SS eee Steet IN te csp roré ie nate see TETAS Or Zod Pepez ‘S10 Cornell University Library Ithaca, Nem York BOUGHT WITH THE INCOME OF THE SAGE ENDOWMENT FUND THE GIFT OF HENRY W. SAGE 1891 Cornell Universit The geology of the neighbourhood of Edin vi CHAPTER V. PAGE Upper OLD RED SANDSTONE . : : . 42 Liberton to Craigmillar and Salisbury Craigs é . . 48 Blackford Hill to Craiglockhart Station . j ; . 44 CHAPTER VI. THE CARBONIFEROUS SYSTEM . . é F ; . 47 History of Investigation . : ; é . . AT CHAPTER VII. CALCIFEROUS SANDSTONE SERIES OF THE EDINBURGH, GRANTON AND CoLinTon District . si f 3 ‘i : . 54 Cementstone Group ~ : ‘ : . 54 Volcanic Rocks of ‘Arthur’s s Seat é 5 . . 57 o ,, of Calton Hill A : 3 : . 73 , of Craiglockhart . F : . 74 The Oil-Shale Group 7 ‘ : . : . 7 CHAPTER VIII. CALCIFEROUS SANDSTONE SERIES OF THE QUEENSFERRY, BROXBURN AND WEST CALDER DIstTRICT ; é ‘ . 80 Cementstone Group ; : i ‘ ‘ . 82 The Oil-Shale Group ; 85 Area South of Mid-Calder hetrest the ‘Murieston and Calder Faults : . 86 River Almond Section from Clifton Hall to Almondell . 87 Pumpherston Shale-field : ; . 89 West Calder Shale-field ‘ 91 Shore Section between Whitehouse Point and Midhope \ Burn : 95 Drumerosshall to Wester Ochiltree ‘ ‘ ‘ . lol Wester Ochiltree and Kingscavil District . ; . 10] Blackness and Kingsfield Area . : : - 102 CHAPTER IX.” CaRBoniIFEROUS Limestone SERIES oF THE CoBBINSHAW, BaTH- GATE, Bo’NESS AND CHARLESTOWN DIstTRIcT ‘ : . 104 Lower Limestone Group . ‘ ‘ ; . 105 Cobbinshaw and Addiewell Area . : 7 . 105 Bathgate Area : : : : . 107 Tartraven to Hillhouse z 3 : ‘ . lll Hillhouse to Linlithgow ‘ : 3 ‘ . 112 Linlithgow to Carriden ‘ j . . 113 Charlestown and Limekilns (Fife) 5 : ‘ . 116 vil Bo’ness aud Bathgate Coal Group Woodmuir and Foulshiels Area South of Breich Water Bathgate Area ‘ : The Knock to Cocklerue (Sheet 31) Cocklerue to Linlithgow (Sheet 31) . Linlithgow to Bo’ness (Sheet 31 in part) Upper Limestone Group . Woodmuir and Foulshiels Area (Sheet 31) The Bathgate Area (Sheet 31) Hilderston to Cocklerue (Sheet 31) Cocklerue to Linlithgow (Sheet 31) Linlithgow to Bo’ness (Sheet 31) s Carboniferous Volcanic Rocks of the Bathgate, Linlithgow and Bo’ness District . Bathgate to Cocklerue (Sheet 31 in part) : Cocklerue and ee to Tenens (Sheet 31 in part) Linlithgow to Bo'ness Volcanic Necks West of Edinburgh and the Pentland Hills CHAPTER X. CaLcIFEROUS SANDSTONE SERIES OF THE Mrp-LotHian Basin Oil-Shale Group. Portobello, Niddrie and Gilmerton Keren Area between Straiton and Glencorse Burn . Penicuik, Carlops and Rutherford Area Borthwick, Middleton and Tyne Water CHAPTER XI. CARBONIFEROUS LIMESTONE SERIES OF TEE Mip-Lotuian Basin Lower Limestone Group . : Joppa, Niddrie and Gilmerton Area . Loanhead, Bilston Burn and Mauricewood Area Area between Penicuik and Carlops Middleton, Esperston, Temple and Mount Lothian Area Tyne Water and Gore Water Area. : The Roman Camp, Fordel and Cousland Area Area North of Crossgatehall . The Edge Coal Group Niddrie, Portobello and Gilmerton Fields Loanhead and Mauricewood Fields . Penicuik Field Temple Field . : % The Gorebridge, Newtongrange and Cowden Fields . : Coal-field East. of Gorebridge and of the Roman eee Ridge ; Carberry and Prestongrange Field The Upper Limestone Group : Portobello, Niddrie and Gilmerton Area Loanhead, Bilston Burn and Mauricewood Area Penicuik ‘Area ‘ Arniston Mains, Gorebridge and Smeaton Area PAGB 117 118 121 127 127 136 136 137 139 139 141 144 145 149 150 156 159 161 163 171 174 176 176 1717 180 184 186 190 191 194 194 200 212 217 225 227 231 232 235 237 239 ‘SCUVNOU] “LG NOU HONAVY S.NOI'T GHL ANV Ivdg SYoOHLIy *(MODIMSILNON GT) "TL OLLVId MEMOIRS OF THE GEOLOGICAL SURVEY, SCOTLAND. THE GEOLOGY OF THE NEIGHBOURHOOD OF EDINBURGH. (SHEET 32, WITH PART OF 31.) SECOND EDITION. By B. N. PHACH, LL.D., F.R.S.; C. T. CLOUGH, M.A.; L. W. HINXMAN, B.A.; tHe Late J. S. GRANT WILSON; C. B. CRAMPTON, M.B., C.M.; H. B. MAUFE, B.A.; anp EH. B. BAILEY, B.A.; WITH CONTRIBUTIONS BY J. HORNE, LLD., F.B.8.; W. GIBSON, D.8c.; E. M. ANDERSON, M.A., B.Sc.; anp G. W. GRABHAM, M.A, AND PETROLOGICAL CHAPTERS BY J. 8. FLETT, M.A., D.Sc. PUBLISHED BY ORDER OF THE LORDS COMMISSIONERS OF HIS MAJESTY’S TREASURY. EDINBURGH: PRINTED FOR HIS MAJESTY’S STATIONERY OFFICE By MORRISON & GIBB LIMITED At TANFIELD. And to be purchased from E. STANFORD, 12, 13, and 14 Lone Acre, Lonpon; W. & A. K. JOHNSTON LIMITED, 2 St. Anprew Square, EpINBURGH; HODGES, FIGGIS, & Co., Grarron Strext, DuBLIN. From any Agent for the sale of Ordnance Survey Maps; or through any Bookseller ; from T. FISHER UNWIN, 1 Ape.ent Trrracz, Lonpon, W.C., who is the sole Wholesale Agent to the Trade outside the County,of London. “1910, Price Seven Shallings and Sixpence. EY it : 4. QE abel Yanez. \ato A dqr sie PREFACE. ——_+——— THE present volume forms the second edition of the Memoir on “The Geology of the Neighbourhood of Edinburgh,” which was written by H. H. Howell and (Sir) A. Geikie, and published in 1861, when Sir R. I. Murchison was Director General and (Sir) A. C, Ramsay, Local Director. That Memoir described the geology of the districts included in the one-inch map 32—the first published sheet of the Geological Survey in Scotland—together with a strip of ground, about two miles broad, along the eastern margin of Sheet 31. The present edition deals with the same districts, except a small part of the county of Fife to the east of Inverkeithing, which was described by Sir A. Geikie in the Memoir on “ The Geology of Central and Western Fife and Kinross ” (1900). The development of the oil-shale fields in the Lothians, after the ground had been originally mapped by the Geological Survey, neces- sitated the revision of the shale-bearing areas, which was carried out by Mr. H. M. Cadell between 1884 and 1887. This additional informa- tion was embodied in a second edition of Sheet 32, published in 1892. The results of the revision of the Carboniferous districts, which was begun in 1902 and continued at intervals till 1906, by Messrs. Peach, Clough, Hinxman, Grant Wilson, Gibson, Crampton, Maufe, Bailey, Anderson, and Grabham, are incorporated in this volume. These officers have furnished descriptions of their respective areas. Dr. Peach re-examined a tract embracing the city of Edinburgh and Leith, southwards to Liberton and Colinton, thence along the north-west slope of the Pentland chain to the Cairn Hills. Mr. Clough revised the Coal Measures of the Mid-Lothian basin south of Smeaton and Sheriffhall, together with an area between Crossgatehall and Gorebridge, composed partly of Millstone Grit and partly of the Carboniferous Limestone Series. The eastern part of this basin, from Prestongrange to Crossgatehall was re-examined by Mr. Anderson, and from Cousland to Temple by Dr. Crampton; the southern part from Borthwick by Mount Lothian to Carlops and Penicuik, by Mr. Hinxman ; the western portion from Penicuik to Gilmerton, by the late Mr. Grant Wilson; and the north-western area from Gilmerton to Portobello and Musselburgh, by Messrs. Gibson and Bailey. West of Edinburgh and the Pentland Hills, the Carboniferous districts were thus apportioned: to Dr. Crampton was assigned a triangular area stretching from Newhaven and Cramond in the north to the village of Currie in the south; to Mr. Grant Wilson, the fertile tract comprising the oil-shale fields extending westwards to Blackness, Dechmont, and Leven; to Mr. Bailey, the ground surrounding Blackburn and Bathgate; to Mr. Maufe, the central portion of the volcanic area of the Bathgate Hills; to Mr. Grabham the part between Carribber and Linlithgow; and to Mr. Clough the ml iv region between Linlithgow and the Forth. North of the Firth of Forth, Mr. Maufe revised that part of the county of Fife lying between Crombie Point and Inverkeithing. In 1906 an economic Memoir dealing exclusively with the Oil- shales of the Lothians was published by the Geological Survey, in which the geology of the various shale-fields was described in detail. Only a few typical sections illustrating the structure of the shale region are here reproduced from that Memoir. The descriptions of the Carboniferous districts have been almost wholly rewritten owing to the acquisition of fuller information, but in some cases the accounts by H. H. Howell and Sir A. Geikie have been retained. The Lower Old Red Sandstone volcanic rocks of the Braid Hills were revised by Dr. Peach, and of the Pentland Hills by Mr. Cunningham Craig when attached to the staff of the Geological Survey, and afterwards in part by Dr. Peach, but the account of the stratigraphy of that formation has been furnished by Dr. Peach. The description of the isolated areas of Silurian rocks in Sheet 32 by Dr. Peach and Dr. Horne has been reproduced from the Memeir on “ The Silurian Rocks of Scotland,” published in 1899. No systematic re-examination of the glacial deposits was carried out during the revision of the Carboniferous districts, but a brief outline is given of the history of that period based partly on the work of the Geological Survey and partly on the researches of other observers. Dr. Flett has contributed the chapters on the Petrography of the Volcanic Rocks of the Pentland Hills and of the Carboniferous Volcanic Rocks of the Edinburgh and Linlithgow district. The rock analyses have been made by Dr. Pollard and Mr. Radley. The lists of fossils in the paleontological part of the Appendix have been compiled by Mr. D. Tait. These lists are based on determinations made by R. Etheridge, junr., Dr. Peach, Dr. Crampton, and Dr. Lee, with the assistance of Messrs. H. B. Brady, T. Rupert Jones, J. W. Kirkby, Dr. Traquair, Dr. Kidston, Dr. Wheelton Hind, and Dr. Foord. Dr. Lee has furnished notes on the Distribution of Life in the Lower Carboniferous Rocks of Sheet 32. The bibliographical part of the Appendix, containing a list of works referring to the geology of the districts included in this memoir, was prepared by Mr. D. Tait. Special thanks are due to those associated with the mining industry of Mid and West Lothian for information supplied when the revision was in progress, and to Mr. Reid of Messrs. Leslie and Reid, C.E., for notes regarding the water supply of Edinburgh and the surrounding district. The photographs reproduced in Plates I. toIV., VI. and VIII., were taken by Mr. R. Lunn, and the micro-photographs in Plates IX. to XII. by Mr. T. C. Hall. The photograph of the east and west dyke in Inchcolm (Plate V.) has been kindly supplied by Mr. A. G. Stenhouse. The Memoir has been edited by Dr. Horne. J. J. H. TEALL, Director. GEOLOGICAL SURVEY OFFICE, 28 JeRMyN STREET, LONDON. 17th November 1910. CONTENTS. ——_+——_ CHAPTER I. PAGE IntRopucTion 1 Area and Physical Features 1 Formations and Rock Groups. : 5 : 3 General Sketch of the Geology of the District . 4 Description of Horizontal Section in Colour-printed Edition of Sheet 32 8 CHAPTER II. Tue Siturian Rocks . ‘ ; : : . 10 Llandeilo-Caradoc : : : ; . 10 Wenlock, Ludlow and Downtonian 10 i. Tnlier extending from the Lyne Water by the North Esk to the Green Law ’ Il ii. The Loganlee and Craigenterrie Inlier . . IT ii. Bavelaw Castle Inlier : ‘ ; ‘ . 18 CHAPTER III. Lower OLD Rep SANDSTONE . ; . 19 (a) Basement Conglomerates ‘and Sandstones ‘ . 20 (b) Bonally Group of Basalts and Basic Andesites . . 22 (c) Bell’s Hill and Howden Burn Group of Rhyolites . 23 (d) Allermuir Group of Basic Andesites and Basalts . 28 (e) Caerketton Group of Rhyolitic Lavas and Tuffs 24 (f) Woodhouselee and Braid Hills Group of Acid Andesites and. Trachytes 24 (g) Carnethy and Hillend Group of Basalts and Basic Andesites : 25 Volcanic Vents and Intrusive Tgneous Rocks of Lower Old Red Sandstone Age . : ; . ‘ . 26 CHAPTER IV. PETROGRAPHY OF THE VOLCANIC Rocks oF THE PENTLAND Hints . 29 The Basalts : : P é ; ; . 3i Andesites . P . 33 Biotite and Hornblende Andesites and Trachytes ; . 35 The Braid Hills Rocks : : : . 36 Rhyolitic and Felsitic Lavas 8 ‘ , : . 38 Intrusive Acid Rocks—Microgranites ; ‘ . 40 v vi CHAPTER V. PAGE Uprer OLD RED SanDsTONE . : : . 42 Liberton to Craigmillar and Salisbury Craigs ; ‘ . 43 Blackford Hill to Craiglockhart Station . : ; . 44 CHAPTER VI. Tur CARBONIFEROUS SYSTEM . : : 5 : . AT History of Investigation . . ‘ : . AT CHAPTER VII. CALCIFEROUS SANDSTONE SERIES OF THE EDINBURGH, GRANTON AND CoLIntTon DIstRIcT . ‘ z 5 2 i . 54 Cementstone Group ‘ : : j . 54 Volcanic Rocks of ‘Arthur’s sSeat . P , : . 57 4 ;, of Calton Hill : ss ‘ : o. ES » Of Craiglockhart . ‘ r j . 74 The Oil-Shale Group ‘ ‘ 3 ‘ i . 7 CHAPTER VIII. CALCIFEROUS SANDSTONE SERIES OF THE QUEENSFERRY, BROXBURN AND WEST CALDER DistTRIcT ; : ‘ % . 80 Cementstone Group 3 ; ‘ : . . 82 The Oil-Shale Group : 85 Area South of Mid-Calder “between the “‘Murieston and Calder Faults ‘ 86 River Almond Section from Clifton Hall to Almondell . 87 Pumpherston Shale-field é é . 89 West Calder Shale-field ; 91 Shore Section between Whitehouse Point and Midhope i Burn 5 . 95 Dru merosshall to Wester Ochiltree ‘ 7 ‘ . 101 Wester Ochiltree and Kingscavil District . ; . 101 Blackness and Kingsfield Area ‘ 3 3 . 102 CHAPTER IX. CARBONIFEROUS LIMESTONE SERIES OF THE CoBBINSHAW, BatH- GATE, Bo’NESS AND CHARLESTOWN District _ 2 . 104 Lower Limestone Group . : : : . 105 Cobbinshaw and Addiewell eas ‘ ‘ : . 105 Bathgate Area ‘ ; : : . 107 Tartraven to Hillhouse ; 7 ‘ 3 . li Hillhouse to Linithgow ‘ : i . » 112 Linlithgow to Carriden ; : ‘ : . 118 Charlestown and Limekilns (Fife). ‘ . . 116 vu Bo’ness aud Bathgate Coal Group Woodmuir and Foulshiels Area South of Breich Water Bathgate Area The Knock to Cocklerue (Sheet 31) . Cocklerue to Linlithgow (Sheet 31) Linlithgow to Bo’ness (Sheet 31 in part) Upper Limestone Group . Woodmuir and Foulshiels Area (Sheet 31) The Bathgate Area (Sheet 31) Hilderston to Cocklerue (Sheet 31) Cocklerue to Linlithgow (Sheet 31) Linlithgow to Bo’ness (Sheet 31) : Carboniferous Volcanic Rocks of the Bathgate, Linlithgow and Bo’ness District . Bathgate to Cocklerue (Sheet 31 in part) Cocklerue and ee. to eee (sheet 31 in part) se oathioei to Bo’ness Volcanic Necks West of Edinburgh and the Pentland Hills CHAPTER X. CALCIFEROUS SANDSTONE SERIES OF THE Mrp-LotHian Basin Oil-Shale Group. Portobello, Niddrie andl Gilmerton Aes, Area between Straiton and Glencorse Burn . Penicuik, Carlops and Rutherford Area Borthwick, Middleton and Tyne Water CHAPTER XI. CaRBoniFEROUS LimEsTONE SERIES OF THE Mip-Loturan Basin Lower Limestone Group. : Joppa, Niddrie and Gilmerton Area . Loanhead, Bilston Burn and Mauricewood Area Area between Penicuik and Carlops . Middleton, Esperston, Temple and Mount Lothian Area Tyne Water and Gore Water Area. The Roman Camp, Fordel and Cousland Area Area North of Crossgatehall . The Edge Coal Group : Niddrie, Portobello and Gilmerton Fields Loanhead and Mauricewood Fields . Penicuik Field Temple Field . z The Gorebridge, Newtongrange and Cowden Fields . Coal-field East of Gorebridge and of the Roman ey Ridge : ‘ Carberry and Prestongrange Field The Upper Limestone Group , Portobello, Niddrie and Gilmerton Area Loanhead, Bilston Burn and Mauricewood Area Penicuik Area Arniston Mains, Gorebridge and Smeaton Area PAGE 117 118 127 127 136 136 137 139 139 141 144 145 149 150 156 159 161 161 163 171 174 176 176 177 180 184 186 190 194 194 200 212 216 217 225 231 232 235 237 239 vill CHAPTER XII. Tue Rostin Sanpstone Serirs (MILLSTONE Grit) or THE Mip- LotHian Basin : Portobello and Niddrie Area Gilmerton and Roslin Area Penicuik Area Carrington, Newtongrange and Smeaton Area Musselburgh Area . CHAPTER XIII. Tur Coat Measures or THE Mip-Loruian Basin i. Lower Coal Measures. Joppa, New Craighall, Musselburgh and Woolmet Fields Smeaton, Cowpits and Pinkie Fields . Coal-field South of the Sheriffhall Fault Penicuik and Auchencorth Outliers . ii. Middle Coal Measures (?) CHAPTER XIV. Igneous Rocks INTRUSIVE IN CARBONIFEROUS STRATA Earlier Group of Intrusive Rocks . Olivine Dolerite, Teschenite, Picrite . Later Group of Intrusive Rocks Quartz Dolerite Sills . East and West Dykes CHAPTER XV. Tue PETROGRAPHY OF THE CARBONIFEROUS VoLcANIC Rocks or ;. THE EDINBURGH AND LINLITHGOW Districts The Non-Porphyritic, Granular-Crystalline Dolerites (Diabases), Teschenites and Essexites i. Olivine Dolerites, Teschenites (Analcite Olivine Dolerites) and Essexites (with the Picrites) ii. Quartz Dolerites (Quartz Diabases) Marginal Phenomena of the Dolerite Sills White Traps Contact Alteration of the Sedimentary Rocks by the Intrusive Sills. The Olivine Basalts and Porphyritic Olivine Dolerites i. Basalts of the Lion’s Haunch Type u. A. Basalts of the Dalmeny Type . ii. B. The Hillhouse Type : ii. C. Analcite Basalts iii. A. The Jedburgh Type ii. B. The Kilsyth Type ii. C. The Gallaston Type Mugearites : PAGE 244. 245 246 249 249 252 254 256 256 260 265 271 272 275 276 276 282 282 286 287 289 289 308 311 313 316 317 319 320 320 321 321 32] 322 1x CHAPTER XVI. GLACIAL AND Recent Deprosits i. Glacial Deposits Striated Rock- Surfaces Boulder Clay . Erratic Blocks Sands and Gravels Ancient Lakes ii. Raised Beaches ii. Alluvial Terraces CHAPTER XVII. Economics Coal and Treristorie Brick Clay and Fireclay Oil-Shale . Silver Lead and Nickel Ores Limestone Building Stone. Paving Material and Road Metal . Water Supply . APPENDIX. -——_4+——_ Parr I.—PALHONTOLOGICAL . Notes on the Distribution of Life i in the Tower Carbon- iferous Rocks (Sheet 32), by Dr. Ler A. List of Localities for Carboniferous Fossils in Shee 32, the East Part of Sheet 31, and the Northern ee of Sheet 24 . B. General List of Carboniferous Fossils arranged in their Systematic Order . C. Lists of Post-Tertiary Fossils Part IJ.—BIBLIOGRAPHICAL . List of Works referring to the Geology of the Area included in the Memoir, compiled by Mr. D. Tarr . 3 InpeEx prepared by Mr. E. M. ANDERSON PAGH 324 326 326 328 329 331 332 335 336 337 337 348 350 352 353 356 359 361 369 369 373 384 406 413 413 ” 0 8. 9. 10. ll. 12. 13. 14. 1b. 16. 17. 18. LIST OF ILLUSTRATIONS. pe FIGURES IN TEXT. . Section across the eee Silurian Rocks of the Pentland Hills . Generalised Vertical Sclian of the Carboniferous Strata of Mid and West Lothian . Section from the Castle Rock across Salisbury Craig a Whinny Hill to Parsons Green . Section across Arthur’s Seat from the Meadows to nae showing the position of the two volcanic necks . . Junction of Lion’s Haunch Basalt with massive agglomerate, Loch Craig lava, tufis, and sediments in Queen’s Drive . Section across the Calton Hill, Bainburgh . Section from Nether Dechmont and Enigentle to Illieston and the River Almond Section from Addiewell Bridge to Limefield Mains Section along the Shore from epee Burn to Whitshouse Point Generalised Section of the Bo’ness and Bathgat Coal Group near Bo’ness General Section of the Volcanic Rages of the Bathgate Hills Section in Kast Gaia Kirkton Section of Burdiehouse and Straiton Shale- field Comparative Sections of Strata below Gilmerton Limestone in Burdiehouse Burn and in Bilston Burn Map showing the sequence of Carboniferous Strata in Bilston Burn : Section of Calciferous Sandstone and Lower Limestone Group in Amazondean Burn and in Habbie’s Howe, Carlops . Diagram Section showing inclinations of the seams in No. 10 Pit, Niddrie Colliery Section from Mauricewood House to Loanstone, as folding of the Carboniferous Limestone Series 19. Map showing the intrusive sheet of ube Dolerite at Ravencraig x PAGE 14 52 55 64 68 73 88 92 96 128 145 147 163 170 181 184 195 201 285 PLATE Pa 2 I. II. III, IV. VI. VII. VIII. ix. 2? XI. EP 29 xi PLATES. Arthur’s Seat and the Lion’s Haunch from 8&t. Leonards . : . Frontispiece The Pentland Hills from eee Raa looking south-west : 3 . Facing p. 24 Intrusive Sill of Teschenite, pps Old Red Sand- stone in the Foreground, Salisbury Craigs, Arthur’s Seat : ; . Facing p. 56 Columnar Basalt within the Lion’s Haunch Vent. Samson’s Ribs, Arthur’s Seat. . Facing p. 67 . East and West Dyke of Quartz-Dolerite (on right) cutting Sill of Picrite (on left) intrusive in Calciferous Sandstone, Inchcolm Facing p. 280 Quartz-Dolerite intrusive in Calciferous Sandstone, Hound Point, North of Dalmeny Park Facing p. 283 Shore Section at Joppa, Midlothian (folding Plate) Facing p. 245 Transported Mass of Lava of Lower Old Red Sandstone Age resting on Glacial Sands and Gravels, Comiston Sand Pit, near Edinburgh Facing p. 330 PLATES (aé end of Volume). Fies. 1 and 2. Silicified Rhyolite or Trachyte, Camp Hill Quarry, 3 miles West of Penicuik, Pentland Hills. » 93. Quartz Diabase, Quarry on North Side of West Bangour, 34 miles N.E. of Bathgate, Linlithgowshire. » 4. Quartz Hypersthene Diabase, North Queens- ferry. a Quartz Diabase, North Queensferry. Quartz Diabase, Bog Cottage, 1 mile South of Linlithgow. . Edge of Diabase Sill, Hound Point, Dalmeny. . Quarry near Ochiltree Mill, Linlithgow. S wnre . Spotted, Cale-silicate Hornfels near margin of Dolerite-Picrite intrusion, Barnton Railway cutting, near Edinburgh. Fie. 1. Teschenite, Quarry on Queensferry Road, 1 mile E.SE. of South End of Forth Bridge. » 2. Picrite, South Side of Railway cutting, Barnton, near Edinburgh. » 3. Olivine Basalt (Craiglockhart type), Craig- lockhart, near Edinburgh. xil Prats XI. Fig. 4. Olivine Basalt (Jedburgh type), Whinny Hill, Arthur’s Seat, 100 yards South-east of St. Margaret’s Loch. 5. Mugearite, Quarry on the roadside 1} miles S.SE. of Kirknewton. ts » 3, 6. Vein of fine Porpbyritic Basalt penetrating the Sandstones of Salisbury Craigs, Arthur’s ” a » Seat. - XII. Fie. 1. Olivine Basalt, Lion’s Haunch, Arthur’s Seat. 3 3 ,», 2 Olivine Basalt, Dunsapie, Arthur’s Seat. . Olivine Basalt, 300 yards SS.E. of St. Anthony’s Chapel, Arthur’s Seat. es 5 » 4. Olivine Basalt, Railway cutting at back of Engine Shed, St. Margaret’s Works, near » S . S oo Edinburgh. a5 re » 5. Olivine Basalt, small Quarry at the Powder Magazine, Oil Works, Wester Dalmeny. - 4 » 6. Olivine Basalt, Hillhouse Quarry, 2 miles South of Linlithgow. MAP (at end of Volume). Geological Map of Arthur’s Seat and the Calton Hill on the scale of six inches to one mile. Explanation oF Scortish Minine Terms. Blaes, argillaceous shale ; Daugh, coaly fireclay ; Fakes, shaly sand- stone or sandy shale; Kingle (sometimes called Kennel), very hard or indurated sandstone; Sclit or Sclutt, coaly blaes or slaty coal. GEOLOGY OF THE NEIGHBOURHOOD OF EDINBURGH. CHAPTER I. INTRODUCTION. AREA, PHYSICAL FEATURES, AND GENERAL DISTRIBUTION OF THE Rocks. TuE district described in this memoir includes the area within the limits of Sheet 32 of the one-inch map of Scotland, and, for the sake of completeness, a narrow strip about two miles in width along the eastern margin of the adjoining map 31. It thus comprises the greater parts of the counties of Edinburgh and Linlithgow, with portions of Haddington, Peebles, Lanark and Fife. Most of the district described lies to the south of the Firth of Forth and contains the valuable coal-field of Mid-Lothian and almost the whole of the oil- shale fields of the Lothians. Hence it embraces one of those rich mineral tracts in the Midland Valley of Scotland which have contributed so much to the development of the country. The physical features of the district present that union of level cultivated plains with undulating and hilly ground, varied by the frequent occurrence of abrupt solitary crags, which forms the characteristic scenery of central Scotland. It is divided into two well-marked portions by the chain of the Pentland Hills, which traverses its centre from south-west to north-east and rises to a height of 1898 ft. above the sea. The eastern area consists of a broad plain, which, from the foot of the hills, stretches eastwards into Haddingtonshire and southward until it abuts against the slopes of the Moorfoots. With the exception of the minor undulations incident to a drift-covered district, the continuity of this plain is unbroken except by the long ridge * of the Roman Camp Hill east of Dalkeith, which, beginning near the sea at Prestonpans and running south-west parallel to the Pentlands, divides the plain into two, the western portion being known as the Mid-Lothian Coal-Field, while that to the east includes the coal-basin of East Lothian situated in Sheet 33. The margin of the Firth of Forth truncates both coal- * The south-west part of this ridge is generally termed the Roman Camp Hill, but this name does not appear in the new edition of Sheet 32. The site of the sup- posed Roman Camp is indicated by the word Fort in this edition, I 2 Introduction. fields, the coal seams passing under the sea and reappearing on the opposite shores of Fife. The great central ridge of the district may be regarded as com- mencing at the Braid Hills, whence it stretches south-west through the Pentland Hills till it merges into the uplands of Peebles and Lanark. The district to the west of this chain of hills comprises nearly two-thirds of Sheet 32, and presents a physical contour con- siderably different from that on the east side. With the exception of the broad plain which extends for seven miles to the west of Edinburgh, this western division contains few level spaces of any extent. Throughout the greater part the surface undulates in ridges, of which the general direction may be taken as east and west, but their continuity seldom remains persistent, more frequently they coalesce or branch out into a new series, the determining cause being in many cases some prominent crag or hill of igneous material. A conspicuous feature along the western margin of the district (Sheet 31) is the ridge of hilly ground running in a north and south direction from Bathgate towards Linlithgow, which, as will presently be shown, is due to the geological structure of the region. - The part of the county of Fife included in Sheet 32 displays physical features characteristic of a Carboniferous district with intrusive igneous rocks, partly covered with superficial deposits. Before describing the geology of the area in detail, it will be well to give a brief outline of the general distribution of the rocks, the more especially as such an outline will illustrate how closely con- nected are the geology and the physical geography of a country. The Pentland Hills, forming the backbone of the region, consist fundamentally of highly inclined Upper Silurian shales and grits, covered unconformably by coarse conglomerates and sandstones, and voleanic rocks belonging to the Lower Old Red Sandstone formation. At the north-east end of the chain, and in various places along its north-west side, sandstones and cornstones belonging to the Upper Old Red Sandstone rest unconformably on the older rocks and pass upwards into the basal beds of the Carboniferous system. The rocks entering into the structure of the Pentland Hills form an anticlinal axis over which the Carboniferous rocks are folded, though, owing to large parallel faults, the regularity of this anticline has been materially disturbed. Along their south-east margin the Pentland Hills are bounded by a great fault, and the broad plain farther south-east consists entirely of Carboniferous rocks. They form asynclinal trough, the west side of which flanks the Pentland Hills, while the eastern swells up into the Roman Camp ridge. That ridge is an anticlinal axis formed by the lowest group of the Carboniferous Limestone series, which, rising from beneath the Mid-Lothian Coal-field,sinks eastwards below the coal- basin of East Lothian, the latter being included chiefly in Sheet 33. The district between the north end of the Braid Hills and the sea consists of Upper Old Red Sandstone and Calciferous Sandstone strata, the latter associated with numerous interbedded and intrusive igneous rocks, which give rise to prominent features in Arthur's Seat, Calton Hill and the Castle Rock. West of the Pentland Hills the Calciferous Sandstone strata, com- Formations and Groups of Rock. 3 prising the productive oil-shale measures, extend in a great series of anticlines and synclines varied everywhere by detached masses of igneous rock, chiefly of an intrusive character. In spite of frequent repetitions the general dip is westerly, and near the western margin of one-inch Sheet 32 the Carboniferous Limestone series again appears with a middle coal-bearing group, which composes the important Bo'ness and Bathgate coal-fields. In this western area all three subdivisions of the Carboniferous Limestone series are associated with sheets of interbedded and intrusive dolerite and volcanic ash which are absent from this series farther east in the Mid-Lothian coal-basin. The more prominent hills over this western area consist almost uniformly of igneous rock, and the narrow valleys which divide them frequently owe their origin to the denudation of inter- calated shales and sandstones, or to lines of fault along which the denuding agents have acted.* FORMATIONS AND Rock GROUPS. The geological formations occurring within the area are repre- sented in stratigraphical order in the following table with the symbols used in the map :— Peat in hollows occupying the sites of old lakes and on Pleisto- hill slopes .. ity i se cene and { River Terraces and fresh-water alluvia Recent. | Raised Beaches and marine alluvia Glacial or Fluvio-glacial sands apres and brick clays .. Boulder Clay .. ‘ a [Fst Sand .. Middle Coal Measures ? Red sananeond ee a a i ‘a; | Upper. {ewer Coal Measures : 3 os Upper Roslin Sandstone Series or Millstone Grit 3 at % 5 Lower Roslin Sandstone Series or Millstone Grit oO | Lower. {cationtero Limestone Series .. a a d? Calciferous Sandstone Series sis ss af wa. db 3 et Z & J Upper. Red sandstones and cornstones .. is 2 ae 08 se £ | Lower. Red sandstones and conglomerates . 2 De se et ° ne Downtonian .. na ae ae ot ee. bf 28 { Uppe ( Wenlock and Ludlow es i “s ed .. be m'~ \ Lower. Llandeilo-Caradoc .. - 3 sh be .. b?,3 IGNEOUS ROCKS. A. Contemporaneous with the formations among which they lie. In Carboni- (Lava flows of Basalt or Dolerite of the Gallaston and ferous Lime- Dalmeny types .. 6 a6 aif as .. wBd? ‘stone Series. (Basaltic Tuff.. 6 “i as via oe .. BZd? Lava flows of Basalt of Gallaston and Dalmeny types .. vBd? In Calciferous | ,, + », Craiglockhart type eke .. xBd! Sandstone 39 a » Dunsapie type aie a .. yBd! Series. 5 eee af ak wh .. oWd! Basaltic Tuff .. i ae we uh .. BZd! * The foregoing description with some alterations has been taken from the first chapter of the “‘ Geology of the Neighbourhood of Edinburgh,” Mem. Geol, Sur., 1861, written by Sir A, Geikie. 4 Introduction. Lava flows of Basalt.. .. Bel 5 » Augite and Hypersthene Andesite | .. pAct In Lower 55 », Hornblende and Mica Andesite .. .. bAct Old Red 3 », Trachyte os a on Thee Sandstone. 95 5, Rhyolite ae Sire, hs bs .. Rel Andesitic Tuff a a6 _ sa i .. AZct Rhyolitic Tuff = 3 - es 44 .. RZel B. Intrusive in the formations among which they lie. Dolerite of uncertain character and age .. ia D Permo- Quartz Dolerites in sheets, and dykes with east anil Carboniferous, { west trend . a es a ag og -» qD Picrite ee és A . %U Olivine Dolerite and Teschenite .. 2 oe .. tD Basalt and Dolerite of Hillhouse type .. Ne .» uD Lower * i Dalmeny type... ea .- vD Carboni- 5 ne Craiglockhart type ae xD ferous. Lion’s Haunch or Pumps type yD Basaltic Tuffsin Necks .. #3 . BV Agglomerate ,, ,, a ss oe VW Necks of Lower Old Red Sandstane age ae a .» Vet Pre-Carboni- | Lamprophyre is oa se . FL ferous. Diorite Po a aa = > H Felsite and Microgranite a Pe a 8 fon GENERAL SKETCH OF THE GEOLOGY OF THE DISTRICT. The oldest rocks represented in this region belong to the Silurian system, and range from Llandeilo to Downtonian time. They form the floor on which the younger Paleozoic strata repose with a marked unconformability, and appear chiefly as inliers in the Pent- land Hills, where the basal conglomerates of the Lower Old Red Sandstone are composed mainly of greywacke pebbles derived from the old Silurian tableland. The dominant types of strata in the Pentland Hills that belong to the Wenlock and Ludlow divisions of the system, consist of pebbly grits, greywackes, concretionary sandstones, shales and mudstones which yield a prolific fauna of brachiopods, lamellibranchs and gas- teropods. A marked change in the phase of sedimentation is presented by the Downtonian rocks which comprise red and chocolate-coloured sandstones of Lower Old Red Sandstone type, with red and green mudstones yielding remains of the Downtonian fish fauna of Lanark- shire. The researches of Messrs. Henderson and Brown proved that these red sandstones, which were at first regarded by the Geological Survey as a conformable portion of the Lower Old Red Sandstone, are an integral part of the Silurian succession—a conclusion which was confirmed in the course of the re-examination of the ground in 1896. Towards the close of Downtonian time the Silurian strata were subjected to great lateral compression and were thrown into a series of folds, the axes of which run in a north-east and south-west direc- tion parallel to the major axis of the Silurian tableland. It is inter- esting to observe that some of the graptolite-bearing bands of Wenlock age, which occur near the North Esk Reservoir, have been found at Habbie’s Howe in the heart of the Pentland Hills, and at Hare Hill on the north slope of that chain, thus showing that the Wenlock, General Sketch of the Geology of the District. 5 Ludlow and Downtonian rocks must together have been folded and extensively denuded before the outburst of volcanic activity in Lower Old Red Sandstone time. The rocks belonging to the lower division of the Old Red Sand- stone, as already indicated, are prominently developed in the Pentland Hills. The basal members consist of conglomerates and sandstones which rest on the various zones of the Upper Silurian formation from the Downtonian group to the Wenlock shales and grits. But the characteristic feature is the great succession of volcanic rocks, ranging from basalts and basic andesites through acid andesites and trachytes to rhyolites, which have become familiar to geologists through the descriptions of Charles Maclaren and Sir A. Geikie. The acid ejections, however, do not form the highest members of the sequence but are intercalated with basalts and basic andesites. Of special interest is the result of the petrographical examination of the decom- posed claystones of the Braid Hills by Dr. Flett, who regards them as trachytes (Chap. IV.). The lavas and tuffs are accompanied by intrusive igneous materials, comprising diorite, microgranite and felsite, while in the northern part of the chain remnants of small voleanic orifices are to be found. Towards the close of Lower Old Red Sandstone time crustal movements again supervened, whereby the volcanic rocks were folded along an axial line trending north-east and south-west, and were subjected to prolonged denudation. It is highly probable that some of the faults now traversing these rocks may have been developed during these movements. During this interval of time, represented elsewhere by the Middle Old Red Sandstone, the volcanic series was locally removed and the underlying Silurian rocks were laid bare. Hence we find the basal beds of the Upper Old Red Sandstone overstepping each member of the lower division together with its igneous intrusions until they rest on the Upper Silurian strata. The type of sedimentation characteristic of the Upper Old Red Sandstone in other parts of Scotland is to be found in the neigh- bourhood of Edinburgh and on the flanks of the Pentland Hills, where the strata consist of reddish grey grits, sandstones, marls and cornstones. The discovery of fish remains, determined by Dr. Traquair to be fragments of Holoptychius nobilissimus, in the sandstones of Craigmillar and beneath Salisbury Craigs, furnished conclusive evidence of the age of these sandstones, which in the previous editions of Sheet 32 were grouped with the Carboniferous formation. This discovery is a striking confirmation of the conclusions of My. J. G. Goodchild,* who previously suggested this correlation on the ground of the lithological characters of the strata, and especially of the cornstone associated with the sandstone of Salisbury Craigs. The Upper Old Red Sandstone passes conformably upwards into the Carboniferous formation, though there is a marked paleontological break between the two as proved by the researches of Dr. Traquair.+ The Calciferous Sandstone series comprises two subdivisions, the lower one being termed the Cementstone group. As developed in the Edinburgh district it consists of grey, green and red mudstones, * Trans. Edin. Geol. Soc., 1898, vol. viii. pp. 2-9. + “ List of the Fossil Dipnoi and Ganoids of Fife and the Lothians,” Proe. Roy. Soe. Edin., 1890, vol. xvii. p. 385. 6 Introduction, and shales with cementstone bands, occasional sandstones, and rarely some thin seams of dark carbonaceous shale yielding plants, ostracods, and Paleoniscid fish scales of undoubted Carboniferous type. This phase of sedimentation is characteristic of the Ballagan group of the west of Scotland. A marked feature of this period is the outbreak of volcanic activity in the Edinburgh district, the relics of which are typically developed in Arthur’s Seat and the Calton Hill, where there is a succession of lavas ranging from olivine basalts to mugear- ites. The re-examination of Arthur’s Seat by the Geological Survey confirmed the later view of Charles Maclaren and the conclusions of Professor Judd regarding its structure, namely, that the lavas and ashes, together with the central agglomerates and their associated igneous rocks, belong to one period of volcanic activity. Two separate vents have been recognised on the crest of Arthur’s Seat, the larger one showing a slight displacement of the focus of eruption during the history of the volcano. The voleanic horizon of Arthur’s Seat and the Calton Hill has been detected on Corston Hill, north-west of the Pentland Hills, where the lavas may have been ejected from an independent centre. The upper division of the Calciferous Sandstone series comprises a succession of strata of great economic importance, and is known as the Oil-shale group. It contains, in its higher part, beds of coal, usually of inferior quality, and farther down, several valuable seams of oil-shale, interstratified with beds of sandstone, shale, fireclay, marl and estuarine limestones, and underlain by the Wardie Shales and Granton Sandstones. In the last two subdivisions, thin seams of oil- shale have been detected, which yield a small quantity of crude oil and sulphate of ammonia. The Carboniferous Limestone series is roughly divisible into the three following groups :— 3. Upper Limestone group, including three or four thin marine limestones. 2. Edge Coal group or Bo’ness and Bathgate Coal group. 1. Lower Limestone group, including various marine limestones, some of which attain a considerable thickness. These three subdivisions are represented by the same colour on the published map. The basal bed of the Upper Limestone group is the Index or No. 4 Limestone, and the top of the Lower Limestone group is marked by the first band of limestone beneath the series of Edge Coals. Group 2 is of great economic importance, and yields a more valuable series of coals than the Coal Measures proper, so far as this part of Scotland is concerned. It is often termed the Lower Coal Measures by those connected with the Mining Industry. The limits of the Roslin Sandstone series or Millstone Grit nearly coincide with those laid down during the original survey of the district, but, as the base line is now everywhere drawn at the top of the Castlecary (No. 6) Limestone, additional strata are occasionally included. In accordance with the determinations of the plant and fish remains by Dr. Kidston and Dr. Traquair respectively * this group falls paleontologically in two divisions, one being classed with the * «Summary of Progress,’ Mem. Geol. Sur. for 1903, p. 118. General Sketch of the Geology of the District. 7 Upper and the other with the Lower Carboniferous rocks. Although the Millstone Grit is shown by one colour in Sheet 32, a boundary between these two subdivisions has been drawn where the evidence is regarded as conclusive. Next in order come the Lower Coal Measures, with numerous valuable seams of coal, succeeded by red sandstones and marls, which, with some hesitation, have been classed with the Middle Coal Measures. The latter have a striking resemblance to the Upper Barren Measures of Lanarkshire and Fife. The Fifeshire beds have been classed by Dr. Kidston with the Middle Coal Measures of England,* but no sufficient evidence has yet been obtained to prove the age of this subdivision in Mid-Lothian, the few fish and plant remains which have been found being common to the Middle and Lower Coal Measures. One of the striking features of the Carboniferous area described in this memoir is the great development of intrusive igneous rocks, which are now grouped in two divisions according to their age and are expressed by different tints in the new edition of Sheet 32. The older set, consisting of teschenite and olivine dolerite intrusions allied petrologically to the Carboniferous lavas, have been referred to the same general period as the extrusion of the lavas.t No contemporaneous volcanic rocks are known to occur in this area above the Carboniferous Limestone series, and these intrusions are in all probability older than the Millstone Grit. The later set, ~ composed of quartz dolerites, which occur in the form of sills and east and west dykes, are allied in petrological character to the Whin Sill of the North of England They have been proved to be subsequent to the Lower Coal Measures (d®) and are probably of late Carboniferous or Permo-Carboniferous age. : After the close of the Carboniferous period crustal movements again ensued, whereby the Carboniferous strata and the associated igneous rocks were thrown into a series of anticlines and synclines, the axes of which trend generally in a north-east and south-west direction. It is worthy of note that the chain of the Pentland Hills roughly coincides with one of these anticlinal folds whose eastern limb is intersected by the great Pentland fault. This dislocation may be said to form the septum between the arch of the Pentland Hills and the Mid-Lothian coal-basin to the east. It is highly probable that it follows the line of one of the strike faults established in the Lower Old Red Sandstone rocks during their first plication, but the movement during post-Carboniferous time was evidently extremely powerful. The high inclination of the Carboniferous strata along the west side of the Mid-Lothian basin extends eastwards for over a mile from the Pentland fault. The structure is further complicated by the occurrence of minor troughs in some of which the western limb is inverted, as for example at the western edge of the Gilmerton basin, in the Nine Mile Burn *“ { ‘‘ A Sketch of the Geology of Fife and the Lothians, 1839,” 29 30 Volcanic Rocks of Pentland Hills. also are rare, while epidote and zeolites are seldom or never seen. The dark red colour of the screes and weathered outcrops of this series is an unmistakable field-indication of their distribution. II. The most acid rocks become silicified. They change to red hornstone-like or even jaspery masses. Under the microscope their prevalent constituent is secondary quartz, which is intimately mixed with other derivative minerals, such as kaolin. Limonite and hema- tite give them a pale red colour. Calcite is unusual in these rocks, and chlorite is equally rare. Secondary muscovite after the felspar is found mainly in the intrusive acid rocks (Black Hill granite porphyry). The pale colour and flinty character of this group serve perfectly to indicate them in the field. IIT. Decomposition of the third type results in the formation of “claystones.” These are grey, lilac or buff, but their colour depends in large measure on the amount and state of chemical combination of the iron they contain. If hematite is very abundant they are red, if it is very scanty they are creamy or yellow; limonite makes them various shades of brown. They are soft and easily scratched, but are not friable. Often they are spotted with small pale spots, irregularly scattered or grouped in bands. Pseudomorphs after porphyritic felspars are often seen in them, but not usually in abundance, and the rocks are rarely vesicular. Green areas of chlorite after ferromagnesian minerals are seldom to be found in these claystones, and it is a somewhat remarkable fact that while they never show fresh hornblende or augite they occasionally contain scales of black, well-preserved biotite. Secondary quartz rarely appears in these rocks in any quantity, and they are never extensively silicified: this indicates that they do not belong to the acid group. Neither is calcite at all a frequent ingredient of them, which shows that they were originally poor in the more basic soda-lime felspars and pyroxenic minerals. They form, in fact, a group of intermediate rocks, which must have con- sisted principally of felspars belonging to the more acid species of plagioclase and to orthoclase. The microscope shows their composition to be exceedingly simple. In addition to scattered grains of iron oxide, they contain only aggregates of fine scaly ‘kaolin and muscovite after felspar. With very thin sections it is clear that the scaly kaolin and mica are surrounded by a network of another mineral which is colourless, and has a rather high double refraction. This is secondary quartz, the presence of which is explained by the liberation of silica which takes place when the more acid felspars are kaolinised. This quartz forms a sponge, the interstices of which are occupied by kaolin, and when the conditions are favourable it can be established that over small areas the quartz is in optical continuity, so that the structure is a modification of that which is known as “ poikilitic,” but in a secondary aggregate (p. 36). Other evidence regarding the original nature of these rocks will be given later, when the consideration of their least altered repre- sentatives is taken up (p. 36). Chemical analyses of the rocks of the Pentland Hills are of great interest and value. Five are given by Sir Archibald Geikie.