottage
in tlic southern vent close to Grange Mill, on the road to Winster.
On tlie hillsides are found a few blocks of saccharoidal limestone,
sonae of which are several feet in length.

The rocks in the immediate neighbourhood of the vents form

? Spring

Fig. 4.— Plan of Necks and Bedded T(;ff at Grange
Mill, Five Miles West of Matlock Bath.— ^Jxr A. Geiku.

Ir^northern part of a dome, the longer axis of which ranges

, "^.VV. The two vents lie on this anticline. In several places

of^ il*°^^°"^ *^ ^^^" within a few feet of the agglomerate. S.VV.

. ^He northern and smaller vent, it dips N. or N.W. at an angle

,. ^o to 15 deg. South of the southern vent, the beds are much

J^.^rbed, and at one point their upturned edges may be seen

J. **^ing at the agglomerate. There is, therefore, no doubt that

^ igneous rock traverses the limestone beds.

East of the vents is a small valley with its eastern slopes

., ^^ing up to a well-marked escarpment of limestone higher in

.^ series. This escarpment reaches a height of 1,000 ft. above

^ 5ea, and may be traced from near Whitelow Farm, where the

200

H. H. ARNOLD BEMROSfc ON

beds dip south-east and east, to Shothouse Spring, where they dip
nearly north.

West of the vents is a smaller and less marked escarpment of
limestone, which may be traced, with the exception of a few breaks,
from near Aldwark Grange road to Shothouse Spring, where it joins
the eastern escarpment A bed of laminated tuff underlies the
escarpments on both sides of the valley. It is about 90 ft. thick
and made up of alternations of finely and coarsely laminated bands
of lapilli in a calcite cement It is exposed at Shothouse Spring
and near Whitelow Farm on the east, being continuous between
these two places, as indicated by fragments in the grassy slope. It
can also be traced on the western side of the valley from Shothouse
Spring to within a short distance of the Aldwark Grange road.

The limestone resting on the ash is nodular and concretionary

(Figs, 4 tinds rtprinted^ by permission^ from
of Britain.")

The Ancient Volcanoes

Fig. 5— Skctton Across the Smaller Volcanic Neck and the
Stratified Tuff in Carboniferolts Limestone, Grange
Mill.— *Sir^. Geikie.

I. Limestone 2. Stratified tuff intercalated among the Limestones

3. Agglomerates

in character, and similar to that found above the tuff bed at
Litton, near Tideswell. Though no thin bands or intercalations
of tuff have been found in the escarpments, recent examination
has led to the discovery of numerous minute lapilli, distributed
irregularly through the limestone up to a height of at least 18 ft.
above the ash at Shothouse Spring. The clay bed in the adjacent
quarry, which contains nodular pieces of limestone with lapilli in
them, may possibly be the decomposed portion of an ash or ashy
limestone. The general arrangement of the rocks is shown in
Fig. 4, and a section through the smaller vent from east to west
in Fig. 5, which are from blocks lent by Sir A. Geikie. The
tuff has since been traced farther to the south-west, and beyond
the boundary of the plan (Fig. 4), and the southern vent a short
distance farther to the north-west. Two small dykes of dolerfte
traverse the southern vent, and are only seen for a short distance.
The northern one is at least several feet in width. The southern,
which is much smaller, penetrates the agglomerate to a height of
several feet near the roadside, and either dies out or changes its
direction and turns inwards into the hill.

THB LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 20t

Ember Lane Vent, — Immediately east of Bonsall, and about
two miles north-west of Cromford, a coarse agglomerate is
exposed in the banks of Ember Lane and in the field above. It
extends over i,ooo ft. in a north- west direction, and at its broadest
part measures nearly 400 ft. It is remarkable for the large
admixture of calcareous material with the volcanic detritus. The
rock may be described as a calcareo-igneous breccia, and consists
of an intimate mixture, in varying proportions, of limestone
fragments containing fossils — some angular and others more or
less rounded, and of volcanic lapilli, which are often of a dirty
green colour. A short distance higher up the lane it consists of a
more comminuted volcanic detritus containing a few limestone
pebbles as large as one's fist firmly embedded in it. The posi-
tion and extent of this agglomerate and its relations to the
surrounding rocks, as far as they have at present been ascertained^
are indicated on the accompanying map, Plate III. Unfor-
tunately there are no exposures showing the dip of the beds of
limestone contiguous to it. The only rocks seen near it consist
of quartz or silicified limestone, from which all trace of bedding
has been obliterated. The composition and appearance of the
agglomerate, and the fact that it cuts across the strike of the
unaltered limestones 500 ft. north of it, seem sufficient to justify
us in considering it to be a vent.

On the southeast it al)uts against a much decomposed vesi-
cular toadstone, which apparently belongs to the same lava-flow
as that which forms the summit of Masson Low, and on the
north-west there are traces of a similar rock. Two other and
smaller patches of agglomerate, one a short distance north-east
of Low Farm, the other north-east of Bonsall, probably mark
two smaller vents.

Kniveian Vents, — Several exposures of igneous rock are found
in the inlier of Mountain Limestone, near Kniveton. Near the
western boundary occur three or four patches of agglomerate
which probably mark the position of vents. The largest of these
traverses the upper beds of the Mountain Limestone and
perhaps also the lower beds of the Yoredale shales. It covers an
area of about 700 or 800 ft. by 400 ft., is cut by two streams
and forms the ridge of a hill between them. The beds surround-
ing it are very much contorted. On the north and south the
limestones dip east and west at high angles, forming an anticline
through which the agglomerate has made its way, and on the west
the beds are vertical with a N.N.W. strike. The agglomerate
consists of more or less rounded blocks of a vesicular dolerite
and pieces of limestone mingled with a finer deposit of lapilli.
Half a mile north, and near Lea Hall, is another small mass of
agglomerate, of which only a few feet are exposed. Its
boundaries have therefore not been defined, and sufficient evi-
dence has not been obtained to say whether it is a vent or a

202 H. H. ARNOLD BEMROSE ON

bedded tuff. Another small patch of agglomerate is found south,
east of the large mass, and probably marks the site of a vent-
since it apparently cuts across the strike of the limestones a short
distance from it. The fact that the country is covered by a drift
renders it difficult to trace exactly the boundaries of some of these
patches of igneous rock.

Tuffs Without Lavas.

Some of the toadstones interbedded with the limestone con-
sist of bands of tuff unaccompanied by lava-flows. There are at
least five of them. The thickest is at Ashover, in the small inlier
of Mountain Limestone. A shaft was sunk in it to a depth of
2IO ft, but the bottom was not reached. It is seen in two
cuttings which have been made to the limekilns on the east side
of the road between Milltown and Ashover and dips beneath
the limestone. For some feet below the junction it is much
decomposed. It is laminated, contains fragments of chert, of
limestone, often rounded, and of amygdaloidal dolerite, and is
traversed by veins of calcite. The matrix is composed of lapilH,
cemented with volcanic dust and calcite.

At the village of Litton, near Tideswell, is a well-banded tuff
intercalated with the limestone. It may be traced from near
Tideswell I^ne Head on the N.W. under the limestone escarp-
ment of Litton Edge, which dips about lo deg. N.E. to the Peep
o' Day, the highest house in Litton. It is exposed in the fields
north of the village, and at the place where it crosses the road.
The author has not yet been successful in following it from this
point down into Cressbrook Dale, though it is mapped by the
Geological Survey as continuous with a similar deposit on the
eastern side of the Dale. Its greatest thickness is about 1 50 to
200 ft., and it appears to thin out to the N.W. and in Cress-
brook Dale. It consists of alternations of fine and coarse laminae
of a green and yellow colour, with pebbles of coralline limestone
and blocks of dolerite or basalt up to 18 inches in length. The
matrix is formed of very vesicular lapilli cemented by calcite. In
Cressbrook Dale some portions are very fine grained, and slabs
are found about a foot in length which can readily be split into
thin laminae. Below this tuff, and separated from it by 15 to
20 ft. of limestone, is a lava-flow 10 to 20 ft. thick seen in
Cressbrook Dale. The limestones above the Litton tuff
contain a few lapilli up to a height of at least 18 or 20 ft.
The bedded tuff at Shothouse spring has already been
described.

A short distance N.W. of Tideswell a bedded tuff is exposed
for a distance of 50 ft. Its thickness is unknown, as the base is
not visible. It consists of laminae, but the component fragments
are not so small as those in the ^nely-banded tuffs. It is hard,

THE EX>WEX ClKBCSOlUifjirTf ^ZCjL.^ ZW ZWiJ^'SSJSKS^ ZffiJ

and consists of ^denJau: JsgSSt lac^'jiig. jl bzs irnn. ax ixsn: in
diameter dowuwudi^ ao^ csncsmf .^ihfsis ^ 'miien»t.

The fifth tnfrbed aeons sii !die T':c%2Qai(e siaua in Tissxnpm^
probaUy oiii|' a sbext ^Stojutut xuT^pt rne man: jsmm^ it IfL^vasaoL
LimestoncL A dtamgcGXL aC x -wll ie faimt jmoer tot ipneoiff
rocks of the Yoredile ames^

Near SfKurov P^ las: vmoer "ns: sicanr frame iihfccx ^ a
gnumlar limfanBiie oaacsinmf .uxniierDOi iPnircBour ogiiU: wtx
felspars in chcnL Tbcy iipert na: 2?r .7=21- tm: tare •maeinir twen
obtained in makrng a :riezi:& nr ncastTrrnurst. buC sc^ jircibBtihr
from the opper bt& (s£ ±ie Minmt&m Isnusskzmt or :i^ ijue 'X^
the Yored^cs^ Thtf are 7mtrnr..m^ ixscanse ':3keT pi« jcrdic^-
tion of a nungDm^ of v>:itha3iir tassxDs- wtx '±Jtt imKSsnoes is :i^
northern panof i^acca.

The fcna-flovs fiodk gHxatoe as <dx£e=es: xxac^azmL. mat wcpt t£
limited borrzancsll ^^"^^■' Tht vzucazxutx inam viuct tr^ tufif
and laras were cjenapd vcse BnoiE amc 'J zd£ ;iot rx-pe. £src ite

bva streaaBsaniddcpcsx3^aQEf''dif 2K1: esr^end i:: £ gpgg: 'Oiffamoc
from the venls.

Ersdeeace of dnc Tirirrirg ore :e' :±it: seru-h-jv^ xitirc tx' ±ieir
limiied on^e maj be occcxa&c ikx tinrr tnut itrcoros ;if TOinir^.
bet abo by aa exaaBaracicc: -af -riier uccir:«rrct jb tht- itud. Tbe
foikywing laiiaiaocDS ^<f '±it '±irdtxktxB z€ -cht I'jadsi-ciae, -rrucii
is an amrgdakxidal irriL. la ttte mitri:i!' cif Cnct Hill irere
nodcod bf Mr. AIwsp' -dsnuf rnmir^: ^r.iesnrrfCins. •*-% t^ed t.€
cIiT otae foot diadk tjecomes vriiizi £ sricir: 'Qifrjanoe i-QuniCics ieei
ttsrrk^ and oranfflaiirtf- Iszrce riufduies af campaci toadsicoe. 'viiiifi:
thf tbkk bed cf icatfteuoe acruslhr simk tttrciu^ £: cme fib&ft
Cminosbes ao a rircn tied ac -irt cidier mine. Tbe beOE n'ta^
tnoed ontfTffraaLMgilT frcGc mmt !;> mnke.*' In twQ mmes oc tbe
vesi sade 'cf rae k£ siK iQadsi-unt v^as nacbed zi hz &du ;:5
£vhoaa^ amd ats sibJcikiDeBf vss icmac it bt 21 iaibaiDE aord r?
Qiboms ropecSTKdij.

In dac socatamiisof l5ae MLidiaDd Eal'iri-rtbe GtrojciptaL Sarpej
Q^oos facad liatt nt«& bads of iimesiciat is canard ac CresstiPciQik
asd LisssiD Tmnnes were sqaurzatxC &t Lin-os M.ui& bj a mass -of
toadssosae »3aJda ^aaiJT- sttaiiked a thircknest cif 30c fu Tbere
^:js aio ^p> of aihwaericjo in the unDer}vin^ imiesiiwintif a: "^lerj
jK^ncDoo wicb ifee loante-ocKi Tbe diiecn^err af ttr&rceciuf licaesi-ODe
^ad bedded tofal tbe 'toL&e of thi^ loadsicirit Bii;ii;»cirts 'die tipinioa
that the nxfk scpresecci a krB-5c*ir and ivtx nn intrusri^ siH
Tbeie b aibo ciJteiwje tba.: -"Jhf Ued tkitif ox 10 "^it CTppiosn-f
<iiiecdoa ac Gocafi Low an tbe Aiiioc»ume toe Bunoo r^mjiie
load. The Tsja^er bod -c£ ici&dsicyDe id the Matlock difina
appeass 20 thro cue a riran diBaiDct cas: ^if J u^y^tt VCotod. Ii if

204 H. H. ARNOLD BEMROSE ON

probable that the largest of the lava-flows did not extend to a
greater distance than five miles. That which forms the second
toadstone of the Matlock District can be traced for a distance of
four if not five miles, and the largest in the Miller's Dale District
once covered an area of at least 4^ by 2 miles in extent

The beds generally vary in thickness from 100 ft downwards.
But the two largest lava streams probably attain a greater thick-
ness than 100 ft. Near the top of Cressbrook Dale a small flow
10 to 20 ft. thick is seen. Immediately south of the fault which
bounds the southern portion of the Tideswell Dale inlier are two
small lava- flows 15 to 20 ft thick, and separated by about 15 ft
of limestone. There are indications that some of the beds are
made up of a succession of lava-flows. The toadstone at Litton
Mills was considered by the Geological Survey to be composed
of at least five thin beds, which may represent different out-
pourings of lava.

The contemporaneous lavas consist of a dolerite, black or dark
green when fresh, but grey, brown, chocolate, or light green when
weathered. The upper and lower portions of a bed are
vesicular and the central parts are often harder and free from
vesicles. The vesicles are irregular in shape and size and are
frequently filled with calcite and other alteration-products, the
exact nature of which has not been determined. In a few cases
the amygdules consist of jasper or of chalcedony. The rock is
often traversed by veins of calcite and in some cases contains
small nodules and veins of quartz and of jasper. The so-called
" Buxton Diamonds," small quartz crystals, are found in geodes
or cavities in the toadstone. The limestone underlying the
toadstone often presents a very uneven surface. Numerous
holes, several feet in diameter and in depth, occur in it, in such a
manner that in a section seen in a vertical cliff the upper
boundary of the limestone is a series of irregular crests and
hollows. A similar contour is seen in the surface of the lime-
stone below the bed of shale and the wayboards of clay at Crich
and other localities. These hollows are probably due *'to
carbonated water circulating along the junction of the beds long
after the formation of both limestone and toadstone." When
very much decomposed the toadstone weathers into a greenish
or yellowish clay and sometimes retains traces of its origin in the
green amygdaloids which can be picked out of the softer portions
of the mass.

We will now give a brief description of a few of the lavas. At the
bottom of the valley of Miller*s Dale a small dome in the lime-
stone brings to view the upper part of a lava-flow which is about
150 ft lower in the series than that seen in the railway cutting
above. It appears soon after leaving the last house in Miller's
Dale and can be traced under the limestone escarpment as far as
Ravenstor, where it disappears under the limestone with a S.E.

Proc. Geol. Assoc, Vol. XVI.

Plate V.

Fk;. I.— Intrusive Dolrritr above Limestone, Tidkswell Dale.

d = doUrite. I = limestone ( marmoriseii, )

Fig. 2. — Lava and Tufaceous Limestone resting on Limestone.

Buxton Lime Firms Co.'s Quarry, north of Miller's Dale Station.

t=iava, a = tufcueou5 limestone. l—limt%ionc^

(J^raw PAi?/o^ra/>As f>y //. Arnold- Bemrou.\

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 205

^ip. It is very much decomposed, vesicular, and amygdaloidal,

and is fairly typical of the lavas of the district. The junction of

:mts upper surface with the limestone is visible. Under Ravenstor

^he junction has been removed by water flowing along the top of

Yhe impervious rock. This has resulted in a small cave, the floor

of which is toadstone and the roof limestone. The latter rock

contains cubes of pyrites and the upper surface of the toadstone

is soft and contains numerous small crystals of selenite, probably

due to the decomposition of the pyrites. The upper decomposed

portions of lavas in other parts of the district often contain

pyrites, and this mineral is especially characteristic of the

agglomerate at Kniveton and the bedded tufls at Tissington.

A lava-flow may be preceded or followed by a fall of volcanic
tuff. An interesting example of the former occurs near Miller's
Dale, and of the latter a short distance from Matlock Bath. The
lava, which may be traced from Litton Mills to Great Low, is
exposed along the railway cutting, and is probably the same bed
as that which occurs on the west slope of Hammerton Hill, forms
a ring round Crichley Hill, with a cap of limestone on the
summit, and also composes the hill called Knott or Knock
Low, a prominent ridge N.W. of Miller's Dale Station.

East of the station, in a tram line cutting belonging to the
Buxton Lime Firms Co., Ltd., the junction of the lim'^stone and
the toadstone above it is well exposed. Two feet of clay rests on
the limestone, above this are 2 ft. of a platy and fine-grained,
crystalline, tufaceous limestone with few organisms. This is fol-
lowed by an amygdaloidal dolerite about 9 ft. thick, which probably
represents a small lava-flow. It is succeeded by a well-bedded
and coarse-grained tuff at least several feet in thickness, and this
'n turn by the lava-flow, which extends for a distance of several
Oiiles. The coarse-grained tuff is seen several hundred yards to the
^est, near the footpath to Priestcliffe, and the tufaceous limestone
^pj>ears resting on the top of the limestone in a quarry several
hundred yards to the east. Traces of a coarser and harder tuff are
^Iso found further east. The junction of this bed of lava and
the limestone is at present well exposed in the quarry at the foot of
tCnott Low on the opjK)site side of the Dale and immediately
riorth of the station. On the limestone rests several feet of a
cJecomposed calcareous tuff or tufaceous limestone similar to that
near the tram line. It is succeeded by the vesicular dolerite
'Which forms a greater part of the Low. The white limestone, light
brown tufaceous limestone, and dark-coloured toadstone, are
easily distinguished at a distance Plate V, V'lg. 2. This hill is a
short ridge rising steeply from the jurrounding country Its
isolated position and contour suggest a volcanic vent ; but closer
examination proves it to be one of the few cases, if not the only
case in the district, in which part of a lava-flow forms a prominent
hill. On the north, west, and south-west, and in the quarry on

206 H. H. ARNOLD BEMROSE ON

the south, the limestones are seen to dip regularly beneath the
toadstone, which in some parts of the hill weathers into
spheroids.

The lava which forms the summit of Masson Hill, and which
may be traced for several miles, was succeeded by a fall of
volcanic tuff. The bedded tuff is best seen near Tearsall Farm,
and may be traced for at least a mile along the upper surface
of the lava in a westerly direction. Near the farm the finely
laminated tuff of a buff colour and similar to that at Litton is
seen dipping under the limestone and resting on the vesicular
toadstone. It is about 20 ft. thick.

The Sills.

Several of the toadstones occurring in the Mountain Lime-
stone are undoubtedly intrusive sheets or sills. They differ from
the lava in several respects. They weather less rapidly and
consist of a hard coarsely crystalline dolerite or a basalt, and are
non-vesicular. In some cases they have altered the rocks in
contact with them, and cut across the beds of limestone. But
in no case has the author found any alteration in the limestones
due to a true lava flow. Unfortunately all these characteristics
are not always present, or they are not to be found owing to the
very small exposure of rock seen or to the removal of a very great
portion of it by denudation. Sometimes the toadstone trans-
gresses the beds of limestone, and the latter are not altered, at
others the limestone, above or below the igneous rock, has been
marmorised, but the dolerite is not seen to cut across the beds
owing to so small a portion of it being exposed. The structure
of the rock appears to the author to be a less decisive test of
intrusiveness than its behaviour with regard to the surrounding
limestones. Each case should be decided on its merits, and it
would be unsafe to decide on the intrusive nature of a rock by its
structure alone, unsupported by field evidence.

Peak Forest SilL — In Dam Dale, south of the village of Peak
Forest, is an intrusive sill of ophitic dolerite. Its base is not
seen, and its thickness is unknown. The portion exposed in this
small valley does not cut across the beds, but its upper surface
dips regularly beneath the limestones in a N.E. direction. The
limestones immediately above it are marmorised for a distance of
about 5 ft. A few feet higher up they contain chert nodules,
and are partly dolomitised. The metamorphism may be traced
about 800 ft. horizontally on the N.E. of the outcrop, and for
about half that distance in the limestones on the N.W. on the
opposite side of the valley, south of Damside Farm. The mar-
morised limestone is saccharoidal, and composed of crystalline

THE uywEM OkiLHcaaFQcDUf ai^icij^ IH :aa3T5?aaia^ ar^

cikite, siKmiQg liit tSaxBCiecBcrr .^itf^^^^^l^!l uniK' ^e mcn^
scopt. TvD jacrds Above liifr iimmui. He innsssuiii*: i::nmin&
tiaccs of OB^nnsms «T>tf pgtr4t#<t ^ scnsr crxsculims: "'^w'"^ ur

crjrstaLDine^ opixxtic ciiiviDe^dcilsmz:. iiir lear He umrnuit r jlisb
its ophitic strDcmrt and tecama inin?; imt fninisi* 1: s "ftss:
■xom vcsicics or sin^SfcouQDGB.

/W Z«£i: -Sul — ttot mikr iimir&'Sas' a: tie ?'fak J :i«s: flil
^ coause opteac ddiern^ » ussl :gwgnif usair^ ui. urms if :ne
^^uisKie. It cocaiattt. of soEOen. jmc ^inttrem. i^iu^iuiii. rrrvjiar
u shi{»e amd comiKsed bv x sarnivr ^auL JLtm-jitfa :ne vtuue
<:>f the rocks mssodaBSnA irtx x iiBste -nu: ym :i£s:i mr%*si vit il
^leiail, ^liffM'.lraia end^niGe ix» :esL mnmusst iv -yimiiST l jrrjiaizbt
Mibax it s a sdH. Atioac fonr imsCBsst issc i: rxe y 1. ire i dem
lai^ge blods d veD 2zxannsr!iMs£ lxwesrjx&. ^"tf ifliicijer .uic ^sris
^unber in tiie aazac dirvcbsir s x sxxoiL Jimsaoine isdr:nienc n
^^^hkh tJ^c^irffd^XX-glHiingU*: :f r ifcc 7'ie ud mait y: ±e
IKlack HiDock BBDe h an iie £ I. Tiar^n :f rie ti:r:ner^ ^ar:.

^^nrplj sonda jcros :3a: s^ad ir.d zaaaes i itnu^ iistance :i: :ne
"Ernest of aja old Hsxsoziat ■ :j iw" ji.. :n. -v^uai ne :ia& iin i iea. v.nr.:ir?ij
^^J^e S.W^ aad occcmKs ioict tccL c r-sithe! rie imailer :cr::cii
^of ibc odcrofL Tre !:3iiss&:ni» ir<* ««i«n: i ihcr: iisnini'-it -r-yn :he
•^^S^E. baandarr i:. <fc rean^ «:iiirL ^»: "nar rie unerjis xiai5s rata
-=^^cros the bB& cf irzujfiiice ^. itrie aimer a: -j:e nyir: c iic»
^C3ad«r Tfarni ba: tier ire ti:c nami-jraed.

On tbc X-W tte nnrfgrtuita i:^ S. Z. ir i ^rtuill vripe. Tiit

» MppaasxL-} r.ia scr-jm lie .ime^c^re :tiiis Ji 3w>

OQ 13 S £. "toimiarT. I- ±e :<il imdcir. nrjirii :»irv«ea

asjiDaraed rmeir.'aat lad "Tie ^srjirimerx m ne N' Z.. ip*r?

Eccad buodk^ '^ a^jp^meiace L- jeren. ^biies "jot -ie X-v^'.

i&c "ioucrx* 3 it»r7 -r-in. itjI :ne .;iiiest.->ne :iiii:w^ c

b«a ■giageued tc i snaH -sridrm 1: s lesr r«r.nir :r. ±e

. aad tfse arr.^ -4 zrx TLnmcr-jaaL A rit-^ ieiiis :.: ±e

_^^S^-W. snsalL cioc^ cc iumiar rvtk ir* iesn -nscrq zr. the 'iineit.-.ce.

~ Jlioc prj^afciT ffcjresetc inia.1 :iiiiierj -y ±it :nr-r.er c«:rt:«^n of

"^^hc bed lieft u7 ^/err^iJaT-rji, Other ry-xJer.itja :f .iraricr :- ±e

"i^'iii I I III \i h I r>ed IT* dced 'y Wurehiinc irhc rv-is i ;iaa or

"^dic irprntn ni rhe ztncrrxahcciL ihcwrji nat ir Eia»:Jc H ILcck,

^^atee ±e rock 3 ir ±e iuriaie. i shar: wis ^unk zzc. fi:hooas

^^iichoat the facOMi be^lnc reached ±i:u^h r ir-r/ :hir.A.^ '±tt rrxrk

"^WB sank d^rjt^/^ ard rhar ir :i±er ;»ai:ii3, W'.nj^ 2 ihor: -istirxe

"^o die X.E^ tfee igneccs rr>:k :ir -'±ar:nei' vared froen :-S :»>

^ fohona in rhriHnrw TSt rsck is zenenlly 2 'rcarse-zTiined

^foicrite^ bat owardi the aiirthem bc'-ndar/ :z :s r.ner -jt. zrain

^nd loses its ophfcc srmcr^re.

A ¥csiailar doietice axa^ be traced >. 1 rj:fth-^est direchoQ :o

2a% M, m, MM3BOIU>

Qdov RjIdc; boc its RfatioaB io the d fsnci
ifiHiwiind. lo the Bbck HBIock Moeteip
bnth tjpes of the doicriie and a smbJI piece of
sU3oe^ The Geological Sonr^ o&zzs were of •
shaft was on one of the vcncs '^'"^^ m^u^ \\ die t
Tbejr abo mcncion that Bmij fiagBenis of
in the tnaitonnr ThcK, and the pieces of _
oofftfa, lend wc^^ht to the viev that the shaft was sank m a ^ent,
bftt the distiibittksn and the ^anring thickness of the iiigiiec^
rather Litoiii the idea that tL was sank in the pipe ilinwij^h which
the sin fbond its way bdbre it spread between the beds of lime-
stone: The limestones on which this sin rests at its wcsieiu
boandarj aie aboot 800 ft higher in die series than those
immcdiatriy above the PtedL Forest sOL This estimatr is aimed
at by taking into accoont the dip of the beds and the Ul of the
groimd between the two places.

TuUswell Dale SUL — Another interesting sin occms in Tides-
weO Dale, half a mile sooth of Tidcswdl TiU^e. The only
▼isible portion is contained in a faolted inlier of Moontain Lime-
stone. North of the inlier is a smaU lava-flow, and sooth of it are
the two smaU lava-flows above referred to.

Intercalated with the limestones is a bed or stiatom of red
day Tcry much like a volcanic mud, which varies in thickness,
and vi sometimes absent in this part of the Dale. This appears
to have been foUowed by a flow or several flows of lava. At a
later period the intrusive rock made its way into the lava and
spread along planes of weakness. It is found to occupy different
horizons in the lava, sometimes resting on the limestone, at others
on the clay, and at others on the vesicular lava. This coincideiice
of the sill with the lava '\s a remarkable one. The metamorphism
extends some feet below the base of the sill.

Below the sill the clay has been indurated and rendered
columnar to a depth of 9 ft., and the limestone has been altered to
a hard saccharoidal marble to a greater distance from the junction
than the alteration lias extended in the limestones above the
Peak Forest silL That this metamorphism is due to the compact
dolerite or sill, and not to the vesicular lava below it, is shown by
the fact that the bases of the compact dolente and the mar-
morised limestone are approximately parallel. Where the non-
vesicular and compact dolerite rests on the clay or on the
limestone the clay is rendered columnar, and the limestone is
marmorised sometimes to a depth of 10 or 12 ft. Where some
feet of the vesicular or slaggy toadstone separates the dolerite
from the clay or the limestone beneath it the latter is unaltered.
The sill is not found to transgress the upper portions of the
vesicular lava, consequently it has not been sufficiently near to
the limestones above the lava to alter them.

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 209

H
S

fc:

flu
O

I >-< &j> Sm

•soiW

Tbc kI 2$ accctr 7^ n ±adc- jod ssbj be zsxxd km acc^r
K»'r 2 "g-"^ fr:ci 2CCI* ID wxrrt Iz s ««{Z i^ ^^^.^if ^I ic :ke ad

ac :=e zxrc* iz^t r^e^grcaec near ±$ =?pc=^ ^^ io^er scztees.
Tbc reck z= ±e via^J > 3 rzvcrsed bj =3=2Baoas i«bs dL
cExfVJZJt cr forties jCyCr c it. Tbe ^w-i Bg^^^-^M^f^ "m^eaaaat
n 2. birc ooczZi^e csBbue. 2DC 21 cne rzae vzi 3x2^y qoBTivd
Tie GdL yk2z^ PL ^X ind fiecxxB Fszs. 5 aad 7, aad tbc
tr^jcrxrrxi frooi pbocceo^ PL V, Fat i. will i^'^pfa^ die
poficr^ic o( ±e slI a=c :3 rrafinn :o ^le roc±s of dse

EU Si:L — A zne dizvn thrcc^ tbc osacics <3f tiv Gnx^
Yt3!3 T2=:zcs Dortb-«V5t. ssd -1 puiTiuLcti foc a ^^i^^iny of Half
a f"'"^ in a socdKcataS dirccrsco. passes thro^Ji the ceime of a
BBSS of o^jhibc doien&e. ckse to ck tlj^ of Ifaie. The
igococs rock a^caiezuly disipceaxs coder tbc Izmestoides on the
Dortb-tasc, whkh dip at an anoc cf re de& in tint dkeukm, bet
ft has noc been ascotaizxd vhcther it hxs mide ks «aj buaixu
the Hiaesu»e beds. On tbc sodh it cuts across die stiike of
the Hmestooes vhkb dip vest at an an^ of ic deg. The foot-
padi to Ib&e passes ihroogh a smaS rarine. ciit by a stream in the
^ueoos rock and die liniesrones to tbe socm. The path, after
passing tbroi^ a small vood, crosses tbe junctkn of tiK ioc±s»
and tbc limcstoues, within a few yards^ are Tery dystalbne. In
front, to tbe noftb, tbc toadstone rises in a steep siope^ and »Wr^
forms a prominent ridge, trending northeast. The slope and
ri<%e, which are now separated by tbe lariae, rise to a h^gltt of
more then 2co ft. from tbe depresskm which marks part of tbe
southem boundary of tbe igneous rock. There is no donbt that
this igneous mass oocapies difierent horizons in tne limestones
by which it is surrounded.

It may be either an intrusive boss or tbe lower part of the
pipe which supplied a sill bigber up in tbe series. If the latter
be the correct expbmation, the whole or a greater portion of the
sill and the limestones, amongst which it occurred, have been
removed by denudation.

Masses of ophitic doleriie occur in other parts of the district,
but sufficient woik has not yet been done to warrant anythii^
definite being saicl about them. We will content ourselves by
simply mentioning one in the neighbourhood of Bonsall which
covers a large surface of ground, and cuts across the beds of
limestone lying to the west of it, and is probably a sill.

Igneous Rocks or the Yoredale Series.

The latest traces of volcanic activity in tbe district are
found in the Yoredale shales and limestones. At Pethills, about
half a mile south of the village of Kniveton, are two bsinds of

l*^0€Z. G»

fAB^^mg

2o8 H. H. ARNOLD BEMROSE ON

Oxlow Rake, but its relations to the sill have not been precisely
determined. In the Black Hillock mine-heap the author found
both types of the dolerite and a small piece of marmorised lime-
stone. The Geological Survey officers were of opinion that the
shaft was on one of the vents through which the toadstone came.
They also mention that many fragments of limestone were found
in the toadstone. These, and the pieces of agglomerate further
north, lend weight to the view that the shaft was sunk in a vent,
but the distribution and the varying thickness of the igneous rock
rather favour the idea that it was sunk in the pipe through which
the sill found its way before it spread between the beds of lime-
stone. The limestones on which this sill rests at its western
boundary are about 800 ft. higher in the series than those
immediately above the Peak Forest sill. This estimate is arrived
at by taking into account the dip of the beds and the fall of the
ground between the two places.

Tideswell Dale SilL — Another interesting sill occurs in Tides-
well Dale, half a mile south of Tideswell village. The only
visible portion is contained in a faulted inlier of Mountain Lime-
stone. North of the inlier is a small lava-flow, and south of it are
the two small lava-flows above referred to.

Intercalated with the limestones is a bed or stratum of red
clay very much like a volcanic mud, which varies in thickness,
and is sometimes absent in this part of the Dale. This appears
to have been followed by a flow or several flows of lava. At a
later period the intrusive rock made its way into the lava and
spread along planes of weakness. It is found to occupy different
horizons in the lava, sometimes resting on the limestone, at others
on the clay, and at others on the vesicular lava. This coincidence
of the sill with the lava is a remarkable one. The metamorphism
extends some feet below the base of the sill.

Below the sill the clay has been indurated and rendered
columnar to a depth of 9 ft., and the limestone has been altered to
a hard saccharoidal marble to a greater distance from the junction
than the alteration has extended in the limestones above the
Peak Forest sill. That this metamorphism is due to the compact
dolerite or sill, and not to the vesicular lava below it, is shown by
the fact that the bases of the compact dolerite and the mar-
morised limestone are approximately parallel. Where the non-
vesicular and compact dolerite rests on the clay or on the
limestone the clay is rendered columnar, and the limestone is
marmorised sometimes to a depth of 10 or 12 ft. Where some
feet of the vesicular or slaggy toadstone separates the dolerite
from the clay or the limestone beneath it the latter is unaltered.
The sill is not found to transgress the upper portions of the
vesicular lava, consequently it has not been sufficiently near to
the limestones above the lava to alter them.

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE.

209

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2IO H. H. ARNOLD BEMROSE ON

The sil) is about 70 ft. thick, and may be traced for nearly
half a mile from north to south. It is well exposed in the old
Marble quarry. It varies in structure, being coarsely cr)stalline
in the centre and fine-grained near its upper and lower surfaces.
The rock in the quarry is traversed by numerous veins of
chrysotile or fibrous serpentine. The metamorphosed limestone
is a hard coralline marble, and at one time was largely quarried.

The Geol. Map, PI. VI, and sections Figs. 6 and 7, and the
reproduction from photograph, PL V, Fig. i, will explain the
position of the sill and its relation to the rocks of the
neighbourhood.

IbU SilL — A line drawn through the centres of the Grange
vents ranges north-west, and if produced for a distance of half
a mile in a southeast direction, passes through the centre of a
mass of ophitic dolerite, close to the village of Ible. The
igneous rock apparently disappears under the limestones on the
north-east, which dip at an angle of 20 deg. in that direction, but
it has not been ascertained whether it has made its way between
the limestone beds. On the south it cuts across the strike of
the limestones which dip west at an angle of 10 deg. The foot-
path to Ible passes through a small ravine, cut by a stream in the
igneous rock and the limestones to the south. The path, after
passing through a small wood, crosses the junction of the rocks,
and the limestones, within a few yards, are very crystalline. In
front, to the north, the loadstone rises in a steep slope, and also
forms a prominent ridge, trending north-east. The slope and
ridge, which are now separated by the ravine, rise to a height of
more then 200 ft. from the depression which marks part of the
southern boundary of the igneous rock. There is no doubt that
this igneous mass occupies different horizons in tne limestones
by which it is surrounded.

It may be either an intrusive boss or the lower part of the
pipe which supplied a sill higher up in the series. If the latter
be the correct explanation, the whole or a greater portion of the
sill and the limestones, amongst which it occurred, have been
removed by denudation.

Masses of ophitic dolerite occur in other parts of the district,
but sufficient work has not yet been done to warrant anything
definite being saO about them. We will content ourselves by
simply mentioning one in the neighbourhood of Bonsall which
covers a large surface of ground, and cuts across the beds of
limestone lying to the west of it, and is probably a sill.

Igneous Rocks of the Yoredale Series.

The latest traces of volcanic activity in the district are
found in the Yoredale shales and limestones. At Pethills, about
half a mile south of the village of Kniveton, are two bands of

l*ROC\ GH

I 1

To ^9^ /Wf/I

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 211

^unygdaloidal dolerite, which were considered to be either intrusive
or brought up by two parallel faults. The junction of the igneous
m-ocks with the limestone can be seen, and no evidence of faults
or transgression of the beds of limestone and shale has been
Xound by the author. In contact with the western band at its
upper and lower surfaces the limestone is black and finely
crystalline, and characteristic of many of the thin limestones. A
few feet above the junction the limestones are dolomitised. The
t>eds dip at a high angle, and the hmestones and shales between
the two igneous bands are nearly vertical, with a N.N.W. strike.
It is possible that the beds form an anticline, and that the two
l>ands of toadstone seen on either side of the axis belong to one
and the same sheet. Whether these igneous rocks represent
c:ontemporaneous lava-flows or sills which have been intruded
between the beds is uncertain, but we have now ample evidence of
igneous action contemporaneous with the deposition of the
^oredale shales and limestones.

Near the village of Tissington a deposit of tuff covers a large
extent of ground which is mapped as Yoredale Shales on the one-
inch Geological Map. It is generally a bedded tuff, but on
Wibben Hill is more like an agglomerate, the blocks of lava
embedded in it being larger, more numerous, and closer together.
The new L. and N.W. Railway passes through it. The folding
of the strata has caused a repetition of the beds to be seen in the
outtings and has brought this tuff into view four times. At its
second appearance near the middle of Tissington cutting the tuff-
bed is exposed to view from top to bottom, and is about 140 ft.
tihick. It rests on cherty limestones, which probably belong to
t:he upper beds of the Mountain Limestone. The tuff is
generally course in texture, often has a distinct lamination, and
<:2ontains numerous blocks of a dark blue or grey amygdaloidal
*~ock, distributed irregularly throughout its mass. The finer
;^oortions of the tuff are made up of lapilli, varying from one inch
^^ n diameter down to a fine dust. They are very vesicular,
^^irontain no crystals, and are an altered glass or palagonite. The
^ ower part of the bed consists of small ** ball-like " lapilli, about
^^iDne inch in diameter.

_ The ejected blocks found in the ash vary in size from several

^^^ nches up to a foot in diameter, and are more or less rounded,

"^^^esicular and amygdaloidal. They are not so glassy as the lapilli,

^^^nd unlike them contain felspar and olivine pseudo-morphs. In

"^^he thick tuff-bed there is an entire absence of non -volcanic

^^rnaterial. After the prolonged eruption, or series of eruptions,

^^^hich produced the thick band of tuff, there was a series of

^intermittent eruptions during the accumulation of at least 80 ft. of

^^he shales and thin limestones. Volcanic detritus was mingled

"Vith -.he ordinary sediment of the sea bottom. Some of the

limestone beds are free from tuff, whilst others contain varying

212 H. H. ARNOLD BEMROSE ON

proportions of volcanic ejectamenta, and thus a limestone entirely
free from volcanic sediment in one place passes into a tufaceous
limestone or a shelly tuff in another on the same horizon. These
intercalations of tuff, some of which in the shales are only j:-in.
thick, are seen in the railway cuttings above each of the four
exposures of thick tuff, and also in Crakelow Quarry.

It is interesting to notice the variations in the shales and thin
limestones above the luff. Near the centre of Tissington Cutting,
not far from Wibben Hill, there is a preponderance of shale. In
Highway Close Barn cutting the limestones become more
numerous and are closer together, whilst in Crakelow cutting
there is little shale. Some of ihe limestones thin out very rapidly.
In one place shale was deposited on the thick ash, and in
another limestone and the volcanic fragments from the feebler
eruptions which succeeded the great outburst fell in some places
where shale and in others where limestone was being formed.
This probably points to the shelving shore of a slightly sub-
merged volcano which produced the showers of tuff. The
position of the vent is a matter of speculation, and in the absence
of further evidence it would be unwise to give any decided
opinion. We may, however, mention a few indications of the
probable direction in which the vent may be looked for, and they
must be taken for what they are worth. We have already
described several vents near Kniveton which are distant about
half a mile from the nearest part of the ash, and about
two miles from the farthest place to which it has been traced.
The structure and composition of the lumps of lava found in
these vents are exactly like those of the blocks found in the tuff,
and it is quite possible that one of these vents may have supplied
the tuff. In such a case we should expect to find the thick band
of tuff in other localities and directions amongst the Yoredale
rocks. But up to the present no traces of it have been found
west, south, or east of the vents. It appears more likely, how-
ever, that the vent we are in search ot is nearer the cuttings.
Wibben Hill, close to the village of Tissington, has the contour of
a vent. The deposit of tuff covers and surrounds it on all sides.
North and south of the hill are small quarries in limestone, which
is overlain by tuff. The shape of the hill and its position with
regard to the surrounding; tufaceous deposit, and the larger and more
numerous ejected blocks on its slope, are in favour of its being a
neck or the lower portion of a volcanic cone directly connected
with the thick deposit of tuff. The only alternative supposition
appears to be that it is a small sharp and very symmetrical
pericline of limestone covered by a layer of tuff. It is probable,
however, that in such a case the softer covering of tuff would
have been removed by denudation, and have left the limestone
exposed. The question for the present must remain unsettled.

Plate VII.

^-^^^

Cofiimtt^,

CfiMtiittt*d.

N.W

1 Scale

ftp 7.0 Sft »0 rHy ardft

-^—-^ L^=J

THE LOWER CARBONIFEROUS ROCKS OF DERnVSIIIRE. 213

PETROGRAPHY.

The Massive Igneous Rocks.

J ""IThe microscopic structure of a few of the dolerites of

J ^*~t)yshire was described by Mr. S. Allport and Mr. Teall.

S? ^^94 the author described more fully the petrography

P^ ^he dolerites and also that of the tuffs. The massive

'p'^^^^ous rocks have three main types of structure, viz., olivine-

'>^.^4

rite with granular augite, ophitic olivine-dolerite and olivine-
Jt.

_*"The dolerite with granular augite consists of augite in small
^5"^ ^ *^s, olivine in idioraorphic crystals, plagioclase, giving lath-
*"^Jf:>ed or tabular sections and magnetite or ilmenite in rods or
^*'^^-i«ns. A small quantity of interstitial material is sometimes
P^'^^^^nt. This type is generally found in the lava flows, but is
'^^^^ x-estricted to them. In the lavas the felspar crystals often
^^^^i n a considerable size, but in some cases occur in bundles and
P*^^«"»rjes of micfolites and in skeleton crystals. The rock
^'^rar^^diately surrounding a vesicle will sometimes be composed
^^ "^^ery small felspars in a base of iron-oxide. Though the
"^**~^^rals in a lava are often fresh, in the more decomposed
P^'^^ions of the rock they are entirely altered to serpentine,
^*^*^^>»ite, calcite, oxide of iron, and other decomposition products.
Y^ ^'W.ombic pyroxene which often occurs in groups of crystals is
^^'-^ «^<1 in some of the lavas.

T^'he ophitic dolerite consists of augite in large ophitic plates

^'^r^^^ing the ground mass in which are imbedded the idiomorphic

^ ^^'^ine, the plagioclase often giving large lath-shaped sections

^??J^ magnetite or ilmenite. This type is found in the intrusive

^-*^» and is also associated with the other two types, in outcrops

^^^^e relations to the surrounding limestones have not been

^^^ ascertained. The whole of the minerals are frequently in

z.*^ ^^Imost perfect state of preservation, the olivine, which is the

P^^ to undergo a change, often only containing small traces

^^rpentine along the cracks. The olivine is frequently

^ J^^^.ced by a mica-like mineral, the exact chemical composition

r '^ hich has not been determined. A qualitative analysis made

g» *" the author by Mr. Archbutt from a Pot Luck specimen

j^'^ed that the oxides present besides silica were iron-oxide

g ^Comparatively large quantity, a fair amount of alumina, a

P^^^ll quantity of magnesia, and small quantities of soda and

^^^^sh. This analysis differentiates it from iddingsite, which,

^^^^rding to Lawson, is non-aluminous and contains lime. Its

j^^ical properties agree with those of an almost uniaxial

'j».**^^ral. This pseudomorph occurs largely at Pot Luck, near

^^^swell, at Peak Forest and other localities. A similar

^^^xidomorph is also found at Peak Forest, having the same

August, 1899.] 16

214 H. H. ARNOLD BEMROSE ON

optical properties and differing in colour and the small develop-
ment of cleavage. The olivines in the Peak Forest sill are partly
fresh and partly altered to this mineral, which is probably a first
stage in the alteration to the Pot Luck pseudomorph. The ophitic
plates of augite vary in size from 7*5 mm. in length, and from 5 mm.
by 2*5 mm. downwards. They often show well-developed cleavage-
cracks and polarize in brilliant colours ; many of them are twinned.

The basalt contains olivine and large augite phenocrysts.
The phenocrysts of olivine and augite lie in a ground mass of
small felspar laths, of augite in small phenocrysts, grains and
prisms, which give lath-shaped sections, and of magnetite or
ilmenite. There is little interstitial matter present. The rock is
a typical olivine-basalt, and in a very good state of preservation,
all the minerals being quite fresh, except that the olivine is some-
times altered along the cracks. The olivine crystals have a well-
marked outline, and often give the usual six-sided sections ; they
vary in size from 5 mm. down to '06 mm. This mineral often occurs
in groups of several individuals and may frequently be detected
in a hand specimen by its green bottle-glass colour and fracture.
The augite phenocrysts are of the usual form, often twinned, and
attain a large size. Some of the largest are corroded, and others
contain portions of the ground mass. The hour-glass and the
zonal structure are frequent. The felspars belong to the labrador-
anorthite group.

We will now note a few of the interesting cases of variation in
structure of some of the intrusive rocks. The sill in Tideswell
Dale is about 70 ft. thick, and may be divided into five bands or
zones. The central portion consists of a band of coarsely
crystalline ophitic olivine-dolerite, at least 6 ft. thick ; above and
below it are bands of the type with small grains of augite and large
felspars. The lower of these bands attains a thickness of about
II ft. Below it is a margin of fine-grained dolerite about 14 ft
thick. The uppermost band is composed of a similar rock.
The fine-grained dolerite is in a very fresh condition. The
felspars are small and often show signs of fluxion structure.

The upper margin of the Peak Forest sill also consists of a
finer-grained rock than that lower down, though the conditions
for examination are not so favourable as in the case of the
Tideswell Dale rock, which is so well exposed in the quarry.
The junction is concealed by grass. The following differences
have, however, been ascertained. The mass of the rock is a coarse
ophitic olivine-dolerite. In one specimen the augite plates are
small and seldom contain or are penetrated by felspars ; several
prisms of augite are present. This mineral fills the spaces
between the felspars, and the specimen forms a transition between
the ophitic and the granular type. A specimen, one foot below
the junction, consists of a much altered dolerite, in which onljr
altered plagioclase laths can be recognised. It is cut up intcs

THE LOWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 215

separated patches by veins of a secondary silica, which forms a
mosaic like that in the quartz rock of the Top Lift and other
places. The patches of dolerite are also partly siliciBed and
traversed by thin veins of quartz. Crystalline calcite is present.
A specimen 9 in. below the limestone consists of a quartz
mosaic with calcite and probably chlorite, but no dolerite. A
specimen 7 in. below the junction is a much altered olivine-
dolerite, consisting of altered and turbid felspars in laths and
phenocrysts and phenocrysts of olivine, some of which attain a
large size. The spaces between the felspars are probably filled by
chlorite. A specimen 6 in. below the junction is similar to the
preceding, and contains patches of calcite. The rock near the
junction therefore appears to be an olivine-dolerite, which pro-
bably contained augite in grains, and is traversed by veins of
silica. The Pot Luck sill consists of ophitic olivine-dolerite,
which in some places passes into a sub>ophitic dolerite, and in
others into one with granular augite.

The two small dykes which penetrate the agglomerate at
(irange Mill show a slight variation in structure.

The coarser portions of the larger dyke consist of an olivine-
dolerite with granular augite. The olivine is entirely altered, but the
augite and felspar are fresh. The felspars are present in two genera-
tions. A second specimen differs from the first in having smaller fel-
spars. This dolerite is very similar to the rock in the margins of the
Tideswell Dale sill. The smaller dyke is more interesting. The
lower and coarser portions arc a much decomposed olivine-dolerite.
The felspars are turbid and the olivine and augite grains altered
to calcite. The felspars are as large as those in the coarser
portion of the larger dyke. Higher up, the felspars become
smaller, and the rock contains small patches which may be
amygdaloids. A portion of the margin of the dyke, with the
agglomerate adhering to it, consists of mirrolites and small laths
of felspar in a brown and non-isotropic base. They extinguish
parallel with their length and often have jagged ends. The
majority of them are arranged parallel to the edge of the dyke :
probably pseudomorphs of olivine are present. The agglomerate
adhering to the dyke contains small brown vesicular lapilli which
are free from crystals.

The Fracmental KiNKOu^ Roc ks.

The fragmental rocks occur in vents and as bands of tuff
ntercalated with the limestones. It is not always possible to tell
from a hand specimen to which of the two classes a fragmental
rock belongs. The only reliable evidence is that obtained by
examining its mode of occurrence in the field. The interstratified
tuffs are generally composed of laminx varying in thickness and

2l6 H. H. ARNOLD UEMROSE OS

in the coarseness of their component parts, and show frequent
alternations of coarser and finer volcanic detritus. The material
filling the vents often consists of a tumultuous mixture of large and
small blocks of volcanic rock imbedded in a smaller detritus similar
to that found in the bedded tuffs. Both classes of fragmental rock
often contain blocks of dolerite or basalt and of limestone, and
sometimes a large quantity of calcareous material. Lapilli play
an important part in the composition of the whole of the frag-
mental rocks, whether in a vent or bedded tuff. They are
generally minute fragments of a basic pumice, often crowded
with vesicles, and rarely containing a few altered felspars or olivine
crystals. In some cases they are isotropic, and the original
glassy structure is well preserved, but often they are decomposed
and are what has been termed palagonite.

They vary in magnitude from small fragments or shreds up to
about the size of a marble. They have no counterpart amongst
the lavas, i.e., they differ from them in being more glassy, less
crystalline, and contain more numerous and minute vesicles. In
some cases the volcanic detritus consists of small fragments of a
dolerite or basalt. The blocks of igneous rock included in the
bedded tuffs and vents more nearly approach the lavas in structure,
but differ from them in having a more glassy base and a greater
number of vesicles, which are often very small.

Though no complete distinction has yet been made between
the microscopic structure of the bedded tuffs and of the agglom-
erate filling the vents, a few of the differences between them may
be mentioned. The bedded tuffs weather more rapidly than the
material in the vents, though portions of the former may be
obtained which are very hard. The lapilli in the tuffs are nearly
always more glassy and less crystalline than those in the vents,
and the rock more often consists of laminae. There is one case,
if there are not two, in which it is possible to compare the
character of the agglomerate in vents with the tuffs which have
been ejected from them.

The vents at Grange Mill are composed mainly of minute
vesicular lapilli, very seldom containing crystals, and cemented
together with a more comminuted volcanic detritus. No blocks
of dolerite have been found in them, and the only traces of
non-volcanic material are small rounded pieces of limestone,
large angular blocks of the same rock, often marmorized, and a
few pieces of quartz rock. The bedded tuff, of which only the
upper portion is seen, consists of minute lapilli similar to those
in the vent, but much more decomposed. No limestone frag-
ments have been found in it.

The materials composing the vents and the bedded tuffs near
Kniveton and Tissington are different in character from those of
any other locality. All the igneous rocks in this neighbourhood
contain a large quantity of pyrites. The Kniveton vents consist

THE LOWER CARBONIFEROUS ROCKS OF DERUVSHIRE. 217

mainly of more or less rounded blocks of a highly vesicular or
amygdaloidal dolente, the ground mass of which is more glassy
than that of the lavas. The vesicles form a large proportion of
the mass, and the small felspars are arranged parallel to the
boundaries of the vesicles and pseudomorphs of olivine. The
blocks are intimately mixed with, and their vesicles some-
times contain, small glassy lapilli with few traces of crystals ;
a few blocks of limestone are also found. The rocks of Wibben
Hill are similar. The thick bedded ash at Tissington, which may
have been ejected from Wibben Hill or one of the Kniveton vents,
c onsists of glassy vesicular lapilli without crystals, and is entirely free
Trom any non-volcanic detritus. The blocks contained in the tuff
3. re like those in the vents, but, as might be expected, form a
Smaller proportion of the rock. The smaller intercalations of
^ uff are similar to the thick tuff bed, but contain very few and small
ejected blocks, and are mixed with varying amounts of fossils and
^^alcareous material.

The Hopton agglomerate differs from that in any other vent.
S^ t is a breccia, consisting of angular fragments of a glassy basalt
^^enaented by small lapilli and calcite. The fragments are distin-
.^^uished not only by their angular shape, but also by the very
•"resh condition of the augite and felspar contained in them.
^K^elspar and augite fragments occur in the calcite-cement, and
^:^locks of limestone are absent. In some parts the lapilli are
^silicified.

The agglomerate of Ember I^ne is distinguished by the very

arge proportion of limestone fragments and calcareous material

"^rhich are intimately mingled with the lapilli. The differences

^^Detween these agglomerates are so well marked that it is possible

%o tell whether a hand specimen is from Kniveton, Grange,

Slopton, or Ember Lane.

With the exception of the Speedwell vent, near Castleton,

^he fragmental material in the remaining tuffs and vents nearly

approaches those of Grange Mill in structure. The lapilli in the

Speedwell vent are seldom vesicular, often contain felspar and

divine pseudomorphs in a dense black or yellow matrix, very

^^nuch like tachylite. More minute details of the microscopic

structure of the fragmental rocks of the district will be found in

'^he papers by the author, to which reference is made at the end of

^his Sketch.

Mountain Limestone.

Very little work has been done in the microscopic examination
of the finer-grained varieties of the Mountain Limestone of
Derbyshire. Dr. Sorby examined a number of thin sections of
Carboniferous Limestone from England and Scotland, but the
greater portion of his specimens were from Derbyshire and the

2l8 H. H. ARNOLD BEMROSE ON

neighbourhood of Bristol. His results, therefore, are in the main
probably true for the rocks of this county. He found that
" though there is a considerable variation in different specimens,
yet on the whole there can be no doubt that by far the greater
part of the identifiable fragments are joints of encrinites, often
entire, but sometimes broken. Next in amount are fragments of
brachiopoda, and then entire or broken foraminifera, which not
infrequently are as important a constituent as they are in most
specimens of chalk. The bulk of the recognisable fragments of
corals and polyzoa is on the whole somewhat less but occasionally
very great. Shell prisms are also present in considerable
quantity."

The author has collected a number of thin sections, but up
to the present has not been able to examine them in detail. The
following brief notes, though they are only of the nature of an
introduction to the subject, may be of interest. The specimens
have been taken from different localities and horizons, but it is
impossible to say how far they are typical of the whole of the
limestones. A specimen from near Windy Knoll, given to the
author by Dr. Wheelton Hind, appeared to be oolitic, but a
thin section showed that it consisted of fragments of corals and
other organisms, and small limestone pebbles containing a
few quartz crystals. The structure was partly obliterated by
alteration of some portion of the slide to crystalline calcite, and
no oolitic grains w^ere present.

The limestone above the bedded tuff near Grange, also above
the tuff at Litton, and in many localities, weathers into small
nodules. Examined with a lens, the rock is seen to be made up
of small grains, which, however, are not oolitic, but are composed
of fragments of brachiopoda, corals, encrinite stems, forami-
nifera, and other organisms, and also of irregularly shaped pieces of
a previously consolidated limestone. These fragments of lime-
stone frequently contain foraminifera, and other small fossils, and
sometimes a few bipyramidal quartz crystals. The fossil and
limestone fragments are often more or less rounded. This
granular structure is, however, not confined to the nodular
variety, but forms large portions of the massive beds of the
Mountain Limestone. Girvanella has been found in one or two
localities.

In the thin ashy limestones near the base of the Yoredales at
Tissington were found worn shell fragments and small pieces of
a previously consolidated limestone, sometimes containing a few
quartz crystals. The limestone frequently contains well preserved
foraminifera in such numbers that the rock is to a great extent
composed of these organisms. Very few specimens of the lime-
stone when examined microscopically have been found to contain
grains with oolitic structure. The black or dark coloured fine-
grained limestones, which are found in the lower Yoredales, and

THE I.OWER CARBONIFEROUS ROCKS OF DERBYSHIRE. 219

in some of the upper beds of the Mountain Limestone, generally
consist of a more or less crystalline calcite, with a black or brown
material between the small grains. Sometimes a few traces of
organisms are present.

Marmorized Limestone.

The limestone which has been completely marmorized is
generally white, has a translucent surface when wet, breaks with a
saccharoidal fracture, and is easily crushed into a white crystalline
powder. It consists of crystalline grains of calcite, which give
the usual cleavage lines and interference colours under the
microscope. No crystalline silicates have been found in it.

DoLOMiTiZED Limestone.

Some of the beds in the Mountain Limestone are, as Dr.

Sorby remarks, almost pure dolomite. He was able tojjrove, by

selecting a specimen in which the alteration was incomplete, that

the organic fragments had been changed into dolomite. At the

same time he considered that " it is possible, and even probable,

that a considerable part of the deposit originally contained a

large amount of magnesia, since the dolomitic beds have a

considerable horizontal extension, and are interstratified with

rock of the usual type." A section cut from a specimen

of dolomitic limestone from the Cumberland Cavern at

Matlock was described by Mr. Rutley as consisting entirely

of small rhombohedra of dolomite. His analysis ** showed

it to be almost identical in composition with the typical

dolomites of the magncsian limestone series, the calcium

Carbonate amounting to 51 '25, and the magnesium carbonate

to 42*18 per cent., the remainder consisting mainly of silica with

a. little iron alumina and water." He found that after dissolving

the rock in hydrochloric acid the residue consisted of " minute

t^hombohedra, some of which were considerably and others

^lightly eroded, whilst many exhibited perfectly sharp angles and

^^dges. The thin sections examined by the author do not

c^ften show the forms of the rhombohedra so clearly. The

grains are more irregular in shape and fit closely together. Some

specimens are composed of very small grains of dolomite, whilst

Slithers have a very coarse crystalline structure. The dolomite

grains sometimes contain patches of crystalline silica and quartz

^lirystals, the largest of which seen measured 40 by 25 mm.

SiLiciFiED Limestone.

The silicified limestone or quartz rock is a granular rock with
Sometimes a black or dark brown material between the grains.
XTnder crossed nicols it appears as an aggregate of quartz grains,

2 20 H. H. ARNOLD IJEMROSE OX

the majority of which are elongated in the direction of the
least axis of depolarisation. They attain a length of 1*25 mm.
They seldom have crystalline outline, but closely interlock and
penetrate one another. A few of them are hexagonal in cross
section. The rock often contains fluor in irregularly shaped
masses and small cubes. The quartz in the quartzose limestone
occurs in veins and small patches similar in structure to the
quartz rock, and also in separate crystals with bipyramidal
terminations.

The siliceous rock largely quarried at Bakewell consists of a
micro-crystalline quartz mosaic, and often passes into a crypto-
crystalline structure which contains small patches of the
former. The threads of silica which traverse the rock are
composed of a mosaic of clear quartz grains, which have no
crystalline outline, and are not elongated.

REFERENCES

One Inch Ordnance Survey Maps, 99, in, 112, 124, and 125. (is. each.)
Geological Survey One Inch Maps:

71 N.W. Crich (1867. 3s.)

72 N.E. Ashbourne (1868. 3s.)
81 N.E. Castleton (1866. 3s.)

81 S.E Taddington, Miller's Dale (1867. 3s.)

81 N.V\'. Includes Hayfield only (1864. 3s.)

82 SW. Matlock (1866. 3s.)

4 -inch Index Map, Sheet 8. (2s. 6d.)

Geological Survey Memoir, N. Derbyshire.

(This gives a Bibliography of Derbyshire Geology from 1653 to 1887.)

1778. Whitehurst, J. — '* An Enquiry into the Original State and Formation

of the Earth," etc. 4to. London.
1811. Farev, J. — "A General View of the Agriculture and Minerals of

Derbyshire," vol. i. 8vo. London.

1874. Allport, S. — " On the Microscopic Structure and Composition of

British Carboniferous Dolerites." Quart. Journ. Geoi,Soc,y vol. xxx.
pp. 551, 552.

1875. Pennington, R. — "On the Bone Caves in the neighbouroood of

Castleton. Derbyshire." Quart. Journ. Geoi. Soc. vol. xxxi., p. 238.
1877. Dawkins, Prof. W. B., and Pennington, R. — '' The exploration of
the ossiferous deposit. Windy Knoll, Castleton, Derbyshire." Quart.
Journ, Geol. Soc.^ vol. xxxiii., p. 724.

1870. Brown, E. — *'On a columnar clay-bed in Tideswell Dale, and so-

called Pholas borings in Miller's Eteile." Geol. Mag.^ vol. vii., p. 585.
Wilson, E. — •' Altered clay-bed and sections in Tideswell Dale, Derby-
shire." GeoL Mag.^ vol. vii., p. 520.

187 1. Mello, Rev. J. M. — **On an altered clay-bed and section in Tideswell

Dale." Quart. Journ. GeoL Soc.j vol. xxvi., p. 701.

. — Handbook to the Geology of Derbyshire. Second

Edition.

1879. SORBV, H. C. Anniversary Address to Geological Society.

1880. Stokes, A. H. — " Lead and Lead Mining in Derbyshire." Trans.

Chesterfield and Derbyshire Inst, Eng.^ vol. viii., pp. 60, et seq.

221

i888. Tball, J. J. ll,^BntisJk Pgirogra/fy.pp. 209, 210, and Plate IX.
1894, ARNOLi>.BBifROSK, H.— "Notes on Crich Hill." Joumalo/ikg Dtrhy
Arclueologkal tmd Nat. Hist, Soc,

1894. . — " On the microscopical structure of the

Carboniferous Dolerites and Tuffs of Derbyshire.** Quart, Jomm,
Geoi, Soc.^ vol. l,pp. 603-644, I pL
1 896. Bashes, J., and Holroyd, W. F.— ** The Mountain Limestone caverns
of Tray Cliff Hill, Castleton, Derbyshire, with some of their
contained minerals.*' Trams, Matuhester Geoi. Society, Part X,
vol. xxiv.

. — "On the occurrence of a Sea

Beach at Castleton, Derbyshire, of Carboniferous Limestone age."
Trams, AfoMcJk. Geo/. Sbc,^ vol. xxv, pp. 1 19-125, 4 pi., 1897.

-Further notes on the Soi Beach in Carboniferous Lime-

stone. Derbyshire, /SiJ.y pp. 18 1- 1 84, I pi., 1897.

-. — Reply to Professor Hull's criticism on the papers,

"A Sea Beach at Castleton.*' /6ut., pp. 308-310, 1897.
1897. Hind, Dr. Wheelton. — "On the subdivisions of the Carboniferous

series in Great Briuin, and the true position of the beds mapped

as the Yoredale series.'* do/. Mag.^ April and May, 1897.
1897. . — "Section in Carboniferous Limestone

shales at Tissington." Nortli Staffords/iire Fittd Ciub Report^

vol. zzxii, I pi.

1897. Geikie, Sir Archibald. — "Ancient Volcanoes of Great Britain,"

vol. ii, pp. 8-22.

1898. Arnold-Bemrose, H.— "On a Quartz Rock in the Carboniferous

Limestone of Derbyshire.*' Quart. Journ. Geoi. Soc.^ vol. liv, pp. 169-

182, 2 pi.
1 899. . — " Geology of the Ashbourne and Buxton

Branch of the London and North Western Railway (Ashbourne 10

Crakelow)." Quart. Journ. Geoi. Soc., vol. iv, pp. 224-236, 2 pi.
1899. . — "On a Sijl and Faulted Inlier in Tideswell

Dale (Derbyshire)." Quart. Journ. Geoi, Soc.^ pp. 239-249, 2 pi. and

sections.

LONG EXCURSION TO DERBYSHIRE.

Wednesday, August 2Nd, to Thursday, August ioth,

1899.

Directors'. H. Arnold Bemrose, M.A., F.G.S., Wheelton
Hind, M.D., B.Sc. Lond, F.R.C.S., F.G.S., J. H.\rnes,
F.G.S., G. E. Coke, F.G.S., and Prof. Carr, M.A., F.L.S.

Ejccurshn Sicrtimry : Frederick Mkeson.
(Reportby H. Arnold Bemrosb and VVheklton Hind.)

The object of the excursion was to study the Lower Carboniferous
rocks of Derbyshire. The visit to the Mill Close Lead Mine, and
the excursion to Nottingham were added to the usual seven days
excursion. The number of members attending the excursions
xaried from fifty-two to sixty-nine. The headquarters of the
pany were at the Royal Hotel, Matlock Bath.

November, 1899.] 17

222 LONG EXCURSION TO DERBYSHIRE.

Wednesday^ August 2nd, Directors : H. Arnold Bemrose
AND G. E. Coke.

In the afternoon a visit was made to the Mill Close Lead
Mine. Through the kindness of Mr. Alsop, every facility
was given for the descent of the party, which numbered thirty-
eight. Six members went down the shaft which is being sunk in
the Toadstone. A thin seam of coal in the Mountain Limestone
was seen in the mine. The remaining members visited those
portions of the mine which were in full work. They saw
the junction of the limestone with the overlying shales, and the
manner of occurrence, and the method of obtaining the ore, and
on returning to the surface were shown the process of washing and
separating it. The plans of the mine, and the very good
collection of lead ore, calcite, fluor, and other minerals were
examined with great interest. Afternoon tea was provided by the
kindness of Mr. Alsop, and the party returned to Matlock by
carriages.

Thursday, August jrd. Director: Wheelton Hind.

On alighting at Hayfield Station, the road lay over the
upper beds of the Millstone Grit and the intervening shales,
along the Kinder Stream towards Kinder Scout. Arrived at the
S.W. flank of the hill, on a plateau formed by the fifth bed
of grit known as Farcy's Grit, the equivalent of the Pendleside
Grit, the Director indicated the chief features of the landscape
formed by beds of the Third, Fourth, and Fifth Grits and
the intervening shales. The top of Kinder Scout consists of
a plateau of some extent, formed by the almost horizontal beds
of the Fourth Grit, covered by deep beds of peat ; but the rocks
appear weathered into fantastic shapes along the edges of the hill.
Descending by Edalc Cross, across the shales below the Fourth
Grit, Farey*s Grit and its shales were passed over in succession,
and special attention was called to a bed of large " bullions "
or concretions in the stream at Barber Booth, which the Director
considered an important horizon, mapable throughout North
Staffordshire, Cheshire, Derbyshire, South-east Lancashire, and
South-west Yorkshire, containing a rich fauna which passed up
into the Gannister Beds of the Coal Measures, but not passing
down into the Carboniferous Limestone.

The Edale Valley was then crossed, the same beds bein<< seen
in stream sections on both sides, and an ascent made to Mam
Nick, the entrenched camp on Mam Tor being noticed. At
Windy Knoll, the cavern explored by Prof. Boyd Dawkins
and others, which had yielded a rich mammalian fauna, was noticed,
and the bed of elaterite and vein of fluor-spar in the quarry
examined and collected from. Specimens of oolitic limestone,
and limestone containing limestone pebbles, were examined from

LONG EXCURSION TO DERBYSHIRE. 22$

the walls, though the bed was not seen in situ. Passing down the
gorge of the Winnats, some of the party stayed to examine the
Speedwell Mine ; also a bed of rolled shell-fragments indicating a
contemporaneous beach, or a bed subject to wave action, the
horizon of which is at the top of the " Massif" of Limestone. A
▼isit was paid to the Great Peak Cavern, and the stream of under-
ground water passing through it was noted.

W. H.

Friday^ August 4th, Directors : H. Arnold Bemrose,
Wheelton Hind, and J. Barnes.

The day's work began with the examination of the fossiliferous
quarry at the bottom of Cavedale, the horizon of which is
practically at the top of the Limestone. Two sections showing
the rolled shell bed were visited, and another fossiliferous quarry
on the same horizon at the mouth of the Odin Mine.

From this point a description of the physical features of the
district was given, and then the shales containing Fosidoniella
lavis^ Aviculopecten papyraceus and Goniatites were examined,
and the section of Mam Tor noted. The contact of limestone
and shales was seen in a stream, but the Director pointed out that
the shales had probably slipped.

W. H.

At the foot of the Winnats, Mr. Arnold Bemrose drew
attention to the agglomerate near Goose Hill Hall, and pointed
out how the igneous rock cut across the beds of limestone, and
the reasons for considering it to be a vent.

The Blue John mine was next visited, where The Ladies
Walk, the Grand Crystallised Cavern, Lord Mulgrave*s Dining-
room, and other interesting features of the mine were kindly
described by Mr. J. Barnes. (See p. 179.)

A detour to the village of Peak Forest was then made. Mr.
Arnold Bemrose led the way to a small mass of intrusive
dolerite which has been exposed by denudation in Dam Dale.
The variation of the sill from a coarse ophitic dolerite to a
fine-grained dolerite near the upper margin, and the very perfect
marmorization of the overlying limestone, due to the contact of
the igneous rock, were pointed out.

Barmoor Quarry was examined, with brecciated limestone and
beds with fish teeth. Mr. Smith Woodward gave an interesting
account of the fish from these beds, and Psephodus and
Psammodus were obtained. Passing the Ebbing and Flowing
Well, a halt was made in the cutting in the limestone along
the tramway, where the actual sequence of limestone and shales
is to be seen, the shale with ** bullions " occurred higher up in
the cutting of the Manchester and Buxton Railway.

W. H.

224 LONG EXCURSION TO DERBYSHIRE.

Saturday, August sth. Director : H. Arnold Bemrosk.

The party proceeded to Miller's Dale by train. The route
taken was down the valley of the Wye as £9ir as Tongue End, and
then up Tideswell Dale to TideswelL The lava exposed in the
bottom of the valley was examined and good junction specimens
of the lava and overlying limestone were obtained at Rancher
Tor. A considerable time was spent in Tideswell Dale in order
to examine the faulted inlier of Mountain Limestone containing a
sill intruded between lava-flows. Evidences for the faults and for
considering the ophitic dolerite to be intrusive were pointed out
in detail. Specimens of baked clay, marmorized limestone, of
the igneous rock, and Lithostrotian junceum, Lithostrotian irregu-
iare and Dibunopyllum were obtained. In the quarry, Mr. £. T.
Newton gave a short address on the corals found in the Carboni-
ferous Limestone. After lunch at Tideswell, the party walked to
Litton to see the laminated tuff contemporaneous with the lime-
stone. A very good coral bed was seen in the quarry near Peep-
o'-day. A return to Miller's Dale was made by carriages ; and
(through the kindness of Mr. Brierly, Director of the Buxton
Lime Firms Co., Ltd.) the section near the Station was examined.
Tufaceous limestone with a small lava-flow, coarse bedded tuff
and a larger lava-flow, were seen intercalated with the limestone.

Monday^ August Tth. Director: H. Arnold Bemrose.

The party drove to Cromford Station, and examined the shales
with limestones. Posidoniella was found in the shales, and a
gasteropod from one of the nodules of limestone. The quarry
at Cromford in the upper cherty- and Productus-heds of the
Mountain Limestone was visited, and Productus giganteuSy Pro-
ductus hemispttaricuSy Streptorhynchus crenistria, a coral, and the
tail of a Phillipsia were found. The Black Rocks composed of
Kinder Scout Grit were next climbed, and a fine view of the sur-
rounding country was seen. The party drove vid. Middleton and
Ryder Point to Grange Mill. The bedded tuff at Shothouse Spring,
and the vents of agglomerate near the Mill with two or three dykes
were carefully examined, and the evidence of their origin discussed.
The party proceeded down the Via Gellia examining the cal-
careous tufa quarry and walked up the hill through Bonsall to
Pounder Lane. The members here examined the quartz rock,
quartzose limestone, and agglomerate of Ember Lane, and
returned over Masson Hill to the Hotel.

Tuesday, August Zth, Director: H. Arnold Bemrose.

The party drove to Tissington, and on the way a halt was
made at Hopton to see partially dolomitized limestone, and a
neck of coarse volcanic agglomerate with several small dykes.
On arriving at Tissington, the party walked along the New Kail-

EXCURSION TO NOTTINGHAM. 225

way (by kind permission t)f the L. & N. W. Rly. Co.) and were
accompanied by Mr. W. Hurst, the resident engineer. Sections
in contorted and tufaceous Yoredale shales and limestones, and
also the thick bed of tuff which in one place is exposed from top
to bottom, were seen in the first cutting. Similar beds were seen
in other cuttings as far as Crakelow, and in the latter cutting
the thick tuff-bed was seen to be faulted against the Mountain
Limestone. A climb to Crakelow Quarry was made, where
nearly every bed of limestone is tufaceous. The rapid variation
of the beds and intercalations of tuff were pointed out, and
fossils were found in one bed of tuff. The party then walked to
the Peveril Hotel, Thorpe, and after tea they returned to Matlock,
vi& Longcliffe. The castellated weathering of the dolomitized
limestone was remarked ; and near Longcliffe Wharf Station on
the High Peak Railway, at a height of 1,050 ft, a halt was made
to visit an interesting sand and fire clay pit in a hollow in
dolomitized limestone.

After dinner the hearty thanks of the Association were
given to Mr. Bemrose, Dr. Wheelton Hind, Mr. Barnes and others,
who had contributed so largely to the success of the excursion.

Wednesday^ August ^th. Director: H. Arnold Bemrose.

The party went by train to Ambergate and walked to Cnch
to see the faulted inlier and dome-shaped mass of Mountain
Limestone. They were accompanied by Mr. Boag, the Manager
of the Clay Cross Co.'s Works. The evidence for the three
faults was fully explained. Some time was spent in the quarry in
obtaining fossils, and several minerals. The bed of shale, some
220 ft. down in the Mountain Limestone, on which the landslip
took place some years ago, was energetically examined for fossils.
The Hill was climbed, the chasms due to the slip being passed on
the way. From the summit of the Stand, or Tower, a fine view
of the surrounding county was obtained. The descent to Wake-
bridge was made and the shales in the brook-course seen. The
party then proceeded to Whatstandwell through quarries in the
Millstone Grit. A pebble of foliated igneous rock found in the
grit was obtained from a quarry man. It measured nearly
6 inches in length. The party returned to Matlock by train.

EXCURSION TO NOTTINGHAM.

Thursday^ August loth. Directors : G. E. Coke and
Prof. Carr.

{Rtport by F. Meeson.)

Thirty-five members left Matlock Bath for Nottingham.
They then divided into two sections, one of which consisting
of twenty-five members accompanied Mr. Coke, and through
November, 1899.]

226 EXCURSION TO WELDON, DENE, AND GRETTON.

the kindness of the Clifton Colliery Co., inspected the
coal mine at Clifton Colliery, and then went on to Thurgarton.
The other section accompanied Prof. Carr to the brickyard
on the west side of Bulwell, where a section of the Middle
Permian Marls, about 30 ft. thick, was seen resting upon the
Lower Magnesian Limestone. The Permian Marls passed
upwards without apparent break into the Lower Mottled Sandstone
of the Trias. A quarry a little to the north of the brickyard was
next visited, where the Lower Magnesian Limestone, about 30 ft
thick was seen. The party next drove to Kimberley to examine the
section exposed in the excavation for the Great Northern Railway
Station. This section shows at the top the Ix)wer Magnesian
Limestone resting upon the Marl Slate, at the base of which is a
hard compact breccia about 3 ft. thick, composed of fragments
principally of Carboniferous rocks in a calcareous matrix. This
breccia forms the base of the Permian in Northamptonshire, and
rests with a marked unconformity upon the upturned edges of the
Middle Coal Measures.

After arrival at Thurgarton, both sections walked a short
distance to the borehole which is being put down by Messrs.
Barber, Walker & Co., as a trial for coal. The cores from the
Trias and Permian formations were inspected by the party, and
the boring machinery was explained by Mr. Coke. Mr. Shipman
met the party and made a few remarks on the geology of the
district.

The President thanked Messrs. Barber, Walker & Co., on
behalf of those present, for the permission to visit the borehole ;
and Mr. Coke for the assistance he had rendered in organising
the supplementary excursions.

EXCURSION TO WELDON, DENE, AND GRETTON.

Saturday, April 29TH, 1899.
Director. Beebv Thompson, F.C.S., F.G.S.

ExcurtioH Secretary : Bedford McNeill, A.R.S.M., F.G.S.
{Report by The Director )

The excursion was arranged in order to examine the whole of
the strata comprising the Inferior Oolite in the area embraced.
The sequence of beds will be best seen on reference to the
accompanying diagram of comparative sections.

Weldon and Corby Brickworks was the first section visited.
The clay worked here belongs to the upper part of the Upper
Lias, and embraces a part of two zones, the Upper Leda-avum-
Beds {/urensis zone of Thompson ; Lilii hemera of S. S, Buck-
man), and the Middle Leda ovum-Beds (a part of the A, com-
munis zone). There is a false junction between the Upper Lias
Clay and the Northampton Sand owing to the slipping of the
November, 1899.]

EXCURSION TO WELD03€, DEXE, AXD GRETTOST. 227

latter over the former ; abo, it was noted that the clay itadf «as
thrown into a sharp IbkL a result doe, no doubt, to the slipping
of the day itsdf towards the vaDey.

Only a few fosals were obtained, but the visitors were shown
tbehead ofa 72s6«iaai9«f diat had bm foandqoite recen^^ A
few years back a £uiiy complete skeleton of an JdUkfcsamwms^
23 ft in length, was tbond hoe, and is now in the Northampton
Museum.

The Iromsiome TPcrikimgs near the brickworks, and dose to
the village of Corby, were next examined, and attention was
particiilarly directed to the Chalky Boulder Clay (a) with large
enatics and scratched bkx^ resting on the Lower Estoarine
Beds (5 to 8).* The Estoarine Beds are very varable in
character, alternations of vertical and horizontal carbonaceous
markings being frequent. In No. 6, horizontally bedded car-
bonaceous matter occurs near the bottom. In No. 7, the first
foot or so is a good day with very numerous, black, horizontal
lines of carbonsKreous matter ; bdow this, however, the bed is
more sandy and the carbonaceous matter irregularly disposed.

Weldatu — Some disused ironstone workii^ to the north of
Weldon Grange were next visited, in order to observe the
continuity of the various beds seen at Corby, and the changes in
some of them. The whole section embraced beds 4 to 9. Here,
as at Corby, there is an irregular junction between beds 7 and 8.
The total thickness of the exposed beds is very near to the total
thickness of the correspondii^ beds at Corby. \ considerable
K. to S. fault near here lets down all the beds to the east, so
tihat the ironstone in that direction is too deep to work, even if it
^^rere suitable.

Great Weldon Stone Quarries. — The noted freestone
c^uarries at Great Wddon, owned by Lord Winchilsea, were next
inspected, by the courtesy of Mr. John Rooke, under the
^[uidance of the foreman of the works. The stone varies a good
deal, and much has to be wasted, but when well selected it
furnishes a very beautiful stone for ornamental work, of a pleasing
^x>lour and good wearing qualities. The total thickness is from
30 to 25 ft- (For fiill description see Sharp, "Oolites of
l^forthamptonshire," Quart, fourn. Geol. Soc.^ vol xxix, p. 234.)

Just outside Wddon is a small roadside section in probably
the highest beds of the Lincolnshire Oolite. It is an oolitic rock
abounding in fossils, particularly gasteropods. Weldon as a
source of Lincolnshire Oolite fossils will be better appreciated on
reference to Mr. Hudleston's " Monograph of the British Jurassic
Gasteropoda " (Ptdnontographkal Society).

Weldon to Dene. — Between Weldon and Dene, in the valley
to the south of the road, a small section was examined, showing
a very light coloured clay or marl resting directly upon a shelly

* The %Dffcs rder to diagram of comparathre sectiocs, pu %yx.

228 EXCURSION TO WELDON, DENE, AND GRETTON.

limestone, almost exactly like that seen a little previously near
Weldon, thus fixing the position of this particular zone in this
area. The clay represents the Upper Estuarine Beds of the Great
Oolite.

Dene, — The section at Dene has been described in three of
the works quoted in the list of references, but as none of these
correlate the beds with others in the district, or quite agree with
the observations of the Director, another is here given. The
larger figures refer to the diagram of comparative sections, the
smaller to Prof. Judd's description ("Geology of Rutland,"
Mem, GeoL Survey ^ pp. loi, 102).

ft. io.

^ 3. I. Marly limestones i to 2 o?

, 2. Whitish, calcareous sands I 6

3. Hard, blue-hearted, sub-crystalline limestone i 6

4. Brownish, calcareous sand, becoming indurated into
stone at the base ... 2 o

5. Hard and compact coralline limestone, full of Nerituta^
with partings of clay 3 o

6. Irregular bed of silicious concretions with mammilated
2 ^ surfaces below. This bed intensely hard ; between
*^ its laminsc are numerous plant remains ; it appears

to be the representative of the Colly weston Slate
(Judd) I o

4. 7. Irregularly stratified and false-bedded variegated sand
(6 to 8 ft.— Judd)

In places almost passes into stone. Intimately
connected with No. 3 (6), and at one place rising
into it a good deal, therefore thickness variable ... 6 o?

6. [Absent]

6. 7. Light bluish sand, getting much whiter on exposure,
with abundant vertical plant markings 3 o

7. 8. Dark carbonaceous, sandy clay, with masses of iron
pyrites, and fragments of wood converted into iron
pyrites 5 o

9. Bed of hard sandstone of a dark grey colour (" Kale "

of the workman) I o

8. 10. Light coloured sandy clay 3 o

9. II. Sandy ironstone (dug in a well), 3 to 4 ft 40?

10. 12. Upper Lias Clay

Evidences of Unconformity. — In a set of beds characterized
by an abundance of carbonaceous matter, and therefore of shallow
water or estuarine origin, one need not be surprised at evidences
of unconformable succession anywhere in the series. The
irregular junction between beds 7 and 8 at Corby and Weldon
may be taken as evidence of denudation at those places. The
horizontally or irregularly-bedded carbonaceous matter in No. 7
and the lower part of No. 6 may be looked upon as evidence of
continued erosion not far away.

At Dene, erosion appears to have cut out the whole of
Bed 5 and the upper part of Bed 6, as the junction between 4
and 6 is irregular ; moreover, the lower part of No. 4 contains

in.

^EXCURSION TO WELDON, DENE, AND GRETTON. 229

much carbonaceous matter more or less horizontally bedded,
probably through the disturbance and re-deposition of the upper
layers of No. 6, in which latter the carbonaceous matter is
vertically disposed.

For these reasons and others connected with the examination
of sections not included in the excursion, bed No. 4 has been
placed with the Lincolnshire Oolite and not with the Lower
Estuarine series as it is by Professor Judd and Mr. H. B.
Woodward.

It is usually assumed that the Lincolnshire Oolite (Beds 2 to
4) was never deposited in the Northampton area, and that there
was considerable denudation of the Lower Estuarine beds ; the
former assumption is probably correct, and the latter requires
some modification. A typical section of the Estaurine beds near
Northampton would be as below : *

6. I. White or bluish grey sands, with some argillaceous |

matter ivith vertical plant markings, particularly -
in lower part )

7. 2. Orange and yellow sands. No plant markings

8. 3. Sands almost exactly like No. i, with vertical plant

markings even more abundant

When we compare i, 2, and 3 with beds 6, 7, and 8 at Corby,
Weldon, and Dene, and see that collectively and individually they
so nearly correspond in thickness and character (oxide of iron
replacing iron pyrites in the middle one), it is scarcely possible to
avoid the conclusion of their correspondence. It would thus
appear that around Northampton denudation was not greater
than at Dene.

Kirby Slate Quarries have not been in work for a great many
^ears, but still the position of the slate beds relatively to the
limestone series could be inferred from the nature of the
excavation. Specimens of the slate itself were found where the
working of it was formerly carried on. The slate usually consists
of a single band of stone in the sandy beds (4), or it may, as at
CoIl3rweston, constitute the whole of that lithological division.

Kirby and Dene Lodge are the most southerly points at
nrhich slate has been worked for roofing material.

Gretton, — At Gretton the ironstone workings were examined,
t>ut here the Estuarine beds are absent, the ironstone either comes
to the surface or is capped by Boulder Clay. The beautiful view
icross the Welland valley into Rutlandshire received appreciative
ittention.

Tea was provided at the Hatton Arms Hotel at Gretton,

•S«e "Excursion to Northampionshire^" /*r«:. Geol. Assoc,^ vol. xii, November, 1891
Diagram and page 184), also " The Oolitic Rocks at Stowe*nine-Churches," by Beeby
rhompaon, F.C.S., F.G.S., ]oum. Northamptonshire Nat, Hist. Soc., No. 48, vol vi,
Jeoetnbcr, 189Z.

230 EXCURSION TO WELDON, DENE, AND GRETTON.

COMPARATIVE SECTIONS.
Corby. Weldon.

Boulder Clay,

with chalk, flints,

and scratched

blocks.

Dark-blue Clay.

White and Red

Sand.
Vertical plants.

4 5

3' 6"

Clay or Marl.

Oolitic

Limestone.

Highly fossil-

iferous.

Weldon Stone.

Quarried for

building

purposes.

White, Red, and
Orange Sand.
Very variable.

Dark-blue Clay.

Sand and Argill-
aceous Matter.
Vertical plants

and iron pyrites.

Dark Carbon-
aceous Clay.
No vertical
plants.

White and Red

Sand.
Vertical plants.

Ironstone,

quarried for

smelting.

Blue Clay.
Lilli-zone.

Blue Clay.
Communis-zone.

10'
to

12*

Dark Carbon-
aceous Clay.
Much wood.
No vertical
plants.

White and Red
Sand.

Dene.

Upper Estuarine Beds.

Ironstone.

(Not in work).

Exposed to

about 7 feet.

20'
to
25'

o
O

3' 6"
to
4'

3'
to
6'

^•y^^'^^r*^^^^^'^^^^^

to?

12'

Limestone.

Lincolnshire

Oolite.

Siliceous
concretions.

Variegated
Sand,

irregularly
stratified and
false bedded.

White and

Bluish-white

Sand.

Vertical plants.

Dark Carbon-
aceous Sandy
Clay,

with wood.

Iron pyrites.

" Kale."

Light-coloured
Sandy Clay.

loT

6'?

9 Sandy Ironstone.

Upper Lias

EXCURSION TO BRITl'ANY. 23!

Lnd most of the party departed by the train leaving Gretton at
>.28 p.m.

REFERENCES,
ideological Survey Map, Sheet No. 64.

873. Sharp, Samuel. — "The Oolites of Northamptonshire.*' Quart,

Journ. Geol Soc.^ vol. xxix, p. 225.
^875. JUDD, John W. — " The Geology of Rutland," etc. Mem. Geol,

Survey.
1886-96. HUDLESTON, W, H. — "Monograph of the British Jurassic

Gasteropoda." Palaontographical Soc.
1887. Woodward, Horace B.— " The Geology of England and Wales."

Second edition.
1893. — — . — "The Jurassic Rocks of Britain," vol.

iii. Mtm. Geol. Survey.
1893. . — "The Jurassic Rocks of Britain,*' vol. iv.

Mem. Geol. Survey.

EXCURSION TO BRITTANY.
Whitsuntide, May iSth to 24TH, 1899.
Director : Charles Barrois, D.Sc, For. Memb. G.S.

ExcurtioH Secretary : W. P. D. Stbbbing, F.G.S.
(Report by Dr. Barrois, Translated by R. S. Hbrries.)

Thursday^ May i8ih. — The party started from London on
May 17th at 8.5 p.m., arriving at St Malo at noon, when the ladies
were all on deck ; and the gentlemen were soon employed in
making the acquaintance of the French custom house officers.
However, in spite of the special facilities arranged for, the train
was missed, and Dol was not reached till two hours after the
appointed time, a delay which made it necessary to leave St
Marcan out of the programme.

Dol was known in Roman times as Campi DoUntes^ but the
name is evidently the Celtic word dol — low-lying, a dale, Dol is,
indeed, a low-lying place, built on the old Post-Pliocene shore.
The coast about Dol has undergone many changes, and from Dol to
Mont St Michel there is a low and marshy shore, where stand small
isolated granitic hills, which have resisted marine denudation
better than the surrounding Brioverian shales. The shales are
covered by Recent and Quaternary beds, forming a great
plain round Mont Dol, which, as well as Mont St. Michel, was
an island before the eighth century. It has been calculated that
the rate of deposit of sand and silt in this bay has been 16 million
cubic feet a year. This marine deposit, which was, to a large
extent, reclaimed from the sea by the industry of the inhabitants,
was accumulated between the third and eighth centuries. It
consists of fine, bluish grey, calcareous clays, with remains of
marine shells, which are used for putting on the land. Below is
November, 1899.]

232 EXCURSION TO BRITTANY.

Alluvium some sixteen feet in thickness with thick beds of
peat containing trunks of trees. These peat beds are earlier than
the third century, and rest on a grey, compact, calcareous clay, a
kind of marine silt belonging, in all probability, to the age of the
reindeer.

The Pleistocene period is represented on the coast by raised
beaches, which reach a height of about 40 ft. At the disused
brickyard at Mont Doli visited by the party, 800 teeth of Elephas
primigenius have been found, and are now preserved in the
museum at Rennes. Inland the Pleistocene is represented by
valley gravels over which is a fine yellow homogeneous loam
which is only found on the Channel side of Brittany.

Below these Drift deposits at Dol, are found the crystalline
rocks which formed the ancient Pleistocene cliff, well seen inland
towards St. Broladre and Roz-sur-Couesnon. They consist of
blue shales with beds of grey greywacke, of Brioverian age, which
have been rendered spotted, nodular, and micaceous by the
proximity of the granitic mass of St Marcan.

In the midst of these shales, which cover a large area from
Pl^n^e-Jugon to Bazouges-la-Perouse, certain round bosses of
granite stand out, such as Mont Dol, which was visited by the
party, and Mont St. Michel. For a description of these, and an
account of their diversity in structure and composition, see p. 1 17,
and Fig. 10, p*. 118.

At Mont Dol some fine dykes of ophitic diabase are to be seen,
varying in thickness from 3 to 30 ft., such as are scattered over
this district, as shown on the geological map. The number of
these dykes of Carboniferous age in the neighbourhood of St.
Malo is so great that the country must have been covered with
continuous outflows of diabase, similar to the basaltic sheets of
recent volcanic plateaus. Subaerial denudation has left no trace
of this covering.

Near Dol is a famous Menhir, about 30 ft. high and still
standing upright ; it is situated in a field called '* Champ Dolent "
distant one mile and a half from the town. The party, before
leaving, had a glance at the 13th century cathedral, with finely
carved granite porches. They left Dol by train, arriving at
Rennes in time for dinner.

Friday^ May igth, — The party made an early start in
carriages, accompanied by M. Lebesconte and M. Bezier, who
kindly assisted in the direction. Rennes lies in the middle of a
great plain composed of Brioverian shales, portion of a large
anticlinal fold that has been exposed by denudation. This plain
is covered in many places by horizontal patches of Tertiary beds
and Post Pliocene brick-earths. The Brioverian shales were seen
in some open trenches in the village of Bruz. At Rocher the upper
limits of the Brioverian shales are characterised by green flaggy
schists. Their junction with the basal conglomerate of the

KXCCRSIOX TO BRITTANY. 233

Cambrian was seen at La Perriere, where the caniages were
left.

We now come to a new Sikman syndine poualld to diat of
St Aobin d'Aabignd, though it is less deep, as we do not find
higher beds than Upper dorian in the centre, no traces of the
I>evonian or Carbofuferous fonnations having been preserved.
This bann, however, gains in width what it k»es in depth, as it
is not shut in by imbrkated fonlts, in a narrow troogh like the
basin of St. Aubin, but extends with gentle undukoions over
several miles. (See Fig. 4, p. 108.)

The Cambrian rests on the Brioverian at Pont Rdan, and its
crharacter is well seen in the fine quarries by the side of the
^Vilaine. At its base is a siliceous conglomerate containing very
Large pebbles (Pondingoe de Montfort), above which are green
slates and quartzites, with purple flag-like slates in the u{^r
part, remarkable for their fidse bedding. They attain consider-
able thickness, as much as 6,000 feet according to M. Lebes-
^^onte, and make very poor kmd. There are no fossils, except
IL racks of doubtful or^n, known under the names of BUointes^
M^exiUum^ etc At the top is a bed of green slates with Fucoides
^'ouaulH^ Leb. Along the sides of the valley of the Vilaine the
^A^rmorican sandstone is worked in large quarries. It rests on the
d^mbrian purple slates, and is the oldest formation in Brittany in
^^vhich fossils have been identified. The fauna, consisting
^principally of Lingulas and lamellibranchs, indicates a not very
^eep water origin, resembling that of the Arenig formation.
Xt belongs to the lower part of the Ordovician. The principal
0>ssils besides ScoUthus and Bilobites^ are Ogygia, Myocaris^
Cyrtodontay Ctenodanta^ Redonia^ AcHnodanta^ Dinobolus^ and

The Armorican sandstone, which is some 3,000 feet in thick-
ness, is of great importance in the physical geography of this part
of the country, and has largely impressed itself on the landscape
of Brittany. It forms the lines of highest deviation of the
country, consisting of flat-topped and monotonous plateaus,
^^hich are barren except for fir trees. It also forms the chief
source of water supply, coming as it does between beds of im-
permeable shale, which, in contrast to the Armorican sandstone,
form fertile plains. The geological map shows that the parallel
ridges which form a feature in the landscape are due to repeated
foldings of the sandstone.

The sandstone is followed by the Angers slates, which crop
out with great regularity in the four synclinal basins between this
point and Redon. They are coarse blackish slates with beds of
micaceous greywacke and silicified clay nodules containing
fossils. There are beds of workable slate which are particularly
well developed farther south. For the divisions of this series,
see page 109.

234 EXCURSION TO BRITTANY.

At Traveuzot the party collected plenty of fossils from the
Sion slates, including Synhomalonotus tristani^ S. aragot\ and
Asaphus guettardi^ from an opening made for the accommodation
of the geologists by the Company of the Chemins de Fer de TOuest
After a hurried luncheon the members climbed the hill to Laill^
on the top of the Armorican sandstone, where they found the
carriages waiting. From this point the road traverses the beds
which occupy the middle of this synclinal fold till Polign6 is
reached, which is on an isolated knoll occupying the centre of
the syncline and showing the highest beds of the series. Here
are, in ascending order, white sandstones of the same age as the
sandstones of St. Germain-sur-IUe, viz : Upper Ordovician over-
lain by other sandstones, those of Bourg-des Comptes, with
ampelites of Upper Tarannon age above. (See pp. 112 and 113,
and Fig. 7, p. in.)

To the south of the hill of Polign^, in the direction of
PMchatel Station, the party crossed in reverse order all the beds
seen during the morning. (See Fig. 4, p. 108.) Certain of these
beds are particularly well exposed in this district, especially at
Riadan, whence the upper slaty division of the Angers slates takes
its name, while below in the Chatellier quarry the sandstone
of that name is worked, beneath which the Sion slates are
well exposed. The route was resumed across the Bagaron
uplands, along which the character of the Armorican sandstone
is well shown. The Cambrian in this locality is only repre-
sented by purple slates a few feet in thickness, this being an
example of a phenomenon which is met with over and over again in
Brittany in working out the corresponding beds on the opposite
sides of the synclinal troughs. Under these purple slates the
beginning of a new anticlinal axis of Brioverian shales makes its
appearance, on which Pl^chatel Station is situated, whence the
party took train for Redon.

Saturday^ May 20th. — Redon, a curious, mediaeval-looking
town, is situated at the junction of the canalised river Oust and
Vilaine, in the central part of a Silurian syncline. The beds rise
on both sides, folded up into two broad anticlinal waves, broken
in their centre, where the granitic cores are to be seen.

The members left Redon in carriages, following the Vilaine
Valley, too wide for the existing river, and the old remnant of a
channel in which the Miocene and Oligocene waters flowed.
This is the only locality in Brittany where beds of this age
are found.

At St. Jean-la-Poterie the gradual metamorphism of the whole
Ordovician series was seen on approaching the granitic core of
Allaire. The St. Germain sandstone is not altered, but the
succeeding Angers slates become more massive and crystalline,
merging into chiastolite slates ; the Armorican sandstone follows,
but shows hardly any alteration. The actual contact was not

EXCURSION TO BRITTANY. 235

seen, the party coming shortly afterwards on to porphyritic

granite. St. Jean-la-Poterie lies on a Pliocene outlier, worked for

&e manufacture of a most primitive kind of pottery. The clays,

with few fossils — Nassa prismatica^ N, mutabilis^ Terebraiula

variabilis — are overlain by ferruginous sands and conglomerates.

From St Jean-la-Poterie the drive was across the bleak

granitic plateau of Allaire, which consists entirely of medium

grained granite. Leaving the plateau for St. Jacut, on the

Ordovidan beds to the north, the porphyritic granite is again met

^th. At St. Jacut the metamorphosed Silurian rocks are found

sigain, but here we meet higher beds in the Silurian series, com-

;S>rising limestones, ampelites, and variegated shales.

The ampelites are hardened, charged with mica and altered
^rrystals of chiastolite, replaced by green fuchsite. The
:tfemiginous shales of St. Perreux are loaded with specular iron-
^re and andalusite. The St. Germain sandstone is changed
:snto quartzite, and the Angers slates into hard, compact,
^chiastolite slates. The contact sedimentary beds are often
<^=rossed by pegmatite veins and aplitic granulites, offshoots from
'fthe central massive granite of Allaire. Due attention was given to
^Khe atmospheric disintegration, showing massive granite changed
:^nto loose sand, for a thickness of more than ten feet.

The party left the margin of the granitoid mass at St. Jacut, and,
:^resuming the route along the main axis, drove to Rochefort for
lunch. Rochefort-en-Terre is a small, curious old town, amidst
^^ocky scenery, containing many picturesque old houses of the
^•ifteenth and sixteenth centuries, with a ruined castle, an old
^church, and narrow, crooked and precipitous streets.

After lunch, the members walked north of Rochefort to the Arz
^^alley, through the crags of the Angers slates. These slates are
^^emarkably cross-bedded, apparently vertical although nearly hori-
^^ontal, and are faulted directly against the Brioverian shales. Thus
'^his Rochefort syncline is broken at its edges like the St. Aubin
^yncline, and nearly all the other synclinal folds of the country.

The Brioverian shales, as seen in the roadsides, are unlike
"^rhose observed in the neighbourhood of Rennes, being more
iustrous, and having some alternating gritty beds with porphyritic
'Quartz crystals. These special characters art not local, but are
^^onstant throughout the south-western part of Brittany, where
"^rhey have been distinguished under the name of shales and
-^arkose of Bains. The contact of these beds with the Lanvaux
granite was now gradually approached.^

The party drove back to Redon, over the monotonous Landes
^Df Lanvaux. The scenery becomes more lively and picturesque
^M Redon is approached, the two rivers here winding among the
"Varied Silurian rocks of the central syncline.

* For the relations of the granitic ma&s of Lanvaux to that of AUairr, see pp. X17 to 126^
^^ Figs. 13, 13, and 14.

236 EXCURSION IX) BRITTANY.

May 2isL — No programme having been arranged for Sunday,
the majority left Redon by train in the morning for Auray, in
order to visit the celebrated megalithic monuments of the neigh-
bourhood.

The party left Auray in carriages after luncheon, and were
joined near the great Plouhamel dolmens by M. Le Rouzic,
curator of the Miln museum at Carnac, who kindly acted as guide
through the district. The principal object of interest at Carnac
is the celebrated Mdnec monument. It consists of a vast number
of upright stones, varying from 10 to 15 ft. in height, arranged
in avenues or parallel lines. At one end of these Unes is a
circular "Cromlech." These stones were said to have been
11,000 in number, of which only 1,800 now remain. Endless
conjectures have been made as to the origin and purpose of this
mysterious collection, but at present we have but a poor idea of
the religion and government of the ancient inhabitants.

The whole country is commanded by a tumulus on which
is built a chapel dedicated to St. Michael, visited by the party
on leaving Carnac. The average height of this tumulus is about
30 ft, its base is 350 ft. long by 120 ft broad. It is of the kind
called Galgal^ and is composed of about 100,600 cubic ft. of
rough stones, which have been piled up. It was opened in 1862,
and a sepulchral chamber was found at the west end, containing
a human skeleton with weapons and ornaments. These relics,
as well as many others found in the Druidical monuments of the
neighbourhood, are preserved in the local museum at Carnac, to
which they were given by Mr. Miln, who collected them. This
museum was visited under the direction of M. Le Rouzic,
who was formerly Mr. Miln's assistant It contains also
many Roman relics found by Mr. Miln in a Roman villa at
Bossenno in the neighbourhood.

From Carnac the geologists proceeded to the grand megalithic
monuments of Locmariaquer, crossing the ferry at Trinitd-sur-Mer.
At Locmariaquer the party visited successively the Men-er-H*roeck,
a huge menhir some 70 ft long, which lies on the ground, broken
into three fragments ; the dolmen of Man^-Lud, the Table of the
Merchants, and the tumulus of Man^-er-HVoeck.

Every dolmen was in the first instance covered by a tumulus —
a dolmen being a tomb, as has been proved by the objects found
in making excavations. A simple dolmen would be the grave of a
single person, while a dolmen with galleries and a covered passage
would be the burial-place of a family or perhaps of a dynasty.
The clear traces of burials found under the dolmens have proved
that these tombs belonged to a race who, like the Egyptians,
looked upon their last dwelling-places as abodes for eternity, and
built them to last for ever.

Many objects of jade, chloromelanite, and beads found in the
dolmens mingled with the ashes of the dead, have been thought

SXCURSION TO BRITTANY. 237

to have been of foreign origin, such as Extern Europe and
Southern Asia, and have been considered as showing that com-
mercial relations must have existed with the East, but recent
geological research having shown that most of the substances
(under the general name of pyroxenite) occur in situ in the cliffs
of the Morbihan, this conclusion will seem to geologists some-
what far fetched.

Certain other observations may be made by geologists in
studjring megalithic monuments ; thus it is an invariable rule that
they are found in districts where stone abounds, and that they
are only constructed with stones from the neighbourhood.
Thus the monuments of Locmariaquer are larger than those of
Camac, because the soil of the former consists of gneiss and
^^nite which breaks up naturally into larger monoliths than the
granites of Camac, from which locality gneiss is absent.

Another point is that the examination of certain partly sub-
Y3ierged cromlechs in the gulf of Morbihan (er Lanic) shows that
'^here has been an alteration in the level of the land of this region
^ince their construction.

Monday^ May 22nd, — The party left Auray by an early train,
^nd in the course of their railway journey, made a second
'traverse of the country parallel to that of the Vilaine, only in a
^^ontrary direction, viz., from south to north. The route follows
"the valley of the Blavet, and is very picturesque as far as Pontivy,
lifter which near Louddac it crosses the great plain of Brioverian
shales, previously met with in the neighbourhood of Rennes, and
l^ecomes dull and monotonous.

Soon after crossing the watershed between the Atlantic and
^he Channel, the railway traverses the granitic masses of Quintin
^nd St Brieuc, the detailed study of which was to be the day's
'^rork. After having taken up their quarters at St. Brieuc and had
luncheon, the party started in carriages to inspect the Quintin
^"kiass, first crossing the hornblende-schists and dioritic granite of
^t. Brieuc.

In the valley of the Urne to the south of Tr^gueux, the
brioverian shales are exposed with interstratified beds of
^graphitic chert or phtanites. It was in these chert beds that the
XDirector — in conjunction with M. Cayeux — had found what he
l::>elieved to be remains of the oldest known Radiolarians. The
^:iifierence in behaviour of these alternating cherts and shales
^1^ they approach the granitic mass of Quintin, and the character
^:>f the granulitic gneiss resulting from the alteration of the shales
9.re fully described on pp. 127 and 128. (See Figs. 15 and 16, pp.
^28 and 129.)

A very good exposure of the granulitic gneiss was seen in the

little valley of St Julien, south of P^ran, and a halt was made at

"^be vitrified camp of P^ran, a most interesting object to

Archaeologists. The camp is irregular in shape, some 430 ft. by 350,

November, 1899.] 18

238 EXCURSION TO BRITTANY.

surrounded by a rampart with an outer facing of earth 6 ft. 6 in.
in height. Excavations made in 1866 led to the discovery that
walls of stone had formed part of the construction of the rampart,
composed of blocks of diabase, granite, and quartz, and of
charcoal cemented together by a glassy paste resulting from
fusion, by fire, of siliceous rocks, as has been described by M.
Daubr^e. Among the antiquities found there, were some which
made it seem likely that the Romans made use of this fort
while they were constructing the still existing road in the
neighbourhood.

The party then returned to the carriages and drove to St.
Brieuc, the headquarters for the night.

Tuesday^ May 23rd, — The party started in carriages, and
proceeded direct to Pointe du Roselier. From the top of the cliflfe
in the little bay of Port Martin, a fine view was obtained, extending
from Roselier across the Bay of St. Brieuc. The Brioverian
series is seen in a vertical position, recognisable by the beds
of chert which had been seen the day before in the valley of
the Urne ; but these beds of chert are here interstratified with
basic crystalline schists, alternating with the characteristic shales.
The composition of this basic series, and its relation to the
hornblende-granite of St. Brieuc and the diorite of St. Quay,
are fully described on pp. 128 to 131. (See Fig. 17, p. 130.)

The party left Port Martin and drove on without further delay
so as to reach the Bay of Br^hec at low water. This bay, where
the members had luncheon, exhibits a synclinal structure, belonging
to a more northerly fold than all those hitherto traversed by the
Association ; it is easily distinguished by the composition of the
rocks, by the presence of eruptive masses, and by its tectonic
structure. It is not a narrow, deep synclinal trough, like those in the
south of Brittany, but it is a fold with a flat bottom, consisting
of nearly horizontal beds, of which the edges are faulted and
crushed. The enclosing rocks belong to the Brioverian series, nearly
vertical shales and greywackes, seen on the north and south sides
of the bay, those on the south resting on still older mica and chlorite
schists and gneisses. These Brioverian rocks are overlain in the
bay by beds of Cambrian age, which are entirely separated from
them by faults. First we have the magnificent conglomerates of
Br^hec, which exhibit at the base of the Cambrian, remains of all
the granites and basic eruptive rocks of Brioverian age, as de-
veloped between St. Brieuc and Lannion, as well as the schists,
quartzites, and cherts of the same series. Resting on the
conglomerate are red flagstones and calcareous sandstones,
corresponding to the purple slates seen at Pont R^an on the
Vilaine. In a short distance these beds become horizontal and
are traversed by dykes of orthophyre and porphyrite. They are
overlain at Pointe de la Tour by contemporaneous sheets of
diabase, which occupy in these cliffs the centre of the syncline.

EXCURSION TO BRITTANY. 239

Above these diabase sheets, near Plourivo, fdspathic sand-
stones of Oidovician age can be seen, which fix the age of the
series just described, but they do not crop out in the cliS& of
Br^hec. South of the lavas, the other side of the syndine is
seen, but it is so much crushed and fiiulted as to be almost
reduced to nothing. Thb almost complete disappearance, due
to mechanical pressure, of the south side of the basin is one of
the peculiarities of this section. (See Fig. 5, p. 109.)

The party were rather late in leaving the Bay of Br^hec, and
time did not permit of the whole section between Br^hec and St
Brieuc being examined in detail on the return journey. A halt
was made at Tr^veneuc, and most of the members walked to St
Quay to see the dioritic gneisses and massive diorites of Brioverian
age exposed in the clifi^ The drive was resumed from
Portrieux to Pl^rin in the deep valley of the Gouet, where there
^re excellent exposures of Brioverian mica- and hornblende-schists.
Owing to the late hour attention was merely directed to a curious
bed of conglomerate intercalated in the series. The pebbles are
elongated as though drawn out, and are composed of granite,
^plite, and quartz. Though they have lost the rounded form
Usual in rolled pebbles, they must be considered as clastic
on the ground of their mixture in this bed, of their lenti-
crular shape, of their variety in the several overlying beds, of
tiieir occasional transverse position, and of their mixed
composition. The matrix of the conglomerate consists of quartz,
felspar, and black mica, thus having the composition of a
Telspathic mica schist The contained felspar is not clastic, but
a.uthigenic. It is developed in the same way in the schist and
graphitic cherts which alternate with the same crystalline schists
in the neighbouring cliffs of Roselier. These remarkable con-
glomerates of PMrin remind one of the well-known gneiss with
rolled pebbles at Ober-Mittweida in the Erzgebirge.

In the evening the President (Mr. J. J. H. Teall) tendered a hearty
Vote of thanks to the Director for the able manner in which he had
Conducted the geological portion of the excursion ; and another
Vote to Dr. Barrois and Mr. Stebbing for the local arrangements
which had given general satisfaction.

Wedneuiayj May 24ih, — Bad weather setting in on the last day
of the excursion necessitated a considerable curtailment of the pro-
gramme. The proposed examination of the beds round I^mballe
Was abandoned, and the train was taken direct from St. Brieuc to
Oinard. Here it was pouring with rain, and geology was limited
to an examination of the cliffs on each side of the Ranee, at
Oinard itself, and at the island of Grand-Bey.

The cliffs of Dinard and St. Malo show a uniform character
of gneiss traversed by diabase dykes. These gneisses are altogether
<iifferent from those seen in the south of Brittany, which have

240 EXCURSION TO CENTRAL BRITTANY.

been considered the oldest rocks in the district. We do not find,
as in the gneiss of the South, alternations and regular successions
of beds lithologically distinct, gneiss, mica schists, leptynites, and
amphibolites, but we have a uniform magma with a granitic
structure with constituents in alignment, fibres, ribbons, micaceous
and sillimanitic lenticles of amygdaloidal and polyhedric shape
(granulitic gneiss). These are held to be the result of a granite
(granulite) being intimately injected into shales of Brioverian age,
of which the metamorphosed remains would be represented by the
micaceous tissues. These tissues give the rock an interlaced
character, in which wavy micaceous partings divide the lenticular
sheets of massive granulite from each other. The different
divisions of the granulitic gneisses in the St. Malo sheet of
the map are simply mineralogical. They pass one into the
other, and mark the different degrees of metamorphism of the
same rocks.

At St. Malo the excursion came to an end, and the party
broke up, some returning by the boat to Southampton, some
making their way by Mont St. Michel to Normandy, while others
started for Laval in order to examine the well-known Devonian
beds of the Mayenne Department, under the kind direction of
M. and Madame Oehlert.

EXCURSION TO CENTRAL BRITTANY.
Directors: P. Lebesconte and T. Bezier.

{Report by Frederick Mbeson.)

On Thursday^ May i8ih^ a portion of the party visiting Brittany
set out from Rennes to examine the fossiliferous Carboniferous
and Devonian formations of Central Brittany.

The course taken was by St. Gr^goire, Melesse, St. Gennain-
sur-Ille, St. Aubin d'Aubign^, Andouill<§-Neuville, and Gahard.

The Schistes of Rennes, which are identified with those of
St. Lo (Brioverian), and correspond with our Longmyndian, were
found to be destitute of fossils, and covered by Quaternary gravels,
sands, and alluvium.

At St. Gregoire are some Miocene deposits, consisting of
calcareous sand (Faluns de TAnjou) with rolled calcareous
nodules. Fragments of Cidaris were found.

At St. Germain-sur-Ille are majgnificent quarries of sandstone,
bearing the name of the place, and differing but slightly from the
Gres de May of Normandy. It was pointed out that between
Rennes and St. Germain there is, on account of a large thrust
fault, an absence of the intermediate deposits found elsewhere in
November, 1899.]

EXCURSION TO CENTRAL BRITTANY. 24 1

Brittany. In the quarry occur many intercalations of black
micaceous schist, containing the same fossils as the sandstone,
and the following were found : Diplograptus foliaceus and Orthis
hudieighensis. The graptolitic bed is below that containing Orthis.
On the northern side of the quarry^ the faults had changed the
original order of the beds.

