s *uW iiiH mx if.^el QE. W)5 •F79 13 15 (Qortiell Ininctatttj ffiihrarg Jltljaca, £iem fork BOUGHT WITH THE INCOME OF THE SAGE ENDOWMENT FUND THE GIFT OF HENRY W. SAGE 1891 Cornell University Library QE 262.W5F79 1915 The geology of the country between Whitb 3 1924 004 550 301 Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924004550301 MEMOIRS OF THE GEOLOGICAL SURVEY. ENGLAND AND WALES. EXPLANATION OF QUARTER SHEETS 95 N.W. AND 104 S.E. (NEW SERIES 35 AND 44.) THE GEOLOGY OF THE COUNTRY BETWEEN WHITBY AND SCARBOROUGH. BY J. FOX-STRANGWAYS, F.G.S., and G. BARROW, F.G.S. 8ECOND EDITION. WITH A CHAPTEK ON THE PAL.EONTOLOGICAL CLASSIFICATION OF THE: LOCAL JURASSIC ROCKS BY S. S. BUCKMAN, F.G.S. PUBLISHED BT ORDER OF THE LORDS COMMISSIONERS OF HIS MAJESTY'S TREASURY. LONDON: PRINTED UNDER THE AUTHORITY OP HIS MAJESTY'S STATIONERY OFFICE By JAS. TRUSCOTT and SON, Ltd., Cannon Street, E.C. And to be purchased from E. STANFORD, Ltd., 12, 13 and 14, Long Acbb, London, W.C. ; W and A. K. JOHNSTON, Ltd., ?, St. Andrew Square, Edinburgh ; HODGES, FIGGIS and Co., Ltd., 104, Grafton Street, Dublin. From any Agent for the sale of Oninance Survey Maps : or through any Bookseller, from T. FISHE R UNWIN, Limited, 1 , Adelphi Terrace, London, W.C, who is the Wholesale Agent to the Trade outside the County of London, 1915. Price 2s. 6d. GEOLOGICAL SURVEY OF ENGLAND AND WALES, AND MUSEUM OF PRACTICAL GEOLOGY. (Office : 28, Jebmyn Stbbbt, London, S.W.) LIST OF PUBLICATIONS. The publications include Maps, Memoirs, Museum Catalogues, Catalogue of Photographs, Guides, &c. A complete list can be obtained from the Ordnance Survey Office, Southampton, price 6d- lne maps ana. Memoirs can be obtained from the Ordnance Survey, or from Agents. Museum Catalogues, Guides, «o., w» sold at the Museum. QUARTER-INCH Sheet. INDEX MAP OF TH On the scale of l-25th inch Price— Coloured, MAP OF ENGLAND AND Solid. Drift. 8. d. e. d. E BRITISH ISLES. to the mile (1 to 1584000). 2s., Uncoloured, 1«. WALES (i-iQch to the mile. Sheet TITLE SHEET 2 — 1 with 2. (ALNWICK, BEHWICK, &o.) 3 6 — 3. (CARLISLE an I. OF MAN) ... 2 6 — 4. (NEWCASTLE, STOOKTON, &o.) ... 2 6 — 4 with 6. (LANCASTER and ISLE OF MAN) 2 6 — (MANOHESTEB, LEEDS, &c.) ... 2 6 — (FLAMBOBO' HEAD and GHIUSBY) 2 2 with 10. (HOLYHEAD, SHREWS- BURY, &o.) 3 6 — {STAFFORD, DEBBY, LINCOLN, &c) 3 6 — (LOTTTH and YARMOUTH) 3 6 2 6 7. 11. 13. 1 to 253440). Solid. Drift. f. d. ». d. Solid. Drift. Memoir. i. d. ». d. «. d. S 3 1 6 — 5 3 1 6 1 6 1 6 9 1 6 1 6 10 6 1 6 1 6 9 9 1 6 with 42 9 1 6 1 6 9 1 6 1 1 6 l 4 6 8 3 3 6 9 9 1 6 1 6 4 6 1 6 9 1 6 1 « 1 3 9 1 6 1 6 5 3 1 6 — 1 6 — _ 1 6 2 6 — 1 6 3 — 1 6 3 1 1 1 6 1 6 — 16 3 ONE-INCH MAP, NEW SERIES (1 inch to the mile, These are published in either 'a " Solid " or a *' accompanied by Explanatory Memoirs. New Series the Old Series Map 91 to 110. Some of these are now rest are still issued as sheets of the Old Series Map. Prioe of Map. 43. STOOKTON 44. GUISBROUGH _ 15 and 44. SOALBY and WHITBY 43. NORTHALLERTON 43. EGTON 42. BIPON and THIBSK ... 68. PICKERING 44. SCARBOBOUGH 15. FLAMBOBOUGH 42. HARROGATE 43. YORK 64. DRIFFIELD 65. BRIDLINGTON " 71. SELBY 72. BEVEBLEY 73. HOBNSEA 110. MACCLESFIELD, CON- GLETON 112. CHESTERFIELD 113. OLLEBTON 133. STOKE-UPON-TBENT ... 135. DEBBY ' and WIBKS- WORTH 126. NEWARK and NOT- TINGHAM 141. LOUGHBOROUGH and BURTON 142. MELTON MOWBBAY ... 155. ATHERSTONE and CHABNWOOD 1(6. LEICESTER 167. HUNTINGDON 303. BEDFORD 338. HAVEBFOBDWEST 329. OABMABTHEN 230. AMMANFOBD -231. MEBTHYB TYDFIL 133. ABEBGAVENNY 346. WEST GOWEB r347. SWANSEA ... 448. PONTYPRIDD 149. NEWPORT (Mon.) 364. HENLEY-ON-THAMES ... 261-3. BRIDGEND 163. CARDIFF 167. HUNGER'FOHD and NEW- BUBY> -368. BEADING 169. WINDSOR .182. DEVIZES 183. ANDOVEB -284. BASINGSTOKE 296. TAUNTON and BRIDG- WATER ■208. SALISBURY -J!39. WINCHESTER with part of 17. (FISHGUARD, MILFORD) •■■ 8 6 — (ABEBYSTWYTH, HEBEFOBD) ... 2 6 — (BIRMINGHAM, OXFORD) ... 2 6 — (CAMBBIDGE, IPSWICH) ... ...2636 (BRISTOL, CABDIFF, &o.)... 2 6 — (BATH, GUILDFOBD, SOUTH- AMPTON) ... 3 6 — with 24. (LONDON, DOVER, and BBIGHTON) ... ... 2 6 3 6 21 with 25. (FALMOUTH with ISLES OF SCILLY) 3 6 — 22. (PLYMOUTH and LYME REGIS)... 2 6 — 23. (BOURNEMOUTH to SELSEY BILL) 2 — INDEX to COLOURS and SYMBOLS ... 2 6 — or 1 to 63360) WITH ACCOMPANYING MEMOIRS. Drift " Edition, or in both. The majority ol them are Sheets 1 to 73 correspond to the Quarter Sheets of colour-printed, and are given in the table below; the — 16 3 3 1 6 3 — 1 6 2 3 1 s 1 6 2 8 3 1 6 3 — 6 — - — 9 9 _ — 3 6 1 6 1 6 2 1 6 1 6 2 6 1 6 1 6 1 6 1 6 1 6 3 1 6 1 6 8 1 8 1 6 3 6 1 6 1 6 1 6 1 6 1 8 1 6 — 1 6 3 1 6 1 6 1 6 1 6 1 6 3 1 6 3 6 6 9 1 6 1 6 — 3 6 — 1 6 1 — 1 8 1 6 — 1 6 3 _ 1 6 2 — 1 6 1 3 — 1 6 1 6 300. ALRESFORD 311. WELLINGTON and CHARD 314. RINGWOOD 316. SOUTHAMPTON 316. HAVANT 317. "CHICHESTER 325. EXETEB .., 326 and 340. SIDMOUTH and LYME BEGIS 328. DORCHESTER 329. BOURNEMOUTH 330. NEW FOREST (pts.), I. of WIGHT (pts) ... 331. PORTSMOUTH and I. Off WIGHT (pt.) 332. BOGNOB 333. WORTHING and BOT- TINGDEAN 334. NEWHAVEN and EAST- BOURNE 335. TREVOSE HEAD 336. OAMELFORD 337. TAVISTOCK and LAUNOESTON 338. DARTMOOR 339. NEWTON ABBOT 341. WEST FLEET 342. PO RTLAN D and WEY- MOUTH 346. SWANAGE 346. NEWQUAY 347. B O D M I N and ST. AUST ELL ; 348. PLYMOUTH and LI8- KEABD 349. IVYBRIDGE 350. TORQUAY 351 and 358. LAND'S DI8TBI0T 362. FALMOUTH TRURO 353. MEVAGISSEY 355. KINGSBREDGE ... 356. START POINT ... 357 and 360. ISLES SCILLY 869. LIZARD LONDON (4 Sheets), eaoh .'." ISLE OF MAN (Sheets 36, 45, 46, 56 and 67) ISLE OF WIGHT (Special Sheet) NOTTINGHAM (Bpeoial Sheet) ... OXFORD (Special Sheet) END and OF Price of Map. Solid. Drift. Memoir. «. d. t. d. •. d. — 1 6 3 • — 1 6 1 6 1 6 1 6 1 6 1 6 1 8 1 1 6 1. 3 1 3 • 6 8 1 6 1 6 1 6 1 6 1 4 7 « 1 6 — 5 S 2 1 6 1 6 6 — 1 6 — _ _ 1 6 6 1 8 """" 1 8 1 6 1 6 1 t\ 1 3 S 8 — 1 f io e 3 - 1 6 4 _ _ 1 6 1 6 1 6 1 6 S 3 - 2 6 2 6 - 1 6 1 6 1 6) 1 «i 7 6 1 6 1 6 — 1 6 1 6 1 6 1 5 1 11 1 6 11 — 3 6 8 — 1 8 1 6 S 3 3 MEMOIRS OF THE GEOLOGICAL SURVEY- ENGLAND AND WALES. EXPLANATION OP QUARTER SHEETS 95 N.W. AND 104 S.E. (NEW SERIES 35 AND 44.) THE GEOLOGY OF THE COUNTRY BETWEEN WHITBY AM) SCARBOROUGH. BY C. FOX-STRANGWAYS, F.G.S., and G. BARROW, F.G.S. SECOND EDITION. WITH A CHAPTEK ON THE PAL^EONTOLOGICAL CLASSIFICATION OF THE LOCAL JURASSIC ROCKS BY S. S. BUCKMAN, F.G.S. PUBLISHED BY ORDER OV THE LORDS COMMISSIONERS OF HIS MAJESTY'S TREASURY. LONDON: PRINTED UNDER THE AUTHORITY OP HIS MAJESTY'S STATIONERY OFFICE By JAS. TRUSCOTT and SON, Ltd., Cannon Stkeet, E.C. And to be purchased from B. STANFORD, Ltd., 12, 13 and 14, Long Acre, London, W.C. ; W. and A. K. JOHNSTON, Ltd., 2, St. Andbbw Square, Edinburgh ; HODGES, FIGGIS and Co., Ltd., 104, Gbapton Stebbt, Dublin. From any Agent for the sale of Ordnance Survey Maps : or through any Bookseller, from T. FISHER UNWIN, Limited, 1, Adelphi Tebbace, London, W.C, who is the Wholesale Agent to the Trade outside the County of London. 1915. Price 2s. 6d. V C-ORNJELI U'WIVLMU.-IVY h 1 .!■• n a i-> v 11 PREFACE (to the fibst edition). The north-eastern parts of Yorkshire, with their admirably clear coast-sections of the Jurassic rocks, have been classic ground to the geologist since the first general sketch of their structure was published in 1815 by William Smith. From that date down to the present time they have been the subject of a voluminous literature. Smith himself elaborated his first outlines, and published a more detailed map of Yorkshire (1821). Shortly afterwards came the " Geological Survey of the Yorkshire Coast " by Young and Bird (1822), followed a few years later by Phillips' " Geology of the Yorkshire Coast " (1829). Of the numerous fossil mollusca obtained by various collectors from these shores, figures and descriptions con- tinued to appear in Sowerby's "Mineral Conchology" (1812-1829), and furnished the first basis for palaeontological comparison. The more recent contributions are too numerous to find even mention here. But reference may be made to the important labours of Blake, Davidson, Hudleston, Leckenby, Lycett, Morris, Simpson. Tate, Williamson, Wright, and others. The Maps, Sections, and Memoir, now published by the Geological Survey from original observation, afford some measure of the advance made in geological mapping since Smith's first masterly outlines were published, sixty-seven years ago. From the manner in which the Jurassic rocks of Yorkshire, as exposed on the coast line and in the interior, can be subdivided and traced, they present an admirable area for the study of geological structure and the relations of this structure to the forms of the ground. The quarter-sheet of which the following chapters are an explanation affords ample material for the prosecution of this study. Regarding the interesting estuarine character of the Lower Oolites, already discussed in previously published Memoirs (95 S.W. and S.E. and 96 S.E.), further information is here given, the whole series of strata being well developed in the district, and the marine bands being specially distinct. From an economic point of view much importance attaches to the ironstones of the Middle Lias. These are briefly referred to here, but fuller information regarding them will be given in the Memoir descriptive of the typical Cleveland district where the ironstone is so largely developed (Sheet 104 S.W. and S.E.) ARCH. GEIKIE, 9th October, 1882. Director General. Ill PREFACE (to the second edition). In the first edition of this Memoir the area represented in the Quarter Sheet 95 NW. of the Old-Series One-Inch Map was described. The New-Series colour-printed Sheet 44 covers the same ground, but on it is inset the part of the coast-region which is represented in Sheet 35. The second edition consequently includes an account of an area for which reference had formerly to be made to the North Cleveland Memoir. During the 33 years which have elapsed since the publication of the first edition much has been written on the geology of this classic coast. The publication in 1902 of the General Memoir on the Jurassic Rocks of Britain, Vol. I (Yorkshire), provided the late Mr. Strangways with an opportunity of giving the results of the latest work by. .himself and others. These have been incorporated in the present volume. Among other important publications mention may be made of Prof. Kendall's paper on a System of Glacier-Lakes in the Cleveland District, published by the Geological Society of London in 1902. In the preparation of the second edition, in which Mr. Barrow has taken a large share, we have .to acknowledge the assistance rendered by Prof. A. C. Seward, Prof. A. G. Nathorst and Mr. H. Hamshaw Thomas, through which it has been found possible to present the palseobotanical work contained in Chapter VI. The Ammonites of Yorkshire have long engaged attention and are being treated in great detail by Mr. Buckman. The species made by early authors have been critically examined by him and found rarely to be sufficiently restricted for modern palaeontological purposes. He has therefore worked with a more detailed and more exact nomenclature, and at the same time has fixed with a greater precision than was possible heretofore the position which each form occupies in the stratigraphical column. The classification of the strata which has emerged from his labours differs in some details from that which is founded on lithological characters, as indeed could only be expected. Each has its value, and in Chapter V an account has been furnished by Mr. Buckman which enables a comparison to be made between the results of the two methods of classification. Mr. Lamplugh has contributed the introductory chapter and the general account of the Glacial deposits, in addition to editing the whole volume. A. STRAHAN, Geological Survey Office, Director. • 28, Jermyn Street, London, S.W., 21st May, 1915. IV CONTENTS, Page. Preface to the first edition ... ... ... ... ... ... ii Preface to the present edition ... ... ... ... ... ... iii Chapter I. — Physical Features and Geological Structure ,. ; 1-6 Introduction, 1 ; Geological Structure, 3 ; Jurassic Rocks, 4; Jurassic Fossils, 5 ; Table of Formations, 6. Chapter II.— Lias 7-22 Lower Lias, 7 ; Middle Lias, 10 ; Upper Lias. 15 ; Vertebrate Fossils of Upper Lias, 19 ; Blea Wyke Series, 20. Chapter III. — Lower Oolite 23-47 The Dogger, 24 ; Lower Estuarine Series and Eller Beck Bed, 29 ; Millepore Bed, 34 ; Middle Estuarine Series, 36 ; Grey- Limestone Series, 37 ; Upper Estuarine Series, 44 ; Cornbrash, 46. Chapter IV. — Middle Oolite 48-58 Kellaways Rock, 49 ; Oxford Clay, 51 ; Lower Calcareous Grit, 52; Passage Beds or Greystone, 54; Coralline Oolite and Upper Calcareous Grit, 55. Chapter V. — A Pal^ontological Classification of the Jurassic Rocks of the Whitby District, with a Zonal Table of Lias Ammonites. By S. S. Buckman 59-102 Introduction, 59. Lias, 63 : — a. Hettangian, 66 ; 6. Sinemurian, 66 ; c. Char- mouthian, 68 ; d. Domerian, 71 ; e. Whitbian, 74 ; /. Yeovilian, 78. The Peak Fault, 82. Lower Oolites, 83 :— The Dogger, 83 ; Millepore Bed, 84 ; Grey Limestone Series, 84 ; Moor Grit, 85 ; Upper Estuarine Series, 85 ; Cornbrash, 85. Middle Oolites, 86 : — Callovian and Divesian, 86 ; Argo- vian, 87. Appendix : Zonal List of Lias Ammonites, 89. Chapter VI. — Fossil Plants of the Lower Oolite 103-112 General account, 103 ; List of Species, 106 ; Bibliography, 109. Chapter VII. — The Basaltic Dyke 113-114 Chapter VIII. — Structural Conditions and Faults 115-117 Chapter IX. — Superficial Deposits 118-124 Glacial : General account, 118 ; Local details, 120 ; Topo- graphical Features due to the Glaciation, 121. Post-Glacial Deposits : Alluvium, 123 ; Peat, 124. Chapter X. — Economic Geology 125-133 Alum, 125; Coal, 126; Ironstone, 1 26 ; Jet, 126; Mineral Oil, 127 ; Building Stone, 128 ; Lime and Cement. 129 ; Bricks, Tiles, etc., 129 ; Road-metal, 129 ; Soils, etc., 130 ; Water Supply, 130. Appendix. — Short List of Works on the Geology of the District 134-136 Index 137-144 THE GEOLOGY OF THE COUNTRY BETWEEN WHITBY AND SCARBOROUGH. CHAPTER I. PHYSICAL FEATURES AND GEOLOGICAL STRUCTURE. Intboduction. The previous edition of this memoir, describing the hand-coloured map, dealt only with the area included within the Old-Series Quarter Sheet 95 NW. (New-Series, Sheet 44) of the One-Inch map. When this map was prepared for a coloured-printed edition it was decided to include, as an inset in the blank sea-space, the small triangular area around Whitby which was represented on the Sheet to the north (104 SE. of the Old-Series map ; 35, New-Series). The original description of this area was embodied with that of the next Sheet westward (104 SW. Old-Series ; 34, New-Series) in a memoir entitled ' The Geology of North Cleveland' (published, 1888); the ^description has been revised and incorporated in the present memoir, to correspond with the new map. The limits of the tract are shown in the sketch-map on the next page. Geological maps on the scale of six inches to a mile have also been published, where the Six-inch Sheets include or approach the coast-line, these Sheets being Nos. 20, 32, 33, 46, 47, 62, 77 and 78. The geology of the district is further illustrated by the published ' Horizontal Sections,' Nos. 130, 134, 135 and 137 ; and by ' Vertical Sections,' Sheet 67- {See List on inside page of Back Cover.) The land-area to be dealt with measures rather less than 100 sq. miles, and is composed principally of the high uncultivated moorlands between the valley of the Esk and the Vale of Pickering. These moorlands rise to over 900 ft. above O.D. in the western part of the map, culminating at 957 ft. 1 on Lilla Howe, Fylingdales Moor. To the north of the moorlands the valley of the Esk and its tributaries forms a broad irregular depression of fertile country extending to the coast west of Whitby, and linking on the south-east with an amphi- theatre of similar land which is truncated by the sea in Robin Hood's Bay. Farther to the south the moorland valley of Harwood-dale extends into a fertile lowland around Cloughton and Seal by and is continued coastwise to the northern suburbs of Scarborough. 1 This altitude is taken from the contoured Ordnance 1-inch map. In the former edition of the memoir the height was stated to be 978 ft. (3798.) Wt. 49980-2. 500. 10/15. J.T.&S. 14. a PHYSICAL FEATCBES. Similar conditions also prevail on a smaller scale in the separate valley of Staintondale, north of Cloughton. Northward and eastward the land breaks off everywhere in bold cliffs, trenched here and there by the ravines of streams discharging to the sea. These cliffs are for the most part rocky precipices, which, at Peak, their highest point, rise to over 600 feet above the sea ; but where valleys reach the coast the cliffs are partly, and in a few places wholly, composed of softer Glacial deposits of clay and sand, and present a less formidable barrier seaward. The excellent sections, together with the picturesque beauty of the cliff-scenery, have rendered the coast a favourite resort of geologists from the early days of the science when the region was made famous by the classical researches of William Smith, Young and Bird, and Phillips. Sketch-map oe area in Sheets 35 and 44. The stippling indicates the tracts covered by Glacial deposits. Sh.3S \fiverdale Wyka Sandsend Sh.4-4- Scarborough HTII 10 MILES SHAPE AND STEtTCTTTEE. O The moorlands, especially in their southern portion, are sharply trenched by ramifying valleys, in which shelf-like features due to the alternation of hard and soft strata are admirably displayed, enhancing their attractiveness for the physiographer and geologist. Still another point of physiographical interest is the presence on the high moors of a series of curious ravines whose excavation is inexplicable under present conditions, but has been shown by Prof. P. F. Kendall to be due to the flood-waters from the great ice-sheet of Glacial times (see Chap. IX, p. 122). The river Esk, with its outfall at Whitby, drains most of the northern area. The head-waters of the Derwent river gather on the moorland farther southward and flow through deep ravines south and south-eastward till they reach the Vale of Pickering in the country three or four miles south of the present map ; this drainage probably at a former time went eastward to the sea (see p. 123) and an artificial cut still conveys the flood-waters of the river across the low ground in this direction to an outfall near Scalby Ness. Minor streams or ' becks,' with short courses, flow directly to the sea west of Whitby and in Robin Hood's Bay and Hayburn Wyke. The largest town actually within the area is Whitby ; but, as previously mentioned, the outskirts of Scarborough enter the southern margin. Robin Hood's Bay, until recently a Ashing village, is now developing as a holiday resort, and a new watering-place has been established at Ravenscar on the headland of Peak. Scalby, Burniston, Olonghton and Sandsend on or near the coast, and Hackness, Sleights, Aislaby and Sneaton in valleys farther inland, are villages that now profit more or less from the summer visitors, The only population of the moorland district is in the scattered farmsteads of the valleys. Geological Stbuotuee. The ' solid ' rocks of the area belong entirely to the Jurassic system, ranging from the Lower Lias upward to about the top of the Middle Oolite series. On the lower ground to the north and east, however, the Jurassic strata are more or less thickly covered by irregular * superficial ' deposits of Glacial age, mainly Boulder Clay ; while in the larger valleys there are Recent river-deposits of alluvium and gravel ; and on the moorlands, some tracts of peat. The dip of the stratified rocks is for the most part very gently south- ward, so that the newer Jurassic strata are found in a belt only along the southern portion of the area. This dip prevails as far northward as Robin Hood's Bay, where the lowest beds of the district are exposed. But here the strata curve over in a gentle arch or anticline, as illustrated in the section at the foot of the map, and the major part of the Lias sinks again beneath sea-level between this place and Whitby. The prevailing simplicity of the geological structure is broken by a bifurcating fault, striking nearly north and south, which intercepts the coast near Peak and is accompanied by a peculiar change in the development of the lowermost Oolitic beds, as described in the next chapter (p. 20). A bifurcating fault also interrupts the regular a2 4 GEOLOGICAZ STRUCTURE. succession in the headland at the northern side of Scarborough, and another fault brings down the Lower Oolite westward against the Upper Lias at Whitby (see Chap. VIII). In the north-western part of the moorlands the strata are traversed by the great intrusive dyke of basalt of Tertiary age, known as the Cleveland Dyke, which is prolonged into this area from the country to the north-west and con- tinues its course towards east-south-east for over four miles more, bat is then lost. Jurassic Rocks. The mapping of these rocks for practical purposes depends chiefly upon their lithological composition. The main characters of the divisions will here be epitomized prior to their fuller description in subsequent chapters. The Lias consists largely of shale, with subordinate bands of argillaceous limestone and of calcareous sandstone and ironstone, its total thickness being about 900 ft. These sediments are entirely marine ; and most of the beds are fossiliferous, often richly so. The series is separated on the map into three main subdivisions based on differences of composition : — Lower Lias, exposed in Robin Hood's Bay to a thickness of about 460 ft., consisting mainly of sandy or mica- ceous shale with thin calcareous and siliceous hard bands in the lower part ; Middle Lias, under 200 ft. thick, best exposed on the coast north of Robin Hood's Bay, consisting in the lower part of sandy shale with thin stone-bands and in the upper part of ferruginous shales with bands of ironstone ; and Upper Lias, 250 to 300 ft. thick, composed almost wholly of shales with bands of hard nodules, best seen in the cliffs between Hawsker and Whitby, and in those north of Peak and north of Sandsend. The valley of the Bsk around Sleights is carved out of the comparatively soft Liassic strata ; and the great embayment of low country between Robin Hood's Bay and Peak is of similar origin. The Lower Oolites which cover most of the high moorlands and monopolise the coast between Peak and the outskirts of Scarborough are composed mainly of thick sandstones and shales of fresh-water or estuarine origin, with some intercalated belts of marine strata con- sisting in part of calcareous shale and calcareous sandstone, the maximum thickness of the whole series being about 650 feet. The series exhibits much local variation, particularly in the lower portion. It is the presence of thick beds of sandstone at several horizons that brings about the elevated character of the country and the bold coast scenery which characterises the outcrop of the Lower Oolites. The Middle Oolites which form the moorlands and tabular hills, with deep intervening ravines, to the south of the high moors are composed of strata entirely of marine origin. The lowest portion is a massive but rather loamy sandstone known as Kellaways Rock. This is overlain by thick sandy Rhale (Oxford Clay) which is readily removed by sub-aerial erosion where uncovered. The harder beds that form the upper part of the Middle Oolites are known as the Corallian Series ; they consist of alternations of FOSSIL ZONES. 5 calcareous sandstone and limestone, which give rise to the sharp edges of the tabular hills and cap the narrow ridges between the ravines, causing the picturesque outlines of the country near the headwaters of the Derwent. On the coast, the Middle Oolites form the Castle Hill of Scarborough, which falls across the southern edge of the map. The thickness of the Middle Oolites averages over 400 feet. They are the newest ' solid ' rocks (excepting the Whinstone Dyke) that lie within the limits of the map. Jurassic Fossils. Through the greater part of the Jurassic series fossils occur plenti- fully, particularly in the strata of marine origin, which are often crowded with shells or other calcareous remains, together with less abundant relics of fish, reptiles, etc. In the fresh- water or estuarine deposits of the Lower Oolite, fossils are less commonly distributed and consist chiefly of plant-remains, full of interest to the palasobotanist (see Chapter VI). In the clear and continuous exposure of the strata in the sea-cliffs and on the foreshore, the fossils are particularly conspicuous ; so that the neighbourhood of Whitby was celebrated for its ' snakestones ' and ' thunderbolts ' long before the days when, as ' ammonites ' and ' belemnites,' their true nature was realised. In the early days of geological science, from the time of William Smith onward, it was recognised that the various kinds or species of fossils were not scattered indiscriminately through the rocks, but that certain forms were found only in certain beds, with other kinds in the beds above and below, always in a definite succession. It was further found that the succession of fossils, when thoroughly understood, was extremely helpful in tracing the order of the strata containing them ; and the beds were divided into ' zones,' each characterised ! by particular species of fossils or by groups of species. For this purpose the numerous forms of ammonites found in the Lias and in the marine Oolites are especially useful ; and it is by the close study of these forms and of their variation and development during the long period of Jurassic time that the identification and correlation of the sub- divisions have been most effectively carried out. The characteristic fossils of the different zones have been to some extent indicated on the map in the writing engraved on the sea-space opposite some of the chief fossil-localities on the coast ; and fuller information respecting the fossils is given in the course of the stratigraphical descriptions contained in the next three chapters, based upon the original work of the Survey. Since this work was done, further progress in the discrimination of the species and in the definition of the zones has been made by Mr. S. S. Buckman and other workers ; the result of the latest researches is given separately in Chapter V (p. 59), prepared by Mr. Buckman. As therein explained, the newer nomenclature of the fossils and classification of the zones differ in many respects from that used on the map ; but the relation of the new work to the original record is made clear by the Comparative Tables given on pp. 60, 61. GEOLOGICAL STETJCTTTBE. The order of the formations represented on the map is as shown in the following table : — Post-Tertiary Table op Formations. Superficial Formations. C Alluvium. Post-Glacial < River Terraces. (.Peat. r,-, ■■, f Boulder Clay, with Glacial | gand and Grayel Tertiary Intrusive Igneous Rock. Basalt ... Whinstone Dyke. Solid Formations. Jurassic Middle Oolite Lower Oolite Lias 1 Upper Calcareous Grit, •j „, +j ( Upper Limestone. j o -9 "o i Middle Calcareous Grit. 2 j O "" O (, Lower Limestone. q Passage Beds. (^Lower Calcareous Grit. Oxford Clay. Kellaways Bock, f Cornbrash. "Upper Estuarine Series (with Moor Grit at base). Grey Limestone Series (marine). Middle Estuarine Series. Millepore Bed (marine). Lower Estuarine Series (with Eller Beck Bed, marine). The Dogger (marine). 'Blea Wyke Beds (sandy). Upper Lias (with Jet Bock). 1 Middle Lias (with ironstones). (.Lower Lias. CHAPTER II. LIAS. As outlined in the preceding chapter, the area occupied by the outcrop of the Lias in the district is confined to a coastal tract ex- tending almost continuously northward from Peak, and a smaller tract in the valley of the Bsk. The lowermost beds of the formation are not exposed, though they may occur beneath the sea off Robin Hood's Bay. The highest beds are seen only in the cliffs between Blea Wyke and Peak ; if ever deposited in the remainder of the area, they were destroyed before the overlying Oolitic series was laid down. The formation is separated on the map into three principal divisions, viz., Upper Lias, Middle Lias, and Lower Lias. These divisions, as already explained, are based mainly upon differences in the composition of the strata, while a more elaborate classification, with different boundaries, has been made by means of the fossils, as described in Chapter V. Lower Lias. Besides its chief outcrop in Robin Hood's Bay, the Lower Lias emerges also in the valley of the Esk around Sleights, in the north- western corner of Sheet 44. In both areas its boundaries are mainly hidden by Glacial drift, but the strata are fortunately open to examina- tion in excellent sections in the cliffs and on the shore of the Bay. As seen in these sections, the Lower Lias may be roughly subdivided as follows, in descending sequence. Thickness ft. B.b. Soft shales with rows of ironstone ' doggers * 7 , , , M B.a. Soft shales with rows of pyritous nodules j aoout A.b. Shales with hard sandy bands, the upper parts *\ covered with fucoidal markings l -,^r. A.a. Shales with marly calcareous bands, generally f " very shelly J (A.a.) These lowest beds are seen only at low water, forming the series of outer scars in the bay, dipping in a direction at right angles to the coast line. The average dip is about 1°, and as the breadth of the outcrop is about 300 yards the thickness of rock exposed may be as much as 60 feet, consisting of rather soft grey shales with harder sandy and somewhat calcareous bands interspersed. These scars are often so covered with weed that it is impossible to examine them ; but at the end of a hot summer the weed dies and is washed away, so that the scars can be best studied in September and October. As, however, they are only exposed for some distance 8 LIAS. seaward at low spring tides, they are never very easily investigated. On the outer soars Arnioceras semicostatwm (Y. and B.) and other species of this genus of ammonites are abundant, and nearer the cliff there are layers of Hippopodium ponderosum, J. Sow. Tate and Elake, who assigned these beds to the zone of Amm. bueklandi, have recorded many fossils from them, including species of Qryphaea, Lima, Monotis, Pecten, Perna, Gardinia, etc., with some ammonites, belemnites and gasteropods. 1 The latest classification is given by Mr. S. S. Buckman in Chapter V, pp. 61, 68. (A.b.) The next subdivision in the upward sequence has been known as the zone of Amm. oxynotus, but this term is now restricted to only a portion of the beds (see Table, p. 61). It consists of alternating layers of soft shale and rather hard sandy marl, remark- able for the number and variety of the ammonites they contain, and for the curious ftujoidal markings rendered visible on the sandy bands where washed by the sea. A detailed section of the subdivision as exposed in Robin Hood's Bay is reproduced from the former edition of this memoir with some modification and the addition of later particulars respecting the ammonites and some other fossils in Chapter V, p. 67. The highest of these beds forms the scar opposite Bay Town, at which point the strata are dipping due north. Southward they rise into the cliff until near the middle of the bay, where the dip is nearly due west and the highest bed is about 90 feet above sea-level. Then the dip gradually changes to south, and the strata descend until, against the Peak Fault, the highest bed again forms part of the tidal scar, about 100 yards from the cliff. The series is thus brought within reach twice, in separate parts of the cliff. A point of interest is the occurrence, about the middle of the series, of large lenticular discs of ironstone, sometimes as much as 15 feet in diameter, usually unfossiliferous, with cone-in-cone structure developed in the lower part. They generally rest on a mass of broken fragments of Pentacrinus. Many of the smaller nodules or doggers contain the remains of ammonites, particularly in certain bands toward the middle of the section (see p. 67), but fossils other than ammonites are rarely abundant. The average thickness of the subdivision is about 110 feet. (B.a.) This portion of the Lower Lias was formerly classed as the zone of Amm. jamesoni, with sub-zones in the lower and upper part. The latest palaeontological classification is set forth in Chapter V, p. 70, with a detailed section of the beds as exposed in Robin Hood's Bay.