* They * “ Ancient Volcanoes of Great Britain,” vol. i. pp. 274 and 278. Basalt. 31 show that, with some modification, the weathered rocks retain toa surprising degree the chemical characteristics of the original lavas, and in cases where mineral degeneration is very far advanced, the bulk composition is not necessarily greatly changed. The elements have entered into new combinations, but have only to a slight extent been carried away and replaced by others of a different nature. In regions like the Pentland Hills where the rocks have so decayed that their original minerals are only to be inferred from the shapes and composition of the pseudomorphs they leave, the petrologist finds that chemical investigation is of the greatest possible value in supporting or negativing the evidence furnished by microscopical examination. THE BasaLts, In the Pentland Hills, olivine basalts occur in considerable numbers, mostly as lava flows, but probably also as intrusions. Most of them are of porphyritic structure; only in a few instances are the rocks ophitic or sub-ophitic. In all cases they are greatly decomposed ; their olivine has been replaced by limonite and hema- tite, which often form dense, opaque pseudomorphs, but at other times have a clear centre composed of calcite, with sometimes an admixture of quartz or of serpentine. In other rocks they consist of dark-brown “iddingsite.” The felspars also are often replaced by calcite and kaolin, and are stained with oxides of iron, but are some- times fairly well preserved, and show the characteristic multiple twinning. Fresh augite has been seen in very few of the slides; it is practically always replaced by calcite, limonite, quartz, and chlorite. It is not always easy to distinguish between the pseudo- morphs after pyroxene and those after olivine; but when the latter mineral is at all abundant, the characteristic outlines of its crystals are always observable, and give a clear indication as to the nature of the original rock. Many of these basalts are vesicular, their steam cavities being filled with chlorite, calcite, iron oxides or various forms of agate and chalcedony. Warklaw Hill Basalts—The rocks of Warklaw Hill and the north-west side of Torduff Reservoir (group 5) are all basaltic, and include some of the most basic lavas of the whole series. They are in a state of advanced decomposition, the felspars being the only minerals which are still preserved, but the pyroxene and olivine can both be identified from the outlines of their pseudomorphs. The olivines were numerous and large, and are represented mostly by calcite and iron oxides, but also by iddingsite and serpentine. The structure is markedly porphyritic, as felspar, augite and olivine all occurred as phenocrysts lying in a finer groundmass, which is now entirely converted into an aggregate of calcite, iron oxides and other secondary products, and is often so ferruginous as to be quite opaque. A few small steam cavities are visible in the sections; they are filled with calcite, chlorite, chalcedony and iron oxides. Both fine-grained and coarse-grained basalts occur in this series, and the former may show pronounced fluxion structure. Sir Archibald Geikie gives an analysis of one of these rocks.* One or two flows of olivine basalt, not unlike those of Warklaw * © Ancient Volcanoes of Great Britain,” vol, i. p. 274, 32 Volcanic Rocks of Pentland Hills. Hill, are found on the Dean Burn above Bonally, intercalated among andesites, and a decomposed sub-ophitic dolerite occurs in the old quarry on the east of Bonally Pond. Along the strike of these rocks there is a knoll in the fields south of Dreghorn Castle consisting of very similar decomposed basalt with many opaque pseudomorphs after olivine. The Allermuir and Loganlee Basalts—The Allermuir group (d) of andesitic and basaltic rocks stretches from the vicinity of Lothian Burn through Swanston, south-west along Allermuir to Loganlee Reservoir. At its base it includes a considerable number of olivine basalts, which repeat all the essential features of those of Warklaw Hill. They are very completely decomposed and are coloured dark brown by abundant secondary oxides of iron, though a few are dark green from the prevalence of chlorite. All contain much olivine and augite, though represented only by pseudomorphs; their felspar is sometimes fairly well preserved but is usually deeply stained with hematite and chlorite, and permeated with calcite. The groundmass is so obscured with secondary deposits as to be undecipherable under the microscope. Vesicles filled with calcite, hematite, chlorite and chalcedony are common in these rocks, though never forming so large a proportion of their bulk as in the augite andesites. A minute description of these rocks is needless owing to their very decomposed state. The collection includes specimens from a small quarry at Swanston Cottage, from the north side of Shearie Knowe, and from the Green Craig. At the roadside on the west of Loganlee Reservoir similar olivine basalts are exposed, both at the north and at the south end of the loch. These rocks have the porphyritic structure usual in lava flows, but ophitic and sub-ophitic varieties (which may be intrusive) occur also at Shearie Knowe and at the north-west corner of Loganlee Reservoir. Several miles to the north-east, in the Mortonhall Golf Course, there is a small ridge of dark olivine dolerite at the east end of the Elf Loch, and a similar rock is found in the old quarry north-west of Meadowhead. Basic rocks recur again among the lavas of the Hillend group (9) and are found also on the east side of Carnethy. The Hillend lavas are dark-red rocks with abundant plagioclase felspar and many pseudomorphs after olivine, but they are not of exactly the same type as those of Warklaw Hill and Loganlee. Their olivine crystals are smaller, less numerous and less conspicuous, and their felspar predominates to such an extent that it is doubtful whether they may not be regarded as olivine-bearing augite andesites. They are separated, however, without difficulty from the augite and hypers- thene andesites (a few of which occur along with them), and it has seemed best to include them among the olivine basalts. In these rocks also the felspar remains in part undecomposed. Iron oxides, calcite and chlorite impregnate them strongly: porphyritic structure is universal, and steam cavities occur frequently, though the rocks are not highly vesicular. The well-known “porphyry” of Carnethy, which carries large pale-green phenocrysts of labradorite in a fine dark-green matrix, has been included among the diabase lavas by Sir A. Geikie, and this seems reasonable in view of the basic character of the rock as Basalts and Andesites. 33 revealed by the analyses cited by this author.* The low percentage of silica (51-16) relegates the rock to the category of basalts. The microscopic sections show little olivine, in small corroded crystals entirely changed to limonite and serpentine (iddingsite). The augite has passed into chlorite, calcite and limonite. Felspar, belonging to a basic variety of labradorite, is the main component of the rock, and occurs in large tabular repeatedly-twinned phenocrysts and numerous small laths of a second generation in the groundmass. The rock contains scattered vesicles filled with chlorite, calcite and chalcedony, and though much decomposed, is* one of the freshest of the basic lavas of the Pentlands. ANDESITES. A considerable variety of andesitic rocks is found in the Pentland Hills, ranging from augite and hypersthene andesites, very dark in colour, to pale biotite and hornblende andesites. The former group is not without difficulty separated from the basalts, into which it passes by a gradual transition, but in every case in which a rock shows a notable percentage of olivine it has been assigned to the basalts. The andesites are not less numerous than the basalts; they form probably the greater part of the volcanic series. The majority are in the same condition as the basalts above described, and their investigation resolves itself into a determination of pseudomorphs. Dark basic augite andesites occur on the east side of Torduff Reservoir and in the Dean Burn (group }), alternating with the basalts above described and resembling them closely in appearance and in state of decomposition. Many of these rocks contain a few small crystals of olivine, but these are less numerous than in the basalts, and there is much more felspar. Some of these lavas are vesicular. In the Dean Burn there are also dark andesites which show pseudomorphs of bastite after idiomorphic hypersthene, a mineral easily recognised by the shape of its pseudomorphs. The association of basic andesites with olivine basalts is not confined to this locality, and as a rule the andesitic rocks preponderate in the upper part of such an assemblage, while the basalts are more numerous below. Similar augite andesites — which possibly contained a little olivine—are found in the White Hill plantation above Bonally and on the north of Shearie Knowe. On the high ridge between Aller- muir and Caerketton (group d) a dark red andesite occurs in a very fair condition of preservation. It bears much resemblance to some of the Cheviot Rocks (Yetholm, etc.) and contains pseudomorphs after hypersthene. The porphyritic felspars are still fresh, and the groundmass has originally contained a fair percentage of glass (hyalopilitic). This is a type of andesite which recurs in all the Lower Old Red volcanic areas. Far to the south-west vesicular augite andesites form the summits of the East Kip and West Kip Hills. In the lavas of Hillend (group g) there are augite and hypersthene andesites mixed with the Hillend basalts, and, like them, much decomposed. The Blackford Hill Type of Andesite—The well-known rock of * © Ancient Volcanoes of Great Britain,” vol. i. p. 274. 3 34 Volcanic Rocks of Pentland Hills. Blackford Hill (group g), extensively quarried for road metal, is a dark grey finely crystalline and non-vesicular andesite, which weathers with a reddish colour and is intersected by veins of jasper and chlorite. It contains few porphyritic crystals, usually small plagioclase felspars, but occasionally also biotite or augite, though always decomposed. The rock consists mainly of small, lath-shaped, simply-twinned felspars, with a well-marked fiuxion arrangement. Between them lie minute grains of calcite mixed with chlorite, obviously secondary after original augite. Iron oxides, apatite and zircon al:o occur. Fresh augite or biotite never appear in the sections, and the former presence of biotite is inferred only from the shape of certain pseudomorphs which are covered with dusty magnetite. A similar rock, equally decomposed, is found in Cayie- side Quarry, north-east of Swanston, and at Busie Law, Swanston, there is an andesite of somewhat similar character but containing many plates of pale brown biotite still perfectly fresh. Their edges are not corroded, and this rock differs somewhat from those of Blackford Hill and the Braids, though resembling them in more than one feature. An analysis of the Blackford Hill andesite has been executed by Dr. Pollard, and is quoted below. Frankland’s analysis of the Busie Law rock* igs not very satisfactory, but is given for comparison. In both cases the alkalies are high and the silica comparatively low. The felspar must be andesine, oligoclase and orthoclase. In many respects the andesite of Blackford Hill recalls the mugearites, but it differs from these by the absence of olivine. Andesite, Andesite, Blackford Hill. Busie Law. Anal. W. Pollard. Anal. Frankland. Si0Q,.. 6. ee BT 52:00 TiO, .. ae as 3 a ‘91 ai Al,O, cee 18-76 Fe,O3 ee ee 442, 9:38 FeO .. ee “ie a he 3°23 114 MnO... of ie ae i ‘17 ae (Co,Ni)O.. iss ee ais tr. ia CaO .. ees a ts 6:16 9:23 sro .. oes at ae aa nt. fd. en BaO .. a Si oe is nt. fd. hs MgO... .. we we 1:32 2-04 Kus we we 209 1-66 NEO: See ce. tee. 413 4:17 Li,O .. oa 25 <4 sid tr. ae H,0 105° C. aa, ey ake 20 wee H,0 above 105° C... sy es “82 Bee oO Se age a 63 0:32 CO, .. 6 af ns Me 247 ne Cl ine at ae a ay nt. fd. s aes es = a 45 tr. 100°55 101°38 * Sir A. Geikie, “‘ The Ancient Volcanoes of Great Britain,” vol. i. p. 274. Andesites and Trachytes. 35 BIOTITE AND HORNBLENDE ANDESITES AND TRACHYTES. In the Pentland Hills, rocks belonging to these categories have a fairly wide distribution and are of considerable importance, but many of the rocks are too much decomposed to render a minute dis- crimination possible. This is especially true when the felspars have been kaolinised, for though the nature of the ferromagnesian minerals can often be inferred from the shapes of their pseudomorphs, the outlines yielded by sections of the monoclinic and triclinic felspars are too much alike to yield any clue to the original species when none of its optical characters can be observed. These rocks weather in a very characteristic fashion. Kaolinisation, which results in the production of claystones, is their typical mode of degeneration. They range in colour from pale yellow or pale grey through various shades of lilac to brown or bright red and often mottled. This characteristic is sufficient to distinguish them in the field from both the basic and the acid rocks. Biotite Andesites—Some of the red porphyritic lavas which occur among the rhyolites of Capelaw contain much plagioclase and biotite, and may be best described as biotite dacites. Very similar specimens, though in much worse preservation, occur in several other localities. In no case, however, are their felspars fresh, and it is not impossible that some of them may belong to the trachytes. Near Fairmilehead, on the road leading south from Kdinburgh, there are decomposed hornblende biotite andesites, with many black-rimmed pseudomorphs after hornblende and biotite, and specimens were obtained in Torduff Hill and at Torphin Crags which seem to belong to the same category. Trachytes—The members of this group, like the biotite andesites, are usually much decomposed, The best preserved are those of Woodhouselee (group f). In the quarry north of the mansion house of Woodhouselee a biotite trachyte is found (312). It is a dark grey or reddish grey rock with phenocrysts of sanidine and fresh biotite. In the microscopic section, the felspars, though somewhat weathered, show simple twinning under polarised light; a few are polysynthetic and belong to oligoclase: the felspar phenocrysts are sometimes 4 in. in diameter. The biotite is in thin dark brown hexagonal plates, which have black “corrosion borders” but still preserve well their original crystal outlines. In addition to the larger biotites, small scales of the same mineral occur in the groundmass, together with many elongated sanidine microliths arranged with their long axes parallel in winding fluxion strains. These are surrounded by a fine-grained turbid substance which was originally a finely crystalline felspathic base, but is now partly replaced by kaolin and quartz. A few crystals of zircon, iron oxides, apatite and ill-defined stains of limonite are also present in the slides, but calcite is apparently absent. The silica percentage of this rock has been determined by Mr. Barrow as 63:3.* Other specimens of biotite trachyte, in which the felspars can still be identified were obtained in the south-east side of Castlelaw, about 100 yds. north of Castle Knowe. The rock is very.similar to * Sir A. Geikie, “The Ancient Volcanoes of Great Britain,” vol, i. p. 279, 36 Volcanic Rocks of Pentland Hills, that of Woodhouselee, containing porphyritic sanidine and biotite in a fluidal felspathic groundmass, but many minute irregular patches of quartz are scattered through the section. Most of these are secondary, and it does not seem likely that quartz was present as an original ingredient. The tendency to silicification is more marked in the trachytes than in the biotite and hornblende andesites, The collection contains several other rocks from the same vicinity (south face of Castlelaw) which may possibly belong to this group, though their felspars are much decomposed and their groundmass contains secondary quartz. They are all pale rocks which have been porphyritic and highly felspathic, and have contained phenocrysts of corroded biotite. Some of them may belong really to the rhyolites and dacites, but none show porphyritic quartz, and the finely granular quartz in their groundmass has probably been set free by the decomposition of their felspars. THE Brarp Hitts Rocks. The purplish or lilac “claystones” of the Braid Hills (group /) are among the most decomposed in the whole area, and it is only after examining a large suite of sections both of them and of others of similar type in the Pentland Hills that we are able to formulate definite conclusions regarding their original nature. Sir Archibald Geikie considers that they are for the most part fine volcanic dust derived from the explosion of felsitic or orthophyric lavas.* Bands of breccia do occur in several parts of the Braid Hills, but the microscopic sections do not support the hypothesis that the rocks are chiefly of this nature. Wherever they are not entirely decomposed it is easy to make out in them the remains of an originally crystalline structure, and though, on the whole, the specimens are very like one another, yet it is possible to trace belts of rock which maintain the same character along the strike. Thus the rocks extending from the hotel to Liberton Tower are different from those of the south part of the Braids golf course, and these again are not exactly the same as those which form the ridge of the Buckstone and Mortonhall golf course. These claystones consist almost entirely of felspar and of its decomposition products. The felspar rarely gives its characteristic reaction to polarised light. It is very frequently replaced by kaolin, muscovite and secondary quartz. Although the last-named mineral is constantly present it is never very abundant, and there is less silicification than in the majority of rhyolites and trachytes in the Pentlands. Occasionally strings and veins of quartz may be detected in the slides. Calcite is also not common, but some specimens (for example, that of which an analysis is quoted by Sir Archd. Geikie +) contain it in fair amount. Biotite is the only other important primary mineral. It is some- times fresh but has always suffered from corrosion and has darkened borders. Usually, however, it is entirely decomposed, and its nature can only be assumed from the form of its pseudomorphs. Apatite, often of the turbid pleochroic variety which is common in volcanic * « Ancient Volcanoes of Great Britain,” vol. i. p. 324, { Op. cit. vol, i. p. 278, Trachytes of Braid Hills. 37 rocks, zircon and iron oxides in numerous small grains are also present in the slides. Very frequently the rocks of the Braid Hills are porphyritic, the biotite forming thin irregular plates 1 millimetre in diameter and the felspars being of varying size, but mostly small and perfectly formed. Some of these rocks, however, show pseudomorphs after crystals of felspar not less than 2 millimetres in diameter. Only rarely and in the best preserved specimens can the nature of the groundmass be inferred from the appearances in microscopic section. It is sometimes of the “ trachytic ” type, fine-grained, fluidal, with small felspar microliths and grains of iron oxide ; at other times it has consisted of fairly large (-2 or °3 mm.) grains of felspar without good crystalline form. It is clear that these rocks belong either to the biotite trachytes or biotite andesites. Their high percentage of felspar, the small amount of ferromagnesian minerals, the scarcity of secondary quartz and calcite, and the porphyritic and fluidal structure are all in harmony with this suggestion. Rocks practically identical in character with those of the Braids and Mortonhall are found in Torduff Hill (group ec). Sir Archibald Geikie cites an analysis by Prof. E. Frankland of the rock from the Braid Hills, but it seemed of sufficient importance to have a typical specimen, as fresh as possible, from there and from Mortonhall analysed in the laboratory of the Geological Survey by Dr. Pollard. The three analyses are given below— Trachyte (Hornstone). Trachyte (decom- Braid Hills. (decomposed), posed), Mortonhall. Braid Hills Quarry. Anal. Prof. Frankland. Anal. W. Pollard. Anal. W. Pollard. Si0, tee 6473 65°82 63°02 TiO, east Oke “40 43 Al,O3 os «» 17-01 16:37 15°50 Fe,O3 5% «. 2°35 2°06 4°81 FeO ee ti og 18 13 . MnO sue Pa “24 16 ‘10 (Co,Ni)O .. oe is tr. (2) tr. CaO ae .. 419 2°74 2°67 BaO i +4 a ‘03 nt. fd. MgO tee 166 ‘Bl 62 K,0 4 .. 8°27 3°48 3:96 Na,O ‘ we B75 4°24 4°46 Li,0 ae wi as tr. tr. H,0 105°C. .. 58 72 1:00 H,0 above 105° of 1:85 1:49 Os oh. 25. by 21 16 os 5 26 nt. fd. 03 CO... * 1:84 1:82 99°24 100°61 100°20 These analyses confirm the inferences drawn from microscopic examination of the rock. The silica percentage is by no means abnormal for the trachytes, so that there is little probability that the rock has been silicified. The alkalies are high, especially when we remember that the type of decomposition, which the rock exhibits, namely kaolinisation, is characterised by a general diminu- * This rock is stated to contain also 0-13 per cent. FeO and 2°42 per cent. CO,. Sir A. Geikie, “‘ Ancient Volcanoes of Great Britain,” vol. i. p. 278. 38 Volcanic Rocks of Pentland Hills. tion of these constituents. The lime and magnesia are both very low, especially in the rocks analysed by Dr. Pollard, while the high percentage of water indicates a considerable amount of decomposition. RHYOLITIC AND Fensitic LAvas. Rocks belonging to this group occur on several horizons in the Pentland Hills, one being that of the Howden Burn and Bell’s Hill (group ¢), while another extends from Caerketton through Castlelaw to Walston (group ¢) near the south edge of the Sheet. They occur also near Woodhouselee. They are recognised without difficulty in the field by their pale pink or reddish colour and their flinty appear- ance. The best examples in the collection from the lower series are fine-grained, non-porphyritic, flesh-coloured felsites from Capelaw and the glen between Bell’s Hill and Harbour Hill. The microscopic sections show that some of these rocks consist of a fine slightly granular turbid felsitic material, without trace of spherulitic or tluxion structures, and containing no porphyriticingredients. Many of the specimens from Capelaw show small lath-shaped felspars in afluidal groundmass. These rocks have undergone secondary silicifi- cation but this is not sufficient to mask their original characters. They have been and are still compact crypto-crystalline felsites and rhyolites. In the upper group (e) the banded and spotted pinkish felsite which forms Caerketton Crags is well known. It is accompanied by acid breccias and tuffs, and under the microscope shows considerable silicification. In places, the slides consist of fine crypto-crystalline felsitic material, but elsewhere this is replaced by a mosaic of rather coarse secondary quartz in irregular grains, which are rendered turbid by innumerable specks of iron ores and kaolin and the minute cavities they contain. In the striped varieties the silicification is often most pronounced along certain bands, and when the rocks are spotted it is usual to find that the round spots consist entirely of a secondary quartz mosaic. These spots (which are usually from } to jg in. in diameter) are the remains of spherulites which have been replaced by silica. Traces of the original radiate structure persist. They have been arranged in sinuous lines parallel to the fluxion. The rock, when unaltered, was a spherulitic felsite probably with bands of more or less vitreous character alternating with others which were crypto-crystalline, but it may have been a true obsidian. Here and there it contains small pseudomorphs after porphyritic felspar, but no trace of quartz phenocrysts appears in the slides. No pseudomorphs after biotite or other ferromagnesian mineral can now be detected; but grains of iron ore occur, many of them in the centres of the spherulites. The rhyolites and acid breccias of Caerketton can be followed towards the south-west into Castlelaw, along the west face of which they are well seen. Their general character is the same throughout, and the secondary silicification is equally pronounced in both localities. In their decomposed condition the possibility that dacites and silicified trachytes occur among them cannot be excluded, and this indeed seems highly probable. Many of the Castlelaw specimens show a fine fluxion-banding, but none of the specimens collected are Rhyolites and Felsites. 39 so rich in spherulites as those of Caerketton. Remains of porphy- ritic felspars, entirely replaced by kaolin and quartz, occur sparingly. The matrix is partly a fine felsitic substance, partly a mosaic of turbid secondary quartz grains. The original felspar both of matrix and phenocrysts is usually represented only by the products of its decomposition, but in some of the rocks small lath-shaped felspars of a second generation are abundant. In certain slides they are mostly acid -plagioclase, in others there is a large proportion of sanidine. In Braid Law (group c), near the southern extremity of the volcanic series, the rock is a reddish yellow or salmon-coloured rhyolite with marked fluxion-banding and occasional drawn out vesicles. It is one of the best examples of the group in the Pentland Hills, as it contains many cavities filled with clusters of quartz crystals and also phenocrysts of decomposed sanidine felspar. Its matrix is a felsitic or, in some places, microcrystalline quartzo-felspathic aggregate which still preserves most of its original characters. No doubt it was somewhat coarser-grained than the Caerketton and Castlelaw felsites; it is far less completely silicified, and was probably less acid, as in many features it shows some resemblance to the trachytes. A second generation of felspar was present in small prisms in the groundmass, and some obscure pseudomorphs probably represent original biotite. Near Woodhouselee, along with the trachyte (group /) above described, well-preserved and characteristic rhyolites occur. One of these, from a quarry } mile W.S.W. of Woodhouselee House, has been analysed by Dr. Pollard. The analysis is that of a typical rhyolite, and as the felspars are in fairly good preservation, there is no reason to suspect that the rock has been greatly silicified. It contains porphyritic crystals of sanidine, oligoclase, and brownish green biotite (the last without black corrosion borders) in a fluidal matrix of small elongated laths of sanidine (and some acid plagioclase) mixed with little irregular grains of quartz and fine, red, dusty hematite. Patches of secondary chalcedonic silica and of kaolin appear here and there, occupying what were probably irregular cavities, but the rock was not highly vesicular. Secondary silica is deposited also along the cleavage planes of the biotite. Magnetite, zircon and apatite are the only accessory minerals. The matrix gives the impression that it was in large measure crystalline, and that there was originally little vitreous base. Although some of the quartz may be secondary it seems unreasonable, in view of the chemical composition of the rock, to place it among the trachytes. Rhyolite from quarry at edge of fir plantation } mile W.S.W. of Woodhouselee House. (Analysis by Dr. Pollard.) SiO, .. #8 23 a a8 ws He .. 72°78 TiO... es “3 i “i a Ke na "19 ZrO, ..- a oa ea ai oe ee Ste 03 BUOg ac: ea. ee “Ge de (as caer JS) Mie MejQectest: et: ” Y ' JOUVNV1dS3 ’ aS S39NIud ONZ LSM 56 Caleiferous Sandstone of the Edinburgh District. Below the Castle Esplanade, on the slope facing Johnstone Terrace, the highest members of the Upper Old Red Sandstone, con- sisting of variegated sandstones, with fragments of cornstone, and red and green marls, are exposed. No organic remains have been found in these sandstones. This correlation is based solely on their litho- logical resemblance to the sandstones beneath Salisbury Craigs and at Oraigmillar, which, as already indicated, have yielded fish remains characteristic of this formation. These sediments pass beneath the basal beds of the Cementstone group, which, along the High Street, have a general dip towards the E.N.E., at angles varying from 10° to 15°. Thin basaltic tuffs (BZd!, Fig. 3) and a basaltic lava of Dunsapie type (yBd!, Fig. 3) have been recorded near the head of Jeffrey Street, where they are interstratified with the cementstones. Perhaps the most notable section in this part of the Old Town was that exposed in the course of the excavations for the new offices of The Scotsman newspaper, where upwards of 120 ft. of strata were laid bare.* Special interest attaches to this section from the oc- currence in it of a band of dark carbonaceous shale, which yielded plants, ostracods and fish remains. The recognisable fragments of plants, determined by Dr. Kidston, comprise Adiantites lindsceformis (now known as Rachopteris inequilatera), Stigmaria and various fern stems. The worms are represented by Spirorbis carbonarius and S. helacteres, still attached to some of the plantremains. The ostracods, named by Mr. Kirkby, include Leperditia subrecta, L.okent,L. wrightiana (2), Kirkbya spiralis (abundant), Argillecia equalis, Aglaia cypridini- formis (?), Bythocypris sublunata (?). The higher crustacea are represented by the portion of a carapace of Tealliocaris [Anthra- palemon), while fragments of scorpion skin show the presence of Arachnids. The fishes, determined by Dr. Traquair, are represented by scales of Rhizodus and of a paleoniscid fish.t In a brief descriptive note on the Ostracoda from this section, Mr. Kirkby remarks that all the ostracods are marine forms, with occasional estuarine habits in the case of some of them. Judging from their vertical distribution in other districts than Mid-Lothian, he suggests that the position of the strata in which they occur is in the lower half of the Cementstone group of the Calciferous Sandstone, and probably on the horizon of the Randerstone or Billow Ness beds.t At the base of the steep declivity beneath Salisbury Craigs, the cementstones are abruptly truncated by a fault with a downthrow to the west, which brings them in contact with the Upper Old Red Sandstone (Fig. 3). Beyond the dolerite sill of Salisbury Craigs (Plate ITI.), which seems to have been intruded along or near the boundary line between the Upper Old Red and Carboniferous forma- tions, the shales, cementstones and sandstones of Ballagan type again appear and occupy the hollow known as the Hunter’s Bog (Fig. 3 and Map at end of volume). In the Camstone Quarry, near the base of the series, some beds of cementstone are charged with Estheria peacht, a small bivalve phyllopod crustacean, which has been found by Mr. Macconochie in the Cementstone group of East Lothian in association with well-known Carboniferous forms. * Trans. Edin. Geol. Soc., vol. viii. p. 5. + ‘Summary of Progress,’ Mem. Geol. Sur. for 1898, p. 131. t Trans. Edin. Geol. Soc., vol. viii. p. 16. ‘HOUNANIGY “LVAG SMOHLUY ‘SDIVYD AUAISIIVS ‘ENNOUDAUOT AHL NI ANOISGNVE TAY CIO yaddf] HALIM ‘“ALINAHOSN], dO ATHY AAISAULN TT aLV Id Volcanic Rocks of Arthur’s Seat. 57 The total thickness of strata belonging to the lower portion of the Cementstone group in the Hunter's “Bog is about 600 ft. Above this horizon the deposition of sediment was interrupted by the extrusion of the volcanic succession of Arthur’s Seat which now falls to be described. B.N.P., J. H. VOLCANIC ROCKS OF ARTHUR’S SEAT. After a long period of quiescence volcanic energy again manifested itself, early in Carboniferous time, in the Edinburgh region where at least two important volcanoes, namely, those of Arthur’s Seat and Corston Hill, for a time discharged lavas and tuffs upon the floor of the lagoon on which the sediments of the Cementstone group were laid down. From time to time subsidiary orifices were opened, such as that which must have supplied the Craiglockhart ashes and lava, while possibly another is represented by the Castle Rock of Edinburgh. A general characteristic of these early eruptions of the Calciferous Sandstone period in Mid-Lothian and other parts of Scot- land is the wide distribution of extremely porphyritic basaltic lavas, usually in association with others of the mugearite type. In Arthur’s Seat, at least two separate vents are to be found, the larger of which is of a composite character, showing a slight displace- ment of the focus of eruption during the life of the voleano. Perhaps the most interesting feature in the history of this voleano is the evidence of the gradual infilling of the central crater by ashes and lavas, while the intercalation of sediment at various horizons clearly. shows that the waters of the lagoon from time to time gained access to the crater. Another feature is the intermittent recurrence of the same type of igneous products; thus the Long Row, representing the earliest volcanic extrusion of the hill, is of the same type as the basalt of the Lion’s Haunch, which is the youngest product of the volcano that has been preserved. Intermediate in age between these two, lies a varied series of agglomerates and lavas, belonging to at least three distinct types. The geological structure of Arthur’s Seat has long been a fascinating subject of inquiry among geologists. In 1839 Maclaren published the results of his detailed examination of the rocks of the hill,* which showed his comprehensive grasp of the volcanic history of this area and laid the foundation of all subsequent research regard- ing it. Many of his conclusions have been confirmed by later investigators: one, however, has been disputed, namely, that the volcanic materials belong to two distinct periods of eruption, separated by a vast interval of time. In proof of the latter view he maintained, that the mass of agglomerate which forms the central portion of the hill is merely a cake resting unconformably on an irregular land surface carved out of the older lavas. He regarded the basalt of the Lion’s Head as a plug filling up the vent which supplied the later agglomerate. In short, he believed that between the two periods of igneous activity an interval of time elapsed during which the older volcanic series and associated sediments had been folded and subjected to prolonged denudation. In the second edition of his work, published * “ Sketch of the Geology of Fife and the Lothians,” 1839, Ist ed. pp. 1-49. 58 Calciferous Sandstone of the Edinburgh District. in 1866, Maclaren stated in a note that he had abandoned the view of two periods of eruption. Arthur’s Seat was first mapped on behalf of the Geological Survey by Sir Archibald Geikie, who confirmed Maclaren’s observa- tions and accepted his original interpretation. Following a sug- gestion made by Edward Forbes he considered that the unconform- able newer group might be of Tertiary age,* but at a later date he regarded them as more probably connected with the volcanic rocks associated with the sandstones of Permian age in Ayrshire and Dumfriesshire.t His detailed mapping of the Edinburgh district led to the conclusion that the volcanic series of Calton Hill is merely a faulted portion of the Whinny Hill sequence, and therefore in- cluded in the basement portion of the Calciferous Sandstone series. In 1875 Professor Judd published an important paper bearing on the structure of Arthur’s Seat, wherein he advocated the theory that the central agglomerates and their associated igneous rocks were contained within a vent from which the bedded lavas and ashes had been erupted. t The evidence obtained during the recent revision of Arthur’s Seat by the Geological Survey has confirmed Professor Judd’s contention and at the same time has shown the accuracy of much of the detailed work of Maclaren and Sir A. Geikie. The Volcanic Succession outside the Vents—On the declivity east of Hunter’s Bog, the cementstones pass underneath the lowest of the contemporaneous volcanic rocks of the hill, which is represented by the basalt lava of the Long Row (I in Fig. 3 and in Map). It not only caps the ridge between the Hunter’s Bog and the Dry Dam and is continued to the north of St. Anthony’s fault in the crag of Haggis Knowe, but it also appears to the south of the neck, where it gives rise to the escarpment of the Loch Craig, as was recognised at a very early date by Ami Boud § (see Map at end of volume). Consisting of dark porphyritic basalt of the Dunsapie (Lion’s Haunch) type, but with less conspicuous phenocrysts than the typical rocks, it is slaggy towards the top and bottom, but markedly columnar in its central portion. The manner in which the overlying fine ashy sediments descend into the irregularities of the slaggy upper surface of the basalt seems to demonstrate that it isa true lava flow. This feature may be conveniently studied in the road section in the Queen’s Drive above the Loch Craig. In places the ashes that fill up the fissured and uneven surface of the basalt are slightly indurated, thus indicating that the lava must have retained a considerable amount of residual heat when the tuffs were deposited. The basalt of the Long Row is followed to the east of the Dry Dam by about 100 ft. of strata, consisting chiefly of well-bedded basic tuff with numerous sedimentary intercalations, mostly calcareous. Near St. Anthony’s Well two calcareous bands are specially con- spicuous, one near the base and the other near the top of the tuff (L, Fig. 3). The lower one, exposed beside the small reservoir that 1 “Sketch of the Seeleey of Fife and the Lothians,’ 1866, 2nd ed. p. 47. * “ Geology of the Neighbourhood of Edinburgh,” Mem. Geol. Sur., 1861, p. 123. + ‘* Ancient Volcanoes of Great Britain,” vol. ii. p. 68. t Quart. Jour. Geol. Soc., vol. xxxi. p. 131. § Essai géologique sur P Ecosse (Paris, 1820), p. 196. Volcanic Succession in Arthur’s Seat. 59 supplies the well, is about three feet thick, and is siliceous, and con- cretionary. It is associated with dark sandy shale full of plant remains. From these beds the late Mr. David Grieve obtained the fossils mentioned by Dr. Traquair.* Plant remains are also found in the ashy beds overlying the limestone. In the path leading up to St. Anthony’s Chapel concretionary white limestones occur inter- bedded with the ash, and these are traversed by rootlets of plants which must have grown in situ. The band of limestone near the top of the tuff is to be seen a little farther up the bill slope, and also contains roots or stems of plants in which the structure is preserved. The highest beds visible in this section consist of grey flaggy calcareous sandstone with an occasional admixture of ashy material. South of the vents this group of ashes is exposed above the Loch Craig, where the Long Row basalt crosses the Queen’s Drive. Here they consist of fine-grained reddish tuff and ashy sandstones. After a space concealed by turf, which must represent nearly 100 ft. of similar strata as shown by their debris, a white limestone like that seen at St. Anthony’s Well protrudes through the turf and dips steeply towards the east (see Map). A similar section is exposed eastwards from the foot of the Loch Craig on the Duddingston Road, where the ashy sandstones contain concretionary calcareous nodules. Up to this point the sequence found on both sides of the vents is in very close agreement, but above this horizon there is a marked variation. In order that this variation may be clearly realised, the succession, occurring to the north and south of the vents, is presented below in descending order— WHINNY HILL SEQUENCE (NORTH OF THE VENTS). No. XX lava. A basalt of Markle type. Nos. XVI-XIX lavas. The Parson’s Green group of Mugearites with thin ashes. Nos. VII-XV lavas. Basalt flows of Markle type with thin ashes. Nos. III-VI lavas. Basalt flows of Craiglockhart type, but rarely con- spicuously porphyritic. Upper Ash of Dry Dam containing no fragments of Markle type. No. II lava. Craiglockhart type, but not conspicuously porphyritic. Lower Ash of Dry Dam containing no fragments of Markle type. No. I lava. The Long Row basalt of Dunsapie type. DUDDINGSTON SEQUENCE (SOUTH OF THE VENTS). The upper ash or agglomerate of Duddingston containing abundant blocks of Markle type. Two basalt flows of Markle type also occur here, well up in the agglomerate, and the latter passes under a group of lavas (Markle basalt and a mugearite) exposed on the slopes of Dunsapie. The mugearite flow, the highest rock visible, is probably of earlier date than the mugearites of the Parson’s Green, and the section becomes ob- secured by drift at a much lower level on this side than to the north. Lower Ash of Duddingston containing no fragments of Markle type. Loch Craig basalt. The asymmetrical development of the volcanic series, indicated by the two sections in the above table, suggests that the vent may have been active at the beginning of the volcanic history of this area. In confirmation of this view it may here-be stated, that the existence of an early formed central cinder cone is indicated by the behaviour of the second ash in the Dry Dam, while the neck itself can be divided into an older portion free from blocks of the Markle * Trans. Roy. Soc. Edin., 1903, vol. xl. p. 689. 