The quarry of Carboniferous Limestone, or marble of
Quenon, near St Aubin d'Aubign^ was next visited. This lime-
stone is on the same horizon as those of Sabl^ l^Sarthe) and Vis^
(Belgium), and the sandstone, schists, and porphyroids of the
series seen at points on the route are analogous to the so-called
Blavi^rite de Chang^ (Mayenne). To the proprietors of the
quarry the members were indebted for specimens of the following
fossils found in the limestone : Spirifera^ Orthis^ Leptana^
Chonetes^ Euomphalus^ Productus semireiiculatus, Fenestella^
PhilHpsia gemmuUfera^ and P, truncatula.

Passing a long-disused lime-kiln which presented the appear-
ance of a tumulus, the party reached a quarry of the Rocher
d'Andouill^-Neuville. This sandstone — designated Gres de
Bourg-des-Comptes — is unfossiliferous, and differs in appear-
ance from that of St. Germain. It contains intercalated bands of
carbonaceous shale, in which were found Monograpius priodon,
Jd, colanus^ and ReHolites geinitzianus.

After lunch at St. Aubin, the course of a stream was followed,
in which were exposures of the schists and greywackes of Fret
^Finistere) and Greywacke of Faou (Finistere), which overlie the
IDevonian sandstone. The fossils found included Leptana^
JSpirifera macraptera^ Orthis^ and fragments of Encrinites.
Higher up, at the side of the road, were found Phacops^ Chonetes
jarcinulata^ and Spirt/era,

The quarry at Gr^nelais in Grbs Superieur d'Andouill^, with
overlying nodular shales, was next visited, and Orihoceras^
Cardiola^ Graptolites, Ostracoda, Bolbozae^ and Primitia were
found. The Calcaires de Rosan, which underlie the sandstone,
are wanting here ; and the sandstone is overlain by schist with
the Wenlock fauna.

The classical ground of La L^zaie was reached, and in a
section on the road between L^zaie and Thebaudais-en-Gahard
was seen the greywacke of Faou, in which were found Spirifera^
Orthis^ Pkurodictyum trokiemaiicum, and fragments of Crinoids.
The next visit was to a quarry of Gres de la Boe or Gahard
sandstone, which is very fossiliferous, Orthis monnieri being one
of the characteristic fossils.

The last section seen was the grand one of Bois-Roux, in the
limestone bearing its name. Amongst the fossils found were
Homalonstus gervilleiy Cryphcuus tnichdini^ Leperditia armoricana^
Bembexia, Euomphalus^ Loxonema^ Murchisonia, Nucula^ Athyris
(Spirigera) undata^ Orthis striatula^ and Rhynchonella fallaciosa.

242

SUPPLEMENTARY EXCURSION TO LAVAL.

The following table gives the order of the beds :

Carboniferous Limestone of Quenon.

Mid. Devonian Schists and Greywackes of Fret.

Lower Devonian Greywacke of raou.

,, „ Limestone of Bois Roux.

„ „ Greywacke of Faou.

„ „ Sandstones of Gahard and La Boe.

. I Nodular Shales of Grcnelais.

( Sandstones of AndouilU.

Sandstone of St. Gcrmain-sur-Ille,

and May (Calvados),

Brioverian Schists of Rennes and St. Lo.

Silurian
Ordovician

SUPPLEMENTARY EXCURSION TO LAVAL.
Thursday, May 25TH, 1899.

{Report by R. S. Hbrries.)

In response to a kind invitation from M. and Madame Oehlert,
a party, numbering eleven, travelled from St. Malo to Laval on
Wednesday, May 24th, in order to see the fossiliferous beds of
that district. After dinner they repaired to the house of M.
Oeblert, and were most hospitably entertained by their kind host
and hostess.

On Thursday, May 25th, the party started in a brake under the
direction of M. Oehlert, being accompanied by Madame Oehlert,
and M. Lebesconte, who had come over from Rennes. The
route taken was in a northerly direction, following the course of
the Mayenne, and at right angles to the strike of the various beds.
The following succession of beds in descending order was thus
passed over :

r Shales.

I Limestones.

Carboniferous

DEVONrAN .

? Silurian

Ordovician

Pre-Cambrian ,
Granite.

( Conglomerates.

{Limestones and shales.
Sandstones with Orthis monnieri.
Folded beds.
I Slates.

) Armoncan sandstone.
Shales and conglomerates.

On reaching the edge of the great granite mass at Montflours
the road to the west was taken as far as Andouill^, where a halt was
made for luncheon. Just south of the village an opening by the
roadside afforded an abundant supply of Ordovician fossils. The
beds were now crossed in reverse order, and the next stopping
place was at the great limestone quarries of St. Gerraain-le-
Fouilloux, which yielded numbers of Lower Devonian fossils.
Two smaller quarries were visited between St. Germain and St.
Jean-sur-Mayenne, where the road of the morning was rejoined.

At both these points the limestone was found to be very rich.
November, 1899.]

EXCURSION TO BUSHEY AND HARROW WEALD. 343

In returning a stop was made at Change to inspect the limestone
quarries of Carboniferous age The party returned to Laval well
satisfied with their day's work, and loaded with specimens. At
dinner at the hotel Mr. Whidbome proposed a vote of thanks to
M. and Madame Oehlert for all their kindness, which was heartily
responded to.

On the following morning a visit was paid to the museum,
and the eirceedingly well arranged local collections were
inspected under the guidance of M. Oehlert, after which the
members walked to the railway station and left for their various
destinations.

EXCURSION TO BUSHEY AND HARROW WEALD.

Saturday, May 27TH, 1899.

Director: Rev. J. F. Blake, M.A.

{Report by The Dikbctor.)

This was a cycling excursion in conjunction with the Hertford-
shire Naturalists' Field Club, under the guidance of Mr. John
Hopkinson.

The members of the two societies met at the chalk pit on the
north side of the raUway at Bushey, where they verified the prox-
imity of the outcrop of the Chalk to the Tertiary beds, to be later
examined. The horizon of the Chalk here is not the highest in the
country, though the highest in this district, as the Tertiary beds
overlap different members of the uppermost Cretaceous formation.
Above the chalk is here seen a mass of yellow sand, and at its base
some large pebble gravel. Elsewhere, above the pebbles came
some brick-earth, and it was thought that the purity both of the
sand and clay indicated that neither had been moved far, but were
the relics of Tertiary strata formerly extending farther northwards
than at present

On the road going south, good exposures were seen in a new
excavation of the same coarse gravel at a much lower level indica-
tive that their deposition took place after the main excavation of
the valley.

At the Bushey Pit, the basal beds of the London Clay with a
band of pebbles was seen, and underneath came the sandy clays
of the Woolwich and Reading series with very slight indications
of fossils, while at the base were ferruginous sands and pebbles
worked for about 8 ft. without approaching the bottom. On one
side of the pit were observed some curious bands of whiter rock
more compact and calcareous than usual, which not being seen
on the opposite side of the pit, were taken to be a local variation
of the Woolwich beds.
November, 1899.]

344 EXCURSION TO RICKMANSWORTH AND HAREFIELD.

Thence the party adjourned to the pit in the same rocks at
Watford Heath, where they inspected the fossils collected there
by the late proprietor, Mr. Stone, then a member of the Associa-
tion, and kin(Uy exhibited by his son. Here also the pebbly
Basement Bed of the London Clay was seen, and it was under-
stood that from it the shark's teeth and oysters exhibited had been
obtained, the members themselves verifying the fossiliferous char-
acter of the bed. Here the underlying sands were much better
developed, and they are very pure and white. They go down fai
beneath the level of the quarry, some 14 ft. it was said, and it was
rendered probable that they do so by the fact that though chalk is
required at the kiln it is found more advantageous to cart it from
Bushey than to seek for it on the ground itself.

After inspecting the quarry the members rode south over the
London Clay by Greame's Dyke to " the City," where they had
tea and then dispersed.

EXCURSION TO RICKMANSWORTH AND
HAREFIELD.

Saturday, June ioth, 1899.

Directors: W. Whitaker, B.A., F.R.S., Pres.G.S., and
John Hopkinson, F.G.S., Assoc. Inst. C.E.

Excursion Secretary: A. C Young, F.C.S.
{Report by J. Hopkinson.)

Some of the finest and most instructive sections of the Upper
Chalk in the neighbourhood of London are to be seen at Hare*
field, where, facing the Grand Junction Canal in the valley of the
Colne, there are three large chalk-pits within a distance of a mile
and a half, permission to visit which had been obtained.

Ascending a hill half a mile south of Rickmansworth, a very
fine view of the valleys of the Colne, Chess, and Gade was
obtained. The hill is capped by a thick bed of gravel, one
advantage of which, Mr. VVhitaker remarked, is that we may call
it what we like and no one can contradict us, for it may be
almost anything. He could only say that it was a pebbly gravel,
as coloured on the Geological Survey Map. He believed that it
was not Post-Glacial, and that it had nothing to do with the exist-
ing river in the valley below. In this valley water-cress beds
might be seen, fed by springs from the Chalk, and sometimes by
borings being made to obtain an increased supply of water.

Less than another half mile to the south is Woodcock Hill
Kiln, and here the mottled plastic clays of the Reading Beds
were seen surmounted by the Basement Bed of the London Clay,
November, 1899.]

EXCURSION TO RICKMANSWORTH AND HAREFIELD. 245

consisting of sandy clay and loam with a layer of flint-pebbles in
the middle. Below the mottled clay are fairly-white and brownish
sands, and resting in hollows in the London Clay is a clayey
gravel The mottled clays were seen to hold up water which
percolates through the sandy bed above it.

A pleasant walk of two miles across the fields brought the
party to Harefield, where tea was partaken of at the " King's
Arms.** Xhe Harefield Brick and Cement Works, just beyond
the southern end of the village, were then visited. There is here
a very fine section of the Chalk, Reading Beds, and London Clay
with its Basement Bed. which has been described by Mr. Whitaker
in the Gtology of London^ vol i, p. 1 96.

The section is now rather clearer than it was when this descrip-
tion was drawn up. The mottled clays of the Reading Series are
fully exposed, and the grey sand and clay appear to have a con-
siderable extent. The only foreign rock seen in the bed of flint-
pebbles (at the bottom) was an iron-sandstone, rather friable.
Mr. Whitaker remarked that this bed was much like the Hert-
fordshire pudding-stone, except that it was not in Hertfordshire
^nd was not a pudding-stone. It was in Middlesex, but close
to the Herts, border, and although the pebbles were not con-
solidated with silica, there was silica present in the form of sand.

Several fossils were obtained in the Basement Bed of the
London Clay. Shells chiefly occur in masses, but not in a good
state of preservation.

Passing the Asbestos Mills, formerly, as marked on the
Ordnance Map, the " Copper Mills," the Harefield Lime Works
nirere visited.* Here there is a section of the Upper Chalk
nearly 100 ft. in height giving a better illustration of the
phenomenon of "pipes" than is to be seen elsewhere within
many miles of Ix>ndon. It was quite clear, Mr. Whitaker said,
that the irregular masses of loose sand and gravel which extend
downwards from the top of the pit had really been let down from
above. No surface-action could have formed them ; the chalk
had evidently been dissolved away by water percolating through
fissures, and the sand and gravel had gradually taken its place.
The chalk was seen to be quite evenly bedded.

Crossing the fields to the Springwell Chalk Pit, it was noticed
that the chalk was very little fissured by pipes, this being
due to a bed of comparatively impervious clay on the top.t
Although this pit has been worked for at least thirty years it is
not marked on the 6 in. Ordnance Map.

After a hearty vote of thanks to the Directors, a short walk
along the towing-path of the canal brought the party to Rickmans-
worth Station, those who returned to London leaving by the
8.10 train.

• See Plate VI, vol. vii, Trans, Herts. Sat. Hist. Soc.
t See Plate VI, voU vii, Trtuis. Herts. Nat. Hist. Soc.

246 EXCURSION TO LICHFIELD AND CANNOCK.

REFERENCES.
Geological Survey Map, Sheet 7.
Ordnance Survey Map, New Series, Sheet 255.

1882. Whitaker, W., and HopkiNSON, J.— »' Excursion to Rickmans-

worth.** Record of Excursions^ pp. 149-152. (See also other references

there.)

1889. . — "The Geology of London,'* vol. i. Mem. Ged, Survey.

1894. Holmes, T. V.—" Excursion to Harefield." Froc, GeoL Assoc., vol. xiii,

pp. 281-283.
1894. HOPKINSON, J.—** Field Meeting at Rickmansworth and Harefield."

Trans. Herts, Nat. Hist. Soc., vol. vii, p. xlv, Plate VI.

EXCURSION TO LICHFIELD AND CANNOCK.

Saturday, June 17TH, 1899.

Directors: Prof. C. Lapworth, LL.D., F.R.S., and Prof.
W. W. Watts, M.A., F.G.S.

ExcursiffH Secretary : A. C. Young, F.C.S.
^Report by The Dikxctors.J

The members reached Lichfield at about twelve, and a few minutes
were spent in the Cathedral, the salient points in the architecture
of which were explained by Mr. Frank Raw. After driving
out from Lichfield the first halt was made below Lysways Hall,
where a dam has been constructed by the South Staffordshire
Waterworks Company, impounding the water of the Billston
Brook and its tributary, the Ben Brook. The features of the
drainage basin were pointed out by Mr. Hill, who accompanied
the party. Re-entering the carriages the party were next driven
across the New Red Marl and Waterstones to the entrance
to Beaudesert Park, near to which occurs the more easterly
branch of the eastern boundary fault of the South Staffordshire
Coalfield, which brings up the Bunter Pebble Beds on the
west to the horizon of the Waterstones on the east (see
section). The members, by kind permission of Mr. Sugden,
walked through the lovely scenery of the Park, founded on
Pebble Beds, to the camp, which gives an extensive prospect
over the northern portion of the South Stafibrdshire Coalfield.
A second branch of the eastern boundary fault of the coalfield
skirts the eastern side of the camp, bringing up the Coal
Measures on the west into contact with the Pebble Beds of the
east (see section). Looking out over Beaudesert Old Park,now con-
verted into a flourishing coalfield. Profs. Lapworth and Watts
pointed out the general structure of this part of the coalfield,
drawing especial attention to the work of Jukes in establishing the
fact that the Thick Coal of the southern part of the coalfield
is split up into several seams, separated by hundreds of feet of
measures in the northern part. Many of these seams are being
worked in the collieries about Beaudesert, Rawnsley, Hednesford,
and Cannock.

November, 1899.]

EXCUKSION TO LICHFIELD AND CANNOCK.

247

•«»
o

r
2

•<

Brewood

R.Penk

Railway
Canal

Watling Street

Shoal Hill
Huntington

Cannock Bog

Hednesford Pool
Hednesford Hill

z
h

Rawnsley Hill

Beaudesert Old Park

Beaudesert Hall

C/l

So*

Longdon Hall

Billsron Brook
Ashmore Brook

• Lichfield

248 EXCURSION TO ALDRINGTON, BRIGHTON, AND ROTTINGDEAN.

The drive next crossed the northern tongue of the coal-
field as far as Scout House Reservoir, and from this point for
some distance, the rismg ground on the north of the road
is occupied by Pebble Beds, exposed in many quarries, while to
the south the brick-clays belonging to the Coal Measures,
lying unconformably below, were being worked in numerous large
excavations (see section). The first branch of the Western
Boundary Fault was crossed north-east of Cannock, and the rest
of the journey to this town was over Pebble Beds.

At Cannock the party was most hospitably entertained at tea
by Mr. C. A. Loxton, LL.B., of Shoal Hill House.

A somewhat hurried drive to Stafford took the party near the
huge excavations in the Pebble Beds of Cannock Chase, the
pumping station of the South Staffordshire Waterworks Compauy,
and past Huntington Colliery, where a sinking through the
Pebble Beds has been successful in finding coal.

REFERENCES.
Geological Index Map, Sheet 8.
Geological Survey Map, Sheet 62 N.W. and 62 N.E.
Ordnance Survey Map, New Series, Sheet 154.

1835. MURCHISON.— /'r^. Geol. Sac., vol. i., p. 408.

1859. Jukes, J. B.— " The South Staflfordshire Coalfield." Afem. Geo/. Survey.

1873. MOLYNEUX, W,—Gfo/. Mag., p. 16.

1878. Perceval, S. G.—GeoL Mag., p. 333.

1878. Jennings, J. H.^Geol. Mag., p. 239.

1878. BONNEY, T. G.—Giol. Mag., p. 428.

1880, . — Geo/. Mag., p. 404..

1883. . — Geo/, Mag., p. 199.

EXCURSION TO ALDRINGTON, BRIGHTON, AND

ROTTINGDEAN.

Saturday, June 24TH, 1899.

Dirkctors : F. Chapman, A.L.S., Henry Edmonds, B.Sc, and

C. Davies Sherborn, F.Z.S.

Excursion Secretary : A. C. Young, F.C.S.
(Report by C. D. Sherborn.)

Mr. Frederick Chapman having kindly consented to explain the
Aldrington section-(see Proceedings, p. 259), a small party left
London by the early morning train, and had the opportunity,
therefore, of comparing the Raised Beach and Elephant Bed
at this end of Brighton with that originally described by Mantell
to the east of Brighton. Meeting the main body in the afternoon,
the Directors led the way to the shore, where Mr. Chapman
explained the Pleistocene section, which at this point is :

Soil, etc.

f Elephant Bed 50 to 60 ft.

Pleistocene-^ Old sea-beach 5 to 8 ft.

Sand 3 to 4 ft.

Chalk

November, 1899.]

EXCURSION TO CUXTON AND BURHAM. 249

The " Elephant Bed " rests on the Chalk, which is more
or less horizontal in the section, and so continues to Rottingdean.
The Chalk belongs, according to Barrois, to the "Assise i
Belemnitelles," whidi, he says, forms part of the "Zone k
Marsopites." The chsuracteristic fossils given in " Terrain cr^tac^
sup^rieur," are, among others : Micraster cor-anguinum^ Ofiaster
{Cardiaster) corculum^ Rhynchanella pUcatiliSy Belemnites merceyi^
Inoctramus lingua^ Terebratulina striata^ crinoids, cidarids,
sponges, etc. Large Ammonites (A, leptophyllus) are very
common in the cliff and on the shore, and a magnificent specimen
from this locality has lately been exhibited in the British Museum
(Natural History) Marsupites also occur, but on the outward
journey the party were unable to find specimens, though some
were secured on the return journey, from the shore, in the position
pointed out by the Directors. The liberality also of the landlord
of the " White Horse," Rottingdean, enabled several members to
secure more or less perfect specimens.

REFERENXES.
Geological Survey Map, Sheets 5 and 9.
Geological Survey Index Map, Sheet 15.
Ordnance Survey Maps, New Series, Sheets 318, 333, 334.

H. B. Woodward. — "Geology of England and Wales," 1887 ; pp. 413, 519

(with full references in the footnotes).
C. Barrois. — ** Recherches sur le terrain crdtacd superieurde I'Angleterre,'*

1876 ; pp. 25 to 27.

EXCURSION TO CUXTON AND BURHAM.

Saturday, July ist, 1899.

Director-. G. E. Dibley, F.G.S.

Excursion Secretary : A. E. Salter, B.Sc , F.G.S.
(Report fy The Dikbctor.)

The members arrived at Cuxton at 11. 15 a.m., and visited a
pit a quarter of a mile south of the station, by permission of
Messrs. Weekes & Trechmann. The Director remarked that on
their journey from town they had passed over the highest zones
of the Chalk in the London area, at Gravesend and Farningham
Road. At Strood, they had seen Upper Chalk of a decidedly
low -zonal character, the predominant fossil being Micraster
coranguinum^ with Echinoconus conicus, and in the two and
a half miles from Strood to Cuxton successively lower zones
formed the outcrop, so that it could be distinctly seen
that the beds have a somewhat north-easterly dip. At Cuxton,
the whole of the Chalk (over 200 ft.) was certainly below the
M, coranguinum zone. Flints occur in the upper half of the
section. The typical fossils are the Holaster planus^ Terebratulina
NovRMBER, 1899.]

250 EXCURSION TO CUXTON AND BURHAM.

gracilis^ RhynchoneUa cuvieri^ and associated with this zone, the
Director pointed out that he always found Pentacrinus. A
diligent search was then made over the flint heaps and members
were rewarded by the finding of the above-mentioned typical
fossils in addition to Micrasters — intermediate in form between
M. corbovis and M, coranguinum — Spondylus spinosus^ and two
foreign pebbles.

The next pit, half a mile southward, belonging to Messrs.
Formby & Co., revealed a section lower in the Chalk, and in
a pit a little to the east still lower beds were seen. The latter pit
was entered by a cutting, in which a fine section of hill-wash
resting on valley gravel occurred among the chalk. On the way to
Hailing Ferry, the Director exhibited two very fine palseolithic
and one neolithic implement from the gravel of the neighbour-
hood, also a fine specimen of Radiolites mortoni, Mant.

On turning out of the village street at Wouldham, the extensive
pits of Messrs. Peters and Co. stood out prominently, the
BeUmnitella plena zone being very conspicuous ; these pits are
situated at a higher level than those just left, showing that here
the Chalk is folded or faulted.

At Blue Bell Hill pit the members beheld a magnificent
exposure of Chalk (in the upper pits 300 ft. in depth) containing
the H, planus^ T, gracilis and R, cuvieri zones, and in the next
pit is seen, in direct succession, the Inoceramus mytiloides band
resting on the B, plena zone, both fossils being found /« jiVw, with
about 170 ft. of Lower Chalk, and this again, followed by a fine
cutting in the Chalk Marl, comprised a section which has no equal
in the London area. In the lower pit, Holaster subglobosus is the
typical fossil, while from the Chalk Marl RhynchoneUa manielUana
and Cephalopods are frequently obtained.

The pits were then entered and a goodly number of fossils
obtained, together with a fine piece of sandstone, wood
and calcite. The members then climbed to the top of the
hill, where a grand view of the valley was obtained, with the
Medway cutting through the Gault (as seen in the Burham
Brickfield), and the Greensand and Wealden beds beyond.
Shortly after, descending the hill towards Aylesford, the
sarsens comprising "Kits Coty," and the so-called "countless
stones " (of the same material) in a field below were inspected,
also an exposure at Aylesford in which the Folkestone Sands
were seen capped by valley gravels.

After tea at the George Hotel, the President, in proposing a
vote of thanks to the Director, referred to the work of Dr. Barrois,
Dr. Rowe, Mr. C. D. Sherbom, and the Director, on the Chalk of
the district. Mr. Sherborn and the Director replied, and a vote
of thanks was passed to the proprietors of the pits which had been
visited.

CYCUNG EXCURSION TO THE CHILTERN HILLS. 25 1

CYCLING EXCURSION TO THE CHILTERN HILLS.

Saturday, July 8th, 1899.

Director: H. J. Osborne White, F.G.S.

Excurtim Secntmry : A. E. Salter, B.Sc, F.G.S.
{Rtpart h The Director.)

The party assembled at West Wycombe Station early in the
afternoon, and proceeded westward along the Oxford Road.
Just beyond the village, the Director commented on the patch of
gravel capping the ridge in the vicinity of the church. The
gravel, situated about 520 ft. above O.D. (or 230 ft. above the
valley-floor at West Wycombe), is no doubt, of fluviatile origin,
and like the low-level valley gravels of the immediate neighbour-
hood, consists essentially of flints in diflerent stages of attrition.
The absence of the durable, and easily recognisable "lydite"
pebbles, characterising the Lower Greensand and Portland Beds
out-cropping to the north-westward of the Chalk escarpment, in
the gravels of the Wye and other breaching transverse
valleys of the western Chilterns, furnishes a strong argument
against the view that the streams occupying these valleys formerly
drained the older rocks exposed in the Thame basin, and were
there beheaded by "subsequent" branches of the Thames
developed along the strike of the weaker strata.

Ascending Dashwood Hill, where the road-cutting exposes
some small pipes filled with brown clay-with-flints, the party
gained the Chalk plateau, across which a wide view of alternating
ridge and valley was obtained to the north-eastward. The even
outline of the ridges appears to be due to the local absence of
the mound-like Tertiary outliers on the gently sloping platform
of Chalk, rather than to any former base-levelling the region may
have undergone. Leaving the Oxford Road a little short of
Stokenchurch, the dip-slope was followed down to Cadmore End
Common ; where a short stoppage was made to examine a pit
showing a few feet of mottled sandy clay, underlain, at one spot,
by a lenticular mass of white angular flints, with a few pebbles of
flint, quartz, and dark chert, in a loamy matrix. This deposit,
which occurs at the northern boundary of the Lane End Eocene
outlier, appears to have formerly filled a small valley, whence it
has been partially removed, and it is evidently the result of local
wash ; the pebbles and mottled loam being derived from the
adjacent Reading Beds and pebbly (" Westleton ") gravel, and the
angular flints from the Chalk plateau.

Near Bolter End, a good section of a flint pebble-bed, closely
resembling the Blackheath Beds to the south and east of London,
but here, apparently, forming part of the Reading Series, was
seen in a field on the south side of the road. The Director
remarked on the scarcity of such masses of pebbles in the
November, 1899.]

252 CYCLING EXCURSION TO THE CHILTERN HILLS.

Lower Eocene beds on the north side of the London Basin, and
on the small horizontal range of the deposit in this outlier. The
section showed a depth of about 7 ft., but, judging by surface
indications, the actual thickness of the bed must be quite three
times as great. Between Bolter End and Lane End an example
of Prestwich's Westleton Shingle, which caps the London Clay
on the main mass of the outlier (above 600 ft. O.D.), was
noticed. Its composition is as follows: Flint pebbles; sub-
angular, and a few angular flints ; small white and pink quartz
pebbles, and some small pieces of dark, compact. Carboniferous
chert. A good specimen of the last-named, with impressions of
small encrinite stems, was found by Mr. Salter. While the flints
may well have been derived from the Chalk and Tertiary rocks of
the region, the immediate sources of the rest of the materials of
this gravel is still a matter of uncertainty.

By the side of the road leading from Lane End down to Moor
Common the party inspected two sections showing about 15 ft. of
light greyish sand, with some thin beds of bluish pipe-clay, iron-
stone, and a layer of flint pebbles near the top, forming the
upper part of the Reading Beds. The London Clay, which
comes on immediately above, has been disturbed by human
agency ; but numerous septaria were to be seen on the spoil
heaps hard by, together with slab-like masses of the bottom bed
of that deposit, crowded with casts of shells.

From a spot on the edge of the Common, the Director drew atten-
tion to the effects of the disturbances and dislocations of the strata
on that side of the Lane End outlier. The London Clay and Reading
Beds they had just seen on the slope behind them ran down into
the bottom of the valley across which they were looking, while
the Chalk occurred at a higher level on the north, west, and
south. The contrast between the hummocky, gorse-covered and
wooded surface of the sands and clays, and the open, smoothly-
swelling slopes of the limestone was, in many places, very sharply
marked. Mr. Whitaker's explanation of this unusual state of
things, viz., that the strata had been here troughed and let down en
masse between two pairs of sub-parallel faults intersecting each
other at nearly right angles, seemed to meet the main require-
ments of the case satisfactorily. The maximum vertical dis-
placement was probably not less than 150 ft. An interesting
result of the disturbances referred to had been the production of
a local north-westerly drainage — the valley excavated along the
faulted mass sloping rapidly in that direction (/>., against the
general inclination of the country), to join the Hambleden valley
at Fingest.

Crossing the Common, the Director led the way on foot
through Moor End Wood to a swallow-hole with precipitous sides,
which receives the drainage of the adjoining slopes. The small
streams flowing off the southern end of the Common have cut

CYCLING EXCURSION TO THE CHILTERN HILLS, 255

deep channels through the Eocene clays and sands into the
Chalk, over which the water runs in a succession of miniature
falls — to vanish in the apertures plainly visible round the sandy
floor of the hollow. The members of the party were not a little
impressed by the realisation of the enormous amount of rock-
waste that had been here carried down into the Chalk.

Ascending the western slope of the valley, by Frieth, the ride
down the dip-slope was resumed, through Parmoor and Rockwell
End, where a small plateau of gravel (450 ft O.D.) composed of
partially worn flints and a few flint pebbles was noticed. In
Heath Wood (350 ft. O.D.) the zone of gravel with Triassic
dibrts bordering the Thames valley was entered; and, a little
further south-east, the characteristic quartzite pebbles were
easily recognisable on the fields about Bockmer (336 ft. O.D.).
Descending the steep slope of the Thames valley to Med-
menham the members observed the clear spring thrown out
at the roadside by the Chalk Rock. Proceeding thence
along the Reading Road the next stoppage was made at the
quarry north of Westfield Farm, showing a fine section of the
Chalk Rock, overlain by about 20 ft. of Chalk with layers of
flint nodules, and passing down into grey, massively-jointed, flint-
less chalk, used for building stone in the neighbourhood. The
junction of the Upper and Middle Chalk is marked by a thin band
of brown, marly clay, containing comminuted flints.

Turning to the left near Mill End, the party crossed the
Thames at Aston Ferry, and, after taking tea at the " Flower
Pot," rode on to the pits above Remenham. The first of these
exhibits about 30 ft. of the lower part of the Upper Chalk, much
piped with gravel from above. The second, at a higher level,
exposes a good section, 10 ft. in depth, of well-stratified gravel,
containing a large proportion of material foreign to the rocks of
the London Basin ; amongst which the red and grey quartzites
from the Bunter Beds are very prominent. Near the base of the
section the gravel becomes coarser, and contains rounded blocks
of red and buff sarsenstone up to a foot in diameter. Here and
there the bedding planes curve downward rather sharply,
indicating the position of pipes in the subjacent Chalk. The
gravel exposed in this pit forms a finely developed river-terrace,
at about 70 ft. above the Thames, occupying a convex spur of
the valley slope. From the bank of the pit the members at once
recognised the resemblance this even terrace, backed by rising
ground to the south, bore to the spreads of low-level alluvium
bordering the modern river : a resemblance rendered more than
usually pronounced by the slight depression separating the small
plateau from the slope beyond, corresponding to the backwater
which, in this district, is so often found skirting the wider
expanses of water-meadows through which the main stream
wanders. The Director observed that the Thames here ran in an

November, 1899.] 19

254 EXCXmSION TO GUILDFORD AND GODALMING.

intrenched meander cut in the floor of an older and wider valley,
whose limits were almost obliterated ; and indicated the follow-
ing localities on the surrounding slopes where relics of older
terraces had been preserved, viz., near States Farm, above
Medmenham, 150 ft. ; No Man's Hill and White Hill, respectively
north-east and south-west of Henley, between 200 and 250 ft ;
Bockmer, 250 ft, ; and near Fawley, 350 ft. above river-level.

After an animated discussion on the significance of the form
of, and direction pursued by, the Thames valley in this locality, a
cordial vote of thanks, proposed by Mr. Hopkinson, was awarded
the Director, and the party dispersed.

REFERENCES.
Geological Survey Map, Sheet 7, Drift.
Ordnance Survey Map, New Series, Sheets 254 and 255.

1872. Whitaker, W.— ** The Geology of the London Basin," Part I.
1889. .— ** The Geology of London,'* vol. i, pp. 72, 183-5,

253. 293» 301. 447.
1890. Prestwich, J.—" On the Relation of the We&tleton Beds, etc**

Quart, Journ, Geol. Soc,^ vol. xlvi, p. 140.
1894. Whitk. H. J. O. — "On the Distributions and Relations of the

Westleton and Glacial Gravels, etc." Proc, Geol, Assoc, ^ vol. xiv,

pp. 23 and 29.
1896. Salter, A. E. — '* Pebbly Gravels from Goring Gap to the Norfolk

Coast." Proc. Geol, Assoc,^ vol. xiv, p. 392.

EXCURSION TO GUILDFORD AND GODALMING.

Saturday, July 15TH, 1899.
Director: A. K. Coomara-Swamy, F.G.S.

Excursion Secretary : A. E. Salter, B.Sc, F.G.S.
iReport by The Director.)

The objects of the excursion were to trace the succession
from I^ndon Clay to Weald Clay, and to see the Peasemarsh
anticline.

The party left Waterloo at 1.5 p.m., and proceeded along the
Godalming Road to St. Catherine's Hill (Folkestone Beds). There
the Director pointed out the geological features of the district,
viz. : the line of escarpment of the North Downs and the
Hog's Back ; the Guildford Gap, through which the party had
just passed; and the Lower Greensand escarpment, the deep
southern slope of which is due to the outcrop of the Bargate
Stone.

Descending the hill, an old quarry in the Bargate Stone
on the road to Littleton, was inspected. Proceeding along the
footpath, a new section at the top of the second field was
November, 1899.J

EXCUKStON TO GtJILDtt>RD AND GODALMIKG. i^S

visited. The section shows the lower part of the Bargate
Stone» and the top of the Sandgate Beds, and is fossiliferous.
The footpath along the top of this field (on the surface of which
remani^ fish teeth may be found) was followed to a quarry
showing Bargate Stone and Sandgate Beds, which has been
described by C. J. A. Meyer on p. ii of his Lower Grtensand of
Godalming.

Passing through Littleton, a halt was made at
Brick-kilns, where the following section was seen,
permission of Mr. F. Mitchell :

Soil and weathered Clay

Ironstone Nodules with Atherfield Fossils

Lit
by

tieton
kind

ft.

in.

Brown Cla<

Blue (Wealden) Clay, seen

The following fossils from the nodules have been kindly
identified by Mr. H. A. Allen : Serpula^ Enallaster fittoni^ Forbes,
Ttrebratula sp., Exogyra sp., Pecten quinquecosiatus, Sow., Pecten
sp., Perna rqyana^ D'Orb., Area raulini^ Leym, Modiola comue-
liana^ D'Orb, Modiola sp., Nucuia sp., Cytherea parva^ Sow.,
Fanopaa pScata, Sow., Thetis sowerbyi^ Rom., Cerithium sp.,
Aporrhais sp.

Proceeding across the axis of the Peasemarsh anticline to
Binscombe, the southern outcrop of the Bargate Stone was
ascended, and the Frith Hill section in the Hindhead Road
examined The Director exhibited some of the remani^ fish
teeth which are found in the pebble beds in this section. They
include Lepidotus, Pycnodusy Gyrodus, Strophodus^ Lamna^
AcroduSj Hybodus^ and Sauricthys ? The beautiful preservation
of some of the Hybodont teeth, with their points scarcely at all
worn, is noteworthy. The Director had found similar rolled fish
teeth in the ferruginous sands near Aiherfield, I.W. The upper
part of this section shows Bargate Stone and pebble beds
interstratified. In the lower part the Bargate Stone dies out,
lower still the pebbles become less frequent, and the somewhat
clayey sands of the Sandgate beds are seen. After finding
a few fish teeth, the members proceeded to the Angel Hotel,
Godalming.

After tea, Mr. Herries proposed a vote of thanks to the
Director, who replied, and the members returned to London
by the 7.35 train.

REFERENXES.
Geological Surrey Map, Sheet 8.
OrdoAnce Survey Map, New Series, Sheet 25.

1868. Meyir,C.J. a. — " The Lower Greensand of Godalming," GeoL Assoc,
1898. LeighTON, T.— " Excursion to Godalming," Proc, GeoL Assoc,^
▼ol. XT, p. 445.

2S6 EXCURSION TO CLAYGATE, CHKSSINGTON, AND OXSHOTT.

EXCURSION TO CLAYGATE, CHESSINGTON, AND
OXSHOTT.

Saturday, July 2 2nd, 1899.

Director : W. P. D. Stebbing, F.G.S.

Excursion Secntary : A, E. Salter, B.Sc., F.G.S.
{Report by The Director.)

At Mr. Sims's brickfield, Claygate, a very good section of the
upper part of the London Clay merging upward into the Lower
Bagshot sands was seen, and, at the base, typical London Clay
with septaria, in some cases full of shells. The hard ferruginous
layer, forming an iron pan, Mr. Herries considered to be the
junction between the London Clay and the Lower Bagshot sands.
The clay, greyish in colour at the bottom, becomes browner
towards the top, and is very finely laminated. The proportion of
sand increases towards the junction, so that the highest beds are
too sandy for brickmaking. The section showing the Lower
Bagshot consists of buff and yellow sands with a few partings
of clay.

After Professor Blake had thanked Mr. Sims for his kindness,
the party returned to Claygate. Thence they proceeded south
eastwards to Mr. Welsh's brickfield, where the beds are very much
folded and contorted. The Director thought the foldings and
contortions might be due to landslips, but Mr. Herries suggested
that they might be due to lateral pressure. This section, although
in the same ridge as the former, showed stiff laminated clay without
any sand, and no septaria.

The party next proceeded south eastward to Mr. Sayers's
brickfield on the Surbiton and Leatherhead road. On the way, at
the top of the ridge (241 ft. O.D.) capped with Bagshot Beds, the
clay-bed of a small dried-up pond was seen ; the sides showed
flint pebbles and Lower Greensand chert, furnishing conclusive
evidence, Mr. Herries said, of Prestwich's Southern Drift

The shallow excavation in London Clay in Mr. Sayers's brick-
field is interesting on account of the large size of the septaria
which occur in a bed dipping N.W. A piece of wood bored by
Teredo was found. From this spot the party took the path direct
to Oxshott Station. About half way along the road a well-sinking
had been commenced, and the spoil heap showed dark blue
London Clay with selenite and shells.

After tea Mr. Herries tendered a vote of thanks to the Director
for a very pleasant afternoon, and the members left by the 7.37
train for London.

November, 1899.]

EXCURSION TO CHARLTON, ERITH, AND CRAYFORD. 257

EXCURSION TO CHARLTON, ERITH,
AND CRAYFORD,

Saturday, September qth, 1899.

Director W. Whitaker, B.A., F.R.S., Pres. G.S.

Excurtiom Sicrttmry : A. E. Salter, B.Sc.

A LARGE party met at Charing Cross Station and, accompanied
by members of the Soci^te Beige de Geologie, journeyed to
Charlton by the 10.2 train in order to examine the Rne exposures
of Thanet Sand and Chalk* in the neighbourhood. At 12.56 the
excursion was continued to Erith and Crayford, where the numer-
ous sections of Chalk, Thanet Sand and Drift were inspected.
The last afibrded a large series of mollusca and some fragments of
bone, including the neural spine of a vertebra of EUphas found
by one of the visitors.

After lunch the President offered a cordial welcome to the
Belgian geologists. M. Mourlon, President of the Belgian
Society, replied in French, thanking the Geologists' Association
for the instructive excursion so ably directed by Mr. Whitaker.
Dr. Kemna, in most genial terms, gave a free translation of
this reply.

VISIT TO THE BRITISH MUSEUM, JERMYN STREET
MUSEUM, AND NATURAL HISTORY MUSEUM.

Monday, September iith, 1899.

Excursion Secrttary : Fiu: der ic k M eeson.

At id a.m. a visit was paid to the British Museum, where the
party, including members of the Soci^te Beige de Geologie, were
kindly conducted through the Prehistonc, Ethnographical, Ameri-
can, and Egyptian galleries by Mr. C. H. Read.

The Museum of Practical Geoixkjy was next visited, where
the geologists were received by the Director of the museum (Sir
A. Geikie) and the Curator. Sir Archibald Geikie here undertook
the direction of the excursion, and drew attention to the more
interesting exhibits in the Hall, on the Princi()al Floor, and in the
Palasontological and Rock galleries.*

On the motion of M. Mourlon, a hearty vote of thanks was
accorded to the Director, who replied in felicitous terms.

The geologists then made. their way to the British Museum
(Natural Hlstory), where Dr. Henry Woodward and Mr. A.
Smith Woodward kindly conducted the party through the
magnificent Geological Collection.*

* For a description of the sections and museums visited, sec papen mentioned in tb«
references.

November, 1899.]

258

Proceedings.

REFERENCES.

Geol. Survey Map, Sheet i, S.W. (Diift Edition). New Ordnance Map,
Sheet 271.

1864. Prestwich, J. — "Deposits containing the Remains of Extinct

Mammalia and Flint Implements." PhiL Trans.y vol. div, pt. 3,

p. 247.
1880. Spurrell, F. C. J. — *'On the Discovery of the Place where

Palaeolithic Implements were made at Crayford,*' Q. J, Geol, Soc,^

vol. xxxvi, p. 544.
1885. .—"Excursion to Erith and Crayford." Froc,

Geol. Assoc.^ vol. ix, p. 213.
1889. Whitaker, W.— *' Geology of London.'* Mem, Geol, Survey,
1895. Holmes, T. V.—" Excursion to Charlton." Proc, Geol. Assoc.,

vol. xiv, pp. 111-114.
1897. Spurrell, F. C. J.—" Excursion to Erith and Crayford." Proc.

Geol. Assoc.y vol. xv, pp. iio, 113.

1897. Woodward, Dr. H.—*' Visit to the British Museum (Natural History)."

Proc. Geol, Assoc.^ vol. xv, p. 85.

1898. " Visit to the Museum of Practical Geology." vol xv, p. 287.

ORDINARY MEETING.

Friday, July 7th, 1899.

J. J. H. Teali^ M.A., F.R.S., President, in the Chair,

The following were elected members of the Association :
E. Phihp Barber, Alfred James, F.G.S., Miss Hester Pengelly,
Dr. A. W. Rowe, F.G.S.

The following paper was read :

" A Sketch of the Geology of the Lower Carboniferous Rocks of Derby-
shire," by H. H. Arnold-Bemrose, M.A., F.G.S. Illustrated by Lantern
Slides.

359

THE RAISED BEACH AND RUBBLE.DRIFT

AT ALDRINGTON, BETWEEN HOVE AND

PORTSLADE-BY-SEA, SUSSEX. WITH

NOTES ON THE MICROZOA.

By Frederick Chapman, A.L.S., F.R.M.S.

(Rtmd ytine tmd, 1899.)

I.— INTRODUCTION.

THE Raised Beaches of the Sussex Coast have been the
subject of many valuable papers and memoirs, such as
those by Mantell, Murchison, Dixon, Godwin Austen, Prestwich,
Clement Reid, and others. So far, however, these deposits of
the South Coast have never been systematically investigated for
their microzoa*

The minute organisms from the Raised Beaches and Estuarine
Clays of Scotland and Ireland, which are of later date than
similar deposits of the South Coast, have been studied and well
described by G. S. Brady, Crosskey, Robertson, J. Wright, and
others. In the South of England, we have merely a few species
of Ostracoda and Foraminifera recorded from the Raised Beach
and " Head " of Portland Bill and Chesilton ;• and some Foram-
inifera from a Beach Deposit in Goodwood Park, Sussex.f

From the Raised Beach at Portland Bill, Gwyn Jeffreys
determined Miliolina seminuium and a species of Cy there ; % and
to these Prof. Rupert Jones has added Polystamella striatopunc-
tata and a Cythere sp. nov. ?||

From the angular rubble-bed at Portland Bill, Mr. Etheridge
reports " Cypris striatopunctata and C legumen or fasctcuiata,^'^

At Chesilton two species of Ostracoda were found in the
Rubble or "Head," viz., Cypris [Scoitia\ browniana and Candona
Candida, Also Foraminifera (not specined).ir

From the marine sands in a sand-pit at the S.E. corner of
Goodwood Park, Sussex, Prestwich has recorded the occurrence
of the following foraminifera:** Truncatula \Trtincatulind\
lobatuhiy Rosaiina [Ro/a/ia] beccarii, and Nonionina asterigerina
[?], as determined for him by Messrs. Jones and Parker. In the
same bed of sand these additional fossils occurred : Mvtilus eduiisy

• Prestwich, Qmart. /amrm. Geol. Soc. vol. xxxi (1875), pp. 33. 34, 37, and 39.
t idem^ tbid.t vol. xv (iSm), p. 219. J Idem, i6ia., vol. xxxi, p. 33.

!li/dem,»id.,yolr~~ ' '^'~- -'^-'' ' " "

% Idem^ Aid., voL xx:

November, 1899.]

H Idtm^ ihid.t voL xxxi, p. 34. § Itiem, ibid., vol. xxxi, p. 37.

% Idem^ Aid., voL xxxi, p. 39. •• Idem^ op. cit., vol. xv p. 219.

26o FREDERICK CHAPMAN ON THE RAISED BEACH

Cardium edule, Pholas dactyius [?], Purpura lapillus^ Balanus
torcatus^ and Echinocyamus pu stilus.

Having lately had some opportunities for examining a good
section of the Raised Beach exposed in a sand-pit between Hove
and Portslade, I collected material from various levels, to"
investigate with the microscope, and was rewarded by some very
interesting results, which seem to throw additional light on the
history of these particular deposits.

When Mantell described the Raised Beach and Elephant-Bed
in the neighbourhood of Brighton,* the sections exposed along
the coast to the east of that town were much more extensive than
now. Beyond Black Rock there still remains, however, a great
part of the exposure of the Pleistocene deposits so well depicted
by that author.

On the west of Brighton, by way of Hove, Portslade-by-Sea,
and Southwick, the Raised Beach and Rubble-Drift, although
not of so great a thickness as to the east, is also clearly seen in
the various sand-pits and cliff-sections.

The cliff section towards Hove from Brighton, where the
superficial beds sink almost to the level of the present beach, was
described in some detail by Sir Roderick Murchison in 185 i.f
He also records finding Mytilus edulis and Littorina littoralis
(= Z. obtusatd) in the Raised Beach there.

In his classical paper on the Raised Beaches of the South of
England, Sir Joseph Prestwich gave a diagiam section of the
brick-pit near Portslade Railway Station ; % and this agrees gener-
ally with the sections given below (see Figs, i and 4), which I took
from the exposures in the sand-pits on the coast at Copperas§ Gap,
within 36 yards of one another and almost due south of the Rail-
way Station.

In these sections it will be seen that the thickness and general
character of the Rubble-Drift vary considerably within short
distances, owing to the Drift having been deposited in furrows
running nearly due north and south, from the hills to the sea, a
structure which ca^^ he well seen on reference to the i-mch Drift
map of the Geological Survey.

The manner of the deposition of these superficial beds upon
the Chalk is shown in a section given by Prestwich, || from the
coast at Southwick to the Downs north of Portslade.

In the excavation in the sand of the cliff which I saw at Cop-
peras Gap, the Chalk was not exposed, but it cannot be more than
a few feet below the bottom of the pit, for it appears on the
foreshore.

• •• Fossils of ihe South Downs," Pis. IV and V. Also •* Medals of Creation," and ed.
1854, vol. ii, pp. 852-858.

t Quart. Joum. Geol. Soc., vol. vii, p. 367.

J Ouart. Joum. Gtol. Soc.. vol. xlviii (1892), p. 270, Fig. 4.

5 In the finch map 55pelt *' Coppard's."

1: O^. su/ra ci/., PI. VII, Fig. a.

AXD RUBBLE-DRIFT AT ALDRINGTOX.

361

IL— The RAISED BEACH and its MICROSCOPICAL
CONTENTS,

A. Tlubedcf niuteSand.

CommeDdng at the base of the sections exposed, a short
distance to the cast of Copperas Gap (Fig. 2), there is a thickness
of about 12 to 16 ft. of fine whitish sand, with a few scattered
Aims, large and subangular. This bed of sand shows marked
evidence of current-action, which increases towards the top. The
uppermost 10 inches is of a ferruginous colour, and is inclined to
become laminated Throughout the white sand-bed, but more

11 ■ 1 1 ■ n

.•^^^S^i Bnck-canb «nik few nints. (3ft.)

9 Jt '-^

II -;

FSnxT Bvick-cuth ^sh. 6ia.U pAssing iato

CbaSk »oi Arfsiar Flisx Rabble. (15 h.\

Vxf^ of '^ar^e. «eC-roc»ded Funu embedded
u". Bro*- C-ay— Marine SbelX (4 in.)

Fisc ccr:*-.: - :e-.:ce': Sar.<i* »'.th Mc'.Icaca.
0»:racjca ar>i Fv.ruir.;n:;era. \\i i\.\

j'3~- l"^-^-".' . Coocrcricrary San*i4:cr.e. (To Vcticc: of pit )

Fig.

I. — ^Section of the Raise: Beach and Rvbble-
Drift at Copperas Gap.

especially towards the upper part, numerous shells are found dis-
posed in narrow bands. They are chiefly of one species, Littorina
obtusata^ Gmelin. Numerous fragments of Mytilus eduiis^ L., and
a small example of Purpura lafii/us, L., were also found- One
of the subangular flints, measuring 4^ x 3; inches, was
encrusted with the barnacle, Balanus crenatus. Bruguiere.

In parts of this sand-bed concretionary* sandstone occurs
along the plane of bedding, in pieces varying from an inch to
three or four feet in length, and from the thickness of stout
cardboard to about an inch : sometimes tabular, but often
elongated and in grotesque tuberous shapes.* The percentage
of carbonate of lime in a sample of this concretionary sandstone
was found to be as much as 41-3. Where the shell layers are
fotmd the concretionary sandstone is rare or only in thin paper-

• Tabalarand coaa«tjooaiy ^aziditGce al^ -jccTurK ir, the *a.-.-'.--i: a: .re S E. ccraer A
Goodwood Park, aad in the Raiicd beacii at Hope * No^, K. f T . r v^i^y : a: toth cf these
VxaKtirt its origin ciay be doe to :be ume <:i:>rd;tion'« a.> th ;•*« ie«crl;etl aLcve.

February, 1900.] 20

262

FREDERICK CHAPMAN ON THE RAISED BEACH

like seams ; but where the sandstone-layers are best developed no
shells are found. It may therefore be reasonably supposed that
the shell-bands were the source of the CaCOs which forms the
cement around the grains of the sandstone.

When we examine a thin section of this sandstone the grains
are seen to consist mainly of sharply angular quartz, with a few
rounded grains of the same mineral, and angular chips of flint
in less proportion ; some felspar and other mineral fragments, as

_^^^fl§

' '^^^^^^^^l

h .„

'-A

.^B

Fig. 2. — The Raised Beach and Rubble-Drift at Aldrington,
NEAR Brighton.

A. Rubble-Drift. B. Raised Beach.

a. Shingle Bed. fi. Ferruginous Sand.

c. White Marine Sand with Concretions.

well as glauconite casts of foraminifera, and broken sponge-
spicules, the two last being derived from the adjacent Chalk.
The whole of the grains thus cemented together are separated
from one another by an even area of calcite (see Fig. 3).
It may be assumed that in its early stage this deposit of CaCOj
around the grains was in the form of aragonite, and that this, the
unstable form of carbonate of lime, has since passed into the fixed
form of calcite. From this and many similar occurrences, such as
the oolitic limestones with a crystalline groundmass, it is natural to
suppose that the granules, although lying at first in contiguity with

AKD RUSBLE-DRIFT AT ALDRIXGTON.

263

one another, in the loose condition of sand, have been aft^^rards
spaced oat, as it were, by the insinuation of the concreting
substance. Dr. C- G. CuUis, F.G.S., has also fonned the same
opinion regarding similar structures in the purely calcareous rocks
forming the atoU of Funafuti.

The samples of sand taken for microscopical examination were
obtained from the upper part of the bed, amongst the shell-layers
with LittarituL,

The assemblage of Ostracoda found here is remarkable for its
mixed character. It comprises, besides some recent species of
marine Ostracoda which naturally live near the shore-line, two
species derived from the Wealden, seven species from the Chalk,
and one from the Tertiary
beds. In additioo to these
there are numeious well-pre-
served forms of recent Ostra-
coda which inhabit streams
and pools at the present day;
and which most have been
transported to where they
are now found, in the
gentlest matmer, seeing
that, although so fragfle,
they are in many cases un-
injured.

The OSTRACODA
which I have found in the
thick bed of sand of the Fig. 3--Th:n Section of Concre-

Raised Beach near Portslade ^r--?be!ch^'""^" ^"**" "'
are as follows :

Species found inhabiting Streams, Ponds, and Marshes :

1. Cyclocypris ktvis (Miiller) ; rare.

2. „ Serena (Koch) ; i specimen.

3. Erpttocypfis reptans (Baird) ; i specimen.

4. Prianocypris serrata (Norman) ; fine specimens, fairly
commorL

5. Ifyocypris gibba (Ramdohr) ; frequent.

6. „ bradyi, G. O. Sars ; rare.

7. Candona Candida (Miiller) ; rare.

8. Limnicythere inopinata (Baird; : i specimen.

Marine Species indigenous to the Raised Beach. (Those
marked N. are of northern habit.)

1. Cythere viiiosa (G O. Sars) ; frequent.

2. „ iut€a^ Miiller ; very common.

3. „ conanna, Jones ; rare. N.

4. „ angulata, G. O. Sars : rare. N.

264 FREDERICK CHAPMAN ON THE RAISED BEACH

5. Cythere finmarchica (G. O. Sars) ; i specimen.

6. ., latissima (Norman) ; rare.

Species derived from the Wealden :

1. Cypridea tuberaiiata {Soyf.) \ i specimen.

2. „ valdensis (Fitton).

Species derived from the Chalk :

1 . Bythocypris silicula (Jones) ; i specimen.

2. Bairdia subdeltoidea (Munster) ; i specimen.

3. Cythereis ornatissima (Reuss), var. nuda^ J. and H. ; i
specimen.

4. Cytheropteron concentricum (Reuss) ; 1 specimen.

5. Cytherella obovata^ Jones and Hinde ; rare.

6. „ mu^ns/eri (Romer) ; i specimen.

7. „ avata (Romer) ; i specimen.

Species derived from Tertiary Beds
[? Woolwich and Reading Series] :
I. Cytheridea muelleri (Munster) ; i good specimen.

The FORAMINIFERA found in the sands of the Raised
Beach are also of a mixed character, being both derived and
indigenous. The derived species are all more or less well-known
Chalk and Gault forms, and the indigenous species are similar
to those found on fine sandy shallow bottoms around our coast
at the present day.

The Species of FORAMINIFERA presumably contem-
poraneous with the Raised Beach are as follows :

1. Gaudryina pupoides, d!Oxh. ', rare.

2. Truncatulina lobatula (W. and J.) ; rare.

3. Fuivinuiina exiguGy Brdidy-y i specimen.

4. Rotaiia beccarii (L.) ; frequent.

5. Nonionina astertzans (F. and M.) ; i specimen.

6. „ boueana^ d'Orb. ; i specimen.

7. Folystomella striatopunctata (F. and M.) ; very abundant.

8. „ macella (F. and M.) ; frequent.

The dtx'wt^ FORAMINIFERA, apparently from the Chalk
and Gault, are as follows :

1. Haplophragmium nonioninoides, Reuss; i specimen.

2. ,, agglutinans (d^Oxh.)\ i specimen.

3. Ammodiscus incertus (d'Orb.) ; i specimen.

4. Gaudryina dispansa, Chapman ; i specimen.

5. Buliffiina affinis, d'Orb. ; i specimen.

6. „ variabilis, d'Orb. ; rare, large specimens.

7. „ brevis, d*Orb. ; rare.

8. Bolivina strigillata, Chapman ; rare.

9. Fkurostomella obtusa, Berthelin ; i specimen.

10. Frondicularia archiaciana, d'Orb. ; a fragment

11. Flabellina rugosa, d'Orb. ; i specimen.

12. Cristellaria scitula, Berthelin; i specimen.

AND RUBBLE-DRIFT AT ALDRINGTON. 265

13. CrisU/laria at/frata (Montf.) ; rare.

14- Globigerina marginata (Reuss) ; frequent.

15. Truncaiuiina unf^eriana (d'Oih.) ', frequent.

16. „ refuigens (yLon\{,) \ rare.

17. Afwma/inaammonoides (Reuss); common.

18. Pulvinulina elegans (d'Orb.) ; i specimen.
19- „ haidingerii {d^Orh,) \ rzxe.

20. „ nucheliniana (d'Orb.) ; common,

21. Rot alia exsculpta, Reuss ; common.

22. „ so/danii, d*Orb. ; i specimen.

The presence of the derived Chalk Ostracoda and Foraminifera
is easily accounted for, since they are obviously the result of the
disintegration of the Chalk beds which constituted the cliffs at the
time of the formation of the Raised Beach. The freshwater species
of Ostracoda were in all probability carried down by the streams
which drained the more or less flat surfaces near the coast, and it is
worth the consideration whether these remains of freshwater Ostra-
coda do not point to the former existence of outliers of Lower
Tertiary beds, which, being imper>'ious, would furnish the requisite
conditions of a wet and marshy subsoil. That such a superficial
bed did formerly exist here about the period of the formation of
the Raised Beach is highly probable from corresponding evidence
elsewhere along the South Coast, and especially so with regard to
the overlying Rubble Drift. Should this not have been the case
it would be difficult to understand the presence of marsh-loving
species, which occur in such frequency, where, at the present
time, there is little impervious material resting on the Chalk.*

Another somewhat difficult problem meets us in the presence
of two species of Wealden Ostracoda in the Raised Beach deposit.
The nearest outcrop of the Wealden beds at the present time is
in Pevensey Bay ; but it is more probable that the minute cara-
paces mentioned may have been brought down by a river draining
the Weald, such as the river Adur, debouching at Kingston-by-
Sea,t or the river Ouse at Newhaven.

The Tertiary species of Cytheridea was most likely derived
from an outlier of the Lower Tertiaries.

It is interesting to note in relation to the derivation of the
introduced species of the Raised Beach, that Prof. Prestwich
refers t in a similar way to the presence of fragments of the
fossiliferous Middle- Purbeck rocks in the Head or Rubble-Drift
of Portland Bill. These rocks are not now found in situ on the
Island. Similarly, these fragile fossils are here preserved as
remnants of pre-existent strata.

* A sunilar ca:»e k that of the occurrence of lantl aii<l niar<ili >hellN with Osirac«3da such
x<. Scottia hroxtmimHa and Ctuuhna Candida in ib« Rubble ai Che>iIt<Hi. about which Prof.
Prestwich has remarked "There may have been a piece of marshy ground or a pond in the
Kimeridge Clay here, previously." Quart. Journ. Geol Sac., vol. xlviii (1893), p. 378.

t The River Adur within recent knowledge flowed out at a point nearly opposite
Portibde-by-Sea.

X Qmmrt./emrm. G€0l. Sac., vol. xxxi (1875), P* 3^

266 FREDERICK CHAPMAN ON THE RAISED BEACH

The area in which this sand-bed of the Raised Beach was laid
down may have been slowly subsiding and filling up, since the
condition of the deposit remains the same throughout, and the
shells are littoral species.

B. Topmost bed of Raised Beach, with Shingle layer.

The uppermost four inches or so of the Raised Beach between
Hove and Portslade differs much in character from the under-
lying stratum, and will here be considered separately. It consists
of a layer of large, well-rounded flint pebbles, often measuring
three or four inches in their longest diameter, embedded in
a rich brown sandy clay. One notices, when picking these
pebbles out of the clay, that they are resting directly on a shell-
bed, and fragments of the shells adhere to the under surfaces of
the pebbles. The greater rart of the shells forming this layer are
Mytilus edulis\ and Cardium edule is occasionally found with
them.* The shells of Mytilus found here are extremely fragile,
and it is next to an impossibility to extract them entire. The
reason of this is owing to the partial dissolution of the shell. In
Mytilus the shell consists of an inner layer of aragonite which
readily dissolves, and an outer layer of the more stable calcite.
In the present case only the outer shell-layer remains; and since
this is of a granular texture, the shell is extremely friable. A
similar case was pointed out by Dr. Sorby in his most perspicuous
address to the Geological Society in i879,t when he described a
like condition of the shell of Mytilus in the Raised Beach at Hope's
Nose, Torquay. J

The brown clay, when washed, yields a residuum of dark-brown
sand containing a large proportion of the heavier minerals ; and
amongst these I have detected four which are often found in fine
arenaceous clays. They are zircon, very abundant, some sharply
crystalline, others with the edges of the crystal rounded, and with
numerous inclusions ; also tourmaline, rutile, and kyanite.

The washings from the brown clay also contained, in the
lighter portion, many species of Foraminifera and one Ostracod.
No derived forms were found in this layer, although they are so
common in the beds immediately below and above. This clearly
shows that during this stage of deposition there was an entire
cessation of the fluviatile influences which previously brought
down Cretaceous microzoa and living freshwater Ostracoda from
the land behind. The Foraminifera are all very minute, with
the exception of Polystomella striatopunctata. The solitary valve
of the Cythere found here is very thin and partially dissolved, so
that the superficial puncta are marked by distinct perforations.

* I am indebted to the Misses Constable, of Portslade, for much help in obudning
mollusca from the Raised Beach.

t Quart. /ourn. Gtol. Soc.^ voK xxxv (1879), P- ^S*

t Mr. A. Bell, who has examined the mollusca for me, writes that " this fragile 00a-
dition of the Mytilus shell is not common, and I have only previously met wiUi it at
Shoreham and a few other localities."

AND RUBBLErDRIFT AT ALDRINGTON. 267

Contempoianeous OSTRACOD from the Brown Clay, tap of
Raised Beach.

Cythere lutea^ MuUer.

Contemporaneous FORAAflNIFERA from the same bed.

1. Buiimtna eUgantissima^ d'Orb. ; i specimen.

2. Bolivina punctata^ d'Orb. ; i specimen.

3. „ diiatata, Reuss ; i specimen.

4. „ plicata^ Reuss ; common.

5. „ ttxtilarioidesy Reuss ; freciuont.

6. Uvigerina angtilosa, Williamson ; i specimen.

7. Pate/iina corrugata, Will. ; 1 specimen

8. Discorbina giobuiaris (d.'Orb.) ; i specimen.
9 ,, rugosa (d*Orb.) ; i specimen.

10. Truncatulina ungtriafia (d'Orb.) ; rare.

11. „ lobatula (W. and J.) ; rare.

12. Pulvinuiina repanda (F. and M), var. concamerata
(Montagu) ; rare.

13. Rotalia beccarii {^Axm€) \ i specimen.

14. Nonionina boueana, d'Orb. ; common.

15. Polystomella striatopunctata (K. and M.) ; very common.

From the evidence of the included shells, this bed indicates
slightly deeper water conditions than the bed of sand previously
described, and was probably deposited at such a depth as to be
always below the lowest tide. The rolled pebbles may have been
moved to their present resting-place on the mussel bed by a
sudden change in the set of the currents.

III.— The head or RUBBLE-DRIFT.

The thickness of the Head at Portslade and Hove, and indeed
wherever met with, is extremely variable. Within a few yards,
as will be seen by comparing Figs, i and 4, there is a dif-
ference of 6 ft At Portslade it is almost uniformly composed
of angular flints embedded in a loose, chalky matrix. For com-
parison, we may notice that the Elephant- bed to the east of
Brighton, which is a local development of the Rubble- Drift,
contains less flinty material in the upjKjr part, and in some places
appears as a loose, chalky sand of a whitish or yellowish-brown
colour ; it is largely composed of small chalk pebbles of every
gradation in size, from minute grains up to [>ebbles many inches
in diameter. At Copperas Ga|), between Hove and Portslade,
one of the cliff-sections shows a variation in the nature of the
Rubble- Drift, where a lenticular seam of flne, chalky material
occurs, strongly flexed or even contorted, such as would lead one
to ascribe its origin to ice- or frost-action. The material of which
it is composed, consists of a nearly pure foraminiferal sand,
derived from the Chalk, and is comparable in many respects with

268

FREDERICK CHAPMAN ON THE RAISED BEACH

the Elephant-bed at Black Rock. This seam is very different
from the enclosing drift, which is a coarse rubble of angular flint
and chalk. When a portion of this finer rock was dropped into
a vessel of water, it immediately crumbled down into a fine powder
with a few chalk pebbles and a little suspended material. The
fine sandy residue consisting of Chalk foraminifera is in such
a clean condition as would be almost impossible to obtain by
mechanical means when treating ordinary fresh chalk for the
purpose of extracting the shells. To account for this perfect
disintegration of the rock, it can hardly be ascribed to any other
agency than that of an alternation of frost and thaw. The " chalk
detritus " of Charing, in Kent, which is found at the foot of the

Brick-earth. (3 ft.)

Angular Rubble.

Lenticular patch of fine Chalk Rubble. J. 9 ft.
Angular Rubble.
^^.&^Q^ Rounded Pebbles in Clay. (4 in.)

Fine Marine Sands with Concretionary Sand-
stone formed in situ. (i6 ft.— to bottom
of section).

Fig. 4. — Section near Coppekas Gap.

hills, and which has yielded such a rich harvest of microzoa in
the hands of specialists, may also be due to this particular action
of weathering.

To give a fairly adequate idea of the abundance of microzoa
contained in this chalky seam in the Rubble-Drift, I append the
following lists, the result of a not very exhaustive examination of
the washings. In the sequel, the names of those species are
indicated which were found in a sample of the Elephant-bed of
Black Rock, collected for me by Miss Constable.

OSTRACODA from a lenticular chalky Seam in the Rubble-
Drift near Portslade.

Cretaceous spp.

1. Cythereis spinicaudaia^ Jones and Hinde.

2. „ lonsdaleana^ Jones.

3. „ ornatissima (Reuss), var. stricta^ J. and H.

4. Cytheridea perforata (Romer).

5. Cytheropteron concentricum (Reuss).

6. „ umbonatum (Will.), var. acanthoptera
(Marsson).

AND RUBBLE-DRIFT AT ALDRINGTON. 269

7. Cytherella avata (Romer).

8. „ obovatay Jones and Hinde.

9. „ muensferi (Romer).

10. „ wiliiamsonianay Jones.

A Recent Freshwater or Brackishwater Form.

11. Cyfria Icevis (O. F. Miiller).

FORAMINIFERA from a lenticular chalky Seam in the
Rubble-Drift near Portslade.

1. Textularia giobulosa^ Ehrenberg.

2. „ trochuSy d'Orb.

3. „ conica^ d'Orb.

4. SpiropUcta pralonga (Reuss).

5. Verneuilina spinulosa^ Reuss.

6. Bulimina affinis^ d'Orb.

7. „ pupoidtSy d'Orb.

8. „ murchisonianay d'Orb.

9. „ brevisy d'Orb.

10. „ presliy Reuss.

11. Bolivina decoratUy Jones.

12. Lagena striata (d'Orb.).

13. Nodosaria tenuicostay Reuss.

14. „ obscuray Reuss.

15. Frondicularia angulosay d'Orb.

16. Rhabdogonium tricarinatum (d'Orb.).

17. Marginulina ehngatay d'Orb.

18. Mabellina rugosay d'Orb.

19. Cristeliaria naviculay d'Orb.

20. „ triangularisy d'Orb.

21. „ planiusculay Reuss.

22. „ lituolay Reuss.

23. „ gaudryanay d'Orb.

24. ,, convergenSy Born.

25. „ rotulata (Lam.).

26. „ subalata, Reuss.

27. Ramulina aculeatay Wright.

28. Globigerina marginata (Reuss).

29. Truncatulina lobatula (W. and J.).

30. „ „ var. variabiliSy d'Orb.

31. „ ungeriana (d'Orb.).

32. „ akneriana (d'Orb.).

33. Anomalina rudis (Reuss).

34. „ ammonoides (Reuss).

35. „ complanatay Reuss.

36. Pulvinulina haidingerii (d'Orb.).

37. „ micheliniana (d'Orb.).

38. „ karsttniy ReusF.

2JO RAISED BEACH AND RUBBLE-DRIFT AT ALDRINGTON,

39. Rotalia exsculpta^ Reuss.

40. „ soldanii (d'Orb.), var. nitida^ Reuss.

Derived Chalk FORAMINIFERA from the Elephant-Bed
(Rubble-Drift) at Black Rock, near Brighton.

1. Vemeuilina spinulosa^ Reuss.

2. Bulitnina breviSy d'Orb.

3. Anomalina ammonoides (Reuss).

4. PuivinuUna tnicheliniana (d'Orb.).

5. „ elegans (d'Orb.).

6. Rotalia exsculpta^ Reuss.

Prof. Prestwich, in accounting for the formation of the
" Head," does not admit the agency of ice-action in so recent
a deposit as this, yet, notwithstanding the clear and strong
evidence which that eminent writer has given us in favour of the
theory of submergence, elevation, and disintegration of the
prominent land-surfaces by the strong current-action due to the
emergence of the land, it seems apparent from the evidence given
above, that severe frosts acted, now and again, in a very marked
way, concomitantly with the aqueous denudation.

From the investigations of Mr. Clement Reid * and Mr. Lewis
Abbottt we have no doubt of the existence of shore-ice and
severe frosts at the time of the deposition of the " Mud Deposit "
of Selsey, and of the Raised Beaches, and it is not unreason-
able to suppose that these conditions recurred at intervals during
the formation of at least the earlier part of the Rubble-Drift.

[After completing the foregoing paper on the Aldrington
Raised Beach and Head, my attention was called to a paper
by Mr. S. H. WarrenJ on the same section at Aldrington, which
I had overlooked. Mr. Warren gives the following section, which
generally accords with that given in the present paper :

" 4. Surface Soil I ft.

3. Dark-coloured, stony; clay, descending into pipes 6 in. to 3 ft. or more.
3. Contorted chalky loam, a large proportion of its

mass being composed of flints, often broken, and

said to yield mammalian remains at the base ... lo to 12 ft.

I. Lieht-coloured sand, red in the upper part, with

layers of well-rolled flint-pebbles, and many

concretionary nodules, which are sometimes

tubular. Marine mollusca and Balanidae fairly

abundant. Mytilus edulis in the pebbly layer.

Natica [Littorina obtusata], etc., in the sand.

Seen to 9 ft."

It is also interesting to note that Mr. Warren remarks on the
peculiar contortion of parts of the Rubble-Drift at this spot, and
suggests the probability of grounded ice having been the cause of
the phenomenon.]

• Quart. Joum. Geol. Soc^ vol. xlviii (1893), p. 347 tt teq*
f Op, cit. p. 369, footnote.

X " Note on a section of the Pleistocene Rubble-Drift near Portslade, Sussex.** GfL
Mof., 1897, PP- 302-304.

271

THE PLEISTOCENE DEPOSITS OF THE

ILFORD AND WANSTEAD DISTRICT.

By Martin A. C. Hinton.

{Read /mu a«u/, 1899.)

SINCE 1838, when Prof. Morris wrote a description of the
Ilford beds,* much has been written on the Drift of the
district A review of the literature of the Thames Valley Drift
was published in the Memoirs oj the Geological Survey (" The
Geology of London," vol i, 1889, pp. 353-387).

A series of papers, in part relating to the Thames Valley, was
published in the Geological Magazine during 1872 by Prof. James
Geikict In my opinion his conclusions are incontestable, in so
far as they relate to the Palaeolithic era, and have never been
satisfactorily answered by those holding contrary views.

Another paper to which I shall specially refer is that by Messrs.
Kennard and B. B. Woodward, " On the Post-Pliocene non-
marine,Mollusca of Essex," X ^^ which a complete list of the Ilford
shells is given.

High-Terrace Drift.

Wanstead,

Of this patch, extending from Leytonstone to Wanstead, only
the south-eastern corner lies within our district. In a small
gravel-pit, about a furlong north-west of Wanstead Park, and at a
height^of about 80 ft. O.D., some interesting sections have
been noted.

In the western face of the pit may be seen beds of bleached
pebbles and shingly gravel, probably indications of old land-
surfaces, such as might be formed by the level of the river falling
during dry seasons. In March, 1898, the following section was
exposed on the northern side of this pit :

1. Stratified gravel 1-2 ft.

2. Contorted and lenticular beds of sand 1-2 ft.

3. Gravel, much contorted 4-5 ft.

4. Seams of sand, bluish clay, marl, and gravel,

very much contorted . 1-4 ft.

5. Gravel slightly contorted 2-5 ft.

This section shows that the contorted and disturbed material
is overlain by undisturbed gravel. The overlying gravel is
undoubtedly Pleistocene, and, in my opinion, proves the age
of the disturbance. The contortion was possibly caused by the
grounding and partial melting of a large ice-raft on a shoal in

• Prof. Fohn Morris, "On the Deposits containing Camivoraand other Mammalia in the
Valley of the Thames." Ann. Mac. Nat Hist., Ser. II, vol. ii, 1838, pp. 539*548.
t Afterwards incorporated in " The Great Ice-Age," 1874, pp. 43x-503.
% E$ux Naturaiut, vol. x, 1897, pp. 87-109.

February, 1900.]

272 MARTIN A. C. HINTON ON THE PLEISTOCENE DEPOSITS

the Stream. The fact of its having partly melted, or at least
of the deposition of part of its detritus, is shown by the seams of
marl and of a blue clay, which resembles ordinary boulder clay
both in tenacity and constitution. The ice, thus relieved of its
burden, gradually floated away. This phenomenon would only
occur in a district subject to a severe climate, and the evidence
to be noted below supports this view.

Last October, I found a seam of the dioxide of manganese
in this pit at a depth of about 12 ft.,* and associated with
it was a portion of a skeleton of Equus caballus^ the only fossil
found. Flint implements are rare in this pit, and only a few
small flakes were found, but elsewhere in this patch of Drift they
have been met with in abundance.

Barkingside.

On the left bank of the river Roding are two patches of High-
Terrace Drift. That furthest south shows no section, with the
exception of a few ditch exposures, but its boundary may be
easily traced. The other is much larger, and only the western
portion lies within our district. At St. Swithin's Gravel pit
(90 ft. O.D.) occurs a gravel, overlying sand, similar to that at
Wanstead, but without contortion. "Trail" is often well
developed in this pit. Mr. Crouch mentions that the gravel here
is sometimes slightly faulted, which may be due to slipping.
Loam is seen capping the gravel in the pit and also in a road-
cutting near by. This loam has not been noted by the Geological
Survey. I obtained a considerable number of bones of a small
Bos primigenius or Bison priscus. I have also found several
palaeolithic flint-flakes and implements. Mr. Hatton, the late
proprietor, informed me that teeth of ox and of horse have been
found.

These High-Terrace gravels contain an abundance of large,
smooth, and apparently ice-worn foreign rocks, fragments of
Triassic sandstones, Lickey and other quartzites, and of sarsen-
stones, which have not been subjected to any great amount of
water-action. Among the other foreign materials are large
boulders of Carboniferous chert, of gneiss, and occasionally mica-
schist The presence of these large boulders may be due to the
transporting power of masses of ice, acting upon a river-bank
containing moraine matter. Many of the quartz and flint-pebbles
are also of large size. The smaller material consists chiefly of
flint and quartz with a few Triassic sandstone pebbles.

Dr. Corner possesses a flint implement found in Middle-
Terrace gravel, but evidently derived from High-Terrace Drift,
as shown by its abraded condition, which bears distinct ice-striae
on its fractured surfaces,

• Martin A. C. Hinton, " On Manganese in River Gravels." Scunct Gottip, vol. vi,
S899, New Series, pp. 146, 147.

of thk ilford axd wanstead district. 273

Middle or Low-Terrace Deposits.

Great Ufard.

The deposits of Great Ilford form part of a sheet of Drift
which extnds from the left bank of the river Roding to near
HoTDcfaurdi. Of this great sheet, only the western portion lies
within the district under discussion : but as this portion includes
the Brickearths it is of much interest The principal sections are
situated at a height of 44 ft. O.D , on the northern side of the
railway and on the left-hand side of the footpath which leads to
the iron foot-bridge, in a pit known locally as the " Sam s Green,"
" Cauliflower," or " Page's "* piL The sections exposed are of
great extent and have yielded a large number of fossils, including
the greater part of Dr. Comers collection and the whole of my
own. The sections vary from time to time as the pit is gradually
worked towards the north. In 1897 the following section was
exposed on the northern side :

a. Gravel (Trail) 2 ft.

rib' Dark brown brickearth with shells ]
' I b* Light brown bnckearth with shells > ... 15 ft.

c. Very sandy loam with bones and shells 1

d. Sand 6 ft.

This section was chiefly remarkable on account of the number
of well preserved mammalian remains exhumed. In the winter
of 1897-8, the workmen came upon a portion of a skeleton
of EUphas primigenzus^ with one of the tusks almost complete ;
but the only specimen obtained, was a small upper molar tooth
with the crowns but little worn.

The following section on the northern side of the pit was
noted by me on the 30th May, 1898 :

<r. Gravel and loam (Trail), the pebbles nearly all

having their long axes vertical 2>7 ft.

ft. Brown loam 4-9 ft.

c. Buff loam 5 ft.

«/. Sand, seen to 4 ft.

This section \s remarkable for the great development of the
" Trail'' The underlying bed is much contorted.

The best section is on the western side of the pit. It differs
very little from year to year, and Dr. Corner informs me that in
1898 it was practically the same as in 1893. '^^^ following beds
are seen :

a. Gravel and loam (Trail), very well marked in places 1-4 ft.
Sandy loam, more argillaceous in places ... ... 1-4 ft.

Shell-bed, inconstant, containing numerous shells.

zXso hones oi Bo^ prtmtg^nius gin.-i ft.

Sandy loam 4 ft.

Shell-bed, resting on the eroded surface of Bed c 6in.-i ft.
Buff-coloured loam and marl, with race ; somewhat

sandy (Bone-bed) I-5 ft.

White sand with a few shells 5 ft.

A well sunk in 1 897 passed through sand and gravel 30 ft.

274 MARTIN A. C. HINTON ON THE PLEISTOCENE DEPOSITS

Dr. Cotton* noted a similar development of Drift occur-
ring S.W. of Uphall. That this great development is in-
fluenced by the presence or absence of the underlying gravel is
shown by the fact that between the two places the brickearth
attains a thickness of about 20 ft, and that it rests directly upon
the London Clay.t Hence the Ilford gravel must lie in hollows
or old channels of erosion in the London Clay. Since it is
extremely likely that these hollows would be the first portion
filled up when the deposition of the gravel and sand commenced,
it is probable that the gravel and sand of Ilford form the oldest
part of the Middle or Lower Terrace Drifts of the district.

The large section on the western side of the pit differed
somewhat in 1899. In 1898 and the preceding years, the "Bone-
bed " was observed to overlie the sand. On cutting back the sand
(in 1899), it was seen that the "Bone-bed" became more sandy, and
finally developed into an interstratified series of sand and marl,
dipping to the north at an angle of to deg. Only the lower shell-
bed was to be seen, and towards the south it thinned out altogether.

Fig. I.— Section of Contorted Drift in the Cauliflower
Brickyard, Ilford. x—x. Tusk of an elephant.

The finest examples of Trail that I have noted at Ilford were
exposed in this pit in the spring of 1899. On the western side,
some of the furrows were over 8 ft. in depth, and filled with gravel
and sand. The gravel consists of beds of flint- and quartz-pebbles
(mostly with their long axes vertical) and of thin layers of sub-
angular shingly flint and quartz material, the fragments lying in
all positions. At one point, just below where the " Trail "
commenced to cut down into the loam, a portion of an elephant's

• Dr. R. P. Cotton, " On the Pliocene Deposits of the Valley of the Thames at Ilfoni."
Ann. Ma^. Nat. //i>/.,vol. xx, 1847, pp. 164-9.

t S. V. Wood, Junr., '* On the Structure of the Thames Valley, and of its contained
Deposits." G€0l. Mtm,^ vol. iii, 1866, pp. 57^3, 99-107.

OF THE ILPORD AKD WANSTEAD DISTRICT.

«75

tusk, crashed into small fragments, was seen (Fig. i). On tbe
eastern side, an even finer section of the contorted Drift was
seen (Fig. 2). Thb exhibited several furrows, \-arying from 8 to
9 ft. in depth, and filled with similar debris to that occurring in
the other parts of the pit. The contorted loam was in places
forced up into long thin necks, projecting into the furrows. This^
with the crashed tnsk mentioned above, may be taken as evidence
of the crashii^ action of ice.

Fig. 2. — Section of Contorted Drift in the
Cauuflower Brickyard. Ilford.

I. Gravel and Sand of Trail.

3. CoDtorted loam, torn up into necks at x.

3. Sand (much indurated) false bedded in places.

In March, 1893, Dr. Corner discovered a flint flake or knife
in the lowest shell-bed of the western section of the pit, and this
year he has found another in the same place. So far as
we are aware, these are the first traces of human work known
from the brickearth at Ilford.

The section exposed on the northern side of the pit in 1899
was as follows :

a. Gravel, sand, and clay (Trail) 3-4 ft.

b. Sandy loam, contorted in its upper part 4-6 ft.

c. Brown loam with mammalian bones and teeth,

about 6 ft.

The suncracks that occur in the beds form an interesting
feature occasionally to be seen in this pit. They consist of
vertical fissures filled with sand, which is often cemented into a
hard mass by iron-oxides. They are of two distinct ages,
Pleistocene and Recent, and may be distinguished by the
following characteristics : Those of Recent age are the more
abundant, and invariably reach the surface. Many of them
are formed each summer after the surface soil is removed. The

276 MARTIN A. C. HINTON ON THE PLEISTOCENE DEPOSITS

infilling material, when present, is seldom consolidated. So
numerous are these fissures, that, in the upper portion of the beds,
it is a matter of great rarity to find any of the abundant mammalian
remains unbroken by them. On the other hand the Pleistocene
suncracks may be regarded as those not reaching the surface, and
always filled with material which is more or less consolidated by
oxides of iron, and occasionally by the black di-oxide of manganese.
These Pleistocene suncracks in the beds of loam, are to be
explained by the action of the heat of the sun acting upon mud-
banks when the river was low, causing the mud to contract and
form fissures, which, when the river again rose, became filled
with detritus and were ultimately covered with fresh deposits of
loam or other material.

In August, 1898, 1 noted a section in the old pit on the right-
hand side of the footpath leading to the iron footbridge, which
is one of three described by Prof. Morris in 1838. It has been
abandoned now for several years, but I was able to make out the
following details :

a. Gravel and sand (" Trail ") 3*4 ft.

b. Brown loam, bottom part much obscured ... 4 ft.

b, (?) Pebbly loam 4-6 ft.

c. Thin layers of sand and clay with fragments

of shells 4 ft.

The beds lettered " c " appear to be very constant at Ilford,
sometimes in the form of buff loam, and sometimes as above. In
some places bones are extremely abundant, the layer being termed
the ** Bone-bed" by the workmen. Wherever this bed is argillaceous,
it is also very calcareous and full of large nodules of " race."

Westward of the River Roding,

From Great Ilford towards Manor Park the Drift becomes
thinner, being nowhere more than 20 ft. in thickness, and
generally much less, as the following sections will show :

Excavations for houses in Carlyle Road, Manor Park :

r. Gravel and sand with a Palaeolithic flake ... 6-8 ft.
2 Sand with bones of Equus caballu^ and Bos

ffrimigenius 1 2- 14 ft.

London Clay throwing out water at a depth of 20 ft.

Further east in the same road was seen :

1. Gravel with thin seams of sand 4-5 ft.

2. Sand 10 ft.

London Clay throwing out water at a depth of 15 ft.

At the City of London Cemetery the gravel is in places only
8 or 9 ft. in thickness, and London Clay is to be seen at the
bottom of many of the graves. Flint implements are very
abundant in the gravel.

or THE ILft>RD AND WANSTEAD DISTRICT.

277

LIST OF VERTEBRXTA FROM ILFORD.

Mammalia.

H9mu> (implemencs)

Cmms Im^us, Lino.

Cmmis vnlpe%. Lion.

Fihs Uj, Linn

C'rsms arctM, Linn.

CrsMS fnrox, Richd.

BtsoH SonasMS. Linn. Tar. prtscus, Boj. ...

Bas iamms, Linn. wzr. frtmtgenms, Boj.

Cervus elspkus, Linn. ...

Omti t^tgoMUus, Blum.

Capreolus caprea. Gray ...
Eupkas amtiqums, Falc. ...

Elepkas primsgrmitis. Blum

£far«i ca W/kr. Linn

HippopotamMS ampkibrus^ Linn.

Om ?

Rkrmocgros amtiqmitatis. Biaxn. ...

Rkmoceros Uptorktnus, Owen

Rkmoceros megarkiHus, Chrisi. ...

RODENTIA.

AfKrotui (^Arcicola) ampktiims, Linn. ...
Microtms \.Arxicoi2) arvaJts ?. PaU.
Castor fib^, Linn.

Anas sp. ...

Anser sp

Dumudia exmlvu. Linn.

.AVES.

Pisces.

Esox lucius, Linn....

Uphall ptt Caaliflavcr

X
X
X
X
X
X
X
X
X
X
X
X
X
X
X

X
X
X

X
X

X
X
X
X
X
X
X
X
X
X

X
X

Notes on the Vertebr.\t.a.

Carmivora. — .\mong the camivora found fossil at Ilford,
Canis is the most abundant. Dr. Corner possesses a fine skull
of Canis lupus from the " Trail," which I regard as a genuine
Pleistocene fossil. The remains of Ursus are rare. Rarest of
all is Felis.

Ungul.\t.\. — ^The more abundant species are Bos primigenius
and Bison priscus. It is the general rule to refer bovine bones to
the former species as it is not generally deemed safe to venture to
distinguish between them, except in cases where the skull and
horn-cores are preserved. On this account the abundance of
Bos primigenius may be somewhat exaggerated.

Cervus elaphus is the common form of deer found at Ilford^
February, 1900.] 11

278 MARTIN A. C. HINTON ON THE PLE1STCX:ENE DEPOSITS

but Cervus tnegaceros is extremely rare. Cervus tarandus is
unknown from any Pleistocene deposit in the Thames Valley
below Ix)ndon, although it has been found in the Holocene of
Walthamstow.

Equus caballus is fairly common, and is generally of medium
size. Of the specimen from the High-Terrace Drift of Wanstead,
exhibited at the Conversazione of the Association in 1898, the
rudimentary metacarpal and metatarsal bones were of large size.
Besides these, a case of unequal ossification of the tarsal bones of
both legs was exhibited.

Euphas primigenius is the common form and in addition
a peculiar variety occurs.*

Rhinoceros leptorhinus occurs in great number, R, megarhinus
is fairly abundant, but remains of R. antiouitatis are very rare,
and have not been recorded from the Cauliflower brickyard.

Rodentia. — Castor fiber, A very fine series of bones of C
fiber^ obtained from Uphall, is preserved in the Museum of
Practical Geology (Cotton Collection). Microtus {Arvicola)
amphibius^ the water vole, is also recorded from Uphall, and
specimens are in the Cotton Collection.

These two species were the only small Rodentia known from
Ilford until 1898, when I discovered in the Cauliflower Pit a small
cheek-tooth and portion of a femur. The cheek-tooth Mr.
Newton has identified as the second right upper molar of Microtus
(Arvicola) amphibius — a species already known from Uphall.
The femur, however, supplies us with a new record for Ilford.
Mr. Newton says that, from its size, it is referable to a small field
vole, and corresponds most nearly with Microtus (Arvicola)
arvalis. These specimens indicate a possible source from which
more of these small vertebrates may be obtained.

AvES. — Portion of an ulna of Anas sp. is preserved in the
Museum of Practical Geology (Cotton Coll.) from Ilford, and
there is also a fragment in Dr. Corner's collection. These arc
the only specimens known from the Thames Valley Drift. Anser
sp. is represented by a portion of an ulna, in the Cotton ColL
The specimen is the only one known from Ilford, but the
species occurs at Crayford. A left ulna of Diotnedia exulans^
from Ilford, is preserved in the Museum of Practical Geology.
There is some doubt as to this being a Pleistocene fossil, but
its general appearance is not unlike that of many of the bones
obtained at the Cauliflower pit. I am of opinion that it is a
genuine Pleistocene fossil.

Pisces. — The sole representative of the fishes is Esox lucius^
the pike, preserved in the British Museum (Brady Coll.).

• W. A. Davies, •*On a Variety of EUpkat ^rim'geMiMS from Ilford," "Cat. Pleist.
Vertebrau in the Brady Collection." 1874. P. 4. See also E. T. Newton's " Vertefarata
of the Forest Bed." Mem. Gtcl. Sutv.^ i88a, p. 106.

OF THK ILFORD AND WANSTEAD DISTRICT. 279

It will thus be seen that twenty-six vertebrates occur at
nford, of which twenty-five are known from Uphall and
seventeen from the Cauliflower pit Of these vertebrates, twenty-
two are mammals, three are birds, and one a fish.

Conclusions.

The High-Level Drift of the Ilford and Wanstead district, as
we have seen, gives strong evidence of the rigorous nature of
the climate during the earlier part of the Paleolithic period. At
Wanstead there is unmistakable evidence of the rivers having been
frozen in winter ; and, on the breaking up of the ice, of huge ice-
rafts floating down, contorting the deposits in process of formation
wherever they grounded, and depositing their burdens of detritus.
Similar occurrences were brought to the notice of the Association
by Mr. Allen Brown when dealing with the High Terrace Drift of
Acton and Ealing.* The antiquity of these disturbances admits
of no argument, for in the cases above mentioned they have been
overlain by Pleistocene deposits. Furthermore, they are on a
scale that is never attained by the ordinary surface-derangements,
and more particularly was this the case in the occurrences
noted by Mr. Allen Brown.

In the fauna of the High-Terrace Drifts of the Thames
Vaiky, we find that, among the Mollusca,t there is but one
record of a southern shell occurring in these deposits, viz.,
Carbicula fluminalis from Dartford Brent. It does not follow,
however, that because Corbicula fluminalis has now a southern
range it indicates a warm climate. It must be noted that this
form occurs in the Red and Norwich Crags and in the inter-gladal
beds of Kelsea. The latter beds I take to be equivalent in age
to the earlier Palaeolithic deposits, and as they contain, besides
Carbicula fluminalis^ the marine shells Cyprina islandica and
Tellina balthica^ in all probability it could withstand a cold
climate. The other shells are of a northern facies, or, at least,
could have withstood a cold climate.

Of the Mammalia we find only such forms as the ox, horse,
mammoth, and woolly rhinoceros.

But when we examine the fauna of the Lower-Terrace brick-
earths we find that instead of the scanty species and numbers of
the H^h-Terrace Drift we have evidence of an extremely rich
fauna. The herbivorous Mammalia include the southern forms,
such as hippopotamus, rhinoceros, and elephant, while of the
Camivora, lion and hyaena occur.

With regard to the MoUusca, a similar contrast is exhibited

• J. Allen Brown, " Notes on the High-Level Drift between Hanwell and Ivcr." Prwc
Ctcl. Assoc, t vol. XIV, 1895. P- X53-

t B. B. Woodward, "On the Pleistocene (Non-marine) MoIIusca of the Loodoo
District." Pr»c. Gtol. Assoc. ^ vol. xi, 1890, pp. 3i$-388.

28o MARTIN A. C. HINTON ON THE PLEISTOCENE DEPOSITS

between the present and the Palaeolithic faunas. The Pleistocene
molluscan fauna, as represented in the fossiliferous brick-earths, is
admitted to be richer than that now existing. Though many of
the species range from North Africa to the North of Europe, still,
seeing that they attain their maximum development, as a whole,
in the warm southern regions of Europe to-day, is it not reason-
able to assume that their great Pleistocene development took
place during a period in which the climate was as genial as it is
in these islands at the present time? Numerous specimens of
Littorina rtidis have been found in the brick-earth at Crayford,
and Paiudestrina ventrosa is known from Crayford, Ilford,
and Grays. The examples of Littorina rudis are all dwarfed
and are exactly similar to a form living at Tilbury, while
Faludestrina ventrosa is a well-known brackish-water shell. A
record by Prof. Seeley of Scrobicularia piperata from the Ilford
brickearth * led to an inquiry as to the correctness of its
occurrence. Prof. Seeley very kindly gave me the following infor-
mation in reply. He says :

" Scrobicularia was found, and the determination is given on
my authority from specimens shown me in the pit at Ilford. They
were rather small. I did not take any myself. ... I will see if
any specimens can be traced. My impression is that two or three
entire and one or two broken valves were found. . . . The Ilford
occurrence of Scrobicularia is interesting to anyone who has
studied its distribution and variation on the mudflats of brackish
water inlets on the Coast of Suffolk, where it may be found side
by side with freshwater shells."

In 1872 the Rev. O. Fisher suggested that at the time the
Crayford brickearths were deposited " The Thames could hardly
nave been a tributary of the Rhine, but must have possessed an
estuary of its own as at present, and probably the tide came
even higher up than it does now."t

Mr. VVhitaker, however, did not agree with this view, and
stated that "There is nothing in the fossils to show the
presence of this tidal action."J The presence of these marine
and estuarine forms, however, lends great support to the Rev.
O. Fisher's views.

When we examine the lithological character of the brick-earth
and the gradual passage into it of the gravel below, we are led to
the conclusion that between the deposition of the gravel and that
of the brick-earth, there was a general amelioration of climate.
Can the " Trail " be referred to ice-agency ? In my opinion it
can, and for the following reasons : The contortion of the Drift
when seen on a large scale, can only be ascribed to a heavy
weight ploughing through and over it ; also the position of the
pebbles, which have, as a rule, their long axes in a vertical

* " Handbook of the London Geological Field Class."
t Gtol, Mag,y vol. ix, pp. 263-9.
X •' Geol. of London," vol. i, p. 636.

OF THE ILFORD AND WANSTEAD DISTRICT. 28 1

position, showing that the force was exerted in a vertical and not
in a horizontal direction. The occurrence, noted when discussing
the Ilford section, of an elephant tusk crushed by the " Trail,"
is very weighty, if not conclusive, evidence as to the cause of this
phenomenon.

From this evidence there seems but one conclusion to be
drawn. The earlier part of the period was undoubtedly character-
ised by a severe climate as shown by both the stratigraphical and
the palaeontological evidence. Contrasting, however, the abun-
dance either in numbers or in species, or contrasting the conditions
of life of representatives of the Low-Terrace mammalia now
living, with those exhibited by the representatives of the High-
Terrace deposits, we are forced to the inevitable conclusion that
all these facts tell of a less rigorous climate, and of conditions
that would be impossible, unless we regard these deposits as
belonging to one of the interglacial periods since the forma-
tion of the great Chalky Boulder Clay. That the severe
conditions returned once more is shown by the presence of
the "Trail."

The succession of the Pleistocene deposits of the Lower
Thames Valley may be tabulated as follows :

4. Trail Close of Palaeolithic period. Cold period.

3. Middle Terrace Gravels (in 1 »' t> 1 xuw i- • 1......:^^

part) and Brick-earths I '^««"^='>'=°''""= Oemal period.

2. Middle Terrace Gravels (in

part)

High Terrace Drift

(in)

Eart) V Older Palaeolithic Cold period.
Terrace Drift ... )

My especial thanks are due to the following gentlemen : to
Dr. Frank Corner, M.R.C.S., F.G.S., for the loan of specimens
from his collection ; to Mr. A. S. Kennard and Mr. B. B. Wood-
ward, F.L.S., F.G.S., for their kind determination of the Ilford
mollusca; to Mr. E. T. Newton, F.R.S.,and Mr. H. A. Allen, for
their aid in naming the mammalia, and also to Mr. Pringle, M.A.,
B.Sc, of the Museum of Practical Geology, for his kindness in
connection with this paper.

282

THE PLEISTOCENE NON-MARINE MOLLUSCA
OF ILFORD.

By a. S. Kennard and B. B. Woodward, F.G.S., F.R.M.S.

{Rtad June ^nd^ 1899)

IN 1890 an account of the non-marine rnollusca from this
locality was read before the Association by one of us, and
was published in the Proceedings.* Since then Dr. Frank
Comer, M.R.C.S., F.G.S., has collected extensively at Ilford, and
the results of his labours were given by us in i897.t During the
last four years Mr. M. A. C. H in ton has also worked at these beds,
and he very kindly placed his collection at our service. We now

Eossess a fair knowledge of the mollusca from the Pleistocene
rick-earths of Ilford. In the first place it must be remarked
that the older collections were all made from the Uphall pit,.
whilst the specimens in the cabinets of Messrs. Corner and
Hinton were obtained from the pit variously known as Sam's
Green, Page's or the Cauliflower pit. Since the Uphall examples
are from a slightly lower level, there is perhaps a difference in age,
and it is advisable to list them separately on this account. With
regard to the occurrence of the Uphall specimens Dr. Cotton
remarked, "The two genera of shells of which hundreds may
often be obtained at one visit are Helix and Cyrena, but Unia
and Planorbis are not uncommon, and AncyiuSy Succinea^ Valvata^
Limnaus^ Cyclas^ and Paludina have been discovered. They are
chiefly seen in the layers of sand upon which the brick-earth
reposes, and beneath the bones that are sometimes intermixed
with them, and have been found even within their cavities. They
appear to be partial in their distribution, and are not met
with in the former cutting " [/>., on the North side of London
Road, Curtis* brickfield]. J The examples from Sam's Green pit
are scarce and occur chiefly at one level, but single examples
may be found scattered throughout the mass of brick-earth. In
spite of the former abundance of shells in the Uphall pit hardly
any trouble was taken to collect examples ; but it is quite possible
that many specimens may still exist in old collections. There
are only two series known to the Authors, one in the Natural
History Museum, and the other in the Museum of Practical
Geology. Twenty-two species are represented, viz. :

* B. B. Woodward, " On the Pleistocene (Non-Marine) Mollusca of the London
District,' Proc. GeoL Assoc. ^ vol. xi, pp. 33«;-338.

t A. S. Kennard and B. B. Woodward, '^The Post-Pliocene Non-Marine Mollusca of
Essex," Essex Naturalist ^ vol. x, pp. 87-109.

X R. P. Cotton, *• On the Pliocene Deposits of the Valley of the Thames at Ilford,*"
Ann. and Mag. Nat. Hist, xx (1847), P* i^S-

February, 1900.!

THE PLEISTOCENE NON-lfARIHE MOLLUSCA OF ILFORD. 283

Vitrea nitida (MulL).
Eulota Jrutioim (MulL).
Vallonia fukheUa (MulL).
Hygromia hispida (Linn.).
Hdicella caperaia (Moot.).
He&x nemoralis^ Linn.
Cochlkopa luhrica (MCilL).
Sucdnea fmiris (Linn.).
Umnaa peregar (MulL).
palustns (MulL).
„ truncaiula (MulL).

Planarbis a&us^ Mull.

„ margimaius^ Drap.
HneaiMS (Walk.).
Bythinia tentaculata (Linn.).

„ leachii (Shepp.).
Vahata piscincUis (MulL).
UniopUiorum (Linn.).

„ tumidus^ Retz.
Carticula fluminaHs (Mull.).
Pisidium amnicum (MulL).
„ fontinaU^ Drap.

The following nine species have
examples of them are known :
VUreafulva (MulL).
Pyramidula ruderata (Stud.).
Pupa muscomm (Linn.).
Vertigo antivtrtigo (Drap.).

been recorded, but no

Sucdnea oblonga^ Drap.

Carychium minimum (MulL).

Ancylusfluviatilis^ MulL

Umnaa auricularia (Linn.).
Planarbis comeus (Linn.).
There is no inherent improbability in any of these records,
but it would be more satisfactory if examples were known
of Pyramidula ruderata (Stud.). The record is on the authority
of Dr. J. Gwyn Jefirejrs, who, in 1869, during the discussion
following a paper by Professor W. Boyd Dawkins "On the
Distribution of the British Postglacial Mammals,'"* mentioned
that this species and Eulota fruticum occurred at Ilford.
Examples of the latter are, of course, known, but Mr. W. H.
Dall informs us that there are no examples of P. ruderata in
Dr. Jeffreys' collection, which is now at Washington. It is
extinct in this country, and is only known fossil from three
localities, BamwelL Copford, and Clacton, although, of course, it
is still an abundant form on the Continent, ranging as far north
as Sweden.

Dr. Comer's collection from Sam's Green pit contained
twenty-four species, whilst twenty-seven were represented in
Mr. Hinton's, the combined list showing a total of thirty-
four, viz. :

Vitrea nitida (MulL).

„ nitidula (Drap.).
Vallonia pulchella (MulL).
Hygromia hispida (Linn.).
Helidgona arhustorum (Linn.).
Helix nemoraliSy Linn.
Helicella virgata (Da Costa).

„ caperata (Mont.).

Pupa cylindracea (Da Costa).
muscorum (Linn.).

Vertigo antivertigo (Drap.).
Sucdnea putris (Linn.).

„ elegans^ Risso.
Limncea pereger (MulL).

„ palustris (MulL).

„ truncatula (MulL).

„ stagnalis (Linn.).

„ glabra (MulL).
Planarbis glaber, Jeff.

„ carinatuSy MiilL

• Quart, Joum. Gtol. S»c,^ voL xxv, p. 19a.

284

A. S. KENNARD AND B. B. WOODWARD ON THE

Planorbis marginatus^ Drap.

„ vortex (Linn.).

„ spirorbts (Linn.).

„ contortus (Linn.).
lineatus (Walk.).
Bythinia tentaculata (Linn.).
Valvata piscinalis (MiilL).

Valvata cristata^ Mull.
Corbicula fluminalis (MiilL).
Anodonta cygncea (Linn.).
Spharium corneum (Linn.).
Pisidium amnicum^ Miill.

„ astartoideSy Sandb.

„ pusillum (Gmel.).

Of these no less than sixteen species are unknown from
Uphall, whilst there are seven species from that locality as
yet unrecorded from Sam's Green pit. Two species, Vertigo
antivertigo and Pupa muscorum^ recorded from Uphall, but of
which no specimens can be traced, are now listed from Sam's
Green pit.

Notes on the Species from Sam's Green Pit.

Helicella virgata is represented by a single example, and its
occurrence is of great interest, since it is unknown in any other
deposit, either Pleistocene or Holocene, of the Thames Valley.
It was fairly common in the Pleistocene of Barnwell, and is not
rare in a hill-wash, of Neolithic age, at St. Catherine's Down,
Isle of Wight. Elsewhere it is unknown in any pre- Roman
deposit, though, at the present day, it is one of the most abundant
shells, and is gradually extending its range.

Pupa cylindracea has an even more curious geological history.
It is known from the Norwich Crag at Bramerton, and has been
recorded (but no specimens are known) from Clacton. It was
common at Copford, but the age of that deposit is uncertain. It
also occurs in similar beds at Chignal St. James', Felstead, Rox-
well, and Shalford.

Of particular interest was a Limmeay which differed so
much from all recent British forms that we invoked the aid
of Dr. O. Boettger, of Frankfort, who informed us that it was
quite new to him, but was near Z. paiustris^ var. diluviana^
and this example, with other Ilford shells, was presented to the
Natural History Museum by Dr. Corner. It is to be hoped
that more examples of this form may yet be found.

Vitrea nitidula has hitherto been unrecorded from Ilford.
This species is known from the Pleistocene of Barnwell, of north-
east London, and from Copford. It has been recorded from Grays
by Mr. S. V. Wood, but no examples can be traced.

All the examples of Corbicula fluminalis from Sam's Green
pit are immature. An example of the dwarfed form of Limncta
palustris^ which occurs in the Pleistocene of Harwich and Cray-
ford, is in Mr. Hinton's collection.

Planorbis vortex is only represented by two examples ; whilst
P, spirorbis is the most abundant of the genus. Valvata piscinalis ^
so abundant at Grays, Crayford, and other Pleistocene localities^

PLEISTOCENE NON-MARINE MOLLUSCS OF ILFORD. 285

is only represented by four examples of the normal form. The
variety known as V, antiqua^ Sby., has not been met with. The
characteristic Pleistocene forms, Planorbis glaber and Pisidium
astartoideSy are also of great interest

The occurrence of a single example of Limnaa glabra is of
the greatest importance. This species is at the present day a
widely-distributed form in these islands, but it has not hitherto
been recorded fossil. It was unlikely that so widespread a form
should be a recent introduction, and the Ilford example enables
us to fill up a gap in the geological record.

It will thus be seen that recent work in this well-studied
locality has greatly added to our knowledge, and we trust that
the good work may be extended to other Pleistocene deposits, and
so enable us to present an accurate list of their contained fossils.

[Since this paper was read Mr. J. P. Johnson has called our
attention to a large series of mollusca in his collection, obtained
at Uphall. There are thirty-one species represented, of which no
less than fourteen are new records, viz. :

AgrioUmax agresHs {yivciv\,) Clausilia bidentata (Strom.)

Vitrea crystallina (Miill.) „ laminata (Mont.)

Arion ater^ Linn. Succinea eiegans^ Risso

Punctum pygmaum (Drap.) Planorbis glaber^ Jeff.

Pyramidula rotundata (Miill.) Paludestrina marginata (Mich.)
Helicella itala (Linn.) „ ventrosa (Mont.)

Helix hortensiSy Miill. Valvaia crisfata, Miill.

There are five other species of which, though previously
recorded from Uphall, no other examples are known to be
extant, viz. :

Pupa muscarum (Linn.) Ancylus fluviatilis (Miill.)

Carychium minimum (Miill.) Limnaa auricularia (Linn.)

Spharium corneum (Linn.)

Arion ater is indeed an interesting find, because it is a new
record for the English Pleistocene, though it is known from deposits
in France of the same age, and we have recently found it in several
English Holocene beds. Agriolimax agrestis is now known from
Ilford, Grays, and Crayford.

Punctum pygmaum is rare in any deposit, though it has
been found at Copford, Barnwell, and West Wittering, in beds
probably of Pleistocene age.

The occurrence of a single example of Helix hortensis
furnishes additional proof of the presence of this form in this
country in Pleistocene times. Paludestrina marginata is one of
those species now extinct in this country which are of great
interest It occurs at Grays, but so far has been undetected at
Crayford. The examples of Spharium corneum are of the form so
common at Crayford and known on the Continent as Spharium
mananumy Kobelt.

286 PROCEEDINGS.

The presence of several examples of Paludestrina ventrosa is
noteworthy as tending to support the theory of more estuarine
conditions than now exist. The numbers of species given above
are of course materially altered by these new records.

We are greatly indebted to Mr. Johnson for his kindness in
placing his collection at our service.]

ORDINARY MEETING.

Friday, 3RD November, 1899.

J. J. H. Teall, M.A., F.R.S., President, in the Chair.

The following were elected Members of the Association r

F, Coutts Antrobus, H. Arnold-Bemrose, M.A., F.G.S., W. B.

Bannerman, F.L.S., F.G.S., James R. Brown, J. Herbert Hodd,.

F. Praed, H. Alfred Roechling.

The meeting then resolved into a Conversazione, and the
following is a list of the exhibitors and their exhibits :

The Director-General of the Geological Survey: Sheets
155, 248 (Drift and Solid), 282, 300, 315, 349, and 350 of
the Geological Map of England and Wales, and Sheets 19,
85, and 115 of the Geological Map of Scotland.

J. J. H. Teall, M.A., F.R.S. : Corundum from Scotland.

W. P. D. Stebbing, F.G.S. : The Association's Album of Geo-
logical Photographs ; Crocidolite from S. Africa, Tertiary
Ironstone from Fry the Park, near Epsom, and silicified
Wood from Arizona.

A. E. Salter, B.Sc, F.G.S. : Erratic igneous Rocks, consisting
of Dolerites (Diabases), Rhyolites, etc., and microscopic
slides of the same, from the Lea Valley, Cromer, Derbyshire,
and various other localities.

Dr. G. Abbott : Various types of Concretions in Limestone, Iron,
and Silica.

A. K. CoOMARA-SwAMY, F.G.S. : Corundum and other minerals
from Ceylon, Sections of Rocks from Ceylon and Brittany,
and Cambrian Fossils from Skye.

W. H. Chadwick and Percy Emary, F.G.S. : A series of Grap-
tolites from the Wenlock Shale and Llandeilo Beds of Builth
and Llandrindod, and from the Llandeilo Beds of Abereiddy
Bay, near St. David's.

Prof. T. G. Bonney, D.Sc, LL.D. : "Dreikanter" (windwom
stones) from Egypt and New Zealand ; and Schistose
Jurassic rocks with minerals mistaken for garnets and stauro-
lites, etc., from the Alps.

F. A. Bather, M.A., F.G.S. : A quartzite Pebble from a Drift at
Bowdon, Cheshire, with three facets on one surface (the pro-
perty of R. D. Darbishire, Esq.); also similarly shaped pebbles
from near Reval in Esthland, from Hokitika, New Zealand,.
February, 1900.]

PROCEEDINGS. 287

and from Prague, composed of various materials, but all
known to have been sculptured quite recently by the erosive
action of wind-blown sand

Miss C. A. Raisin, D.Sc. : Specimens and microscopic sections
of Granite and contact metamorphic Rocks from Barr-Aodlau»
Vosges ; Enstatite Serpentine and gametiferous Serpentine
from the Vosges ; and Lavas, Volcanic Bombs, and Sand-
stone fragments with vitrified surfaces from the Eifel.

Rev. Prof. J. F. Blake, M.A., F.G.S. : A series of English and
Indian Trigonia,

Miss M. C. Foley, B.Sc : Carboniferous Limestone Fossils,
Dolerite and associated rocks, etc., collected during the
Derbyshire Excursion (August, 1899).

W. F. Gwinnell, B.Sc., F.G.S. : Red Chalk of Hunstanton, with
photographs and drawings; and Miocene Fossils from the
Faluns of Touraine.

Henry Preston : Fossils from the Red Chalk of Hunstanton.

W. Whitaker, B.A., F.R.S., Pres. G.S. : An album of photo-
graphs of the members of the Socidt^ Beige de G^logie^
Paldontologie et Hydrologie, being a pleasing memorial of
their recent visit to this country and of the excursions in
which they took part, some of which were arranged by the
Association.

J. Parkinson, F.G.S. : A senes of volcanic rocks from Vesuvius
and the Naples district, and photographs of Vesuvius,
including some taken during the eruption of 1872.

Francis R. B. Williams : A section across England and Wales>
by William Smith. Published by John Carey in 181 7.

W. H. North : Memoir descriptive of William Smith's Geological
Map of England and Wales published in 18 15.

John Sheer : Pebbles showing two infiltrations and faulted veins
from near Boscastle, North Cornwall, Palceolithic Implements
from Sussex, and a quartz geode from the beach at Worthing.

A. S. FooRD : Photographs of frescoes in the Historical Museum
at Moscow, representing life in Russia during the Stone
Age, etc.

H. W. MoNCKTON, F.L.S., F.G.S. : Photographs taken in Norway
and Dorsetshire.

A. Smith Woodward, F.L.S., F.G.S. : Remains of skin and
skull of Neomylodon listai from a cavern near l^st Hope
Inlet, Patagonia. (Exhibited on behalf of Dr. F. P. Moreno,
Director of I^ Plata Museum.)

Miss Caroline Birlev : A fine series of Carboniferous Lime-
stone Cephalopoda from the Isle of Man, including some
large specimens oiAciinoceras, SoUnocheilus^ and Proiecanifes.

H. W. Burrows, A.R.I.B.A. : MoUusca from the Faluns de
Touraine (Helvetien Inferieur).

G. E. DiBLEV, F.G.S. : Hippurites from the Chalk of Cuxton and

288 PROCEEDINGS./

Rochester (zones of Rhynchonella cuvieri^ Terebratulina
gracilis^ and Holaster planus), Goniaster embedded in flint
from the Middle Chalk of Cuxton, and other fossils from the
Chalk and Lower Lias.
P. A. B. Martin : Chert implements from Broom, Dorset, and
flint implements from France and Spain.

ORDINARY MEETING.
Friday, December ist, 1899.

J. J. H. Teall, M.A., F.R.S., President, in the Chair.

The President referred in sympathetic terms to the loss
sustained by Geological Science and by the Association in the
death of its former President, Dr. Henry Hicks, who for many
years had taken an active part in furthering the objects and
interests of the Association.

The following were elected members of the Association •
Samuel Alsop, Mrs. H. Arnold-Bemrose, Henry Bassett, G. E.
Blundell, Charles G. Cullis, C. J. J. Fox, H. G. Graves, Russell
F. Gwinnell, W. J. Hall, C. R. Hewitt, H. Honwink, Miss J. A.
Lee, Miss Susanna Lehmann, Miss F. M. G. Micklethwait, H. S.
Romer, Major B. M. Skinner, H. W. G. Williams, Rev. E. H.
Woolrych, F.R.G.S.

The following paper was read :

•* The Zones of the White Chalk of the English Coast. I.— Kent and
Sussex," by Dr. A. W. RowE, F.G.S.

The paper was illustrated by diagrams specially prepared by
Mr. C. Davies Sherborn, showing the distribution of the zones in
the coast sections referred to in the paper.

A paper by Mr. W. H. Wickes on " A New Rhaetic Section at
Bristol " was postponed.

ORDINARY MEETING.
Friday, January 5TH, 1900.