* The shales of this subdivision are mostly soft, dark, and argilla- ceous, particularly in the lower part. They are also more micaceous 3 than the rest of the Lower Lias, and contain rows of small ironstone 1 ' The Yorkshire Lias.' 8vo, Lond., 1876. pp. 54-71. * Other renderings of this section were published in the previous edition of the present coemoir, p. 6, and in the general memoir ' The Jurassic Rocks of Britain,' vol. I (1892) pp. 50-2, the details in the latter case being reproduced from Tate and Blake's ' Yorkshire Lias,' p. 48. s The shape and character o£ the flakes of mica, together with that of the grains of quartz and felspar, imply that the material has been derived from an area of crystalline schists. [G.B.] LOWEB, LIAS. 9 nodules or doggers, which in the lower part of the subdivision usually consist of iron pyrites, often in distinct crystals. The abun- dance of pyrites is characteristic of these beds, and in some cases the casts of the ammonites are entirely composed of it. The beds may be examined on the scars from opposite the life- boat house at Bay Town northwards toward North Cheek. They form a broad flat expanse of shale, with fossils occurring at irregular, intervals, singly or in calcareous masses. The chief fossils which occur scattered are the ammonites, while the masses consist mainly of the shells of gryphaea, pecten and belemnites, in small somewhat conical heaps, these forming a feature characteristic of this part of the Lower Lias. Pinna occurs abundantly throughout; Gryphaea cymbium Lam. is found in greatest profusion near the base ; and it is noteworthy that while, in the shales just above the zone of Amm. oxynotus, this fossil is narrow and sulcate, much resembling the true G. arcuata Lam., as it passes upward the form grows gradually more dilate and the sulcus becomes almost invisible. The only other exposures of the subdivision are in the sides of the small streams, such as Mill Beck, that flow into Kobin Hood's Bay, and in the base of the high cliff on the north-western side of the great Peak Fault. ' (B.b.) The beds of this subdivision constitute roughly the zone of Amm. capricornu8 of the older classification, in which, however, it was recognised that there were difficulties with respect to the upper and lower limits of the zone. The modern method of zoning and its relations to the older method are displayed in Table I, p. 61, while the details of the sequence, as seen around Robin Hood's Bay, are shown in the section given on pp. 69, 70. These strata consist of about 140 ft. of grey micaceous shale, light- coloured and sandy in the upper part, darker and more argillaceous in the lower. Perhaps their most characteristic feature is the occur- rence of bands of ironstone doggers, often septarian, at intervals of a few feet. The septarian doggers constantly contain zinc-blende, and in many cases the ammonites within them occur as casts entirely composed of blende. Some of these bands are very persistent, and are traceable as far as the beds of shale in which they occur. Two in particular, a few feet apart, may be noticed about 50 feet below the top of the subdivision ; the upper contains a Lytoceras, and the lower is a thin seam of white-speckled clay-ironstone with a layer of small pectens and belemnites at the base 1 . Others no doubt are similarly persistent but lack peculiarities by which they can be traced. On the shore and in the cliff at Robin Hood's Bay a complete sequence of these beds is exposed, from their upward junction with the Middle Lias at North Cheek to their gradual downward passage to the subdivision below. The upper beds are rather hard, sandy and micaceous, being also very regularly jointed. In consequence of this latter feature, large prismatic blocks, often nearly a ton in weight, fall from the face of the cliff ; and in these blocks specimens of Capricorn ammonites are fairly abundant, accompanied by and sometimes in- cluded in small round ferruginous doggers, in shape not unlike cannon ? These two bands can be seen again at Staithes, and followed thence to Saltburn, 20 miles from Robin Hood's Bay. 10 LIAS. balls. An immense accumulation of such blocks may be seen at the foot of the cliff on the north-west side of the Peak Fault, the place from which they have fallen being inaccessible. As a whole, these beds do not yield many fossils. One or two species of ammonites and a small pecten are, nevertheless, fairly abundant in certain lines of doggers. Besides the section on the shore, there are other exposures of these beds in the ravines in the Kobin Hood's Bay district, where, however, they are generally difficult to examine, as the streams in passing over them have cut deep gorges with occasional pools and small waterfalls, making many of the finest sections inaccessible. The upper part, with Capricorn ammonites in the small round ironstone doggers, is well shown in Tan Beck, above the Peak Alum Works. In Butcher Close Wood there is a gorge in black shale with flat ironstone doggers in bands, giving a clear section of nearly the whole of the subdivision, consisting of the dark bluish lumpy shales with iron-stained edges, and rows of ironstone doggers enclosing the typical ammonite. A nearly similar section may be seen in Mill Beck, the other branch of the stream, a little below the new bridge on the road from Park Gate to Fyling Hall. Other sections of these beds are to be found in Eskdale, in the banks of the Esk between Sleights and Grosmont. The finest is at Blue Scar, so called from an exposure of these bluish-grey shales, nearly 100 ft. in height, with many rows of ironstone doggers. The steepness of the scar limits the search for fossils, though ammonites and small belemnites may occasionally be obtained. On the north bank of the river two small sections are exposed in the railway- cuttings close by the stream ; the first shows bluish shale with several rows of small flat ironstone doggers ; the second, south-west of the former, shows a lighter coloured and more sandy shale, with the basement beds of the Middle Lias above. Middle Lias. The beds classed as Middle Lias on the map form a well-defined lithological division which is subdivided into two parts, separately distinguished on the map. The lower subdivision, 50-60 ft. thick, discriminated as the ' Sandy Series,' consists of sandstones and hard shales, with thick fossiliferous bands constituting a sandy marl ; the upper subdivision, 90-100 ft. thick, known as the ' Ironstone Series,' is made up mainly of shales with thin bands of ironstone. The whole division is characterised by the large quantity of iron contained in the beds, either localised in bands, as in the upper subdivision, or dis- tributed through the rock, as in the lower sandstones which often contain more than 15 per cent, of it. In both subdivisions the iron occurs in the form of carbonate, which imparts a blue colour to the rock when unweathered. Owing to their blue colour when found at considerable depth, the sandstones of the lower subdivision in certain cases have been mistaken for the main seam of ironstone of the upper subdivision ; but on exposure to the atmosphere the sand- stones often change to soft rusty micaceous flags. Palseontologically the Middle Lias was considered by the earlier workers to comprise two zones, that of Amm. margaritatus below, and that of Amm. spmatus above, these being roughly, but not exactly, MIDDLE LIAS. 11 equivalent to the ' Sandy Series ' and the ' Ironstone Series ' respec- tively. At the same time it was recognised and. discussed in the former edition of this memoir that, in respect to the Middle Lias particularly, the lithological subdivisions were not coincident with the palsBontological subdivisions based on the ammonite-fauna, and that the lower boundary of the Middle Lias was in fact drawn through the middle of the zone of Amm. capricornus. This boundary agreed, however, with that adopted by the Survey for the rest of England, and was practically the only available line for the base of the Middle Lias that could be accurately traced in the field. It was shown to be marked, moreover, both by a well-defined lithological change and by a palseontological difference, the beds above tbis line containing an abundance of shells, while in the beds immediately below there was a striking paucity of fossils. This scheme of division is here adopted, but it. differs from that which is suggested by the later investigation of the ammonite zones, as described in Chapter V. Scmdy Series — The term ' Sandy Series ' has been applied to the lower subdivision of the Middle Lias in preference to Phillips' older hut ill-defined term ' Marlstone ' which has been used too compre- hensively. 1 The beds of the Sandy Series are remarkably profuse in fossils, most belonging, however, to only a few species. Of these, Protoeardia truncata (J. de C. Sow.) is the chief; but in the lower part Gryphaea cymbium Lam. predominates, and is accompanied by Pteria inaequivalvis (J. Sow.), calcareous bands near the base often consisting entirely of these two species. In one particular bed Dentaliym gigantewm Phill. occurs in considerable numbers, while belemnites and pectens are tolerably abundant throughout. The flaggy structure of the weathered rock is partly occasioned by the layers of shells which, mostly in the form of casts, cover the bedding planes. The fallen blocks on the beach may be split along these layers of fossils, yielding excellent hand-specimens of the rock, covered with pectens, gryphites, etc., stained a rich red from the contained iron. The paved footway down the hill to Bay Town is chiefly made of fossiliferous slabs of this kind, carted from the beach where they have been hardened by sea-water. The best section of the Sandy Series is on the coast at Castle Chamber, north of Robin Hood's Bay, where the beds have a thickness of about 54 feet. Full details of this section are given in Chap. V, pp. 69, 74. There are several other exposures of these beds in the Robin Hood's Bay district. On the west side of the Peak Fault the cliff is capped by the sandstones and sandy shale of the series. The pathway down to the great slip under the cliff at Peak is almost on the line of fault, and to the left the sandstones are seen, containing Amaltheut, Hippo- podium ponderosum (J. Sow.), Protoeardia truncata (J. de C. Sow.), and Gryphaea cymbium Lam., in abundance, with Dentalium, &c. From this point the sandy beds make a well-marked terrace round the south-east side of the great amphitheatre of the Bay, and sink under the Boulder Clay beneath the Brow Alum Quarry. t 1 This point is discussed fully in the general memoir, ' The Jurassic Bocks of Britain,' vol. i. ' Yorkshire,' p. 86. 12 LIAS. It is impossible not to regret the presence of this covering; as nothing is more striking v than the extreme symmetry of the south- east end of the Bay, where the beds crop out to the surface in a succession of curving terraces ; while the north end, from its thick covering of Boulder Clay, seems almost shapeless. In the exposed area several small sections may be seen, principally in the narrow but deep ditches that drain the fields ; only in Tan Beck, however, is there a section of the whole of the sandy beds.. The sandstones are cut through in the road at Susanna Hill ; but westward of this we have no sections till we reach Butcher Close "Wood, which is situated on the sides of the south branch of Mill Beck. Here the base of the Sandy Series is exposed, the section showing several feet of hard sandy shale, with a 3-ft. band of laminated sandstone full of casts of Pteria inaequivalvis, Gryphaea cymbium, and Capricorn ammonites. Above this section the stream flows in Boulder Clay. In Mill Beck, about 100 yards west of the New Bridge, hard sandy shales crop out, and from their lithological character we suppose them to be part of this series. There are no more exposures in the district until we again reach the cliff, about 300 yards north of Bay Town ; and from this point the beds fall gradually, till they finally reach the sea-level at Castle Chamber. In Eskdale the first exposures are near Sleights, where the whole series may be seen and examined on the sides of the river. It is not possible to give an accurate detailed section, owing to the bank being often entirely covered by ivy and otber creeping plants, which renders doubtful the tracing of the thin bands. Near Woodlands a small stream cuts through the upper part of the series, and exposes,* at the base of a small fall on the side of the Esk, hard sandy shales, with Pteria, Gryphaea, and occasionally, Capricorn ammonites ; showing that this is near the base of the series. On the opposite side of the river, a little farther up, immediately under the railway, the lowest band of sandstone, with the characteristic ' oyster beds ' consisting of Gryphaea cymbium and Pteria inaequivalvis, may be seen rising from the river, dipping 3° slightly E. of N. The base of the series is seen again half a mile to the SW. in the beck below Eskdale Gate ; but this section is very small, and entirely surrounded by Boulder Clay. A little farther west the hard sandstone beds cap the great scar (Blue Scar) on the south side of the Esk. A complete section is here shown, but is inaccessible. Several sections are exposed beyond the scar, especially in the stream flowing down from the old alum works, where the series may be measured, and gives a total thickness of about 60 ft. As only the edges of the rock-bands are seen, and give no opportunity for collecting the fossils, detailed measurements would be of little value. Upon comparing the various sections of this division of the Middle Lias, it becomes evident that the generalised section is as follows : — (a) Upper part, consisting of two hard thin bands with about four feet of shale beneath each. (b) Main mass of sandstone, with many bands of shells. (c) Thick bed of hard sandy shale, with thin beds of sandstone. This succession is invariable in the district, and there can be no doubt as to the continuity of the two thin hard bands in the division (a). This is an important point, as the upper band becomes MIDDLE LIAS. 13 one of the chief datum-lines for correlating the different seams of ironstone in Cleveland. Ironstone Series. — This appropriate term for the upper sub- division of the Middle Lias in Yorkshire was applied first by Prof. Phillips. In the district under description the series is about 90- 100 ft. in thickness, and consists of shales with thin bands of iron- stone, the shales being soft and argillaceous in the upper and middle portions, and harder and sandy in the lower ; the whole series is pro- lific in fossils. The ironstone bands diminish south-eastward and do not possess the economic importance that they attain in the Cleveland district, but they have been worked to som6 extent in the valley of the Esk in the north-western part of the area, as described below. The best exposure of the series is on the coast from Hawsker Bottoms southward, where a complete section may be studied in the cliffs and on the shore. The stratigraphical details of this section, with mention of the principal fossils, are given in Chapter V, pp. 72-73 ; the thickness of the series at this locality is close upon 100 ft. The only other exposure of this series on the coast is at the Peak Steel, where the base of the subdivision forms a hard triangular patch of rock between the two branches of the Peak Fault, while its top beds are seen on the other side of the eastern branch of this fault. Inland there are several small exposures of the series around the south-east end of Robin Hood's Bay, chiefly under the Peak Alum Works, and along the railway-cutting under the Brow. In the latter, flattened nodules with Amaltheus may be seen at the base of the cutting, while the doggers in the upper part contain the large Pecten in abundance. From the nearness of this section to the jet-workings it is probable that the beds at the top of the cutting, consisting of soft marly shales of a somewhat mottled appearance, containing weathered doggers, represent the Spinatus Beds. In the narrow gorge of Howedale Beck there is a continuous section of the Ironstone Series to a depth of about 80 feet. In this locality the ironstone seams of the northern area have died out, and are repre- ' sented only by bands of nodules at intervals. The shales, too, are more argillaceous and decidedly less sandy than in the other sections. The top of the series is here well defined by a band of nodules with the large Pecten and Pholadomya ambigua. At some depth below, the nodules occasionally contain a small Amaltheus (Amm. clevelandicus of Simpson), but the lowest beds seen do not reach nearly to the base of the series, which apparently may here be about 120 feet thick. From this point northward till the coast-section at Hawsker is reached, the outcrop is entirely concealed by Boulder Clay, with the single exception of a small exposure in the south bank of Bamsdale Beck, showing about six feet of soft shale, with a band of ironstone doggers, probably belonging to the middle of the series. In the part of the Eskdale district that falls within the map there is no complete exposure of the Ironstone Series, so that the following section has been compiled from three different places, one just beyond the western edge of the map. In this area the ironstone bands, two in particular, are much thicker than in the Robin Hood's Bay district, and have been at one time mined for ironstone. 14 LIAS. In. 3 > Pecten Seam 10j Ft. In ' 1 6 ) 5 1 3 10 5 6 4 6 1 6 3 7 27 2 5 6 25 93 3 Section in the Bskdale District. No. 1. Ironstone band of irregular thickness, resting on the Indurated Shale Band 2. Soft ferruginous shale with scattered ironstone doggers and many small fossils, Arnm. sp. Pholodomya, large Pecten, &c. 3. Continuous band of ironstone 4. Shale, dark and ferruginous 5. Ironstone band 6. Shale 7. Dogger band 8. Shale 9. Ironstone band 10. Hard dark shale Ft. f Ironstone ... 11.3 Shale 1 (.Ironstone ... 1 12. Shale 13. Ironstone, Avicula Seam . . . 14. Shale, somewhat sandy 15. Band of hard sandy shale ... 16. Hard shale, somewhat sandy In comparing this section with that at Hawsker (pp. 72-4) there are at least three, and probably four, bases for the correlation. Of these the first is the ' Indurated Shale Band,' ; the second is the ' Pecten Seam ' ; the third is the base of the series, which is in both cases a bluish-coloured marly sandstone ; and in addition, the ' hard sandy band ' associated with the ' sandy ironstone,' No. 25, at Hawsker is almost certainly the same bed as No. 15 of the Bskdale section. From this correlation it is evident that the ironstone diminishes in a south and east direction from Eskdale ; and that the argillaceous shales increase in thickness, while the sandy shales appear to diminish slightly. There are several exposures of the Ironstone Series in lburndale ; the most southerly being in the bed of Little Beck, at Straw Head, where the upper part and its relation to the Upper Lias may be well seen. The bank on the west side of the stream consists of soft Grey Shale (Upper Lias), with decomposed earthy nodules, while near the base there is a small row of ironstone doggers with Pholadomya ambigua (J. Sow.). Two feet below this is the representative of the 'Indurated Shale Band,' so well developed at Hawsker, but which here consists merely of sandy micaceous laminse, and is about 3 inches thick. Farther down the stream, at Throstle Nest and again a few hundred yards farther north, the ' Pecten Seam ' crops out, showing the following section : — Ft. In. Ironstone 101 Ft. In. Shale 4 > Pecten Seam 2 4 Ironstone ... ... 1 2 J Below this is a bank of shale with several thin ironstone-dogger bands, the whole about 20 feet in thickness. The section here is not cut to a sufficient depth to show the ' Avicula Seam,' but the rock next exposed farther down the stream TTPPER LIAS. 15 consists of the rather hard sandy shales below it ; while the seam itself may be seen at the first sharp bend in the stream below Iburndale village, and again, dipping sharply north-east, at the railway bridge. Here the section is : — Ft. Shales, ferruginous and lumpy ... ... ... ... 8 Hard ironstone 10 ") » yj CULA Seam 2 Softer stone, shelly in upper parts 1 2) A small stream that flows down the east side of Iburndale from Ugglebarnby exposes part of the Ironstone Series, probably just above the ' Pecten Seam ' ; a trial-hole has been driven in, exposing now only the top of a seam of ironstone, which has not been further worked. On the north side of the Esk, opposite Sleights Bridge, a shaft was sunk about 30 feet to a seam of ironstone, probably the ' Pecten Seam,' which was worked for several years, producing about 11,000 tons, after which the mine was abandoned. The seam was 3 feet thick, with a shale-parting of 1 foot in the middle. In the north bank of the river, a little farther west, both the ' Pecten ' and the ' Avicula ' seams crop out ; butthe ground is so much obscured by vegetation and clay that it is impossible to obtain a detailed section. From this point the position of the Ironstone Series in the middle of the Esk valley can only be conjectured owing to the deep covering of Boulder Clay and Gravel. On the south bank, however, at the edge of the thick mass of drift, there are several exposures, the seams being also proved by mining at Eskdale Gate. The section of the ' Pecten ' and ' Avicula ' seams here revealed is that shown in the combined Eskdale section already given. A few small exposures occur in the hollow between Oaley House and the old Alum Works, and both seams have been tried immediately under the new Alum Works. But in all these cases the seams have proved too thin and too poor in quality to be long worked at a profit. Upper Lias. The main mass of the Upper Lias is composed almost entirely of more or less argillaceous shales, but the uppermost beds, as developed only in a small area east of the Peak Fault, exhibit a sandy condition. Excluding these sandy beds the thickness of the formation is generally between 200 and 250 feet in the area under description. By differences of lithological composition and fossil contents, the series has been divided into four parts, which again, as will be shown subsequently (Chapter V), may be subdivided into many minor zones characterised by particular species of ammonites. The four divisions adopted during the course of the survey are stated below, in descending order; of these, No. 2. the 'Jet Rock,' is picked out by a separate tint on the map, as well as by a distinctive symbol ; Nos. 1 and 3 are marked by a difference of symbol only ; and the outcrop of No. 4 is too small to be indicated separately. 4. Blea Wyke Series : ' Zone of Amm. jurensis ' (in part), of old zonal classification. 3. Alum Shale Series : ' Zone of Amm. communis' of old classification. 2. Jet Bock Series : ' Zone of Amim. serpentimus " of old classification. 1. Grey Shales Series : ' Zone of Atom, annulatus ' of old classification. 16 LIAS. The distinctive characters and local occurrence of these divisions is discussed seriatim below in ascending sequence. The most extensive clear exposure of the Upper Lias is that of the cliffs and shore between Hawsker and Whitby, where, at different points, a continuous sequence from the base of the Grey Shale to the top of the Alum Shale may be followed ; the details of the strata are included in the full sections [4] p. 75 and [5] p. 79, in Chapter V. The best exposure of the lowest part is on the coast at Hawsker Bottoms, while the uppermost part, as already noted, is seen in the cliff-sections near Peak. In the extreme north of the area described, north of Sandsend, there are again fine cliff-sections of Upper Lias, particularly of the Jet Kock. 1. Grey Shale Series. — These lowest beds of the Upper Lias con- sist of compact grey shales, about 30 feet thick, which easily crumble when exposed to the weather, and are generally worn into hollows ; so that, except on the coast, exposures are rare and more or less obscured by the debris of higher strata. The shales contain numerous nodular bands of earthy impure limestone, often enclosing the charac- teristic ' dactyloid ' ammonite (see p. 76), particularly in two bands occurring close together near the middle of the series. A charac- teristic form of belemnite (' Bel. cylindricus ' of the older records) also occurs fairly plentifully ; otherwise, in comparison with the strata above and below, the Grey Shale is exceptionally poor in fossils, though the lists published by Tate and Blake 1 and others show that a wide range of species is represented. Tate and Blake, on account of the general facies of the fossils, considered that these beds should be classed as Middle Lias, but their suggestion has not been adopted by other observers and is not in agreement with the accepted classification in other parts of Britain. Besides the good exposure on the coast at Hawsker already men- tioned, the Grey Shale crops out on the shore at Peak immediately south-east of the fault, bat it is here always more or less under water and also obscured by loose blocks of sandstone. In the interior, it can be fairly well seen, though rather inaccessibly, in Howedale Gorge ; while there are other exposures in the stream near Littlebeck ; at the bottom of Battlebanks ; and in the little stream or ditch by the road- side at Sleights Bridge. , 2. Jet Rock Series. — The shales, about 90 feet 'thick, comprising this division in its broader sense, although they pass somewhat gradually into the Alum Shale above, present, on the whole, a marked contrast both to them and to the beds below ; the change from the grey crumbling shales to these dark, dense, and finely laminated beds being very striking. The beds are very fossiliferous, being particularly characterised by the abundance of ammonites of the Harpoceras group (see pp. 76, 77), formerly denominated ' Amm. serpentinus,' together with peculiar forms of belemnites (' Bel. tubularis,' &c), a small oyster-like shell ,(' Inoceramus dubius '), and other mollusca, and remains of fish and saurians (see pp. 19-20). The true ' Jet Rock,' from 25 to 30 feet thick, forming the lowest part of the division, consists of hard compact bituminous shale with • ' The Yorkshire Lias, ' p. 172. UPPER LIAS. 17 many rows of nodules in the upper part. The nodules have generally a pyritous skin or coat, often enveloping fossils ; while the interior of the nodule is a hard blue cement-stone with a powerful odour of mineral oil, and occasionally with liquid bitumen in the hollow chambers of ammonites when these fossils occur inside the nodule. The jet, which is believed to have been formed from water-logged coniferous wood but rarely retains any trace of its original structure, (see p. 127), occurs in isolated lumps or lenticles in the hard shale, particularly in the upper part of the bed. This substance, when carved and polished, has been long held in high esteem for ornamental purposes, and Whitby was at one time the centre of a considerable jet-working industry which attained its acme in the middle part of the last century, but is now n arly extinct. 1 In the search for jet, the ' Jet Rock ' has been mined extensively all along its outcrop ; the miners have usually driven a short level until the hard un- weathered rock was reached and have then carried cross-cuts on both sides at right angles to the level. The un weathered shale con- tains an appreciable amount of volatile matter, and may eventually prove to be of some value on this account (see p. 127) ; it is, however, markedly pyritous. The top of the true ' Jet Rock ' is marked by a continuous band of large hard nodules or doggers of calcareous and ferruginous shale, sometimes as much as 15 feet in diameter, which is well exposed on both sides of Saltwick, east of Whitby, at low tide. This band forms a reef that causes a line of white breakers often traceable across Saltwick and thence stretching at low tides westward in a curve till due north of the Abbey at Whitby. The beds above the ' Jet Rock ' proper comprise a mass of hard blue-black shale over 60 feet thick, traversed by indurated bands and rows of nodules, characterised in some bands by distinctive ammonites and belemnites, but allied as a whole to the ' Jet Rock ' fauna, and included with it, under the old nomenclature, in the ' Zone of Amm. serpentmus.' These beds are well exposed and accessible on the coast at Saltwick, where the details incorporated in the section in Chap. V, p. 75, have been measured. At the southern end of its outcrop the Jet Rock Series is visible, though partly covered by debris, at the foot of Peak cliff, on the eastern side of the fault. On the opposite side of the fault it is thrown up into the ground immediately below the Peak Alum Works, where it has been extensively mined along the face of the hill. At Stoupe Brow it is covered by . a thin coat of Boulder Clay, but emerges farther west, and has been much wrought in Howedale. Beyond this point its outcrop is completely hidden till it reaches the North Cheek of Robin Hood's Bay ; after whfch it appears in the face of the cliff, forming the cap-rock at Nigh and Far Jetticks. Its position in the cliff-face is marked by a terrace where the Jet shales have been dug away ; and it reaches the shore, in consequence of the northerly dip, at Hawsker Bottoms. Here the bed can be very conveniently studied and measured. The exposure between this point and Whitby has been dealt with already. 'For fuller account, see C. Fox-Strangways, ' The Jurassic Rocks of Britain : York- shire,' Mem. Geol. Surv., 1892, vol. i, pp. 455-9 ; also condensed in present memoir, Chap. X, pp. 126-7, 18 LIAS. To the west of Whitby the Jet Rock occupies the foreshore from Saiidsend Ness to Overdale, and, keeping in the cliff for a few yards, again forms the scar as far as Loop Wyke. The jet has been largely mined along the foot of the cliff below Goldsborough, the caverns formed by these old workings having a weird appearance. Many ammonites and fish remains may be obtained from the beds in this district. Owing to the quantity of bitumen and pyrites in this rock, spontaneous combustion is often set up, the effects of which are well seen near Old Nab. , Inland the Jet Eock has been mined below the Alum Works in Eskdale, and also near Throstle Nest and Litt]ebeck,-in Iburndale. 3. Alum Shale Series. — These beds, with a thickness of about 100 feet, consist of grey crumbling shale containing much dissemi- nated pyrites which causes a yellow incrustation on the weathered fragments. The shale has a crisp texture which is very perceptible when one walks over it and is at once indicative of the series. The Alum Shale is characterised palffiontologically by the great abundance of ammonites, particularly of forms belonging to the genus Dactylioceras, among which is the species commune that gave the term ' Zone of Amm. communis' to these beds (see p. 61). Belem- nites of several species are likewise abundant ; and among other fossils, the small bivalve shell, Nuculana ovum (J. de C. Sow.) is always conspicuous by its numbers. The beds are also remarkable for the quantity of the remains of fishes and reptiles that they have yielded (see p. 20), some of the latter being of huge size. The upper part of the shale contains lines ol nodules which were formerly used in the manufacture of cement, particularly in the neigh- bourhood of Mulgrave (Sandsend), hence called ' Mulgrave Cement.' The digging and burning of the shale for the production of alum was at one time an industry of great importance but is now extinct (see Chap. X, p. 125). The excavations for the old Alum Works, some of huge extent, are numerous at most parts of the outcrop. The lower beds, which do not yield sulphate of alumina and consequently were not used in the alum industry, are darker and more bituminous. . On the south, the Alum Shales are first seen at a few places between Blea Wyke and the Peak Fault, but from the large amount of landslips and tumbled cliff the sections are of no great extent. On the west side of the Peak Fault there are good exposures, especially in the great abandoned Alum Works at Peak and Brow. The best inland section, however, is probably that of Howedale, where almost the entire series may be examined and measured in detail. Beyond this point the Boulder Clay creeps up the hill, and the Alum Shale is not seen again till Pretty House is reached ; where there is a section only a few feet below the Dogger, but not actually showing the junction. The shale has been turned out by rabbits in the woods and fields on the north side of Ramsdale Beck ; and several exposures may be seen in the deep ditches about Park Hill. At Row there is a water- fall cutting into the Alum Shale to a depth of about 10 feet, the Dogger forming the top of it ; and under the old Fylingdales church- yard wall the top of the shale crops out. At Bay Ness, and down the hillside, it can be plainly seen, as in many places there is scarcely 3 inches of soil. The whole of the series may be measured, though not examined, at Normanby Stye Batts ; and from Maw Wyke to UPPER LIAS. 19 Whitby the base of the cliff and the soars consist of this portion of the Upper Lias. One of the most accessible of these coast-exposures is that between Saltwick and Whitby. The general section of this locality iB given in Chap. V, p. 75. The details vary slightly in different parts of the exposure, which explains the somewhat different measurements published by previous observers ; thus, Phillips gives the section as seen at Saltwick, while Tate and Blake, and Simpson, appear to have measured the beds nearer Whitby. After being depressed below sea-level by the great fault at Whitby Harbour, the Alum Shule rises again on the coast about a quarter of a mile before reaching East Kow, where it is seen capped by the Dogger. It continues in the sloping hill for some distance, and is then covered by Boulder Clay, its outcrop in the steep bank on the south side of Mulgrave Woods (Sheet 34, New Series ; 104 SW., Old Series), not being seen. At Rock Head, however, is an old alum quarry, where the upper beds are well exposed, lower beds being seen in the sides of the small streams close by. Hell Scar, near Mulgrave Castle (Sheet 34), is chiefly composed of Alum Shale, the capping of Oolites being very thin ; from the base of this scar to the sea, the bed of the stream is composed of the hard shale below the Alum Shale, a bank of pyritous doggers with the so-called Amm. ovatus (see p. 75) keeping a few feet up in the bank all the way. From Sandsend to the edge of the map, near Overdale, the greater part of the cliff consists of the Shale, but it is only accessible as a rule in the old alum works, such as Sandsend or Lythe. In Eskdale, inland, there is only one exposure on the north side of the river, the Dogger and about 50 feet of the Alum Shale Series, being seen in the small stream that flows down from Aislaby past Woodlands. On the south side there are several exposures ; the first being on the railway embankment in a plantation between Sleights and Ruswarp, where the top only of the Shale is visible. Another section occurs in the small stream below the churchyard at Ugglebarnby. In Iburndale the best sections are — in Little Beck Alum Works ; on the banks of the stream below ; in the neighbourhood of Falling Force ; in Wash Beck ; and at the Thorn Hill works. The Malton road passes over Sleights Brow through a cutting in the lower and harder beds ; while fine sections of the softer part may be studied in the Eskdale Alum Works. Vertebrate Fossils of the Upper Lias. The great excavations of the Upper Lias, both in the Jet Bock ana in the Alum Shale workings, have been very favourable for the discovery of fossils of all kinds, and particularly of the remains of the larger fishes and reptiles, which are difficult to obtain except under such conditions. A large number of the finest specimens of these remains that now adorn our museums were thus procured, and have been subjected to systematic study by many specialists, so that our knowledge of the vertebrate fauna of the Upper Lias is exceptionally advanced. In the case of the material brought together by the early colleotors, the locality is often given Bimply as ' Upper Lias. Whitby,' without discrimina- tion whether the specimen was obtained from the Jet Rock or from the Alum Shale or elsewhere, so that the exact horizon of these specimens is frequently doubtful. So abundant were the reptilian remains in the alum-workings, that the larger vertebra have occasionally been used for bordering garden- paths near the works. J>2 20 LIAS. References to the occurrence of these fossil reptilia date as far back as 1759, while in the middle of last century Owen described many of the specimens in his monographs published by the Palaeontographical Society (1861-1870). . Among the later investigators who have contributed to the subject are J. F. Blake, H. G. Seeley, R. Lydekker, B. T. Newton and D. M. S. Watson. Mr. R. Lydekker's ' Catalogue of the Fossil Reptilia and Amphibia in the British Museum (Nat. Hist.),' published 1888-90, affords a valuable sum- mary of our knowledge to that date. The following list of species is com- piled from it and from later work. » Reptilia or the Upper Lias. Microcleidus [Plesiosaurus] homalospondylus (Owen) macropterus (Seeley) Plesiosaurus longirostris Blake Sthenarosaurus dawkinsi Waison Thaumatosaurus cramptoni {IJarte & Billy) — - propinquus (Blake) zetlandicus (Phill.) Ichthyosaurus acutirostris Owen' latifrons Koenig [== I. longirostris Blake'] tenuirostris Oonyb. trigonodon Theod. [=1. crassimanus Blake"] zetlandicus Seeley Pelagosaurus brongniarti (Kaup) typus Bronn Steneosaurus bollensis (Jaeger) brevior Blake chapmani (Buckl.) minimus (Quenst.) Scaphognathus purdoni E. T. Newton The fish-remains from the Yorkshire Lias have been revised by Dr. A. Smith Woodward in his ' Catalogue of Fossil Fishes in the British Museum (Nat. Hist.), (1889-1901) and in a series of papers (1896-9) in Yorks. Geol. and Polyt. Soc. (see Bibliography, p. 135). The following list is compiled from these works. Fossn. Fishes oe the Upper Lias. Belonorhynchus acutus (Agass.) [? Yorkshire]. brevirostris A. S. Woodw. Caturus sp. Dapedius magnevillei (Agass.) [=D. micans Agass. MS.] Eugnathus latimanus ( Agass.) [=" E. f asciculatus "A.S. Woodw.] Gyrosteus mirabilis A. S. Woodw. Lepidotus semiserratus Agass. " pectinatus " Eg. " rugosus " Agass. ■ Leptolepis saltviciencis Simps. Pachycormus macropterus (Blainv.) acutirostris A. S. Wooiw. curtus Agass. Pholidophorus germanicus Quenst. Ptycholepis bollensis Agass. Saurostomus esocinus Agass. 