60 Calciferous Sandstone of the Edinburgh District. type of basalt, and a later portion in which they occur. These points will be dealt with in the sequel. Succession above the Lower Tuff of the Dry Dam North of the Vents. —tThe lower ash and sediments of the Dry Dam are overlain by a second flow of basalt (No. II in Fig. 3 and in Map), which can be best studied in the small crag underneath St. Anthony’s Chapel on the north side of St. Anthony’s fault. The rock resembles the Craiglockhart type, but with the olivine and augite less conspicuously porphyritic and greatly decomposed. The flow is slaggy throughout, and has an extremely irregular upper surface, the depressions and cracks of which are filled in with fine tuff and bedded limestone. South of St. Anthony’s fault, the outcrop of this lava is interrupted for a short distance by a basaltic intrusion of the same type as the flow; it is, however, markedly columnar and makes a conspicuous feature on the north side of the Dry Dam. Beyond this intrusion the lava with its characteristic features can be followed to the head of the Dry Dam. In the section exposed in the small crag under St. Anthony’s Chapel the ash filling in the cracks of No. II lava can be traced upwards into a continuous band of well-bedded tuff with occasional large bomb-like masses of basalt, some nearly a foot across. The ash is here about four feet thick, and a thin layer near its top is nearly black owing to the presence of carbonaceous matter, and is hardened by infiltration of iron. This bed has been referred to by Dr. Traquair as having yielded to Dr. MacBain * a tooth of Rhizodus. Fragments of Calamites, Stigmaria, and the remains of Hlonichthys striatus, Callopristodus pectinatus (determined by Dr. Traquair) were obtained by the Geological Survey from this band of tuff. The ashes at this point have been plicated by the drag of the succeeding lava flow, the overfolding indicating that the lava moved in a northerly direction over beds still in a soft and pliable condition. South of St. Anthony’s fault the tuff can be followed con- tinuously to the edge of the vent, rapidly increasing in thickness and in the coarseness of its materials (see Map). Only fragments of basalt of the type of the underlying lavas have been obtained in this deposit. Next in order at St. Anthony’s Chapel comes the third lava (III in Fig. 3 and in Map), forming the crag on which the ruin stands. It is petrographically similar to No. II, but with a compact central portion slightly vesicular and remarkably columnar in structure. Its upper part near St. Anthony’s Chapel is much brecciated, as if by explosive emission of gases. South of the fault where it gives rise to a continuous crag, it is rendered conspicuous by its columnar central portion with its orange-coloured incrustation. The dark slaggy upper part of the flow here also attracts attention owing to the masses of bedded limestone with which its cavernous spaces have been filled. Similar features are illustrated in the succeeding lava flow (IV in Fig. 3 and in Map), which is traceable on both sides of St. Anthony’s fault, on the one side as far as the central vent, and on the other to the crag overhanging St. Anthony's Chapel. An interesting feature may be noticed where the upper portion of * Trans. Roy. Soc. Edin., vol. xl. p. 689. Volcamic Rocks of Arthur's Seat. 61 this flow forms the crest of the ridge, to the south of the fault. At this point a clearly defined layer can be recognised by the large size of its porphyritic constituents. Although the line of demarcation between the two types of rock can be readily traced, the passage is not abrupt and is parallel with the flow banding of the underlying finer-grained rock, showing that differentiation had occurred within the magma, at least as regards the formation of the phenocrysts before the flow had ceased, and probably before the lava had been extruded. The fifth flow is a basalt of the same type as No. IV, and illustrates most of the features just described. In a small escarp- ment near its southern extremity, its weathered columnar central portion recalls the appearance of the columns in the celebrated Cheese Grotto at Bertrich in the Eifel. Along the southern half of its outcrop the fifth lava flow is succeeded by a sheet of basalt of doubtful relationship. It is a coarsely porphyritic rock of normal Craiglockhart type, resembling the upper portion of the fourth flow. The characteristic slaggy character is, however, absent at the top and bottom of this sheet, and its thickness is great compared with its lateral extent, so that it differs widely from the undoubted flows with which it is associated. This evidence therefore favours the view adopted tentatively in the mapping that this rock is an intrusive mass. The lava next in order (No. VI in Fig. 3 and in Map) is traceable from side to side of the Whinny Hill, is of considerable thickness, and repeats some of the features presented by the fourth and fifth flows. It is the last of the group of finely porphyritic lavas of the Craiglockhart type which began with No. II flow in Arthur’s Seat. The seventh lava flow is only known at the north end of the hill where it extends upwards for a few hundred yards from the bend of the Queen’s Drive east of St. Margaret’s Loch. It is the first of a group of basalt flows with conspicuous phenocrysts of labradorite (Markle type), which were mapped by Sir Archibald Geikie under the name of “ Porphyrite.” The overlying group, comprising eight flows (Nos. VIII-XV in Fig. 3 and in Map), form the main part of the Whinny Hill, the outcrops of most of which extend right across the hill. Although there is no important bed of ash in the series, the slagey surfaces of the different flows are usually separated from each other by tuff, which helps to set forth the bedded character of the volcanic materials. Columnar structure is not a marked characteristic of the lavas of this group, indeed they are more or less vesicular throughout with very irregular upper surfaces. The last feature is well illustrated on the east face of the hill about half-way between Dunsapie Loch and Parson’s Green, where the top of No. XII lava flow is exposed in a small scar facing the north. The upper two or three feet are seen to be composed of a rough heap of slaggy clinkers, many of which, in the arrangement of their phenocrysts and their vesicles, show a rude flow structure conforming more or less to the outlines of the separate masses. This is not an agglomerate resting on the top of the lava but is an integral part of the latter, as can be clearly seen in the section. Between these clinkers and reaching down into the more solid portions of the flow there extends a red 62 Calciferous Sandstone of the Edinburgh District. ashy sandstone constantly showing traces of bedding, which, in the larger cavities, is inclined in the general direction of the bedding planes of the rocks of the hill. The relations of the tuff to the uneven surface are also exhibited on the exposed dip slope of the lava, where wisps of slaggy basalt protrude in places through the covering of ash. The most important of these bands of tuff is to be seen at the side of the Queen’s Drive at the north-east corner of the Park, where it separates the fourteenth ai.d fifteenth lava flows. Next in order come mugearite lavas (X VI-XIX, Fig. 3), probably four in all, which are easily distinguished by their non-porphyritic character, their platy flow structure, and a tendency to assume a rude columnar character. The lowest of these flows (No. XVI) is exposed at the north-east extremity of the park, the boundary wall being built upon the bared upper surface. Although the top is here not particularly vesicular, the lowest portion of the succeeding ash bed is seen to descend into the irregularities of the surface. A section of the upper part of this ash is exposed in Scone Gardens, where it dips to the east at an angle of 20°. The rock is a fine reddish volcanic grit about 20 ft. in thickness, which is succeeded by a lava (No. XVII in Fig. 3 and in Map) that has been recently opened up and quarried for road metal. Probably the same flow is exposed in a cutting at the back of the engine shed of the Locomotive Depét of the North British Railway not far to the north, where it is succeeded by two bands of mugearite with thin intercalations of tuff. In the last-named section the uppermost of the mugearite lavas is separated by a thin bed of ash from a higher porphyritic flow, thus showing a reversion to the Markle type of lava. This rock, which is fresher than most of those of the Whinny Hill, probably represents the last of the extrusions in the volcanic sequence of Arthur’s Seat. The top of this bed is not visible, being covered by a thin coating of drift and by the basement beds of the 100-ft. beach. None of the lavas or ashes of the Whinny Hill can be traced southwards with certainty beyond the Queen’s Drive at the north end of Dunsapie Loch, the relations of the isolated areas of lavas east of Dunsapie to those of Whinny Hill being hidden beneath boulder clay. Succession above the Lower Tuff of the Dry Dam on the South Side of the Vents towards Duddingston.—The fine tuff associated with the limestone band overlying the lava of the Loch Craig (No. I, Long Row), which has been identified with the lower ash of the Dry Dam, is here succeeded by a mass of coarse well-bedded agglomerate (BZd? in Map) dipping to the north of east at the same average angle as the rocks of Whinny Hill. A feature which at once distinguishes this agglomerate from either of those in the Dry Dam is that the larger fragments are mainly composed of the Markle type of basalt with large porphyritic felspars. One of the blocks in this agglom- erate measures nine feet across. This mass of pyroclastic material is succeeded by two lava flows of Markle type (zBd'), which form an escarpment obliquely crossing the slope of the hill below the level of the Queen’s Drive. At a somewhat higher horizon finer agglomerate is associated with a band of white limestone, containing black patches Volcanic Rocks of Arthur’s Seat. 63 of calcite and chert, which is exposed at intervals in the slope above the road, and is also seen by the Queen’s Drive, where it bends to the north to Dunsapie Loch. North of the Duddingston entrance to the park the continuation of the section is concealed by drift. Dunsapie Crag is composed of intrusive dolerite (YD in Map), which on the east truncates two lava flows dipping towards the east, the lower being a porphyritic basalt of Markle type and the upper a mugearite lava showing the characteristic platy structure. The relations of these isolated exposures to the lavas of Whinny Hill are quite uncertain, but it seems unlikely that this mugearite can be on the same horizon as the flows exposed at the north-east corner of the park. In the latter section the mugearite lavas lie between basaltic flows of Markle;type, and it is probable that the Dunsapie mugearite represents a still earlier lava stream which did not reach the Whinny Hill. Comparison of Sections North and South of Vents——As already indicated, the lower portion of tuff with the limestone band exposed above the basalt of the Loch Craig on the south side of the vents corresponds in position and lithological characters with the ashes and sediments of the Dry Dam. Above the first 150 ft. the correspondence ceases. No lavas of Craiglockhart type occur on the south side of the vents, and the succeeding flows of Markle type, so conspicuous in the Whinny Hill, are represented to the south by agglomerates made up in part of this type of basalt with only subordinate outpourings of lava. The present configuration of the larger vent is of later date than the formation of the whole of the lower portion of the volcanic pile, including all the lavas of Craig- lockhart type; but the lack of agreement in the details of the section on each side points to the earlier existence of a small orifice occupying part of the site of the larger one. In this connection the rapid thickening of the upper agglomerate of the Dry Dam towards the south becomes very significant. In fact, to judge by the sudden increase in thickness of the band and concurrent increase in the size of its contained blocks, it seems certain that at this point the bed must have once formed portion of a small cinder cone. The limited distribution of the lava flows of Craiglockhart type can readily be accounted for by supposing that the uprising lavas breached the cinder cone at some point on its northern side. Similar considerations might also account for the predominance of agglomerate to the south and of lavas to the north, when, at a slightly later date, the volcano was producing the basalts of the Markle type in association with mugearites. As might be expected, the Calton Hill section, to be described later, combines many of the features which distinguish the two sides of the vent in the present area. The Vents of Arthur's Seat—A glance at the Map shows that the boundary of the materials constituting the central part of the hill is a line of very marked discordance. To the north-west of Samson’s Ribs it truncates the Upper Old Red Sandstone, and when traced eastwards to Dunsapie Loch it traverses the outcrop of the cementstones and a large portion of the volcanic series. Either the agglomerate which makes up the greater part of the material inside the line is lying as an 64 LIONS HEAD VENT VENT HAUN CH , LIONS ARTHUR'S SEAT UONS HAUNCH BASALT DUNSAPIE THE MEADOWS , SALISBURY GRAIGS S™ LEONARDS Caleiferous Sandstone of the Edinburgh District. TT Bza yaa BV BV 1500 FEET 1000 Fie. 4.—Section across Arthur’s Seat from the Meadows to Dunsapie, showing the position of the two Volcanic Vents. (See description, Fig. 3, p. 55.) unconformable cake upon the denuded edges of the surrounding rocks as Mac- laren originally supposed, or it rises steeply through these rocks, and fills a vent as advocated by Professor Judd. The main line of argument adopted by Professor Judd depends upon the close resemblance between the products of what had been previously supposed to belong to quite distinct periods of eruption. With increasing petrographical knowledge, the importance to be attached to evidence of this nature has become more apparent. In the case of the blocks contained in the agglomerate and the intrusions by which it is injected, the records of Scottish vulcanicity point to the conclusion that they could not have been produced except during the Calciferous Sandstone period. On this ground alone any hypothesis based on unconformability is extremely improbable, and this conclusion is strengthened by the field evidence in support of the opposite view, which now falls to be described. As shown on the Map, the area occupied by the discordant material in- cludes the central eminence of Arthur’s Seat and extends east to Dunsapie. It can be subdivided into two unequal portions representing separate vents, the boundary between them being marked by a line drawn approximately from the north end of the Raven’s Rock to the head of the Dry Dam (Fig. 4 and Map atendofvolume). The smaller orifice to the north-west of this line, including the summit of Arthur’s Seat, may be termed the Lion’s Head vent, and the larger one to the south-east the Lion’s Haunch vent (Plate I.). The Lnon’s Head Vent.—In this orifice there is everywhere a well-marked con- centric arrangement of the constituents of the agglomerate with steep inward dip, while the upper part of the basalt intrusion of the Lion’s Head rests in a cup-shaped depression, conforming more or less to the bedding of the agglomerate (Fig. 4). The stratification of the agglomerate is indicated by the alterna- tion of coarser and finer layers. The The Vents of Arthur’s Seat, 65 included blocks consist almost wholly of basalt of Craiglockhart and Dunsapie types, which impart a greenish tinge to the rock except where it is locally stained red. No fragments of the highly por- phyritic Markle basalts have been detected here, though they are common in the agglomerate of the Lion’s Haunch vent. Another characteristic is the relatively finer texture of the agglomerate in the smaller neck. It is probable that the Lion’s Head orifice was active only during the earlier stages of the history of the volcano, that is, before the extrusion of the greater part of the Whinny Hill lavas. The boundary of the Lion’s Head vent is clearly indicated along its northern margin where it truncates the cementstones forming the eastern slopes of the Hunter’s Bog and the lava flow of the Long Row. Thence it runs east and west at right angles to the strike of the adjoining lavas and ashes. A thin dyke of brecciated basalt has been injected along the line of junction and can be followed for about fifty yards. The basalt of the Long Row, when it approaches the margin of the vent, shows signs of great disturbance and shatter- ing, but the actual junction is concealed under surface débris. A little farther down the slope, bands of altered cementstone are found in contact with the dyke, and are bent down towards the junction. Inside this intrusion the ash of the neck can be seen to dip away from the dyke at angles of 45° to 50° and to be stepped down by numerous small faults (see Map at end of volume.) The western boundary is entirely concealed under talus. The nature of the junction line on the south-east side is indicated by the exposure at its south-west limit where the relation of the agglomerates of the Lion’s Haunch to those of the Lion’s Head vent can be seen in clear section in the gully known as the “Gutted Haddie” descending the western front of the hill (see Map at end of volume). The line is evidently that of a neck junction, and there is a marked discordance between the materials filling up the two orifices. The comparatively fine agglomerates dipping north-east under the basalt capping of the Lion’s Head are abruptly truncated against a highly inclined plane along which there are obvious signs of movement (Fig. 4). On the other side of the plane lies the coarse red agglomerate characteristic of the Lion’s Haunch, dis- tinguished from that just described by the presence of fragments of the Markle type of basalt. This deposit is also bedded and dips at an extremely high angle towards the south-east (see Map at end of volume). That this inclination is due to central subsidence rather than to deposition at the angle of repose of the material is shown by the presence of a bed of sandstone, greatly crushed but traceable for some distance and conforming with the high inclination of the agglomerates. Far down the section, beds occur rich in fragments of a basalt resembling that of the Lion’s Head, and at the very top of the “Gutted Haddie” a breccia occurs in contact with this basalt and entirely made up of its fragments although lying to the east of the division line between the two agglomerates (see Map). This breccia is affected by lines of crush, nevertheless it has the appearance of an original scree formation, and, what is particularly significant, it passes ‘laterally into the normal Agelomerates of the Lion’s Haunch, 5 ° 66 Calciferous Sandstone of the Edinburgh District. These phenomena seem to point to the existence of two vents, that of the Lion’s Head and that of the Lion’s Haunch. The latter came into operation at a slightly later date than the former, and was drilled partly alongside and partly within the limits of the original orifice. The constituents of the older neck, including the intrusion of the Lion’s Head, actually formed part of the boundary wall of the new vent and supplied screes which mingled with the exploded material. Thus it appears that the basalt of the Lion’s Head, although the youngest rock of the older vent, really belongs to the early suite of eruptions that produced the agglomerate with which it is so intimately associated. The rock is a fine-grained basalt of the Dalmeny type identical with that of the Castle Rock of Edinburgh to be described in the sequel, and closely related to the Craiglockhart type of basalt of the lower part of the Whinny Hill. On the west side of the hill, in the cliffs just above the footpath that traverses the talus, the roots of the Lion’s Head intrusion are exposed as a series of ramifying dykes, uniting upwards to form a stem which passes nearly vertically through the agglomerate for about 175 ft., and finally spreads out more or less parallel with the bedding planes of the agglomerate (Fig. 4). A marked flow structure is visible, which everywhere follows the marginal limits of the rock, while at the same time there is a rudé columnar structure at right angles to the fluxion lines. Two additional ex- posures of basalt occur within the Lion’s Head orifice, the chief one being a small dyke from two to three feet across, that rises vertically through the bedded agglomerate a little to the north of the “ Gutted Haddie” gully. It is a porphyritic basalt different from that of the Lion’s Head. The margins of the dykes show a platy fluxion structure and the centre is highly vesicular and amygdaloidal. Lion's Haunch Vent—tThe materials filling up the Lion’s Haunch orifice are more varied than those in the smaller vent just described. While agglomerate predominates, there are also undoubted lava flows at three different levels, together with sandstones, marls and cementstones. Massive intrusions also occur within the vent. The section exposed on either side of the Queen’s Drive, from Powderhouse Corner to the escarpment of the Loch Craig, furnishes evidence regarding the complex nature and arrangement of the materials inside the vent, and also of their relations to the bedded rocks outside the limits of the orifice (see Map at end of volume). The Raven’s Rock above the road at Powderhouse Corner forms part of a crag that runs south from the gully of the “Gutted Haddie” to the west end of Samson’s Ribs and consists of a series of slaggy porphyritic basalt lavas of Dunsapie type, associated with breccias, ashes, and occasional beds of red marly tuff. The manner in which the finer tuffs and sediments fill the uneven surfaces of the slaggy lavas leaves no doubt as to the superficial origin of the latter, while the occurrence of such deposits with their even bedding planes indicates that at the time of their formation they must have been nearly horizontal and continuous, though now either vertical or highly inclined towards the east. Hence there is here evidence of the central subsidence having affected the materials of the Lion’s Haunch Neck. In’ this section the rocks are traversed by several veins of intrusive basalt resembling the lavas themselves, but it “LVAG SMUAHLLY ‘sdIY S,NOSNWVG “LINDA HONAVH S,NOI'T AHL NIHLIM Livsvg UVNWATOO ‘AI FLV Td Lion’s Haunch Vent. 67 is uncertain whether they have emanated from the main mass of Samson’s Ribs or are more directly connected with the production of the lava flows. Where this group crosses the road at the first bend, their strike is deflected to the south-east so as to run almost parallel with the road and also with the boundary of the vent, the dip being north-easterly at high angles. Here the intrusive basalt of Samson’s Ribs splits up the group, and part of the breccias belonging to it flanks the western side of this intrusion as far down as the Duddingston Road, where the line between the two rocks is irregular and nearly vertical. The upper portion of the group obviously overlies the basalt of Samson’s Ribs and is exposed on both sides of the road. The well-preserved roche moutonnée exposed in the Queen’s Drive at this point belongs to one of these lava flows. The massive intrusion of Samson’s Ribs, so well known on account of its columnar structure, is a basalt of Dunsapie type (Plate IV.). Viewed from the Duddingston Road the most significant feature is the manner in which the steeply inclined columns bend outwards and become almost horizontal as they approach that road, as if chilled against a nearly vertical face. Indeed, the basalt of Samson’s Ribs appears to have welled up along the margin of the vent and to have extended laterally chiefly among the lavas and breccias of the group just described. It must have been injected after the extrusion of the latter as it sends an important tongue into the overlying red agglomerate which now falls to be described. This tongue is well seen above the Queen’s Drive and makes a conspicuous feature owing to the slight radiation of the fine columns. The junction of the red agglomerate with the uppermost member of the underlying volcanic group within the vent can readily be traced from the “Gutted Haddie” above the Raven’s Rock to the Queen’s Drive. The agglomerate is well bedded even in its coarsest form, the stratification being indicated by the arrangement of the large blocks, which consist chiefly of basalt of Dunsapie or Lion’s Haunch type together with fragments of the Markle type of basalt, the latter being readily recognised by the abundant phenocrysts of felspar. At irregular intervals there are intercalations of fine ash and even of quartzose and calcareous sedimentary materials. - In the first cliff exposed above the road after passing the tongue of columnar basalt proceeding from the intrusion of Samson’s Ribs there is a considerable thickness of these coarse agglomerates with a steep dip towards the north-east. About 30 yds. east from the beginning of the cliff, a few feet of ashy sandstone and cement- stone are overlain by a slaggy and often brecciated basalt lava of Dunsapie type. The irregular slaggy top of the flow with its cracks and hollows filled in with tuff is repeated by a fault oblique to the Queen’s Drive, and a continuation of the lava is also seen a little below the road. For the next 70 yds. very coarse agglomerate with finer intercalations occupies the cliff with the same high inclina tion towards the north-east. At this point a mass of porphy- ritic basalt, several square yards in extent, is seen to be cut off to the east by a nearly vertical bed of fine red agglomerate. The mass is like a dyke intrusion, but is more probably only a very large block in the agglomerate which is extremely coarse at this point and filled with fragments of similar basalt, 68 Calciferous Sandstone of the Edinburgh District. The fine red agglomerate is followed by a slaggy lava flow of Dunsapie type, showing signs of flow-brecciation, which appears in the section for the next 100 yds. The very irregular surface of the lava is overlain by a few feet of red ashy marls with sandstone and cementstone bands which descend into the crevices of the slaggy surface. Here again the nature of these bedded sediments, which much resemble many of the rocks of the Cementstone group found outside the vent, precludes the hypothesis that they could have been formed at the angle at which they now lie, and it is certain that the continuation of the outcrop of this lava flow in the road section with an average ENE. and W.S.W. strike has been determined by central subsidence. The same deflection of the strike is observable in the agglomerates which overlie this lava at a point near where the road section is hidden by the retaining wall. = Lion's ay Ha = TNH 9 Bas, 72 Lr oy otal &% 2 TS ee ko MASSIVE “2225. OGE OF AwAGGLOMERATE ~~ BV-s2t4 . ws a ee me es ey 24 : Fic. 5.—Junction of Lion’s Haunch Basalt with massive agglomerate (BV), Loch Craig lava (yBd?), tuffs, and sediments in Queen’s Drive. Fragments of white limestone in agglomerate (++). Horizontal distance about 1000 ft. These phenomena, indicating central subsidence and drag against the vent wall, are supported by the evidence of disturbance such as faulting, slickensiding and shattering, that is everywhere apparent in these rocks. ~ In the concealed ground the marginal line must cross the road obliquely since an outcrop of the sandstones and cementstones under- lying the intrusion of the Girnal Craig with a N.W. and §.E. strike can be traced to within 70 ft. of the road section just described. The edge of the vent can be seen a little farther up the hill in the section rendered classic by the descriptions of Maclaren, Geikie and Judd (Fig. 5). The exposures here are far from perfect and the nature of the junction has for the most part to be inferred from the relation of isolated outcrops. There can be no doubt, however, that a line running obliquely up the hill in a north-east direction separates two distinct groups of rocks, On the north-west side of this Lion’s Haunch Vent. 69 boundary the agglomerates of the road section continue for a space dipping towards the north-west at low angles. At this point they are characterised not only by the abundance of blocks of the Markle type of basalt, but also by the presence of many large fragments of fine-bedded ashy sandstone, and pieces of limestone similar to the deposits occurring above the Long Row basalt on both sides of the hill. These are interrupted by a tongue of basalt connected with the intrusion of the Lion’s Haunch (Fig. 5), beyond which a crag of agglomerate resembling that just described projects through the turf, but with a south-east dip. On the south-east side of the line the basalt of the Loch Craig is well exposed and is followed, at the Queen’s Drive, by the characteristic ashy sandstones with a north- east dip, while, up the hillside,a prominent rib of white limestone or cementstone (Fig. 5), similar to that occurring in the Dry Dam near St. Anthony’s Chapel, can be traced to within a few yards of the projecting crag of agglomerate already mentioned. Its outcrop then ceases, and although the section is much grassed over it is highly probable that the limestone doeg not continue farther in this direction. The principal feature of the section is the very obvious truncation of the Loch Craig (Long Row) basalt by the agglomerate (Fig. 5), for although the tongue of Lion’s Haunch basalt intervenes at one point it does not affect the relationship of the other two rocks. Apart from its bearing upon the questions discussed, the contact of the basalt of the Loch Craig with that of the Lion’s Haunch is of great interest. Both Sir Archibald Geikie and Professor Judd are agreed that the tongue is intrusive against the older lava, and according to either interpretation a certain lapse of time must have intervened between the production of the two rocks of similar petrological character. Since it has now been shown that basalts of the Markle type and also mugearites are abundantly represented in the agglomerate into which the Lion’s Haunch rock is intruded, it is clear that the eruption of the Lion’s Haunch basalt marked a reversion to the earliest type of lava represented in the hill after the voleano had passed through a highly complicated development. While the recurrent phase is demonstrated in this particular section by the actual conjunction of the newer and older products, it is equally illustrated by the relations of the Dunsapie mass and other intrusions and lava flows within the neck to the agglomerate with which they are associated, and in some cases also to the lavas outside the vent. The characters which distinguish the Lion’s Haunch rock from the contiguous lava are its more coarsely porphyritic texture, its greater freshness, its comparative freedom from vesicular structure, its more jointed appearance and its reddish weathering. By these means it is possible to distinguish the junction line of the two rocks. Eastwards from the section just described the position of the boundary line of the vent is quite uncertain. The existence of the neck in this direction is inferred from exposures on the north side of the orifice to be described in the sequel. Although the available evidence does not favour the view, it is possible that the agglomerate with the limestone containing the dark chert nodules, and also the lava flows of Markle type, described in the section on page 62 as 70 Calciferous Sandstone of the Edinburgh District. forming the bedded series on this side of the hill, may really be included within the vent. At Dunsapie the evidence becomes more definite. The disposition of the columns within the massive intrusion at that locality indicates that it forms part of a sheet inclined towards the north-east ; but the intrusive character is shown by the manner in which it truncates the lavas exposed upon the eastern flanks of Dunsapie (Fig. 4). To the west of Dunsapie Loch there is an exposure of a very coarse ag- glomerate including blocks up to five feet across chiefly of Dunsapie type of basalt, together with fragments of Markle type and mugearite. From this point up to the northern extremity of the Lion’s Haunch basalt a series of shallow excavations was made at intervals of a few yards, which indicate that this grassy slope is underlain by coarser and finer agglomerates with similar contents (Fig. 4). In places where the finer agglomerate showed an arrangement of the material, the dip was found to be towards the north-east. The relations of the main mass of the Lion’s Haunch intrusion to the agglomerates exposed beneath its western escarpment clearly indicate that it is a superincumbent sheet inclined towards the north-east like the agglomerate (Fig. 4). It has been suggested that the basalt in- trusion of Lion’s Haunch and Dunsapie may be portions of the same sill, though now cut off from each other by denudation; but Dr. Flett, who has had exceptional opportunities of studying the two rocks microscopically, is of opinion that they present differences which make them readily distinguishable from each other, thus inaking this hypothesis highly improbable. It will be observed that‘in this part of the vent there are few, if any, indications of differential movement due to central subsidence so obvious in the portions hitherto described. All the phenomena connected with the dip of the materials could be fully accounted for by the supposition that here the bedding remained approximately horizontal until the folding of the region as a whole. Such evidence is opposed to the view that the igneous products of Arthur’s Seat might belong to two epochs separated from each other by a period of great earth movement accompanied by denudation. To the north of the agglomerate a triangular area, extending from near Dunsapie Loch to the head of the Dry Dam, is occupied by porphyritic basalt of the Dunsapie type (yBd1 in Map at end of volume). In some of the exposures the rock is seen to be thoroughly slaggy, and, when viewed in connection with the contour of the ground, it suggests the presence of at least two lava flows. At the col at the head of the Dry Dam two ribs run up the hillside, and it is a remarkable fact that these are in such direct continuation with the escarpment features made by the outcrops of lavas II and III of the Whinny Hill succession, that only by attention to the different petrographical characters of the rocks can one be convinced of the existence of the line of discontinuity in the intervening hollow. This continuity of feature accompanied by the difference of the rocks on each side of the line did not escape the acute observation of Maclaren, who, however, tried to account for the presence of these lava flows by inserting a fault along the line we now take to be the outer edge of the neck. He assumed in fact that the lavas were downthrown portions of some of the porphyritic basalts of the The Vents of Arthur's Seat. 71 Whinny Hill. Sir Archibald Geikie found this hypothesis to be untenable and rightly placed these lava-form rocks with the ag- glomerates of the central part of the hill. It may be pointed out now that microscopic investigation shows that these rocks belong to the Dunsapie type of basalt so well represented in the lavas, agglomerates, and intrusive masses of the vent, and clearly distin- guishable from the Markle type of basalt that characterises the lavas of the upper part of the Whinny Hill with which Maclaren originally compared them. These lava-form rocks probably underlie the agglomerates upon which the Lion’s Haunch sill rests, and therefore seem to be in the same stratigraphical position in the vent as the much faulted lava of similar type exposed in the Queen’s Drive on the south side of the hill (Fig. 5). Some small isolated exposures of brecciated slaggy basalt of Dunsapie type protrude through the turf in the hollow between the Lion’s Head and the Lion’s Haunch which also appear to belong to lavas intercalated in the agglomerate about this horizon. Agglomerate, evidently underlying the lowest of the lava flows within the vent overlooking the Dry Dam, is exposed at the junction of the two paths that lead up to the top of the hill on the north side. The pyroclastic material dips easterly, thus agreeing generally with the inclination of the bedded rocks outside. This exposure must be near the junction of the Lion’s Haunch vent with the older orifice to the north, and the next exposures on the hill face clearly belong to the latter. Vent near Camstone Quarry—Having described the great central vents of Arthur’s Seat, we may now direct attention to a subsidiary vent giving rise to an elongated mound on the dip slope of Salisbury Craigs between the Cat Nick and the Camstone Quarry. Along its major axis, which lies E.N.E. and W.S.W. it measures fully 200 yds. and its breadth is about 70 yds. (see Map at end of volume). At its eastern extremity the agglomerate with which it is entirely filled cuts through the Upper Old Red Sandstone and contains numerous fragments of that material. Elsewhere its junctions are not exposed, but since it lies obliquely to the outcrop of the sand- stones its relations, like those of the agglomerates on Arthur’s Seat, can only be those of unconformity or intrusion in the form of a vent. Here there is additional evidence to associate this agglomerate with the Carboniferous period since it has been greatly indurated by the dolerite intrusion of Salisbury Craigs which, for reasons to be given in the sequel, is itself probably of Lower Carboniferous age. The included blocks at once recall the lavas of the lower portion of the Whinny Hill, while the Markle type of basalt is absent, so that it may be inferred that its period of activity was restricted, like that of the Lion’s Head vent, to the earlier portion of the volcanic history of Arthur's Seat. INTRUSIVE IGNEOUS ROCKS OF ARTHUR'S SEAT AND CASTLE ROCK. Reference must now be made to the intrusive rocks occurring in Arthur’s Seat, which comprise (1) the sheet of Heriot’s Mount and St. Leonard’s Craig, (2) the Dasses and the Girnal Craig, (3) the 72 Caleiferous Sandstone of the Edinburgh District. dolerite sill of Salisbury Craigs and (4) the intrusive mass at Duddingston, With regard to the rock of the Dasses its intrusive nature was clearly recognised by the early observers. It is a conspicuously porphyritic basalt of Dunsapie type occurring as a thin sheet, overlain by three irregular lenticular masses, which thin out among the surrounding sediments. The latter show obvious signs of having been disturbed and indurated by the molten rock. The occurrence of a sill of the same type and occupying a like stratigraphical position both to the south of the vents (the Girnal Craig), and also in the faulted area to the west of Salisbury Craigs (St. Leonard’s Craig), points to a greater extension for this intrusion than might have been expected from the appearances presented by the Dasses themselves. The correlation of the basalt of Girnal Craig with that of the Dasses was made by Maclaren, who realised its intrusive character and the alteration of the overlying cementstones as seen on the shore of Duddingston Loch. The basalt of St. Leonard’s Craig has been linked with that of the Dasses in view of the discovery of Upper Old Red Sandstone fish remains in the sandstones underlying Salisbury Craigs, from which it was inferred that the cementstones into which the St. Leonard’s basalt has been intruded belong to the Cementstone group of the Hunter's Bog, repeated by a fault (Fig. 3). Although the basalt sill of the Girnal Craig, as shown on the Map, appears as if truncated by the edge of the vent, the section is obscure at this point, and it is by no means certain that such is actually the case. In fact the resemblance of the basalt of the Dasses to the in- trusive rocks of the Lion’s Haunch, Dunsapie and Samson’s Ribs suggests that this sheet may have been injected at a time subsequent to the establishment of the main orifice. The description of the great teschenite sill of Salisbury Craigs * is given in another chapter (p. 276), since, from its petrographical character and from its disappearance in the field in thin branching veins in the direction of the larger vents, it almost certainly belongs to a slightly later period of igneous activity which followed after the complete extinction of the Arthur’s Seat volcano. The intrusive mass at Duddingston presents no point of special interest. It is a basalt of the Dunsapie type, whose intrusive character can be at once inferred from the manner in which it truncates the fine tuffs and calcareous bands that overlie the Loch Craig (Long Row) basalt. The Castle Rock, though somewhat removed from Arthur’s Seat, may, however, be dealt with in the present section. In character it is a fine-grained basalt of Dalmeny type resembling the rock of the Lion’s Head, and, like it, may belong to the early part of the voleanic history of Arthur's Seat. It is manifestly a plug rising almost vertically through the Upper Old Red Sandstone, against which members of the Cementstone group are brought by faulting (Fig. 3). It is quite possible that the Castle Rock may have served as an orifice for the emission of lavas. although no such connection can now be established. -* Prof. Bonney first separated the intrusions of Salisbury Craigs, Samson’s Ribs and St. Leonard’s Craig, Proc. Geol. Assoc., 1878, pp. 503, 608. Cementstones and Volcanic Rocks of Calton Hill. 73 VOLCANIC ROCKS OF CALTON HILL. As was demonstrated by Sir Archibald Geikie, the Calton Hill is merely a portion of the volcanic platform of Arthur’s Seat which has been shifted westwards by the Calton fault. The succession agrees closely with that of the Whinny Hill, but, as might be expected, shows local variations, especially in the greater de- velopment of ashes, wherein it approaches the sequence on the south side of the great vent in Arthur’s Seat. The dip of the volcanic rocks being in the same general direc- tion as in Arthur’s Seat, the lowest beds are exposed towards the west where they are under- lain by the cementstones, the latter being truncated by the Colinton fault (Fig. 6). The basalt of the Long Row does not appear to have extended so far to the north, as the local base of the volcanic series exposed in street excavations consists of fine ashes intercalated with sediments of Ballagan type, and including at least one flow of basalt of Craiglockhart type. In a general way these represent the ashes and sediments of the Dry Dam and are in like manner overlain by porphyritic basalts also of Craiglockart type (xBd?, Fig. 6). The first of these lavas possesses a central columnar belt passing upwards into a slaggy upper portion with cavernous spaces infilled with fine ashes and bedded limestones, thus present- ing a striking similarity to the features of No. III lava of the Whinny Hill succession. Near the top of this group the lavas _. alternate with fine ashes and = a GRANTON 'SANOSTONES da ‘ ABBEYHILL SHALES 1500 FEET 1000 4 SCALE CALTON HILL 250 500 0 Fic. 6.—Section across the Calton Hill, Edinburgh. STANDREW SQUARE quartzose sandstones, as seen in 2 ae road sections, the whole being SS oo | wn overlain by a mass of well- se bedded agglomerate containing —_ os numerous blocks of basalt of Markle type and occasional thin lenticles of lavas of similar composition (BZd!, Fig. 6). From this 74 Calciferous Sandstone of the Edinburgh District. point up to the National Monument several alternations of por- phyritic basalt of Markle type with thin beds of tuff are well exposed (zBd!, Fig. 6). This succession can be examined in the road section leading obliquely up the hill behind the High School and in the paths and cliffs overlooking the High Calton. The group ends with an ash band extending right across the hill and visible in all the road sections, which is succeeded by a typical platy mugearite lava (oWd!, Fig. 6). Two similar flows separated by ash bands are to be seen in the road-cutting on the top of the hill outside the wall which divides the public grounds from the Regent Gardens. Rocks of this type make up the highest visible lavas of the Calton Hill, and in this instance there seems to be no reversion to lavas of Markle type, as in Arthur's Seat. The volcanic rocks of the Calton Hill are overlain in natural sequence by shales of Ballagan type, containing entomostraca, which are exposed in the gardens behind Regent Terrace. In the No. I Borehole at Abbeyhill, recorded by Mr. John Henderson, a thickness of upwards of 300 ft. of dark shale was proved to overlie these volcanic rocks.