J. J. H. Teall, M.A., F.R.S., President, in the Chair

The following were elected members of the Association :
John Chadwick, C.E., Walcot Gibson, F.G.S., Edmund W.
Janson, Philip Lake, M.A., F.Ci.S., Prank M. Moir, James
Parsons, B.Sc, John Scames.

Mr. R. Holland and Mr. J. E. Piper were elected Auditors.

The following paper was read :

"A New Rh^tic Section at Bristol," by W. H. Wickes.

In the unavoidable absence of Sir Archibald Geikie through
illness, Mr. F. W. Rudler delivered a lecture on "The last
great eruption of Etna," illustrating his remarks by lantern slides
and diagrams.

Mr. G. E. Dibley exhibited a flint with plates of Fentacrinus
from the Chalk of Cuxton, and Chalk pebbles from the wash-mill
at a cement factory at Strood.

289

THE ZONES OF THE WHITE CHALK OP
THE ENGLISH COAST.

By Dr. ARTHUR W. ROWE, F.G.S,

I.— KENT AND SUSSEX.

WITH APPENDICES BY PROF. J. W. GREGORY, D.Sc., AND
DR. F. L. KITCHIN, M.A., F.G.S.

THE CLIFF SECTIONS BY C. DAVIES SHERBORN

(Platbs Vlll, IX, XX

{Remd Decgmtber tst^ 1899.]

CONTENTS.

PAGB

Introduction 290

Summary of Zones, with Lithological Features and

Zoological Characteristics 29a

Part I.

COAST OF KENT.

A. Gore End (Birchington) to Kingsgate

Zone of MarsMpiies Usiudinarius 294

B. Kingsgate to St. Margaret's Bay

Zone of Micros ter car-anguinum 301

C. St. Margaret's Bay to Shakespeare's Cliff . . 305

Zone of Micraster cor-Ustudinarium 306

Zone of Holaster planus 310

Zone of Ter ehratulina gracilis 315

Zone of Rhynchotulla cuvieri . . . 'SIT

Secti >n in Langdon Stairs 320

Measurements of the Zones in the Kent Coast . . 320

Part II.

coast of SUSSEX.

D. Eastbourne to the Cuckmere 321

Zone of RhynchofuUa cuvieri 323

Zone of Terebratulina gracilis 324

Zone of HolasUr planus 325

Zone of Micraster cor-testudinarium 327

Zone of Micraster cor-anguinum 329

E. The Cuckmere to Seaford Head 333

Zone of Micraster cor-testudinarium 335

Measurements at Seaford Head 336

(For reference to the zones of Marsupites testudinarius
and Actinocamax quadratus at Seaford Head,
sec Section F.)

F. Newhaven to Brighton 336

Zone of Actinocamax quadratus 339

Zone of Marsupites testudinarius ... , 346

Measurements of the Zones in the Sussex Coast . . 350

Sheets of 6-inch Maps Employed (Ordnance Survey) . 35a

Conclusion 3So

Appendix (A) 353

Appendix (B) 355

List of Fossils from the Kent and Sussex Coasts . 35^
February, 1900. J

290 DR. ARTHUR ROWE ON THE ZONES OF THE

INTRODUCTION.

THIS paper is written by a field-worker for the use of field-
workers, and in it no place can be found for long detailed
stratigraphical sections, for descriptions of the microscopical
characters of the rocks, and their chemical composition, or for
general surveying. This can well be left in the more capable
hands of the Geological Survey.

The writer pins his faith to Zoology, and to Zoology alone ;
for while it is true that broad lithological features give us a natural
division-line between certain zones in some localities, it is equally
clear that these same features fail us, in the case of identical
zones, in other districts. But the fossils never fail us, if we
collect with sufficient care, and as Murchison said in one of his
unpublished letters, " palaeontology carries the day."

No attempt will be made to crowd all the lithological details of
a long coast-line, such as that at Dover or Beachy Head, into a
small sectional diagram, as the overloading with details confuses the
mind ; and very often details, which are true at one part of the
section, are misleading in another part. Where necessary, all
salient lithological features will be noticed. A section along the
coast has been prepared by Mr. Sherborn, wherein the dip of the
beds has been indicated, and all prominent features on the cliff-
top and shore-line have been noted, so as to serve, at the same
time, the office of a 3-inch map. With this in hand, a field-
worker can walk round the coast, and pick up the succession of
beds with ease.

As this paper is the first of a series on the English Coast-
sections, it would be well to define the life-zones in the first
instance. Anyone reading the paper will know, at the outset, what
the writer means, even though the conclusions herein set forth may
not meet with his approval.

SUMMARY OF ZONES, WITH LITHOLOGICAL FEATURES
AND ZOOLOGICAL CHARACTERISTICS.

The zones discussed in this paper are as follows, in descending
order, the typical fossils being printed in column :

Zone of Actinocamax quadratus.

A firm marly chalk, with marl-bands and lines of nodular and
tabular flints. The dominant fossil is Cardiaster pillula^ though the
Belemnites are generally considered to be the most characteristic

a, Actinocamax ( BeUmnitella) quadratus in upper part ) C pillula

b, Actinocainax {BeUmnitella) tnerceyi in lower part J throughout

WHITE CHALK OF THE ENGUSH COAST. 29 1

Other characteristic fossils are Trochosmilia {Coclosmilia) laxa^
Bourgueticrinus (a special formX Echinocorys vulgaris var. gibbus^
and certain Bryozoa.

Zone of Marsupites testudinarius.

It will be impossible to draw up a scheme which shall embrace
all the lithological features of this zone throughout the coast
The chalk varies from the pure flintless chalk of Margate to a
marly, flinty rock, which one cannot distinguish from that of the
zone above. The dominant fossils also vary so much in different
districts that one can only give the broad divisions, which never
vary.

a. Band of Marsupites testudinarius ) zone of Marsupites

b. Band of Uiniacrinus 3 testudinarius.

Characteristic fossils common to most sections are CaryophyUia
4yiindraaa^ Bourgueticrinus (a special form), Echinocorys vulgaris
▼ar. pyramidatus^ Terebratulina rowei* Ammonites leptophyllus^
Actinocamax merceyi^ and Actinocamax verus.

Zone of Mtcraster cor-anguinum.

Firm white chalk devoid, as a rule, of marly veins and bands,
and invariably set with r^ular bands of nodular flint. Tabular
flint lines rather commorL

a. Micraster cor-anguinum upper two-thirds.

b, Micraster precursor ) of group-form pe- ) j , . ,
Micraster cor-testudinarium j culiar to this zone j ^

Other characteristic fossils are Echinocorys imigaris^ Echino-
conus conicus^ and Epiaster gibbus.

Zone of Micraster cor-testudinarium.

Uniformly in all sections a hard nodular chalk, with marly
veins and pockets, and bands of hard, yellow chalk-nodules at
intervals. Flints in irregular nodular bands, with occasional thin
tabular bands. Marly bands rare.

Micraster pracursor ") of group-form peculiar

Micraster cor-testudinarium j to this zone.

Other characteristic fossils are Holaster placenta^ Echinocorys
vulgaris var. gibbus^ Cidaris serri/era^ and certain Bryozoa.

• iJescriLcti in .Appendix B.

292 DR. ARTHUR ROWE ON THE ZONES OF THE

Zone of Holaster planus.

A hard, nodular chalk with marly veins and pockets, and hard^
yellow, nodular chalk-bands ; frequently with brown and green
phosphatic nodules, and green grains of glauconite. Chalk- Rock
may, or may not, be present. Flints in irregular nodular bands.
Marly bands rare.

Holaster planus,

Micrasier pracursor^ ) of group-form peculiar

Micraster cor-testudinarium^ ] to this zone

Micrasier ieskei,

Micraster corbovis.

Other characteristic fossils are Pentacrinus sp., Cardiaster
ananchytiSy Cidaris serrifera, Cyphosoma radiaium^ Echinacorys
vulgaris var. gibbus^ Holaster placenta^ Terebratula carnea^ Tere-
bratulina gracilis^ Rhymhonella cuvieri^ R, plicatilis var. octopUcata^
Turbo gemmatus, and Pleurotomaria perspectiva. When present,
which is by no means the rule, cephalopods and gasteropods
are very characteristic.

Zone of Terebratulina gracilis.

A hard, white, marly chalk, with numerous marl-bands, and
hard, nodular, chalk-bands. Nodular flint-bands may be rare, or
very common. Tabular flint-lines rare.

Terebratulina gracilis,
Micraster cor-bovis,
Hemiaster minimus,
Inoceramus labiatus.

Other characteristic fossils are Holaster planus ^ Holaster
placenta^ Discoidea dixoni^ Echinoconus subrotundus^ and Rkyn-
chonella cuvieri.

Zone of Rhynchonella cuvieri.

A hard, white, marly chalk, with hard nodular beds. Usually
a flintless chalk. In the lower part of the zone the chalk is
intensely hard, and gritty from broken fragments of fossils,
forming, in most instances, the characteristic " grit-bed." Marl-
bands rare.

Rhynchonella cuvieri
Inoceramus labiatus

> common throughout.

Other characteristic fossils are Discoidea dixoni, Echinoconus
subrotundusy Echinoconus castanea^ Hemiaster minimus^ Cardicuier
PygmceuSy Glyphocyphus radiatus^ Ammonites cunningtoni^ and
Ammonites peramplus.

WHITE CHALK OF THE ENGLISH COAST.

293

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294 DR. ARTHUR ROWE ON THE ZONES OF THE

PART I.

Coast of Kent.
A, Gore End (Birchington) to Kingsgate.

Zone of Marsupites testudinarius.

In the case of the Thanet Coast the danger of being caught
by the tide is very small. Many parts may be worked even at
high tide, and the " gaps " on the shore are so numerous that
escape can easily be made. The only really dangerous place is
west of Collins' Gap, between Margate and Westgate, and at the
east end of Westgate itself. Here the tide rises very high, and
comes up with great speed. Two other places to be mentioned
are White Ness, at the east side of Kingsgate, and the section
between Ramsgate and Pegwell, where there are no gaps, and
where the shore is in places of a very soft and treacherous
nature.

The only papers which will be quoted in reference to the
Thanet Chalk will be Dr. Barrois'* famous '*Recherches " and
that published by Mr. Bedwell in the Proceedings, as none of
the others deal with the subject from the zonal standpoint. Mr.
Bedweirst observations on Ammonite distribution are so
accurate, and have been of so much value to zonal workers in
Thanet, that it is a source of regret that his investigations were
limited to these two papers. The line of scattered flints is the one
prominent lithological feature in the Thanet Marsupit€S<\\z}^y
and, to mark our indebtedness to the author, it will be alluded to
in this paper as the " Bedwell-line."

Starting from the west end of Gore-end Bay, the cliffs are only
about 25 ft. high, and 1 5 ft. from the base is seen a thin and ill-marked
line of nodular flints. This is the ** Bedwell-line." It is by no
means easy to follow this line, as it is often interrupted, and in
some places it is quite as easy to follow the line of the Ammonites
themselves, as in this part of the coast they extend nearly up to
the flint-line. In following the "Bedwell-line " a valuable aid will
be found in a yellow sponge-bed, which occurs with considerable
constancy two or three feet below it, and can be traced throughout
the section.

The " Bedwell-line " rises as one goes east, until it is 20 or 25 ft.
up the cliff" at Westgate Bay, and still higher in the little headland

• ** Recherches sur le terrain cr^tacd sup^rieur de I'Angleterre et de I'lrlande, 1876."
t F, A. Bedwell, *' Ammonite Zones of the Isle of Thanet," Proc. Gtol, Astoc.t vol. iii,
No. 5, April, 1874 ; GtoL Mag,^ dec ii, vol. i, p. x6, 1874.

WHITE CHALK OF THE ENGLISH COAST. 295

which diirides the last-named from St. Mildred's Bay. It almost
reaches the top of the cliff between St. Mildred's Bay and the
Royal Sea-Bathing Hospital. At the latter point the cliflfs become
very low, and the flint-line drops rapidly. The clifls appear again
at Fort Point, Margate, and here the " BedwelMine " is 40 ft. up
the clifi*. From this point it gradually sinks until it reaches 30 ft.
at Hodges' Flagstaff, and falls to the shore-line at Foreness Point,
to rise again beyond the sewer outfall, until it reaches White Ness
Point (68 ft high), where it passes out at the top of the cliflf, and is
seen no more until we pick it up again at Pegwell. The only point
where it is lost is in the low cliffs of Botany Bay, where it
temporarily passes out at the top of the cliff on the north side, to
reappear, as the cliff rises, on the other side of the bay. At
Pegwell we see it again for about one-third of a mile, when, after
passing through a series of faults, it suddenly drops to the shore-
line, and sinks into the sand.

"Barrois' sponge-bed," which forms the base of the Mar-
supitcs'zou^ rises from the sand on the south side of White Ness
Point, and is 21 ft above "Whitaker's 3-inch" tabular flint-
band, which rises from the shore under Kingsgate Castle. The
association of these two lithological features will be traced when
we deal with the zone of Micraster cor-anguinum. For the
moment, sufice it to say that they can be followed, where the
cliffs are high enough, as far as the north-east side of St
Margaret's Bay. The band of Echinoconus conicus lies imme-
diately above " Barrois' sponge-bed " on the south side of White
Ness Point.

The importance of the •* Bedwell-line " as a lithological
feature marking a zoological break will be seen in the zoological
summary on page 296. Speaking broadly, AcHnocamax merceyi and
Marsupites testudinarius do not occur below it, and Uintacrinus,
Ammonites leptaphyllus^ and AcHnocamax verus do not pass above
it When Bedwell discovered the important relationship of the
flint-line to the Ammonite-bed, he had no idea of its relationship
to the equally important zonal fossils. It would be absurd to
imagine that the "Bedwell-line" forms a hard-and-fast line of
demarcation, for we know that life-forms begin gradually, and
die out gradually.

The MarsupiU5^<^asi}^i is one of the typical beds of the
"Chalk with numerous flints" of the older writers; but in
not a few districts it is almost flintless.* The chalk \& soft
and holds much moisture, and can easily be worked with a
pocket-knife. No marl is found either in veins or bands, and, in
consequence, the fossils can be cleaned, wet or dry, with equal
ease, and beautiful results may be obtained by working them out
with the dental-enginet The flints are solid and black, with a

* It is practically a fllntless chalk in Thanet.

t A. W. Rove, Natnrmi ScUmct, voL ix, No. 57, NoTcmber, 1896.

296

DR. ARTHUR ROWS ON THE ZONKS OF THE

thin white cortex. A notable general feature of this chalk
is the lines of vertical jointing, which run north-west
and south-east The coast is riddled with caves, all due
to the jointing. From Birchington to Margate the chalk
is very much broken up, but in the remainder of the
section it is more compact. The beds rise as we trace them
from Foreness to Ramsgate. This is the finest section of
MarsupiteS'C\iiX)ii in existence, and the sandy shore and the
abundance of gaps make the working of it peculiarly easy.
There are no less than seven miles of this comparatively rare bed,
all in excellent condition for working.

The Broad Zoological Divisions of the Zone of
Marsupites testudinarius.

a. Marsupites testudinartus
Actinocamax merceyi
EcAimocorys vulgaris var. pyramidatus
Bourgueticrinus (a special form)
Tereiratulina rowei

Band of

Marsupites

testudinarius ^

48 ft. exposed,

the *' Bedwcll-line."

b. Band of Echinocorys vulgaris^ var. pyramidatus,
Uintacrinus x
Actinocamax verus 1 Band of
Ammonites leptophylbis (^ Uintacrinus^

c. Echinocorys vulgaris var. pyramidatus I total thickness,
Bourgueticrinus (a special form) 1 86 ft.
TerebratuHna rowei *

d. Band of Echinoconus conicus,
vwwvwwvvvwvwvvwwvvvwvv **Barrois' sponge-bed",

the base-line of the

Zone of
- Marsupites
testudinarius
116 ft.

Other characteristic fossils are PorosphcBra^ Cyphosoma kdnigi^
Micraster cor-anguinutn var. rostratuSy Zeuglopleurus rowei*
Serpula turbineiia^ Rhynchonella plicatilis, TerebratuHna rowet,
Kingena limay and Lima hoptri.

It will now be well to examine more closely the mutual rela-
tionship of the chief guide-fossils in this zone, and they will be
discussed seriatim,

Marsupites testudinarius is essentially a gregarious fossil, for
when it is found, it is found abundantly. It has been collected
from the top of the cliff at Foreness Point, 48 ft. above the " Bed-
well-line." The lowest record is that of a perfectly smooth test,
found 30 ft. below that line, at Hodges' Flagstaff. It can be
collected anywhere along the section in fallen blocks from the top
of the cliff, but the best results will be obtained at Gore- End Bay,
east of Collins' Gap, and especially at Foreness Point. At these
localities the " Bedwell-line " sinks near the shore, and the fossil
comes within reach. For this reason we can generally find plates
for 200 yards west of the target. The great storm of November,
1898, brought down much chalk from the top of the cli£^ and

* Described in Appendix A.

CMAUL or xm mwarai coasx.

i cooid then be foqnd m abfrrirtiinrr aH aloog tiie
I on tbe £dfen blocks^

In Tbinct,aII the ciiidence pocots to die niitfmrr ol die
smoodi and small plates in die base of die Jfiorsttfttes^mnd, and
die carl J sporadic oocuneDces in die CimliKrams-band point in
thesamcdueuiuu. Wbece the piates are largest and most abnndaat,
there the omamentanoo is most markfri, It would also seem
that the plates become smaller azid smoother again before thcf
die oat, thoogh the data on this point are not so abondant aiMl
coodnsiYe. Moch the same appears to occor in the Sosmx
Chalk. We hame aeter found Mixyfupita in the aone of
Adinoccumax qmadraius.

Aaztwtmmax w^grceyL — Field-workers owe a debt of gratxtode
to Dr. Barrois for famrljarising this important zonal form (whkh
was founded bf ^layer-EjmarK and for the separation of it from
AcHmoaimax quadnstms. In the secdoos worked bf die writer,
it generally passes down into the Jiarsmfitts-baadj and
occQpies the fower part of the Aiitimocamax qitadratms-vaott.
In this section its range is coincident with that of JioFsmpiia
itself, and it can genoally be foond at Foreness Point, where
the plates are thickcsr. Hany roOed eaamples maj be pk^ed
up on the rce6. The kswest record was at Newgate Ga^k^ 30 ft.
bdow the "^ Bedwril-Iine." It is not a coomion fossil in anj
secdon which we have worked. This is not the place to discuss
the anatomical details of the fossil, hot it may be mendooed that
the alTeoIar caTitj is mach shallower tban that of A^timixamax
quadratus, A paper on the Belemnites of the Chalk will shordj
be published by Mr. G. C Crick, in which will be incorporated
all the stratigraphical details obtained on the coasts of Kent,
Sussex, and Dorset.

EMmocorjs vulgaris var. fyramidtitiu is very abundant, and a
thick band with this fossil may be focmd immediately below the
" Bedwdl-line.'' This band is an anvarying feature from Birch-
ii^;ton to Kingsgate. So common and charactehsdc is this
urchin throogfaout the whole thickness of the MarsupiUs-iotut,
wherever it occnrs, that the writer would feel justified in assigning,
by its presence in quandty, any quarry to this zone, even if plates
of MarsMfiies or Uintacrifms were not discoverable A large
dome^haped variety of EMmxorys vulgaris is met with in the
Uimia£rimu-h2ndj and less commonly in the Marsufiles-bamd.
A paper on Eckinccorys is in coarse of preparadon. The
Eckimoc0rjs^3QJM\ is a local feature only.

Bourgu^Hcriftus forms a very useful guide to the whole of
the zone, for wherever the writer has worked, there a certain
form of head is foond. It is nipple-shaped, and not of large
size. (See PL VIII, Fig. 6.) A large barrel-shaped joint is
also characterisdc, but not so in£dlible a guide as the other,
as it is also fiuriy common in the Jfl tar-aMgmimum-uxMt

298

DR. ARTHUR ROWE ON THE ZONES OF THE

The writer has not found the nipple-shaped form outside the
MarsupiteS'Zon^,

A new Terebratulina has been described by Dr. F. L. Kitchin
for this paper. It is found throughout the whole extent of the
zone, wherever the writer has studied it, and though not abso-
lutely limited to it, its occurrence in the zone of AcHnocamax
quadratus is so rare that it may be regarded as a reliable guide-
fossil to the MarsupiteS'Zone. The form found in the zone of
A. quadratus differs so decidedly from that in the zone below
that it would never mislead in the field. (See Appendix B,
PL VIII, Figs. 1.5.)

Uintacrinus. — The whole of the base of this section is in the
C/infacrinus-hsind, save the short portion at Foreness Point, where

the Marsupites-hzxid comes down
to the shore-line. Its range is
from the "Bedwell-line" to about
20 ft. above "Barrois* sponge-bed."
Occasional plates may be found
below the point mentioned, but it
has never been found right down
to the base-line of the Marsupites-
zone in Thanet. It is a common
fossil — as common as Marsupites is
in its own band. As would be
imagined, it mingles with the Mar-
supitesy and plates belonging to
both genera have been found on
the same block of chalk by Mr.
Sherborn, Mr. Upfield Green, Dr.
F. L. Kitchin, and the writer.
This fact is especially mentioned,
as doubt has been expressed on
this very point. The broad fact
remains that where Marsupites is common, Uintacrinus is rare,
and vice versd.

It would be difficult to exaggerate the importance o{ Uintacrinus
as a guide-fossil, for wherever we have worked this zone, there
Uintacrinus has been found in its proper position in the
lower part. It may be mentioned that we are never content
to determine this zone by means of the arm-ossicles, but always
rely on the plates of the test. The arm-ossicles are characteristic
enough, but may be confused with those of Marsupites^ Ophiura^
or broken columnals of Bourgueticrinus, Nothing is like the ir-
regular, polygonal Uintacrinus plate, with its strong ridges
on the inner concave surface. This crinoid has proved to be
one of the most important guide-fossils discovered during the
last twenty years. The writer collected it twenty-five years
ago, and was quite unaware of its generic name until Mr. F.

Uintacrinus from Margate ;
several plates in the natural
position ; natural size. C, cen-
trale ; B, basals ; R, radials ;
IBri, first primibrach ; I Ax,

frimaxil ^ second primibrach ;
I Br I, first secundibrach ; iBr,
interbrachials. The detached
plate is a radial, from Westgatc,
viewed on the inner surface.
Coll. A. W. Rowe. Gilbert C.
Chubb del. ; F. A. Bather dir.

WHITE CHALK OF THE ENGUSH COAST. 299

A. Bather* named the specimens sent up to him. It was then
merely a matter of time to define its range, and gauge its zonal
value. (See Fig. on p. 298.)

Actifwcamax verus is a common fossil throughout the Uinta-
crifutS'ha^d^ and it extends a good many feet above the " Bedwell-
line," where Marsupites are abundant, but it then becomes rare.
Its downward range is to the " Barrois sponge-bed," in which it
has actually been found, but the writer has never found it below
that level in Thanet, nor in the zone of Micraster cor-anguinum in
any other locality. When it occurs, it is found abundantly, as a
rule, but it is one of the unreliable factors of the zone, as it does
not occur in every section. (See p. 348.)

Ammonites leptophyllus, — The range of this fine Ammonite is
identical with that of Uintacrinus^ and the fact that 105 were
found, in situ^ between Birchington and Kingsgate, proves that it
is not rare. (The reader is referred to Mr. BedwelFs paperf for
further information.) It rarely measures more than 3 ft. in
diameter in this part of the Chalk. Its upward range is to the
" Bedwell-line," only four examples having been found above that
level, and then but a few feet above it. It has not been found
within 15 ft of the " Barrois sponge-bed." Aptyckus has not yet
been found in Thanet, nor did we meet with it in the zones of
Marsupites or Actinacamax quadratus in Sussex.

Echinoconus conicus^ though by no means confined to this zone
or diagnostic of it, must be mentioned, as it occurs as a thick
band above the *' Barrois sponge-bed," through which it passes
into the zone below. The upward range is to the Marsupites-
band, but it is a rare fossil above the " Bedwell-line." Dr.
Blackmore says that, at Salisbur>', it is common at the base of
the .\farsupit€szo\\e^ though it does not form a band as it does
in Thanet. At the south side of White Ness Point the Echinoconi
are so thickly packed that they are crushed one into another.
Echinoconus ghhulus is found in Thanet at the base of the
yfarsupites-zon^j and at the extreme top of the M. cor-anguinum-
zone. We have not found it in Sussex or Dorset. It is a rare
fossU.

Porosphara is a useful guide-fossil. All three forms are
common, and Porosphara globularis reaches its maximum size in
this zone. The large size of this form is a useful fact to know in
the field.

Caryophyllia cylindraaa is not a common fossil, but it is
characteristic of the zone in Thanet, and at Salisbury also,
according to Dr. Blackmore. At present we have not found it
in Sussex. Paras mil ia centralis is the usual form, and is
fairly abundant, but it is not reliable as a guide-fossil. The corals
in this zone are rarely of large size. Parasmilia granulata is

* G€»l. Mmg.^ N.S., decade iv, voL iii, pp. 443-445, Oaober, 1396.

300 DR. ARTHUR ROWE ON THE ZONES OF THE

found, but is not so common as in the zone of MUraster
cor-anguinum.

A new ZeuglopUurus has been described for this paper by Dr.
Gregory. It occurs both above and below the " Bedwell-line " in
Thanet, but has not been found at present in other sections of
the MarsupiteS'ZOTit, (See Appendix A, Figs. 1-4, p. 354.)

Salenia geometrica is never really common, though we have
found a fair number of specimens in the Marsupites-zjont^ at
Margate, especially in the C/in/acrinus-b^nd. It is still rarer in
the zone of M. cor-anguinum, and rather more common again in
the Actinocamax quadratus-Txmt,

Micraster cor-anguinum var. rostratus — the M, rosfratus of
Mantell and Bucaille — occurs in this zone. It is not a species,
but merely a zonal variation, with an exaggeration of the strong
carination characteristic of the high-zonal series of Micraster,
It is, however, of use to us as a guide, and as such it is here
recorded.

Serpula turbinella^ though by no means confined to this zone,
is a characteristic fossil, and is commoner here than in the zones
immediately above or below it.

Rhynchomlla plicatilis is only found at the lower part of the
Uintacrinus-h^nd in Thanet, and is there a rare fossil. This is in
marked contrast to its abundance throughout the whole zone in
Sussex, especially in the Marsupiies-hznd,

Kingena lima^ of a small, round variety, is fairly common
throughout the zone, and is useful, as it is very rare in the zone
of Actinocamax quadratus^ and is far from common in that of
Micraster cor-anguinum. This form differs considerably from the
large examples found in the zone of Belemnitella mucronaia.

Ostrea aiceformis, Woodw. (Woodward's "Geol. Norfolk," pi. vi,
figs. I, 2, 3), is not uncommon in this zone in Thanet. VVe have
seen no figure which exactly reproduces these forms from the
Marsupites-zont^ but they more resemble Woodward's figures, and
Norwich {B. mucronata-zone) specimens, than any others. We
have seen a variation of this form in the zone of A. quadratus^ and
it is probable that a series of zonal variations could be traced from
one zone to another.

Lima hoperi is found throughout the zone in abundance, and
is of very large size. In the writer's experience no other zone
yields them in such numbers, or of such size.

A reference to the section of the Coast which accompanies
this paper will show that letters have been used to indicate
the position of the chief guide-fossils in this zone.

It has been objected that the name-fossil of this zone is not
well chosen, and that this zone should be merged with the Actino-
camax quadratus' and Belemnitella mucronata-zones above it. If
ever a zone possessed a distinctive fauna it is the zone of
Marsupites testudinarius. The main difliculty is that field-workers

WHITK CHALK OF THE ENGLISH COAST. 30I

do not recognise that the AfarsttpiUs-hsind is only a part of the
AfarsupiUs'Zoney just as the equally important Uim/acrinus-bsind
is but a portion of it. It has been said that it should be merged
into the A, quadratus-zon^ because Actinocamax merceyi passes
down from the higher zone into the MarsupUesAmnd, The obvious
reply to this is that the other guide-fossils of the A, guadrafus-zone,
such as the all important Cardiasttr piiluia, and the equally
characteristic Echinocarys vulgaris var. gibbus^ are limited to their
own zone, and do not follow the downward range of Actinocamax
merceyi. Moreover, there are sections of the A, quadratus-zont
where Actinocamax merceyi is not found at all.

B. KiNGSGATE TO St. MaRGARET^S BaV.

Zone of Micraster cor-anguinum.

This is a typical section of the " Chalk with numerous Flints "
of the pre-zonal writers, and is of great length ; for omitting the gap
between Little Cliffs End and Kingsdown, we have just ten miles of
this zone, every yard of which is easily accessible, and capable of
yielding good results. The chalk is soft and white, more com-
pact than the Marsupites-cYMi, and devoid of marl. Nodular
flint-bands occur with striking regularity, and tabular flint-bands
are not uncommon. The most interesting of these is " Whitaker's
3-inch'' tabular flint-band, which rises south-east from the sand, under
Kingsgate Castle, 21 ft below " Barrois' sponge-bed," and con-
tinues to rise until it reaches the North Foreland Lighthouse, from
which point to the Coastguard Station at Broadstairs it keeps
nearly horizontal. We pick it up again on the other side of
Broadstairs, and carry it on to the south side of Dumpton Point,
where the clifiis are lower, and the tabular band passes out at the
top. Up to this point the tabular* has been imperceptibly rising
until it reaches three-fourths of the way up the cliff. This takes
us to Dumpton Gap, where there is a fault, bringing the tabular
half-way down the clifi*. Between here and P>ast Cliff I»dge
the chalk is faulted in several places, and the tabular is, in con-
sequence, not quite horizontal The tabular again rises gradually
until, at Augusta Stairs, it is 25 ft. from the top.

There may be, here and there, a very thin cap of the
MarsupiicS'ixmc along the North Foreland, ^xit there cuitwi
be much, as the " Barrois sponge- Ijed ^ can only rarely Ije
seen, and that is 21 ft. above the ** yinch" tal/ular ^jznd;
but from 300 yards south of Dumpt/-^ Gap to Augura .Stairs
we have room for the Clntacrinusifuid at the top of Xht chtt,
and we find evidence of it in the infM:n<j: of '' Barro^v" ^/nge-
bed," and fireqoent fragments td AmmoniUt kpioph}iiui c«i the
shore.

302 DR. ARTHUR ROWE ON THE ZONES OF THE

The tabular band can be traced in the cliff behind the
L.C.D.R. Station, 75 ft. up from the base, and is easily picked
up again in the West Cliff, where it is on a level with the cement
string-course in Paragon Baths. It disappears just where the iron
railings end, by the Liberty Boundary, and at the point where
there are four arched brick supports to the cliff. We now see no
more of it until we come to Pegwell, where we find it in the cliff
at a point corresponding with the letter " H " in " Hotel," on the
6-inch map. It here dips rapidly to the south-west, and a little
west of the Coastguard flagstaff there is a fault where the band
disappears.

From the fault to the junction with the Thanet Sands we have
to deal with the zone of Marsupites^ as the dip to the south-
west brings the upper beds to the shore. Under the flag-
staff the cliff is 30 ft. high, and " Barrois' sponge-bed "is 12 ft.
up. From this point the sponge-bed sinks to the west, and we
soon walk upon the Echinoconus-hajidy and finally on Uintacrinus-
chalk, with its abundant fossils. On the broken, grass-grown
slopes west of the brick tunnel we found a few Marsupites plates
associated with those of Viniacrinus ; so this brings us to the
level of the " Bedwell-line," which, however, is not recognisable.
This short section of Marsupites-i^2^ is a complete epitome of
that found west of Kingsgate, and the stratigraphical details and
the fossils are identical.

There are no more chalk cliffs until we pass Kingsdown.
Half-a-mile north-east of Hope Point the cliffs are about 60 ft.
high, and half-way up we notice the line of flint, 30 ft. under
"Whitaker's 3-inch band," mentioned by Bedwell in the
Geological Magazine, * This is the line from which columns
of nodular flints spring upwards ; but the cliffs are not quite high
enough to admit of the " 3-inch " tabular being seen. However,
at the rifle-range the " 3-inch " tabular comes in again, and
steadily rises until we reach the flagstaff, where it again passes out
at the top of the cliff, to come in once more at Leather Court
Point. Thence it steadily rises till we reach St. Margaret's Bay,
where it is at the top of the clifl. Bedwell's " columnar band,"
underneath it, can be traced the whole way with ease, so that we
are indebted to him for another excellent observation, without
which it would have been impossible to have distinguished the
" 3-inch '* tabular from any other thick tabular.

Up to Leather Court Point the cliffs are based by a turf-clad
talus, and excellent collecting Ynay be done along the top of the
slope. From Leather Court Point to St. Margaret's Bay there is
a shingle beach, and the cliffs are wave-worn. Beyond a few
examples of Micraster pracursor^ Echinocorys^ and Inoceramus, the
cliffs are very barren in this, the lowest part of the zone.

• op. cit»

WHITE CHALK OF THE ENGLISH COAST. ^

303

The Broad Zoological Divisjoss of the Zone of
micraster cor'axguinum.

Micraster cor-anguinum . 1

Echinocarys vulgaris^ of form pecu- j

}> upper three-fourths

> 280 ft.

liar to the zone
Echinoconus conicus

Epiaster gidbus . .j
f of group- 1

Micraster pramrsar I form pe-

M, car-testudinarium j culiar to flower fourth

1^ this zone I

Inoceramus invoiuius . . . j

Other characteristic fossils are Parasmilia^ Onchotrochus
strpentinus^ Bourgueticrinus elUpticus^ Cidaris sceptrijera^ C. clavi-
gera, C. perornata^ Cyphosoma konigi^ and Terebratula semiglabosa.

Fossils are uniformly distributed through the upper three-
fourths of this zone, being perhaps a trifle more abundant at the
top than elsewhere; but die base is nearly always singularly
barren in organic remains, and this fact is so characteristic that a
section with regular bands of nodular flints and a paucity of
fossils can generally be recognised as the basal portion of this
zone.

Micraster coranguinum is chiefly characteristic by reason of its
abundance, though there are not a few sections in this zone where
it is a somewhat uncommon fossil. The var. latior is always
found in this zone.

Echinocorys vulgaris is abundant, and of many profile varia-
tions, two stand out as characteristic of the zone — a tall, dome-
shaped form and an ovate form. The common ovate form is figured
by Wright (Brit. Foss. Echin. Palceoniographical Society, 1864 —
1882) on pi. 77, fig. 8, and the tall, dome-shaped form is shown in
fig. 7 on the same plate. The var. pyramidatus is never seen in
this zone in its full development, even at the top, and we have to
wait until we pass into the zone above to find it. It is true, how-
ever, that the ovate form takes on a pyramidical tendency as we
near the upper border of the zone, just as we have, at the extreme
base of the zone, a trace of the gibbous shape which is so
characteristic of the zone below.

Echinoconus conicus is always abundant, but its varieties in no
way difler from those in the zone above. Its rarity increases the
deeper we go in the zone.

Epiaster gibbus is at its maximum development in this zone,
though it is never an abundant fossil. Very interesting passage-
forms between it and Micraster prcecursor are seen at the base
of the zone.

Micraster precursor and M, cor-testudinarium are only found
in the base of the zone, and for details concerning Micraster

304 DR. ARTHUR ROWE ON THE ZONES OF THE

the reader is referred to the paper on that genus by the
writer.*

Ifwceramus involutus is not common, and is generally confined
to the base of the zone. It is rarely preserved in a perfect state,
and the writer has yet to obtain a complete example.

Porosphara ceases to be of use as a zonal guide at this
horizon. All three forms are fairly abundant, especially Poro-
sphara giobularis. In this zone it is of medium size, and is
abundant in every zone down to that of Rhynchonella cuvieri^ but
it is always of small size. PorosphcBra woodwardi and P, pikolus
are found as low down as the zone of Holaster planus ^ but they are
comparatively rare fossils, especially the Porosphcera woodwardi.

Corals are abundant in this zone, and in our experience,
Parasmilia granulata reaches its maximum development.
Parasmilia cylindrica and P, manttlli are found, and are of a
larger size than in any other zone. Parasmilia centralis var.
gravesana is abundant. The nomenclature of this group is in an
unsettled state, and it is probable that a widely extended zonal
inquiry would materially reduce the number of species, and that
the working of zonal variation would be more clearly emphasized.
But the coral which is most characteristic in the upper part of
the zone in Thanet is Onchotrochus serpeniinus. In the writer's
experience this is shown to be a local peculiarity.

Bourgueticrinus is abundant, and a stumpy head is rather
characteristic, as well as a large and long columnar (PI. VIII, Figs.
8 and 9). The characteristic columnar, however, is a medium-
sized, barrel-shaped form, which is figured.

Cidaris spines are abundant, and Cidaris sceptrifera^ C,
clavigera, and C. hirudo are all common to this zone and the
zone above, though they are found here in great abundance.
Cidaris perornata, however, is certainly more special to this zone.

Cyphosoma konigi reaches its maximum development in this
zone, being rare in the zone of M. cor-testudinariuniy fairly common
in the Marsupites-zon^^ and comparatively rare in the zone
of A,quadratus. Cyphosoma corollare and C spatuliferum have the
same range as Cyphosoma konigi^ and their relative abundance
in the various zones is much the same.

Terebratula stmiglobosa is common in this zone, in singular
contrast to its rarity in the zone above.

Thecidea wetherelli begins to appear at the base of this zone,
but it is rare. Directly we pass into the upper three-fourths of
the zone it becomes abundant, and it ranges up to the B.
mucronafazone, being always a common fossil. We have recently
examined hundreds of Micrasters, from the zones of M. cor-testudi-
narium and H. planus^ and failed to find a single example upon
them. Its downward range, therefore, in Kent and Sussex, would
seem to be sharply defined.

^Qumrt feum* GtcU Soc,^ vol. Iv, August, 1899, p. 494.

WHITE CHALK OF THE ENGLISH COAST. 305

This is one of the least satisfactorily named of the zones, as in
spite of its great thickness, there is so little upon which one can
depend in the matter of fossils which are common, and at
the same time reasonably restricted to the zone in question. Also,
from top to bottom of it, there is no salient lithological feature,
with the exception of the " Whitaker 3-inch band " ; and as that
has no bearing on the faunal history of the zone, its value is
confined to its relation to " Barrois' sponge-bed," and its position
as a guide to the top of the zone in Thanet and at St. Margaret's
Bay. There is no fossil which is entirely satisfactory as a zonal
guide, and therefore the old name has been retained in this paper.
Epiaster gibhus has been suggested, and it is a good guide-fossil,
but far too rare to be of practical service ; besides, it is relatively
almost as common in ^(t Marsupites-TXin^, Echinoconus is found
abundantly, but so it is in the zone above. Echinocorys vulgaris
is incomparably the most reliable form, and the writer is in
the habit of using the shape-variations already mentioned as the
most ready means of determining this zone in the field.

Inoceramus inuohitus has been lauded as a name-fossil, but
chiefly on account of its greater prevalence in this part of the
Chalk in France. A fossil so fragile and imperfect, as this
always is with us, should only be adopted as a last resort ; and
the writer would ask the supporters of the proposed use of this
shell as a zonal name-fossil, how many examples in a decent state
of preservation they have in their cabinets? This is one of the
most colourless zones with which we are acquainted, and the
present name has been retained, not because it is a good one, but
because there is nothing better wherewith to replace it.

The flints in this zone are black and compact, with a varying
thickness of white cortex. They are not commonly " zoned,"
as at Beachy Head, as mentioned by Barrois.

The Survey measurement of 280 ft. has not been checked by
the author, as the upper and lower limits of the zone are so
strongly defined in Thanet that there is little possibility of
error.

C. St. Margaret's Bay to Shakespeare's Cliff.

The Dover section has been admirably dealt with by Mr.
Price* in the west cliffs, and by Mr. VV. Hillf in the west and east
cliff's, and there is another paper by Hubert, J which is interesting
as a pioneer paper on the zonal question.

This section is so important that it will amply repay the
observer to walk round the shore from St. Margaret's to Langdon
Stairs, before doing any collecting. By this means a general

* Onart. /amrn. Geo/, Soc.t vol. xxxiii, 1877, pp. 43x*448.

t lAtd.t vol. xlii, x886, pp. 233-347.

t Bull, S0e. GicL de Fratut^ i*x. 3, t. xi. June 15, 1874.

3o6 DR. ARTHUR ROWE ON THE ZONES OF THE

idea of the position of the zones may be obtained, and
calculations can be checked by examining the beds in succession
during the ascent of the zig-zag at Langdon Hole (see p. 320}.

It may be convenient to know that there is no way up from
the shore between St. Margaret's and Langdon Stairs, and that
there are two points at which the water rises very high, and to
which it runs up quickly. These are at the south corner of St
Margaret's Bay, and at a point a little west of Comhill Coastguard
Station. However, the numerous falls afford a safe refuge, and we
commonly arrange to be caught by the tide ; but one wants to
know the coast before doing this. Strong fresh-water springs are
found all along this coast, notably at St. Margaret's, opposite
Canterbury Hole, at a point north-east of Frenchman's Fall, at the
junction of the Holaster planus- and Terebratulina graciiiszoneSj
and under the convict prison. These springs are on the reefs,
and it is worth noting that wherever they occur the reefs are clad
in a bright green sea-weed.

This is, on the whole, the grandest section from the zone of
Micraster cor-testudinarium to that of Rhynchonella cuvieri in the
south of England, every zone being well exposed, and in good order
for working. From the south corner of St. Margaret's to 200 yards
north-east of the Ix)w Light is two-thirds of a mile, and all this
is in the zone of M. cor-testudinarium , From this spot to the
perpetual spring rising from the foot of the cliff, which coincides
with a point north-east of the windlass at Bantam Hole, the
section is cut in the zone of H, planus^ and from the spring
to Dover the cliff is in the Chalk with Terebratulina gracilis.
The Chalk-Rock rises a little north-east of the submarine tele-
graph, near the South Foreland Light. On the west side of
Dover are some good sections in the zones of T. gracilis and R.
cuvieri^ which can be worked in falls, and examined throughout
their extent in the two zig-zags.

Zone of Micraster cor-testudinarium.

This is the "Chalk of many organic remains" of Phillips
{Trans, GeoL Soc, sen i, vol. 5, p. 24) and Whitaker's "nodular
chalk ofDover"(J/<f/;/. GeoL Survey, 1872, "London Basin,"p. 32).
Both terms are apt, as the rugged, knotty nature of the beds is
very apparent, and the abundance of fossils most striking. The flints
are not in regular nodular bands as in the zone above, but irregu-
lar bands are not uncommon, and scattered flints are frequent.
The flints are often spongiform. There are no marl-bands, but
the chalk is greyish in colour from the presence of marly patches
and veins This chalk is very curious, as we have hard yellow
nodular bands, from which fossils can hardly be extracted, and
soft patches from which they can be removed with a pocket-
knife. The soft marly pockets are very rich in Bryozoa and

WHITE CHALK OF THE ENGLISH COAST. 307

Foraminifenu The whole of the two-thirds of a mile of M, cor-
testudinarium-K^ca^ is in fine condition for working. The cliffs
are tide-washed, but not battered by the shingle, and con-
sequently afford the finest section of this zone in England.

The steady rise of the beds, as we pass round the coast, is
here continued, and at the north-east corner of St. Margaret's Bay,
under a small turf-clad talus, is the actual junction of the zones
of M. cor-anguinum and M, cor-testudinarium.

On the white chalk flats in the bay one can collect
Micraster precursor, M, cor-testudinarium and Echinocorys vulgaris
var. gibbus^ the two first, of the group-form special to this zone, but
bearing clear evidence of their passage to the forms special to the
base of the zone above.

At the south comer of St Margaret's Bay the cliffs are com-
paratively low, and are only 150 ft. high at Canterbury Hole, which
is now obscured by a fall of cliff. We here have nothing but the
chalk of the zones of M, cor-testudinarium and M. cor-anguinum to
deal with, and the contrast between the two beds is very striking —
one grey-yellow and nodular, with irregular lines of flints, the other
smooth and white, with regular lines of flints. An idea may be
obtained of the rate at which the beds are rising by noting that
the junction of the zones of M, coranguinum and M. cor-testudin-
arium^ which is on the shore-line at the north-east corner of the
bay, is 37 ft. above the shore at Canterbury Hole.

At this point, we can count from the shore seven well-marked
yellow nodular-chalk bands, from 5 to 7 ft. apart. The topmost
yellow nodular band marks the junction of the zones of M, cor-
anguinum and M. cor-testudinarium. Above this arbitrary line
the paucity of fossils is as notable as the profusion below.

At the same place is seen a thin tabular flint-line, within the
M. cor-testudinarium-zjont, 1 1 ft. from the shore-line, and a second,
and much thicker one, about 15 ft. above the last yellow nodular
band. These are respectively the M. cor-testudinarium-izb\i\zXj
and the basal M. cor-anguinum-iahu\sLr. Of course, the latter is
quite different to the tabular mentioned before in the same zone.
These two tabulars have been fixed upon, as we can follow them
with ease as far as the zig-zag stairs in Langdon Bay, and with
glasses they could, doubtless, be followed well into Dover. They
are most useful as giving a fixed line, whereby we can follow the
beds as they rise and pass out of easy vision. These two tabular
bands are 44 ft. apart. Taking the Af. cor-testudinarium-Xzbu]zx
as a datum-line, we find that at Frenchman's Fall it is 20 ft. from
the shore-line, and 200 yards north-east of the Low Light it is
30 ft from the shore-line.

Two hundred yards north-east of the Low Light we see three
lines of nodular flint, the highest and lowest strong and continuous,
and the middle broken up into two or three uncertain lines. The
measurement between the highest and lowest lines is 15 ft, and the

3o8 DR. ARTHUR ROWE ON THE ZONES OF THE

distance between the M, car'ttstudinarium'\skx\zx and the upper
of the two strong flint-lines is also 15 ft. We can thus get a
thickness of this zone from the Canterbury Hole to 200 yards
north-east of the Low Light

From the M, cor-Ushti/marium'tsibuisur^ to the last nodular band 26 ft.
„ „ „ to the lower of the two
strong flint-lines 30 ft.

Total 56 ft.

The lower of these two strong flint-lines is the approximate
junction of the zones of M, car-testudinarium and ff, planus.
The actual break is a purely zoological one, and takes place in
the 15 ft. between the upper and lower of the strong nodular
flint-lines, and this arbitrary limit is fixed entirely by careful
collecting, for there is. no definite lithological division. It is only
another instance of the hopeless task of trying to establish hard-
and-fiist lithological boundaries for life-zones, which can only be
settled by evidence ofiered by the fauna itself.

Typical Fossils of the Zone of Micraster
cor-testudinanum.

Micraster pracursor ) of group-form peculiar!

M. cor-testudinarium \ to this zone. \ 56 ft.

Echinocorys vulgaris var. gibbus j

Other characteristic fossils are Cidaris serrifera^ Holaster
placenta^ Serpula ilium^ Eschara ads, Heteropora pulchella,
Reticulipora obliqua, Rhynchonella limbata, Terebratula semi-
globosa, and Plicatula barroisi.

There are no zoological divisions in this zone, as the dominant
forms continue from top to bottom, and afford a notable and
continuous facies. Micraster is the true guide, and for details the
reader is referred to the paper on this genus, already quoted. We
find no Micraster with "smooth" or "sutured" ambulacra in
this zone, but they are all of the " strongly-inflated," or more
commonly, of the " sub-divided " type. This applies equally to
broad and narrow forms. The narrow forms greatly outnumber
the broad, and in this section the latter are never really common.

Echinocorys vulgaris var. ^bbus is very abundant, and is con-
fined to this zone and the zone below. There is singularly little
shape-variation of Echinocorys in this zone, and there are no sub-
varieties to record. The Echinocoridce are of a curiously uniform
size, and are never very large, as in the two zones immediately
above. It is worthy of note that a definite percentage of them
have thin tests. So that there should be no mists^e on this
point some of them have been worked out, and they are true
Echinocoridce, and not Holasters.

WHITE CHALK OF THE ENGLISH COAST. 309

The occurrence of a thin-tested Echinocorys appears to be
fairly common at the base of this zone, and in the H. planus zon^^
in all localities which we have worked ; but we find a small
percentage of tests with this peculiarity in all the zones which
yield this urchin. The variation in thickness of the test, there-
fore, would seem to be much commoner than in Micraster^ which
is singularly constant in this particular. Save in the case of
Micraster cor-bouis and of its passage-forms, where the test is
invariably thin, it is very rare to find a Micraster with a thin test.
Micraster is so plastic and variable in its essential features that
one would have expected the reverse to be the case.

Holaster placenta* is of frequent occurrence, and as many as
three are often found in a yard of chalk. They reach a great
size, being often over 80 mm. in length, and owing to the thinness
of the test, are rarely obtained in a perfect state. The description
and figure of this urchin are well worth studying, as comparatively
few field-workers are conversant with this useful fossil. It is
worth mentioning that Holaster placenta and If. planus can
always be separated in the field, if the trouble is taken to remove
and clean them, and that not a few records of Holaster planus in
this zone are due to a lack of appreciation of the distinctions
between the two species. Holaster planus does occasionally pass
up into this zone, but it is rare With Micraster for a guide there
need be no difficulty in separating the zones of J/, cor-testudinarium
and H planus.

The spines of Cidaris serrifera are found in profusion, and
replace those of Cidaris sceptrijera and C clavigera^ which are so
common in the tw6 zones above. This remark applies to the
Dover section only.

Serpula ilium^ though it occurs in the zones above, is never
common until we reach this zone. At this level and below, it is
always of small size, and is probably the commonest fossil.

Eschara ads is abundant both in this zone and the zone
below. Eschara lamatcki is the dominant Eschara of the
Chalk, but now, for the first time, another form successfully dis-
places it.

Reticulipora obliqua is very common and occurs in masses.
Here again it, for the first time, becomes a really common
form.

Heteropora pulchella occurs in colonies, often as large as a
brick, and is mostly confined to the lower half of the zone. It is
here a very characteristic fossil.

Vinadaria disparilis, so common in the upper zones, is
among the rarest of fossils here, and its absence is very
characteristic, for it is rarely found below this level.

Terebratula semiglobosa is common, but does not reach the
abundance and large size so common in the zone of H. planus,

• Cotteau, •• Ecb. de I'Vonne," p. 486, pi. 82, fig. 3.

February, 1900.] 23

lO DR. ARTHUR ROWE ON THE ZONES OF THE

In the latter zone also Terebratula carnea is very abundant and
characteristic, and its comparative absence in this zone is a good
diagnostic point.

Rhynchonella limbata is a common fossil at the top of this
zone at Dover, but it is limited to that situation, and, in the
writer's experience, its marked occurrence at this level is confined
to the section in question.

Plicatula barroisiy though found in the zones of Micraster cor-
anguinum and Marsupites testudinarius^ is a comparatively rare
fossil, and it is not until we reach this zone that it comes in
abundantly. Its white colour against the grey marl makes it a
conspicuous object.

Zone of Holaster planus.

FROM 200 YARDS NORTH-EAST OF THE LOW LIGHT TO A
PERPETUAL SPRING ISSUING FROM THE BASE OF THE
CLIFF, NORTH-EAST OF THE WINDLASS IN BANTAM

HOLE.

The spring is 150 yards east, on the 6-inch map, from the
north-east corner of Fan Hole. This additional measurement is
given because Fan Hole, by reason of the great scoop-out at the
top of the cliff, can always be located from the shore. The wind-
lass is in a trench, cut from top to bottom of the cliff, and is
used by the Coastguards for hauling up material.

This zone is also composed of nodular-chalk, full of organic
remains, and very similar in appearance to the zone above it.
There are no marly bands, and the flints are frequently spongi-
form. The upper limit of this zone has been given at the lower
of two strong flint-lines, 15 ft. apart, with a band of scattered
flints between them. The measurements of the zone are as
follows :

From the lower of the two strong flint-lines to the top of

the Chalk-Rock 16 ft.

From the top of the Chalk-Rock to its base . . 9 ft.

From the base of the Chalk-Rock to an open marl-band

between two pairs of nodular flint-lines . . 9J ft.

Total 34J ft.

The Chalk-Rock itself rises a few yards north-east of the
submarine telegraph-cable, between the High and Low Light.
This bed has been called Chalk- Rock because of its peculiar
lithological character. It is, usually, an intensely hard, cream-
coloured limestone. Associated with, and confined to this bed, is
often a peculiar gasteropod and cephalopod fauna. Mr. Henry
Woods* has written an admirable monograph on the moUusca of

• H. Woods, "The Mollusca of the Chalk-Rock," Quart. Joum. Ceol. See ., vol. Hi
and liii, February, 1896, and May, 1897.

WHITE CHALK OF THE ENGLISH COAST. 3II

this bed, and the reader is advised to consult it. Lithologically,
however, we have here no true Chalk-Rock, but only a thicker
nodular bed, or series of nodular beds, with patches of soft, grey,
marly chalk included in it. Green glauconitic grains, and green
phosphatic nodules are hardly ever seen, but brown nodules of
phosphatic chalk are present in abundance, and are much more
frequent than in the zone above. Many of the fossils are met
with in the form of brown phosphatic casts. Sponges are very
abundant.

It is a matter of opinion whether it is better to take the
H. planus-uont as low down as the open marl-band between the two
pairs of flint-lines, or to the top of the two first flint-lines, above
the open marl-band ; but the writer has been guided by purely
zoological evidence, and for that reason takes the lower level.
Between the base of the Chalk- Rock and the open marl-
band (that between the two pairs of flint -lines), we find
an abundance of Cyphosoma radiatum and Holaster planus
is common. Micrasttr and Echinocorys are much less
abundant than in the Chalk- Rock, but they begin here. It
is the occurrence of these typical urchins of the H. planus-
zone, together with Holaster planus itself, which has de-
termined us to ^\ the division-line at this point. As for the
upper limit of the zone, if collecting means anything, it clearly
shows that there is no lithological division between this zone
and the one above it. At this upper limit the evidence of
Micraster is so conclusive that the writer has never had the least
difficulty in obtaining a division-line between this zone and the
one above it, and the evidence obtained by this one fossil
invariably coincides with the disappearance of Holaster planus^
Micraster cor-bovis, and J/, leskti. There is a curious diminution
in the number of Micraster^ and even of Echinocorys^ in the space
of chalk (about 15 ft), which forms the transition area between
the two zones in question.

. We have just over half-a-mile of this zone, all in good condition
for collecting, and it is the finest section of the zone with which
the writer is acquainted. The gentle dip of the beds permits
every foot of it to be worked in succession.

Typical Fossils of the Zone of Holaster planus.

Holaster planus \

Micraster pracursor \ of the group form peculiar |

Micraster cor-testudinarium ) to this zone

Micraster cor-bovis 34 J ft.

Micraster leskei ........

Echinocorys vulgaris var. \^ibbus . . . . .1

Gasteropods and Cephalopcds (when present) . '

312 DR. ARTHUR ROWE ON THE ZONES OF THE

Other characteristic fossils are Ptntacrinus^ CardiasUr anan-
chytis^ Cidaris serrifera, Cyphosoma radiaium^ Holaster placentay
Serpula ilium^ Eschara acis^ Rhynchonella cuviert\ K. plicatilis^
Crania egnabergensis var. striata, Terebratula carnea, T, semi-
globosay Terebratulina gracilis^ Piicatula barroisi, and Inocera-
mus sp.

There are no zoological divisions in this zone, save where the
Chalk-Rock occurs. This bed may exist both zoologically and
lithologically ; zoologically alone, or lithologically alone ; or may
be absent in both senses. All these variations have come within
the writer's experience. In English sections there is no warrant
for the use of a separate Micraster Ieskei-zov\e,

In this section the Chalk-Rock only exists in the zoological
sense, and the peculiar fauna is very rich. If we trace up the
dominant fauna of this zone from its base to the bottom of the
Chalk-Rock, through the Chalk-Rock, and above it to the
junction with the zone above, we find no alteration in the fossils
whatever. Holaster, Micraster, and Echinocorys pass through the
Chalk-Rock unchanged, and even a very plastic form like
Micraster pursues its evolution without any deviation. The writer
acknowledges the usefulness of a hard, rocky bed in local survey-
ing, but otherwise he regards it as a mere interpolation, in no
way affecting the life-history of the zone, either by its presence
or absence. Too much importance has been given to this very
variable and inconstant bed, and to make it a base-line of the so-
called Upper Chalk seems to be particularly lacking in point, as
in not a few sections it does not exist at all.

Holaster planus. — A comparison between this well-known
species and the less-known Holaster placenta has been made on
page 309. It never reaches the large size of Holaster placenta
and differs from it in being taller, in having a well-marked anteal
sulcus, and a rounded base. Holaster placenta, on the other
hand, has little or no anteal sulcus, and has a perfectly fiat base,
with a sharp-edged ambitus, such as we see in Holaster trecensis.
The downward range of Holaster planus, as far as we have yet
traced it, is to the top of the R. cuvieri-zont ; but it becomes a
rare fossil as soon as we pass below the middle- third of the
T, gracilis-zont.

Holaster placenta is not so abundant in this zone as in that
immediately above, but it is a common fossil. Hubert's con-
tention that it is a guide-fossil to the zone of M. cortestudinarium
alone may be true in France ; but in England the writer has a
range for it from the top of the zone of Rhynchonella cuvieri to
the base of the zone of Actinocamax quadratus, the highest
and lowest occurrences being of course rare. It is much
smaller in the higher and lower zones, and its maximum
development, both m size and abundance, is in the zone of
M, cor- testudinarium .

WHITE CHALK OF THE ENGLISH COAST. 313

Micraster cor-bcvis is found in both a small and a large form,
and varies in length from 50 to 80 mm. It is not common, and
broken sections of it in the cliff face are generally mistaken for
Hoiasier, The only thing is to pick the fossil out and clean it, as
a determination can then be made even from a small portion of
the test. The largest examples have been found above the
Chalk-Rock. Micraster Uskti is even a better guide-fossil than
Micraster cor-lnn'is, as at Dover its range is practically restricted to
the limits of this zone. For the range and description of
Micraster cor-bovis and M, leskei the reader is referred to the
paper on Micraster.

Echinocorys vulgaris var. gibbus is very abundant, and in no
way differs from that in the zone above.

Pentacrinus is a fine zonal-guide in every section in this zone
in the South of England, as it occurs in abundance, and weathers
out well It is rare in the zone above, and is fairly common in
the upper-part of the 7! gracilis-h^^s^ but its maximum develop-
ment occurs in this zone.

Cidaris serrifera is still the dominant form in this zone, as in
the zone above.

Cyphosoma radiatum reaches its maximum development in this
zone, not only in this section, but in all others on the South Coast.
It is particularly common at the base, and also in the first 20 ft.
of the zone of Terebratulina gracilis. Its downward range is to
the base of the T. graciliszoixG, and it ranges upward as high as
the Belemnitella mucronatazoixe, becoming rarer as we ascend
in the zones.

Cardiaster anamhytis is never a common fossil, but is very
suggestive of the zone, as only one example has been found in the
zone of M. cor-testudinarium. It is not confined to the Chalk-
Rock.

Scrpula ilium is as common here as in the zone above, and
the chalk is crowded with them.

Eschara acts is very abundant, and can be picked out of the
soft marly pockets in this zone by the score. There are many
other forms of Bryozoa found here, but none of them are suflS-
ciently characteristic to record.

Terebratulina gracilis is of frequent occurrence in this zone,
but it rarely extends into that immediately above ; and the same
remark applies to Rhyruhonella atvieri.

Terebratula carnea and T, semiglobosa are found in unexampled
profusion in this zone, especially immediately above the Chalk-
Rock, where the largest examples are found. The Terebratula
carnea is not the true form of the Belemnitella niucronata-htds at
Meudon, but is much broader, and with a larger foramen.
Wherever we have worked this zone, there have we found this
broad form in a profusion which makes it one of the most easily
recognised guide-fossils.

314 I^R- ARTHUR ROWE ON THE ZONES OF THE

Rhynchonella piicatiiis is also abundant at the same level, and
reaches a large size. The var. octoplicata is the commoner form.

Crania egnabergensis var. striata may almost be called a
common fossil in this zone, in the South of England, and it has
an unbroken range from the zone of T, gracilis to that of A,
quadratus ; being, however, only really common again in the last-
named zone.

Inoctramus brongniarti is found in this zone at Dover, and
extends to the zones immediately above and below it, but in
reduced numbers. It is commoner here than in Sussex.
Inoctramus sp. : This is figured in Mr. Woods' paper (pi. xx\ii,
figs. 14 and 15), and is abundant at Dover in this zone. It
occurs occasionally in the zone above and the zone below, but it
is only abundant in the H, planus-zont. It is not confined to the
Dover section.

Plicatula barroisi is very abundant in this zone and the one
above, and we have never met with it so abundantly as at Dover^
where fifty examples could easily be found in a day's collecting.
This fossil is not well-known, and the reader is referred to Mr.
Henry Woods'* paper on the Chalk-Rock for an accessible
figure. We have found it from the base of the T. graciiis-zonQ to
the top of the Marsupites-zom^,

Pleurotomaria perspecliva and Turbo ge?fimatus are the two
gasteropods upon which we can rely, even when the Chalk-Rock
fauna is not represented. The former has been found in every
section of this zone which the writer has worked, though it is
never an abundant form. A Pleurotomaria^ apparently of the
same species, ranges from the zone of R, cuvieri to that of
A, quadratus^ but it is always rare.

It has been suggested that the zones of H, planus and J/, cor-
testudiuarium should be merged into one, on the ground that they
cannot be separated in the field in inland sections. We can only
say that we have yet to find a section in either zone which cannot
be readily assigned to its proper horizon, and that on purely zoo-
logical data. This does not apply to cliff-sections only, but to ill-
exposed inland sections. We are quite aware that Holaster planus
is uneven in its distribution within its own zone, and cannot be relied
upon to be present in quantity. One magnificently air-weathered
bluff in South Dorset gave an illustration of this, as not a single
Holaster planus could be found : so we relied upon Micraster, Tere-
bratulacarnea, and Pentacrinusior our determination, and obtained it
with ease. Close by was another bluff, which was full oi Holaster
planus^ as well as the other guide-fossils. Micraiter is always
sufficiently common to be a ready means of determination, and
it is infinitely more abundant in these two beds than in any
others. For our own part, we desire no easier or readier means
of determination.

• O^. cit.^ pi. xxvii, fi^s. 18 and 19.

WHITE CHALK OF THE ENGLISH COAST. 31$

Whether Holasttr planus is a suitable name-fossil for this zon.
has often been discussed, but we very much doubt if a better can
be found We know perfectly well that its range is not limited
to this zone any more than are the fossils which give their names
to the zones of R, cuvieri^ T, gracilis, M, cor-testudinarium or
M. coranguinum, restricted in their range to the zones mentioned.
We are never forced to rely upon one fossil for obtaining a zonal
determination, and we know that, linked with the name-fossil,
which here attains its maximum development, is a group of asso-
ciated forms, such as Micraster cor-bavis, M, kskeiy M, precursor
and M, cor-testudinarium (of the form peculiar to this zone), upon
which we can rely, if the name-fossil be not well represented. It
is this association of life-forms, and their variation, as we trace
them, zone by zone, which gives zonal geology its value. Neither
Micraster cor-bavis nor M, leskei is restricted to this zone, nor
can we rely upon the cephalopods and gasteropods, as they are
not always present. The only fossils which are alike abundant,
and definitely limited to this zone, are the groups of Micraster
precursor and M. cor-testudinarium, of the peculiar facies found
at this horizon. Good, however, as are these groups for zonal
determination, they are not a separate species, but only a zonal
variation of a far-extending group. Therefore they cannot be
used as a name-fossil, and we can see no better course than to
adhere to the old title of Holaster planus as the name- fossil for
this zone.

Zone of Terebratulina gracilis.

FROM THE SPRING ISSUING AT THE BASE OF THE CLIFF

TO THE CASTLE JETTY. ALSO THE SECTION IN THE

CLIFFS WEST OF DOVER.

At the time of writing, the Dover Harbour extension works
are in progress, and soon there will be no cliffs to collect from
south-west of Langdon Stairs. From a geological point of view
this is a pity, as there is no continuous section in this zone of
such extent and in such good order for working. These beds
consist of a hard, dead-white chalk, not very rich in fossils, with
numerous marly veins and seams; hard, white, nodular chalk
bands, and some irregular lines of flint. The chalk looks much
softer than it is, for it is hard to cut with a chisel, and fossils from
it are difficult to clean, owing to the adherent nature of the marl.
The marl-bands are a characteristic feature of this chalk in all
the South of England sections. The flints are black and compact,
with a thin white cortex.

The beds in this zone, as divided by marl-bands, have no
zoological value, the fauna being the same throughout. The

3l6 DR. ARTHUR ROWE ON THE ZONES OF THE

marl-bands are useful, however, in tracing the rise of the beds
towards Dover. They are as follows :

From first open marl-band, between two pairs of flint-
lines, to second marl-band 1 6 ft.

From second open marl-band to the third . . . 15 ft.

From third open marl-band to the fourth (the 4-ft.-band) . 4 ft.

From the fourth open marl-band to shore at Castle Jetty 56 ft.

This gives a thickness for this zone as exposed in the East
Cliffs, of 91 ft. The measurement has been checked by Captain
Gordon McDakin with an aneroid, at the tunnel leading from
Dover to the East Cliffs, and found to be correct.

On the west side of Dover this zone can be well studied in
the zig-zags at the Channel-Tunnel works, and at Lydden Spout,
and from fallen blocks on the shore. The dip of the beds is
much the same as in the East Cliffs. It is impossible to join-on
the sections in the two cliffs, as we have no lithological guide
which we can carry from one side to the other. The 4- ft. -band
rises in Langdon Bay and reaches the level of the Dover end of
the East Cliff Tunnel. It is seen on the low bluff at the west
end of Castle Cliff, and it can be traced into the bluff under the
Drop Redoubt. There we lose it, and no trace of it can be found
in Shakespeare's Cliff.

Some of this zone is, therefore, missing.

In the West Cliffs we have . . . .70 ft.
In the Fast Cliffs we have . . . .91ft.

Total , . . .161 (as exposed)

Typical Fossils of the Zone of Terebratulina gracilis.

Terebratulina gracilis ")
Micraster cor-bavis )■ 161 ft.

Inoceramus labiatus J

Other characteristic fossils are PentacrinuSy Discoidea dixoni^
Holaster planus y H. placenta^ Hemiasler viinimiis^ and Rhynchonella
cuvieri.

This zone cannot well be subdivided, as the three dominant
forms are found from bottom to top of the zone.

Terebratulina gracilis reaches its maximum development in
this bed, but it ranges from the zone of J^. cuvieri to that of
M. cortestudinarium,

Micraster cor-b(wis is by no means rare in this zone at Dover,
especially at the upper limit. Since the paper on Micraster was
written. General Cock burn has found two examples of the smaller
form of this urchin in the base of this zone in the West Cliffs. This
gives a new record for the section. General Cockburn possesses
the finest collection of this interesting urchin in existence.

WHITE CHALK OF THE ENGLISH COAST. 317

Sponges are found in profusion in this bed, and Gucttardia
stellata and Cratiatiaria fittoni reach a size and importance un-
known in any other zone, or in any other section of this zone.
We have measured a Gucttardia 14 inches across, and have a
mass of Craticularia a foot square. Ventriculites^ Cephalites^ and
F/ocoscyphia are equally abundant, and not infrequently we find
the last-named with its outer wall intact. We know of no section
so rich in Cephalites as this.

Pentacrinus is common at the top of this zone, but the large
size of the ossicles is lost when we approach the base of the zone.

The range of Holaster planus and H. placenta have already
been given on pp. 309 and 312.

Discoidea dixoni is by no means confined to the zone of R.
cuvieriy but may be found from base to top of the zone of T,
gracilis^ though it is not very common, save in certain localities. It
is sometimes found in the H. planus-zone.

Hemiaster minimus^ though not so common as in the zone
below, is well represented, and ranges up as high as the 3/. cor-
testudinariumzon^. At Beer Head, Devonshire, it is quite a
common fossil in the T. gracilis-beds, and runs to a laiger size
than anywhere else.

Rhynchonella cuvieri is a common fossil in this zone every-
where, and in some localities is quite as abundant as in its own
zone.

Inoceramus cuvieri is very abundant, and reaches a great size.
The writer found one example 3 ft. across, and removed the
hinge, which is as thick as one's wrist.

West Cliffs, Dover.

Zone of Rhynchonella cuvieri.

This bed can be studied in the zig-zags, and rich collecting
may be obtained from the fallen blocks on the shore. It is a
hard, dead-white chalk, veined with marl, and interspersed with
hard nodular bands of chalk. At the base is the " grit-bed,"
32 ft. thick, intensely hard and ringing to the hammer ; it is
rough with fragments of shells, chiefly Inoceramus labiatus.

The hard " grit-bed " is very prominent in the cliffs, based as
it is by the soft Actinocamax plenus-msixh^ which fall away from it,
leaving the sharp^overhanging edge of the " grit band." By this
means the bed can be traced in the cliffs to Folkestone.

The top of this zone may be fixed by a flint-line 70 ft. above
the base of the grit-bed, when the hard chalk passes into the
more marly, and comparatively softer, chalk of the zone above.
This division is, however, purely arbitrary, and only used for
convenience, and the zoological break is as imperceptible as the
lithological.

3i8

DR. ARTHUR ROWE ON THE ZONES OF THE

The Broad Zoological Divisions of the Zone of
Rhvnchonella cuvieri,

Rhynchonella cuvieri \

Inoceramus labiatus - throughout the zone

Discoidea dixoni J

Cardiaster pygmceus ]

Echinoconus subrotundus \

Echinaconus castama

Saienia granulosa \ \t

Glyphocyphus radiatus \

Cidaris hirudo |

Ammonites per amp his J

- 70 ft.

in the grit-bed = 32 ft.

Rhynchonella cuvieri is at its maximum development in this
zone. It ranges upward to the M, cortestudinarium-zon^^ where
it is rare.

Inoceramus labiatus has the same range, becoming rarer also
as it gets higher \ but it is always fairly common. Inoceramus
aivieri is as rare as Inoceramus labiatus is common, and is, there-
fore, useful in separating these two zones.

Discoidea dixoni is very common in the grit-bed, and passes
up, with varying frequency, to the lop of the Terebratulina gracilis-
beds. Occasional specimens are found as high as the zone of
Holaster planus. It is notably common in the T, graa'lis-beds at
Beer Head, Devonshire. General Cockburn has found several
specimens with the anal plates in situ.

Cardiaster pygmccus is very common in the " grit-bed " at
Dover. It rapidly decreases in frequency as we ascend the zone
and is a rare fossil in the zone of T, gracilis except at Beer Head.
We have never met it at a higher level, save in one very large
example from the base of the M. cortestudinarium zov\^ at Dover.
Dr. Gregory referred the solitary specimen to this species.

Echinoconus subrotundus and E. castanea are found
abundantly in the upper part of the " grit- bed," and scattered
examples of the former are found throughout the zone, and even
in the T, gracilis-heds. Echinoconus castanea has a more restricted
range, and is rare beyond the " grit-bed." At Dover a very small
form of this is common, but we have not met with it elsewhere.

Saienia granulosa ranges as high as the zone of Actinocamax
quadratus, but its maximum development is in the " grit-bed."
The only other zone where it occurs with a similar frequency is in
that of Holaster planus. It is comparatively rare in the zones of
Micraster cor-testudinarium and Marsupites testudinarius, but it
again comes in rather strongly in the zone of A. guadratus,

Glyphocyphus radiatus is always a rare fossil, but we have
invariably found it in the lower part of the zone in the sections
which we have worked. Its range appears to be much restricted,
and it is thus a useful zonal guide.

WHITE CHALK OF THE ENGLISH COAST. 319

Cidaris hirudo does not occur with us in the same abundance
as it does in France in the zone of 7! j^adlis. Here it ranges
from the zone of Rhynchonella cuvieri to that of Bekmnitella
mucronata. It is a common form at Dover, Beachy Head, and
Beer Head, especially in the last locality, and is more frequently
found in the zone of R. cuvieri than in that of 7! gracilis.

RadioliUs mortoni is not uncommon in this zone at Dover, and
it extends down as for as the Chalk-Marl. We have not met with
it in the zone of T. gradHs, nor did we lind it in the R. n/Tifri-ionc
at Beachy Head. The only other occurrence of RadioUtes which
we have to mention is, curiously enough, a soUtary example in the
MarsupiteS'ZOikt at Margate.

Terebratula semiglobosa is a useful guide-fossil in this zone.
In the true type of Terebratula semiglobosa the frontal margin is
undulated ; but in the forms found in this zone, and to a less
extent in that of Terebratulina gracilis, it is straight. By this we
do not mean that both frontal and lateral margins are straight, as
in Terebratula camea, but that the central biplication is absent
The shell is also much narrower and very tumid. This is the form
which we understand as Terebratula semiglobosa var. albensis. We
know of no other zone where this shape occtu^ with such frequency.

WTiether the zones of R, cuvieri and T gracilis should be
merged in one is a moot point. From a purely zoological point
of view we are of opinion that it is better to separate them,
partly because there is a certain difference in the fauna of the two
zones, and partly from force of custom. Still there is less need
for separation here than in any two other consecutive zones. If
they were merged, Barrois' title of Inoceramus labiatus would do
as well as any, as the shell occurs in great abundance, and is
constant throughout the two zones. If they are to be separated
it is probable that Rhynchonelh atvieri is the best name-fossil for
the lower zone, as it can be removed so much more readily for
determination than can Inoceramus, and it is so much better
preserved. The disadvantage of Terebratulina gracilis as a name-
fossil is that, in wave-worn sections, it is very hard to find, as it is
destroyed at once. In air- weathered sections, on the other hand,
it is an excellent guide, as it is very abundant, and shows up well.
In any case the zone of T gracilis is a very colourless one.

An ideal arrangement would be to have an echinoid as the
name-fossil for both zones, or to have a separate urchin for each
zone. Let us see how it works out for the R. cuvieri-zone. For
Dover and Beer Head Cardiaster pygmaus vfO\i\d do well, because
it is so abundant ; but it would be useless for Dorset and Beachy
Head, as it is so rare there. In the same way Discoidea dixoni
would do for Dorset, I>over, and Beer Head, but not for Beachy
Head.

In the case of the T graci Its-zone, Discoidea dixoni would do
fairly well all round, but it seems absurd to give it as a name-fossil

320

DR. ARTHUR ROWE ON THE ZONES OF THE

when its maximum development is in the zone below. Micraster
cor-bovis, again, though it is fairly abundant at Dover and Beer
Head, is too rare in Dorset and at Beachy Head to be a useful name-
fossil. Besides, the test is so thin that complete specimens are rare,
and it is not everyone who would have the knowledge to deter-
mine the form from fragments. On the whole we prefer the
division and title of the zones as herein given.

Before leaving the Dover section it will be well to give the
beds in succession, from the zone of T, ^acilis to that of M. cor-
anguinum^ as seen from below upwards, in the zig-zag at Langdon
Stairs.

Section in Langdon Stairs.

Below the lowest slope there are rough steps cut in the cliff,
which are in the zone of T. gracilis^ with the second open marl-
band showing.

\5t slope, — At the bottom of this slope is seen the first open marl-
band, with the two pairs of flint bands above and below it,
marking the junction of the T. gracilis- and H, planus-zonts.
The rest of the slope is in the zone of H, planus^ and at the
top of the slope, in the corner where it joins the second
slope, is the junction of the zones of H, planus and
Micr aster cor-testudinariu m .
2nd slope. — All of this is in the zone of M, cor-testudinarium.
yd slope. — All of this is in the zone of M, cor-testudinarium^ and
the thin M. cor-testudinariu m-\.2h\:\'2iX occurs in the lower part
of the slope.
4/// slope. — All this is in the zone of M. cor-tvstudinarium,
^th slope. — Shows the junction of the zones of M. cor-testudinarium
and M. cor-anguinum \ the basal M. cor-anguinum-taihu\aLr is
one-fourth of the way down from the top of the slope.
6M slope. — All of this is in the zone of -)/. cor-iinguinum. The
measurements taken of the beds on the shore were checked
here, and agreed in all instances.

Measurements of the Zones in the Kent Coast.

The approximate measurements of the zones in the White
Chalk of the coast of Kent are as follows :

ft.
Zone of Jfarsupites testudinarius . 1 1 6 (as exposed)
Micraster coranguinum . 2 So
Micraster cor testudinarium 56
Holaster planus . . 34 i

Terebratulina gracilis . 1 6 1 (as exposed)

Rhynchonella cuvieri . . 70

Total

7i7i

WHITE CHALK OF THE ENGLISH COAST. 321

PART II

COAST OF SUSSEX.
D. Eastbourne to the Cuckmere.

Barrois' admirable work is the only one to consult on this
coast. The section is not an easy one to read, and a day would
be well spent in walking from Eastbourne to Birling Oap, so as to
get a comprehensive idea of the beds before collecting. A good
spring is found on the reefs a little east of Belle Tout, and another
under it.

We see no more coast-sections in the Chalk, after we pass
Folkestone, until we reach Eastbourne. The Cirey Chalk can be
reached from the west end of the Parade, and time will not be
wasted by walking along the shore to Beachy Head, as a mag-
nificent section of Actinocamax plenuS'm^x\% is exposed, based by
the zone of Holaster subglobosm^ and capped by that of Rhyn-
ihonella cuvieri. One passes all the beds in succession down to
the Upper Cireensand. Before doing this it would be well to
examine the old quarry called Holywell, where there is a pumping-
station to catch the water thrown out by the A. plenus-tndiTh.

In Holywell we have a fine section of Rhynchonella cuvieri
and Terebratuiina gracilis-uoTits, and we have a chance, by taking
in the cliffs west of the main quarry, of obtaining a complete
thickness of the former zone, which here measures loo ft. A
quicker way to reach Beachy Head is to walk along the cliffs to
Cow Gap, which is merely a narrow cliff-path to the shore, and
then to descend to the beach, which lands us within 1,200 yards
of the main section. It should be remembered that, after we
pass Cow Gap, there is no way up from the shore until we reach
Birling Gap — a distance of 3^ miles, and very heavy walking all
the way.

By descending to the shore at Cow Gap a complete exposure
of Chloritic Marl, and the reefs in the Upper Greensand may
be seen. In the cliffs north of *' Falling Sands "we have a good
section in Chalk Marl, //. sub^^ioboiui-ziiwe. and A. plenusm2s\^
capped by the zone of R. cuvieri. There may l>e s<^>me of the
T, graciiis-20T\Q at the top, but the falls only give evidence of a
Rhynchonella cuvieri fauna.

The reefs west of •* Falling Sands " show, in proper succession,
Rhynchonella cuvieri and //. subj^Mosuizonts^ Chalk Marl,
Chloritic Marl, and Upper Greensand.

This brings us to a point on the shore corresponding to the
Watch House on the top of the cliff, which is the east tml of a

322 DR. ARTHUR ROWE ON THE ZONES OF THE

large and ancient turf-clad fall, known locally as " Gun Gardens,"
from the fact that it was once cultivated, and that a small battery
was there. Gun Gardens is east of "The Charleses," on the
6-inch map, which is a local name for semi-detached pinnacles at
the top of the cliff in M, cor-an^inum-cha\k. At the east
corner of Gun Gardens, under the Watch House, we have a fine
section from the zone of Holaster subglobosus to that of Micraster
cortestudinarium \ and at the west corner of Gun Gardens is
another fine sheer surface, which shows the series from the zone of
Rhytichonella cuvieri to the base of the M, cor-anguinum-zoxi^^ with
the thick M, cor-anguinum flint tabular passing out at the top of
the cliff.

In Gun Gardens itself, half-way up the slope, wc see a white
chalk bluff (marked on the 6-inch map), the lower part being in
the R, cuvieri-zont, and the summit in that of T, gracilis, the two
zones being roughly divided by a marl-band. This bluff is easily
accessible, and is well worth the climb, as it is the only well-
weathered surface in the R. cuvieri-zone at Beachy Head. It
may be mentioned that Gun Gardens is thejplace where people
climb down from the top of the cliff, and where many lives have
been lost in the attempt.

At the west angle of Gun Gardens we see the actual junction
of the zones of R. cuvieri and T. gracilis^ marked by the lowest
marl-band. This is not on the shore-line, but on the grass slope.
The actual junction on the shoreline is seen 293 yards west of the
west corner of Gun Gardens, and is marked by the marl-band
already mentioned. The thickness is practically 100 ft., the
same as at Holywell. These beds are on the Beachy Head
anticline, and are dipping strongly to the west.

Passing west for 150 yards we come to a point on the shore
which is a little west of the figure " 364," on the 6-inch map, on
the path at the top of the cliff We here see the junction of the
zones of T. gracilis and H, planus^ and it is very easy to identify
this, on the shore-line, by the contact of the flintless T. gracilis
chalk, and the flinty H. //a/zz/j-chalk. This gives us a measure-
ment of 170 ft. for the zone of T. gracilis.

Going further west, we reach, at a spot a little east of the
letter / in Ford's Point, on the 6-inch map, the junction of
the zones of H. planus and M, cor-testudinariu?n. This is roughly
indicated in the cliff-face by a vertical fissure, extending from top
to bottom, and filled in with ferruginous material. Another way
to pick up the junction of the zones of H, planus and M. cor-
testudinarium is to measure 240 ft. west along the shore-line, from
where the top of the flintless T, gracilis-zont rises from
the sand. These are useful guides, but the only legitimate
way is to get the actual junction from zoological data, and
this can only be done by collecting foot by foot. Owing to
the zone of H, planus being on the sharp rise of the anticline,

WHITK CHALK OF THE ENGLISH COAST. 323

we get a very short section of it. The thickness of this zone is
48 ft.

From this point we walk westward for a mile, the dip of the
beds being now comparatively slight, until we come within
200 yards of Belle Tout, where we see the junction of the zones
of M. cor-tesiudinarium and M, cor-anguinum. The approximate
junction is fixed by a thin flint tabular band, which rises from the
sand at this point, about 60 ft. below the very thick tabular band,
which is obviously in the M, cor-angtiinum-zont.

The position of Belle Tout Light can be ascertained by
finding "Darby's Hole" at the bottom of the cliff. This is a
double cive in a vertical fissure ; the thick M. cor-anguinum
tabular band passes between the two caves, and a wire rripe
hangs down them. This cave is about 50 yards west of the flag-
staff, which can be seen at low water by walking out on the reef.
The Lighthouse itself is too far back to be seen.

Two worked caves (marked on the 6-inch map) are found be-
tween this cave and Birling Gap; and 100 yards west of the
second, and most westerly of these caves, is seen the strong
M. cor-angugftumiahu\siT rising from the shore, and passing 5 ft.
under the second cave.

This is the same strong tabular in the A£ cor-a»guiftt/w-zone,
which we noted before, as it passed out at the top of the cliff on
the west side of Gun (jardens. This strong tabular can be traced
on the reef some 200 yards east of Birling Gap. In 1898-9, it
formed a thick sheet on the top of the reefs, but is gradually
being broken up by the waves. Fifty feet above the thick
tabular in the cliff is seen another and much thinner tabular, and
15 ft above that, is a very indistinct yellow sponge band. It is
important to notice this, as Barrois lays great stress on it in the
" Seven Sisters " Section, and it will be referred to later on.

Zone of Rhynchonella cuvieri.

FROM THE EAST CORNER OF GUN GARDENS, WHERE THE
JUNCTION OF THE ZONES OF A, PLENUS AND R, CUVIERI
ARE SEEN, SOME 30FT. ABOVE THE SHORE LINE, TO A
POINT 293 YARDS WEST OF THE WEST CORNER OF GUN

GARDENS.

It is impossible to give a better guide than this, for there is
nothing on the shore-line, or the top of the cliff, to give a clearer
indication. The chalk is of the same nature as that at Dover,
save that the " grit-bed " is ill-developed. There are no flints,
and the iron-pyrites is the same as that seen in the Grey Chalk.
This is a ver>' poor section from the collector's point of view, as
the chalk is not nearly so rich as that at Dover, and, in addition.
It is so pounded by the shingle that all fossils are smashed off as
soon as they weather out.

328 DR. ARTHUR ROWE ON THE ZONES OF THE

This last-mentioned tabular flint-line will be called the M, cor-
testudtnarium-idi)ou\2iX, as it approximately marks the zoological
break between this zone and the one above it. No attempt is
made to correlate it with the M. cor-fesfudinarium-iabulsLT at
Dover, as the lithological conditions vary so much in the two
sections. This Af. cortestitdinarium-izbu\2iT is situated 200 yards
east of Belle Tout, at which point it rises from the beach, and
below it are seen three strongly-marked yellow nodular bands.
Below the M. cor-festudinarium-i2ib\i\3iX the typical fossils of this
zone come in with a rush, and though there are several yellow nodular
bands above it, the fossils are essentially those of a basal Micrasier
cor-anguinum fauna. This is a marked contrast to Dover, where
the lithological and zoological break coincides, and is only another
instance where lithology fails us, and where rigid zonal collecting
can alone help us out of the difficulty.

Typical Fossils of the Zone of Micraster cor-
testudinarium.

IdZlTestuZ^^^^^ ] of group-form peculiar to this zone
Echinocorys vulgaris var. gibbus

As at Dover, there are no zoological divisions in this zone, the
dominant forms being continuous throughout. Micrasier is our
only reliable guide, and the essential features of the test, which
were so helpful at Dover, are equally reliable and constant here.
The proportion of the broad Micraster cor-testudinarium forms is
rather larger than at Dover, and the percentage of occurrence
of the " sub-divided " ambulacral area is also larger than at
Dover, and is quite characteristic of this zone. Echinocorys
vulgaris var. gibbus is quite as common as at Dover, and the
unfailing abundance and uniformity of this fossil, in the zone, is
constant in all the sections which we have worked. Echiftoconus
conicus and Cyphosoma konigi were found here, but not at Dover.
They are rare fossils in this zone. The spines of Cidaris clavigera
are, if anything, in greater profusion than in the zone below, and
while Cidaris serrtfera is still a characteristic form, it is not so
abundant as the former.

Terebratula semiglobosa is not so common here as at Dover, save
at the base of the zone ; but in the same zone at Seaford Head it
is quite as common.

Rhynchonella limbata^ so common at the top of the zone at
Dover, is here represented by a solitary example. The same
small form of Lima hoperi is common to both sections. Holaster
placenta is common, but not so abundant as at Dover, and, as has
been remarked before, small examples of this fossil have been

WHITE CHALK OE THE EKGUSH COAST. 3^9

mistaken for Holaster planus^ and for a thin>tested JEUkimvons
which is found at this leveL The Bnozoa in the section are
abundant, and much resemble the Dover and the Chatham forms,
as Eschara ads, Recticulipora obliqya, Homtrosokn ramuhrsum^ and
Semicytis rugosa are all abundant. On the other hand,
Pavolunulites, Micropora intricata^ and Mulitka which are
common here, are rare at Dover ; while Hcteropora pukheUa^ so
common at Dover, is practically absent here. No gasteropods
have been found. Plicatula barrmsi is but poorly represented, as
compared with Dover. Sponges are poor in this zone at Beachy
Head, with the exception of a small form of Pharctrospongia
strahani^ which is very abundant, both in this zone and in
the base of the J/, cor-anguinumzon^^ and is equally abundant at
Seaford Head.

Zone of Micraster cor-anguinum.

FROM A POINT 200 YARDS HAST OF BKLLK TOUT TO
THE CCCKMHRE.

Directly we pass above the M, cor'tcstudinariNm-tahular^
we come into a chalk with several yellow nodular bands, not
so well-marked as those below the tabular, but still of the same
nature. Lithologically, they would appear to belong to the Af,
cor-testudinarium-zontj but zoologically they must be included in
the zone of M, cor-anguinum, as the fossils are scanty and belong
to the higher zone. Above these nodular bands the chalk is of
the typical Micraster cor-angiti7ium nature. The flints come in
at regular intervals. Barrois says that they are l)lack, with a
thick, zoned cortex. This is true in certain situations, but
under the Seven Sisters they frequently have a very thin white
cortex.

Passing westward from the junction of the zones of \f. cor-
testudinariuvi and M. cor-anguinum, we come to Hclle 'I'out,
50 yards west of which is the double vertical cave, with the wire
rope, called Darby's Hole. Intersecting this double cave is the
strong M. cor- anguinum- tabuhr, rising from the shore
100 yards west of the first of two worked caves, which arc seen
between this point and Birling Gap, both being marked on the
6-inch map. The thick tabular passes 5 ft. under the floor of this
cave. About 50 ft. above this strong tabular is another thinner
one, with a yellow sponge-bed 15 ft. above it, here very badly
indicated. This is the bed which must have induced Barrois to
put so much of the upper part of the cliffs into the Afarsupi/es-zone.
He gives only a thickness of 1 20 ft. for the zone of Micraster cor-
anguinum^ which would appear, on the face of it, to be an
inadequate estimate of this bed in the south of England. Barrois
evidently looked upon this tabular flint-line, with the f»ponge'l>ed

33© DR. ARTHUR ROWE ON THE ZONES OF THE

15 ft. above it, as analogous to the " Whitaker 3-inch" tabular
and the ** Barrois sponge-bed " in Thanet. These will, therefore,
be alluded to as the ** spurious tabular and sponge-bed," so as to
avoid confusion. Had this been a correct deduction, all the
chalk above this sponge-bed would have been in the AfarsupUes-
zone, and there would have been room for some of the Actinocamax
quadra tus-zov\e as well. We know, however, that in this section
the sponge-bed is only about 120 ft. above the top of the M, cor-
tesiudinarium-zov\^^ so we must see if there is any way to estimate
the normal thickness of the M, coranguitium-zont, and at the
same time to establish the existence of the Marsupiies-chzWi. The
only way to do this will be to collect along the whole exposure,
and to examine the top of the cliffs as well. In point of fact,
there are no bands in the section comparable to the ** Whiiaker
3-inch tabular," and the ** Barrois sponge-bed " of Thanet.

Fortunately, the fine section under the Seven Sisters gives us
the clue to the base of the Marsupifes-zonQy and Seaford Head
settles the whole succession of beds, for we get a complete
section there from the zone of Af. cor-testudinariufn to that of
Actinocamax quadraius.

It will be seen that this identification by Barrois of the
" spurious tabular and sponge-bed " with the same guide-beds in
Thanet, vitiates the whole of his section from Belle Tout to
Brighton.

On either side of Birling Gap we see the *' spurious tabular
and sponge-bed" half-way up the cliff, and here, as we pass
further westward, the sponge bed is very clear. These bands dip
to the west until, at Crowlink Coastguard Station, the flint-line is
level with the beach; but from that point the bands steadily rise again,
and very soon the sponge- bed dies out. In these lower cliffs we have
a better chance of studying the beds in the upper part of the
cliff, and we notice that, as at Beachy Head and Seaford Head,
the flint-lines space out in the upper third of the cliff. If we view
the "Sisters " from either side we notice that the tint of the chalk
in the highest " Sisters " is of a greyer colour, and that this
discoloration corresponds with the upper of two strong nodular
flint-lines, 9 ft. apart, and that these two flint-lines generally pass
out of the cliff in the hollows between the highest " Sisters."
The importance of this observation will be seen when we come to
trace the same two flint-lines in Seaford Head, for we find that
UintacHfius-chzWi is there apparently limited below by the upper
of these two flint-lines, 9 ft. apart.

It is clear that we have a chance of finding some portion of
the Marsupites -zont at the tops of the highest " Sisters." In 1898
we found at the summit of the first and fourth " Sisters " (counting
from the Cuckmere), Uititacriuus, the nipple-shaped head of
Bourqueticrinus and Echinocorys vulgaris var. pyramidaius. This
gave us our position at once. These fossils were obtained in little

WHITE CHALK OF THE ENGLISH COAST.

331

bare patches, where the turf had been denuded at the cliff edge.
But for these providential little weatherings we should never have
found these guide-fossils, as there was no fall of cliff from the top,
and the rolled blocks on the shore gave no indication of
MarsupiUS'Zont whatever, though they were searched for
evidence. In November, 1899, however, we found a fall under
the third " Sister," capped by turf. This contained Uintacrinus
in abundance, and we again found the same fossils as before at the
top of the cliff, together with Terebraiulina rowei and Serpuia
turbinella : and what was of even greater interest, on the first and
highest " Sister," Mr. C. W. Andrews, who was with us, found
two Marsupitfs plates. This does not of necessity mean that we
have any thickness of Marsupites-hsind^ but merely that the
Aiarsttpites-haind and the (/infacrinMs-hsind blend here.

There are only two places in the section, between Beachy
Head and Birling Gap, where there could possibly be a cap of
Afarsupifes-cYialk. One place is half a mile west of "the
Charleses," and the other at Belle Tout. We have made repeated
search in all fallen chalk from the cliff-top at these situations, but
no characteristic fossil has been found ; nor did examination of the
little turf-weatherings at the top of the cliff yield any better result.

There is a^way up at Crowlink Coastguard Station, which
in 189S was by no means easy, and in 1899 was inaccessible, except
by a ladder.

Typical Fossils of the Zone of Micraster
cor-anguinum.

MicrasUr cor-anguinum .

of form peculiar )

Echinocorys vulgaris

Echinoconus conicus
Epiaster gibbus
Micraster pmoirsor
M. cor-t€studinariiim
Inoceramus involutus

to this zone.

• of group form pe- \
) culiar to this zone. .-

upper
three-fourths.

lower fourth.

-242 ft.

For other characteristic fossils, and for the description of them,
see p. 301. A working knowledge of Micraster is doubly im-
portant here, as both at Beachy Head and at Seaford Head,
we can only fix the junction of this zone with that of M, cor-
testudinarium by this means. Inoceramus involutus is even rarer
here than at Dover. In the lower |>art of this zone, both at
Beachy Head and at Seaford Head, we find numerous examples of
a small form of Pharetrosfon\^ia strahani and of Multelea^ and
both these extend into the zone below. Otherwise there is
nothing in which this section differs from any other in the same
zone. Echinoci'uus conicus is rarer in this zone in Sussex than in
Kent.

33© DR. ARTHUR ROWE ON THE ZONES OF THE

15 ft. above it, as analogous to the " Whitaker 3-inch" tabular
and the " Barrois sponge-bed " in Thanet. These will, therefore,
be alluded to as the ** spurious tabular and sponge-bed," so as to
avoid confusion. Had this been a correct deduction, all the
chalk above this sponge-bed would have been in the Marsupites-
zone, and there would have been room for some of the Actinocamax
quadrat HS-7sOnt as well. We know, however, that in this section
the sponge-bed is only about 120 ft. above the top of the M, cor-
tesiudinariumzow^y so we must see if there is any way to estimate
the normal thickness of the M, coranguinum-zow^^ and at the
same time to establish the existence of the Marsupite5-c\idi\vi, The
only way to do this will be to collect along the whole exposure,
and to examine the top of the cliffs as well. In point of fact,
there are no bands in the section comparable to the ** Whitaker
3-inch tabular," and the ** Barrois sponge-bed " of Thanet.

Fortunately, the fine section under the Seven Sisters gives us
the clue .to the base of the Marsupiteszowt^ and Seaford Head
settles the whole succession of beds, for we get a complete
section there from the zone of AI. cor-tesiudinartum to that of
Actinocamax quadratics.

It will be seen that this identification by Barrois of the
"spurious tabular and sponge-bed " with the same guide-beds in
Thanet, vitiates the whole of his section from Belle Tout to
Brighton.

On either side of Birling Gap we see the ** spurious tabular
and sponge-bed" half-way up the cliff, and here, as we pass
further westward, the sponge bed is very clear. These bands dip
to the west until, at Crowlink Coastguard Station, the flint-line is
level with the beach ; but from that point the bands steadily rise again,
and very soon the sponge-bed dies out. In these lower cliffs we have
a better chance of studying the beds in the upper part of the
cliff, and we notice that, as at Beachy Head and Seaford Head,
the flint-lines space out in the upper third of the cliff. If we view
the "Sisters " from either side we notice that the lint of the chalk
in the highest " Sisters " is of a greyer colour, and that this
discoloration corresponds with the upper of two strong nodular
flint-lines, 9 ft. apart, and that these two flint-lines generally pass
out of the cliff in the hollows between the highest " Sisters."
The importance of this observation will be seen when we come to
trace the same two flint-lines in Seaford Head, for we find that
Uintacrtnus-ch^Wi is there apparently limited below by the upper
of these two flint-lines, 9 ft. apart.

It is clear that we have a chance of finding some portion of
the Mars24piteszont at the tops of the highest " Sisters." In 1898
we found at the summit of the first and fourth " Sisters " (counting
from the Cuckmere), Uiniacrinus^ the nipple-shaped head of
Bour^uciicrinus and Echinocorys vulgaris var. pyramidaius. This
gave us our position at once. These fossils were obtained in little

WHITE CHALK OF THE ENGLISH COAST. 33 1

bare patches, where the turf had been denuded at the cliff edge.
But for these providential little weatherings we should never have
found these guide-fossils, as there was no fall of cliff from the top,
and the rolled blocks on the shore gave no indication of
MarsupiUS'Zont, whatever, though they were searched for
evidence. In November, 1899, however, we found a fall under
the third " Sister," capped by turf. This contained Uintacrinus
in abundance, and we again found the same fossils as before at the
top of the cliff, together with Terebraiulina rowei and Serpula
turbinella ; and what was of even greater interest, on the first and
highest ** Sister," Mr. C. VV. Andrews, who was with us, found
two Marsupites plates. This does not of necessity mean that we
have any thickness of Marsupites-hsLtxd^ but merely that the
Jfarst/pi/es-bsLud and the (/intacrt/ius-hsind blend here.

There are only two places in the section, between Beachy
Head and Birling Gap, where there could possibly be a cap of
Marsupites<h2\\i, One place is half a mile west of " the
Charleses," and the other at Belle Tout. We have made repeated
search in all fallen chalk from the cliff-top at these situations, but
no characteristic fossil has been found ; nor did examination of the
little turf- weatherings at the top of the cliff yield any better result.

There is a^way up at Crowlink Coastguard Station, which
in 1898 was by no means easy, and in 1899 was inaccessible, except
by a ladder.

Typical Fossils of the Zone of Micraster
cor-anguinum.

Micraster cor-angiiinum .

j:, J . , . f of form peculiar /

Echinocorys vulmris - ^ ^u- ( upper

-^ ^ I to this zone. ^ ^, v ..u

r »• • ( three-fourths.

EchinocoJius conicus . \ ^ ft

Epiaster gibhus ^ ^24211.

Micraster prcecursor \ of group form pe- \

M, cortestudinarium ) culiar to this zone. - lower fourth.
Inoceramus involutus ]

For other characteristic fossils, and for the description of them,
see p. 301. A working knowledge of Micraster is doubly im-
portant here, as both at Beachy Head and at Seaford Head,
we can only fix the junction of this zone with that of M. cor-
testudinarium by this means. Inoceramus involutus is even rarer
here than at Dover. In the lower part of this zone, both at
Beachy Head and at Seaford Head, we find numerous examples of
a small form of Pharetrospongia strahani and of Multelea^ and
both these extend into the zone below. Otherwise there is
nothing in which this section differs from any other in the same
zone. Echinoconus conicus is rarer in this zone in Sussex than in
Kent.

33 2 DR. ARTHUR ROWE ON THE ZONES OF THE

E. The Cuckmere to Seaford Head.

On the western side of the Cuckmere are low cliffs of a dirty
yellow colour, but west of Hope Gap they rapidly rise, and form
a very fine section. From the Cuckmere, to an oblique fissure-
cave under the Casirum, the bulk of the cliff is in the M, cor-
testudinarium-zont^ a distance of i ^ miles in this one zone. The
oblique fissure-cave is an important feature, as it marks the actual
junction of the zones of M. cor-testudinarium and M, cor-angui-
num. At Beachy Head (200 yards east of Belle Tout) we are able
to take a tabular flint-bed as the division line, but it does not
exist here, and we choose in its place a closed marl-seam, which
rises from the shore on the eastern side of the fissure-cave. This
seam is constant throughout the section and is very easily traced,
as the chalk often falls away below it, leaving a sharply-cut over-
hanging ledge. The fissure itself extends half-way up the cliff,
and is iron-stained at the top, where it is intersected by the strong
M, cor-anguinum'tahulsiTf here 60 ft. above the beach, and is
equivalent to the strong tabular in the same position at Belle
Tout. This M. cor-testudinarium-chTiWi is deceptive in appear-
ance, as it does not weather out in hard rugged knobs as at
Dover and elsewhere, and passing along it in %, boat, it was
impossible to assign it to this zone from general appearances.
The lithological features differ greatly from those at Beachy
Head, and both the M. cor-t€studtnarium-XQhu\2LXy and the
" spurious tabular and sponge bed," are wanting. This is a good
example of lithological features failing one in a restricted area.
At Further Point the beds begin to show evidence of a strong dip
to the west, and, by the time that we reach Seaford Head, they
are inclined at an angle of about 10 deg.

Passing a little further west of the oblique fissure-cave, we
trace the dip of ihe strong M. cor'afrguinum-tsibular to the shore,
below the west side of the Castrum, Still passing westward we
reach the point where two strong nodular flint-lines sink to the
shore. These are clearly the same two flint-lines, 9 ft. apart,
which we saw intersecting the bases of the highest of the
" Sisters " ; so it is probable that we are nearing the junction
with the Marsupiies-c\\2\\i. The only thing to do is to fix our
division line by collecting. We accordingly begin at the upper of
these two flint-lines, 9 ft. apart, and work eastward. We find no
trace whatever of Uiniacrinus ; so we retrace our steps and start
from the same point and work westward.

At once we find Uiniacrinus, This gives us our junction
line, and so that others may be spared the labour which we had
in finding it, we give a measurement from the stone groyne at the
east end of Seaford Esplanade, to the upper of two strong flint-
lines, 9 ft. apart. We took a straight line along the beach, and
this gave us 760 ft., from one point to another. The thickness of

WHITE CHALK OF THE ENGLISH COAST. 333

the M, cor-anguinumzont from this point to the marl-seam at the
oblique fissure-cave was 242 ft. The next thing to do is to find
MarsupiUs itself. At this juncture, it may be well to say that we
went over this very area in the section most carefully in 1898, and
failed to find a single Uintacrinus or Afarsupites plate. This
was due to the fact that every fossil is smashed by the shingle as
soon as it weathers out. This time we determined to miss
nothing, so we removed every piece of calcite from the cliff face
and cleaned it. By this means we got all the evidence which we
required. For 28 ft. 9 in. above the upper of two strong flint-
lines, 9 ft. apart, we got Uintacrinus ; and for 48 ft. 9 in.
above the Uintacrinus - chalk we collected Afarsupites,
Then came a space of about 20 ft. in which we got no
Afarsupites and no Cardiaster pilluLi^ but in which the
Echinocorys vulgaris var. pyramidatus began to blend with the
var. gibbus, and where Rhynchonella plicatilis was common.
Wherever we have met with a junction between the two zones of
Afarsupites and Actinocamax quadratus we have found the same
hiatus between Afarsupites plates and Cardiaster pillula^ and the
blending of the associated guide-fossils. Cardiaster pillula invari-
ably extends to the extreme base of the Actinocamax quadratus-
zone, and we always fix the lower limit of this zone by its presence.
The actual junction of the zones of Afarsupites and A, quadratus
can here be fixed by an open marl-band, 31 ft. above another
open marl-band, and 470 ft. in a straight line along the beach
to the stone groyne before mentioned.

We can now fix with certainty the upper and lower limits of
our Afarsupites-zont, for we know that Afarsupites plates are not
found above the second marl-band, and that Uintacrinus is not
found below the upper of the two strong flint-lines, 9 ft. apart.
Further observations may increase the downward measurement of
the Uintacrinus-bandy but not its upper limit : for we got a close
contact between beds containing Uintacrinus and Afarsupites
plates. As far as we can trace them, the measurements work out
as follows :

Uintacrinus-bsind . . . . . 28 ft. 9 in.
Marsupites-band . . , . . 48 ft. 9 in.

Total Afarsupites-zone . 77 ft. 6 in.

Now let us leave the clifls and stand out as far as we can get
on the shore, and trace upward the two marl-bands, and the two
flint-bands, to the Castrum at the top of the cliff. We find that
the marl-bands run up to the west side of the Castrum, and then
pass out at the top of the cliff; but that the two flint-lines, 9 ft.
apart, pass further eastward. To follow these we must go cast-
ward also, and by walking out on the reefs, opposite the oblique
fissure-cave, we trace the two flint-lines as they pass out at the

33 2 DR- ARTHUR ROWE ON THE ZONES OF THE

E. The Cuckmere to Seaford Head.

On the western side of the Cuckmere are low cliffs of a dirty
yellow colour, but west of Hope Gap they rapidly rise, and form
a very fine section. From the Cuckmere, to an oblique fissure-
cave under the Casirum, the bulk of the cliff is in the M, cor-
testudinarium-zont, a distance of i ^ miles in this one zone. The
oblique fissure-cave is an important feature, as it marks the actual
junction of the zones of M, cor-testudinarium and M. cor-angut-
num. At Beachy Head (200 yards east of Belle Tout) we are able
to take a tabular flint-bed as the division line, but it does not
exist here, and we choose in its place a closed marl-seam, which
rises from the shore on the eastern side of the fissure-cave. This
seam is constant throughout the section and is very easily traced,
as the chalk often falls away below it, leaving a sharply-cut over-
hanging ledge. The fissure itself extends half-way up the cliff,
and is iron-stained at the top, where it is intersected by the strong
M, cor-anguinum-t3bu\3iTf here 60 ft. above the beach, and is
equivalent to the strong tabular in the same position at Belle
Tout. This M. cor-te5tudinanum-chi\k is deceptive in appear-
ance, as it does not weather out in hard rugged knobs as at
Dover and elsewhere, and passing along it in %, boat, it was
impossible to assign it to this zone from general appearances.
The lithological features differ greatly from those at Beachy
Head, and both the M. cor-testudinarium-X2h\x\2iT, and the
" spurious tabular and sponge bed," are wanting. This is a good
example of lithological features failing one in a restricted area.
At Further Point the beds begin to show evidence of a strong dip
to the west, and, by the time that we reach Seaford Head, they
are inclined at an angle of about 10 deg.

Passing a little further west of the oblique fissure-cave, we
trace the dip of ihe strong M. cor'artguifium-idihnXzx to the shore,
below the west side of the Castrum, Still passing westward we
reach the point where two strong nodular flint-lines sink to the
shore. These are clearly the same two flint-lines, 9 ft. apart,
which we saw intersecting the bases of the highest of the
" Sisters " ; so it is probable that we are nearing the junction
with the Marsupiies-Q\i2X\ii, The only thing to do is to ^x our
division line by collecting. We accordingly begin at the upper of
these two flint-lines, 9 ft. apart, and work eastward. We find no
trace whatever of Uintacrinus ; so we retrace our steps and start
from the same point and work westward.

At once we find Uintacrinus, This gives us our junction
line, and so that others may be spared the labour which we had
in finding it, we give a measurement from the stone groyne at the
east end of Seaford Esplanade, to the upper of two strong flint-
lines, 9 ft. apart. We took a straight line along the beach, and
this gave us 760 ft., from one point to another. The thickness of

WHITE CHALK OF THE ENGLISH COAST. 333

the M, cor-anguinum-zon^ from this point to the marl-seam at the
oblique fissure-cave was 242 ft. The next thing to do is to find
Marsupites itself. At this juncture, it may be well to say that we
went over this very area in the section most carefully in 1898, and
failed to find a single Uintacrinus or Marsupites plate. This
was due to the fact that every fossil is smashed by the shingle as
soon as it weathers out. This time we determined to miss
nothing, so we removed every piece of calcite from the cliff face
and cleaned it. By this means we got all the evidence which we
required. For 28 ft. 9 in. above the upper of two strong flint-
lines, 9 ft. apart, we got Uintacrinus ; and for 48 ft. 9 in.
above the Uintacrinus - chalk we collected Marsupites.
Then came a space of about 20 ft. in which we got no
Marsupites and no Cardiaster piiiuia, but in which the
Echinocorys vulgaris var. pyramidatus began to blend with the
var. gidbusy and where Rhynchonella plicatilis was common.
Wherever we have met with a junction between the two zones of
Marsupites and Actinocamax quadratus we have found the same
hiatus between Marsupites plates and Cardiaster pii/u/a, and the
blending of the associated guide-fossils. Cardiaster pillu I a invari-
ably extends to the extreme base of the Actinocamax quadratus-
zone, and we always fix the lower limit of this zone by its presence.
The actual junction of the zones of Marsupites and A. quadratus
can here be fixed by an open marl-band, 31 ft. above another
open marl- band, and 470 ft. in a straight line along the beach
to the stone groyne before mentioned.

We can now fix with certainty the upper and lower limits of
our MarsupiteS'Zonty for we know that Marsupites plates are not
found above the second marl-band, and that Uintacrinus is not
found below the upper of the two strong flint-lines, 9 ft. apart.
Further observations may increase the downward measurement of
the Uintacrinus-baind, but not its upper limit ; for we got a close
contact between beds containing Uintacrinus and Marsupites
plates. As far as we can trace them, the measurements work out
as follows :

Uintacrinus-band . . . . . 28 ft. 9 in.
Marsupites-hdLT\d 48 ft. 9 in.

Total Marsupites-zon^ . 77 ft. 6 in.

Now let us leave the cliffs and stand out as far as we can get
on the shore, and trace upward the two marl-bands, and the two
flint-bands, to the Castrum at the top of the cliff. We find that
the marl-bands run up to the west side of the Castrum^ and then
pass out at the top of the cliff ; but that the two flint-lines, 9 ft.
apart, pass further eastward. To follow these we must go east-
ward also, and by walking out on the reefs, opposite the oblique
fissure-cave, we trace the two flint-lines as they pass out at the

33^

DR. ARTHUR ROWE ON THE ZONES OF THE

zone, when not damaged by the shingle, but the parts which are
in good order for working are limited.

There is no M. cor'testudinarium'iibu\2Jj as at Beachy Head
(Belle Tout), but much in the same position we find a thin closed
marl-band, which approximately marks the junction between this
zone and that of M, cor-anguinum. The reader is referred
to p. 327, where the same zone at Beachy Head is discussed.
This section in no way differs from the other, save that it does
not look like M, cor-tesiudinarium-chdiWi, and that several litho-
logical details which are present in one place are absent in the
other. There is no need to recapitulate the zoological details,
as they are the same in both sections. About 80 ft. of this chalk
is exposed, and we have worked the lowest part of it thoroughly,
and find no trace oi Holasier pianus-zon^ fauna. Micra s /cr shovrs
no evidence of nearing that zone.

At this point it will be convenient to put in condensed form
the lithological guides to the various zones at Seaford Head and
their measurements.

Measurements at Seaford Head.

Zone of Micraster
cor-Ustudinarium.

Zone of Micraster
cor-anguinum.

Zone of Marsupites.

Zone of Actinocamax \
quadratus. "|

From lowest part of M. cor-ifsiudinariuni-
zone to the oblique fissure-cuve,
where the closed marl-band divides
this zone from that of M. cor-angui-
num .... (about) 80 ft.

From marl-band at oblique fissure-cave
to place where the strong M. cor-
a;i^«mf<m- tabular sinks to the shore
under the Castrum . . . . 62 ft.

From spot where strong M. cor-angui-
««m-tabular sinks to shore, to where
the upper of two strong nodular
flint-lines, 9 ft. apart, sinks to shore 180 ft.

From upper of two strong flint-lines, 9 ft.
apart, to point where the last Uinta-
crinus plate and the first Marsupites
plate were found . . . . 28 ft. 9 in.

From spot where the last Marsupites plate
was found to the upper of the two
marl - bands (470 ft. from stone
groyne) 48 ft. 9 in.

From upper of two marl-bands to top of
A. guadratus-chalk, at west end of
Seaford Head . . . (about) 170 ft.

At Seaford Head. Total . . 569 ft. 6 in.

Newhaven to Brighton.