4. Blea Wyke Series — Except in the neighbourhood of Peak, the Alum Shale Series forms the top of the Upper Lias and is imme- diately overlain by the Dogger which is the lowest part of the Lower Oolite, there being in some places indication of slight erosion of the underlying beds and of a gap in the sequence before the Dogger was deposited. East of the Peak Fault, however, the conditions are curiously different ; at least 120 feet, or perhaps nearly 200 feet, of strata being present in the coast-section above the Alum Shale Series that are not known to be represented in any other part of the district, BLEA WYKE BEDS. 21 There has been much discussion and difference of opinion as to the classification of these interpolated beds ; and the position within them of the boundary between Upper Lias and Lower Oolite has been variously defined. An outline of this discussion will be found in Chap. V (p. 78) and an earlier summary of the literature pertaining to it is contained in the official memoir on ' The Jurassic Rocks of Britain : Yorkshire,' vol. i, pp. 147-153. In the previous edition of the present memoir, most of the beds in question were classed with 'The Dogger' and therefore with the Lower Oolite, only the lowest bed of dark grey shale (the ' Amm. striatulus ' beds of the section given below) being brought in as Lias ; but later palseontolo»ical investigation has suggested that the limits of the Upper Lias should be carried higher and should include most of the sandy beds of the Blea Wyke section (see p. 79). On the map, however, the boundary is drawn as defined in the previous memoir ; with some practical advantage, inasmuch as it marks approximately the upward limit of the shale-deposits. Part of the series above the Alum Shale has been known as the ' Zone of Amm. jwrensis ' or as ' Zone of Amm. striatulus,' but the limits assigned to the zone have been somewhat indefinite. From the local occurrence of the Blea Wyke beds only on the east side of the Peak Fault it has been surmised by some investigators that the westward uplift at the fault was already in progress during the deposition of these deposits 1 ; but there has been also adverse criticism of this view (see Chap. V, p. 82). The succession of the Blea Wyke beds, downward from a ferru- ginous band recognised by all authorities as pertaining to the Lower Oolite, is shown in abstract in the following section (fuller details are given in Chap. V, p. 79) : — Lower Oolite. ' Upper Lias. ( Section at Blea Wyke. Ft. in. C Hard red ferruginous sandstone ... ... ... 10 ' The ) ' Nerinsea-bed ' ; ferruginouB bund composed Dogger.' 1 mainly of shells with the lime nearly all V. replaced by iron ... ... ... ... ... 1 6 Greenish dogger sandstone, with small nodules or ' pebbles,' scattered and in bands ... ... 25 Ferruginous micaceous shaly band; very few fossils ... ... ... ... ... ... 1 2 ' The Brown sandstone, crowded with Terebratula ... 2 Yellow ( Soft brown sandstone, becoming yellow in lower Beds.' part, with ' pebbles ' scattered throughout ; fossils in clusters here and there, including casts of large phragmacones of belemnites ... 25 ' Serpula-bed ' ; soft grey sandstone, forming base of cliff and upper surface of scar at Blea Wyke Point ; fossils in clusters ... ... ... ... 10 ' The J Soft sandstone and hard grey sandy shale ; fossils Grey S in clusters, including wood and phragmacones Beds.' of belemnites ... ... ... ... ... 25 ' Lingula-bed ' ; soft grey sandy shale, with a band of ferruginous sandy nodules at base con- \ tain in g IAngula beard Phill., in abundance ... 7 Dark grey argillaceous shales with ironstone doggers, known as the ' Amm. striatulus beds ' ; shown as the top beds of the Lias on the map. 1 W. H. Hudleston, Proc. Geol. Assoc, vol. iii, p. 304. R. H. Rastall, Quart. Journ. Geol. Soc, vol. lxi, p. 457. *$ Lias. With regard to the dark, shales at the base of, and immediately below, this section there has been much confusion, owing in part to the obscurity of the lower part of the cliff by heavy talus. In the later reading of the section by Mr. S. S. Buckman (see p. 80) a thiek series of ' Peak Shales ' is recognised between the ' striatulus beds ' and the Alum Shale Series ; and the thickness of the Upper Lias as a whole in this quarter is correspondingly increased. These beds are probably in part included in the bottom bed of the following section, measured in the Peak cliffs and published by Fox-Strangways in his memoir, ' The Jurassic Rocks of Great Britain : Yorkshire,' vol. i, p. 136:— "Section of the Striatulus-fteds or Zone of Ammonites jurensis at Peak." ft. in. " Impure ironstone band ; apparently corresponding with the lowest of the Blea Wyke Beds. Shales ... Calcareous band. Shales ... Calcareous band, cemeutstone. Shales .... Calcareous band. Shales with nodular band . . . Nodular bands made up of small nodules. Shales with nodular and jetty bands, containing Am. striatulus, Trigonia literata, Belemnites Shales with Am. variabilis, base hidden by debris on the shore The ' Grey Beds ' of the Blea Wyke section represent lithologically a passage from the more argillaceous shales below them to the thick sandstones above. In places they contain numerous fossils, some of which are mentioned in Chap. V, pp. 79-80 ; the fuller (compiled) lists will be found in the memoir last referred to. The ' Yellow Eeds,' with which may be considered the greenish sandstone above them, consist mainly of soft unevenly-bedded sandstones, more or less ferru- ginous, with few fossils except in certain bands and patches. The majority of the pebble-like lumps included in these beds appear to be the relics of worn nodules, perhaps originally phosphatic, though now with a hard crust only, and much decomposed in the interior. They indicate current-action on the sea-floor during the deposition of the beds. All the beds appear to become thinner iu the steep cliffs to the northward of Blea Wyke, so that below Peak Hall, where they are again accessible, there are not more than 15 feet of the ' Grey Beds ' and 20 feet of the ' Yellow Beds ' ; and a little farther west, beyond the Peak Fault, they have disappeared entirely. 9 6 15 25 12 12 0" 23 CHAPTEK III. LOWER OOLITE. The Lower Oolite formation of the Yorkshire basin consists, as mentioned in Chap. I, of three or four groups of estuarine strata separated by limestones or thin calcareous beds which have been formed under marine conditions. These marine beds are irregular in their development and occasionally thin out altogether ; thus the Millepore Bed is not known along the northern outcrop, while the Grey Limestone is absent in the south of the county. In the area under description, the formation comprises (cf. ' Table of Strata ' p. 6), in ascending sequence, The Dogger (marine) ; Lower Estuarine, with (marine) Eller Beck Bed; Millepore Bed (marine) ; Middle Estuarine ; Grey Limestone (marine) ; Upper Estuarine ; and Cornbrash (marine). The correlation of these beds with their equivalents in other parts of England is rendered difficult by reason of their wide difference in lithological characters and mode of origin. In the south of England the beds of this age consist almost wholly of sediments deposited under marine conditions, except that the Stonesfield Slate and Forest Marble, and, in the Midland counties, the Lower and Upper Estuarine Series, to a certain extent denote the presence of neighbouring land. The Lower Oolite occupies the whole of the coast between Blea Wyke Point and Scarborough, though south of Long Nab near Oloughton it is much obscured by drift. The bold cliffs between Blea Wyke Point and Cloughton Wyke reveal a magnificent section of the succession upward from the Dogger to the Moor Grit which forms the basal portion of the Upper Estuarine Series, while the upper portion of the latter series is more obscurely seen in a few places in the cliff, and more extensively on the shore, between Long Nab and Scarborough. The Cornbrash does not reach the coast except in the North Cliff, Scarborough, at and just beyond the southern margin of the map, and is rarely visible there owing to the tumbled ground and artificial works. One of the best opportunities for examining and measuring the beds from the Moor Grit downward is afforded by the great cliffs above and south of Blea Wyke, where the downward succession may be averaged as follows : — Lower Oolite in the clipjs neak Blea Wyke. Ft. In. Upper Estuarine f Moor Chit .- massive false-bedded sandstone Series (lower part). \ resting on flaggy sandstone ... ... 40 Grey Limestone C Sandy and calcareous shale resting on Series. (. bands of impure limestone ... 100 24 LOWER OOLITE. Ft. In. Middle Estuarine Series. Millepore Bed. Lower Estuarine Series, with Eller Beck Bed. Dogger. C Shales and false-bedded sandstone, with < occasional beds of fireclay and a thin seam C of coal in the lower part ... {Nodular bands, with calcareous and ferru- ginous sandstone below ( Great masses of false-bedded ferruginous sandstone resting on shales, with bands of carbonaceous matter Eller Beck Bed : thin flaggy sandstone rest- ing ' on a few feet of soft shale enclosing thin bands of ironstone Principally carbonaceous shales, with thin coal seams in the upper part, false-bedded sandstones in the lower f Hard ferruginous sandstone with Nerinsea- ( bed at base, see previous section, p. 21 ... 100 8 110 15 150 11 6 Both in composition and thickness the subdivisions vary from place to place, and the formation as a whole probably reaches its maximum thickness in the neighbourhood of the above section. Further description and local particulars of the different members of the sequence are given below under their respective headings. The Dogger. As previously stated, the Dogger has usually been held to include the greater portion of the sandy ' Blea Wyke Beds ' now assigned to the Upper Lias (see Chap. V, p. 78). Excluding these beds, the bottom of the Dogger in the Blea Wyke section is marked by the con- spicuous ' Nerinsea bed,' a hard ferruginous band, crowded with the ferruginous casts of shells, which forms a capping to the underlying greenish sandstone (see section, p. 79). The band is not known to occur except in this local association with the Blea Wyke Beds, and it evidently marks peculiar conditions of accumulation which were limited in range. It is the principal source of the fossils recorded from the Yorkshire Dogger, and is particularly rich in gasteropoda, among which Nerinwa cingenda PhilL, from which the bed is named, is very abundant. A full compilation from the numerous published lists of the fossils is given in the general memoir on ' The Jurassic Rocks of Britain,' vol. i, pp. 177-8, and vol. ii, pp. 143-185 (Mem. Oeol. Surv.). The following short list, from the species recorded by Hudleston (Proc. Geol. Assoc, vol. iii, 1874, p. 300), will serve to illustrate the general character of the fauna : — Fossils from the 'Nerinwa bed.' Hinnites velatus P Ooldf. Gervillia tortuosa Sow. Pteroperna striata Bean MS. Modiola cuneata Sow. Cucullaea cancellata Phill. Macrodon Hirsonensis d' 'Arch. Trigonia denticulata Ag. V-costata Lycett. spinulosa T. and B. Cardium acutangulum Phill. Tancredia axiniformis Phill. Cardium striatulum Sow. Opis Phillipsii Mor. Astarte elegans Sow. Ceromya Bajociana D'Orb. Gresslya abducta Phill. Natica adducta Phill. punctura Bean Ohemnitzia lineata Sow. Nerinsea cingenda Phill. Cerithium (two species) Alaria Phillipsii D'Orb. Onustus pyramidatus Phill. Nerita laevigata Phill. Trochotoma -Actseonina tH£ DOGGER. 25 The lO-ft. bed of very ferruginous sandstone above the NerinsBa- band is most accessible on the southern side of Blea Wyke Point, where it forms a bold reef that stands out conspicuously amid the fallen blocks covering the shore. The rock breaks up into irregular masses separated by seams filled with brown oxide of iron, in a manner which is very characteristic of the Dogger in general. It contains fragments of quartz scattered throughout ; the irony matter in the rock is frequently aggregated together in nests, which are harder than the sandstone, and stand out in small projections that give it a rough irregular appearance. This portion of the Dogger is continued to the north and may be traced from Blea Wyke along the top of the lower cliff to the great exposure near the fault below Peak Hall. Here the reddish-brown ferruginous rock, much fractured and traversed by diagonal seams of oxide of iron, thickens out rapidly and appears either to lie in a hol- low of the lower beds or to indicate a local passage of these beds into the ferruginous rock ; but it is not easy to determine the conditions exactly, owing to the fallen blocks which obscure this part of the section. When the Dogger appears again on the opposite side of the great Peak Fault it is much reduced in thickness. At the Alum Works, which are only half a mile from the exposure in the cliff, the section is: — Section at Peak Alum Qtjarri (east end). . Ft. In. Ft. In. Massive sandstone with carbonaceous matter in lower part (Bstuarine Series). f Soft irregular ferruginous sandstone ... 1 to 1 4 Irregular band of concretions or small nodules 1 to 4 Ferruginous calcareous sandstone, vertically jointed, with white specks, and a very few 9 bo Ml fl( small nodules 1 8 to 1 10 Band full of nodules or concretions, con- taining Terebratula and other bivalves ... 06 Calcareous concretionary sandstone with some shale, becoming more like separate nodules at south end of quarry 1 1 6 Blue shale (Lias). Average thickness, about 5 For some distance beyond this section the rock maintains much the same appearance, weathering into rounded lumps or doggers, enclosed in a ferruginous crust. Its outcrop is easily traced westwards, as far as Howedale Beck, after which it becomes obscured by Boulder Clay. No fossils were observed in any of the exposures along this part of the outcrop. In the small stream near Pretty House the typical fer- ruginous sandstone crops out, and is about 12 feet thick, but apparently unfossiliferous; from this point it is not seen again till RamsdaleBeck is reached, where from the smallness of the exposure its thickness cannot be exactly ascertained. Its junction with the Lias is cut through at Bow, and in the road above Park Hill, in both of which sections the Dogger is about 18 inches thick. 'Mr. Hudleston includes this bed in the Lias. Proc. Oeol. Asioc, vol. iii, p. 303. 26 LOWER OOLITE. The Dogger reaches the cliff again at Hawsker Bottoms, and can be examined and measured on the pathway down, known as Sawdon'i road or Jackass road, where the following section may be seen : — Cliff-section at Hawskek Bottoms. Estuarine C Alternating sandstones and shales, three small coal Ft. In. Series. (. seams near the base ... ... ... ... ... 80 /"Typical dogger-sandstone with pebbles, casts of tj ) belemnites, and shell -fragments ... ... ... 5 .0 °** ' 1 Band of small nodules or pebbles , 2 (, Massive ferruginous concretionary nodules ... ... 1 Continuing in the cliff north-westward at only a few feet above bigh-water mark, the outcrop passes beyond the margin of the area of Sheet 44 and enters that of Sheet 35 (New Series) where it presents the following section, the base of the Dogger being here about 10 feet up in the cliff : — Cliff-section about 1 mile S.S.E. of Whitby High Lighthouses. / Sandstone Ft. tn. 20 20 4 3 3 3 8 Estuarine J Dark shales and thin sandstone Series. S Coal... [ Sandstone (carbonaceous root-marks)... ("Ferruginous sandstone ... Dogger. < „ „ with pebbles . . . (.Nodular band Lias Alum shale. The section remains the same as far as the lighthouses, where a thick mass of false-bedded sandstone descends and cuts out the Dogger for a few yards. In Saltwick Bay the Dogger is 2 feet 6 inches in thickness, very hard, and with less silica than usual. At the base there are many of the so-called pebbles, some of which are waterworn fragments of belemnites and ammonites, some of the latter appearing to be Lower Lias forms. 1 Approaching Whitby, the Dogger becomes still more ferruginous, nodule3 of ironstone appearing above the main part of the bed ; still it is too siliceous to be of commercial value as an ironstone. Just before reaching Whitby, another example of local unconformity at the top of the Lias is revealed in the cliff-section. After the Dogger was deposited, a small bollow has been eroded by current- action through it and for a few feet down into the Lias, and was after- wards filled up by sand which now forms the sandstone at the base of the Estuarine Series. From this point the Dogger rises in the cliff till it is about 40 feet up near the East Pier ; then turning south round the prominence, it descends rapidly to the river-bed inside Whitby Harbour. The Dogger is thrown down below sea level by the large fault that runs through the harbour, and is not seen again till it crops out a little way inland from the mouth of Raithwaite Gill two miles west of Whitby. Here the bed was formerly worked on a small scale by an 1 The supposed Lowei Lias age of these fragments was stated more positively in the former edition of this memoir ; but, in view of the results of the later re-investigation by Mr. B. S. Henies {Proc. Oeol. Asioc, -gpl. xix [1906], p. 423), and of the fact that the specimens on which the statement was based have not been preserved, it cannot be insisted on. THE DOGGEit. 27 adit ; but is now entirely obscured by slips of boulder-clay. The part of the bed worked appears to have been the bottom nodular band of the next section ; but its unreliability, both as regards quality and thickness, caused the work to be abandoned. For a short distance west of Raithwaite Gill, the Dogger continues in the face of the cliff, and the following section was measured in this neighbourhood east of the high road : — Section west or Raithwaite. Sandy calcareous ironstone with ferruginous joints... Calcareous and ferruginous sandstone, many pebbles Concretionary 'ferruginous sandstone, pebble bed ... Ferruginous pebbly sandstone, pebble bed Ferruginous calcareous sandstone , Very hard nodular ironstone Red ferruginous shale passing to Alum Shale. The outcrop then swings inland, but is completely obscured for about a mile and a half, till it reappears in the bed of the little stream west of Dunsley, just at the edge of the map. Better exposures are seen in the stream that has cut out Trucky Rock Hole, just outside the present map (Sheet 35). Here the Dogger consists of two beds, both very hard and solid, weathering into rounded blocks with ferru- ginous casings. The upper bed is a red ferruginous sandstone ; the lower is of a much lighter colour, more calcareous and contains many fossils, though, as a rule, only a few species, such as Terebratula ' triUneata ' (see p. 82), Pholadomya, Trigonia, &c. The Dogger caps the Alum Shale at Hell Scar, due south of Mul- grave Castle (just outside the map), and from this place the outcrop is sufficiently clear as far as the Lythe Road, where a small tongue of clay obscures its course just before its appearance in the Alum Works, near Sandsend. Here is one of the most accessible of all the sections of the Dogger. The following details were measured at the south end of the great quarry : — Section at the Alum Works neak Sandsend. Ft. In. (Ferruginous jointed concretionary sandstone ... 2 6 Ferruginous shale ... ... ... ... ... 10 Dogger band 1 Ferruginous shaly sandstone, pebbles ... ... 1 8 Ferruginous sandstone, weathering into large blocks 4 6 10 6 The lower part of the bottom bed contains many pebbles and fossils, the latter chiefly in nests. Terebratula ' trilineata ' occurs in vast numbers, the less common fossils being Lingula, Vermetus, &c, all occurring as casts, and not easily determinable. To the north of this section the Dogger becomes thicker, and less ferruginous ; in fact, a sandstone, having a slightly oolitic appear- ance. There are ferruginous nodules at the top and base, and ' pebbles ' throughout. 28 LOWER OOLttM. West of Overdale Wyke, the cliff near its most northerly point on the map presents the following section : — Duff-section near Overdale "Wyke. Ft. in. 40 50 5 1 6 1 8 4 f Massive false-bedded sandstone Estuarine J Shale, carbonaceous, with soft jet Series, j Sandstone ... (^Carbonaceous shales ... f Ferruginous shale... Dogger. < Slightly ferruginous sandstone, pebbles (. Shale, with two rows of ironstone nodules In the interior country, the Dogger crops out on both sides of Eskdale in the north-west corner of Sheet 44. Between Kuswarp and Sleights it is first seen in a small stream near the railway, and again in an old quarry a few yards off, where it is about 8 feet thick ; but the outcrop is then hidden by Boulder Clay until Ugglebarnby in Iburndale is reached. In quarrying stone to build the churcb at Ugglebarnby the upper part of the Dogger was exposed. A trial-hole was driven into it, but the rock proved valueless as an iron-ore. At Little Beck Alum Works, and along the east side of Iburn- dale as far as Falling Force, very fine exposures occur ; here the sandstone is full of soft white specks, and it contains sufficient car- bonate of lime to effervesce with acid. The number of fossils in it, especially in the lower part, is considerable ; but as they are generally casts their specific identity is uncertain ; some may be derivatives. Lingula is very abundant, as is also Terebratula ' trilineata.' Two species of Pecten, two of Trigonia, a Nerinaea, occasional casts of an ammonite, .and fragments of belemnites' are among the more common fossils. The thickness of the Dogger at the Alum Works is about 15 feet. 1 On the west side of Iburndale an interesting section is seen in Wash Beck, the central portion of the Dogger, being a coarse siliceous grit. The other exposures are at the Thorn Hill Alum Works, and at the road-side above Sleights. At the Alum Works in Eskdale, south-west of Sleights, the Dogger is about 12 feet thick, and has often been tried as an iron-ore, but without success. The only section on the north side of the Esk is in the small stream that flows down from Aislaby past Woodlands, and shows the following details : — Section near Aislaby. /"Typical Dogger sandstone Doeeer J Soft sandy shale fifi J Whitish sandstone ; f ossiliferous in lower part, 7 C mostly casts ; Trigonia, Pholadomya, etc. j * Some of these inland sections have been re-described by Mr. B. H. Rastall, Quart. Journ. Geol. Soc, vol. lxi (1905), p. 453. LOWER ESTUARINE SERIES. 29 There are clear indications, both in the variability of the deposit and in its relations to the underlying strata, that the Dogger was accumulated in shallow water swept by strong local currents. Under these conditions; as pointed out by Prof. J. F. Blake, 1 fine sediments on the sea-floor may be swept away and their residual organic contents mingled with the fauna of a somewhat later stage. The characters and mode of occurrence of the irregularly distributed fossils in the Dogger at most of the localities above-described are strongly suggestive of this kind of local concentration, while evidence for the non-deposition or removal of earlier strata is shown by the absence of the Blea Wyke beds and underlying portion of the Upper Lias in every part of the district north of Peak. In the country west of the area now described, the hiatus at the horizon is still more strongly developed, so that in Bilsdale the base of the Dogger descends in one place to within 30 feet of the Jet Bock. 2 In a later chapter, Mr. Buckman, in discussing this relationship, suggests that the Lias had been thrown into local undulations by slight earth-movement before the Dogger was deposited (see p. 82). Lower Estuarine Series and Eller Beck Bed. In their lithological characters, the Estuarine Oolites of Yorkshire bear a close resemblance to the Carboniferous Coal Measures, for they consist mainly of masses of shale and sandstone, and are subject to much local variation. The sandstones, being generally arranged in huge wedges or lenticles, are rarely persistent horizontally for more than a short distance, though they occur more commonly in some parts of the series than in others. The series also includes occasional thin coal-seams which, like the sandstones, have no individual persistence over a wide area. Like the Coal Measures, too, the beds in some places contain numerous plant-remains ; these fossils have proved of extreme interest to the palaeobotanist and have formed the subject of an extensive literature which is dealt with in another part of the present memoir (Chap. VI, p. 103). The Lower Estuarine Series, lying between the Dogger and the Millepore Bed, attains its maximum known thickness in the neigh- bourhood of Peak. Farther north, the Millepore Bed has not been found, and, in its absence, the upper boundary of the Lower Estuarine subdivision cannot be traced. The Eller Beck Bed which occurs near the middle of the Lower Estuarine Series is often strongly ferruginous, but is distinguished mainly by the presence of marine fossils which indicate a wide incursion of the sea over the shallows of the great estuary. Other- wise, in lithological composition the bed is not conspicuously differentiated from the series above and below it. 1 'On Aggregate Deposits and their Relation to Zones,' Oeol. Mag., dec. iv, vol. v, pp. 481-8. » ' Geology of Bskdale, Rosedale, &c. (Sh. 96 N.E.),' Mem, Oeol. Sum., 1885, p. 25, 30 LOWEK OOLITE. The following section, measured in the cliffs above Blea Wyke, shows the details of the whole series at this locality : — Lower Estuarine Series in the Cliff near Blea Wyke. Ft. In. 60 0\ 8 9 2 20 1 9 « 4 10 Massive false-bedded sandstone, very ferruginous Light sandy shale... Hard white stone ... Dark shale with underclay Shale with carbonaceous bands Hard white stone ... Shale Coal Seam, very impure ... Rubbly flaggy sandstone... Eller Beck Bed : thin flaggy sandstone resting on a few feet of soft shale enclosing thin bands of iron- stone Shales, soft and light coloured, with a band of ferru ginous nodules containing plant remains Carbonaceous shale Shale, rather sandy Carbonaceous shale Very hard sandstone Shale, soft and soapy to the touch Sandstone, somewhat flaggy Shale Sandstone ... Dark shale ... :.. Shale with thin bands of very hard stone Coal Seam Underclay ... Soft ferruginous sandstone, with vertical stems of plants, probably Eguisetites, often 5 feet high Shale, soft and light coloured Coal Seam Sandstone, soft and rubbly Coal Seam Shale, dark coloured Sandstone, coarse grained, ferruginous, and false bedded Shale, dark coloured Besting on the Dogger Sandstone (see p. 21). Ft. In. Ill 1 15 20 1 *■' 20 2 2 8 5 5 3 3 30 6 ) 159 11 2 12 4 2 2 3 6 24 10 Oj Total 286 As will be seen from the above section, sandstones predominate in the upper portion of the series, above the Eller Beck Bed, and shales in the lower portion ; this being the general condition throughout the district. Southward the series continues to occupy the greater part of the cliff to the headland beyond Hayburn Wyke, but sinks below sea- level at Cloughton Wyke and is not exposed again in this direction within the limits of the present map. Northward from Blea Wyke it swings inland at Peak under the influence of the big fault, and after sweeping around the amphitheatre of Robin Hood's Bay, reaches the coast again near Hawsker and is practically continuous in the cliffs thence to Whitby. It is, however, thinner here than at Blea Wyke, both in its upper and lower portions. At Hawsker there is little more than 100 feet of strata between the Eller Beck Bed and the St. In. 15 20 4 3 LOWER ESTUARINE SERIES. 31 Dogger ; but as the Millepore Bed has died out here, the Lower and Middle Estuarine series cannot be separated ; the thickness of the combined series, up to the Grey Limestone, is about '285 feet. In the Hawsker district a seam of coal, usually about four inches, occurs about three feet above the Dogger. The following section in the cliff at Nype Howe shows the position of the seam : — Estuarine Semes in cliff near Nype Howe. Sandstone ... Dark carbonaceous shale... Coal Seam Sandstone, with roots (P) converted to jet on Dogger. This thin coal can be seen at the top of the cliff immediately norLh of Normanby Stye Batts, and continues without interruption beyond High Whitby lighthouses. Other thin seams occur in this lower part of the series, but as a rule they are continuous only for a short distance. In the cliffs between Hawsker and "Whitby, though sandstone pre- dominates, there are remarkable variations in the series ; the entire cliff at Widdy Field consists of shale with a few thin beds of sandstone, while between Whitby and Saltwick tbe cliff consists chiefly of sand- stone. Young and Bird mention 1 that in 1826, " an immense mass of the upper part of the cliff between* Whitby and Saltwick fell down, and the poor people of Whitby found some tons of good coal among the broken strata." An interesting feature of the Estuarine Series is the occasional presence of footprints of saurians, first discovered by Mr. H. Brodrick, in 1907-8, in fallen blocks of sandstone on the shore at Saltwick, and described and figured by him in 1909. 2 The exact horizon from which these blocks had fallen could not then be ascertained, though it was clear that they were from the Estuarine beds. A year or two later the bed from which the blocks had fallen was found in situ by Prof. P. F. Kendall, to whom we are indebted for the following details of his discovery. The bed outcrops on the path descending from the cliff-top to Salt- wick Bay, and its position can be fixed by the aid of a bed of coaly shale. The cliff is capped by boulder-clay which rests on a fairly thick bed of flaggy sandstone, with 11 feet of thin shales and sand- stone below. Then follows the coaly shale referred to, which overlies some 8 feet of shale forming a sloping bank and resting directly on the bed of sandstone, about 1£ feet thick, containing the footprints. Below the footprint-bed there is about 9 feet of shale and then another band of sandstone and sandy shale, the latter containing Williamsonia. Beneath this is another bed of shale, 12 feet thick, again forming a sloping bank; at the foot of this is the Dogger, with- the Upper Lias below. The top of the shale beneath the footprint-bed was found to contain a species of Unio, which has been described by Mr. J. W. Jackson 3 as Unio kendalli. Mr. Jackson also mentions the occurrence of Unio 1 ' Geological Survey of the Yorkshire Coast,' 2nd ed, 1828, p. 121. ! ' Note on Footprint Casts from the Inferior Oolite near Whitby, Yorks.' Proc. Liverpool Cfeol. Soo., vol. x, 1909, pp. 327-335, with figs. & plates. See also Naturalist, Aug., 1908, pp. 300-1 ; and 85th and 86th Ann. Reps. Whitby Lit. # Phil. Soc, 1908-9, pp. 8-9 & 6-7. « Naturalist, June, 1911, pp. 2U-214, pi, xiv, 32 LOWER OOLITE. at Brow Alum Quarry on the southern side of Robin Hood's Bay, in a bed only Ik feet above the top of the Dogger, and of other specimens in the Lower Estuarine beds at Hayburn Wyke. Another discovery of footprints in situ, this time in the Upper Estuarine Series, 3 miles north of Scarborough, will be subsequently referred to (see p. 44). The cliffs immediately east of Whitby reveal thick wedges of sand- stone, containing much ' soft jet ' or fossil-wood ; and these wedges are seen to cut into the previously-deposited beds of shale, indicating strong occasional currents, probably due to floods. A considerable quantity of ' soft jet ' was found when the cutting was made for the road from the pier to the west cliff, at a horizon rather more than 50 feet below the Grey Limestone Series ; and similar material occurs at about the same horizon in the cliff-section at Hawsker. These beds probably belong to the Middle Estuarine Series ; but, as already mentioned, the Middle and Lower divisions are inseparable north of Robin Hood's Bay. Good exposures of the combined series are visible in Raithwaite Gill, two miles west of Whitby, and in the streams south of Mulgrave Woods. A deep boring near Ruswarp, made in the year 1821, penetrated over 200 feet of the Estuarine Series before reaching the Dogger, and passed through three thin coal-seams, respectively 5 inches, 4 inches, and 11 inches thick, a little above the base of the series, and two similar thin seams in the higher part ; the details of the section, recorded in mining idiom, were first published by Young and Bird, 1 and have been twice reprinted by the Survey 2 , so that they do not require further repetition. Allowing for the height to the top of the series above the site of the boring, the total thickness of the combined Middle and Lower Estuarines at this spot is about 270- feet. A second boring four miles farther south, at Maybecks, near the head of Little Beck, indicated that the two series at this point are over 300 feet in thickness. 3 Inland, around the head of Iburndale and in Ramsdale, SW. of Robin Hood's Bay, the series is well exposed along the stream-courses, the alternation of shale and sandstone giving rise to some small water- falls. The average composition of the strata between the Eller Beck Bed and the Dogger in this quarter is given in the following section, which is approximately that seen along the steep eastern bank of Little Beck (Drarndale), north of Palling Force. The thicker sand- stone of this section is unusually persistent, and is the source of much of the building-stone of the district, the well-known Aislaby quarries being in the lower part of it. Section in Lower Estuarine Series west op Robin Hood's Bat. Eller Beck Bed at top Ft. In. Shales, very variable, average... ... ... ... 15 Sandstone, varies from 20 to 60 ft. ... ... ... 60 Shale, increases as the sandstones diminish... ... 15 Sandstone, in very irregular wedges ... ... ... 20 Shale, often carbonaceous ... ... 10 Besting on Dogger. Total 120 1 ' Geological Survey of the Yorkshire Coast,' 2nd ed, 1828, p. 124. J< Geology of North Cleveland,' Mem. Qeol. Surv., 1888, p. 46; and 'Jurassic Bocks of Britain, vol. i, Yorkshire,' ibid., 1892, p. 185. ' * ' Jurassic Bocks, &c.,' op. rapra cit. p. 487, great Area, 3 3 3 I 6 3 17 3 ELLEB, BECK BED. 33 Eller Beck Bed. — This term was applied 1 to a thin and variable belt of marine deposits in the Lower Estuarine Series, because of its typical development in an exposure along the Eller Beck below Darn Holm, near Goathland, in Sheet 43, slightly beyond the western limits of the area now under description. Its boundaries are often not well defined, as they depend mainly upon the presence or absence of marine fossils which are irregularly distributed ; but s there is almost constantly a flaggy sandstone at the top of the belt. The most southerly point on the coast at which the Eller Beck Bed appears is about a mile north of Oloughton Wyke, where it rises from the sea in a reef called Iron Scar. The components of the bed at this place are as follows : — Eller Beck Bed north or Olotjshton Wyke. Ft. In. Sandstone, close-grained in upper part, and flaggy with streaks of dense ironstone near the base ... ... ... 