* These sediments represent’ the highest members of the Cementstone group in the neighbourhood of Edinburgh. VOLCANIC ROCKS OF CRAIGLOCKHART. The volcanic rocks of Craiglockhart in the south-western suburbs of Edinburgh lie on the western limb of the anticlinal fold that runs through the city. They consequently dip towards the north-west, and like those of the Calton Hill are truncated by the Colinton fault. They give rise to two conspicuous craggy hills separated by a drift-filled hollow that follows the course of an unimportant fault. The best ex- posures are found on the western hill, where about 100 ft. of bedded ashes are overlain by a massive columnar lava of about equal thickness. The tuffs are for the most part fine-grained, and almost entirely composed of small fragments of basalt, many isolated crystals of augite and olivine similar to those occurring in the overlying lava, and a slight admixture of quartz grains such as might have been derived from earlier formed sandstones. Occasional large blocks of basalt and sedimentary rock are not infrequent in the ash. Despite the well-bedded nature of the deposit no intercalations of normal sediment are observable, and it is quite probable that this deposit may have been formed as the result of a single eruption, as in the case of Monte Nuovo near Naples. The basalt lava overlying this tuff has been taken as the rock- type of a widely distributed group occurring at or near the base of the Carboniferous system in Scotland. The junction of the lava and the ash is well exposed in the crags at both ends of the hill, the western crag just south of the Hydropathic Establishment affording the best section. The base of the lava does not quite conform to the underlying ash beds but here slightly transgresses them, probably indicating the actual breaking up of the soft floor over which the lava flowed. The contemporaneous nature of the rock is suggested by its extremely slaggy character in this exposure, and is confirmed by the abundance of veins and cavities infilled with fine ashes and * Trans. Edin. Geol. Soc., vol. viii. p. 7. Craiglockhart Volcanic Rocks—Oil-Shale Group. 75 bedded limestone. Before the lava had cooled, some of the cavities appear to have been lined with a soft mud which has been baked and cracked by the residual heat, and the rents have been subsequently tilled in with ash of a coarser texture. Other veins, infilled with jaspery substance, are abundant, but these are probably of later origin and similar to examples frequently found in intrusive rocks. These occur in the columnar massive portions where the infiltrations of true sediment can very rarely be found. The slaggy upper surface of the lava is well exposed at one point on the slope over- looking the ruins of the Castle, but the upward continuation of the volcanic series is lost at this point owing to the Colinton fault. In the eastern hill the wider extension of the basement tuff is probably due to a slight roll over of the dip, and not to a thickening of the ash as might be supposed from looking at the Map. To the north of this hill the volcanic rocks seem to be faulted down against the edges of the Upper Old Red sandstones and marls exposed in the Myreside cutting of the Suburban Railway, near Craiglockhart Station. The tuffs and the basalt recall the lower part of the Whinny Hill succession of Arthur’s Seat, but since the Craiglockhart ashes have no intercalations of normal sediment similar to those of the Dry Dam, it seems more probable that the Craiglockhart volcanic group was derived from a local centre and not from the Arthur’s Seat vents. The great thickness of the Craiglockhart basalt tends to support this view. On this hypothesis it is not to be expected that the Craiglockhart volcanic rocks should have been strictly con- temporaneous with those of Arthur’s Seat. Evidence bearing on this interesting question has recently been supplied by some new exposures at the east end of the western hill, where sandstones and conglomerates and clay beds with calcareous concretions are seen in close proximity to the ashes, and dipping conformably with them. These beds strongly recall some of the rocks of the Craigmillar Sandstone group (Upper Old Red Sandstone), and, though this correlation has not been supported by fossil evidence, there is good reason for the belief that the Craiglockhart voleanic rocks are some- what older than any occurring in Arthur’s Seat, indeed they may actually lie at the junction of the Old Red Sandstone and Car- boniferous systems, like the volcanic rocks of the Birrenswark plat- form of Eskdale and Annandale. B.N. P. THE OIL-SHALE GROUP. Owing to the discovery of thin seams of oil-shale in-the Wardie Shales and in beds interleaved in the Granton Sandstone the base line of the Oil-shale group is now drawn at the bottom of the latter subdivision of the Calciferous Sandstone (see Fig. 2, page 52), instead of at the base of the Pumpherston Shales. Only the three lowest members of the Oil-shale group, namely, the Granton Sandstone, the Wardie Shales, and the Hailes Sandstone are represented in this district. In the Royal Terrace Gardens, on the north slope of the Calton Hill, a massive bed of sandstone, forming the base of the Granton Sandstone, overlies shales full of entomostracan remains, belonging to the Cementstone group, the dip being to the north of east at an angle of 23° Farther to the 76 Caleiferous Sandstone of the Edinburgh District. east dark shales of Wardie type are exposed round the dolerite sill of Lochend. These sections occur to the east of the great Colinton fault, to which reference has already been made (see Sheet 32), but the best exposures are to be found in the area west of this dislocation, and especially on the foreshore between Newhaven and the mouth of the river Almond, Sections are seen inland along the course of the Water of Leith near the Dean Bridge, and between Slateford and Juniper Green. Other exposures are to be found in the Suburban Railway cutting south of Gorgie Park Station, the cutting on the Barnton Railway near Davidson’s Mains, and in the quarries at Craig- leith, Hailes, Craigcrook and Davidson’s Mains. In this area the rocks have been thrown into a series of anticlines and synclines having a north and south trend, as was first pointed out by Mr. John Henderson.* One of these folds—the Granton anticline—extends from near Muirhouse on the coast west of Granton, southwards towards the southern end of Corstorphine Hill, and brings to the surface the Granton Sandstone and associated beds with a width of outcrop of over a mile between the quarries at Craigleith and Craigcrook. A second fold—the Leith anticline—stretches from Leith Harbour to St. Andrew Square in the city of Edinburgh, and is truncated at its southern extremity by the Colinton fault. Its western limb has a steep inclination between Princes Street and the Dean Bridge where the junction of the Granton Sandstone with the overlying Wardie Shales is exposed. Between these anticlinal folds, a well- marked trough—the Wardie syncline—extends from the shore at Granton to the south of Hailes Quarry, in which lie the higher beds of the group, namely, the Wardie Shales and the Hailes Sandstone. In this trough the latter is only known to occur between Kingsknowe and Hailes Quarry, but it is probably also represented by the sandstones about the mouth of the river Almond, though the relation of these sandstones to the strata above and below has not yet been satisfactorily determined. During the recent revision of this area oil-shales have been found to occur in these three divisions. An oil-shale containing fish remains overlies the sandstone in Hailes Quarry. A second band occurs in the railway cutting 100 yds. above Boags Mill on the Water of Leith, which probably lies in the Wardie Shales. A third oil-shale has been found on the south side of a new road running parallel with and immediately south of the Queensferry Road. Its locality is 60 yds. a little south of east of Ravelston Lodge, and the shales in which it occurs are intercalated in the Granton Sand- stone. On the coast section between Granton and Wardie several oil-shales have been discovered. The analyses of some of these shales are referred to in the economic section of this memoir (p. 351). The Wardie Shales are best exposed in the Wardie syncline on the shore between Trinity and the rock that projects seaward 330 yds. west of Granton Harbour, known as the General’s Rock. The following vertical section of these strata, as there exposed, has been prepared to show the sequence of beds in relation to the oil- shales which they contain :— * See J. Henderson, Truns. Edin. Geol, Soc., vol. iii. p..24, vol. vi. p. 29. The Wardie Shales. 77 Ft. In. Sandstones and grey PADS shales .. 60 0 Oil-shale 6 0 Black and grey shale.. . 20 0 Curly oil-shale (No. 3 analysis, see page 351) re 6 0 Blue and black shale with thin band of volcanic ash 6 0 Qil-shale < : a i 2 0 Blue and black shale . 8 0 Sandstone with stigmaria 20 0 Blue and grey papery shale .. : 35 0 Oil-shale with entomostracan bands 6 0 Curly oil-shale (No. 2 ae see page 391) 6 0 Poor shale a's 6 0 Blue oil-shale .. 4 0 Shale with entomostracan bands 4 0 Sandstone and grey papery shale 12 0 Grey papery shale and thin ironstone bands 28 0 Oil-shale (No. 1 analysis, see page ee 2 0 Sandstone ‘ 6 0 Nodular fireclay and thin coal 25 0 White sandstone ac 20 0 Black shale with plants : 55 0 Black shale with fish, coprolites and balls . 3 70 0 Thin grey band of voleanic ash an nA 2to4 0 Black shale... oi oe re Zk .. 25 0 0 Hard yellowish sandstone .. Bs “8 Bs i «6:18 Grey papery shales. ‘ Coal, formerly worked ‘at Wardie .. Black shales with black sandstones and dark limy beds.) An oil-shale (No. 4 analysis) and a band containing; 200 0 marine fossils in close proximity near the base.. : Top of the Granton Sandstones at the General’s Rock Three of the oil-shales of which analyses have been made lie within Granton Harbour: the fourth occurs near the General’s Rock. A specimen from the thin band of ash beneath No. 3 oil-shale has been examined microscopically and found to be a tuff probably of basaltic origin. The beds containing the ironstone nodules, so famous for their fish remains, occur low down in the group, and are to be found chiefly to the east and west of Granton Harbour. Most of the fossils have been obtained at the eastern end of the section near Trinity. The relations of the strata along the shore between the General's Rock and the mouth of the river Almond are somewhat obscure owing to numerous gaps in the section. West of the General’s Rock the projecting headlands are composed of sandstone, but the interven- ing sandy bays furnish little definite evidence beyond occasional exposures of shales. Lithologically they resemble the division of the Wardie Shales. West of Muirhouse the shore section is largely occupied by beach deposits. A band of tuff, the relations of which are uncertain,-is represented on the Map (Sheet 32) near Silverknowe, but it is believed to be intercalated in the lower portion of the Oil-shale roup. : Brief reference will now be made to the inland exposures of the lowest members of the Oil-shale group to the south of the typical section on the shore. Within the city of Edinburgh, strata belonging to the Granton Sandstone group were pierced in the tunnel of the 78 Calciferous Sandstone of the Edinburgh District. Old Edinburgh and Granton Railway, which extended underground from the Waverley Station to Scotland Street. The course ran nearly north and south and slightly obliquely across the axis of the Leith anticline, the crest of which lies beneath St. Andrew Square. On the west side of this axis, the Granton sandstones and the accompanying dark shales with ironstone nodules containing coprolites and fish remains have been exposed from time to time during building operations. At the corner of St. David Street and Princes Street, sandstones and shales and a thin coal scam, dipping towards the north-west, were laid bare during the rebuilding of Charles Jenner & Co.’s premises. Dark shales with ironstone nodules, belonging to this group and dipping north-west at high angles, have, from time to time, been exposed in Hanover Street and Princes Street, and along the same strike to the south-west at St. Cuthbert’s Church up to the Colinton fault. Similar beds, also dipping to the north-west, are still visible in the cutting of the Caledonian Railway. The gorge of the Water of Leith between Drumsheugh and Stockbridge has been carved in beds of this group, where they form the western limb of the Leith anticline as was shown by Mr. Henderson. Some of the highest beds in this section belong to the Wardie Shales. Following the eastern limb of the Wardie syncline to the south- west we find beds belonging to both groups in the Suburban Railway cutting near Craiglockhart Station. On the north-west side of the Colinton fault dark shales with ironstone nodules, belonging to the Granton Sandstone group, are seen dipping at high angles to the north-west, which, to the north of the Station, are succeeded by sandstones and shales with a similar inclination, while a little farther north the presence of the marine band indicates the lower part of the Wardie Shales. This group here contains shales with occasional sandstone bands and two seams of coal, one of which reaches a thickness of about two feet but contains thin strains of carbonaceous fireclay. These coals probably represent those of Caroline Park near Granton and the seams formerly worked near Wardie. These rocks are hardened and altered by two sills of dolerite. Strata belonging to these groups have been exposed north of Craiglockhart Hill, where they dip steeply to the north-west away from the Colinton fault. A coal exposed there in one of the quarries is probably the same as one of the seams in the Suburban Railway section, The Water of Leith, between Colinton and Juniper Green, traverses obliquely the southern end of the Wardie syncline. On its eastern limb the Granton sandstones dip steeply off the fault at the eastern side of the large stretch opposite Colinton, the rocks being also much disturbed. Two marine bands are seen in the bed of the river at Curriemuir and Woodhall, which must lie in the Wardie Shales, a short distance above their junction with the underlying Granton Sandstone. From Curriemuir to Currie, where the Colinton fault crosses the Water of Leith, the Wardie Shales are to be found at intervals in the river banks with a uniform dip to the east, showing that the strata lie in the western limb of the Wardie syncline. The highest members of the Oil-shale group in this district are Granton Sandstone, Wardie Shales, and Hailes Sandstone. 9 exposed in the Hailes Quarry, where the sandstones are inclined to the east at angles of 10° to 15°, and are overlain by. shales containing a band of oil-shale, an account of the analysis of which is given in the economic section (Chap. XVII. p. 351). The sandstones reappear in the east limb of the syncline in a quarry about half a mile farther to the east, near Kingsknowe Station. Black shales of the Wardie Shales series are laid bare in the Water of Leith at Redhall, dipping to the west beneath the sandstone in the quarry at Kingsknowe. As already indicated, the Granton anticline hag been proved to extend southwards beyond Ravelston House by means of various exposures of the strata. On its eastern hmb massive sandstones with an easterly dip have long been wrought in the famous quarries at Craigleith, where they pass beneath shales containing a calcareous band with marine fossils. The Granton Sandstone has also been worked in quarries near Craigcrook Castle, where it is inclined to the south-east, and still farther south it dips in a southerly direction near the dolerite sill of Corstorphine Hill. Northwards near Davidson’s Mains, on the west limb of the arch, the overlying Wardie Shales arein contact with the dolerite sill and are baked into a hard porcellanite, which has been largely quarried for road metal. They are also visible in the Barnton Railway cutting, a short distance farther north, with a similar westerly dip. The Wardie Shales and Granton sandstones are related litho- logically to the higher part of the Oil-shale series in which the oil shales are now worked, and the assemblage of fossils, consisting chiefly of fish and plant remains with a scarcity of marine types, is similar. Reference has already been made to the marine bands in the Wardie Shale series recorded by the older observers. They occur in the shore section near the base of the Wardie Shales at the General’s Rock, at Drumsheugh and the Dean Bridge in the Water of Leith, at Woodhall and Katesmill above Colinton, in the shale overlying the sandstone in Craigleith Quarry, in the excavation on the east side of the northern end of Corstorphine Hill, in the Suburban Railway cutting west of Morningside Station and in the cutting of the Barnton Branch Railway near Davidson’s Mains. Mr. Henderson, who was the first to call attention to these bands, considered that in most of these localities they belong to one horizon near the base of the Wardie Shales. Those in the quarry at the north end of Corstorphine Hill and in the Barnton Railway cutting were referred by him to a different position, but the field evidence seems to support the view that they represent the band near the base of the Wardie Shales. The fossils from these zones in the cabinets of Mr. John Henderson and Mr. Gall, Edinburgh, were described, as already indicated, by Mr. R. Etheridge, Jr. (see p. 49). Marine but not open sea con- ditions are proved by the occurrence of such brachiopods as Lingula and Discina and by cephalopods such as Orthoceras. Lamellibranchs and gasteropods also occur. The whole assemblage is similar to the organic remains found in the marine bands in the Lower Carboniferous rocks of East Fife, which stratigraphically represent the Oil-shale group. C.R, C, CHAPTER VIII. CALCIFEROUS SANDSTONE SERIES OF THE QUEENSFERRY, BROXBURN AND WEST CALDER DISTRICT. THE area extending from the shores of the Firth of Forth southwards to the Pentland Hills, which now falls to be described, is bounded on the east by a line drawn from the mouth of the river Almond to the village of Currie on the Water of Leith. Its western limit is defined by the outcrop of the Hurlet Limestone, which runs approximately in a north and south direction from a point in the Firth west of Blackness Bay southwards to Cobbinshaw Reservoir. It thus embraces the rich oil-shale fields of the Lothians between Queensferry and West Calder—the centre of the oil-shale industry in Scotland. The sequence of strata in this district ranges from the base of the Cementstone group to the top of the Calciferous Sandstone series, the most striking feature of the region being the remarkable development of the shale measures. The volcanic rocks of Arthur’s Seat are here represented by the basalt and mugearite lavas of Corston Hill, where they are associated with cementstones of Ballagan type. At Dalmeny and Dechmont there is evidence of brief outbursts of volcanic activity during the deposition of the Oil-shale group before the extrusion of the great succession of lavas and tuffs of the Bathgate Hills. The upper portion of the Calciferous Sandstone series,as already indicated, dips westward under the Carboniferous Limestone series of Bo'ness and the Bathgate Hills. The exact position of the boundary line between the two is often obscure, partly owing to the great covering of drift and partly because of the variability of the strata, which often renders correlation impossible even across areas only a few miles in breadth. Still more difficult is it to correlate the beds in this western district with those in Mid-Lothian or along the Haddingtonshire coast. The two Abden Limestones of Kinghorn, Fifeshire, bear consider- able resemblance to the Longcraig Limestones on the coast east of North Berwick, which are about 25 mls. distant in an E.S.E. direction, and it seems probable that the Lower Abden is on much the same horizon as the Lower Longcraig—the limestone, which, in East Lothian, is taken as the basement bed of the Carboniferous Limestone series. In Fifeshire, however, in the one-inch map 40, the base of this series has been drawn at the bottom of the thick limestone, exposed on the coast a little west of Seafield Tower, which comes next above the Abden beds, and has been regarded as the equivalent of the Hurlet Limestone by Sir A. Geikie.* * “ Geology of Central and Western os Kinross-shire,” Geol. Sur. Mem., p. 91. Oul-Shales of West Lothian. 81 Between Kinghorn and Charlestown in Fife, great changes in the lithological character of the strata supervene, and, as will be subsequently shown, the different limestones in these two districts cannot be correlated with confidence. The bed adopted as. the base of the Carboniferous Limestone Series at Charlestown has been correlated on the south side of the Firth of Forth with that at Whitebaulks, and the latter has been followed at intervals along the strike as far as Bathgate with considerable certainty. The tracing of this base-line has been aided by the almost continuous outcrop of the Hillhouse and Petershill Limestone for more than four miles between Hiltly and Bathgate. South of Bathgate the volcanic rocks disappear, and at the same time the limestones change their characters, which increases the difficulties in their correlation. In this southern area, the limestone at Cobbinshaw, which has been identified with the Hurlet, has been taken as the basal bed of the Carboniferous Limestone series. It is necessary to bear in mind that subordinate beds of marine limestone occur considerably below the base of the Carboniferous Limestone series in West Lothian as well as elsewhere, and that there is no paleontological break at the base. c.T.C, The geological structure of the shale measures of West Lothian and the adjoining part of Mid-Lothian presents certain general features which may now be briefly indicated. Throughout the greater part of the region the strata are arranged in a series of sub-parallel folds, the axes of which generally run in a N.N.E. and S.S.W. direction, whereby the oil-shales are spread over a belt of country sevéral miles in width. These arches and troughs are traversed by several more or less powerful faults, traceable for miles, which, at certain localities, produce large displacements of the strata. The Main Faults—In this district there are four important dislocations, all of which have a general easterly or north-easterly trend, and, with one exception, have a common downthrow to the north. The detailed mapping of the region has proved that though they profoundly affect the geological structure of the various mining districts, the axial folds can in many cases be traced across their ath. : The most northerly one, the Ochiltree fault, whose downthrow is to the south, begins a short distance to the south of Wester Ochiltree, and, passing north of Duntarvie and Dalmeny Church, enters the Firth of Forth at Drum Sands. The next dislocation is the Middleton Hall fault, which originates near Dechmont House and extends eastwards by Middleton Hall to Ingliston. Still farther south we find the Calder fracture, which begins to the north of Baad’s Mill, and passes by the south of West and Mid-Calder in the direction of Currie. It is regarded as a south-west branch of the Colinton fault. The fourth important line of disruption is the Murieston fault, which bounds the north side of the Wilsontown coal-field, and enters Sheet 32 to the west of Cobbinshaw reservoir. It truncates the volcanic rocks of Corston Hill on the north and joins the Calder dislocation near Dalmahoy House. The Main Hlexures.—On the north-west side of the West Cairn Hill in the Pentland Chain the Upper Old Red Sandstone and 6 82 Calciferous Sandstone of Queensferry and West Calder District. Calciferous Sandstone strata dip gently to the north-west for about three miles from the watershed, where they form the southern limb of a shallow syncline extending from Cobbinshaw reservoir to Dalmahoy Hill. Here the trough bends to the south-east round the Haugh Head arch and forms what may be termed the Balerno basin. North of this fold between Corston Hill and Selms the cementstones and the higher beds of the Upper Old Red Sandstone are again brought to the surface by a fold, which is truncated by the Murieston fault. The most prominent of the anticlinal folds is that of Pumpherston, about midway between the Firth of Forth and Cobbinshaw reservoir, in the centre of which lie the lowest workable oil- shales, in the form of a narrow ellipse, whose major axis runs north and south for two miles (see Sheet 32). On either side of this arch the strata form deep synclinal folds. The eastern basin, which underlies the drift-covered plain of Drumshoreland Muir, trends southwards for three miles to Mid-Calder (Fig. 7, p. 88). The western trough, extending from Pumpherston beyond Houston Wood to Dechmont, is broad and deep, being covered in the centre by a sheet of intrusive dolerite 200 ft. thick. This basin, which has an outcrop of the Burdiehouse Limestone on either side, runs northward for a distance of three miles from the river Almond at Livingston to Uphall. North of the Middleton Hall fault the Pumpherston anticline is continued in the low arch that extends from Broxburn to Niddry, and the deep basin that stretches northwards from Middleton Hall to Newbigging is beyond doubt the northern prolongation of the trough west of Pumpherston. The eastern trough is represented by the shallow basin which has been proved by minihg operations to occur at Hast Mains. North of the Ochiltree fault, the well-marked anticlinal fold at Hopetoun House and the adjoining Duddingston basin to the east may be the northern continuations of the Pumpherston and Mid- Calder flexures respectively (Fig. 9, p. 96). In the southern portion of the district, between Livingston and Cobbinshaw reservoir, the West Calder shale-field is of great economic importance owing to the repetition of the various oil- shales by folding and faulting. The principal tectonic features are two deep basins at Polbeth and Hartwood respectively, with an intervening low anticlinal ridge at West Calder village. Along the western border of this district the members of the Oil-shale group roll over an anticlinal fold which has been traced from West Harwood northwards by Burngrange, Mid-Breich, Dechmont, and Hangingside to Philipstoun Mill, where with a low pitch to the north-east it disappears. CEMENTSTONE GROUP. The members of the Cementstone group and associated volcanic rocks occurring within this district may be arranged in the follow- ing descending order :— d. Dark grey shales containing {remains of fishes, plants, and entomostraca ; black shales with fireclay and ironstone bands, coarse sandstones, and cementstone bands with intercalated beds of tuff, Cementstone Group. 83 ce, The volcanic rocks of Corston and Torweaving Hills representing the later part of the volcanic series of Arthur’s Seat. b, Conglomerate, purplish, red, yellow, white, and grey sandstones containing plant remains, with grey and green shaly partings. a. ee ene shales, soft red and green marls, with ironstone and cement ands. (a) An excellent section of the lowest subdivision is laid bare in the Linhouse Water to the north and west of Blackraw and about a mile and a half south of Mid-Calder. The lowest beds exposed are not far above the quartz dolerite sill of Selms which has been injected near the base of the Cementstone group. In this stream the strata present the characteristic features of the cement- stones of Ballagan type, and are succeeded by a prominent bed of hard conglomeratic grit. North-eastwards red and green marls are to be found in the Gogar Burn, but between this point and the junction of the Mid-Calder and Murieston faults there are no exposures of strata on this horizon. On the south side of the Cobbinshaw and Dalmahoy syncline the members of this subdivision are laid bare near the head of East Colzium Burn, where the red and grey marls contain cement bands, one of which was sufficiently thick to be quarried for lime. Along the north-west slope of the Pentland Hills exposures of the basal portion of the cementstones are rarely met with, and hence the base-line of the Carboniferous rocks represented on the map is here to a certain extent conjectural. They are laid bare, however, in burns draining into Threipmuir reservoir from the south-east and round the Clubbiedean reservoir, where they resemble lithologi- cally the strata on this horizon in the city of Edinburgh. At the latter locality they contain a marine band, to which reference was made in the previous edition of this memoir.* (6) In the Linhouse Water the band of hard grit at the top of subdivision (a) is followed by red and green marls which pass upwards into purplish, red, and yellow sandstones (b) with a fine brecciated conglomerate containing fragments of the Lower Old Red Sandstone volcanic rocks of the Pentland Hills. This conglomerate, which has been traced to the east of Corston Hill, passes underneath the representatives of the volcanic series of Arthur's Seat. On the south side of the Cobbinshaw and Dalmahoy syncline this subdivision is only exposed in two sections. In the Mid- Crosswood Burn, red and grey sandstones underlie the volcanic zone of Torweaving Hill, and between Harperrig reservoir and Dean Burn there are a few exposures of shaly sandstone and blue shale. J.8.G. W. (c) As already indicated, the lavas and tuffs of Corston Hill point to the existence of a volcanic centre in that neighbourhood which was active about the same period as the Arthur’s Seat volcano and produced a similar suite of rocks, Here again coarsely porphyritic basalts are found associated with fine-grained non-porphyritic mugearites. All the specimens examined microscopically from this area belong to either one or the other of these two categories with a predominance of the *“ Geology of the Neighbourhood of Edinburgh,” Mem. Geol. Sur., pp. 18 and 144, 84 Calctferous Sandstone of Queensferry and West Calder District. mugearite type.* Fuller investigation in the future may prove that some of the rocks, which have been provisionally classed with the mugearites on the ground of their field characters alone, may belong to some other group. Owing to the synclinal structure of this part of the area, the voleanic rocks possess a double outcrop open to the west and con- verging to the east, and in part truncated to the north by the Murieston fault. The greatest development occurs in the Corston area. The local base of the series is exposed in the Linhouse Water, half a mile west of Corston farm, where a mugearite lava rests on a con- glomeratic grit, which in turn overlies a typical development of clays and cementstones. Immediately to the east a porphyritic basalt with conspicuous felspar phenocrysts forms the base of the series for a distance of two miles, and gives rise to the conspicuous escarpment of Corston Hill figured by Sir Archibald Geikie.t The basalt is capped along its course by a succession of mugearite lavas which have been traced farther to the east than the basalt and extend in this direction at least as far as Newlands. The upper portion of the series, consisting also of mugearites, is exposed in the Linhouse Water and in the small tributary from the east in the neighbourhood of Midton. Northwards three lava flows of similar character, separated by thin bands that resemble flow-breccias, but may be true ash deposits, crop out in the railway cutting. A little farther to the west the Murieston Water exposes the top of the volcanic group consisting of a mugearite lava with a ropy and much- involved upper surface overlain by alternations of sandstones and ashes containing fragments resembling the lava. These are in turn overlain by sandstones, dark shales, and ironstone bands. Similar ashes are exposed at a bend of the Linhouse Water a little to the north of the line of the Murieston dislocation. Viewed in connection with the overlying strata, it seems probable that this exposure belongs to a small inlier of the Corston Hill volcanic rocks. This inference is supported by the absence of oil-shales and the Burdiehouse Limestone in this neighbourhood as shown by bores. On the south side of the syncline of which Corston Hill is the northern limb, the voleanic rocks are much less fully represented and are separated by considerable masses of sediment, showing that the volcano to the north had a long period of existence. The lowest volcanic rocks here exposed are- mugearites forming the Torweaving and Black Hills (see Sheet 32). A good example of a slaggy mugearite of this band is seen near the junction of the burns at East Colzium, where it is underlain by an important sandstone with clays and cementstone bands. Near Colzium the mugearites pass under a porphyritic basalt resembling the lowest bed of Corston Hill. At a higher horizon, and separated from the mugearites of Torweaving Hill by sedimentary strata, there occurs an apparently isolated, very slaggy, porphyritic basalt. After another considerable interval, probably occupied for the most part by sedimentary strata, a thick bed of tuff is exposed in the Crosswood Burn resting on. a * Localities from which specimens of mugearite have been obtained and deter- mined microscopically are referred to in Chap. XV. p. 322. t “ Ancient Volcanoes of Great Britain,” vol. i. p. 373. Cementstone Growp—Oil-Shale Group. 85 conglomeratic sandstone. It is overlain by sandstones and shales containing a coal seam that has been proved by boring to be 75 fathoms beneath the “Raw Camps” Limestone, identified with the Burdiehouse Limestone of the Mid-Lothian Coal basin. East of Colzium, the volcanic group is only traceable by means of isolated exposures as indicated on the map by a broken line. The evidence, though very fragmentary, shows that there is a great attenuation of the volcanic products in this direction. B.N. P. (d) The highest members of the Cementstone group in this area are found above the volcanic rocks of Corston Hill in the Murieston Water at Skivo. They consist of fossiliferous grey and black shales with intercalated ash beds and one thin limestone of Burdiehouse type, which dip below thick grey and yellow sandstones with fragments of coal similar to those of Granton. At Little Vantage bands of cementstone with grey blaes rest on coarse pebbly sandstones. In the Green Burn, south of East Newton, light brown and yellow sandstones with a thick cement band dip to S.E. On the north side of Dalmahoy Hill similar sandstones were quarried together with two cement bands, which were burned for lime. On the south side of the Cobbinshaw and Dalmahoy syncline in the Shear and Crosswood Burns, green, grey, and purple sandstones with varying dip are overlain by coarse conglomeratic sandstone con- taining fragments composed chiefly of radiolarian chert. In the Cross- wood Burn this conglomerate was quarried at the foot of the water tower in the Crosswood reservoir and used in the building of the walls that surround this sheet of water. In the Shear Burn a bed of sandstone rests upon this conglomerate, which in turn is covered by a fine, greenish grey, well-bedded tuff, containing fragments of cementstone with plant remains. It probably represents the top of the Arthur’s Seat volcanic zone. A fault with a downthrow to the north repeats this bed at the junction of the Shear and Crosswood Burns. It is not seen to the north of this locality, but the underlying conglomerate has been traced to near Camilty Mull. In the Water of Leith, 400 yds. east of Haugh Head farmhouse, there is a good exposure of a coarse conglomerate with numerous fragments of radiolarian chert and other rocks, similar to the bed already described in the Shear Burn. It is overlain by a bed of ash covered with red and yellow sandstones of considerable thick- ness, and green and purple marls with hard calcareous sandstones. In the burn south-west of Cockburnhill the same ash bed and con- glomerate are again exposed dipping to E.S.E. The ground between Camilty and Wester Causewayend has been pierced by numerous bores, and the strata between these two points may represent the upper portion of the Ballagan beds with several thin coals. THE OIL-SHALE GROUP. The order of succession of the strata composing the Oil-shale group and its important zones are shown in the vertical section Fig. 2 (p. 52). -At present no bands are worked below the horizon of the Pumpherston Shales, though several seams of inferior value occur in the lower subdivisions down to the Granton Sandstone. 86 Calciferous Sandstone of Queensferry and West Calder District. In the economic memoir on “The Oil-Shales of the Lothians” (1906), detailed descriptions with horizontal sections were given of the various shale-fields, which need not here be repeated. It will be sufficient for our present purpose if we select for special reference the. shale-fields of Pumpherston and West Calder and the shore section on the south side of the Firth of Forth, as illustrative of the geological structure and development of the workable oil-shales. The three lowest subdivisions of the group—the Granton Sand- stone, Wardie Shales, and Hailes Sandstone—are not typically repre- sented in this district. In the Murieston Water, the highest members of the Cementstone group are overlain by thick sandstones with pebbly bands, which probably represent the Granton Sandstone. This arenaceous zone contains a thin coal, has a general dip to the south-west, and is repeated bya fault. At Broadshaw Bridge’ these sandstones dip below black and green sandy shales with plant remains which represent the lower portion of the Wardie Shales. These shales and sandstones are repeated by a fault, and, in a short distance, a second . dislocation brings up the sandstone which continues with undulations as far as the bridge across the Murieston Water, about a mile up stream from Broadshaw. In the Shear Burn, a coal seam, six inches thick, associated with fakes and sandstone, occurs 20 ft. above the volcanic ash, and this seam has been proved by boring to lie 75 fathoms below the Burdiehouse Limestone. It has been traced to Crosswood Burn House, where a bore has proved that a second thin coal occurs nine fathoms above it. These coals are probably on the horizon of the thin seam associated with sandstones in the Murieston Water. Between the Linhouse Water and the outcrop of the Burdiehouse Limestone at Harburnhead no natural section is available, but the ground has been extensively bored south-west of Harburn and around Camilty Hill. The lowest beds at Camilty Hill are fakes, blaes, and bands of sandstone with a bed of conglomerate and a limestone two feet thick. At Harburnhead these appear to be covered by a series of blue shales with ironstone bands followed by thick sandstones. Higher up we find a mixed series of fakes and shales with one thin band of limestone, above which come two beds of conglomerate overlain by a succession of blaes and fakes with three thin limestones. Between this horizon and the base of the Burdiehouse Limestone, sandstones, sandy fakes with shales and three thin limestones intervene. This series of strata, about 400 ft. thick, comprises beds from near the base of the Burdiehouse Limestone down probably to the horizon of the Wardie Shales without any representative of the Pumpherston Oil-Shales. AREA SOUTH OF MID-CALDER BETWEEN THE MURIESTON AND CALDER FAULTS. The strata exposed in the Linhouse and Murieston Waters between the Calder and Murieston faults to the south of Mid-Calder lie below the Burdiehouse Limestone. In the Linhouse Water the lowest member is the bed of soft green and yellow felspathic ash which dips to south-east a little below the Oakbank Oil Works. As already indicated, it probably represents the upper limit of the volcanic rocks Oil-Shale Group. 87 of Corston Hill. The ash is succeeded by 300 ft. of thin sandy shales, cementstones, and sandstone bands with plant remains, and these beds may be correlated with the highest beds of the Cement- stone group. These strata dip beneath thick white sandstones with shale and ironstone partings, which are regarded as the equivalents of the Granton sandstones. Before the establishment of the Oakbank Oil Refinery this sandstone group was extensively quarried to within a short distance of the Murieston fault, which is well exposed in the bottom of the ravine and brings the upper portion of the Granton sandstones against the basement beds of the Cementstone group. Just beyond its northern exposure in the Linhouse Water the ash bed is intersected by a fault with a downthrow to the north; but the Granton sandstones, with pebbly bands and a bed of grey limestone with oolitic structure, all dipping in an easterly direction, occupy the stream section to the Calder fault. Between Hoghill and East Langton several trial pits have been sunk, which proved black shale, probably representing the position of the Wardie Shales, in a shallow syncline, and, at the latter spot, the sandstones again rise to the surface. RIVER ALMOND SECTION FROM CLIFTON HALL TO ALMONDELL. From the railway viaduct near Clifton Hall to where the Burdiehouse Limestone crosses the river Almond at East Calder, there is an excellent exposure of the strata for some distance below the Burdiehouse Limestone. Between the viaduct and the bend of the stream below the canal aqueduct a broad band of black shales crops out along the western bank. The bed of the river is occupied by a basalt sill intruded along the bedding planes of the shales, which are burnt. These strata represent the upper portion of the Pumpherston Oil-shale group and dip below shales with ironstone bands succeeded by sandstones with partings as far as the second basalt sill, which lies to the south-east of Ilieston. From this point to the sharp bend in the stream to the south-west of Illieston the section is composed of black shales with ironstone bands and nodules containing fish remains with a few thin beds of sandstone. From the Pumpherston Shale position at Lins Mill to this point, the dip, with the exception of one small fold, is to the west, and here the top of the Pumpherston Shales probably lies 350 ft. below the bed of the stream. In the portion of the river between the bend south-west of Illieston and the ford, flat beds of brown sandstone, shales, and sandy fireclay are seen, and from the ford to the next bend at Drumsboreland Muir no strata are visible. In this part of the river- course the dip must be to the east, for just opposite Almondell the highest oil-shale band of the Pumpherston group appears. This bed sharply rolls over to the west, and there is a steady ascending section as far as the outcrop of the Burdiehouse Limestone to the north of Hast Calder. The lower portion of this part of the section is a repetition of that already described on the east side of the syncline, and the upper portion consists of thick beds of brown, grey, and flaggy sandstones, succeeded by bands of kingle or indurated sandstone, and shales with ironstone and fake partings. 88 Calciferous Sandstone of Queensferry and West Calder District. PUMPHERSTON SHALE-FIELD. One of the most perfect anticlines of the shale measures is the arch of Pumpherston, which brings to the surface the lowest pro- Fic. 7.—Section from Nether Dechmont and Knightsridge to Illieston and the River Almond. Q te s ‘ . S apne* XN ‘Son 7u09 « V = : & gyog FE: 41g SONNOA : NOLSFITI | - = /cN FOI “ VIO SéN F408 [ ~ & te K lH V Salt: el 2 1 Sys ‘ QE 1 : 8 2 ai. Q ‘VIO SONNOA ‘SON FTHOE |* 2 FyOg earth = | SF¥O@IA LN0Gv 007, F uy SoN t ® Ce | t 3 y ! és ss . | 9) = wy0g ke. | Wi FYOI'vVIG = or ; BONY TZHONSWNYG F 9 ty & & x + i A we j S7¥09 éwnya fay] ty wee Td Sd S OdIGN bs! kK = 7Fyog[::: ty y 0 ee w 7 & 7 8 ie 8 / S268 : / a. 5] = / / Ss / ee SIWTOH i 8 G ‘ f/f /6N I¥OG \ 8 ce | { i ly | N 8 = \\ $ V\ \\ S = =A MG ” 3 a \ \N Oil-Shale Group. 