The whole section can be worked when the tide is falling, and
the points where the tide has to be watched are at the east and
west corners of Friar's Bay, and the west side of Portobello. The
points at which we can leave the shore are at Telscombe Staircase

vHnx ctiaij: d? the eksush ctiast, ^^^7

(east of PanobeBo^ Partohelio. Saltdean, RotihurdetiTv, «ml
Bngbton. There is a feny across tht nvc: ai Xewiuiven, opposiie
the HarboDT Haiei Nd fresb^rater ^jnncs are seen on ihe
shofe.

StiD passinE wcsiward wt find samt fine diffe ai Xcwhavcn, in
the zone of A^nitcamax ouadnctu^.. and we trace :hesc on 10 a
point half-iraT herween Kottmgdean and Brighton, when* the ohfi^
is £aced with brick and snrmDmired tn a tall shaft. On the shoi^ts,
in front of ibe brick farmg. are two stronc; xrroyne^ There i^
probably, a piunjiing-siaiioi: bcrt. Some 450 yards west of this
we get the junction of the zones of A, cuadratus and Mm^upiif^
testudinariits, and from here to Brighton, a disitance of o\t^ a
mile, the base of the difis is in the latter zone. The distance
from Xewhaven to the pmnping-station is &i ini)e^ iSi> that
omitting the low clias :»erween Seaford and Xewhavcn, and those
at the west end of Seaford Head, which are also in the
A. quadratus-zoD^ we have nearly seven miles of continuous cliff-
section, all cut in the lower part of the zone of A, qte^tdran^s, U
stands to reason that, with such a length of section in one zone,
the beds must be practically horizontal, and such indeed is the
case. This is the most ertensif« section in England in the A.
quadratuS'ZJOn^

Cardiaster pillula, Echinoccfrys Tulgaris var. gihhus Actinih^A-
inax merceyi (never common). Ammonites hptophyUus^ together
with other characteristic fossils of a \aLSo\ A. quadra tysixycvt fauivi,
occur uninterruptedly throughout. The Br>o2oan l>cd ixx^urs on
both sides of Rottingdean Gap, hut beds of these organisms, of a
less prolific nature, are met with in other parts of the section.

This broad statement requires qualification, for there is one
very interesting and important exception to it, which it will Ih>
necessar)* to demonstrate in detail, as the occurrence of the
Marsupih's-\xix\A near Newhaven has never been susjKVtcd Iwfore.

Starting from Newhaven Fort, we find that the cliffs arc in the
Actinocamax (/uadraius-zonc^ full of Cardiaster piilu/a^ and the
other guide-fossils of this zone ; and this condition is maintained
as far as Old Xore Pomt, where the beds begin to rise to the west,
and a thin tabular rises from the shore. The rise in the beds is not
maintained, as there is a series of faults, which brings the tabular
to the shore again in the centre of the bay. The reefs from
Newhaven Pier to opposite Old Nore Point arc in the name
zone. Passing round Old Nore Point, we see a large bay, a inilo
long, the western end of which is marked on the 6 inch map (Mhccl
77) as Fnar's Bay. The reefs appear to lie at a lower level here,
and this idea is strengthened if we go out upon them and look
towards those at the western angle of Friar's Hay, for we scctn to
stand below the latter.

On these reefs, 550 yards west of Old Nore Point, wc found
Echinocorys vulgaris var. pyramidatus^ Echinoconus coniius^

33^

DR. ARTHUR ROWE ON THE ZONES OF THE

zone, when not damaged by the shingle, but the parts which are
in good order for working are limited.

There is no M, cor'iesiudinarium-i2ib\\\2it, as at Beachy Head
(Belle Tout), but much in the same position we find a thin closed
marl-band, which approximately marks the junction between this
zone and that of Af, cor-anguinum. The reader is referred
to p. 327, where the same zone at Beachy Head is discussed.
This section in no way differs from the other, save that it does
not look like M, cor-tesiitdinarium-chd\\i, and that several litho-
logical details which are present in one place are absent in the
other. There is no need to recapitulate the zoological details,
as they are the same in both sections. About 80 ft. of this chalk
is exposed, and we have worked the lowest part of it thoroughly,
and find no trace oi Holaster pianus-zoxiQ fauna. Aficraster shows
no evidence of nearing that zone.

At this point it will be convenient to put in condensed form
the lithological guides to the various zones at Seaford Head and
their measurements.

Measurements at Seaford Head.

Zone of Micraster]
cor-Ustudinarium. |

Zone of MicrasUr
cor-anguinum.

Zone of AfarsupiUs.

Zone of Actinocamax |
quadratus. "i

From lowest part of M. cor-Ustiidinarium-
zone to the oblique fissure-cave,
where the closed marl-band divides
this zone from that of M. cor-angut-
num .... (about) 80 ft.

From marl-band at oblique fissure-cave
to place where the strong J/, cor-
<7n^«/«i*m-tabular sinks to the shore
under the Castrum . . . . 62 ft.

From spot where strong M. cor-angui'
ifwm-tabular sinks to shore, to where
the upper of two strong nodular
flint-lines, 9 ft. apart, sinks to shore 180 ft.

From upper of two strong flint-lines, 9 ft.
apart, to point where the last Uinta-
crinus plate and the first Marsupites
plate were found . . . . 28 ft. 9 in.

From spot where the last Marsupites plate
was found to the upper of the two
marl - bands (470 ft. from stone
groyne) 48 ft. 9 in.

From upper of two marl-bands to top of
A. quadratuS'^TuWi^ at west end of
Seaford Head . . . (about) 170 ft.

At Seaford Head. Total

Newhaven to Brighton.

569 ft. 6 in.

WHITE CHALK OF THE ENGLISH COAST. 337

(east of Portobello), Portobello, Saltdean, Rottingdean, and
Brighton. There is a ferry across the river at Newhaven, opposite
the Harbour Hotel. No freshwater springs are seen on the
shore.

Still passing west^vard we find some fine cliffs at Newhaven, in
the zone of Actinocamax guadratus^ and we trace these on to a
point half-way between Rottingdean and Brighton, where the cliff
is faced with brick and surmounted by a tall shaft. On the shore,
in front of the brick facing, are two strong groynes. There is,
probably, a pumping-station here. Some 450 yards west of this
we get the junction of the zones of A. quadratus and Marsupites
tesiudifiarius, and from here to Brighton, a distance of over a
mile, the base of the cliffs is in the latter zone. The distance
from Newhaven to the pumping-station is 6^ miles, so that
omitting the low cliffs between Seaford and Newhaven, and those
at the west end of Seaford Head, which are also in the
A. (/uadratus-zont^ we have nearly seven miles of continuous cliff-
section, all cut in the lower part of the zone of A. quadratus. It
stands to reason that, with such a length of section in one zone,
the beds must be practically horizontal, and such indeed is the
case. This is the most extensive section in England in the A.
quadra fNS'Zone.

Cardiaster pillula^ Echinocorys vulgaris var. gibbus, Actinoca-
max merceyi (never common), Ammonites leptophyllus^ together
with other characteristic fossils of a basal A. quadratus-zone fauna,
occur uninterruptedly throughout. The Bryozoan bed occurs on
both sides of Rottingdean Gap, but beds of these organisms, of a
less prolific nature, are met with in other parts of the section.

This broad statement requires qualification, for there is one
very interesting and important exception to it, which it will be
necessary to demonstrate in detail, as the occurrence of the
Marsiipitt's-hdind near Newhaven has never been suspected before.

Starting from Newhaven Fort, we find that the cliffs are in the
Actinocamax quadratus-zont^ full of Cardiaster pilluia, and the
other guide-fossils of this zone ; and this condition is maintained
as far as Old Xore Pomt, where the beds begin to rise to the west,
and a thin tabular rises from the shore. The rise in the beds is not
maintained, as there is a series of faults, which brings the tabular
to the shore again in the centre of the bay. The reefs from
Newhaven Pier to opposite Old Nore Point are in the same
zone. Passing round Old Nore Point, we see a large bay, a mile
long, the western end of which is marked on the 6-inch map (sheet
77) as Friar's Bay. The reefs appear to lie at a lower level here,
and this idea is strengthened if we go out upon them and look
towards those at the western angle of Friar's Bay, for we seem to
stand below the latter.

On these reefs, 550 yards west of Old Nore Point, we found
Echinocorys vulgaris var. pyramidatus, Echinoconus conicus^

338 DR. ARTHUR ROWE ON THE ZONES OF THE

Micraster cor-anguinum^ Rhynchonella plicatilis^ and the large
Porosphara globuiaris in abundance, and we trace this rich fauna
nearly to the middle of the bay, where it dies out, and is replaced
by a less pyramidal form of Echinocorys^ mingled with some
sub-gibbus forms, and a smaller proportion of Micraster cor-angta-
num. We are now clearly in the transition area between the zones
oi Marsupites and Actinocamax qitadratus. Passing further on,
towards the west end of Friar's Bay, we come to an abundance
oi Echinocorys vulgaris wdiX, gibbus and finally to Cardiaster pillula.
So much for the reefs, which give the passage from the true A,
quadratus-zont fauna to that of the Marsupites-bsindy from the
Marsupites-hdind to the transition area, and from the latter to the
true A. guadratuS'Zone fauna again.

It is worthy of mention that this discovery of the Marsupi/es-
band was made, not by finding Marstipites itself, but by noting
the size, shape, and thickness of the broken tests of Echinocorys ^
and the presence of the large Porosphiera globuiaris. In
Echinocorys vulgaris var. pyramidatus^ the sides and base form an
acute angle, and the test is much thicker at the angle than in
Echinocorys vulgaris var. gibbus. The eye being attracted by this,
was at once impelled to a closer search, and Marsupifes was found
in abundance. The big dome-shaped form of Echinocorys was
also fairly abundant, and this was a further guide, as its relative
frequency is much greater in the Afarsupites-ionQ^ than in the zone
of A. quadratus.

Standing on the reef, we notice that our flint tabular-band
sinks to the shore at the middle of the bay, where, in 1899, there
was a great fall of rock, rich in Cardiastcr pillula and other
A, quadratus zon^ forms. It is clear that the cliff, in the western
half of the bay, must be in the true A, quadrat us-chalk ; and the
only point to decide is the nature of the beds between Old Nore
Point and the centre of the bay, where the flint tabular sinks
to the shore. On examining it we found one Marsupites basal-
plate, an abundance of the sub-pyramidal form of Echinocorys^
Rhynchonella p Heat Hi s^ six Actinocamax merceyi, and seven
Micraster cor-anguinufn^ but no Cardiaster pillula. We know that
at Seaford Head, and beyond the Pumping Station, near Brighton,
where we get a junction of the zones of Marsupites and Actino-
camax quadratus, we find the same fossils; so that it is clear that,
in this eastern part of the bay, we are in the transition area
between the two zones — an area which we can couple to the
Marsupites-hdiV\d, because the sub-pyramidal Echinocorys belongs
more to that bed than to the zone above, and that Micraster
cor-an^^uinum is one of the rarest fossils in the A, quadratus-zone.
It is evident, therefore, that we have here, for a distance of about
half-a-mile, a little exposure of Marsupites-zont in the cliff. The
value of correlating the reefs with the cliffs is very apparent all
along this section, and we only regret that the state of the tide

WHITE CHALK OF THE ENGLISH COAST. 339

and limited time, prevented us from examining the whole of the
reefs from the west end of Friar's Bay to Rottingdean, as it is
quite possible that we might get a trace of the Marsupiies-haLad
in other places at extreme low tide. Such parts of the reef
as were examined only revealed evidence of the ^. (/uadratus-zont.

Barrois puts all the section from Biding Gap to Brighton, with
the exception of a base of M. cor-anguinum-zone at the Seven
Sisters, and of M. cor-anguinum and M, cor-iestudinarium-zonts
at Seaford Head, into the Marsiipites-zont ; and the reason for
this course has been explained by the fact that he considered
the "spurious tabular and sponge bed," at Birling Gap, to be
analogous to the " VVhitaker 3-inch " tabular and the ** Barrois
sponge bed," at the top of the M, cor-anguinum-zont in Thanet.
The fact that he found Actinocamax merceyi^ at the Seven Sisters,
at Seaford Head, and between Newhaven and Brighton, gives
confirmation to this view, for this fossil occurs in the Alarsupites-
zone. We know, however, that it is equally a factor in the basal
A. quadratus-zone fauna. The occurrence of this fossil at the Seven
Sisters is very curious, and can only be explained on the suppo-
sition that it was found on a fallen block from the top of the
highest and most western " Sister," on the top of which we found
Uintacrinus and two Marsupiies plates. It must have come from
the very thin cap of Marsupites-h^nd. there, or it may have been
one of the very rare occurrences, low in the C/in/acmttis-haind,
such as we find at Margate.

Dr. Barrois told the writer that the whole of this wonderful
survey of the English Chalk was done at express speed, and that
very little time could be spent in collecting. Had he been able
to spend the same amount of time, which we have done, in
collecting, it is reasonable to assume that his arrangement of the
beds, from Birling Gap to Brighton, would have been different.
It must be remembered also that he had not the advantage of
using Uintacrinus as a zonal-guide. In any case, this is a small
defect in a work of marvellous insight and induction — a work
which has been the standard authority for over iwentv years, and
one which will stand the test of time and future investigation.

The danger of trusting entirely to a lithological feature is well
borne out here, and it shows that all zonal boundaries must be
fixed on zoological evidence, and on that alone.

Zone of Actinocamax quadratus.

FROM NEWHAVRN TO A POINT 550 YARDS WEST OF THE
PUMPINC; STATION, BETWEEN ROTTINGDEAN AND BRIGH-
TON ; INCLUDING THE 170 FT. OF THIS ZONE AT THE WEST
END OF SEAFORD HEAD AND THE LOW CLIFFS BETWEEN
SEAFORD AND NEWHAVEN.

This is a variable zone for fossils, being exceedingly rich at
some levels, and barren in others. It is always prolific in the

340 DR- ARTHUR ROWE ON THE ZONES OF THE

lowest part. This variability is well borne out in the Sussex
Coast.

The zone is characterised by a rather soft white chalk, greyish
in places, from admixture with marl, but often of a yellow colour,
from diffused staining with iron. Marl-bands, which often
weather out as open seams, are common, and so are tabular and
nodular flint-bands ; but the latter never occur with the regularity
of those in the zone of Micraster cor-anguinum. We know of no
chalk so full of tabular flint as this, and oblique fissures in the
chalk are frequently infilled with thin layers of flint. Slicken-
siding is sometimes present. Fossils from this chalk are by no
means easy to clean, on account of the adherent nature of the
marl, and are best worked in a moist state. We know of no
bed where the spines of Micraster and of Echinocorys are so
frequently adherent to the test, and this is doubtless due to the
intimate admixture of the marl with the chalk. The flints are
commonly of a pink colour outside, sometimes with a thick, and
at others with a thin, cortex ; but the colouration varies much even
in a limited area.

As before stated, the beds are practically horizontal all along
this extended section, and no lithogical features need be mentioned
until we pass the Electric Railway Station at Ovingdean, where
the beds clearly begin to rise gently as we pass to the west.
From this point we now take up the closer examination
of the section, as we are nearing the junction with
the Marsupitt5'Z\i2^y and all the beds east of this have been
proved, by collecting, to be in the zone of Actinocamax quadratus^
and rich in the characteristic fossils of that zone.

Opposite the fourth electric standard-pole, west of Ovingdean
Station, a thin tabular rises from the shore and we trace this to
the level of the top of the two stone groynes at the Pumping
Station. Below this tabular, Cardiaster pilliila dies out and
Echinocorys vulgaris begins to pass insensibly from the var. gibbus
to the var. pyratnidatus. It is clear that we are almost in the
Marstipites-band, There are no lithological features to guide us,
and we must trust here, as elsewhere, to zoological evidence.

Passing westward over the two stone groynes, we find an open
marl-band rising from the shore, between the second and third
electric standard- poles, on the west side of the more western
groyne. This marl-band forms the top of a wrought cave,
opposite the fifth pole, west of the groyne. Collecting between
this marl-band and the thin tabular, which is level with the top of
the groynes, we obtained fourteen examples of Echinocorys^ twelve
of which approached the shape of the var. pyramidatus^ and a
number of Rhynchonella plicatilis^ but no trace of Cardiaster
pillula. Still going west we found the first Marsupites plate, at a
spot opposite the ninth standard-pole. This gives us the point at
which the name-fossil comes in at the cliff, but we can safely take

WHITE CHALK OF THE ENGLISH COAST. 34*

the top o' the zone Op as hi^H as t^- mar'-'* :jd al ea .. ..^ .1

and our measurements will be uken from tnat level.

Leaving the clifi^ and examming the reefs, which, fmm their
position, are at a lower le%el in the zone, we coUecitrd Afiirsupites
plates as far east as the third sundard-pole, west of the groyne, and
east of this point we failed to trace them. The difference which
the slightly lower level of the reef makes is notable, for we find
that, taking; the distance between the poles as 50 paces, we discover
MarsupiUs 300 paces further east on the shore than in the cliff.

Returning to thecHff, it is c!ear that, directly repass the ninth
standard-pole, we are well in the J/arw/i/^j-band ; and the further
west we go the more obvious does it become, as the plates are more
abundant Towards Brighton they become fewer, for we are
getting lower in the ^farsup^ieS'h2iX\A. We looked for Uintacrinus
on the reefs facing the elephant-bed, but failed to find it.
MarsupiteS'\\BXt& were found there, so it is plain that we have not
quite reached the bottom of the Marsupites-ha^nd at this spot,
though this particular bed is 58 ft. thick.

There are but few pits near the coast. Two small exposures
on the south side of the road, between Portobello and Newhaven ;
a small roadside excavation, half-a-mile north-east of Rottingdean,
on the road to Newlands Farm ; a drain- trench between Brighton
and Roedean School ; and a large pit north-west of St. Mark's
Church at Brighton. All these are in the zone of Actinacamax
quadratus. The drain-trench runs from opposite a new house
called " Downside," which is a little to the east of the Golf-house ;
and in the chalk from this trench we found Ammonites Uptophyllus,
This was at a level of about 130 ft. from the shore, and a second
Ammonitss kptophyllus was found south of the Golf-house, on
about the 200 ft. contour-line.

Typical Fossils of the Zone of Actinocamax
quadratus as exposed in Sussex.

As this section only gives us a portion of the zone, it is
impossible to give the complete zoological divisions.

Cardiaster pillula jthroughout

Echinocorys vulgaris var. globus) ^

Actinocamax merceyi ) chiefly in lower
Ammonites leptophy!lus\ part

about 170 ft.
exposed.

Other characteristic fossils are Porosphirra^ Trochosmilia
{Cceiosmilia) iaxa, Bourgueticrinus (a special form), Serpuia
turbinella^ Eschara danae, Vincularia santonensis, and Crania
egnabergensis var. striata. There is a special un described form of
Cribriiina, which will shortly be figured. This is abundant in
February, 1900.] 25

342 DR. ARTHUR ROWE ON THE ZONES OF THE

every section of this zone which we have worked, and is highly
characteristic.

The almost complete absence of Micraster cor-anguinum is as
good a distinction, between this zone and that of Marsupites^ as
the most typical guide-fossils would be.

Cardiaster pillula occurs in bands, from the base to the top of
the chalk (170 ft.), as exposed here. This is essentially a
gregarious urchin, for when we find one example we generally
expect to see more. It is especially large and common at the
bottom of the zone, attaining the dimensions of an Echinoconus, but
we have found very large examples as high up as 1 20 ft. At a small
road-side exposure, on the Newlands Road from Rottingdean, we
obtained sixty-four in half-an-hour. This is essentially the domi-
nant fossil in this zone, and for so abundant a form its range is fairly
restricted to the upper and lower limits of the Actinocamax
quadratuS'Zon^. In Sussex we have never found it in the
MarsupiieS'h2in^ ; but at Margate, the writer has a solitary young
example, which was found below the " Bedwell-line," in the upper
part of the dinfacrinus-hsind. Mr. Griffith tells me that it is
occasionally found in the Beletnnitella mucronata-zone in Hamp-
shire. In our experience, this urchin becomes rarer in the upper
part of the zone, but we can always count upon sporadic occurrences
as far as the upper limit of the zone.

Echinocorys vulgaris var. gibbus is a very common fossil, and
an admirable zonal-guide. It is most abundant in the lower part
of the zone, and has a tendency to run in bands. It passes
insensibly from a sub-pyramidal form, at the base of the zone, to
a more truly gibbous form. As in all the higher zones, we find
a large dome-shaped form, rather more pointed in shape than
in the Marsupites-zone. It will be interesting to contrast the var.
gibbus in this zone with that in the zones of Holaster planus
and Micraster cor-tesiudinarium, Bryozoa are very abundant in
all three zones, and the adnate forms are so characteristic as to
afford a ready means of distinction between the zone of Actinocamax
quadratus and the two lower zones. Apart from this, however, there
are certain features of the test, which are sufficiently constant
to be worthy of mention. On the whole, the size of the Echino-
corys vulgaris var. gibbus in the A. quadratus-zon^ is decidedly
smaller than that in the two lower zones ; its base is notably flatter;
the sides of the test are straighter, and less rounded ; and the anus is
far more sub-marginal in position, instead of being marginal, as is
the rule in the two lower zones. Naturally, there would be no
difficulty in separating the two forms in the field, for both the
associated fossils and the lithology are so divergent that no con-
fusion could arise. Inexperienced collectors, however, often send
us urchins for determination, so that it is useful to have data
upon which we can rely in the study, and it is for this reason that
these observations are brought forward. There is no large dome-

WHITE CHALK OF THE ENGLISH COAST. 343

shaped form in the two lower zones. At the base of the zone we
find a very characteristic dwarfed pyramidal form, often no more
than 33 mm. in height, and 22 mm. in length. The writer has
found this in every basal section of this zone which he has worked ;
Dr. Blackmore records the same fact at Salisbury, and was the
first to call his attention to it. It is a perfectly characteristic form,
unlike anything else, and quite diagnostic of the base of the zone.
This small variety is an edition in miniature of Echinocorys
vulgaris var. pyramidatuSy even to the heaping-up of the apical
disc at the angle of the ambulacral junction.

Actinocamax merceyi is only found in the lower part of this
zone, and we have no record of its occurrence at a greater height
than 150 ft. from the base. Our specimen was obtained from
a fallen block ; but, from the position of the block, we can fix its
situation accurately. Another specimen was found, in situ^ 120 ft.
from the base. Both these were at Seaford Head. No trace of
Bekniniiella lanceolaia could be found at Seaford Head, where
we get the greatest thickness of the zone, though careful search
was made for it. The example of Actinocamax merceyi^ recorded
by Barrois from Seaford Head, was found at the 1 20 ft. level, for
we have a letter from him in which he indicates the exact spot at
which he found it. Our example was broken, but Dr. Barrois*
determination makes it clear that it was probably an example of
Actinocamax merceyi and not of Actinocamax quadratus. Our
example recorded from the 150 ft. level was also broken, and had
no alveolar cavity. We submitted it to Mr. Crick, who said that
it showed considerable resemblance to Actinocamax quadratus,
and possibly was that species. It was, however, too imperfect for
accurate determination. From previous experience we should
have expected that Belemnites found at this level would have
been of the form known as Actinocamax quadratuSy and that
those found at the base of the zone would be the typical
Actinocamax merceyi. Mr. Crick has seen all our Belemnites
from this coast, and he referred them all to Actinocamax merceyi,
with the exception of the single dubious example at the 1 50 ft.
level. There is no difference between Actinocamax merceyi as found
in the Marsupitesh2J\d and that found in the A, quadratus zont ;
and all that we can affirm as to its zonal value is that it is indica-
tive of either the lower part of the A, quadratus-zon^y or of the
Marsupites-handf as there is nothing to point to its occurrence in
the Uintacrinus-hdind in Sussex. The associated fossils will at
once give a clue, as there is never any difficulty in separating the
two zones in the field. We did not find Actinocamax merceyi at all
in the Marsupites-zont, at Seaford Head, but there the beds are
dipping at lodeg., and the section is a very short one in conse-
quence. We have found it at intervals all along the base of this
zone, from Newhaven to the Pumping Station between Rotting-
dean and Brighton.

344 I>R' ARTHUR ROWE ON THE ZONES OF THE

Ammonites leptophyllus is found in considerable numbers
in the base of this zone, from Newhaven to the Pumping
Station. Whether it is the same species as that which occurs
in such abundance in the Brighton Marsupifes-hsindy must be
left to a specialist in cephalopoda to decide. It reaches an
immense size in Sussex, frequently 4 ft. across, and one gigantic
example, which we measured, was 66 inches in diameter. This
establishes a record for Chalk Ammonites. We found none, in
sitUy at Seaford Head in this zone. The highest range which we
have recorded is at the drain-trench south of " Downside." We
have something like 40 ft. of the Marsupifes-bsind in the cliff at this
point, so the Ammonites must have been respectively about 90
and 150 ft. above the base of the Actinocamax quadratus-zon^.
This is a very high occurrence, and we have been unable to
detect any others so high up in the cliff.

Porosphcera is also a good guide-fossil. Porosphtzra giobularis
is often large, but not so large as in the Marsupites-iont, Poro-
sphara woodwardi and P, pileoius are of large size and great
numerical strength. We regard an abundance of Porosphara
woodwardi of large size as especially suggestive of this zone.

Parasmilia {Ccelosmilia) laxa is highly characteristic of this
zone, and as it is generally abundant, is a good guide - fossil.
We have found it in every section in this zone. The corals are
generally small. Other common forms are Parasmilia fitioni zxid
P, cylindrica,

Bourgueiicrinus has a characteristic head in this zone, is
always abundant, and an excellent zonal-guide. It occurs in all
sections in this zone which we have worked. This form Dr. Black-
more first introduced to the writer's notice, before he had much
experience in this zone, and he gladly records the fact of its
universal occurrence and usefulness. There is also a dumb-bell-
shaped columnar which is characteristic, hut not so common. This
dumb-bell-shaped columnar is merely an exaggeration of the
dominant columnar of the zone, which is longer and thinner,
with expanded ends and a contracted centre (PI. VIII, Fig. 11).
Bourgueticrintis cequalis is found, and sometimes reaches a large
size. It is not peculiar to this zone, but is found in the zones of
Marsupites testudinarius and Micraster cor-anguinum. This also
occurs in all sections.

Serpula ilium is of large size (6 to 20 mm. in its largest
diameter), and is very common and characteristic in Sussex
Serpula turbinella is not so common as the last, but is a useful
guide, though not confined to this zone.

The Bryozoa are very abundant and characteristic, and in our
hands have proved one of the most useful of zonal guides ; but as
several of the most characteristic forms are not figured, it is
impossible to refer to them. They will shortly be figured and
described by Mr. R. M. Brydone and the writer.

WHITE CHALK OF THE ENGLISH COAST. 345

Vincularia santonensis is quite a characteristic form, and
Eschara danae is even more so. The latter can be determined
without the aid of a lens, so marked are its characters. Vincularia
disparilis is found in great profusion in this zone, but as it is also
rather common in the two zones immediately below, it can hardly
be regarded as a reliable zonal guide. There is also an
undescribed form of Cribrilina^ which is equally abundant and
characteristic. All these forms are prevalent in every section of
this zone which we have worked.

In Sussex, Rhynchonella plica tilts occurs in great abundance
in the Marsupites-b^ind^ and, to a less extent, in the extreme base
of the A, quadratuszox\^^ being large and flat in both instances.
When we pass well into the A. quadratus-zont^ however, it
becomes smaller and more inflated, and the var. octoplicata is the
dominant form. Rhynchonella limbata is found in this zone, but
is not so common as in the Belemnitella mucronata-zon^. Crania
egnabergensis var. striata is common in this zone. It would
appear that in this zone, and in that of Marsupites, the costae tend
to become fewer, leading up, as it were, to the var. costata, which
is only found in the zone of B, mucronata.

There is a band of Ostrea wegmaniana in the passage-bed
between the zones of Marsupites and A. quadratus in Sussex.
Ostrea lateralis^ though by no means confined to this zone, reaches
its highest development here. It extends, with decreasing fre-
quency, as low down as the zone of T, gracilis, Ostrea lateralis
var. striata is, in our experience, only found in the zone of A,
quadratus.

Sponges are very abundant and well preserved, and are by no
means devoid of interest as zonal-guides.

Whether Actinocamax quadratus is a good name-fossil for this
zone is open to question. Were not Belemnitella mucronata such
an excellent name-fossil for the zone above, thus giving a con-
tinuity between the two species, it would be much better to do
away with the present name for the lower zone, as far as England
is concerned.

Actinocamax quadratus in upper part ) c n j- 4 m:/f /

. .. ^ • • 1 r J iJone of Cardtaster pillula,

Actinocamax merceyt m lower part . ) ^

The above scheme would much better meet most English
sections with which we are acquainted, as Actinocamax merceyi is
so frequently a rare fossil. However, it would seem to be a pity
to break into the continuity of the Belemnites, and we have, there-
fore, kept to the old arrangement. As long as we recognise the
exact mutual relationship of the various well-defined species of
Belemnites, it matters but little by what names we call the zones
which mark their individual horizon. In other districts Belemni-
tella lanceolata is found in the lower part of the zone, but, like

346 DR. ARTHUR ROWE ON THE ZONES OF THE

Actinocamax merceyt\ it is not of universal occurrence. Bekm-
nitella ianceolata is found in the lower two-thirds of this zone at
Salisbury, according to Dr. Blackmore, and Mr. C. Griffith tells
me that it is a rare fossil in Hampshire, where, in contradistinction
to Salisbury, it occurs at the very top of the zone, and is even
occasionally associated with examples of Belemnitella mucronata.
The most careful search failed to reveal a single example in Sussex.

Zone of Marsupites testudinarius.

FROM 550 YARDS WEST OF THE PUMPING STATION TO

BRIGHTON, AND INCLUDING THE SHORT EXPOSURES AT

SEVEN SISTERS AND SEAFORD HEAD.

The exact position of the top of this zone, both in the cliff,
and on the reefs, near Brighton, has already been indicated on
p. 340, and need not be recapitulated. The chalk is soft and
marly, with nodular and tabular flint-bands and marl-seams. No
one could distinguish this chalk from that of the zone above, and
the only difference is that the flints have a thin white cortex
instead of a pink one. Even this distinction fails one at certain
places in the section. Anything more unlike the MarsupUes-
chalk of Margate or Salisbury it would be impossible to imagine.
There is no lithological break to divide this zone from that of
Actinocamax quadratus.

The only way to get an idea of the thickness of the whole
zone is to correlate the sections at Brighton, Seaford Head, and
the Seven Sisters. The thickness of the exposure of the
Marsupites-hTind at Brighton is 58 ft. The thickness of the
same band at Seaford Head is given as 49 ft., and, considering
the difficulty of obtaining zoological ^vidence at this place (and
measurements are only made on these grounds) on account of the
battered state of the cliff, the measurement comes out pretty well.
How much more of the Marsu/>ifes-band there is at Brighton it
is impossible to say, as no Uintacrimis could be found either in
the cliff or on the reefs. That Uintacrinus does occur somewhere
in the Brighton area may be inferred from specimens of that
fossil in the Brighton Museum, which are described as Marsupites^
and stated to have come from Brighton. It is probable that the
band will be found on the foreshore at Brighton. Barrois says
that Marsupites occur at Shoreham, and this fact, coupled with
the known dip of the MarsupiteshdiUd. at East Brighton seems to
indicate a gentle undulation such as we have described in Friar's
Bay, and one which would expose a few feet of the lower band
{Uintacrinus-h2J\6) in the centre of the arch, eg,, Brighton,
somewhere just west of the Aquarium. The thickness of the
C/intacrinus-b2ind is given as 28 ft. 9 in. Further, and more
fortunate, search may increase the downward measurement some-
what. So little is at present known of Uintacrinus that it is

WHITE CHALK OF THE ENGLISH COAST.

347

impossible to expect much evidence of its occurrence in the
Sussex sections, save those which we have recorded. Anyone
working in the Brighton area would do good service by examining
the reefs at low water.*

The Broad Zoological Divisions of the Zone of
Marsupites testudinarius.

Marsupites testudinarius

Actinocamax merceyi

Ammonites leptophyllus

Echinoconus conicus

Echinocorys vulgaris var. pyramidatus

Terebratulina rmvei

Bourgueticrinus, a special form |

Uintacrinus

Echinocorys vulgaris var. pyramidatus

BourgueticrinuSj the same special form f

Terebratulina rowei '

AfarsupiteS'hsLnd

maximum thickness

exposed, 58 ft.

\ UintacrinuS'hsLnd
[maximum measure-
ment yet obtained,
28 ft. 9 in.

A comparison of this table with that given for the Thanet
coast will at once afford a striking contrast (p. 296). It will be
seen that Ammonites leptophyllus^ instead of being associated with
the UiNtacrinus'b2Lnd, is referred almost entirely to the Marsupites-
band, and that it, or a form much resembling it, extends upwards
into the /.one of Actinocamax quadratus. We have but one record
of the occurrence of the Ammonite in situ in the Uintcurinus-hsxid,
Under the Seven Sisters we found several fragments resembling
an Ammonite 'n very bad preservation. One of these we sent up to
Mr. Crick, who unhesitatingly referred it to that genus. Two of
these blocks we can localise with certainty, for they occurred in a
recent fall which was clearly in UintacrinuS'Chdi}k^ with the merest
trace of Micraster cor-anguinum-chalk below it. The turf-cap was
still attached to the top of the fall, and under the turf were abundant
Uintacrinus plates, but no Marsupites plates. The other blocks
were on the shore, and we could not tell their origin. No trace
of an Ammonite have we found in situ throughout the whole long
stretch of M. cor-anguinum-chalk. We carefully record these
facts, giving them for what they are worth, in the hope that other
observers may throw further light upon them. Dr. Barrois tells
the writer that Ammonites leptophyllus is not found in France.
We have found no trace of Aptychus in this zone, or in that of
Actinocamax quadratus^ in Sussex.

For years past we have heard of Marsupites being found at
Rottingdean, and its occurrence there has always been a puzzle.
Repeated search in the cliff has failed to reveal to us a single

* Since writinij; (he above, Mr. W. McPherson has found a plate of Umtacrinus on the
reef facing the EU.phant-bed at Hrightun. It is clear, therefore, that we have there the
junction of the Marsu/itts- znd l/iMUKriHUS-bzads,

348 DR. ARTHUR ROWE ON THE ZONES OF THE

plate between Rottingdean and the ninth electric standard-pole,
west of the groyne at the Pumping Station.

Examination of the reefs, between Rottingdean and the
Pumping Station, has led to a similar negative result. The land-
lord of the " White Horse," Rottingdean, tells us that he has
found whole tests in the rolled fallen blocks under " Greenway,"
which is between Rottingdean and Ovingdean Electric Station.
We know that the blocks from the Elephant-bed, at Brighton,
travel as far as this, and we can only account for the occurrence of
Marsupites on this assumption. He has never found them in falls
from the cliff, as was reported. We know that there is a strong
westerly drift along this coast. The " Peruvian," laden with
ivory-nuts, was wrecked at Seaford on February 8th, 1899, and in
November, 1899, these nuts were found on the shore as far as
Eastbourne.

Actinocamax merceyi does not extend so low in the Marsupites-
band as in Thanet. Its maximum of occurrence appears to be in
the upper 20 ft. of the Marsupites-h^LiMl, and the ext-eme base of
the A, quadratus-zon^. We had not time to thoroug ily work the
reefs close to Brighton, but a rapid examination of hem gave a
negative result. We found no Actinocamax me ceyi in the
Marsupites-zont at Seaford Head, or at the Seven S isters. The
two places where we found most specimens, were immediately
west of the Pumping Station and in the eastern half of Friar's Bay,
where the passage-bed between the zones of Marsupites and A.
quadratus occurs. Actinocamax merceyi is fairly common on the
fallen blocks near Brighton, but we have not succeeded in finding
one in situ lower than 20 ft. down in the Marsupites-zone.

We have found no trace of Actinocamax verus throughout the
whole section, though we have especially searched for it. Mr.
W. McPherson has, however, given me a small broken Belemnite,
which he found on a rolled block close to Brighton. Mr. Crick
has identified this as Actinocamax verus. Not only is it absent
in the Uintacrinushdrndf but it has not been found in the zone
of Af. cor-anguinum in this locality, though it occurs in Hants,
and in Norfolk, according to the testimony of Mr. C. Griffith and
Mr. W. Hill. It is a rare fossil in both these counties. Since
writing the above, Mr. Griffith has kindly shown me several of
these Belemnites, and they appear not to be examples of Actino-
camax vertiSy but of a form closely resembling it. In a recent
letter, Mr. Hill states that he only found a few fragments of
Belemnites, resembling Actinocamax verus in size an i shape, but
that they were too imperfect to warrant an exact determination.
Mr. (t. E. Dibley states that Actinocamax verus is found in the zone
of M. coranguinum in the Gravesend district. We have seen these
specimens and they undoubtedly belong to this species. Dr.
Barrois tells the writer that, in France, Actinocamax verus is found
in the upper part of the zone of M, cor-anguinum^ and that it

WHITE CHALK OF THE ENGLISH COAST. 349

ranges up into the Marsupites-uon^ He does not look upon it
as essentially a Marsupites-zont form. Marsupites testudinarius is
a rare fossil, and there are very few sections of this zone in
France. He further adds that it is very difficult in France to
separate the zones of Micraster cor-anguinum and of Marsupites,

Echinoconus conicus is not found in a band at the base of the
zone, as in Thanet, but on the contrary is rare here, and is only
found with any frequency in the Marsupitts-hzxiA^ and is far more
common in the top of that band than it is in Thanet. It is
nearly always of the rounded type — the forma conica-r-^'f^^ we
found no examples of the large forma pyramidalis^ and even well-
marked smaller specimens of the last-named type, which is the
commonest form in Thanet, are comparatively rare. No
Echinoconus was found in the zone of Actinocamax quadratus,

Echinocorys vulgaris var. pyramidatus is as certain a zonal-
guide here as in Thanet, and its maximum degree of acumination
is reached where Marsupites plates are thickest. It is here that
we get the remarkable heaping-up of the apical disc, together with
the bossing at the summit, where the ambulacral areas converge,
so notable in extreme examples. There is no band of this urchin
here, but it occurs uniformly and frequently throughout.

Terebraiulina roivei is a perfectly reliable zonal guide in every
section which we have worked. We found twelve examples on
the little bare patches on the top of Seaford Head and the
Seven Sisters ; so it seems to be common in both the Marsupites-
band and the Uintacrinus-hzxid. In two hours we found twenty-
three examples in the Marsupites-hsind at Brighton and during this
time we only saw two specimens of Terebratulina striata.

The relative positions of Marsupites^ Uintacrinus^ Ammonites^
Actinocamax merceyi^ A. verus, and Echinoconus^ at Salisbury,
correspond closely with those at Margate, according to Dr.
Blackmore. On the other hand Mr. Griffith states that Echinoconus
is not a characteristic fossil of this zone in Hampshire. We see,
therefore, that the zone is rather fickle in its faunal relations, and
that the only constant factors are Marsupites occurring in the
upper part and Uintacrinus in the lower. There is no ** Barrois
sponge-bed " at Salisbury, nor in Sussex. In a flinty chalk like
that of Sussex it would be idle to look for a " Bedwell-line." The
Salisbury J/arj«///^j-chalk is, like that of Margate, soft, flintless,
and devoid of marl.

What has been written concerning Bourgueticrinus^Porosphara
Kingena lima^ and Serpula turbinella^ in the Thanet section,
applies equally well here. On the other hand Rhynchonella
plicatilis^ so rare at Margate, is found in great profusion through-
out the Marsupites'hand. It is especially common at the top ol
this band and ac the base of the Actinocamax gucutratus-zon^.

There is a great development of Doryderma ramosum in this
zone at Brighton, and the flints are full of this sponge.

350 dr. arthur rowe on the zones of the

Measurements of the Zones in the Sussex Coast.

The approximate measurements in the White Chalk of the
coast of Sussex are as follows :

Zone of Actinocamax quadrat us (as exposed) 1 70 ft.

„ MarsupUes iestudinarius , . . 77 ft. 6 in

„ Micraster cor-anguinum . . . 242 ft.

„ Micraster cor-testudinarium . . 109 ft. 6 in

„ Holastcr planus . . . 48 ft.

„ Terebratulina gracilis . . .170 ft.

„ Rhyfichonella cuvieri . . . 100 ft.

917 ft.

Sheets of 6-inch Maps employed (Ordnance Survey).

It is impossible to understand coast-sections aright, or to work
them conveniently, without the 6-inch maps of the Ordnance
Survey. If each worker will put in his zonal junctions on the
map, as ascertained by purely zoological evidence, he will do
much, not only to check our results, but to supply our deficien-
cies. To this end we append the numbers of the sheets
necessary.

Birchington to Pcgwell
Kingsdown to Folkestone .
Eastbourne to Brighton

Sheets 25, 26, 38, 37.

Sheets 68, 75.

Sheets 80, '^i^ 82, 79, 78, 77, 66.

Conclusion.

It might have been better to have described the sections in
each county from below upwards, instead of reviewing the beds,
as we pick them up, passing from east to west along the coast ;
but there has been no time to recast the paper.

Long though the paper undoubtedly is, the writer is conscious
of many omissions, not a few of which could readily have been
supplied, had there been more time at his disposal. The lists in
no sense represent the material collected, as there are several
thousand specimens which it has been impossible to clean and
accurately determine. Zoology has been so long the patient
handmaiden to lithology, that no excuse need be offered for
showing cause whereby the two subjects may be placed on an
equal footing.

In working a vast coast-section, like the one under considera-
tion, with its extensive zonal range, one of the most interesting
problems which arises is the zonal variation manifested in the
bulk of the common fossils. We have traced this variation in
some of the more important groups, but much more might be
written, did space permit, concerning the Brachiopoda and

WHITE CHALK OF THE ENGLISH COAST. 351

I^mellibranchia. Indeed, there is hardly a group in which this
zonal variation may not be traced with profit, and it is hoped that
this may be done in a subsequent communication. The main
difficulty is one of illustration, as however well the individual
collector may know the variations they can only be made useful
to other workers by means of plates.

The Chalk Lamellibranchia are in such a chaotic state that no
excuse need be offered for determinations which are not strictly
accurate. The same remark applies to the Bryozoa, which are
so useful as zonal guides. Mr. Henry Woods is dealing with
the former, and Dr. J. W. Gregory is describing the latter (" Cat.
Creta. Bryozoa," Brit. Mus., 1899), so that both these interesting
groups will be placed on a secure footing.

It will probably be noticed with surprise that no direct allusion
has been made in this paper to vertebrate remains. The omission
is intentional, for even shark's teeth are, comparatively speaking, so
rare, that no reliance can be placed upon them as zonal guides in
cliff-sections. Quarry-workers, like Mr. G. E. Dibley, may feel
inclined to traverse this contention, for in certain quarries in Kent
the crushing-teeth of sharks are found in great abundance. Still,
these occurrences are purely local, and, as such, have but little
value in tracing a zonal range.

On reading the manuscript again the writer feels that, while he
has laid all possible stress on the extreme importance of studying
these rocks from a purely zoological standpoint, he may possibly
have failed to give sufficient value to the lithological features.
This view has been strengthened by some remarks made by the
President, Mr. Teall, when the paper was read. While no
testimony, however powerful, can exaggerate the wonderful way in
which the zonal theory is established by careful collecting over a
wide area, it is equally true that, in many instances, the litho-
logical features are fully as constant and rigid in their persistence.

The ideal coincidence of a constant zonal fauna and a constant
lithological facies is well brought out, in the south of England, in
the case of the zones of Rhynchonella cuvieri^ Holaster planus^
Micraster cor-fesiudinarium^ M. cor-anguinum^ and Belemnitella
mucronata. Local variation, of course, plays its part even in these
zones ; but the fact remains that we can generally recognise the
zones from the appearance of the chalk alone, and that the fossils
act as confirmatory evidence. Still, in the light of accumulated
zonal experience, nobody would venture to zone these beds, save
on the evidence of their fauna, and zonal boundaries can only be
established by patient collecting.

It will be noticed that no attempt has been made to make the
thickness of the several zones correspond in the different districts
herein discussed ; and that, however tempting it may be to adopt
lithological features as division-lines, they have been discarded,
unless the zoological evidence clearly corresponds with them.

352 DR. ARTHUR ROWE ON THE ZONES OF THE

The zoological evidence here adduced has been obtained in
the south of England coast-sections alone, and the writer disclaims
any intention of making this evidence govern the distribution of
fossils in other localities. He merely brings forward data obtained
by personal collecting over a wide area ; and as other sections
are worked, further data will be secured, and correlated with them.
The present inquiry must be regarded merely as an instalment up
to date, as the zonal survey only embraces the coast-line of two
counties. But, as far as they go, the writer believes that the
conclusions are substantially accurate ; and certainly no pains
have been spared to avoid hasty generalisation, for the whole of his
holidays, during the last ten years, have been devoted to rigid
zonal-collecting, and the study of zonal variations.

No mention has been made of the terms Upper and Middle
Chalk, or of their continental equivalents, as, save for mapping
purposes, they can have but little value ; for to any worker, who
knows his fossils, the existing zonal divisions are all-sufficient.
For convenient reference a table has been compiled by
Mr. Sherbom, and will be found on p. 293. Further, no
two observers seem to agree upon the exact point at which
the base-line of the so-called Upper Chalk shall be placed.
The fauna of the Chalk Rock seems to be the cause of all this
uncertainty, on account of its "Cenomanian affinity." If this
somewhat inconstant bed, with its peculiar fauna, be looked upon
as an interpolation, in no way affecting the integrity of the fauna
of the Holaster planus-zon^ associated with it, much of the diffi-
culty is removed. As Echinocorys and Micraster, the two most
abundant and characteristic fossils of the higher beds, only appear
in earnest at the base of the Holaster pianus-zone^ it would be
reasonable to place the base of the Upper Chalk there. Another
phase of the difficulty has arisen in the desire to find a hard rocky
bed wherewith to base the Upper Chalk, as a parallel to the
rocky base of the Rhynchonella cuvieri-zont. It has been shown
that the Chalk Rock is not always present, in a lithological sense,
and, therefore, a lithological boundary of such inconstant occur-
rence can hardly seriously engage our attention. Though the
Chalk Rock may be determined by microscopical examination,
even when it is not strongly developed to the naked eye, such
evidence, though of scientific interest, cannot avail us much, as it
is useless in the field.

To many fellow-workers the writer would accord his grateful
thanks, and above all to Mr. C. Davies Sherbom, who has shared
his field-work during the past four years, and to whom he is
indebted for the excellent coast-section, without which the text
would have but little value. Much valuable information and kindly
assistance has been given by Dr. Barrois, M. Jules Lambert,
Mr. Jukes-Browne, Dr. G. J. Hinde, Dr. A. Smith Woodward,

WHITE CHALK OF THE ENGLISH COAST. 353

Mr. H. Woods, Dr. Blackmore, Mr. Griffith, Mr. R. M. Brydone,
General Cockburn, Mr. E. Westlake, Mr. G. E. Dibley, and Mr. W.
Gamble, and the writer cordially acknowledges help so willingly
given.

To Dr. J. W. Gregory and Dr. F. L. Kitchin, who havs
described the two new species in the Appendices to this paper, and
to Mr. F. A. Bather and Mr. G. C. Crick, who are working on
material contributed by the writer, sincere thanks are due. Mr.
Bather has also kindly supervised the drawing of Uintacrinus
plates for the paper, and is responsible for the description of the
figure on p. 298. It was felt that a good figure of this essential
guide-fossil would be of real assistance to zonal workers, and that
the paper would be incomplete without it.

APPENDIX A.

Rv Prof. J. W. GREGORY. D.Sc, F.G.S., F.Z.S.

ZEUGLOPLEURUS ROWEI, n.sp.

Diagnosis. — Test very small, turban shaped ; flat-based, sub-
conical above ; tall in proportion to its size ; circular or
subpentagonal in outline.

Apical system prominent ; thickened on the margin beside
the periproct. Madreporite covering three-quarters of its genital.
Posterior radial marked by a median depression. Periproct
pentagonal.

Ambulacral plates numerous ; epipodia highly oblique. The
plates begin as simple primaries, but soon become compound
plates of two fused primaries.

Interambulacral plates about 8 to 9 in each series.

Epistroma of very abundant granules, which are crowded and
subequal in size. A very small primary tubercle occurs in the
ambital interambulacral plates, and lines of granules radiate from
it. No ridges. Scrobicular area well marked and depressed.

Peristome large ; subcircular.

Dimensions B.M.75,556^ Dr. Rowers B.M.75,556fl

Height of Test 3 mm. 4 mm. 5*5 mm.

Diameter of Test 4*25 mm. 5-5 mm. 8 mm.

Diameter of Peristome (unseen) 175 mm. (unseen)

Distribution. — Upper Chalk, Charlton ; Marsupites-zone, Mar-
gate ; Micraster cor-anguinum-zont^ between St. Margaret's Bay
and Kingsdown.

Affinities. — This small urchin is most nearly allied to
Zeuglopleunis costulatus^ Greg.,* from which it differs by being

* J. W. Gregory, On ZeuglopUurus^ a new genus of the family Temnopleuridc from
the Upper Cretaceous. Ann. Mag. Nat. Hist.^ ser. 6, vol. iii, pp. 490-500; 1889. See
p. 495.

354

DR. ARTHUR ROWE ON THE ZONES OF THE

taller in proportion to its diameter, having a larger peristome, a
pentagonal periproct, and no ridges connecting the primary
interambulacral tubercles. The epistroma is altogether more
primitive.

The characters and the small size suggest that the echinid
may be a young form ; but as Dr. Rowe has found several
specimens which are all small, it is probably entitled to specific
distinction.

The British Museum Collection includes two specimens from
Charlton (No. 75,556, a and b\ which in 1889 1 accepted as young
forms of Z costulatusy and on whose evidence alone I quoted that
species as occurring in " Mid Chalk of Charlton " (op, cii,^
p. 496) ; the peristomes in these specimens are covered by chalk
matrix. It follows that Z. costulatus is now known only from one
specimen, namely, that found in Chalk Marl at Glynde, Sussex
(Brit. Mus., E 4,365).

Fig. I. 7 YiG. 4.

Zeugloplkurus rowei, Gregory.

EXPLANATION OF FIGURES.

Fig. I, Dr. Rowe*s largest specimen, side-view x 7 diam. ;
Fig. 2, the same from below, x 8 diam. ; Fig. 3, the apical disc
of the same, x 15 diam. ; Fig. 4, two of the ambital, interam-
bulacral plates of a larger specimen (No. 75,556a) in British
Museum (Nat. Hist).

WHITE CHALK OF THE ENGLISH COAST. 35$

APPENDIX B.

Hv F. I^ KITCHIN, M.A., Ph.D., F.G.S.

TEREBRATULINA ROWEI, n.sp.

Ph. VIII, Figs. 1-5.

Description. — ^The shell is small, very variable . in form, and
oval to bluntly triangular in outline. The length is usually
greater than the breadth, but these dimensions are occasionally
found to be equal in full-grown specimens. The dorsal valve
often almost equals the ventral in depth, and many individuals
bear a relatively inflated aspect. The maximum thickness is
usually situated posteriorly to the middle, and the greatest breadth,
except in some young individuals, always falls within the anterior
half of the shell.

The surface is ornamented by a variable number of delicately
nodose radial ribs which, with the advancing growth of the shell,
increase in number by dichotomy and insertion. In the largest
specimens examined (between 5 mm. and 6 mm. in length),
the number of ribs at the margin of the dorsal valve varies
from thirty to thirty-six. Concentric lines of growth, scarcely
visible in the younger stages, sometimes give rise to the ap-
pearance of imbricating lamellae having their edges anteriorly
directed.

The dorsal valve is most inflated in its posterior half, and
towards the anterior margin becomes more or less flattened,
often to form a shallow median longitudinal depression widen-
ing at the front. This depression is a variable feature ; if
is usually weak and at times scarcely developed, and then
only as a character of the adult shell, while in other cases it
may be traced back to the middle of the valve in a full-grown
individual.

The ventral valve occasionally shows a weak median
longitudinal arching or fold towards the anterior margin,
corresponding to the median depression of the dorsal
valve.

The hinge-line is either straight, or more often, very gently
curved. The commissure describes laterally a simple course, and
in fully-grown examples becomes deflected at the front to form a
shallow bow or very obtuse angle corresponding to the form of
the frontal dorsal median trough.

The beak is acutely pointed and strongly incurved, but
seldom so strongly as to grasp the dorsal umbo. The fora-
men is minute and of elongated form; the deltidial plates
are obscure.

356

DR. ARTHUR ROWS ON THE ZONES OF THE

Dimensions, —

Length.
3-8
4
4

57
6

5-5
5-8
6

Breadth.
3
3

3-8
57
5
5
5-8

Depth.
2 mm. I
2 „ \
2-8 „ )
3*2 „ J^
3*2
3
3

From the
UintacrinusAiaLTi^,

I From the

\ AiarsupitesAxLTid,

(From the zone of
Actinocamax quadratus.

This description is based on the examination of fifty
specimens.

Distribution, — This form is confined, so far as we know, to the
zones of Marsupites testudinarius and Actinocamax quadratus. In
the former zone it is of common occurrence, and in the Marsupites-
band near Brighton it is much more frequently met with than
Terebratulina striata^ Dav. (see p. 349). It appears to be rare, how-
ever, in the zone of Actinocamax quadratus. Its distribution as now
known in the Marsupites-chdXk is as follows : Uintacrinus-bsind
and MarsupiteS'hsLnd at Margate, Seaford Head, and Dorset
Coast; MarsupiteS'bsind at Brighton, and C/intacrinus-hsind at
Seven Sisters Head (Sussex). From the zone of Actinocamax
quadratus this form has been collected in the base of the zone at
Rottingdean (Brighton), Seaford Head, Newhaven, and Pauls-
grove Pit, Portsdown Hills (Hants). It has been found by Dr.
H. P. Blackmore at the base, and also higher up in this same
zone at East and West Harnham, near Salisbury.

Remarks, — This beautiful and characteristic form, in its general
outline, in the inflation of the valves and the anterior depression
Df the dorsal valve, approaches most closely to Terebratulina
triangularis^ Dav.* (= T, striata var. triangularis^ Ether. f). It
is, however, readily distinguished from the latter by the somewhat
coarser character of the ornamentation, the less prominent, more
acute, and strongly-incurved beak, and by the minuteness of the
foramen. Of the forms united by U. SchloenbachJ under the
name Terebratulina rigida^ our type appears to bear most
similarity to those North German occurrences included by F. A.
Roemer§ under the name Terebratula ornata^ differing, however,
by the narrower, less prominent, more acutely pointed and more
strongly-incurved beak. Terebratulina rowei csLnnot be confounded
with that form which characterises the "zone of Terebratulina
gracilis " ; the latter is distinguished by a more delicate type of
ornamentation, a weaker degree of inflation, a flatter dorsal valve,
and a broader, blunter, and more strongly-incurved type of beak.

♦ Davidson, " Mon. Brit. Foss. Brach." vol. v, pt. iii (Appendix to Suppl.), p. 245, PI.
xviii, fig. 3j 1884 {PaUtontofCraphical Society).

t Ethendge, Appendix A, in Penning and lukes-Browne, "The Geology of the Neigh-
bourhood of Cambridge" {Mem. Geol. Survey}^ p. 148. PI. iii, fig. 15, 1881.

X U. Schloenbach, Beitriige zur PalSontoloeie der Jura- und Kreide-Formalion im nord-
westl. Deutschland, 11, PaUtontograpkica^ Ba. xiii, 6e Lief, p. 384, 1866.

§ " Verstein. des Norddeutsch. Kxeidegeb," p. 40, 1841.

WHITE CHALK OF THE ENGUSH COAST. 357

It must be noted that an appreciable change is observable in
the dimensions attained by this shell as it is traced upwards
through its vertical range. Specimens collected from the
UififaainusAxind are more diminutive, on the average, than those
taken from the Afarsu/fifes-baind, while a comparatively small
percentage of individuals in this latter band attain to the dimen-
sions of the few examples hitherto known from the zone of
Actinocamax quadratus.

With regard to the affinities of the type before us, it is difficult
to speak. It appears to stand isolated, and there are apparently
no links to connect it with those forms which, while absent from
deposits higher than the Totternhoe Stone in England, and the
lower " Planer " in North Germany, appear to approach it most
closely in general habit.

It is quite a matter of doubt, indeed, in how far the actual
points of similarity in outward characters, as above noted, are to
be taken as indicative of relationship ; and in view of the wide
chronological gap separating the occurrence of these types, such
characters as the latter possess in common cannot alone be
taken as proof of close genetic relationship.

NOTES TO LIST OF FOSSILS.

It is felt that, while it is essent'al to record the zonal ranc^e of any given
fossil, it is equally important to indicate the comparative Sequency of its
occurrence. The following abbreviations have been employed :

C. common ; R.C. rather common ; R. rare ; R.R. rather rare.

No Bryozoa are included in the list, as time does not permit one to work
out the thousands of specimens in the collection, so as to show their zonal
distribution. This will be done in a subsequent communication.

The free and adnite Ceriopora, and other allied forms, are not listed, partly
for the same reason, and partly because there is no reliable work of reference
to consult.

The Serpulx cannot be fully recorded, as many common forms cannot be
identified.

Only a few of the commonest macroscopic Foraminifera have been included.
In certain zones, where flint-meal is obtainable, many of the smaller forms
have been identified, but asMt has been impossible to obtain even a partially
complete zonal series, ii is considered wiser to leave them out altogether. The
same remark apvlies to the Ostracoda.

.Asteroidea are so rarely found in coast sections in a well-preserved state
that it is impossible to determine the species, or to give any idea of zonal
range.

February, 1900.] 26

3S8 DR. ARTHUR ROWE ON THE ZONES OF THE

Explanation of Plate VIII.

TerehratuHna rowei.

Figs. 1-5. — TerehratuHna rowei^ Kitchin.

Fig. I. — A specimen from the zone of AcHnocamax quadratus at East Harnhamf

Salisbury ; natural size, dorsal as|>ect (Blackmore Collection).
Figs. \a-d. — The same, enlarged ; four aspects.
Fig. 2. — A relatively broad example from the il/flrj«/i/«-band, east of Brighton ;

natural size (Rowe Collection).
Figs la-d. — The same, enlarged ; four aspects. Specimens having similar

form to this, with well-marked dorsal median anterior depression and

inflected frontal commissure, occur also in the zone of AcHnocamax

qucuiratus.
Fig. 3. — An individual, probably not fully grown, from the Jfarsupites-zonCy

Margate ; natural size (Rowe Collection).
Figs. ^a-d. — The same, enlarged ; four aspects. The nodose character of the

ribs is well shown.
Fig. 4. — A specimen from the Afarsu^iUs-ha,nd, east of Brighton ; natural

size (Rowe Collection).
Figs. 4/1, 6. — The same, enlarged.
Fig. 5. — An example from the Uiniacriuus-\xindy Seven Sisters Head (Sussex);

natural size (Rowe Collection).
Figs. Sa-d. — The same, enlarged.

BourgueHcn'nus.

Fig. 6. — A small, but well preserved, nipple-shaped head of BourgueHcrinns^

from the Afarsupites-hsind^ Margate (Rowe Collection).
Fig 6a. — A large example of the same from the Uiniacrinus-band^ Pegwell

(Rowe Collection).
Fig. 7. — A large barrel shaped ossicle of BourgueHcrinus, from the Afarsupites-

band, Brighton (Rowe Collection).
Fig. 8. — t^ourgueHcrinus elHpHcus^ with characteristic head, and barrel-shaped

ossicles, from the Micraster cor-angumum-zoxx^^ North Foreland,

Thanet (Rowe Collection).
Fig. 9. — \ long ossicle, not uncommon in the zone of Micraster cor-anguinum^

North Foreland, Thanet (Rowe Collection).
Fig. 10. — Bourgueticrinus ellipticus^ the characteristic head, from Fast Ham-
ham, Salisbury ; well up in the zone of Actinocamax quafratus

(Blackmore Collection).
Fig. \oa. — The same from Paulsgrove, Portsdown Hills, near the base of the

Actinocamax quadrat us-zone (Rowe Collection).
Fig. IO/5. —The same from extreme base of the Actinocamax quadratus-zone^

Sussex Coast (Rowe Collection).
Fig. i I . — Small dumb-bell-shaped ossicle from the Actinocamax quadratus-zont^

Sussex Coast (Rowe Collection).
Fig. lla. — The characteristic ossicle from the Actinocamax quadratus-zone.

The small one is merely an exaggeration of this form. Sussex

Coast (Rowe Collection).

Figures 6 — na natural size.

Proc.CeolAsscx;

Vcl-XVl.'Pl2LLe\ulI.

5«.

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WHITE CHALK OF THE ENGLISH COAST.

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368 ZONES OF THE WHITE CHALK OF THE ENGLISH COAST.

NOTES ON THE CLIFF SECTIONS.

By C. Davies Sherborn.

The sections here reproduced, show the various zones of the
White Chalk as they are seen on the cliff-face by the observer,
without regard to any dip that may exist landwards or seawards.
They are also given without any regard to the various bluffs that
exist and break the continuity of the general direction.

In Section i (Brighton to Eastbourne) the 1 1 miles omitted, near
Portobello, show practically no features of interest, and the first
important bluff we meet with is at the west corner of Friar's Bay,
while the second is at Old Nore Point. The small exposure
mentioned at p. 335, as between Seaford and Newhaven, is not
shown. Further Point occurs just about the letter " a " in Seaford
Head, and from there into Eastbourne there is but one note-
worthy bluff in the cliff-face, and that occurs just to the east of
Beltout.

In Section 2 (Dover to Kingsdown) a good east and weit
face will be found at Ness Point, St. Margaret's, and further
information as to dip can be gained at LeaUier Court Point, to
the north.

In Seciion 3 the upper section runs from west to east at first,
and afterwards, from the omitted four miles to the North Fore-
land, from south to north. In the lower section from the North
Foreland to White Ness, the general direction is south to north,
and the rest, generally, east to west. At White Ness, from the
letter " U " to the Point, the section is at right angles to that seen in
the cliff-face at the Lifeboat slip, while at the Target and at
several places between Margate and Gore End, similar faces can
be seen and studied.

Plate IX.

8.E.

Ne\

Tertiary beds

fG THE Cliff-Face from Brighton to Eastbourne.

H.sub. Hoiasier subgiohosus-ion^ (Chalk Marl,
Chloritic Marl, and Upper Greensand arc
visible on the shore).

B. Bryozoan bed in the Aciinocamax quadratuS'
ne, zone.

D, Stairway to Telscombe.

A ^ Ammonites (Jeptophylius group).

G. Groynes.

S. Sewer near Portobello.

'b 3 inches s= i mile ; vertical scale indicated.

3^9

THE NATURAL HISTORY OF PHOSPHATIC
DEPOSITS.

By J. J. H. TEALL, M.A., F.R.S.
(Presidential AtUress delir'erei February in'iy tgoo.)

GREAT interest centres round the element phosphorus in
consequence of the part it plays in the organic world, not
only as an important constituent of the hard parts of many
animals and of the seeds of plants, but also as forming an
essential component of living matter. From the earliest appear-
ance of life upon the globe down to the present day, there has
been a constant circulation of phosphorus between organic and
inorganic nature. From the rocks, in which it is almost always
present, though in small quantities, it passes into the soil and into
the waters of rivers, lakes, and seas. It is taken up by plants,
handed on to animals, and from these it may again pass either
directly or indirectly to the solid crust. I ask your attention to
the processes involved in this circulation, and to some of the
geological consequences which follow from it.

Phosphates of Igneous Rocks and Mineral Veins.

Of the various phosphatic minerals apatite is by far the most
abundant, and has long been recognised as the principal source
of the phosphorus found in the sedimentary rocks and in the
organic world. It occurs as definite crystals, less frequently as
more or less rounded grains, in all varieties of igneous rocks ;
but is more common in the basic than in the acid varieties.

Among the British rocks, exceptionally rich in apatite, may be
mentioned the mica-traps of the West of England and the
Southern Uplands of Scotland ; also a peculiar group of horn-
blende-diabases occurring at Wearde, Ernsettle, and other places
in the Plymouth district. The largest apatites I have ever seen
in normal igneous rocks occur in hornblende- and mica-ande-
sites from Bail Hill, near Sanquhar. One of these measures
5 X 2| mm., and is considerably larger than the porphyritic
felspars occurring in the same rock.

The apatites of igneous rocks have undoubtedly crystallised
out of the magma. They occur as inclusions in all the essential
minerals, and therefore belong to the earliest phases of con-
solidation. Under these circumstances it is somewhat surprising
that, so far as I am aware, apatite has never been produced
synthetically by crystallisation from artificial rock-magmas. It
has, however, been observed in lead slags by Mr. Hutchings **** and
Professor Vogt.'*-'

Pkoc. Geol. Assoc, Vol. XVI, Part 7, May, 1900.] 28

372 J. J. H. TEALL ON

been forced upwards along the cracks in the already consolidated
upper psLTt of the magma, or along the planes of least resistance
in the surrounding rocks, either in the form of a solution or, more
probably, as a dense gaseous substance at a temperature about its
critical point and therefore under great pressure. Professor Vogt's
theory of the origin of the apatite-veins by a kind of high
pressure solfataric (pneumatolytic) action may at least be regarded
as a useful working hypothesis. It is an expansion of the ideas
formulated by the illustrious author of " !^tudes Synth^tiques dc
Geologic Exp^rimentale."

Modern Deposits.

The apatites of igneous rocks and mineral veins are doubtless
the principal source of the phosphorus of the sedimentary rocks,
and of the organic world, for the other phosphatic minerals of
similar origin (monazite, xenotime, etc.) are too rare to have
sensibly affected the supply. That they pass into solution is
proved by their absence, or extreme rarity in the finer-grained
sedimentary rocks which contain zircons in abundance. These
two minerals occur together in igneous rocks, but the former is
much more common than the latter. If the apatites were not
destroyed in the process of denudation they would certainly be
found in fine-grained sands, such as those of Hampstead Heath,
in much greater abundance than zircon. But as Mr. Dick has
pointed out they are extremely rare, and occur only as inclusions
in other minerals.

The solution of apatite may be effected by water charged with
carbonic acid ; more readily by water containing organic acids or
ammonium carbonate. Phosphorus is, therefore, present in river
and sea waters ; but only in small quantities. The water of the
Rhine at Cologne contains rather less than one part in 1,000,000
(estimated as PoOr,) ; that of the North Sea, off the coast of
Norway, about ten times as much.^^* Nevertheless, it is from these
very small quantities that organisms living in the water must
obtain their supply of phosphorus.

If we leave out of account the very small amount of detrital
apatite it is highly probable that the whole of the phosphorus
found in the sedimentary rocks has been derived, either directly
or indirectly, from the waters of rivers, lakes, and seas by the
action of organic life.*

The once celebrated Peruvian guano furnishes an example of
the formation of phosphates by the accumulation of animal
remains. It was, for little now remains, an unsavoury mass made
up of the excrement of sea-birds mixed with their carcasses, and

• Calcium phosphate may be dep>osited directly from soUiiions of apatite in regions
where this mineral forms an important constituent of mineral veins ; e.g., stafTellitc in
association with the Norwegian veins. Hut this scarcely requires a modification of the above
st.itement.

WHITE CHALK OF THE ENGLISH COAST.

367

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374 J J- H. TEALL ON

per cent, of other calcareous organisms, 6 per cent, of siliceous
organic remains, including pale green casts of foraminifera, and
40 per cent, of coarse sediment ('35 mm ), including quartz, felspar,
garnet, black mica, and hornblende. Small glauconitic concretions
containing phosphate of lime ivere present.

The next sounding, a little further south in 150 fathoms, also
brought up green sand. The constituents were generally similar
to the last, but there was a large proportion of calcareous
organisms, including teeth and fragments of fish bones. The
mineral particles were smaller ('2 mm.). The dredge contained
glauconitic concretions, from 2 to 6 mms. in diameter, and a good
many phosphatic concretions, some over i cm. in diameter.
There was also much amorphous matter, which gave off an
organic odour when heated on platinum foil ; the phosphatic
nodules were found to consist of grains of quartz and glauconite>
precisely similar to those occurring in the deposit, cemented by
brown amorphous phosphate of lime.

The two soundings above refe^ed to were on the edge of the
Agulhas bank, the next was in deep water (1,900 fathoms) about
100 miles south-east of the bank. The bottom was of globigerina
ooze. The mineral particles were much smaller both in size
(•12 mm.) and amount (3 per cent.). The dredge contained
many small phosphatic concretions (i to 4 cms.) enclosing
glauconite and foraminifera. These facts fully prove that
phosphatic concretions are being formed at present on the bed
of the sea, and that they are produced in such a way as to
cement together the deposits accumulating on the sea-floor at the
spot where the nodules are found.

Messrs. Murray and Renard point out, as a general result of
their researches, that deposits of phosphate and glauconite are
especially characteristic of the continental borders of the great
ocean-basins, and that the former occur in greatest abundance
where currents of different temperatures or different salinities
intermingle. More or less phosphate, generally less than i per
cent, is always present in globigerina ooze ; but it is only in
special localities, where a considerable destruction of pelagic
organisms may be expected to occur, that important accumulations
take place.

Another observation made by the Challenger furnishes
striking proof that the phosphate of lime separated by fishes and
other organisms is dissoU'ed in sea water. At one station in the
Pacific, the dredge brought up 1,500 sharks' teeth, besides an
immense number of small teeth which were not counted.
Although the skeleton of the shark is only partly calcified, it
contains a considerable amount of phosphate of lime. The
presence of such a large number of teeth, without hones, repre-
sents, therefore, the solution of a vast amount of phosphatic
matter.

the natural history of phosphatic deposits. 375

Palaeozoic Phosphates.

We pass on now to a review of the distribution of phosphates
in the sedimentary rocks.

These phosphates vary greatly in chemical composition, but
this variation is mainly due to a varying admixture of sedimentary
material, such as quartz, glauconite, tests of foraminifera, etc. When
allowance is made for this, there is seen to be great uniformity.
The substance is mainly a tricalcic phosphate. The distribution
of fluorine in the sedimentary phosphates has been made the
subject of a special research by M. Carnot,*-^' with the result
that it is usually found to be present in proportions not very
different from those of a fluor apatite. The phosphorite deposits
of the south-west of France form a notable exception to this rule,
as they contain little or no fluorine. The Florida phosphates, on
the other hand, often contain more fluorine than is necessary to
make apatite. M. Carnot associates the presence of fluorine with
the action of sea-water.

Under the microscope the phosphates are seen to be either
amorphous or fibro-crystalline. The latter variety takes on
stalagmitic, mammillary, and agate-like forms. The fibres give
straight extinction, and are positive.

At one time it was generally held that the lower Palaeozoic
rocks were deficient in phosphates. This view was successfully
combated by our lamented friend, Dr. Hicks, <"' in an important
paper, published in the Quarterly Journal of the Geological
Society for 1875, ^o which Mr. Hudleston contributed an
appendix. These authors prove that phosphate - secreting
organisms, such as trilobites, abounded in Cambrian times, and
that the rocks themselves are by no means deficient in phos-
phoric acid. The same number of the Quarterly Journal
contains a paper by Mr. Davis ^^^' on a remarkable bed of
phosphatic nodules at the top of the Bala limestone in North
Wales, which was then being worked, and to which Dr. Voelcker
had directed the attention of the British Association in 1864.

The earliest known phosphatic deposits are those which occur
in the Cambrian of Nuneaton (Warwickshire), New Brunswick,
and Sweden. The Nuneaton deposit occurs a few feet below the
Hyolithus-\\vs\t^\ont. Pebbles of quartz and slate lie in a matrix
containing glauconite, oxides of iron and manganese, and 14 per
cent, of phosphate of lime.*'^'' The New Brunswick deposit,
described by Mr. Matthews '-"'" consists of small round or oval
nodules, about one half inch in diameter, set in a sandy matrix
of glauconite and quartz. The nodules have always a trilobite-
test or a number of fragments near the centre. Under the micro-
scope they are seen to consist of amorphous phosphate containing
fragments of trilobites {Protolenus), spicules of sponges, and the
tests of protozoa resembling foraminifera. It is extremely inter-
esting to note at this very early period the association of nodular

37^ J. J. H. TEAIX ON

phosphates and glauconite under conditions that have been
reproduced throughout the entire series of geological formations
down to the present day.

Phosphatic deposits occur at many horizons in the Cambrian
and Ordovician rocks of Sweden. They have been carefuDy
studied and well described by Gunner Andersson.'^' The oldest
Lower Cambrian deposit belongs to the zone of TarrtlUUa lavigaia^
It is represented by a boulder of the basal conglomerate found oo
the island of Gotska Sandon. The matrix is composed of
glauconite and quartz cemented by calcite. Numerous small and
often fragmentary specimens of the characteristic fossil, filled with
compact phosphate, occur in the matrix together with pebbles
of granophyre and quartz, and nodules of phosphatic sandstone
and compact phosphorite. The quartz grains in the nodules are
smaller than those in the matrix. Andersson especially calls
attention to the last mentioned fact, which appears to be not
uncommon in phosphatic deposits of all ages.

The Middle and Upper Cambrian periods are represented in
Sweden by the lithologically monotonous black shales, usuaUy
known as alum-shales, containing beds and lenticles of bituminous
limestones. These alum-shales exhibit a rich series of palxonto-
logical zones which have been worked out in great detail by the
Swedish geologists. Here and there the regular succession of
bUck shales is broken by the occurrence of conglomeratic deposits
— I use Andersson's term, but I am by no means sure that
nodular deposits would not, in some cases, be more appropriate
— and this phenomenon is always associated with a br&dc in the
faunal sequence. Moreover, the matrix of these conglomerates
contains a mixture of faunas due, in part at least, to the wearing
away of older deposits by submarine erosion.

One of the most interesting of the conglomeratic deposits is
termed the Acrothtle granulata-conglomeizie. It occurs between
the zones of Paradoxides Olandicus and P. tessini in the island of
Oland. The matrix is composed of grains of quartz and glau-
conite cemented with calcite. Fragments of trilobites and other
fossils occur. Acrothele granulata is abundant, and the two valves
are generally found together. The conglomerate contains green
coated pebbles of limestone apparently due to the destruction
of an older deposit, but as Acrothele granulata occurs in these
pebbles it cannot have been much older. Phosphates are present
as nodules or pebbles, and also, to a certain extent, as the infilling
material of the fossils in the matrix — a fact which proves that
the formation of the phosphate was contemporaneous with the
deposit.

Another and different mode of occurrence of phosphate is to
be found at the junction of the Cambrian and Lower Silurian
(Ordovician) in Nerike and Westergothland. The surface of the
Cambrian limestone has been worn into pits and depressions as if

THE NATURAL HISTORY OF PHOSPHATIC DEPOSITS. 377

corroded by chemical action. The overiying Lower Silurian
deposit is a limestone rich in glauconite containing phosphatic
fragments. It descends into the hollows of the underlying floor.
Corrosion phenomena are not limited to the surface of the
Cambrian limestone. They occur in the phosphatic bed, and in
overlying limestone ; but at these higher horizons they are more
tube-like and may be due to boring organisms. The phosphatic
fragments are merely detached portions of the underlying floor
in which the original carbonic acid has been replaced by phos-
phoric acid. Lower Silurian fossils occur in the matrix ; Cambnan
fossils in the fragments. In one case a thin crust of phosphate
was observed on the surface of the underlying limestone. Almost
everywhere in the Baltic region the Lower Silurian b^ns with
glauconitic deposits which contain phosphates, especially where
there are important breaks in the zonal succession.

Andersson recognises two types of phosphatic deposit in the
lower Pakeozoic rocks of Sweden. One, the conglomeratic, he
regards as a littoral facies ; the other, represented by the deposit
at the base of the Ordovician in Nerike, as a shallow sea facies.
The nodules and pebbles of the conglomeratic deposits consist
of phosphatic sandstone or compact phosphorite — sometimes also
of foreign rocks, such as quartz and granophyre. The phosphatic
nodules have probably been formed by some kind of concretionary
action from water charged with phosphatic matter derived from
brachiopoda, such as Acrotfuie 2J^d Oholus^ which secrete phosphate
of lime in their tests.

The fact that the sand-grains in the nodules are, as a rule,
smaller than those of the matrix of the conglomeratic beds
suggests that the concretionary action did not take pUce under
the conditions which finally prevailed ; but it is not necessary to
suppose that the nodules were washed into the littoral zone
from an area of deeper water, as our author suggests. This fact
might be explained by a shallowing of the sea or by an increase
in current action and the consequent winnowing away of the finer
matrix in which the nodules were originally formed.

In the case of the deposits at the base of the Lower Silurian
in Nerike and Westergothland, little or no concretionary action
has taken place. The phosphates are merely portions of the
underlying limestones in which a substitution of phosphoric for
carbonic acid has taken place.

I have referred to this important work by Andersson at some
length because it is based on a careful study of the stratigraphical,
palaeontological, and petrographical characters of the deposits.
It is only by a combination of the^e various methods of research
that we can hope to work out the natural history of our sedimen-
tar)' rocks ; a branch of research which I recommend to any of the
younger members of the Association who are looking out for work
to do.

378 J. J. H. TEALL ON

Phosphatic deposits of Lower Silurian age have recently (1S96)
been discovered in Tennessee, and have suddenly become of
considerable commercial importance. ''^ The Capitol limestone,
a *' granular current-formed and hence laminar limestone, showing
cross-stratification" has been locally phosphatised and subsequently
enriched by the leaching out of the more soluble carbonate. At
what date and under what conditions the phosphatisation tock
place has not been ascertained.

The Upper Palaeozoic rocks of this country are not known to
contain any important phosphatic horizons ; but this is merely a
local character, for in Tennessee deposits of great interest and
some commercial importance occur in the Devonian. These
deposits have been described by Mr. Hayes. ^^ They were worked
for a few years, but have now been almost entirely abandoned for
the more profitable Silurian phosphates above referred ta

At the western margin of the great Silurian inlier, which
forms such a striking feature on the geological map of the State,
the Devonian " period is represented by only 10 or 12 ft. oif
strata, intercalated between the Silurian limestone below and the
Carboniferous shales and limestones above.

Several feet of black carbonaceous shale, representing the edge
of the Chatanooga black shale, a well marked Devonian horizon,
traceable over about 40,000 square miles and attaining a thickness
of several hundred feet in Virginia, separate two phosphatic
horizons. The lower is formed of a bedded phosphate, the upper
is a nodular deposit containing glauconite —the faithfiil companion
of phosphate in all geological formations from the Cambrian
period to the present day.

The bedded phosphates are the most valuable, the richest
portion yielding from 70 to 80 per cent, of tricalcic phosphate.
Four varieties are described by Hayes under the terms oolitic,
compact, conglomeratic and shaly. Speaking of the oolitic variety
he says :

" On close examination of the unweathered rock the constituent
grains are seen to be small, round or flattened ovules, giving it an
oolitic structure. The ovules are bluish black or grey with a
glazed surface. Associated with them are many fragmentary casts
of very small coiled shells, generally well rounded and with the
same glazed surface as the ovules, so that they add to the
appearance of oolitic structure. These ovules and casts are
embedded in a fine grained or structureless matrix." Under the
microscope the ovules and fossil casts are seen to be composed of
a light amber or yellowish brown, amorphous phosphate of lime.
In addition to the casts of shells there are numerous fragments of
corals, and perhaps other organisms, all well rounded. It is
clear from the description given by Mr. Hayes that this deposit
has many points of resemblance to the phosphatic chalks and to
the Tertiary phosphates of Tunis and Algeria.

THE NATURAL HISTORY OF PHOSPHATIC DEPOSITS. 379

The ChaULDOoga black shale separates the bedded phos(^tes
from the Doduhu- layer at the base of the Carboniferous, which is
traceable as a phos^^dc and glauconitic horizon over an enormous
area, occurring in Eastern Tennessee, Middle Tennessee, and
Arkansas. ''The nodules vary in size and shape from nearly
spherical bodies, i to i| inches in diameter, to irr^^lar flattened
ellipsoids sometimes 2* fL in length, and a third or a quarter
as thick. They have smooth surfrtces, separating readily from the
enclosing matrix, and show no external evidence of organic origin.
. . . Thin sections of the nodules examined under the micro-
scope show them to be composed chiefly of an amber-coloured
amorphous substance with grains of pjrite and carbonaceous
matter, and in some cases showing a concretionary structure
consistii^ of very minute, radial, globular, and mammillary forms.''

Phosphatic nodules are not limited to the well>marked layer
at the top of the black shale, but occur on certain horizons in the
shale itself, thus remindii^ one ver>* forcibly of the relation which
the Cambridge Greensand bears to the GaulL

These Devonian rocks of Tennessee furnish a striking case of
the association of phosphates with areas of minimum sedi-
mentation, accompanied in all probability, in the case of the
nodular band, with a certain amount of submarine erosion.
Traced towards the north-east into the folded zone of the
Appalachians, the Devonian sediments swell out into an important
formation, measuring hundreds and even thousands of feet in
thickness.

Mlsozoic Phosphates.

The phosphatic deposits of the Mesozoic period are too
numerous to mention in detail. Phosphates are present in the
Rhaetic bone-bed. Nodules and phosphatised fossils occur in
the three important argillaceous deposits belonging to the Jurassic
period, the Lias, Oxford and Kimeridge Clays.

The Lx)wer Lias, north of the Mendip Hills, about Radstock,
furnishes an interesting case of the occurrence of phosphatic
nodules in an area of minimum sedimentation. Mr. Tawney^"*
proved that several ammonite-zones are here crowded tc^ether
into a small thickness. The deposition of sediment acts on the
zonal succession and on the distribution of phosphatic matter
very much as a prism acts on the rays of light. It supplies a
kind of dispersive power. When this is slight the zonal forms
are crowded together, and the phosphates, which would otherwise
be scattered through a considerable thickness of sediment, become
locally concentrated.

A bed of nodules is recorded by Mr. H. B. Woodwrard '*^' in
the Middle Lias of Lincolnshire, and another occurs near the
base of the Inferior Oolite (Dogger) in Yorkshire.

380 J. J. H. TEALL ON

On the Continent phosphatic nodules have been recognised in
the Upper, Middle, and Lower Lias of Lorraine. The most
important deposits occur approximately on the same horizon as
that at which phosphates are found at Radstock. The nodules
have been microscopically examined by M. Bleicher,^^ who has
proved that many, especially those of the Lower Lias, have been
formed by the accumulation of phosphatic matter round sponges.
They are similar to the phosphatised sponges from the Cambridge
Greensand described by Prof. Sollas.

Phosphatic nodules probably occur in the Oxford Clay of this
country, but I am not able to give actual instances. Mr. Newton
and I have, however, described their occurrence, on this horizon,
in Franz Josef land, from the collections made by Dr. Koettlitz
during his stay there as a member of the Jackson-Harmsworth
expedition. We have pointed out that some of these nodules are
largely composed of minute oval bodies similar in form and size
to the coprolites observed by Messrs. Strahan, Renard, and
Cornet in the phosphatic chalks of England, France, and
Belgium. I have since found similar bodies in a large coprolite
(32 ^ ^2 inches) with spiral groove, collected by myself many
years ago from the nodular bed at the base of the Red Crag in
Suffolk. This curious occurrence of coprolites within a coprolite
may possibly be explained by supposing a large animal to have
eaten smaller ones.*

The Kimeridge Clay also contains phosphatic concretions, and
a fairly persistent bed occurs at its base in Lincolnshire and Cam-
bridgeshire, marking the junction with the underlying Ampthill
Clay.<^'

Next in order come the nodular deposits of the Belemnites
iateraiiS'Zor\Q of Lincolnshire and Yorkshire, described by Mr.
lamplugh.^^' ^' These include the bed at the base of the
Spilsby Sandstone in Lincolnshire, that at the base of the Speeton
Clay in Yorkshire, and the interesting compound nodular band in
the middle of the Speeton Clay at the top of the B, iateralis-zouQ,
where a remarkable change of fauna takes place, due, in part at
least, to the intermingling of northern and southern forms.

The records of the Cretaceous period contain still more
important nodular deposits. There are, for example, the deposits
of Wicken, Potton, and Brickhill, of Lower (ireensand age,
described by Brodie, Walker, Seeley, Keeping,'^-' myself,*^' and
others ; and the remarkable Cambridge Greensand so well studied
by Seeley, Fisher, <^^' Sollas, ^^* and Jukes-Browne.<-^' Nodules also
occur in the Gault and in the Chalk. A well-marked bed is

• Since this was written Mr. Allen has directed my attention to a paper by Dr. Rust, in
which similar oval bodies are describetl as occurring in certain coprohtes from the Gault
(Paltrpntographica, Band xxxiv, 1887-1888, p. 184). Dr. Rust considers that two ex-
planations are possible. The oval lx)dies may be either the coprolites of small animals which
have been eaten by the large animal, or the casts of the follicles of the intestines of the
larger animal.

THE NATURAL HISTORY OF PHOSPHATIC DEPOSITS. 38 1

found in the Ammonites mammillatus-zQx\^ at West Dereham in
Norfolk, and Folkestone in Kent. This is one of the most widely-
distributed phosphatic horizons in Europe, for it is traceable all
round the northern part of the Paris basin, and is found also in
the basin of the Rhone.*'''

I will not attempt to give an account of these various deposits,
but content myself with some general remarks on the phosphatic
nodules and the conditions under which they were probably
formed. The " nodules " — I use the term in a broad and general
sense — include :

(i) Casts of fossils, such as cephalopods, lamellibranchs,
gasteropods, brachiopods, echinoderms, etc.

(2) Phosphatised sponges and pieces of wood.

(3) Concretionary masses.

(4) Well-rounded or sub-angular pebbles of phosphatic sand-
stone and compact phosphate.

(5) Bones, teeth, and occasionally coprolites of fish and
snurians.

The nodules are mainly composed of phosphate of lime with
only small quantities of phosphate of alumina and iron. They
invariably contain more or less of the sediment which was accu-
mulating on the sea-bed at the time of, or shortly before, their
formation. This sediment may be a quartzose sand, a glauconitic
sand, a loam, clay, marl, or organic ooze. It may or may not
agree in composition with the matrix in which the nodules are
embedded. Not unfrequently the sand-grains in the nodules are
smaller than those in the matrix, and different nodules in the
same bed may contain sediment of different types. Thus the
nodules of the Potton deposit, so far as I have examined them,
contain smaller grains than the matrix ; those of the West Dere-
ham deposit, on the other hand, contain grains of the same size as
the matrix, and are, in part at least, merely phosphatic concretions
in the sand.*^'

The shapes of the nodules have been determined by many
causes ; by the form of the original concretion, by that of the
organism of which the nodule is a cast, or around which the
phosphate has accumulated, and lastly by chemical corrosion or
mechanical attrition. Boring organisms have also affected the
forms of many nodules, a fact which clearly proves that they must
have lain exposed on the sea-floor.

Mr. I^amplugh has called attention to the complex character
of the nodules from the bed which occurs in the middle of the
Speeton Clay. Fragmentary casts of ammonites in black phos-
phate are often encrusted with a brownish phosphate containing
grains of quartz and glauconite. Both types of phosphate are
sometimes enclosed in a grey limestone which seems also to
have had a concretionary origin. All these facts point to the

382 . J. J. H. TEALL ON

conclusion that the nodule-beds represent a considerable period
of time.

Much discussion has taken place as to the nature of the
fossils occurring in the Cretaceous phosphatic nodules. Are
they indigenous or derived ? I do not propose to enter into this
discussion, but I will point out that most of the so-called derived
fossils belong to the age of the missing zones. This has been
conclusively established by Mr. Jukes-Browne for the Cambridge
Greensand, and by Mr. Lamplugh for the two coprolite beds at
Speeton, and for the bed at the base of the Spilsby Sandstone.

A more careful determination of the species of other deposits
will, as Mr. Lamplugh maintains, probably strengthen this con-
clusion. Thus, in my paper on the Potton and Wicken
phosphatic deposits, I called attention to the extraordinary
abundance of rolled casts of Ammonites biplex^ which I r^arded
as having been washed out of the Kimeridge Clay.

Mr. Lamplugh assures me that, at any rate, the majority of
the ammonites in question are not A, bipiex. Sow., but a form of
OUostephanuSy characteristic of the missing beds, and unknown in
the Kimeridge Clay. This I am quite prepared to accept, and
in support of it I may mention that the casts of this ammonite
are formed of phosphatic sandstone which would not be the
case if they had been derived from the Kimeridge Clay as I
supposed.

Everything points to the conclusion that the nodule beds
represent long periods of time, and that they occur in areas of
minimum sedimentation, or where sediment once formed has been
subsequently removed by submarine erosion, probably not long
after its accumulation.

But the Cretaceous phosphates do not always occur in the
form of detached nodules or as nodular and more or less con-
glomeratic deposits. There are the remarkable phosphatic chalks
of Taplow ^'^ and Lewes ^ described by Mr. Strahan, and the
corresponding deposits of France which have engaged the
attention of Messrs. Lasne,^ de Mercey,^*^' Cornet, Renard,"* and
Cayeux.^' They consist of brown phosphatic grains, made up of
more or less phosphatised foraminifera and prisms of hioceramus^
together with fragments of the bones, teeth, scales, and coprolites
of small animals. The matrix is a fine calcareous powder largely
composed of coccoliths, discoliths, and rhabdoliths. That the
phosphatisation is not later than the deposit is proved by the fact
that the matrix is calcareous.

The origin of the phosphatic matter has given rise to some
discussion. M. de Mercey regards it as having come up from
below, M. Lasne attributes it to the influx of rivers bringing down
apatite in solution, Messrs. Renard, Comet, and Strahan, suppose
it to have been derived from the organisms of which such
abundant traces occur in the deposit. In England I imagine we

THE NATCRAL HISTORY OF FHOSPHATIC DEPOSITS, 383

shall all accept the last mentioned Tiew, notwithstandii^ the hc^
pointed out by NL Lasne, that the substance is a fluo-phosphate
practically agreeing with apatite in composition.

Caixozoic Phosphates.

The phosphatic d^XKits of Cainozoic age remain to be con
sidered. They are the most important from a commercial point
of view, for they include the enormous deposits of South
Carolina. Florida, Algeria, and Tunis. In this country they are
feebly represented by the interesting conglomeratic bed at the
base of the Crag, particulars of which together with full references
to the extensive literature will be found in Mr. Reid's GtologUal
Survey Memoir on the Pliocene,'^' The curious box-stones con-
taining a Pliocene fauna somewhat older than the Crag deserve
more than a passing notice. They are nodules of brown phosphatic
sandstone, which usually contain hollow moulds of Pechituulus or
other calcareous shells.

The origin of nodules of this kind has been satisfactorily ex-
plained by Dr. Herman Credner.'** In Suffolk they are evidently
remanie, but in the Oligocene of Saxony precisely similar nodules
occur in place. There the phosphatic matter, mainly phosphate
of lime, has been concentrated round calcareous shells and fish
remains ; but the shells have entirely disappeared as in the box-
stones of the Crag, and the fish are represented only by the
denser and more insoluble portions of their skeletons and by their
teeth and scales. Most of the bones have disappeared. As Dr.
Credner points out, carbonic acid and anmionia are formed in
connection with the decomposition of animal matter. Phosphate
of lime is soluble in water charged with carbonic acid, and still
more so in water containing ammonium carbonate. A solution of
ammonium phosphate is thus formed at the expense of the fish
bones, and one of calcium carbonate at the expense of the shells.
The shells and the fish embedded in the porous sand thus become
surrounded by water highly charged, in the one case with calcium
carbonate, in the other with ammonium phosphate. When these
two solutions react there is a precipitation of calcium phosphate
together with some carbonate, and in this way the loose sand
becomes cemented into a hard nodule enclosing, in the one case,
a hollow mould of a shell, and in the other case, the more insoluble
portions of the fish. The forms of the nodules, their microscopic
structure and chemical composition, are all in accordance with the
theory, which has been still further strengthened by experiments
proving the solubility of fish-bones in a solution of ammonium-
carbonate, and the precipitation of calcium phosphate on the
addition of a saturated solution of calcium bicarbonate.

In some such way the box-stones in the Crag must have been

384 J. J. H. TEALL ON

formed in an early Pliocene deposit of which they are now the
sole survivors. The chemical reactions to which Dr. Credner has
called attention have doubtless played an important part in the
formation of many other phosphatic concretions.

Phosphates occur in greater or less abundance in many
Tertiary deposits, the most important being those of Algeria,
Tunis, South Carolina, and Florida. The richest deposits of
North Africa occur near the base of the Tertiary Series, associated
with marls and limestones. They contain bones and teeth of
fishes and reptiles, often of considerable size and in great
abundance. ^ Apart from this they have a general resemblance
to phosphatic chalks. The matrix in which the larger constituents
are embedded is made up of brown phosphatic grains, grains of
glauconite, a few of quartz, and a calcareous paste. The phos-
phate occurs as more or less spherical grains, reminding one, as
regards form and size, of oolitic grains. I have not been able to
recognise with certainty either foraminiferal casts or small
coprolites in the specimens I have examined from Djebel Kouif
(Algeria), but they have been described as occurring in the
corresponding rocks from Tunis.*"' The calcareous paste is
composed of minute idiomorphic rhombs of calcite.

These phosphatic limestones have been traced over wide areas
in Tunis and Algeria. The individual beds vary in thickness
from a few centimetres to three metres, and the richest contain
over 60 per cent, of tricalcic phosphate.

The Tertiary phosphatic deposits of North America are of
Pliocene — possibly in some cases of Pleistocene age. They are
found at intervals all along the Atlantic coast from Virginia to the
extremity of Florida, and it is interesting to note that phosphatic
concretions are now forming in the sea off the same coast. The
well-known deposit of South Carolina '*' consists of irregularly
shaped nodules which are sometimes cemented together so as to
form masses weighing a ton or more. Associated with the nodules
are " many sharks* teeth and cetacean bones, as well as the
remains of the mastodon, megatherium, elephant, deer, horse, cow,
hog, musk-rat, and other land animals " The matrix may be
either sand or clay. The deposit rests on sands or marls, the
latter containing from 55 to 95 per cent, of calcium carbonate.
It is covered by Quaternary sands, clays, or marls. Many of the
nodules are phosphatised portions of the underlying marl con-
taining Miocene fossils.*^^' The bones of land animals are never
found embedded in the phosphate. The nodules are often more
or less rounded, and bored by marine organisms. They contain
from 25 to 70 per cent, of calcium phosphate.

Apart from its exceptional richness, the South Carolina deposit
reminds one very much of that at the base of our own Crag. The
Florida deposits are of a somewhat different character. The "rock
phosphates " are phosphatised portions of the underlying Eocene

THE NATURAL HISTORY OF PHOSPHATIC DEPOSITS. 385

and Miocene limestones. Sometimes the phosphatisation has
taken place without serious disturbance of the beds, but more
frequently the component materials lie in the utmost confusion.
Irregularly shaped boulders of all sizes up to lo ft in diameter
lie in a matrix of soft phosphate or of clay and sand. In addition
to the " rock-phosphates " there are, according to Dr. Dall, also
pebble phosphates of Pliocene age. The latter rest uncomformably
on Eocene and Miocene rocks, and give therefore some clue to
the age of the phosphatisation.

\yh2Lt was the nature of the phosphatising agent? The
descriptions by Eldridge,'"' Wyatt,'** and others do not mention
any facts pointing to submarine action. It was in all probability,
as Darton '" supposes, due to guano-deposits and therefore a
surface phenomenon.

We have now passed in review illustrations of the principal
types of deposits. Calcium phosphate may be formed by the
accumulation of animal remains, by the replacement of carbonic
by phosphoric acid through the action of solutions arising from
the leaching of guanos, or the decomposition of animal matter,
by direct deposition from solutions of calcium phosphate and by
chemical precipitation, due to the interaction of solutions containing
ammonium phosphate and calcium bicarbonate.

Deposits containing both calcium phosphate and calcium
carbonate, such as the phosphatic chalks, may be enriched by the
action of water charged with carbonic acid, owing to the
comparative insolubilit>' of the former.

The formation of phosphatic deposits may take place on the
surface of the land, or beneath the waters of the ocean. In the
latter case they appear to be limited to continental borders
where deposition is slight, and where current action is often well
marked.

From the earliest time down to the present day the physical
and chemical conditions under which phosphatic deposits have
been formed have remained essentially the same.

My duties as your President are at an end. I thank you
most heartily for the honour you conferred upon me in electing
me to the post, and I assure you that I shall carry away the
most pleasant recollections of my two years of office. I desire
also to thank the Officers with whom it has been a pleasure to
serve, and to whose enthusiasm and ability the continued prosperity
of the Association is so largely due.

My successor needs no introduction. He is not only a
distinguished geologist, but also an old and tried friend of the
Association, and we are all delighted that he has consented to act
as our President I have now great pleasure, mingled with regret
that ray own term of office is over, in asking Mr. Whitaker,
President of the Geological Society, to take the Chair.
Pkoc. Geol Aisc:., Vol. .XVI. Part 7, Mav, 19CX).] 29

386 NATURAL HISTORY OF PHOSPHATIC DEPOSITS.

LITERATURE REFERRED TO IN THE TEXT.

1. Andersson, J. G. — " Ueber cambrische und silurische phosphorit fiihrende

Gesteine aus Schweden. Bull. Geol. Inst, Upsala, vol. ii, p#rt 2
(1896), p. 133.

2. Blayac, J. — "Description geologique de la region des phosphates du

Dyr et du Kouil.'* Ann. des Mines, scr. 9, T. vi, p. 319.

3. Bleicher, M. — "Sur le gisement et la structure des nodules phosphates

du Lias de Lorraine." Bull. Sbc. Geol, France, 1892, p. 237.

4. Brown, L. P. — " The phosphate rock deposits of TennefSee." XlXtk

Ann, Rep. U.S. Geol, Survey (1898), p. 547.

5. Carnot, a. — "Sur les variations observees dans la composition des

apatites, des phosphorites, et des phosphates sedimentaires.*' Ann,
des Miues^ T. x (1896), p. 137.

6. Cayeux, L. — "Note preliminaire sur la constitution des phosphates de

chaux suessoniens du sud de la Tunisie." Comptes Jiendus 123
(1896), p. 273. ^

7. ' . — "L'etude micrographique des* Terrains sedimentaires."

Lille, 1897.

8. Cornet and Renard. — " Recherches micrographiques sur la nature et

I'origine des roches phosphatees.** Bull. Acad. Roy, Belgique^ 3mc
ser., T. xxi (1891), p. 126.

9. Credner, H — Die Phosphorit-knollen des Leipziger Mitteloligocenc."

Abh. Kdnigl SdcA. Gesell. IViss, B. xxii (1895).

10. Dall, W. H. — " Note on the ' Land-phosphate ' of the Ashley River

District, South Carolina." Amer. Jour. Sci.y 3rd ser. vol. 48 (1894),
p. 300.

11. Darton, N. H. — "Notes on the Geology of the Florida Phosphatic

Deposits." Amer. Jour, Sci.^ 3rd ser., vol. xli (1891), pp. 102-105.

12. Dai'BREE, a. — "ifitudes synthetiques de Geologie Experimentale."

Paris, 1879, p. 48.

13. Davies, D. C. — "The Phosphorite Deposits of North Wales." Quart,

Journ. Geol Soc.y vol. xxxi (1875), p. 357.

14. Eldridge, G. II. — "A preliminary sketch of the phosphates of Florida."

Amer. Inst. Mining Eng.. vol. xxi (1892-93), pp. 1 96-23 1.

15. Fisher, O. — "On the Phosphatic Nodules of the Cretaceous rock of

Cambridgeshire." Quart. Journ. Geol. Soc.y vol. xxix, p. 52.

16. Gautier, Armand. — " Formation des phosphates naturels d'Aluraine

et de Fer." Comptes Rendus, Paris, vol. cxvi (1893).

17. Hayes, C. W.— "The Tennessee Phosphates." XVIIth Ann, Rep. U.S.

GeoL Survey (1896), p. 519.

18. IIiCKS, Dr. H. — "On the occurrence of phosphates in the Cambrian

rocks." Quart. Journ. Geol. Soc.^ vol. xxxi (1875), p. 368.

19. Hughes, G. — " On some West Indian Phosphates." Quart. Journ. Geol.

Soc., vol. xli (1885). p. 80.

20. HuTCHiNGS, W. M. — "On the occurrence of Apatite in Slags." Nature^

Sept. 15th, 1887.

21. Jukes-Browne, A. J. — "Relation of Cambridge Gault and Greensand."

Quart. Journ. Geol. Soc.^ vol. xxxi, p. 256.

22. Keeping, W. — "The Fossils of Upware and Brickhill." Cambridge,

1883.

23. Lamplugh, G. W. — "On the sub-divisions of the Speeton Clay."

Quart. Journ. Geol. Soc, vol. xlv (1889), p. 575.
24. . — "On the Speeton Series of Yorkshire and Lin-
colnshire." Quart. Jcurn. Geol, Soc. vol. lii (1896), p. 179.

25. Lapworth, Professor. — "A Sketch of the Geology of the Birmingham

District." Proc. Geol. Assoc., vol. xv (1898), p. 343.

26. Lasne, II. — '*Sur les terrains phosphates des environs de Doullens."

Bull. Soc, Geol, France, 3me ser., T. xviii, p. 441, and T. xx, p. 211.

PROCEEDINGS. 387

27. Mercy, X. de. — '* Remarques sur les gitcs de phosphate de chaux de la

Picardie." Bull, i^. Geol. France, 3me ser. T. xix, p 854.

28. Murray and Renard. — " Report on Deep Sea Deposits " {CkalUngtr

Expedition).

29. Matthews, W. D. — "On the phosphatic nodules of the Cambrian of

New Brunswick.'* Tran%. Sew. York Acad, of Sci,^ vol xii (1893),
p. 108.

30. Penrose, R. A. F. — ** Nature and origin of deposits of phosphate of

lime." Bull. U.S, Gtol. Survey ^ No. 46 (1888). This memoir con-
uins a very complete bibliography of the subject.

31. Reid, Clement. — "The Pliocene Deposits of Britain." Metm Geol,

Survey.

32. Roberts, T. — "The Upper Jurassic Clays of Lincolnshire." Qf^tirt,

Journ. GeoL Soc., vol. xlv (1889), p. 545.

33. Roth, J. — "Chcmische Geologie," vol. i, pp. 456, 505.

34. Safford, Prof J. M. — "Phosphate Deposits in Tennessee." Amer,

Geologist^ 1896.

35. SOLLAS, \V. J. — "On the Coprolites of the Upper Greensand.'* Q*utrt,

Journ. Geol. Scc.^ vol. xxix, pp. 63 and 76.

36. Strahan, a. — " On a phosphatic chalk with BelenmitelU quadrata at

Taplow." Quart. Journ, Geol. Soc.^ vol. xlvii, p. 356.

37, . — •* On a phosphatic chalk with Holaster planus at Lewes.**

Quart. Journ. GeoL Soc,^ vol. Hi, p. 463.

38. Tawney, E. B.— "Notes on the Lias in the neighbourhood of Radstock.'*

Proc. Bristol Nat, Soc,^ new ser., vol. i, pp. 167-189.

39. Teall, J. J. H. — "The Potton and Wicken phosphatic deposits."

Cambridge, 1875.

40. ■ — . — " On a phosphatised trachyte from Clipperton Atoll.**

Quart. Journ. Giol, Soc„ vol. liv (1898), p. 230.

41. Thomas, P. — "Gisements de phosphate de Chaux des Haut-plateax de

la Tunisie. Bull. Soc. Geol, France, 3me se., T. xix, p. 370.

42. Vogt, J. H. L. — "Mineralbildung in Schmelzmassen.** Kristiania, 1892,

p. 265.

43. . — "Die Apatit-Ganggruppe." Zeit, /, prakt, Geologte^

1895, pp. 367, 444 and 465.

44, Woodward, H. B. — "The Jurassic Rocks of Great Britain,** vol. iii,

Mem. GeoL Survey.

45. Wyatt, F. — " Phosphates of America." 1891.

ORDINARY MEETING.

Friday, February 2nd, 1900.

W. Whitaker, B.A., F.R.S., President, in the Chair.

George F. Brown and R. VV. Gray were elected Members of
the Association.

There being no further business the meeting then terminated.

ORDINARY MEETING.

Friday, March 2Nd, 1900.

W. Whitaker, B.A., F.R.S., President, in the Chair.

George Gibbens was elected a member of the Association.
A paper was read by Mr. F. A. Bather, M.A., F.G.S., on
" Wind-worn Pebbles in the British Isles."

388

ANNUAL GENERAL MEETING.

February 2nd, 1900.

J. J. H. Teall, M.A., F.R.S., President, in the Chair.

Messrs. F. Trickett and J. Sheer were appointed scrutineers of
the ballot.

The following Report of the Council for the year 1899 was
then read :

THE numerical strength of the Association on December
31st, 1899, was as follows :

Honorary Members .14

Ordinary Members :

a. Life Members (Compounded) . -157

b. Old Country Members (5s. Annual Subscription) 6
r. Other Members (los. Annual Subscription) . 390

Total .... 567

This shows a net increase of twenty-two as compared with the
corresponding figures for the previous year.

During the year fifty-seven new members were elected. The
Council regrets that the Association has lost two Honorary and
seven Ordinary Members by death — Dr. Henry Hicks, Sir William
Henry Flower, Charles Brongniart, George Dowker, John
Dovaston, Henry Ullyetl, C. N. Peal, James R. Gregory, and
N. E. Mclntire.

The loss of Dr. Henry Hicks will be deplored, not only by
members of the Association, but by geologists in general. A
native of St. David's, Pembrokeshire, he early devoted his
energies to unravelling the geological structure of that district,
afterwards extending his researches to other parts of the country.
His labours have thrown considerable light on the relations of
the older Palaeozoic and pre-Cambrian rocks, as well as the
Glacial and other Drift deposits. He was your President from
1883 to 1885, and always evinced a keen interest in the welfare
of the Association. Your Proceedings contain many valuable
papers from his pen, and his great experience as a field geologist
was always readily placed at the disposal of the Association.

Sir William Henry Flower had been an Honorary Member
of the Association since 1880. He will live in your memories
chiefly on account of the admirable way in which he organised
the rearrangement of ihe collections at the Natural History
Museum, South Kensington, of which he held the directorship
until less than a year before his death, when he was constrained
to relinquish the post on account of failing health.
Proc. Geol. Assoc., Vol. XVI., Part 7, May, iqcx).]

ANNUAL GENERAL MEETING.

389

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39^ ANNUAL GENERAL MEETING.

Charles Brongniart was elected a Member of the Association
in 1879, and an Honorary Member in 1896. He was one of the
few palaeontologists who have devoted themselves to the study of
the fossil insects, and will long be remembered for his masterly
researches on the Palaeozoic forms of that group.

In George Dowker the Association has lost an old and tried
Member. He joined the Association at its foundation in 1858,
and since then has at various times given valuable help in the
conduct of excursions. So lately as Easter, 1897, he conducted
an excursion to Romney Marsh, and contributed a paper to your
Proceedings on the Physical History of that district. Only a
few days before his death he read a paper on " Coast Erosion "
before the Geological Section of the British Association at
Dover.

John Dovaston was an accomplished naturalist and antiquary.
He was a direct descendant of John Dovaston, the well-known
antiquary of the eighteenth century. He will be remembered by
many members who have been in the habit of attending the long
excursions, and who will retain pleasing recollections of his kind
and genial character.

The income of the Association for 1899 was ;£29i 13s. 6d.,
the largest since 1887 ; and the expenditure was ;£266 3s. 6d.,
which included a sum of J^2\ i6s. 2d. due to the printers for
1898. Thus, while the expenditure remains normal, the income
has increased considerably, an increase due partly to the large
number of new members who joined during the year, and partly
to the unusually high receipts from the sales of Publications.
Having regard to the very satisfactory financial position of the
Association, your Council has thought fit to hand over to your
Trustees for investment a sum of ;£^5o, representing approximately
the composition fees received during 1898 and 1899. This
investment was carried out in January of this year, and resulted
in the purchase of ;^47 los. Nottingham Corporation Three per
Cent. Stock.

On June 8th, a fire occurred on the premises of the Associa-
tion's printers, which, unfortunately, caused considerable damage
to the stock of Publications stored there. Your Council particu-
larly regret that the remaining stock of the " Record of Excur-
sions " was destroyed.* As compensation for the loss incurred in
the fire the Commercial Union Assurance Company paid to your
Trustees a sum of ;;^i25, which has been invested by them in the
purchase of ;£'ii6 7s. 4d. Nottingham Corporation Three per
Cent. Stock. The Association were also allowed to keep the
salvage, and, so far as this has been fit for anything, it has been
offered for sale at a considerably reduced price.

Five numbers of the Proceedings, containing 260 pages of

* It has since been discovered that a few undamaged copies of the '* Record " rexmun
in stock.

ANNUAL GENERAL MEETING. 39 1

text, seven plates, and fifty-one other illustrations, have been
published during the year 1899. The thanks of the Association
are due to the authors for their contributions, especially to Dr.
Barrois for "A Sketch of the Geology of Central Brittany,"
published in the July number ; to Mr. H. H. Arnold- Bemrose for
" A Sketch of the Geology of the Lower Carboniferous Rocks of
Derbyshire," and for the excellent plates which illustrate the
August number; to Dr. Barrois, The Societe Geologique de
France, The Societe Geologique du Nord, and to the Geological
Society of London, for cliches and the loan of blocks used in
illustrating the Proceedings.

During the forty years' successful career of the Association,
many papers read at the meetings, especially in the earlier years,
were not published in the Proceedings, but several of them
were printed separately. Hitherto no collection of these has
been made for the Library. Fortunately, just before the fire
above alluded to, a collection of these papers was made, and it
was found possible to make two very nearly complete sets. They
have been bound, and one set has been placed in St. Martin's
Library, and the other, with a set of the Proceedings, is retained
at University College.

A sum of j£i 4s. was received from the late Amateur
Scientific Society, to be expended on the purchase of books for
the Library. This amount has been devoted towards the pur-
chase of Sir A. Geikie's ** Ancient Volcanoes of Great Britain."
Amongst other additions to the Library may be mentioned the
" Life of Sir J. Prestwich." The binding of the serials has been
continued.

The number of volumes borrowed by members has not been
very great, but considerable use of the books is made at the
Library, both by members and others, and this use is facilitated
by the card catalogue, which has recently been completed.

The following is a list of the papers read at the evening
meetings :

" The Natural History of Cordierite and its Associates," being the address
of the President, J. J. H. Teall, M.A., F.R.S.

"A Sketch of the Geology of Central Brittany," by Dr. Charles
Barrois.

" The Drainage of Cuestas," by Prof. W. M. Davis.

" The Pleistocene Deposits of the Ilford and Wanstead District," by
Martin A. C. Hinton.

" The Pleistocene Mollusca of Ilford," by A. S. Kennard and B. B.
Woodward, F.L.S., F.G.S.

" The Raised Beach and Rubble Drift at Aldrington, between Hove and
Portslade-by-Sea, Sussex, with Notes on the Microzoa," by FREDERICK
Chapman, A.L.S., F.R.M.S.

" A Sketch of the Geology of the Lower Carboniferous Rocks of Derby-
shire," by H. H. Arnold-Bemrose, M.A., F.G.S.

" The Zones of the White Chalk of the English Coast. I. Kent and
Sussex," by Dr. A. W. RoWE, F.G.S.

392

ANNUAL GENERAL MEETING.

Lectures were delivered by H. W. Monckton, F.L.S., F.G.S.,
on " The Glaciers and Fjords of the Bergen District, Norway '*' ;
and by G. W. Lamplugh, F.G.S., on " The Geology of the Isle
of Man."

Your thanks are due to all these gentlemen.

A Conversazione was held in November, and a full list of the
exhibits will be published in the Proceedings.* Your thanks are
due to the many members who contributed to the success of that
evening.

The following museums were visited in 1899 :

March nth. — Mr. Hudleston's Museum, 8, Sunhope Gardens, under the

direction of Prof. Blake« in the unavoidable absence of Mr. Hudleston.
September nth, — The Prehistoric Department of the British Museum,

Bloomsbury, under the direction of Mr. C. H. Read.
September nth. — The Museum of Practical Geology, 28, Jermyn Street, under

the direction of Sir Archibald Geikie, Mr. Teall (President of the

Association), and Mr. F. W. RuDLEK.
September nth. — The Geological Galleries of the Natural History Museum,

Cromwell Road, under the direction of Dr. Woodward and Mr. A.