12 Thin band of ironstone with JSfucula, Astarte in numbers, also Oervillia tortuosa (J. de (J. Sow.), Gorhula, Tancredia and Littorina Shales, well-bedded and ferruginous Thin band of ironstone, unfossiliferous. Shales, similar to above ... Ironstone Total The composition of this marine bed remains practically the same in the cliffs to the northward, the belt being easily traced at the top of the undercliff between Hayburn Wyke and the Peak, up to the great Peak Fault, where the Estuarine series swings inland until Robin Hood's Bay is passed. Where the series reaches the coast again near Hawsker, the Eller Beck Bed reappears in the face of the cliff immediately on the north of Maw Wyke, from which point it continues to High Whitby, and after turning inland for a short distance once more reappears., just north-west of Saltwick Nab. From this point it continues to the mouth of Whitby Harbour, where it is the capping rock of the East Cliff. There, it is roughly 100 feet above the Dogger, and consists of thin fissile sandstone, underlain by ferru- ginous shale. The shale contains nodules in which the relics of small marine shells are found. A clear section occurs close to the top of the cliff on the east side of the Esk at Whitby, near the Church steps. West of Whitby the marine band is not seen again in the neigh- bourhood of the coast within the limits oi Sheet 35, but is visible in the vicinity of Kettleness, about a mile within the adjacent Sheet 34. In the interior south of the Esk the Eller Beck Bed forms a very convenient horizon in the thick series of Estuarine Beds. It is prob- ably continuous, for wherever sections occur in the right place there is little difficulty in recognising the belt. Throughout a great part of this district it is composed mainly of flaggy fossiliferous sandstone, and sometimes oolitic ironstone, resting on shales in which occur either nodules or thin continuous beds of very fossiliferous ironstone. Both its upper and lower boundary are indefinite, there being a gradual passage into the ordinary Estuarine beds. 1 G. Barrow, ' On a new Marine Bed in the Lower Oolites of East Yorkshire,' Geol. Itfac/., dec. ii, toI. iv, 1877, pp. 552-6. 34 LOWER OOLITE. The most easterly exposure south of the Esk valley is in a little stream that flows into the Little Beck Alum Works. The section here is as follows : — Eller Beck Bed, near Little Beck. Ft. In. Sandstone, flaggy and micaceous, splits to very thin laminae in lower part Shales, sandy in upper part, bluish-grey below Sandstone, carbonaceous, and containing occasional ferru- ginous nodules composed of shells in the middle ... Ferruginous sandy shale Ironstone with Pholadomya Ferruginous shale... Ironstone casings with liquid mud inside Total The ironstone nodules in the middle of the second band of sandstone contain nearly the same fossils as the ' Pholadomya ironstone ' below. The chief are a small Oryphcea, Astarte, Oardium, Avicula, Oervillia, Cerithium, and a few others. Slightly above Falling Force, near. Old May Beck, the hard sand- stone that forms the top of the last section may be seen dipping into the stream, but the shales and fossiliferous layers are completely covered by debris. A full list of fossils from the Eller Beck Bed and from its equivalent, the Hydraulic Limestone of the Howardian hills, is contained in the general memoir on the Jurassic rocks of Yorkshire. (Vol. i, p. 205.) Millepoee Bed. This marine band, dividing the Lower from the Middle Estuarine Series in the southern part of their outcrop in Sheet 44, is often styled the Millepore ' Series,' and perhaps more correctly, as it generally includes several distinct strata differing to some extent in composition. It has received its name from the little polyzoan, Entah- phora [Spiropora, Cricopora, or MiUepora] straminea (Phill.), frag- ments of which in some places occur profusely on the surface of the rock. The name appears to have been first published by Wright 1 in 1 860, though in common verbal use before that time. Oh the coast the rock is not a true limestone, but has more the nature of a very hard and siliceous calcareous sandstone with ferru- ginous partings. The exposed situations which it occupies on the shore, and the manner in which it forms as it were a breakwater to the softer strata behind, testify to its exceptionally hard nature. It is a false-bedded partly oolitic rock, full of the remains of polyzoa, echinodermata, &c, in a fragmentary condition, and has every aspect of having been formed in comparatively shallow water. North of Scarborough the Millepore Bed first appears above the level of the water at the north side of Cloughton Wyke, where it forms a conspicuous reef of massive sandstone, about 10 ft. thick, which is covered at high water. The rock is here more ferruginous and much less calcareous than in its outcrop around Gristhorpe Bay (Sh. 54) to the south of Scarborough ; and what little lime remains seems confined to the upper portion, which also is the fossiliferous part of the bed. As it rises in the cliffs farther to the north it 1 Quart, Joum. Geol. Soc. f vol. xvi, p. 17, MILLEPORE BED. 35 becomes even more arenaceous, and about Staintondale nothing remains but a few inches of rotten ferruginous beds with imperfect fossils, which finally appear to pass into unfossiliferous sandstones. Hudleston 1 considered that the peculiar nature of the bed at Cloughton is due principally to subsequent alteration, by which the lime originally in the rock has been in great part replaced by iron. In the cliff south of Hayburn the Millepore Bed is not very easy to follow, but the red ferruginous sandstone of which it principally consists may be seen here and there peeping out between the vegeta- tion. From this sandstone we obtained Ceromya bajociana d'Orb, Modiola imbricata J. Sow., and a Pinna. At Hayburn, the ground being covered by Boulder Clay, and also probably faulted, the outcrop which here turns inland becomes uncertain, and can only be inferred from the position oi the beds above. Where the bed swings back to the coast, about half a mile south of Petard Point, a little ferruginous sandstone, containing casts of fossils, crops out in the cliff-edge ; and from this point northwards it may be seen at intervals near the base of the upper cliff. About 500 yards south of Blea Wyke, where the word ' Spring ' is written on the six- inch map, is the following section : — Millepore Bed near Bi.ea Wyke. Shaly sandstone, very ferruginous ... .., Three bands of ironstone in very ferruginous sandy shale... Sandstone, calcareous at top and very ferruginous through- out; probably Total The lowest of the three bands of ironstone in the above section contains a considerable number of fossils. The chief are Modiola imbricata J. Sow., Trigonia reeticosta Lye, Unicardium?, Area, and Cucullcea. The upper few inches of the bottom sandstone are so calcareous as to pass almost into a ferruginous sandy limestone ; fragments of crinoids occur in it in some abundance, and give the rock a semi-crystalline aspect. There are a few species of fossils in this bed, but they are difficult to extract. A little farther north, where a footpath leads up the cliff from 'Fox Holes ' towards Peak Hall, the following section may be seen : — Millepore Bed near Peak. Hard yellow sandstone Soft yellow calcareous sandstone, with fossils Hard ferruginous band, many small fossils ... Flaggy sandstone, speckled white Flaggy sandstone .. Dogger band, speckled white Soft white sandstone ; seems to contain a few casts of fossils Total The same beds cap the cliff at the gardens of Peak Hall ; and from this point the outcrop takes a direction inland at right angles to the cliff, until it meets the Peak Fault, when it is thrown up to the top of High Moor over the Peak Alum "Works. A thin bed of ferruginous sandstone, with a few indistinct casts of small fossils, may- be seen in 1 « The Yorkshire Oolites— Part I,' Proc, Geol. Assoc, vol. iii, p. 308. o 2 36 LOWER OOLITE. the gutter by the side of the highroad from Staintondale to Bay Town. Beyond this spot we have been unable to identify the Millepore Bed in the inland area. Some notes on the probable position of the Millepore Bed in the general scheme of, zonal classification of the Oolites will be found in Chap. V, p. 84. A full list of the fossils of the deposit is contained in the general memoir on ' The Jurassic Bocks of Britain : York- shire,' vol. i, pp. 209 and 210. Middle Estuarine Series. This series is separable from the Lower Estuarine beds only where the Millepore Bed is developed between them, i.e., in the district south of Bobin Hood's Bay, excellent sections being exposed along the cliffs from Blea Wyke southward to Cloughton Wyke. The renowned ' plant-bed' of Gristhorpe, south of Scarborough (Sheet 54), lies within this division ; and, mainly to the westward of the present district, the principal coal-seams of the Oolites also occur in it. In the area now described the series consists for the most part of shales, with three or four impersistent but well-marked bands of sandstone, often containing many plant remains. At Cloughton Wyke there is a very clear section beneath the Grey Limestone which just caps the cliff, and each band may be easily measured and examined as it rises from the shore. Section op the Middle Estuarine Sebies, Cloughton Wyke. ' Ft. In. Evenly -bedded massive sandstone, slightly oalcaredus, with a^few small fossils at the base.,. Soft rubbly stone with a band of dark shale at the top Hard dark shale Soft shale, ferruginous in parts ... Hard sandstone Soft sandy shale Thin band of wavy micaceous sandstone Shale... Sandstone with Equisetites at top Shalt Coal Dark sandy shale ... Sandstone with Equisetites Shaly sandstone with wavy lamination. Carbonaceous shale with irony doggers Sandy shale with vertical Equisetites ... Grey soapy shale with plant-remains ... Dark carbonaceous shale ... Grey soapy shale with plant-remains ... Coaly Seam Shale with thin hard sandy bands and soft jet Sandstone well-bedded, becomes shaly at base, also contain- ing nodules in another place ... Grey shale ... Seam op Coal and shale Dark grey shale, occasionally coaly and ferruginous Shale with coaly streaks ... Grey sandy shale ... Sandstone with carbonaceous markings Well-laminated shaly sandstone and sandy shale with ferru- ginous streaks ... ... ... ... ... 2 6 False-bedded sandstone with irony partings, fossiliferous in places, containing lenticular patches of rock similar to the Millepore Bed 13 11 2 15 1 2 10 1 4 1 4 6 9 9 3 6 1 2 6 10 6 4 6 2 5 10 1 3 7 2 6 7 2 3 Total 7 9 103 2 MIDDLE ESTITAEINE SEMES. 3f The sandstone at the top of this section is very hard and siliceous ; and in the neighbourhood of Harwood-dale, where it is quarried as a road-stone, the workmen give it the name of ' flint.' At Cloughton this bed contains at its base a few small fossils, apparently a species of Oryphaea, accompanied by Pleuromya sp. These and closely allied forms usually occur at the base, and often at the top, of the marine bands in the Lower Oolite, and seem to mark the gradual change from marine to freshwater conditions. On the strength of these fossils it may appear that the sandstone should be included in the Grey Lime- stone Series, into which it forms a passage, but we have found it more convenient to separate it from the distinctly marine series above. Besides the thin seams of coal which these beds contain, there is a good deal of carbonaceous matter scattered about, principally in the form of irregular streaks of coal and soft jet. This ' soft jet ' or ' Oolite jet ' was at one time extensively worked, being usually obtained by following in from the outcrop ; pits, however, were sunk where the jet occurred in sufficient quantity. The most extensive soft-jet mining was formerly carried on at Gate Holm Wood and High Normanby in the Hawsker district, and on a smaller scale at Cloughton Wyke, &c. The thin coal seams in the series have never been much wrought in the district described in this memoir. At Maybecks a level has been driven in the highest seam about 10 feet below the Grey Limestone Series ; and a seam is said to have been worked near Cloughton Wyke, but this may have been simply a ' soft-jet ' pit. At Blea Wyke the following section was measured in the series, but the total thickness may be about 15 feet more, as probably too much allowance was made for the slope of the cliff. An overlying sandstone, 15 feet thick, shown in a subsequent section (p. 39), is usually included with the series, but is excluded here as being so unmistakably marine that it pertains more naturally to the Grey Limestone Series. Middle Estuarine Series above" Blea Wyke. . Dark shale, coaly at base ... White rubbly false-bedded sandstone with shale partings .. Hard white sandstone with Equisetites .. . White shale with carbonaceous band at top Goal Seam Shale Sandstone, hard and white Millepore Bed at base. Total Lists of the fossil plants from the Estuarine beds, with notes on their mode of occurrence, will be found in Chap. VI. Grey Limestone Semes. This series is the thickest and most persistent of the marine bands intercalated with the Estuarine Oolites. It is fully developed throughout the area under description, and is traceable in almost the whole of the Yorkshire outcrop of the Lower Oolite. It has received various names 1 , but is most commonly known as the ' Grey Limestone' or as the 'Scarborough Limestone.' These terms are not, however, accurately descriptive, as the band consists of altera a- 1 See the ' Jurassic Bocks of Britain : Yorkshire,' vol. i. 1892, Item. Geol. Surv., p. 228. \i& LOWER OOLITE. tions of strata of different lithological character, which are not always grey and in which there is little that is really limestone ; the majority of the beds being calcareous shales and sandstones, and even in some places coarse grits. The general character of this series is very variable. To the south of Scarborough, where it is much thinner than in the present area, it' consists principally of calcareous shales with thin nodular ironstones and a little calcareous sandstone ; hut towards the north the sand- stones become more prominent, and over the interior moorlands develop into massive beds of coarse gritty rock. The ironstone, which occurs both in nodules and thin bands, is too poor to be of any commercial value, although it has been tried at one or two places in the interior. In most of the district now described the series is separable roughly into three parts of different lithological character. The upper portion consists mostly of shales containing ferruginous nodules, which become more calcareous lower down ; the middle portion, of sandy marl with thin calcareous sandstones which towards the west pass into hard calcareous coarse grits ; while the lowest part contains a varying thickness of impure limestone bands. North of Scarborough the Grey Limestone first appears above sea- level on the south-eastern side of Oloughton Wyke, where one of the finest and most accessible sections of the series occurs. Grey Limestone Series at Hundale Point, Cloughton Wyke. Ft. In. Upper Estuarine Sandstone. Ferruginous shale ... ... ... ... ... ... ... 60 Ferruginous bands with fossils in lower part ... ... ... 40 Shale with great numbers of fossils : Belemnites, Pteria braamburiensis (PhilL), Oervillia scarburgensis Paris, Pecten, Aslarte minima Phill., Modiola imbricata J. Sow., Pleu- romya scarburgensis W. & L. ... ... ... ... ... 27 Reef of grey shaly limestone with Pteria braamburiensis, Ostrea flabelloides Lam., Perna mytiloides Lam., var. quad- rata J. de C. Sow., Pentacrinus and Serpula... ... ... 4 Second reef of shaly limestone ... ... ... ... ... 2 Shale with Belemnites, Pteria braamburiensis, Pecten lens 3. Sow., Pinna cuneata Phill. ... ... ... ... ... 1 6 Third reef of shaly limestone 10 Shale with few fossils : Pteria munsteri (Goldf.), Cardium ... 2 Fourth reef, hard limestone 10 ( Sandstone with fucoids : fossils in upper part ... ... 3 6 Hard siliceous sandstone forming a sear which runs out to sea ... ... ... ... ... ... ... ... 2 6 Shale with fossils 1 0- / Ironstone ... ... ... ... ... ... ... 6 Siliceous sandstone with ripple-marks, in two bands ... 2 Shaly sandstone with wavy lamination 2 Sard shale ... ... ... ... ... ... ... 2 Coaly shale 4 Ironstone band ...» ... ... ... ... ... ... 14 Hard fossiliferous' grey shaly limestone: Oervillia scarbur- g ensis very abundant ... ... ... ... ... ... 4 Shale 2 Black shale 2 Sandstone forming Hundale Scar, 13 feet (see previous section, p. 36). Total of Grey Limestone Series 71 8 dEEY LIMESTONE SEMES. 3jf From Hundale Point northward, the Grey Limestone Series is exposed in the upper part of the cliff nearly as far a?i Hay burn Wyke. It then turns inland and runs westward to Gloughton Moor, where it is cut across by the prolongation of the eastern branch of the Peak Fault. To the eastward of this fault, north of Hayburn Wyke there is an outlying portion of the series, which is well seen in the Staintondale cliffs and in the neighbourhood of Blea Wyke. In the following section, measured in the cliffs above Blea Wyke Point, the series attains a greater thickness than in any other of the coast-exposures. It includes here some flaggy sandstone at the top, which apparently is not represented in the more southerly sections, but is recognisable in parts of the interior bordering Eskdale. GrEBT Limestone Series in the Clifps above Blea Wyre. Ft. Flaggy sandstone with Pleuromya in great numbers along the planes of bedding ; Pteria braamburiensis and a small Pecten abundant in the lower part ; Pholadomya occasionally found ... ... ... ... ... ... 15 Sandy shales, rather harder at top with small ironstone nodules containing Pteria braamburiensis, becoming soft and calcareous in the middle, and harder and more calcareous towards the base ; Belemnites somewhat plentiful... ... ... ... ... ... ... ... 55 Calcareous sandstone, weathering into blocks with a rounded outline, the outer face often covered with stalactite; many small fossils ... ... ... ... 5 Band of flaggy limestone, weathering readily; Pteria braamburiensis, Pecten lens, and Oervillia scarburgensis very abundant ... ... ... ... ... ... ... 2 Hard calcareous shales with nodules of close-grained lime- stone almost composed of shells ... ... 10 Band of flaggy limestone having the appearance of hard calcareous mud ... ... ... ... ... ... ... 2 Thin flaggy sandstone with Pleuromya along the bedding planes, passing gradually to a sandy shale ; casts of a small Pecten are very abundant near the base ... ... 15 Total 104 From the cliff-section at Blea Wyke the outcrop of these beds again runs inland in a westerly direction till it is cut once more by the Peak Fault. By this fault the beds are thrown up to the west, and their outcrop is carried back southward for over two miles, but is very obscure for some distance. At Pye Bigg, shales with Pteria braamburiensis are seen and can be traced with more or less certainty along the sides of Helwath Beck to its junction with Jugger Howe Beck below Dry Heads, where there is the following excellent section of the series. 40 LOWER OOLITE. Grey Limestone Sekies in Blood* Beck, Habwood-dale. Massive sandstone (Upper Estuarine) H.ard ferruginous sandy shale Hard ironstone band with Pieria braamburiensis Quartzose gritty band Grey sandy shale, getting harder at base Calcareous band full of Pteria braamburiensis Cherty band ... Shale Hard calcareous band Dark argillaceous shale with large Ostrea Quartzose gritty band crowded with Pteria braamburiensis, becoming sandy at bottom Ironstone band Shale with nodules and fossils of numerous species ... Hard calcareous band with fossils Hard limestone with well-marked joints, containing Gervillia scarburgensis Shaly limestone, more calcareous in parts Blue flinty bed Flaggy ripple-marked cherty bed Main flinty bed ... ... ... ... ... .... Cherty sandstone with fossils Ft. In. Total 46 7 Across Howedale Moor the outcrop of these beds can be well traced by thin flaggy bands of sandstone containing casts of a small Gryphaea ; and near Cook House, shales with Pteria braamburiensis are seen. The thin flaggy sandstones seem to be very persistent at the top of the Grey Limestone Series, and continue north and west at least as far as Kirk Moor Gate on Fylingdales Moor, where a section is visible in the beck on the north-western side of the Scarborough lioad, showing about 20 feet of thin flaggy sandstone resting on shaly sandstone and sandy shale, with ferruginous bands and nodules with Pteria braamburiensis and other fossils. These shaly beds are exposed to a thickness of about 1 1 feet, but the drift and debris covers the outcrop below, so that the calcareous beds are not well seen. Smaller exposures occur in a little stream 200 yards NE. of the last- mentioned section and in a small gully still farther to the north-east. Prom this point northward and westward across Fylingdales Moor the outcrop is rather uncertain owing to a thin covering of drift and to the apparent absence of the representative of the Moor Grit, which usually forms a guiding feature above the Grey Limestone Series. But the name " Graystone Hills " given to part of this area probably indicates the presence of the series, as the term is applied in several places where the grey flaggy limestone has been dug for liming the land. The sandstone quarried at Soulsgrave is, from its lithological character, probably the Moor Grit, from which we can infer the out- crop of the bed below; while in the fields on the northern' end of Ugglebarnby Moor small fragments of ironstone, with Pteria braam- buriensis, have weathered oat of the shale. Around the heads of the upper tributaries of Iburndale there are several exposures of the series. At New May Beck Plantation a small quarry has been opened in the hard calcareous bands. The upper of these is about 4 feet thick, and of a bright blue-grey Ft. In. 15 8 4 2 6 3 10 2 3 6 GEET LIMESTONE SERIES. 41 colour in the interior ; but the outer part soon loses its lime, and becomes a soft ferruginous sandstone, with a considerable number of casts of small fossils. The rock seems to decompose too readily to make a durable road-metal. The flaggy bed below is more sandy than at Peak ; but it still contains much lime and the usual fossils. A shallow well at the lodge at Newton House passed through the lowest bands of shaly limestone. Between New May Beck and Blea Hill Beck the outcrop is clear, and reveals the following section : — G-rey Limestone Series near New May Beck. , Shales with small doggers of ironstone and fossils' ... Band of hard blue calcareous and ferruginous sandstone ... Sandy shale, slightly calcareous Calcareous sandstone, with a band of grit in the middle, almost composed of casts of Pteria braamburiensis Calcareous sandy shale or impure flaggy limestone... Hard limestone band full of shells in a crystalline condition Hard calcareous shale Maggy sandy calcareous bed, harder in the centre ... Blue calcareous sandy band Calcareous sandstone, shaly in lower part, containing a few plant-remains and small fossils 7 The 10-inch limestone band is the only bed in the section that can fairly be called a limestone, the best of the other bands upon analysis yielding, according to information, only 34 per cent, of carbonate of lime. The top of the series is not exposed in the bank, but there is probably not more than 5 feet of shale hidden by the debris of the Moor Grit ; and in the bed of the stream farther south there is a flaggy sandstone with casts of Pleuromya in considerable numbers at the top of the shales. About 10 feet below the base of the series is a coal-seam, said to average 11 inches thick; its outcrop can be seen, and there is a drift into it exactly under the spot where the above section was measured. There are several other good exposures of these beds in the neigh- bourhood, the western branch of the May Beck stream presenting a section several hundred yards long. The principal fossils here are Pteria braamburiensis in great profusion, Qervillia scarburgensis, Pecten lens, a small Trigonia, Ostrea apparently two species, and many Belemnites ; but there is a remarkable paucity of species, except in the hard limestone band from which it is difficult to extract fossils. For a short distance along the left bank of the stream the outcrop is marked by small masses of calcareous tufa, in vrhich are some fine impressions of leaves of recent plants. To the westward, the next clear exposure is in Parsley Beck, where a good section of the lower hard calcareous beds may be seen. From this point the outcrop on Sleights Moor can only be fixed by its relation to the Moor Grit above, and by the small fragments of ferruginous sandstone or ironstone with Pteria braamburiensis that have been weathered out of the shales. South of Sleights Moor, close to the western edge of the map, there is a small exposure of the lower hard beds of sandy impure limestone in Little Beck ; but the rest of the series is completely obscured by fallen blocks of sandstone, &c, in the bed of the stream. At the 42 LOWER OOLITE. base of the Moor Grit is the flaggy sandstone, containing casts of Pleuromya in great numbers. In the adjacent Brocka Beck a nearly complete section can be seen, much resembling that at May Beck ; but the beds as a whole are less calcareous, and much of the argil- laceous matter is replaced by silica, so that the beds in the lower part of the series have become considerably harder, and not nearly so fossiliferous as they are to the east. In Eller Beck, near the Whitby road crossing, there is also a good section of the upper part of the series. The beds here seem to be rather more ferruginous, and a small trial adit was made close to the bridge, with the hope of working them for iron-ore, but they proved too poor for the purpose. Farther westward the beds are seen rising in the railway-cutting, and they then strike across the moor towards Killing Pits in the next map. A large outlier of the Grey Limestone Series, capped by the shales and sandstones of the Upper Estuarine Series, lies to the northward of the main outcrop and, crossing the Esk valley, extends to the westward of Whitby for two miles, the outlier being cut into two nearly equal parts by the Whitby Fault. Near the coast the most southerly section in the outlier is at a waterfall in Gate Holm Beck, just where the lane to Hawsker Bottoms crosses that stream ; the section is as follows : — Section in Grey Limestone Semes near Hawsker. Ft. In. Dark grey shale ... ... ... ... 2 6 Band of ironstone doggers with fossils ... ... ... 6 Dark shales... ... ... ... ... ... ... ... 2 6 Ironstone band, with Pteria hraambwriensis, Pecten, Gervillia scourburgensis, Astarts mmima, a large Trigonia, and other fossilB 10 Calcareous sandstone in cubical blocks containing many small fossils ... ... ... ... ... ... ... 5 Flaggy impure limestone containing a few species in great abundance ... Sandy calcareous shales .. . Hard dark calcareous shale with nodules of limestone almost composed of shells in a semi-crystalline condition Impure flaggy limestone very fossiliferous ... Dark shale with a few fossils Total The water makes a fall of about 15 feet over the last band of flaggy limestone, the beds beneath consisting of dark shales and thin sand- stones. This is a convenient section to examine, as the limestone beds were formerly quarried and burnt for lime, the flaggy bands being also used as paving-stone. Many blocks with Pecten, Pteria hraambwriensis, &c, may now be seen in the paved footway from Whitby to Kobin Hood's Bay. Farther northward the hard calcareous beds crop out in several places along the sides of the next small stream near Nype Howe ; but beyond this, till we reach Moorgate Lathes, the position of the series can only be inferred from that of the hard white Moor Grit above. Here the upper part of the hard calcareous bands and the shales over them may be seen. The Moor Grit crops out farther up the stream, the lower part of it being a flaggy sandstone. In the main branch of 05 § o a 20 6 4 3 3 3 1 6 5 1 10 4 2 GBEY LIMESTONE SEEIES. 43 Spittle Beck, at the waterfall not far from the Lodge, there is the following section : — Section in Spittle Beck. ^ . Ft. In. § ■'S < Close grained sandstone, evenly bedded and flaggy § ;£ J at base /Softer flaggy sandstone, with casts of Pleuromya ... Band of ironstone nodules, small specimeas of Pteria braamburiensis ... Soft sandstone, splitting to very thin layers ... Ferruginous sandy shale, slightly calcareous in lower part, with calcareous nodular band at base Shaly limestone or marl, a mass of shells, Pteria braamburiensis, Oervillia scarburgensis, Pecten, &c. Hard blue siliceous limestone Calcareous shale ... Shaly limestone or marl Hard sandy calcareous shale ... \ Impure limestone band ... Below this are dark shales with several trial-holes for soft jet, all of which appear to have heen unsuccessful. The shaly limestone bands are of the nature of a fossiliferous mudstone with great numbers of Pteria, and when first exposed' are very hard and difficult to break, but rapidly disintegrate from loss of lime, and can then be broken to pieces with the fingers. West of this point the outcrop, hidden by drift, soon comes against the Whitby Fault, by which the series is thrown down to the west, reappearing in the banks of the Esk. It was probably exposed at the borehole put down in Larpool Wood, opposite the Gas Works, but no record of the section appears to have been kept. A little farther south, under the chalybeate spring, the sides and bottom of a small excavation yielded ironstone nodules with Pteria hraamburiensis. In the side-valley at Cock Mill, in Larpool Wood, the waterfall passes over the Moor Grit, and cuts into the soft shales of the Grey Limestone below. Half, a mile farther to the south-west there is an interesting series of sections in the stream descending from Sneaton (named on the six-inch map Shawm Bigg Beck) and in its tributaries. Although the entire series may be seen three or four times, the vegetation is too dense for an accurate section to be measured, but the following is an approximate summary : — Grey Limestone Seeies north op Sneaton. Ft. In. Light-coloured sandy shales with thin bands of sandstone, containing a few casts of fossils ; at the base is a row of ferruginous nodules crowded with Pteria braamburiensis 10 Hard calcareous sandstone with bright blue-grey fracture ; top often covered with fragments of encrinites ... ... 40 Flaggy siliceous limestone-band; Oervillia scarburgensis abundant; also Pecten... ... ... ... 16 Calcareous shale, about ... ... . . ... ... ... 50 Very hard calcareous beds, lower part having a conchoidal fracture '20 The outcrop to the south of this has to be inferred, as the flagstone quarries in the Moor Grit in and around Sneaton are the only evidence for its position. 44 LOWER OOLITE. North of the Esk there are a few sections which show the position of the Grey Limestone Series ; the principal of these is in the bank opposite the iron -foundry between Whitby and Ruswarp, where shales with small fossils can be seen ; the sandstone above, which is exposed in the railway-cutting, is evidently the Moor Grit. About a quarter of a mile 'north-west of Ruswarp, in a small stream running east and west, there is for some 200 yards a con- tinuous section of the shale and upper part of the calcareous beds, the latter containing a large Ostrea in abundance. A very small section of siliceous calcareous rock is also seen in the small stream below Sneaton. The Grey Limestone of the Yorkshire area was for a long time con- sidered the equivalent of the Great Oolite of the South of England ; but, if thejist of fossils from it be compared with the fossil-list from the Great 'Oolite of the southern counties, the difference is at once apparent. In fact, if we exclude those forms which have a wider range, there are very few species common to the two. The correlation of the series in the light of modern palasontological research is discussed in Chap. V, p. 84. Full lists of its fossils will be found in the general memoir on ' Jurassic Rocks of Britain : Yorkshire,' vol i, pp. 249-51, and vol. ii (' Tables of Fossils ') ; also in the memoir on the ' Geology of the Oolitic and Cretaceous Rocks south of Scarborough,' 2nd ed., 1904, pp. 15-16. Upper Estuarine Series. From the persistence of the Grey Limestone below it, and of the Cornbrash above, the Upper Estuarine Series is the most clearly defined subdivision of the Estuarine deposits of the district. It has a thickness of about 200 feet and is separable into two portions, the upper and thicker consisting principally of shale or shaly clay, and the lower, of sandstone. This sandstone, known as the Moor Grit, is distinguished by a separate colour on the map. The outcrop of the series occupies a larger area than that of any other subdivision of the Jurassic rocks in the district. It extends in a broad belt from the coast north of Scarborough across the high central moorlands up to the western boundary of the map. Except where partly covered by drift in the neighbourhood of the coast, it forms a wet and sterile soil, almost wholly uncultivated. The Upper Estuarine Series is' the most barren in fossils of all the Lower Oolites. The remains of a few plants have been found in sand- stones at Scalby Ness Point ; and in the cliffs south of Scarborough (in Sheet 54) the impressions of a fresh-water bivalve shell, referred to Unio or Anodon 1 , have been observed in similar sandstones, indicating fresh-water conditions at this place. Recently, also, within the present area, on the coast near Burniston Fields, about half-mile south of Long Nab, the casts of reptilian foot-prints have been dis- covered, at first in loose blocks on the shore and afterwards on the under-surface of a band of sandstone among shales in the cliff. 2 But 1 See ' Oolitic and Cretaceous Rocks South of Scarborough,' Mem. Geol. Surv., 2nd edit., 1904, p. 19. J. A. Hargreaves, ' Fossil Footprints near Scarborough,' Naturalist, for 1913, pp. 92-6 ; and ibid, for 1914, pp. 154-6. TJFFEB estuarine sebies. 