89 ductive seams as yet worked in the Lothians. This field is of exceptional geological interest, as it defines the position of the Pumpherston Shales relatively to the Burdiehouse Limestone. The only natural section in this district is the outcrop of the oil-shales and underlying beds in the Caw Burn, but the structure of the field has been thoroughly proved between Powflats and Pumpherston by the numerous mines, pits, and bores which have been driven, sunk, and drilled over this area. Between the Edinburgh and Bathgate Railway and a point to the north of Pumpherston farmhouse the anticlinal axis runs almost due north and south. About 700 yds. to the north of the latter locality the beds begin to pitch to the south, and in the shale workings the inclination reaches an angle of 25° to 30°. Hence the shale outcrops on each side of this fold wheel round rapidly to the south and meet each other about 400 yds. to the north of the farmsteading. On the north side of the Pumpherston Oil Works the beds begin to pitch to the north about 500 yds. from the Edinburgh and Bathgate Railway. At this end of the arch the angle of pitch is low, and hence the east and west outcrops of the five seams forming the Pumpherston Shale group spread out as they bend round the northern portion of this fold. On the west side of the arch the dip of the Burdiehouse Limestone is 45° for a vertical distance of 680 ft. from the surface, and at this point, without any break, the limestone and Barracks Shale become first flat, then gently rise with an easterly dip and appear on the west side of the Houston Wood basin Fig. 7). "oe tig east side of the Pumpherston anticline the dip at first is not so steep as on the west side. Not far below the surface this inclination rapidly increases, and where the strata plunge under the west side of the Clappertion Hall basin, the beds become vertical and for some distance are inverted. Section of Pumpherston Shale-field compiled from Pumpherston Bores. Ft. In. SHALE, BARRACKS .. oa ar ii ye aa ae aaa 7 0 Limestone, BURDIEHOUSE .. 0 Strata—chiefly sandstones, some e of the beds 18 ft. thick, with fakes and thin limy sandstone partings .. 330 0 Strata—chiefly hard fakes and dark blaes with ribs, A few thin sandstone beds intervene .. 126 0 Shaly blaes and thin bands of oil- -shale, ve very inferior quality .. ar 8 0 Strata—chiefly hard fakes and dark blaes with ribs es .- 106 0 Strata—dark blaes, faky blaes with faky sandstone me .. 210 0 O1L-SHALE No, 1, or JUBILEE SEAM ove 2 7 0 Blaes .. es vi “3 “s . 140 O1L-SHaALzE No. 2, or Mayprick Sram - a a sii 28 5 3 Blaes and balls with ribs ah i nr ab ab . 6} O1t-SHate No. 3, or Curty Szam isi ua as is us 7 5s Fakes and blaes. . é : a bis ea Par .- 22 0 O1t-SHaxz No. 4, or Prarn Seam sn 23 ve es 7 8 Blaes ie oe : 2 8 OI-SHALE .. 15 Blaes with ribs . 5 10 90 Calciferous Sandstone of Queensferry and West Calder District. Ft. In. O1n-SHALE No. 5, “ WEE” or UNDER SHALE 4 3 Dark and sandy blaes with fake ererete 32 6 Shaly blaes .. 1 8 Hard dark blaes 2 4 Shaly blaes .. i 3.64 Blaes and balls .. 5 6 Shaly blaes fe 1 8 Dark blaes 3 10 Shaly blaes .. 4 8 Dark blaes and balls 10 0 Soft blaes with ribs ll 9 Grey fakes ate se 110 Marl and marly fakes .. 41 0 Grey fakes with ribs 25 6 Hard grey. sandstone 7 8 Grey sandstone . 15 6 Hard sandstone and limy fakes 12 0 Grey sandstone and limy bands 21 8 Marl, grey and dark 3 8 0 Dark blaes fa fe 26 os 31 Fakes and blaes with sandstone and limy ribs sa i wm 12 4 Hard grey sandstone 1 0 Blaes and ribs .. : 3 4 Grey sandstone fakes and ribs 7 0 Blaes and grey sandstone ribs. . 6 0 Grey fakes with limy and sandstone ribs 8 0 The above section shows that beneath the Pumpherston Shales 250 ft. of strata have been proved by boring. The lower portion of these beds consists of thick grey and hard sandstone with some beds of shales, fakes, and grey marl. It is possible that this siliceous series may represent the higher portion of the Hailes Sandstone. These beds are overlain by a thick bed of marl and marly fakes, and between this and the lowest shale (No. 5) of Pumpherston there are four separate beds of shaly blaes. Pumpherston Shales.—These shales comprise a group of five work- able seams and are remarkable for their richness in ammonia, the yield with the best form of retorts being from 50 to 60 pounds of sulphate of ammonia with 20 gallons of oil per ton. The plain portion of No. 3 seam below the “curly” part has furnished a large number of well-preserved fossil fishes determined by Dr. R. H. Traquair, F.R.S.,and the shale below the “Wee” band or No. 5 Oil-Shale contains well-pre- served plant remains which have been named by Dr. R. Kidston, F.R.S. None of the Pumpherston seams is worked at present on the south, east, or west sides of the anticline, but at the north end all the beds, with the exception of the Maybrick, are worked by the Broxburn Oil Company at the Roman Camp Mines. This company has driven a mine from the south side of the Edinburgh and Bath- gate Railway in the direction of Powflats, which intersects the large east and west dolerite dyke. These shales have been proved by boring to lie to the north of Powflats and probably extend as far as the Middleton Hall fault. To the east and north-east of Pumpherston this shale group and two basalt sills which lie at the top and bottom of this series have been proved by diamond bores at Illieston. The highest of these intrusions is exposed in the bed of the river Almond, and both have rendered the shales useless. The Pumpherston Oil Company put down a series of bores during Oil-Shale Group. 91 1905-6 by the hand rig diamond boring machine between the Burdiehouse Limestone and the Pumpherston Shales. These showed that for 200 ft. above the shales the beds consist of dark faky shale with oil-shale streaks and faky sandstone partings, which are succeeded by over 200 ft. of hard fakes and dark blue shales with ribs or “kinglestone.” Near the centre of this series, or 456 ft. below the Burdiehouse Limestone, lies a band of fissile shale 8 ft. thick, with thin plies of oil-shale of very inferior quality. For 330 ft. below the Burdiehouse Limestone the strata are chiefly sandstones, some of the beds attaining a thickness of 18 ft. The Burdiehouse Limestone is not exposed around the Pumpherston anticline, but its position has been defined by numerous bores, and on the west side of this fold it is about 20 ft. thick. » WEST CALDER SHALE-FIELD. The West Calder shale-field includes the area that is bounded on the east by the Murieston fault and on the west by the outcrop of the Hurlet Limestone. It displays the sequence of workable oil- shales from the Burdiehouse Limestone to the base of the Car- boniferous Limestone series, as shown in the subjoined table. General Section of West Calder Shale-field. Hurwet LIMESTONE AND Coal. Ft. In. Strata—blaes, ironstone ribs, thin coals, with bands of as sand- stones .. Be ae ae a 256 450 0 RazEBURN SHALE ; a 911 Strata—blaes, fireclay, fakes, and ironstone bands, 126 ft. to .. 150 0 Muneue SHAtgs, 1 ft. 7 in. to ‘ a fee 2 0 Strata—blaes, fakes, fireclay, and ironstone bands .. ee .. 1380 0 Two-Foot Coat, 7 in. to oe i Ae ms ee ais 1 2 Strata—104 ft. to “% ed 2 eA i ay .. 280 0 Grey SHALE .. 5 5 ns fi ae 1 8 Strata—fireclay, with blue partings a ns 525 ee .. 73 0 Houston Coat in bands, 4 ft. to .. 6 0 Strata—thin laminated andes, dark k flaky blaes, and clayband : ironstones, 150 ft. it 200 0 Friis Sane, 2ft.6in.to .. wh a ie ie re 7 0 Strata—Broxburn Marls, 250 ft. a Be is a .. 275 0 BROXBURN SHALE, 4 ft. to .. oe is os 6 0 Strata—including Hermand or Binny ‘Sandstone Bs -. 420 0 Dunnet SHALE, 6 ft. to Pr “3 8 ie as és . 10 0 Strata ae sit 2s te is bs as a .. 52 0 SHALE (New ?).. 4 6 Strata—green felspathic sandstones, with conglomerate bands and shale partings, about . See ne on oe ai -. 600 0 Barracks SHALE iA : a wh we a a oF 4 0 BurRDIEHOUSE LIMESTONE .. 43 s ws 3 vs .. 40 0 The accompanying horizontal section (Fig. 8) is drawn across the northern portion of the West Calder shale-field from Limefield Mains in the east to Addiewell Bridge in the west. It shows the low anticlinal fold which brings the Broxburn Shale to the surface close to West Calder. To the north-east and north-west of the village the strata lie in a series of shallow synclinal folds, while to the west - the upper seams have a general westerly dip, and, after a series of gentle undulations, pass under the overlying Hurlet Limestone. 92 Calciferous Sandstone of Queensferry and West Calder District. &= —Ww33s LIMEFIEL DO +—wlE3an— HERMANO WCALDER BREICH MILL AODIEWELL MAINS HO. BRIDGE 2000 FEET 500 1000 o SEA LEVEL Fic. 8.—Section from Addiewell Bridge to Limefield Mains. Burdiehouse Limestone. — On _ the east side of this field the Burdiehouse Limestone, 40 ft. thick, is exposed in the railway cutting at Blackmire, It is a typical freshwater limestone, and is overlain by 500 ft. of strata com- posed of green felspathic sandstones with fine conglomeratic bands and shale partings. The limestone is re- peated by a north-easterly fault, and crops out in the Harwood Water above Limefield House with the Bar- racks Oil-Shale from four to six feet thick. Dunnet Shale-—In the Harwood Water 600 ft. of siliceous strata with beds of green and red marls separate the Burdiehouse Limestone from the Dunnet Shale. There is an excellent exposure of this seam in the stream to the north of Hermand House, where it is covered by the characteristic Dunnet Marls. In a mine to the north, this shale shows the following section :— Roof, shaly blaes. Ft. In. SHALE, plain - 44 » curly .. 2 0 » Plain . 2 8 9 0 Pavement, blaes. Binny Sandstone—The Dunnet Shale is succeeded by the Binny Sandstone, about 400 ft. thick, which consists of thick beds of sandstone resting upon and overlain by black shales with iron- stone and faky bands. In the Broxburn district these shales are represented by marls. Broxburn Shale——The outcrop of the Broxburn Oil-Shale is not seen in the Harwood Water, but in a mine near Chapelton the following is the measured section :— Ft. In. SHALE (top) 0 5 Blaes 0 10 Fake 0 ll SHALE (good) 3° ¢67 Rib, blue 0 6 SHALE (bottom) .. Oo 8 6 i Pavement, fireclay. Oil-Shale Group. 93 A glance at the map shows that this shale comes to the surface to the south-west of West Calder upon the centre of an elongated anticlinal fold. This portion of the Broxburn seam has been recently opened out. At first it proved irregular, but when followed to the dip the quality of the oil-shale improved. These shales have always been of an inferior quality in the West Calder district. The average thickness of the Broxburn seam is generally less than three feet with a yield of about 20 gallons of oil per ton. Tn the district around Burngrange several bores proved a coal, two iuches thick, beneath the shale. Broxburn Marls—The Broxburn Marls, estimated to be 250 ft. thick in this district, are not exposed in the northern portion of the West Calder field, but on the south side of the Calder fault there is a good section of them in the Harwood Water just above the point where the stream is crossed by the West Calder and Harburn road. Here the beds are chiefly bluish and greenish grey shales and marls, with numerous bands of shaly sandstone, alternating with ribs of hard cementstone, which vary in thickness from one to three feet. Towards the top of these marls, shales with ironstone bands occur together with a bed of coarse dark lime- stone, yielding Lepidodendron, fish scales, and entomostraca. At the top of these shales lies the well-known cream-coloured un- fossiliferous limestone which constitutes the index to the Fells Shale. Fells Shale—To the north-east of West Calder this seam fills a shallow basin towards the centre of which there are several faults which proved very troublesome to mining operations in the past. North- west of the village another basin has been largely mined, where this seam, about four feet thick, was found to consist of soft and hard bands. Here the Fells Shale has been worked across an anticlinal ridge which does not bring the shale to the surface. The flexure is accompanied by a want and several minor folds. No information has been obtained regarding the area to the south-east of West Calder, and the shale outcrop as shown on the map is there indefinite. The Fells Shale, known in the early stages of the oil-shale industry as the “Thick Shale of Addiewell,” has always been the principal oil-producing seam in the West Calder district. It varies from 24 to 34 ft. in thickness, but in some portions of the field reaches 7 ft. In sinking a pit to this seam near Blackbrae, a fossil tree was found standing erect, which was 20 ft. in length, and at the base measured 18 in. in diameter. The centre of the fossil was sandstone, and the outer portion consisted of carbonised wood. Houston Coal. section in the West Calder Burn, south of Burngrange, shows that thin laminated sandstones with shale partings separate the Fells Shale and Houston Coal. A pit sunk to the oil-shale 25 yds. to the west of the coal crop reached the shale at 32 fms., and, allowing for dip and rise, the vertical distance between shale and coal is 150 ft. On both sides of the Breich Water this coal was at one time extensively worked along its outcrop between the Blackbrae and Mid-Breich faults, Its general thickness was about six feet with 94 Calciferous Sandstone of Queensferry and West Calder District. one foot of stone in the centre. At Gavieside the coal has the follow- ing section :— Roof, fireclay. Ft. In, CoaL a2 ze es .. O 6 Coat and blaes 0 4 Coan F 0 7 Parting 0 0% CoaL 8 1 2 Mudstone 0 9 Coan a8 1 2 Parting 0 1 CoaL ‘ 1 0$ 5 9 Pavement, fireclay, Grey Shale.—In the West Calder Burn 73 ft. of strata, composed of beds of sandstone with fireclay and shale partings accompanied by two thin coals, separate the Houston Coal from the Grey Shale, This bed, 1 ft. 8 in. thick, is almost entirely composed of entomos- tracan remains. Houston Marls.—The Grey Shale forms the base of these marls, which vary in thickness from 104 to 230 ft. A section of these beds is exposed in the Breich Water above Breich Mill, and here the marls and blaes contain numerous seams of ironstone from 2 to 4 in. thick. Two-Foot Coal—Above the Houston Marls lies the Two-Foot Coal, with a sandstone roof and fireclay pavement, which has never been wrought in the West Calder district, but in a bore at Westwood it shows the following section :— Roof, sandstone. Ft. In, Coat, coarse splint... . 010 » cherry 0 8 » coarse 0 6 2 0 Pavement, fireclay. Two feet appears to be its maximum thickness, for in the Breich Water it measures only seven inches, and is there covered by black shale with several seams of good clay-ironstone. -Next in order comes a series of shales, fakes, and fireclays with a few thin beds of sandstone, and in the upper portion of this group there are numerous bands of ball ironstone with dark shales and fireclays. From the Blackbrae fault the outcrops of this seam and of the Houston Coal trend generally N.° 10° W., but to the S..W. of Mid-Breich a shallow synclinal fold carries both these outcrops for some distance to the south-west. The thickness of strata between the Two-Foot Coal and the Mungle Shale is estimated to range from 130 to 180 ft. Mungle Shale—This seam varies in thickness from 20 in. to 2 ft., and was worked by shallow pits on both sides of the Breich Water, near Addiewell; About 120 ft. of shale with ironstone Oil-Shale Group. 95 ribs, fakes, and fireclay lie between this seam and the Raeburn Shale. Raeburn Shale—In the early stage of the oil-shale industry in the Addiewell district the Raeburn Shale was known first as the “Dam Shale,” and afterwards as the “Upper Shale of Addiewell.” These are now correlated with the Raeburn Shale. Roof, blaes. Ft. In SHALE, curly 1 8 », plain 0 9 Fireclay 0 3 Blaes 0 5 SHALE 0 3 3.4 Pavement, fireclay. A section of this seam is given in the memoir on “ The Oil-Shales of the Lothians,” p. 24. The one above is from the same locality, and shows a slight difference in the sequence. In the river Almond, on the west side of Hopefield Mills, a bed of ash lies a little above the Raeburn position. The Raeburn Shale and the Hurlet Coal are separated at Addie- well by 75 fathoms of strata, which consist of shale with ironstone ribs, several thin coals, a freshwater limestone, and a few beds of sandstone, some of them coarse and pebbly. The freshwater lime- stone, which lies about 120 ft. below the Hurlet Coal, is exposed on the south bank of the Breich Water below Addiewell Bridge in two leaves, the largest not more than one foot thick,accompanied with coaly blaes. At South Cobbinshaw a bore close to the reservoir passes through two thin limestones and a coal, 150 ft. below the Hurlet Coal. In the river Almond the strata between the Houston Coal and the Raeburn Shale are not seen east of the bridge south of Hope- field Cottage, and this gap is estimated to contain 430 ft. of strata. About 300 yds. west of this bridge, and about 100 ft. vertically below the Hurlet Limestone, there is a marine limestone, one foot thick, with abundant remains of encrinites, which is underlain by an inferior oil-shale with ironstone bands, and overlain by sandstones. SHORE SECTION BETWEEN WHITEHOUSE POINT AND MIDHOPE BURN. The coast section between Whitehouse Point and Midhope Burn at Abercorn is the best natural exposure of the oil-shale measures of the Lothians. It begins with strata 500 ft. below the Burdie- house Limestone, and shows the sequence of the beds upwards to the base of the Broxburn Marls. Between Whitehouse Point and Port Edgar there is a compar- atively shallow basin two miles broad, in the centre of which the strata form a compound syncline with the Broxburn Marls as the highest beds. On the west limb of the compound fold South Queens- ferry is situated. From Springfield to Banks the strata fold over a very flat anticline, and near Society they pass into a deeper synclinal fold, which, for descriptive purposes, is called the Duddingston basin. West of this point is the well-marked Hopetoun anticline with its centre near Hopetoun House, whose eastern limb is steep, and 96 Calciferous Sandstone. of Queensferry and West Calder District. “JUIOg asnoysyIyM 04 Ung adouprnt WOIJ 9LOYY VY} SuoTe uoT9G—‘G “DIY 77 700 eae % fa o §& - & aw SS ac = = RP S oe Jo) TRS Se ta, Sf oR BEA Sf bE GS SRS ; RY S5 4 $9 x De ee & os SG se F% : : 2 = 2s ay md N ss 2 Q 6 “N m 4 22 om YR sa7pwmen S2 LNIOP ; m * yooue YPIGI LYOd xS ANY ‘FSNOHILIAM ~ HL¥0d = AYYFASNTING SN ows <—'S9oIFI ~~ NNOLIAON | er eae aes rt mao | LIFI OOO O00/ OOS Oo TIAIT VIS ‘On nung SYNVG ALWIOS NIOLIAOH = =FTLSYZTAOHGIN - <—"SI'FI|NOZM> —SOZ7|SSM> «NSF \NSEM—> —'sgez \ Oil-Shale Group. 97 the western, after undulating gently for some distance, maintains a steady dip to the mouth of the Midhope Burn where the rock section terminates. a fea At Whitehouse Point the beds above the intrusive sill of Mons Hill are estimated to lie 555 ft. below the Burdiehouse Limestone. These consist of greenish grey shales, which, after a considerable gap, are succeeded by beds of sandstone, on one of which stands Long Craig Pier. Above these sandstones lies a band.of oil-shale, 6 ft. thick, whose position is calculated to be 90 ft. below the Burdie- house Limestone, which at this point forms the “Long Rib,’—a conspicuous reef on the shore section. Here it is a:cream-coloured rock, 7 ft. 10 in. thick, with a thin parting of bituminous blaes, which dips to the west at an angle of 45°, but this high inclination is not maintained -for any distance as the beds soon resume their normal dip of. 15° to 20°. . The Burdiehouse Limestone here rests on limy and bituminous blaes with a curly oil-shale of good quality, and in the past it was quarried both on the shore and at New Gardens, Next in order come bituminous and alum shales, 144 ft. thick, followed-by 114 ft. of oil-shale. The top and bottom of this oil-seam are particularly rich, the upper portion containing strings and pieces of bitumen. It is succeeded by 78 ft. of black bituminous shales with thin limestone and ironstone bands overlain by an oil-shale, 8-ft. thick, with a calcareous roof. These two oil-shales above the Burdie- house Limestone are of excellent quality and may be correlated with the Barracks Shale. The upper oil-shale is surmounted by a thick sandstone series followed by three thin limestones associated with faky shales and bands, Dunnet' Shale—This shale together with its characteristic marl appears immediately below the Forth Bridge, but the section is partly obscured by a small fault. It is computed to lie 341 ft. above the Burdiehouse Limestone.* Binny Sandstone Series—Above the Dunnet Shale come 300 ft, of brown, white and yellow sandstones —the local representa- tives of the Binny Sandstone series. On the west side of the Queensferry basin near Port Edgar these sandstones were at one time extensively quarried for rubble work, and, on the shore to the west of the town, an impure calcareous band about four feet thick forms part of this series. A similar band is found in the West Calder district at this horizon. As already mentioned a compound syncline occupies the centre of the Queensferry basin, and at the “The Craigs,” midway between the pier and Newhalls, is situated the anticlinal axis which separates the two synclinal folds. Broxburn Shale. —This shale rests on the Binny Sandstone series, and is exposed on the shore just below the east wall of Queensferry harbour, and also on the opposite side of the west synclinal fold near the church. Here it is 7} ft. thick, but inland in the railway cutting it measures 9 ft. _ Dunnet Shale——This shale is not visible on the west side of the Queensferry basin, but it is probable that its outcrop lies on the, west side of the slip pier inside Port Edgar, and runs south-east as indicated on the one-inch map. a *For details see Vertical Section, Whitehouse Point to South Queensferry, “ The Oil-Shales of the Lothians,” Mem. Geol. Sur., p. 74, 7 98 Calciferous Sandstone of Queensferry and West Calder District. Barracks Shale——The railway section begins at Port Edgar about twenty feet above the Burdiehouse Limestone with bituminous shales intersected by a thin “white trap” dyke. These bituminous bands represent the position of the Barracks Shale, and are succeeded by black shales with thin limestones and ironstone nodules. Next in order comes a grey calcareous sandstone, 18 ft. thick, overlain by black shales with cement ribs. These beds above the sandstone dip north-east at an average angle of 14°, and in the cutting are 275 ft. thick, so that the Dunnet Shale position must lie a short distance to the east of this rock section. A considerable difference is observable between the lithological characters of the strata on the west side of the Queensferry basin and those on the east side from the Forth Bridge to the “ Long Rib.” In the latter section nearly one-third of the sediments is siliceous while in the railway section the proportion is one-seventh, which clearly indicates shallow water conditions on the east side and deeper water sedimentation on the west. Burdiehouse Limestone.—On the west side of Port Edgar is situ- ated the outcrop of the Burdiehouse Limestone, formerly mined between the shore and Echline. These workings were known as the Dundas Limework, and the seam varied from six to nine feet, was dark in colour, and contained some iron. It formed three beds dipping to E.N.E., and was crossed by a dyke of so-called “ sandstone conglomerate” divided in the centre by a vein of spar containing galena. West of the outcrop of the Burdiehouse Limestone for about 200 yds. no rock is visible on the shore till sandstones with an easterly dip appear at the junction of the two roads. This gap is quite sufficient to contain the strata, together with the two oil-shales, which occur below the limestone on the east side of the Queensferry basin. The sandstones at the two roads overlie a dolerite sill of no great thickness, and dip first to east and then roll over at a gentle angle to the north-west. From the mouth of the Linn Mill Burn to a point south of the Hopetoun sandbank these sandstones, which are there about 200 ft. thick, form the eastern limb of the Duddingston basin, and they probably represent the beds at Long Craig Pier east of Queensferry. South of Hopetoun bank they are overlain with beds of bituminous shale and pass beneath the Burdie- house Limestone. Beyond these sandstones, on the shore north-east of Banks the Burdiehouse Limestone occurs in three leaves, is of the dark type and weathers with a bright yellow ochreous coating. Above the top bed there is a gap representing 8 ft. of vertical thickness, which has the appearance of being quarried, but, if limestone beds have not been removed, it may represent the position of the alum shale on the east side of the Queensferry basin. Above this gap comes the Barracks Shale consisting of 104 ft. of mixed oil-shale and blaes. To the N.N.E. of Banks a calcareous sandstone crops out on the shore, and between this horizon and the Burdiehouse Limestone 225 ft. of strata occur, chiefly composed of beds of sandstone. At this point a small strike fault, with a displacement to the west, probably throws down the Dunnet Shale which will account for its absence in this part of the coast section, Oil-Shale Group. 99 Binny Sandstone Series—Between the calcareous band N.N.E. of Banks and the west end of Society village, ripple-marked sand- stones with carbonaceous streaks occupy the shore section, At first these beds dip west, but after minor undulations they incline in an easterly direction near Society. In this portion of the section they surround a small oval-shaped mass of a dark greenish felspathic agglomerate, which, from its mode of occurrence, probably represents an ash neck. Dunnet Shale—At Society the Dunnet Oil-shale lies at the base of the Binny Sandstone, where it is separated into two beds, each about 5 ft. thick. The lower of the two is of excellent quality and rests upon a black carbonaceous ironstone full of fish remains. Dunnet Marls—tThe top Dunnet Oil-shale has a calcareous roof covered by 22 ft. of shale succeeded by 30 ft. of marls with limestone bands—representing this horizon. In 1901 the landward outcrop of the Dunnet Shale was proved by the Dalmeny Oil Co., and was found to follow very closely the old quarried outcrops of the Burdiehouse Limestone on the west side of the Duddingston basin. A diamond bore drilled to the north of Crawstone near the centre of this basin passed through the Binny Sandstone, and at 324 ft. proved the Dunnet Shale to be 12 ft. thick ; it further proved at a depth of 570 ft. from the surface the Barracks Shale and the Burdiehouse Limestone below.* The Dunnet Shale on being tested yielded 274 gallons of crude oil and fully 35 lb. of sulphate of ammonia per ton. On the shore section already described, the beds which separate the Burdiehouse Limestone and the Dunnet Shale on the east side of the Duddingston basin are chiefly yellow and white sandstones estimated to be 225 ft. thick. But in the Crawstone diamond bore a great change takes place in the strata above the limestone. This bore is only 700 yds. from the shore, and its record shows that the sandstone beds are represented by limy fakes and blaes in the proportion of 1 to 5 in a total thickness of 221 ft. The measured shore section on the west side of the Duddingston basin, and on the east limb of the Hopetoun anticline, extends 425 yds. to the west of Society and nearly reaches the centre of the Hopetoun arch.t On the shore the thickness of strata between the Dunnet Shale and the Burdiehouse Limestone is estimated at 343 ft. as compared with 221 ft. in the Crawstone bore. Here again there is a remarkable difference in the nature of the strata intervening between these two horizons. On the coast section three-fourths of the beds are composed of siliceous materials and the remaining portion of argillaceous sediments. In the Crawstone bore the proportion of these two types of deposit is reversed. This differ- ence of sedimentation within so short a distance, when viewed in connection with the change already noted in the beds above the Burdiehouse Limestone at Port Edgar, is worthy of note, as it indicates a rapid alternation between shallow and deeper water conditions within a very limited area. These shore * For details of section in the Crawstone diamond bore, see ‘“‘ The Oil-Shales of the Lothians,” Mem. Geol. Sur., p. 80. + For details regarding the Shove section on the east side of Hopetoun anticline, see op. cit. p. 81. 100 Calciferous Sandstone of Queensferry and West Calder District. conditions are more highly developed to the north and east, and point to a limitation of the oil-shale deposits in these directions. Towards the base of the sequence on the east side of the Hopetoun anticline there is an intrusive sill of white or yellowish igneous rock, 6 ft. thick, in two sheets with soft blaes between, which has cavities full of bitumen, like those noted in the Broxburn section. If this intrusive mass is the same as that exposed at the mouth of the Linn Mill Burn, it here occupies a slightly lower position. Below. the sill on the Hopetoun shore we find about 50 ft. of shale, bituminous shales, and 8 ft. of-a hard black limestone with worm tubes, which, when dissolved in hydrochloric acid, is found to be rich in lime. It evolves a considerable quantity of sulphuretted hydrogen gas, and leaves a fine black carbonaceous residue, From Society village to a point above the black limestone all the strata dip steadily to east, but where this bed appears the direction of the dip changes slowly to west by north. Hence the axis of this fold i is well defined. ’ The limestone charged with worm tubes lies 259 ft. below the Burdiehouse Limestone, and beneath it come shales with oil-shale and’ cement bands, which graduate downwards into shales with hard ironstone bands. These are the lowest beds exposed on the eastern limb of the Hopetoun anticline, and their position is calculated to be 342 ft. below the Burdiehouse Limestone. On the west side of the Hopetoun anticline* and a short distance above the worm tube limestone, the sill with bitumen is seen resting on a few feet of oil-shale of inferior quality. For 100 yds. across the strike the shore is covered with mud, and the first beds seen are shales with bands of oil-shale and thin limestones. Calcareous shales with limy bands separate these from the Burdie- house Limestone, 32 ft. thick, which has here a brecciated and flinty base, while its upper portion is a dark limestone full.of plant and fish remains. Several minor folds carry the bed along the shore for 150 yds. just below high-water mark, where it resumes its normal strike and passes inland on the west side of Hopetoun House. Scattered heaps of debris on this part of the shore indicate where the Burdiehouse Limestone has been quarried, and beyond these heaps the Barracks Shale, 10 ft. thick, mixed with sandy shales, crops out on the shore. Westwards a good many gaps occur with sand- stone beds at intervals till the Dunnet Shale is reached, which is well exposed on the shore to the E.N.E. of the old Castle of Abercorn. It is a rich band, 16 ft. thick, and contains plant remains. Binny Sandstone.—Yellow and grey faky sandstones with several gaps represent the next 308 ft. of strata, and on a sandstone pavement rests the Broxburn oil-shale. Broxburn Shale——This seam, 16 ft. thick (with a thin cement parting), contains entomostraca together with abundant fish remains. The roof consists of a dark limestone, 1 ft. thick. Next in order come 60 ft. of calcareous and siliceous beds (with gaps) which probably represent the Broxburn marls. A succession of false-bedded, flaggy sandstones, 138 ft. thick, completes the section to the Midhope Burn. JS. GW. * For details regarding the shore section on the west side of the Hopetoun anticline, op. cit. p. 83. Oil-Shale Group 101 DRUMCROSSHALL TO WESTER OCHILTREE. From Drumcrosshall the crop of the Houston Coal trends in a north-easterly direction and, after being thrown by a fault towards the west near West Bangour, runs towards the north. In draining a field half a mile west of Blackcraig, the coal crop, together with the overlying Houston marls and Two-foot Coal, was found running obliquely up the slope of the hill in a N.N.E. direction. From here the crops, together with that of the ash above the Two-foot Coal, swing round to the east and then back again to N.N.E. just before they reach the Uphall fault. Beyond the fault the crop is shown by old workings as far as the Ecclesmachan fault, which throws the crop some distance to the west. The old erop workings are again seen in the neighbourhood of Wester Ochiltree. An excellent section of the ash above the Two-foot Coal is exposed in the Brox Burn below the reservoir for the Bangour Asylum. The ash is succeeded by blaes with bands of bituminous shale and some sandstones. Above the latter there follow a green ash and then the basaltic lavas, which are a southward prolongation of the Riccarton Hills basalts. H. B. M. WESTER OCHILTREE AND KINGSCAVIL DISTRICT. The Fells oil-shale is not seen to the west of Wester Ochiltree but. it probably occurs on both sides of an anticline that repeats the Houston Coal, a seam which was formerly worked in a basin to the east of Wester Ochiltree, but details of the old workings are not available. Towards the west the outcrop of this coal is fairly well defined by old crop workings; it runs through a plantation 540 yds. W.S.W. of Wester Ochiltree and can be traced running slightly east of north as far as the Haugh Burn alluvium, after which it is not seen again south of Kingscavil. On the east bank of a stream south of the road, half a mile west of Wester Ochiltree, the Two-foot Coal was sought in a. trial hole. On the west bank a low cliff shows several feet of dark carbonaceous shales containing cyprids and coprolites of Rhizodus (?), At. the junction between these shales and the bed of ash above, there is a good deal of disturbance, as is usual near boundaries of different texture. The thickness of this ash is not less than 50 ft. Search has evidently been made for the Two-foot Coal below, but with what success we do not know. The tuff can be traced northward to the Haugh Burn, being seen 600 yds. east of Riccarton, whilst another trial hole to the coal is seen close by; the outcrop then swings round, bearing N.N.E. and is seen once more in a stream passing through a wood 450 yds. south of Haugh Burn; some oil-shales farther down this stream may occupy the position of one of the upper seams. North of Haugh Burn, neither shales nor coals are recognised, anda large fault proved in the Champfleurie workings perhaps traverses part of this ground and shifts the outcrops to the ‘east on its northern side.. : : At Kingscavil Quarry—in beds lying between the Two-foot Coal 102 Calciferous Sandstone of Queensferry and West Calder District. and the base of the Carboniferous Limestone series—the following section is seen :— Ft. In Boulder clay si it sis i 2 i Broken sandstone . . as aa 2 . 6 0 Dark shales with septaria aie is ws .. 15.0 Sandstone, oe at base. . a e ss .. ll 6 Blue shale .. Si es bs se B10 Coat... 7 #¥ sb bs . 0 6 Sandstone, 1 main bed ai i Es 2G .. 50 0 Sandy shales i es we ee i eee bY North of Park some borings were made in 1897 in search of this sandstone, and another of earlier date in the same locality passed through a bed of sandstone 76 ft. thick, but with too many thin partings to be workable. Above this, a coal is said to have been found while making the foundations of the canal bridge. The strata between the Houston Coal and the limestone at Carsie Hill *—-which is taken as the base of the Carboniferous Limestone series—appear to be mainly arenaceous, but some thin bands of limestone also occur, the chief of which is exposed 400 yds. up the Riccarton Burn, and consists of a thin lower bed and an upper one, 34 ft. thick, separated by an obscure interval in which there is room for 5 or 6 ft. of strata which are not seen. Brachiopods occur in the upper bed. Fragments of a similar limestone were obtained from an excavation at Riccarton, but we are not justified in supposing this bed to be the limestone which occurs in the stream, repeated by faulting and folding. Calcareous bands occur among the sediments seen in the vicinity of the necks 900 yds. slightly east of north from Riccarton. It is on this calcareous horizon that the first lavas (Longmuir Plantation group) are seen 800 yds. south of Riccarton, and above these, in the stream 200 yds. south-west of the road, a remarkable breccia of siliceous character is found; the fragments are angular and are either hard and sandy, or soft—the latter may be white trap. This breccia may possibly have some connection with the early eruptions or it may be a crush breccia belonging to some fault of small size. Of the rocks between the northward prolongation of the Riccarton Hills lavas and the line chosen as the base of the Carboniferous Limestone series, we have little evidence; 300 yds. south of Whitebaulks a sandstone is seen on the road, and it is stated that coal has been obtained in small quantities near this spot. This appears to be the seam underlying the limestone at Whitebaulks. G. W. G. BLACKNESS AND KINGSFIELD AREA. In this area, extending along the south side of the Forth from Blackness westward to the neighbourhood of Stacks and inland to Kingsfield, no rocks are exposed except along the shore on the west side of Blackness Bay, in small outcrops on the present beach. Among them is a limestone, compact and creamy with occasional pink blotches, which weathers into small knobs and seems to be about two feet thick; it appears to contain no fossil remains except some obscure rootlets, and is perhaps of fresh-water or estuarine * Carsie Hill is not marked on Sheet 32; it lies 380 yds. east of Cauldhame. Oul-Shale Group. 103 origin. It somewhat resembles the limestone at the Limekilns Golf Course, on the north side of the Forth, which is estimated by Mr. Maufe to be perhaps 160 ft. below the bed taken as the base of the Carboniferous Limestone series in that locality. Both a little above and a little below the Blackness Limestone soft yellow false-bedded sandstones occur; the lower is probably at least 40 ft. thick and is underlain by dark grey shales and flaggy sandstones. The beds described have a north-easterly dip, but, a little distance west of the exposures, they probably roll over and dip north-west beneath the beds referred to the Carboniferous Limestone series. A boring, the position of which is supposed to be about a quarter of a mile S.S.E. of Cauldcoats, pierced an impure limestone which may possibly represent the Blackness bed. It is 3 ft. 5 in. thick, including a shale parting in the middle, and was met at a depth of 26 fms. from the rock surface. The journal of another bore, the position of which is about 400 yds. W.5.W. of Merrylees, records a depth of more than 49 fms., and a considerable thickness of marls which may be the Houston marls. The rocks first met with probably belong to a position considerably below the Blackness Limestone. They consist of sand- stones and fakes, together more than 14 fms. thick, and may ‘possibly represent the thick sandstone quarried near Pardovan. Cc. T. ¢, CHAPTER IX. CARBONIFEROUS LIMESTONE SERIES OF THE COBBINSHAW, BATHGATE, BO'NESS AND: CHARLESTOWN DISTRICT. ‘THs district comprises a narrow belt of country extending from Cobbinshaw and Addiewell in the south to Bo'ness and Carriden in the north, together with a small area on the north side of the Firth of Forth at Charlestown and Limekilns. The portion of the county of Fife that projects southwards into Sheet 32 was not included in the scheme of revision of the Carboniferous Rocks of the Lothians, as .the geology of that area was described by Sir A. Geikie in the memoir -on Central and Western Fife. But the adoption of the West Kirkton and Tartraven Limestone as the representative of the Hurlet Lime- stone necessitated the re-examination of the shore section west of Rosyth where the Petershill Limestone had been mapped as the basal member of the Carboniferous Limestone series.* The three groups of the Carboniferous Limestone series, together with various details regarding their development in this district, are given in the subjoined table— 3. Upper Limestone group, with three or four thin marine limestones and some thin coals, Near the Forth it appears to be more than 800 ft. thick, but farther south it becomes much thinner. At Hilderston, rather more than three miles north of Bathgate, it is only 446 ft., even with the inclusion of a considerable thickness of igneous rock. 2. Bo’ness and Bathgate Coal group. A thick series of sandstones and shales with valuable coals corresponding to the Edge Coals of Mid-Lothian. The thickness, including volcanic rocks, near the Forth, amounts perhaps to 950 ft. At and a little south of Bathgate, in an area where the volcanic rocks are not quite so well developed ‘as near the Forth, the thickness is about 750 ft. 1. Lower Limestone group, with various marine limestones, some of which are of considerable thickness. In the Bathgate Hills, where the volcanic rocks are strongly developed, the thickness is perhaps nearly 1000 ft. Near the Forth the group is almost free from volcanic rocks, and its thickness is probably not much more than half this amount. In the Cobbinshaw and Addiewell district, also, it cannot much exceed 500 ft. The character of the series as a whole differs remarkably from that in Mid-Lothian owing to the intercalation of great thicknesses of igneous rock with the sediments. Near Linlithgow, and for four or five miles to the south the igneous rocks are so largely developed that the Bo'ness and Bathgate Coal group is of little or no economic value. We shall now proceed to describe the different rock-groups in detail, taking first the Lower Limestone division, and advancing from *“The Geology of Central and Western Fife and Kinross,” Mem. Geol. Sur., 1900, p. 89. P 104 Lower Limestone Group. 105 south to north through the different areas in which the district has been divided for descriptive purposes. c. 7. ¢, Lower LIMESTONE Group. COBBINSHAW AND ADDIEWELL AREA (Sheet 31 in part). The Cobbinshaw-Hurlet Limestone enters Sheet 32 at the south end of Cobbinshaw Reservoir. Immediately below the limestone lies the Cobbinshaw Coal,* which has been wrought over this portion of the field from Viewfield coal pit, situated just outside the limits -of the Sheet. In this working the limestone formed the roof, and the section was as follows :— Ft. In. Blaes.. Limestone .. Es wits sé ee a ae 20 Black blaes .. S04 ax ns sci ae .. 2 6 Coan ne i sk ag a . 8 9 Pavement—blaes A little to the south-west of pebindiaw Station both limestone and coal are wrought by means of a mine, and both are thicker than at Viewfield, as shown in the subjoined section :— Ft. In Roof—shale .. i “oe dv os at jee OOF. Limestone as Se <3 i ae . 5 6 Blaes.. 3.0 Coan 5 4 0 Pavement—fireclay 0 9 13 10 At this mine the coal is first taken out, and on removing the props the overlying blaes and limestone fall down. At the base of the coal there are lines of brassy balls which consist of very fine casts -of Bellerophon in iron pyrites. The blaes is aluminous and contains a “brown stone,” composed partly of parrot coal, and partly of iron- stone. The limestone is a dark-grey encrinital bed, very fossiliferous and weathers with a brown crust. It is burnt in draw-kilns close to the mine mouth. The greater part of the coal, which is of inferior quality, is used for lime-burning and the surplus is sold as fuel. A little distance to the west of Cobbinshaw Station, the coal was reached by a pit 22 fms. deep, and to the north of this locality the Pearie Law fault brings up the underlying Oil-shale group. The effect of this fracture combined with the Murieston fault is to shift the out- crops of the limestone and coal to within half a mile of Baad’s Mill. A short distance above the mill, on the side of the Harwood Water, an old quarry with the remains of a kiln indicates that the limestone was quarried and burnt with its coal at this point. Lower down the stream a thin rough coal crops out 150 ft. below the limestone. From Baad’s Mill the limestone appears to pass by the east of Townhead (Sheet 31) to the Longhill Burn, where there are several ‘quarries now grassed over. On the north side of this stream the * As this limestone is taken as the bottom bed of the Carboniferous Limestone Series, the underlying coal ought strictly to be described with the Calciferous Sandstone series, but it has so often to be mentioned in connection with the limestone that it is best to describe the two together. 