Smith Woodward.
September nth.— On this date the President and Secretary and several

members of the Societe Beige de Geologic were of the party, and in the

evening were entertained by the Presidents of the Geological Society and

the Geologists* Association at the rooms of the Geological Society,

Burlington House.

The following is a list of excursions made during the past year.
Detailed reports will be found in Parts 3 and 5 of the Proceedings,
Vol. XVI.

Date.

Place.

March 31 to April Seaton, Sidmouth, Budleigh

4 (Easter) Salterton, and Exeter.

April 8 (Cycling) Winchfield to Wokingham.

April 15 Walton-on-the-Hill.

April "22
April 29
May 6
May 13
May 18 to 24

(Whitsuntide)
May 27 (Cycling)

June 3

Staines.

Weldon, Dene, and Gretton.

Thame District.

Ilford.

Brittany.

Bushey to Harrow.

Reigate.

" Vol. XVI, p. 286.

Directors.

Horace B. Woodward,

F.R.S , and W. A. E.

Ussher, F.G.S.
H. W. Monckton, F.L.S.,

F C S
W. * Whitaker, B.A.,

F R.S., Pres. G.S., and

W. P. D. Stebbing,

K C S
W. Whitaker, B.A.
Beeby Thompson, F.C.S.
A.M.Davies,B.Sc.,F.G.S.
T. V. Holmes, F.G.S.
Charles Barrois, D.Sc,

and P. Lebesconte.
Rev. Prof. J. F. Blake,

M.A.
Miss M. C. Crosfield,

and Rev. Ashington

Bullen, F.G.S.

ANNUAL GENERAL MEETING.

393

Date.

Place.

Directors.

June 10

Rickmansworthand Harcfield.

W. Whitaker, B.A., and
John Hopkinson.F.G.S.

June 17

Lichfield and Cannock.

Prof. C. Lapworth, LL.D.,
and ProLW.W. Watts,
xM.A.

June 24

Brighton and Rottingdean.

C. Davies Sherborn, and
Henry Edmonds, B.Sc.

July I

Cuxton and Durham.

G. E. Dibley, F.G.S.

July 8 (Cycling)

Chiltern Hills

H. J. Osborne White,
F.G.S.

July 15

Guildford and Godalming.

A. K. Coomara-Swamy,

p« /~> c *

W. p. b.'Stebbing, F.G.S.

July 22

Claygate, Chessington, and

Oxshotu
Derbyshire.

August 2 to 9

H . Arnold-Bemrose, M. A.,

(Long Excursion).

Wheelton Hind, M.D.,
and J. Barnes, F.G.S.

August 10

Nottingham.

G. E. Coke, F.G.S., and
Prof. Carr, M.A.

September 9

Charlton, Erith, and Crayford.

W. Whitaker, B.A.

Notwithstanding the exceptionally large number of excursions
the average attendance has been veiy good.

Your thanks are due to the Directors of the excursions, and
also to the following for assistance and hospitality :

Mr. and Mrs. Hudleston, at Stanhope Gardens ; Mr. Gilbert,
Mr. M. B. Duff, Mr. J. A. Sparks, and Mr. F. Gardner, at Staines;
Monsieur T. Bezier, Monsieur A. Michel Levy, and Monsieur
S. P. Oehlert, in Brittany ; Mr. Anthony Alsop, Mr. Henry
Fisher, and Mr. Wm. Hurst, in Derbyshire ; and Miss Crosfield,
at Reigate.

Your thanks are due to Sir Archibald Geikie, Director-General
of the Geological Survey, for the presentation of the following
sheets of the Geological Map of England and Wales : One inch,
Nos. 13, 22, 71 N.E., 72 N.E., and 81 N.W., and for the loan of
blocks from his " Ancient Volcanoes of Great Britain," and also
to Dr. Barrois for Sheets 59, 74, 75, and 89, of the Geological
Map of Brittany.

The management and arrangement of the excursions of the
Association during the past year have been in the hands of the
following committee : F. Meeson (chairman), Miss Foley, H. A.
Hinton, Bedford McNeill, A. E. Salter, W. P. D. Stebbing, and
A. C. Young. Your thanks are due to the members of this Com-
mittee for the trouble they have taken in arranging and carrying
out a very full excursion programme.

Mr. Frederick Meeson having signified his desire to retire
from the office of Excursion Secretary, the Council, on October
6th, accepted his resignation, and, acting under Rule XIV.,
appointed Mr. Bedford McNeill to fill the vacant office. Your
thanks are due to Mr. Meeson for the able manner in which he
has organised the excursions during the past year. The Com-
mittee appointed to prepare an excursion programme for 1900

394 ANNUAL GENERAL MEETING.

was constituted as follows : Bedford McNeill (chainnto). Miss
Foley, Miss Whitley, H. A. Hinton, Frederick Meeson, H. W.
Monckton, A. E. Salter, W. P. D. Stebbing, and A. C. Young,
and it is recommended that the appointment of this Committee
be confirmed as soon as the new Council meets.

Your thanks are due to the Council of University College for
the facilities they continue to offer yon in the use of rooms for
your meetings.

As will be seen from the ballot papers now in your hands,
there are several changes in the House List. Mr. J. J. H. Teall,
having filled the Presidential chair for the past two years, now
retires from that office. You are indebted to him for an admir-
able account of the Natural History of so difficult a group of
minerals as Cordierite and its Associates. During his term of
office he has bestowed great care on the interests and welfare of
the Association, and those who have had the pleasure of being
associated with him on the Council readily acknowledge the debt
of gratitude that is due to your retiring President

Your thanks are also due to Mr. George Potter, who now
retires from the Vice-Presidency, and from the Council ; and to
the following members of the Council who retire on this occa-
sion: Mr. H. W. Burrows, Mr. T. V. Holmes, and Mr. J.
Hopkinson.

Your Council have much pleasure in proposing Dr. Charles
Barrois and Prof. W. M. Davis for election as Honorary
Members. Dr. Barrois' numerous memoirs on all branches
of geology have earned for him a well-merited distinction. On
more than one occasion he has rendered signal service to the
Association in the conduct of excursions. Prof. Davis is also
well known by his many papers on the physical aspects of
geology, and has recently contributed to your Proceedings a
valuable paper on "The Drainage of Cuestas." The present
wide-spread interest in questions relating to the forms of the
earth's surface is largely due to his writings, and to his influence
as a Professor.

The names of those suggested by your Council to fill the
vacant offices will be found on the ballot paper.

On the motion of the Rev. Prof. J. F. Blake, seconded by
Mr. J. D. Hardy, the Report was adopted as the Annual Report
of the Association.

The scrutineers reported that the following were duly elected
as Officers and Council for the ensuing year :

PROCEEDnCGS. 395

PKrsn^ENT :
W. \\-hiixk€T. RA.Lood.. F.R^^ F.GjS.

VicT-PrESIDEXTS :
H. W. M.--k-.rti, F.L-S^ F.G.S. C. Daries Sherbom. F.GjS.. FJIS.

E, T. Xcw-.cc. F R.S^ F.G 5. J. j. H. TcdI. M-A^ F.R^^ F.GjS.

TrEASVRER :

R. S. Herrks, M.A . F.G.S.

Secretaries:
Percy Eoiry. F.G.S. | Bcaiord McNdll, A.R^M., F.G.S.

Ei*rroR :
H. A. Allen, F.G.S.

Librarian :
Wheailcy J. Aikinson. F.G.S.

T'.VtLVE OTHER MEMBERS OF COUNCIL :

L. L- Belinfanie, M.Sc . B. es U .A. S. Kennard.

Gc-. C. Crick, .A-R.S^I., F.G.S. Frederick Mees^n.

Henrv Fleck. F.G.S. .\. E, Sailer. RSc. F.G.S.

Misi Marv C. Folev. B.Sc. W. P. D. Sieblang. F.G.S.

R H;.^i.nd. ' .Miss E. Whiilev, B Sc.

Dr. Euward Johnson. .A. C Young, h*.C.S.

The best thanks of the Association were then Toted to Ac
Officers and Members of Council retiring from office, to the
.\uditors, and to the Scrutineers.

The President then delivered the aiunial address, entitled,
" The Natural History of Phosphatic Deposits."

On the motion o[ Mr. H. B. Woodward, seconded by Mr.
Upfield Gteen, it was unanimously resolved that the President's
address be printed in full

ORDINARY MEETING.

Friday, April 6th, 1900.

W. Whitaker, B.A., F.R.S., President, in the Chair.

George Scoular was elected a member of the Association.

A paper was read by Mr. G. E. Dibley, F.G.S., on " Zonal
Features of the Kentish Chalk-pits between London and the
Medway Valley."

396

WIND-WORN PEBBLES IN THE BRITISH
ISLES.

Bt F. A. BATHER, M.A., F.G^, of ibe British Maseiim (Natml HistorrX
Plate XI.

{RtmJ MmrcA nd^ tgoo.)

IN the year 1868, Mr. R. D. Darbishire, of Manchester,
received from his friend, Mr. Naylor, a curiously shaped
pebble (PL XI, Figs. 6a, 6d\ This had been picked up by Mr.
Naylor as it was thrown out from the foundations of a house, then
being built by Mr Bellhouse, and now known as Groby Lodge,
at the comer of Groby Road and Racefield Road, near St
Margaret's Church, Bowdon, a suburb of Altrincham, Cheshire.
Details of the excavation are wanting, but reference to the
Geological Survey Maps of quarter-sheet 80 N.E. (scale i-inch
to the mile) shows that the underlying solid rock is believed to
be the Keuper Red Marl, but that it is covered here by a series
of Drift beds marked as Glacial Sand or Gravel. The writing on
the stone indicates that the foundation was actually in graveL
Other constituents of the gravel at this locality are not forth-
coming at present, so that for any further evidence we must turn
to the pebble itself.

The substance of the pebble is a hard, heavy, liver-coloured
quartzite. Apart from its peculiar shape, it is just such a stone
as those forming the bulk of the Bunter Pebble Beds ; and since
those beds crop out within seven miles to the north-east and six
miles to the west, there seems no reason to doubt that the Bowdon
pebble was once a part of them From what presumably
Cambrian rock these quartzite pebbles were originally ground
down is still matter of dispute among students of Triassic
geology. But this question, and even the question of its Bunter
origin concern us little, since, as will be seen, the characters that
give the pebble its main interest are such as must have been
imparted to it after its removal from Triassic strata.

Wlien the pebble is laid on a flat surface in its most stable
position, we may distinguish an upper and a lower half. As seen
either from above (PL XI, Fig. 6a) or from below (Fig. 6d\ the
periphery i.s roughly four-sided with rounded angles, and the
diameters of the subquadrangular figure are respectively 58*5 mm.
and 63*5 mm. The extreme height, when the stone is in the
same position, is 39 mm. The cubic contents are 84 95 cc., the
weight, 224-08 grams, and the specific gravity, 2*64. There is a
marked difference of form between the upper and lower halves.
The lower (Fig. 6^) is smoothly rounded just as one might expect
a roughly cubical fragment of sandstone to become under the
action of water and friction against other pebbles. The upper
Pkoc. Geol. .Assoc., \'0L. XVI., Part 7, 1900.]

WIXP-WORN PEBBLES IN THE BRITISH ISLES.

397

Diagram i. — Oi'tline of the
B4?wrox Pebble, a5 viewed

FROM ABO\'E, SHOmNG THE
RII»GES. tf, K c, AXn THE FACETS,
1,2, X. The ouier reciiiineal figure
suggests the approximate outline
of the stone before it was worn b\'
water or wind. X | diam

half (Fig. 6a) fonns a slightly irregular priainid, with, howerer,
three, not foar, facets. The relation of these facets to each other
and to the periphery is shown in Diagram i, from which it appears

that the pyramid is sym>
metrical neither in itself nor
in its relation to the quad-
rangle. The facets are not
plane surfaces ; facet 2 is
markedly convex, £aicet 3 is
concave, and £&cet i is con-
cave towards a, but almost
flat towards b. The aisles
between the facets are
slightly rounded, and this
fact, combined with the
inequalities of the fsicets
themselves, renders measure-
ment of the angles and
slopes a difficult task. The
approximate measurements
are: ridge a = 127 deg.,
b = 127 deg., r= 120 deg.
The slope of the facets to
the horizontal pbne, the
assumed surface of the original substratum, is measured along a
line bisecting the angle formed by the containing sides ; this may
perhaps be regarded as the angle of incidence of the focetting
force. These slopes are approximately : i ^ 24 deg., 2 = 45 deg.,
3 = 30 d^. Facet 2 appears from its size, its slope, and its
convexity, to be the least removed from its original water-
worn shaf)e. Facet i appears,
from its greater slope, and
from the position of the apex,
to be the most worn, although
the including angle contained
by the ridges a, b is the
smallest.

Besides these obvious
differences between the two
halves of the pebble, there are
differences in the nature of the
surface. Not merely are the
facets slightly rounded, but
their surfaces are irregularly pitted as well as very slightly grooved,
and differentiated according to the varying hardness of the stone.
This is chiefly noticeable on the two larger facets, i and 3, and
the 2:roo\nngs are at right angles to the dividing ridge a. Facet 3
has three broad grooves. Despite these irr^ularities, the surface,

Diagram 2. — The Bowdon Pebble,
viewed facing the ridge a.

X \ diam.

39^ F. A. BATHER ON

especially of facets i and 3, is slightly polished. The under-
surface appears rougher, owing to minute pitting, but it does not
show any coarser grooving ; except for an occasional obvious
dent or crack, it is all equably rounded. It further differs in the
presence of a slight yellow colouring. The distinctive surface-
characters of the under-side pass on to the upper surface, and
merge with those of the facets.

The remarkable features of this stone led Mr. Darbishire,
after thirty years, to send it to the Geological Department of the
British Museum, where, through the kindness of Dr. Henry
Woodward, it was placed in my hands for study. Since, during
an excursion of the International Geological Congress through
Esthland in 1897, my attention had been directed to pebbles of
similar shape, I had no difficulty in recognising the true nature
of Mr. Darbishire's specimen. Pebbles of this form are, in fact,
found in many parts of the world, and have long been known to
geologists under the names of " Dreikanter," pyramid-pebbles, or
facetted pebbles. Any theory of their origin must be applicable
to all cases, while the true explanation of any one will probably
be found to explain all.

The theory that ascribes the facetting, striation, and polishing
of these stones to the action of blown sand is now so generally
accepted that further labouring of the point might seem un-
necessary. But the present paper is due to the following
considerations. The explanation thus baldly given suggests many
- questions, some of which are not even nowadays readily to be
answered. There is a danger lest this theory be strained, as others
have been, to explain cases to which it is inapplicable. Very
similar results may be produced by other causes ; one must learn
how to distinguish. The subject seems to have been overlooked
by the majority of British geologists ; but if this paper should
serve as a guide to its possibilities and to the scattered foreign
literature, further light may be thrown by the study on the past
history of these islands.

Let us consider, first, the other agencies by which the surface
of broken rock-fragments or water-rolled pebbles may be worn.
Many of these have actually been adduced to explain the pebbles
in question.

Human agency naturally suggests itself to one familiar with
neolithic implements, and R. Virchow, describing pebbles of this
kind, believed that they had been used for polishing (1870a)* or
were preparatory to a finished stone weapon of primitive nature
(1870^); but in 187 1, having found similar pebbles in gravel beds,
he discarded his previous views in favour of a glacial origin. In
1874 similar stones were still ascribed to human agency by Reil
and Geiseler, but in the discussion their natural origin was advo-
cated by Ascherson and Virchow. Geinitz, in 1886, related how

* For References see p. 416

WIND-WORN PEBBLES IN THE BRITISH ISLES. 399

facetted i^ebbles from Pomerania and Rugen were still labelled
" Mahlsteine " in the Stralsund Museum. Even to this very year
a large quartzite pebble with four facets, from Uelzen in Hanover,
was preserved in the Ethnographical Department (Pitt-Rivers
Collection) of the Oxford University Museum. My friend, Mr. H.
Balfour, who was so kind as to send me the specimen for examina-
tion, wrote : "It is presumed it might have been a * rubbing
stone ' for grinding or other triturative use, and I have retained it
amongst the human tools." Now, however, he tells me that the
specimen is to be placed in " a special series for natural products
which simulate human workmanship, and may (seemingly do)
take in the collector of human artefacts." No undoubted tool or
weapon having the peculiar shape of these facetted pebbles has
ever been produced, and they are often found in situations where
a human origin is out of the question.

Other animals are not known to shape stones in this manner,
but it is to be noted that sheep, cattle, and the like often rub
stones to a high polish, while in South Africa rough masses of
igneous rock are smoothed, polished, and marked with coarse
parallel striae by the rhinoceros. Specimens have been presented
to the British Museum by Mr. David Draper.

The waving of grass against a stone often produces consider-
able polish, especially when the grass contains much silica.

Stones polished and facetted by glaciers generally differ from
those worn by blown sand in one or more of the following points :
the ground surface is flatter; they show characteristic glacial
striae— long, straight, and gradually tapering ; the harder and
softer components of the rock have not been differentiated.
Nevertheless the glacial origin of many pebbles now believed to
be wind-worn has been warmly advocated (Theile, 1885-86 ;
Keilhack, 1884) ; Emerson (1898) still assigns the Dreikanter, at
least in Old Hampshire County, Mass., to glacial agency ; but
although such pebbles have been found on the surface of terminal
moraines, and even of the glacier itself, still the actual formation
of the characteristic shape by a glacier has never yet been
adduced. Indeed, it is not easy to see how the three regular
facets of such a stone as our Bowdon pebble could be produced
by glacial action.

The same remarks apply in the main to C. von Gutbier's view
(1858) that the stones were fixed in floating ice and ground
against a rocky floor, with the additional difficulty that, if the
stone were loosened sufficiendy for it to be turned round for the
grinding of a fresh facet, it must have fallen to the bottom. It is
not denied that stones are ground by this agency. Among
facetted stones usually ascribed to ice action are the well-known
pebbles of the Punjab. After reading the literature bearing on
these,* and minutely examining the specimen described by Dr.

• BlanfortI, 1886 ; Noctling, 1896 ; Oldham, 1887 ; Stone, 1889 ; Warth, 1888 ; Wynne, 1886.

400 F. A. BATHER ON

W. T. Blanford (Nov., 1886), I agree with most of the writers on
the subject that, whatever be the agency that shaped these stones,
it was not blown sand.

The action of water, or of water and sand, has been known
to grind stones in a manner other than the normal rounding.
Professor Boyd Dawkins tells me of an instance on the coast of
Cornwall. There he observed a number of stones ground on one
side to a sharp edge, so that he took them for implements, until
he saw that they had originally projected from a bed of clay, over
which the tides swept sand backwards and forwards in such a
way as to grind the exposed portions. In the discussion on
Virchow's paper (1871), Braun supposed that the shape of the
typical pyramid-pebbles was produced by one stone rubbing
against another when disturbed by running water. This idea
was elaborated in the " Packungstheorie " of G. Berendt ^1885),
who imagined that, as water passed through a bed of shingle or
gravel, the pebbles were rubbed one against another, and so
tended to assume a pyramidal shape as the most economical of
space. This theory proves too much, for had such been the
modus operandi, the stones would have been facetted both above
and below, whereas such " Doppel-dreikanter " are extremely
rare. The explanation is further inapplicable to those numerous
facetted pebbles that occur where the presence of water is out of
the question. It is, however, possible that the action described
by Berendt does have some effect. F. E. Geinitz (1887) believes
that facetted pebbles are thus produced in the beach at Heilige
Damm, in North Germany, and he quotes Commenda ( 1 884) who, in
giant*s cauldrons at Steyregg, Austria, discovered ** Dreikanter of
a hard garnetiferous greenstone" along with ** round, yellow gravel,"
the whole covered by Danube alluvium. These particular pot-
holes arc ascribed to the meltmg of glaciers.

In the pebbles of the Bunter Beds* there are often found con-
cavities, which Mr. Mellard Reade ascribes to the grinding of one
stone upon another, assisted by water and perhaps sand. Others,
noting the transversely fractured pebbles of these beds, as well as
the frequent occurrence of cracks radiating from these depressions,
have regarded pressure due to earth-movement as the cause of
both phenomena. In the Lower Old Red Sandstone conglome-
rate of the Cushendun caves, Antrim, Mr. Upfield Green has
collected a rounded quartzite pebble with one side striated and
polished. This resembles the glaze produced by blown sand ;
but, since the stone has been crushed and cracked by pressure,
and since the striae are all parallel to its long axis, I believe the
polish to be the effect of slickensides. Allusion may here be
made to soil-cap movement, which striates and grinds underlying
rocks. Typical Dreikanter rarely occur in situations where any

• Sec Ramsay, 1855.

WIND-WORN PEBBLES IN THE BRITISH ISLES. 4OI

of these explanations are at all admissible. It is, however, the
case that those of the German Drift are often marked, on the
facets and elsewhere, by round hollows, up to 2 cm. in diameter,
and of varying depth. These were ascribed by Gutbier (1858)
to the driving of one stone into another under ice-pressure, in
which case, as in that of the Bunter pebbles, one would expect to
find the stones more crushed and cracked. The slight grooves,
sometimes as much as 10 cm. long, which occasionally run up to
these hollows, do not appear to represent cracks. Wittich (1899)
who supposes the excavating agent to be blown sand, suggests
that some of the holes may be due to the former presence of clay
galls or calcareous fossils. Some of the smaller depressions or
pittings may be due to the alternation of extremes of temperature,
since this is known to flake portions off stones, especially in
desert regions. To this cause may possibly be due the pittings
on the under surface of the Uelzen pebble in the Pitt-Rivers
collection.

In the case of composite rocks, such as the coarser crystal-
line igneous rocks, the difference in co-efficient of expansion of
the constituents renders the stone easily attacked by variation of
temperature. This factor in desert regions and the freezing of
water in the joints under a moister climate, cause the breaking up
of rocks into angular fragments. Thus Rothpletz, Johnstrup
(1874), Shaler (1889), and Keilhack (1884) have attempted to
explain at all events the main contours of the facetted pebbles ;
but we have yet to learn of a rock in which the joint-planes lie
at the angles usual in pebbles facetted by blown sand.

Some of the appearances characteristic of undoubtedly wind-
worn pebbles may be closely simulated by the solvent action of
water, with or without acids. The glazed surface closely resembles
the so-called " fresh- water patina," and among similarly polished
stones may be mentioned the bones and teeth found in the
English Red Crag, and the small pebbles of chalcedony, quartz,
and flint in the Red Chalk of Hunstanton. Geinitz (1886) has
even denied that the facets of Dreikanter are distinguished by
extra polish ; but in this opinion he is singular. Writing of
certain pebbles found in the drift of Nantucket, Shaler (1889)
says they " may be compared to crystals of rock-candy partially
dissolved away. The surface of the boulders becomes very
smooth, though uneven ; in some cases pebbles or crystals contained
in it are left as rounded projections on its face." This effect is most
conspicuous in siliceous pebbles, and in no case is it observed so
much as 10 ft. below the surface of the soil. Shaler ascribes it to
the action of surface waters containing carbon dioxide, and he
carefully distinguishes it from the erosive action of blown sand,
which is said to be inconsiderable there. None the less the
description is precisely applicable to certain wind-worn stones;
and it must be remembered that certain facetted pebbles from
Proc. Geol. Assoc., Vol. XVI, Part 7, May, 1900.] 30

402 F. A. BATHER ON

the same beds, ascribed by Shaler to joint-fracture and ice-polish,
are now explained as wind-worn (Davis, 1894).

As for polish, Baltzer (1896) says that " Gletscherkanter," worn
down under the glacier in ground moraines by the finest loamy
sand, show the varnish polish just like wind- worn stones.

We may now consider undoubted instances of the action of
blown sand, with special reference to facetted pebbles.

Not far from Wellington, New 2^aland, is an isthmus, a little
over a mile across, separating Evans' Bay on the N.W. from
Lyall's Bay on the S.E. In the middle of this is a ridge of
boulders and pebbles, and on each shore the sand is piled up in
dunes. The isthmus is confined on the N.E. and S.W. by hills.
When the north-westerly winds blow through the gap, which is only
half a mile wide, they drive the sand over the boulder-bank with
much force, and when the winds change to the south-east, the
sand is driven back again. These happen to be the two prevalent
winds, and in any case the area is protected by the hills from the
action of other winds. As a result the stones of the boulder-bank
are planed off on the two sides opposed to the winds. At first the
top of the stone remains fiat, but at last the two sides meet in a
sharp edge.

Similar stones, fashioned under much the same conditions,
are met with in other parts of New Zealand — e.g.j on Hokitika
beach, on the west coast of South Island. One of these, figured
on Plate XI (Fig. 5), shows, at the upper end of the figure, a
small facet, apparently the remains of the flat top : thus there are
three ridges. But it does not appear that any of the stones from
New Zealand localities assume the markedly triquetrous form of
our Bowdon specimen and of the German " Dreikanter " ; and
this may be the reason why the explanation of the former by
Travers (1870) and Enys (1878) was not applied to the latter
until (iottsche in 1883 drew attention to it.

In attempting to explain the triquetration, we must remember
that, even where most conspicuous, it is by no means found on
all the specimens. In fact, a pebble may present almost any
number of facets, from one to at least eight. Even when the
number is three or four, there is great variation in the relative
sizes and outlines of the facets. It is, however, convenient to
take the Dreikanter as the type, and of this form we find the most
convincing elucidation by A. Mickwitz, of Reval (1885-87).
South of that town is a lake, the Ober See, and its north-west
shore ('^nordostlichen," Mickwitz, must be a lapsus calami) is
covered by sand dunes. Where the Pernau Road and the
Baltischport Railway approach the lake, the dunes merge into
gravel banks and terraces, which stretch westward to a sandy
plain north of the Blue Hills. The sand from one side or the
other is constantly being blown over the gravel ridges, and all the
surface constituents of the ridges, from fine gravel to massive

WIND-WORN PEBBLES IN THE BRITISH ISLES. 403

blocks, have their upper sides polished by the sand, while on the
under side they differ in no way from ordinary drift gravel.
Regularly facetted stones do not occur at the lower levels, but are
abundant on the higher terraces, and their most conspicuous,
though far from commonest, form is the Dreikanter. Between these
and the simply polished stones there is every gradation. Both
are alike in showing a differential wearing of the constituents of
the rock, producing ridges, rugosities, and pittings. Now, if the
facets of the Dreikanter are due, as in the case of the New
Zealand pebbles, to the prevailing winds, one would expect to find
them all oriented alike, although allowance might have to be made in
each case for the deflection of the wind by local conditions. This
is actually the case, as Mickwkz has proved by taking the bear-
ings of a large number. Furtlrer, one would expect to find three
prevailing winds, acting at right angles to the mean direction of
the facets, viz., N., S. by 50 deg. W., and S. by 60 deg. E. This is
believed by Mickwitz to be the case, but on this point his
observations are not yet published. Moreover, the local condi-
tions appear to have undergone recent change, since woods have
grown up which shelter the Dreikanter terrace, and permit lichen
to grow over the stones, especially on their southern sides. Some
of the stones from this classical locality are figured on Plate XI,
and show many of the characters to which allusion has been
made.

For more complete correlation of facets with prevailing winds,
we turn to the valuable paper by Baron G. de Geer, of Stockholm
(1887). The stones described by him have, however, only two
facets for the most part. They were found at Fjelkinge, on a field
where rye had been grown two years before, and where a fresh
surface had consequently been exposed by the plough. The
mean direction of the ridge between the facets was N. by 22 deg.
W., and the prevailing winds at the neighbouring meteorological
station of Kristianstad were at right angles to this direction.
Moreover, the field was sheltered from other winds by adjoining
hills, so that the conditions were doubly favourable.

The foregoing instances are enough to show that blown sand
is an effective cause of facetted pebbles, including Dreikanter.
They are corroborated by the observations of Stone, on pebbles
in Maine (1886) and Colorado (1889); of Wahnschaffe (1887),
on pebbles at Graningen, near Rathenow; of Dames (1887), on
pebbles below the Regenstein in the Harz; of Walther (1887), in
Egypt; of Verworn (1896), in the desert of Sinai; and of
Andersson (1896), on Gotska Sandon, in the Baltic. We may
now proceed to discuss the process in more detail.

It is often supposed that the wind in action strikes the stone
in the direction of the ridge and is divided by it, so that a stream
of sand passes to right and left, forming two facets. Those of
the above-mentioned authors, however, who have attempted

404 F. A. BATHER ON

correlation of the facets with the prevailing winds, agree that the
wind acts at right angles to the ridge. This, as Wahnschaffe
says, is further proved by the frequent hollowing of the facet
Groovings and striations of the facets also run in this direction,
as may be seen in Fig. 5 of Plate XI. Heim (1888), while
admitting this in the main, ascribes more importance to the
original form of the stone than to the direction of the wind.
Each facet, he says, corresponds to a truncated side of the
original pebble, and a sharp notch on any side results in a groove
on the facet ; a wind blowing from any direction is diverted by
the face of the pebble, and, whether from right or left, would
have precisely the same action on that face. This might be the
case if that particular face were the only part of the pebble
exposed to the eroding agent. But, as Heim himself says, the
ridges are produced where the side attacked by the wind meets
the sides sheltered ; and it is clear that when the wind is S.E.,
that portion of the pebble sheltered is not the same as when the
wind is S.W. In other words a S.E. wind attacks not only the
southern face, but also the eastern face, and wears down the
S.E. ridge between them. The action of a S.W. wind is quite
different. But anyway Heim's assertions are made without
attempt at proof.

It is, of course, obvious that, at least in the earlier stages, the
original form of the pebble must have some effect. The trunca-
tion of two corners of a four-sided pebble would make it six-
sided, and so forth. A rounded pebble attacked by winds from
the S.E. and S.W. alone would become a Dreikanter, with two
flat or concave facets due to blown sand, and the third the original
convex surface. It is probable that facet 2 in the Bowdon
specimen is such a surface, and this would account for the less
polish and pitting of it as compared with facets i and 3. The
Reval specimens, represented in Figs. 2, 3, and 4 of Plate XI,
do, on the contrary, appear to be wind-worn on all three facets ;
and the fact that, in each of these pebbles, the facets harmonise
with the outline, may be due to something more than chance.
Similarly the four facets of the Uelzen specimen (Pitt-Rivers
coll.) coincide with the four sides of the stone, and are all wind-
worn. In this case there is a median ridge parallel to the long
axis of the pebble, and two ridges diverging from each end of it.
Thus the facets are two large and two small, and this arrangement
is characteristic of pebbles with four facets. In this case two of
the ridges, diagonally opposed, are well marked ; the other two
are rounded. This suggests that the stone was subject to the
action, not of four equally persistent winds, but of two main
winds which occasionally veered into the adjoining quarter.
Wittich's remark (1899) that long pebbles usually have but one
ridge running lengthwise, is certainly borne out by the Hokitika
specimens that I have seen. Some of these also show how stones

WIND-WORN PEBBLES IN THE BRITISH ISLES. 405

with vertical sides (not necessarily thick, />., high, fragments, as
Wittich says) are first smoothed on those sides, so that the stone
retains a flat top, with edges parallel to the periphery of the stone.
The relic of such a top is shown in Fig. 4 of Plate XI, and there
is a trace of it in the pebble represented in Fig. 2. Wittich
also notes that fragments of Bunter sandstone usually have
a parallelepipedal form, and their wind-worn facets are conse-
quently rectangular as a rule. The Reval specimen shown
in Fig. I of Plate XI has but one definite facet, though
the rest of the upper surface is polished. Another specimen
collected at the same time is of similar size, shape, and polish ;
but whereas the facet of the figured specimen faced south,
that of the other specimen was turned to N.N.W. These
two pebbles, then, seem to have been affected by minor local
conditions.

The number of facets on a stone may then be due partly to
its original shape, partly to the number of prevailing winds acting
on that particular stone. But the number may be increased by
other aspects of the pebble being opposed to the winds. This
may be brought about by a change in the surroundings deflecting
the winds, or depriving the stone of some shelter it originally
enjoyed ; or, as is more usual, by some shifting in the position of
the stone itself. Such shifting may be readily caused by the kick
of a passing animal, and a recurrence of the accident might
multiply the facets indefinitely. But the wind itself may alter
the position of a stone, not, except in the case of smaller, loosely-
strewn pebbles, by actually blowing the stone over, but by wearing
away the ground on which it lies. This phenomenon is common
on a sandy soil. The surrounding sand is first blown away,
leaving the pebble as the cap of a small earth-pillar, which is at
last eroded to such an extent that the pebble topples over, and
presents another surface to the destructive agencies. In some
such way may be explained the Doppel-dreikanter, which are
occasionally found. The wearing of the stone on its under
surface may, as Wittich (1899) points out, take place while it is
still the top of an ajolian table; the stone becomes pointed
underneath. A similar mushroom form is seen in larger masses in
the desert. But the more usual effect of undermining action is to
prevent the formation of pyramid-pebbles entirely. The stones
are rolled over so constantly that time is not allowed for the pro-
duction of perceptible facets, but the whole stone acquires a fine
polish. This is exemplified by the smaller pebbles of the Cairo
desert, and was also seen in many of the New Zealand speci-
mens exhibited by Mr. G. J. Binns when this paper was read.
Undermining does not take place to an appreciable extent when
the pebble rests on, or is imbedded in, a clayey substratum ; but
that this condition is necessary for the production of Dreikanter
is disproved by many instances.

4o6 F. A. BATHER ON

The observations of Walther (1887-91), chiefly made in the
Galala Desert, between the Nile and the Red Sea, are of much
importance. He denies that there is any causal connection
between the number of facets and the size of the pebble, and has
failed to discover any connection between the direction of the
edges and that of the winds. This seems to upset the theories
of Mickwitz, De Geer, and others ; but, as Walther points out,
the wind in the desert is very inconstant, and allowance must also
be made for the frequent shifting of all the pebbles. Attention must
therefore be directed chiefly to the environment of the individual
pebbles. Facetted pebbles, he explains, always lie among other
pebbles : the sand flows in streams along the ground, and these
streams are divided by the larger pebbles and again unite ; stones
on which two such converging streams impinge acquire two facets
(and ultimately three ridges, as explained above). Stone's
observations (1889) at the base of the Rockies are in harmony
with the above. The boulders present " polished facets in all
positions with respect to both vertical and horizontal planes.
A single boulder may have a dozen or more facets. . . . The
grooves often have different directions on different faces ; but in
places where the wind can only act when blowing in a certain
direction, they are parallel. They can often be traced up to a
facet angle and around on to the next facet, especially when the
angle is quite obtuse. Grooves can be found at all angles to
facet edges, both parallel and transverse to them. The positions
of the facets ... are determined partly by the original
shape of the stone, and partly by the accidents of the grinding
process." "Several facets can be formed contemporaneously."
Thus we see, not only how a single wind may produce two facets,
but how all the variable breezes from half-way round the compass
may be deflected into an unvarying channel. At the same time
if this were a complete explanation of all Dreikanter in other
situations, the observations of Mickwitz, De Geer, and Wittich, as
to the correspondence in orientation of the facets, would be
themselves inexplicable.

We note here a difference between the action of blown sand
on bosses of live rock and on stones lying on sand or gravel. In
the former case, as instanced by Stapf (1887) from the stone
desert of the ! Khuiseb valley as well as along the Guadiana above
Mdrida and at Caceres, the first results are "smooth, rounded
humps, to be distinguished from glaciated humps only by their
rougher surface, the absence of [glacial] striae, and the want of a
sharp lee side." But with loose stones, the ultimate form is
neither this nor a plane surface, owing to the constant undermining.
From this and preceding considerations it may be inferred that
the connection between a facetted pebble and such persistent
conditions as the winds of the locality will best be observed in
the larger pebbles. Such facetted stones as those figured by

WIND-WORN PEBBLES IN THE BRITISH ISLES. 407

Theile (1885), 17 and i'6 metres long, would not readily be
displaced.

As introduction to the minuter and more specific characters
of wind-worn stones, it will be well to consider the action of the
sand-blast, whether natural or artificial. It is often assumed (as
seemingly by Mickwitz) that the formation of marked facets must
have been the work of centuries. De Geer's observations (1887)
will already have caused us to doubt this, and they are confirmed
by others. In other respects the natural action of blown sand is
well known to be often severe. Long ago Graf von Baudissin
(1865) related how, on the island of Sylt, the window-panes were
cut through by dune sand. The same occurrence is recorded by
Winchell (1886) from Cape Cod. Telegraph wires, says Wittich,
are cut by sand on Russian steppes. Gilbert, in the discussion on
Davis' paper (1894), said that fifteen miles east of Watertown, in
northern New York, pebbles had been carved within a few years
of the clearing of the surface. Among pebbles kindly collected
for me by Mr. Mellard Reade from the sandy beach of Crosby,
north of Liverpool, are pieces of bottle-glass with fresh, bright
fractured edges, but with the exposed upper surface ground by the
blown sand, and with striae in groups at different angles. The
action of the artificial sand-blast is remarkably rapid ; by its use
De Geer brought a freshly broken face of quartzite to the
characteristic pitted and polished surface in fifteen minutes.

The effect of the sand-blast on rocks has been investigated by
Tilighman '(who is quoted by Woodworth, 1894) and especially
by Thoulet (1887). I abstract so much of the latter's paper as is
germane to the present issue. Abrasion varies directly as the
quantity of sand. Polished rock resists abrasion better than
unpolished, and fresh unworn sand abrades quicker than
worn sand. The coarser the sand, the more rapid the action.
Abrasion varies directly as the pressure of the wind. Abrasion is
most intense when the surface is perpendicular to the sand-stream ;
it diminishes rapidly when the angle of incidence is below 60 deg.
Fine-grained rocks, whether heterogeneous or homogeneous, resist
abrasion better than coarse-grained. A rock is abraded more
rapidly when moist than when dry, and the more so the more
porous and absorbent it is. If Woodworth is correct in quoting
Tilighman to the effect that the cutting is more rapid when the
angle of incidence is 30 deg., and if Woodworth's other remarks on
this point are based on Tilighman, then the observations of the
latter are irreconcilable with those of Thoulet.

Applying Thoulet's conclusions to the operations of nature,
we see that these must be more effective at first, and that a point
would be reached when, owing to the polish of the pebble, the
smoothness and fineness of the sand-grains, and the slope of the
facets, scarcely any abrasion would be in progress. Pebbles
which might originally have had very various forms, would

4o8

F. A. BATHER ON

gradually approximate so far as the slope of their facets was con-
cerned, and thus would arise that mechanical similarity of angle
which has led some authors to compare it even with the results of
crystallisation.

Thoulet's opinion as to the effects of moisture must surprise
those who associate excessive wind action with an abnormally dry
climate. This laboratory result is in fact little applicable to
nature, for the rain that moistens the rocks also lays the sand and
dust. Moreover, in humid regions, such traces of sand action as
might from time to time arise are speedily obliterated by the
more rapid wasting due to decomposition and solution (Gilbert,
1875). In this connection it may be remembered that dryness
does not imply heat. Allusion has already been made to wind-
worn pebbles on the surface of glaciers, and Chelius (1892) has

recorded the
blowing of sand
and dust over
snow near Darm-
stadt As is well
known, snow
itself may re-
place sand as
the corroding
substance.

The chemi-
cal composition
and the texture
of rocks have
CO nsi derable
influence on
the form of
facetted peb-
bles. In the
Sahara, according to Rolland (1890), blown sand chiefly works on
limestones. Walther says that in the Galala desert Dreikanter
are formed only of Cretaceous limestone, having a fine, compact,
uniform grain ; Eocene limestones are too soft ; nummulitic
limestones too unequal ; the crystalline rocks quickly decompose.
In more northern latitudes fine-grained quartzite seems to be the
rock that receives the smoothest surface and the most sym-
metrical facets, the latter feature, however, depending rather on
the original shape of the stones than on their texture. Milky
quartz and flint are not so well carved. Composite igneous rocks
have their constituents differentiated, as is well seen in the granite
pebble from Reval (PI. XI, Fig. 2, and Diagram 3). The same is
the case with conglomerates and stratified rocks in which the
laminae are of unequal hardness. A slight grooving due to the latter
cause is seen in the Uelzen specimen (Pitt-Rivers coll.). Witlich

Diagram 3— A Pebble from Reval (Pl. XI,
Fig. 2), VIEWED from the side to show
Elevation, Truncate Apex, and Ter-
racing OF Sides due to Differentiation
OF Constituents, x J diam.

WIND-WORN PEBBLES IN THE BRITISH ISLES. 409

describes wind-worn blocks of coarse conglomerate which are
derived from the Upper Bunter Sandstone and are found in the
drift of the Main, near Frankfort ; in these each pebble stands
out and has its own facets. The same is the case with the Khan-
Khaisk conglomerate of Central Asia. A frequent result of this
differential action is the production of a step-like or terraced
appearance on the facets or other worn surface (Diagram 3), and
it is noteworthy that the same api)earance on a larger scale is
often seen in the hill scenery of desert lands (see RoUand, 1890).
So characteristic are the different shapes and surfaces that slight
practice enables one to distinguish the composition of the
pebbles from photographs alone with some confidence (see the
plates of Davis, 1894; Berendt, 1885; and others). Obruchev
(1895) has classed the rocks of the Central Asian deserts into
eleven groups, according to their mode of wearing under blown
sand.

The fluting of rock-surfaces by blown sand does not appear
always to be due to the composition of the rock, but to the direct
action of the blast. If the wind be exceptionally strong, with its
force perhaps enhanced by concentration in a gully or cleft, as in
the Pass of San Bernardino, California (Blake), the abrading force
is so greatly increased that hard materials yield to it nearly as
much as soft. In other words, differentiation is greater when the
force is enough to attack soft, but not enough to attack hard,
minerals. If now this fierce blast be broken iip into streamlets by
superficial irregularities, each streamlet will carve for itself a small
runnel, which will proceed straight forward for an appreciable
distance without regard for hard and soft. Thus one must
explain the remarkably carved surface of the basalt boulder in
Colorado, beautifully figured by Gilbert (1875, P^- ^"0- To such
action also I am inclined to ascribe the appearance of the fluted
granite surfaces at Mount Sorrel, Charnwood Forest, examples of
which have been lent me through the kindness of Prof. W. W.
Watts, who has recently drawn attention to them (1900).

Grooves due to direct wind action and not to rock texture are the
subject of valuable speculations by Stone (1889). The facets of a
small stone " nearly on the same level as the surface of the soil or of
other stones around it " often have " a gently undulating surface,
the crests of the low undulations more often being transverse to
the direction of the wind and an inch or more apart." In this
case " a large part of the carving is done by flying grains as they
first strike the stone.*' In the case of bigger or loftier surfaces " a
much larger proportion of the grinding is done after the blowing
stones [grains] have once rebounded from the fixed stone." The
grains, being mostly of irregular shape, bound from side to side,
and thus form " shallow grooves parallel with the direction of the
prevailing wind , . . an inch or less in breadth and seldom more
than the sixteenth of an inch in depth." These " grooves can not

41 0 F. A. BATHER ON

seldom be traced up and over a long transverse undulation, or
they give rise to a large number of conchoidal depressions."

This branch of the subject cannot now be pursued further.
Allusion may, however be made to the remarkable effects of wind
described and figured by RoUand (1890). In the south of the
Sahara certain plateaux are polished like a looking-glass, with
striae, grooves, etc. The flanks of certain hills — e.g,, Gour
Ouargla (near El Golea)— are engraved, sculped, bored, and
reduced in places to a regular stone lacework, of which the
pattern sometimes allows one to recognise the direction of the
wind. Here, also, are pebbles of limestone and silica, with the
surface covered by vermiculate grooves like arabesques.

The polish so often alluded to as a result of the sand-blast is,
of course, confined to the harder rocks. Baltzer (1896) dis-
tinguishes " glanzende Politur " (bright polish), especially seen on
compact and finely crystalline limestones, from " matte Politur "
(dead polish), seen chiefly on sandstones and coarsely crystalline
limestones. But every gradation is to be found. Nearly all
writers compare this polish to a varnish; Stapf (1887) says, "a
glaze-like polish " ; Blake (1855) writes, " The polish is ... as if
the pebbles had been oiled and varnished." What is the diflerence
between a glaze or varnish and a surface polished by rubbing ? It
appears to me to be essentially an optical effect due to the
irregularity of the varnished surface, as contrasted with the
regular smoothness of the rubbed surface. In the former case
the rays of light are reflected at all angles and from various levels.
This is just the character of the wind-worn surface ; the polish
lies equally on eminences and depressions, and minor irregulari-
ties are in fact increased rather than diminished by the sand-blast.
A pebble that is wind-worn above and water-worn below, appears to
the eye smooth above and rough below ; but to a sensitive finger,
or to the tongue, it is the under surface that appears smooth, while
the shining upper surface is full of irregularities. A surface
polished by glaciation or water-grinding feels smoother.

This "varnish" or "patina" of desert pebbles, which increases
the blinding eff*ect of the reflected sun, and which must assist the
mirage in deluding the traveller with the vision of water, must
not be confused with another characteristically desert patina.
The " rocs vernisses noirs " of E. Reclus are indeed supposed by
Rolland to be dark Devonian sandstones polished by sand. But,
as he points out (1890, p. 216, footnote), there is also "a sort of
black patina, formed, no doubt, under atmospheric and solar
action. In the same way the white Cretaceous limestones of the
Algerian Sahara are often covered by a yellow patina, e.g,^ on the
plateau of El Golea." This kind of patina still needs explana-
tion ; some (e.g., Obruchev, 1895) suppose it to be connected
with the chemical composition of the rock, a sort of efflorescence
of silica and iron ; at any rate, it is no effect of blown sand.

WIND-WORN PEBBLES IN THE BRITISH ISLES. 4II

The effects of wind and other desert conditions have a more
than terrestrial interest; Goldschmidt (1894) has figured and
described similar appearances on the surfaces of meteorites.

Facetted and wind-polished pebbles have been found over
almost all parts of the present surface of the earth, under tropical,
temperate, and Arctic climates, on plains, on hills, or in valleys,
scattered over steppes and deserts, or confined to small clearings
in the midst of fertile fields and evergreen forests. Here are a
few recorded localities : Deserts of Libya and Arabia (Walther,
1887-91); Desert of Sinai (Verworn, 1896, Sarasin) ; Kala-
hari Desert of S.W. Africa (Stapf, 1887) ; 16 kilometres from
Walfisch Bay, S. Africa (Captain T. Een, fide De Geer) ; Deserts
of Central Asia (Richthofen, Obruchev, 1895) \ Reval (Mickwitz,
1885); Schleswig-Holstein (Gottsche, 1883; L. Meyn, 1872);
Jutland (Johnstrup, 1874); Anholt in Kattegat (Torell, fide De
Geer, 1887) ; Silfakra, near Lund, East Scania, and N. of Fjelkinge,
near Kristianstad (De Geer, 1884-87) ; Halland (Lundbohm,///<f
De Geer, 1887); Iceland (Keilhack, 1884); sandy plateau of
Brenne, in France (Lapparent, 1899); surface of old moraines
near Lyon, collected by Chantre {fide Torell, apud Berendt, 1889,
and De Geer, 1887); New Zealand, various localities (Travers,
1870; Enys, 1878); California (Blake, 1855); Colorado (Stone,
1889); Nebraska, Bad Lands (Gilbert and others); Maine, espe-
cially near Bethel (Hitchcock, 1861 ; Stone, 1886) ; New Jersey
(Salisbury, 1893); northern New York (Gilbert, 1894). Many
of the facetted pebbles from Germany may likewise be of recent
origin.

The geological occurrences of facetted pebbles are mostly in
the Drift, and the pebbles received their present form in Post-
glacial times. The localities in Germany are too numerous to be
quoted here ; they will be found recorded in the papers by Berendt
(1885), Chelius (1891,-92,-94), Geinitz (1886,-87), Gutbier
(1858,-65), VVittich (1899), and others. As the last-named author
remarks, in Germany the Dreikanter were deposited where they
now are in middle or old diluvial times : but they were facetted
during the succeeding young diluvial epoch, the Loess period, or
even the present day. The Loess itself is too fine to have abrasive
power, and the wind which transported it did not, of course,
transport pebbles along with it. Facetted pebbles are, however,
frequent in the basement bed, or " Steinsohle," of the Loess, being
always found in the topmost covering layer of the underlying
Drift, whatever that may consist of, over the whole North German
Plain (Sauer 1889). In Saxony, for instance, Herrmann (1880)
and Weber (1890), tell us that facetted pebbles are rare in Loess-
lehm, more numerous in the coarser sand and in the Steinsohle.
A typical case is described by Wittich (1899), who found Drei-
kanter in their original position in drift gravel beneath blown
sand, at i metre from the present surface, in a pit at the Town

412 F. A. BATHER ON

Electric Works of Isenburg. The most polished side faced S.W.,
the other facets were N.E. and N.W. No evidence as to the
present winds of that locality is given. The pebbles of Cape Cod
have already been discussed (see Davis, 1894). So, too, Wood-
worth (1894) observed in Matakeset Creek, S. New England :
** A continuous line of sculptured and polished pebbles lying at
an average depth of from one to two feet beneath the surface,"
" overlaid by a deposit of fine wind-blown beach sand." The
under surface of the pebbles, where in contact with the underlying
gravels, was not facetted, and no facetted stones were found in
the underlying gravel. Woodworth concludes that the facetted
pebbles are " evidently glacial stream pebbles reshaped in sifu"
The conditions at the close of glaciation in any country must
have been most favourable to the production of pyramid-pebbles.
The land was bare and exposed to winds ; its surface was strewn
with boulders and pebbles, many of them already ground to an
appropriate shape ; and there was associated with them an abun-
dance of angular sand, far better for the work than marine sand.
These facts account for the association of pyramid pebbles with
glacial deposits, an association so frequent as to' have led Prof.
B. K. Emerson (1898) to the rash assertion that they are "as
characteristic of the till as graptolites of the Silurian." Neverthe-
less, as Gottsche (1883) has warned us, the pyramid pebbles of
the Drift characterise no particular bed, and the period of their
facetting extends from glacial times to the present day.

From formations of a remoter past, a few cases have been re-
corded of facetted pebbles, probably ascribed with justice to the
action of blown sand. Thus L. Meyn (1876) claims to have found
pyramidal pebbles in situ in kaolin-sand of Miocene age on the
island of Sylt. Professor T. Rupert Jones (1878), among pebbles
of " quartz, quartzite, and lydite from the conglomerate, or pebbly
and gritty bone-bed, of the * Upper Tunbridge Wells Sandstone'
in the quarry at Whiteman's Green, near the town " of Cuckfield,
found some which showed in parts " a glaze-like polish " with
"delicate parallel striae" and one with a "triangular shape."
He assigned these appearances to the action of blown sand on the
shores of the Wealden estuary. The stones were distributed
between the museums of Brighton and the Staff College, but are
not now to be seen. Chelius and Klemm (1894) have recorded
pebbles with sharp ridges and with one or all sides finely polished,
from the Middle Bunter conglomerate of Radheim, in E.
Odenwald. They regard them as " not unlike " Dreikanter.

The most striking instance of fossil Dreikanter is that described
by Nathorst (1886^, b). Quartz pebbles, having this characteristic
shape, and smaller pebbles worn on all sides, are found at
Lugnas in Vestergotland in the Eophyton sandstone of Cambrian
age. The associated remains indicate that these pebbles lay on a
sea-shore, or on sand dunes close to a shore (Nathcrst, i886r).

WIND-WORX PEBBLES IN THE BRmSR ISLES. 413

In Britsdn wind-worn pebbles do nol seem to have been
noticed often, or else those who have noticed them have not been
at the pains to record their occurrence.

Besides the Bowdon pebble, the pebbles described by Prof.
Rupert Jones, and the Mount Sorrel surfaces noticed by Prof.
Watts, I can find nothing definite, although in the discussion
on Enys* paper (1878) Sir John Evans "referred to \*arious
examples of stones polished by blown sand occurring in this
country."

Mr. S. S. Buckman has searched the neighbourhood of
Cheltenham, and has sent me various pebbles, some of which
bear traces of wind action, From Bengeworth, near Evesham,
in the Avon Valley, where much Northern Drift covers the Lias,
come two pebbles 27 and 33 mm. long, of veined quartz and
chert respectively, each glazed on the upper sur^M^e, the smaller
one having a fairly distinct and slightly concave facet. At
Beckford, seven miles north of Cheltenham, Mr. Buckman found
a red quartzite pebble, 40 x 31 mm., water-worn, but with three
facets which have not met so as to form ridges ; the difference in
form and colour between these red facets and the remaining
water-rounded and stained surface is dearly marked. This was
found at 130 ft. O.D., loose on gravel consisting of Oolite
fragments, and a few Northern Drift pebbles ; the gravel lies over
sand containing a few fragments of Oolite. Similar sand,
similarly situated, at Charlton Kings is false-bedded and composed
of rounded grains, and may be blown sand. The soil above the
gravel at Beckford is rich in rounded siliceous particles, '25 to
•5 mm. in diameter. None the less, I am doubtful whether the
facets are due to blown sand ; had they been so, they would have
been more polished, and the rest of the upper surface would not
have escaped so entirely : perhaps Berendt's explanation fits this
case. A pit near Bredon Railway Station, in the Avon Valley, in
a thick bed of Northern Drift pebbles, yielded only one pebble
that was at all flat-sided. Two, perhaps three, of the sides have
a higher polish than the fourth, and are also more pitted ; they
may have been wind-worn for a short time. A few pebbles that
appear slightly polished, and perhaps facetted, are sent from
Haresfield Camp in the Cottes wolds, at 750 ft. O.D., and from
Cutsdean Hill in the Cotteswolds, at 1,000 ft. O.D. All these
came from the surface of ploughed fields, and we need not
suppose any agent other than the blown dust of the fields.

We may now inquire what light the occurrence of facetted
pebbles in a geological formation throws on the physical con-
ditions of the period. It has been argued that they imply desert
or, at least, steppe conditions. Even so recent a writer as
VVittich (1899), in his careful discussion, says: "Everywhere
Dreikanter occur, are or were similar climatic and geological rela-
tions ; " and, again, " Dreikanter are not found isolated or locally

414 F- A. BATHER ON

confined to small spots, but scattered over wide stretches of
country. The conditions leading to their production must there-
fore have a similarly general significance." The necessary factors
are held by him to be pebble-bearing sand, gravel, or boulder-
clay, slightly or not at all covered with vegetation, a dry climate,
and strong winds. How far these statements are from approach-
ing the truth is shown by the instances of New Zealand, Fjelkinge,
and Watertown. It is, of course, the case that the facetted
pebbles of Germany are scattered over a wide area, and their evi-
dence, in conjunction with that of the Loess, and of the animal
and plant remains found therein, certainly does point to a steppe
period following on the retreat of the glaciers, when the vast plain
was covered with loose deposits as yet uncovered by vegetation
(see Nehring, 1895 ; Sauer, 1890 ; Krause, 1894, and others).
On the other hand the instances of Cuckfield and LugnSs imply
no conditions very different to those now obtaining on the shore
of Liverpool Bay or the beach of Hokitika. Facetted pebbles
are in themselves no evidence of steppes or of a dry climate.
Each case must be considered on its own merits.

Although some of the instances quoted have seemed to imply
certain prevailing winds, yet the observations of Walther and
Stone must always be borne in mind. A large number of speci-
mens must be examined in situ, and their bearings carefully taken
before any opinion can be expressed as to the meteorological
conditions of the locality under investigation. It has been re-
marked that a true Dreikanter at least proves the existence of
three prevailing winds, and that this alone may be a point of
extreme interest. But we have seen that a Dreikanter may be
produced by the action of a single wind, and even that wind may
be very variable within limits. In fine, the only unassailable
conclusion to be drawn from the occurrence of undisturbed
Dreikanter is that the spot was, during their formation, exposed
to subaerial action, and was therefore somewhere above the usual
sea-level. Their occurrence in numbers under beds of sand may
suggest that these latter are subaerial deposits, but is not con-
vincing proof, since a shore exposed for a time to wind action
may softly sink beneath the sea, and its facetted pebbles may be
covered with sand by marine currents. Such seems to have been
the case at Lugnas. This has led Woodworth (1894) to suggest
that pebbles and boulders dredged up should be scrutinised to see
if they bear marks of a^olian erosion, as they would then be
evidence of the sinking of the land.

To return at last to the Bowdon pebble. The beautifully
preserved surface and the clear distinction between the wind-
worn and water-worn portions are evidence enough that this was
not facetted prior to its deposition in the Bunter Beds. On the
contrary, though testimony as to position in the section is wanting,
everything goes to show that it was fashioned on the spot where

WIND-WORN PEBBLES IN THE BRITISH ISLES. 415

it was found. It bears all the characters of a wind-worn pebble :
the facets, the polish, the minute pitting and slight grooving, the
concavity of two facets. But it does not prove the action of more
than two prevalent winds. That these winds were two, and that
they acted for some continuous time, I infer from the fact that
the facets do not coincide with the primitive parallelepipedal
form, or rather with so much of that form as appears to have
remained after its angles had been removed by rolling among the
Bunter pebbles, and again in the glacial drift. The orientation of
the pebble being unknown, nothing can be said as to the direction of
those winds beyond the fact that they were at an angle of 122 deg.
The period when these winds blew cannot have been so remote
from our own day that we have any right to imagine the one of
them (3) to have been any other than the sou'- wester ; and in
that case the other (i) would probably have been about £. by
13 deg. S., and having been the dryer wind had more effect.

One swallow does not make a summer, and one pyramid-
pebble does not imply a dry climate or steppe conditions. Never-
theless it is interesting to note that this specimen bears much
the same relation to glacial deposits and to the subsequent accu-
mulations as do those of Germany and the eastern States of
America. Remains of steppe-animals, though known from the
southern counties, have not, I believe, yet been found in the drift-
deposits of the north of England. The sand is the sole remaining
witness. Unfortunately it is not so easy, as it once was thought,
to distinguish between water-worn and wind-worn sand. Often
all that can safely be said of a sample of sand is that the grains are
large or small, are more or less worn. Carus-Wilson (1892) con-
siders mastoid markings on sand-grains to be undoubted evidence
of aeolian action ; but it is not clear that such markings are in-
evitably present in all blown sands. Mr. Mellard Reade (1892)
describes the sand of the Lancashire and Cheshire Boulder Clay
as " much rounded, some of the grains being extremely polished."
But he finds no difference between the sand of the Crosby dunes
and that of the shore, and therefore regards the sand of the
Boulder Clay as evidence of marine origin. He tells me that he
has examined many sections of Drift all over the country without
noticing evidence of aeolian action. There is room for further
investigation.

The inquiries diligently prosecuted in such time as could be
spared since the Bowdon pebble was placed in my hands nearly a
year ago, have brought to light no startling novelty. But those
who have more opportunity than I for field exploration will doubt-
less find further examples which may lead to more definite con-
clusions. It has been in the hope of inciting others to the search,
and of aiding them in it, that this paper has been drawn up. If
it fails in its object, that will not be the fault of many friends and
colleagues who have helped in its preparation — namely, Dr. Geo.

4l6 F. A. BATHER ON

Abbott, Mr. H. Balfour, Mr. H. Bolton, Canon T. G. Bonney,
Professor G. S. Boulger, Mr. S. S. Buckman, Mr. R. D.
Darbishire, Professor Boyd Dawkins, Professor W. M. Davis, Dr.
C. Gottsche, Mr. Upfield Green, Professor T. Rupert Jones, Mr.
B. Lomax, Mr. A. Mickwitz, Professor A. G. Nathorst, Mr. G. T.
Prior, Mr. Mellard Reade, Mr. C. Davies Sherbom, Mr. L. J.
Spencer, Professor W. W. Watts, and Dr. Henry Woodward. To
all these, and any who may be left unmentioned, I oflfer my
hearty thanks.

REFERENCES.

1855. Blake, W. P. — '* On the grooving and polishing of hard rocks and
minerals by dry sand." Anur. Journ, Set. (2), xx, pp. 178-181.

1855. Ramsay, A. C. — " On the occurrence of angular, subangular,
polished and striated fragments and boulders in the Permian
Breccia of Shropshire, Worcestershire, etc. ; and on the probable
existence of glaciers and icebergs in the Permian Epoch." Quart.
Journ, Geol. 5?c. London^ xi, pp. 185-20$.

1858. GuTBlER, C. A. VON. — " Geognostische Skizzen aus der sachsischen
Schweiz." 8vo. Leipzig. See p. 71 and ff. 84, 85.

i86i. Hitchcock, C. A.—" C5eneral Report on the Geology of Maine." In
Sixth Ann. Rep. Maine Board of Agriculture ^ pp. 146-328. Facetted
pebbles, pp. 266-268 ; cracked, contorted, and impressed pebbles in
conglomerates, pp. 178-185.

1865. Baudissin, a. [Graf]. — *' Bericht ueber die Dunen der Insel Sylt."
Separatabdruck aus der Norddeutscher Zeitung, Flensburg.

1865. GuTBlER, C. A. VON. — [Various blocks supposed shaped by ice-
action, but perhaps wind-worn.] Sitx-ber. a. Ges. Isis^ 1865, pp.
47, 65.

1870. Travers, W. T. L. — "On the sand-worn stones of Evans' Bay."

Trans. New Zealand Inst.^ ii, 247, pi. xvii (April).
1870a. ViRCHOVV, R. — " Lagerstatten aus der Steinzeit in der oberen Havel-

Gegend und in der Nieder-Lausiu." Zeitschr.f. Ethnol.^ ii, pp.

352-358, 2 text-figg.
1870^. . — '* Ueber eine besondere Art geschlififener Steine."

Zeitschr.f. EthnoL, ii, pp. 453, 454.

1871. . — " Geschlififener Steine." Verh. Berlin. Ges.f. Anthrop.,

p. 103, in Zeitschr.f Ethnol.^ iii.

1872. Meyn, L. — " besprach und legte vor 'p)rramidale Geschiebe ' aus

Ilolstein." Zeitschr. deutsch. geol. Ges., xxiv, p. 414.
1874. Credner, H. — " Rine Exkursion der Deutschen Geolo^ischen Gesell-

schaft durch das Sachsische Gebirge." Zeitschr f d. Ges. Naturwiss.,

xliv, pp. 212-222. On pp. 213, 214, Hohburger Porphyrbergen :

groovings, borings, and elevations ascribed to bloAvn sand.
1874, Geiseler (Bauinspecior). — " Polygonaler Steine und eines neuen

Bronzeschwertes." Verh. Berlin. Ges.f Anthrop., p. 128, in Zeitschr.

f. EthnoL, vi.
1874. JOHNSTRUP, J. F. — " Eiendommelig formede RuUesten fra Jylland."

Forhandl. Skand. Naturforsk.. 11 MOde, p. 272.

1874. Reil, W. — " Bearbeiiete Feuersteine von Helvvan (Aegypten)."

Verh. Berlin. Ges. f. Anthrop., pp. 1 1 8-1 20, in Zeitschr. f Etknol., vi.

1875. Gilbert, G. K. — " Report on the geology of portions of Nevada,

Utah, California, and Arizona." Rep, Geogr. and Geol. Explor. W. of
looth Meridian, iii, pp. 17-187. See pp. 82-84, ^"^ pls. viii, ix.

1876. CzEKNY, F. — "Die Wirkungen der VVinde auf die Gestaltung der

Erde." Petermanns Mitt., ErgHnzungsheft 48, iv, & 54 pp., i folding
map. *' Erodirende Wirkung der Winde — die Sandriize," pp. 38, 39.

WIND- WORN PEBBLES IN THE BRITISH ISLES. 417

1876. Meyn, L. — ** Geognostische Beschreibung der Insel Sylt und ihrcr

Umgebung." Ahh. Specialkartt Pieussen^ i, Heft 4. See pp. 636,

637.
1876. Weiss, E. — *' Uebcr concretionSre Gebilde von pyrainidale Gestalt

[aus dcm Vogesensandsleine der Saargegend].'* Zeitsckr, deuisch,

geoi, Ges.. xxviii, p. 416.
1878. Enys, J. D. — "On sand-worn stones from New Zealand.'* Quart,

Journ Geoi. Soc. London^ xxxiv, pp 86-88 (2 woodcuts).

1878. Jones, T. Rupert. — " Sand-worn pebbles in the Wealden of Sussex."

Geoi. Mag. (n.s.), dec. ii, vol. v, p. 287 (June).

1879. ASCHERSON, p.— "Die lybische Waste und ihre Oasen." Ausiand^

Jahrg. 48, Nr. 51, pp. 1004-1009. Nr. 52, pp. 1028-1032.

1879. Penck, a.—" Die Geschiebc -formation Norddeutschlands." Zeitschr-

deutsch, geoi. Ges.y xxxi, pp. 117-203. On p. 154 he says that
Dreikanter are found in Swedish asar, but no locality given, and this
supposed to be a mistake by De Geer.

1880. Herrmann, O. — " Section Pulsnitz." Eriauterung geoi, Speciaikarte

Sacfisen Biatt 52, 50 pp. See pp. 42-45.

1 88 1. De Geer, G.— ** fiJrevisade nagra af honom i Tyskland insamlade

s. k. * Kantensteine ' eller * Pyramidalgeschiebe * och redogjorde fOr
de asigter som uttalats om deras bildningssStt, etc.*' Geoi. Fdren.
Stockkoim Fdr/iandi.^ v, p, 326.

1883. Gottsche, C— " Die Sedimentaer-Geschiebe der Provinz Schleswig-

Holstein.'' 8vo, vi & 66 pp., ii folding-mans. Habilitations-
schrift der UniversitSt Kiel, als MS. gedruckt. Yokohama.

1884. COMMENDA, H.— " RiesentWpfe bci Stejrregg in OberOslerreich."

Verhandi. geoi. Reic/isanst. Wien, 1 884, pp. 308-311.

1884. De Geer, G. — "FOrevisade och beskref nagra prof af vindslipade
stenar fran Skane." Geoi. FOren. Stocitiioim Fdrkandi,^ vi, p. 680.

1884. Keilhack, K. — " Vergleichende Beobachtungcn an islUndischen

Gletscher- und norddcutschen Diluvial-Ablagerunge;i." Jahrit. k.
preuss. geoi. Landes-Anst.^ for 1883, pp. 159-176, J)l. xix. See pp.
172, 173.

1885. Berendt, G. — " Geschiebe-Dreikanter oder Pyramidal-Geschiebe."

Jahrb. ik. preuss. geoi. Landes-Anst.^ for 1884, pp. 201-210, pi. x.
1885. MiCKWiTZ, A. VON— "Ueber Dreikanter im Diluvium bci Reval."
Mit Einleitung von F. Schmidt. Neues Jafirb.y 1885, ii, pp. 177-

179.

1885. Theile, F. — " Die typischen Formen und die Enstehung der

Dreikantner." Uefter Berg und Thai. Organ d. Gehirgsver. f. d.

SachsMm. Sc/tweiz.^ viii, pp. 374 and 382, Nos. 11 and 12. Also ix,

p. 19, 1886 ; and Sits-ber. naturw. Ges. /rw, Jahrg. 1885, pp. 35, 36,

1886
1886a. Blanfori), W. T.— '* Notes on a smoothed and striated boulder from

a Pretertiary deposit in the Punjab Salt Range." Geoi. Mag.

(n.s.), dec. iii, vol. iii, pp 494, 495 (Nov.).
18863. . — " The facetted blocks from the Punjab Salt

Range." Geoi. Mag. (n s.), dec. iii, vol. iii, p. 574 (Dec).

1886. Geinitz, F. E.— "Die Bildung der Kantenger^lle (Dreikanter,

Pyramidalgeschiebe)." Arcfi, Ver. Nat. Mecltienburg^ xl, pp. 33-48,
pis. iii, iv.
1886. Holm, G. — "Bericht ueber geologische Reisen in Ehstland, Nord
Livland und im St.-Petersburger Gouvernement in den Jahren 1883
und 1884." Mem. Soc. Minerai. St. Petersbourg (2), xxii, pp. 1-3 1,
folding- table. Pyramid-pebbles of Reval mentioned on p. 30.

Proc. Geol. Assoc, Vol. XVI, Part 7, May, 1900.] 31

41 8 F. A. BATHER ON

1 886a. Nathorst, a G. — " Uebcr Pjrramidal-Gesteine." Nnus Jakrb. f,

Afin., l886, i, pp. 179, 180.
t886^. . — "Om Kambriska p5rramidalstenar." Ofv.Svtnska

VeUnsk.'Aiad, Fsrhandl., xlii, for 1885, No. 10, pp. 5-17, 4 tcxt-figg.
i886f. . — **0m de Sandslipade stenarnes f5rekomst i de

Kambriska lagren vid Lugnas." Ofv, Svensia Vgtensk.-Akad. Fdr-

handl.^ xliii, for 1886, No. 6, pp. 185-192, 4 text-figg.
1886. Stone, G. H.—"Wind Action in Maine." Amer, J<mm, Sci,(S),

xxxi, pp. 133-138-
188G. WiNCHELL, A.—" Geological Studies; or Elements of Geology for

High Schools, Colleges, Normal, and other Schools." 8vo, xxvi

& 514 pp., Chicago. See p. 284.

1886. Wynne, A. B. — "On a facetted and striated pebble from the Olive

Group conglomerate of Cliel \sic\ Hill in the Salt Range of the
Punjab, India." GeoL Mag, (n.s.), dec. iii, vol. iii, pp. 492-494.

1887. Dames, W. — " [Ueber das Vorkommen von Kantengeschieben unter-

halb des Regensteins bei Blankenburg am Harz ]" Zeitsckr.

dtutsck. geol, Ges.j xxxix, p. 229.
1887. De Geer, G. — "Om vindnOtta stenar." G£o/. Fdren, Stockkolm

Fdrkandl.y viii, pp. 501-513.
1887. Fegraeus, T. — " Sandslipade stenar fran Gotska Sandttn." Geol.

Fdren. Stockkolm Fdrkanal.^ viii, pp. 514-418, pi. vii.
1887. Geinitz, F. E.— " Ueber KantengerOUe." Neues Jakrb. /. Min.,

1887, ii, pp. 78, 79.
1887. MiCKWiTZ, A. VON. — "Die Dreikanter, ein Product des Flugsand-

schliffes, eine Entgegnung auf die von Herm G. Berendt aufge>

stellte Packungstheorie." Mem, Sec, Mintral, St, Peterskourg (2),

xxiii, pp. 82-98, pis. viii, ix.
1887. Oldham, R. D.— " Note on the facetted pebbles from the Olive

Group of the Salt Range, Punjab, India." Geol, Mag, (n.s.), dec. iii,

vol. iv, pp. 32-35 (Jan.)
1887. Staff, F. M. — *• Das untere ! Khuisebthal und sein Strandgebiet."

Verkandl. d. Vereins/. Erdkunde^ Berlin, xiv, pp. 45-66.
1887. Thoulet, J. — Experiences Synthetiques sur I'Abrasion des rochcs

[par la sable]." Compt, Rend. Acad. Set, Paris^ civ, pp 381-383 ;

also Annales des Mines, Mars, Avril, 1887, pp. 199-224.
1887. Wahnschaffe, F — " [Uebcr das Vorkommen von Pyramidal-Geschie—

ben bei Graningen unweit Rathenow]." Zeitsckr. deutsck. geol. Ges.^

xxxix, pp. 226. 227.

1887. Walther, J. — " Die Entstehung von KantengerOUen in der Galala- -

wiiste." Sitz.-Ser. matk.-phys, Classe k. sUcksiscken Ges. Wiss., xxxix,
PP- 133-136 and pi.

1888. Heim, a. — "Ueber Kantergeschiebe aus dem norddeutschen Diluvium." "

Vierteljakrsckr, Zuricher naturf. Ges,^ xxxii, pp. 383-385 [title falsely '
dated 1887].
1888. Wahnschaffe. F.— [Referate ueber Theile 1885, 86, Nathorst
1886/5, Mickwitz 1887, De Geer 1887, Wahnschaffe 1887, Dames -
1887, Walther 1887, und Heim 1888]. Neues Jakrb. f. Min., 1888, .
ii, pp. 300304.

1888. Warth, H.— "A facetted pebble from the Boulder Bed (* speckled^

sandstone ') of Mount Chel in the Salt Range in the Punjab. * Rec,^
Geol. Surv, India^ xxi, pp. 34, 35, ii pis.

1889. Sauek, A. — " Ueber die aolische Enstehung des L(3ss am Rande

Norddeutschen Tiefebene." Zeitsckr./. Naturwiss.. ixii, pp. 326-351-
Seven woodcuts after Walther and Berendt.
1889. Shaler, N. S.— "The Geology of Nantucket." Bull. U.S. Geot^
Survey^ No. 53, 56 pp. X pis. See pp. 21-26, and pi x.

WIND-WORN PEBBLES IN THE BRITISH ISLES. 419

1889. Stone, G. H.— "On the scratched and facetted stones of the Salt

Range. India." Geol. Mag, (n.s.), dec. iii, vol. iv, pp. 415-425
(Sept.) See pp. 420-42 1 on " conditions under which facetting is
done by wind."

1890. RoLLAND, G. — "Chemin de fer transsaharien. Gdolog^ie du Sahara

algerien et aper9U gdologique sur le Sahara de I'oc^an Atlantique k

la Mer Rouge." 410, Pans, text and plates. See 3me Partie, §3.

D^sagrdgation des roches au Sahara, pp. 215-217, pl. xxxi.
1 890. Sauer, a. -*• Zur LOssfrage." Neues Jahrb. f. Afin., 1890, ii, pp. 92-97.

See pp. 96, 97.
1890. AND Chelius, C. — "Die ersten Kanten^feschiebe im

Gebiete der Rheinebene." Neufs Jahrb / Min.^ 1890, li, pp. 89-91.

1890. Weber, E. — "Section Radeberg.'* ErlAuterung geol. Specialkarte

Sachsetty Blatt 51, 40 pp. See p. 36.

1 891. Chelius C— "Blatt MOrfelden." ErlOut. x. geol. Karte d. Gross-

herzogthums Hesse. Lief. ii. See pp. 16, 17.

1891. Walther, J.— "Die Denudation in der Wuste und ihre Geologische

Bedeutung u.s.w." Ahhandl. k, idchsischen Ges. d. Wiss.^ xxvii,
pp. 345-570, viii pis. See pp. 445-448.

1892. Carus-Wilson, C. — " Shapes of Sand grains. Flexible Sandstone."

Geol. Mag. (n.s.), dec. iii, vol. ix, pp. 429, 430 (Sept.Y
1892. Chelius, C. — " Flugsand auf Kheinalluvium und zur Jetztzeit."

Neues Jahrb,/. Min.^ 1892, i, pp. 224-226.
1892. Rbade, T. Mellard. — "Glacial Geology: Old and New." GeoL
Mag. (n.s.), dec. iii, vol. ix, pp. 310-321 (July). *' Shapes of Sand-
grains," torn, cit.fjip. 478-479 (Oct.).

1892. WAHNSCHAFFE, F.— " Beitrag zur LOssfrage," Jahrb. A. preuss.

geol. Landesanst.^ for 1889, pp. 328-346, 2 text-figg. See pp. 331-
333.

1893. Salisbury, R. D.— [In " Report on Surface Geology."] Ann. Rep.

New Jersey Geol. Survey for 1892. See p. 155.

1894. Chelius, C. und Klemm, G. — " Blatt Neustadt-Obemburg." Erldut

z. geol. Karte d. Groisherzogthums Hesse^ Lief. iii. See p. 13.
1894. Davis, W. M —"Facetted pebbles on C. Cod, Mass." Froc. Boston

Soc. Nat. Hist.y xxvi, pp. 166-175, P^^- ^ i^* Abstract, and discussion

by G. K. Gilbert and N. S. Shaler. Amer. Geol.^ xiii, pp. 146,

147 (Feb. 1894).
1894. GoLDSCHMiDT, V. — " Ueber Wustenstcine und Meteoriten."

Tschermaks min, petrogr. Mitth.^ xiv, Heft 2 pp. 131-142, pis. iii

and iv.
1894. Krause, E. H. L.— " Die Steppenfrage." Globus, Ixv., pp. 1-6.

1894. WooDWORTH, J. B. — "Post-Glacial eolian action in southern New

England." Amer. Journ. Set. (3), xlvii, pp. 63-71.

1895. Nehring, a. — " Ursachen der Steppenbildung in Europa." Geogr.

Zeitschr., i, pp. 152-163.

1895. Obruchev, V. — "O protzessakh v 'ivyetrlvan'ya I razduvaniya v

Tzentral'noi Azil." (The processes of weathering and deflation in
Central Asia.) Verh. mineral. Ges. St. Petersburg (2), xxxiii, pp. 229-
272, pis. iv-vii. All in Russian. Facetted pebbles are among the
objects figured.

1896. Andersson, J. GuNNAR. — " Mellan haf och dyner (Gotska

sandon)." Sx<enska Turistforeningens Arsskrift, 1 895.
1896. Baltzer, a.— " Vom Rande der Wuste." Mitth. naturf. Ges, Btrn.,

a.d. Jahre, 1895, pp. 13-37, iii pls.
1896. FkCH, J. — " Ueber Windschliffe am Laufen bei Laufenburg am

Rhein." Globus, Ixvii, No. 8.
1896. Noetling, F.— "Beitrage zur Kenntniss der glacialen Schichten

permischen Alters in der Salt Range, Punjab (Indien)." Neues

Jahrb./, Mm., 1896, ii, pp. 61-86, pl. v.

420 PROCEEDINGS,

1896. Verworn, Max.— **Sandschliffe vom Djcbcl Nakfts. Ein Beitrag

zur Entwicklungsgeschichte dcr KanlengerOlle. Nnus Jakrb. J

Min,y 1896, i, pp. 200-2 ro, pi. vi.
1898 (? 9). Emerson, B. K. — "Geology of Old Hampshire Comity,

Massachusetts, etc." U.S. GeoL Survey Monogr. xxix, xxi & 790 pp.|

3S pis. See p. $34-

1898. Udden, J. A.— "The Mechanical composition of Wind deposits."

Augusiana Library ^ Publ. No. I, 69 pp. Analyses sizes of grains in
deposits, from *' Lag gravels " to the finest atmosphenc dust.
Discusses acolian origin of Loess.

1899. Bathf.r, F. a. — [exhibited and remarked on a pebble found at

Bowdon]. Quart Joum. Geol. Soc, Iv, p. xc, PROCEEDINGS of
June 7th.
1899. Lapparent, a. I)E.— " Traite de G^logie," Ed. 4, 1900 {sic) ; p. 140.

1899. WiTTlCH, Ernst. -—*' Ueber Dreikanter aus der Umgegend von

Frankfurt." Ber, Senckmbergischen naturf, Ges. Frankfurt 1898,
pp. 173-189, pis. V, vi.

1900. Watts, W. Vv.— ♦• Notes on the surface of the Mount Sorrel Granite.**

Rep. Brit, Assoc., 1899, p. 747.

Explanation of Plate XL

Figs. 1-4.— From Reval, Esthonia. 1-3 placed in the same orientation as
when found. North (magnetic, August, 1897) at the top of the page.

Fig. I. — Fine-grained hornblende gneiss : a, uoper surface, all worn and
pitted, with clear-cut facet on south, lichen growing on the lower
slopes ; b. under surface, water-worn and iron-stained.

Fig. 2. — Augen-gneiss : upper surface, the quartz standing out in ridfM
around the rolled orthoclase, the mica eaten away ; the south-waft
side lies almost in the plane of the foliation, so that the ridginf ii
confined to the other two sides ; the apex is obliquely truncated ; iH
depressions overgrown by lichen. Cf. Diagr. 3, p. 408.

F'iG. 3. — A very fine-grained hornblende gneiss : upper surface much polished,
with a few slight elevations of quartz ; lichen on the lower slopes,
forming a band between the wind-worn and water-worn surfaces.

Fig. 4.- Granite, very slightly foliated, but not enough to produce ridging;
upper surface, all polished and dififerentiated ; apex obliquely
truncated.

Fig. 5.— From Hokitika beach. South Island, New Zealand. Basalt : upper
surface showing two main facets and a truncate end ; slight furrows
cross the stone at right angles to the main ridge.

Fig. 6. — From Bowdon, Cheshire, in Drift. Liver-coloured quartzite derived
from Bunter Pebble Beds : a, upper surface, showing facets ; b. under
water- worn surface. C/. Diagr. i and 2, p. 397.
All figures are x ' diam.

ORDINARY MEETING.

Friday, May 4TH, 1900.

W. Whitaker, B.A., F.R S, President, in the Chair.

Thomas P. Baldwin, Miss Grace Hacking, B.Sc, Harford J.
Lowe, J. B. Morris, Miss E. Pearse, B.Sc, were elected membe^
of the Association.

A lecture was delivered by Mr. Horace W. Monckton, F.L.&,
F.G.S., on *• Some Features of the Recent Geology of Western
Norway," illustrated by lantern slides.

C. Chubb photogr

WIND-WORN PEBBLES.

Hot«.^tv &. YiaAA <«J\'c*^

4l6 F. A. BATHER ON

REFERENCES.

1855. Blake, W. P. — " On the grooving and polishing of hard rocks and
minerals by dry sand." Anur. Journ, Set. (2), xx, pp. 178-181.

1855. Ramsay, A. C. — " On the occurrence of angular, subangular,
polished and striated fragments and boulders in the Permian
breccia of Shropshire, Worcestershire, etc. ; and on the probable
existence of glaciers and icebergs in the Permian Epoch." Quart,
yourn. Geol. 5?c. London^ xi, pp. 185-205.

1858. GiiTBlER, C. A. VON.— " Geognostische Skizzen aus der sUchsischen
Schweiz." 8vo. Leipzig. See p. 71 and fF. 84, 85.

1861. Hitchcock, C. A.—" C5eneral Report on the Geology of Maine.'* In
Sixth Ann. Rep. Maine Board of Agriculture^ pp. 146-328. Facetted
pebbles, pp. 266-268 ; cracked, contorted, and impressed pebbles in
conglomerates, pp. 178-185.

1865. Baudissin, A. [Graf]. — *' Bericht ueber die Diinen der Insel Sylt."
Separatabdruck aus der Norddeutscher Zeitung, Flensburg.

1865. GuTHiEK, C. A. VON. — [Various blocks supposed shaped by ice-
action, but perhaps wind-worn.] Siiz-6fr. d. Ges. Isis^ 1865, pp.
47, 65.

1870. Travers, VV. T. L. — "On the sand-worn stones of Evans' Bay."
Trans. New Zealand Inst.^ ii, 247, pi. xvii (April).

1 870a. ViRCHOW, R. — " Lagerstaiten aus der Steinzeit in der oberen Havel-
Gegend und in der Nieder-Lausitz." Zeitschr. f. Ethnol.^ ii, pp.
352-358, 2 text-figg.

1870/5. . — " Ueber eine besondere Art geschliffener Steine."

Zeitschr. f. Ethnoi., ii, pp. 453, 454.

1871. . — "Geschlififener Steine." Verh. Berlin. Ges. f. Anthrop.^

p. 103, in Zeitschr. f. Ethnol.y iii.

1872. Meyn, L. — '* besprach und legte vor ' pynimidale Geschiebe ' aus
Ilolstein." Zeitschr. deutsch. geol. Ges.^ xxiv, p. 414.

1874. Credner, H. — " Eine Exkursion der Deutschen Geologischen Gesell-
schaft durch das Sachsische Gebirge." Zeitschr/. d. Ges. Naturwiss.^
xliv, pp. 212-222. On pp. 213, 214, Hohburger Porphyrbergen :
groovings, borings, and elevations ascribed to blown sand.

1874. Geiseler (Bauinspector). — " Polygonaler Steine und eines neuen
Bronzeschwertes." Verh. Berlin. Ges./. Anthrop.^ p. 128, in Zeitschr.
/. Ethnol.^ vi.

1874. JoHNSTRUP, J. F. — " Eiendommelig formede RuUesten fra Jylland."
Forhandl. Skand. Natur/orsk.. 11 Mode, p. 272.

1874. Reil, W. — " Bearbeitete Feuersteine von Ilehvan (Aegypten).'*

Verh. Berlin. Ges. /. Anthrop., pp. 1 1 8-1 20, in Zeitschr./. Ethnol.^ vi.

1875. Gilbert, G. K. — " Report on the geology of portions of Nevada,

Utah, California, and Arizona." Rep. Geogr. and Geol.Explor. \V. of
looth Meridian^ iii, pp. 17-187. See pp. X2-84, and pis. viii, ix.

1876. Czerny, F. — " Die Wirkungen der Winde auf die Gestaltung der

Erde." Petermanns Mitt.., Ergdnzungshe/t 48, iv, & 54 pp., i folding
map. *' Erodirende VVirkung der Winde — die Sandritze," pp. 38, 39.

WIND-WORN PEBBLES IN THE BRITISH ISLES. 417

1876. Meyn, L. — " G«ognostische Beachreibung der Insel Sylt und ihrer

Umgebung." A6A. Specialkartt Pieusstn^ i, Heft 4. Sec pp. 636,

637.
1876. Weiss, E.— " Uebcr concretionSre Gcbildc von pyrainidale G«stalt

[aus dem V^ogesensandsteine der Saargegend].** Zeitsckr. deutsck,

geol. Gn.. xxviii, p. 416.
1878. Enys, J. D.— "On sand-worn stones from New Zealand.** Quart,

Journ Geol, Soc. London^ xxxiv, pp 86-88 (2 woodcuts).

1878. Jones, T. Rupert.—" Sand- worn pebbles in the Wealden of Sussex.*'

GeoL Mag. (n.s.), dec. ii, vol. v, p. 287 (June).

1879. AsCHERSON, p. — "Die lybischc Wuste und ihre Oasen." Auslandy

Jahrg. 48, Nr. 51, pp. 1004-IOO9. Nr. 52, pp. 1028-1032.

1879. Penck, a. — " Die Geschiebe-fonnation Norddeutschlands." Zeitsckr-

deutsck. geol, Ges.^ xxxi, pp. 117-203. On p. 154 he says that
Dreikanter are found in Swedish asar, but no locality g^ven, and this
supposed to be a mistake by De Geer.

1880. Herrmann, O— " Section PulsniU.** Erlauterung geoL SpecialkarU

Sacksen Blatt 52, 50 pp. See pp. 42-45.

1 88 1. De Geer, G.— ** f5revisade nagra af honom i Tyskland insamlade

s. k. * Kantensteine * eller * Pyramidalgeschiebe * och redogjorde fttr
de asigter som uttalats om deras bildningssiitt, etc.*' Geol. Fdren.
Stockholm Fdrkamdl., v, p, 326.

1883. GOTTSCHE, C— '* Die Sedimentaer-Geschiebe der Provinz Schlcswig-

Holstein.** 8vo, vi & 66 pp., ii folding-mans. Habilitations«
schrift der Universitiit Kiel, als MS. gedruckt. Yokohama.

1884. COMMENDA. H.— " Riesentttpfe bei Stejrrcgg in OberOslerreich."

Verkandl. geol. Reicksanst. Wien^ 1884, pp. 308-311.

1884. De Geer, G. — "FOrevisadc och beskref nagra prof af vindslipade
stenar fran Skane." Geol. FOren. Stockkolm Fdrkandl., vi, p. 680.

1884. Keilhack, K.— '* Vergleichende Beobachtungcn an islUndischen

Gletscher- und nordoeutschen Diluvial- Ablagerunge.i." Jahrh. k.
preuss. geol. Landes-Anst.^ for 1883, pp. 159-176, j)l. xix. See pp.
172, 173.

1885. Berendt, G. — " Geschiebe-Dreikanter oder Pyramidal-Geschiebe."

Jahrb. k. preuss. geol. Landes-Anst., for 1884, pp. 201-210, pi. x.
1885. MiCKWiTZ, A. VON— "Ueber Dreikanter im Diluvium bei Reval."
Mit Einleitung von F. Schmidt. Neues Jahrb.^ 1885, ii, pp. 177-

179.

1885. Theile, F. — " Die typischen Formen und die Enstehung der

Dreikantner." Ueher Berg und Thai. Organ d. Gebirgsver. f. d.

SachsUkm. Sckweiz.^ viii, pp. 374 and 382, Nos. 11 and 12. Also ix,

p. 19, 1886; and Sitz-ber. naturw. Ges. Isis^ Jahrg. 1885, pp. 35, 36,

1886
1886a. Blanfori), W. T. — " Notes on a smoothed and striated boulder from

a Pretertiary deposit in the Punjab Salt Range." Geol. Mag.

(n.s.), dec. iii, vol. iii, pp 494, 495 (Nov.).
1886^. . — "The facetted blocks from the Punjab Salt

Range." Geol. Mag. (n s.), dec. iii, vol. iii, p. 574 (Dec).

1886. Geinhz, F. E.— "Die Bildung der Kantenger/Jlle (Dreikanter,

Pyramidalgeschiebe)." Arck, Ver. Nat. Mecklenburg^ xl, pp. 33-48,
pis. iii, iv.
1886. Holm, G. — "Bericht ueber geologische Reisen in Ehstland, Nord
Livland und im St.-Petersburger Gouvernement in den Jahren 1883
und 1884." Mem. Soc. Mineral St. Petersbourg (2), xxii, pp. 1-31,
folding-table. Pyramid-pebbles of Reval mentioned on p. 30,

Proc. Geol. Assoc., Vol. XVI, Part 7, May, 1900.] 31

4l8 F. A. BATHER ON

l886tf. Nathorst, a G.— " Ueber Pyramidal-Gesteine." Ntues Jakrb. f,

Min,^ 1886, i, pp. 179, 180.
t886^. . — "Om Kambriska pjrramidalstenar." Ofv. Svenska

Vetensk.'Akad, FSrhandL, xlii, for 1885, No. 10, pp. 5-17, 4 text-figg.
i886f. . — "Om de Sandslipade stenarnes f5rekomst i dc

Kambriska lagren vid Lugnas." Ofv, Svenska Vetensk.-Akad, Fcr-

handl., xliii, for 1886, No. 6, pp. 185-192, 4 text-figg.
1886. Stone, G. H.— "Wind Action in Maine." Amer, Journ, Sa.ii),

xxxi, pp. 133-138.
1886. WiNCHELL, A.—" Geological Studies; or Elements of Geology for

High Schools, Colleges, Normal, and other Schools." 8vo, xxvi

& 514 pp., Chicago. See p. 284.

1886. Wynne, A. B. — "On a facetted and striated pebble from the 01i?c

Group conglomerate of Cliel [sic] Hill in the Salt Range of the
Punjab, India." Geo/, Mag, (n.s.), dec. iii, vol. iii, pp. 492-494.

1887. Dames, W. — *' [Ueber das Vorkommen von Kantengeschieben unter-

halb des Regensteins bei Blankenburg am Harz ]" ZeitscAr,

deutsch. geol. Ges.y xxxix, p. 229.
1887. De Geek, G. — "Om vindnOtta stenar." Geo/, Fdren, Stockko/m

Fdrhand/.^ viii, pp. 501-513.
1887. Fegraeus, T. — " Sandslipade stenar fran Gotska SandOn." Geo/.

Fdren, Stockho/m Fdrhand/.^ viii, pp. 5 14-4 1 8, pi. vii.
1887. Geinitz, F. E.— '* Ueber KantengerOlle." Neues Jakrb, /. Afm,^

1887, ii, pp. 78, 79.
1887. MlCKWiTZ, A. VON. — "Die Dreikanter, ein Product des Flugsand-

schliffes, eine Entgegnung auf die von Herrn G. Berendt aufge-

stellte Packungstheorie." Mem. Sec. Mimra/. St. Peter sbourg (2),

xxiii, pp. 82-98, pis. viii, ix.
1887. Oldham, R. D. — " Note on the facetted pebbles from the Olive

Group of the Salt Range, Punjab, India." Geo/, Mag. (n.s.), dec. iii,

vol. iv, pp. 32-35 (Jan.)
1887. Stapf, F. M. — "Das untere ! Khuisebthal und sein Strandgebiet."

Verhand/, d. Vereinsf. Erdkunde^ Ber/in. xiv, pp. 45-66.
1887. Thoulet, J. — Experiences Synthetiques sur I'Abrasion des roches

[par la Siible]." Compt. Rend. Acad. Sci. Faris^ civ, pp 381-383 ;

also Anna/es des Mines^ Mars, Avril, 1887, pp. 199-224.
1887. Wahnschaffe. F — " [Ueber das Vorkommen von Pyramidal-Geschie-

ben bei Graningen unweit Rathenow]." Zeitschr. deutsck, geo/. Ges.^

xxxix, pp. 226, 227.

1887. Walther, J. — " Die Entstehung von KantengerOUen in der Galala-

wiiste." Sitz.-ber, math,-p/iys, C/asse k. siicfisiscken Ges, Wiss.^ xxxix,
PP- 133-136 and pi.

1888. Heim, a. — "Ueber Kantergeschiebe aus dem norddeutschen Diluvium."

Vierte/jakrsckr, Zuricher nalurf. Ges,y xxxii, pp. 383-385 [title falsely
dated 1887].
1888. Wahnschaffe. F.— [Referate ueber Theile 1885, 86, Nathorst
1886/5, Mickwitz 1887, De Geer 1887, Wahnschaffe 1887, Dames
1887, Walther 1887, und Heim 1888]. Neues Jahrb. f, Min., 1888,
ii, pp. 300-304.

1888. Warth, H.— "A facetted pebble from the Boulder Bed ('speckled

sandstone ') of Mount Chel in the Salt Range in the Punjab. * Rec,
Geol. Surv. Indta^ xxi, pp. 34, 35, ii pis.

1889. Sauek, a. — " Ueber die aolische Enstehung des L(5ss am Rande der

Norddeutschen Tiefebene." Zeitschr./. Naturwiss.. Ixii, pp. 326-351.
Seven woodcuts after Walther and Berendt.
1889. Shaler, N. S.— "The Geology of Nantucket." Bu//. U.S. Geot.
Survey^ No. 53, 56 pp. x pis. See pp. 21-26, and pi x.

WIND-WORN PEBBLES IN THE BRITISH ISLES. 419

1889. Stone, G. H.— "On the scratched and facetted stones of the Salt

Range. India." Geol. Mag. (n.s.), dec. iii, vol. iv, pp. 415-425
(Sept.) See pp. 420-421 on "conditions under which facetting is
done by wind. '

1890. RoLLAND, G. — "Chemin de fer transsaharien. G^ologie du Sahara

algerien et aper^u gdologique sur le Sahara de Toc^an Atlantique k

la Mer Rouge." 4to, Paris, text and plates. See 3me Partie, §3.

D^sagr^gation des roches au Sahara, pp. 215-217, pi. xxxi.
1890 Sauer, a. — " Zur LOssfrage." Neues Jahrb. f. Min.^ 1890, ii, pp. 92-97.

See pp. 96, 97.
1890. AND Chelius, C. — "Die ersten Kantengeschiebe im

Gebiete der Rheinebene." Neues Jahrb f, Min.^ 1890, ii, pp. 89-91.

1890. Weber, E. — "Section Radeberg.** Erl&uterung geol. Specialkarte

Sachsen^ Blatt 51, 40 pp. See p. 36.

1 891. Chelius C— "Blatt Marfelden." Erl&ut. x. geol. Karte d. Gross-

herzogthums Hesse. Lief. ii. See pp. 16, 17.

1891. Walther, J. — " Die Denudation in der Wiiste und ihre Geologische

Bedeutung u.s.w." Abhandl. i. i&chsischen Ges. d. Wiss,^ xxvii,
pp. 345-570, viii pis. See pp. 445-448.

1892. Carus-Wilson, C. — "Shapes of Sand grains. Flexible Sandstone."

Geol. Mag. (n.s.), dec. iii, vol. ix, pp. 429, 430 (Sept.).

1892. Chelius, C. — " Flugsand auf Kheinalluvium und zur Jetztzeit."
Neues Jahrb. f. Min.^ 1892, i, pp. 224-226.

1892. Reade, T. Mellard— -"Glacial Geology: Old and New." Geol.
Mag. (n.s.), dec. iii, vol. ix, pp. 310-321 (July). *' Shapes of Sand-
grains," torn, cit.ypp. 478-479 (Oct.).

1892. WahnscHAFFE, F.— " Beitrag zur LOssfrage." JaArb. i. preuss.

geol. Landesanst.^ for 1889, pp. 328-346, 2 text-figg. See pp. 331-
333.

1893. Salisbury, R. D— [In " Report on Surface Geology."] Ann. Rep,

New Jersey Geol. Survey for 1 892. See p. 155.

1894. Chelius, C. und Klemm, G. — " Blatt Neustadt-Obemburg.'' Erlaut,

z. geol. Karte d. Grossherzogihums Hesse ^ Lief. iii. See p. 13.
1894. Davis, W. M— "Facetted pebbles on C. Cod, Mass," P roc. Boston

Soc. Nat. Hist.y xxvi, pp. 166-175, pis. i, ii. Abstract, and discussion

by G. K. Gilbert and N. S. Shaler. Anur. Geol.^ xiii, pp. 146,

147 (Feb. 1894).
1894. Goldschmiut, v. — " Ueber Wustensteine und Meteoriten."

Tschermaks min. petrogr. Mitth.^ xiv. Heft 2 pp. 1 31-142, pis. iii

and iv.
1894. Krause, E. H. L. — " Die Steppenfrage." Globus, Ixv., pp. 1-6.

1894. Woodworth, J. B. — " Post-Glacial eolian action in southern New

England." A mer. Journ. Set. (3), xlvii, pp. 63-71.

1895. Nehring, a. — " Ursachen der Steppenbildung in Europa." Geogr,

Zeiischr., i, pp. 152-163.

1895. Obruchev, V. — "O protzessakh v 'ivyetrivan'ya i razduvani)ra v

Tzentral'nol AziL" (The processes of weathering and deflation in
Central Asia.) Verk. mineral. Ges. St. Petersburg (2), xxxiii, pp. 229-
272, pis. iv-vii. All in Russian. Facetted pebbles are among the
objects hgrured.

1896. A.NDERSSON, J. GuNNAk. — " Mellan haf och dyner (Gotska

sandon)." Si'enska Turistforeningens Arsskrtft, 1895.
1896. Baltzer, a.— " Vom Rande der Wiiste." Mitth. naturf. Ges. B*rn.,

a.d. Jahre, 1895, pp. 13-37, ii' pls.
1896. FrCh, J. — " Ueber Windschliffe am Laufen bei Laufenburg am

Rhein." Globus, Ixvii, No. 8,
1896. NOETLING. F.— "Beitrage zur Kenntniss der glacialen Schichten

permischen Alters in der Salt Range, Punjab (Indien)." Neues

Jahrb. f. Mm., 1896, ii, pp. 61-86, pi. v.

420 PROCEEDINGS,

1896. Verworn, Max.— »*Sandschliffe vom Djcbel Nakfts. Ein Beitrag

zur Entwicklungsgcschichtc dcr KantengerUlle. NiUis Jttkrb. }

Afin.y 1896, i, pp. 200-2 K>, pi. vi.
1898 (? 9). Emerson, B. K. — "Geology of Old Hampshire County,

Massachusetts, etc." U.S, Geol. Survey Monogr. xxix, xxi & 79© PP«*

3S pis. See p. 534.

1898. Udden, J. A.— "The Mechanical composition of Wind deposiu.'

AugHstana Library^ Publ. No. I, 69 pp. Analyses sizes of ^ins in
deposits, from ** Lag gravels " to the finest atmosphenc dust.
Discusses aeolian origin of Loess.

1899. Bather, F. A.— [exhibited and remarked on a pebble found at

Bowdon]. Quart, Joum. GeoL Soc, Iv, p. xc, PROCEEDINGS of
June 7lh.
1899. Lapparent, A. DE.— " Traite de Geologic," Ed. 4, 1900 {sic) ; p. 140.

1899. WiTTiCH, Ernst. — •' Ueber Dreikanicr aus der Umgegcnd von

Frankfurt." Ber, Senclunbergischin naturf, Gis. FrankfurU 1898,
pp. 173-189, pis. V, vi.

1900. Watts, W. Vv.— •• Notes on the surface of the Mount Sorrel Granite,**

Rip. Brit, Assoc. ^ 1899, p. 747.

Explanation of Plate XL

Figs. 1-4.— From Reval, Esthonia. 1-3 placed in the same orientation as
when found. North (magnetic, August, 1897) at the top of the page.

Fig. I. — Fine-grained hornblende gneiss : a, uoper surface, all worn and
pitted, with clear-cut facet on south, lichen growing on the lower
slopes ; h. under surface, water-worn and iron-stained.

Fig. 2. — Augen-gneiss : upper surface, the quartz standing out in ridges
around the rolled orthoclase, the mica eaten away ; the south-west
side lies almost in the plane of the foliation, so that the ridging is
confined to the other two sides ; the apex is obliquely truncat«l ; all
depressions overgrown by lichen. Cf. Diagr. 3, p. 408.

F'IG. 3. — k very fine-grained hornblende gneiss : upper surface much polished,
with a few slight elevations of quartz ; lichen on the lower slopes,
forming a band between the wind-worn and water-worn surfaces.

P^IG. 4.- Granite, very slightly foliated, but not enough to produce ridgine ;
upper surface, all polished and differentiated ; apex obliquely
truncated.

Fig. 5.— From Hokitika beach. South Island, New Zealand. Basalt : upper
surface showing two main facets and a truncate end ; slight furrows
cross the stone at right angles to the main ridge.

Fig. 6. — From Bowdon, Cheshire, in Drift. Liver-coloured quartzite derived
from Bunter Pebble Beds : a, upper surface, showing facets ; b, under
water-worn surface. Cf. Diagr. I and 2, p. 397.
All figures are x 3 diam.

ORDINARY MEETING.
Friday, May 4TH, 1900.

W. Whitaker, B.A., F.R S, President, in the Chair.

Thomas P. Baldwin, Miss Grace Hacking, B.Sc, Harford J.
Lowe, J. B. Morris, Miss E. Pearse, B.Sc, were elected members
of the Association.

A lecture was delivered by Mr. Horace W. Monckton, F.L.S.,
F.G.S., on " Some Features of the Recent Geology of Western
Norway," illustrated by lantern slides.

Gilbert C Cbabb photogr

W/ND-WOKN PEBBLVS

NVm\^*^\\ ^ ¥.VV

421

A NEW RHiETIC SECTION AT BRISTOL.

By W. H. WICKES.

{Read January jM, iqoo.)

IN 1 89 1 the late Edward Wilson described a ne^ section at
Pylle Hill, Bristol, and stated that: "Although the
Rhietic rocks have a wide horizontal distribution in the neigh-
bourhood of Bristol, it is but seldom that they are exposed at the
surface. In the absence of natural inland sections, and of
quarries on the horizon of a thin series of rocks which yield no
minerals of commercial value, we have generally to trust to new
railway cuttings or other artificial excavations for affording us
opportunities for their examination." " A redescription of the
Pylle Hill section therefore appears desirable whilst it is in a
fresh state. In a very short time the new cutting, which, like the
old one, is sloped at so high an angle as to be almost in-
accessible, will become obscured by rain-wash and vegetation, and
thus be no longer available for detailed examination."*

The foregoing remarks so accurately represent the state of
the Kha:tic Beds in Bristol and its suburbs, as to make them
worth quotation. All the sections hitherto described are now
built upon or otherwise inaccessible. It is therefore thought that
a description of a new section may be of interest. Some fields to
the north of Bristol, near Redland Green (about 2\ miles north-
west of the Pylle Hill cutting), have been lately laid out for
building purposes under the name of ** New Clifton," and a low
hill, on which Coldharbour Farm stands, has been cut through
for the main road, exposing Lower Lias, Rhaetic, and Upper
Trias Beds. The two first are well exposed, but the dip is
difficult to determine owing to slight anticlinals which give the
beds a wavy appearance. It is believed, however, that the beds
dip about 2 or 3 deg. to the N.N.VV. The cutting is from 5 to
7 ft. in height, and is on a slope. By measuring at several points
the following section has been obtained :

REDLAND (New Clifton) SFXTION.

ft. in.

2 A ( Six Beds of hard Limestone
^ ^ -, with clay partings

^"-^ ( 7 Rubbly Limestone

t- r. f/^Vhile shaly Limestone, with
^ < -[ occasional seam of hard

> ~ I conchoidal Limestone

0 Clay parting ....

3 O
O 7

o 9

o 1.1

^ AmmoniUs pianorlis^ A. jo/in-
I ^ioni^ Oslrea iiassica. Pen la-

crinus^ PUuromya^ Nautilus
striatus^ Cidaris spines.

Monotis decHssatuSy Modiola
minima.

* Quart Joum. Ceol. Soc.^ 1891, vol. xlvii, p. 545.

Pkoc. Gfol. Assoc, Vol. XVI, Part 7, May, 1900.]

422 W. H. WICKES ON A NEW RHiETIC SECTION AT BRISTOL.

n Compact conchoidal Lime-
stone, with " Landscape "
Markings (Gotham Marble)
m Laminated blue and brown
clay (weathering greenish-
grey), with two white cal-
careous bands, and some
dark-brown septaria .

/ Cream-coloured shaly Lime-

k stone, with blue core and
occasional greenish - grey
septaria ....

f Dark bluish-green crystalline
Limestone

h Dark brown and black sha'y
clay

ft. in.

O 8

1 ^Dark crystalline Limestone

o 8

o 5

o 4

3 o

JModiola minima and small
turbinate Gastcropod (un-
determined).

\^ertebra of Plesicsaurus^ small
Ostracods (^Darwinuia /).

Fish remains, teeth, and scales
of SauricthySy GyroUpis, Pholiy
dophorusy Insect wings,^jM/r/a
minuta^Darwinula UgumineOaf
Pectin vaioniensis^ Cardium
rhcpiicum^Naiadites acuminatus.

JAvicuIa contorta^ Pecten valoni-
ensis,
Axinus cloadnus.
Cardium rkceticum.

/Black shales and clay

Base of section. The black shales probably go down another

sft.

The Tea-green and Red Marls crop out a short distance away,
but the junction is not at present opened up.

Of the sections previously recorded, that of "Pylle Hill,"
described by E. Wilson, most nearly resembles this one, therefore
the marginal letters used by him in specifying the various beds,
have been added for purposes of identification and comparison.

Owing to the thinning out of some of the beds, and also to
changes in the composition of others, this correlation in some
cases is only approximate. Mr. Wilson's section shows 17 ft. of
Rhaetic beds at Pylle Hill. This section (allowing for 5 ft. unex-
posed) gives only about 14 ft., the principal loss occurring in bed
" w," which measures 2 ft. as against 4 ft. 11 in. in E. Wilson's
section.

Many of the beds are of the usual Rhaetic character and
require no special comment, but the bed "^" is interesting,
being in some zones full of the little water plant Naiadites
acuminatus in a fine state of preservation.* In the same bed
occur two or three layers of crushed shells (principally Cardium
rhceticum), amongst which are found fragmentary elytra of
beetles. In many cases these are only casts, the original chiton
having disappeared. One seems to be a larval form, probably of
a Lampyrid beetle. In the same bed parts of a head of a fish,
referred to Fholidophorus by Mr. Smith Woodward, have been
noted.

There does not appear to be any definite " bone-bed " as at
Aust Cliff, but teeth and scales of fish are scattered through the
section. At some horizons they are more plentiful, but bones are
rare, and when found are very minute.

The bed " «," of Gotham Marble, is the best development

* Mr. A. C. Sttward has kindly pruniiscd lo c.\ainin« this new material.

VISIT TO THE GEOLOGICAL SOCIETY'S MUSEUM. 423

the writer has seen of this curious rock, some hundreds of blocks
having been exposed in the excavation. The thickness is unusual,
varying from 4 to 1 1 in. Many of the larger blocks have double
" landscapes." One of these has been polished, with very satis-
factory results, and is now in the Museum of Practical Geology.
Nearly all the rest, however, have been used for road-making.

The list of fossils given in this section could easily be ex-
tended, as many are still undetermined, but it was thought
advisable to record only such as were well defined and
recognisable.

In certain parts of these beds — usually lining crevices in the
rocks — small portions of the rare mineral known as "Baryto-
Celestine'* occur. It is usually in a decomposed state and
breaks up into a fine powder. Some distance from the section
a small deposit was found by the writer containing some very
good unweathered crystals, but the bed is now worked out.
This rare mineral was noted by Dr. Norman Collie as occurring
in the Trias, near Clifton Down Station, some twenty years ago.*
It does not appear to have been noticed since. Last year the
writer found some small pieces in the Trias, and also traces of it
in the Millstone Grit of Clifton, but it has not been noted,
hitherto, from the Rhaetic. It is reported that Bristol is the only
British locality.

'* Baryto-Celestine," apart from its chemical composition,
differs from ordinary " Celestine *' in the following characters :
Its crystals are mostly opaque, but occasionally transparent,
radiate, or divergent, the angles obscure. It is much more
brittle than the true celestine, weathers to a soft, powdery sub-
stance, almost as fine as Fuller's P2arth, but which still shows the
radiate structure. It occurs in cracks and fissures, and is
evidently a secondary deposit.

VISIT TO THE MUSEUM OF THE GEOLOGICAL
SOCIETY OF LONDON.

Saturday, February ioth, 1900.
Director : C. Davies Sherborn.

{^Report by the DIRECTOR.)

A LARGE party having assembled in the Museum, the Director
pointed out that the collection dated from 1807, and had been
slowly accumulating until about ten years ago, when pressure of
space had prohibited further additions. The collection con-
sisted of figured types, specimens referred to in the Society's

•See Ptoc. Bristol Naturalists' Soc. (N.S.), vol. ii, 1879, P* 292 ; also th^ Minerahgical
Magazine, vol. ii, 1879, p. 220.

Pkoc. Geol. Assoc, Vol. XV'I, Part 7, Mav, 1900.]

424 VISIT TO THE GEOLOGICAL SOCIETY'S MUSEUM.

publications, historical collections, and miscellaneous material.
It was especially rich in foreign specimens, which were arianged
geographically. The British specimens were arranged stratigraphi-
cally. The collections had been partially catalogued by Lonsdale,
B. B. Woodward, and others, and completely by the Director
between 1890 — 1898. There had been no proper Curator for
many years, and consequently the collections were in a dirty and
uncared-for condition, but owing to the watchful care of Mr. Wm.
Rupert Jones who had for years kept an eye on the cabinets, the
specimens had not suffered in any other way. It is impossible
for officers, already considerably overworked, to do the necessary
work of such a valuable collection.

The principal collections exhibited and explained to the
visitors were the following : the McEnery types from Kent's
Hole, 1826 ; Agassiz's types of fishes from the Carboniferous
of Ireland ; types of Murchison's *' Silurian System " ; Sacrum
of Megalosaurus ; Dr. Hicks* large Paradoxides \ D'Archiac and
Haime's " Nummulitique de Tlnde " types ; Hislop's Indian
types ; Bain's and Grey's S. African types ; Marcou's types of the
" Geology of North America," lost to sight for thirty years, and in
consequence affording a serious bar to the progress of North
American geology ; types of St. Domingo Tertiaries ; D. Forbes'
specimens from the Bolivian Andes ; T. L. Mitchell's Australian
collection, the first collection received from Australia ; his types
of Australian cave-mammals ; Duncan's types of Australian
Miocene corals; and Sharpe's types of Tertiary and Silurian
fossils. Buckland's Rhinoceros from Lawford, and the Granite
boulder from the Chalk of Haling, Croydon (not Purley as always
erroneously quoted). Other curiosities, such as Wm. Smith's
Map and Table of Strata, Moran's beautiful picture of the hot
springs of the Yellowstone, and the portrait of Mary Anning, were
also referred to.

The President, Mr. Whitaker, in his remarks referred to
the interesting fact that for the first time in the history of
the Association, and of the Society, he held the position of
President of both bodies, at one and the same time, for that
particular month, and that the two bodies had just interchanged
presidents, a fact that was enthusiastically received. The usual
votes of thanks were passed, and the members of the Association
were much pleased at the generosity of the Society in allowing
them to inspect their collection. It was hoped that at an early
date the collection would find a home in some public building,
where they could be available to all students.

425

EXCURSION TO NEWTON ABBOT, CHUDLEIGH,
DARTMOOR, AND TORQUAY,

Easter, 1900.

Directors'. Horace B. Woodward, F.R.S., F.G.S.,
A. R. Hunt, M.A., F.L.S., F.G.S., and W. A. E. Ussher, F.G.S.