45 there appears to be in this series an absence of rich plant-beds such as occur in the Middle and Lower series, and it is suggested that the conditions had become less favourable to the development of organisms or, at least, to the preservation of their remains. On the south, the series is exposed in the cliffs immediately north of Scarborough, at the southern margin of the map, and continues northward along the foreshore, much hidden by beach-material, past Scalby to Long Nab, over three miles north of Scarborough, but is frequently concealed in the cliffs by the thick covering of drift. The strongly false-bedded character of the sandstones is strikingly dis- played in the reefs on this shore. Occasionally, a band of granular ironstone makes its appearance in the series, of which there is an example at Scalby Ness Point, also seen at intervals along the Burniston Cliffs. Before Cloughton Wyke is reached, the Upper Estuarine Series leaves the cliff and passes inland along the foot of the Hackness Hills, and thence across Harwood-dale Moor, Fylingdales Moor, Sneaton High Moor and Sleights Moor, to Goathland ; forming a broad tract of cold desolate moorland.' The Moor Grit varies rapidly in character and thickness, being made-up of a succession of wedges or lenticles without persistent bedding. In the Whitby district it is a hard white siliceous rock, worked for different purposes according to its local composition. Good exposures occur in and about the cliffs of Cloughton and Staintondale, where it is often a massive rock and has been rather extensively quarried. It forms a well-marked feature arching round the rising ground near Kobin Hood's Bay, though there are few openings in it. To the north of the Bay it has been extensively quarried at Sneaton, for flagstones ; and nearer Whitby it is exposed at Beacon Hill and Moorgate Lathes and around Larpool Woods. A good section of the sandstone was afforded by the railway-cutting close to Whitby. The argillaceous part of the series, overlying the Moor Grit, may be more correctly described as hardened clays rather than as shales. The clay as a rule is more or less plastic ; contains very little calcarepus material ; weathers into small prismatic fragments ; and is generally of a whitish colour, though sometimes mottled or red. Some of the beds are suitable for making good bricks and have been so used in other areas. Associated with these clays are numerous irregular lenticles of sandstone and sandy shale, and also some thin bands of hard close- grained sandstone, often used for walling and moor-enclosures. There is some doubt as to the exact classification of the Upper Estuarine Series in relation to the marine Oolitic sequence of the south of England. The Grey Limestone underlying it is known to belong to the Inferior Oolite, while the Cornbrash above it comes above the Great Oolite ; hence the question arises whether the inter- posed non-marine series, containing in itself no direct indication as to age, should be classed as Great Oolite, or combined with the underlying strata as part of the Inferior Oolite. On the whole it appears to range best with the underlying series ; and this method is adopted in the table in Chap. I, p. 6, as was done in the previous 46 LOWER OOLITE. edition. In notes on the subject expressed in Chap. V, p. 85, how- ever, it is suggested that the Moor Grit may represent the upper part of the Inferior Oolite, and that the remainder of the Upper Estuarines- should be correlated with the Fullers' Earth, which belongs to the Great Oolite Series. COBNBBASH. The term ' Cornbrash,' applied by William Smith to the highest division of the Lower Oolites, is the old agricultural name given to the thin band of rough shelly rock, which in the southern counties breaks up into a loose rubble or ' brash,' forming good land for grain-growing. The name is however rather inappropriate in the Yorkshire district ; as, owing to the thick sandstones which occur at a short distance above, this bed only crops out in the steep cliffs or escarpments formed by these more massive sandstones ; and con- sequently, being exposed ODiy over an insignificant breadth, is of no importance from an agricultural point of view. The most distinctive part of the Cornbrash consists of a thin band of hard ferruginous limestone crowded with fossils, which becomes softer and more earthy below, and passes down into calcareous shales with but few fossils. These beds, combined, are not more than from 1 to 2 feet thick where first exposed on the shore south of Scarborough ; but to the northward and inland they are thicker and more compact, increasing to as much as 7 or 8 feet in Newtondale (in Sheet 43) just beyond the western margin of the present map. Resting on this thin band of rock are from 6 to 8 feet of dark shales containing a few fossils ; these, the so-called ' Clays of the Cornbrash,' are very similar in lithological character to the lower part of the Oxford Clay, and no doubt foreshadow the physical conditions of that deposit. They pass up into more sandy shales which appear to be nearly destitute of fossils, and finally blend with the shaly base of the Kellaways Rock, so that no very exact line can be drawn between the two. A reddish - band of rotten ferruginous shale generally marks the junction of the ' Clays ' with the limestone band, probably caused by the percolation of water along this line. The main outcrop of the Cornbrash is confined to the southern portion of Sheet 44, and has an extremely sinuous course, following the deep indentations of the dissected moorland plateau. Small outliers occur to the north of the main outcrop, on the ridges between the streams forming the head-waters of the Derwent west of Harwood- dale, and on the water-parting between the Esk and the Derwent at Blea Hill Rigg. The formation does not touch the coast in this area unless at the very margin, in the. North Cliff at Scarborough, where, in the map to the south (Sheet 54), it has been obscurely seen at times in the slipping ground and has shed fossiliferous blocks to the beach from which good collections have been made. Owing to the outcrop of the Cornbrash occurring among shales, and the bed itself being thin, it is seldom well exposed inland. Along an outcrop extending westward between 30 and 40 miles there are scarcely half a dozen good exposures of the rock. The best sections are obtained where the overlying Kellaways Rock has weathered out into a vertical cliff, as in Lang Dale and Newton Dale ; at other places the Cornbrash is usually covered by debris and soil. The outcrop is, CORNBEASH. 47 however, well marked along the flanks of the Tabular Hills by the line of wet ground at the base of the conspicuous feature formed by the Kellaways Rock. From the south of Hackness northward and westward, the Corn- brash continues along both sides of the Derwent valley and those of the branch-streams coming down from Troutsdale, Bickley, and Crosscliff ; also skirting the sides of the beautiful Langdale gorge. In the banks of the stream below Low Langdale End the rock is well exposed, and the following section was there measured : — Ft. In. Hard ferruginous limestone with fossils ... ... ... 2 Shaly sandstone ... ... ... ... ... ... ... 1 Sandstone with root-like markings 4 Farther north the fossiliferous portion appears to be rather thicker ; and in the upper part of Lang Dale, where this bed is seen in several places, the measurements are : — Ft. In. Hard limestone with Osirea flabelloides ... ... ... 3 Shaly bed ... 1 Sandstone with markings ... ... ... ... ... 2 6 A.t the head of Lang Dale the outcrops on the opposite sides diverge sharply ; that on one side turns to the east, and, striking along the hillside above Harwood-dale and Scalby, completes the circuit of the Hackness Hill ; while that on the other side, turning west, follows the right bank of the Derwent to its head, attaining at High Woof Howe an elevation of over 900 feet, and thence falls gradually towards Fen Steps into Newton Dale. In this fine dale, just beyond the western edge of the map, the Cornbrash has increased in thickness to 12 feet or more. Here it attains greater importance and is better exposed than in any other part of Yorkshire, being well seen in the mural precipices bordering the valley. The Cornbrash has yielded a rich fossil-fauna in which species of brachiopoda, lamellibranchiata and gasteropoda are particularly numerous, along with some cephalopoda, echinodermata, Crustacea, &o. Full lists will be found in the previously-cited general memoir on the Jurassic Rocks, pp. 264-6, and in the memoir, also cited, on the Sheet to south of the present area, pp. 23-4. The fossils appear to indicate that the Cornbrash of Yorkshire represents only the upper portion of the formation included under this name in the more southerly parts of England, as is further explained in Chap. V (p. 85). 48 CHAPTEE IV. MIDDLE OOLITE. Practically the whole of the Middle Oolite sequence is represented in the area falling within the southern part of Sheet 44, though the higher members are confined to small outliers from the main outcrop in the map to the south. The classification of the component strata has been somewhat modified since the first edition of this memoir was published, and now stands as shown in the table in Chap. I. p. 6, this being the arrangement adopted in the later memoirs on the Jurassic Bocks of Yorkshire. 1 The different members of this variable sequence generally pass into each other vertically by insensible gradation, and often show similar passage laterally also ; but they fall naturally into two main groups ; the lower containing the Kellaways Eock and Oxford Clay ; and the upper, here termed the ' Corallian ' series, containing the Lower Calcareous Grit, Passage Beds, Lower Coralline Limestone, Middle Calc. Grit, Upper Limestone and Upper Calc. Grit. Most of the beds are richly fossiliferous and have been divided into palaBontological zones, based principally on their ammonites. Authorities have differed as to the best method of zonal division ; and there is still much investigation required before a final result can be expected. The strata grouped together under the term ' Corallian ' in this district are a thick series of calcareous sandstones and limestones with occasional thin shaly partings. This series, interposed between the Oxford Clay and the Kimmeridge Clay, is in North-east Yorkshire of great stratigraphical importance, forming some of the boldest and most characteristic physical features of the country. But when traced southward the whole series disappears before the Humber is reached, and is apparently replaced by clay, so that the Oxford Clay and the Kimmeridge Clay are conterminous and difficult to separate except by their fossil contents ; and this condition persists through the greater part of the outcrop in the East Midland counties. Thus, the Yorkshire Corallian may have its equivalent in another region partly in the Oxford Clay and partly in the Kimmeridge Clay ; and it is recognised, from the fossils, that the series may be divided into two portions for the purposes of correlation. The division is made at the top of the ' Lower Limestone '; the beds below this line have Oxfordian affinities, and were formerly classed as the ' Zone of Amm. perarmatus'; while the beds above, with Kimmeridgian affinities, were classed as the 'Zone of Amm. plicatilis.' This method of zoning has, however, been replaced by the newer classification stated in a later chapter (p. 60). 1 ' The Jurassic Rocks of Britain : Yorkshire,' vol. i, 1892, Chap, xii ; and ' Oolitic and Cretaceous Rocks south of Scarborough,' 2nd ed., 1904, p. 3. KELLAWAYS BOCK. 49 There has been some variation in the application of the term ' Corallian ' by previous authors 1 ; in this memoir it is used for the whole series between the Oxford Clay and Kimmeridge Clay, while ' Coralline Oolite ' is applied to the ' Lower ' and ' Upper ' limestones with the intervening ' Middle ' grit. Some of the lower members of the Middle Oolite are well exposed in the cliffs north of Scarborough Castle, which fall just within the map; but this is the only place at which the outcrop touches the coast in the area under description. Inland, it forms the ' Tabular Hills ' and the picturesque country around them. Kbllawats Rook. The Kellaways Rock, so named from a locality in Wiltshire, is generally a soft thick-bedded sandstone of a brownish-yellow colour ; on the coast, and occasionally inland, the upper part is very ferruginous," and forms a hard compact bed of a deep red colour crowded with fossils ; below this- are softer sandstones or mudstones with but few fossils, which gradually pass into sandy shale, and finally into the bluish shale of the Cornbrash clays. In the inland exposures the rock is usually a porous friable sandstone, but its lithological character varies much both in different localities and" in the different bands which make up its mass. Where the rock first rises from the sea at Newbiggin Wyke, five miles SE. of Scarborough, it is only about 12 feet thick ; but its thick- ness increases rapidly northward, so that in the exposure at the North Cliff, Scarborough, just outside the southern margin of the present map, it has attained 76 feet. This section is recorded by Hudleston, 2 as follows : — Kellaways Rock at North Cliff, Scarborough. Ft. in. Brash and broken rock, very ferruginous, containing Belemnites Owenii, Ostrea flabelloides, Chyphsea dilataia, Ornatus ammonites, &c. ... ... ... ... ... 4 Upper (■ Subcrystalline fossiliferous rock with ") Tier of I many specimens of ammonites, &c. ... 1 [ ,„ , Solid \ Rotten irony sandstone with similar fossils 1 6 I Stone. [Building stone, poor in fossils ... ... 7 6 J Loose Muddy Sandstones (thickness estimated) ... ... 20 Lower Tier of Solid Stone, with Belemnites Owenii, &c. .,, 12 Loose Clayey Sandstones containing hard bands and doggers with Astarte like A. carinata, Phil., Trigonia Rupellensis, Modiola cuneata, Avicula braamburiensis, Pholadomya Mv/rchisoni, &c. ... ... ... .. ... 30 76 The rock is faulted down at the eastern end of this section, so that, below the Castle, it is seen on the shore at both the north and south angles of the Castle hill, the upper beds being very conveniently situated for examination. 3 The rock where exposed to the force of the sea is hard, and forms a strong natural protection to the soft shale above. The upper surface of the scar is a hard ferruginous oolite ; above 1 For details see ' Jurassic Rooks of Britain : Yorkshire', vol. i, p. 300. 2 ' The Yorkshire Oolites, Part II.' Proe. Geol. Assoc, vol. iv, 1876, p. 364. 8 Perhaps not now so clear ; see footnote, p. 51. 50 MIDDLE OOLITE. this is a thin greyish limestone with a few oolitic grains, containing Belemnites oweni, &c. Turning inland at Scarborough the outcrop of the Kellaways Rock makes a conspicuous and easily recognisable feature along the northern and western flanks of the Tabular Hills. This feature, although fairly continuous, breaks up into a series of small ' nabs ' or rounded hills which are very characteristic of the outcrop. This seems to be due to the strong jointing of the rock, together with its tendency to run in calcareo-siliceous masses, which weather out into isolated projections along the inland escarpment. It is probably the local absence of these harder masses, and the tendency of the rock then to become soft unconsolidated sand, that occasionally causes the feature to be nearly lost and the outcrop difficult to trace. Along the outcrop to the west of Scarborough there is no section where the whole bed can be measured or studied in detail. The rock has been quarried largely at Hackness, where it supplies a good building- stone if the blocks are carefully selected. Professor Phillips sayp, ' Its durability is evinced by the condition of the stone in the ancient church at Hackness, which was probably built about the end of the thirteenth century ; and its good effect in architecture may be seen to great advantage in the new church and new museum at Scarborough, and especially in the museum of the Yorkshire Philosophical Society [at York], in the construction of which blocks of great magnitude have been employed.' In the Hackness Hill the rock forms a complete outlier, around which its outcrop may be easily followed, as well as along the bottom of the interior valleys. The best section is on the western side, in the gorge formed by the river Derwent at Lang Dale. Here the main mass of the rock forms a craggy cliff on either side of the valley, overhanging the soft Lower Oolite clays below. In this district the Kellaways Rock is thicker than at Scarborough, as there appears to be over 100 feet of sandy rock altogether. The increase of thickness is, however, chiefly owing to the base of the Oxford Clay becoming more sandy and passing into rock, so that there is not much change in the combined thickness of the two formations. Along the northern part of the outcrop the expansion of the upper portion of the Kellaways Rock at the expense of the Oxford Clay is particularly well marked ; and on Blakey Moor and near the higher part of Lang Dale the sandstone in this upper portion forma a distinct feature above the general spread of the rock on Lockton, Allorston, and Wykeham High Moors. This upper sandstone appears to be separated from the main mass of rock below by a thin band of clay, which seems to die out towards the south. In this area the top sandstone and the intervening band of clay are shown separately on the map ; but the boundaries are obscure, and it is probable that there is a gradual passage from one into the other, as is the case in most of the subdivisions of the Middle Oolites. The central portion of the Kellaways Rock in the same district is a massive sandstone, graduating into clay or shale both towards the top and towards the base. It is this more massive portion which forms the large spread of moorland to the west of Langdale Rigg. The rock is here very coarse ; and the surface of the moor, covered with its large blocks, has very much the aspect of a Millstone Grit country. OXFORD CLAY. 51 At High Woof Howe the outcrop reaches over 950 feet above O.D., its greatest elevation. There are small outliers of the rock north of the main outcrop, at Blea Hill Rigg and on the moorlands to the southward ; while an inlier is exposed in Staindale, and portions of another at the Hole of Horcum in the south-western part of the map. The Kellaways Rock has yielded an extensive marine fauna especially rich in ammonite species, and in lamellibranchs of which the Trigoniae are of particular interest ; gasteropoda are fairly well represented, though not numerous ; echinodermata and brachiopoda are relatively scarce, with the exception of Rhynchonella socialis Phill., which occurs in profusion. The principal collections have been made from Scarborough and Hackness ; fossils occur most plentifully in the upper part of the rock. Full lists of the fossils will be found in the memoirs previously cited ; 1 and some notes on the ammonites and on the zonal classification are given in Chap. V, p. 86. Oxford Clay. Lithologically, the Oxford Clay is in general a grey sandy shale nearly uniform throughout, which towards the top becomes more sandy, and passes by insensible gradations into the Calcareous Grit above, the boundary adopted on the map being drawn at the level where many springs ooze out at the surface. At the base the junction with the Kellaways Rock is, on the coast, moderately sharp ; but inland, especially towards the north, it is, as mentioned under the last heading, ill-defined, the lower beds becoming more sandy and ap- parently being in part replaced by sandstone which lithologically may be considered as part of the Kellaways Rock. This inter- changeability of type is further discussed in Chap. V, p. 86. There is a great paucity of organic remains throughout the greater part of the Oxford Clay of Yorkshire. Most of the fossils which have been obtained from it bave been found in the lower part, in fact only a few feet over the Kellaways Rock ; but the reputed almost un- fossiliferous character of the remainder may in a measure arise from the sparsity of accessible exposures. One of the best places for collecting is the marly clay just above the Kellaways Rock at the base of the Scarborough Castle Hill. 2 The formation represents the sedi- ment of a sea of moderate depth and wide extent. » At Scarborough the Oxford Clay is well exposed in the steep cliffs of the Castle Hill, this being the most northerly point that it attains on the coast. Its thickness here is about 120 feet, but at the south angle of the hill part of it appears to have been squeezed out in a curious manner ; for while the Kellaways Rock is bent up at a rather high angle by the fault which crosses the neck of the promontory, the Calcareous Grit is but little affected, and consequently the thickness of the intervening Clay decreases rapidly as it approaches the fault. The outcrop of the Oxford Clay inland is easy to distinguish by the slope of wet clayey soil it forms between the steeper banks of the Calcareous Grit and Kellaways Rock. It continues along the face of 1 ' Jurassic Rocks, &c, Yorkshire,' vol. i, pp. 276-8 ; and ' Oolitic etc. Rocks south of Scarbro',' pp. 30-1. 2 Since this was written, the section has been much obscured by the construction of the ' Marine Drive ' under the cliffs. D 2 52 MIDDLE OOLITE. the great escarpment of the Tabular range from Scarborough west- wards, cropping out at the base of the Calcareous Grit feature along the banks of the Derwent and its tributaries between Hackness and Saltergate, and along the sides of the outliers of Hackness Hill, Langdale Rigg and Blakey Topping. There are also inlying portions, of small extent, in Staindale and the Hole of Horcum. It is seldom, however, tbat the clay is well exposed or that there are any sections of interest. The clay was formerly dug at Coomboots, near Scalby, for brick and tile making ; but it was found that the Cornbrash clay which crops out lower down the slope afforded a better material. There has been much discussion respecting the zonal classification of tbe Oxford Clay in respect to the ammonite-fauna, this question being complicated by the changes of lithological composition which the upper and lower portions of formation undergo in different parts of England. The classification presented by Mr. Buck'man in Chap. V (Table I, p. 60) represents the more recent view. The fossils include many ammonites and lamellibranchs, with a few gasteropods, brachiopods, crustaceans and annelids. Lists will be found in the memoirs previously cited ('Jurassic Rocks,' vol. i, pp. 294-5; and ' Scarborough," pp. 30-1) . Lower Calcareous Grit. In lithological character the Lower Calcareous Grit is a yellow calcareous sandstone with doggers and cherty bands, passing down into softer sandstone which becomes more shaly towards the base and gradually passes into the sandy shale of the Oxford Clay. Although the term ' Grit ' is applied to the rock, there is very little of it that would be correctly classed as ' grit ' ; in fact, even many of the sand- stones of the Lower Oolite are harder, firmer and more gritty than this, bed. The upper part of the formation is generally marked by the pre- sence of 10 to 18 feet of soft, sandy beds containing lines of calcareo- siliceous nodules or doggerB which weather out conspicuously in the cliff-sections, and may be observed also at many places inland. These rest on a band of very hard siliceous rock about 3 feet thick, which from its angular mode of weathering forms a sharp projection in tbe cliffs. In the interior this band of rock forms the summits of the Tabular escarpment, where, from the softer sands above being easily denuded away, it covers a large part of the surface, giving rise to the plateaus or table-lands which are so characteristic of these hills. Below this comes the main mass of the Lower Calcareous Grit, com- posed of rough reddish-yellow grits with siliceous bands and nodules along certain lines. Becoming more argillaceous towards* the base, these beds pass by insensible gradations into the Oxford Clay below ; their upper portion weathers into a very rough and irregular surface from the unequal hardness of the sandstone. In tbe faulted outlier at Scarborough the Lower Calcareous Grit has a thickness of about 60 feet, and is well-displayed in the cliff- section on the north side of the Castle Hill, the ' ball-beds ' and most of tbe other beds'being easily accessible. The following section at this place shows the succession of the lower Corallian strata above the Oxford Clay. LOWER CALCAREOUS GRIT. 53 Section in Corallian Rocjks on the north side op Castle Hill, Scarborough. 1 Ft. In. Boulder Clay. Lower Lime- f Oolitic Limestone in several beds, with Echino- Passage Beds. 6- <5 Is o i— i I* \ Lower Cal- careous Grit. ibrissus scutatus Lam., Exogyra nana J. de C. Sow., Gervillia aviculoides J. Sow., and Trigonia Palse-bedded grit with small projections weathering black ... Soft sandy stone with ferruginous nodules Parting with Pectm subfibrosus D'Orb. ... Irregular spongy grit with Gylindrites ... Soft bed with uneven base ... Pine-grained grey spongy grit with GerviUia aviculoides ... Pine-grained hard grey grit with Gervillia aviculoides and Gryphsea dilatata J. Sow. ^Yellow sandy grit Yellow grit White grit passing down into massive spongy grit with GervilUa, Ostrea, Pecten Yellow grit with Gervillia ... Hard band of grit ... Shaly band with Pecten subfibrosus, Exogyra nana Solid bed of grit Six or seven courses of sandy yellow spongy rock with Rhynchonella, Pecten subfibrosus, Trigonia, Ammonites ' cordatus ' ^Yellow sandy grit 'Bright-yellow soft sands with siliceous balls ... Hard massive grit, evenly jointed, with a spongy line on top ... Massive sandstone passing down into shaly sand- stone, and sandy shale ... *... On Oxford clav. 26 6 4 1 6 8 1 6 2 3 1 6 3 5 2 1 1 2 7 2 6 18 3 38 Inland, west of Scalby, the Lower Calcareous Grit crops out in a range of bold escarpments, generally facing the north, but also flank- ing the course of the dales in the neighbourhood of Hackness, Trouts- dale and Langdale End ; and stretching thence away to the west in the magnificent sweep of Cross Cliff. At Hackness the strata are deeply cut into by the Derwent, which has severed the outlier of Lower Calcareous Grit forming the hills to the north and east of this place from the main outcrop ; the river and its tributaries have produced numerous deep ramifying valleys, the sides of which are frequently wooded. Between these picturesque valleys the Calcareous Grit terminates in a series of bold spurs or ' nabs ' of striking aspect, bearing a resemblance to natural fortresses ; in fact, from the remains of dykes and other anoient works which are scattered over their summits, there is very little doubt that they were used as strongholds in former times. Separated from the Hackness outlier by the Langdale gorge of the Derwent is the remarkable minor outlier of Langdale Rigg which, though nearly two miles in length, is often not more than 50 yards broad at the top. This narrow tabular ridge rises to a height of 800 feet at its northern extremity, and when viewed endwise from the north side has exactly the appearance of a sharp truncated cone. The 1 The full section down to the Cornbrash is published in ' Vertical Sections,' Geol. Surv., Sheet 67, No. 4. 54 MIDDLE OOLITE. curious conical hills of Howden Hill (Low Langdale End) and Blakey Topping also have their summits capped by this rock. Farther west the escarpment of the Lower Calcareous Grit runs out to the north in a long promontory, and forms a large spread of moorland rising near Saltergate to a height of 950 feet above sea-level, its greatest elevation in the area. Throughout this region the Lower Calcareous Grit has a thickness of about 140 feet, and consists principally of yellow calcareous sand- stone graduating into shale in the lower part, so that no exact line can be drawn between its base and the top of the Oxford Clay. In the upper part the rock becomes very sandy and contains lines of nodules similar to those seen on the coast. The fossils of the Lower Calcareous Grit include numerous ammo- nites and other cephalopods, gasteropods and lamellibranchs, along with some sponges, corals, echinoderms, annelids, &c. They are often particularly abundant in the concretionary doggers. Pull lists will be found in the memoirs previously cited (' Jurassic Bocks,' vol.i, pp. 302-3, and ' Scarbro',' p. 40). The minute siliceous sponge, Rhaxella perforata Hinde, is so abundant in some beds as to imply that it has played an important part in the production of the rock. Passage Beds ob Greystone.. These beds were formerly included in the upper part of the Lower Calcareous Grit of the coast-section, while inland the higher portion of them was classed with the Lower Limestone. They in reality form a passage from the. sandy beds of the Calcareous Grit into the Limestone above, but they have such a separate lithological character, and in the country west of Forge Valley (in Sheet 54} make such a distinct physical feature, that they have been mapped as a separate division. In this district, which extends into the south-western part of the present map, they are locally known by the name of ' Greystone,' and were described under this name in the previous edition of the present memoir ; but the term ' Passage Beds,' introduced by Hudleston, is now more generally adopted. They are extensively quarried for building walls and mending roads, both in the main outcrop and in the Hackness outlier to the north-east, where they are better known by the name-' Wallstone.' Their thickness in the Castle Cliff at Scarborough is 37 feet, but diminishes to about 25 feet around Hackness. In lithological character these beds present every gradation from a sandstone to a limestone ; most of the rock, however, consists of highly siliceous limestone, which along certain horizons is very fossiliferous. Inland the beds are more fissile than they are on the coast, and split up .into flags, often of considerable dimensions. They pass down into a loose sand containing decomposed fragments of rock, which is evidently a residual condition after the lime has been dissolved out ; on some of the more exposed localities on the moors there is nothing left but the sand, while the springs which issue from them form large deposits of calcareous tufa in the valley below. The upper part of the rock becomes more calcareous and oolitic as it approaches the true limestone above, the passage being so gradual that no exact line can be drawn between them. CORALLIAN BEDS. 55 The Passage Beds are best exposed in the faulted outlier of Scar- borough Castle Hill. Details of the strata at this place have been given in the preceding section (p. 53) which illustrates their diverse composition and fossiliferous character. On the Hackness outlier tha. Passage Beds consist of a hard ' glance ' limestone, rather ferruginous in places and very fossiliferous, and capable of being split into slabs. The lower part of the rock graduates into soft sands, and these again into the more solid sand- stone of the Lower Calcareous Grit below. Farther to the west, beyond Bickley, the rock becomes much more gritty, and, losing the calcareous aspect almost entirely, passes into nearly a true grit, with here and there a few lenticular aggregations of fossils and calcareous bands. It is this rock which forms the remarkable blocks known as Bride Stones, which stand up so weirdly on the bleak surface of the moor above Staindale. Besides several masses which jut out of the side of the hill with the aspect of ordinary crags, there are not less than ten blocks that are detached, one measuring as much as 80 feet in circumference and 16 feet in height. About half a mile farther west the rock has the appearance of having been run together and cemented by silica into a hard mass. It is evidently this siliceous induration which has enabled the Bride Stones to stand out against the effects of the weather. Along the dales to the south this same hard gritty character is very noticeable, and often causes incipient lines of crags to jut out along the sides of the valleys. At Lockton the beds again become more calcareous, and pass into a hard blue rock which is full of fossils ; but the character is variable, and the calcareous matter is readily dissolved out, so that in neigh- bouring places all that is left of the calcareous beds are some thin lenticular patches or nodules embedded in sand. The fossils of the Passage Beds have been carefully studied by Blake and Hudleston, whose accounts have been largely reproduced in the Survey memoirs previously cited (' Jurassic Bocks,' vol. i, pp. 319-20 ; ' Scarbro',' p. 48). The zonal position of the beds is indicated in a later chapter (p. 60). Coralline Oolite (Lower Limestone, Middle Calcareous Grit and Upper Limestone) and Upper Calcareous Grit. The remaining members of the Middle Oolite occupy a relatively small area on the map and may be conveniently described together. Only the lowest member touches the coast at Scarborough ; and, of the main outcrop, the much-dissected northern margin alone crosses the southern margin of the map in the western quarter, while in the Middle Oolite of the great Hackness outlier, these upper beds are reduced to a belt of isolated patches or minor outliers. At one place only, namely, on the hill south of Silpho, is the uppermost member represented. As already noted, the Lower Limestone is more closely allied by its fossils with the underlying series than with the beds above it ; and there is a marked difference between its fauna and that of the Upper Limestone. But stratigraphically the beds form a continuous sequence ; and, in places beyond the present area, where the Middle 56 MIDDLE OOLITE. Calcareous Grit is not developed, the Upper and Lower Limestones combine into a stratigraphical unit. The following generalized section of the succession in the Hackness outlier, down to and including the Passage Beds, will show the mam characters of the subdivisions and their average thickness in this neighbourhood : — Upper Calcareous Grit. Generalized Section or Corallian rocks near Hackness. Soft reddish sandstone, not seen in section ; about Ft. 10 Upper Limestone Middle Calcareous Grit Lower Limestone Passage Beds 'Coral rag w^th Thamnastraea eoncinna (Goldf.) and borings of Lithodomi. Massive oolitic limestone in several beds, very fossiliferous, with Astarte, Pseudo- melania h-eddingtonensis (J. Sow.), Nerinsea, &c, in the upper part ; and near the centre a very shelly bed, with Thecosmilia annularis (Flem.), Cidaris smithi Wr., Bourguetia striata (J. Sow.), &c. ... Soft sandy beds with Modiola, Pecten and Terebratula . . . 'Massive oolitic limestone, poor in fossils, with OervilUa aviculoides (J. Sow.), Ostrea, Exogyra nana (J. de C. beds, mainly composed of corals, Sow.) Cherty ' raggy Isastraea, &c. . '"Hard siliceous and ferruginous flaggy limestone, with \ Gervillia aviculoides, Exogyra nana, &c. .. 40 20 30 6 25 The Lower Limestone is seen on the coast as the capping to the faulted outlier of Scarborough Castle Hill, of which the description has been given in a previous section (p. 53). The peculiar rubbly bed which forms the lower portion of the Lower Limestone in the Hackness section is an impure siliceous limestone full of corals of the genera Thamnastraea and Isastrma ; it is, in fact, a ' coral rag,' occurring at a lower horizon than the Coral Rag so widely developed as part of the Upper Limestone in the country farther south (Sh. 54). The position of the band is indicated on the map by the printed words ' outcrop of coral bed.' The rock is best seen at Suffield, Silpho and Broxa, while there are indications that it extends as far westward as Bickley. Being hard and suitable for road-mending, it is quarried in several places, and is known to the workmen as ' Cold Head.' Blake and Hudleston in their well-known paper on ' The CoralliaD Rocks of England ' give the following description of one of these quarries and of the fossils 1 : — " Section of Suffield ' Sandstone ' Quarry." 'a. Soil and broken Rag ... 6. Crystalline gritty coral-doggers in a brownish brash con- taining abundance of small Waldheimia, with Spongia ■floriceps and many other fossils ... c. Massive coralline block with shell-tablets. Cidaris Smithii (spines and test), Trichites, &c. ... d. Flaggy shelly bed with a few corals imbedded in a brown gritty limestone e. Ferruginous brashy parting, with seams of ferric hydrate Ft. In. 6 3 1 9 8 3 1 Quart. Journ. Beol. Soe., vol. xxxiii, 1877, p. 331. CORALLIAN BEDS. 57 " The fossils of the Eag, chiefly occurring in b, are numerous and interesting. There are some peculiar forms of Ostrea. The list includes Ostrea, sp., 0. gregaria, 0. solitaria, Exogyra nana, Gryphcea cha,mceformis? Pecten fibrosus, P. articulatus (dwarf), Hinnites velatus, Lima rudis, Lima, sp., Trichites, Gypricardia (small), Astarte rhomboi- dalis (small), Waldheimia Hudlestoni, Cidaris Smithii, Spongiafloriceps, Serpula tricarinata. The corals present more variety than might be found in an equal amount of the Upper (true) Coral Rag of the district. We found Isastrcea explanata, Thamnastrcea concinna, The- cosmilia annularis, and Bhabdophyllia Phillipsi, with the inevitable Modiola inclusa." Above the Coral Bed the main mass of the Lower Limestone has at Hackness a thickness of about 30 feet. It consists of thick beds of oolite with sandy partings, and is distinguishable from the Upper Limestone by the paucity of its fossils. The following section in the outlier on the south side of Hackness Hall is quoted from Blake and Hudleston (op. cit.) : — " Section in Sotmeld Lime-quarry." " a. Thin bedded shelly limestones in which the forms are Ft. In. partially obliterated. Oerithiv/m mwricatuvm (rare), Exo- gyra nana, Ostrea grega/ria, Pecten fibrosus, Trigonia, sp. (rare), Echinobrissus, sp. (of. clunicularis), E. scutatus; fauna micromorphic... ... ... ... ... ... 4 b. Small-grained oolites with few fossils, forming the mass of the limestone ... ... ... ... 