106 Carboniferous Limestone Series of Bathgate and Bo’ness District. outcrop is interrupted by several faults, but, from the west side of Addiewell Chemical Works to Addiewell Bridge, the position of the limestone is again indicated by a chain of abandoned quarries. On the south side of Addiewell Bridge the limestone and coal were wrought together opencast and afterwards by shallow pits, which gave the following section :— Ft. In. Limestone 4 0 Blaes .. 16 Coan 5 6 In the Breich Water just above the bridge the outcrop of the lime- stone is repeated by a small fault. Between Addiewell Bridge and Blackburn Hall, the limestone has not been wrought, but the under- lying coal has been opened out to the north of Cuthill and found to be four feet thick. Several limestones occur above the Cobbinshaw-Hurlet Limestone in the burn opposite the shooting lodge on Pates Hill; two of which are thin, weather with a calmy yellow crust, and are separated by 18 ft. of black shale with ironstone nodules. The lowest band is one foot thick and the upper, four to five feet, and, when fresh, each is a solid blue-black limestone. These limestones are estimated to lie about 450 ft. above the Cobbinshaw-Hurlet Limestone. A short dis- tance up this stream there are old limestone quarries all grassed over. On the south side of the large east and west fault that crosses Leven Seat (one-inch map 31), one of the last-mentioned limestones is exposed along the crest of an anticlinal fold, and is in two leaves. On the east and west sides of the plication two small streams show that about 190 ft. of black shale separate this limestone from two higher ones. In the middle of this shale lies a rough ironstone which has been wrought opencast. The two higher limestones appear on the east side of the arch, about a mile and a quarter from the south- west corner of Sheet 32. The best section of the Lower Limestone group is exposed in the Breich Water. Here the beds overlying the Cobbinshaw-Hurlet Limestone are shales and soft flaggy sandstones with two coal seams one of which has been wrought. About thirty feet above the highest of these seams a grassy hollow with limestone fragments marks the position of the first limestone above the Cobbinshaw-Hurlet. The interval between this old quarry and the intrusive sill shown on the map is occupied with bands of shale and faky sandstone. The section in the main stream ceases with the igneous intrusion but is continued in the Skolie Burn, at the mouth of which, and for some distance to the south, two bands of limestone, one foot and five feet thick respectively, and separated by nine feet of fossiliferous shale, all dipping to west, are wellexposed. These limestones are estimated to lie about 425 ft. above the Cobbinshaw-Hurlet, and are probably the northern extension of the bands at Pates Hill. They are succeeded by blue-black shales overlain by a dark limestone with a very fossil- iferous shale. Above the limestone comes a considerable thickness of blue-black shale with a nodular fireclay, on top of which is a dark limestone, 2 ft. 10 in. thick. It seems probable that all these lime- stones above the Cobbinshaw-Hurlet correspond to the Hosie Lime- stones of Fife. The estimated distance between the top of the Lower Limestone Group. 107 highest of these Skolie Burn limestones and the base of the Cobbin- shaw Limestone is about 520 ft. J. 8. G, W. BATHGATE AREA (Sheet 31). The next section to the north of the Breich Water (Sheet 31) is furnished by the Almond, and presents a sequence agreeing exactly with that occurring to the south. It affords no evidence of a transi- tion towards the abnormal development which characterises the group only one or two miles farther north, in the volcanic district of the Bathgate Hills. In the description of the Calciferous Sandstone series (p. 95), mention has already been made of an encrinital limestone, one foot thick, which is exposed in the Almond, 300 yds. above Hopefield Mills. The section above this limestone is incomplete, but there is room for several hundred feet of strata between it and the Cobbinshaw- Hurlet band, the latter being well exposed in the bed of the stream, where it is an encrinital limestone similar to that of the Breich Water, The underlying coal is not exposed in the burn, but the following section is taken from the Redhouse Colliery situated a'little to the north :— Ft. Limestone es <3 ie wise iN a ae 48 Parrot CoaL 3 os x 36 ns .. 8in, FREE COAL .. ee ee is ie ein 2 Gas Coat and ironstone balls ee ae oh .. 8in. Cement and ferruginous limestone .. . Bi ws 3 Shaly sandstone ng i a ee is -» 10 CoaL. i ee sie is oe . 4 WILD Gas Coan 2 Hard brown sandstone The section of the strata overlying this limestone in the stream is not continuous, but for some distance it shows black shales and faky sandstones: about 150 ft. above the limestone a thin impersistent encrinital bed has also been recognised resting upon some faky sand- stones interbedded between two thick black shales. Higher up the burn a massive sandstone is exposed, a little below which a coal was worked at the outcrop on the northern bank. This sandstone and coal have also been recognised in the Breich Water to the south, Almost directly above the sandstone comes a bed of encrinital lime- stone, about eight feet thick, which closely resembles the Cobbinshaw- Hurlet, but probably lies about 300 ft. above it. It has been wrought on both sides of the stream, and is underlain by a thin coal.* The exposure of this limestone in the Almond serves to supplement the Breich section, for in the latter the position is only indicated by an old quarry now completely grassed over. At the present time there is no exposure in the stream to the west of this limestone, but Sir A. Geikie mapped another thin band of en- crinital limestone, 14 ft. thick, which was exposed just to the east of the “leckstone ” quarry, and underlain by a coal eight or nine inches thick, Moreover, a few bores put down in this locality indicate the presence of at least another limestone, 8 ft. thick, which probably crosses the *“The Geology of the Neighbourhood of Edinburgh,” Mem. Geol. Sur., 1861, p. 55. 108 Carboniferous Limestone Series of Bathgate and Bo'ness District. stream a little west of Blackburn Bridge. A blackband ironstone about a foot thick is recorded in the same bores about 27 fms. beneath this limestone. There can be no question that these upper beds belong to the group, already described, as occurring in the Skolie Burn, the small tributary that joins the Breich Water near Addie- well. No contemporaneous volcanic rocks are known in the Lower Limestone group of the Almond section. The “leckstone” or picrite of Blackburn was formerly described as a lava flow,* but it must no doubt be classed with the picrite of Breich Water, which is now held to be an intrusion (p. 281). Between the Almond section and the Bathgate Hills the country is covered with deep boulder clay, wide stretches of peat, and other superficial deposits. In the first sections in the hill country, some two miles north of the Almond, the beds of the Lower Limestone group are so different from those just described that any correlation of individual bands in the two areas can only be advanced with considerable hesitation. Before attempting this correlation it will be advantageous to refer to the northern succession. In the West Kirkton Quarry, a mile to the east of Bathgate, a marine limestone is exposed, the upper portion of which is interleaved with beds of volcanic ash.t The following section was recorded at the time of the original Survey : [— Dark basalt (diabase). Limestone, with thin layers of green tuff. Limestone in thick beds ; containing encrinites, Productus, etc. Thin shale. Green tuff. Limestone, ashy, and especially fossiliferous at the top, more shaly at bottom. . Dirty green, fine-grained, well-bedded tuff, containing a thin bed or vein of basalt 3 in. thick, and resting on a basalt sheet. The upper ashy portion is about 15 ft. thick, and the limestone proper, fully 10 ft. Large chert nodules occur sparingly in the limestone. The physical conditions indicated by these deposits contrast strongly with those shown by the underlying beds of the East Kirkton Quarry, to be described later in connection with the volcanic group. In the west quarry “ we see still the same evidences of the ejection of volcanic dust after the eruption of the basalt, but in place of the remains of land plants, we have now abundant traces of marine life, producte, spwrifers, crinoids and corals; showing that the area had undergone a submergence below the sea.. The siliceous matter occurs but sparingly, although there is still abundant evidence of voleanic action, the shells and zoophytes appearing not infrequently.to have been destroyed by being enveloped in a thickening deposit of ash.” § The West Kirkton Limestone has been correlated with the * Explanation of Sheet 31, Mem. Geol. Sur., 1879, p. 24, and Sir A. Geikie’s “ Ancient Volcanoes of Great Britain,” 1897, vol. i. p. 419. t Probably the first good account of the section was that given by Hay Cunningham in his “‘ Geology of the Lothians,” 1838, p. 106, plate xii. fig. 3. } Explanation of Sheet 31, Mem. Geol. Sur., 1879, p. 19. The brackets in which diabase is inserted appear in the original. a “The Geology of the Neighbourhood of Edinburgh,” Mem. Geol. Sur., 1861, p. 51. Lower Limestone Group. 109 Tartraven Limestone, which occurs farther to the north, and this correlation seems well founded, being based upon the similar strati- graphical position of the two with reference to the overlying Petershill Limestone. The latter is an excellent horizon, and has furnished invaluable assistance in unravelling the structure of the volcanic range, for it has been opened up in a series of quarries which extend without much interruption for about five miles. At West Kirkton the thickness of strata, including lavas, between the two limestones may be estimated at somewhat over 300 ft. The lower two-thirds of this sequence is composed mainly of basalt, and the upper third, of sedimentary strata, the bottom 60 ft. consisting chiefly of sandstone, as shown in a bore, the journal of which has been communicated by the Bathgate Borough Council. To the north of the road that crosses the Petershill Quarries additional lava streams occur, and for some distance occupy the position of the sedimentary strata just referred to, but, at the Knock, sandstones reappear underneath the Petershill Limestone and separated from it merely by a thin bed of ash. The Petershill Limestone, being a thick bed, long worked and richly fossiliferous, has been known since the earliest days of geology, and is still a favourite collecting ground. The full thickness is not ex- posed in any of the Petershill Quarries but it was formerly * estimated at about 70 or 80 ft. Its lowest portion is well seen in the Bathgate Reservoir just north of the Petershill road, and is remarkable for the abundance and good preservation of its fossils. Bands of different paleontological character may be recognised, some consisting almost entirely of Lithostrotion, others of large cup corals, others again of Productus giganteus, while more shaly layers are distinguished by the abundance of Pterinopecten and other mud-frequenting forms. The main mass of the limestone is less fossiliferous, but towards the top a zone rich in Productus giganteus and another with abundant encrinites may frequently be noted, A characteristic of one of the upper zones is the frequent occurrence of chert in large irregularly shaped masses, within which the more or less silicified remains of encrinites and other originally calcareous forms can be readily recognised. Dr. Crampton suggests that the silica may have been derived from sponge skeletons, which form an important though rather inconspicuous element in the composition of the limestone. In the Gallabraes Quarry, a little to the north, a persistent bed of white sandstone rests directly on the limestone and is surmounted in turn by a thick black shale. Farther north, before reaching the Knock, and just south of where an east and west dolerite dyke crosses the line of quarries, the sandstone extends into a curious cavity in the limestone, and, till examined closely, presents the appearance of a lenticular sill of “ white trap.” The same thin bed of sandstone may be followed through the Silvermine Quarries to the north and reappears at Hillhouse. In the district of West Kirkton and Petershill it is impossible to draw a line between the Lower Limestone group and the Bo’ness and Bathgate Coal group. A great mass of basaltic lavas occurs about this position, and the few intercalations of sedimentary material exposed are devoid of special interest, * Op. cit. p, 54. 110 Carboniferous Limestone Series of Bathgate and Bo'ness District. Limestones that come above the Petershill bed, which also belong to the Lower Limestone group, are known, however, to the north, at Wairdlaw and Carriden,* and two thin limestones apparently on a similar horizon have recently been proved in a bore situated a mile to the south of Bathgate, which gave the following section: + — Fms. Ft. In. Matin Coan ie ue 4 8 ee co, OO -& —t Strata with some igneous rocks .. 2 .. 87 O 7 _ Limy blaes with shells es 0 oll LIMESTONE ee be 0 2 6 Blaes.. 0 oO il Coan 0 0 2 Sandstone Oo 1 6 Faky blaes .. 0 0 6 Sandstone 2 3 11 Faky sandstone 1 1 2 Blaes .. te 0 0 4 Fakes and blaes 1 4 10 Blaes and ribs 4 2 6 Blaes and balls 1 0 2g Ironstone ball 0 oO 1 Blaes and ribs 0 5 =O Blaes with shells o 1 8 LimEsTonE F Oo 2 ii Blaes .. te is oa 0 1 11 Blaes and ironstone ribs .. % 0 2 8 Sandstone Se 0 O 5 The Main Coal referred to in the above section is a well-known member of the Bathgate Coal group, and has been followed to the north, where it overlies the mass of voleanic rocks with which the Petershill Limestone is interbedded. The two thin limestones of the bore can scarcely be regarded as representatives of the latter lime- stone, and it seems extremely probable that they overlie it. The cores on examination showed the limestones to be dark and shaly, rich in marine lamellibranchs and resembling those of Skolie Burn. It is clear, in fact, that the limestones of the bore belong to the Skolie Burn group, recognisable to the north again at Carriden, and upon this basis we may again attempt the difficult task of correlating the Cobbinshaw-Hurlet band with one or other of the Bathgate Limestones. The view originally expressed by Sir A. Geikie{ was that the West Kirkton Limestone probably represents the Cobbin- shaw-Hurlet Limestone, and that the Petershill Limestone is the continuation of the 8-ft. limestone exposed in the Almond section about 300 ft. above the latter. In later publications he abandoned this view and correlated the Petershill with the Hurlet Limestone. Mr. Cadell § has, however, returned to the earlier interpretation, which, for the following reasons, has been adopted in this memoir. It is assumed that the limestones in the bore a mile south of Bath- gate are equivalent to the upper or Skolie Burn group of limestones of the Breich and Almond. Beneath this upper group, two specially * See pp. 111 and 113 of this memoir. : + Communicated by Messrs. Gavin Paul & Co. The thicknesses given have been corrected for a dip of 25°. +“ The Geology of the Neighbourhood of Edinburgh,” Mem. Geol. Sur., 1861, pp. 53 and 55. ; . ; § ‘Carboniferous Limestone Coal-Fields of West Lothian,” Trans. Inst. Min. Engrs., 1901, plate x. Lower Limestone Group. 111 important beds of marine limestone occur in the Bathgate Hills and in the Blackburn-Cobbinshaw District, namely, the Petershill and West Kirkton Limestones in the former, and an unnamed limestone, together with the Cobbinshaw-Hurlet, in the latter. In both areas the interval between the two limestones mentioned is about 300 ft., and it seems reasonable to correlate the one pair with the other. This leads back to Sir A. Geikie’s original view that the West Kirkton band is the Hurlet Limestone of Cobbinshaw, and that the Petershill bed is the unnamed limestone of the Almond section.* E. B, B. TARTRAVEN TO HILLHOUSE. Northward from West Kirkton, the lowest limestone is exposed in a very poor section at Tartraven. Nothing is seen of the coal said to exist below, and the blaes above is quickly succeeded by a basalt. Beyond Tartraven the crop of the limestone is obscured by drift until the quarry at Whitebaulks is reached. The limestone exposed in the quarries at the Silvermine (Sheet 31) is obviously a continuation of the Petershill Limestone, and is overlain by a similar series of sediments. Immediately above the limestone comes a thin bed of sandstone succeeded by a thick series of blaes, which pass up through faky beds into sandstone. In the North Mine Quarry the beds above the limestone are different. Resting on the limestone is a bed of fireclay with a layer of flattened casts of Stigmaria on its upper surface. Next follows a grey mica- ceous sandstone overlain by a blue and green ash and some blaes, the latter being in turn covered by basalt. The limestone probably passes through the swampy hollow running northwards from the quarries, but it is not again seen at the surface before the Hillhouse Quarries are reached. At Wairdlaw, on the summit ridge of the Bathgate Hills, we meet with a local lenticular limestone higher than the Petershill Limestone. Whilst its horizon is evidently that of the Carriden and Skolie Burn Limestones, its peculiar character and position amidst basaltic lavas prevent an exact correlation being made. In the abundance of Lithostrotion irregulare, the close-set stems of which constitute entire layers of the rock, it differs from every other lime- stone of the district, except the Lower Kinning Point Limestone of the Charlestown district, which is also characterised by bands of Lithostro- tion. The following section is seen in the quarry at Wairdlaw :— Ft. In. Platy basalt is Ms Blue blaes, dark and compact above,with Calamztes, Productus and scales of Paleoniscus oo es ae Limestone with some pyrites Dark blaes . ‘se as Impure shaly limestone. . ee a Rib of hard compact shale with crinoids ns ae Limestone with shaly partings and band of Lithostrotion Black blaes ee aa sy ig 5 sy Limestone with Lithostrotton Amygdaloidal basalt WORKER OR AWOUWUDOAQA H. B. M. * For further evidence upon this question see the description of the Lower Lime- stone group in the south-west of Fifeshire (p.116 of this memoir), 112 Carboniferous Limestone Series of Bathgate and Bo'ness District. HILLHOUSE TO LINLITHGOW, The lowest limestone of the series is that formerly worked -at Whitebaulks ; it is about ten or twelve feet thick, of a compact bluish- grey texture with abundant fragments of small encrinites, and rests on a seam of coal from eight to ten inches thick. Farther north, it is. seen.dipping steeply to the west on the top and south side of Carsie. Hill,* where it is a rusty crinoidal bed, 13 ft. thick, the colour of which is due to weathering of chalybite; when tested with hydro- chloric acid it gives a yellowish liquid showing the presence of iron in fair quantity ; the residue from solution is largely carbonaceous with'a little heavier matter. Some of this carbonaceous residue is seen under the microscope to consist of minute spheres abput geso in. in diameter, which may be spores of some Carboniferous eryptogam. The structure of the ground in which. this limestone occurs is difficult to understand, as only 150 yds, to the east a bed of limestone is again seen on the north side of the ridge dipping gently to the east and overlain by cherts, which are also seen on this slope about 100 yds. farther west. A small mound isolated by the alluvium, 200 yds. north of this ridge, shows pieces of shale and sandstone and small fragments of chert, but whether these are close to.their source it is impossible to say; in fact, north of Carsie Hill we have no evidence on this horizon. At Whitebaulks the limestone is overlain by a black shale which is seen also above the bed at Carsie Hill. In a quarry on the south side of the road at Cauldhame a bed of sandstone, over 50 ft. thick, is exposed without reaching the base, and above it, some sandy shales; this bed may be the upper part of that once worked at Porterside and seen on the ridge east of Cauld- hame, where it occupies most of the ground between the limestone and the neck. A bed of ash exposed on the road at Whitebaulks marks the base of the largest series of eruptive rocks in the area. It continues northward as far as Hillhouse, a little beyond which it ceases to be distinctly traceable. The Hillhouse Limestone is exposed west of the farms of Hill- house and Whitebaulks in a long series of quarries, trending 5.8. W. for nearly half a mile, in which it has been extensively worked, but is now no longer used. The beds exposed vary in detail from point to point, but the section immediately south of the road a quarter of a mile north-west of Whitebaulks may be given as a type, and is as follows :— Columnar basalt, intrusive Sandy shale .. 0 6 Coal ioe ae 0 6 Sandstone .., ins ei oe uf + .. 38 6 Sandy shale .. es “a ee ag 3 . 5 0 Dark shale . . 19 Sandstone 1.0 Ash .. 1 0 “- *€Carsie Hill is not marked on Sheet 32; it lies 380 yds. east of Cauldhame. Lower Limestone Group. 113 Ft. In. Sandstone 2 0 Sandy shale.. 5 0 Dark shale .. 1 0 Light clay 1 0 LIMESTONE The whole thickness of the limestone is not seen, but a section formerly exposed at the north end of the quarries is said to have shown 30 ft. of limestone and some shale below. The journal of a bore, put down a little way north of the locality where the limestone is last seen south of Hiltly, records 6 ft. of shale resting on 4 ft. of limestone. This shale may be that below the limestone, just referred to; so that the total thickness of the limestone, including the shale associated with it, may be 40 ft. The limestone itself varies from band to band, being in parts crinoidal, while in others it is richly coralline, containing both solitary and colonial coral forms with occasional Productus and other brachiopods. It hardly seems possible that such a thick bed of limestone can exist farther north, for, in spite of the numerous exposures around Hiltly, which reveal,a complex assemblage of basalts and fragmental rocks, there is no evidence of any limestone. A boring was made 350 yds. W.S.W. of the Manse, the journal of which has been lost, but Mr. Wylie, the borer, states that it was 130 fms. deep and pierced a thick bed of limestone near the bottom. During the making of the foundations for the Hospital west of Linlithgow Poorhouse, a band of crinoidal limestone, about four feet thick, was noticed by Mr. Cadell, which seems to be the limestone passed through in the well at the St. Magdalene Distillery at a depth of 66 ft., as a dip of 10° was found in the strata still exposed near the Hospital. Should this dip continue, a thick limestone lower down the well should crop out about a third of a mile east of Clarendon House, where its hypothetical position is shown on the map. This thick limestone is 220 ft. below the upper one, and it may occupy the position of the Hillhouse bed. G.W.G. LINLITHGOW TO CARRIDEN. The total thickness of the Lower Limestone group in this area is perhaps 500 or 600 ft., but our knowledge of the lower strata is exceed- ingly slight. Three limestones belonging to the group are seen on or near the coast near Carriden: others in lower positions are recorded in bore journals but never exposed in this district. The highest of those visible on the shore is taken as the top bed of the Lower Limestone group, and has long been known as the Carriden Limestone. In this memoir it will be referred to as the Carriden Upper Limestone, to distinguish it from the other two, which will be termed the Carriden Middle and Lower Limestones. Part of the Carriden Lower Limestone is seen on the shore a few feet below the Carriden Volcanic Ash, about 300 yds. E.N.E. of Carriden House: this horizon is only a little above the lowest beds of the Lower Limestone group which are visible in this area. The basal band, a hard calcareous sandstone with markings of Cauda-galli, is overlain by six or seven inches of shaly crinoidal limestone, above 8 114 Carboniferous Limestone Series of Bathgate and Bo'ness District. which comes an obscure space in which additional calcareous bands probably occur; but the whole bed cannot exceed three or four feet in thickness, as it must pass beneath the position of a thin coal seam that was formerly exposed on the shore not far above the calcareous sandstone. In a boring near No. 9 Pit, Grange, the section of the limestone and of the two caleareous bands below is recorded as follows :-— Ft. In LIMESTONE ae a ae ee ee . 8 4 Black blaes .. ete Se oe en oe IG LIMESTONE a ts ae 3% es we 0 2 Dark fireclay es “8 a a nated Limy fakes .. wi 2 5 In a boring 100 yds. east of Canviden ‘Churoh—ueually termed the Cuffabouts boring—the sequence recorded is somewhat similar, namely :— Ft. In. LIMESTONE Be se be i sis Bs oe DO Black blaes .. oe ee a Bs es - 2 3 LIMESTONE on sm oe ME A ae . 0 4 From the above and other borings it is clear that at a depth of about 200 ft. below the Smithy Coal there is an horizon, sometimes more than 60 ft. thick, which contains several thin bands of lime- stone separated by various sediments. It is probable that the Carriden Lower Limestone forms the top of the calcareous horizon, and that other limestones, not exposed in this area, occur a little distance below it. The only beds seen at Carriden below this limestone are sandstones with a parting containing a coal five or six inches thick. The section somewhat resembles that in the railway cutting west of Charlestown, where a limestone crops out between a bed of ash and a coal with a fireclay seat. This limestone in the cutting is supposed by Mr. Maufe to be about 160 ft. above the thick Charlestown Limestone, and it is therefore doubtful whether any of the bores at Bridgeness went deep enough to reach the position of the latter, though the bore at Springfield, the journal of the lower part of which has been lost, may have done so. The thin coal under the Carriden Lower Limestone on the shore is represented by a thicker seam in the Cuffabouts bore, where it is composed of an upper part of strong coal, 18 in. thick, and an under part of strong coal, 7 in. thick, with a one-inch parting of fireclay between the two. In the bore near No, 9 Pit, Grange, on the other hand, this coal appears to be represented by 25 in. of coaly blaes merely. Carriden Pit bore No. 1, on the foreshore about 516 yds. N.E. by E. of Carriden Church, is supposed to have crossed, at a depth of 118 ft. an important fault—perhaps the east and west fault with considerable downthrow to the north, which passes a little south of Bridgeness. After crossing the supposed fault, the bore pierced a two-foot coal, at a depth of 260 ft., and it seems probable that it is in the position of the coal just alluded to in the Cuffabouts bore. About 59 ft. below this seam the bore entered calcareous beds and limestones which were proved to be more than 11 ft. thick without reaching the base, Lower Limestone Group. 115 At Carriden, the ash that comes above the little coal overlying the Carriden Lower Limestone is probably 40 or 50 ft. thick, and in Carriden Glen it is overlain directly by the Carriden Middle Limestone, which also seems to contain some ashy material. This limestone is crinoidal in the centre but only about 18 in. thick, and it is not clear that it is represented in the adjacent bores. Above the Carriden Middle Limestone in the glen come 12 or 14 feet of shale, followed by about 40 ft. of flaggy sandstone with thin shaly partings, succeeded in turn by the Carriden Upper Limestone, which in this locality seems only a foot thick. A better exposure of this upper band is to be found in the old sandstone quarry a quarter of a mile east of Carriden Church, where it is afoot and a half thick, and rests on two feet of sandy clay. It weathers with a yellow colour and contains some crinoid joints, but is not rich in fossils. It seems to increase in thickness in a west or north-west direction, for in the Cuffabouts bore it is stated to be 2 ff. 7 in. thick, including a three-inch shale band, and in the bore near No. 9 Pit, Grange, it is 4 ft. 2 in, including a three-inch parting. In the last bore the limestone is 90 ft. below the Smithy Coal. Inland south of Carriden the only satisfactory information obtained concerning this group is provided by a few bores. There is no evidence that the Carriden Upper Limestone exists in this land- ward area, and it seems probable that both it and the sediments, which at Carriden come between it and the Carriden Middle Lime- stone, are often represented by igneous rocks. In the journal of the bore at Springfield the topmost rocks for 11 fms. are called fakes and fireclay, and perhaps they represent the volcanic ash of Carriden Glen. Below these comes an impure limestone, 2 ft. 4 in. thick, which perhaps represents the Carriden Middle Limestone, and at depths of 48 and 62 ft. farther down other impure limestones occur, the top one, 25 in. thick, and the bottom one, 5 ft.8in. The journal only extends 36 ft. below the bottom limestone, but it is reported that the bore went to a depth of 60 or 70 fms. and cut a five-foot seam of good limestone, as well as a thick sandstone over- lying a little coal. It seems not unlikely that the five-foot lime- stone reported may represent the thick Charlestown Limestone, which has been so much quarried at Charlestown on the north side of the Forth, and also the Hillhouse Limestone south-east of Linlithgow. Another bore, No. 1 Burghmuir, reached, at a depth of 308 ft. beneath the rock surface, a four-foot limestone, below which came dark blaes 3 ft. 8 in. thick, and then nine inches of lime-fakes. It is probable that this bore started in beds below the lowest lime- stone of the Springfield bore, and that the limestone pierced by the Burghmuir Bore corresponds to the bed of limestone on the shore near Charlestown railway station—the bed taken as the base of the Carboniferous Limestone series in that locality—though the interval between it and the next important higher limestone is greater than that between the two limestones referred to at Charlestown. Before reaching the limestone the bore pierced a sandstone, 78 ft. thick, and an underlying thick shale with clay band ironstones: this thick sandstone may represent the sandstone in the cliffs at Charles- town above the limestone near the station. A little above this thick 116 Carboniferous Limestone Series of Bathgate and Bo'ness District. sandstone, the bore records a bed of lime and iron, 114 in. thick, which perhaps represents one of the thin limestones seen at Charles- town between the thick sandstone and the Charlestown Limestone. We have, therefore, in this locality drawn the base of the Carbon- iferous Limestone series at the base of the supposed outcrop of the Burghmuir Limestone. OG. 1. G CHARLESTOWN AND LIMEKILNS ( FIFE). The acceptance of the Cobbinshaw Limestone as the basal lime- stone of the Carboniferous Limestone series necessitated an altera- tion in the lower limit of the series in the neighbourhood of Charlestown, where the thick Charlestown Limestone has hitherto been regarded as the base. The Charlestown Limestone is distinguished from the other lime- stones of the neighbourhood by its greater thickness (20 to 40 ft.), the presence of cherts, and the abundance of Productus giganteus. In precisely the same points it resembles the Petershill and Silver- mine Limestone of the Bathgate Hills, and there can be little doubt that they belong to the same horizon. In the large quarries the Charlestown Limestone is succeeded by a thick mass of blaes, which pass up through fakes into a thick sandstone, a succession which is similar to that seen in the Silvermine Quarry, about two miles N.N.E. of Bathgate (Sheet 31). Beneath the limestone in descending sequence is a bed of shale, a foot or two thick, encrinital limestone two feet thick, another bed of shale, and then a thin bright coal, which some- times passes laterally into coaly blaes. The limestone, which probably lies on the horizon of the Hurlet Limestone of Cobbinshaw, is exposed on the shore below Charlestown railway station in a small faulted down patch with quaquaversal dip. It is a dark encrinital limestone, which lies about 150 ft. beneath the Charlestown Limestone. By excavation into the beach the following section was proved :— Ft. In. Blaes ah ie Ags a ie Dark encrinital limestone re cs “ Bh .. 4 0 Dark blaes with fossils .. 58 iis a es .. 4 6 Coal, with pene band i ba oh 0 10 Fireclay i is i .. morethan 3 0 This limestone is seen again on the shore opposite the school at Limekilns, whence its outcrop runs obliquely up the face of the cliff behind the village and is then lost beneath the covering of drift. It is exposed, however, on the east side of the Rosyth anticline at the mouth of the old fireclay mine at Sunnybank, north of Tnverkeithing, and again at high-water mark a quarter of a mile west of Rosyth Farm. At the latter place the limestone seems to lie in a shallow basin, and is certainly faulted down against the Calciferous Sandstone series both to the south and to the west. From the black shales beneath the limestone Mr. Tait collected a suite of fossils very similar to those found in the shale beneath the limestone at Charlestown railway station. This dark encrinital limestone is the lowest thoroughly marine limestone in the district, and as it resembles in character and Lower Limestone Group—Bo’ness and Bathgate Coal Group. 117 position the Hurlet Limestone of Cobbinshaw, it is taken as the base of the Carboniferous Limestone series in this district. The limestones, which occur at horizons above the Charlestown Limestone, may be briefly described. The first of these is exposed in a little syncline in a railway cutting three-quarters of a mile west of Charlestown station, and lies about 180 ft. above the Charlestown Limestone. The following section is shown’ in the cutting :— Coarse volcanic tuff sh te oh aie ea Dark limestone .. es ee 34 on .. 2ft. to Sandstone. . ie ae sie Shale Coal a be Fireclay and blaes Dep rowwe cOoSOMOoF Excepting a small isolated crop of limestone near the tuffs in the middle of Ironmill Bay, the next limestones met with are the three bands at Kinniny Point, the lowest of which is about two feet thick, with shale and a thin seam of coal beneath it. It is easily distinguished by its layers of Lithostrotion irregulare. Above it comes blaes containing ironstone nodules, which were wrought formerly along the outcrop, and then a calcareous sandstone, which contains occasional patches of tuff and exhibits a curious curved bedding. The Middle Kinniny Limestone, from 6 to 8 ft. thick and about 25 ft. above the lower band, is charged with en- crinites, and crops out in the bed of the stream north of Balbougie (14 mile N.N.E. of Inverkeithing). The Upper Kinniny Limestone is very hard, varies from one to two feet in thickness, and lies immediately on a bed of gannister about 80 ft. above the middle band. Inland it has been recognised in the burn below Balbougie. It is characterised by numbers of Bellerophon, and is probably the same as the top Hosie Limestone described by Dr. Crampton in the Campsie district.* H. B. M. Bo’NESS AND BATHGATE CoaL GROUP. Throughout the greater part of the area between Bo'ness and the southern margin of the one-inch map 31 near Leven Seat, a portion of the Bo'ness and Bathgate Coal group is represented by volcanic rocks, and these increase so much in thickness towards Linlithgow that for a time in this neighbourhood no coal seams - appear to have been formed. Thus the outcrop of the coal-bearing strata may be. divided into two areas—a northern area, extending from Bo’ness to near Linlithgow, and a southern area, extending from the southern edge of the map to the neighbourhood of Kipps; but neither the southern edge of the northern area nor the northern edge of the southern area are well defined. The intermediate area, which extends from Linlithgow southward to the neighbourhood of Kipps, is only about two miles in length along the strike, but it is a remarkable fact that up to the present time it has been found impossible to correlate any of the seams in the northern area with those in the southern. ~ * «Summary of Progress,’ Mem. Geol. Sur. for 1904, p. 100. 118 Carboniferous Limestone Series of Bathgate and Bo'ness District. The development of the group to be described has been dealt with in various valuable papers by Mr. Cadell, to whom special thanks are due for much kind assistance rendered during the course of the revision. C.T.C. WOODMUIR AND FOULSHIELS AREA SOUTH OF BREICH WATER (Sheet 31). The coal crops shown in one-inch map 31 on the south side of the Leven Seat fault form the northern prolongation of the Wilsontown field, of which the following is the general section :— Ft. In Witsontown Marin Coan oe sit ae i . 4 6 Strata ae os na oe ao i .. 90 0 Magers Banps * or Hoge Fence [Ronstone 4 ss 1 4 Strata a8 24 ate ae che as .. 66 0 WILSoNTOWN Gas CoaL we ste xe Qin.to 1 8 Strata es as 7 ae .. 84 4 These all dip to west and are repeated to the east by the anticlinal fold on the south side of Hendreys Course. On the eastern side the coals and ironstones have been proved by bores to occupy a shallow synclinal fold,.and the Wilsontown Gas Coal is estimated to lie about 400 ft. above the Cobbinshaw Hurlet Limestone. The Leven Seat fault with a downthrow to the north causes this fold to occupy a broader area on its northern side eastward of Hendreys Course, but the fold dies out to north, and the crop of the Main Coal forms the segment of a circle extending from west to east. In the hollow between the western side of this segment and Hendreys Course the Main Coal is reported to have been opened out, and from numerous bores it appears that it occupies another smaller shallow basin. Three hundred yards to the south of the Cairn, a shallow pit proved the gas coal to be very coarse. Between this smaller basin and the Woodmuir Coal-field a flat anticlinal arch must intervene. The structure of the Woodmuir portion of the coal-field is very simple. From the Leven Seat fault to Longford Farm the general dip is W.N.W., but on the south side of the Caledonian Railway it changes to west, while the coal crops strike N. and 8. and are brought nearer together in consequence of the increased dip, of 15° or 20° The field is intersected by several cross faults, the more important of which will be shortly mentioned. On the south- east side of the Lanark road the outcrop of the Main Coal has been proved by crop pits, from the western side of Hendreys Course to the Bank Head dislocation, which strikes nearly east and west, crossing Skolie Burn about 630 yds. south of Blinkbonny and passing westwards close to Bank Head. The southern portion of the Woodmuir field was wrought some years ago by means of a shaft 40 fms. deep, and the workings proved several N.W. and S.E. faults. The colliery is now dismantled. On the south side of the Bank Head fault, in the Skolie Burn, an “ingoing eye” marks the position of the Wilsontown Main Coal, and a little distance to the east a pit reached the Wilsontown Gas Coal at 8 fms. *The term “Maggie” is applied to ironstones of inferior quality. Bo'ness and Bathgate Coal Group. 119 The Bank Head fault has a downthrow of 27 fms. to north, and shifts the outcrops of the Wilsontown Main and Gas Coals on the north side some distance towards the east. Farther north the point where the crop of the Main Coal crosses the Skolie Burn is again fixed by an “ingoing eye,” and the overlying strata are well exposed in the stream. This portion of the field was wrought as far as the Woodmuir east and west fault, by several shafts, the deepest reach- ing 52 fms. Ooking ovens were built, and the Woodmuir Smithy Coal produced a fair coke, but all the works are now dismantled. On the south side of the Woodmuir fault the average dip of the coal seams is 8° to 10° to W.N.W., but on the north side the structure is somewhat different, This fault has a downthrow of at least 36 fms. to north, and shifts the outcrop of the Main Coal nearly to Whole Stock, where the seam plunges down at an angle of 15° to a vertical depth of about 200 ft., and then changes to 3° and continues so for over half a mile in the direction of the present Woodmuir Pit. This field is at present wrought by the United Collieries Co., by shafts sunk a little to the south-west of Longford peat moss. A bore not far from the colliery gives the following section :— te NRE TE WRONNONEWNTHE AE ROCNARNOKRON Be Ke Pe DWOW;AEHTOOUOTMEP RK SE POWRWOUnNnNaAoWwNKWhooOote LimzstonE, Index Strata Coat No. 1 Strata Coat No. 2 Strata Coat No. 3 Strata si : Coat No. 4, “China » Strata ie Coat No. 5 Strata Coat No. 6 Strata Coat No. 7 Strata Coat No. 8 Strata Ms es Coat, “ Woodmuir Smithy ” Strata A ae Coat No.10 .. Strata ait 3% 4 i a eh Coat, “Lady Morton » as is ex . 2 ft. to Strata ee ss =a es = Coat No. 12 .. Strata . Coat No. 138 .. Strata is Coat No. 14, “Craw a Strata 7 Coat, Wilsontown Main bo e Poe a No -_-§ | = a bo The China, Smithy, and Lady Morton are the seams wrought at the Woodmuir Pit, the last at 51 fms. from the surface. The shaft has been carried down to the Wilsontown Main. From the above section it will be seen that there is a large number of thin coals between the workable seams. One of these, No. 10, in the coalfield not far to the north, attains a thickness of 2 ft. 3 in. 120 Carboniferous Limestone Series of Bathgate and Bo'ness District. and is known as the Splint. Asa general rule all the workable coals in- crease in thickness towards the north, as the following table shows :— Woodinuir Loganlea Foulshiels Colliery. Colliery. Colliery. Fins, Ft. In.| Fms. Ft. In. Fms. Ft. In. Carina Coau.. 2ft.to 0 2 6 03 3 02 9 Strata.. .. |9}fms.tol4 0 0 14 0 0 12 0 0 Woopmuirn SMITHY Coan lft.llin.to0 2 2 03 7 0 2 6 Strata ia 4 0 0 5 0 0 6 3 0 Lapy Morron or JEWEL CoaL 2ft.to O 210 0 3 :°0 0 310 Strata .. |10fms.to14 0 0 11 3 0 |9fms.tol2 0 0 WILSOoNTOWN or MAIN Coan .. “a 0 40 0 5 0 107 In Woodmuir Colliery the Wilsontown Main Coal frequently splits up into two leaves with a parting of shale which varies from 4 to 10 ft. No. 3 Coal in this field is probably the representative of the Balbardie Parrot Seam. At Loganlea and Foulshiels Collieries all the four seams are wrought, and the following comparative table shows the variations in thickness :— LogantEa. Ft. In. Roof, sandstone. CoaL .. a . 20 CuiIna Coan Dirt 2ft.9in. to O 6 | Coan ‘ . 0 9 3.3 Roof, sandstone. Blaes 1 2 Woopmuir |CoaL . 0 6 SmitHy Coan Ribs .. 0 2 . Coan 1 9 3.47 Pavement, fireclay. LapyMorton (Coat, “Craw” 0 10 or Roof, fireclay 9 0 JewEt Coat (Coat .. i 3.0 12 10 Coat, “Craw” Gin. to 0 2 Roof, sandstone 2 6 Coa 0 10 WILSONTOWN Dirt .. 0 10 Main Coat CoaL 2 0 Dirt .. 0 7 Coat 09 7 8 FouULsHIELS. Ft. In, Roof, fakes. Coa 2 6 Roof, sandstone. Blaes .. Coan Stone... CoaL wpooo w orRek & bo © woe Pavement, fireclay. Coat, “ Craw” Roof, blaes Coan. Dirt . Coan » Parrot ” 3 ft, 10 in. [LrerooorRe FOR ODD Oo @ toe Coat, “ Craw” Roof, firecla; Coat... Fireclay Coan Wild stone Coan 6 ft. 7 in, RPONrReS=Tp © DAAAHOO it on ~I Bo'ness and Bathgate Coal Group. 121 In the Lady Morton Seam at Foulshiels there is, near the base, a band of wild parrot which varies greatly in thickness and quality, The Wilsontown Gas Coal, which lies 25 fms. below the Main Coal, is too thin to be workable: its position has been proved in bores to the east of Longford and also at Foulshiels, where its average thick- ness is 9 in. This seam has been correlated with the Lesmahagow Gas Coal of Lanarkshire. At Foulshiels, the Balbardie Coal is not workable, but is known to be 18 to 24 ft. above the. China Coal.’ The quality of coal raised from these three collieries varies from second to third class. Between each of the seams the thickness of the separating strata also varies considerably. Between Longford and the outcrop of the Wilsontown Gas Coal to the east of Wood- muir a large number of bores have been put down, and these show a total thickness of 525 ft. of strata between the Index Limestone and the highest bed of the Lower Limestone group. J.8. GW. BATHGATE AREA (Sheet 31). Excepting the presence of the Bathgate lavas, the Bo’ness and Bathgate Coal group shows, in this area, a development very similar to that in the country between Leven Seat and Foulshiels already described. Here, also, the valuable coal seams occur only in the upper portion of the group, which, fortunately, in the Bathgate area is comparatively free from volcanic rocks. Exposures are few, and to the south of Bathgate the only surface indication of this division is the presence of a long line of coal-pits, which have of late years shown a tendency to advance ever farther towards the west, as the coals have been sought at continually increasing depths. But from Bathgate northwards the outcrop of the basalts underlying the workable coal seams can readily be followed, while to the west occasional exposures of the Index Limestone mark the limit in this direction of the surface extension of the group. For accurate knowledge concerning any but the volcanic portion of the series, we are almost everywhere in this district forced to rely upon mining information, which has been generously supplied. The coal seams run almost due north and south with a dip of about 25° towards the west. They are traversed by two east and west dolerite dykes, and are displaced by a series of east and west faults, whose downthrows are more often towards the south than the north. The most important of the faults — that against which the Bathgate Hills terminate on the south—is reckoned to have a downthrow of about 60 fms. to the south. Until recently, accurate knowledge regarding the sequence of the strata has been confined to the upper portion of this division, which contains the workable coal seams of the area. But in 1903* a bore was put down at Moss-side Colliery, east of Durhamtoun, which has proved the whole succession from the worked coals down to the Lower Limestone group. The volcanic rocks were here found in greatly diminished proportion compared with their development a short distance farther to the north, at * Since the publication of H. M. Cadell’s paper on ‘‘ The Carboniferous Limestone Coal-fields of West Lothian,” T'rans. Inst. Min. Engrs., 1901, vol. xxii. p. 372. 122 Carboniferous Limestone Series of Bo’ness and Bathgate District. Bathgate, so that it is now possible to be certain for the first time of the chief characteristics of the sedimentary sequence in this neighbourhood. The most noticeable feature is that the upper sub- division, which contains the four or five workable coal seams of the district, corresponds closely to the Possil group* of the Glasgow area, and is separated from the underlying comparatively barren measures by a Parrot Coal which is almost certainly the same as the Wilsontown and Lesmahagow Gas Coal of the south, and may also be taken as the representative of the Gas Coal of the west country. The Possil group in Linlithgowshire is, however, much poorer in blackband ironstones than in the typical area near Glasgow, and the underlying subdivision is in every way less productive than in the west. We shall first give the Moss-side section of this lower subdivision.t WILsontown Gas Coa. Ft. In. Whinstone (basalt) .. oa ot aa ae we DB Blaes, fakes, and fireclay Whinstone (basalt) Blue blaes x Coat with ribs Sandstone Blaes .. CoaL ioe Blaes, etc. Coan as ae a Fakes and sandstone . Coat (burned) .. as hes wa 4 i sn Sandstones with blaes. . ae we a he wa 24 Sandstone ss e% Pe at as aa .. 18 Blaes and balls a if ara ne aa bie 2 CoaL ans oi ae a ie ie ia je Blaes and sandstone ribs av ae wr ss .. 10 Sandstone aca is cl aa iva i oa EB Blaes oe Brown rib Fakes i Limestone band .. Blaes and faky rib Coan a Sandstone Blaes and ribs .. Coa aa ie bs Faky blaes and balls .. CoaL ave ae Sandstone Blaes Irony rib Blaes Sandstone Blaes .. 3 ie Sandstone and fakes . Blaes and balls ee Limy blaes with shells. Topmost Hostr LIMESTONE. ~ _ CONOR ROY ORF _ We OTD TH HEH DOWN WARAOMAWWNOMODHH e oy e a aT STE PATRON ® 290 5 * This correlation is based ser the work of R. G. Carruthers, whose results will be published in the memoir dealing with the Geology of the Glasgow district. ¢ Corrected for the dip at 25° so as to give the true thicknesses. Bo'ness and Bathgate Coal Group. 123 We may now pass on to consider the upper subdivision or Possil group, the development of which in the neighbourhood of Bathgate is illustrated by the following vertical section. The details down to the Main Coal* were obtained from a bore put down a mile to the west of the outcrop of the Index Limestone at Balbardie; while, between the Main and Gas Coals, the section is merely the upward continuation of that quoted above from the journal of the Moss-side Bore.t yy sh KH Inprex Limestone. Blaes Coat ’ Whinstone (basalt) Sandy fireclay .. igs BaLBARDIE Gas Coar— ‘WiLp Gas CoaL .. CANNEL CoaL IRONSTONE.. Fireclay .. FREE CoaL Fireclay ys Sandstone, fakes, and blaes .. Cuina or SHALY CoaL— Coan 5 Blaes band WILp CanngEL Coa CoaL es Sandstone, fakes, and blaes .. IRONSTONE ‘ oe Blaes .. Cement bed Coan hs Sandstone, fakes, and blaes .. CoaL 5 ie Sandy fakes, hard a8 Sandstone, fakes, and blaes .. Coau é a Fakes and sandstone ct Blaes .. Two-Foot CoaL ()— Coa Fireclay .. Coan Blaes Coan Fireclay oe Banister blaes, and fakes .. FIDDLE Coat (?) . 65 Fireclay Fakes and blaes. Coan : Blaes Sandstone JEWEL CoaL— CoaL as Blaes rib (Coax wo FOrFRFOOO BROOK — SOnow~arw RODWS —_ — — = aww ONPeK WARE OND =D SCOBOHRDOCOCRKAPRONK OTOH eH — CSCOrFOoFOCOR0CCOH bo — — COWwWow _ NOC OFMORFCOSCSO —_ poo aD Carry forward .. 172 * These have been already given by H. M. Cadell, ‘‘ The Carboniferous Limestone Coal-fields of West Lothian,” Trans. Inst. Min. Engrs., 1901, vol. xxii. p. 372. + As before, correction has been made for a dip of 25°. 124 Carboniferous Limestone Series of Bo’ness and Bathyate District. Ft. In. Brought forward .. 172 6 Blaes, fakes, and sandstone .. es i 3 st 10 Coan ana Fireclay Fakes and blaes | CoaL : : Fireclay Fakes Craw Coat, foul Rocky plies -Blaes Main Coat— Coal ats Fireclay .. 54 ws ae bes as Coal a4 ay ae A orn Blaes, coaly a es . Coal Fireclay rib Coal Cement rib Coal Sandstones with shales Blaes Ironstone Blaes Tronstone Blaes Ironstone Blaes White Rib Trony Band Blaes ye Grey sandstone Coa (with two ribs) Sandstone : Blaes (with iron ‘ribs towards base) . CoaL a ose fe 333 Faky fireclay 2 Sandstone Blaes .. Limy sandstone and balls Faky blaes Sandstone Coat with ribs Blaes Coarse sandstone Blaes and balJs Sandstone ‘ Fakes and blaes Coat (Blind Coal +) Grey sandstone and fakes Whinstone (basalt) Witsontown Gas CoaL— Parrot Coal mixed with Whinstone. . ~ ooorcoo°o NOTH HP OORCOD a arore — Maggie Bands ill WROOCWRHHNWHATADWONWOWONMNOAWAWAT ONDWORDDNNW De KH COOCCHOCOKOOCOM es _ _ OCARWNCKH HE KW hOOt oy WOO OF _ oO OCONONTCOWR TR AT a aN ~~ OW cS a oo Oo Combining these figures with those already given for the lower subdivision, we find that the Bo’ness and Bathgate Coal group in the Bathgate district has a total thickness of about 750 ft. + “ Blind Coal,” coal that burns without smoke or flame, having lost most of its volatile constituents. A variety of anthracite. Bo'ness and Bathgate Coal Group. 125 The whinstone beds in the foregoing sections consist of vesicular olivine basalts, and most of them are no doubt lava flows. Some of them, however, seem to behave as intrusions, and the Gas Coal, where it was encountered in the Moss-side Bore, was found to be pierced by ramifying basaltic veins, although, strange to say, the quality of the coal does not appear to have been materially impaired. We now proceed to summarise in comparative tables Mr. Cadell’s main conclusions relating to the variations in the develop- ient of the group which have been proved in the collieries at present working in the district.* Mosshall Boghead Balbardie near near near Foulshiels. | Durhamtoun.| Bathgate. Ft. In. Ft. In. Ft. In, INDEX LIMESTONE, Strata ie sad oe ee 24 «0 ao 60 44 0 BALBARDIE SEAM .. : 2 O 6 10 4 5 Strata ae aus 7 O 16 0 11 0 CHIna or SHALY Coa <3 es 2 10 Q 4 2 11 Strata .. sis os rs 86 (0 i} WoopMuir Coan ck a 2 6 98 0 105 =O Strata... a bh to JEWEL or LADY Morton Coa sie 5 5 3° % 3 2 Strata... ia oa tel ae 37 0 | 24 «0 Craw Coa... i a Be Ty & 5380 1 8 Strata .. .. .. ..| 9 0 J 9 0 Marin Coat.. a sa ssf 6 1] a. 12 5 11 247 «5 221 11 211 1 In none of the localities mentioned in these tables is there any . thick sandstone, but Mr. Cadellt gives the record of another bore, put down near Hilderston Farm, farther towards the north, in which a thick sandstone comes in and doubles the ordinary interval separating the Index Limestone and the Balbardie Seam. The portion of the journal which bears upon this point is as follows :— Ft. In. Index Limestone ‘6 os 2 “ si Gis Ar slals Blaes and balls : — ee ie xe Light setae ba and ironstone balls .. aa 8 ve 99: 49 Fakes .. a oe ms « 2 0 Sandstone nis i “a Ge ay 5% se 41 2 Fakes .. se i 4 ta eh a I8- © Balbardie Seam— CoaL be oe se ss sy ee do A Parrot Coat... aS és oe ‘A . O 8 The coal seams mentioned in the tables are generally much split up with dirt and stone bands, as was shown in the previous * The figures in the first column are corrected for a dip of 25°, t Op cit. p. 372. 126 Carboniferous Limestone Series of Bo'ness and Bathgate District. detailed section. No parrot or cannel occurs with them in the Foulshiels and Blackburn district, but farther north, at Bathgate, it is found both with the Jewel, the China, and the Balbardie seams; but more particularly with the first and last named, which are in consequence often termed the Big and Little Parrots respectively. At the levels chiefly worked at present the Balbardie Seam is especially valuable, and is accompanied by a blackband ironstone which is wrought with the coal; but trials made at greater depths point to a deterioration in the quality of the seam towards the west. In the old days of crop workings, moreover, this coal does not appear to have been so much sought after as at present, for it was the Jewel, and not the Balbardie, which was then known as the “Parrot Seam.” The following section of the latter is quoted by Mr. Cadell from a report drawn up by David Landale in 1853, relating to the old Hilderston Colliery, situated about a mile and a half north of Bathgate. Ft. In. Roof, coal and stone in alternate layers 1 6 Coan as Oo 10 Stone .. 0 1 Coa 0 1 4 Stone .. 0 7 OAL a Oo 5 Stone .. 0 1 5 ft. 19 in Coat, free .. 1 4 Stone .. 0 Coan x 0 6 Coat, Parrot 1 #O Pavement, sandstone. At Kipps,* the most northerly of the collieries, which, in times gone by, have worked the Bathgate coals, the same seam was 2 ft. 9 in. thick, with 3 in. of parrot below, while in the present deep workings of Balbardie the parrot has disappeared altogether. The inconstancy of individual bands of parrot, compared with the coal - seams with which they are associated, is a noteworthy feature of this part of the field. ' Where there is no specially valuable parrot or ironstone, it is the Main Seam, as-its name implies, which is regarded as the most important coal in the field, but the other seams and the Jewel in particular are also extensively wrought. There are indications, it is to be feared, that the Bathgate volcanic rocks increase in thickness to the west under the outcrop of the Lower Coal Measures. Of course this development can only hold for a limited area, since the group is free from volcanic intercalations where it rises to the surface once more along the other side of the Lanarkshire basin, but it is a point which must not be lost sight of in forecasting the future development of the coal-field. To illustrate this increase we may, in the first place, compare the records which Mr. Cadell + quotes of the old workings near the crop at Hilderston and the journal of the bore put down half a mile to the west, close to the farmhouse. * For many details the reader should refer to H. M. Cadell’s paper. + “‘ The Carboniferous Limestone Coal-fields of West Leven Trans. Inst, Min, Engrs., 1901, vol. xxii. pp. 391, 392, Bo'ness and Bathgate Coal Group. 127 HILDERSTON COLLIERY. HinpErston Farm Bore. Ft. In. Ft. In Rep Coat (Balbardie) ee oil 59 InpEXx LIMESTONE .. ae A OT Strata eas es .. 386 0 Strata as is .. 75 6 Buack Coat (shaly) .. « 1 8 BALBARDIE SEAM « 2) ¥ Strata ae is .. 42 0 Strata dis “ss .. 88 O Two-FrEEt CoaL we we de) of SHaty CoaL— Strata a ..4ft.to 10 0 Coat, foul a wee, oly 3, Fippue Coat.. a ~~ 4 10 { Fakes and blaes wa AL9 Strata ate By .. 24 40 . (Coat, foul 6 sp. (a 10 Parrot Seam (Jewel) ws 6 0 Coaly fireclay and balls .. O 5 Strata ax a .. 42 0 Ash, conglomerate .. .. 80 5 Main Szay, with ribs - 38 O Limy fakes .. aS .» 27 «1 Limy fakes or ash .. . 74 4 Fakes and coal ribs (? Main) 5 3 Faky sandstone oe TZ 18 Grey fakes .. ss se 1 9 The “Limy Fakes” of the bore journal no doubt are igneous rocks of some description, either ashes or decomposing basaltic lavas. The same increase is shown, though in a very minor degree, in the deeper workings of the Balbardie Colliery; for the sediments, which, near the outcrop, intervene between the Index Limestone and the Balbardie Seam give place, farther west, to a vesicular olivine basalt which is probably a true lava flow. There is, however, no occasion to take a desponding view of the matter, for it will be shown subsequently, when the Upper Limestone group comes to be discussed, that the somewhat discouraging results of a deep bore (Vivian’s Bore), which started a little above the base of the Coal Measures south of the Bathgate fault, and failed to prove workable coals, are most probably due to faulting, and not to an increasing thickness of volcanic rocks to the west. E, B. B. THE KNOCK TO COCKLERUE (Sheet 31). The Bo'ness and Bathgate Coal group is replaced in this area by the voleanic rocks, with the exception of the narrow belt of coal- bearing sediments immediately below the Index Limestone. As already mentioned, these coals were formerly wrought at Hilderston and at Kipps. HW. B.M, COCKLERUE TO LINLITHGOW (Sheet 31). It does not seem possible that many of the sedimentary beds of the Bo'ness and Bathgate Coal group were deposited in this area ; but perhaps some of them occur here and there between the flows, and may in the future be revealed by borings. Up to the present time the results obtained by the few borings here made in the rocks in the position of the group referred to do not encourage further prospecting. One at Mains Maltings,a quarter of a mile N.E. of Kettleston, proved only “whin” of various colours to a depth of 70 fms., while another at Loch Mill traversed some 40 fms. of “whin” and a rock described as “fireclay,” which latter is prob- ably ash in reality, with sandy partings at intervals. The well at the Avon Print Mill, 400 yds. north of Linlithgow Bridge, after se 128 Carboniferous Limestone Series of Bo'ness and Bathgate District. passing a few feet of strata below the Index Limestone pierced 120 ft. of “whin.” Igneous activity continued until the close of the period during which the productive measures were being laid down else- where. INDEX LIMESTONE SPLINT COAL 3 2” CORBIEHALL COAL 1!" UPPER _IRQNSTONE 1'5" SEVEN FEET OR FOUL COAL SEAM & PARTINGS #710 Castrn a LAVAS "WITH, SOME ee a ae THIN, SEDIMENTARY Ne TARY PARTINGS tS 2 WESTER MAIN COAL 10"INCLUDING PARTINGS Pe JE ae ms SOME SEDIMENTARY 4 a ce aS eee TINGS ee as ED COAL Tat FIRECLAY COAL ra" LOWER IRONSTONE SIX FEET SEAM & 1” FASTER MAIN COAL SMITHY COAL 2'8" cee CARSEY LOAL CARRIDEN UPRER LIMESTONE Fie. 10.—Generalised Section of the Bo’ness and Bath- gate Coal Group near Bo'ness (scale 200 ft. to 1 in.). G. W. G. LINLITHGOW TO Bo’NESS (Sheet 31 in part). In the northern part of the area this group includes two chief divisions of coal-bearing beds —an upper and a lower—separated by thick bands of igneous rock, in places more than 300 ft. thick, most of which appear to represent lava flows. The total thickness of the group, includ- ing all the igneous bands excepting one, which occurs in the lower portion and is certainly of intrusive character, is about 1050 ft. This estimate is made from the section in the Snab Pit (No. 1), Kinneil, and from a boring put down near No. 9 Pit, Grange. The thickness of coal, including all seams not less than a foot thick, amounts in these sections to 294 ft. but it is to be noted that the Wester Main Coal, a seam which is in places thicker than any other but only occasionally found, is not represented in them, The accompanying generalised section shows the positions and names of the chief coals in the northern part of the area, where the coals are best developed. The strata between the Carriden Upper Lime- stone—the top bed of the Lower Limestone group —and the Carsey Coal are about 65 ft. thick, and include a considerable proportion of shale and various coals too thin to be worked. The Carsey Seam is also thin, but is reported to have been formerly worked near Carriden Glen, and two day-levels have recently been driven for short distances along it from the outcrop 200 and 250 yds. slightly south of east of Carriden Church. At the mouth of the eastern level a bright coal at least a foot thick is exposed. In the boring near No. 9 Pit, Grange, the section of the seam is as follows :— CoaL, strong Shale CoaL, strong coord et STO Shales with ironstone balls overlie the coal, and “fakes” and sandstone come below. In a sinking in No. 1 Pit, Carriden, the Carsey Coal is reported to be 32 in. thick, but much mixed with dirt partings: in a boring near Muirhouses (south of Bridgeness) it was 18 in., and it is said to be of the same thickness algo in part of the deep Kinneil workings, several miles west (the general direction of dip) of the outcrop, N Bo’ness and Bathgate Coal Group. 129 In the boring near No. 9 Pit, Grange, the distance between the bottoms of the Carsey and Smithy Coals is about 24 ft, which is somewhat larger than usual. In some places, for instance, the bore near Muirhouses just referred to, an impure calcareous band, said by Mr. Cadell to be an unfossiliferous marl, occurs a little above the Carsey Coal. The Smithy Coal is generally somewhat less than 3 ft. thick, but often of good quality, particularly in the southern part of the Kinneil workings, where it is at present being mined at a depth of 260 fms. below sea-level. It contains no anthracite as the name would imply, but is a gaseous coal and is classed as a good house and coking coal. In some parts of the Grange area it is too thin to be profitably mined, the difficulties of working being increased by the weakness of the roof which is formed of shale. But in other parts of this area it has been found by boring to be better developed, and new pits have lately been sunk to it both at Grange and Carriden. The roof of the seam has long been known as a pyritous richly fossiliferous shale. It has this character in the Kinneil workings, where the remains of Lingula mytiloides are especially abundant for an inch or two immediately above the coal, but are somewhat distorted. The seam has been worked on a small scale at an abandoned mine about half a mile N.N.E. of Upper Bonny- toun, where it has the usual roof and varies in thickness from two to three feet. The strata between the Smithy and the Easter Main Coals are generally about 80 ft. thick, irrespective of an- intrusive sill or laccolite which often occurs with them, but in the mine near Upper Bonnytoun the total interval, including a band of igneous rock, about 30 ft. thick, which is probably a lava flow, is about 66 ft. Mr. Cadell * states that a marine band, containing fish scales and Lingula squami- formis, occurs in a shale 2 fms. below the East Main Coal in No. 6 Pit, Grange, and that it has also lately been met with in the new sinkings (No. 1 and No. 2 Pits). From the loose blocks carried to the shore from these sinkings, Mr. Tait has collected the remains of various fossil fishes, which have been named by Dr. Traquair as follows :— Pleuroplax sp., tooth. Oracanthus armigerus Traq., teeth. Tristychius minor Ptl., spine. Megalichthys sp., scales. ELhizodopsis sp., scales. Strepsodus striatulus Traq., teeth. Colacanthus abdenensis Traq., plates. Elonichthys sp., scales. ELurynotus crenatus Ag., scales. Dr. Traquair states that “the above list is interesting as containing Oracanthus armigerus and Celacanthus abdenensis, characteristic of some Lower Carboniferous fish beds, which, like the present one, also contain abundant remains of Lingula squamiformis, Such beds are the so-called bone bed at Abden in Fifeshire, and the shale in * “The Fossiliferous Rocks of the Borrowstounness Coal Field,” Trans. Geol. Soc. Edin., vol. iv. p. 321, 9 130 Carboniferous. Limestone Series of Bo'ness and Bathgate District. connection with a seam of blackband ironstone of the “ North” coal worked at Niddrie in Midlothian.” (MS. note by Dr. Traquair.) In the eastern part of the coal-field, the East Main Coal—a clean house coal of very good quality—is from 32 to 44 ft. thick, and it is being extensively worked under the Forth both at the Grange (Bridgeness) and Carriden Collieries. Its somewhat splinty character enables it to be mined in large blocks; the roof is usually sand- stone. In the western part of the district, however, in the Kinneil Collieries, the quality is much inferior, and the seam is not worked. Immediately above a thin coal, which lies 2 or 3 ft. above the East Main in the Carriden Colliery, a band of shale, 2 or 3 in. thick, is crowded with Lingula squamiformis. This fossiliferous horizon was sought in vain in the Bridgeness workings and in the Fumace-yard Pit of Kinneil, though the thin coal is present in both laces, The interval between the East Main. and the Six-foot Seam amounts to about 40 ft. at Bridgeness and Carriden, and in the Snab Pit, Kinneil, to more than 53 ft. In the eastern part of the coal- field the Six-foot Seam is sometimes called the Foul Coal, being split up by partings of shale and fireclay to such an extent that it is not worked. Farther west, however, at Kinneil, it is mined—most of it as a steam coal—and the bottom part is an excellent Parrot, about eight inches thick, which is sent up separately from the rest. The usual section in the workings is— Ft. In. Faky sandstone .. he oe be “a ig as Shale sce es a ie ane ea ae cae Coat .. Ss a8 5 “ 8 a a 30:70) Fireclay .. 0 FREE Coan : a ae i ye bs ~ wa Fireclay .. Ma a es Ma ne “i .. O Free Coan .. as = : ey a Sclit (blaes) j te Se a ay a3 - 0 Coat, with a seam of Parrot varying in thickness from 0 tol0in. 1 Faky fireclay oa ue 4 6 8 6 4 7 4 2 Tn the Carriden Pit a coarse sandstone usually lies two or three feet above the coal, but sometimes comes down on or into the seam, in which case it is mixed irregularly with stripes of coal, as if the materials of the two beds had been jumbled together under water before consolidation. The interval between the Six-foot Seam and the seam of the Lower Parrot and Ironstone is but small. In the Red Coal Pit (a mile south of Bridgeness) it is only 6 ft. 3 in., which is less than usual. The different bands of ironstone, and those parts of the valuable gas coal that are thick enough to work, appear to have been all removed, but it is advisable to record the sections proved in some of the old workings. Mr. Cadell * gives the following section from the Red Coal Pit :— , Ft. In. Brown Ironstone a ae 1 0 Fireclay with ironstone nodules. . <8 . O 2 Coat, Parrotand CANNEL .. a as ae . 0 9 BLACKBAND [RONSTONE ais Be aus 0 3 Coarse fireclay and ironstone nodules .. 0 10 * Trans. Inst, Min, Eng., 1901-2, vol. xxii. p. 379. Bo’ness and Bathgate Coal Group. 131 He also states that the section in the Bridgeness workings in 1901 was as follows :— Ft. In. Hard shale and kennel os Common or Craw CoaL ‘ ve LD Shale . lftto3 0 Coat, Parror .. . lfttol 2 Shale and ironstone nodules The seam was also formerly worked from the Schoolyard Pit, Bo’ness, underneath the sea opposite Bo’ness harbour and dock, where it gave the following section :— Ft. In. Common CoaL .. Se ia a 5 .. 8in.to 0 10 Parrot Coat .. - 2 ie .. lft3in.tol 7 BLACKBAND IRONSTONE ne as aii .. 3in.to 0 10 In No. 9 Pit (Kinneil), about 250 yds. north of Bonhard House, the section showed the following beds :— Ft. In. Shale Pe a e4 a Pe ee .. 10 O Coarse IRONSTONE .. fe ais = a - 1 6 hale oe oa es 6 ah es sa 8 Foun Parrot Coat .. bb af ei ee . 6 8 Brownstone IRONSTONE .. oer ea .. 10in.to0 3 Sandy fireclay .. ie i ae .. 2intoO0 8 Parrot CoaL .. “4 .. 8in.tol 6 BLAcksToNnE IRONSTONE B (inferior i in quality) -.. 8in.to 0 10 Dross Coat .. ; x - O 6 Coarse fireclay .. ve ia Be .. 9in,tol O Dross Coat .. as os 2ft.2into2 6 Black hard Cy ‘sandstone. os a -. 0 Dross or Foun Coat . as B6 oni a se. a Sandstone ‘i It is stated that, in the abandoned pit near Upper Bonnytoun, this seam is hardly represented, though the ironstone was of good quality farther north-east between Bonsyde and Bonhard Mill. In the Kinneil Collieries the position is marked by an impure ironstone, 2 in. thick, and some thin bands of rough coal which are too much mixed with layers of stone to be workable. The shale above the brownstone portion of the seam is said to have been richly fossiliferous in No. 9 Pit, Kinneil, and the blocks of parroty shale in the waste heap at the old pit mouth contain abundant specimens of Naiadttes obese. The same fossiliferous horizon was also found in the Red Coal Pit, but it does not appear to be represented in the Kinneil and Carriden workings. Mr. Cadell states that in No. 5 Pit, Grange, a band containing a similar assemblage of fossils occurs a few feet lower in stratigraphical position. The beds between the Lower Parrot and Ironstone Seam and the Red Coal are about 97 ft. thick in Pit No. 6, Grange, and the upper portion includes a thin coal called the Fireclay Seam, 14 in. in thickness, and is underlain by a fireclay, 5 ft. 4 in. thick, which was formerly worked. The Red Coal is now being mined under the Forth from No. 6 Pit, Grange, where it is 3 ft. thick and is classed as a gas or house coal of second-class quality ; above the seam comes a faky blaes (sandy shale), 9 in, thick, and then a hard sandstone which makes durable roofs 132 Carboniferous Limestone Series of Bo'ness and Bathgate District. for the underground roads. This sandstone is rather more than 40 ft. thick, and is quarried along the outcrop half-a mile south of Grangepans, where it is surmounted by a band of igneous rock that probably represents a lava flow. As Mr. Cadell has pointed out * this sandstone is not represented near Upper Bonnytoun, the Red Coal being there separated from the overlying lava only by a little shale—sometimes less than 6 in. thick. The coal is exposed at the mouth of an old day-level in this locality, where it is only 18 in, thick and mixed with bands of dirt, but it is reported to be thicker and better within the mine. In the Snab Pit shaft No. 1,a seam, composed of 6 in. of coal at the top and 14 in. at the bottom, separated by 16 in. of white calm (clay), lies immediately below a thick bed of igneous rock. This seam may possibly be in the position of the Red Coal, but Mr. Cadell regards it as a representative of a higher seam—the Wandering Coal, to be shortly described—because a band of igneous rock, 4 ft. 6 in. thick, comes almost immediately below it (see Fig. 10). Most of the sedimentary partings separating the different bands of igneous rock that come between the upper and lower coal-bearing beds of this group cannot be traced satisfactorily, being either thin or deeply covered by drift. In the Kinglass Pit (also called the Mingle Pit, about 370 yds. slightly west of south of North Kinglass) the two lowest whinstones are separated by a thin hard sandstone, called “red-stone,” and above them come 30 ft. of shale followed by another bed of whin, about 20 ft. The “ Wandering Coal” seems to have been found almost by itself, apart from any other sediment, in a great mass of whin and to have been formed of a local accumulation of vegetable matter, washed down into an irregular hollow on the surface of the underlying lava, which was shortly covered again by another flow. It was first met in No. 3 Pit, Kinneil (about 230 yds. south-east of the Newtoun cross roads), where it was 94 ft. thick, and of excellent quality, but disappeared rapidly, in distances varying from 50 to 100 yds., in all directions from the shaft bottom. In No. 18 Pit, Kinneil (Lothians Pit), its distance above the Red Coal ig 158 ft. This seam was also found in No. 13 Pit, Kinneil (420 yds. W.S.W. of No. 3). Above the igneous material forming the roof of the Wandering Coal comes another band of sediments, including the Wester Main Coal, which also seems to have been entirely or almost entirely worked out, though it was thicker and much more widespread than the Wandering Coal. The thickness of this band averages perhaps 30 ft., but it is much thicker in some places, for instance in the Burn Pit (near North Bank), and in the Mingle Pit (nearly half a mile north- west of North Bank), which went down 144 ft. before it reached the coal and pierced no whinstone above it. The following section is taken from No. 18 Pit, Kinneil (Lothians Pit) :— Ft. In. Freestone roof .. Pa 2a ae i . 400 0 Shale te ws bo A za sa . O 9 CoaL .. as ai} oe ae x ie e- 34 Fireclay .. ae vit is ws a6 . 1 0 * “ Volcanic Rocks of the Borrowstounness Coal-Field,” Trans, Edin. Geol. Soc. 1880, vol. iii. p. 322, Bo'ness and Bathgate Coal Group. 133 Coat .. Oe Calmstone. . CoaL.. ot Blaes CoaL .. Fireclay ate we a ae e:3 ers Greenstone (whin) ies 2 oes a sx 6 OM Oe Hee DOwWH RoR’ The total thickness of the seam, including three partings, is here more than ten feet, which was, however, much exceeded in other laces. : The outcrop of the seam is said to pass about 150 yds. east of Bo’ness Railway Station and thence into the sea at the old harbour close to the docks. Near, and for some distance east of, North Kinglass, a group of large “sits” indicates the position of the old shallow workings. The seam was mined also in some old crop pits a few hundred yards south-west of North Bank. On the south side of the large east and west fault with a downthrow to the north that passes a third of a mile 8.S.W. of North Bank, the seam must run along the narrow slack extending in a S.S.W. direction to a locality 150 yds. slightly west of north of the monument on Bonnytoun Hill. A coal seam and old crop workings have lately been disclosed in this locality, and a boring proved the following section :— 9) or eS i=] Surface CoaL .. Fireclay Coat .. ev Dark fireclay Harp Burnt Coan Fireclay .. Soft whin .. BNF aATNPNONGe i COMOOCOMWORDW bo A seam, said to be 7 ft. thick,* and with a roof and pavement of whinstone, was formerly worked in a shallow pit about 350 yds. E.N.E. of Swordie Mains, and is in all probability the same coal. In bore No. 8 Muirhouse, the seam was found at adepth of 150 ft. below the top of the whin and showed the following section :— Ft. In. Fireclay and Coal .. 3°¢«C7 Foun Coan = fe Oa) Fireclay and Coal .. 0 10 Foun Coan st 2 5 In the Snab Pit (No. 1) the whinstone, which comes above the supposed position of the Wester Main Seam, is no less than 265 ft. thick. It is succeeded by a parting, 5 ft. 6 in. thick, of shale, coal and “marledstone,” overlaid by another bed of whin, 20 ft. thick, and the upper coal-bearing sediments. No seam in these upper beds is at present worked. In the Snab Pit (No, 1) the Seven-foot Coal—which lies about 74 ft. above the bed of whin last mentioned—is called the Foul Coal or the Four-foot Coal, and its usual thickness is about 4 ft. 10 in., including a 4-in. parting of shale near the middle (see Fig. 10). * This estimate probably includes various partings. 134 Carboniferous Limestone Series of Bo'ness and Bathgate District. The Upper Ironstone Seam is only 4 ft. 10 in. above this coal, and its average section is— Ft. In. CoaL 1 2 Stone-rib a 0 9 BLACKBAND IRONSTONE .. 1 5 It was formerly extensively worked from the Snab Pit, as far as 1000 yds. south-west of the Newtoun cross roads, for the sake of the ironstone, which was smelted at the Kinneil Furnaces. The Index Limestone does not seem to have been recognised in the shaft of the Snab Pit No. 1. In the recorded section of this shaft a limestone, 15 in. in thickness, is indicated just below a band of whin- stone, 51 ft.,and above this whinstone comes a foul coal, 13 in. thick, overlaid by another bed, 54 ft, which is termed “bastard green whin.” It seems possible that the so-called limestone may be a veined portion of whin, and that the “bastard green whin ”—which is 122 ft. above the Splint Coal—may be the Index Limestone. In _the cliff behind Bo’ness Distillery the interval between the Index - Limestone and an underlying bed of igneous rock, about 24 ft. thick, is uearly 10 ft. A coal, from 2 to 4 in. thick, occurs 2 or 3 ft. beneath the limestone, and below this coal there is a fireclay, which was for- merly used for brickmaking. The igneous mintenal rests on a coarse sandstone about 11 ft. in thickness. The upper coals are found only in the eshte part of the area, the dip being generally in a westerly direction, though with many local variations, and at angles varying from 7° to 22°. In the Grange (Bridgeness) workings about 400 yds. south-west of Bridgeness Pier a gentle anticline strikes nearly north and south, and continues some distance inland where it affects the outcrop of the lava that overlies the Red Coal. West of this anticline comes a shallow syncline followed by another parallel anticline, the axis of which passes about 400 yds. east of Bo’ness Docks. Still farther west the dip is generally westward, but in the north-east portion of the Kinneil workings the beds are sometimes flat or inclined north-east. In the area near Bonside and Bonhard Mill, where the beds are for the most part drift covered, the Lower Parrot and Ironstone Seam* has been worked at levels considerably lower than the surface position of this seam farther west, and it seems probable that this is due to a local change of dip towards the east. The largest fault known landward is the east and west dislocation passing about 700 yds. south-west of North Bank, where the down- throw is to the north about 20 fms. Its course westward is un- certain, but in the workings in the Upper Ironstone, 400 yds. west of Borrowstoun Mains, a fault was proved, striking nearly east and west and with a considerable downthrow to the north, which may represent a continuation of it. The occurrence under the foreshore and the Forth of certain coals of the lower division considerably east and north of their outcrops inland, is mainly due to the presence of two other faults which also strike nearly east and west and have a downthrow to the north. At Bridgeness the throw of the southern fault amounts to about 32 fms., while that of the northern one is about 12 fms., but the beds on the north side dip to the north for a distance of 700 yds., so that, about Bo'ness and Bathgate Coal Group. 135 480 yds. off Bridgeness Pier, the East Main Coal is 569 ft. below sea- level. The workings have proceeded about 450 yds. farther seaward across a shallow basin, at the other side of which the strata dip in a southerly direction. In the Carriden Pit the inclination of the northern fault to the north is well seen, and is unusually low—being only 45°. Tn the Kinneil workings neither of these faults can be recognised with confidence. It seems probable that they both decrease west- wards, and perhaps unite about a third of a mile west of Bo'ness Railway Station. All the Bo’ness Coal seams appear to diminish in thickness on the south side of a line drawn east and west about a mile and a half south of the Forth, while the volcanic rocks increase. Pits have been worked for short periods in various places on the south side of this line, for instance, near Upper Bonnytoun, at Muirhouses (about a mile north of the west end of Linlithgow Loch), and near Balderston —rather more than half a mile W.S.W. of Swordie Mains—but none of these has been successful. In the Muirhouse Pits No. 1 and 2, two coals, separated by 6 fms. of coarse freestone, were mined, but neither is much more than 2 ft. thick. The lower seam is about 35 ft. above the top of the thick whinstone that underlies the upper coal-bearing beds. About 120 yds. south of Swordie Mains a coarse yellow freestone, lately exposed, probably represents the horizon just alluded to, and is of considerable interest, as Mr. Cadell has found it to contain small grains of garnet in great abundance. Subsequently Mr. Grabham found in it tourmaline, rutile, zircon, magnetite and leucoxene. In No. 3 Pit, which is some distance west of the others and no doubt in higher beds, a band of good cannel coal, 5 or 6 in. thick, was met with, which lay under, and seemed in places to be partly replaced by, an ironstone of good quality. No satisfactory information has been obtained about the Balder- ston Pit, but it must have started in beds considerably below the Index Limestone. It is said to have been 12 fms. deep and to have reached a coal, 3 ft. 8 in. thick, which was mixed with dirt partings. A number of shallow bores have been put down in this locality, but it is doubtful whether their positions have been accurately described in the journals. In bore No. 12 Balderston, a coal, 4 ft. thick, was met at a depth of 13 fms., and in bore No. 11 Balderston, a coal, 3 ft. 10 in.,, at 8fms. It is probable that the coal in each bore belongs to one seam, and is higher in position than the seam mined in the old pit, but thick beds of volcanic ash occur in the vicinity, and the geological structure is far from clear. Various bores put down near the north-west end of Linlithgow Loch have pierced alternating bands of igneous and sedimentary rock, the latter of subordinate thickness, but containing various coals, some of which may represent the Red Coal, Six-feet, Kast Main, and Smithy seams, which were formerly worked in the old mine near Upper Bonnytoun. It is not possible to correlate individual seams with confidence, but a seam of foul coal, 2 ft. 10 in. thick, which was found at a depth between 62 and 63 fms. in the bore No. 1 Loch- house (about 300 yds. N.N.E. of Loch House), is generally con- ‘sidered to represent the Red Coal. In bore No. 1 Parkhead (300 yds. 136 Carboniferous Limestone Series of Bo’ness and Bathgate District. south-east of Parkhead) a foul coal, 2 ft. thick, at a depth of 34 ft., is perhaps in the position of the Smithy Coal. The boring No. 6 Kinneil, put down near the Little Mull, three- quarters of a mile W.N.W. of the west end of Linlithgow Loch, affords evidence that, in this locality, the volcanic rocks increase in thickness for a certain distance in a westerly direction—towards the dip—and that, concurrently, the coals die out or become valueless. The bore starts in a volcanic ash some distance below the Index Limestone, and is 691 ft. deep. The first sediments met with, at a depth of 490 ft., are perhaps on the horizon of the Wester Main Coal, but they include no coal and are only 7 ft. thick. The rocks pierced below this are evidently to a large extent of igneous origin and do not comprise a single coal seam. In hope of finding the Bo’ness coals in good condition on the western side of the Kinneil workings, Messrs. W. Baird & Co., of Bothwell Collieries, have lately made a deep boring near North Hainings, in a position rather more than a mile W.S.W. of the deepest part of the Kinneil Collieries. The results are most dis- appointing. The bore enters the Index Limestone at 45 fms. and proceeds to a total depth of 425 fms. The position of the Seven-foot Coal is recognisable at a depth of about 32 fms. below the Index Lime- stone, but below this point there is an abnormally large proportion of whinstone and volcanic ash. The characteristic roof of the Smithy Coal was not recognised, but it seems certain that the whole of the rocks representing the position of the Bo'ness Coal group was pierced, for, at 394 fms, a limestone, 15 in. thick, is recorded, the core of which is a dark grey limestone of good quality and includes fragments of crinoid stems. A higher bed, at 268 fms., is also recorded as a limestone; it is a foot thick, surmounted by 22 in. of calcareous calm and fakes, and was described by the borer as a blue limestone. C.T.C. Upper LIMESTONE GROUP. WOODMUIR AND FOULSHIELS AREA (Sheet 31). At the south-east corner of Sheet 31, the Index Limestone is never seen at the surface, but between Woodmuir fault and Mosshall its position has been traced by numerous bores. It is usually about 44 ft. thick and is overlaid by blaes and balls, from 12 to 18 ft. sueceeded by a thick white sandstone. A quarry was opened three-quarters of a mile south of Breich Station in the upper portion of this sandstone, but the rock proved to be inferior and soft, with a peculiar concretionary structure. Between the Woodmuir _and Leven Seat faults the position of this limestone has not been proved. The Arden (Gair) Limestone is reported to have been wrought in a small quarry at the cross roads west of Hendreys Course, but the excavation is now grassed over, and this limestone has not been recorded in any of the bores to the north where it might have been expected to occur. For over two hundred years the Castlecary (Leven Seat) Lime- Upper Limestone Group. 137 stone has been wrought on the east side of Leven Seat. At first the workings were open-cast, and latterly the stone was mined. The underground workings extend for half a mile to the west of the cairn, This limestone is about 9 ft. thick and is overlain by an oil-shale 15 in. in thickness, of excellent quality, which was mined with the limestone. For many years before the advent of the oil-shale industry this tough leathery shale was sold throughout a wide area and used for cover plates for road culverts, and although less than one foot thick these plates can carry a heavy traction engine. When paraffin oil was first produced from oil-shale, this seam was retorted and the oil refined near Greenburn, and latterly the crude oil was sold to some of the larger refineries. In the mined area the limestone was best at the outcrop, and continued good till it was covered with from 20 to 24 fms. of strata. At this depth it became rapidly poorer in quality and also thinner, probably owing to partial solution by percolating water. On the north side of the Bank Head fault this limestone is only represented by a band of thin limy shale below a sandstone roof, but its position has been determined by the outcrop of the Curly Ironstone which lies 84 fms. above it. At Blackhill, Breich Water, a grassed-up quarry with kilns doubtless indicates the outcrop of the limestone, and from this point to Mosshall its position has been determined by protraction from known outcrops. J.8. GW. THE BATHGATE AREA (Sheet 31). Between the river Almond and Durhamtoun there is very little accurate information about the Upper Limestone group as a whole, though the lower portion, including the Index Limestone, has several times been passed through in search of the underlying coals. It is interesting to find, however, that the oil-shale, over- lying the Leven Seat Limestone in its typical district, has been proved by boring near Durhamtoun, though in an unworkable condition. Northwards again between Durhamtoun and Hilderston, while there are several deep bores traversing the whole of the group, there is only a single surface exposure of any portion of it. This occurs in a cutting of the mineral railway leading to the Balbardie Colliery, where the Index Limestone, 3 ft. thick, is seen to contain Productus latissimus and other shells, and to be overlain by 15 ft. of grey fossili- ferous shale passing upwards into faky sandstones, which also in their bottom layers contain casts of Productus and other marine organisms. The deep bores alluded to, which occur in the Bathgate district, prove two points of importance, first, the presence of a volcanic horizon between the Index and Calmy (Arden) Limestones; and, secondly, the rapid variation in thickness of the group. The four chief bores are as follows: Walker’s Bore at Little Boghead— Vivian’s Bore starting a little above the base of the Coal Measures, slightly south of the Bathgate fault, less than half a mile west of Walker’s Bore—Easton Bore, slightly over half a mile N.N.W. of Vivian’s Bore—and Hilderston Farm Bore, a mile and a quarter 138 Carboniferous Limestone Series of Bathgate and Bo'ness District. N.N.E. of the Easton Bore. An abstract of these bores is given in the following table :— Walker’s. | Vivian’s. | Easton. | Hilderston. Ft. In.