Excursion Secretary : PERCY Emary, F.G.S.

{Report 6y The Directors.)

I.— Newton Abbot, Bovey Tracey, and Chudleigh.

By H. B. Woodward.

During the Easter excursion of 1899 the members of the
Association examined for the first time the coast of South
Devon from Seaton to Exmouth, and proceeded from Exeter as
far as Great Haldon.* On the present occasion they investigated
a further portion of South Devon, to which no excursion had
previously been made, except on one occasion, July 23rd, 1884,
when, under the guidance of William Pengelly, and during the
presidency of the late Dr. Hicks, the members proceeded from
Plymouth to Torquay for the day, saw the coast at Hope's Nose,
and visited Kent's Cavern. t

On Thursday evening, April I2ih^ the members of the party
arrived at the Globe Hotel, Newton Abbot

On Friday, April 13th, they started at nine a.m., and were
driven through the old town of Newton Bushel to the hill on
which Knowles Quarry is situated. Here was to be seen an
intrusive mass of ophitic dolerite or diabase (with chlorite), which
had produced a spotted alteration termed "Spilosite," on the
adjacent Upper Devonian slates. Much of the diabase was in a
decomposed state, and the Director remarked that it was a good
instance of the rotten nature of much of Devonshire, a state due
to prolonged weathering, and which added greatly to the
difficulties of geological mapping. The igneous rocks formed
many isolated knolls in the district, and this appeared to be
due not altogether to their hardness, but partly to their porosity
after decay. They rose up like outliers of Bagshot Sand in a
London Clay area. Nevertheless they had their uses, for while
the solid rock at a depth provided road-metal, the deeply-rotted
portion was a water-baring bed, and gave out springs. Among
the fossils noted from the slates by Mr. Ussher were Posidonomya
venusta, Trilobites of the genus Phtuops, and Ostracods. The
beds belonged to the division known as the EntamiS'S\zXt^ (or
Cypridinen-schiefer).

• Proc, Geot, Assoc. f vol. xvij p. 133.
t Proc. Geol. Assoc., voL viii, p. 47a.

Proc. Geou Assoc. Vol. XVI, Part 8, July, 1900.] 32

426 EXCURSION TO NEWTON ABBOT, CHUDLEIGH,

The party was then driven on by Blatchford and Forges
Cross to Sandpit Copse, south of Lower Staplehill. Here, at an
elevation of 223 feet, was a sand-pit showing highly-inclined beds
of sand and gravel, with pipe-clay and traces of coloured clays,
dipping towards the Bovey valley at an angle of about 35 d^.,
and resting against Devonian slates. The gravel yielded fragments
of veined grit, chert, igneous rocks, and more rarely Greensand
chert and Chalk flints. This was one of the sections referred to by
Mr. Clement Reid in his paper on the Eocene deposits of Devon.

Driving on by Blackpool and Halford, the members were now
conducted to the old Lignite Pit by the Bovey Tracey Potteries ;
a pit rendered famous by the researches of the late William
Pengelly and Oswald Heer. The pit was partially filled with
water, but the banks showed fine white sandy clajrs, coloured
clay, and coarse sands, with thin flaky lignite bands.

The lignite had been worked since about the year 17 14, and
was known as the Bovey coal, the thickest bed being about six
feet. When burnt, it gave out much smoke and an unpleasant
odour. Dr. Falconer had first suggested that the lignite-beds
might be of Miocene age, and. through his influence, Pengelly
started his explorations with the aid of Mr, Henry Keeping. The
section was then cut clear, and they were enabled to examine over
100 feet of the strata which dip to the south at 5 deg. The
plant-remains were examined by Dr. Heer, who regarded them as
Miocene, and as akin to those of the Hempstead (Hamstead)
Beds of the Isle of Wight. More recently Mr. J. Starkie Gardner
had shown that the flora was practically identical with that of the
Bagshot Beds of Bournemouth. The lignite was mainly composed
of coniferous wood, and among the species identified, the Sequoia
couttsicB was noteworthy. The oaks, laurels, figs, and cinnamons
of Bovey were identical with those of Bournemouth.* No animal
remains, with the exception of one insect, had been found in the
deposits.

As originally pointed out by De la Beche, the strata had been
deposited in a large lacustrine area, the clays (an impure china-
clay) being due to the decomposition of the felspars, and the
sands being derived from the quartz of the Dartmoor granite, t

Driving across Bovey Heath, the members next visited the
large clay-pit belonging to Messrs. Candy & Co., at the Great
Western Potteries, near Heathfield Station. Here a variable
series of grey and white clays, carbonaceous sands, and occasional
lignite-beds was to be seen. It was mentioned that a boring had
been carried to a depth of 520 feet from the surface through clays,
sands, and lignites without reaching the base.J The beds here

• Gardner^ Geol Mag., dec. ii, vol. vi, p. 1^2 '■> Quftrt. Journ. Ceol. Soc., vol. xxxv
p. 227 : xxxviii, p. 3-

t ** Rej)orl onGeology of Cornwall," etc., pp. 255, 511.

X A boring made more than sixty years ago near Bovey Tracey passed through nearly,
300 feet of Bovey Beds.— De la Beche, op, cit.^ p. 248.

DARTMCX}R, AND TORQUAY. 427

dipped at an angle of about 8 d^. towards the W.S.W. At
this pit, Messrs. Candy & Co. manufactured all kinds of sanitary
ware, white and coloured glazed bricks, fire bricks, etc.

Elsewhere in the Bovey basin the white pipe-clays and the
darker potters' clays were dug and shipped from Teignmouth, not
only to the potteries of North Staffordshire, but to various parts of
Europe. In 1898, nearly 38,000 tons of clay were dug, the total
value being estimated at a little over ^18,000.

Attention was drawn to the fact that the surface-layers of the
Bovey deposit had here and there been rearranged and redeposited
in Pleistocene times, as proved by the discovery, made in 1872
by Dr. Nathorst, of Betula nana, the dwarf arctic birch. These
remains had been found in the surface deposits in a pit between
the Bovey Tracey potteries and those of Heathfield. It was also
stated that remains of a canoe had, in 1881, been found in the
Heathfield pit, and attention had been drawn to the discovery by
Pengelly, who thought that the object was of Glacial age.* There
was, however, no reason to assign so great an antiquity to the canoe,
for, although the surface was a little over 90 feet above sea-level, and
perhaps 40 feet above the level of the adjacent Bovey river, in
ancient times there were doubtless pools and boggy places in the
broad Bovey valley in which a canoe might have become mired.
Indeed, J. G. Croker had remarked in 1856 that, until within the
previous ninety years, when it had been drained, the Bovey basin
had been almost a swamp. t Moreover, during February, in the
present year, exceptionally heavy floods had occurred in the valley,
so that the road between Kingsteignton and Newton Abbot
became impassable, owing to a heavy snowfall and subsequent
thaw, accompanied by heavy and continuous rain. In the old
alluvial gravel of the Teign, at the Zitherixon pit, which lies a little
west of the road just mentioned, there were discovered, many
years ago, a wooden doll (possibly an emblem of phallic worship)
and also a bronze spear-head, objects which were kindly exhibited
at the Globe Hotel, by Mr. C. D. Blake, of Newton Abbot.

Crossing the river Bovey and the Teign at New Bridge the
party was now driven to a newly opened lignite-pit in the " Great
Plantation," east of Preston Manor clay works, and a little to the
east of the high road between Chudleigh and Newton Abl^ot.
Here an excellent section of the lignite- series with bands of potters*
clay had been opened up in proximity to other pits where pipe and
potters' clay were extensively dug for Messrs. Watts, Blake, Bearne
& Co. The lignite was used for fuel in the stationary engine
which worked the machinery employed in the pits. There was
no time for a detailed study of these lignite beds, but the illustration
(Plate XII, Fig. 2), from a photograph taken by Mr. A. K. Coomara
Swamy, well shows the alternation of potters' clay and lignite.

• Ttatu. Devon Astoc . vol. xv, pp. 376, :95.
t Quart. Jaunt. Geol Soc., vol. zii, p. 3^.

428 EXCURSION TO NEWTON ABBOT, CHUDLEIGH,

Mr. Bauerman remarked that the lignite was somewhat similar
to the Brown Coal of Tertiary age, worked in various localities on
the Continent.

Returning by the high road the members were now driven by
Bellamarsh Barton, where, alongside the river Teign, sections of
disturbed Culm-measures were to be seen. Alighting near
Chudleigh Station, the members were met by Mr. W. A. E. Ussher,
who now took up the duties of Director, and also by CoL
Walcott, of Rock House. Walking by Lawell House and across
Kate Brook, a small section of cherty beds in the Lower Culm-
measures was examined. This showed about 12 feet of dark
chert beds of the Basement Culm-measures, in which Messrs. Fox
and Hinde had found Radiolaria.* Mr. Ussher pointed out the
structure of the Chudleigh valley, where the Devonian slates
and limestones occur bounded on all sides by faults, bringing them
against different portions of the Culm-measures. In the Chudleigh
gorge he remarked that the relations of the Devonian slates and
limestones were apparently due to the exposure of slates by denu-
dation of the overlying limestones; this however, he considered
illusory as the slates seemed to be of later formation than the
limestones, and the latter, if not overthrust upon them, would
appear to have been formed by coralline growths in clear water at
a more rapid rate than the muddy sedimentation which was after-
wards slowly accumulated on their margin, so that beds of slate
of Upper Devonian age might be banked against limestone of the
massive type either of the zone of Rhynchoneila cuboides or of indis-
putably Middle Devonian age. This explanation, he said, had
been put forward by him ten years ago, to account for phenomena
such as the relations of the slates and limestones of Chudleigh
gorge, and the outer edge of the Newton Abbot limestones near
Chircombe Bridge at their junction with slates.f The Chircombe
Bridge limestone was considerably lower in the series than the
Chudleigh limestones, and again the Ashburton limestone was
separated from the Newton Abbot limestones by slates in part
corresponding to the Cypridinen-schiefer, and containing the
characteristic Ostracoda of that Upper Devonian group. Hence
the connection of the Ashburton and Newton limestones not only
demanded a synclinal structure, but also considerable difference
in rates of organic growth and muddy sedimentation, unless the
limestones were bounded by faults, of which there was not
sufficient evidence.

Having proceeded a short way up Chudleigh Glen, the fine
crags of Devonian Limestone and the entrance to one of the
Chudleigh caves were seen. Col. Walcott then led the party-
through his picturesque grounds, in which an old quarry and
another cavern are situated ; then a halt was made at Glen

♦ See Tram. Devon Assoc, vol. xxix, 1897, p. 518.
t Qttaft.Joum, Ceol, Soc., vol. xlvi, p. 513.

DARTMOOR, AND TORQUAY. 429

Cottage, adjacent to the Palace quarry, and a little above the
Chudleigh waterfall. In this quarry fine examples of Murchisonia
have been obtained.

Mr. Woodward exhibited specimens of Rhynchonella cuboides
and Heliolites porosus^ examples of which had been obtained
from the Chudleigh quarry.

Mr. Ussher remarked that the occurrence of the Frasnian
(lower part of Upper Devonian) shell in the same quarry with
the Middle Devonian coral, was parallelled in other well-known
quarries, such as those of Wolborough and Lummaton. It
appeared that the massive limestones of the Torquay, Chudleigh,
and Newton district, which in the Lower Dunscombe quarry and
at Petitor were immediately overlain by shaly, irregular, liver-
coloured limestones, containing Upper Devonian Goniatites, such
as G. intumescens and G. Sagittarius^ represented the basement
Upper Devonian beds of the Continent, viz., the massive lime-
stones of the zone of Rhynchonella cuboides^ but in Devon there
was a blending of Middle and Upper Devonian forms in them.
If there were not a blending the fact of the discovery of fossils
characterising different horizons in the same quarry must be
ascribed to plications which in the massive limestones cannot
be traced, but are nevertheless scarcely ever absent from the
Devonshire Devonian rocks.

Driving then through the town of Chudleigh, and down the
narrow street by the Town Mills to Biddlecombe Cross, the
members again alighted, and walked eastwards to the lane leading
downhill towards Waddon Barton. Here they examined the
lower beds of Culm-measures, rendered classic by the labours
of the late J. E. Lee and Dr. Henry Woodward. The section
was somewhat overgrown, but the party succeeded in bringing to
light many specimens of the characteristic even-bedded reddish
brown stone, which being split along the direction of the bedding
surfaces, revealed traces of the characteristic Goniatite, G, spiralis^
pK)riions of Phillipsia, and traces of Posidonomya, Mr. Ussher
showed the position of the beds in faulted contact with the
prolongation of the Chudleigh limestone on the north and south,
the limestone on the south side passing under green Upper
Devonian slates at Waddon Barton.

The time spent in exploiting the lane unfortunately necessitated
the abandonment of the visit to the Ix)wer Dunscombe quarry
which, situated between converging faults, is very near Waddon
Barton lane. There the " Goniatite-Beds," red shales and
limestones with Goniatites intumescens^ overlie limestone with
Rhynchonella cuboides y etc.*

Rejoining the carriages, the party was now driven through the
picturesque grounds of Ugbrooke Park, by kind permission of

• Quart. /ffum, GeoL Sac., voL xlvi, pp. 507, 511

430 EXCURSION TO NEWTON ABBOT, CHUDLEIGH

Baron Clifford of Chudleigh. The conglomeratic sandstones of
the Culm-measures were noticed by some of the members.

Passing Babcombe, a halt was made at Fosterville, and most ot
the members, under the guidance of Mr. Woodward, walked by a
pleasant lane and then across country, through woodland, moor,
and marsh, to the Lappathom Clay pits, and on to Abbrook.
Here evidence was seen of the interbedding of gravel with the
white clays of the Bovey Beds, the whole overlain by a head
of coarse ferruginous gravel which became thicker towards
Abbrook, and appeared to be rearranged gravel, not, however, far
removed from its parent source. From Abbrook, the party was
driven through Kingsteignton to Newton Abbot.

II. — LUSTLEIGH AND DaRTMOOR.
By A. R. Hunt.

On Saturday^ April 14th, the members took the 9.43 a.m.
train from Newton Abbot to Lustleigh. [At Newton Abbot they
were joined by Mr. and Mrs. A. R. Hunt, Bishop Mitchinson,
the Rev. G. F. Whidbome, and Mr. A. Somervail.] Leaving
Lustleigh Station, they proceeded by Rudge and Hisley to the
weir near the junction of Becka Brook and the River Bovey. A
halt was called at Rudge, to point out the railway-cutting in which
the Culm rocks come into abrupt contact with the fine schorlaceous
granite commonly known as elvan. In Hisley Wood, the party
passed from the ordinary Dartmoor granite over an obscured
junction to the Culm. A quarter of a mile beyond the weir, the
Becka Brook was crossed by a footbridge near the point of
Houndtor Ridge, a remarkable arete of Culm grit dividing the
valleys of the Bovey and the Becka. The ascent of the Ridge,
some 500 feet, along a steep and narrow pathway, afforded
beautiful views on either side. It was pointed out that both the
quartz-veins and elvan-veins in the Culm shared with the main
granite and elvan the characteristic of containing fluid inclusions
with chlorides. At the summit of the Ridge (Water Rock on the
old i-inch map, nearly 800 feet above sea-level) the Culm rock is
intersected by numerous elvan veins which were carefully
examined.

Leaving Water Rock, the party proceeded by Becka falls, and
the Rev. Preb. Wolfe's private drive (by kind permission), to
Houndtor, noticing on the way a remarkable contact of fine and
coarse granite in a roadside block, and some torrential rubble
drift between Leighon and Houndtor farm. Arrived at Houndtor,
luncheon baskets and sandwiches were in immediate request, after
which the party climbed to the top of the tor, which is about
1,200 feet above sea-level. Several Dartmoor questions were
forthwith discussed.

DARTMOOR, AND TORQUAY. 431

The Director made some observations on the origin of tors,
and

Mr. Teall (President of the Geological Society) discoursed on
the petrological characters of the Dartmoor granite.

Mr. Woodward remarked that not far off, near Hay Tor (or
Heytor), there had been an iron mine where magnetite occurred
interstratified with the altered shales and sandstones of the Culm-
measures. According to Prof. Le Neve Foster, the iron-ore,
originally brown haematite, had been altered by the granite, as
also had the associated strata. The altered rocks contained
hornblende and actinolite, garnets, pyrites, etc., also a mineral
named Haytorite, which was chalcedony pseudomorphous after
datholite.* i

Mr. Somervail drew attention to the fact that in the great
expanse of Dartmoor, where there were no distinct evidences of
glacial action, there were no tarns, whereas such sheets of water
were common in the glaciated regions of Scotland.!

Mr. \V. P. D. Stebbing referred to the discovery of blocks of
granite in the Chalk of the south-east of England. It had been
suggested that some of these boulders had come from Dartmoor,
but Prof. Bonney considered this place of origin most improbable.

The members now proceeded across the moor to a granite
pinnacle known as Bowerman's Nose, and the opportunity wa.
taken to photograph the rocks. The accompanying view (PL XII,
Fig. i) is from a photograph by Mr. H. Preston. Thence the
route led through Wingstone and Manaton (Half Moon) to
Foxworthy [the country cottage belonging to Mr. and Mrs. Hunt,
where an excellent tea had been most kindly provided].

The Director, with the vanguard of the party, pressed on to
examine some large mounds of rounded rubble in Peck Pits, and
also a Hut circle. The field which contains this Hut circle is
called the Maryhay — a curious survival of Saxon times, viz., the
" merihay " or boundary hedge. It still is the boundary hedge,
and the only non-natural boundary of the little farm on the east
side of the river.

Many Hut circles have been observed on Dartmoor, and they
are regarded as foundations of early habitations. Some of them
had stone walls four or five feet high, which were used probably
to support wooden poles and a roof of rushes. Flint flakes,
scrapers, and cooking-stones have been found in the Hut circles,
but no metal implements and no pottery.

A hearty vote of thanks having been accorded to Mrs. Hunt,
the return journey was made by Raven's Tor and Lustleigh
Cleave to Sharpitor, the Nut Crackers (a logan stone), and
Lustleigh Station.

On the way the party first inspected a felspar-quartz-schorl

• Quart. Joum. Geol. Soc-, vol. xxxi, p. 6a 3.
t Trans. Devon Assoc.^ vol. xxix, p. 386.

432 EXCURSION TO NEWTON ABBOT, CHUDLEIGH,

vein in sitH^ the minerals being those of the elvans, but the
structure not granitic.

Then two small but deep rock-basins attracted attention.
Similar to pot holes in streams, these basins were clearly formed
by the solvent action of rainwater, probably acidulated by the
decay of lichens and other vegetation.

Lastly, a split block of granite attracted much attention, pre-
senting as it did an exceptional number of Dartmoor problems,
such as concretions of two sorts, latent planes of weakness, dis-
solution of orthoclase crystals, twin crystals of orthoclase, and
rearrangement of minerals.

III.— Watcombe.

Bv H, B. Woodward.

On April ijth the members proceeded by train from Newton
Abbot to Kingskerswell, whence the road was taken by Kings-
kerswell Cross and Barton Cross to the Mincent Hill quarries at
Barton. Here the Devonian Limestone was well exposed, and
yielded numerous corals. From this locality and the adjoining
quarries at Lummaton, the Rev. G. F. Whidborne had obtained
many fossils, figured and described in his Monograph, published
by the Palaeontographical Society. While the mass of the Lime-
stone is Middle Devonian, part of it is regarded as probably Upper
Devonian by Mr. Ussher. An interesting coral-breccia was noted
by him.

After passing near the Watcombe Terra Cotta Works, the
members took lunch at the " Palk Arms," and then proceeded by
Easterfield Lane to the grand cliffs of New Red sandstone and
conglomerate at Watcombe. A fine view was obtained of the red
cliffs looking northwards towards Teignmouth and Exmouth.
The Director called attention to the Teignmouth pebbles, which,
as sold to the public, were polished pebbles of fossiliferous
Devonian Limestone obtained from the conglomerate on the
beach. The curious coating of annulated chalcedony, named
beekite after Dr. Beeke, a former Dean of Bristol, was obtained
on the coast.

The lowest division of the New Red Series, the Watcombe
Clay, was faulted on the south against the Red Conglomerate.

Passing round to Watcombe Head, and along the northern
margin of the Valley of Rocks, the path became for a time
obscure ; but after scrambling through a fence, and traversing
some private grounds, the members reached the high road near
Maidencombe House. Thence the way led through Higher
Rocombe to Haccombe Cross (524 feet), whence a fine view of
Dartmoor was obtained. After walking through the picturesque
village of Coffinswell, the large gravel pit in Harpin*s Brake, near
Aller Farm, was visited ; and farther on, past the Aller Vale

DARTMOOR, AND TORQUAY. 433

Potteries,* another gravel pit was seen. In both places there was
much coarse flint gravel inclined towards the valley, and includ-
ing in places layers of white clay, and coloured sands, which
tended to correlate them with the Bovey Beds.

The members returned to Newton Abbot by Ford House.

IV.— Babbacombe and Kent's Cavern, Torquay.

By W. a. E. Ussher and A. R. Hunt.

April i6th, — ^The members took train to Torre Station, and
were thence driven to Petitor. On arrival at Petitor rock (300
feet above sea-level) Mr. Ussher pointed out the features of the
valley. The limestone knoll of Petitor was examined, and found
to consist of closely matted corals. From the knoll the limestone
was shown to attenuate in a narrow ridge seaward, terminating on
the beach in a pinnacle of shattered limestone penetrated by
infiltrated materials from the overlying New Red rocks. These
New Red rocks, consisting of clays with sandy bands (really com-
posed of triturated Devonian slates), and brecciated at the base,
were seen resting directly on the limestone and faulted on the
north against the breccio- conglomerates with large limestone
fragments, which forms the fine, commanding crags bounding
Petitor Combe on the north. Mr. Ussher pointed out the rela-
tions of the Watcombe clays to these breccio-conglomerates.
The upper part of the Watcombe clays pass under the con-
glomerates which form the crags of Watcombe Combe, the lower
beds of the clay series exposed in Petitor Combe being separated
from them by an intervening mass of the conglomerate faulted
down on both sides. The breccio-conglomerates pass conform-
ably under the rubbly breccias with quartz porphyry boulders seen
last Easter between Exeter and Haldon.

Turning to the Devonian rocks, Mr. Ussher showed that the
lower part of the Petitor valley consisted of red Upper Devonian
slates bounded by limestones on both sides. He said that the
apparently horizontal character of the limestone on the south side
had always been taken as evidence of an anticlinal structure broken
by denudation and exposing underlying slates. From a close
study of the characters of the Upper Devonian slates of the area,
he had been led to doubt the truth of this anticlinal structure,
which was figured by De la Beche, and after careful investigation
he had discovered traces of the liver-coloured shaly limestones of
Lower Dunscombe at the junction of the slates and limestones on
either side, and was also fortunate enough to obtain Goniatites,
including G. Sagittarius^ in them. He showed that the apparent
horizontality of the limestone between Petitor Combe and Oddi-
combe beach was due to close zig-zag (corkscrew-like) contortions
in the vertical limb of the syncline on that side, whilst the
shattered character of the limestone ridge on the opposite side

* The clay here used \s mostly obtaioed from the Bovey Beds at Kingsteignton.

434

EXCURSION TO NEWTON ABBOT, CHUDLEIGH,

t^«"

any recent
acquiesced

of the syncline rendered the detection
of bedding planes impossible. In both
limestones the structures (fibro-crystalline
calcite veins) called " stromatactis " by
Dupont were shown to occur ; and in the
intervening slates Posidonomya venusta^ a
characteristic local Upper Devonian fossil,
was obtained. On reaching Oddicombe
sands the party were shown a faulted
junction between Devonian limestone
and New Red breccio-conglomerates.
In the breccio-conglomerates local beds
of sand were pointed out, the junction
of the materials affording pretty exam-
ples of contemporaneous erosion.

Mr, Hunt pointed out that after
easterly gales Oddicombe beach often
affords a good example of the general
rule that large beach-shingle will travel in
the direction of the wave-stroke along
the beach, whereas sand and small shingle,
remaining in the grasp of the wave, will
travel with the current, which as likely as
not is in the reverse direction. Although
the Oddicombe limestone-shingle is at
the foot of the New Red limestone con-
glomerates, the cliflfs have not supplied
the shingle ; which is really derived from
the dkbris tipped into the sea at the
great Devonian Limestone quarry near
Anstey's Cove.*

Mr. Hunt, turning to the cliffs,
remarked that the conglomerates were
too angular and irregular for marine
action, and on too vast a scale for river
action. He knew of no agency to which
1:1:51 they could be attributed. Mr. Teall at
•^;jS once pointed out that similar accumula-
ro w h4 tions were known in the Himalayas,
where the disintegration of strata ex-
ceeded the available transport ; the
conglomerates were torrential Mr. Hunt
observed that he had not ventured to
use the word torrential for phenomena
on so grand a scale, being unaware of
examples, but that he gratefully accepted, and fully
in Mr. Teall's explanation.

• See Trarts. Roy. Dublin Soc, vol. iv, 1885, p. 283.

CO rtTJ.S

DARTMOOR, AXD TORQUAY. 435

Mr. Ussher, in resuming, showed that the dips in the breccio-
conglomerates, in places amounting to over 40 d^., were due to
faults. He considered that the series was the same as that of
Watcombe and Petitor crags let down on either side by faults.
On the south side the New Red was shown in faulted contact
with dark slates visible in and at the base of the tumbled under-
cliff materials, as far as the Cary Arms. The party ascending the
cliff by the path was shown the well-bedded limestones (Middle
Devonian) of Babbacombe with a bolster-like mass of igneous
rock, probably in part decomposed schalstein exposed on
the axis of a uniclinal curve. In this connection Mr. Ussher
pointed out the structure as a nearly vertical contact of limestones
with contemporaneous igneous rock zigzagged by numerous folds,
and dark slates with masses of ophitic dolerite (diabase) probably
intrusive in them in several places. These bedded limestones
and dark slates, he said, were lower in the series than the Petitor
limestones on the north and the massive limestones of the Cary
Arms coast against which they are faulted on the south ; a patch
of decomposed and broken red igneous rock at the little boat pier
at the Cary Arms being in the vicinity of the fault.

After much needed refreshment at the Cary Arms, the party
ascended the hill to the level of Babbacombe Downs, under the
guidance of Mr. Hunt, and observed a shallow valley about 400
feet across, draining landwards, it having been truncated by the
erosion of the great West Bay. This valley passes at the foot
of the Kent's cavern hill and debouches into Torbay. It com-
pletely isolates the limestone plateau between Babbacombe and
Anstey's Cove. This plateau is the highest of a series described
by Pengelly as terraces of denudation, which further occur in
descending order, at Daddy Hole Plain, Waldon Hill, and Berry
Head, in which neighbourhood Permian dykes are levelled with
the limestone, indicating that the era of denudation is post-
Permian. In the Walls Hill quarry, through which the valley
passes, the Association examined the process of the formation of
caves by the enlargement of joint planes, and the origin of cavern
accumulations by the infilling of clay, with occasional foreign
pebbles, from the surface of the plateau ; the arrival of the pebbles
on the isolated plateau apparently antedating the erosion of the
shallow truncated valley. The limestone was seen to be traversed by
joint planes intersecting roughly in the direction north and south,
and east and west, perhaps more nearly north-east and south-west.

At Anstey's Cove the party was divided, and Mr. Hunt
conducted the first division to Kent's Cavern. While the candles
were being prepared, he mentioned some of the surprising
theories of cavern critics, ^.^., that the extinct cave-mammalia
were introduced by the Romans to work in the mines ! '' On
entering the cave the visitors assembled in the Great Chamber.

• S«« Trmns. Devon Atsoc., vol. xv, p. 485.

436 EXCURSION TO NEWTON ABBOT, CHUDLEIGH,

Large as it is, it must on no account be taken as represen-
tative of the cavern as a whole ; as in it the two most interest-
ing and ancient deposits — the crystalline stalagmite and its
subjacent breccia — did not occur at all; nor was their exist-
ence suspected until after the Great Chamber had been ex-
plored. Passing through this chamber the party entered in
single file the "Gallery," to inspect an interesting basin with
corrugated sides and divisions formed by the ripples created by
falling drops of water. This is the very latest stalagmite in the
cave, as it was in process of formation when the explorers found
it The ** Gallery " is crossed by a ceiling of the old stalagmite
and its history is as follows : First nearly filled with " breccia,"
this deposit was covered by an old stalagmite floor. The breccia
was cleared out and " cave-earth " introduced. The cave-earth in
turn was covered by the newer stalagmite, under the older. This
little chamber nonplussed the early explorers, who were naturally
entirely ignorant of the existence of the ancient stalagmite and
breccia. Leaving the " Galleiy," the party passed in single file
into the " Water Gallery," under the ancient stalagmite floor, in
which bones of bear aie embedded. At this spot there occurred
the first " palaeolith " flint-fragments which so astounded the
explorers.* After a glance at the vestibule, the site of the '* black
band," and its bone tools, the party proceeded to the Wolf's Den,
where MacEnery found Macharodus latidens\ a find greatly
discredited until the British Association Committee found another
tooth of this sabre-toothed tiger in the Long Arcade further on in
the Cavern; a find of more value as reinstating the credit of
MacEnery than for the interest attaching to the great carnivore
itself. The party then examined the Bear's Den ; a chamber
which greatly puzzled MacEnery, ignorant of the fact that he was
dealing with a far more ancient stalagmite than he had investigated
in other parts of the cave. From the Bear's Den the visitors
proceeded to the Rocky Chamber, noticing the famous " Hedges'
Boss " on the way. The Rocky Chamber, investigated late in the
explorations, has scarcely received the attention it deserves, as
the pipe-like stalagmites springmg from larger bosses seem to
indicate a considerable variation in the rate of accumulation of
carbonate of lime at some unknown period of the cavern's history.
In considering the question of the Kent's Cavern stalagmites, it is
well to bear in mind that the atmosphere being saturated, there is
no evaporation ; that the formation of stalagmite there is a question
of a little more or less carbonic acid in the water, and a difference
of a few degrees of temperature in the cave. Whether the
incoming water will corrode the limestone, or deposit carbonate
of lime, apparently depends on whether the lime-charged water
enters an atmosphere cooler or warmer than itself. In tie former
case it may dissolve, in the latter deposit.

• Sec Trans. Dei>on Assoc. y vol. v, p. 26^.

DARTMOOR, AND TORQUAY.

437

••**^

Rough Sketch Plan of Kent's Cavern (/(. R, HunC).

A. Great Chamber.

B. Gallery.

C. Lecture Hall.

D. S.W. Chamber.

E. Water Gallery.

F. Passage of ifms.

G. Vestibule.

H. Sloping Chamber.
I. Wolfs Den.

J. Charcoal Cave.
K. Long Arcade.
L. Underhay's Gallery.
M. Clinnick's Gallery.
N. Rocky Chamber.
O. Cave of Inscriptions.
P. Hedges' Boss.

H. Swallow Gallery.
. Great Oven

S. Lab3rrinth.

T. Bear's Den.

U. Tortuous Gallery.

V. Lake&Cryptof Dates

W. North Sally Port.

X. Underground

Passage.
Y. Smerdon^ Passage.
Z. Inscribed Boss.

Although the plan of Kent's Cavern makes no claim to accuracy, it may be
as well to mention that there is a slip in the passage to Q fthe Swallow
Gallery), the passage actually surting as a continuation of R (the Great Oven),
instead of as a continuation of O (the Cave of Inscriptions).

438 EXCURSION TO NEWTON ABBOT, CHUDLEIGH,

The most impressive facts in the cavern are the rocky
crystalline stalagmite and the spongy porous stalagmite. They
seem to tell of slow climatic changes of incalculable duration.
The eroded valleys tell a like story. The advent and disappear-
ance of the hyaena, as a short episode in the cave history may give
us pause ; but the stalagmites cannot be regarded as indices of
time-gaps. We need not expect either man or beast to inhabit by
choice the wettest portions of the cavern, or to find many bones
in stalagmite ; but as a matter of fact bones of bears were found
throughout the ancient floor, and hyaena, rhinoceros, and others
in the newer floor, close up to the surface.

Nearly eighty implements and fragments were found in the
breccia.* Pengelly calls them " nodule " tools, as distinguished
from the cave-earth palaeolithic tools, which are trimmed flakes,
whereas the breccia tools are trimmed nodules. The fact is, that
in Kent's Cavern we have two epochs of palseoliths, with an
amount of time supposed to be represented by 12 feet of
stalagmite + x years between them. There is no proof that
the breccia type of tool was ever made in the cave-earth era.
Of course a " cave-earth " man might find a ** breccia " tool, just
as we ourselves might at the present time.

Before the first party had seen the cavern, the second party
was ready to enter, but unfortunately time was running very short,
and their inspection was somewhat hurried.

In Anstey's Cove Mr. Ussher showed that the red and green
slates as at Petitor were newer than the limestones which they
seemed to underlie, and at the junction with ihem exhibited evidence
of the presence of the liver-coloured Goniatite beds. On Red-
gate beach the eyes of the party were gladdened by a com-
paratively simple series of curves, bringing the beds at the base
of the fine cliff" to its crest in convolutions of different degrees
of intensity; but this glimmer of simple fact was soon clouded
over when it was pointed out to them that limestones of different
horizons in the mass were brought together by faults at either end
of the beach along the projecting cliff" faces, and by faults parallel
to the main cliff*, crossed and shifted. There was hardly time to
deal with more than five or six of these, when it was found
advisable to proceed to the cavern from which the first party soon
emerged.

The Rev. G. F. Whidborne led a small party to Hope's
Nose, where they had the opportunity of glancing at the Raised
Beach.

The members now proceeded to the Torquay Museum, and
examined the fine collection of local fossils. After which they
were entertained to tea by the Committee of the Torquay Natural
History Society. Before parting, Mr. Whitaker, the President of
the Association, proposed a hearty vote of thanks to the Torquay

• See Trans. Dct'on Assoc., vol. xiv, p. 685.

DARTMOOR, AND TORQUAY. 439

Natural History Society for their hospitality, which was greatly
appreciated, and he also returned thanks to Mr. Hunt and Mr.
Ussher for their services as Directors on this and other occasions.
Mr. Boase, President of the Torquay Natural History Society,
and Mr. Hunt briefly replied.

In contrast to the proceedings under the guidance of Mr. Hunt, Mr.
Woodward (in seconding the vote of thanks) referred to the visit paid to
" Kent's Hole/' in 1794^ by Mr. W. G. Maton, F.L.S., who thus wrote :
*' Two women, whose usual business it is, conducted us to the spot, provided
with candles, tinder-boxes, and other necessaries for the expedition. After
pursuing rather an intricate track, we arrived at the mouth of the cavern. . . .
The aperture was just large enough to admit us. . . . We began to fancy
ourselves in the abode of some magician, or (as our companions were two
ancient females, and not the most comely of their years) in the clutches of
some mischievous old witches. . . . The roof is in some places so low we were
obliged to advance on our knees."*

v.— Nk\vton Abbot, East Ogwell, and Wolborough.

By H. B. Woodward.

On Tuesday^ April 17th, the members started by Mill Lane
and past the Bradley Manor House on the borders of the River
Lemon, where in the bed of the stream the Director had found a
polished stone-implement. After a pleasant walk along the
wooded ravine the quarries on the north side of the valley in
Broadridge Wood, and near Chircombe Bridge, where the Middle
Devonian Limestones are well exposed, were visited. Crossing
the bridge, and taking the path on the south side of the stream,
an old limestone quarry was next visited, and then the scarp was
ascended to the Pulpit Rock. Here the Limestone yields in
abundance the Coral, Favosites {Pachypora) polymorpha. Occu-
pying the pulpit the Director made some general remarks on the
Devonian series, on the pioneering work of God win- Austen, and
on the difficulties met with in Devonshire. Lonsdale's original
observations (dating back to 1837) on the Devonian system were
referred to, and it was pointed out that his suggestion of a
formation intermediate between the Silurian and Carboniferous
was based on a study of the fossils of the South Devon limestones.
Neither the top nor the base of the Devonian system was then
defined.

Reference was made to the subsequent work of Holl, and
more especially to that of Champernowne, Mr. Ussher, and the
Rev. G. F. Whidborne.

The difficulties in determining the secjuence of the local
Devonian rocks were very great, owing to the irregularities of the
strata, and the great disturbances to which they had been
subjected. The fossils, too, were more often than not crushed and
badly preserved. Light, however, had been obtained by studying the

* " Observations relative chiefly to the Natural Hutory, etc., of the We«tem Counties of
England," 1797, p. 119.

440

EXCURSION TO NEWTON ABBOT, CHUDLEIGH,

divisions made in Germany, and by applyipg the zonal succession
there established to the elucidation of the Devonian sequence in
this country. Different stratigraphical divisions roust, however,
be made in this country, as abroad, where the Franco-Belgian
grouping differed from that in Germany.

As Mr. Ussher had pointed out, the Middle and Upper
Devonian Beds were to some extent locally represented by a
mass of limestones in which no definite plane of division could
be made. Thus we had the lower portions of the limestone-
series at Chircombe Bridge, and an ascending series as we passed
eastwards through Bradley Woods to Ramsleigh.

'^■'.-Af ...

Section at Wolborough Church, Newton Abbot.
(^H. B. Woodward, 1896.)

{8. Gravel and sand. 4. Sand and fine gravel.

7. Reddish sand. 3. Sand.

6. Gravel and sand. 2, Clay.

5. Reddish sand. i. Coarse gravel.

Height of section about 30 feet. Length, 60 yards.

Returning along the top of West Hill the members now took
the lane to East Ogwell, crossing the decomposed schalsteins and
limestone, and also slates, on the way to Ramsleigh or Ransley
quarry on East Hill. Here the limestone, as observed by
ChampcMiowne, represented the Frasnian stage of the Upper
Devonian, and was characterised by Rhynchonella cuboides and
Acervularia pentagona. Many examples of the " stromatactis,"
previously referred to, were noticed in this quarry. Eastwards
the limestone is brought abruptly against Culm-measures, which
were seen in the road-cutting. Thence the party proceeded by

DARTMOOR, AXD TORQUAY, 44 1

Ogwell Cross to the quany near Prospect Cottages, Wolborough,
where the Middle Devonian Limestone is much stained with
ferruginous matter derived from the New Red beds.

Phacops latifrons^ BromtcMS flah<Uifer^ Gimiatites^ Orfkpftras^
Stringocepkalus burtini^ Spiriftra verHeMi/i\ Rkyfukeneiia pttgrntts^
and Atrypa reticularis have been recorded from Wolborough,

The gravel pit by Wolborough Church (175 feet above sea-
level) next attracted attention. Here the beds dip towards the
S.E. at from 35' to 45'. The presence of coloured sands and
white clays and the high inclination tended to associate the beds
with those seen at Staple Hill and AUer Vale, and to support Mr.
Clement Reid s contention that all were Bovey Beds.

The Director remarked that during his stay in Newton Abbot,
1874-75, he was sorely perplexed with these and other sands and
gravels. Eventually he came to the conclusion that they w^re
drifts, and that there was some connection between the plateau-
gravels of Haldon and those which occurred with this high
marginal dip in the Bovey Basin.* Now Mr. Reid had thrown
light on the subject. He had traced the extension of the Bagshot
Beds on to Haldon, into the very plateau gnivels.t

On the other hand it is right to mention that Mr. A. E. Salter
has regarded the deposits on Wolborough Hill and Milber Down
as "Lower I^vel Plateau Gravels," derived in part from the
Haldons.J

The members now proceeded by the Newton College recreation
ground to the Decoy Clay pits belonging to the Devon and
Courtenay Brick, Tile, and Clay Co. Here, as pointed out long
ago by J. H. Key, the beds have a considerable inclination
towards the east, and both clays and thin lignites have been
exposed. The clays have been worked to a depth of 90 feet in
some parts, the workings extending along the strike of the highly
inclined beds. Intercalated in the mass of pipe-clays are
occasional layers of sand. The clay is mostly white or pale grey,
but it has pink staining in places, like the coloured clays of the
Bagshot Beds in Dorsetshire.

The members now returned to the Globe Hotel, and the
Easter excursion of 1900 came to an end.

REFERENCES.

Geological Survey Map, New Series, Sheet 339, Newton Abbot, Chudleigh,
and Bovey Tracey ; Sheet 350, Torquay. Old SERIES, Sheets 2J
and 25.

1880. Champernowne, a.—" Upper Devonian in Devonshire." doL
Mag.^ Dec. ii, vol. vii, p. 359.

• Quart.Journ. Geol. Soc., vol. xxxii, p. 234.

t lAid., vol. liv, p. 235.

X Proc Gtol. Assoc., vol. xv, p. a8a.

Proc. Geol. Assoc., Vol. XVI, Part 8, July, 1900. 33

442 EXCURSION TO NEWTON ABBOT, CHUDLEIGH, ETC.

1868. HOLL, Dr. H. B.— "On the Older Rocks of South Devon and

East Cornwall." Quart. Journ, Geoi, Soc.y vol. xxiv, p. 400.

1894. Hunt, A. R.— "Four Theories of the Age and Origin of the
Dartmoor Granites." — Geol. Maff.^ Dec. iv, vol. i, p. 97.

1897. .—♦' West Country Geological Problems. Part II. The

Dartmoor Granite." Trans, Detton Assoc. y vol. xxix, p. 390.

1899. . — " Notes on certain Granitoid Fragments from the Culm

Conglomerates, and Tourmalinized Grits from the New Red Con-
glomerates of South Devon." Geol. Mag.y Dec. iv, vol. vi, p. 256.

1862. Key, J. H.— "On the Bovey Deposit." Quart. Joum, Geol, Soc.,

vol. xviii, p. 9.
1893. McMahon, Lieut.-Gen. C. A. — "Notes on Dartmoor." Quart,
yourn. Geol. Soc.^ vol. xlix, p. 385.

1863. Pengelly, W., and the Rev. Oswald Heer. — "On the Lignite

Formation of Bovey Tracey, Devonshire." PAil. Trans, for 1862 ;

reprinted with prefatory remarks, 4to. London, 1863.
.—(Various mpers and reports on Kent's Cavern.) See

Index of vol. xvi of the Trans. Devon Assoc.
1877. Reid, C. — "On the Junction of the Limestone and Culm-measures

at Chudleigh." Geol. Mag.^ Dec. ii, vol. iv, pp. 454, 455. See also

vol. vii (1880), p. 286.
1898. . — "The Eocene Deposits of Devon." Quart. Joum. Geo*.

Soc.y vol. liv, p. 234.
1880. Roemer, Dr. F. — "Notice of the Occurrence of Upper Devonian

Goniatite Limestone in Devonshire." Geol. Mag.^ Dec. ii, vol. vii,

pp. 145-147.
1898. Salter, A. E. — "Pebbly and other Gravels in Southern England."

Proc. Geol. Assoc. ^ vol. xv, pp. 280-284.
1877, Ussher, VV. a. E.— "The Age of the Watcombe Clay." Trans.

Devon Assoc. ^ vol. ix, p. 296.
1890. . — " The Devonian Rocks of South Devon." Quart,

Joum. Geol. Soc,^ vol. xlvi, p. 487.
1892. . — "The British Culm Measures." Proc. Somerset

Arch. Soc.y vol. xxxviii, p. ill.
Whidborne, Rev. G. F. — " A Monograph of the Devonian Fauna

of the South of England." Palceontograph. Soc. (In progress.)

1869. Whitaker, W.— "On the Succession of Beds in the ' New Red' on

the South Coast of Devon." Quart. Journ. Geol. Soc,^ vol. xxv,
p. 152.
1884. WOODWARD, Dr. Henry.— "On the Discovery of Trilobites in the
Culm-Shales of South-East Devonshire." Geol. Mag.^ Dec. iii, vol. i,

pp. 534-54S.

1876. Woodward, H. B. — "Notes on the Gravels, Sands, and other
Superficial Deposits in the Neighbourhood of Newton Abbot, Devon-
shire." Quart. Joum. Geol. Soc.y vol. xxxii, p. 230.

1887. .—"Geology of England and Wales" (Second

Edition), pp. 130, 196, 233, 442, 494, 545. (References will here be
found to the works of earlier observers.)

pRoc. Geol Assoc, 1900.

Vol. XVI, Platk XII

Fig. i.-Bovverman's Nose, near Lustleigh.

{From a Photograph by H. Preston, F.G.S.)

Fig. 2. — Lignite Pit, North of Preston, Kingsteignton.

(From a Photograph by A. K. Coomara Swjitiy, F U.S.).

443

EXCURSION TO WIMBLEDON AND KINGSTON.

Saturday, April 28th, 1900.

Directors: W. Whitaker, B.A., F.R.S. (President); H. W.
MoNCKTON, F.L.S., V.P.G.S. ; and W. P. D. Stebbing, F.G.S.

Excursion Secretary : PERCY Emary, F.G.S.
(^Report fy H. W. MONCKTON.)

The members assembled at Wimbledon Station at 2.45, and,
walking to the top of the hill, were there joined by several cyclists,
who throughout the day followed the leadership of Mr. Stebbing.

There have for the last few years been very few sections on
Wimbledon Common ; indeed I have not seen a good one since
November, 1892, when some drainage works at its south end
(level, 175 ft. O.D.) showed a fair section in the gravel which
caps it There is, however, a small gravel pit a little north of
Csesar's Camp, close to the figure 169 on the one-inch Survey
map, New Series, and this was the first section visited. It showed
some 5 feet of yellow and brown, very sandy, current-bedded
gravel, composed of the same classes of material as the gravel
on Kingston Hill described later on. Attention was drawn to the
very flat surface of the Common, and the walking party then
proceeded to cross the valley of the Beverley Brook by a footpath
to Kingston Hill, the cyclists following Mr. Stebbing by a different
route. We had not time to visit the small gravel pit near Warren
Farm, though we saw it in the distance. I, however, have
examined it on several occasions, and found the gravel to be well
stratified, and similar in composition to the sheets which cap the
adjoining plateau and Kingston Hill, and I have no doubt that it
is formed of debris from the older gravel

The section at Coombe Warren (referred to in the Quart Journ,
GeoL Soc.^ vol. xlix, p. 317) is not now open, and we continued
our way to the large gravel pit at the top of Kingston Hill, which
has long been worked for road metal, and was last examined by
the Association on June 12th, 1880 (proceedings, vol. vi,
p. 370 ; " Record of Excursions," p. 83).

The section is a very fine one, and shows some 20 feet of very
well stratified gravel, beautifully current-bedded in many places, and
often very sandy. Several large patches of sand were pointed out
by the President as being evidently re-arranged Bagshot Sand. It
seems to me that in the older geological history of our country we
should scarcely be able to match this deposit. Apart from other
differences, the presence of a large proportion of subangular
stones distinguishes it from the Eocene gravels of Bournemouth,
from the Oldhaven Beds, from the Bunter Beds, etc. Possibly
some of the gravels in the west, classed by Mr. Clement Reid as

Proc. Geol. Assoc, Vol. XVI, Part 8, July, 1900.

444 EXCURSION TO WIMBLEDON AND KINGSTON.

of Bagshot age {Quart fourn. GeoL Soc,, 1896, vol. lii, p. 491),
approach this deposit more nearly, and may have a similar origin.
This gravel is not a solitary example; it is a good representative
of a class of deposit found at many levels and over a wide area in
the southeast of England.

The explanation of the peculiarities of these deposits may be
that they were formed during a period of elevation, whereas most
of our geological formations are the product of periods of more or
less prolonged depression of the land. A chief feature of these
gravels is the flat top, of which Wimbledon Common is an
admirable example.

A flat usually means a water surface, and in this neighbour-
hood we have two flats, viz., Wimbledon Common (183 feet O.D.),
and Ham Common (30 feet O.D.). In other parts of the Thames
Valley there are more than two.* Now a series of flats in the
form of step-terraces is a common occurrence in Norway, and I
am inclined to attribute the gravel flats to the same cause as
the step-terraces, viz., short periods of rapid elevation with long
intervening periods of repose, the step or the flat marking the
period of repose.

In soft strata like that in this part of England, rivers, during a
period of repose, attain a low gradient. Thus the Thames crosses
the 100 feet contour a little below Henley and the 50 feet
contour above Staines. The result of elevation of the land
would be that the rivers would begin to cut new and deeper
channels through the soft strata over which they flow, and thus
the effect of elevation would, apart from obstructions such as
dams or weirs, extend far inland. On a pause in the process of
elevation deposition would begin, and a result of the velocity of
the current would be a tendency to deposit large material, and
such is often found at the bottom of these gravels. There would
then be a deposition of well stratified current-bedded gravels such
as these on Kingston Hill, and eventually, as the river course
attained a low gradient, the coarse gravel would be covered by
brick-earths and fine sand.

The large stones are, in fact, very often at the bottom of a
gravel, but not always. I have recorded {Quart, fourn, GeoL
Soc.f vol. liv, p. 1 89) a sarsen in the middle of gravel on Chobham
Ridges, and at Kingston we saw a reddish pebble (probably
from the Bunter Pebble Beds), with a diameter of 6 inches, in
the gravel 3 feet above the floor of the working, which was some
height above the bottom of the gravel. The stone was 7 feet
below the surface of the ground.

The fine grained deposit at the top of gravel is a very common
occurrence. I have seen examples at all sorts of levels, from 600
feet above the sea at Caesar's Camp, Aldershot, downwards.

• See Quart. Joum. GeoL Sac., vol. xlviii, p. 31, Fig. i, and Whitaker's **Geology.of
London," vol. t, p. 391.

VISIT TO THE BRITISH MUSEUM. 44S

Further, it is very usual to find the lower part of a bed of
gravel evenly stratified, and the upper part much more irregular
with many contortions and long furrows. This I attribute to the
fact that during the stages shortly following an elevation of the
land water flowed rapidly, and deposited the well stratified gravel,
whereas during the subsequent period of a stationary land-level
changes of river-course occurred from time to time, and the
river-ice of the winters made its mark.

The gravel of Kingston Hill is composed of subangular
flints, both brown and black, but mostly the former; of flint
pebbles, probably from Bagshot Beds of the immediate neigh-
bourhood ; of Lower Greensand fragments, which are abundant ;
and of a varied collection — quartzite and sandstone pebbles,
many of which are probably from the Bunter Beds ; small quartz
pebbles, etc.

Leaving the pit, the members proceeded to the Albert
Hotel, Kingston Hill, where tea was provided.

After tea, on the proposal of Captain Stifle, a vote of thanks
was given to the Directors, and the party entered Richmond
Park, and, by the kind permission of the Ranger, visited the
gravel pit near Thatched House Lodge. This completed the
work of the afternoon, and the members dispersed, some walking
through the park to Richmond.

REFERENCES.

Ordnance Map, New Series, Sheet 270.

Geological Survey Map, Sheets 7 and 8. Drift Edition.

1880. LOBLEV, J. L. — " Excursion to Kew Gardens, etc., and Kingston Hill."
Proc. Geo/. Assor.^ vol. vi, p. 370.

1889. Whitaker, W.— •' Geolo|?y of London," vol. i, pp. 269, 425.

1890. Prestwich, Joseph.— '* On a Southern Drift." Quart. Journ, Geol.

Soc.^ vol. xlvi, p. 159.
1893. MoNCKTON, H. W.— •* Pebbles from the Glacial Drift." Quart. Journ,

Geol. Soc.y vol. xlix, p. 316.
See also several recent papers relating to the Thames Valley by H, J. O.
White, A. E. Salter, and Prof. W. M. Davis.

VISIT TO THE BRITISH MUSEUM (NATURAL

HISTORY).

Director: Lazarus Fletcher, M.A., F.R.S.

Saturday, March 17TH, 1900.

The members assembled in the Pavilion at the end of the Mineral

Gallery, at 2.30 p.m. Mr. Lazarus Fletcher, M.A., F.R.S.,

Keeper of the Department of Minerals, drew attention to the

Meteorites in the collection which have a special interest in the

history of the subject, indicated their more salient characters, and

explained to some extent the modes in which such characters have

been produced.

446

EXCURSION TO HITCHIN AND ARLESEY.

Saturday, May 5TH, 1900.

Director : William Hill, F.G.S.

Excursion Secrtiary : A. K. COOMARA SWAMY, F.G.S;
(^Report by The DIRECTOR.)

The party arrived at Arlesey (Three Counties Station) at a little
before three o'clock, and proceeded at once to the large Gault pit
in Messrs. Beart and Co.'s brickyard. On the eastern side of this
pit a section was seen which included the lower 10 ft. of the Chalk
Marl, the thin Cambridge Greensand, and the Gault, The
Cambridge Greensand was only exposed for some 12 or 15 yards,
the bed having been thoroughly worked out in this district for the
coprolites it contained, which in the heyday of agriculture were in
great demand for making artificial manures. The few yards now
seen had been preserved by an old kiln, which it did not pay
to remove when the coprolites were dug.

The President pointed out that the bed was evidently a line of
erosion ; though the base of the Greensand was sharply marked
the upper surface of the Gault on which it rested was uneven. It
contained two sets of fossils, one derived from the Gault, and the
other indigenous to the bed itself; the latter more closely
related to the Chalk than to the Gault fauna. The bed passed up
gradually to the Chalk Marl, and was regarded as the base of the
Chalk. Members were able to obtain a good view of this
interesting bed now so rarely seen ; below it the large pit at
the brickworks exposed some 50 ft. of unfossiliferous Gault.

The quarry of the Arlesey Cement Works was next visited.
The upper part of the Chalk Marl, together with the Totternhoe
Stone and some 10 or 15 feet of the chalk above it were exposed.
The Director pointed out that the Chalk Marl was here about
70 feet thick ; the bluish-grey marl seen at the base of this quarry
was the upward continuation of the whiter marl above the Cam-
bridge Greensand. There was a considerable difference in the
two marls : that just above the Greensand contained only 26 per
cent, of argillaceous (insoluble) matter, while the bluish-grey marl
contained 46 per cent. It was seen that the bluish-grey marl
passed rapidly upward into a whiter and more calcareous deposit.
The aspect of the Totternhoe Stone seen in the quarry was some-
what different from that at Totternhoe. At Totternhoe there is
some 30 feet of evenly grained stone, suitable for building purposes,
while here the stone consists of two beds of rather rough and
rugged sandy (shelly) chalk, together about 12 feet thick. The
bed forms the upper limit of the Chalk Marl, and above it is the
zone of Holaster subglobosus.

But few fossils were found in this quarry during the visit of the

Prog. Geol. Assoc, Vol. XVI, Part 8, July, 1900.]

EXCURSION TO HERTINGFORDBURY, BAYFORD, ETC. 447

Association, though in the experience of the Director it had
proved exceptionally interesting from a collector's point of view.

Leaving the quarry the party took the high ground, walking
along a field-way in the direction of Hitchin. From a command-
ing position the Director drew attention to the fact that the whole
outcrop of the Cretaceous series, from Lower Greensand to Upper
Chalk, was in view. The President remarked that the outcrop of the
Gault in this district is some miles wide, while in Surrey that out-
crop is less, and often very much less, than a mile wide, this being
due to the steeper dip of the beds in Surrey.

On gaining the high road the party proceeded over Wilbury Hill
towards Hitchin, crossing the old "Icknield Way" at right angles,
the Director drawing attention to some facts of antiquarian interest.
They then visited a small but very typical exposure of the Mel-
bourn Rock and after a brisk walk arrived at Hitchin at 6.30 p.m.

After partaking tea the members separated, those who had not
already seen the freshwater deposit at the Folly, Hitchin, joined
the Director in a visit to this interesting section. It has already
been described in the Proceedings,* but since the last visit of the
Association Mr. Clement Reid has investigated the bed, and the
results of his work are published in the Proc, R, Soc,^ vol. Ixi,
p. 40 (1897), reprinted in Trans, Herts, Nat, Hist, Soc,^ vol. x,
pt. i, pp. 14-22 (1898).

Other members visited some interesting gravel pits, or spent
their time in the quaint old town of Hitchin. Joining again at
the station the party returned to town by the 8.24 p.m. train,
having spent a most enjoyable afternoon.

REFERENCES.

Ordnance Survey Map, New Series, Sheet 221.
Geological Survey Map, Sheet 46, N.E.

1875, Jukes-Browne, A. J. — "On the Relations of the Cambridge Gault
and Greensand.'* Quart. Journ. Geol. Soc,^ vol. xxxi, p. 256.

1886. Hill, W., and Jukes-Browne, A. J. — "The Melbourn Rock."

Quart, Journ, Geol. Soc, vol. xlii, p. 216.

1887. , — "On the Lower Part of the Upper Cretaceous Series in

West Suffolk and Norfolk." Quart. Journ, Geol, Soc.^ vol, xliii,
p. 544-

EXCURSION TO HERTINGFORDBURY, BAYFORD, AND

BRICKENDEN GREEN,

Saturday, May iqth, 1900.

Director-, A. E. Salter, B.Sc, F.G.S.

Excursion Secretary: A. K. COOMARA SWAMY, F.G.S.

(Report by The Director)

The party arrived at Hertingfordbury Station (G.N.R.) about

2.30 p.m., and immediately set off to visit two large pits showing

gravel and clay resting upon Chalk. Owing to the presence of pipes

• VoL xiv, pp. 4X5MI9-

Proc. Geol. Assoc., Vol. XVL, Part 8, July, 1900.]

44^ EXCURSION TO KSRTINGFORDBURY, BAYFORD, ETC.

in the chalk the overlying gravel and clay were disturbed in places.
The Director stated that the deposit was about 200 ft. O.D., or
rather more than 50 ft. above the Lea, and consisted mainly of
flint in various forms, together with a noticeable proportion of
foreign material, among which were varieties of dolerite and
rhyolite of uncertain origin, and many Bunter pebbles. Jurassic
debris was absent or very rare. The gravel was capped by a
chalky clay, probably redeposited. This deposit seemed to be
derived from Eocene and older Drift beds, and was formed
during the excavation of the valley between the Chalk ** cuesta "
to the north and the " mesa " about to be visited on the south.

More chalky clay and Glacial sands were seen on the road
leading up to Bayford, and the Director drew attention to the
presence of such deposits at various heights in the Lea Valley,
and questioned their utility as a geological datum line.

At Bayford (300 ft O.D.) some old workings in High-Level
Drift (Westleton Shingle of Prestwich) were examined, and their
contents contrasted with those seen at Hertingfordbury. Flint
and quartz pebbles are plentiful ; radiolarian chert, jasper, schorl
rock, and other foreign j)ebbles occur. Similar deposits are
to be seen at other places on this plateau, and many of the
constituent pebbles are singularly like those found in deposits at
much higher levels in Derbyshire and in the south-west of England,
pointing to the former existence of much larger drainage areas
than there were at present A large dolerite boulder, obtained
while sinking a well, was examined and its microscopic structure
described.

Near Brickenden Green another high-level deposit was seen.
It consisted mainly of flint and quartz, but a good deal of I-X>wer
Greensand chert was seen, which pointed to its having been,
partially at least, derived from the south or south-west possibly
before tectontic movements of considerable extent had occurred.

At Brickenden Green more dolerite boulders were seen, and
on the road to Hertford some interesting sections in a deeply-cut
stream course were examined.

After tea the President called for and obtained a hearty vote
of thanks to the Director, and the party soon afterwards returned
by train to London.

REFERENCES.

Ordnance Survey Map, New Series, Sheet 239.
Geological Survey Map, Sheet 47.

1889. Whitaker, W. — '* The Geology of London," vol. i, Mem. GeoL

Survey.

1890. Prestvvich, Sir J.—" On the relation of the Westleton Beds of

Suffolk to those of Norfolk, and on their extension inland." Quart,
Journ. GeoL Soc , vol. xlvi, p. 84.
1896. Salter, A. E. — " Pebbly Gravel," etc. Proc, GeoL Assoc., vol, xiv,
p. 389-

449

NOTES ON THE GEOLOGY OF THE
ENGLISH LAKE DISTRICT.

B^ J. E. MAUR, KLA., F.ILS.
(Remd Jufy 6ik, 1900,)

A.— IXTRODUCTIOX,

THE Coundl of your Asscxnation has done me the honour of
inviting me to act as Director of an excursion to Lakeland in
the course of the summer. In these circumstances, as I have been
engaged in studying the geology of the district for many years, and
. have arrived at certain conclusions which have not hitherto been
published, I may be pardoned if I incorporate among notes which
may serve to give some idea of the general structure of the
district, a summary of such conclusions; especially as, in my
opinion, a knowledge of them is requisite to a right understanding
of the actual structure.

For several seasons I have had the pleasure of working in
Cumbria with my colleague, Mr. Alfred Harker. Many of the
facts and conclusions recorded in this paper are the result of this
joint work, and my colleague shares with me the credit for any
records which may be of value. I shall endeavour in the paper
to point out clearly such portions as must be r^arded as the joint
work of Mr. Harker and myself. I have obtained his permission to
give this brief preliminary outline of the results of our work, and
should any errors be found therein I ask that I alone may l>e
considered responsible for them.

It is well-known that the heart of Lakeland is composed of
Lower Palaeozoic rocks, and that around these is a girdle of later
deposits of Carboniferous, Permian, and Triassic ages.

The sub-division of the Lower Palaeozoic rocks into three
great natural lithological groups was first made by Jonathan Otlcy,
in a paper in the Lonsdale Magazine (vol. i, 1820, p. 433), and
this tripartite grouping has been always recognised by subsequent
writers, though the names applied to the groups vary in different
memoirs. The following table will show the nature of the rocks :

Upper Slates (with Coniston Limestone at base), flags, grits,
and slates.

Middle Slates ("Green Slates and Porphyries," "Borrodale
Series "), volcanic rocks.

Lower Slates (Skiddaw Slates), dark argillaceous rocks with
interbedded grits.

As regards the geographical distribution of these divisions,
(leaving minor complications out of account for the moment),
it may be stated that the axis of uplift of the main anticline

Proc Geol. Assoc., Vol. XVI, Part 9, Aucirsi, 1900] 34

450 J. E. MARR ON THE

into which the slates are folded runs through Skiddaw in an
E.N.E.-W.S.W. direction, and that the Lower Slates or Skiddaw
Slates are developed to the north and south of this axis. On
the north side they are succeeded by a narrow and somewhat
remarkable band of the " Middle Slates " (here only styled slates
for convenience) which runs from near Greystoke Park, a few miles
west of Penrith, to Cockermouth. The southern boundary of the
Skiddaw Slates, where they are again succeeded by the Middle
Slates (or Green Slates and Porphyries), commences on the east at
the north-east or lower end of Ullswater, is traceable thence
to the south end of Derwentwater, thence past Buttermere and
Ennerdale Lakes, and on to the neighbourhood of Egremont, on
the west of the district. The junction between Middle and Upper
Slates is well defined by the Coniston Limestone, which, starting
near Shap, strikes across the heads of Windermere and Coniston
Lakes, and then past Broughton Mills, to the south-west of
Cumberland at Millom.

The actual age of most of the deposits, owing to comparative
rarity of fossils, was for a long time a matter of dispute, and even
at the present day the geological horizon of some of the groups
of rocks can scarcely be regarded as settled.

For many years there was a general consensus of opinion as
regards the general age of the three main groups above noticed.
The Skiddaw Slates, on account of the nature of their included
organisms, were referred to the Arenig epoch; the middle division
was considered to be of the Llandeilo epoch ; while the upper
division was believed to have representatives of strata from
Caradoc to Ludlow, both inclusive. As the result of detailed
study of the fossils the correctness of the last correlation has
been firmly established, but doubt has been thrown on the other
two, and especially upon the second. I shall attempt to show,
however, that in each case the reference is mainly correct.

The attention of the visitors to Lakeland in August next will
be chiefly called to the Lower and Middle series of slates, which
are well developed in the neighbourhood of Keswick, the head-
quarters of the party ; and it will be necessary to pay special
regard to the character of these two groups. In so doing I shall
assume that the reader will peruse these notes with the aid of the
published maps of H.M. Geological Survey.

Keswick is situated some way north of the centre of Quarter-
sheet loi S.E. (Sheet 29, New Series), and it is over the ground
represented in this quarter-sheet that most of the excursions will
be conducted, though one will be largely on ground represented
on the Quarter-sheet lying immediately to the east (102 S.W.,
Sheet 30, New Series).

N.B. — Members will find a geological map of the district
facing p. 528 of the "Record of Excursions."

GEOLOGY OF THE EXGUSH LAKE DISTRICT, 45 1

B.— DESCRIPTION OF LOWER PAL-i^OZOIC ROCKS.
I. — The Skiddaw Slates.

Distribution, — The extent of the main mass of Skiddaw Slates
has already been noticed. It is important for our purpose to
note, in addition, the occurrence of other outcrops. In the neigh-
bourhood of Ullswater an isolated patch is separated from the
main mass by the conglomerate of Mell Fell, to be referred to
subsequently ; beneath this it probably continues to join the
main mass. South of the Ullswater patch is an extensive patch
stretching from the hamlet of Butterwick to the vicinity of Shap.

In the Lower Palaeozoic inlier of the Cross Fell range, east of
Eden, is a continuous patch of these slates, stretching nearly the
entire distance of that outlier. In the extreme southern extremity
of Cumberland an isolated outcrop of Skiddaw Slate forms the
hill known as Black Combe, and a smaller patch occurs on the
opposite side of the Duddon estuary, to the north of Dalton-in-
Furness. The significance of these outcrops to the south of the
main mass will be eventually considered.

Lithological Characters, — There is a general sameness in the
characters of the whole group, though the rocks often differ con-
siderably in detail. Shales, slates, and grits are the dominant
rocks, and detrital mica is usually abundant. Carbonate of lime
is practically absent, except in mineral veins traversing the rocks.
The shales vary in colour from bluish-grey, or sometimes greenish-
grey, to black. In texture they may be hard and splintery, or
soft and earthy. Many of them are cleaved, though they never
give rise to roofing slates of such utility as those of the Middle
Slates ; in other places cleavage is absent, and this is especially
marked in the more northerly part of the main expanse.

The grits are very variable. Some, like the " Skiddaw Grit,"
are coarse quartzose rocks, sometimes becoming conglomeratic ;
others are much finer and are often laminated. These contain
varying proportions of muddy matter, and so pass gradually into
the shales and slates. Many of the arenaceous beds seem to be
affected by true ripple-marks, and were probably deposited in
shallow water, though in other cases structures simulating ripple-
marks seem to have been caused by subsequent movements.

The presence of volcanic rocks in the upper part of the
Skiddaw Slates is a fact of considerable interest. Mr. Clifton
Ward inserts intercalated volcanic rocks in the beds near the
contact with the Middle Slates, at the Hollows Farm, near
Grange, in Borrodale, and at the south-west end of Crummock
Lake. Other volcanic rocks are intercalated with the higher
Skiddaw Slates of the neighbourhood of Shap, and also in those
of the Cross Fell inlier.

452 J. E. MARR ON THE

With our present knowledge, any attempt to subdivide and
classify the Skiddaw Slates by reference to their lithological
characters only, would be premature.

The thickness of the group was estimated by Mr. Clifton Ward
as at least 10,000 or 12,000 feet. As will be seen presently,
however, it is very difficult to judge of the amount of repetition
which may have occurred owing to subsequent folding and
faulting.

^g^ of the Slates : the Fossil Evidence, — The occurrence of
fossils in these slates has long been known ; of recent years the
number of recorded species has been largely increased, owing
mainly to the work of assiduous local observers, of whom special
mention may be made of the late Mr. Kinsey Dover and Mr. J.
Postlethwaite. To the labours of the latter gentleman we may
look forward in expectation of a still further increase in the number
of forms discovered. The latest discoveries confirm the earlier,
and indicate that the main mass of the y^j«7//5?r^;/j Skiddaw Slates
is of Arenig age, though some Tremadoc forms probably occur, and
possibly also some Llandeilo species. This conclusion is reached
by Miss Elles, the latest student of the Skiddaw Slate fauna. The
fossils, however, are by no means uniformly distributed through
the slates. They are commonest in, though by no means confined
to, the black slates, especially those of an earthy texture. More
important is the fact that the fossiliferous bands often run in
linear belts. The most marked commences in the upper part of
the Glenderamakin Valley, is traceable along the ridge of Saddle-
back, and is possibly continued on the west side of the Derwent
Valley, crossing the lower part of the Whinlatter Pass, forming the
top of Grizedale Pike, and reaching Whiteside, near the foot of
Crummock. On either side of these belts of fossiliferous rock lie
the great grit bands, and at present there is no evidence as to the
age of the latter, except that, for reasons to be given later, they
can hardly be newer than the fossiliferous Skiddaw Slates, and as
the latter are not likely to alter their characters so rapidly when
traced across the strike, they are probably not contemporaneous
with them. The probability, therefore, is that they are older,
though how much older one cannot say. It is to be hoped that
local observers will examine these rocks very carefully, and
endeavour to find fossils in some of them.

Next to the Graptolites the Trilobites are the most abundant
fossils hitherto discovered. Most of these appear to belong to the
higher beds of the Skiddaw Slates, and the assemblage is essentially
one which recalls that characteristic of the fauna of Dr. Hicks*
Llanvirn group. In this connection it is interesting to recall the
record by Mr. Kynaston of Piacoparia, a form more frequently
discovered in Central European rocks of this age, though also
found at St. David's.

GEOLOGY OF THE ENGLISH LAKE DISTRICT. 453

II. — The Greex Slates axd Porphyries or Volcanic
Rocks of Borrodale.*

I specially wish to retain the title "Green Slates and
Porphjrries" for these beds, not only as really \"er)' descriptive,
but because the alternative title introduces the name of a locality
where the series is by no means typically developed. Mr. Marker
and I recognise the following divisions among the volcanic rocks
of this series, which are given in descending order :

Shap Rhyolites.
Shap Andesites.

Scawfell banded ashes and breccias=Kentmere-Coniston Slate
Band.

Ullswater basic lava group=Eycott group.
Falcon Crag and Bleaberry Fell Andesites.

This division does not differ very notably except in detail from
that given by Mr. Clifton Ward in his Horizontal Section, No 3,
illustrating his paper " On the Physical History of the English
Lake District" {GtoL Mag,, Dec. II, vol. vi, p. 54).

We have reasons for believing that the Yewdale breccia belongs
to the series of Shap rhyolites, and is separated from the rocks on
the summit of High White Stones by the Shap andesites. The
divisions A, B, and C of Mr. Ward's section just mentioned,
on High White Stones, we refer to the Scawfell ashes and
breccias. D, E. F, and G partly correspond with the Ullswater
lavas, but the main mass along the line of section consists
of flinty, often streaky rocks, frequently containing felspar crystals
of considerable size, and also furnishing, in many places,
abundance of garnets. Of these rocks more will be said anon.
Lastly group H contains the Falcon Crag and Bleaberry Fell
andesites, though the lower part of the basic group may be
included in it, along the line of section ; the section, however,
is on too small a scale to enable us to judge of this with certainty.

The following section from Derwentwater to Coniston
(Fig. i) shows the relationship of the different divisions :

description of the main characters of the different

GROUPS, and of their GENERAL DISTRIBUTION.

(i.) Falcon Crag and Bleaberry Fell Andesites, — These rocks
were selected by Mr. Ward as typical of the lavas and ashes, and
were very fully described by him in the memoir of "The Geology
of the Northern Part of the English I^ke District," pp. 13-19.
They form a syncline between the Valley of St. John and that in
which Derwentwater is situated, and extend from the junction with

• This description of the volcanic rocks (II.) must be regarded as the joint work of Mr.
Harker and myself, though I alone am rcnponsible for the manner in which it Is given.

454

J. E. MARK ON THE

vj u, iJ t/3 cc

the Skiddaw Slates on the
north to the neighbourhood
ofWatendlath Tarn on the
south. It is doubtful
whether they are represented
in any other part of the dis-
trict, though some of the
lower rocks just above the
junction with the Skiddaw
Slates between Shap and
Ullswater may appertain to
them, for lavas from Pooley
Bridge, and Crag's Mill,
Shap, give silica percentages
of 5 8* 65 and 61*95 respec-
tively. A condensed de-
scription of the rocks may
also be found in a paper
"On the Geology of the
Neighbourhood of Keswick,"
written with reference to
the last excursion of the
Association to the district
by your then President,
Mr. W. H. Hudleston.-

The individual lavas, on
the whole, are rather thin,
and accordingly vesicular
structure is particularly fre-
quent. They are associated
with ashes and breccias.
(The nature of the basal
purple breccia will be dis-
cussed later.) The lavas
are usually of intermediate
composition, with a silica
percentage of 59 to 61, and
a specific gravity 2*65 to 27,
but it could hardly be ex-
pected that all the lavas
should have a percentage
within these limits, and as
a matter of fact we find that
one of the lavas in Ward's
typical "Falcon Crag Sec-
tion" (probably the base
of his No. 5 lava), has a

* Frvc. Gtol. Assoc., vol. vii, p. 213.

GEOLOGY OF THE ENGLISH LAKE DISTRICT. 455

silica percentage of 5435, thus closely approaching the normal
basic lavas of the district It is expected that further examination
will furnish us ¥rith other basic rocks appertaining to the Falcon
Crag division.

As r^ards the general characters of these intermediate lavas
"they are pyroxene-andesites, the pyroxene being sometimes a
rhombic one (hypersthene), sometimes a monoclinic (augite), or
the two often occurring together. These minerals are not in
crystals large enough to be easily detected by the eye, though the
dark patches due to their decomposition-products may often be
obser\'ed. Porphyritic felspars are usually present, sometimes
rather crowded and up to a quarter of an inch long, but more
usually scattered, and often minute. The ground mass has a very
compact look, with usually either a pale greenish or dark grey tint.
Many of the flows are vesicular, and the vesicles may reach
considerable dimensions, as, for instance, on some parts of Grange
Fells. They are commonly filled with chalcedony, agate, calcite,
chloritoid substances, etc., in concentric layers.

"Some of the andesites have a special character in the
occurrence of little red garnets.*'*

The lavas and ashes of this group are of interest on account
of the slight changes which they have undergone as the result of
subsequent earth movements, except towards their southern
extremity. The ordinary features of volcanic rocks may accord-
ingly be readily studied in them. Many of the lavas show
marked tabular jointing, as, for instance. Ward's No. 4 on
Falcon Crag, and a lava which is seen on the roadside between
I^wdore and Grange. Ward records garnets in the ash inter-
vening between his lavas i and 2 on Falcon Crag. They are
v:r>' minute.

(ii.) UUswater Basic Group^^Eycott Group, — We have
adopted the name UUswater Group for this series of volcanic
rocks, as they are extremely well developed among the hills around
the upper part of UUswater. They appear, however, to be the
most widely distributed of all the divisions marked by presence
of abundant lava flows, though the area covered by them may
perhaps be exceeded by that occupied by the Scawfell ashes and
their equivalent slate band to the south. The detection of this
UUswater group is a matter of considerable importance as
throwing light upon a matter which has puzzled previous writers,
namely, the whereabouts in the main development of the (ireen
Slates and Porphyries of the equivalents of the well-known
Eycott Hill volcanic rocks which occur on the northern side of
the great Skiddaw anticline.

These Eycott rocks, which sweep round from Eycott Hill,

• Barker, A —"The Ancient Lavas of the Enelish Lake District," The Naturaiist^^
May. 1 391. See also papers by the same author, " Chemical Nutexon Lake District Rucks,"
Ibid., February and May, 1S99.

456 J- E. MARR ON THE

near Greystoke, on the north side of Carrock to the neighbour-
hood of Cockermouth, form the subject of a special memoir by
Mr. Clifton Ward.* "They contain 51 to 53 per cent, of
silica, and have a specific gravity of about 275." " Unlike most
lavas of similar chemical composition they contain no olivine,
but instead we find other basic minerals abundant, and particu-
larly hypersthene ; so that the rocks may be termed hypersthene-
basalts."t The very striking lava occurring near the base of the
group at Eycott Hill is well known. It contains large crystals of
bytownite felspar, an inch or even two inches across.

We first detected the basic series of lavas and their associated
fragmental rocks in the area of main development of the Green
Slates and Porphyries while studying the phenomena connected
with the metamorphism produced by the Shap Granite, but
further study soon showed us the wide extent over which these
rocks occurred. They are abundantly seen around Haweswater,
where they present striking similarities to the typical lavas of
Eycott Hill, and anyone studying the lavas of the Haweswater
region would be at once convinced of the general identity of
these with those of Eycott, even apart from chemical and micro-
scopic study. One of these lavas of the Eycott type, with large
felspar phenocrysts, from Randal Beck, Mardale, has a silica
percentage of 53*45, with specific gravity 2736. As already
remarked, they are extremely well developed around Ullswater,
and may be traced over Helvellyn to the Vale of St. John. In
Borrodale they do not appear in great force on the east side,
though the members of the Association will probably have an
opportunity of seeing them at Gall en y Force, at the foot of
Greenup Gill (a specimen from this locality has a silica percent-
age 52*6, and sp. gr. 2757). On the west side of Borrodale they
appear to be developed in force, and may be traced hence over
Honister Pass (where the workable slates are associated with
them), and thence by the head of Ennerdale to Wastwater, where
ihey are again developed in considerable force. On the south
side of the great mass of Scawfell ashes, which occupies the central
part of the district, they are developed in the narrow band of
country between these ashes and the equivalent slate band which
runs from near Shap to Coniston, as seen in the Section (Fig. i;.

There is considerable variation among the lavas of the group.
The large porphyritic felspars, which are so prominent in some
of the Eycott Hill rocks are fairly frequent, but in the greater
number of lavas which contain phenocrysts, these are of a ferro-
magnesian mineral and not felspar. Many of the features which
are observable in the andesitic group are also noticeable here ; in
fact the similarity is usually so great that it would be difficult to

• •' On the Lower Silurian Lavas of Eycott Hill, Cumberland," by J. Clifton Ward.
Monthly Microscopical J oumaly 1877.

t Harker, Alfred, Tfu Natufaiist, May, 1891.

GEOLOGY OF THE ENGLISH LAKE DISTRICT. 457

separate the two groups from one another without having recourse
to chemical analyses. A considerable number of these have been
made (or, at any rate, silica percentages determined), and are
recorded in the paper in The Naturalist to which reference has
already been given.

(iii.) Scaw/ell Banded Ashes and Breccias^ and Kentmere-
Coniston Slate Band. — The presence of very fine and well bedded
ashes is by no means characteristic of this division ; indeed, we are
accustomed to meet with them in every division of the Green Slates
and Porphyries, and their presence in the Honister rocks has just
been alluded to. The reason for separating the present division
from others is the great development and preponderance of ashes
therein, lavas being few in number and only locally developed.
The Scawfell ashes are typically developed in the Scawfell group,
and it is there that the members of the Association will have an
opportunity of studying them. They practically form the water-
shed between the rivers flowing north and those flowing south
in the heart of the district. In the east, they are first found on
the spur of the High Street range which separates Haweswater
from UUswater. From High Street a tongue is sent off* past
Mardale to the east side of Haweswater. The main mass con-
tinues westward, forming the great mass of Fairfield, Red Screes,
and the upper part of Helvellyn, whence a tongue runs to the
head of UUswater. It is cut through by the Dunmail Raise Pass,
but the ashes set in on the west side of that pass, and are continued
by High White Stones to the Scawfell group. Here they trend
southward to the Coniston chain, being again cut through by
Wrynose Pass. They form the summits of the Coniston Fells,
and here send ofi" a third tongue into the Duddon Valley.

Returning to the neighbourhood of Shap, we meet with a
workable slate band in the valley of Mosedale, west of Shap
Wells. This is readily traceable in a series of quarries, and runs
by Long Sleddale, Kentmere, and Troutbeck, and along the fells
at the heads of Windermere and Coniston Lakes to a point near
the village of Tor\'er, where it suddenly abuts against the Coniston
Limestone. The ashes of this slate band appear at first sight
very different from those of the Scawfell group, but we were soon
convinced of their general identity, and afterwards obtained con-
clusive evidence on this point. The two seem to run together on
Red Screes ; but the most striking evidence is seen at Walney
Scar, west of Coniston Lake, where the slate band and Scawfell
ash group come together, and can be actually traced into one
another, though a remarkably sudden change in the lithological
characters of the rocks is noticeable at this place.

I shall here notice only those characters of the group which
appear to be original, leaving the study of the features produced
by subsequent changes for consideration in another section of the
paper.

45^ J- E. MARR ON THE

The most striking feature is the banding of the rocks, which
may be studied on various scales ; the marked bedded structure
is often ^een at a distance, as in the Scawfell group viewed
from near the head of Eskdale, or in the great precipice of
Helvellyn, as seen from Red Tarn. A nearer approach shows
well-marked escarpments and dip-slopes on a smaller scale, due to
minor divisional planes of bedding. These may be studied
between Sty Head and Sprinkling Tarns. On still closer inspec-
tion, finer lines of lamination may often be observed in the ashes,
which are even of microscopic minuteness in the very finest ashes.
There is no doubt that extensive movement has occurred aloni;
many of these planes, but they were obviously bedding planes as
originally developed.

Associated with the finer ashes (the finest of which must have
been showered out as volcanic dust) are breccias of every degree
of coarseness. Many of these are obviously true breccias of
explosion, others as obviously are not, while in many cases it is
impossible to state to what cause a breccia is due. This point
will be considered later.

The composition of the ashes is variable, as might be expected
from the fact that they occur above a basic group of lavas and
below an intermediate group. In the Scawfell area an ash from
the upper part of Eskdale has a silica percentage 63*1 and sp.
gr. 2*755, while another from Hanging Knotts gave silica per cent.
56*60, sp. gr. 2*667. Of two rocks from the slate band, one from
a quarry at Grasmere has a silica percentage of 61*75, ^^^ another
from Tilberthwaite 61*25.

The slates of Troutbeck are associated with thin vesicular
lavas, and lavas are probably intercalated with the ashes in other
localities.

(iv.) S/ia/> Andesites. — A description of these rocks is given
in our paper on the Shap Granite. At Shap they occur in contact
with the Ullswater group, as the ashes of the slate band are here
faulted out, but farther west, as already stated, the ashes of this
slate band come in at Mosedale. The Shap andesites are trace-
able as a continuous band from Shap to the neighbourhood of
Torver, where they, like the beds of the slate band, abut against
the Coniston Limestone, but reappear again near Broughton-in-
Furness.

Outliers of this group appear on several hill-tops above the
Scawfell banded ashes. They are found on the summits of Red
Screes, Helvellyn, and the hills on the east and wesi side of
Langdale.

The lavas are usually thin, and consequently vesicular. A
specimen from between Wasdale Pike and Great Yarlside, west of
Shap Wells, has a silica-percentage 59*95 and sp. gr. 2*736.

(v.) Shap Rhyolit€S. — These rocks are also described in our
paper on the Shap Granite. They extend from Shap to near

GEOLOGY OF THE ENGLISH LAKE DISTRICT. 459

Torver, and reappear in considerable force in the neighbourhood
of Millom. No definite passage can be traced from the rhyolites
which succeed the andesites and those which [are associated with
the Coniston Limestone and with fossiliferous ashes ; but from
their general resemblance, there is little doubt that there was
originally a passage. Many of the rhyolites show remarkable
nodular structures, which are specially well seen on Great Varlside.

III. — The Upper Slates.

A very short account of these rocks will suffice. They are
subdivided into the following groups in descending order :

Kirkby Moor Flags=Upper Ludlow.

Bannisdale Slates ]

Coniston Grits ^ Lower Ludlow.

Upper Coniston (Coldwell) Flags;

Lower Coniston (Brathay) Flags=Wenlock.

Stockdale Shales=Tarannon -f Llandovery.

Coniston Limestone^Ashgill -f Caradoc.

The Coniston Limestone outcrop, as before stated, runs from
Shap Wells to Millom. The group also appears on the east side
of the Duddon Valley, in the neighbourhood of Dalton-in-Furness.
The representatives of the Coniston Limestone are further found
in the Cross Fell inlier. Of particular import is the occurrence
of deposits of this age towards the extreme north of the district,
at Dry Gill, in the Caldbeck Fells. A local unconformity occurs
in the centre of the Coniston Limestone group. Evidences for
this are seen in Stockdale and at High Pike Haw near Torver.

The Stockdale shales are of interest to us in this place, on
account of their lithological characters. They consist of a thin
deposit of soft black shales, succeeded by a thicker mass of harder
beds containing massive grits.

The Brathay flags are fine-grained, as are the Coldwell beds
to a great extent, while the Coniston grits are massive grits with
few argillaceous seams.

The Bannisdale slates consist of finely laminated gritty shales
interstratified with frequent thin grits, and the Kirkby Moor Flags
are gritty flags and grits.

The Upper Slates are developed in the Lake District proper in
the comparatively low ground south of the junction with the
Green Slates and Porphyries. They form also the Howgill Fells
on the east side of the Lune Valley, and travellers to Keswick by
the London and North Western Railway will be able to judge of
their general characters, as they are developed in force between
the stations of Oxenholme and Tebay.

460 J. E. MARR ON THE

C— CHANGES AT THE CLOSE OF LOWER
PAL.COZOIC TIMES.*

(i.) Previous Views on the Structure,

It has long been known that the movements which gave the
prevalent E.N.E.-W.S.W. strike to the Lower Palaeozoic rocks
of Lakeland occurred before the deposition of the Carboniferous
rocks, which are unaffected by these movements, and it has long
been recognised that the apparent structure of the axis of the
district is that of a great anticline, of which the Skiddaw Slates
occupy the centre, while the Green Slates and Porphyries rest
upon them on the north and south, and the Upper Slates rest
upon the Green Slates and Porphyries on the south.

It has also been long recognised that this main anticlinal fold
is complicated by many minor folds and faults ; for many years,
however, these were not considered of sufficient importance to
cause any great difference between the original succession and that
which at present exists.

As the result of the detailed mapping of the members of
H.M. Geological Survey, and especially of the late Mr. Clifton Ward,
it became apparent that the junction between the Skiddaw Slates
and the Green Slates and Porphyries was not a normal one, and
three explanations have been hitherto suggested to account for the
appearances presented at this junction.

1. Mr. Dakyns, in a short paper in the Geological Magazine
(Decade I, vol. vi, 1869, p. 56), gives reasons for supposing that
the junction is an uncomformable one.

2. Mr. Ward represents the junction as a faulted one. The
faults are represented in his sections with fissures approaching
the vertical, and over a considerable distance along the line of
junction, that junction is represented as one consisting of two
sets of faults, one of which is nearly at right angles to the other.
As Mr. Ward remarks in the memoir on the Keswick Quarter-
sheet (p. 48), ** The boundary, in fact, appears to be formed by
the constant meeting of faults having a more or less north and
south direction with others having a more or less east and west
course, the two frequently meeting at right angles with each other,
and letting down the rocks between them."

3. Some years since, the junction was freely spoken of among
geologists more or less acquainted with the district, as being
probably of the nature of an overthrust-plane. I believe this
opinion has received its expression in print, but am unable, at the
moment, to find the reference. As no evidence was adduced in
support of it, the matter is unimportant.

At the time when the first two views were put forward, the
study of the effects of earth-movement was by no means in so

• Section C is a record of work carried out by Mr. Harker and myself. As befw^, I am
responsible for the mode of expression.

geoijogy of the exoush lake district. 461

advanced a state as at present, and in particular, the existence of
reversed faults was supposed to be extremely rare, while faults with
a fissure approadiing the horizontal were practically ignored. In
these circumstances the nature of the junction between the
Skiddaw Slates aiKl the Green Slates and Porphyries was of
necessity a puzzle, and it is not surprising that Messrs. Dakyns
and Ward should have ofifered these explanations. It gives me
much pleasure to bear testimony to the accuracy with which the
main facts were noted by these writers. Both evidently saw diffi-
culties in explaining the actual facts, as they observed them, in
accordance with opinions which were then current, but they
nevertheless did futhfully record these facts, and accordingly gave
most important help to subsequent workers. While on this sub-
ject I would also bear witness to the extreme accuracy of
Mr. W. T. Aveline's maps of the southern part of the district The
views which we put forward would not have been arrived at so
soon, if at all, had it not been for our study of the published maps
of the Geological Survey, and we feel it only right to e.xpress an
acknowledgment of the assistance which we have received from
these maps, and their accompanying sections and memoirs.

(ii.) General Statement of our Vicivs,

(a) It is our opinion that the present succession of the rocks
in the district is, on the whole, the original one ; that the Skiddaw
Slates are succeeded in order by the Green Slates and Porphyries,
and these by the Upper Slates. We find no evidence that the
Green Slates and Porphyries are older that the Skiddaw Slates,
and have been thrust over them along a thrust-plane.

(p) We consider that the folding and faulting which have
affected the Lower Palaeozoic rocks of the district are primarily
due to the pushing forward of the rocks in a general northerly
direction by a force acting from the south.

{c) Further, that the rocks moved forward at unequal rates,
and that, so far as the main mass of rocks now exposed is con-
cerned, the Skiddaw Slates moved farthest forward, causing the
Green Slates and Porphyries to lag behind, and the Upper Slates
in turn to lag behind the Green Slates and Porphyries.

{d) As the result of the lagging, we believe that a fault, whose
fissure approaches the horizontal, was formed between the Skiddaw
Slates and the Green Slates and Porphyries, and a similar fissure
between these volcanic rocks and the Upper Slates. These
fissures, it will be noticed, would have an outcrop similar to those
of thrust-planes or over-faults which approached the horizontal ;
but they would differ from these, inasmuch as no inversion on a
large scale would accompany them. We shall speak of them here
as " lag " faults.

{e) The slices of rock defined by these greot strike-faults would
be affected by minor folds and faults, which would often abut
against the great strike-faults.

462 J. E. MARR ON THE

(f) We consider that the evidence further shows that each of
these great slices moved forward with different velocity in different
parts. Thus, if the right hand portion of a rock-slice moved
forward more rapidly than the left hand portion, and the rock
would not stretch, it would be fractured, and the right hand por-
tion would be pushed nearly horizontally past the left hand portion
along a vertical or nearly vertical line of fracture. These faults
would be dip-faults, but the displacement would be backward and
forward, and not an upward and downward one. We have been
accustomed to speak of these faults as " tears," and for conveni-
ence may use the term here, for the rocks are torn from one
another. These " tears " correspond in some respects with the
minor thrusts occurring between the main thrust-planes in a
district which has been affected by overthrusting.

(g) Owing to these movements the rocks of the district would
be broken up into rectangular or rhomboidal blocks, in each of
which two sides would be defined by strike-faults and the other
two by dip-faults.

(K) If this general thrusting in a northerly direction took place,
we should find signs of overthrusting somewhere to the north, for
the rocks travelling onward must have travelled over some other
rocks. There seems no evidence of the extensive outcrop of the
overthrust in the I^ke District proper, but evidence points to the
possibility of the Drygill Shales being beneath the great over-
thrust, and to the same thrust being the plane of separation
between the Skiddaw Slates and the Upper Slates of the Cross
Fell inlier.

(/) Such movement should be marked by many minor
mechanical changes, and possibly also by chemical changes in the
rocks of the district. We propose to offer evidence of the occur-
rence of these changes in a very considerable degree.

(iii.) General Evidence for the Faults.

\a) The Overthrust, — Owing to the paucity of sections, little
evidence can be brought forward in favour of the actual existence
of the overthrust (which must occur somewhere, assuming that
our views are correct) in the present district. The position of the
Drygill Shales is so extraordinary that the late Professor Nicholson
and I were reluctant to place the beds in the position to which
they seemed to belong after study of their fossils, but further
study convinced me that these beds were really of the age of the
Coniston Limestone, and Miss Wood and Miss Elles eventually
proved beyond doubt that this was the case. These shales occur
on the north side of the Carrock Fell igneous rocks, and to the
north of them are rocks of the Eycott group. Their existence in
this position is best explained, on the supposition that they occur
beneath an overthrust, and in confirmation of this, I may point
out that they approach rather to the Scotch type of deposit than
to that which characterises the main line of outcrop of the Coniston

GEOLOGY OF THE ENGLISH LARE DISTRICT. 463

Limestone group. The beds have undoubtedly been affected by
other changes, including intrusion of igneous rock, which may
have carried them to their present elevation.

In the Cross Fell inlier, the junction between the Skiddaw
Slates on the east and the Upper Slates on the west is mapped as
a faulted one. Here again, subsequent changes have occurred as
the result of post-Carboniferous movements, but several facts point
to the existence of the Skiddaws above the Upper Slates. The
Skiddaws occupy higher ground than the Upper Slates, and
the apices of V-shaped outcrops of the fault point up-valley in
Scordale and Pusgill. Again, the eastern slopes of Dufton Pike
and Knock Pike suggest denudation along a fault plane sloping
eastward. Finally, the Upper Slates here are again suggestive
of the Scotch type of deposit.

I would suggest that local observers should make a very
minute search for fossils in the ground lying north of Skiddaw
and in the region around Cockermouth, in hopes of finding
further developments of the Drygill Shales, or of other deposits
appertaining to the Upper Slates.

(d) The ^^Lag" Faults, — As already stated, we consider that
the most important of these faults separate the Skiddaw Slates
from the Middle Slates, and the latter from the Upper Slates.
These may be considered in order, commencing with that between
the Lower and Middle Slates.

It is hardly necessary at the present day to insist on the fact
that the outcrop of the junction-line between the Skiddaw Slates and
the volcanic rocks which now overlie them is that of a fault with
a fissure slightly inclined to the horizon, if it be not that of a con-
formable or uncomformable junction. The absence of conformity
is generally conceded, and need not be further considered. The
absence of an unconformity is not so clearly discernible at the
outset, but the fact that the planes of separation of the different
aiembers of the overlying rocks frequently abut against the plane
of junction of the two groups negatives the occurrence of an
unconformity, and detailed examination of the junction shows an
absence of nearly all the accompaniments of an uncomformity, and
the presence, on the contrary, of those of a fault. It is, therefore,
admitted on all hands that the junction is a faulted one at nearly
every point.

The next thing to consider is the inclination of the fault.
Here again little need be said. Inspection of the junction on
the two quarter-sheet*: to which reference was made at the outset
shows that the line of junction is a zigzag one. The apices of
the V's in the valleys point up valley, and those on the adjoin-
ing hill-ridges in the opposite direction. The constant occur-
rence of this proves at once that we are not dealing with two sets
of faults with highly inclined fissures, but with one gently sloping
fault, for the coincidences of intersection of fault with valley-

464 J. E. MARR ON THE

bottom or ridge-summit are far too numerous to permit of the
former explanation. Again, we sometimes find isolated masses
of Skiddaw Slates projecting through the volcanic rocks, as near
Scarf Gap Pass, Buttermere, or isolated patches of faulted volcanic
rock resting on Skiddaws, as on the north side of Ullswater.

The fault, then, is one of gentle inclination ; it remains to be
seen whether it is an overthrust or a " lag " fault. If the former,
the volcanic rocks must be older than the Skiddaw Slates, if the
latter, they must be newer.

We believe that the view that inversion may occur here
partly arose as the result of a striking resemblance between the
lithological characters of the flinty ashes of the centre of the dis-
trict and certain Pre-Cambrian, or supposed Pre-Cambrian, flinty
ashes in other areas. We hope, however, to show that these
ashes owe their present condition to subsequent changes, and we
can certainly show, in the case of the rocks which occur in Borro-
dale, immediately north of the alluvial flat of Rosthwaite, that
similar flinty ashes, developed on a small scale, are intercalated
with lavas which bear a striking resemblance to Arenig lavas in
other districts, so that the argument as to age derived from the
flinty ashes is directly opposed to that derived from an examina-
tion of the Falcon Crag Series.

Again, there is evidence of the setting in of volcanic activity
at the end of Skiddaw Slate times, of the existence of sediments
of Skiddaw Slate type near the base of the volcanic rocks,
and of the continuation of volcanic activity after the commence-
ment of the Coniston Limestone period. Attention has been called
to the intercalated volcanic rocks in the Skiddaw Slates, and it
remains to be stated that sediments of Skiddaw Slate character
are intercalated with the lower ashes of the Falcon Crag Series
on the left bank of Cat Gill, which descends from near Falcon
Crag. The volcanic rocks associated with the Coniston Lime-
stone Series are seen between Shap and Kentmere, and in the
Sedbergh district.

Furthermore, the volcanic accumulations in the Skiddaw
slates conform very closely in character with the lowest known
rocks of the actual Green Slates and Porphyries, being andesitic,
while the volcanic outpourings amongst the Coniston Limestone
group are similar to those of the top of the Green Slates and
Porphyries, being rhyolitic.

In one place, and one place only, there seems to be a passage
between the Skiddaw Slates and the volcanic series. Above the
Hollows Farm, near (Grange, in Borrodale, green shaly Skiddaw
Slates, with much detrital mica, in which Mr. Harker found a
Lingula, are immediately succeeded by a massive ash of the main
volcanic series. The junction seems to be perfectly conformable,
and specimens may actually be detached with samples of the two
rocks soldered together. It seems inconceivable that this

GEOLOGY OF THE ENGLISH LAKE DISTRICT. 465

junction should be faulted, and we believe that the rocks are here
in their true sequence, and that the main 'Mag" fault has here
left the junction between Skiddaws and volcanics, and locally
shifted to a lower or a higher horizon, or, more probably, has
split, giving rise to a lenticular inclusion.

Proceeding now to the "lag" fault, which separates the
Coniston Limestone group from the underlying Green Slates and
Porphyries, we find some differences between it and that which
has just been described, and the appearances in this case are at
first even more suggestive of unconformity than in the case of the
more northerly fault, especially as an unconformity does exist, as
already observed, in the middle of the Coniston Limestone group.
The fault plane is more highly inclined than that separating
Skiddaws from volcanics, and accordingly the zigzag outcrop is
replaced by a straighter line. Again, though the Coniston Lime-
stone group rests on different members of the volcanic series, as
detected by Messrs. Aveline and De Ranee to the west of
Coniston Lake, we do not find different members of the Upper
Slates abutting against the " lag " fault in so marked a manner as
in the case of the northern fault. Nevertheless, detailed study of
the phenomena has convinced us that we are here dealing with
a true case of faulting, and not with an unconformable junction.

In some places the two " lag " faults come together, and the
Coniston Limestone then rests upon the Skiddaw Slates, as seen
in one or two places in the neighbourhood of Dalton-in-Fumess.

Of the minor " lags," the most interesting to us at present is
that which occurs beneath the Coniston Grits, for it is this which
gives one a clue as to the nature of some of the most striking
" tear " faults. These " tear " faults we may now consider.

(c) The " tear " faults, — If a yielding mass of strata is inter-
calated between two more rigid masses, and separated from them
by lag-faults, portions of it, owing to differential movement, may
have their planes of stratification inclined at a higher angle than
that of the fault-planes. If a fracture takes place parallel or
nearly parallel to the direction of dip of the strata, and move-
ment of the yielding strata occurs at a different rate on either
side of this fracture, any particular stratum will suffer lateral
displacement, which will be readily detected in the case of an
anticline or syncline, but which will present appearances similar
to those accompanying vertical displacement along a normal
fault in the case of strata dipping uniformly in one direction.
That such movement has occurred in our district is shown by the
nature of the displacement of a syncline in the Kirkby Moor
Flags north of Whiteside Pike, between Long Sleddale and
Bannisdale. A little consideration will show that the three great
faults which affect the Coniston Limestone in Troutbeck, to the
west of Windermere, and at the head of Coniston are of this nature.
The displacement of the Coniston Limestone, which is inclined at a

Proc. Geol. Assoc, Vol. XVI, Part 9, AuoirsT, 1900,] 3S

466

MARit OX THE

fairly high angle to the south, is tctj noDoeabk. In the case of
the fault west of Windermere the hteial dispianrmmt as ooeasuxtd
upon the ground is about a mile, and yet the lofver sarbtcc of the
Coniston Grits, only half a mile south of the outcrop of limestone
to the west of the fault, is imdistiiibed by it. This is inoocKeiT-
able upon the supposition that the iuilt is nonnal. but is fully
explicable on the view that the fault is a "tear,"' and suddenly
ceases upward where the "^ lag ** occurs at the base of the Conistoa
Grits. It follows, of course, that whereas the width of outcrop of

Fi^-;^ r— Ma: 07 Ovtckof ot Vol can:: Ro:k>, Coniston
L:>:e570ne, Contston Flac^^, an: Coniston Geits
West ot tee Heai cf W:n: ejlmexh.

z, \\<cs.t/k R.xks. ^ Coniston Grits

r! C.^n;s:or. L:r>cs:.-»ne. LL. Laqj Fault,

t. Cor.:«c^n Kiags ^and St^ckiaic ShaicsX TT. Tear Fault.

the beds lying between Coniston Limestone and Coniston Grits iS
,\K^uT 1 ; miles on the east side of the fault, it is only about i mil^
v^n the west side (see Fig, 2\ Such a change could not he
pnxiDCod by mere compression, and there is no doubt that the
upiv^T ix^n oi the Coniston Flags has been carried away on the
CA« iiidc, and placed elsewhere. If this view as to the nature of
thcM^ on^si tau'ts be nrie, it must frequently happen that masses of
iitrata are missiirw: in i^ome parrs of the district, and reduphcated
c^lj^'where, and ihss js shown to be the case as the result of

GEOLOGY OF THE ENGLISH LAKE DISTRICT. 467

observation. The Falcon Crag group is apparently removed
above the lag fault on the north side of the Green Slates and
Porphyries, both in the Helvellyn range and to the west of
Borrodale, and the line where the disappearance occurs seems
in each case to be a " tear " fault, in one case occupying the
Vale of St. John, in the other Borrodale.

The lower division of the Stockdale Shales is frequently
removed in such a way that the upper division comes against
the Coniston Limestone, but reduplication of these beds occurs
extensively to the south-west of Coniston Lake. Again the
comparatively yielding Bannisdale Slates, between the more rigid
Coniston Grits below and Kirkby Moor Flags above, are fre-
quently reduplicated in the county to the east of Windermere.

In the case of the ** tears " which affect the Coniston Lime-
stone between Kentmere and Coniston, it is noticeable that they
cut through the lag-fault at the base of the Coniston Limestone,
and are accordingly subsequent to it. Their upper limit is
that of the lag-fault at the base of the Coniston Grit, as already
stated. Their lower limit is not so clear, but probably coincides
generally with a lag-fault along the great slate-band running
from Mosedale to Coniston.

It need hardly be stated that the above structure is complicated
by the occurrence of numerous minor lags and tears ; attention
has been called to some of the more striking in order to show
the general nature of the movements which have affected the
rocks.

(d) If this be the correct interpretation of the structure of the
district, it follows that the volcanic rocks, which lagged behind the
Skiddaws, must have accumulated in forc3 to the southward, and
that considerable duplication of volcanic rocks occurred in the
centre of the district. This is fully borne out by the study of
the banded ashes in the centre of the district. They appear
enormously thick when compared with the equivalent beds in the
slate-band to the south, but study in the field shows that there was
great piling up of the ashes in the Scawfell region. The major
divisional planes when viewed from a distance are seen to be at
very low angles, and form a syncline whose centre lies between
Bowfell and Scawfell Pike. When regarded more closely the
minor divisional planes are seen to run obliquely to these larger
planes, and, as will be described more fully in the sequel, still
smaller planes run obliquely to those of intermediate size. In
fact we are dealing with a case of pseudostromatism on a large
scale. The volcanic rocks also seem to have been collected from
east and west to form a huge node-like mass in what is now the
centre of the district, hence the small thickness of these volcanic
rocks in the Cross Fell inlier, and in the neighbourhood of Millom.

The same thing occurred with the Upper Slates, but as these
are more yielding rocks resting on less yielding, instead of less

468

J. E. MARR ON THE

yielding on more yielding, which is the case with the Volcanics
resting on Skiddaws, the great lag-plane was bent sharply downward^

with a dip to the
south owing to the
existence of the but-
tress of unyielding
rock to the north.
Here again, the rocks
seem to have been
collected from east
and west also.

The general
structure which the
Lower Palseozoic
Rocks of the district
would possess, in
accordance with the
above views, is repre-
sented in Fig. 3.

(iv ) Minor Changes

in the Rocks, which are

due to Movement.

As might natu-
rally be expected, the
rocks have been sub-
jected to such
changes as are the
result of compres-
sion in places and
stretching in others.
Before considering
in detai 1 the
changes which have
occurred in the
rocks of each divi-
sion, attention may
be called to the exist-
ence of slaty cleav-
age in all the rocks
which are capable of
exhibiting it, from
Skiddaw Slates to
Ludlow. The Lower
Coniston Flags are
extremely well
cleaved, and the Bannisdale Slates are sufficiently so to be worked
locally for slates. There seems little doubt, from this and other

tA>'^^?

GEOLOCY or THE 09GII5H UULE ]>I5T1UCT. 469

suucmres preseoted bf d^ Upper S2ucs. diat d^ mofgiem mas
not meiely poa-Oi<kw'kaan bot xlso poss-SOmiuv and duo, in Mt,
it occmred daring Denxuin times.

We haw DOC dei^oced pay mncii axtentioD to the chia^ges
which have oocmred in the Skiddav Slites. Bejtxid Jibonduit
signs of minor pockerii^ ve gel evidence of extensive suetchii^
as indicated by the abundance of quanz-rans whidi hai« filled
fissures in many pboes. Sbckcnsiding is frequent, and is often
seen parallel widi the beddii^ and nmning honioncallj along
joint-planes : this is wdl cshibited in the neighbourhood of Scale
Force, Buttermeie. Imitatioo of ripf^marldi^ and ev^n of
organisms, is often pcodooed by pockering and pinching of thin
grit-bands between aigiUaceons strata. A consideiable amount
of chemical change has probably occurred, as the result of mo¥>e-
ment, including & frequent production of seridtic films along
the divisional planes.

It is among the Green Slates and Porphyries that we find the
most interesting minor structures due to earth-movement, some of
which may be briefly noticed.

In the first pla^ when yidding vesicular lavas and ashes
occur in close proximity, the ashes are often involved with the
lavas in a most perplexing manner. Occasionally definite folds
may be detected, but often the ashes occur among the lavas
in the form of curved and curled wisps. We believe that it is
owing to this occurrence that some previous observers have been
led to refer to many of the vesicular lavas as ashes. An
admirable instance of this complexity may be seen on the road*
side in Borrodale, a short distance to the north of the Rosthwaite
alluvial flat, while equally good cases occur among the Troutbeck
slate quarries and by the side of Church Beck, Coniston — to
mention a few out of many.

Reference has already been made to the difficulty of dis-
tinguishing original explosion breccias from those due to sub-
sequent movement. That a great proportion of the breccias in
the district are original explosion breccias may be regarded as
certain, and others may he caused by the breaking up of the
cooled surfaces of lava flows, and incorporation of the fragments
in the still fluid mass. There is no doubt, however, that many
are due to subsequent movement, and some of the evidence for
this statement must now be given.

Many of the breccias occur in bands where there is other
evidence of the existence of lag-planes, and a number of these
are stained purple. Among these is the great breccia at the l)Ase
of the Falcon Crag series, whose cataclastic origin we strongly
suspect though the proofs are at present not convincing.

On High White Stones is a breccia containing fragments of
flinty ash embedded in a finer matrix. The fragments exactly
resemble the Scawfell flinty ashes, and as there is no doubt that

470 J. E. MARR ON THE

the production of the flinty structure occurred after their for-
mation, it is improbable that original breccias should have their
fragments of this character. f.

Far more convincing, however, are the numerous cases, among
the flinty ashes, where every gradation can be traced from folding
to brecciation, or from dislocation of fragments along dominant
joints to brecciation. These may be studied everywhere among
the ashes of the Scawfell group, and I hope to be able to show
the members of the Association excellent examples on the slope
between Sty Head and Sprinkling Tarns.

In several cases the brecciation has gone a stage further, and
cataclastic conglomerates have been formed. They are best
developed among rocks where the brecciation is due to dislocation
along dominant joints. Every gradation may be traced, from
ordinary rock with cuboidal joints, through brecciated rock, to a
rock in which the angles are being gradually worn away, and
finally into a rock where the fragments are completely rounded.
I am not aware of any good cases of this in the immediate
neighbourhood of Keswick, and the most striking case we have
found occurs in a garnetiferous rock on the fell between Hawes-
water and Swindale.

Occasionally the cleavage planes are bent into sharp zigzags,
as shown in some of the porphyritic lavas in the county at the
foot of Haweswater.

When objects of diflerent consistency to the matrix are
found they are frequently crushed nearly flat, and this crushing
is probably accompanied in all cases by a certain amount of
chemical change. In the rocks just alluded to, near the foot of
Haweswater, the cleavage planes are covered with micaceous or
chloritic films, the porphyritic felspars are crushed flat, and
have no doubt undergone chemical change in addition. The
amygdules of the amygdaloidal lavas are often crushed in the
same way, and sometimes curved or even contorted after crush-
ing. This may be seen in the rocks of the section near the foot
of the Rosthwaite alluvial plain. The garnets of many of the
less resisting rocks break across, whereas in firmer rocks they may
be extracted entire. In several rocks the garnets are converted
into chlorite, and sometimes into white mica, though we are not
able to assert definitely that this is a dynamo-metamorphic
change. Even large fragments of breccia are flattened in the
same way as the felspars, as shown in the more intensely squeezed
breccias of Quay Foot Quarry, in Borrodale, where every grada-
tion may be traced. Here again chloritic films are developed
along the surfaces of the fragments.

We have notes of many other minor changes which have
been produced as the result of earth movement in these volcanic
rocks, but the samples given will serve to show the intensity of
the forces which have affected these rocks, though we may

GEOLOGY OF THE ENGLISH LAKE DISTRICT. 47 1

mention that the Armboth dyke has been affected by tear-faults,
and that we have discovered a narrow dyke near Walney Scar
which has been profoundly contorted.

Many of the features we have noticed, and others also, may
be studied among the laminated grits and mudstones which
form the Bannisdale Slates around Windermere, and afford
additional evidence that the movements which produced them
were of post* Ludlow age.

D.— THE LATER ROCKS.

Little will be seen of the later rocks by those who take part in
the excursion, and only a few words are required concerning
them.

At the base of the Carboniferous rocks is the well-known
conglomerate, which is well developed around Shap, and at the
foot of UUs water. It seems to have been deposited in hollows in
the older rocks, probably in old valleys. It used to be referred to
the Old Red Sandstone, but is now usually included among the
Carboniferous strata. I doubt the necessity for the change. In
the Cross Fell inlier very low beds of the Carboniferous series are
undoubtedly developed, and a quartz-conglomerate at the base of
these rests on the polygenetic conglomerate to which we are
alluding. I think it probable that a considerable change took
place between the formation of the two conglomerates, and that
the conglomerate with quartz pebbles forms the true base of the
Carboniferous, while the red polygenetic conglomerate is of Old
Red Sandstone age.

The character of the pebbles is of interest, as was noted by
Otley. In the first edition of his Guide Book, published in 1823,
he refers to the conglomerate. In the second edition (1825) he
adds that the pebbles " must have been transported from some
distance, as the majority do not correspond with those of the
immediate neighbourhood." In the sixth edition (1837) this
statement is expanded, and he remarks that they " must have been
transported from some distance, apparently from the greywacke
division [/>. the Upper Slates], lying at some distance to the
southward." The fact is that many of the pebbles are of Silurian
age, and in the Cross Fell inlier, fossils (probably of Ludlow age)
have been found in them, though I believe that the pebbles came
from the north, for Prof. Hughes has detected fragments of
Keisley limestone in these conglomerates, in the Sedbergh district.
These conglomerates may be seen at the foot of U lis water.

The Carboniferous rocks, as well known, form a broken ring
round the district. The limestones may be seen from the train
when travelling from Penrith to Keswick, and are here dipping
gently to the east.

472 J. E. MARR ON THE

Permian and Triassic rocks occur in the Eden Valley and on
the west coast of Cumberland, and an outlier of Rhaetic beds has
been discovered to the west of Carlisle.

E.— INTRUSIVE IGNEOUS ROCKS, AND THEIR
METAMORPHIC EFFECTS.

A large number of masses of intrusive rock of considerable size
occur in this district, and are accompanied by many minor dykes,
sills, and laccolitic masses. Very little has been ascertained con-
cerning the ages of most of them, and it will be convenient there-
fore to consider them according to the age of the beds into which
they have been forced, as this order, being purely artificial,
introduces no theoretical considerations.