10 o. Fossiliferous suboolitic limestones with Ammonites cor- datus, Avicula insequivahiis (? expansa), Oervillia avicu- loides, Perna quadrata ; fauna megalomorphic. To floor of quarry, below which there may be some 6 or 8 feet before reaching the next series ... ... ... 3 6 17 6" West of the Derwent, the Lower Limestone has a narrow outcrop on the ' Low Moors ' of Ebberston and Allerston, and is cut into finger-like projections on the spurs west of Staindale. It thins rapidly northward in this quarter, for though over 50 feet thick in the hill above Allerston (Sh. 54) there cannot be more than 10 feet or so of the rock about Jingleby House at the northern edge of the outcrop. The Middle Calcareous Grit is an intercalation of sandy beds between the limestones, thin and unimportant to the south and south-east of the present area, hut expanding greatly to the westward. It occupies a small tract on the Hackness outlier, mainly around the hamlet of Silpho, where it gives rise to a red clayey soil with scattered fragments of sandstone and has been proved in numerous excavations. West of Troutsdale the Middle Grit, increasing in thickness, covers a wild sterile tract on Dalby Moor, of which only the indented northern fringe enters the present map ; and here the change from the heather-covered ground to the richer vegetation of the Lower Limestone outcrop is sharply marked. The numerous holes or pits scattered about these moors seem at first sight to be artificial, but more probably are ' pot-holes ' owing their origin to the sinking caused by dissolution of the calcareous beds below. At Pickering (Sheet 53) four or five miles south-westward of the area in our map, the Middle Calcareous Grit has attained a thickness of 40 feet. 58 MIDDLE OOLITE. The Upper Limestone, so far as the present map is concerned, is confined to two small patches on the Hackness outlier north of Hackness Hall. The eastern of these consists of only the lower heds of the subdivision, but the western, which is somewhat larger, contains the full thickness of Limestone with its Coral Bag, being covered at one spot by Upper Calcareous Grit. It is not easy to estimate exactly the thickness of the beds here, but judging from the contour of the ground and allowing for the dip, there seem to be about 40 feet of the Limestone and Eag. The Limestone is quarried on the right-hand side of the road going up to Silpho ; on the west side of the road the ground rises to a greater height, and the Eag beds come on, being imperfectly seen here and there amongst the grass, rising up in bosses which are perforated by the -borings of Lithodomi. Blake and Hudleston give the following details 1 of the section in the quarry just mentioned. Limestone Quarry, Bell Heads, Silpho. Ft. In. " a. Bubbly limestone fragments with occasional coral doggers in a reddish soil ; abundance of Phasicmella striata ... 1 6. Large-grained oolites in a bluish-grey calcareous paste. P. striata, Chemnitzia, Astarte Duboisiana, A. ovata, &c. . . . 7 c. Strong band of Thecosmilia-r&g — a kind of Coral shell-bed, showing a handsome arabesque of fossils. Spines of Cidaris Smithii in great abundance, quantities of Exogyra nana, Ostrea gregaria, Nerinsea, sp., Cerithium inornatum, Littorina rnuricata, Oylindrites Lhuidii [F], Area guadrisul- cata, A. pectinata ... ... ... ... ... ... 2 9 d. Thick-bedded large-grained oolites, similar in character to those above, but rather softer ; beds visible ... ... 6 3 17 0' The Upper Calcareous Grit is only present at the one place men- tioned above, on the hill south of Silpho, named Loffeyhead Heights on the six-inch map. Its lithological character along its northern outcrop in the country west of the present map is that of a soft rubbly ferruginous sandstone of a brownish-red colour. On the Hackness outlier it is very imperfectly seen, and apparently of slight thickness. The only evidence of its presence is derived from the fragments scattered about the fields on the high ground above the limestone. Blake and Hudleston mention (op. cit., p. 330) that an apparently bedded mass at this place contained the following charac- teristic fossils : — " Ammonites hiplex, Pecten midas, Avicula ovalis, var. obliqua, two species of Lucina, Thraeia, Pleuromya, Sec." As a whole the Corallian rocks of the district indicate that during their deposition the area was covered by warm shallow seas with local coral-reefs and shell-banks and a profusion of marine life, while the action of currents led to the formation of limited sand-banks, with many minor local changes of condition. Full lists of the fossils, particularly rich in species in almost all the forms of marine life, will be found in the memoirs previously cited (' Jurassic Eocks,' vol. i, chaps, xiii. and xiv. ; and ' Scarbro," chaps, iv. and v.). ' Quart. Journ. Geol. Soc, vol. xxxiii, 1877, p. 330. 59 CHAPTER V. A PAL.EONTOLOGICAL classification of the JURASSIC ROCKS OF THE WHITBY DISTRICT; WITH A ZONAL TABLE OF LIAS AMMONITES. By S. S. Bookman. Introduction. As the result of long-continued work by many investigators on the ammonite-fauna of the Jurassic rocks in England and on the Euro- pean continent the strata have been divided throughout into a suc- cession of zones marked by the occurrence or predominance of particular forms or species of ammonites. The sequence of zones, so far as it pertains to the formations present in the area under descrip- tion, is given in the following table (I), along with the equivalents of the zones in the local stratigraphy, and in the older zonal classification of the Lias adopted on the map and in the previous edition of this memoir. In the older classification just referred to, the ammonites were grouped roughly into ' species ' without close discrimination, and the numerous names of fossils that are engraved on the two maps in the sea-space opposite the fossiliferous coast-sections are in accordance with this method. Later work has shown, however, that few of the ' species ' thus named have been distinguished with sufficient accuracy for modern palfflontological purposes. Therefore it became necessary to introduce a new and more exact nomenclature, entailing much sub- division of the older ' species.' The relation of the new nomenclature to the old names on the maps is indicated in another table (Til, P- 65) where the new and old names are arranged in parallel columns. As the subsequent discussion of the evidence will show, it is in the practically unbroken marine sequence of Liassic sediments that, in this district, the zonal method has yielded the fullest and most definite results. In the Lower Oolites the application of the method is hampered by the absence of the determinative fossils in the thick masses of strata of estuarine or freshwater origin, and by their comparative rarity even in the intercalated marine beds. The Middle Oolites are somewhat more favourably circumstanced, but the zonal work as yet done upon them has not been sufficient to complete the scheme. In the following pages the localities where the various subdivisions are best exposed are briefly mentioned in the notes immediately under the first Table. The stratigraphical series is next considered in fuller detail, in upward succession. With respect to the Lias, the descriptive sections numbered [1] to [5] give particulars of the whole succession and of the zonal divisions from the lowest exposed beds of the Lower Lias up to the Dogger. The lithological details and measurements in these sections are for the most part reproduced from the former edition of the present memoir. The Oolites, for reasons stated above, are not particularized in the same manner, but are discussed in more general terms ; therefore the reader should refer to the preceding chapters, III and IV, for the stratigraphical particulars of these rocks. 60 PAL.EONTOLOGICAL classification. I. — Table of Ammonite Zones with their Stratigraphical equivalents. Middle Oolite and Cornbrash. Zones. Strata. Divisions and Zones in THE 1st Edition. id pseudo-cordatus decipiens wartse martelli biarmatum vertebrale ^scarburgense | Qxford 01 ' vernoni > gregarium "1 vertumnus renggeri _ lamberti athleta ornatum Upper Calcareous Grit Upper Limestone "} Middle Calcareous Grit > Coralline Oolite Lower Limestone J Passage Beds Lower Calcareous Grit calloviense koenigi ^macrocephalus Non-sequence ' Kelloway 'Rock non- sequence Cornbrash Lower Oolite. { acuminata 1 @ fusca v< m zigzag schloenbachi truellii garantiana "niortensis Teloceras Stepheoceras Stephanoceras Stemmatoceras sauzei Witchellia Shirbuirnia post-discites discites g ( concava •g \ bradfordensis ^ 1 murchisonae <] (.Ancolioceras Non -sequence Upper Estuarine Series The Moor Grit should > represent some or all of these zones Grey Limestone Series Position of Middle Estuarine Series [ Millepore Bed \ Lower Estuarine Series j with Eller Beck Bed The Dogger P The Nerinaea Band f Dogger 1 This specific name refers to Oitrea acuminata, there being no available ammonite- species. TABLE OF ZONES. 61 Table I concluded — Lias. .a h ^ ] struckmanni (.striatulum ''variabilis lilli brautrianum fibulatnm suboarinatum psendovatum falciferum exaratum _tenuicostatum a f acutum o •£ J spinatum fl • ] margaritatum ° (.algovianum r oapricornum ") (Oiseoceras) 1 ) striatum g _ valdani " jamesoni pott urn armatura i^rarioostatum f oxynotum c3 stellare § I obtusum g ■{ birchi § I semicostatum ££ I gmuendense (^rotiforme Divisions and Zones Strata. in the 1st Edition. f Blea Wyke Sands f Zone of A. striatulus The Yellow Sands The Grey Sands | The Striatulus Shales ] The Peak Shales ( Cement Shales ) . J The Main Alum Shales j A " ' The Hard Shales ) The Bituminous Shales > A. serpentinus zone communis zone The Jet Eock The Grey Shales > Ironstone Series f Sandy Series > Ironstone Shales Pyritous Shales > Siliceous Shales > Calcareous Shales ? Not exposed r oxynotus zone bucklandi zone ) A. annulatus zone [ A. spinatus zone > A. margaritatus zone [ A. capricornus zone > A. jamesoni zone > '~ r o a. a, C3 On the details of this Table the following remarks may be made. The lines parting the zones and strata in certain cases indicate breaks in the stratigraphical isequence of the Yorkshire deposits : they show the places where there are non-sequences. Loweb Lias (Hettangian). — There are no exposures of these rocks in the district described ; but that they occur in the sea off Robin Hood's Bay can hardly be doubted. Species of ammonites 2 like Caloceras belcheri and C. convolutum from Robin Hood's Bay have either been brought in by the sea from submerged Hettangian scars, or had been transported by ice from the same area and left behind in the Boulder Clay. Loweb Lias (Sinemubian). — The lowest zone, that of rotiformis, is not proved to be accessible in Robin Hood's Bay, but the zones above have been reached, though very occasionally. The Obtusum-Oxynotum Zones are fully exposed at that locality, and are well known for several remarkable species of ammonites. 1 Since this chapter was written an excellent paper by Mr. W. D. Lang has appeared (Geol. of Charraouth Cliffs; Proe. Geol. Assoc, 1914, vol. xxv, p. 293). The detailed sequence of Lias strata there given for the South of England may well be compared with this Yorkshire table. Mr. Lang proposes the term Oistoeerat in place of caprieornt&s — a name preferable for many reasons. 2 For list of Ammonites see p. 100. 62 PAL^EONTOLOGICAL CLASSIFICATION. Lower and past of Middle Lias (Chabmottthian). — This is well exposed in Robin Hood's Bay. The Armatum Zone, which is exposed in the north cheek of the bay and also under the Peak, yields a remarkable series of ammonites of the genus Deroceras, many of large size ; they are comparable with those found at Radstock, in Somerset, and in the Rh6ne Basin in France ; but Robin Hood's Bay might almost claim pre-eminence for such a fauna. Middle Lias (Domeeian). — This is found on the coast at Hawsker Bottoms and the Peak. There is only a small exposure at the latter locality; but at the former there is a considerable development, richly fossiliferous. Uppee Lias (Whitbian). — This is exposed at Sandsend, at Whitby, and between the Peak and Blea Wyke. It is only at the latter place that it is found complete, or nearly so. At the other localities a considerable series of strata is wanting, having been removed from the upper part by denudation prior to the laying down of the Dogger. Consequently around Whitby there is a big break in the sequence between the Dogger and the immediately underlying Lias; and in places the Dogger contains fossils derived from the denuded Upper Lias. For its very rich fauna of ammonites in excellent preservation the Whitbian of Yorkshire is unrivalled. It is also famous for the Reptile and Fish remains which it has yielded (see p. 20). Uppee Lias (Yeovilian). — This series is only found at Blea Wyke and south of the Peak fault. Beds with a similar fauna are only found towards the South- West of England. The same remarks also apply to the upper beds of the Whitbian — the beds which are here described as the Peak Shales. Lowee Inferior Oolite (Aalenian). — At Blea Wyke, where the strata are most complete, there is a break between the Dogger and the strata upon which it rests — several zones are missing, according to Mr. Richardson. 1 Westward of the Peak fault, where the Dogger rests on Alum Shale, the break is greater ; all the Yeovilian and some zones of the Whitbian are missing. Middle Inferioe Oolite (Bajocian). — The important bed of this group of strata is the Grey Limestone Series to be seen at Blea Wyke, Cloughton Wyke, Harwood-dale, and other places. From the ammonite remains found in this series near Scarborough it can be dated as about the middle of the Bajocian, corresponding with strata which, with one not, certain exception in Lincolnshire, occur nowhere else in England, except in Dorset. Dr. Mascke, who has studied contemporaneous deposits in North Germany, 2 has divided them into several zones as shown in the Table; but these zones have in England been hitherto grouped into one, known as the Blagdeni Zone. The Moor Grit is rightly classed on the map. From its position it must represent zones of the . Upper Inferior Oolite ( Vesulian, in part) ; but how many, or which, is not known at present. The Estuarine Steata. — The plant-remains and coal-beds give the chief interest to these strata, which cover a considerable tract of country in the middle area of the district, with exposures also at Hawsker and Whitby. The Middle and Lower Estuarine Series must from their stratigraphical position represent more or less approximately the zones to which they are assigned in the Table. The Upper Estuarine Series is classed along with the Moor Grit in the map, as if it were the highest part of the Inferior Oolite Series. But the Upper Estuarine Series can be correlated with the semi-estuarine deposits (Neseran Beds) of Oxfordshire, and is, therefore, on the horizon of the strata of the Fullers' Earth, which belong to the zone of Osirea 1 Op. infra cit., p. 188. 2 K. Mascke, ' Coronatenschichten von Norddeutschland,' 1907. ZONES OF THE LIAS. 63 acuminata. The series may in part be equivalent to later rocks — Great Oolite; or there may be, as is more probable, a considerable stratigraphical break— a non-sequence — between it and the overlying deposit, the Corn- brash. Cobnbrash and Middle Oolites. — These rocks occur principally in the southern portion of the district. The chief localities are Scarborough (Castle Hill), which is just within the limit of the map, Hackness. Silpho, and Suffield. The zones of the Kelloway Bock and associated beds have been the subject of a recent study based on Yorkshire Ammonites (see below). The zones of the Argovian cannot be definitely assigned, as the zonal system of these Yorkshire strata has not yet been worked out. All that can be done is to place the succession of zones opposite the succession of strata without attempting to define limits. An exception is the case of the Vertebrale Zone, to which the Lower Calcareous Grit certainly belongs, in part, at any rate. The four highest zones of the Argovian are taken from a paper by Dr. Hans Salfeld; 1 and the term Biarmatum Zone is suggested to me by Dr. A. Morley Davies : it is in part the old Perarmatum Zone — a wrong identification of that species. The authorities for the modern zonal arrangement of the Yorkshire rocks are as follow : — 1910. S. S. Buckman, ' Certain Jurassic Strata ' ; Quart. Joum. Geol. Soc, vol. lxvi, pp. 81, 82. 1910. S. S. Buckman, ' Yorkshire Type Ammonites ' ; vol. i, p. xvi. A full Table of the Lias. 1911. L. Bichabdson, ' Lower Oolitic Bocks of Yorkshire ' ; Proc. Yorks. Geol. Soc, vol. xvii (3), pp. 185, 186, with ' Append. I, II,' by S. S. Btjckman, pp. 205-212. 1913. S. S. Buckman, ' Yorkshire Type Ammonites,' vol. ii, p. x. A full Table of the Lower Oolites. 1913. S. S. Buckman, ' The Kelloway Bock of Scarborough ' ; Quart. Joum. Geol. Soc, vol. lxix, p. 152. Zones of Kelloway Bock and Oxford Clay. Lias. In lithic characters the Liassic rocks of Yorkshire differ con- siderably from those of adjacent areas to the south, but they show much similarity with the strata of the Western Isles of Scotland. In regard to fauna, the Yorkshire rocks show many peculiarities, suggesting that during Liassic times there was little, if any, free direct communication between the Yorkshire and Midland areas. Lists of fossils hitherto published might not support the assump- tion; but as the Yorkshire species are worked out, especially in the case of the Ammonites, it is becoming recognised that the practice of identifying Yorkshire species with southern species, anu southern species with Yorkshire species is in many cases not justified, and has been a cause of much error. There is reason to suppose that the Yorkshire Liassic sea was connected with the North- West-German basin with a northward connection to a larger body of water, while the Liassic sea of " Certain Upper Jurassic Strata of England ' ; Quart. Joum. Geol. Soc, vol. lxix, 1913, p. 123. 64 PAL-EONTOLOGICAL CLASSIFICATION. South- West England was connected with the Paris Basin and with that of South-West Germany, the main body of water lying to the west. But in regard to the connections of the Yorkshire strata much further and much more accurate palaeontological work must be accomplished before definite conclusions can be stated. One of the first tasks for such purpose is to ascertain, by the method of detailed zonal subdivision now being applied by investigators to different areas, how much local peculiarity of faunas depends on geographical features, and how much is to be accounted for by absence of strata. While, however, there are such local peculiarities — to whatever causes they may be due — there is at the same time in various areas a general correspondence in the facies of successive stages. There is the time of Capricorn ammonites, the time of crenulate ammonites, and so on. The following Table II gives the sequence of such Ammonite facies, with special reference to Yorkshire. Table II. Stages and Ammonite Patinas. Stages. Ammonite-fat/nal Characteristics. (Yorkshire). Yeovilian Broad- whorled, keeled Ammonites (platyeones) dominant. Planulates absent. Whitbian Planulates — that is, unkeeled Ammonites of the communis type-and platycone Ammonites about equally dominant. Domerian Ammonites with crenulate keels (Amaltheids) dominant. Charmouthian Unkeeled forms — capricorns and tuberoulates — dominant. Echioceras is a keeled Capricorn. Sinemurian Keeled and furrowed Ammonites dominant, ending up as oxycones (Oxynoticeras; with doggers and calcareous bands, Gryfh&a cymbium Lam., Pteria inozquivalvis (J. Sow.) and Capricorn ammonites being the principal fossils. The section ZONES OF LOWER AND MIDDLE LIAS. 69 Zones. Capricornum (Total, 120 ft.) The beds 1 — 5 are marked on the map as Middle Lias (g 2') of them which is given below is taken from just round the Worth Cheek of Robin Hood's Bay. Other localities where they may be examined are mentioned in Chapter II under the heading of Middle Lias, Sandy Series (see p. 11). The following is a section of the strata now grouped under the term Charmouthian which comprises the lowest part of the Middle Lias, and the upper portion of the Lower Lias, as marked on the map, in other words from the Capricornum down to the Raricostatum Zones inclusive. In addition to personal observations, use has been made of the sections given by Tate and Blake, 1 and by Simpson, 2 as well as of the records given in the first edition of this memoir. [2] Section of the Chabmouthian. (Middle Lias lowest paet, and Lower Lias upper paet.) North Cheek of Robin Hood's Bay. (For upward succession see Section [3], p. 74.) Strata. Thickness. Ft. in. 1. Calcareous and ferruginous dogger band. Capricorn ammonites 6 2. Hard shale 6 3. Castle Chamber 3 , floor. Very hard ferru- ginous sandstone, containing layers of fossils 4 6 Dentalium giganteum, Phill., is very abun- dant in "the uppermost part. Oryph. cym- . bium Lam., belemnites and Capricorn am- monites abundant; Protocardia iruncata (J. de C. Sow.) is found occasionally. The Capricorn ammonites are species of Oistoceras — 0. figulinum, O. omissum, and another which may be Am. arcigerens, Phillips*. 4. Sandy shale with lines of doggers 23 5. The Oyster Bed. Thin sandy laminae passing into a calcareous band composed of Oryph. cymbium and Pteria inaequivcdvis, accompanied by Capricorn ammonites, Amberleya, EhynchoneUos and belemnites. 1 6 This bed is known as the large Oyster bed or the lowest Oyster bed. It runs out into the sea just south of Castle Chamber, then crosses the shore obliquely in a south-westerly direction and runs into the cliff. There is a marked stratigraphical change here. 6. Sandy shale with bands of doggers and nodules. Capricorn ammonites at intervals throughout. Lytocerata, quoted as " Am. fimbriatus," in the lower part. About ... 90 7. Shale with dogger bands 35 6 Ammonites such as Am. henleyi and Am. fimbriatus quoted from these beds presumably indicate Androgynoceras heterogenes and Lytoceras. Another more involute spacies of Androgynoceras occurs here, and Androg. macvlatum may be expected in these beds. 1 ' Yorkshire Lias,' 1876, pp. 73, 7tf, 91. a ' The Fossils of the Yorkshire Lias,' ed. 2, 1884, p. xix. * A small hollow in the cliff at high-water mark. 4 The Capricorn ammonites are like Oistoceras, but without tubercles. One speoies looks like Am. ai^gtiliferus Phillips, which, however, is perhaps a morphic equivalent in another genus ; another species, a common form with somewhat inflated whorls, may be what Hyatt has described as Microceras crescens. They are recogniz- able by having V-shaped peripheral costae not so strong as Oistoceras. Perhaps Hyatt's genus Amblycoceras covers them. See Zonal List, p. 95. Beds, 6 and be- low are marked in the map as Lower Lias (g 1) Striatum (Total, '35 ft. 6 in.) 70 PAL.EONTOLOGICAL CLASSIFICATION. Zones. Strata. Thickness. Ft. in. . 53 Pettum ? (taylori horizon). (Total, 44 ft. 5 in. 24 1 5 6 3 3 Valdani 8. Shales with lines of doggers, about ... (Total, 53 ft.) Ammonites such as Platypleuroceras aur- eum, P. rotundum, Polymorphites trivialis and other species occur here. , Jamesoni 9. Shales with irregular lines of doggers and a (Total, 23 ft.) strong dogger 8 in. thick at base 23 Ammonites of the jamesoni group ( Uptonia) rare and fragmentary. 10. Blue Shale, 10 ft., and ironstone dogge.r 8 in. 10 8 11. Blue shale, with pyritous nests full of fossils about 5 ft. down. .... 15 8 "Is at the base of the cliff, making the point to the south, of the north cheek of the bay." (Tate & Blake). Am. taylori quoted from this bed indicates it as the home of Phricodoceras cornutum and P. quadricornutum. Zeilleria hispidula (Simpson) = Waldheimia sarthacensis Blake in this bed. 12. Shale and doggers 18 1 13. Blue shale with doggers and nests of fossils scattered 14. Thin line of broken fossils 15. Blue shale full of belemnites and gryphseas 1 6. Ironstone dogger 17. Blue shale Am. tubellus is quoted from this bed. 18. The upper conybearei bep. Scattered irregular doggers and blue shale 3 Eehioceras aplanatum Hyatt sp. = Arietites tardecrescens Blake = Am. cony- bearei of collectors. 19. Argillaceous ironstone dogger with cone-in- cone structure at the top 4 20. Blue shale with Echiocerasmacdonnelli, about 8 6 Am. tubellus is quoted from this bed. 1 About this horizon Deroceras aff. miles 1 attached to a degenerate Eehioceras of the nodotianum type. Raricostatum ... 21. Sandy shales with indurated and Variegated (Total, 41 ft. 1 in.) bands, about 35 22. Three hard bands which run close together and form a feature in the cliff 2 3 23. Blue shales with line of fossiliferous nodules at base 3 10 The nodules contain Deroceras obsoletwm Blake, non Simpson (Am. densinodus Auott.), 8 D. noddblongum, Quenstedt sp., and Amm. of the raricostatum group (Eehioceras) ; also small ammonites with many whorls and many ribs which are like Am. subplanicosta Oppel. (For downward continuation see Section [1], p. 67.) With regard to these zones and their fauna, attention may be drawn to the following points. Armatum (Total, 44 ft. 8 in.) From about beds 13 — 16 according to Simpson's records come a number of species of Deroceras, D. subtriangulare, D. aculealum, D. marshallani, D. retusum, &c. 1 Young examples of Deroceras are easily mistaken for Am. tubellus, as was done by its original describer, Simpson. Am. tubellus is a small smooth adult to be assigned to the genus Bifericeras. 3 The species is much like Am. nodogigas, Quenstedt, pars, ' Amm. Schwab. Jura,' 1884, PI. xxvii, fig. 9 only. 'Am. obsoletus Simpson is a fine-ribbed Uptonia, and must come from a much higher horizon. ZONES OP MIDDLE LIAS. 71 The strata of the zone of raricostatum are probably incom- plete in Yorkshire as they are in so many other places. The species of Echioceras found in the Armatum Zone are possibly derived. The zone of armatum which can be seen at both ends of Robin Hood's Bay is of particular interest by reason of the fine series of ammonites of the genus Dernceras which it yields. The evidence for a zone of pettum between the zones of jamesoni and armatum is not good, but there appears to be an intermediate horizon characterised by species of Phricodoceras. Its limits can only be given approximately. It is possible that the Valdani Zone is incomplete in Yorkshire, for the absence of Acanthopleuroceras valdani and its allies is noticeable. What Yorkshire really shows is a zone of Polymorphites trivialis and allies, and it may be suspected that they are really somewhat earlier in date, suggesting a small stratigraphical break in Yorkshire. The capricorn ammonites which are a striking feature both of the Sinemurian and of the Charmouthian strata have not yet been worked out in the detail necessary for modern zonal correlation. They belong to many species and to several genera. At various times they develop rapidly into more or less involute spheroids (sphaBrocones) with double lines of tuberculate ornament; and they do this particularly in the Striatum Zone. There is then a great dissimilarity between the young and the adult; and only the young merit the title of capricorns. Some- times development is so rapid that even the capricorn stage rriay be omitted (Androgynoceras bechei). The presence of capricorn ammonites of the genus Oistoceras in the highest beds of the Yorkshire Charmouthian — in situ in the fioo'r of Castle Chamber — is an interesting palseontological fact, which may be of importance in correlating strata, and in marking the approach to the upper limit of the Charmouthian. It is a genus easily recognisable. Species of the genus are fotmd on the Dorset Coast in the Green Ammonite Beds. 1 (d) Domerian; acutum to algovianum zones {Middle Lias, main part) . The main mass of the Middle Lias constituting the Domerian stage is divisible as follows : — Table V. Summary or Domerian. Zones. Strata. Acutum ? ") Spinatum. > Ironstone series. Margaritatuni. ) Algovianum. Sandy series (upper part). , 1 They occur in the upper part of the Gieen Ammonite Beds according to Mr. W. D. Lang. {Op. oit., p. 328.) This author, it may be noted, adopts the following divisions of these beds which may be compared with those given in this Chapter, written before his paper was published : — Dorset (Lang). Yorkshire. Oistoceras subzone. Capricornum zone. Liparoceras subzone. Striatum zone. Lataecosta subzone. The Lataecosta horizon has not yet been recognised in Yorkshire ; but perhaps the lpwer part of the Striatum zone was contemporaneous. I 4 PAL^EONTOLOGICAL CLASSIFICATION. The Ironstone Series consists of shales with thin bands of iron- stone of variable thickness; the Sandy Series, of sandstones and hard shales with thick sandy beds of Gryphcea, Protocardia, &c. The change in the amrnonite-fauna from the Charmouthian is remarkable. Capricorn ammonites have disappeared, and their place is taken mainly by flat- whor led, carinate ammonites, of which the majority belong to the family Amaltheidae and show crenulate carinas. Species of Amaltheus are found in both the lower zones, bnt owing to the practice of noting them all by the one name margaritatus, exact information as to the specific distribution in the two zones is wanting. In the main, however, the more advanced 1 forms of Amaltheus are in the lower zone, and are followed by less advanced species in the higher zone, to be again followed in the still higher zone, spinatum, by a still less advanced series of the same family — namely, the genus Palto- pleuroceras — with an occasional much advanced species of Amaltheus. The same unfortunate use of a single name has obtained in regard to the species of the genus Paltopleuroceras : they have nearly all been noted under the name spinatus. But, so far as investigation of Yorkshire specimens has gone, no example of the massive-whorled P. syinatum has been found in this district. The usual species is a rather thin-whorled form, P. hawskerense. The evidence for the presence of the Acutum Zone in Yorkshire is not yet satisfactory. Certain ammonites' of the family Dactyloidce are said to come from the Ironstone Series ; they may indicate its presence; and a species of unknown horizon which seems to be allied to the zone-fossil suggests further probability. A fine section of the Ironstone Series may be seen on the coast from Normanby Stye Batts to Dobson's Nab, generally known as the section of Hawsker Bottoms, and continuing southward the upper part of the Sandy Series may be investigated. The follow- ing is an account of the beds so presented : — [3] Section of the Domerian (Middle Lias), Hawsker Bottoms, and southward. 2 (For upward succession, see Section [4 J, p. 76.) Zones. Strata. Thickness. Ft. in. Acutum ? ... 1. Layer of earthy ironstone, weathering into (Total, 2 ft. 9 in.) rounded doggers : Pecten cequivalvis J. Sow. (large), Belemnites, Pholadomya ambigua (J. Sow.), &c 3 2. Shale, yellow-tinged, soft and finely laminated 2 6 Spinatum 3 ... 3. Red ironstone dogger band; uneven top, very (Total, 34 ft.) fossiliferous. Paltopleuroceras hawskerense, Pecten osquivalvis (large), Belemnites, Modiola scalprum J. Sow., Pteria incsquivalvis (J. Sow.), Dentalium elongatum Muenster, Pholadomya ambigua, Protocardia truncata, Rhynchonellatetraedra (J. Sow.),&c, in nests* 5 1 More advanced is more catagenetic in this case. 2 The stratigraphical details are mainly those of the first edition. Some infor- mation from other sources has been utilized. 3 According to Tate and Blake Am. spinatus, that is Paltopleuroceras sp. does not occur above Bed 3. Op. cit., p. 127. 4 This is quite a characteristic feature of this band, wherever it can be examined. ZONES OF MIDDLE LIAS. 73 Zonks. Stbata Thickness. Ft. in. Margaritatus ... (Total, 61 ft. 5 in.) 4. The Indurated Shale Band. Band of finely- laminated shaly sandstone, cemented by carbonate of lime and iron, having the fracture of an ironstone : Paltopl. cf. costatum 5. Grey shale, finely laminated, with sandy streaks and occasional ironstone doggers : Phola- domya ambigua and broken specimens of Paltopleuroceras 1 6. Continuous band of ironstone of irregular thick- ness 7. Shale weathering to small pieces, with occasional ironstone doggers 8. Ironstone band with many fossils, especially Paltopleuroceras Base of high scar at Hawsker. 9. Shale i 10. Ironstone band, crowded with fossils : Palto- pleuroceras, large Pecten, &c, very abund- ant ; several species of gasteropods, &c. ... 11. Hard shale 12. Strong band of ironstone, very fossiliferous. From Tate & Blake's records there occur in this bed (their No. 14, p. 127) the following species : Paltopl. apyrenum (= Am. solitarius Blake), Amauroceras ferrugineum, AmaUheus reticularis, Ehynch. lineata, gasteropods and lamellibranchs 13. Hard dark shale, slightly sandy ... 14. Scattered dogger band ... 15. Shale 16. Continuous band of ironstone ... 17. Shale, with large Pecten cequivalvis, &c. 18a; Continuous band of ironstone, oolitic grains, Pleuromya, &c, 6 in. b. Dark micaceous shale, large Pecten, Belemnites, &c, 8 in. c. Hard grey ironstone, 4 in. , 19. Shale, hard at base, with Pecten, &c 20. Ironstone dogger band 21. Shale, with long flat doggers at base 22. Shale, slightly sandy, and containing aggrega- tions of Pecten, Belemnites, Gryphcea cymbium Lam., AmaUheus, &c. 23. Ironstone band, with shale parting in the middle Shale, more sandy than above, small scattered doggers containing Pecten liasianus Nyst ... Sandy ironstone, resting on a hard sandy band similar to the Indurated Shale Band : Gresslya intermedia (Simp.), Protocardia truncala, &c, abundant Shales, very hard and sandy in lower part, softer in the upper, with thin bands of ironstone : AmaUheus amaliheus, Protocardia truncata, &c : 24. 25. 26. 1 6 6 6 6 10 3 1 3 2 5 Pecten Seam 1 6 18 1 5 15 1 20 'According to Simpson's records his species PaUopleuroceras etoboralum and P. birdi occur in Bed 5 or above. ' Poss. Yorkshire Lias,' ed. 2, 1884, p. xv. ■ ■74 PAL-EONTOLOGICAL CLASSIFICATION. Zones. Strata. Thickness. Ft. in. Algovianum ...27. Thin calcareous sandy band, forms the top of (Total, 23 ft. Dobson's Nab : layers of Protocardia 10 in.) truncata, &c ... 10 28. Hard sandy shale 4 29. Calcareous sandy shale : Dentalium giganteum Phill., Oryphcea, Protocardia truncata, &c, abundant 5 30. Close-grained sandstone, ferruginous and cal- careous, containing four distinct bands of Oryphma, Cardium, &c 3 31. Hard sandy shale with Amaliheus, Pecten, Belem- nites, &c, in bands ... ... ... ... 2 4 32. Dogger band 4 33. Hard sandy shale with an eight-inch fossiliferous nodular band at base ... ... ... ... 3 34. Hard shale, darker than above : Pecten, Belem- nites, &c. 5 4 (For downward continuation see Section [2], p. 69.) According to Simpson's records 1 there come from the lower beds of the Algovianum Zone, Amaltheus clevelandicws and Seguenziceras nites- cens. He also quotes Am. bechii from the same beds, which may be Aegoceras nautili for me (J. Buckman). 2 (e and f) Whitbian and Yeovilian ( Upper Lias). Another thick shale deposit, ending off in sandstones, forms the, Upper Lias of the Yorkshire coast. Around Whitby the thick- ness of the shales is about 200 ft. ; but it has been estimated that there are nearly another 120 ft. of superior shale deposits belong- ing to the Upper Lias, which are only found in the area south, of the Peak Fault, followed by some 90 ft. of sandy strata also belonging to the same formation. On palseontological grounds these deposits have been divided into two stages — a lower one, Whitbian, in which planulate ammonites of the communis type are very abundant, and an upper one, Yeovilian, in which these planulates are not found. 3 Both on lithic and faunal characters much further subdivision is made : the strata of this district are separated into 10 noticeable deposits, and these represent 13 zones. 4 The old division of these strata was into three — Alum Shales, Jet Rock, and Grey Shales, with sometimes a fourth division added — Hard Shales. In some cases the Alum Shales included all the strata down to the Jet Rock, but in other cases the bitu- minous shales were placed with the Jet Rock and not with the Alum Shales. In other cases the term Jet Shales includes all the strata from the base of the Jet Rock to above the ovatus band. The term Hard Shales was sometimes applied to the shales of the ovatus band, sometimes to the bituminous shales, and sometimes to both. Thus, even when specimens have these labels instead of the old comprehensive term Upper Lias, it is not always certain which beds are referred to. The allocation of zones so far as the lower portion of the 1 'Fossils of the Yorkshire Lias ' ed. 2, 1884, p. xvii. J See ' Yorkshire Type Amm., '37. 8 S. S. Buckman, 'Jurassic Strata' ; Quart. Journ. Geol. Soc., vol. lxvi, 1910, p. 88 ; ' Yorkshire Type Amm.,' 1910, p. xvi. * See Table I, p. 61 ■. ZONES OF TIPPER LIAS. 75 Yorkshire Whitbian is concerned is fairly satisfactory, and as regards the highest part, the Peak Shales, much the same may be said. But how the Cement Shales and the Main Alum Shales — the strata which have produced most of the specimens labelled Alum Shales — are parted among the zones braunianum to sub- carinatum is not at present known. About the middle of the Upper Lias (Whitbian) strata there is a well-known double band called by collectors the " Am. oyatus band." The fossil is not the Am. ovatus of the first edi- tion of Young and Bird's work, but of their second, 1 wherefore it is not the true ovatus, but a false ovatus or pseudovatus — a name which has been introduced for the zone. 2 The fossil and its stratum would seem not yet to have been recognised outside Yorkshire. (e) Whitbian (Upper Liqs, lower part). The following detailed section of the lower part of the Upper Lias (Whitbian) is based mainly on that given by C. Fox- Strangways. 3 Zones. [4] Section of the Whitbian (Upper Lias). (For upward succession see Section [5], bed 11, p. 80.) Variabilis Lilli Braunianum Fibulatum Subcarinatum Pseudovatum Faloiferum Strata. t 2 Peak Shales with Haugia heard, &c, only found south of the Peak Cement Shales. Soft grey micaceous shale with cement nodules Main Alum Shales, Beds 3-7 (Total, 69 ft.). 3. Soft grey micaceous shale From Beds 2, 3 have been obtained HiW.oce.ras afl. hildense, Dactylioceras com- mune, D. aff. angulatum, D. aff. holandrei, Omloceras crassum Nuculana ovum. i. Lumpy calcareous band 5. Soft grey micaceous shales 6. Hard nodular band, irregular 7. Soft grey micaceous shales Hard Shales, Beds 8-10 (Total, 18 ft. 10 in.). 8. Indurated sandy band, sometimes forming a distinct line of ironstone 9. Shales somewhat harder and darker 10. The Ovatus band. Double line of pyritous doggers with masses of belemnites and con- taining the so-called Am. ovatus Bituminous Shales, Beds 11-17 (Total, 70 ft. 6 in.). 11. Hard blue-black shales, Harpoceras of the mvlgravium type, Inoceramus 12. Red indurated band with pyritous lumps... 13. Hard dark shale Thickness. Ft. in. ?60 18 16 15 20 18 10 15 15 1 S. Buckman, 'Jurassic Strata'; Quart. Journ. Oeol. Soc., vol. lzvi, 1910> p. 85. 137. S. Buckman, ' Yorkshire Type Amm.,' 1910, p. xvi. 3 ' Jurassic Rocks of Britain, vol. i, Yorkshire,' Mem. Geol. Surv., 1892, pp. 127, 76 PAL-EONTOLOGICAL CLASSIFICATION. Zones. Steata. Thickness. Ft. in. 14. Line of scattered doggers — 15. Hard dark shales with great numbers of fossils 20 Harpoceras of the trmlgravium type, Phylloceras, Dactylioceras, belemnites, Inoceramus. 16. line of pyritous doggers —7 17. Hard dark shales, forming the shore at SaltwickNab 20 Exaratum Jet Rock, Beds 18-22 (Total, 24 ft.). 18. Solid band of hard indurated shale 1 This weathers out on the shore into large tabular doggers ; it also forms the roof of the jet-workings. 19. Hard dark shales 6 20. Line of large irregular doggers some distance apart ... ... ... ... ... ... — 21. Shales with several rows of small doggers... 9 Forms the lower part of the jet-workings. 22. Hard dark laminated shales 8 Harpoceras exaratum, Eleganticeras elegans (Young & Bird). Tenuicostatum ... Grey Shales : Soft grey shales with Dactylio- ceras tenuicostatum, D. semicelatum and other species. Belemnites ... ... ... ... 30 (For downward continuation see Section [3], p. 72.) The Grey Shales,— This bed, which is the lowest belonging to the Upper Lias, is not rich in ammonites, but it yields certain species of fine-ribbed Dactyloids, specimens of which may be found in nearly every nodule forming a band about the middle part of the zone. "The Grey Shales," Tate and Blake remark, "present such physical characters as readily serve to distinguish them from the Jet Rock or Alum Shale, but have close agree- ment with the shales forming part of the Ironstone Series of the Middle Lias; however, the smoothness and darker colour of the latter, and more especially the distinct species of Ammonites in each, will enable one to separate them. The practical value ,of this knowledge is not to be underrated; and we know that in two instances a search for the Cleveland main seam 1 has been prosecuted in the lower shales of the Middle Lias, 2 in the belief that they were the Grey Shales, despite the palseontological evidence. to the contrary." 3 The physical characters are stated by the same authors as follows: — "The rock is a micaceous sandy shale of a coarser texture than that of the higher and lower beds — hard, compact, and bluish-grey where protected from atmospheric influences, but crumbling into small subrhomboidal fragments of a greyish colour in exposed situations." 4 The Jet Rock. — The term Jet Rock is used in this chapter in a more restricted sense than the older appellations of "Jet Rock Series," "Jet Shales," etc.; it is applied only to certain strata which immediately overlie the Grey Shales and are intimately ' Middle Lias, Ironstone SerieB. 3 'Yorkshire Lias,' p: 168. 9 Lower Lias (Charmouthian). 4 Lot, cit. ZONES OF UPPER LIAS. 77 associated with the horizon from which jet has been obtained. It is an advantage for the palaeontologist to work with restricted stratigraphical terms because he can thereby attain greater pre- cision in his records. The matrix of the Jet Eock is hard, dark and compact, with more or less of conchoidal fracture. These features may guide the palaeontologist to a certain extent in efforts to determine the horizon of specimens with old labels; but it is not easy, merely from the matrix, to separate specimens of the Jet Eock from those of the overlying strata now classed as the Bituminous Shales ; the latter, however, are sometimes lighter and less compact. From the palaeontologist's point of view the Jet Eock belongs to a Tower zone, that of Exaratum, and its ammonite-fauna is more typically characteristic of Yorkshire than that of the overlying Bituminous Shales or Falciferum Zone, which has a much wider geographical extension. As noticed in Chapter II, p. 15, these two zones can be distinguished, lithically, from the strata above or below, so that their outcrop can be followed. Classed together as Jet Eock Series they have been indicated by a different tint on the map. Further information about them and the jet industry are given in that chapter. The Alum (and other) Shales. — The shales above the Jet Eock up to and including the Cement Shales have so frequently passed under the name of Alum.' Shales that it is advisable to group them under one heading now, giving a short description of their different constitutents. The Bituminous Shales which overlie the Jet Eock are hard black or blue bituminous shales with bands of pyritous doggers. Ammonites of the genus Harpoceras, especially H, mulgravium, are characteristic, and among lamellibranchs Inoceramus is a noticeable fossil. The Hard Shales are hard and dark shales, which have on occasion yielded a small amount of alum. At the base is the double band with the so-called Am. ovatus. The Main Alum Shales are soft grey micaceous shales with irregular dogger bands. Large excavations have been made in them for the now abandoned alum industry. Dactyloid ammonites and species of the genus Hildoceras are characteristic. The Cement Shales are similar in character to those below them, but they contain nodules which have been used in the manufacture of hydraulic cement. In these shales and those immediately below Nudulana ovum (J. de C. Sow.) is a characteristic fossil : in fact, its occurrence is said to be in this district coincident with and indicative of strata 'which produce alum. All the shales mentioned above are first seen rising from the sea at Blea Wyke, where they are capped by the Peak Shales. It should be noted that north-west of the Peak Fault the Dogger is in contact with these shales, but that to the east of the fault " the Dogger is separated from them by a considerable series of Upper Lias strata — the top part of the Whitbian as well as the Teovilian. 78 PALJ50NT0L0GICAL CLASSIFICATION. The Peak Shales. — There is a considerable thickness of shales which occur only between the Peak and Blea Wyke : they are imperfectly known because, owing to various natural difficulties, they cannot be examined properly. But they produce a series of special ammonites, species of Haugia and allied genera, which are not found in other beds in the district. There is a rich fauna, though in the main it has been obtained from detached blocks. It will be more convenient to discuss these with the Teovilian strata following. The beds which are now classed as the Peak Shales are contemporaneous with the thick sandy strata of the Cotteswold Hills in Gloucestershire, known as the Cottes- wold Sands, which attain in some places a thickness of about 250 ft. (f) Yeovilian (Upper Lias, upper part). On the coast these strata are only found south of the Peak. They consist of grey sandy shales below passing into grey and finally into yellow sands. The break in the palseontological sequence does not coincide with the lithological change, but occurs in the midst of sandy beds — between the yellow sandy strata of the Blea "Wyke Beds (Teovilian) and the somewhat similar rocks of the Dogger (Aalenian) above them: there some zones are missing. 1 The Teovilian strata of Blea Wyke may be summarised as follows : — Ft, Blea Wyke ( Yellow Sands 52 Beds t Grey Sands 42 Sandy Shales .- 60 Below the sandy shales are the similar Peak Shales already described. The following remarks refer to the Teovilian strata and these Peak Shales. From the time of Phillips, who recognised that these strata were the equivalents of beds in the south of England which connected the Lias and the Oolites, and who regarded them all as belonging to the latter, there have, been different opinions by different authorities as to how much should be classed with the Lias and how much with the Oolite. Wright, the next to deal with the question, placed the greater part of them as Lias but subse- quent authorities placed only a small part there. The differences of opinion are well set out in a table by C. Fox-Strangways. 2 The opinions expressed were, however, insufficiently founded. Two data were lacking — a detailed knowledge of the sequence of strata and of ammonite-faunas elsewhere, and a critical know- ledge of the Torkshire ammonite-species. The researches of the writer in the south-west of England, resulting in a detailed zonal table, supplied the first requisite; then an examination of the Torkshire ammonites, which are 1 Whether .they are found inland is doubtful. The strata called Dogger may include oertain Yeovilian deposits. But fossil evidence is not conclusive : the Dogger often contains many derived species'. 2 ' Jurassic Bocks, Yorkshire,' p. 150. • ■ ZONES OF TTPPEK, LIAS. 79 not too numerous in certain cases, settled the question within reasonable limits as to what strata were represented. 1 ,The question how the zones are to he divided between Lias and Oolite is of secondary consequence; the chief concern is which zones in the sequence are present and which are absent. So far, the sequence has been proved up to the Dumortieria Zone of the Yeovilian inclusive ; the highest zone of the Yeovilian and certain basal zones of the Aalenian are supposed to be wanting. 2 The following is a detailed section of the Upper Lias (Yeo- vilian) strata of Blea Wyke, showing also the beds upon which they rest and those by which they are succeeded. 3 [5] Section of the Yeovilian (Upper Lias, upper part) and Strata above and below (The Blea-Wyke Beds, &c), at Blea Wyke, Ravenscar. 4 Zones. Strata. Thickness. Ft. Aalenian 1. Sandstone, ferruginous, with scattered pebbles 10 Murchisonse. Anoolioeeras ? ... 2. Nerin^ea-Bed : numerous gasteropods and lamellibranchs 1 * # Non-sequence." # # Yeovilian ? Yellow Beds, Beds 3-6e. Dumortieria ? 3. Sandstone, greenish yellow, with' bands of pebbles 25 4. Brown shaly bed 1 5. Sandstone, brown, full of specimens of Tere- hratula trilineata Auctt. ; Trigonia ramsayi *' Wright, Qresslya donaciformis (Phillips) ... 2 Dumortieria ... 6a. Yellow Sands. Sandstone, yellow, with a band of belemnites and pebbles at the base 1 6. Sandstone, yellow, ferruginous 2 c. Sandstone, soft, yellow, shaly, Very con- spicuous 1 d. Sandstone, soft, yellow, ferruginous, with irony knobs and concretions 20 In the lower part are numerous specimens of Pteria with Serpula, Rhynchonella eyno- cephala Auctt., &c. > 1 S. S. Buckman, 'Certain Jurassic Strata'; Quart. Journ. Oeol. Soc., vol. lxvi, 1910, pp. 81 et seqq. : ' Yorkshire Type Amm.' 1910, p. xvi. ; ' Upper Toaroian Beds ' (Appendix to a paper by L. Richardson) ; Proc. Yorlcs. Geol. Soc, vol. xvii, 1912, p. 209. 2 L. Richardson, ' Ool. Rocks Yorkshire,' p. 188. s The main part of this section has been taken with only little alteration from that given by L. Richardson, ' Lower Ool. Rocks Yorkshire ' ; Proc. York. Geol Soc., xvii, 1912, p. 188. The basal part of the section has been constructed upon the evidence given t>y Hudleston, ' The Yorkshire Oolites, Part I,' Proc. Geol. Assoc, vol. iii, 1874, p. 295, and on the fact that several species of ammonites characteristic of the highest zones of the Whitbian (Lilli, Variabilis) have been obtained from the neigh- bourhood. * For further information on this important section, vide Tate and Blake, Yorkshire Lias, p. 19; Dr. Wright's paper, Quart. Journ. Geol. Soc, vol. xvi, p. 1 ; C. Fox- Strangways, Mem. Geol. Survey ; ' The Jurassic Rocks of Britain,' Parts I, II, Yorkshire, 1892, pp. 149-178 ; R. H. Rastall, Quart. Journ. Geol. Soc, vol. lxi (1905), pp. 441-^460 ; and R. S. Hemes, ' Geology in the Field, East Yorkshire,' Geol. Assoc. Jubilee Volume, Part HI, 1910 ; also Proc. Geol. Assoc, vol. xix, part 10, pp. 410-445. * This is where Richardson puts the break in the stratigraphical sequence ; but the date of Beds 3-5 cannot be considered as proved yet. There is no doubt about the date of Bed 6. 80 , PALJEONTOLOGICAI/ CLASSIFICATION. Zonbs. Strata. Thickness. Ft. e. Soft rotten band with blue shaly clay and large lump-like masses of sandstone ... 1 From " top of yellow sands " there is Dumortieria munieri Haug. collected by R. _ Etheridge. From the strata 6 a-e have been obtained specimens of Dumortieria exlernicostata (Branco), D. aff. multicostata S. Buckman, Polyplectus cf. pietralatce Parisch and Viale, and Pseudolioceras cf. gradatum S. Buckman. Dispansum ... Grey Sands, Beds 7-9 Serpula BbiJs, Nos. 7 a-c. " la. Sandstone, grey, with a much-runnelled surface ; 4 Rhynchonella cynocephala, Auctt., Tere- bratula sp., Aulacothyris blakei (Walker),' Lingula beani Phillips, Dentalium elongatum 1 Muenst., Pteria insequivalvis Auctt., Pecten sp., Fucoids 2 spp., Lignite. 6. Brown ferruginous band with a layer of belemnites at its base ; often not much more than a parting 1 c. Sandstone, grey, false bedded, Very micaceous, with a band rich in Serpulce at the base ... 5 J Lingula Beds, Nos. 8, 9. 8. Sandstone, grey, shaly 25 At 4 feet from the top is a line of nodule- like burrs containing Phlyseogrammoceras dispansum (Lycett), 2 Hudhstonia affinis (Seebach), H. aff. affinis, Lingula beani Phillips, Pinna cuneata Phillips, Cerithium quadrilineatuin (Roemer), &c. 9. Shale, soft grey, with Lingula at the base ... 7 From the Grey Beds 7, 8, 9 have been obtained: Pseudolioceras sp. n., Hudleslonia wykiensis S. Buckman, H. cf. wykiensis, Glyphcea birdi Bean MS., Orbiculoidea • reflexa (J. de G. Sow.). From Bed 8, with Lingula attached : — Pseudolioceras cf. wurtlenbergeri (Denck- mann). Struckmanni Striatulus Shales, Beds 10, 11. Striatulum 10. Shaly rock full of spangles of white mica ... 60 11. A band of limestone-nodules full of Pteria (Pseudomonotis) substriata (Muenst.) ... — From the Striatulus Shales have come - Qrammoceras striatulum, O. toarciense, and other species ; Pseudogrammoceras latescens, &c. Whitbian 12. Peak Shales. Shales with Haugia, Denck- Variabilis mannia, &c. The Upper " Nucula " bed.... 60 Lilli Braunianum ? 13. Cement Shales ? Aluminous rock with and below. Hildoceras ... .>. ... 20 , 14. Main Alum Shale ? Alum Shale with "Nucula ovum." The Lower "Nucula" i Bed 20 For downward continuation after Peak Shales see Section [4], Bed 2, p. 75. 1 The present writer has reason to suspect that Walker's species is not an Aulacothyris, and not even a Dallinine ; but a Terebratulid in the sulcate stage. " P, dispansum (Lycett), " a few feet above Lingula beanii bed " ; coll. R. Etheridge. ZONES OP UPPER LIAS. 81 The description which Hudleston gives (p. 295) may be set out as follows, using his names for fossils r — Feet. 8, 9. Lingula Bed. 10, l'L. Grey sandy shales, Striatulus Beds 50 12. Strata with NuculaaS.ovum, Ammonites variabilis (insignia). OressVya abducta, Trigonia literata. . . 60 13. Aluminous rock with Ammonites Walcottii ... 20 14. Alum shale with Nucula ovum ... ... ... 20 With regard to the Beds 12-14 and the section set out from Hudleston's description, the thicknesses are said to be only approximate. But the exact thickness is not an important matter. The point to be recognised is that below the Striatulus Shales and above the Cement Shales there must be a series of strata of more or less thickness which have yielded the Am- monites of the variabilis group (Haugia, &c). The important point is to know exactly where in the sequence to look for these beds. The bed No. 13 with Hildoceras (Ammonites walcotti so-called) may he the equivalent of the Cement Shales, or may be a portion of the Lilli Zone and the Hildoceras may be H. semi'politum,. In that case the equivalent of the Cement Shales is to be looked for in Bed 14. Hudleston's thicknesses, though admittedly estimates, are probably fairly correct, as at the Peak there is a thickness of about 300 feet from the top of the Dogger to the Jet Rock. The Striatulus Shales are rather more argillaceous and darker in colour than the beds above them; and they contain bands of impure ironstone with a blue oolitic grain. These beds, and the Peak Shales have also been called the Jurensis Beds or the Jurensis Zone (see ante, p. 21). The Lingula Beds (Nos. ' 8, 9). — 'The most important point about these strata for fixing their position in the zonal sequence is the line of burrs about 4 feet from the top with the species of ammonites mentioned in the . section. The chief place for Lingula beani is a thin band of ferruginous sandy nodules near the base of bed 9 : this is known as the ' Lingula Band,' and is almost composed of the fossil ; but the species also occurs through- out the beds, "and higher (see Bed 7). The Serpula Bed (No. 7). — This bed of grey sandstone or sandy- shale is connected with the bed below by the presence of Lingula beani. The bed is also known to geologists as the ' Vermetus Bed ' ; it obtains its names from containing great numbers of Vermicularia [Vermetus^ coni/pressa (Y. and B.) and Serpula deflexa Phill., a feature sufficient to distinguish it at once. The bed forms the base of the cliff at the sharp corner and, running out over the upper part of the scar, shows a rough irregular surface, covered with the remains of these fossils, as well as Avicvla, Belemnites, &c. The Yellow Sands. — Bed 6 is usually known as the Yellow Sands, a point to be remembered in reading the old labels of fossils. From it have been obtained several species of am- monites of the genus Dumartieriu, which fix its date accurately 82 PAL-ffiONTOLOGICAL CLASSIFICATION. and indicate its correlation with the middle part of the Cepha- lopod Bed of Gloucestershire and with the Yeovil Sands of Somerset and Dorset. The Terebratula Bed. — Bed 5, which consists of 2 feet of soft brown or yellow sandstone crowded with fine casts of a Tere- bratula, is usually called the Terebratula bed. The Terebratula has generally been called T. trilineata, Young and Bird; but there are several species involved. One of them is presumably Young and Bird's species, but, until the identity of their type has been established, there can be no certainty on this point. The species can only be cited as T. trilineata Auctt. The Beds Nps. 3-5 are placed by Mr. Bichardson as his Yellow J3eds which, with No. 6, the Yellow Sands, he definitely assigns to the Dumortieria Zone. There is some probability for this view; but, so far as the ammonite-evidence is concerned, Bed 6 is the only bed of these which can be exactly dated ; the correla- tion of the beds above it must yet be regarded as unproved. The Peak Fault. The coincidence of the Peak Fault with an extra thickness of Upper Lias strata to the east of it has given rise to the supposi- tion that the fault has been concerned in some way in the pro- duction of these beds (see p. 21). Thus it was long ago sug- gested by Hudleston that this fault was connected with the sudden thickening of the beds between the Oolite and the Lias at Blea Wyke, and the idea has been recently revived by Mr. R. H. Rastall in his paper on the Blea Wyke Beds. 1 The suggestion, however, based on the limited evidence from a single locality involves many impracticable suppositions. Moreover, the facts to be explained do not arise from the thickening of beds, but from the presence of additional beds not found elsewhere in the neighbourhood. The preservation of strata in one locality and their absence from neighbouring places is now known, through exact zonal work, to be a common phenomenon, and as it occurs without faults, the coincidence of a fault may be only an accident. The preservation of Strata may be due to synclinal folding ; the absence of strata to erosion of the anticlinal folds. When move- ments take place soon after the deposition of the strata, and the erosion is done soon after the deposition, such erosion is called penecontemporaneous. If the movements are gentle, there may be no faulting; if they are more abrupt, the strain becomes excessive, and there is faulting. In the Peak case the movements must have taken place about the end of the Lias and the erosion was finished before the deposition of the Dogger, for the Dogger lies continuously and impartially over the more and the less denuded strata. The synclinal area lay to the east or south-east of the. Peak, and an anticlinal area lay to the west or north-west. In the synclinal area the strata have been preserved, but from the anticlinal area there was much removal by erosion before the deposition of the Dogger. And tliere must have been a fault 1 Quart. Journ, Oeol. Soc, vol. bri, 1906, p. 441. ZONES OF LOWER OOLITES. 83 somewhat along the line of the Peak Fault, for the denudation does not increase gradually oyer a curving anticlinal area, but it is abrupt. Bast of the Peak Fault there is about 300 feet of strata between the top of the Dogger and the^op of the Jet Rock; but immediately west of the Peak Fault there is only about 100 feet of strata intervening, so that the fault was about 200 feet or more when the Dogger was deposited. Subsequent faulting has shifted the Dogger about another 300 feet which makes up the amount of the present Peak fault. North-westwards towards Whitby there is greater thickness of Upper Lias — about 150 feet from top of Dogger to top of Jet Rock, — so that the anticlinal axis is passed and another syncline may be commencing. This, however, is truncated by the Whitby Fault, west of which there is a big depression at the present. Farther north-west, near Sandsend, there is about 175 feet from top of the Dogger to Jet Rock, which may be the farther side of a possible pre-Dogger syncline between Sandsend and Whitby. Lowee Oolites. The wealth of ammonites which characterises the Liassic strata of the Whitby district renders the labour of the zonal palaeontologist fairly easy. But after the Striatulus Shales are passed the ammonite-fauna rapidly declines; and when the Lower Oolites are reached, or even before, the task of zoning is rendered difficult, because, except in the Grey Limestone Series, there is little or no ammonite-evidence. Then zoning cannot be carried out directly; it can only be accomplished by the in- direct method of correlation; and the details necessary for this purpose are at present hardly sufficient. It has to be remembered also that the Estuarine rocks yield no fossils through which accurate zoning could be made. It is only in the marine beds intercalated with them that such evidence may be expected ; and then the dates of the Estuarine rocks can only be inferred from their relative position before or after such marine beds. For these reasons only a few general remarks can be offered — sufficient to show that the correlation suggested for the Lower Oolites in Table I represents the most probable arrangement, at the same time admitting that it requires further confirmation. The arrangement of the strata into Aalenian, &c, stages has already been given, p. 60. The Dogger. The evidence respecting the zonal position of the Dogger (including the Nerinsea Bed) is as yet imperfect. Mr. E. Talbot Paris says : — " The association of Acrosalenia lycetti, Polycyphus deslong- champsi, and Stomechinhis intermedins in the Dogger confirms the view that this deposit is of murchisonce hemera." 1 The species mentioned, however, are recorded from the Dogger of Glaisdale, which is beyond the district described in this memoir. 1 ' Notes on some Yorkshire Echinoids ' ; Append. Ill to ' Lower Ool. Rocks, Yorkshire ' by L. Richardson, op. cit., p. 213. f2 84 PAL^EONTOLOGICAL classification. Millepore Bed. Mr. Richardson gives several reasons for placing the date of the Millepore Bed as discites or post-discites. He lays much stress upon the occurrence of a spinose rhynchonellid (Acanthothyris^) comparable with Ac. crossi (Walker) of the Lincolnshire Lime- stone; and quite rightly, for a spinose rhynchonella of an earlier date is a very rare phenomenon. 1 Grey Limestone Series. From the upper portion of the section at Hundale Point, Cloughton, Mr. R. S. Herries has obtained three species of am- monites which are referred with query to Dorsetensia. One may be D. romani (Oppel) ; another D. liostraca S. Buckman; the third is still more doubtful. 2 These species would appear to indicate that the upper part of the Grey Limestone Series can only be correlated with the lower part of the Blagdeni Zone of South England, not with the upper part. Other ammonites which indicate the zonal position of the series have been obtained from near Scarborough, south of the area now dealt with. They appear to have come from the lower part of the Limestone beds, and in the main indicate Blagdeni Zone, though there may be something lower. 3 Further work is required before exact correlation with the south of England or the more detailed divisions of North Germany can be undertaken. The belemnites might give help ; but little is known on modern lines about the zonal distribution of belemnites, and the identifi- cation of species cited from the Grey Limestone Series is doubtful. The series is " divisible into three main portions (see p. 38) : — (a) An upper portion in which shales predominate ; (6) A middle portion in which sandstone or grit is the main con- stituent ; (c) A lower portion in which . . . limestones . . . are most in evidence ;" according to Mr. Richardson 4 ; and these are again faunally charac- terised thus : — (a) Belemnites tp. (b) Isocrinoid ossicles. (c) Gervillia acuta Auctt. (ahundant). 5 When the series is "traced across Howedale Moor it is noticed that thin flaggy sandstones occur very persistently in the upper portion of the shale division (a), and are characterised more par- ticularly by a little Gryphcea (see Phillips' ' Geol. Yorks. Coast,' 3rd ed. pi. ix, f. 26). " 6 The Grey Limestone Series therefore may be grouped thus : — 1. Flaggy, or Gryphaaa Beds. 2. Shale, or Belemnite Beds. 3. Sandstone, or Crinoid Beds. 4 Limestone, or Gervillia Beds. 1 ' Lower Ool. Rooks Yorkshire,' p. 202. a S. Buckman, ' Amm. from the Scarborough Limestone ' ; Proc, Yorks. Geol Soc xvii, 1911, p. 207. 3 Richardson, op. eit. p. 195, and S. Buckman, id. pp. 205-208. 4 Op. tit. pp. 195, 196. " Gervillia scarburgemis Paris ; Richardson, op. eit. p. 195. " Richardson, op. tit. p. 196. ZONES OF LOWEE OOLITES. 85 One of the best sections of the three lower members of the Series is that exposed in the cliffs at Cloughton Wyke : details of the section at this place, and of other sections on the coast and inland farther north have been given in a preceding chapter (p. 38)'. H may be seen in the Cloughton Wyke section that the Grypheea Beds of the above divisions are probably not reached at the top ; that after about 10 feet down the underlying 40 feet or so represent the Belemnite Beds; that the sandstones lower down are presumably to be assigned to the Crinoid Beds; while in the lowest part of the section the Gervillia Beds may be noted. The three lowest divisions may be traced in other sections, and in some of them the presence of the Gryphsea Beds at the top is evident. It is rather an interesting coincidence that the Grey Limestone Series representing the Blagdeni Zone in a general way has thus been separated into four divisions, and that Dr. Mascke should have parted the contemporaneous strata of North Germany into four zones on the sequence of their ammonites. Moor Grit. From its position above the Grey Limestone Series (Bajocian, Blagdeni Zone) and below the main mass of the Upper Estua'rine Series (Vesulian, Acuminata Zone) the Moor Grit may represent some or all of the zones of the Upper Inferior Oolite (Vesulian) ; but this is only inference, there is no definite evidence. Upper Estuarine Series. There is good reason to suppose that the Upper Estuarine Series above the Moor Grit is the northward representative of the Neaeran beds and other semi-estuarine strata of the Midlands. As these, from their position, are known' to represent part of the Fullers' Earth (Vesulian, Acuminata Zone), it is reasonable to conclude that the Yorkshire beds are of the same date. In that case there is presumably a big stratigraphical break, or non- sequence, between the Upper Estuarine Beds and the Cornbrash. The other supposition, that Estuarine conditions continued in Yorkshire while the' marine conditions of the Great Oolite pre- vailed in the Midlands, might be difficult to hold for geographical reasons — the distribution, of land and water at the time and the relative proximity to the open sea. Cornbrash. The Cornbrash of Yorkshire represents only the upper portion of the beds which are considered to be Cornbrash in other parts of England — that is to say, it belongs to the Macrocephalus Zone. In other parts of England, especially in the south-west, this zone is often not present as Cornbrash — the calcareous strata of that name belonging to lower zones. It has been urged that the Macrocephalus Zone should, on faunal grounds, be grouped with the Callovian. In that case the Cornbrash of Yorkshire would not be the highest member of the Lower Oolites, but the lowest member of the Middle Oolites. 86 PAL.EONTOLOGICAL CLASSIFICATION. Its representation thus in Table I (p. 60) should, however, be regarded more as a matter of convenience than as an expression of definite opinion. Middle Oolites. The general zonal and stratigraphical arrangement of the strata of the Middle Oolites is given in Table I (p. 60), but the strata of the district have not been investigated in the manner required for precise zoning. Meanwhile, a few notes may be made on the results already attained, though these are based mainly upon observations in the area south of the present district, where the formations are more fully exposed. Callovian and Divesian {Kellaways Rode and Oxford Clay). The only coastal section of the Oxford Clay and Kellaways Rock is in the extreme south of the map, at Castle Hill, Scar- borough. The Kellaways Rock of this locality and of the adjacent North Cliff, just beyond the margin of our map, was once famous for its fossils. It is the locality which afforded many of the types described by authors, while others were obtained from the quarries at Hackness 1 (see p. 50). A study of the ammonites from these localities and from other places south of Scarborough has been made by the writer, 2 who put forward a scheme of zones into which he suggests that the ammonites can be arranged. In the main the scheme is con- firmed by the researches of other workers in other districts; but further study on the same lines is required. As pointed out in the last chapter (pp. 50-1), the stratigraphical changes implied in the names Kellaways Rock and Oxford Clay do not take place along any one particular zone. The rock changes laterally into clay or vice versa, which means that the same zone or zones may be Kellaways Rock at one locality and Oxford Clay elsewhere. The nomenclature, therefore, has regard only to the lithological condition; on palaepntological grounds the writer proposes to divide the strata into two stages, Callovian for the earlier stage where ammonites of the Cosmooeras style are dominant, and Divesian for the later stage where ammonites of the genus Quenstedtoceras flourished. This mode of division is, of course, independent of the local changes in the character of sediment, and is applicable to any district. The scheme proposed is shown in Table I (p. 60). It may be remarked that the Kellaways Rock of Yorkshire is in the main on a much higher level than the rock of the same name in Wiltshire : that is confined to the Calloviense-Koenigi zones of the Callovian. So, in the main, the species from the Kellaways Rock in the two localities are. quite distinct, and the bulk of the Yorkshire species or their equivalents are obtainable 1 J. Phillips, ' Geol. Yorks. Coast,' 1821, p. 139. a " The ' Kelloway Book ' of Scarborough " ; Quart. Journ. Oeol. Soc., vol. hax, 1913, p. 152. ZONES OF MIDDLE OOLITES. 