Skiddaw Granite, — This is the lowest of the extensive masses
of igneous rock, the exposed parts being intrusive in the Skiddaw
Slates. It occurs in three exposures, which are doubtless con-
nected beneath the surface. The generally horizontal surface
suggests a laccolitic character for the intrusion, though the southern
exposure, in Sinen Gill, is probably a tongue from the main mass.
The normal granite " is essentially a biotite granite, consisting of
orthoclase, oligoclase, quartz, and brown mica. ... In addition
to the magnesian mica there are often scattered flakes of
muscovite, which are always subordinate, and not constant
enough to be regarded as an essential constituent." Mr. Harker
has shown that in the northern exposure, where Grainsgill joins
the Caldew Valley, the granite gradually passes into greisen, wkh
felspar subordinate or wanting, and plentiful white mica. He gives
reasons for supposing that this modification is due to the greisen
having been forced northward " from the partially consolidated
Skiddaw granite." This is suggestive as possibly throwing some
light on the age of the intrusion. We have seen that the Devonian
movement which produced the great changes in the Lower
Palaeozoic rocks of the district was from south to north, and it
seems probable that this granite was injected into the rocks during
the occurrence of these movements, in which case the rock would
be of Devonian age.

I hope that the members or the Association may be able to
view the upper junction of the normal granite with the Skiddaw
Slates at Sinen Gill ; it will be then seen that the sedimentary
rocks were cleaved before the intrusion of the granite, which
would suggest a late age in the period of movement for the period
of intrusion.

Evidence will be given that some of the other laccolitic intru-
sions have been forced along lag-planes. It is possible that the
Skiddaw granite was forced along the great thrust-plane which we
have discussed, It is not far distant from the outcrop of the

GEOLOGY OF THE ENGLISH LAKE DISTRICT. 473

Drygill shales, which, as before observed, may be situated below
the thrust.

The metamorphism of the Skiddaw Slates by the Skiddaw
granite has been described by Mr. Clifton Ward in the Survey
Memoir, and by Prof. Rosenbusch in "Die Stiegerschiefer."
An outer zone of chiastolite slate passes into a central one,
where the rock is marked by an abundance of spots com-
posed of andalusite mixed with flakes of mica ; close to the granite
this spotted rock passes into a mica-schist. These changes may
be studied in the Glenderaterra valley on the way to Sinen Gill.

The changes produced by the granite have only been gener-
ally studied, and detailed examination of the slates will probably
result in the detection of numerous minor variations in the
character of the metamorphism. Mr. Harker has recorded the
occurrence of cordierite m the Skiddaw Slates of the Caldew
Valley, south-west of the farm of Swineside.

Carrock Fell Intrusive Rocks, — The rocks of Carrock Fell and
the surrounding tract of country form an igneous cpmplex, which
has been very fully described by Mr. Harker. The rocks in their
order of consolidation are (i) Gabbro, (ii) Granophyre, (iii)
Diabase, (iv) certain basic and sub-basic dykes and veins, often
variolitic. All of these rocks are probably of the same general geo-
logical age, and may be the result of differentiation of one magma.
The gabbro has itself undergone a process of differentiation, for
quartz gabbro occurs in the centre of the mass, while on either
side of this is a normal rock, composed of triclinic felspar and
monoclinic pyroxene, and, on the outer margins, these two
minerals aie associated with abundance of iron-ores.

The granophyre consists of a granophyric intergrowth of
quartz and felspar, and of augite crystals. The granoph)Tic
structure varies considerably in different parts of the rock. As
the granophyre was consolidated subsequently to the gabbro, it is
found that dykes and veins of the former penetrate the latter. A
remarkable modification at the junction is explicable on the view
that the granophyre melted the original margin of the gabbro,
and as a result a narrow l^and of very coarsely crystallme rock
separates the gabbro from the granophyre in places. It is well
shown in Farthergill Sike, above Stone Ends Farm, and it is to
l)e noticed that the most basic modification of the gabbro has
been thus affected by the acid rock.

The diabase and the basic dykes do not call for special notice
in this place, and the metamorphic effects of the igneous rocks,
though not traceable to a great distance from those rocks, are of
too intricate a character to discuss here ; suffice it to state that
when the gabbro has broken into rocks of the Eycott volcanic
series, not only are the latter altered, but they have caused
marginal modifications in the composition of the gabbro.

The Carrock Fell rocks appear to be faulted to the north and

472 J. E. MARR ON THE

Permian and Triassic rocks occur in the Eden Valley and on
the west coast of Cumberland, and an outlier of Rhaetic beds has
been discovered to the west of Carlisle.

K— INTRUSIVE IGNEOUS ROCKS, AND THEIR
METAMORPHIC EFFECTS.

GEOLOGY OF THE ENGLISH LAKE DISTRICT. 473

Drygill shales, which, as before observed, may be situated below
the thrust.

The changes produced by the granite have only been gener-
ally studied, and detailed examination of the slates will probably
result in the detection of numerous minor variations in the
character of the metamorphism. Mr. Harker has recorded the
occurrence of cordierite in the Skiddaw Slates of the Caldew
Valley, south-west of the farm of Swineside.

The granophyre consists of a granophyric intergrowth of
quartz and felspar, and of augite crystals. The granophyric
structure varies considerably in different parts of the rock. As
the granophyre was consolidated subsequently to the gabbro, it is
found that dykes and veins of the former penetrate the latter. A
remarkable modification at the junction is explicable on the view
that the granophyre melted the original margin of the gabbro,
and as a result a narrow band of very coarsely crystalline rock
separates the gabbro from the granophyre in places. It is well
shown in Farthergill Sike, above Stone Ends Farm, and it is to
be noticed that the most basic modification of the gabbro has
been thus affected by the acid rock.

The Carrock Fell rocks appear to be faulted to the north and

474 J. E. MARR ON THE

south, and as there are no exposures at the east end, and
indifferent ones at the west end, the nature of the intrusions
is doubtful. The manner in which the Eycott rocks are pene-
trated by the igneous rocks, and have furthermore been buoyed
up by them, suggests, however, that we are here also dealing with
a laccolitic mass, and as this mass is in close proximity to
the Drygill beds, the suggestion made in the case of the Skiddaw
granite is applicable here also.

The age of the rock cannot be definitely fixed, but there are
certain points in the petrographical structures of the rocks, and in
the physical structure of the surrounding district, which suggest a
more modern date than that which was tentatively assigned to the
Skiddaw granite.

The Microgranite of the Vale of SL John, — This rock occurs
in two patches, one on either side of the Vale of St. John, with
Skiddaw Slates between them. They have been forced along the
lag-plane separating the Skiddaw Slates from the Green Slates and
Porphyries. They were almost certainly once continuous, the
intervening portion having been removed by denudation, and
appear to form parts of a laccolitic mass, dipping gently to
the north, />., in the direction of the fault-plane. The grey
compact "ground-mass consists of a finely granular aggregate of
quartz and felspar, the latter predominating." Flakes of biotite
are present, and small porphyritic crystals of plagioclase felspar.
The rock has suffered decomposition to some extent.

Granophyre of Buttermere and Ennerdak. — The rock consists
of a granophyric intergrowth of quartz, orthoclase and plagioclase
felspars. The ferro-magnesian constituent is usually altered into
a chloritic mineral, and epidote is also very abundant in many
parts of the rock.

This and the Eskdale granite occupy a much greater superficial
area than any other intrusive rocks in the district, the length of the
exposure of Ennerdale granophyre being about nine miles from
north to south ; this is slightly exceeded by the Eskdale granite,
which occupies a distance of about ten miles from north to south (or
of fourteen miles, if the patch at the head of Wastwater is connected
at the surface with that at the foot.)

The Ennerdale granophyre is evidently a laccolitic mass which
has been on the whole forced along the lag-plane l)etween the
Skiddaw Slates and the volcanic rocks, though portions of it occur
in the Skiddaw Slates, and other portions are apparently situated
entirely in the volcanic beds.

There are two laccolitic masses, connected by a dyke-like
band which is seen on Little Dodd, about two miles west of
Buttermere lake. The lower mass of the laccolite, is about three
miles long, and extends from Gale Fell to the shores of Butter-
mere, an isolated patch being also developed a little farther to the
south on the south-west shore of the lake. The junction with the

GEOLOGY OF THE ENGLISH LAKE DISTRICT. 475

Skiddaw Slates below may be seen in many places in the neigh-
bourhood of Scale Force, and it is clearly seen to follow the bedding-
planes of the strata. A number of tongues of the granophyre
project into the Skiddaw Slate at the lower surface, and form
subsidiary sills. The upper margin of the lower mass of the
laccolite is also pierced by Skiddaw Slates, except at one spot,
close to the summit of Red Pike, where it is in contact with the
volcanic rocks. The width of this portion is about a mile in the
widest part. Though it runs nearly from east to west, it is seen in
the field to be sloping towards the S.E., as its eastern extremity
is at a much lower level than the western. The remaining part
of the laccolite is of much greater size. The lower surface
extends from Floutern Tarn to the neighbourhood of Ennerdale
Lake, and rests on the Skiddaw Slates, while the upper surface
is capped by the volcanic rocks which form the hills between
Buttermere and Wastwater. It is interrupted by two bands of
volcanic rock north of Kidbeck, near the foot of Wastwater, where
denudation has not been sufficient to lay bare the upper surface of
the igneous rock.

The existence of more basic patches in the main rock, and of
dykes and sills of a more acid or more basic composition in its
neighbourhood, suggests the former existence of a magma which
underwent differentiation in a manner somewhat similar to that
which has been described in the case of the Shap granite. Some
of these are well shown below Burtness Comb, Buttermere. The
task of connecting the minor intrusions with the Ennerdale
granophyre and Eskdale granite respectively will probably be
one of considerable difficulty, as the two rocks come into contact
with one another at the foot of Wastwater.

The metamorphism produced by the Ennerdale granophyre is
pretty considerable, though no detailed study has been made of
its effects, (iood examples of the metamorphism undergone by
the Skiddaw Slates may be obtained in the vicinity of Scale
Force.

The Eskdale Granite, — This rock extends from the foot of
Wastwater to the northern flanks of Black Combe. It consists of
red felspar, quartz, and dark mica. The felspars are both oitho-
clase and plagioclase, and the triclinic potash-felspar microcline
also occurs.

The rock is clearly a laccolitic intrusion, as shown by the
manner in which tongues extend up the valleys, e.g.^ at Wastwater
and up Miterdale and Eskdale, and by the existence of a small
isolated patch of volcanic rock on its upper surface, near Boot, on
a hill called Great Barrow. It is probable that the junction with
the volcanic rocks is in all cases that of the upper surface of the
laccolite, and we may suspect from its position that the rock was
forced along the same plane as that which determined the lines of
intrusion of the Ennerdale and St. John's rocks.

47^ J- E. MARK ON THE

The metamorphism by this granite, so far as it has been
studied, appears to be of very much the same type as that which
has been described in connection with the granite of Shap.

Garnet-bearing Rocks below the Banded Ashes of ScawfelL — I
have left until now the consideration of a very remarkable group
of rocks which is very widely spread among the Green Slates and
Porphyries of the district, but which nowhere attains so great
importance as just below the great series of banded ashes which
form the upper portions of Scawfell and its satellites. I have
already had to notice the occurrence of well-formed garnet-
crystals in the undoubted lavas of the Falcon Crag series, and
they are also present in undoubted intrusive rocks, for instance, in
the well-known Armboth dyke. They also occur in ashes and
breccias, though how far the latter are explosive breccias is as yet
doubtful, but their presence in true ash (<r.^., that between Ward's
lavas Nos. i and 2 on Falcon Crag) is indubitable. Two inter-
esting questions arise concerning the rocks we are at present con-
sidering, viz., whether the rocks are contemporaneous lavas or
intrusive igneous rocks, and whether the garnets are original or
secondary. It is known that original garnets occur in igneous
rocks, as, for instance, at Nathrop, in the Colorado district, with
which some of our rocks present certain resemblances. The
evidence on this point is at present indecisive, and I can only
record my opinion, formed after considerable study of the rocks
in the field, that the garnets of the Lake District igneous rocks
are also original.

The normal rock is greyish or greenish, with a compact base
in which are situated fairly large porphyritic felspars and often
augites. The garnets vary in quantity, being sometimes sparsely
distributed, at other times very thickly, as on Gunson Knotts,
Crinkle Crags, and lUgill Head, Wastwater. In some places a
nodular rock is found, as at the summit of Kidsty Pike, near
Haweswater. It may be noticed that similar nodules occur in
places in the Armboth dyke.

When the rock is cleaved very marked changes may occur
in it. The garnets become replaced by chlorite, or mica, as
before stated, and a number of secondary minerals may be
developed in the rock itself. Sometimes the cleavage planes are
bent in abrupt zigzags. These changes may be seen in dykes on
the hillside east of Watendlath Tarn.

The rock is often brecciated, though, as observed before, the
origin of these breccias is doubtful.

A peculiar and very interesting type of the rock is somewhat
widely distributed. We have been accustomed to speak of it as
the " streaky " type — a sufficiently expressive term, though the
streaks may not always originate in the same way. Sometimes
lenticular linear streaks of a darker colour are found in the
rock. At others, long ribbon-like patches are seen, and

GEOLOGY OF THE ENGLISH LAKE DISTRICT. 477

occasionally these are found to flow round eyes of rock, which
bear a resemblance to fragments of lava. In some cases the
streaks are probably patches of rocks of different appearance to
the main mass, which have been flattened out as the result of
pressure applied after the consolidation of the rock. At other
times the structure is so remarkably like the flow structure of an
igneous rock, that one can hardly avoid the conclusion that it was
impressed on the rock prior to its consolidation. Excellent
examples of this type of rock occur on the path from Stockley
Bridge to Sty Head Tarn, while many varieties of the " streaky "
rock are found in the Langstrath valley. The rocks will be
studied in each of these localities.

A description of these rocks may be concluded with a few
remarks bearing upon their origin.

A minor sill, of quite normal appearance, is visible on the
path from Stonethwaite to Dock Tarn. At the upper surface the
garnet rock is seen to send veins into the overlying banded ashes,
and fragments of the latter are included in the garnet rock.
Furthermore, the ash appears to have been altered at the contact,
for a band of spotted rock is found at a distance of about an
inch from the actual contact. Immediately above these ashes,
and on the south side of the footpath, is another garnet-bearing
rock, which is probably a lava.

At Blea Crag, in the Langstrath valley, is a complex of
igneous rocks, the relationship of which has not yet been fully
worked out. Some, if not all, of these rocks contain garnets,
and the whole mass is clearly intrusive. This is one of the
many laccolitic masses, which have been mapped as intrusive,
which contain garnets.

Again, garnet-bearing dykes become very abundant in the
neighbourhood of the main mass of garnet rock. These dykes,
as well as the sills and laccolitic masses, have frequently under-
gone great change as the result of pressure, which suggests that
they were all formed at a time prior to that of most of the other
intrusive igneous rocks of the district.

The flinty type of ash is mainly found where the Scawfell
ashes lie above the garnet-rock. The latter is specially developed
in the High Street range and in the Scawfell district, and there
the flinty ashes predominate. Again, the garnet-rock is found
somewhat low down on the flanks of Helvellyn, and accordingly
the flinty type of ash is seen near the base, at no great height
above the garnet-rock, while the ashes near the summit do not
show this type of alteration. These facts suggest the production
of flinty texture, as the result of metamorphism by the garnet rock.

I am inclined to think, therefore, that the evidence, on the
whole, points to the intrusive character of the great bulk of these
garnet rocks, though it is very desirable that more evidence
should be gathered.

478 J. E. MARR ON THE

The Shap Granite is the only other important igneous rock of
considerable extent which is found in the district. As it lies away
from the area to be visited by the Association, I need not give a
description of it. The rock itself is sufficiently well known.

In addition to the large masses there are some smaller ones,
which merit notice. Professor Bonney has described a homblende-
picrite from Little Knott. The well-known rock of Castle Head,
Keswick, has received attention, as Mr. Ward suggested that it
might mark the vent of one of the Lake District volcanoes, a
suggestion which is confronted with some difficulties. The rock
is very rotten, and of little interest. It is a dolerite or diabase.
Lastly, there is the sill connected with the plumbago mine, which
Mr. Ward describes as " highly altered diorite lying between two
other masses of intrusive blue trap (diabase) of a compact
character."

Countless dykes and minor sills and laccolites are scattered
through the district, but apart from knowledge of the main masses
with which they are connected, their description would be of very
little interest.

In concluding this account of the rocks of the district, I would
point out that in this area, where there is evidence of profound
earth-movements affecting rocks, many of which from their com-
position are peculiarly adapted to undergo chemical changes, it is
only around the masses of igneous rock that we meet with rocks
comparable in composition and characters with those which are
characteristic of an area of " cr}»stalline schists."

F.— GLACIAL AND POSTGLACIAL DEPOSITS, ETC.

The accumulations of till, with their associated stratified sands
and gravels, which occupy the low ground surrounding the
district, extend up some of the valleys, and occasionally occupy
high ground, as on Matterdale Common. Towards the head of
the district they are usually absent, and their place is taken by
local glacial accumulations, which rarely occupy very extensive
tracts of country, thus allowing the solid rocks to appear at the
surface with great frequency. In the immediate vicinity of
Keswick, till is found associated with stratified gravels, and the
drift mounds which occur around the town, and project from the
alluvial flat between Derwentwater and Bassenthwaite, are formed
of this lowland drift.

The glacial phenomena in the interior of the district have been
very fully described by Mr. Clifton Ward, and it is only necessary
to allude to some of the features which the members of the
Association will have an opportunity of observing during the
forthcoming excursion.

Striated rocks and roches moutonnees are abundant. Good

GEOLOGY OF THE ENGLISH LAKE DISTRICT. 479

examples may be seen in Borrodale, one of the most striking
being that formed of Skiddaw Slate, on which Grange Bridge is
built Immediately opposite is a vertical cliff of volcanic rocks,
which is smoothed and striated. At Sprinkling Tarn it will be
noticed that the escarpments of flinty ash have merely had their
edges modified by ice-action.

Moraines are abundant, especially in the upland valleys.
Lateral moraines are not very readily detected, as the depression
which once existed between the hillside and the moraine has
usually been tilled up subsequently with screes and rain-wash.
A well-marked lateral moraine will be noticed at the foot of
Greenup Gill.

Several interesting moraines occur near Rosthwaite. The
lowest is seen standing upon striated rock at the foot of the
great alluvial flat. The next starts from the end of the ridge
separating the Stonethwaite and Seathwaite valleys, and runs
round to Rosthwaite, being plastered against the south side of
the rocks under which part of the hamlet nestles. A well-marked
moraine occurs at the lower end of the Seathwaite valley just
above Seatoller.

In the Stonethwaite valley they are abundant. One occurs
at the bottom of the valley, and a number of others may be
traced up the Langstrath valley, each having given rise to a tarn,
now replaced by alluvium, and having also diverted the drainage.
The most striking case has been figured in the GeograpJdcal
Journal^ but it will be noticed that at the foot of each alluvial
flat is a rocky gorge, with moraine-material on one side of it.

Many moraine mounds will be seen near Stockley Bridge, and
also at the head of the valley which descends from Honister Pass
to Seatoller.

Mr. Ward has referred to the comparative rarity of perched
blocks. They are tolerably abundant on the plateau by Sprinkling
Tarn. The visitors will have ample opportunity of noticing other
boulders, especially those of volcanic material resting on the
Skiddaw Slate, showing the general northerly movement of the ice
about Keswick. The well-known Bowder Stone is not a boulder,
but a mass of rock which has fallen from the cliffs above, probably
down a snow-slope. Such falls must be frequent, and the writer
found evidence of a very considerable one which must have
occurred at the end of the present winter from the combe on
Gale Fell, at the head of Mosedale, near Crummock.

The post-glacial accumulations consist of soil, screes, rain-
wash, peat on mountain slopes and elsewhere, river-alluvia, and
lacustrine deposits. Of these it is only necessary to notice the
last mentioned accumulations.

The present lakes are gradually being filled up with mechani-
cal detritus, shell-marl, and diatomaceous deposits, while peat
usually forms the surface-accumulation after the lake has been

480 J. E. MARK ON THE

converted into marsh. The deposition of material must have
been fairly continuous since the lakes were formed, and accord-
ingly most of the smaller ones have already been filled up and
converted into alluvial flats. Occasional sections are exposed,
and exhibit the nature of the deposits. Shell-marl occurs at the
base of a peat-bog around a small tarn termed Haweswater, near
Silverdale, on the southern edge of the district. Mr. Strahan has
recorded diatomaceous earth among the deposits of the former
Kentmere Tarn, which has been artificially drained, and Mr. J.
Bolton detected a diatomaceous earth surmounted by nearly 100
feet of other deposits at Lindale Cotes, near Ulverston. Clay
with vegetable remains is fairly abundant. This clay is some-
times contorted and contains small boulders ; when in this state
it was probably deposited before glacial conditions had altogether
disappeared from the district.

G. — OBSERVATIONS ON THE PHYSIOGRAPHY OF
THE DISTRICT.

The radial arrangement of the main drainage lines from a
point about Scawfell has been frequently noticed and discussed.
Subsequently to the initiation of these main lines of river-
drainage, secondary changes have occurred, and complicated,
without in any way masking, the original drainage. Some of the
secondary changes were due to ordinary events in the history of
a land area, while others have been caused by glacial interference.
The members of the Association who visit Lakeland will have
opportunities of studying minor examples of each of these.

The rivers in the lower parts of the valleys have in most
cases established their base-lines of erosion, being no doubt aided
therein, in the case of those valleys occupied by lakes, by the
raising of the water level at the lake-heads. In upland regions
the base-lines have not yet been fully established in every case,
and, accordingly, while the mountain-slopes present the curves of
stream-erosion, they are often complicated by the existence of
minor precipices and steep slopes. This is naturally seen more
frequently among the very variable rocks of the volcanic series
than among the softer and more uniform rocks of the Skiddaw
Slates, and, accordingly, the curve in the latter is often unbroken,
while in the former it is interrupted by alternating gentle and
steep slopes.

The upper parts of many of the hills are frequently occupied
by vegetation, and there the curve of stream erosion is replaced
by a convex curve of weathering. This is specially seen on the
slopes which face westward and southward, while on the north
and east sides the curve of stream-erosion may be frequently
traced to the summit of the mountain. There are exceptions to

GEOLOGY OF THE ENGLISH LAKE DISTRICT. 48 1

this, as when the valley on the south or west is at a much lower
level than that on the north or east One very striking example
is Saddleback. On the south side of this hill the regularity of
river-valleys which have been initiated in rocks of uniform
composition, when other conditions are also uniform, may be
well studied from the railway between Troutbeck and Threlkeld
stations. A series of buttresses, at fairly regular distances apart,
separate deep combes hollowed out of the mountain side.

Upland valleys often end suddenly against the mountain side,
and the stream from them flows in cascades down the side of the
main valley, without cutting out any appreciable depression.
Many of these are seen on the east side of Helvellyn, and one or
two in the Langstrath valley. The Watendlath valley terminating
in Lowdore waterfall is a very striking case. The explanation
of the occurrence need not necessarily be the same in each case.

Many of the waterfalls in the district are due to glacial
interference, for instance the small one at the foot of one of the
alluvial flats, to which reference has already been made. Others
as obviously are not connected with such interference. One of
the most noteworthy of these is Scale Force, near Crummock,
which owes its existence to the juxtaposition of soft Skiddaw
Slate and hard granophyre. It is probably of no great antiquity,
as the fall has not receded very far, and it is probably post-glacisd.

In the higher parts of the district many remarkable gorges,
similar to the roflas of Switzerland, are seen. They are usually
excavated along dykes, faults, or mineral veins. Of these, Peers
Gill, which may be seen from the top of Sty Head Pass, is
one of the most remarkable. Similar roflas possibly existed in
the lower parts of the district, but have been filled with glacial
accumulations.

The influence of the dominant planes of weakness in the
rocks upon the superficial features may be admirably seen about
Sty Head and Sprinkling Tarns. Peers Gill has a Z-shaped
course, determined by two sets of planes at right angles to one
another. The east side of Sprinkling Tarn and the correspond-
ing side of the fairy-like High House Tarn are determined by
one plane, and the courses of the gills in the neighbourhood
were clearly determined by similar planes.

I have touched on a few points only in connection with the
scenery of the district and its dependence ujKjn the geology.
Many others will doubtless be detected and discussed by the
members of the Association who visit the district, and we may
reserve their consideration until they can be regarded on the
spot.

The fossils of the Keswick district are few and far between ;
the problems coimected with the rocks in many cases obscure ;
but I know of no fairer field for the study of physiography, and I
have tried to plan the excursions in such a way that study of the

Pkoc. Geol. Asioc., Vol. XVI, Part 9, Ar/o'sT, 1900.] 36

484

ZONAL FEATURES OF THE CHALK PITS

IN THE ROCHESTER, GRAVESEND,

AND CROYDON AREAS.

By G. E. DIBLEY, F.G.S.
{Read A^il 6th, tgoo )

THE object of this paper is to describe the chalk pits in the
Rochester, Gravesend, and Croydon areas, and to provide
a list of the organic remains found therein by the author, in order
to determine the horizons of the Chalk exposed. The localities
of the pits are indicated by the numbers on the accompanying
maps. Each pit is distinguished by a corresponding number in
the text.

I have not found any specimens of Uiniacrinus or oiMarsu fifes
in the course of my six years of diligent collecting, and this seems
to show that there is no chalk in the area under discussion newer
than that of the zone of Micraster cor-anguinum.

The solitary specimen of Actinocamax merceyi from " The
Quarry," Strood, is of interest, as Dr. Rowe's lowest record for
the same species is about 30 ft. below the " Bedwell Line " at
Margate. The occurrence also of Actinocamax verus and of A.
merceyi at Cliffe is highly suggestive of the Marsupites-zow^. Dr.
Rowe's specimen of A, merceyi came from the Uintacrinus-h2Jid
of the Marsupites-zont, and it is therefore possible that some
vestige of that band may yet be found in the Rochester-Gravesend
area.

The fact that collecting in pit sections has almost always to be
done from fresh surfaces makes it exceedingly difficult to find such
small organisms as isolated plates of Uintacri?ius,

ROCHESTER DISTRICT.

Strood.— The large pits, known as " The Quarry" (i), north-
east of Strood Station, are in the Micraster cor-anguinumzone.
The chalk is soft and flints abundant ; it is worked to a depth of
from 50 to 80 feet. The general dip is to the north. The pre-
dominant fossils are Micraster cor-anguinum^ Echinotonus coniatSy
and Echifwcorys vulgaris. Only one specimen of Actinocamax
merceyi has been recorded from these pits, and this has been
presented to the British Museum by Mr. W. H. Ball.

We have here an horizon lower than that of the Gravesend
area, as proved by the dip, and by the fact that forms characteristic
of that district are rare.

Messrs. Martin and Earle's pits (2) are situate to the west of
the old South-Eastern line.

Proc. Geol. Assoc, Vol XVI, Part 9, August, 1900.]

G. E. DIBLEY ON ZONAL FEATURES OF THE CHALK PITS. 485

Maps of the Gravesend and Rochester Areas. Reduced from
the Ordnance Survey Maps, sheets 271, 272. Scale, i inch — 2 miles.
(Portion of Sheet 272, showing the position of pit 13, is inserted in the
Gravesend map.)

486 G. E. DIBLEY ON ZONAL FEATURES OF THE CHALK PITS

The chalk is characterised by many layers of flint, both
nodular and tabular ; the northerly dip is well seen, and lower
beds are exposed than those met with at " The Quarry." A hard
band occurs at about 20 ft. from the top, which, so far as examined,
contains but few fossils. About 80 to 100 ft. of chalk is exposed
in this pit, and the whole of it is, I believe, in the Micraster
cor-anguinutn and Micraster cortesiudinartum-zones, Micrasier
cor-anguinum is the typical fossil ; Echinoconus conicus has not
yet been recorded. The downward succession, as we collect
southwards, is well shown by the fauna.

Messrs. Booth and Co.'s pit (3), is about a quarter of a mile
south of the last described pit, and on the western side of the railway.
The cutting leading to the pit shows about 70 ft. of chalk with
the hard band just referred to at the top, and one or two well-
marked bands of flints, then a space of about 30 ft. with few
flints, then from this flintless space downwards three other well-
marked bands occur. Nodular chalk extends to the base.

The Micrasters found here belong to the M, cor-testudinarium
and M, precursor groups, the essential details of the ornament of
the test showing that they belong to a lower horizon than those
from the pits previously described. Holaster planus has not been
recorded, but the Micrasters show that we are in the immediate
neighbourhood of, if not actually in, the Hoiasier planus-zovi^

The Cuxton Pit belonging to Messrs. Weekes and Trechmann
(4) opposite Whorne's Place, was visited by the Association last
year.* Many of the specimens in the British Museum, labelled
** Whorne's Place, Rochester," are from this pit.

From 200 to 300 ft. of chalk are exposed. Well-marked bands
of flint occur near the top, with scattered flints, and one or two
l)ands below, in a hard, nodular and iron-stained chalk. The
lower portion of the pit is in a compact flintless chalk with very
few fossils. The upper part has yielded a rich fauna.

Micrasters of the AT, cor-tesUidlnarium and M. precursor
groups are common, M, hskei is rare, and I have only one
specimen of M. cor-bovisy and one of M, cor-angut'num. Holaster
planus and Terebratulina gracilis are abundant. Pentacrinus
columnars are frequently met with in the Holaster planus-TX^xx^,
Echinoconus subrotundus occurs ; Rhynchonella cuvieri is fairly
abundant. Cyphosoma radiatum is a reliable zone-fossil at this
horizon.

From a study of the Echinoderms it is evident that we have
in this pit probably a capping of M, coranguifium-zont^ the Af,
cor-testudinarium zox\Qy that of Holaster planus^ and of Tere-
bratulina gracilis^ and possibly the upper part of Rhynchonella
aivierizQwt.

Messrs. Formby and Co.'s pit (5) about half a mile south of
the last, shows a section similar to that seen in the pit last described.

• Proceetiini;s, vol. xvi, p 249.

IN THE ROCHESTER, GRAVESEND, AND CROYDON AREAS. 487

By following the tramway from this pit, we enter other large pits
on the right, worked in the zone of Rhynchonella cuvteri. The
bases of the pits evidently are in the Actinocamax p/enus-baind as
can be seen by the dip of this bed in the pits (No. 6).

Messrs. Hilton, Anderson and Co.'s pits (6). — The upper pits
are in the Rhynchonella cuvieri-zont. At about 30 ft. from the base
the Actinocamax p/enus-hand is seen. Discoidea cylindrica has
been obtained recently from this part of the pit. A notable feature
here is the denudation of the Chalk, leaving a valley between the
pits and the Down on the west. The frequent occurrence of gravel
pipes, but rarely to be seen in the pits previously visited, is also
noteworthy.

Messrs. Lee and Co.'s pits at Holborough (7). — The zones of
Rhynchonella aivien\ Actinocamax plenuSy and Holaster subglobosus
are here well seen. This is the last of the large excavations on
the western side of the Medway. It is probable that specimens in
various museums labelled "Snodland" came from these pits.
Hippurites are sometimes found in the Rhynchonella cuviert-zon^
of this area. Discoidea cylindrica is obtained here, though not
previously recorded from the Holaster sufiglodosus-zone on the
eastern side of the Medway.

BURHAM DISTRICT.

" The Free School Pit " (8) has yielded a fine specimen of
Hippurites. Here the zones range from Rhynchonella cuvieri to
Holaster subglobosus.

On the right are large excavations belonging to Messrs.
Peters and Co. (9), extending to Upper Burham. The Actinocamax
plenus zone is distinctly seen, capped by the Rhynchonella cuvieri-
zone, and forms a marked feature from 10 to 20 ft. below the top
of the pit ; the lower portion is in the Holaster subglobosus-zone.

The writer is strongly of opinion that the Chalk is here faulted
and folded, and that the Medway has cut its way through a line
of fault, as the corresponding zones on the west side of the river
are at a much higher elevation. For instance, though the
Actinocamax plenus zone is not reached at Messrs. Weekes and
Trechmann's pits (4), here at Messrs. Peters and Co.'s pits it is
about 80 ft. above the river ; while at Blue-Bell Hill Pits (10) it
is fully 300 ft. above the river.

The Blue-Bell Hill Pits (10), locally known as "The New
Found Out," form a prominent feature in the landscape, being
cut into the North Downs, which here reach nearly 700 ft. O.D.
These pits probably afford one of the finest inland sections of
Chalk in England.

Two pits are seen, the upper and the lower, Holaster subglobosus

488 G. E, DIBLEY ON ZONAL FEATURES OF THE CHALK PITS

and Holaster trecensis are obtained in the lower pit together with
Ammonites rhotomagensis. The Chalk Marl is of a creamy colour,
and easily distinguished from the overlying white beds. The
upper portion of the lower pit contains the Actinocamax pUnus-
zone, and above it occurs a hard band, locally known as " soap,"
containing casts of Inoceramus mytiioides {=iabiaius\ and
forming the division between the lower and the upper pit. In
the upper pit nearly 300 ft. of chalk are exposed, consisting of the
Rhynchonella awieri-zone^ the Terebratuiina graaVis-zone^ and the
Ifo/as/er p/anus'heds. The same features in the chalk are met
with here, 600 ft. above the river, as at Whome's Place, Cuxton,
and Echinoconus subrotundus and Pentacrinus are plentiful.
Owing to the steep angle of the workings in this and in the Cuxton
district, it is difficult to determine the exact limitation of the zones
by personal collection of the fossils. Micrasters are very rare ; I
have found Micraster cor-bovis and Micraster leskei. Vertebrates,
chiefly fishes, occasionally occur. Otherwise the pits have yielded
a rich fauna, as exemplified by the list at end of this paper and
the specimens in the British Museum.

Messrs. Tingey and Co.'s large pit (11) is situated half-a-mile
north of Wouldham. The chalk is worked to a depth of about 80
ft, the base of the pit being about 30 ft. above the river. Echino-
conus subrotundus is faiily abundant. The zones are those of
Terebratuiina gracilis and of Rhynchonella cuvieri.

Borstal Manor Pit (12), owned by Messrs Booth and Co., is
situated about a mile north of that last described. The section
here worked is about 70 ft. The chalk and its fossils correspond
with those of the upper part of the Whorne's Place pit on the western
side of the Medway. Holaster planus^ Terebratuiina gracilis^
Rhynchonella cuvieri, and Pentacrinus are found in this pit; while
on the opposite side of the river, at Messrs. Martin and Earle's pit
(2) and at a slightly lower elevation the first three low -zonal fossils
are not met with. The hard blocky chalk with few flints is seen
in this pit and there is a well marked band of large flints about
20 ft. from the top. The zones are those of Holaster planus and
Terebratuiina gracili:. Three prominent marly bands are seen in
the disused portion of the pit, one just under the flints, one near
the centre, and a third near the base.

Cliffe (13) is about five miles north of Strood. — The chalk
here is worked for about 70 ft., and is of the same lithological and
zoological facies as that in the Gravesend area, being very soft
and friable. It contains decidedly higher zonal forms than those in
the neighbourhood of Strood. The carinated form of Micraster cor-
anguinum^2\^o Echinoconus conicus^ Cyphosoma kOnigiy Actinocamax
verus^ and A, merceyi are common; A, westphalicus has been
obtained. From the association of these fossils we should expect
to find traces of the Afarsupifeszovxt, Information on this point
is desirable.

IN THE ROCHESTER, GRAVESEND, AND CROYDON AREAS. 489

GRAVESEND DISTRICT,

Gravesend, Northfleet, Swanscombe, AND Farningham
Road (numbered 14 — 25). — All the pits in this district are at
about the same horizon, viz., that of Micraster cor-anguinum.
The chalk is very soft, and the flints form prominent bands, both
nodular and tabular.

The fauna includes the carinated form of Micraster cor-
anguinum^ which is abundant, also Echinocorys vulgaris with its
varieties, and Echinoconus conicus. The Echinoconus is typical,
and there is also a well-marked variety somewhat resembling
E. subrotundus of the Rhynchonella cuvieri-zone.

Janira quinquecosiata is but rarely found. Dr. Arthur Rowe
obtained a specimen of Holaster placenta from this area (Tol-
hurst's pit, 15).

A fine specimen of Ammonites of the leptophyllus group has
been recently obtained by Mr. W. Tolhurst, the proprietoi of
one of the pits. It is in the form of a flint cast 18 inches in
diameter, and is the only one known to the writer during six
years' work in this locality, with the exception of an Aptychus and
an Ostrea bearing the impression of ammonitoid sutures. Dr.
Sharpens type specimen of Ammonites leptophyllus is said by him
to have come from this neighbourhood.

By referring to the list appended it will be seen that the
Cidaridae and Asteridae are abundant, as are corals of the
Parasmilia type and also fiourgueticrinus. In the Rochester
area these forms are exceedingly rare in the Chalk, but spines,
plates, and occasionally whole tests of Cyphosoma are found, upon,
or embedded in flints. Vertebrates are rare, teeth of Lamna and
Corax excepted ; Ptychodus is very seldom met with.

Mr. Frederick Chapman has given a list of the Foraminifera
from this horizon i^Proc, GeoL Assoc. , vol. xiii, 1894, p. 369).

From a small working at Cox's Mount, Charlton (25), the
author has obtained fossils indicative of the M. cor-anguinum-
zone fauna; and from Westcombe Park Echinoconus conicus^
Cyphosoma konigi^ and the carinated form of Micraster cor-
anguinum, have also been obtained ; fossils which mark the
upper part of this zone.

WESTERHAM, KESTON, AND OTFORD.

Near the top of the hill, north of Westerham (26), the
Rhynchonella cuvieri-zont occurs.

The exposure about a mile south of Keston (27) is interesting
from the ^ct that the fauna and the lithological characters are
nearly identical with those of the chalk of the Gravesend area.
The beds themseUes are possibly of a slightly lower horizon.
No authenticated specimen of Belemnites has been seen by the
writer from this pit, but it is highly probable that some may yet

488 G. E. DIBLEY ON ZONAL FEATURES OF THE CHALK PITS

and Holaster trecensis are obtained in the lower pit together with
Ammonites rhotomagensis. The Chalk Marl is of a creamy colour,
and easily distinguished from the overlying white beds. The
upper portion of the lower pit contains the AcHnocamax pknus-
zone, and above it occurs a hard band, locally known as " soap,"
containing casts of Inoceramus mytiloides {=Iabiaiu5\ and
forming the division between the lower and the upper pit. In
the upper pit nearly 300 ft. of chalk are exposed, consisting of the
Rhynchonella aivieri-zoxM^ the Terebratulina gradiis-zone^ and the
Hoiaster pianushtds. The same features in the chalk are met
with here, 600 ft. above the river, as at Whorne's Place, Cuxton,
and Echinoconus subrotundus and Pentacrinus are plentiful.
Owing to the steep angle of the workings in this and in the Cuxton
district, it is difficult to determine the exact limitation of the zones
by personal collection of the fossils. Micrasters are very rare ; I
have found Micraster cor-bavis and Micraster ieskei. Vertebrates,
chiefly fishes, occasionally occur. Otherwise the pits have yielded
a rich fauna, as exemplified by the list at end of this paper and
the specimens in the British Museum.

Messrs. Tingey and Co.'s large pit (11) is situated half-a-mile
north of Wouldham. The chalk is worked to a depth of about 80
ft, the base of the pit being about 30 ft. above the river. Echino-
conus subrotufidus is faiily abundant. The zones are those of
Terebratulina gracilis and of Rhynchonella cuvieri.

Borstal Manor Pit (12), owned by Messrs Booth and Co., is
situated about a mile north of that last described. The section
here worked is about 70 ft. The chalk and its fossils correspond
with those of the upper part of the Whorne's Place pit on the western
side of the Medway. Holaster planus^ Terebratulifia gracilis^
Rhynchonella cuvieri^ and Pentacrinus are found in this pit ; while
on the opposite side of the river, at Messrs. Martin and Earless pit
(2) and at a slightly lower elevation the first three low -zonal fossils
are not met with. The hard blocky chalk with few flints is seen
in this pit and there is a well marked band of large flints about
20 ft. from the top. The zones are those of Holaster planus and
Terebratulina grocili:. Three prominent marly bands are seen in
the disused portion of the pit, one just under the flints, one near
the centre, and a third near the base.

Cliffe (13) is about five miles north of Strood. — The chalk
here is worked for about 70 ft., and is of the same lithological and
zoological facies as that in the Gravesend area, being very soft
and friable. It contains decidedly higher zonal forms than those in
the neighbourhood of Strood. The carinated form of Micraster cor-
angiunum,2i\^oEchinoco?iusconicus, Cyphosoma konigiy Actinocamax
verus^ and A. merceyi are common; A. westphalicus has been
obtained. From the association of these fossils we should expect
to find traces of the Afarsupifeszowe, Information on this point
is desirable.

IN THE ROCHESTER, GRAVESEND, AND CROYDON AREAS. 489

GRAVESEND DISTRICT.

Gravesend, Northfleet, Swanscombe, AND Farningham
Road (numbered 14 — 25). — AH the pits in this district are at
about the same horizon, viz., that of Micros ter cor-anguinum.
The chalk is very soft, and the flints form prominent bands, both
nodular and tabular.

The fauna includes the carinated form of Micraster cor-
angidinum, which is abundant, also Echinocorys vulgaris with its
varieties, and Echinoconus conicus. The Echinoconus is typical,
and there is also a well-marked variety somewhat resembling
E, subrotundus of the Rhynchonella cuvieri-zont,

Janira quinquecostata is but rarely found. Dr. Arthur Rowe
obtained a specimen of Holaster placenta from this area (Tol-
hurst's pit, 15).

Mr. Frederick Chapman has given a list of the Foraminifera
from this horizon {Proc, Geol. Assoc.^ vol. xiii, 1894, p. 369).

From a small working at Cox*s Mount, Charlton (25), the
author has obtained fossils indicative of the J/, cor-anguinum-
zone fauna; and from Westcombe Park Echinoconus conicus^
Cyphosoma konigiy and the carinated form of Micraster cor-
anguinumy have also been obtained ; fossils which mark the
upper part of this zone.

WESTERHAM, KESTON, AND OTFORD.

Near the top of the hill, north of Westerham (26), the
Rhynchonella cuvieri-zonQ occurs.

The exposure about a mile south of Keston (27) is interesting
from the fact that the fauna and the lithological characters are
nearly identical with those of the chalk of the Gravesend area.
The beds themselves are possibly of a slightly lower horizon.
No authenticated specimen of Belemnites has been seen by the
writer from this pit, but it is highly probable that some may yet

492

LIST OF FOSSILS FROM THE CHALK

present visible, the excavation of a few feet of the floor of the pit
would no doubt expose it.]

The Oxted Lime Pit (34) is situate in the -ff. cuvieri-y
Actinocamax plenus- and Holaster subglobosus-zones, Discoidea
cytindrica occurs.

In conclusion, I beg to tender my sincere thanks, for assist-
ance in the preparation of this paper, to Dr. A. Smith Wood-
ward, Mr. G. C. Crick, Mr. A. J. Jukes-Browne, Mr. Henry Woods,
Mr. F. Chapman, Dr. G. J. Hinde, Mr. E. T. Newton, Dr. F. L.
Kitchin, and particularly to Dr. Arthur Rowe, and Mr. C. D.
Sherborn for their invaluable aid in naming and zoning the fossils
in the following list

LIST OF FOSSILS FROM THE CHALK OF THE ROCHESTER,
GRAVESEND, AND CROYDON AREAS.

In the table of fossils the pits are referred to by the numbers
used in the descriptive text and on the maps ; the letters following
the number referring to the zones^ as follows :

a s= Zone of Micraster cor-angumum.

^= „ ,f cor-teshtdmarium.

crs „ Holaster planus.

</ = „ Terebratulina gracilis.

e ^. „ Rhynchonella cuvieri,

/= „ Actinocamax pUnus.

gss „ //olastfr subglobosus.

h=, „ Chalk Marl.

In those cases where it is difficult or impossible to exactly fix
the zone from which the fossil came, the number of the pit alone
is given.

Pits 1 4-2 2, so often quoted, are those in the Gravesend area.
They are all in the Micraster cor-anguinum-zone^ and may be
separately enumerated for convenient reference as follows :

14. Messrs. Fletcher & Co,

15. Messrs. Tolhurst & Co.

16. The London Portland Co.

17. Messrs. Beavan & Co.

18. Messrs. Kirby & Co.

Plant Remains.
Coniferous wood

Invertebrata.
Helerostinia obliqua^ Benett

19, 20. Messrs. White & Co.

20. Swanscombe.

21. Greenhithe.

22. Draper's Pit.

I «; 1 g\ ^og; 14a; zoa; 32 «/.

16^

Siphonia kdnigi^ Mant. . , .4.

Flinthosella, s^^ ia\2a\ zh\ ^c,d\ 13 a; 14-22 a;

24 /J ; 27 tf ; 30 a ; 31 <5.
CosciHopora infundihuliformtSy Goldf. . 14 a ; 26.
Ventriculites decurrens^ T. Smith . 4 r, </ ; 10 f , </ ; 28 <x ; 33 c.

„ mammiUaris^ T. Smith . 4 f, r/ ; 10 c, </ ; 28 a.

„ impressus^ T. Smith . 4^, </; 28.

OF THE ROCHESTER, GRAVESEND, AND CROYDON AREAS. 493

VentrkuWes radiatus^ Mant.

f, akyonoides^ Mant. .

Pharetrospongia strahani^ Sollas.
Porosphtrra globularis^ PhiL

„ piUoluSy Lam. . ■ .

„ (branching form) .

CtphaliUs longiiudinaliSy T. Smith

„ caUni/er^ T. Smith

„ pirforatuSy T. Smith .

Camerospongia capitatay T. Smith

Plocoscyphia convolutUy T. Smith .

Parasmilia centraliSy Mant.

„ granulatay Dune.

,f cylindrical £. & II.

Axogaster cretaaay Lonsd. .
Synheiia sharpeanay M. Edwds.

Bourguetkrinus iilipticusy Nils., varr.

Pcntacrinus (columnars)
Ophiura serrata^ Roeraer
Ona^ler obtusus, P'orbes
Miiraster hunteriy Forbes

„ rugatus f Forbes
Pentagonastir megaloplaXy Sladen
Metopaster parkinsoniy Forbes

„ mantelliy Forbes
Calliderma latum y Forbes .
Nymphastcr coombii f Forbes
Ctdaris sceptnferay Mant. .

yy clavigiroy KOnig
„ perornatay Forbes .
„ hirudo, Sorig. .
„ Sirriferay Forbes .
Cyphosoma kdnigiy Mant.
„ coroUarey Klein .
,, radiatum, Sorig.
Echinocorys vulgaris y Breyn.
Echinaconus contcuSy Breyn.
,» » var. .

„ subrotunduSy Mant.

., castatuay Brongn.

Discoidea dixoniy Forbes

„ cylindrkuy Lam. .
Pseudodiadema ornatunty Goldf,
Micr astir lor-anguinuniy Leske

„ „ var. latiory Rowe

„ pra^cursor (group)

„ CGr-ttstudinariuniy Goldf.

„ leskeiy Desm.

„ cor'bovisy Forbes

Epiaster gibbuSy Lam. .
tiolasUr planus y Mant.

„ placenlOy Ag.

I a-y 4 ; 10 ; 14-22 a ; 30 «.

14-220 ; 24a.

I a-y 14 a ; 24 a ; 27 a.

la; 2ayb'y Zb\ ^byCyd-y lOCyd; 130;

14-22; 240; 27 a; so a.
14-22 a; 240; 30a; 31 4.

14 a.
4; 10.
4.

4.
4.

la; 2 ay b-y 4- by c ; 10 byC; 14-22 a ;
24 «; 26; 3011; 31^; 33c.

If ; 4; i4-22a; 24a; 27; 30a.
14-22 a.
14-22 a.
1g\ IOC.
30 tf.

la-ylayb-yZbyCylOCylla-y 1422 If,

24«; 30a; 31^; 33^.
4f ; loc'y 12 c; 32 1; 33c.
15.7.

15 «.

14-150; 27 a.
140.

14-150; 240; 270.

15 «.

150.

140.

15 «.

10; 20; 4/5; 14; 220;240; 270;

300.
4f ; 14-22 0 ; 240 ; 270.
140; 17 a.
4C'y 3ZC.
14-22 a.

10; 130; 14-220;; 240; 270; 300,
130; 14-220 ; 240 ; 300.

4c; lOC'y l2C'y ZlC'y HC,

All pits containing zones 0 to c,
I a-y 130; 14-220; 240; 270.
130 ; 14-22 a ; 270.
4^; Sfl'; lod'y 110; 26; 28; 32tf;

Zld.
5^; 10^; 34/.
26.

^g\ 1g\ I4g'

log,

i; 2; 13; 14-22; 24; 27; 30; 31.

14-220 ; 270.

Zbyc;4b,cyd', 5 ; 31^; i^byc; 33 f.

3; 4; 31.

3; 4.

4c ; loc.

10; 130 ; 14-22 a ; 240; 270 ; 300.

4; 5 ; 10; 12 ; 32; 33.

i5'»; 30 «; 31^.

492

LIST OF FOSSILS FROM THE CHALK

present visible, the excavation of a few feet of the floor of the pit
would no doubt expose it.]

The Oxted Lime Pit (34) is situate in the J^. mvieri-^
Actinocamax plenus- and Holaster subglobosus-zonts. Discoidea
cylindrica occurs.

LIST OF FOSSILS FROM THE CHALK OF THE ROCHESTER,
GRAVESEND, AND CROYDON AREAS.

In the table of fossils the pits are referred to by the numbers
used in the descriptive text and on the maps ; the letters following
the number referring to the zones^ as follows :

a s= Zone of Micraster cor-anguinum.

^ ^ „ „ cor-tesiudinarium.

f = „ Holaster planus,

</ = „ Terebratulina gracilis,

^ = „ Rhyncli4inella cuvieri,

/:= „ Actinocamax plenus.

g ^ „ Holaster subglobosus.

h^ „ Chalk Marl.

In those cases where it is difficult or impossible to exactly fix
the zone from which the fossil came, the number of the pit alone
is given.

Pits 14-22, so often quoted, are those in the Gravesend area.
They are all in the Micraster cor-anguinum-zont^ and may be
separately enumerated for convenient reference as follows :

14. Messrs. Fletcher & Co,

15. Messrs. Tolhurst & Co.

16. The London Portland Co.

17. Messrs. Beavan & Co.

18. Messrs. Kirby & Co.

Plant Remains.
Coniferous wood

INVERTEBRATA.
Hettrostinia obliqua^ Benett
Siphonia Idnigi^ Mant. . , .4.

Plinthosella, spp \ a \ 2 a \ I b -, \c,d \ l^a \ 14-22 a ;

24 /z ; 27 <x ; 30 a ; 31 ^.
Coscinopma infundibuli/ormis^ Goldf. . 14 a ; 26.
Ventriculites decurrens^ T. Smith . 4 <:, </ ; 10 f, // ; 28 « ; 33 r.
„ mammillaris^ T. Smith . 4 r, r/ ; 10 t, ^/ ; 28 a.

„ impressus^1.SiCi\\\i . 4^, </; 28.

19, 20. Messrs. White & Co.

20. Swanscombe.

21. Greenhithe.

22. Draper's Pit.

I « ; 7g] 10 ^ ; 14 a ; 30 a ; Z2 d.

16 a.

OF THE ROCHESTER, GRAVESEND, AND CROYDON AREAS. 493

Ventriculifes raJiatus^ Mant.

„ alcyonoidiSy Mant. .

Pharetrospongia sirahani^ SoUas.
Porosphaera globularis^ Phil.

„ piUolus^ Lam. . •
„ (branching form) .
Cephalitis longitudinalis^ T. Smith
„ catenifer^ T. Smith
„ perforatuSy T. Smith .
Camerospongia capitata^ T. Smith
Plocoscyphia convoluta^ T. Smith .

Paraimilia centralis y Mant.

ti granulatUf Dune.

„ cylindrical E. & H.

Axogaster cretacea^ Lonsd. .
Synkelia sharpeana^ M. Edwds.

Bourgueticrinus ellipticus^ Nils., varr.

Pentacrinus (columnars) .
Ophiura serrata^ Roemer .
Greasier obtusuSy Forbes
Afitraster hunteri, Forbes .

„ rugatus t Forbes .
PentagOHoster megaloplax^ Sladen
Metopaster parkinsoniy Forbes

„ mantelliy Forbes
Calliderma latum, Forbes .
Nymphaster coambii t Forbes
Cidaris sceptrtfera, Mant. .

,f clavigera, KOnig
„ perornata, Forbes .
„ hirudo, Sorig. .
„ serrifera, Forbes .
Cyphosoma kdnigi, Mant.
„ corollare^ Klein .
„ radiatum, Sorig.

Eckinocorys vulgaris, Breyn.
Echinoconus contcus, Breyn.
„ „ var. .

„ subrotunduSj Mant.

., castanea, Brongn.

Discoidea dixoni, Forbes

„ cylindrica, Lam. .
Pseudodiadema ornatum, Goldf.
Micraster tor-anguinum, Leske

„ „ var. latior^ Rowe

„ prftcursor (group)

„ cor-testudinarium, Goldf,

„ leskei, Desm.

„ cor-bot'isj Forbes

Epiaiter gibhus. Lam. .
H cluster planus, Mant.

„ placenta, Ag.

la; 4; 10; 14.22 a ; 30 a.

i4-22a ; 24a.

I a\ 14 a ; 24 a ; 27 a.

la; 2a,b', ib\ 4b,c,d', I0c,d; iza;

14-22 ; 24 a; 27a; 30a.
14-22 a; 24 a; 30a; 31 ^.

14 a.
4; 10.
4.

4.
4-

Iff; 2 a, b; 4 b, c ; lO b,c; 14-22 a ;
24a; 26; 30a; zib; zzc

If ; 4; i4-22a; 24a; 27; 30a.
14-22 a.
14-22 a.
7g; IOC.
SO a.

la; 2a,b; 3<5, t; 10^; 13 a; 1422 a,

24<i; 30«; 31^; 33^:.
4C', IOC, 12 c; 12 c, izc.

15 a.
15 «.

14-15 «; 27 a.

14 a.

14-15 «; 24 a; 27 a.

15 «.
15 «.
14 «.

la; 2a; 4b; 14; 22a; 24a; 27a;

30 a.
4<r; 14-22 a; 24 a; 27 a.
14 a; 17 a,
AC, Zlc
14-22 a.

la; 13 a; 14-22 a ;| 24 a; 27 a; 30a.
13 a ; 14-22 a ; 24 a ; 30 a.
4<r; IOC, I2c; 32 <: ; 33c.
All pits containing zones a to c.
I a; 13 a; 14-22 a; 24 a; 27 a.
13 a ; 14-22 a ; 27 a.
4d', Sd; 10 d; 11 a; 26; 28 ; 32 a;

Se; lOif ; 34/.
26.

6^; 7g\ 34^.

10^.

i; 2; 13; 14.22; 24; 27; 30; 31.

14-22 a ; 27 a.

Sb,c, 4^iC,d; 5 ; 31^; I2b,c, 33 f.

3; 4; 31.

3; 4.

4c ', IOC.

I a ; 13 a ; 14-22 a ; 24 a; 27 a; 30a.
4; 5 ; 10; 12; 32; 33.
iS^'i 30a; 31^.

494

LIST OF FOSSILS FROM THE CHALK

HolasUr irecensis^ Leym. .
„ subglobosus^ Leske
CardiasteVy large n. sp.

Serpula ampullaaa^ Sby. .
„ fluctuata^ Sby.
„ ilium y Sby. .
„ macropuSy Sby.
„ piana, S. Woodw. .
„ /^x«j, Sby. .

Crania parisiensiSy Defr.
Ttiecidea wethtrelli^ Morris .
Kingiua lima^ Defr. .
Ttrebratulina striata^ Da v. .
„ gracilis^ Schl.

Terebratula stmiglobosay Sby.

„ carnea^ Sby. .

Rhynchonella reedinsisy Elh.

„ cuvieri, d*Orb.

„ tuoodwardi, Dav.

„ piicattiiSy Sby.

„ octoplicata^ Sby.

„ maniellianay Sby.

Picten nitidusy Mant. .

„ arachnoideSy Defr.

„ cottcentricuSy Woodw

„ beaver iy Sby. .

„ jugosusy Sby. .

„ orbicularis y Sby.

„ n. sp.

„ n. sp.
Janita quinguecostaiUy Sby.
Spondylus sptnosusy Sby.

„ dutempkanuSy d'Orb.

„ laiusy Sby. .

„ JimbriatuSy Sby.
Lima hoperiy Mant. .

„ granosa, Sby.

„ aspera, Mant.

„ parallehy Sby. .

„ n. sp.
Osirea vesicular is ^ Lam.

„ normaniana, d'Orb.

„ semiplanay Sby.

„ curvirostriSy Nils.

„ hippopodiumy Nils.
Exogyray sp.
Anemia, sp.
Plicaiula sigillinay Woodw.

7^; 9^; log.

7 ; 9 ; 10 ; 34.

I a.

I a; 7^; 9^; lo^; h"^.

I a ; 14-22 a.

la; 4.
I a.

I a ; 14-22 a,
I a 'y 1422 a.

14-22 a; 24a; 27a.

14-22 a ; 24a.

14-22 a ; 24 a.

i2C'y 24a; Zib'y 32c.

4^, r; 10^, c; I2t, rf; 27/1; 31 3 ;

32t:,^; 33t.
la; 2«,^; ZaybyC; \byCyd\ ^Cyd\

lOCyd; iidyC'y 12 Cyd\ 13 a;

14-22 a ; 24 a ; 27 a ; 30 a ; 31 a.

29^; 3P«; 31 <5; 34^.

13 a; 14-22 a; 24a; 27 «.

4c,</,/; 5c,</,^; lOCydye; 12 c,d;

32Cyd'y Z^Cyd.
4 r ; 1 2 c.

4^, f; I2r; 13a; 14-22 a,
13 a ; 14-22 a.
10^.

la; 13a; 14-22 a; 24a; 27a; 30a.
14 a.
30 a.

9^; log,

9g\ log,
log] loyi.
SO a.
log,
10 g.
log.
iga.

14a ; l6a-y 31 b.
All pits containing zones a to c.
14 a.

la; 11 a \ 14-22 a ; 27 a.
4; 14 a; I5rt ; 24 a.
1 a \ 2 a, b'y 4 byC'y ^ byC\ 10 ; 12 ;
13 a; 14-22 a; 30a; 31^; 32 c.
14 a.
10^.
10^.

33.

la; IOC 'y 13 a ; 14-22 a.

4b^c\ 13a ; 14-22 a; 24a.

14-22 a.

i(i\ 4-

lg\ log.

7g] log.

it a.

la y 14a,

OF THE ROCHESTER, GRAVESEND, AND CROYDON AREAS. 495

Plicatula barroisi^ Peron

„ inflata^ Sby. .

,( pectinoides^ Sby. .
Pinna decussata, Goldf.
Inoctramus lamarcki^ Park.

„ striatus^ Mant. .

„ cuvuriy Sby.

„ invo/utits, Sby. .

„ crips t\ Mant. .

„ aiatusy Goldr. .

„ iingua^ Goldf. .

„ latus, Mant.

„ labialus^ Schl. .

Panopofa^ sp. .

Arca^ sp

Pholadomya decussaia^ Phil.
Isocardia^ sp. .
Radiolites mortoni^ Mant. .
Teredo amphisbaena^ Goldf. .

Turbo gemmatus, Sby.
PUurotomaria per spec tiva^ Mant.

Solarium orna/umy Sby.

Nautilus pseudoelegans t d'Orb.

„ deslongschampsianuSy d'Orb.
BaculiteSy sp. .
Scap kites aqualis^ Sby.
„ ooliquuSy Sby.
Ammonites leptophyllus (group)
,, pachydiscus

„ rhotomagensiSy Brongn.

„ coupei^ Brongn. .

„ varians^ Sby. .

,, mantel liy Sby. .

„ n. sp. .
Turrtlites costatus^ Lam.

„ tubercu/atus, Bosc
Actinocamax verus^ d'Orb. .

„ merceyiy Mayer- Rymer

,. westphalicus^ Schl liter

plenuSy Blainv.
„ n. sp. .

AptycHus ....
Beak of Cephalopod .

Pollitipes unguis^ Sby. .
Scalpellum arcuaium, Darwin

„ maximum^ Sby. .

Enoploclytia Uachiy Mant. .

\C\ 12C\ lie,

10 >5.

1i\ ^og; Mg,
log: 14a; 24a.
2 ; 10 a.

iO.

2; 3c\ 4f ; 5; loc.d; 12; 26; 28;

3Zd.
la; 10 a.
log,

4.
loc.d f

4.
10/.

10 >i.

10 4.

10 i.

10 ^

4^ ; 7c ; 8r ; lod^e? ii c;

4; 7g; log; 15^; 33^.

Zld,

ioc,d?

la; 2ayb; ^b,c,d; gg; 14-22 a ;

I2b,c.
9g'

10^; 12 d.
h,

10 h.
10 h,
10 A,

15 «.

4d; I2d; nd.

10 h,

10 h.

log.

10 h,

10 h.

11 a; 14-22 a,

la ; II a ; 14-220.
II a,

7 ; 8 ; 9 ; 10 ; 34.

14 a.

16 a.
14 a.

4c : lOr, </? 14 a ; 24 a.

30 rt.

14 a; l()a.

4; log; loa; 32^/.

Vertehkata.

AnomtFodus cretaceus^ Ag. .
Apateodus striatus, Ag.
Cestracion rugosus^ Ag.
Cimoltchthyi letoesiensiSj Leidy

15a; 30a ; lib,

10^.

I ^ ; 33 ^.

30a; 33.

496

E. T. NEWTON ON A REMARKABLE BONE

Cladocyclus lewesitnsis^ Ag. .

Corax falcatus^ Ag.

Citnothrissa (^Beryx) microcephalus^hg,

Dircttis elongatus^ Ag.

Edaphodon mantilli^ Buckl.
„ sp. .

Enchodus^ sp. .

Gyrodus angustidtns^ Ag. .

Homonotus dorsaiiSy Dixon .

IchthyodtcteSy sp. .

Lamna appendiculata^ Ag. .
„ macrorhiza^ Cope .
,f sulcata^ Gein. .

Afacropoma mantelli^ Ag.

Notidanus microdon, Ag.

Oxyrhina manUlli^ Ag.

„ angustidem^ Reuss

„ macrorhiza^ Pict. and Camp

Pachyrhizodus gardneri^ Mason
„ n. sp. .

PUthodus oblongusy Dixon .

PortHeuSy sp.

Protosphyf'trna^ sp. . ,

Plychodus altior^ Ag. .

„ mammillariSy Ag.

„ latissimu^y Ag. .
„ rugosuSy Dixon .
„ decurrens^ Ag.
„ depressusy Dixon, var.
„ liFviSy A. S. W. .
„ pauctsulcatus, Ag.
M polygvrus, Ag. .
Scapanorhynchus gigaSy A. S. W.
,, rhaphiodoHy Ag.

„ subulaiuSy Ag.

Shark vertebra? .
Tomognathus mordax^ Dixon
„ sp. .

Chelonian remains
Polyptychodon inUrrupius^ Owen
Reptilian (paddle-bone)
Rhynchocephalian ? .

7c; \oc\ 10 a.

4; loc.dt 14-22 a; 30a; 31^; 33-

10^.

4; 10^.
10^.

9^; 10^; 30a.

4; 9^; 10^; 30tf; 31^; 33.

33^.

10^.

30 a.

All pits containing zones a to g,

\\a.

11; 33.

10 r.

10^; 3o«.

All pits containing zones a\jo c.

ig\ i4«; i5«; 33.

10 e,

^g\ 10^.
10^.
4^; 10^.

4^; lOjf.
4^; ig\ log.

lOCyd} 12; 31 b\ 33.

4r. f/; S^»<^; 10 c,di\ lid; 12 d \

ZlCyd.
4; 10 c.d^e] 12 d; 1$^] 28; 30^?.
la] 30 <i.

6^; 7g\ 9g'y log; 3>Ag'
(^g\ 1g\ 9g\ log;
log.

4 ; 10 Cyd.f; II ; 12 c,d?
7g; lod.f? iia; nd; z\g,
4; lod.e-i 15 «.
4; lod.e}
10; I4tf ; 30a ; 33c.
10 ; II ; 15 a,
Tg\ log.

4; loc.d} 33^/.

4 ; 8 ; lOfl'; ^? 31 3.

10^.

4^.

APPENDIX.

ON A REMARKABLE BONE FROM , THE CHALK OF CUXTON,

POSSIBLY REFERABLE TO THE RHYjNCHOCEPILVLIA.

liv E. T. NEWTON, F.R.S., F.G.S., F.Z.S.

Our fellow member, Mr. G. E. Dibley, an indefatigable collector
of Chalk fossils, some time ago placed in my hands a remarkable
fossil bone from the Chalk of Cuxton. Its horizon is probably
the Rhynchonella cuvieri-zont, and it was obtained from the pit
worked by Messrs. Weekes and Trechmann (see p. 486). I am
unable to speak definitely of the affinities of this specimen, yet

FROM THE CHALK AT CUXTON.

497

it seems to me very probable that it will prove to belong to the
Rhynchocephalia, that remarkable group of lizard-like animals
which includes the living New Zealand Tuatera or Hatteria <•>*,
and the Triassic Hyperodapedon^-^^ I have ventured to give a
short account of this bone in order that other workers may be
on the look-out for additional specimens which may give a further
clue to its true systematic position.

This bone, which is represented one and a half times natural
size in figure A, below, is 44 mm. long, 7*5 mm. wide at the
broadest part, and not more than 4 mm. thick. It is still attached
to the matrix, which is a hard, greyish chalk. One side of the
bone is nearly straight, and forms a sharp edge ; the opposite side
is curved and thick, so that the bone tapers away towards both

"•?f ^ .♦- #«•

Dentigerous Bone from the Middle
Chalk of Cuxton. A x 5 ; B, Middle
Portion, X 3-

extremities, one end being narrower than the other. The thick
edge shows a deep depression, extending from near the middle
of the specimen to the narrower extremity (a, a), which is evidently
the articulation for another bone.

The surface of this specimen, which still adheres to the matrix,
is concave from end to end, while that which is exposed is convex
in the same direction and occupied by three or four longitudinal
rows of conical tooth-like nodules. A series of comparatively
large nodules runs parallel with, and close to, the straight margin.
The nodules are best shown towards the narrow end of the bone,
being much denuded (probably by attrition during life) at the
broader end. A second row of smaller nodules runs parallel with,
but is separated by a distinct groove from, the larger one, and like
it extends from end to end of the bone. A third row of small
nodules occupies the middle third of the convex side of the bone,
and three or four nodules are to be seen on the extreme margin.

* The figures in brackets (6) refer to the list of works at the end of this Appendix.

Proc. Geol. Assoc, Vol. X\'I, Part 9, August, 1900.] 37

493 E. T. NEWTON ON A REMARKABLE BONE

At both extremities the nodules are denuded, but this is especially
the case at the broader end where, for nearly half the length of the
specimen, the nodules are almost obliterated.

When examined with a lens this denudation is found to consist
for the most part of small parallel grooves, generally in sets of
three or four together, but the grooves in different sets are
variously orientated, and are found upon most of the nodules,
with the exception of a few in the middle of the bone.

There is little doubt that these nodules are teeth, for although
so intimately connected with the supporting bone as to show no
line of demarcation, yet in this respect they are like the teeth of
Hyperodapedon ^' * and Sphenodon <*\ Judging from the form
of the specimen it is probably either a palatine or a pterygoid
bone.

It is by no means clear whether the denudation of the teeth
took place during the life of the creature, and was due to the
crushing of some hard substance taken as food, or whether it is
to be attributed to some post-mortem cause.

The close resemblance between these teeth and those of
Hyperodapedon is very striking, and leads me to think that the
specimen will eventually be found to be related to the Rhyncho-
cephalia, although a comparison with the known forms of
these creatures throws no further light upon the nature of this
specimen.

In Hatteria <*' {Sphenodon punctatus) the living representative
of the Rhynchocephalia, there are, in the upper jaw on each side,
two rows of teeth attached to the maxilla and palatine bones,
between these two rows there is a groove into which bites the
single row of teeth supported by the ramus of the lower jaw. The
longitudinal groove in the Chalk specimen bears some resemblance
to that of Sphenodon ; but in the latter the groove is between the
teeth of two distinct bones (the maxilla and palatine) while in
the former it appears to run along the middle of a single bone.

The species of Hyperodapedon '^•^•" from Elgin, Devonshire,
and India have each several rows of teeth in the upper jaw, and
these are nodular, peculiarly facetted, and worn into a groove by
attrition with the lower jaw. The specimens hitherto met with
have the teeth on each side of the upper jaw attached to what
appears to be a single bone, and in this respect, therefore,
resemble the Chalk fossil ; this bone, however, is believed to
be the united maxilla and palatine bones. Moreover, in all the
examples of Hyperodapedon, the bone in question is very solid and
strong, while the Chalk bone is thin and slender. Rhynchosnurtis
^"'"'j having a more slender head than Hyperodapedon, may
perhaps have a palate more resembling Mr. Dibley's specimen ;
but the known examples of the upper jaws and palate have the
teeth too much obscured to allow of comparison. For similar
reasons no satisfactory comparison can be made with Homaosaurus

FROM THE CHALK AT CUXTON. 499

and other small Jurassic genera ^** ^% which are included in the
Rhynchocephalia.

The Eocene and Cretaceous genus Champsosaurus of Cope
rt.3.4.« although related to the Rhynchocephalia has a very
different type of dentition. The skull and snout are much
elongated ; the teeth of the maxilla are long and slender, and all
the bones of the palate bear small conical teeth, generally in
several rows ; but these teeth are quite unlike those of the Chalk
specimen.

While calling attention to these various forms, I am fully aware,
as I have already stated, that there are no sufficient grounds to
justify a certain reference of this Chalk fossil even to the group of
the Rhynchocephalia; but at the same time the peculiarities of the
teeth apparently find their nearest counterparts in this group, and it
seems to me prol)able that the bone is a palatine or pterygoid of
some such an animal as Hatteria or Rkynchosaurus,

The possibility of this bone belonging to a fish has been
considered, but I am not acquainted with any piscine form of teeth
which might indicate a closer relationship than that which seems
to exist between this bone and the Rhynchocephalia.

At present Mr. Dibley*s specimen is a puzzle, but in the hope
that by publication the problem may be solved, I have ventured
to bring this notice of the fossil before the readers of the
Proceedings.

Literature of Rhynchocephalia referred to in the Text.

1. BoirLEXGER, A.— "On British Remains of Homa?05:iurus, with remarks

on the classification of the Rhynchocephalia." Froc. Zool. Soc.^ 1891,
p. 167.

2. Cope, K. Ti,— Report U.S. Geol, Surv. Terr., vol. iii, 1884, p. 104.

3. DOLLO, L. — " Premiere note sur le Siraoedosaurus d'Krquelmnes." Bull.

Mus. Roy. if Hist. Nat. Belg., Tome iii, 1884, p. 151.

4. . — ** Sur I'identite des genres Ckampsosaurus et Sinurdosaurus.^*

Revue de Questions ScientifiqueSy Juillet, 1885.

5. . — •' Nouvelle note sur le Champsoiaure, etc." Bull. Soc,

Beige d, Geol., Tome v, 1892, p. 147.

6. Gunther, a — " A Contribution to the Anatomy of Hatteria {Rhyncko-

cephalut, Owen) " Fhil. Trans., 1 867, pt. ii, p. I.

7. H UXLEY T. H — "On Hyperodapedon.'* Quart. Journ. GeoL SoCy vol. xxv,

1869, p. 138.

8. . — "Further observations on Hyper odapedon.'* Ibid., vol.

xliii, 1887, p. 675.
9. Lydekkeu, R. — Palivontologia Indica., Ser. iv, pt. 5, 1885.

.—"Cat. Foss. Rept. Brit. Mus.'* 1888, pt. i, p. 290.

. — " Manual of Palaeontology," 1889, vol. ii, p. 1131.

10. Meyer, H. von. — " Zur Fauna d. Vorwelt. Reptilien aus dem litho-

graphischen Schiefer." Frankfurt, i860.
. — PaUeontographica, Bd. xv, l86$-8, p. 49.

11. Owen, R. — Trans Camb. Phil. Soc., vol. vii, 1842. p. 355.

12. Zittel, K. a. von. — " Handbuch der Paloeontologie." 1889, Band iii,

p. S83.

500

EXCURSION TO EASTBOURNE AND SEAFORD.

May 26th, 1900.

Director : C, Davies Sherborn.

Excursion Secretary : A. K. COOMARA-SWAMY, F.G.S.
{Report by The DIRECTOR.)

Several members, who had arrived at Eastbourne the night
before, met the Director at the Wish Tower at 9.30 a.m. The
party proceeded to the shore at Gore pit, and walking on the
Holaster subgiobosus-zon^, collected from the zone of Actinocamax-
pUnuSy an easily traced bed of blue marl varying from 10 to 15 or
more feet thick. At Holywell the A. plenus marls were seen to sink
into the shore, and the section here exposed passes through the
whole of the Rhynchofiella cuvieri beds and a great part of the zone
of Terebratulina gracilis. Meeting the official party at one o'clock, at
Cow Gap, the Rev. W. R. Andrews and Mr. Whitaker explained
the nature of the beds below the White Chalk at this point, point-
ing out the dome of Upper Greensand and Chloritic Marl and the
curious confusion on the shore, resulting in an alternation of Gault
and Upper Greensand, the result of either a thrust from seawards
or of the landslip landwards. Resuming the walk, the Director
pointed out the various zones of the White Chalk between this
point and Birling Gap, at which point the party divided ; the
majority returned to Eastbourne, but the Director and a few
members proceeded over the top of the Seven* Sisters to Seaford.
At the top of the last of the Sisters, the Director found and showed
plates of Uintacrinus.

The following day Mr. Sherborn conducted an un-
official excursion round Seaford Head, showing Marsupites and
Uintacrinus plates at the top and at the base of Seaford Head, the
grand exposure of the M. cor-testudinariumzowe^ and the Ac-
tinocamax-quadratuS'Zom, On this occasion the party were so
fortunate as to find two specimens of Terebratulina rowei in the
lower part of the guadratus-zont^ a specimen of Actinocamax
ffierceyi some fifty feet above the Afarsupite-band, and to trace the
variation of the Echinocoridce in their passage upwards from the
Uintacrifius-h2iX\d to the lower part of the Actinocamax quadratus-
zone, for although the cliffs were much sea-worn many fossils were
to be seen in section.

REFERENCES.

Ordnance Survey Six-inch Maps, Sheets 8g, 83, 82, 79, 78, 77, 76, Eastbourne

to Brighton.
Ordnance Survey One-inch Map, New Series, Sheet 334.

ROWE, A. W.— " The Zones of the White Chalk on the English Coast. I.—
Kent and Sussex." (Sections along the coast by C. D. Sherborn.)
Proc. Geol. Assoc. (iQCo), vol. xvi, pp. 321, 333.

Prog. Geol. Assoc, Vol. XVI, Part 9, August, 1900.]

SOI

EXCURSION TO BOXMOOR.

Saturday, May i2TH, 1900.
Director: Upfield Green, F.G.S.

Excursion Secretary : A. K. COOMARA-SWAMY, F.G.S.

The Geologists left Euston Station by the 12.25 p.m. train, and on
arrival at Boxmoor walked to Bennet's End, Hemel Hempstead^

in order to examine some sections of Lower London Tertiaries and
brick-earths.

There are two pits situate on a plateau at about 450 ft. O.D.

Proc. Geol. Assoc., Vol. XVI, Part 10, November, 1900.J 38

502 EXCURSION TO BOXMOOR.

The more northerly pit (A on plan), is worked for brick-earth
chiefly, and shows a section of about 20 ft. of brownish clay with
a few pebbles, overlying a bluish-grey clay with many pebbles.

In the pit marked B, from five to six feet of gravel, con-
taining large pebbles of quartzite and sandstone, with blocks of
sarsen-stone and rolled fragments of pudding-stone, are seen
resting on a reddish brick-earth (a little more sandy than that
seen in pit A) laminated, and traversed by veins of pipe-clay.
From twenty to twenty-five feet of this brick-earth had been dug
down to a boss of chalk. Such bosses of chalk, covered with
green-coated, rolled and un-rolled flints, are frequently met with
: in this district, sometimes in the brick-earth and occasionally
projecting into the gravel.

South-eastward of the above-mentioned pits, along the line
No. I on plan, occurs a ridge of chalk, its eastern side sloping at
an angle of 75*-8o*. The surface of the slope is hard, polished,
striated, and covered with a layer of black clay. Against this
"wall" of chalk rests, horizontally, a bluish-grey plastic clay,
part of the Reading Series, surmounted by about 12 ft. of
the Basement Bed of the London Clay containing characteristic
fossils, teeth of Lamna, etc.

c^.*. r^^^/cHMH

Fig. 2.— Section at Rennet's End Brickfields.
Scale : 9 inches=i mile ; vertical scale exaggerated.

An old pit in the rear of Tilekiln Farm, described by
Mr. Whitaker,* was next visited, where 12 ft. of the Basement
Bed of the London Clay, with Reading Beds below, abut
against a wall of chalk. The direction of the fault and its
inclination will be seen on reference to No. 2 on the accom-
panying plan and section.

A cordial vote of thanks to the Director, genially acknowledged,
concluded a most interesting excursion.

REFERENCES.

Geological Survey Map, Sheet 7.

Ordnance Survey Map, New Series, Sheet 238.

H. B. Woodward.—" Geology of England and Wales," and edition, 1887.
W. Whitakkr. — "Geology of London," vol. i, 1889, p. 208, fig. 36,
Mim. Geoi. Survey.

Upfield Green.— /Vor. Herts, Nat, Hist, Soc,^ vol. vi, 1892, p. Ixii.
* "Geology of London," vol. i, X889, p. 208.

SOS

EXCURSION TO MALVERN AND DISTRICT.

Whitsuntide, June 2nd to June 5TH, 1900.

IHrtctor: Prof. Theodore T. Groom, M.A., D.Sa, F.G.S.

Excursion Secretary: A. C. YoUNG, F.C.S.
{^Report by THE DIRECTOR.)

Saturdayy June 2nd, — The excursion commenced with a walk
along the eastern side of North Hill to the large quarry above
Malvern Link. The faulted and slickensided undulating surface
of the Archaean massif was seen to be admirably exposed, and
showed in places a coating of fault-breccia composed chiefly of
irregular pieces of Archaean rock set in a reddish paste of Triassic
material. The Archaean itself here, it was pointed oiit, consisted
chiefly of diorite with intrusive veins of granite. The latter rock
seemed to have very thoroughly penetrated and mingled with the
former, a process resulting in the production of a rock of
thoroughly mixed character. Many hand specimens were obtained
showing the most intimate inter-penetration of the two ingredients.

Passing up the depression containing the covered reservoir of
the Malvern waterworks, similar close relations betwefen the ai^ite
and a variety (homblendite) of the diorite, consisting largely of
hornblende, were observed in loose blocks which had fallen down
the slopes.

At the top of the hill the haze precluded enjoyment of the
whole of the wide panorama to be seen from this point, but during
the descent to West Malvern the chief features of the picturesque
country to the west were admirably seen. The May Hill Sand-
stone formed the slope in the immediate foreground. The
Woolhope Limestone at or near the foot of this slope formed no
very marked feature, but the Wenlock and Lower Ludlow Shales
formed vales on either side of the gently rising escarpment of
Wenlock Limestone, while the Aymestry Limestone with its
peculiar S-like curve rose up into a sharper ridge beyond; and
after dipping down beneath the Old Red Sandstone syncline of
Col wall, reappeared again as a fine escarpment near Ledbury.

The party next proceeded to the line of the great western fault
bounding the Archaean, and fine blocks of Miss Phillips* con-
glomerate with Stricklandinia and UndstrOmia were discovered
behind the houses west of Sugar Loaf Hill. It was here pointed
out that although many of the fragments in the conglomerate
closely resembled those of the adjacent hills, the latter were
probably buried by the conglomerate, and a considerable propor-
tion of the pebbles must have come from some neighbouring

Proc. Geol. Assoc, Vol. XVI, Part 10, November, 1900.I

EXCURSION TO MALVERN AND DISTRICT.

E.byK.

[Scale : 3 inches:=i mile.]

Fig. I.— Section across the Malvern Range immediately
North of the Dingle.

S.W.

Great Vinyard
Wood«

N.E.

High Wood.

Cowleiffh
Park.

Aw '

Arch,

[Horizontal scale: 3 inches=i mile. J
Fig. 2.— Section across Cowleigh Park and High Wood.

Tr. Trias.

Sh. Wen lock, or Lower Ludlow

Shale.
WLf. Wenlock Limestone.
WS. Wenlock Shale.
WLi. Wooihope Limestone.
TS. Tarannon Shale.

MS«. Upper Beds of May Hill

bandstone.
MSi. Lower Beds of May Hill

Sandstone.
Q. Cambrian Quartzite.
Arch. Archaean.
FF. Faults.

W.byS.

High Wood

E.byM.

HUS WLTS

[Scale: 6 tnche£=i mile.]

F^.

Fig. 3.— Section across High Wood and North Hill.

Tr. Trias.
WS. Wenlock Shale.
WLi* Wooihope Limestone.
TS. Tarannon Shale.
MS,. Upper Beds of May Hill
Sandstone.

MSi. Lower Beds of May Hill

Sandstone.
BS. Black Shales.
Arch. Archaean.
FF. Faults.

(Ai>». /— 7 rtprinted, by permission^ from tkt Quarterly Journal of the
Geological Society, vols. Iv. and hfi.)

EXCURSION TO MALVERN AND DISTRICT. 505

source. In the quarries on each side of the Dingle, or the
depression between Sugar Loaf Hill (the south-western elevation
of North Hill) and the Worcestershire Beacon, the May Hill beds,
imperfectly revealed, were seen resting against the Archaean.

In the quarry above, complex relations between the diorite and
aplite were again seen. Here the aplite appeared to have been
intruded into the previously foliated diorite, and both rocks to
have been sheared by subsequent movements.

The day's work was completed by a visit to the May Hill
conglomerates and the Archaean of Cowjeigh Park. Specimens
were collected from the presumed Cambrian quartzite, which was
found, after a short search, almost covered with vegetation.

On Monday^ June 4th^ about fifty of the party drove from
Great Malvern along the eastern side of the range to the Gullet
Pass (between Swinyard and Midsummer Hills). On the way
attention was drawn to the sharply defined eastern boundary of the
hills, and to the peculiar way in which the cwms end at their
faulted junction with the Trias.

In the quarry at the southern end of Swinyard Hill the struc-
ture termed " plagioclinal " by Dr. Callaway was discussed, and
the view was maintained that in pre-Cambrian times the western
midlands were occupied by an old mountain land, the folds of
which ran more or less transversely to the trend of the present
Malvern Hills, and that denudation had levelled the tract, which
later became a sea-floor, the component rocks of which, striking
across the meridian, had been covered unconformably by the
Cambrian sediments. The Archaean core of the present Malverns
might be regarded as a part of this old floor, thrust up in Car-
boniferous times and then denuded.

In a small quarry higher up the Gullet Pass the small faulted
strip of Hollybush quartzite and conglomerate was seen, and
specimens of Kutorgina phillipsii^ Holl., and an Obolella were
collected. Many pebbles of metamorphic quartzite, pink grano-
phyre, variously tinted rhyolites, etc., were obtained from the
conglomeritic layers, and it was argued that though these materials
bore a general resemblance to certain rocks of the present Malverns,
the balance of evidence indicated derivation from some other
source.

After lunching at the quarry the party proceeded to the ancient
camp at the top of Midsummer Hill, whence a magnificent view
of the surrounding country rewarded the climbers ; the Clee Hills,
the Lickey, the Cotswolds, May Hill, the Forest of Dean, and
many of the distant Welsh mountains being visible.

On the descent of the central depression of the hill, marking
the shattered infold of Cambrian and Silurian rocks, lack of time
prevented an extended search for debris of these rocks, but
fragments were picked up on the way, and the May Hill Sandstone
was seen in situ in the Hollybush Pass.

So6

EXCURSION TO MALVERN AND DISTRICT.

J
8

•2 = s <

•5
5

1 I |5

:! -:it •

EXCXmSION TO MALVERN AND DISTRICT.

507

s.w.

N.E.

Kolfybu9h SMmhtoM,
mOh UmutM§ (U

Fig. 5.— Sbction across the South-Western Part of
Raggedstone Hill.

a II FF ^

[Scale : 4^ inches=i mile.]
Fig. 6. — Section across Midsummer and Hollybush Hills.

FF. Faults. d.

h. Trias. c.

g. May Hill Sandstone. b.

f. Grey Shales (Cambrian). a.

e. Igneous rocks in Black Shales.

Black Shales (Cambrian).
Hollybush Sandstone.
Hollybush Quartzite.
Archaean.

S.6(?E.

F\!^.

\ N.6<fW.

[Scale : 4^ inchessi mile.]

Fig. 7.— Section of the Range along the Link of the
Malvern Tunnel.

rr.

Railway level.

Wenlock Shale.

F'F'.

Fault between Trias and Archaean.

Woolhope Limestone.

FF.

Faults.

Tarannon Shales.

Breccia.

May Hill Sandstone.

Trias.

Archaean.

.508 EXCURSION TO MALVERN AND DISTRICT.

Crossing the dyke in the HoUybush Sandstone, on the
northern slope of the Raggedstone, the party proceeded to the
picturesque district of White-leaved Oak. Here the chief features
of the area of Cambrian rocks were pointed out, and examples of
Spharophthalmus alaius^ Boeck, and Ctenopyge bisulcata^ PhiL, etc.,
were collected by many of the party from the inverted black Upper
Cambrian shales, but the small size of the exposures and their
overgrown condition made the discovery of fossils a matter of some
difficulty.

Owing to the lateness of the hour a short time only could be
devoted to the large quarry close to the village, but the junction
of the Hollybush Sandstone and Archaean was examined before
returning to Hollybush. Afterwards a visit was paid to the dyke
in the Hollybush Sandstone at the south-western comer of
Midsummer Hill.

On Tuesday, June sth, train was taken to Ledbury, where,

-after walking over the broken anticline of Ludlow rocks, an

examination was made of the Lower Ludlow Shales at the eastern

end of the tunnel. Many fossils, including Trilobites, Orthocera-

-tites, Brachiopods, and Corals were collected

The party then, retracing their steps, visited a quarry in the
Aymestry Limestone, the high westerly inclination of which, like
that of the passage beds from the Silurian into the Old Red Sand-
stone, illustrated the steep nature of the western side of the small
anticlines in this district.

At the station, owing to a recent cutting back of the western
end of the tunnel, the Ledbury Shales (passage beds) were once
more well revealed, and fine specimens of Lingula were obtained
from a green band at the eastern end of the cutting. The same
bed showed a striking example of soil-creep. After lunching in the
cutting, train was taken to Colwall, where at the western end of
the tunnel the Old Red Sandstone was seen faulted against the
Wenlock Shale. The latter formed an excellent collecting ground,
and the following fossils, with many others, were obtained : Plas-
mopora peialliformis^ Lonsd., Palceocyclus rugosus, E. and H.,
Pentamerus linguifer^ Sow., Orthis rigida^ Da v., Echinoencrinus
armaiuSy Forbes, Pisocrinus pillula^ De Kon. and Phacops
dawningia, Murch.

Upon leaving the cutting those members not obliged to return
home that day, concluded the day's work by a visit to the Upper
Ludlow Shales south of the station, where many characteristic
fossils were obtained.

On Wednesday, /uni 6th, starting from Ledbury Station by
brake, the Association paid a second visit to the southern Malvern
district. After passing through the picturesque old town of .Led-
bury, and through the wooded district of Eastnor, a halt was made
to examine the olivine-diabase between Bronsil Lodge and Fowlet
Farm. At the latter pl^e the party, leaving the brake, proceeded

EXCURSION TO MALVERN AND DISTRICT. 509

to Coal Hill Cottage, where numerous sills of diabase were seen
intercalated in the £>i^fyoHemashB\es. On the way to Howler's
Heath a recent cutting away of the turf, at the northern end of an
igneous boss south of Coal Hill, had exposed the ZHcfyonema-shaies
dipping in a south-easterly direction, and apparently indicating the
existence of one or more dislocations hitherto undetected in the
locality.

At Howler's Heath the May Hill Grits and Sandstones, and the
Haffield Breccia were examined, and after lunch a careful search
in the grey shales at the southern termination of Chase End Hill
resulted in the discovery of several specimens of Dlctyonema sociaie^
Salt., a fossil now less easily obtained than formerly at this locality.
In a cottage garden immediately east of Coal Hill the Dictyonema-
shales with sills of diabase were seen, like the same beds a little
farther south-east, to dip towards the hill.

Proceeding across the basaltic ridges through White-leaved
Oak, the party walked to the northern extremity of Chase End
Hill, where excavations made with the aid of a pick revealed the
oldest black shales yet detected in the Malvern district, and
numerous fragments of the peculiar dark grits interbedded with
these shales were unearthed. In the shales themselves specimens
of a form allied to Beyrichia angelim, Barr., were obtained.

The same species has been obtained by Prof. Lapworth in the
Stockingford Shales. In England, as in Scandinavia, the Beyrichias
are found beneath the zone of Spharophthalmus and its associates.
Many fragments of the shale were carried away to be split at
leisure; some of these subsequently furnished interesting speci-
mens of a new variety of Acroireta,

On the way back to Hollybush a few specimens of Hyalithus
{Serpuiites) fistula^ Holl., were collected from debris of the grey
Hollybush Sandstone at the north-western corner of Raggedstone
Hill.

Tea was provided at Hollybush, and then the party returned
by brake to Ledbury, where time was found to visit the old
church.

On Thursday^ /une yih^ train was taken to Colwall, and a
walk of about a mile brought the party to Upper Colwall, where
the inverted Wenlock Shale, Woolhope Limestone, and May Hill
Sandstone were seen in some excellent road exposures.
Numerous beautiful corals in the position of growth were detected
in the limestone, and specimens of Siricklandinia iens. Sow., Dino-
bolus davidsoni. Salt., and branching fucoids were obtained from
debris of the May Hill Sandstone. A sharp shower drove the
party to take shelter in Mr. Wickham's house, where the opportu-
nity was taken of examining his fine Silurian fossils.

Quarries showing the superposition of oolitic Wenlock Lime-
stone on Wenlock Shale were next visited. After collecting speci-
mens and lunching, the party proceeded down the dip-slope of the

5IO EXCURSION TO CATERHAM, GODSTONE, AND TILBURSTOW.

Wenlock Limestone to the Purlieu Lane, at the lower end of
which the Upper Ludlow beds with the usual fossils were seen
to be overlain by the Downton Sandstone, the two being probably
connected by transitional beds, though a small interruption in the
section prevents this being seen. From a carbonaceous layer in
the sandstone numerous imperfect specimens of Pachytheca were
collected.

It had been intended to examine the Silurian beds farther
north during the afternoon, but rain set in so heavily that a return
was made to Colwall, where the excursion concluded.

REFERENCES.
Geological Survey Map, Sheets 43 N.E., and 55 S.E. Price, 3s. each.

1848. J. Phillips. — •' Malvern and Abberley Hills.** Mem. GeoL Survey^

vol. ii, pt. I.
X865. H. B. HOLL. — " On the Geological 'Structure of the Malvern Hill*

and adjacent districts." Quart. Journ. GeoL Soc.^ vol. xxi, p. 72.
1872. R. I. MURCHISON.— " Siluria," 5th Edition.
1880. C. Callaway. — *' On a Second Pre-Cambrian Group in the Malvern

Hills." Quart Journ. Geol. Soc.^ vol. xxxvi, p. 536.
1884. W. S. Symonds— " Old Stones." New edition.
1887. F. RUTLEY.— " On the Rocks of the Malvern Hills." Quart. Journ,

Geol. Soc.^ vol. xliii, p. 481.

1887. C. Callaway. — " A Preliminary Inquiry into the Genesis of the

Crystalline Schists of the Malvern Hills." JHd.^ p. 525.

1888. J. J. H. Teall. — •* British Petrography/* pp. 245 and 269.

1893. C. Callaway. — "On the Origin of the Crystalline Schists of the
Malvern Hills." Quart, Jomn. Geol. Soc.y vol. xHx, p. 398.

1898. H. D. Acland. — *' On a Volcanic Series in the Malvern Hills, near

the Herefordshire Beacon." Quart. Journ. Geol. Soc.^ vol. liv, p. 556.

Malverns and of the adjacent district to the west." Quart. Jtmnu
Geol. Soc.y vol. Iv, p. 129.

1900. . — "On the Structure of a Portion of the Malvern and

Abberley Hills." Quart. Journ. GeoL Soc.y vol. Ivi, p. 138.

EXCURSION TO CATERHAM, GODSTONE, AND
TILBURSTOW.

Saturday, June i6th, 1900.

Director*. W. Whitaker, F.R.S. (President).

Excursion Secretary ; A. C. YoUNG, F.C.S.

The Geologists left London Bridge Station (S.E.R.) at 9.30, for
Caterham. They walked southward to the crest of the Chalk
escarpment at Upwood Scrubs, where a mass of the Blackheath
Pebble Beds overlying the Chalk was examined, and a fine
Proc. Geol. Assoc., Vol. XVI, Part 10, Novkmbir, 1900.]

EXCURSION lO CATERHAM, GODSTONE, AND TILBURSTOW. 511

view over the Lower Greensand tract obtained. The walk was
continued along a footpath down the escarpment to Godstone
Quarry, in Upper Greensand (fireslone, etc.). The underground
workings, down the dip northward, were noted and their many-
recorded water-levels at varying heights were alluded to ; but work
was going on that prevented the members from seeing these.
Instead of this, however, some old workings near Quarry Farm
were visited, and then a new working about a third of a mile east-
ward, where a good section was seen.

The members proceeded thence across the outcrop of the
Gault along the road to Godstone, stopping at the northern part
of the village, to see a sand-pit in the Folkestone Beds. This was
formerly carried on as an underground working (for the lower bed
of sand), but has now been opened up, the upper bed of sand
being also worked. The walk was then continued, through the
village of Godstone, to the pits of Tilburstow, which are more
than a third of a mile long, and made simply to get the chert at
the bottom for road-metal. A very large area has been worked
over the tract to the east, now a plantation. At one part a little
of the Folkestone Beds (sand) is touched. The whole of the
Sandgate Beds is passed through (clayey and with green sand).
The chert is classed with the Hythe Beds by the Geological
Survey. A fine landslip was seen in part of the pit. The excur-
sion was continued eastward by way of a cutting on the road down
Tilburstow Hill in the sands of the Hythe Beds, to the faulted
mass in which the chert-beds are again shown on the western side
of the road.

The return journey was made down the dip-slope of Tilbur-
stow Common ( Hythe Beds), across the fields to Tandridge, and
through Tandridge Park (dip-slope of the Folkestone Beds) to
Oxted, a walk that gave constant, opportunities of seeing the
beautiful and varied scenery of the Lower Greensand of Surrey.

REFERENCES.

Ordnance Maps, 6-inch, Surrey, Sheets 27, 28 and 35. One-inch, New

Series, Sheet 286.
Geological Survey Map, Sheet 6.

1866. Meyer, C. J. A. — " Notes on the Correlation of the Cretaceous Rocks-

of the South East and West of England," Geol, Afag,, vol. iii.
1872. Whitaker.— " Geology of the London Basin," pp 24, 257.
187s. ToPLEY.— " Geology of the Weald,** pp. 120, 121, 153, 154, 234, 371.
1888. BOULGER, G. S. — Excursion to Caterham, etc. Proc, Gtoi, Assoc.^ vol.

X, p. 496.
1895. Leighton, T. — "The Lower Greensand ... of East Surrey.'*

Quart, Jouru, Geol, Soc.y vol. li, p. loi.
1895. .— " Excursion to Tilburstow Hill." Proc. Geol. Assoc.^

vol. xiv, p. 191.

512

EXCURSION TO GUILDFORD.

Saturday, June 23RD, 1900.

Director-, A. K. Coomara-Swamy, F.G.S.

Excursion Sicniary : A. C. YoUNG, P'.C.S

(^Report by Thk DIRECTOR.)

The party reached Guildford at 2.20, and proceeded, by kind
permission of Mr. Mitchell, to the more westerly of the Guild-
ford Park Potteries pits. The section is chiefly in mottled clay,
but on the north side this is overlain by a brown shelly bed, with
Cyrena, Ostrea, and Melania inquinaia. This shelly bed is
evidently the same as that mentioned by Mr. Whitaker as forming
the top of the Woolwich and Reading Series in the railway cutting.
The section visited is the most westerly exposure of the shelly
beds. The lower mottled clay contains some concretions of
the nature of "race," remarkable for their very large size and
irregular forms.

Analyses of the "race" made by Mr. A. C. Young give the
following percentages :

Carbonate of lime 64*5

Clay 17-5

Very fine sand 180

Crossing Guildford Gap the large quarries in Quarry Street
were visited ; in these the Upper and Middle Chalk are well
exposed. In the upper pit the former is very massive. In the
lower pit (Middle Chalk), Mr. Whitaker called attention to the
fibrous markings found in the chalk, and said that they probably
represented pseudomorphs of calcite after aragonite, and were not
of the nature of slickensides.

Taking the field path to the Chantries, and thus crossing
the Upper Greensand and Gault, the Folkestone Beds of the
Lower Greensand were seen in a small quarry opened on the
north slope of the Chantries; and a few yards farther on the
party turned north again up the short lane leading to the Warren
Farm Quarry. An exposure of Upper Greensand chert was
noticed in the lane. The quarry itself shows grey chalk and
Chalk Marl, much shattered and inclined at a very high angle,
the disturbance being due to a local fault. The long narrow
quarry seems to follow the strike of the beds. Pecten beaveri and
Ammonites rhotomagensis were found.

Crossing the CJhantries by kind permission of the proprietor,
the escarpment made by the Bargate Stone was reached, and
from this position a fine view was obtained of the Lower Green-
sand district and the Weald beyond. The Director pointed out
Proc. Geol. Assoc, Vol. XVI, Part 10, November, 1900.]

EXCURSION TO SILCHESTER. 515

the Peasemarsh anticline, which soon dies away to the east, and
the wide outcrop of Atherfield Clay in the East Shalford district.

The party descended the slope and visited the brickyard near
the railway. Here a few feet of Atherfield Clay is seen to be
overlain by Drift. In this district the lower part of the Ather-^
field Clay contains a band of very fossiliferous nodules. These
are not seen in the brickyard, but a few were obtained from the
bed of the Tillingbourne, near by, and exhibited to the members.
Thetis minor. Sow., Area raulini, Leym, Pema, and many other
fossils could be seen in them.

The party then returned to Guildford, where tea was obtained.
In the station yard a vote of thanks was accorded to the
Director, who replied, and the party returned to town by the 7.41
train.

REFERENCES.

Geological Survey Map, Sheet 8 rDrift Edition).
Ordnance Survey Map, one inch, New Series, Sheet 285.

1868. C. J. A. Meykr. — •* Lower Greensand of Godalmingf."

1872. W. Whitakkr. — " Geology of the London Basin," Mtm. Gtoi. Survey,

1875. W. TOPLKV.— "The Geology of the Weald." Afem. Gtol, Survey,

1876. Ch. Barrois.— " Terrain Cretac^ de TAngleterre.'*

1884. R. A. Godwin- Austen and W, Whitaker. — *' New Railway Cutting^

at Guildford." Quart, Journ. Geoi. Soc., vol. xl, pp. 599—613.
1891. " Record of Excursions," pp. 93, 97, 98, 100.

EXCURSION TO SILCHESTER.

Saturday, June 30TH, 1900.

Director: J. H. Blake, Assoc. M.Inst. C.E., F.G.S.

Excursion Secretary: A. C. YouNG, F.G.S.
(^Report by Thk DIRECTOR.)

The members assembled at Reading Station at 12.49 p.m., and
proceeded to the Reading Museum and examined the Romano-
British collection from Silchester. Mr. Colyer, the assistant-
curator, pointed out many of the most interesting relics, amongst
them being a considerable number of Roman silver and bronze
coins, ranging from B.C. 39 to a.d. 423. After a vote of thanks
to Mr. Colyer, proposed by the President, the members returned
to the station and entrained for Mortimer, where they arrived
about 2 p m. They then walked nearly two miles in a south-
westerly direction to a projecting spur of plateau -gravel westward
of Brocas Land Farm, where a fine view of the surrounding
country was obtained. The Director briefly explained the
Proc. Gkol. Assoc., Vol. XVI, Part 10, November, 1900.]

514 EXCURSION TO SILCHESTER.

:geological structure of the district, and stated that the plateau-
gravel (Southern Drift) rested upon Lower Bagshot Beds over-
lying London Clay. But what he particularly drew attention to,
and wished to impress upon them, was the large amount of
denudation that had taken place since the deposition of the
plateau-gravels. These occupied all the highest ground in the
district, and often occurred as isolated patches on outliers of the
Bagshot Beds, one of which he pointed out three-quarters of a
mile to the east of Silchester, where the plateau-gravel was at the
same level as that at Silchester, namely, 300 ft. above sea-level,
with a valley intervening more than 100 ft. in depth.

The members, who were here joined by the cyclists with
Mr. Monckton, then resumed their walk. During their descent
into the valley separating them from Silchester, attention was
drawn to an exposure of Lower Bagshot Beds in the road-cutting ;
and to the junction of the Bagshot Beds with the London Clay
on the opposite side of the valley, where a spring was thrown out

On arrival at the Amphitheatre, Mr. Mill Stephenson — in
charge of the Silchester excavations for the Society of Antiquaries
— conducted the party first into the Amphitheatre, then to the
north wall of the Roman city, and afterwards through the Manor
Farm to where the excavations were in progress, south-east of the
North Gate. Here the foundations of houses were exposed, with
tesselated pavements and mosaic floors, hypocausts, etc., and
rubbish-pits (about 6 ft. in depth) from which so many relics
had been obtained. Four special excavations had been made
by Mr. Mill Stephenson to show the junction of the plateau-
gravel with the underlying Lower Bagshot Beds. The deepest
well that had been explored was 32 ft. in depth. After an
inspection of the relics that had been found this year, the Forum
{now much grown over) was visited and described by Mr. Mill
Stephenson.

Leaving the City by the West Gate, the members proceeded
to a large gravel- pit on Silchester Common, which showed a section
6 ft. in thickness, of pebbly and subangular flint-gravel, charac-
teristic both in constituents and thickness of the plateau-gravel
{Southern Drift) of this district.

Called upon by the President to give views as to the gravel
before them, Mr. Monckton remarked that they were on a plateau
a little more than 300 ft. above the sea, capped with what he had
termed the Silchester type of Southern Drift.* He looked upon
all these gravels as river-gravels, the composition depending upon
the various rocks to be found in the drainage-area of the various
streams. This gravel contained no Lower Greensand debris and no
Bunter pebbles, and was evidently deposited by a river draining
a Chalk and Tertiary country, much the same as the present
Kennet-Loddon drainage-area.

* Quart, Joum. GeoL Sod vol. xlviii, 1892 (Map on p. 38).

EXCURSION TO SILCHESTER. 515

The next gravel-capped plateaux to the east, Spencerwood
Common, Heckfield Heath, etc., were capped by gravel containing
an abundance of fragments from the Hythe Beds of the Lower
<^reensand, and may perhaps be looked upon as gravel of an old
edition of the River Blackwater. The present Blackwater does
not, however, drain any Lower Greensand country ; it is
separated from the nearest outcrop of that formation by the River
Wey, and the speaker suggested that these gravels show that the
Blackwater used to have a great drainage area to the south or
south-east which has now been acquired by the River Wey, just
as much old Thames drainage-area has been acquired by the
River Severn.

The debris of the Hythe Beds, so abundant in the gravel of
Spencerwood Common, has not only been brought across the
present course of the Wey, but also across the present course of
the Loddon, and this looks as though the Blackwater used to join
the Loddon a little farther west than now. Mr. Monckton
suggested that Spencerwood Common was very probably the
actual point of junction of the two streams.

The Director then exhibited the new Geological Survey Maps
of the district, one with Drift and the other without, and explained
how very different from the present the Conditions and physical
features of the country must have been when the extensive spreads
of plateau-gravels were deposited. He also referred to the distri-
bution of the Northern Drift, characterised by its numerous large
rounded quartzites, in contradistinction to that of the Southern
Drift, which did not contain any. Pointing to the hills visible in
the distance, he stated they were the abrupt uprise of the Chalk
on the south side of the London Basin,

Tea was partaken of at the Crown Inn, when a cordial vote
of thanks, proposed by the President, was accorded to the
Director, to Mr. Mill Stephenson, and to the Society of Antiquaries,

The party returned by a different route to Mortimer Station,
and in Wall J^ne inspected another section (6 ft. in thickness) of
plateau-gravel, which, though a continuation of the same spread
of gravel, showed a much more stratified appearance than that in
the pit on Silchester Common.

Reading was reached at 7.15 p.m., when some of the members
visited the Abbey ruins and Forbury Gardens before leaving by the
8.20 p.m. train.

After tea those members who had brought cycles accompanied
Mr. Monckton to Heckfield Heath, where they visited a pit in
what he called old Blackwater gravel, now 270 feet above the sea.
The abundance of fragments from the Hythe Beds was noticed.

Mr. Monckton remarked that other flats occur at lower levels

5l6 EXCURSION TO KETTERING AND THRAPSTON.

and illustrate the remarks as to step terraces which he made
at Kingston Hill on April 28th (see p. 444). He considered
that these flats marked pauses in the process of elevation of the
land. The gravel at Heckfield was seen to be much more
clearly stratified than that at Silchester Common.

REFERENCES.

Geological Survey Map, One-inch (Drift Edition), Sheet 268.

Ordnance Survey Map, Six-inch, Sheet 44, Berkshire, and Sheet 4, Hampshire.

1872. W. Whitaker.— " The Geology of the London Basin." Mgm, Ged.

Surve); vol. iv, pp. 313, 314.
1890. Sir J. Prestwich.— " On the Relation of the Westlcton Shingle to

other Pre-Glacial Drifts in the Thames Basin, and on a Southern

Drift. . . . *' Quart. Journ. Geoi, Sbc.^ vol. xlvi, pp. 161, 162, etc
1892. Horace W. Monckton — ^"On the Gravels South of the Thames

from Guildford to Newbury." Quart. Jomrn. Geo/, Sbc., vol. xlviii,

pp. 29-47.

EXCURSION TO KETTERING AND THRAPSTON.

Saturday, July 7th, 1900.

Directors: Prof. J. F. Blake, M.A. and Beeby
Thompson, F.G.S.

Excursion Stcntary : W. P. D. StebbinG.
{Report by ].Y. BlaKE.)

The party from London met some of the members from
Northampton, including one of the Directors, at Kettering Station,
whence they walked to the brickyard on the Thrapston Road.
Here is seen an apparent junction of the upper beds of the Lias
with the overlying Northampton Sands, or Ironstone ; but it was
pointed out by Mr. Thompson that the upper hard beds were
wont to slip over the soft unctuous clay, particularly on the slopes
of hills, and that in all probability some of the highest beds of
the Lias, here really existing, were thus concealed. He pointed
out, some ten feet below the apparent summit, a line of white
weathering nodules, often coated with encrusting organisms as
though they had long lain exposed on the sea bottom, above
which there was a different fauna to that in the beds below —
a fact easily verified by the members. Hence he regarded this
line as the palseontological summit of the Lias proper, the beds
above being the A, yurensis-heds, which are continued into the
base of the ironstone.

From this brickyard the members had a walk of about four miles
Prog. Geol. Assoc, Vol. XVI, Part 10, November, 1900.]

EXCURSION TO KETTERING AND THRAPSTON. 517

to Cranford St John, where, after lunch they examined a deserted
•quarry in the Great Oolite limestone. It was here pointed out
that we were crossing the Lower Oolites on the line of their
feeblest development The whole of the Inferior Oolite is
represented by a few feet of Northampton Ironstone, and a few
more of Estuarine beds, the Upper and Lower divisions here
becoming one continuous series, on account of the absence of
the Lincolnshire Limestone, which only commences a little north
of this. The Great Oolite itself here consists also of a few com-
paratively thin beds, and they are consequently crowded with
fossils, of which the members made a good collection. These
included a Terebratula very like T. intermedia^ and a Rhynchonella
considered by Mr. J. F. Walker to be new.

From this point exposures were numerous, large and good«
One newly worked showed both divisions of the Estuarines
lying on the Ironstone in a rather disturbed manner, and
another about 3 miles from Thrapston, on the south side of the
road, showed the complete succession of Ironstone (just seen),
Estuarine, Oolite, and Oolite clay (just seen).

The next working was an exceptionally fine one of the
Cornbrash, which it was the primary object of the excursion to
see. Here was exposed a very long section showing at the top
Boulder Clay, to a large extent derived from the neighbouring
Oxford Clay. Next came most characteristic Cornbrash in several
bands, all highly fossiliferous, about 5 feet. Then about 12 feet of
blue-black clay called Great Oolite clay, and at the base 1 1 feet of
•Great Oolite limestone, for which the opening is made. The
members of the party had thus been able to see during the day
the junctions of the five divisions of the rocks between the Lias
and the Oxford Clay, and to verify the thickness of four of these
divisions. The spoil heaps, in which the Cornbrash fossils are
unmixed with those of the Oolite, being thrown in a different place,
provided a good harvest of fossils to collectors.

This working is opposite the Islip iron furnaces, a little more
than a mile from Thrapston, whither the members then adjourned
for tea, after which some few were able to see the old Thrapston
workings close to the Midland Railway Station whence so many
Polyzoa have been obtained, and the party finally took train vi&
Kettering to London.

REFERENCES.

Geological Survey Map, Sheet 52, N.W.

Ordnance Survey Maps, New Series, Sheets 171 and 186.

1875. JUDD, J. W.— •* Geology of Rutland." Mim. Geoi. Survty.
1883-4. Vine, G. R.— Rep. Brit. Assoc. (3rd and 4th Reports of the Committee
on Fossil Polyzoa).

1887. . — Journal Northamptonshire Nat. Hist.Soc.,voLiv,p. 2oa.

1894. Woodward, H. B.— " The Lower Oolitic Rocks of England." Mim,
Geol, Survty,
Proc. Gsol. Assoc., Vol. XVI, Part 10, November, 1900. J 39

Si«

EXCURSION TO PURLEY, KENLEY, AND
WHYTELEAFE.

Saturday, July 14TH, 1900.

Directors: The President and G. E. Diblky, F.G.S.

Excursion Stcrttarv : W. P. D. Stebbing, F.G.S.
(^Rtport by G. E. DiBLEY.)

The members arrived at Purley Oaks Station at 2.20 p.m.^
and proceeded to Haling Pit. The Director stated that the chalk
is worked in the base of the Micraster cor-anguinum-zone, as
described in the Proceedings, vol. xvi, p. 490, and referred to
the absence of fossils characteristic of the upper part of the zone.

The large pits at Purley Junction were next visited, where the
lithological character of the Chalk which marks the zone of
Micraster cor-testudinarium in the London area was noted.
Near Purley Station the President drew attention to some large,
rounded masses of Woolwich and Reading conglomerate or
" pudding stone," and stated that they are a prominent feature in
the Caterham Valley ; they extend as far as Croydon and could be
traced in the various gravel-pits along the course of the Croydon
Bourne, from the Kenley Waterworks to Purley Station.

At Kenley several fossils were procured from the Rose and
Crown pit, including Terebratulina striata and a Nautilus in
addition to the characteristic zone-fossils. Tea was very kindly
provided by the Rev. T. Griffiths, M.A.. Votes of thanks, pro-
posed by the President and, Mr. E. T. Newton to Mr. and Mrs.
Griffiths for their repeated acts of kindness to the Association^
were accorded by acclamation.

After a vote of thanks to the Director had been duly acknow-
ledged, a move was made to the Whyteleafe Lime Works, where
the characteristic fossils of the zone of Terebratulina gracilis were
obtained.

REFERENCES.

Geological Survey Map, Sheets 6 and 8.

Ordnance Survey Map, New Series, Sheets 270, 286.

1857. GODWIN-AUSTKN, R. A. C. — "On a Granite-Boulder in the White
Chalk near Croydon." Quart. Journ. GioL Soc.^ vol. xiv., p. 253.

1870. Evans, C— **On Some Sections of Chalk between Croydon and
Oxted." Geol. Assoc. Sei>ar ate publication ^ price td.

1887. Woodward, H. B. — " Geology of England and Wales " (2nd Edition),.
pp. 403, 41S.
See also " Record of Excursions," pp. 80-82.

Proc. Geol, Assoc, Vol. XVI, Part 10, November, 1900.]

519

EXCURSION TO AVINCHFIELD AND HOOK.
Saturday, July 2ist, 1900.

Directors : P. L. Sclater, Ph.D., F.R.S., and
H. W. MONCKTON, V.P.G.S.

Excursiom Secrttary : W. P. D. Stkbbing, F.G.S.
(^Report by H. W. MONCKTON.)

The party assembled at Hook Station and walked eastwards
along the main line of the London and South Western Railway
to Winchfield.

For the first i^^ miles the railway is carried on an embank-
ment, the country being London Clay and the Alluvium of the
Whitewater. A little south of the line there is the extensive
gravel-flat of Bartley Heath. The gravel consists of material
from the Chalk country to the south. The level is 247 ft.
above the sea.

Shortly after crossing the Whitewater, the Bagshots come in
and cause a rise of the ground, the embankment giving place to
a shallow cutting.* A halt was made at a place where a bridge
crosses the line, and the Directors gave an account of the
geography and geology of the district. It was explained that
the object of the excursion was to visit the fine section at
Shapley Heath, made for the purpose of widening the line. The
section was on the south of the railway.

Mr. Monckton remarked that the section extended from
the Barton Beds (Upper Bagshot), of which there were some
15 ft, through the whole of the Bracklesham (Middle Bagshot),
into the Bagshot (Lower Bagshot). He drew a comparison
between it and other railway cuttings which had passed through
the same formations, and in particular Goldsworthy, described by
Prestwich in 1847 {Q.J* G, 5., vol. iii, p. 382). The cutting on
the Ascot-Bagshot line described by Mr. W. H. Herries, in 1881
{Geol. Mag,^ April, 1881), and that near Wellington College on
the South Eastern Railway described by himself in 1883. XQ^J.
G, S,, vol. xxxix, p. 350).

Proceeding along the line the light-coloured current-bedded
sand of the Bagshots was seen at the western end of the Shapley
Heath Cutting. Above it were laminated clays, forming, as Mr.
Monckton said, the bottom of the Bracklesham — the junction
being well seen. There had been, he added, some discussion as
to the exact point at which the division between Bracklesham and

* Note.— The bottom of the Bagshot Beds is not seen to the east of Hook, but it is well
shown in the cutting on the west of the station. The top of the London Clay is sandy.—
H. W. M., Sept. 36th, 1900.

Proc. Geol. Assoc., Vol. XVI, Part 10, November, 1900.]

520 EXCURSION TO WINCHFIELD AND HOOK.

Bagshot (/.^., between Middle and Lower Bagshot), should be
drawn, but the importance of that separation had been much
reduced by the discovery of abundant casts of marine shells some
20 ft. down in the yellow sands of the Bagshot (Lower Bagshot), at
Woking. These laminated clays are very constant at the bottom
of the Bracklesham (Middle Bagshot), and form the lower of the
two brick-clays of that Series in the district.

Some part of the cutting had been sloped at the time of the
excursion, but Mr. Clement Reid, F.R.S., who saw that part when
fresh, had kindly furnished the following note : —

" A well at the western end of this cutting was sunk 28 feet into
the Bagshot Sand, />., about 25 feet below the level of the rails.

"Exactly opposite the western edge of Oldman Copse the
cutting is shallow and shows :

Feet

BRACKLESHAM { ^"rrj^f C^^str^S ^'!^^^^^^^^ -

f Fine white, much false-bedded, sand

Bagshot . < with clay-pebbles (dug to below rail- • 17
( level) )

" On the west side of Shapley Tunnel, the upper part of the
cutting shows gravel resting irregularly on buff and yellow loamy
sand. In the middle of this cutting the gravel is thin and the
section is :

Feet,

Gravel thin

Brown and yellow loam 15

Laminated blue sandy loam ... ... ... ... 18

Glauconitic greensand —

" About 100 yards east of Shapley Tunnel [now removed and
replaced by a bridge], a landslip showed white sand overlying
the dark-grey sandy laminated loam, which occupies the lower
20 feet of the cutting. Above this sand were more loams like
those exposed farther east. At the top of the cutting there is a
little gravel.

" On the west side of the Winchfield Station bridge, the green
loam becomes darker, and as the cutting deepens westward sandy
loams come on above to a thickness of about 25 feet. Still
following the beds westward, the lower deposits become
un weathered and greener."

Mr. Monckton drew special attention to the green bed which
occurs with great constancy between the brick-making clays, and
is the fossiliferous bed in this district.

The characteristic shells usually were Cardita pianicosia^ Lam.,
and Corbula gallica^ Lam., but neither of them had been found
here, and the only mollusca found were casts of a spiral shell,
probably a Turritella. A considerable collection of fish remains
was found, and the following have been kindly determined by
Mr. E. T. Newton, F.R.S.

excursion to winchfield and hook. $21

Fish from Shapley Heath, Winchfield, Bracklesham
Series (Middle Bagshot).

Teeth,
Odantaspis macroia^ Ag. (3 specimens).

„ eleganSy Ag. (2 specimens).

„ cuspidaia^ Ag. (3 specimens).

„ acutissimaj Ag. (i specimen).

Lamna vincenti^ Winkl. (3 specimens).
Galeocerdo minor ^ Ag. (2 specimens).
j£tobatis or Myiiobaiis (probably both) (8 specimens).

Vertebra,
Teleostean vertebra (2 specimens).

Fin Spine,
Ccelorhynchus rectus ^ Ag. (i specimen).

Also eight specimens of teeth of Odontaspis, not well enough
preserved for the species to be determined.

Ascending the cutting at the bridge, Dr. Sclater led the way
to the top of the hill, 319 ft O.D., from which a very fine view
was obtained. He drew attention to the chief features of the
country, and in particular to the Tertiary outliers at Horsedown
Common and Well. At the former spot the Reading Beds are
capped by London Clay, which rises to a height of over 500 ft.
above the sea.

Returning to the railway the members descended the side of
the cutting on the east of the bridge, and Mr. Monckton
explained his version of the succession.

There was a cap of gravel (Southern Drift) mainly flints, but
with a few fragments from the Hythe Beds. Then there were
about 15 ft. of yellow sand with a pebble-bed at the bottom —
Barton (Upper Bagshot). The top of the Bracklesham (Middle
Bagshot) was clayey, and in it were several irregular lines of
pebbles. Below there was a light-coloured sand with laminae of
whitish clay; in some places the sand and in others the clay
predominating. Then there was a well-marked water-line, the
top of a dark-coloured clayey bed. The above beds, with a
thickness of about 20 ft., forming the upper brick-making beds of
the Bracklesham of this district. The green bed, with fossils,
probably occurs at the bottom of the cutting, but was hidden by
slips at the time of the excursion.

After completing their examination of the cutting, the members
walked to the Beauclerk Arms Hotel, where tea was provided.
After tea, on the motion of the President, a vote of thanks to the
Directors was passed, and a vote of thanks was also accorded to
the Representative of the London and South-Western Railway,

522 EXCURSION TO CUTTING S. OF GROVE PARK STATION, S.E.R.

who had kindly accompanied the party during the afternoon, and
had given much assistance and information.

After tea a visit was paid to a brickfield on the west of the road,
a little south of Winchfield Station, where the Bracklesham clays
are worked, and this concluded the work of the afternoon.

REFERENCES.
Geological Survey Map, Sheet 284, New Series^ price 35.

1847. Prkstwich, J.— •' On the Structure and Age of the Bagshot Sands."

Quart, Joum. Geol. Soc.^ vol. iii, p. 378.
1872. Whitakkr, W.— " Geology of the London Basin." Mem, Geol, Survey^
vol. iv.

EXCURSION TO THE RAILWAY CUTTING SOUTH
OF GROVE PARK STATION, S.E.R.

Saturday, July 28th, 1900.

Director: T. V. Holmes, F.G.S.

Excursion Secretary: A. C. YouNG, F.C.S.
(^Report by The DIRECTOR.)

The object of this excursion was to visit the cutting north of the
tunnel between Grove Park and Chiselhurst stations on the
S.E.R. main line.

Alighting at Grove Park Station, the party entered the cutting,
permission having been obtained for that purpose. Before
descending to examine the details, the Director made a few
general remarks on the slight amount and varying direction of the
dip of the beds within a radius of a mile or two from the spot
on which they were standing. In the cutting, the dip, he said,
coincided so perfectly in direction with that of the line thence to
Grove Park Station, that the section given by Mr. Whitaker of
the eastern side as seen in 1865, showed accurately what could
now be seen on the western. (See Whitaker, " Geology of
London," etc., vol. i, 1889, p. 226, Fig. 41.) But while the dip where
they were standing was to the north-west, close to and west of the
entrance of the tunnel it became southerly ; and in Rockpit
Wood, at the southern, or Chiselhurst, end of the tunnel, the
dip was northerly. As to the details of the Tertiary beds in the
immediate neighbourhood, the fullest information was that
furnished by a boring at the new workhouse at Grove Park, the
details of which had been kindly sent to him by Mr. T. Dinwiddy,
architect of the buildings. This borehole was made between
Dec. 20th, 1898, and Jan. 21st, 1899.

PROC. Geol. Assoc, Vol. XVI, Part 10, November, 1900.]

EXCX7RSION TO CUTTING S. OF GROVE PARK STATION, S.E.R. 523

BOREHOLE AT NEW WORKHOUSE. GROVE PARK.

Dqx>sit made
by a small brook.

Oldhaven Beds ?
22 ft.

Woolwich and

Reading Beds ?

47 ft.

Thanet Sand
S3 ft.

i Subsoil

I Ballast

London Clay

Black pebbles and water

Clay and shells

Green sand and water

Hard shells

Green blowing sand

, Clay and shells

j Blowing sand and water

I Clay and shells

^ Very hard clay and shells

Coloured clay

Green sand, pebbles, and water ...

^ Black sandf pebbles, and water ...

' Very hard grey sand, rock, and

water

Live grey sand and water

Flints

Into chalk

ft. in.

2 O

3
13

2
1

2
10

3
6

9
10
10

°r^.

18 o

40 o

87 o

140 o
243 o

Entering the cutting towards its northern end, where the
London Clay only could be seen, the party made its way south-
wards towards the mouth of the tunnel Between the northern
end of the cutting and the bridge nearer the tunnel (by which a
road crosses the railway) the London Clay, with a pebble band
from Sin. to iSin. thick at its base, and a few feet of Oldhaven
sand with scattered pebbles at the bottom of the cutting, were
very cleariy seen. Under the bridge the pebbly base of the
Oldhaven Beds, containing shells, appeared. A few yards south
of the bridge the outcrop of the London Clay with its basement
bed was well exposed. On coming to the cutting west of the
mouth of the tunnel, it was found that there the London Clay,
with a pebble band at its base about 3ft thick, was again
visible, the dip being very slight in amount, but southerly in
direction. There is, therefore, either a roll over of the beds or a
£ault between the bridge and the mouth of the tunnel.

At one spot north of the bridge a little patch of false-bedded
sand appeared in the London Clay near its base. Crystals of
selenite were abundant in the London Clay. In Mr. Whitaker's
section of the more easterly side of this cutting, two small but
sharp turns in the basement pebble-bed of the London Clay may
be seen. The section being clearer than in 1865, these two
sharp turns appeared to be two small reversed faults dislocating
the pebble-bed to the extent of a foot or perhaps a trifle more,
their course not being traceable in the clay above or in the sand
below. After examining the beautifully clear sections the party
dispersed.

524

EXCURSION TO NETLEY HEATH AND
NEWLANDS CORNER.

Saturday, August iith, 1900.

Directcr: W. P. D. Stebbing, FG.S.

Excursion Secrttary : H. A. HiNTON, B.Sc, F.G.S.
(^Report by THE DIRECTOR.)

The chief object of the excursion was to examine the gravely
sands, and ironstone at Netley Heath, to prove the fossiliferous
character of the ironstone and to show the similarity of the beds
to those occurring at points farther eastward on the North Downs.

The party assembled at Gomshall Station, and walked by way
of Colekitchen Farm to Netley Heath, traversing the outcrop of
the Gault and Upper Greensand.

A fine section in the Folkestone Beds was seen outside the
station, and another section at the top of these sands was
examined ; also road sections in the Gault, Upper Greensand, and
base of the Middle Chalk were noted in passing.

Netley Heath consists of a tract of ground with a northerly
slope, mainly covered with heather. The sands and ironstones
are shown by a red colour on Sheet 8 of the Geological Survey
Map, and extend from a level of about 600 feet O.D. almost at
the top of the North Downs (as at Headley Heath) to a level of
about 570 feet O.D.

This patch of sand and ironstone forms one of a series which
is found along the top of the North Downs from Netley Heath to
Paddlesworth, north of Folkestone. The fossiliferous pipes at
Lenham, range from 500 to 620 feet O.D., and the sands on
Headley Heath occur at 628 feet O.D. But although of a far
more recent age than the Eocene outliers, which are often in close
proximity, these sands occur at much the same level or even
below them. This is undoubtedly due to their porous nature,
which allows water to pass through and dissolve the chalk below.

The attention of geologists was first drawn to this series by
Prestwich in 1857 {Quart fourn, Geol. Soc, vol. xiv, p. 322), and
details of all the patches will be found in our President *s Memoir
on the London Basin (Whitaker, Mem, Geo/. Survey, vol. iv, i872>

PP- 339-342).

As early as 1854 fossils were found in one of these
patches at Lenham, in Kent, but their evidence as to the age of
the sands was considered doubtful, although Prestwich assigned
them to the Crag. In 1886 Mr. Clement Reid made a careful
investigation of the deposit at Lenham and its fossils, and
satisfactorily proved the depo?»t to be of Pliocene age (Nature^
Proc. Geol. Assoc, Vol. XVI, Part 10, November, 1900.]

EXCURSION TO NETLEY HEATH AND NEWLANDS CORNER. 525

voL xxxiv, p. 341). A full account of Mr. Reid's work will be
found in his Memoir on the Pliocene Deposits of Great Britain,
1890 (Mem. GtoL Survey), At page 48 he remarks : " Westward,,
towards Merstham and Guildford, some of the outliers mapped
by the Survey may really be Pliocene as suggested by Prof.
Prestwich, but at present there is such an entire absence of
positive evidence in favour of this view that it is needless to
describe them."

This sentence is quoted to show the great interest which
attaches to the imperfect fossils found now apparently for the first
time at Netley Heath. The patch in which they are found is not
mapped as Eocene or Pliocene, but as of doubtful age The
fossils are in the form of casts in af erruginous sandy grit with
occasional flint pebbles. The grit much resembles the ferruginous
sandstone of the Folkestone Beds, but the presence of the flint
pebbles is sufficient distinction.

Fragments of fossils referable to the genera Modiola^ and
possibly Cyprina^ were found by members during the excursion,
and fragments of Nassa, Trochus, Cardium, Peciunculus, Tellina^
and Thracia have since been found, but in such a poor state of
preservation that they cannot be specifically determined. These
genera indicate beds of a marine origin, and although they do not
enable us to correlate these deposits with those at Lenham with
certainty, I am inclined to think that the beds will prove to be
of the same age. All the above genera except Modiola have been
found at Lenham, where, on the visit of the (geologists' Association
in 1892, 31 species of fossils belonging to 27 genera were obtained.

It was remarked by members who had visited Lenham, that
the mode of occurence of the fossils and the appearance of the
matrix greatly resemble the conditions obtaining at Lenham.

The following sections were visited :

1. A sand-pit on the east of a road from Gomshall to East

Horsley, showing about i o feet of yellow and bleached sand ;
above the sand are some patches of mottled clay and gravel
consisting almost wholly of rolled fragments of chert and
ironstone from the Ix)wer Greensand. Level, about 570 feet.

2. A small pit about 5 feet deep, at a level of rather over 60a

feet ; the section shows highly ferruginous yellow sand with
a few small pebbles and much concretionary iron ore, with
chert and patches of rolled flints above. The fossils came
from this pit.

3. A sand-pit half-a-mile west of the first pit, showing about 12

feet of yellow sand with a few small pebbles, and in one
place a patch of small pebbles above the sand. Level
about 600 feet

There is a fourth section on the Heath rather lower than the
others, which was not visited. This pit contains a mixture of

526 LONG EXCURSION TO KESWICK

sand and rolled flints of all sizes, and is exactly similar to one seen
on Headley Heath in 1895, ^^ about the same level.

The Director remarked that the difference in these three
sections on Netley Heath is surprising considering their short
distance apart ; but if we suppose that they were formed on a
submerged reef away from the coast line — which is Mr. Reid's
theory — those portions of the reef near the sea-level would be most
affected by the action of the sea, which would prevent shells from
accumulating on those portions, and which would have a rounding
action upon any loose stones; a state of things which might explain
section i.

Leaving Netley Heath, the members followed the track along
the top of the North Downs to Newlands Comer, and visited the
extensive gravel workings there at about 500 feet O.D. The
gravel, which otherwise is similar to that which occurs in most of
the sections on Headley Heath, is characterised by the large size
of the flints of which it is chiefly composed. Mr. Mbnckton's
explanation of it is that it is probably a very old river gravel, but
no doubt newer than the sands and ironstone of Netley Heath.

Leaving these sections, the party made their way to Chilworth
for tea. After the Director's reply to a most cordial vote of thanks,
the geologists returned by the 7.56 train to Lc>ndon.

REFERENCES.

Gcelogical Survey Map, Sheet 8 (Drift Ediiioii).
Oidnance Survey Map, New Series, Sheet 285, is.

1862. W. Whitaker.— "On the Western End of the London Basin, etc.,"

Quart. Journ, Geol. Soc.^ vol. xviii, p. 273.
1887. H. H. French. — "Excursion to Gomshall, Netley Heath and

Clandon," Proc. Geol, Assoc., vol. x, p. 182.

LONG EXCURSION TO KESWICK.
Monday, August 20th, to Saturday, August 25th, 1900.
Director-. John E. Mark, M.A., F.R.S., F.G.S.

Excursion Secretary : FREDERICK Meeson.

(^Report hv The Director.)

[PLATES XIII, XIV.]

Between fifty and sixty members of the Association and their
friends assembled at Keswick, making the Park Hotel their
headquarters. In addition to the official programme, unofficial
excursions were conducted on days preceding and succeeding
those announced in the official circular, under the leadership of
Mr. J. Postlethwaite, F.G S.

Monday^ August 20th. — The day was mainly devoted to an
examination of the characters of the Falcon Crag and Bleaberry
Proc Geol. Assoc, Vol. XVI, Part 10, November, 1900.]

PROC. OEOL. Assoc 1900.
\o o \Con/sfon Limestone & Silurian.

\ A \ShQp Rhyolite Croup.
I V \Shap Andesite Group.
\v:\Sca¥^€/fAshe3 & Breccias
\ 'Z^ I Ullswateril ^ycott Croup.
[ff| Falcon Crag Croup
\^z\Skidda\^ Slates,
\'¥'^\Granil'e, Gabbro &c,
\cfi\ Intrusive ? Garnet Rocks.
\i Dips

Provisional Map

OF THE

Volcanic Rocks

OF THE

Lake DISTRICT ^

By J.C MARR
ii ALFRED MARKER

Scala
t Inch ^^41^/1^3,

To lac$ foi;* W.'\

LONG EXCURSION TO KESWICK. $27

Fell group of volcanic rocks. Passing beneath the base of Castle
Head, formed of diabase, which Mr. Clifton Ward looked upon as
possibly occupying the neck of one of the old volcanoes, the
first halt was made in a cutting of purple breccia in the road
beneath Falcon Crag. The Director explained that this occurreii
between the Skiddaw Slates and volcanic rocks, and stated that
he and Mr. Harker were disposed to regard it as a crush-breccia,
though the evidence, which was not solely derived from the rocks
of that section, was not quite convincing. The terraced outline
of Falcon Crag and the adjoining Fell was noticed from this
point, and explained as due to the alternation of hard lavas and
softer ashes, which lay nearly horizontally, and which had not
undergone much alteration.

The party left the high road somewhat farther on, and walked
to Ashness Bridge, where the contrast between the smooth, peaked
hills of Skiddaw Slates and the rough, craggy eminences of the
volcanic rocks was pointed out, as also the nature of the delta
separating Derwentwater from Bassenthwaite, and of the islands
(which are little drumlins) of the former lake.

Lodore was next visited, and the compact lava with platy
jointing just beyond the fall inspected. The members of the
excursion were interested in the marks of glaciation about Grange
Bridge, especially by the excellent roche moutonn^e of Skiddaw
Slate on the left bank of the river.

The junction of Skiddaw Slate and volcanic rock on the
hillside above Hollow's Farm was next visited, and a member of
the party succeeded in obtaining a specimen of the two rocks
welded together. The general impression appeared to be that
the junction of the two series at this spot was truly conformable.

On returning to the high road, the crushed " rain-spot "
breccias of Quay Foot Quarry were inspected, as also the remark-
ably folded and cleaved vesicular lavas and ashes by the roadside
to the north of the Rosthwaite alluvial flat, and an accumulation
of drift on glaciated rock near the same place (see Plate XIV,
fig. 2).

On arriving at Rosthwaite the party drove back to Keswick.

Tuesday y August 21st. — Most of the members left Keswick by
the 9.40 train, arriving at Threlkeld about ten a.m. They were
there joined by Mr. Harkowitz, the proprietor of the Threlkeld
Quarry, who conducted them to the quarry and explained the
processes involved in the formation of concrete paving-stones
from the refuse of the micro-granite. The large quarry was then
visited, and the character of the micro-granite studied. The
remarkably even jointing of the rock, simulating stratification,
was duly noted, but the inclusions in the micro-granite afforded
the chief interest to the members. Inclusions of Skiddaw Slate
and of volcanic rocks (the latter containing garnets in places) were

528 lONG EXCURSION TO KESWICK.

collected, and also specimens of garnet in the micro-granite itselL
The latter, it was suggested, might have been derived from the
volcanic rocks. A large inclusion of Skiddaw Slate was seen in
one part of the quarry ; this did not appear to have undergone
much alteration.

On leaving the quarry, the process of forming setts by hand
was seen. The President proposed a hearty vote of thanks to
Mr. Harkowitz, the proprietor, for his courtesy in admitting them
to the quarry, and for conducting them over it, and also to his
foreman, Mr. Bragg, for assistance. This was carried by acclama-
tion, and Mr. Harkowitz briefly replied, and expressed his
pleasure at having been the means of affording the members a
chance of viewing the works.

The rest of the party reached Threlkeld shortly before noon,
and a move was then made up the Glenderaterra valley, where
the effects of metamorphism of the Skiddaw granite on the
Skiddaw Slates was studied. Members first passed over normal
Skiddaw Slate, and halted for lunch by a waterfall in the stream
north-east of the Blencathara Lead Mine, where they examined
the chiastolile slates ; a move was then made to Roughten Gill^
where the spotted andalusite slates were found, and then to
Sinen Gill, where the granite was studied, and the mica slates, in
the innermost zone of metamorphism, were found in contact
with the granite, at its summit. One member found a pegmatite
vein in the granite at this point.

The party separated here, some returning to Keswick over
the summit of Skiddaw, others by the slopes of Lonscale Fell,
while the rest walked to Threlkeld Station, in time to avoid a
thunderstorm accompanied by heavy rain.

Wednesday^^ August 22nd. — The members drove from the
Park Hotel at 9.30, and alighted at Seathwaite, which, as they
had occasion to learn by actual demonstration, is noted for its
rainfall. In walking up to Sty Head Tarn, they saw good
moraine mounds between the hamlet and Stockley Bridge, and
on the slopes above Stockley Bridge studied the garnet-bearing
rocks which are here fully developed, and formed by alternation
of breccias and lava-like rocks with a "streaky" flow-like structure.
The question as to whether these were contemporaneous or in-
trusive was discussed, and the prevailing opinion seemed to be
that they were in this locality truly contemporaneous. The
remarkable structures in the banded ashes above Sty Head Tarn
were examined, and the characters of Sty Head, Sprinkling, and
High House Tarns, and of several gullies, including Peers Gill on
Lingmell, were noted. Owing^to the rain, it was felt advisable to
return by Sty Head instead of proceeding down Grainsgill, and
excellent scenic effects were observed in spite of (or rather owing
to) the rain. Some of the members ascended Scawfell Pikes, and
experienced another thunderstorm.

LONG EXCURSION TO KESWICK. 529

Thursday y August 23rd. — As the morning opened with heavy
Tain, the Director met the party at the Keswick Museum, and gave
a demonstration, with the assistance of the late Mr. Clifton Ward's
maps, and of the well-known relief model of the district. Shortly
after eleven the weather cleared, and a number of the members
started in char-a-bancs for Honister Pass. Two well-marked
terminal moraines were seen in the valley above Seatoller and an
interesting case of diversion of drainage due to the operation of
the " law of unequal slopes " was observed at the top of the pass.
Here a number of rivulets course down the cirque-like termina-
tion of the valley, but the two northerly ones have been captured
by the streams draining into Buttermere, which has sawn through
the ridge, causing the deflection of drainage, and giving rise to the
marked cliff of Honister Crag.

The slates of Honister Crag were noticed, and the drive re-
sumed for Buttermere, where the Honister party was joined at
lunch at the Buttermere Hotel by another section, who had
driven direct to Buttermere through the Vale of Newlands.

After lunch boats were taken across Crummock to Scale Force.
The shingle spit connecting Low Ling Crag with the mainland
was pointed out, near the landing-place, and also the position of
the main lava here mapped by Clifton Ward as interstratified with
the Skiddaw Slates. At Scale Force, the party hammered the
granophyre, and saw that the position of the Force was originally
determined by the superposition of the laccolitic mass of granophyre
on the softer Skiddaw Slates. The now familiar thunderstorm
was experienced when returning in the boats. The members
eventually drove back to Keswick by the Vale of Newlands.

Friday^ August 24th. — At 9.30 the members of the excursion
drove to Rosthwaite, and thence walked up the Langstrath Valley,
as far as Blea Crag. On leaving Rosthwaite, the Director pointed
to a moraine which started from the ridge near Stonethwaite
Church, and eventually became plastered against the rocks of
Rosthwaite, giving rise to an alluvial fiat, and probable diversion
of drainage. Beyond Stonethwaite, the Ullswater lavas were
tapped near Galleny Force, and the garnetiferous rocks, resembling
those of the Sty Head path, to the south of this. The Director
drew attention to cases of diversion of drainage by glacial inter-
ference. The first case he characterised as doubtful, the second
and third as less so, and the fourth, which he had already described
in the Geographical Magazine^ as the most convincing. It was
noted that the stream, when passing over the hard garnetiferous
rocks in the second and third cases, had scarcely cut any channel,
but that in the fourth case a well-defined gorge was cut through
the softer and well-jointed banded ashes which there exist. The
Director called attention to the miniatures of small rock-basins in
these banded ashes, owing to the weathering influence of vegetation
on gently-sloping rock surfaces ; he also pointed out some

admirable potholes at the upper end of the gorge. One of the
members discovered a peg-like process at the bottom of the pothole,
in its centre, surrounded by a ring-like depression, proving very
satisfactorily the effect of the gjrration of pebbles in forming the
hole.

The intrusive garnet-bearing rocks of Blea Crag were next
examined, and Mr. £. £. Walker, B.A., who is occupied with
their study, explained what he had learned about them.

Most of the members returned to Stonethwaite by the west
side of the valley, as the bridge over Greenup had been carried
away by a flood in 1898, of which the members had seen the
traces, near Stonethwaite, earlier in the day.

The top of an extensive mass of garnet rock, seen in contact
with banded ashes, was visited on the east side of the valley,
nearly opposite Stonethwaite Church, and the members then
returned in carriages from Rosthwaite.

In the evening, after dinner, the President read a letter
which the Director had received from Mr. W. H. Hudleston, F.R.S.,
who was one of the Directors of the previous excursion of the
Association to Lakeland, nineteen years ago, and the members
now present requested the President to send a cordial message to
Mr. Hudleston, on their behalf. He then proposed a vote of
thanks to the Director, and also to Mr. Postlethwaite, who had
kindly conducted excursions.

These gentlemen briefly replied, and acknowledged the vote.

Mr. Teall, President of the Geological Society, proposed a vote
of thanks to Mr. Meeson, to whose care in making arrangements
the success of the excursion was so largely due. Mr. Meeson
replied.

Saturday, August 2^th. — The members started for the last
excursion in heavy rain, but fortunately, before the train had
reached Troutbeck Station, the weather cleared, and remained
fine during the day. From Troutbeck Station they drove to
Patierdale, and visited the Slate Quarries near the head of
Ullswater. The Director explained that the slate at that spot
was in the Scawfell Ash Group, and was brought down to that
low level from the upper slopes of Helvellyn, by a thrust fault
ranging through the Grizedale Valley.

Some of the physiographical features of the region were
pointed out, and the party ihen made its way to the landing-pier
and took steamer down the lake. On board the steamer, the
Director showed how the outcrop of the junction between the
Skiddaw Slates and volcanic rocks was only explicable on the
hypothesis of a fault having a fissure which was nearly horizontal.
The isolated patch of volcanic rock resting on the Skiddaw
Slates opposite Howtown was specially noticeable, and also the
inclination of the divisional planes of separation of the different

SUPPLEMENTARY EXCURSION TO CAUSEWAY FOOT. 53 1

members of the volcanic rocks, and their abutment against the
fault-plane.

At Pooley Bridge the Old Red Conglomerates were studied.
The Director gave a sketch of the history of previous opinions
concerning this rock, after which Mr. R. D. Oldham, Su-
perintendent of the Geological Survey of India, directed at-
tention to its resemblance to sub-aerial torrential accumulations
formed in regions of general dryness, such as are found in
Baloochistan and other parts of Central Asia. (See PI. XIV, fig. i.)

The party returned by coach to Penrith, and thence by train
to Keswick.

On the following day some members of the Association drove
round Thirlmere. At the King's Head, Thirlspot, a small con-
tingent left the others, and made the ascent of Helvellyn, and
at the Nag's Head, Wythbum, Mr. Marr led the President, ex-
President, and a few others over the fell to Watendlath, and
thence to Keswick. These studied the Armboth Dyke and some
rocks occurring in a crush-belt above Watendlath Tarn.

August 2jth„ — Mr. Marr accompanied some of the members
of the Association to Waterhead, Windermere, by coach. From
Waterhead a move was made to Skelgill, where the Coniston
Limestone and the various zones of the Skelgill graptolitic shales
were pointed out. Most of the party returned to Keswick, but
one or two walked to Windermere Station and made a cursory
inspection of the beds of the Upper Slates from the Coniston
Fla^s to the Bannisdale Slates.

Erratum. — A mistake was unfortunately made in drawing
Fig. 2 (p. 466). The Bed 2 on the west side of the fault should
be about \ mile farther south. The positions of the beds are
correctly stated in the text. J. E. M.

Long Excursion (continued).

SUPPLEMENTARY EXCURSION TO CAUSEWAY
FOOT.

On the igth of August^ 190O1 a party of twenty-one, under the
leadership of Mr. John Postlethwaite, F.G.S., walked to the
Vale of Naddle. On the way, charming views of Derwentwater
and the valley of the Derwent were obtained.

The leader of the party drew attention to a number of
boulders perched upon the eastern end of Skiddaw, more than
1,200 feet above sea-level, and pointed out the line of junction of
the Skiddaw Slates and the Volcanic Series. Near Causeway
Farm the junction was examined in detail. The soft, shaly con-
Proc. Geol. Assoc., Vol. XVI, Part 10, November, 1900.]

532 EXCURSION TO STROOD AND HALLING.

•dition of the uppermost bed of Skiddaw Slate was noted. The
lowest member of the Volcanic Series is here seen to be a lig^
grey, compact lava, about 1 50 feet in thickness, and is overlain by
a lava much darker in colour and more crystalline in stractuier '
The western mass of the St. John's quartz-felsite next received*
attention. Afterwards the members returned to Keswick.

SUPPLEMENTARY EXCURSION TO EYCOTT HILL.
AND THRELKELD MINE.

Monday, August 27TH, 1900. '

The members remaining in the Lake District visited Eycott Hill ■
and Threlkeld Mine under the leadership of Mr. John PosTUfr- .
THWAITE, F.G.S.

They proceeded by train to Troutbeck, and walked thence to
Eycott Hill, where two exposures of enstatitic lava were inspected, j
Leaving this interesting section, shortly after mid-day, they paid ft:
visit to the Threlkeld Mine, where, through the kindness of ■
Captain Bawden, they were able to examine the process of
dressing the ore (containing galena and blende), and to collect
specimens from the rough material as it is taken out of the mine.
There are two veins, one bearing 10** E. of N., the other bearing
25" W. of N., the veins running together in the northern part
of the mine. I'his mine has been worked northward into the
chiastoHte slate.

EXCURSION TO STROOD AND HALLING.

Saturday, September 8th, 1900.

Director: G. E. Dibley, F.G.S.

Excursion Secretary : H. A. HiNTON, B.Sc.

(Report by THE DIRECTOR.)

The members arrived by the 10.45 ^•"^- train, and walked to the
pits known as " The Quarry." (All the pits visited during the
excursion are described in the Proceedings, vol. xvi, pp. 484-
487, so that no detailed account of them is necessary here). A
large upper valve, with part of the lower valve, of Inoceramus
volutus was seen, and the Director obtained an undescribed
Fecien.

From this pit the members walked to Messrs. Martin & Earle's

pits, and thence to Messrs. Booth's pit, where fossils characteristic

of the zone of Holaster planus were obtained. Afterwards, by

the» kind permission of the Manager, Mr. Craske, the members

Proc. Geol. Assoc, Vol. XVI, Part 10, November, 1900.]

^Roc Geol. Assoo, I90CX.

Vol- X\n. PiATX XIY.

Fig. I. — Old Red Conglomerate, Poolev Bridge. Ullswatex.

Fig. 2. — Drift on Glaciated Rock North of Rosthwaite,
i^Front photographs by A, K. CoomarO'Srvaimy^ F.G Sj,
Tofacgpag§332.]

EXCURSION TO ORPINGTON. 533

were conducted over the cement factory by the foreman, Mr.
Usborne, who described the process of the cement manufacture,
A vote of thanks was accorded the Manager and Mr. Usborne for
their kindness.

Messrs. Hilton & Anderson's pits at Hailing, in the zones of
Rhynchonella cuvieri, Actinocamax plenus^ and Holaster subglobosus
were next examined.

The next pits visited were those of Messrs. Lee & Co., at
Holborough, the finest exposures of chalk on the west side of the
Medway. The Actinocamax pknus-X£i2x\% here form a very con-
spicuous feature in the upper part of the lower pits. A large
number of typical fossils were at the disposal of the members.

After tea at the Bull Hotel, Snodland, a cordial vote of
thanks to the Director was proposed by Mr. Sherborn, and
carried unanimously.

REFERENXES.

Geological Survey Map, Sheet 6.

Ordnance Survey Map, New Series, Sheet 272. is.

1872. Whitaker, vV. — "Geology of London Basin.'* Mem, Geol. Survey^

vol. iv.
1887. Woodward, H. B. — " Geologj' of England and Wales.*

EXCURSION TO ORPINGTON,

Saturday, September 2 2nd, 1900
Director: T. V. Holmes, F.G.S.

Excursion Secretary: A. C. YOUNC, F.C.S.
(^Report by THE DIRECTOR.)

The object of this excursion was to see the Tertiary sections now
exposed, between Chiselhurst and Orpington, on the S.E.R. main
line, which is being widened.

The party, numbering more than forty, assembled at Orpington
Station and proceeded northward towards Chiselhurst. A few
yards south of the station bare Chalk is visible, but at the
northern end of it a fine clear section of Thanet Sand, capped by
a few feet of greenish-looking Woolwich Beds, appeared. Unfor-
tunately it was impossible to examine the Woolwich Beds otherwise
than by means of such fragments as had fallen down. Before
leaving the precincts of the station, the Director called attention
to the slight anticlinal and synclinal folds between Orpington and
the cutting south of Grove Park. Between Orpington and
Chiselhurst there is a slight synclinal fold. Then at Chiselhurst
a slight anticline causes the appearance of the Chalk and Thanet
Sand there. At the southern end of the Sundridge tunnel the
dip is northerly, and, at the northern end, southerly, the tunnel
Proc. Geol. Assoc, Vol. XVI, Part 10. November, 1900.] 40

534 EXCURSION TO ORPINGTON.

being consequently through a synclinal fold. On July 22nd it
viras evident that a slight anticlinal fold existed between the mouth
of the tunnel, where the dip was southerly, and the beds northward
of the bridge crossing the line a tew yards away, which had a
steady north-westerly dip towards Grove Park Station.

Proceeding northward, the party noticed Thanet Sand on the
more westerly side of the line, where it is being widened, to a point
a little beyond the spot at which the footpath crosses the railway.
Thence, little worth noting could be seen until the north-western
comer of Clay Wood was reached, and there a small siding showed
the shell beds of the Woolwich Series to a thickness of 6 feet
The shells were mainly Cyrenas. Between this point and Town
Court Farm there was a sectionless interval. But in the cutting
which begins a few yards south of Towncourt Wood, London Clay
appeared, containing many of the calcareous concretions known
as "race." London Clay was also seen in the cutting on the
north-western border of Towncourt Wood. There being no
sections thence to Chiselhurst, the party separated at the northern
end of the cutting.

The President kindly assisted in the elucidation of doubt-
ful points, and distributed proofs of p. 135, vol. i, of his
Memoir on "The Geology of London and of part of the
Thames Valley," (1889), in which the results of visits to the
Orpington Cutting many years ago are given. As the Memoir in
question, though valuable, is by no means portable, and as the
sections between Orpington and Chiselhurst may retain their
clearness, and possibly develop rather than deteriorate during the
next few months, it may be useful to give here all that refers to
the scene of our Excursion :

" The cutting on the South Eastern (I^wisham and Tunbridge)
Railway at Orpington Station must have given a fine section when
clear. When I saw it first the greater part was unfinished, and
when again, in 1870, the sides were overgrown; however the
following succession could be made out :

Sand of the Oldhaven Beds, at the highest part.

I Clay.
Woolwich Beds ) Shelly clay, with peaty earth at bottom.
Clay.
• Pebbly green sand.
Thanet Sand, cut into from the end near the Station up to as far as the
footpath across the line.

" The lines of growth on the sides of the cutting show distinct
and even bedding, dipping at a small angle along the line N.W.

" Mr. E. Nash has published the following details of the beds
shown in part of this cutting,* and he tells me that his notes were
taken at about 300 or 400 feet from the Orpington end, that is to

•** Pre-Adainite London," pp. 30, 31, 8vo, London, 1879.

PROCEEDINGS.

535

say, south-west of the highest part, and beyond the on-coming of
the Oldhaven Beds.

of broken I

\^cgctablc clay earth

Yellow clay

Yellowish earth, with traces
shells

Yellow earth, gradually getting blue

and of a deeper colour downward ;

Woolwich charged with fragments of shells, in-

3^s, -{ creasing in quantity with the depth ...^

Layers of perfect shells, compacted into
a hard bed

Very black soft earth, with some frag-
ments of shells

Dark pebbles and sand

Hard green sand, with dark stripe at

bottom

Light-coloured clean [? Thanet] sand, not bottomed."

Feet.

[? about II.]

about 3

[ ? about 4]

[ ? over 4]

ORDINARY MEETING.

Friday, June ist, 1900.

W. Whitaker, B.A., F.R.S., President, in the Chair.

Sir Henry H. Howorth, K.C.I.E., M.P., etc., Geoffrey A.
Longden, and John B. Miles, B.Sc, were elected members of the
Association.

An interesting address on "Our Older Sea-margins" was
delivered by Sir Archibald Geikie, D.C.L., F.R.S., etc The coast
terraces of North-Westem Europe, and more especially those of the
east and west coasts of Scotland were described and illustrated
by means of the lantern. After discussing the various theories of
their origin he pointed out the importance of obtaining more
accurate measurements of the heights of the terraces with the view
of determining any inequalities in their levels, and he suggested
this research as one in which valuable services might be rendered
to geology by any competent observer who had time and
enthusiasm to devote to it.

ORDINARY MEETING.

Frid.w, July 6th, 1900.

W. Whitaker, B.A., F.R.S., President, in the Chair.

F. P. Mennell was elected a member of the Association.
The following paper was read :

" Notes on the Geology of the English Lake District," by J.
E. Marr, M.A., F.R.S., F.G.S., illustrated by lantern slides.
Proc. Geol. Assoc., Vol. X\'I. Part 10, November, 19C0.]

537

INDEX TO VOL. XVI.

PACE

Abbott, Dr. ... 60, 286

Acantkias ... 2

Actimocamax pUnus-zont^ 157,

250, 487-496, 500, 533
„ quadratus - zone.

289-368, 339, 500
Aiiobatis ... 5

Aldrington, Excursion to ... 248

Allegheny Plateau ... 86

Allen, H. A. loi, 163, 255

Angers Slates ... 233, 235

Annual Meeting (1899), 94; (1900) 388

Anstey's Cove

438

Apatite

... 369, 370

Aplite

S03

Archaean of Brittany

104

„ of Malvern

•.. 503. 505

Arlcscy

446

Armorican Sandstone

108, 233, 234

Ashness Bridge

527

Axmouth

135

Aylesbury, Portland and Pur-

beck at ...34,42,43

Babbacombe ... 433,434

Bagshot Scries 140, 151, 153,

433.434,514,519-521
Bargate Stone ... 254,255

Barkingside ... 272

Barnes, J. ... 221,223

Barrois, Dr., 394 ; on Brit-
tany ... loi, 231
Barton Beds ... 519
Bather, F. A., 60, 286, 387 ;

on Wind- worn Pebbles ... 396

Bay ford ... 447

Beaudesert Park ... 246

Beer stone ... 139

Beheaded streams ... 85

Bemrose, H. A., on Carbon-
iferous of Derbyshire, 165-
221 ; Excursion to Derby-
shire ... 221-225
Bennet's End, Brick-earth at,

501 ; Chalk at ... 502

Betch worth, 155 ; Zones of

Chalk at ... 156

Bezier, M. ... 232, 240

Bier ton, Hartwell Clay at, 35 ;

Portland at ... 31,34

Bindon Cliffs ... 134

Birley, Miss ... 287

Proc. Geol. A.«soc., Vol. XVI.]

Bishopstone, Portbnd and
Purbeck at, 42 ; beds

Blackdown (Devonshire)

„ „ Fossils of

Blake, J. H., Excursion to Sil
Chester

Blake, Prof., 59, 133, 287, 516
Excursion to Bushey

Bleaberry Fell Andesites

Blencathara Mine

Blue Bell Hill Chalk Pit ..

Bois-Roux

Bonney, Prof.

Borehole at Grove Park

Borrodale, Volcanic rocks of..

Borstal Manor

Bovey, 425 ; Lignite of

Bowder Stone

Bowdon Pebble, The

Bowerman's Nose

Boxmoor, Excursion to

Bracklesham Beds

Breccb, Rain-spot

Brehec

Brickenden Gicen

Brighton

Brill, Portland at, 36 ; Purbeck
at

Brioverian 105, 232,

British Museum (Natural His-
tory)

Brittany, Archaean of, 104
Dr. Barrois on, loi, 231
Brioverian of, 105 ; Cam-
brian of, 107 ; Carboniferous
of, 114 ; Devonian of, 113 ;
Eruptive rocks of, 116;
Excursion to, 231-243 ; Gen-
eral Structure of, 131 ;
Granites of, 116; Intrusive
rocks of, 116; Ordovician
of, 108 ; Sedimentary rocks
of, 103; Silurian of, 112;
Succession of Palreozoic and
Archaean

Brown, G. F.

Budleigh Salterton

Bugle Pit, Hartwell

Bullen, Rev. A., Excursion to
Reigate

Bunter Pebble-beds, Age of ...

Burham

48
143
144

513-5^6

243-244
453
528

250, 487
241
59, 286
523
453
488
426

479
396 // seqq,

431,442
501-502
519-521
527
238
447
248

235, 23<i

257, 445

104

133. 145

162

146
249. 487

538

INDEX.

Burrows, H. W.
Biishey, Excursion to

PAGE

59. 287
243-244

Cambrian of Hrittany ... 107

„ of Malvern ... 508

Cambridge Greensand ... 446

Cannock ... 246-248
Carboniferous, of Derbyshire,
165-225 ; of Brittany, 114 ;

Literature of ... 220

Carcharias ... II

Carchariidac ... 12

Carcharodon ... II

Carnac ... 236

Carr, Prof. ... 221,225

Caterham, Excursion to ... 510

Causeway Foot „ ... 531

Caverns ... 178

Cayeux, M. ... 128

Cenosphtgra in Brittany ... 128

Cistracum ... 40

Chadwick, W. H. ... 286
Chalk, of Beer, 138; of
Betch worth, 156 ; of Croy-
don, 484 ; G. E. Dibley on,
484 ; Divisions of, 293 ; Fos-
sils of, 359, 492 ; of Graves-
end, 484 ; of Rochester,
484; Dr. A. W. Rowe on,
289; Zones of, 289-367,

484-496, 500

Chalk Marl ... 488, 492

Chantries ... $12
Chapman, F., Excursion to
Aldrington, 248; onPurbeck
Foraminifera andOstracoda,
42, 43,58; on Raised-Beach

and Rubble-Drift ... 259-270

Charlton, 489 ; Excursion to 257

Chatellier,234; Sandstone 109

Chatsworth Grit ... 191

Cher well ... 88

Chessington ... 256

Chiltern Hills, Excursion to 251-254

Chiselhurst ... 522,533

Chudleigh ... 425

Clayden, A. W. ... 148

Claygate, Excursion to ... 256

Cliffe ... 488

Coal Hill ... 509

Coastal Plains ... 75

Coke, G. E. 22 [, 222, 225

Collins, F. G. ... 148,151

Coin ... 91

Colwall ... 508,509

Colyer, Mr. ... 513
Coney Hill, Portland and

Purbeck at 35, 42, 43

Coniston Flags ... 466

„ Limestone ... 466

PACE

Consequent streams ... 80

Conversazione, November,

C1898), 59 ; (1899) ... 286

Coomara-Swamy, A. K., 286 ;

Excursion to Guildford ... 254,512
Coombe Warren ... 443

Corby ... 226-230

Cordierite, and its Associates,
J. J. H. Tcall on the Natural

Historyof,6i ; bearing

rocks of Scotland, 63 ;

gneisses, 62 ; Literature of 74

Cornbrash ... 517

Corner, Dr. 272, 273, 275, 282

Corundum, 61 et seqq. ; pro-
duction of ... 70
Cotmore Walls ... 32
Cotteswold Hills cuesu ... 87
Council (1899), 100; (1900) 395
Cranford St. John, Oolites at 517
Crayford * ... 257
Crich 169 // seqq,
Crosfield, Miss, Excursion to

Reigate ... 162

Cuddesdon, Portland and
Shotover Beds at, 28 ; Pur-
beck at ... 41
Cuestas, W. M. Davis on the

drainage of ... 75

Culm Measures ... 428,440

Cuxton, 486 ; Excursion to,
249 ; Rhynchocephalian
bone from ... 496

Dartmoor ... 430

Davies, A. M., on the Thame
Valley, 15; Excursion to
Thame ... 157

Davis, Prof. W. M., 394 ; On

the Drainage of Cuestas ... 75

Dene ... 226-229

Derbyshire : H. A. Bemrose on
the Lower Carboniferous of,
165, 221 ; Ashover inlier,
175 ; Calcareous tufa and
warm springs, 194 ; Caverns
and underground water, 178;
Crich inher, 175 ; Dolo-
mitized limestone, 219 ;
Excurs. to 221-225 ; Glacial
Drift, 193 ; Igneous rocks,
195, 210, 215 ; Kniveton
inlier, 178 ; Lavas, 202 ;
Lead and lead-mining, 182 ;
Literature of, 220 ; Local
rock formations, 169; Main
inlier, 169 ; Marmorized
limest., 219 ; Metamorphic
limest., 184 ; Millstone
Grit, 189 ; Mountain

INDEX.

539

Limcsi., 169, 217; Petro-
graphy, 213 ; Sands and
Fireclays, 192 ; Silicified
limest., 219; Sills, 206;
Volcanic vents, 197 ;
Yoredale rocks

Devonian of Brittany
„ of Devon

Dibley, G. E , 59, 287, 288,
395 ; On the chalk-pits of
Rochester, Gravesend and
Crovdon, 484 ; Excursion
to Cuxton, 249 ; Excursion
to Purley, 518 ; Excursion
to Strood

DictyoKtma - shales

Dinton, Portland at
„ Purbeckat

Director-General, Geological
Survey 59, 98,

Doabs

Dreikanter, 398 ei segg. ;
Doppel

Dunchideock

Dun con Green

Eastbourne, Excursion to
Edmonds, H., Excursion to

Aldrington
Eilach 8

Elephant Bed
Elliott, R.

Emary, Percy 59, 100.

Eocene of Devon 140,

Eocene Sharks and Skates, I ;

List of English
Erith

Etna, F.W. Rudler on
Evenlode
Excursions (1898) 97 ; (1899)

392 ; Committee

(1899)98; (1900)
Exeter, 149 ; X'olcanic rocks

near
Exmouth
Eycott Hill

186,210
113, 240
425.442

532

S09

286, 393
75

400, 405
149
489

500

248
I et segg.

249

286, 395

151.426

257

288

88,89

393-394

148 149

145

532,455

Facetted stones. 399 et segg. ;
Action of blown sand on,
402 et segg. ; Recorded
localities and geological oc-
currence of, 4I I ; Literature
of

Falcon Crag Andesites

Farningham Road

Fletcher, L.

Flower, Sir W. H., Death of

Foley, Miss

Foord, A. S.

416

453
489

445
388
287
287

Foraminifera, in Carboniferous
Limestone, 174 ; from Ele-
phant Bed, Brighton, 270 ;
Purbeck, 42 ; of Raised-
Beach near Portslade, 264,
267 ; of Rubble-Drift near
Portslade ... 269

Fossils : Armorican Sandst.
109, 147 ; Bagshot, 521 ;
Blackdown, 144 ; Carbonif-
erous, 116, 172, 223, 224,
241 ; Chalk, 138, 139, 289-
367, 484-499; Devonian,
113, 441 ; English Eocene
(Fish), 13 ; Hartwell Clay,
26-38 ; llford, 277, 282 ;
Keuper, 1 36 ; Lower Green-
sand, 255 ; Ordovician,
109 ; Portland, 20-58 ;
Purbeck, 39-44, 5^ ; Raised-
Beach, 261-270; Rhaetic,
136. 442; Silurian, 112;
Thame Valley, 20-58 ;
Wenlock ... 508

„ Lisu of, 13,43,263-270,

277,283,359.492, 521
Francis, J. ... 60

Frasnian ... 429,440

Frith Hill ... 255

Galeocerdo ... 12

Galeus ... 12
Garnets 455, 528-530
Garsington, Portland at, 19,

26, 27 ; Purbeck at ... 39

Gault, Thame Valley ... 55
Geikie, Sir A., 257, 393 ; on

Our Older Sea-margins ... 535
Geology of the Thame Valley,

A. M. Davies on ... 15

Glenderaterra ... 528

Godalming ... 254

Godstone Quarry ... 511

Granites of Brittany ... 116

„ of Lake District ... 472

Granoph3rre ... 474

Gravesend ... 489
Great Hazeley, Portland at,

30; Bishopstone Beds at... 51
Great Milton, Portland at,

29 ; Bishopstone Beds at... 52
Great Oolite ... 517
Green, Upfield, 60 ; Excur-
sion to Boxmoor ... 501
Gregory, Dr. J. W., on

ZeuglopUurus ... 353
Gretton ... 226, 229

Greywacke of Faou ... 241
Groom, Prof. T. T., Excursion

to Malvern ... 503-5 10

540

INDEX.

Grove Park, Excursion to,

522 ; Boring at ... 523

Guildford, Excursion to ... 254, 512

Gwinnell, W. F. ... 59, 287

Haddenham, Gault at

„ Portland at ...

Haldon

149

Haling Pit

490,518

Hailing

532

Hardy, J. D.
Harcfield

244

245

Harker, Alfred 449 tt seqq.^

527

Harkowitz, Mr.

527

Harrison, B.

Harrow Weald

243

Hartwell. Portland and

Purbeck at, 24 ; Clay

34.35

Herries, R. S. 231,

242,

256

Hertingfordbury, Excursion to
Hicks. Dr. H., Death of ...

288

447
388

High Terrace Drift

271

Hill, W., Excursion to Hitchin

446

-447

Hind, Dr. Wheelton, 221-

223 ; on Yoredale rocks ...

187

Hinton, M. A. C, on Pleisto-

cene of 1 1 ford and Wan stead

271

-281

Hinton, M. A. C.

Hitchin, Excursion to, 446 ;

Freshwater deposit near ...

447

Holaster p/anuS'Zont, 138, 250,

310, 325

486-496

„ sufig/ofiosus-zonCy 157,

487-496

500

Holborough

487

533

Holland, R.

,288

Holmes, T. V., Excursion to

Grove Park, 522 ; Excursion

to Ilford, 160; Excursion to

Orpington

533

Hook

519

Hopkinson, J.

.244

Howler's Heath

509

Howorth, Sir H. H.

535

Hudleston, W. H., 133, 454,

530 ; Museum of

133

Hunt, A. R. 425,

430, 433

Hut circles

431

Hypirodapedon from Devon-

shire

142

Hypotodus

Ide ... 149

Ilford, 271-286 ; Excursion to.

160 ; Non-marine Mollusca

of, 282, 283, 285; Verte-

brata of ... 277

Income and Expenditure

(1898). 94 ; C1899) ... 389

Isle of Man, G. W. Lamplugh
on

Johnson, J. P.
Jukes-Brown, A. J.

Kenley

Kennard, A. S., 60 ; on Pleis-
tocene Mollusca

Kent Coast, Zones of the
Chalk of

Kentmere - Coniston Slate
Band

Kent's Cavern

Kesion

Keswick, Excursion to
„ Museum

Kettering, Excursion to

Keuper

Kinder Scout, 222 ;

163

285
lOI

Grit
King's Cross, Haddenham...
„ „ Purbeck at ...

Kingston
Kirby

Kitchin, Dr. F. L., on
Terelratulina rowei

490t 518
282

294

457
433
489

526-531
529
516

135
191

158

40t43

443

229

355

LabyrinthndoH from Sidmouth I42

Lag Faults ... 461, 463

Lake District. J. E. Marr
on the Geology of,
449-483, 526-531; Bowder
Stone, 479 ; Buttermere,
474 ; Carrock Fell intrusive
rocks, 473 ; Changes at
close of Lower Palaeozoic
Times, 460 ; Chiastolite
Slates, 528 ; Ennerdale,
474 ; Eskdale granite, 475 ;
Excursion to, 526 ; Faults,
462 ; Garnets, 455, 528-
531 : Garnet- bearing rucks
of Scawfell, 476 ; Geologi-
cal Survey of, 461 ; Glacial
and Post-Glacial deposits,
478 ; Granite of Eskdale,
474, and Skiddaw, 472 ;
Granophyre of Buttermere
and Ennerdale, 474 ; Green
Slates and Porphyries, 453 ;
Intrusive igneous rocks,
472 ; Lag faults, 461, 463 ;
Later rocks of, 471 ; Litera-
ture of, 482 ; Lower Palaeo-
zoic rocks of, 451 ; Micro-
franite of, 474» 5^7 ;
loraines, 203, 479 ; Phy-
siography of, 480 ; St.
John, Vale of, 474 ; Skid-
daw granite, 472 ; Skiddaw

iKDEX.

541

slates, 451, 527-532 ; Mcta-
morphism in the, 472 ; Tear
faults, 465 ; Upper Slates
of, 459 ; Volcanic rocks.
453, 466. 527. 531 ; Vol-
canic rocks of Borrodale ...

Lamnidse, 7 ; Lamna

Lamplugh, G. W.

Lane End

Lapworth, Prof., Excursion 10
LichBeld

Lasham, F.

Laval, Excursion to

Lead-mining

Lebcsconte, M. 232,

Lectures (1898), 96 ; (1899)

Ledbury

Lee, J. E.

Lezaie, La

Lichfield, Excursion to

Literature of, Cordicrite, 74 ;
Derbyshire, 220 ; Lake
District, 482 ; Phosphaiic
Deposits, 386 ; Rhyncho-
cephalia, 499 ; South Devon,
152, 441 ; Thame District,
159; Wind-worn pebbles,

Littleton

Locmariaquer

Lodore

London Clay

„ „ Basement Bed...

LongCrendon, 158 ; Portland
at, 20, 35 ; Purbeck, Shot-
over Sands, and Gault at ...

Louis, D. A.

Low-Terrace Drift

Lower London Tertiaries

** Lower Greensand '* of
Thame Valley, 44, 159;
Correlation of

Ludlow rocks

Lustleigh

MacEnery, Rev.

Malvern, Excursion to

Marmorized Limestone

Marr, J. E., Excursion to Kes-
wick, 526 ; on Geology of
the Lake District

Marsupites

Martin, P. A. B.

May Hill Sandstone

Meeson, F. 225,

Melboum Rock

Micraster zones, 301, 306. 327
329, 335, 359t 486-496, 492,

Microzoa of Raised- Beach and
Rubble-Drift

Millstone Grit

453
10

163

252

246 248

242

182

240, 242
392
508

429

241

246-248

416

254, 255

236

527

523,534

50',523

22, 39
60

273
501

53
508
430

436

503-510

219

449-483

294. 346

288

503, 509

240, 530

447

500, 518
259

Miln Museum

Moackton, H. W., 287, 514;
Lecture on the Glaciers and
Fjords of the Bergen Dis-
trict, 100 ; Lecture on Some
Features of the Recent
Geology of Western Norway

Monckton, H. W., Excursion
to Wimbledon, 443-445 ;
Excursion to Winchfield ...

Mont Dol 118,

Mont Su Michel

Moraines

Morosewicz, Dr., Production of
Corundum and Spinelle...

Mortimer

Mountain Limestone

Mourlon, M.

Museums, British, 257 ; Geo-
logical Society, 423 ; Mr.
Hudleston's, 133; Jermyn
Street, 257 ; Keswick, 529;
Miln, 236 ; Natural History,
257, 445 ; Reading, 513;
Torquay

Museums Visited (1898), 96 ;

Muswell Hill, Portland at ...
Myliobatis

YKCM.
236

420

153, 519
231, 232
231, 232
528, 529

513, 515
169

257

438

393

287

NeomylodoH lUtai

Netley Heath, Excursion to,

524 ; Lenham Beds at ... 524
Newland's Comer ... 524, 526
Newton Abbot, Excursion to 425,439
Newton, E. T., 59, 224, 520 ;

On a bone from the Chalk

of Cuxton ... 496

North, W. H. ... 287

Northfleet ... 489
Norway, H. W. Monckton on

Glaciers and Fjords of, 100 ;

on Recent Geology of ... 420

Notidanus serratissimus ... 6

Nottingham, Excursion to ... 225

Odontaspis .. 7

Ochlen, M. and Mme. ... 242
Oflficers and Council (1899)

100 ; (1900) ... 395

Ogwell ... 439

Oldham, R. D., ... 531

Oldhaven Beds ... 523

Old Red Conglomerate ... 531
Ordovician (Brittany),

189 I

Orpington, Excursion to,
Ostracoda, Purbeck, 42,

58 ; Raised Beach, 263, 267 ;

Rubble-Drift

108,

234, 235. 238
.-. 533-535
43,

268

542

INDEX*

PAGE

Otford ... 489

Otadus ... 10
Oving, Portland and Shotover

beds at, 36 ; Purbcck, 44 ;

Shotover Ironsandsat ... 48

Oxshott ... 256

Oxted ... 492

Oxyrhina ... ii

Papers read ( 1 898), 96 ; ( 1 899) 39 1

Parkinson, J. ... 287

Pattcrdale ... 530

Peasemarsh ... ' 254

"Pcndle" ... 42

Peran, Vitrified Camp at ... 237

Petrography, Derbyshire ... 213

Phosphatic Deposits, Natural
History of, 369-387 ; in
Cambrian of Nuneaton,
375 ; Cainozoic, 383 ; of
Clipperton Atoll, 373 ;
Cretaceous, 382 ; Devonian
of Tennessee, 378 ; Forma-
tion of 383 ; of igneous rocks
and mineral veins, 369 ;
Literature of, 386 ; Meso-
zoic, 379 ; Modern, 372 ; of
ihe Ocean, 373 ; Paioeozoic,
375 ; of Peru, 372 ; of
Potton. 382 ; of South
Carolina, 384 ; of Sweden 376

Photographs, Geological ... 99

Phyllades de St. L6 ... 105

Pine Mountain, Kentucky ... 87

Piper, J. R. ... 288

** Pipes " in Chalk ... 245

Placoparia ... 452

Plagioclinal structure ... 505

Pledge, J. H. ... 60

Pleistocene, of Devon, 427 ;
Deposits of Ilford and
Wanstead, M. A. C. Hinton
on, 271-281 ; Non-marine
Mollusca, A. S. Kennard
and B. B. Woodward on 282-286
Polign^ ... 234

Pooley Bridge ... 531

Portland of the Thame Valley,
18 ; Comparison of sections
of the ... 24

Postlethwaite J ,530; Excur-
sion to Causeway Foot, 531 ;
Excursion to Eycott Hill
and Threlkeld Mine ... 532

Potholes ... 530

Potter, G., ... 59

Purley, 490 ; Excursion to ... 51 S

Preston, H. ... 287

Pristis ... 3

Purbcck of the Thame Valley,

38 ; Ostracoda of the ...42, 43, 58

Quainton Hill, Portland at,
36, 44; Purbeck at, 44;

Shotover Ironsands at ... 48

Quarry Street, Guildford ... 512

Quintm massif ... 237

•* Race." 534 ; Analysis of ... 512

Radiolaria ... 428,429
Raised-Beach and Rubble-
Drift at Aldrington, F.

Chapman on ... 259-270

Raisin, Miss ... 59, 287

Read, C. H. ... 257

Reading Museum ... 513

Redland (Bristol) section ... 421

Reigate, Excursion to ... 162
Reid, Clement, 524 ; On the

Shapley Section ... 520
Rhactic, 135 ; Section at

Bristol, W. H. Wickcs on 421

Rhinoptera ... 5
Rhynchocephalia, Literature

of ... 499

Rhynchocephalian ? bone ... 497

Rhvnchonella cuboides ... 429,440
,, cuvieri-zon^y 138,

I57i 250, 317, 323, 486-496, 500, 533

Richmond Park ... 445

Rickmansworth, Excursion to 244-246

Rochester .. .^84

Roding River ... 376

Roflas ... 481
Rowe, Dr. A. W., 288 ; On

Zones of White Chalk ..* 289

Rosihwaite ... 527

Roitingdean ... 248

Rough Rock ... 192

Rouzic, M. le ... 236

Rubble-Drift at .\ldrington ... 259, 267
Rudler, F. W., on the last

great eruption of Etna ... 288

St. Aubin d'Aubign^ .. 233, 240
St. Germain-sur-Ille ... 340
St. Jean la Poterie ... 235
Salter, A. E.. 60, 286 ; Excur-
sion to Hertingfordbury ... 447-448
Sam's Green Pit (Ilford) ... 273,284
Sapphires, Montana ... 69
Scawfell Ash Group, 530 ;

Banded Ashes and Breccias 457

Schists d'Angers ... 109

Schmiecha
Sclater, Dr.,
Winchfield
Scoliodon
Scythe-Stones

Excursion to

80 et seqq.

519
II

143

INDEX.

543

Sea-beach in Carboniferous

Limestone ... 174

Seaford ... 500

Sea-margins, Sir A. Geikie on 535

Sea ton, Excursion to ... 133

Selachii, List of English

Eocene ... 13

Shale Grit ... 189

Shap, 457 ; Andesites, 453,
458 ; Conglomerate, 471 ;
Granite, 478 ; Rhyolite ... 453, 458
Shapley Heath, 519; Fish

remains at ... 521

Sharks and Skates from the

Eocene, A. S. Woodward on I

Sheer, J. ... 287

Sherbom, C. D., 288, 289, 368 ;
Excursion to Aldrington,
248 ; Excursion to East-
bourne, 500; Visit to Mu-
seum of the Geological
Society ... 423

Shotover Jronsands ... 46

„ Portland at ... 26

Sidmouth ... 140

Silchester, Excursion to, 513 ;

Roman City at ... 514

Sillimanite ... 62

Sion slates ... 109, 234

Silurian ... 112

Skiddaw slates, 451, 527-532 ;
Volcanic rocks in, 451 ;
Metamorphism of ... 473

Slade, J. ... 59

Soci^te Beige de Geologie ... 257

South Devon, Literature of ... 152,441
Southern Drift ... 514

Spcnccrwood ... 515

Spinelle, 61 ; production of... 70

Squatina ... 2

Staines, Excursion to ... 163

Stebbing, W. P. D., 59, 286,
443 ; Excursion to Claygate,
256 ; Excursion to Netley
Heath, 524 ; Excursion to
Winchfield ... 155

Stephenson, Mr. Mill ... 514

Stock ley Bridge ... 528

Stone, Portland at, 24 ; Pur-
beck, 42 ; Bishopstone Beds 49
Stromatactis ... 433
btrood, 484 ; Excursion to ... 532
Sty Head Tarn ... 528
Sugar Loaf Hill ... 505
Sussex Coast, Zones of the

Chalk of ... 321

Swabian Alb ... 79

Swanscombe ... 489

Teall, J. J. H., 59, loi, 286,
530 ; On Cordierite and its
Associates, 61 ; On Phos-
phatic Deposits

Tear faults

Terehratulina rowei

„ gracilis - zone,

138,250,315.324,492,

Terra Cotta Works, Wat-
combe

Tervet, J. H.

Thame Valley, A M. Davies
on, 15 ; Physiography of,
56; Excursion to, 157 ;
Portland Beds of

Thanet Sand

Thompson, Beeby,
Excursion to Weldon

Thrapston

Threlkeld

Tilburstow

Toadstone,
lavas, 202 ,

Toot Baldon Beds

Torquay Museum

Tot tern hoe Stone

Towersey, Portland and Pur-
beck at

Traveuzot

369
465
355

500, 518

432
59

516;

527:

195

without
• sills ...

31
534

226-231
516

528, 532
510

206

438

446

— 32, 39
234

Uintacrinus ... j^g

UUswater, 530 ; basic group 455

Upper Chalk at Harefield . . 245

Ussher, W.A.E. 133,425,433

Via Gellia ... 224

Vitrified Camp .'.'; 73,237

Volcanic rocks 148, 453, 466, 527, 531

1. vents ... ig7

Walton-on-the-Hill, Excursion

to
Walker, E. E.
Wanstead, High-Terrace Drift

of
Ward, Clifton 451 et siao.,
Warren, S, H. ...

Warren Farm Quarry
Watcombe, 432, 434 ; Terra

Cotta Works
Watts, Prof., Excursion to

Lichfield
Weldon, Excursion to
Wenlock Limestone

„ Shale
Wcsterham
Westleton Shingle
West Wycombe
Whitaker, W., 287,

503,

. --., 512,
518, 522, 534; Elected

155-157
530

271

527, 529

512

432

246
226-231

503,509
508, 509

489
252,448

251

544

INDEX.

President, 385 ; Excursion
to Godstone, 510; Excursion
to Staines, 163 ; Excursion
to Rickmansworth, 244 ;
Excursion to Wimbledon,
443 ; Excursion to Winch-
field ... 155
Whidborne, G. F. ... 438
White, Osborne, 87 ; Excur-
sion to Chiltern Hills ... 251
Whiteleaved Oak ... 508
Whornes Pkce ... 486
Whyieleaf ... 490,518
Wickes, W. H., 288 ; On a
new Rhaetic section at
Bristol ... 421
Williams, F. R. B. ... 59, 287
Wimbledon, Excursion to ... 443-445
Winchfield, Excursion to ... 153155
Winchfield and Hook, Excur-
sion to ... 519-522
Windrush ... 90
Windmill Sand-pit, Stone ...
Wind-worn Pebbles, F. A.
Bather on, 396-420 ; Sug-
gested Glacial Origin of ...
Wokingham

Wolborough ... 439, 441

Woodward. B. B., on Pleisto-
cene Mollusca
Woodward, A. S , 223, 257,
287 ; on Eocene Sharks and
Skates ... i

Woodward, Dr. H. ... 257, 429

Woodward, H. B., 59, 425,
432, 439 ; Excursion to
Newton. 425-442 ; Excur-
sion to Seaion ... 133-152
Woolwich and Reading Con-
glomerate ... 518
Would ham ... 250, 4S8

Xiphodolamia ens is ... 6

Yewdale Breccia ... 453

Yoredale Series, 186; Igneous

rocks of ... 210

Young, A^ C.

PACK

353

398

153

282

Zeugl 'pleurus rowei

Zonal Features of the Chalk, of
Rochester, 484 ; Burham,
487 ; Gravesend, 489 ; Croy-
don, 490; G. £. Dibley on 484-496

Zone of. Am. Jurtnsis^ S^^ »
Ac/inocamaxpUnus, 157, 250,
492 ; Actinocamax quadra^
'»*. 339 ; Holoiter pianuSy
138, 250, 310, 325. 492;
Holaster j ubglobosus^ 157,
492 ; Afarsupites ustudin^
arius. 294, 346 ; Micrast.
cor-angutnum, 301, 329, 492,
518; Micrast. cor-Usttutin-
arium, 306, 327, 335, 492.
518; Hhyn.cuvieri^ 138, 157,

250 317, 323, 492. 533 ;

Ttrehratuhna gracilis 138,

250,315, 324,492,518

Zones of W^hite Chalk of
English Coast : Dr. Arthur
W. Roweon, 289; Gore End
(Birchington) to Kings-
gate, 294 ; Kingsgate to St.
Margaret's Bay, 301 ; St.
Margaret's Bay to Shake-
speare's Cliff, 305 ; Section
in I^ngdon Stairs, 320 ;
Measurements of the Zones
in the Kent Coast, 320 ;
Eastbourne to the Cuck-
nr.ere, 321 ; The Cuckmere
to Seaford Head, 332 ; Meas-
urements at Seaford Head,
336 ; Newhaven to Brighton,
336 ; Measurements of the
Zones in the Sussex Coast,
350 ; Sheets of 6in. Mapsem-
ployed (Ordnance Survey),
350 ; Appendix (a), 353 ;
Appendix (B), 355 ; List of
Fossils ... 359

Zygohatis ... 5

END OF VOLU.ME XVI.

HAYMAN, CHRISTY & LILLY, LTD., II3— II5, FARRINCDON KOAD, E.C.

Vol. XV I.

FEBRUARY, 1899:

Part 1.

PROCEEDINGS

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kmbridgeshire geology to arouse interest when once an enthusiasm for the science has been kindled, and f3bm%
need of a concise hand-book which should clearly describe and explain the leading tacts that have beca BBde
vn....Thc present work is a model of what a country geology should be."

Petrology for Students. An introduction to the Study of Rocks under the Mi

By A^AKKBK, M.A., F.GS., Fellow of St. John's College, Demonstrator in Geology (Petrokgy) n iki
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Natnrt. — *' No better introduction to the study of petrology could be desired than b aSbnied by Mr. Haifai^
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In Preparation,

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Cambridge.

The Prinoinles of Stratigraphieal Geology. By J. E. Mare, M.A„ Fellow of

St. John's College.
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In till* ♦' ElemeniMy G«jlagSc4l Swim" are Hvt «U.
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SBT No, 39t ** MttaJik MimtrAit" contajni »i
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FIllOfT,

•rr No, 27, ^ ^ . ,^

specimens of Earthy Mineral*, indutlinE FIiKir
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SST Mo* 2S, *' fx^UPUw ^tffjtt/* contalnf ao nan>ed
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aCT NOb 3df ** SjdfHttmtary K^kx^" contains 90
named Spcdmem of Sedimenury Rockji. including
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&c. ...... 2m> ed.

V '* Fffttiitt" contains io named Specimen^
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LECTURERS FOR THE WINTER SEASON, 1899-1900.

811 ARTHUR ARNOLD, SIR LAMBERT PLAYFAIR, THE MASTER OF DOWNING
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(Vol.11. Imtkt

Outlines of Vertebrate Palasontology. For Students of Zoology. Bv
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was need of a concise hand>book which should dearly describe and explain the leading facts that have beet
known ...The present work is a model of what a country geology should be."

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The Principles of Stratigraphical Geology. By J. E. Majir, M.A«, Fell

St. John's College.
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will also accord their thanks to tho<e who )
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subject."

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Vol. XVI.

FEBRUARY, 1900.

Parts.

PROCEEDINGS

OF THE

Geologists' Association,

EDITED BY

H. A. ALLEN, F.G.S.

{Authors atone are responsible for the statements
in their respective Papers,)

Contents^

PAGB

I. The Raised Beach and Rubble-Drift at Aldriogton. (lUastrated. By

F. Chafman, A.L.S., F.R.M.S. (Continued) t6c

9. The Pleistocene Deposits of the Ilford and Wanstead District. (Illostrated.)

By Martin A. C. Hinton 271

3. The Pleistocene Noo-Marine Molluscs of Ilford. By A. S. Kbnnard and

B. B. Woodward, F.G S., F.R.M.S aSa

4. Ordinary Meeting and Conversazione, Friday, yrii November, 1899 • sM

5. Ordinary Meeting, FHday, ist December, 1899 988

A. Ordinary Meeting, Friday, 5th January, 1900 288

7. The Zones of the White Chalk of the English Coast. (Illustrated, Plates

VIII-X) By Dr. Arthur Rowe, F.G.S. Part I.— Kewt and Sussex. With
Appendices by Dr. J. W. Gregory, F.G.S., F.Z.S., and Dr. F. L. Kitchin,
M.A, F.G.S. The Cliff Sections by C. Davie<; Sherborn, F.G.S., F.Z S. . S89

LONDON :

UNIVERSITY COLLEGE.

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Itnud Mmrch 19/A, 1900.) [Price is. 6d.

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I{0GKS, FOSSILS, &c.

THEIR NAMES. 'WHAT THEY ARE
AND WHERE THEY ARE FOUND."

In (bit " ElcrnCDtarr Gwlgeical Sa^«'' an five scti,
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27t " Eariky MiMtraiM*" codUins « named
SpediDen^ of Earthy Mincr«U, im:luding Fluor,
Apftlite, Fejspwt Talc, Horablende, &c. 2a. fdi

ilO. 2S,, " Ifnifftu Xockj," contains ao named
Specimeoi of Tj^ieoui^ Volcaniq. and Metimorpbic
Rocki} Lndudmf ObsidiMni TrmchytUt GriLnLte,
Lavs, Biualt, &c* . . > - 2«, Sd<

SKT Mo* 29| "^ SfJimetttfry ffaeij/' contains «5
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{Late Classical Scholar, Corpus Chnsti College, Cambridge),

LECTURERS FOR THE WINTER SEASON, 1899-1900.

811 ARTHUI ARNOLD, SIR LAMBERT PLAYFAIR, THE MASTER OF DOWNING
COLLEGE, THE HEAD MASTER OF CHELTENHAM COLLEGE,

THE MASTER OF WELLINGTON COLLEGE, DEAN FORREST, CANON TRISTRAM,

PROFESSOR 8AYGE, PROFESSOR RAMSAY, DEAN FARRAR,

and PROFESSOR LANCIANL

13-Quinea Rome Tours.

18-Guinea Mediterranean Cruises.

Extended Palestine and Efi^ypt Cruises.

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Centrai Asian Tour (Samarcand, Kerr, and Crimea).

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Woodward, M.A., Assistant Keeper of the Department of Geology- in the British Mnsenm. Demy 8vo.
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in Cambridgeshire geology to arouse interest when once an enthusiasm for the science nas been kindled, and there
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known.. ..The present work is a model of what a country geology should be."

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Cambridge.

The Prinoiples of Stratigraphical Geology. By J. E. Marr, M.A„ Fellow of

St. John's College.

By
With lUnstra-

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New Book by Sir Archibald OeiMe.

THE FOUNDERS~OF GEOLOGY.

I By Sir Archibald Geikib, F.R.S., Hon- D.CL.

Oxf., Hon. D.Sc.Camb., Dubl., Hon. LL.D. Edin.,
I St. And.. Director-General of the Geological Survey

of Great Britain and Ireland. Extra Crown 8vo.

Ss. net.

I NA TUR £*.— " Geologists owe a debt of gratitude
to Mrs. George Huntington Williams, who founded
the lectureship in Memory of her dLstingulthed and
much-lamented husband, the late Professor of
Geology in the Johns Hopkins University. They
will also accord their thanks to tho«e who selected
the first lecturer, and to him for h» choice of a
subject."

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rmimjrrmpble Addresf: "CeLBCIA." LONDON. _^_^^^^^^^_^_

Vol. XVL

MAY, 1900.

Part 7.

PROCEEDINGS

OF THE

Geologists' Association.

EDITED BY

H. A. ALLEN, F.G.S.

{Authors alone are responsible for the statements
in their respective Papers,)

I. The Natural History of Phoaphatic Deposits. Dy J. T. H. Teall, M.A.,

F.R.S 369

a. Ordinary Meeting, Febniarj* and, 1500 387

3. Ordinary Meeting, March and, 1900 •...-.... 387

4. Annual General Meeting, February 2nd, 1900 383

5. Wind-worn Pehhles in the British Isles. By F. A. Bather. M.A., F.G.S.,

(Illustraied, Plate XI.) 396

6. Ordinary Meeting, May 4th, 1900 430

7. A New Rhctic Section at Bristol. By W. H. Wickes .... 431

8. Visit to the Museum of the Geological Society, February' loth, 1900 . 433

LONDON :

UNIVERSITY COLLEGE.

EDWARD STANFORD, 26 and 27,Cockspur Street,Charing Cross.S.W.

Issued Jun€ Totk, 1900. 1 [Price w. 6d.

M^MiM. OMIIt-nr A UkLV. ^"9.. MlNTIIIt PAMINOOO*! M.. CO.

AO emammUeMtioDs

refpaetlnff advertltemenU to be i«aX v^lir.TBSS^ikl&^lARS^E^Jb
16, Hontaffue Ptojce, Um4oTi«'V.C« -.

HOGKS, FOSSILS, &c.

THEIR NAMES. ►'WHAT THEV ARE
AND WHERE THEY ARE FOUND/'

In thU "Klementary Gr%>!oi;icil Sefles*' are five seiH,
each K( cone^jniiig 70 nsinied and located ApcciEncns^
with dsfcnpiK'c hoici.. Post fr^t, Bm*

SET NO1 2fl| ^* Mifai/k Miiirmh" contAint ^1=^
nain«i:I SpecimeiiFi of MciaUic Mincrdhand Orc^^ in
which ihe principal group* are repTcsenied^ includ
itig Ores uf cupper, trun, i^ad, th\Ci iiHi ^c< 3^ ^^'

9ET No> 27, *' Earthf ittM^r^h" coniaiji^ ?q n^nied
Spt^tmciis of EjuiAy MincFatsi, includiniF; Fluor,
Apaeilc, rdipar, TaIc, HDrnblcndvi &c« 3Si Od*

ftET No* 28a *' /jpt^etti JUtK^s/' cantAin^ tq named
Specimens of Ijjntiju^^ ytUtanic* and Mc^tamorvhi1:
Rockfif including; Otrtidlanf Trachyte, Grajute.
Lava, HasAh, &c. ^ ^ ^ 2«. Otf.

No* 20| *^* Stiff fttintAry ^m-JC-j/' t^nnLAin^ tc
named Spcvimcn* of Sctlimeniari" Rocks i Molding
Ctag, GauUt Qolilc^ Lias, Limei^tone, Sand-itomr,
&c. 2«. ed.

No 30f ** F^osfih,'* cnnlninft jd namwl ^prcimen^
of BriEiiih and t^her Fm-^ih, incVLjdm>; rxamplK
frrjm Crag, Evcenc, G:LLdH O-jliiCt Carbon ifcrou*

&c , . 2b« 6d:

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A GREAT GEOLOGIST.

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LIFE AND LETTERS OF

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WRITTEN AND EDITED BY HIS WIFE.
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HOGKS, FOSSILS, &c.

THEIR NAMES. "WHAT THEY ARE
AND WHERE THEY ARE FOUNO.'^

In this "Elemcnliuy Gcolopcai Series'' are fii^e i^itt^,
ea£h KcL cQnuiniiig 20 nnnsrd aod located Sipecimcn^^
with dcscriptii-e noiein, Pait freSt 3*>

SET NOi 28f "iUfta/irc Afittftys/i" con(ab5 so
aajTied Specimeufi af Metallic MintraUanHj OrifK, in
which the principal groups nre repref^ntrd, inL'lTiJ'
ing Ores Drcoppcr, ir^i), lead, liiK, tin, &c^ 3tt» tfdi

SET MOi 3:T| '* Earthy Umtrn.it " coittains jo n;ini«ii
Spediii*:n& of Eartby MJnejrfU^ incluOing riuor,
Aps^titc, FelipaTi Takf Hornbleiule, i^c- ^v> Odi

SET No* 2S| '' ff^mtaux Rocks t*' €oni s,la% so nrtmed
Specttnensfif Igneous VolcratiiCt anrj Mctajnorphii:
Kock^r indudme Obfidiaa, Trachyte, Granar,
Lava, Basal I, kc. , . . 2*. Sd.

SET No* 29| ^^ StdtmiKtOrfy Ei^ks^' conlfliri!! so
nimieil Specimens of ftedimenLiry JKoct^^ Irtdudiiif^
Crafft GftiiUt OoUtCi Lici^, LLmfiione, Sind$irttn«.
&c. ...*.. 2«* 6cf.

SET No SOf *' Fottih,"' cDnininnso njune*! Spccimf^ni
of Uritinh and ^iher Fitt^i^iljc, inLli|dJTi|| ^Kamplcii
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A GREAT GEOLOGIST.

AT ALL LIBRARIES.

LIFE AND LETTERS OF

SIR JOSEPH PRESTWICH,

WRITTEN AND EDITED BY HIS WIFE.
WITH PORTRAITS AND OTHER ILLUSTRATIONS.

Demy Svo, 21s.

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(^LaU Classical Sc/iclar^ Corpus Chnsti Colhge^ Cambridge').

LECTURERS FOR THE WINTER SEASON, 1809-1900.

SIR ARTHUR ARNOLD, SIR LAMBERT PLAYFAIR, THE MASTER OF DOWNINC
COLLEGE, THE HEAD MASTER OF CHELTEHHAM COLLEGE,

THE MASTER OF WELLINGTON COLLEGE, DEAN FORREST, CANON TRISTRAM,

PROFESSOR SAYCE, PROFESSOR RAMSAY, DEAN FARRAR,

and PROFESSOR LAHCIAHI.

13-Guinea Rome Tours.

18-Guinea Mediterranean Cruises.

Extended Palestine and E^ypt Cruises.

Biarritz, Lourdes, and Pyrenees Tour.

IMadrid, Seville, and Granada Tour.

Venice, Florence, and Italian Lakes Tour.

Central Asian Tour (Samarcand, Merr, and Crimea).

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Cycling: Tours in the United Kinfi^dom,
France, Switzerland, &c.

Full particulars, with Plans of the Steamers, on application to the
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Cam&ri^0e Datura! Sctence riDanuald.

BIOLOGICAL SERIES. NEW VOLUMES.

General Editor: A. E. Shipley, M.A., Fellow and Tutor of Christ's Collq

Fossil Plants. A Manual for Stulents of Botany and Geolofry, By A. C. Si
M.A., F.R.S., St. John's College. In 2 Vols. Vol. I. Demy Bvo, With numerous Illustnoioi

[Vol. II. /HtA

OatUnes of Vertebrate Pateontology. For Students of Zoology. By
Woodward, M. A., Assistant Keeper of the Department of Geology in the British Museum. A
With numerous Illastrations. i4ir.

Elementary Palnontoloffy— Invertebrate. By Henry Woods, M.A.,

Crown 8vo. Second Edition, Revised and enlarged with additional Illustrations. 6r.

GEOLOGICAL SERIES.
Handbook to the Geology of Cambridgesliire. For the use of Student

F. R. CowpER Reed, M.A., F.G!S., Assistant to the Woodwardian Professor of Geology. With
tions. Crown 8vo. 7*. 6rf.

ATa/irrip.— "The geology of Cambridgeshire possesses a special interest for manv students....There
in Cambridgeshire geology to arouse interest when once an enthusiasm for the science has been kindled, ai
was need of a concise hand-book which should Jearly describe and explain the leading facts that ha\'e be*
known.. ..The present work is a model of what a country geology should be."

Petrology for Students. An introduction to the Study of Rocks under the Mien
By A. Harkbr, M.A., F.G S., Fellow of St. John's College, Demonstrator in Geology (Petrology
University of Cambridge. Second Edition, revised. Crown 8vo. 7*. td.

Nature.—'* No better introduction to the study of petrology could be desired than is afforded by Mr I
volume."

In Preparation.
Crystallography. By W. J. Lewis, M.A., Professor of Mineralogy in the Univei

Cambridge.

The Principles of Stratigraphical Geology. By J. £. Marr, M.A., Pel

St. John's College. ■

London : C. J. CLAY & SONS, Cambridge University Press Warehouse, Ave Maria

JAMES R. GREGORY & CO.,

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New Book by Sir Archibald Oeil

THE FOUNDErToF CEOL

By Sir Archibald Geikie, F.R.S., Hon.
Oxf., Hon. p.Sc.Camb., Dubl., Hon. LL.I
St. And., Director-General of the Geoloeica
of Great Britain and Ireland. Extra Cro
SS. net.

NA TURE.—" Geologists owe a debt of g
to Mrs. George Huntington Williams, who
the lectureship in Memory of her distinguis
much-lamented husband, the late^ Profc
Geology in the Johns Hopkins University
will also accord their thanks to tho<e who
the first lecturer, and to him for his choi
.subject."

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Tables ma^ \>« \iW!As!^ V&. «a^v&sa<

Tafrrmoble AMr»m "CBLBCIA,» LONDON.

¥aL XVL

JULY, 1900.

Part I

PROCEEDINGS

OF THE

Geologists' Association,

EDITED BY

H. A. ALLEN, F.G.S.

{Authors alone are responsible for the statements
in their respective Papers.)

PAGB

I. Excursion to Newton Abbot, Chudleigh, Dartmoor, and Torquay.

(Illustrated, Plate XII.) Easter, 1900 435

a. Excursion to Wimbledon and Kingston, April 38th, 1900 443

3. Visit to the British Museum (Natural History), March 17th, 1900 445

4. Excursion to Hitchin and Arlesey, May 5th, 1900 446

5. Excursion to Hertingfordbury, Bayford. and Brickenden Qreen, May

i9lh, 1900 447

LONDON :

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EDWARD STANFORD, 26 and 27,Cockspur Street, Charing Cross.S.W.

tsnud July t6/A, 1900.) [Pkicb i«. 6d.

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16. fUmtasiM PlaM, LmiAo», ^.O*

HOCKS, FOSSILS, &c.

THEIR NAMES. **WHAT THEY ARE
AND WHERE THEY ARE FOUND/'

In thU " £lcTneiita:ry Geol«tcal Series** are fi« s*l»,
eftcb sti dontuniitg to named aad located kpccLmen^
with descriptive notes. P&^t fpttt 3«>

UT NOi» 201 ** 3i£ta.tiic Miitfrmli," contains mo
named Specnnetiit of Mc^utUic hUnenUand Ores, in
wbjch ihcprit^dpjil gmop*are_reprrtenied, mclud-
itig OitA of coppcfp iTOBf Ic^f zinc, tLdi| Slc* 2fti 0<li

ftFT KCK 27 1 ^*- Ettrtky J^indm-iM," cantiuniTa named
Specimt^ns. of Earthy MinermUf inclmJlag Fluor.
Apatiie, Felipar. Tak« Hornblende, &c. 2«i tt<li

9KT NOf 2ft| *^ fgwttffMt Sxi^," ccfitaiat v> named
SpsmenB of l^eoiu^ Volcanic, Jind MetiMtnorf4iic
tlodkxi, Lncludmg: Obftidiui, Trftchyic, Oratiite,
Lm, Buak, &c. » 2«« ttf.

0CT NOw 9 Of "" SffiffttrHtitry /Pjcki,'* contairiB ^
nx'vmed ^Specimens of Sedimcoiary Roclbi, including
Crag, Cauii, Ooliie^ LiiUt Limestone, Sand ^ one,
&d. ...... 2«, 6d.

ftCT Ho 30| '*/'#rfi'irf'*cofllaii]Saonam«l5peciinenJi
of British afld other Fonilt, Lnclisding examples
from Crag, Eocene , Giuiki Ootite, Carboniferous,

&c. ...... . 2«. a^ .

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A GREAT GEOLOGIST.

AT ALL LIBRARIES.

LIFE AND LETTERS OF

SIR JOSEPH PRESTWia

MJl^ D.CL^ FJl^.
yotmetli2 profeeaot ot (5coloQ^ in tbe tlnfY^etdfti^ ot 9itot5.

WRITTEN AND EDITED BY HIS WIFE.
WITH PORTRAITS AND OTHER ILLUSTRATIONS

Demy Svo, 21ft,

/ WILLIAM BUCKVrOOD & SQHS. E&ltibar^h aod Uodoi

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ORGANIZED BY

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(^Fellow of the Medical Society of London) ; and

J. T. WOOLRYCH PEROWNE, M.A.

(Za// Ciasstcai Scholar^ Corpus Chrtsti ColUge^ Cambridge),

LECTURERS FOR THE WINTER SEASON, 1899-1900.

SIB ARTHUR ARNOLD, SIR LAMBERT PLAYFAIR, THE MASTER OF DOWNING
COLLEGE, THE HEAD MASTER OF CHELTENHAM COLLEGE,

THE MASTER OF WELLIHCTON COLLEGE, DEAN FORREST, CANON TRISTRAM,

PROFESSOR SAYCE, PROFESSOR RAMSAY, DEAN FARRAR,

and PROFESSOR LANCIANI.

13-Guinea Rome Tours.

18-Guinea Mediterranean Cruises.

Extended Palestine and Efi^ypt Cruises.

Biarritz, Lourdes, and Pyrenees Tour.

■Madrid, Seviiie, and Granada Tour.

Venice, Florence, and Italian Lakes Tour.

Central Asian Tour (SamarcaBd, lerr, and Crimea).

Chamounix Skating AToboffffaninff Parties.

British Empire Cruise (India, tbe Cape, Australasia).

Cyciinff Tours in the United Kln^rdom,
France, Switzerland, &c.

Full particulars, with Plans of the Steamers, on application to the
Secretary, 5, Endsleitrh Qardens, Buston, London, N.W.

Cambriboe Vlatural Qclcnce nDanual0.

BIOLOGICAL SERIES. NEW VOLUMES.

Genenl Editor: A. E. Shipley, M.A., Fellow and Tutor of Christ's College.

Fossil Plants. A Manual for Students of Botany and Geology. By A. C. SbwaI
M.A., F.R.S., St. John's College. In 3 Vols. Vol. I. Demy 8vo. With numeroas Illustrations. 1

lVol.II. JntJUPn

Outlines of Vertebrate Fateontology. For Students of Zoology. By A.
Woodward, M.A., Assistant Keeper of the Department of Geology in the British Museum. Demy 8
With numerous Illustrations. 14X.

Elementary FalaBontoloffy—InTerteteate. By Henry Woods, M.A., F.G

Crown Svo. Second Edition, Kevised and enlarged with additional Illustrations. 6j.

GEOLOGICAL SERIES.
Handbook to the Geology of Cambridgeshire. For the use of Students.

F. R. CowpBR Reed, M.A., F.G/S., Assistant to the Woodwardian Professor of Geology. With lUusi

tions. Crown 8vo. 7*. 6d.

Nature, — " The geology of Cambridgeshire possesses a special interest for many students....There is m\

in Cambridgeshire geology to arouse interest when once an enthusiasm for the science has been kindled, and th

was need ot a concise hand-book which should dearly describe and explain the leading facts that have been mx

known.. ..The present work is a model of what a country geology should be."

Fetrology for Students. An introduction to the Study of Rocks under the Microsco]
By A. Harker, M.A., F.G S., Fellow of St. John's College, Demonstrator in Geology (Petrology) in
University of Cambridge. Second Edition, revised. Crown Svo. js.Sd,

Naturt, — " No better introduction to the study of petrology could be desired than is afforded by Mr Harki
volume."

In Preparation,

Crystallography. By W. J. Lewis, M.A., Professor of Mineralogy in the University
Cambridge.

The Frinciples of Stratigraphieal Geology. By J. E. Mark, M.A., Fellow

St. John's College.
London : C. J. CLAY & SONS, Cambridge University Press Warehouse, Ave Maria Lai

JAMES R. GREGORY & CO.,

/CineralogiBtdt Sic,

KELSO PLACE, KENSINGTON, W.

CHOICE MINERALS AND FOSHILS,

NEW ROCK SPECIMENS.

NEW AND LONG LIST OF SINGLE MINERALS.

Price 2cl.

AVw Catahgnes Free 0/ Collections ^ Rock Sections^ etc.

A few minutes from Natural History Museum, Science

Schools, South Kensington, High Street, and

Gloucester Road Stations.

Specimens, Collections, Appliances, etc.

New Book l>y Sir Archllwld Qelkie.

THE FOUNDERS~OF GEOLOG

By Sir Archibald Geikir, F.R.S., Hon. D.C
Oxf., Hon. D.Sc.Camb., Dubl., Hon. LL.D. Ed
St. And., Director-General of the Geolo^cal Sur
I of Great Britain and Ireland. Extra Crown I
es. net.

NA TURE. — •* Geologists owe a debt of gratir
to Mrs. George^ Huntington Williams, who foun*
the lectureship in Memory of her distinguished \
much-lamented husband, the late^ Professor
Geology in the Johns Hopkins University. Tl
will also accord their thanks to tho«e who selec
the first lecturer, and to him for his choice o<
.subject."

MACMILLAN A Co., Ltd., LONDON.

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*Ji—ra»Ma AMrmMM: "CBLBCIA." LONDON.

Vol. XVL

AUGUST, 1900.

Part 9.

PROCEEDINGS

OF THE

Geologists' Association,

EDITED BY

H A. ALLEN, F.G.S.

(Authors alone are responsible for the statements
in their respective Papers.)

C^OXiUXiU^

•r. Notes on the Geology of the Bnclith Lake District. By J. E. Mass,
M.A., F.ILS. (lUnstrated)

9. Zonal Features of the Chalk Pits in the Rochester, Oravesend, and
Croydon Areas. By G. E. Dibuby, F.G.S^ with sn Appendix on a Bone
from the ChsDc of Coztoo. By E. T. Nbwton, F.R.S. (iUottnUed) .

3. BsKursion to Bastbonme and Sesford, If ay sfith, igoo

• Adpancs copi$i of thit paptr w*r$ issusd, July MJk, to Mtmbin taking
part i» tks Lon% Excunkm.

LONDON :

UNIVERSITY COLLEGE.

EDWARD STANFORD, 26 and 27,Cockspur Street, Charing Cross.S.W.

Itsmd StpUmher 4/*, 190a] (PaiCB is. 6d.

449

484

%. OMwrr * utkr. i*^. nmrrtn

IBi

advtrtismiiinU to b% ma\ \Alte. T&MLlSk ^«MS«lMSi

ROCKS, FOSSILS, &c.

THEIR NAMES, **WHAT THEY ARE
AND WHERE THEY ARE FOUND.

In this " Elementary Geolockal Scries" are five sei>
«ndi sec containing ao named and located <promrn».
with descnpcivc notes. Foit frm, Ss.

Mo. SSy ** MetMJiic MtMermlt^" contains >
named Specimeus of McialUc Minetals and Or», i:
which the Drindpal groaps are represented, includ-
ing Ores of copper, iron, lead, zinc, tin, &c 2s> 6dL

. . 27t ** Eartkr Mhurmis" contuns to named
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Apatite, Febpar, Talc, Hornblende, &c la. 6«l.

MOb 2St " fgne»ut R0cks" contains ao named
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Lava, Basak, &c . . . . 2s. 6d.

SBT Mo. 29f ** SeJfmentmry R^cks" contains ac
named Specimen<« of 5>edimentary Rocks, includtnc
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ftc 2s. 6tf .

» 30f '* Fossilst" contains 20 named Spedmen»
of British and other Fossils, including example>
from Crag, Eocene, Gauli, Oolite, Carboniferous,

ftc 2s. 6d.

Postas* ^ sacli sot 6<f,

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A GREAT GEOLOGIST.

AT ALL LIBRARIES.

LIFE AND LETTERS OF

SIR JOSEPH PRESTWICH,

M*A^ D^CU, F.R*S*

Jormcrlg professor of (BcoIo^B In tbc Tflnipcreiti? of ^rfor^.
Written and Edited by His Wife.

W^ITH portraits AND OTHER ILLUSTRATIONS.

Demy 8vo, 21s.

WILLIAM BLACKWOOT> & SQ^S> Edlabargh and London.

CO-OPERATIVE
EDUCATIONAL TRAVEL

ORGANIZED BY

HENRY S. LUNN, M.D., B.Ch., F.R.G.S.

(^Fellow of the Medical Society of London) ; and

J. T. WOOLRYCH PEROWNE, M.A.

(^Late Classical Scholar^ Corpus Chrtsti College^ Cambridge').

LECTURERS FOR THE WINTER SEASON, 1899-1900.

SIR ARTHUR ARNOLD, SIR LAMBERT PLAYFAIR, THE MASTER OF DOWNING
COLLEGE, THE HEAD MASTER OF CHELTEHHAM COLLEGE,

THE MASTER OF WELLIHCTON COLLEGE, DEAN FORREST, CANON TRISTRAM,

PROFESSOR SAYCE, PROFESSOR RAMSAY, DEAN FARRAR,

and PROFESSOR LAHCIANI.

13-Guinea Rome Tours.

18-Quinea Mediterranean Cruises.

Extended Paiestine and Efirypt Cruises.

Biarritz, Lourdes, and Pyrenees Tour.

Madrid, Seviiie, and Granada Tour.

Venice, Fiorence, and italian i-alces Tour.

Centrai Asian Tour (Samarcand, Men, and Crimea).

Chamounix Slcatinff &Toboffffaninff Parties.

British Empire Cruise (India, ilie Cape, Australasia).

Cyciinff Tours In tlie United Kingdom,
France, Switzerland, &c.

full particulars, with Plans of the Steamers, on application to the
Secretary, 5, Endsleltrh Gardens, Euston, London^ N.W.

Cambriboe Vlatural Science nDanuate.

_, BIOLOGICAL SERIES. NEW VOLUMES.

General Editor: A. £. Shiplbv, M.A., Fellow and Tutor of Chriit's College.

Fossil Plants. A Maoual for Stulents of BoUny and Geology. By A. C SlWARD,
M.A., F.R.S., St. John's College. In a lipb. Vol. I. Demy Svo. With namcroiis Ilhistnuioas. itf.

^ (VoLII. imtJktPrw.

OutlinSS of Verteteate FateontolOgy. For Students of Zoology. By A. S.
WooDWABD, M. A., Assisiant Keeper of the Denmmcnt of Geology id the British Museani. Demy 8vt>.
With numerous lUustrations. 14s,

Slomentary PalaBontoloffy—InTertoteate. By Hbnry Woods, M.A., F.G.S.

Crown 8vo. Sicond EditioM, Revised and enlarged with additional Illustratioos. 6f .

GEOLOGICAL SERIES.
Handbook to the Geology of Cambridgesliire. For the use of Students. By

F. R. CowpRB Rrbd, M.A., F.g!S., Assistant to the Woodwardian Professor of Geolo^. Wil^ lUostrm-
tioas. Crown 8ro. 7«. td.

Nature, — **Thegeology of Cambridgeshire possesses a special interest for manv sludcnts....Tbcn is mndi
in Cambridgeshire geology to arouse interest when once an enthusiasm for the scieiice has been Idndled. and there
was need of a concise hand<book which should dearly describe and excJain the leading facts that have oeen made
known.. ..The present work is a model of what a country geology should be."

PetrolOffy for Students. An introduction to the Study of Rocks under the Microscope.
By AnHAKKBK, M.A., F.G S., Felkyw of St. John's College, Demonstrator in Geok)gy (Petrology) in tht
University of Cambridge. Second Edition, revised. Crown 8vo. ^t,6d,

Nmimrv,-:-" No better introduction to the study of petrology could be desired than is affoidad by3Ir Harkcr^s
volume."

In Pr^raHan.

Crystallography. By W. J. Lbwis, M.A., Professor of Mineralogy in the University of
Cambridge.

The Principles of Stratigraphioal Geology. By J. E. Marr, M.A., Fellow of

St. John's College.
London : C. J. CLAY & SONS, Cambridge University Press Warehouse, Ave Maiia Lane.

JAMES R. GREGORY & CO.,

/Cfneralogists, &c.,

KELSO PLACE^ KENSINGTON, W.

CHOICE MINERALS AMD POSSILS.

MEW ROCK SPECIMENS.

MEW AND LONG UST OF SINGLE MINERALS,

Prictt 2d.

AVw CaitUogues Frtt ^Collections^ Rock Sections^ etc

A few minutes from Natural History Museum, Science

Schools, South Kensington, High Street, and

Gloucester Road Stations.

SraCIMBNS, COLLKCTIONS, APPLIANCES, etc.

New Book by Sir ArcUbeld Osikto.

THE FOUNDERS'OF GEOLOGY.

By Sir Archibald Gbikik, F.R.S., Hon. D.CL.
Oxf., Hon. D.ScCamb., Dubl., Hon. LL.D. Edin.,
St. And., Director-General of the Geological Sanfcy
of Great Britadn and Ireland. Elxtra Crown 8vo.
Oft. net.

NA TURE.—** Geologisuowe a debt of gratitude
to Mrs. George Huntington Williams, who founded
the lectureship in Memory of her duuinguishcd and
much'lamentcxl husband, the late Professor ol
Geology in the Johns Hopkins University. They
will also accord their thanks to tho<e who selected
the first lecturer, and to him for his choice of a
subject."

MACMILLAN A Co., Ltd., LONDON^

HOTEL CECIL, LONDON.

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Tables may \m ^mmYlaAl Vtv «&:^«XL<«a,

'mUfnaUe AMr»su! "CBLBCIA." LONDON.

Vol. XVI.

NOVEMBER, 1900.

Part 10.

PROCEEDINGS

OF THE

Geologists' Association,

EDITED BY

A . ALLEN, F . G . S .

{Authors alone are responsible for the statements
in their respective Papers.)

ContentB*

X.
3.

3-
4.

5-
6.

7-
8.
9-
xo.

XX.
X2.

13-
M-
X5-

1900. (Illustrated.)
e i6th, 1900

4tK

1900

Excursion to Boxmoor, May i3th, 1900. (Illustr.ited.)

Excursion to Malvern and District, Whitsuntide, June and,

Excursion to Caterham, Godstone, and Tilburstow, J

Excursion to Guildford, June 23rd, 1900

Excursion to Silchester, June 30th, 1900

Excursion to Kettering and Thrapston, July 7th, 1900

Excursion to Purley, Kenley, and ^Vhyteleafe, July i

Excursion to \Vinchfield and Hook, July 21st, 1900

Excursion to Grove Park, July 2Sth, 1900 .

Excursion to Netley Heath, August nth, 1900 .

Lone Excursion to Keswick, August 20th to August 25ih,

Plates xiii, xiv.)

Excursion to Strood and Hailing, Septemljer 8th, 1900
Excursion to Orpington, September 22nd, 1000 .

Ordinary Meeting, June i>t, 1000

Ordinary Meeting, July 6th, 1900

The Index and Title Papes to Vol. XVI will be issued with Part I
of Vol. XVII.

1900.

(Illus;

•aied.

PACK
501
503
510

5"
5x3
516
5«8

5»9
533

5*4

5»6
53a
533
535
535

LONDON :

UNIVERSITY COLLEGE.

EDWARD STANFORD, 26 and 27,Cockspur Street.Charing Cross.S.W.

Issued Xovemher 2ith, 1900.]

[Price is (d.

MVMAN. OHIItTV A LH.LY. I "B.. MIN'

MiNOOOw na. B.a

AU communications respecting advertisements to\ie ««tvX XA^T.T^KS^t&^^ikMSVU
15, Montague Place, London, Vi.C.

I{0GKS, FOSSILS, &c.

THEIR NAMES, -WHAT THEY ARE
AND WHERE THEY ARE FOUND/

ea-li ?ici can mi 11 ui^ /.^ iM'-'-rtt a^.i li- :tnni' -.iKumcMx.
SET NO. 29i '* .1 //*«/;?> .'Aii'-n-i:-/ iiiianin^ r-

in^ On; "4 1 tff.- J) i\ irr , i rii 'H , El a ' . Anc, t in , r^v . 2V- C<l-

SET NOb ^Tf" f^r^I^tfn■ .*//"■' -i^/j," L.i'it^.in-i 7fj n:imMl
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A|ia r 1 1 r, It] ^p ^ I , T;i El . ] f i?riL ' Ivml v. ^i , 2a. 9d.

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kock^p irit'liultnj£ t)li-(Jl_\, TpkUrli^Li:, cir.iiilLH;
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ilrziti ^ i I :iu1 [ ,, f 3 <1 lie, ] .izi -, lAm e->*! ^ hi jc, ShV ^'1>i ^ ■ ' > ^
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from Ur.ij;, KuccOf i t^i:inl,, OjIi^;, triJ,i"'i'.'iiif'"tini-.

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The abutfc 100 Spnimem af Minerah, po>t /fff,

NEW BET, Prrci.'iif X/.^ir^:.

va.|ir fil^^

3a.

COX Xr CO., New O^rord Street, London.

A GREAT GEOLOGIST.

AT ALL LIBRARIES.

LIFE AND LETTERS OF

SIR JOSEPH PRESTWICh

M.A-, D.CX., F*R.S.

Jornicrlv) professor of Gcoloax} in tbc tliiivcrsiti? of Oi:for&.

Written and Ldited by His Wife.

with portraits and other illustrations

Demy 8vO| 218.

WILLIAM BLACKWOOD Si SQ^'s, ^ftlvateva^Jv and London

I ■

CO-OPERATIVE
EDUCATIONAL TRAVEL

ORGANIZED BY

HENRY S. LUNN, M.D., B.Ch., F.R.Q.S.

(^Fello-iu of the Medical Society of London) ; and

J. T. WOOLRYCH PEROWNE. M.A.

(^Late Classical Scholar^ Corpus C/iristi College^ Cambridge').

LECTURERS FOR THE WINTER SEASON, 1899-1900.

SIR ARTHUR ARNOLD, SIR LAMBERT PLAYFAIR, THE MASTER OF DOWNING
COLLEGE, THE HEAD MASTER OF CHELTENHAM COLLEGE,

THE MASTER OF WELLINGTON COLLEGE, DEAN FORREST, CANON TRISTRAM,

PROFESSOR SAYCE, PROFESSOR RAMSAY, DEAN FARRAR,

and PROFESSOR LANCIANI.

13-Guinea Rome Tours.

18-Guinea Mediterranean Cruises.

Extended Palestine and Efi^ypt Cruises.

Biarritz, Lourdes, and Pyrenees Tour.

IMadrid, Seviiie, and Granada Tour.

Venice, Fiorenoe, and Itaiian Lakes Tour.

Centrai Asian Tour (Samarcand, Merv, and Crimea).

Chamounix Skatin^^ ATobosreraning: Parties.

British Empire Cruise (India, the Cape, Anstralasia).

Cycling: Tours in tiie United Kingrdom,
France, Switzerland, &c.

Full particulars, with Plans of the Steamers, on application to the
Secretary, 5, Endsleigh Gardens, Euston, London, HAN.

Cambribflc natural Sctcncc flDanuate.

BIOLOGICAL SERIES. NEW VOLUMES.

General Editor: A. E. Shipley, M.A., Fellow and Tutor of Christ's College.

Fossil Plants. A Manual for Students of Botany and Geology. By A. C. Seward,
M.A., F.R.S., St. John's College. In 2 Vols. Vol. I. Demy 8vo. With numerous Illustrations, lar.

[Vol. II. InthePrtss,

Outlines of Vertebrate PalsBontology. For Students of Zoology. By A. S.

Woodward, M.A., Assistant Keeper of the Department of Geology in the British Moiieum. Demy 8vo.
With numerous Illustrations. 14^.

Elementary PalaBontoloffy— Invertebrate. By Henry Woods, M.A., F.G.S.

Crown 8vo. Second Edition. Kevised and enlarged with additional Illustrations. €s.

GEOLOGICAL SERIES.

>gy <

F. R. CowpBR Reed, M.A., F.g!S., Assistant to the Woodwardian Professor of Geology,
tions. Crown 8vo. Tt. 6d.

Nature, — "The geology of Cambridgeshire possesses a special interest for many student*.... There is much
in Cambridgeshire geology to arouse interest when once an enthusiasm for the science has been kindled, and there
was need of a concise hand-book which should clearly describe and explain the leading facts that have been made

Handbook to the Geology of Cambridgesliire. For the use of Students. By

ofessor of Geology. With Illus

Tor many student*.... There is m
science nas been kindled, and tl
. tcplain the ' "'

known. ...The present work is a model of what a country geology should be."

Petrology for Students. An introduction to the Study of Rocks under the Microscope.
By A. Hakker, M.A., F.G S., Fellow of St. John's College, Demonstrator in Geology (Petrology) in the
Uni\ersity of Cambridge. Second Edition, revised. Crown 8 vo. js. 6d,

Nature. — " No better introduction to the study of petrology could be desired than is afforded by Mr Harker's
volume,"

In Preparation.

Crystallography. By W. J. Lewis, M.A., Professor of Mineralogy in the University of
Cambridge.

The Principles of Stratigraphical Geology. By J. £. Marr, M.A,, Fellow of

St. John's College,
London : C. J-. CLAY & SONS, Cambridge University Press Warehouse, Ave Maria Lane.

JAMES R. GREGORY & CO.,

KELSO PLACE, KENSINGTON, W.

CHOICE MINERALS AND FOSHILS.

NEW ROCK SPECIMENS.

NEW AND LONG UST OF SINGLE MINERALS.

Price 2cl.

, Ve7u Catalogues Free 0/ Collections^ Rock Sections^ etc.

^ few minutes from Natural History Museum, Science

Schools, South Kensington, High .Street, and

Gloucester Road Stations.

Specimens, Collections, Ajmliances, etc.

New Book by Sir Archibald Qeikie.

THE FOUNOERS~OF GEOLOGY.

By .Sir Archibald Geikie, F.R.S., Hon. D.CL.
Oxf., Hon. U.Sc.Camb., Dubl.. Hon. LL.D. EtUn.,
St. And., Director-General of the (ieological Survey
of Great Britain and Ireland. Extra Crown Svo.
69. net.

NA TURE. — ** Geolojjisls owe a debt of gratitude
to Mrs. Cieorge Huntington Williams, who founded
the lectureship in Memory of her distinguished and
much-Uunented husband, the late Professor of
(icology in the Johns Hopkins University. They
will also accord their thanks to tho«e who sclented
the first lecturer, and to him for his choice of a
subject."

MACIMILLAN A Co., Ltd., LONDON.

HOTEL CECIL, LONDON,

Tl\e niost Fashioriable and Popular l(otel iq Europe.

MAGNIFICENT SUITES OF ROOMS for
PUBLiO AMD PRIVATE BANQUETS, RECEPTIONS, «o.

THE HOTEL ^ECnT^RESTAURANT.

/ UNEQUALLED CUISINe AND MODERATE CHARGES.

Tables may \>e 'boQi\Le^ Nxk. «A^%(v<&%.

•raoA/c Address: "CELBC/A." LONDON.

4998;

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