87 not from the Kellaways Rock of Wiltshire, but from the over- lying Oxford Clay. It would really be an advantage if the Yorkshire rock were given a distinctive local name. When it is necessary to distinguish between the matrix of the Yorkshire and Wiltshire Kellaways Rocks, as, for instance, in determining the original home of derived fossils, it is a useful working rule to note that the Yorkshire rock is sandy and often in certain zones strongly oolitic, 1 while the Wiltshire rock is crystalline. Many of the species of ammonites from the Yorkshire Kel- laways Rock seem to be peculiar to the district ; while others show affinities with Russian forms. The Oxford Clay, as already remarked, is often an argillaceous modification, or rather con- temporary, of the Kellaways Rock in Yorkshire. One of its zones, the Vernoni Zone, seems to have no calcareous equivalent in the district; but little is known about it or its correlation. The other, the Scarbiygense Zone, will be noticed under the next heading (Argovian). Argovian {Corallian RocJcs). The remaining strata of the Middle Oolites described in this memoir have, with one exception, usually been classed in English literature as the Corallian Rocks. The term is fairly suited to the 'English rock-facies in " many localities,' but it fails con- spicuously in certain cases ; and for wider correlation it is quite unsuited. The term Argovian has the advantage of not being definitely descriptive. The lowest zone assigned to the Argovian, the Scarburgense Zone, takes its name from a species of Cardio- ceras. The lithic character of this zone in Yorkshire is argil- laceous, and it has therefore been included in the Oxford Clay; but on paJa^ontological grounds it is to be assigned to the Ar- govian stage, when that name is used to cover the strata which are distinguished by the presence of Cardioceras. Above the clay is the first bed of the so-called Corallian Series — a very distinctive arenaceous formation known as the Lower Cal- careous Grit. This has yielded many ammonites of the genus Cardioceras, and so it may with fair certainty be assigned, wholly or in part, to the zone of Cardioceras vertebrale. Perhaps this characteristic Mid-England species does not occur in the district under review, nor even in Yorkshire ; but some of its contem- poraries do. Arid among them may be noted Russian influence, as in the case of the Kellaways Rock species. C. rotundatum (Nikitin) is an interesting Russian species not yet known to occur in Mid-England. The zonal distribution of the remainder of the Yorkshire Coral- lian strata has not yet been worked out in detail ; for ammonites are scarce. All that can be done at present is to record in one column the stratigraphical divisions which have been made, and to place opposite to them the zonal divisions of the Argovian (see Table I, p. 60). The one and the other may then be bracketed 1 The matrices of the different zones have been described by the writer, op. cit. pp. 153, 154. 88 PALJEONTOLOGICAL CLASSIFICATION. without expressing any opinion as to detailed separation. As a coincidence there happen to be five divisions in each case ; but it is unlikely that they correspond except in a general way. For instance, Dr. Salfeld assigns the Osmington Oolite of South England to the Martelli Zone. 1 - Blake and Hudleston correlate the Osmington Oolite with a Yorkshire bed above the Middle Calcareous Grit. 2 This then suggests that the Upper Limestone of Table I belongs to the Martelli Zone; but as the Biarmatum Zone cannot be much above the Lower Calcareous Grit, probably no higher than the Passage Beds, if so high, this leaves the Middle Calcareous Grit and the Lower Limestone without zonal names. On the other hand, the two zones placed above Martelli may have on this basis no stratigraphical equivalents in York- shire; for Ringsteadia pseudo-cordatus, which gives its name to the Pseudo-cordatus Zone, is a species of the Westbury iron-ore ; and that deposit Blake and Hudleston (p. 390) correlate with the Upper Calcareous Grit of Yorkshire. 1 ' Upper Jut. Strata ' ; Quart. Journ. Oeol, Soc., vol. hrix, 1913, p. 428. * ' Corallian Rocks ' ; Ibid, vol. xxxiii, 1877, p. 389. APPENDIX. Zonal List of Lias Ammonites from Whitby District. The following zonal list of ammonites gives the species at present determined from the Lias of the Whitby district ; further work is still required regarding the identity of types and in the critical examination of specimens. It is not, of course, a list of the ammonites of the Yorkshire Lias, since the material from the important coast-sections of the Redcar district to the north, the numerous finds in the drift of Holderness on the south, 1 and the species from Cleveland and other inland Yorkshire localities have not been included. The species mentioned have been obtained mainly, if not entirely, from the coast-sections of the district described; the Lower Lias species from Robin Hood's Bay; the Middle Lias species mostly from Hawsker Bottoms, and in a small degree from the Peak ; the Upper Lias species from near Whitby and from the Peak, the species from the Peak Shales and higher beds (Lilli zoneand above) coming only from the strata exposed between the Peak and Blea Wyke. The zones to which the various species are assigned must in many cases be read with a query. This caution applies especially to the species of the Upper Lias (Whitbian), in which the zonal allocation of species is at present very incomplete. The zone in which a species may be found is not necessarily the zone in which it was originally deposited or the zone to which it is assigned in the list. It would be preferable, in fact, to read ' hemera ' instead of ' zone.' The hemera or period of time during which a species lived may, on account of derivation, be earlier than the zone in which, in certain cases, it is found em- bedded. It is as a record of the hemera? in which the various species presumably existed that the following list is compiled. Species which are Yorkshire types are marked with an asterisk. The descriptions and in some cases the figures of these species are to be found mainly in the works of Young and Bird (1822, 1828), Phillips (1829, 1835, 1875), Simpson (1843, 1855, 1884), and Tate and Blake (1876)— see ' List of Works,' pp. 134-5. Original figures or refigures of many of these types and others are given in the first fourteen parts of the writer's work on ' Yorkshire Type Ammonites,' now in course of publication (see 'List of Works,' p. 136) : such species are marked Y.T.A., with reference number, in the column headed ' Remarks ' in . the following lists, where also some other notes are inserted. I For a list of species from the Holderness Drift, see C. Thompson, Quart. Journ. Qtol. Soe., vol. lxix, 1913, p. 169. 90 PAL^EONTOLOGICAL classification. Ammonites of the Upper Lias (Teovilian). a • Zones Species 2 a I a Remarks o | 1 » s 3 & 3 1 • n DQ Alocolytoeeras Hyatt *peregrinum (Simps.) ... - * - - Y.T.A. 88. Dumortieria Haug externicostata (Branco) ... * - ~ - aff. raulticostata S. Buchn. * - - - munieri Haug * — - - Grammoceras Hyatt oomptum (Haug) - - - * penestriatulum S. Buckm. - - - * *striatulum (J. de C. Sow.) - - - * striatulum (Denckm.) ~~ ~~ ~ * Fauna Dornten, pi. vii, fig- 2. thouarsense (d'Orb.) - - - * Hudlestpnia iS. Buckman affinis (Seebach) •- * - - serridens (Querist.) - * - - 'simplex (Simps.) - * - - A dwarf species. * wykiensis S. Buchn. — * ~ ~ Proc. Yorks. Geol. Soc, 1911, vol. xvii, p. 211. Phlyseogrammoceras S. Buckm. dispansum (Lycett) - * - - *orbignyi (S. Buckm.) - * - - Pleurolytooeras Hyatt *gubernator (Simps.) - - - * Y.T.A. 70. perlaeve (Denckm.) - * - - Polypleetus S. Buckm. cf. pietralatae Parisch & Viale ... * - - - Pseudolioceras S. Buckm. *compactile (Simps.) - - - * Y.T.A. 41. faloodiscus (Quenst.) - - - * cf. falcodiscus (Quenst.) ~~ ~* ~~ * Aram. Schwab. Jura.pl.liv, fig. 48. cf. gradatum S. Buckm * - - - cf. undulatum (Quenst.) ~ ~ "~ * Aram. Schwab. Jura, pi. liii, fig. 2. cf. wurttenbergeri (Denckm.) - * - - Pseudogrammoceras 8. Buckm. explicatum ? S. Buckm. ...s - - - * ♦latescens (Simps.) - — * - Y.T.A. 79. Total 5 9 1 11 = 26. Total 26 species. This number may be expected to be greatly increased. tTPPEE LIAS AMMONITES. 91 Ammonites of the Upper Lias (Whitman). Zones Sfeoies 1 i I l 1 ■s <0 o ! •3 g TO ft © a 8 a s c3 -*a on O o S Remarks Coelooeras Hyatt ♦crassif actum (Simps.) ♦crassoides (Simps.) ... ♦crassum (Y. S B.) ♦crosbeyi (Simps.) ♦fonticulum (Simps.) ... ♦foveatum (Simps.) ♦puteolum (Simps.) Daotylioceras Hyatt anguinum (Rein.) ♦angulatum (J. Sow.) ... ♦commune (J. Sow.) ... ♦crassibundum (Simps.) ♦orassiusculosum (Simps.) ♦crassulum (Simps.) ... ♦delicatum (Simps.) ... ♦gracile (Simps.) helianthoides ? Yohoyama aff. holandrei (d'Orb.) raquinianum (d'Orb.) ... raristriatum (Quenst.) ♦semicelatum (Simps.) ♦tenuicostatum (Y.SB.) ♦vermis (Simps.) Denckmannia S. Buchman ♦obliquata(T. S B.) ... ♦rudis (Simps. ) Derolytoceras Rosenberg balteatum (Phill.) Eleganticeras S. Buchman ♦concavum (Y. SB.) ... ♦pseudo-elegans S. Buchm. Elegantuliceras S. Buchm. ♦elegantulum (Y. SB.) ♦rugatulum (Simps.) ... • ♦oVatulum (Simps.) ♦sigmiferum (Phill.) ... Frechiella Prinz ♦subcarinata (Y. SB.) Harpoceras Waagen elegans (J. Sow.) exaratum Wright ♦exaratum (Y. S B.) ... ♦mulgravium (Y. SB.) subexaratum BonareUi subplanatum Oppel ... * * * * - — * * * * * * * * • * '* * * * * * * * ? * * * * * * * * * * * * * Y.T.A. 89. Y.T.A. 60. Y.T.A. 59, Y.T.A. 69. Y.T.A. 61. Y.T.A. 62. Y.T.A. 107. Y.T.A. 31. Am. annulalus Auctt. Y.T.A. 68. Y.T.A. 14. Non Sow. ; cf. A. exaratus ; Phillips, Geol. York, xiii, 7. Y.T.A. II, p. viii. Y.T.A. 93. Y.T.A. 106. Y.T.A. 23. Lias Arnin., pi. Mi, figs. 1-3. Y.T.A. 5. Y.T.A. 4. 92 PAL^EONTOLOGICAL CLASSIFICATION. Species Zones Remarks Harpoceratoides 8. Buchm. ♦alternatus (Simps.) ... cfecilia (Blake) *ovatus(r. & B.) Haugia S. Buckman *beani (Simps.) patellifonnis S. Buckm. Hildoceras Hyatt *bifrons (Bruguiere) ... bifrons (Dumortier) ... chrysanthemum Yokoyama *hildense(F. & B.) .. laticosta Bellini levisoni Haug ♦levisoni (Simps.) serpentinum (Rein.) .. ♦walcotii (J. Saw.) Lillia Bayle ♦fabalis (Simps.) Peronoceras Hyatt ♦annuliferiim (Simps.).., ♦attenuatum (Simps.) ... cf. braunianum (a" Orb.) ♦fibulatum (J. de C. Sow.) *turriculatum (Simps.) . Phylloceras Suess ♦easingtonense (Simps.) ♦fabricatum (Simps,) ... *heterophyllum (J. Sow.) ♦labratum (Simps.) Phymatoceras Hyatt ' *pbillipsi (Simps.) Porpoceras S. Buckman ♦andraei (Simps.) armatum (Y. db B.) *orasaesoens (Simps.) ♦perarmatum (Y. & B.). ♦semiarmatum (Simps.) *subarmatum ( Y. & B.). ♦verticosum S. Buckm.... ♦vortex (Simps.) ♦vorticellum (Simps.) ... Pseudolioceras S. Buckman *boulbiense (Y. & B.)... ♦erratum (Simps.) ♦lectum (Simps.) ♦lythense (Y. db B.) ... ♦multifoliatum (Simps.). - - ♦ - Y.T.A. 9. ? Reineoke s Y.T.A. 15. Baasin Rh6ne, vol. iv, pi. ix, figs. 1. 2. Y.T.A. 12. Y.T.A. 63. Y.T.A. 30. Y.T.A. 34. Y.T.A. 85. Y.T.A. 57. Non Sowerby. Y.T.A. 50. Y.T.A. 91. Y.T.A. 29. Y.T.A. . 90. Y.T.A. 11. Founded on a cripple. Y.T.A. 43. Y.T.A. .13. UPPER LIAS AMMONITES. 93 Zones Species 03 a g 3 I a 3 1 +3 a o 3 CQ a g 1 © 8 1 a 3 s M XI a 1 OQ O O '3 1 Remarks PseudoliocerasS. Buchmc pseudovatum S. Buch *simile (Simps.) ♦subconcavtim ( Y. dk L aff. subooncavum (BM ♦whitbiense S. Buck Thysanooeras Hyatt ♦cornucopia (Y. & B.) dorcadis Pafisch dk Vial onychograptum S. Buck cf. sublineatum (Oppe Tiltoniceras S. Btwkman capillatum (Denckm.) Trachyrytocerau S. Buch fasciatum (Simps.) nitidum(r. ft c3 h Amblycoceras Hyatt 1 *oresoens (Hyatt) * ~ ~ — ~- — Pounded on a Whitby specimen and others s'p. (cf. A. anguliferus Phill. * Androgynoceras Hyatt cf. beohei (J. Saw.)... - * capricornum (Wright) - * - - 7- - - Plate xxxiv, figs. 1-3. henle^ (J'. Sow.) * A. heterogenous, Phillips, xii, 19. ' ♦heterogenes (Y. & B.) - * - - - - Y.T.A. 46. cf. hybrida (d'Orb.) - * - - - - - *maculatum (Y. & B.) - * - - - - - Y.T.A. 45. maculatum (Wright) - * PI. xxxiv, figs. 4-6. sirius (Beyne.s) — — — — — — * . Beanioeras S. Buehman *luridum (Simps.) * - - - - '— - Y.T.A. 73. Biferioeras S. Buehman quadricosta (Querist.) - - - - - - * Perhaps oxynotum zone. cf. subplanicosta (Oppel) ... - - - - - - * — — *tenuispina (Simps.) — ~ — - — - *. Perhaps oxynotum zone. *tubellum (Simps.) - - - - - * - *vitreum (Simps.) - - - - - * - .. Cymbitea Neumayr abnormis (Beynes) - - - - - - * Defossiceras S. Buehman *defossum (Bean-Simps.) ... * - - . - _ _ - Y.T.A. 76. Deroceras Hyatt *aouIeatum (Simps.) - - - - - * - Y.T.A. 72. *anguiforme (Simps.) - • - - - -^ * - Y.T.A. 64. *armigerum (Simps.) - - - - - * - ♦armatum (J. Sow.) - - - - - * - — . — fila ? (Querist.) - - - - * - ♦hamjltoni (Simps.) - - - - - * - *hastatum (Y. & B.) - - - - - * - Y.T.A. 102. *impavidum (S. Buchm.) ... - - - - - * - Y.T.A. 104. ♦marshallani (Simps.) -. - - - - * - A young form. "miles (Simps.) - - - - - * - Y.T.A. 44. *mutatum (Simps.) - - - - - * - Y.T.A. 105. *nativum (Simps.) ... - - - - - * - Y.T.A. 84. nodoblongum (Quenst.) - - - - - - * — — nodogigas (Querist.) - - - - - * - ♦obsoletum (Blake) "~ ~~ — — ~ — — * Not Simpson, see Uptonia; Am. den- sinodus Auott. LHyatt's name Amblycoceras is here used to denote capricorns with a peripheral rib curve lees than Oiitocerai (see p. 69). 96 PAL-EONTOLOGICAL CLASSIFICATION. Zones Species a 3 a 3 +3 Remarks S O i a .5 2 1 'i a o tS -J3 £ C3 © ^ (S a M > o» (3 t-t Deroceras Hyatt fc - ♦owenense (Simps.) * — Y.T.A. 65; a young form. *retusum (Simps.) * - Y.T.A. 82. *sinuatum (Simps.) * - Y.T.A. 94. 'sociale (Simps.) : - - — - - * - Y.T.A. 95. ♦spicatum (Simps.) - - - - - * - Y.T.A. 103. *subtriangulare (Y. & B.).... - - - - - * - Y.T.A. 71. *validum (Simps.) - - - - - * - Y.T.A. 83. Echioceras Bayle alpinum ? S. Buchm. - - - - - - * • *aureolum (Simps.) - - - - - - * Y.T.A. 96. boreale (S. Buchm.) - - - - - - * *oereum (Simps.) * Y.T.A. 49. ♦deoiduum (Hyatt) * A Whitby specimen cited as type ma- terial. ♦exortum (Simps.) ... - - — - - - * Y.T.A. 19. gracile (Querist.) - - - - - - * — . — macdonnellii (Portt.) - - - - - - * microdisous (Querist.) - - - - - - * aff. nodotianum (d'Orb.) ... — ~ — — — — * Base of Armatus Zone (derived ?). oosteri (Dumort.) - - - - — - * *regustatum S. Buchm. - - - - - - * Y.T.A. 28, and p. 96c. studeri (Hug) - _ - - - - * tardeoresoens (Blahe) - - - - - - * Liparoceras Hyatt ♦heptangulare (Y. & B.) ... - * - - - - - Y.T.A. 108. zieteni (Querist.) - * Lytoceras Suess ♦senex (Simps.)' - _ * - - - - Oistoceras S. Buckman ♦arcigerens (PhiU.) * ♦figulinum (Simps.) * - - - - - - Y.T.A. 26. ♦omissum (Simps.) * - - - - - - Y.T.A. 27. sinuosum (Hyatt) * - - - - _ _ — , Phricodooeras Hyatt *oornutum (Simps.) - - - - * - - Y.T.A. 32. . costatum (Querist.) - - - - * - - . ♦quadricornutum (Simps.) - - - - * - _ Y.T.A. 33. Platypleuroceras Hyatt *aureum (Simps.) - - * - • _ - _ Y.T.A. 3. «/. birohoides (Querist.) - - * - _ - - cf. grumbrechti (Schloenb.) - - * - - - — rotundum ? (Querist.) - _ * — _ _ _ Polymorphites Sutner-Haug caprarius (Querist.) - - * ' _ - - oostatus (Quenit.) - - * - - _ _ . cf. electre (Reynes) - - - ! - - - * interrupt™ (Quenst.) - - * - - _ jupiter (d'Orb.) - - * - _ . mixtus (Querist.) - - * 1 _ 1 _ - _ ♦rutilans (Bean-Simps J - - * ! _ ' _ - - ♦trivialis (Bean-Simps.) - ~ * - - - - Y.T.A. 53. MIDDLE AND LOWER LIAS AMMONITES. 97 Zones 8 | Species 3 E o 1 8 1 1 1' GQ 1 +3 a 1 3 4=» 03 43 m O Remarks i c3 > ■i. 0> ft u 3 Tragophylloceras Hyatt I ' 1 ! ♦ambiguum (Simps.) - ! - * _ - - - Y.T.A. 16. ♦huhtoni (Simps.) - * 1 - - - - ■ ♦nanum (Simps. ) - - * ', _ - — — numismalo (Querist.) _ I _ * i - - - - ♦robinsoni (Simps. ) — ! — * \ _ - - - . typioum ? S. Buckm. - - * - - - - weohsleri (Oppel) - - * ! _ - - - Tropidooeras Hyatt ♦antiquum ( Wright) - - j - - - - rotundum (Futterer) - - * - - - - . Uptonia S. Bucbn. angusta (Querist.) - - - * - - - aff. jamesoni (J. de 0. Sow.] - - - * - - - ♦ignota (Simps.) - - - * - - - Y.T.A. 21. ♦obsoleta (Simps.) - - - * - - - Y.T.A. 92. regnardi (d'Orb.) - - - * - - - ' ' I ♦ripleyi (Simps.) - " - * - - - Y.T.A. 2. Total 8 ! 9 1 21 6 3 22 22 = 91. Total 91 species, of which about 50 per cent, belong to the two lowest zones. 98 PAL.D0NT0L0GICAL CLASSIFICATION. Ammonites of the Lower Lias (Sinemttrian). Zones 4 Species a O m a Remarks 3 o 1 1 a s OS S J O o 1 1 a M ■§ o o 02 O 3 % OD H Aetomoceras Hyatt scipionianum (Blake) * — ' — ♦simpsoni (Bean-Simps.) ... * - Y.T.A. 66. Agassiceras Hyatt ♦personatum (Simps.) - - - - - - aff. personatum (Simps.) ... - - - - — — ' ♦resupinatum (Simps.) -' - - - - - Y.T.A. 6. aff. sauzeanum (d'Orb.) - - - — - - spinaries (Querist.) - - - - - - aff. spinaries (Querist.) - - - - - - eubtaurus (Reynes) .X. - - - — - terquemi (Beyries) - - - - - - ♦transformatum (Simps.) ... - - - - - - Y.T.A. 75. Androgynoceras Hyatt ♦integrioostatum (Simps.) ... * - - - - - - Y.T.A. 47. •siphunculare (Simps.) * - - - - - - Y.T.A. 48. Arietites Waagen oluniacensis (Beyn'es) ~ * — — — — — Mon. Amm., pi. xlv, figs. 36, 37. oollenotti (d'Orb.) - * ♦denotatus (Simps.) - * - - - - - Y.T.A. 67. impendens Wright ~ • Mon. lias Amm., pi. xxiiA, fig. 4. *impendens (Y. ds B.) - • - - - _ - . •lens (Simps.) * aff. lens (Simps.) * Cf. Am. oxynotus, Dumortier, Bass. Rh6ne, Vol. II, pi. xxxiii, fig. 3. •radiatus (Simps.) - * - - - - - Y.T.A. 35. ♦tenellus (Simps.) - * - - - - _ Y.T.A. 54. Arnioceras Hyatt •acuticarinatura (Simps.) ... - - - - * - - Y.T.A. 40. densicosta (Querist.) - - - - * - - difformis (Blake) - - - - * - _ hartmanni (Op-pel) - - - - * - - inoipiens Hyatt - - - - * - - cf. kridiforme Hyatt - - - - * - - kridioides Hyatt - ' - - _ * — — , — aff. miserabile (Querist.) ... - - - - * _ _ ♦multanfractum (Simps.) ... - - - - * - - — , — nigrum (Blake) - - - - * _ - cf. obtusiforme Hyatt - - - - * - - •semioostatum (7. & B.) ... * Interpreted as a species with a rather long smooth stage. * Vetustu m (Simps. ) - - - - * - - LOWER LIAS AMMONITES. 99 Zones Species a a 3 ■§ ID 0) Remarks 1 1 I =3 5 a 3 m 3 3 o 43 CO o o 1 s 3 a o '-3 o o 03 O 3 m u> Sh Asteroceras Hyatt *aoutioostatum (Wright) ... * = Aegoceras sagittarium, Blake, except in ventral View. margarita (Parana) - - * - - - - ♦redcarense (Y. dk B.) - - * - - - - ♦sagittarium (Blake) - - * - - - - aff. sagittarium (Wright) ... - - * - - - - Plate lii. sagittarium a (Wright) - - * - - - - Plate liiA. suevicum (Querist.) - - * - — - - undaries (Querist.) - - * - - - - Cheltonia S. Buckman aff. accipitris (J. Buckm.) * - - - - - - Coroniceras Hyatt meridional e (Reyries) - _ _ _ — _ * ♦obesulum (Blake) - - - - - * - ♦validanfractum (Simps.) ... - — _ — — _ * Cymbites Neumayr aff. berardi (Dumort.) - - * - - - - Gagaticeras S. Buckman ♦gagateum (7. » = io-i Domerian 35 j» 4 >» = 875 Charmouthian . . . 91 >> 7 »» = 13-0 Sinemurian 7S )3 t> » = 13-0 Hettangiau 14 „ 3 j» = 4-66 Total ... 335 „ 33 The average is just over 10 species to a zone for the Lias rocks of the district embraced in this memoir — not for all Yorkshire; the addition might be considerable, especially for the lower beds. The Whitbian and Charmouthian come out with the highest totals — the same number; but the Charmouthian shows the highest zonal percentage, perhaps because the Whitbian has been more subdivided zonally. The Charmouthian and Sinemurian both show the highest zonal percentage; just the same ratio. A comparison of the Yorkshire Lias ammonite-fauna shown in the above list with the faunas' of Lias districts of other parts of England may be made. The Lower Lias (Hettangian) fauna is negligible because the rocks are not actually exposed. The Lower Lias (Sinemurian) suffers, so far as its lower zones are con- cerned, from lack of exposure or from incomplete exposure. This may partly account for the absence of the large Arietids like Coroniceras buck- landi, rotiforme, rotator, multicostatum, and other species. Large speci- mens of Agassiceras are also lacking: the species recorded are small. Only one small Vermiceras comes for record, and the large degenerate Coronicerates of the Gmuendense Zone are not in the list, but it is possible that some of the species which have been called Am. bucklandi may really signify these. Lack or paucity of exposure cannot be urged to account for absence of species in the Obtusum and Stellare Zones, yet the large south-country species Asteroceras obtusum and Ast. stellare are lacking. Most of the species of Asteroceras are small. But the feature of the Yorkshire strata is the abundance of crippled or degenerate Asterocerates of the sagittarium pattern. They are almost special to the Yorkshire deposits : there are several species and many specimens, some reaching to a diameter of 7 or 8 inches. Above them are several species of involute Arietites. In the Oxynotum Zone there are many species of Oxyrwticeras, but the genotype itself, 0. oxynotum, is not recorded. The species found are small in the main, and the large forms of the 0. greenoughi and 0. guibali- anum types, which are not true Oxynoticerates, are rare or quite absent. A feature of the Oxynotum Zone of the district is the presence of Gagaticeras gagateum and similar capricorns; also of Parechioceras neglectum and P. finitimum. Their matrix seems to indicate this zone. The Lower Lias (Charmouthian) ammonite-fauna approximates on the whole to the faunas of the Midland and South- Western areas. Distinctive features are the abundance and the large size of Derooerates in the Armatum Zone — the fauna is remarkably rich; a scarcity of Uptonia in the Jamesoni Zone — a feature which it shares with the Midlands; the absence of Acanthopleuroceras valdani and allies — these are especially abundant in the Midlands; a scarcity of the striatum type, the sphaerocones of the LiparoceratidsB, but rather an abundance of the capricorns of this family. In the Middle Lias (Domerian) the special features of the Yorkshire deposits appear to be as follow : — Large species and specimens of Amaltheus such as are found in the Midlands and South- West are rare; similarly the large massive-whorled species of Paltopleuroceras of the spinatum type which is found in those districts is absent from this one : P. hawkskerense is the prevailing form, along with some rather degenerate species : the presence of Amawroceras ferrugineum and Amaur. lenticular e in the Spinatum Zone : these forms seem to be absent from other English localities, and they represent a special type. 102 PAL.EONTOLOGICAL CLASSIFICATION. In the Upper Lias (Whitbian) the number and variety of the excellently preserved Dactyloidae is a prominent feature : possibly the richness of the fauna is not to be equalled elsewhere. But there seems to be a deficiency of species of the brauniaimm style, which are common in the Midlands ; and, so far as is known, there is an absence of the mucronatum group. Other features of these strata are the fine examples of Frechiella ; and the number of species of Pseudolioceras — though several of them, like multifoliatum, simile, and perhaps subconcavum, possibly merit removal to new genera. P. pseudovatum, the Am. ovatus of Wright and others, is another species of which the same may be said : it does not seem to be known in the South- West or Midlands of England, but something like it is found in North- West Germany. In the Upper Lias (Yeovilian) the absence of species of the Maugia eseri group and the very limited number of the species of Pseudogrammoceras appears to suggest that there is a break in the stratigraphical sequence between the Striatulus Shales and the Grey Beds : where the Cotteswolds show about 20 species the Yorkshire strata have one. In other respects, with the possible exception of Hammatoceras, these Yorkshire strata show a fair sample of the ammonite-fauna of the time; and by more attention to the very limited and rather inaccessible exposure this number may be considerably increased. 103 CHAPTER VI. FOSSIL PLANTS OF THE LOWER OOLITE. General Account. In the foregoing description of the Estuarine Oolites frequent reference has been made to the occurrence of fossil plant-remains. On account of their variety and excellent preservation, these fossils ever since the early part of the last century have excited keen interest, and have given rise to a literature by which they have become known to palseobotanists in all parts of the world. The subject, therefore, requires some further notice in this memoir. Perhaps the most famous locality for these fossils has been Gristhorpe Bay, in the map (Sh. 54) to the south of the present area; but the cliffs at Scalby, Cloughton, Hayburn Wyke and Whitby, all within the ground described in this memoir, have also yielded much material ; and more recently the investigation has profitably spread to new ground inland, farther north-west- ward, in the neighbourhood of Marske (Sh. 34). At Gristhorpe Bay the band yielding the best fossils occurs in the Middle Estuarine Series; but north of Scarborough some of the most prolific plant-beds belong to the Lower Estuarine Series, and in other cases the horizon is doubtful owing to the difficulty in tracing the divisions separately (p. 36). Therefore, the flora of the Middle and Lower Estuarine Beds, which are known to have many species in common, will in the following pages be considered together and combined in a single list, while that of the Upper Estuarine Series, which is much sparser and of a somewhat different character, can be dealt with separately. The extent of the literature of the subject is partly shown by the list of the principal works at the end of the present chapter. The first quarter of last century was marked by the keen and successful collecting done, mainly at Gristhorpe, by several workers, particularly by W. Bean and J. Williamson, followed later by his son, W. C. Williamson. The material thus accumu- lated was studied soon afterwards by Brongniart, Phillips, Lindley and Hutton, W. C. Williamson, and numerous other writers; while, later, the work was continued by Bunbury, Leckenby, Williamson, Carruthers and others, as well as by several eminent foreign palseobotanists (see Bibliographical List at end of this chapter). It was in 1879 that Professor A. G. Nathorst began his investigation of these plant-bearing deposits, an investigation which has been continued with conspicuous suc- cess (see p. 104). Full lists of the plants, compiled from all the previous litera- ture, were incorporated in the general memoir on the Yorkshire Jurassic Rocks, published by the Survey in 1892; later critical 104 FOSSIL PLANTS OF THE LOWER OOLITE. re-examination of the original fossils by specialists has, however, considerably reduced the number of separate species mentioned in these lists. Toward the end of last century, Professor A. C. Seward under- took a revision of the flora, and in his ' Catalogue of the Mesozoic Plants in the Dept. of Geology, British Museum,' vol. i, pub- lished in 1900, he produced a careful summary of the subject in all its aspects, including the historical and bibliographical, with fresh descriptions and figures of many typical specimens. This standard work has been supplemented by Professor Seward in later publications (see Bibliographical List, pp. 111-12) which bring his revision up to a recent date. We are indebted to him for contributing the general note on the relations and conditions in- dicated by these plant-remains, which is printed as a prefix to the list of species given later in this chapter; and we have to thank him, and also Mr. H. Hamshaw Thomas, for having con- jointly revised the list. During the last few years there has been a strong recru- descence of interest in the Yorkshire Jurassic plant-fossils, an interest locally stimulated by the discovery of productive inland sites. Of these, the best-known and most prolific is that of TTpleatham Hill, about two miles south of Marske, to which attention was called by Mr. J. M. Meek, and of which descriptions have been given by Rev. J. Ha well, Rev. G. J. Lane and Mr. J. Burton (see pp. 111-12). Professor Nathorst and Dr. T. G. Halle of Stockholm have discovered new types, and Mr. H. Hamshaw Thomas, who is still engaged in a systematic examination of the Yorkshire plant-beds, has already added greatly to our knowledge of the flora. Further search along the inland outcrop of the Lower Estuarine Beds has also revealed the presence of plant-remains at Carlton Hill, Roseberry Topping and other places in Cleveland where the Estuarine beds form the summits of hills above steep slopes of Upper Lias shale; and it seems likely that the plant-beds will be traced farther southward under similar conditions, as for example in the upper part of Iburndale, within the present map (Sheet 44). Among other botanical problems which have aroused keen interest in association with this flora is that of the structure of the cycadean ' flowers ' known as Williamsonia. This problem has been especially studied by Professor A. G. Nathorst, to whom we are indebted for contributing the following note on the sub- ject: — " The chief object of my studying the fossil flora of the Yorkshire coast was the comparison with the Rhaetic and Liassic flora of Sweden (l). 1 But in consequence of my discovery of the flower of Williamsonia leckenbyi Nath. at Cloughton Wyke, my attention was directed towards this most interesting group of fossils (2). Visiting Whitby again 30 years later (1909) I was fortunate enough to discover a most beautiful male flower of what I have named Williamsonia spectabilis (3), being the first male flower of Williamsonia known. (What Williamson supposed to be the male flowers are in reality the female ones.) The synangia with the micro- spores (pollen grains) could be distinguished and the structure of the male sporophylls was shown to be almost identical with those of Cycadeoidea 1 The numbers (1), (2), (3), (4), refer to Prof. Nathorst's papers thus marked in the List of Works at the end of this chapter. THE JURASSIC FLORA. 105 described by Wieland. The female flower named Williamsonia leckenbyi was described and refigured and by means of the chemical method (maceration), also used for the male flowers, preparations of the micropylai tubes were for the first time obtained. Also from a specimen of Williamsonia gigas found by myself at Whitby the micropylar_ tube was obtained. A somewhat doubtful Williamsonia, named W. 1 lignieri Nath. was also described from Whitby. Being anxious to obtain further material, since many points were still obscure, I arranged that Dr. Th. Halle went to Whitby, 1910. His collection there was a great success, and the materials brought back by him were now described (4), and the former collections revised. It was shown that the species from the ' Lower Estuarine Series ' at Whitby were different from those of the ' Middle Estuarine Series ' of Cloughton Wyke. " From the former series the following species are now known : — Williamsonia spectabilis Nath. $. Williamsonia whitbiensis Nath. $. Williamsonia setosa Nath. $. Williamsonia ? lignieri Nath. $ or *. " Somewhat higher in this same series Williamsonia gigas is found, together with the leaves named Zamites gigas, while the other species of Williamsonia mentioned above are accompanied by leaves of Ptilophylliim pectinoides (Phill.) and Otozamites. " From the ' Middle Estuarine Series ' at Cloughton Wyke the following species are described : — Williamsonia pecten (Leckenby) $. Williamsonia leckenbyi Nath. 2- Williamsonia pyramidalis Nath. J or | . "It is possible that W. pecten and W. leckenbyi may be the unisexual flowers of the same plant. The leaves which are accompanied by these flowers are Ptilophyllum pecten (Phill.)." A. G N., Stockholm, 30th January, 1913. Professor A. C. Seward, F.R.S., has also kindly supplied the following notes on the fossil flora of this and the adjacent area : — " The Jurassic flora of Yorkshire is one of the richest of all Mesozoic floras. In general facies it agrees closely with the Wealden flora as represented by the plants obtained from the Sussex coast, the North German Weald, the Wealden strata of Portugal and from other regions. The flora included many ferns, some of which are very closely allied to species surviving in the southern hemisphere. The Jurassic species are specially interesting as affording evidence of the former abundance in Northern Europe of types which are for the most part now restricted to warmer and more southern countries. Equisetaceous plants were abundant and these agree closely, except in the larger size of their stems, with the existing European Horse-tails. " The most striking feature as regards the composition of the flora is the abundance and variety of the cycadean species. While many of the fronds, referred to such genera as Zamites (or by some authors to Williamsonia), Vioonites, Otozamites, etc., agree closely in habit with those of living Cycads, their reproductive shoots (Williamsonia spp.) differ widely from those of surviving members of the Cycadophyta. Recent work, particularly the researches of Professor Nathorst, have shown that the Williamsonia-&owers agree very closely in structure with the much more perfectly preserved Bermettites species from Lower Cretaceous and Jurassic rocks of England, France and North America. It is clear that the cycadean plants of Jurassic age differ considerably in the structure of their reproductive organs from the nine existing genera of the Cycadacese which are now almost confined to the tropical regions, Florida being their most northerly station. " Among the Conifers the presence of Araucarian types points to the abundance in Jurassic European floras of a family now restricted to South America and the Australasian region. The class Ginkgoales is represented by several species, the occurrence of which in other Jurassic localities demonstrates the cosmopolitan nature of the genus Ginkgo during part of the Mesozoic era, while at the present day it is represented by 106 FOSSIL PLANTS OF THE LOWER OOLITE. one species only, the Maidenhair Tree, which is not known to exist in an absolutely wild state, though its last home was undoubtedly China. " No satisfactory proof of the existence of flowering plants has so far been furnished by the records of Jurassic plant-beds. It is, however, not improbable that the genus Caytonia, recently discovered, but not yet fully described, by Mr. H. Hamshaw Thomas, may be a type of Angiospermous fruit. " Contrasting the vegetation of the Jurassic period with the British flora of to-day, and on the other hand with the vegetation of the Coal period, it may be said to stand out in striking contrast with the modern plant-world by the absence or at least by the rarity of Flowering Plants which subsequent to the Lowdr Cretaceous epoch became the dominant class. From the Permian and Upper Carboniferous floras those of the Jurassic and Wealden differ in many notable features. The Lepidodendrse and Sigillarise, which reached a height comparable with the pines, and other existing conifers, are represented in the Jurassic flora of England by fragmentary remains of what was presumably a small herbaceous plant closely allied to some of the small club-mosses and to the British species of Selaginella (S. spinulosa). The arborescent Calamites of the Coal period are reduced in the Jurassic vegetation to Equisetums much more allied to the modern Horse-tail than to their Palaeozoic precursors. " There is no satisfactory evidence that the Cycads, which bulk largely in Mesozoic, and especially in the later Mesozoic floras, had been evolved in the Carboniferous period : even assuming that the very few supposed cycadean leaves of Palaeozoic age are correctly ^referred to in this class, there is no evidence of the existence of cycadean plants like those of the Jurassic era previous to the early days of the Mesozoic period. Finally, recent research has shown that the great majority at least of the supposed types of Carboniferous ferns are founded on impressions of fronds belonging to plants which produced seeds and must be included among gymnosperms. There is no satisfactory reason for believing that any of the Jurassic Conifers, or that such genera as Ginkgo and Baiera had been produced at this stage in the development of the plant-world, when the greater part of the northern hemisphere was overspread by the forests from which our coal-seams were derived." A. C. S. Plants from the Middle and Lower Estuarine Series. Bryophyta. Localities. Marcbantites ereotus (Leek.) Gristhorpe, Cloughton. Pteridophyta. Equisetales. Equisetites columnaris Brongn Gristhorpe, Cloughton, Peak, Whitby, Carlton, Marske. „ beani (Bunb.) Marske, Roseberry (Topping), Whitby. Neocalamites sp. Whitby. Lycopodiales. Lycopodites falcatus L.