| Ft. In.| Ft. In.} Ft. In. Leven Seat Limestone 5 69 7 1 4 6 4 2 Strata .. os ee ee 170 +O 247 «~0 158 O 139 #0 Calmy Limestone .. aa 4 2 5 6 4 0 1 6 Strata with Whinstone .. | 288 O 2 480 0 297 0 Index Limestone... as 4 4 = 4 0 4 Il 472 3 a 650 6 | 446 7 The 80 ft. of increase between the Leven Seat and Calmy Limestones in Vivian’s Bore, as compared with Walker's, is due to an expansion of the shaly portion of the series and not to the development of grits or sandstones. It should be stated also, that Vivian’s Bore went down 747 ft. beneath the Calmy Limestone without reaching any recognised representative either of the Index Limestone or the seams of the coal-bearing group. Considering the position of the bore, and its great depth, it seems probable that it passed through the Bathgate fault, and that the Index Limestone and the underlying workable coals have thus been cut out of the section which it traversed. The proportion of “whin” proved in Vivian’s Bore is certainly too small to account by itself for the absence of the limestone and coals from the bore record, and if the Bathgate fault has not been pierced, it is necessary to regard the whole thickness as belonging to the Upper Limestone group—an unlikely interpretation. At all events it would be unwise to be deterred by the result of this bore from further exploration of the field underlying the Coal Measures. The following details are taken from Walker’s Bore :— Ft. In. Leven Seat LIMESTONE .. i es 8 . 5 98 Blue blaes. . bn fe a a3 = se @ 9 Kingle stone i 5G es as os . O 6 Light faky fireclay ee i ae zs .. 17 10 Sandstone. . a oe és Se ie .. 16 6 Fakes aa ai or ia ts ws . 389 #1 Sandstone with kingle rib near middle ed .. 387° 6 Fakes and blaes .. acs oe sc a . 56 3 ARDEN or CaLmy LIMESTONE v6 ae a a Sandstone. . i a2 5 of at . li 8 Grey fakes ne ia ssi =o 8 .. 14 10 Sandstone. . aes on a re 2 i FS Kingle.. i oe i vs ae wD 6S Grey fakes and hard ribs hs Pe a -. 2 8 Sandstone.. sca és a re is we 11 4 Fakes and hard ribs... as ae nh .. 17 10 Fakes and sandstone .. Pe ds wl se 12° 9 Whinstone, soft above .. v sey ei .. 86 6 Dark grey fakes .. oy os saa ass - 4 8 Carry forward .. 325 1 Upper Limestone Group. 139 Ft. In. Brought forward .. 325 1 Whinstone ‘ie “a sh ea Ps . 40 1 Dark fakes se ne ae ale as ~ 2 4 Coat, foul a as oe by aa a . O 4 Bands of sandstone, fakes and blaes .. ak .. 81 6 Blue blaes ea Pr $4 oss i . 19 #O Inprx LimEsToNE .. as a i aig - 4 4 472 8 E. B. B. HILDERSTON TO COCKLERUE (Sheet 31). The Index Limestone is at present exposed at the top of a small quarry on the west side of the road, and half a mile east of Hilderston Farm. The section is as follows :— Ft. In. Argillaceous limestone in bands, with Productus latissimus 3 6 Blaes.. sds <2 a4 8 4 0 CoaL sts ne i 1 0 Fireclay and shale .. 6 0 Sandstone and shale 5 0 Coan : ai Pn a 1 3 Sandstone, base not seen .. 10 0 In quarries on the east side of the road, two other thin coal seams are exposed. The section given above is the only exposure of the Upper Lime- stones until we reach the old workings of the Castlecary Limestone at Lochcote. This limestone has been wrought on the north side of the Kipps dyke, but, on its south side, the great Torphichen sill transgresses to a lower horizon and prevents the outcrop of the Castlecary seam. The outcrop of the Arden Limestone is not known south of Carribber Glen. H. B. M, COCKLERUE TO LINLITHGOW (Sheet 31), The Index Limestone is best seen in the Avon north of Linlithgow Bridge, where the following section occurs, the lowest bed of which has already been described :— Ft. In. Sandy shale Limestone ne 0 66 Shale with fossils 320 Limestone P 2 6 Shale on 2 O Coat .. - 0 3 Ash Productus latissimus is very abundant both in the limestone and in the fossiliferous shale, in which it occurs in the position of growth. This bed is not seen at the surface between the Avon and Cocklerue, but it has been recorded in bores both at the Avon Mills and near the road, 150 yds. west of Linlithgow Bridge. About 300 yds. south-west of Manuelhaughs a bore, after passing the Arden Limestone, traversed a section very similar to that of the second 140 Carboniferous Limestone Series of Bo'ness and Bathgate District. bore mentioned above, agreeing in the position of several small coals, the characters of the beds between these seams, the thickness of a bed of “whin” and the distance between it and the main “whin” below. If the correlation of the rocks that seem to correspond in the bores is correct, the Index position has been passed in the bore near Manuelhaughs without any limestone being recorded. Farther south the Index Limestone probably sweeps to the south-east, parallel to the next higher limestone, being recorded close to the surface in a boring at Belsyde, and also the one reported to have been found a quarter of a mile north of Cocklerue, below dolerite which was quarried for the reservoir close by; from here it strikes southward with the associated sandstones, ashes and lavas, which occur above it. The strata above these lavas consist chiefly of sandy shales and some fireclays. In the Avon gorge east of Muiravonside, as we approach the Arden Limestone, some ashy sandstones are found which have yielded the following fossils: Cup corals, Productus, Orthotetid shells, Fenestella, Orthoceras and Trilobites. The Arden Limestone is well seen in the Avon at Woodcockdale, where it is repeated by a small fault; here it overlies some plant- bearing shales, and, as at Carribber Glen, occurs in several bands with shaly partings between. At Easter Carribber the following section of the limestone is seen on the south side of the glen :— Ft. In. Dark sandy shale . Impure limestone 0 6 Shale oa). 0 6 Compact limestone 3 0 Shale parting Limestone. . 0 8 Shale The limestone is an impure, dark-blue pyritous bed giving a white surface on weathering. Though the outcrops are few, its position has been defined by borings west of the Avon. In Car- ribber Glen at least 50 or 60 ft. of dark-blue shale rest directly on the limestone; on the north bank of the river these shales are again seen, but the limestone itself has not been noticed in place. North of the Canal aqueduct, beds in this position become more sandy. The uppermost limestone of this series, the Leven Seat or Castlecary, is well exposed in the Avon, just below the Canal aqueduct, resting on sandy shales and surmounted by sandstone. It occurs in several distinct bands, with a total thickness of 5 ft. and is very dolomitic, hardly effervescing with acid, while its specific gravity is 290 and indicates the presence of some iron. It is not now seen in Carribber Glen, but the old quarries on the south side indicate its position. On the north bank a good section of the strata above the blue shale overlying the Arden Limestone can be seen, but the dolerite intervenes before the topmost limestone is reached. From the glen southwards the outcrop is well marked by old workings as far as Bowdenhill, where the limestone is about 7 ft. thick, almost Upper Limestone Group. 141 black, crinoidal and effervesces freely *—in strong contrast to its behaviour only a mile farther north. G. W. G. LINLITHGOW TO BO'NESS (Sheet 31). In this area the group includes, besides the Index, the Arden (Calmy or Dykeneuk) and the Castlecary (Leven Seat) Limestones, another band (between the Index and Arden) which will be called the Kinneil Mills Limestone. From evidence obtained from bores the total thickness of the group appears to be about 830 ft. The Index Limestone is exposed on the west side of the Avon, west of the Little Mill, and in various places at the sides of the stream that joins the Avon from the north a quarter of a mile north-west of the Mill. It averages about seven feet in thickness, including various bands of calcareous shale, and is characterised by the abundance of Productus latissimus. At the base there is a calcareous mudstone about a foot thick, with a somewhat ashy aspect in parts, which contains abundant remains of Fenestella, but very few of Productus, and, below this horizon, there is a coal about seven inches thick. In one of the exposures, a band near the top also seems somewhat ashy. In the cliffs behind the Bo’ness Distillery the section is somewhat as shown below :— Ft. In. LIMESTONE ‘ ye 2 3 Calcareous shale .. 0 9 LIMESTONE a es 2 or as oe 1 #O Crinoidal shale with small nodules of limestone 3 0 The exposures in these cliffs are imperfect and have not provided many fossils, but some blocks, which were formerly removed from this locality to a field near Kinneil Railway Station and are now considerably weathered, are seen to be full of Productus latissimus. At the distillery a bed of shale, about eight feet thick, comes above the limestone, and is in turn overlain by a sandstone, which in the Snab Pit (No. 1) shaft is 79 ft. in thickness. This sandstone is exposed at the back of the 20-ft. raised beach west of the distillery, and is a good building stone, largely wrought in the Maiden Park and Deanfield quarries, ete. In the same shaft just below this thick sandstone a bed of fireclay was formerly extensively mined for making firebricks; and, about 144 ft. above the sandstone, a coal, sometimes called the Mount Hunger Coal, is recorded, 2 ft. 3 in. thick, including a 3-in. shale parting near the middle. Near the Avon the thickness of the strata, including a band of igneous rock that probably represents a lava flow, between the Index Limestone and the Kinneil Mills Limestone is probably about 250 ft., but near the Forth the thickness seems greater, for the journal of the North Hainings boring, already alluded to, shows a limestone 22 in. thick, which appears to represent the Kinneil Mills bed, and is 375 ft. above the top of the Index. * It is also remarked by Charles Forsyth (Trans. Highland and Agric. Soc. Scotland, 1846) that on account of its freedom from magnesia it is particularly suited for agricultural purposes, 142 Carboniferous Limestone Series of Bo’ness and Bathgate District. The Kinneil Mills Limestone is only: exposed in one place, on the north side of the Avon about 100 yds. west of the bridge at Kinneil Mills, where it is crowded with Productus latissimus and has a considerable resemblance to the Index Limestone, but it is only 3 ft. thick—hardly half as much as the Index Limestone at the Little Mill—and rests almost directly on an 8-in. coal seam. There is no bed below it like the shale with Fenestella which occurs below the Index. In a boring put down at the roadside about 400 yds. E.N.E. of Dykeneuk, a limestone, 22 in. thick, including a 7-in. parting of blaes, was met at a depth of 17 fms. and probably represents the Kinneil Mills Limestone. It is too near the surface to be the Index, for the bore appears to start in beds only about 200 ft. below the Arden Limestone, and in the North Hainings Bore the interval between the Arden and the Index Limestones is as much as 578 ft. A few feet below the Arden (Calmy or Dykeneuk) Limestone, a coal, called either the Wood Coal or the Upper Hirst or the Janet Peat, has formerly been extensively worked in shallow pits near Dykeneuk and in Kinneil Woods (whence the name “ Wood Coal” ° is said to be derived). On the south side of the railway line, 250 yds. east of Dykeneuk, this coal is exposed. It is-at least 2 ft. 8 in. thick, and lies about 20 ft. above another rather thinner coal. In the journal of bore No. 1 Kinneil, put down about 300° yds. south-west of Dykeneuk House, the Wood Coal is described as a foul coal 24 in. thick, and the underlying “soft” coal is 18 in. thick. In the journal of No. 5 Kinneil Bore, 300 yds. north of East Kerse Mains, the Wood Coal is described as a good coal 3 ft. thick. The Arden Limestone was formerly extensively worked near Dykeneuk, along the outcrop south of the railway and in day levels. It is not exposed in this locality now, but in the boring just referred to the following section was found :— 7 Ft. In. Dark blue blaes .. exh and “fe a ne LO: <2 LIMESTONE a a8 ae ee ne iS iis 1 8 Blue blaes : 111 LIMESTONE ee ne sf ee wa oe . 1 8 Soft blaes .. an al af hes re ae “Oe 8? LIMESTONE 1 oi i re re ie ‘ 1 O Blue fireclay and blaes .. 30041 This limestone is seen in the Avon in three places, between half a mile and a quarter of a mile west of Kinneil Mills, once on the north side of a powerful east and west fault, and twice on the south side and considerably disturbed. The fault throws down to the north and is no doubt a continuation of the dislocation which crosses the river 300 yds. above the viaduct. None of the exposures are complete, but the bed is evidently of good quality, about six or seven feet thick, and overlain by a considerable band of shale, at least 40 ft. in thickness, containing various thin calcareous seams and lenticles. In the North Hainings Bore the distance between the Arden Limestone and the thin limestone that is supposed to represent the Kinneil Mills Limestone is about 188 ft., and the former bed is 74 ft. thick, including two shale partings. Upper Limestone Group. 143 A boring, No. 3 Kinneil, put down 650 yds. W.S.W. of East Kerse Mains, proved the strata which there intervene between the Arden and the Castlecary Limestones to be more than 240 ft. thick. Some distance above the shale overlying the Arden we find a thick rather coarse-grained massive yellow sandstone, which has been quarried at the roadside near North Hainings, and is also well seen in the Avon. On the south side of the railway line, about a quarter of a mile south-west of Dykeneuk, a peculiar ferruginous calcareous sandstone, about a foot and a half thick, occupies perhaps a nearly middle position between the Arden and the Castlecary Limestones. The Castlecary (Leven Seat) Limestone is not now well exposed in any part of this district, but it was formerly extensively mined near the coast at Craigenbuck (300 yds. 8.8.W. of North Hainings) and also 150 yds. east of the Avon viaduct. The following section is recorded in the last-mentioned locality :— LIMESTONE, grey crystalline. . Shale pe ‘ iy LIMESTONE, concretionary LIMESTONE, compact blue Shale, blue and dark grey oe Shaly sandstone and dark shale ROHKone OOrraQrt Part of the bed now visible near the Avon is coarsely crystalline and evidently dolomitic, having a specific gravity of 2°86. In the railway cutting a quarter of a mile S.S.E. of North Hainings the limestone is also exposed, dipping nearly north, probably under the influence of some fault, and is again dolomitic with a specific gravity of 2°81. The underground workings near the Avon extended 600 yds. north-east from the outcrop on the north side of the river, and the bed probably extends considerably farther in this direction before it curves and strikes north-west or west, under the influence of the fold which is indicated a little east of Dykeneuk. In the Avon the general inclination of the beds is north ‘of west, often at angles varying between 10° and 20°, and for some distance to the north the crops of the beds must run north-east, but south-west of the Little Mill the dip of the sediments is south-west, and the strata near the thick volcanic ash must be rather sharply bent. The southerly dip on the west side of the locality where we find the change of strike referred to in the preceding paragraph is well seen in the steep bank at the back of the raised beach, and continues nearly to East Kerse Mains, where the inclination is south-west. For about a quarter of a mile west of this farm the dip appears to continue south-west, after which we enter an area with varying dips, which is perhaps crossed by some important faults. The exposure of the Castlecary Limestone in the railway cutting near North Hainings is perhaps near the north side of a fault with a considerable downthrow to the south, for it is inclined to the north, and the beds farther south should be lower in the stratigraphical sequence if such a dip continued without any faulting. In a boring, however, put down near the railway 700 yds. farther south, this limestone was again found at a considerable depth. In an old boring put down in the Willow Bog—the alluvial land 144 Carboniferous Limestone Series of Bathgate and Bo'ness District. about 170 yds. south of Inveravon—the base of a limestone, 5 ft. 7 in. thick, was found at 32 ft. This band, overlain by 17 in. of limy fakes, probably represents the Castlecary Limestone, and, to account for its high position at the Willow Bog, it seems necessary to suppose that it has been thrown up to the north by a fault of considerable amount, perhaps about 100 ft., which may pass through an obscure area a little south of the old boring. The supposed fault may continue in an E.N.E. direction past the south side of the lime- stone outcrop in the railway cutting. ‘ In boring No. 5 Kinneil, 300 yds. north of East Kerse Mains, the base of the Arden (Dykeneuk) Limestone was found at a depth of 140 ft. (and 64 ft. below the rock surface), The beds exposed near East Kerse Mains are considerably above this limestone in the strati- graphical sequence, but it is considered probable that the limestone comes to the surface about half-way between the farm and the site of the bore, dipping south or south-west like the other beds exposed in the locality. It seems probable, therefore, that a fault with a considerable downthrow to the north passes between the site of the bore and the farm: the direction of the supposed fault is very doubtful, but in the map it has been drawn W.S.W. c. 7. CARBONIFEROUS VOLCANIC Rocks OF THE BATHGATE, LINLITHGOW AND Bo’NEss DISTRICT. The voleanic rocks now to be described are confined to that part: of the Lower Carboniferous formation which occurs near the line of junction of the one-inch maps 31 and 32, in western Linlithgowshire, and the adjoining parts of Stirlingshire. Most of them are within the limits of the Carboniferous Limestone series, and it is worthy of note that in Mid-Lothian there is no trace of contemporaneous igneous activity in this division of the system. It is quite possible that a larger proportion of intrusive rocks is associated with the lavas than is represented on the maps, for some of those recog- nised as intrusions are of much the same petrological type as lavas, and the lack of natural exposures often prevents the determination of the relations between the igneous and the adjoining sedimentary rocks. Various modifications of Sir Archibald Geikie’s original mapping and descriptions of the district have been made, but few are of more than local importance. The most noteworthy consists in the detec- tion of an intrusion of quartz-dolerite which traverses the hills in a north and south direction. Dr. Falconer had recognised this feature previous to the commencement of the recent revision, but his results were not made public until 1905,* by which time they had been confirmed by the independent mapping of the Geological Survey. This point will be referred to again in Chapter XV. It is interesting also to note that evidence has been obtained pointing to the conclusion that the Bo’ness lavas form a portion of the Bathgate belt, so that the latter does not end at Linlithgow as originally supposed. c. T. C. * ‘The Igneous Geology of the Bathgate and Linlithgow Hills,” Trans. Roy. Soc. Edin., 19065, vol. xli. p. 359. Volcanic Rocks from Bathgate to Cocklerue. BATHGATE TO COCKLERUE (Sheet 31 in part). * The volcanic rocks of the Bathgate Hills attain their greatest development about two or three miles south of Linlithgow. It will be convenient to take a general section from east to west along this line (see Fig. 11) as the basis of our description, and to note the changes which affect the various groups of lava and tuff, first as they are traced southwards and then as they are followed northwards. The period of vulcanicity commenced in late Calciferous Sandstone time with the accumulation over an extensive area of a bed of green and red tuff at a definite horizon a few feet above the Two-foot Coal (2, Fig. 11). From Drumcrosshall the tuff forms a well-marked band traceable almost to the shores of the Firth of Forth, a distance of over six miles, whilst its former eastward extension is proved by its occurrence in a synclinal basin of the oil-shale field at Little Ochiltree. The tuff is overlain by shales and sandstones, followed in Longmuir Planta- tion by a thin bed of green tuff and then by several flows of basalt (3, Fig. 11). The lowest of these, exposed in a small quarry on the south side of the east and west dyke, is a dark compact olivine-basalt of Dalmeny type and exhibits a well-marked columnar structure. The other outcrops show only decomposed and vesicular basalts, which dip beneath a thick series of shales and sandstones exposed in the quarry above Broomyknowes (where a thin seam of coal also occurs) and at intervals along the eastern slopes of the Riccarton Hills. They have a westerly dip of 10° to 15° and pass below the great mass of lavas, which forms the greater part of the Hills (4, Fig. 11). The individual flows, of which there are perhaps eight, may be separated in some degree by means of the little hollows formed by weathering along the line of junction of the vesi- cular top of one flow with the vesicular base of the succeeding one, and by the two intercalated beds of sandstone (5, Fig. 11). One of these lies on the north shoulder of the Hills south-west of Broomy- knowes, whilst the second occurs in small artificial exposures situated between outcrops of basalt 400 yds. south-east of Beecraigs. The lavas are all very much of one type, dark, compact olivine-basalts, but the second flow from the base is coarser-grained and more felspathic. Olivine nodules were noticed in the topmost basalt at the outcrop beside the stream about 200 yds. north-west of Beecraigs. Northwards the whole series rapidly thins out and disappears, but - to the south the thinning takes place much more Io RICCARTON HILLS TAR HILL MOCHRIES CRAIG FAULT TORPHICHEN HILLS 145 1, Houston Coal ; 2-12, see explanation in text. Fic, 11.—General Section across the Volcanic Rocks of the Bathgate Hills. 146 Carboniferous Limestone Series of Bathgate and Bo'ness District. slowly and seems to be brought about by the upper members alone dying away. The shales and sandstones at the base of the group thin out, so that, south of the Mains Burn, the Riccarton Hills and Longmuir lavas come together. Although the group is thinning away the outcrop remains broad owing to slight local folding, which results in the strike taking on an east and west direction in the neighbourhood of Quarter. The basalt situated to the north-east of Drumcross is an outlier of this zone faulted down in a shallow syncline against the tuff above the Two-foot Coal. To the southward, in Sheet 31, a bed of tuff exposed near Wester Drumecross and at Whitelaw is intercalated amongst the basalts, whilst smaller and apparently lenticular layers appear at a higher horizon in the wooded hollow east of Kirkton Lime Works. In the section in the Almond River to the south of Bathgate, the whole volcanic series of the Bathgate Hills has disappeared with the excep- tion of a bed of tuff, which is proved to lie 140 ft. above the Raeburn oil-shale, and may well be on the horizon of the Whitelaw tuff. The sediments overlying the Riccarton Hills lavas include the Tartraven Limestone (6, Fig. 11). In their southward prolongation into Sheet 31 they are largely replaced by basalt flows, marked off at the bottom and top respectively by the East and West Kirkton Limestones. H. B. M. The interesting section in the East Kirkton Quarry was first described by Dr. Fleming,* who noticed some of its more peculiar features, but it was more fully and accurately dealt with by Dr. Hibbert + and Sir A. Geikiet The latter enters into great detail, and his account is virtually followed here, but there is no important difference between the views expressed by the two authors. _ The general section in the quarry is as follows: The floor is ash resting on basalt; above this come various limestones with ashy seams intermingled, then shales and ashy sandstones, while the whole is surmounted by basalt, forming the crest of the quarry. The subjoined woodcut gives a detailed section of the north end of the quarry. The lowest bed is a loose pulverulent concretionary ash (a), rest- ing on basalt; above it comes a thin irregular band of ash-beds and ashy limestone. A very unequal stratum of limestone (c) succeeds ; at one point it measures 6 ft. in thickness, while a short way off it increases to 13 ft. It is a hard, grey, cherty rock, the chert being either arranged in fine laminz, curiously contorted, or in an irregular brecciated or nodular manner. At the present time the contorted beds are not well exposed in the quarry, but they may be studied to advantage in the walls of the neighbouring fields. The limestone is further noteworthy as having yielded several remark- able specimens of Hurypterus scouleri, named and described by Hibbert. Various alternations of ash and limestone occupy the remainder of the section (d to 7) until a mass of herbage and debris obscures the slope. Above this we again meet with a limestone (4), finely laminated, very fissile and containing remains of entomostraca ; * “ On the Neptunian Formation of Siliceous Stalactites,” Edin. Journal of Science, April 1825, p. 307. + ‘On the Fresh-Water Limestone of Burdiehouse,” Trans. Roy. Soc. Edin., 1836, vol. xiii. p. 169. t “The Geology of the Neighbourhood of Edinburgh,” Geol. Sur. Mem., 1861, p. 49. Volcanic Rocks from Bathgate to Cocklerue. 147 some of the lamine show a mammillated surface, while others have undergone great twisting and contortion. Black shales and sandy beds (/ and m), somewhat ashy in the upper part, next supervene. During the first survey numbers of beautifully preserved plants, including Lepidodendron, Stigmaria and Pecopteris, were discovered in some of these beds, but the richest fossiliferous horizon does not appear to have been found during the late revision. The following plants were, however, collected by Messrs. Kidston and Tait, and determined by Dr. Kidston—Sphenopteridium crassum L, & H. sp., Adiantites, sp.* . A bed of columnar basalt (nm) of the Dalmeny type completes the section, and, though the evidence is not conclusive, there are appearances suggesting that the base of the igneous rock trans- gresses the underlying black shales. It may, therefore, be a sill like that of the Hillhouse quarries. Both Dr. Hibbert and Sir A. Geikie referred the remark- able series of deposits underlying the basalts to the operations of geysers or thermal springs supplying a restricted lagoon, and the physical and pale- ontological features noticed above, accord well with this inter- pretation. No satis- factory explanation has, however, yet been offered regard- TeNRE ing the wemiariabls ae in Rast Quarry, Kirkton (after contemporaneous Kir A, Geinie), contortions of the laminated cherts and limestones. E, B. B Returning to Tartraven we find the shales above the limestone succeeded by a series of basaltic flows, which are exposed in sections beside the road right up to the position of the Petershill Limestone (7, Fig. 11). The lowest lava appears as a thin decomposed amygdaloidal basalt overlain by a thicker sheet exposed in quarries at Mid-Tartraven. The latter is an analcite-bearing basalt, with a well-developed horizontal platy jointing parallel to the fiuidal texture of the rock, surmounted by a weathered brecciated crust. After passing over a few crops of weathered basalt, which may indicate another flow, we reach a dark compact, columnar olivine- basalt, which extends up to the position of the Petershill Limestone. This group of lavas dies away rapidly to the north, and is represented by a bed of tuff, which is first seen near Balvormie. o *The type of Sphenopteris Hibberti, L. & H. (‘‘ Fossil Flora,” 1836, vol iii. p. 73, plate clxxvii.), also came from a “‘ deposit of fresh-water Limestone occurring at Kirkton near Bathgate.” 148 Carboniferous Limestone Series of Bathgate and Bo’ness District. Southwards the outcrop is obscured by boulder clay until the Knock is reached, when knobs of columnar basalt again appear. In this district the group is capped by a bed of tuff which lies at the base of the Petershill Limestone. The great mass of basalts that overlie the Petershill or Silvermine Limestone, lie on the whole beneath the Bathgate Coal group. In the district around Cocklerue, however, where they reach their greatest development, the coal group is replaced by lavas, which thus separate the Bathgate Coal-field from that of Bo’ness. The lowest portion consists ‘of vesicular basalts; then follow, near Craigmailing (Sheet 31), tough, black, compact, olivine basalts, sometimes with nodules of augite and usually exhibiting a well-developed columnar structure. Above these again lie three or four flows of dark blue amygdaloidal basalt, forming terraces on the hill slope. . The position of the local limestone of Wairdlaw amidst these basalts has already been pointed out (p. 111), (8, Fig. 11). Above the limestone the lavas are exposed in isolated crops of fine-grained, dark blue, columnar basalt intermingled with crops of decomposed vesicular rock, which are probably the slaggy surfaces of the different flows. Ina roadside quarry 700 yards south of Kipps the rock (a, Hillhouse basalt) contains numerous nodules of augite sometimes more than an inch long. This group of lavas may be followed southwards along the crest of the Bathgate Hills. South of the Knock the individual flows become separated by sediments, which form hollows between the lava ridges. The Bathgate Coal group having the Index Limestone at the top succeeds next to the west (9, Fig. 11). At Haddies Walls and again at Hilderston Hills outcrops of dark bluish basalt probably indicate isolated flows of basalt amongst these sediments. Above the position of the Index Limestone there follows a well- marked belt of voleanic rocks. A green basaltic tuff which lies at the base of this group, near Cocklerue, dies out to the south of Kipps. It is succeeded by a series of dark basalts, which often show a well- developed columnar jointing. It is possible, to judge from certain indications in the field, that the columnar rock of Kipps Hill is intrusive, but so far as regards the Carboniferous basalts, the possession of a hexagonal columnar jointing is so frequently a character of unquestionable lavas that it cannot, in this instance, be accepted as evidence to support the suggestion. An obviously interbedded lava possessing a vesicular and pillowy upper and under surface may have a columnar central band, a phenomenon clearly exposed over and over again in the Fife coast sections.* It is very probable that the vesicular basalts, such as those cropping out around Kipps Hill, are only slaggy surfaces of flows which are columnar in their central portions, and as the columnar rocks have the same petrographical character as the non-columnar ones, they are retained amongst the lavas. Proceeding southwards the basalts crop out again around Cathlaw House, but except for some small openings near Bishop- brae, the lavas are not again exposed at the surface. They are, ,* “The Geology of Central and Western Fife and Kinross,” Geol. Sur. Mem, 1900, p. 53 seg. Volcanic Rocks from Cocklerue to Linlithgow. 149 however, proved by the bores already quoted (p. 138) to extend southwards for some distance beyond Bathgate. The above group practically marks the close of active vuleanicity in the district. A thick bed of green tuff (10, Fig. 11), which may lie above the position of the Arden Limestone, is exposed in the wooded glen south of Lochcote Reservoir, and ashy material may be found mixed in the sandstone close up to the Leven Seat Limestone, but there seem to have been no further outpourings of basalt. The voleanic history of the Bo'ness and Bathgate Hills may be compared with that of Fife. The lavas associated with the Calciferous Sandstones and Lower Limestones of the Kinghorn district correspond to those extending from the Riccarton Hills to a position above the Wairdlaw Limestone, whilst the volcanic outbursts of the Saline Hills cover the time occupied by the accumulation of the lavas and ashes, which lie above the Index Limestone in the Bathgate Hills. H. B. M. COCKLERUE AND BROOMYKNOWES TO LINLITHGOW (Sheet 31 in part). Returning again to the base of the volcanic series to the south- east of Linlithgow, we find the tuff above the Two-foot Coal in the bank of a stream, half a mile west of Wester Ochiltree. The tuff at first sight appears coarse, containing great rounded masses, but these, when examined, are found to be calcareous concretions. The position of its outcrop northward in the direction of Haugh Burn has already been described (p. 101). G. W. G. The same bed of tuff is exposed about three miles to the north- east on the north side of the Midhope Burn at Binns Mill, where it occurs above the Two-foot Coal and not far from the volcanic vent of Binns Hill. An outlier of this tuff occurs in a faulted synclinal basin between Little Ochiltree and Three Miletown. The tuff lies above the Houston Marls and is only exposed at a few points. It is a purplish, sandy tuff with numerous black shale fragments. The dip is irregular and the underlying coal (the Two-foot) is not seen. J.8.G. W. The lavas of Longmuir Plantation are last seen in a northward direction 500 yds. south of Riccarton. They appear to be on the horizon of the Riccarton limestone bands. The farm of Broomyknowes stands at the base of another larger series of lavas, which form the main mass of the Riccarton Hills. Several flows can be made out in the stream north-west of the house, the lower ones being coarse, decomposed, and marked by small geodes lined with chalcedony, on which crystals of quartz have grown. Fresher material representing this part of the series may be got from a good exposure about 30 yds. north-west of the farm. The specimen sliced (11979) is classed by Dr. Flett under the Gallaston type. Rather finer-grained basalts appear in the stream section 300 yds. west of Broomyknowes. The basalts and fragmental rocks associated with the Lower Limestones of the Carboniferous Limestone series have at their base. a band of ash which, as already mentioned (p. 112), continues 150 Carboniferous Limestone Series of Bathgate and Bo'ness District. to the neighbourhood of Hiltly, where it is intermingled with lava flows among which it is not traceable and may die out. Farther north the flows begin to wedge out until we find only 35 ft. of “whin” in the St. Magdalene Distillery well. An horizon of igneous activity extends from the bed of whin below the position of the base of the Bo’ness and Bathgate Coal group up to the Index Limestone, which immediately overlies this group, but here and there intercalations of sediment and beds of fragmental material occur. One of the best of these can be seen in the stream W.N.W. of Preston House, where a band of fine grey ash, about 50 ft. thick, is surmounted by a few feet of shale and sandstone, upon which rests a columnar basalt lava flow, compact at the base and with indurated sandstone below for 4 or 5 inches, with a glassy appearance on fractured surfaces. These lavas occupying the position of the Bo'ness and Bathgate Coal group are usually dark compact, almost flinty rocks which hardly ever show a thick crust of decomposition products. Olivine in small phenocrysts is the only constituent visible to the unaided eye. Vesicular types are seen on the road close to the Manse south of Linlithgow, where more dolerite varieties also occur. Several specimens from different horizons were sent to Dr. Flett who finds them to be olivine basalts, chiefly of Dalmeny type, together with representatives of both Gallaston and Hillhouse types ; but these varieties are not characteristic of particular horizons. Hardly any evidence bearing on the mode of occurrence of the basalts is present, as the ground is largely obscured by drift through which only the massive parts project. The uppermost flows are seen at Woodcockdale in a stream by the canal; below the railway bridge in the Avon; and north of the road at Linlithgow Bridge. In this last locality they are succeeded by two bands of ash each about 20 ft. thick and separated by a 4-ft. parting of sandy shale with a 6-in. coal at its base; the lower bed of tuff is fine-grained and laminated, with structures like vesicles, which are lined in places with chalybite and contain white calcite at the centres. The phenomena, can perhaps be explained on the supposition that the bed flowed as a viscous mud. The upper bed of tuff contains large fragments of lava, often 5 or 6 in. across. In the bore at the Avon Mills only one band of ash is recorded with 18 ft. of sediment between it and the main mass of lavas below, but perhaps the lower bed of ash has been mistaken for sediment or even included in the “whin” below. The tuff and lavas overlying the Index Limestone position near Cocklerue appear to thin out con- siderably to the north. The comparatively thin bed seen in the Avon at the Avon Mills occurs on this horizon. According to Dr. Flett’s determination, it has the characters of a basalt of the Hillhouse type (11947). G. W. G. LINLITHGOW TO BO'NESS (Sheet 31 in part). Most of the contemporaneous igneous rocks are in the form of basaltic or doleritic lavas which are usually much decomposed, but where fresh they contain distinct blebs of olivine in many places. No general difference in character has been recognised Volcanic Rocks from Linlithgow to Bo'ness. 151 between the bands which occupy ditferent stratigraphical positions within the series. The great majority of the rock specimens which have been sliced are referred by Dr. Flett to the Gallaston type of basalts and dolerites. The lavas are mixed with subordinate bands of volcanic ash, some of which are very thick, and have probably been accumulated in the immediate neighbourhood of voleanic necks. In the northern part of the area most of the igneous rocks occur in the Bo’ness and Bathgate Coal group, wherein they form the greater part of a middle division—the thickest of the three —which separates the lower from the upper coal-bearing beds, as already described. Farther south, however, it is clear, from various small rock exposures on the north side of Linlithgow Loch and from the evidence afforded by a considerable number of borings, that the igneous rocks are in excess of the sedi- mentary in the lower division of the Coal group, and are also greatly developed in the upper part of the Lower Limestone group. Near the Forth the lowest igneous rock of which we have any certain knowledge is a thin volcanic ash, 5 ft. thick, interstratified with a thin limestone in a boring near No. 9 Pit, Grange. This limestone is hidden at the outcrop by superficial deposits, but in the bore its top is 16 ft. below the base of the Carriden Lower Limestone. Not far above the last-mentioned tuff is a much thicker ash bed, well seen at the back of the 25-ft. raised beach near Carriden House. It occupies nearly all the interval, amounting to 50 or 60 ft. perhaps, between the Carriden Lower and Middle Limestones. It is generally well stratified, mainly composed of pieces of de- composed basic igneous rock less than half an inch long, and dips at gentle angles in the same direction, generally south or south- east, as the adjoining sediments. Some of the bands are mingled with shaly or sandy material, and the top is overlain by the Carriden Middle Limestone, which is itself mixed with some ashy material. It appears to thin out rapidly towards the west, for it is stated that the boring (made by chisel) about 100 yds. west of Carriden Church—less than half a mile from the ash out- crop—pierced no tuff, though it reached the Carriden Lower Lime- stone. In the journal of a boring near Springfield the top rock, for more than 11 fms. below the drift, is recorded as fakes and fireclay, underlain by a thin impure limestone—the first of a series of three which occur near together. It seems probable that this limestone represents the Carriden Lower Limestone, and that the overlying rock is in reality volcanic ash, and a continuation of the Carriden bed. Near Upper Bonnytoun another boring, about half a mile west of that at Springfield, pierced more than 21 fms. of whin, with more than 16 fms. of: rock beneath, whieh is described partly as faky fireclay and partly as fakes and fireclay. It seems probable that this lower rock may also represent the Carriden ash, or a neck from which this tuff was derived. It is to be noted that it is underlain, not by limestones and sedimentary strata, like the 152 Carboniferous Limestone Series of Bathgate and Bo’ness District. supposed ash at Springfield, but by lower beds of whin mixed with rocks called fireclay and fakes or faky fireclay.* The boring was continued to a depth of 85 fms. beneath the drift, and with the exception of 17 in. of hard sandstone the journal records no rock except whinstone, fakes and fireclay or faky fireclay, and it is certain that all these must be below the horizon of the Smithy Coal, which was formerly worked.on considerably higher ground about half a mile to the north. Various types of basic igneous rock, some of them with distinct olivine, and others extremely vesicular and decomposed, crop out near Walton in a rocky bank striking nearly east and west. The bank faces south and perhaps lies near the northern side of a fault—possibly a continuation of that which crosses .the volcanic rocks a mile farther west with a considerable downthrow to the north. These rocks were formerly mapped as parts of a broad east and west dyke, but none of them are quartz dolerites, and two (808, 11758) are referred by Dr. Flett to the Gallaston type of dolerites. Their stratigraphical position is doubtful, but they probably lie between the Smithy Coal and the Carriden ash—considerably below the level of any of the lavas that are known farther north-east near the shore of the Forth. At the old mine north of Upper Bonnytoun, whinstone is said to occur almost immediately below the Smithy Coal, and a third of a mile south-west of Upper Bonnytoun a basic vesicular rock is exposed, probably on a slightly lower horizon. In the northern part of the area, the middle division of the Coal group, consisting largely of volcanic rocks, comes between the Red Coal and the seam of the Upper Parrot and Ironstone. This division generally exceeds 500 ft. in thickness, and more than half of it is usually composed of igneous rocks—all apparently in the form of lava flows except one thin band of ash, which was formerly observed by Mr. Cadell at the base of the division, just under the lava that crops out about half a mile E.S.E. of Bo'ness Railway Station. Owing to the scarcity of exposures it is impossible to trace the different flows far in the field, nor is the plane between two consecutive flows usually recognised underground unless it is accompanied by some layer of sediment. It seems probable, however, that the average thickness of individual flows is not great, for thin streaks of altered sediment are often found within them either steeply inclined or at low angles. In some cases these streaks have probably been formed near the upper surfaces of flows, in cracks produced shortly after the solidification of the lava, but in others they may have been rolled along with the lava while it was still in a state of flow. The bottom lava which comes above the Red Coal is well seen in the following localities: in the southern suburbs of Bo’ness where it forms a series of small scars striking slightly north of west; on the eastern side of the hill+ with the monument, situated 1167 yds. north-west of Upper Bonnytoun; and in two places, near the * H. M. Cadell in his “‘ Notes on the Volcanic Rocks of Borrowstounness,” T'rans. Edin. Geol. Soc., vol. iii. p. 304, regards all the rocks in this boring as volcanic ash. The distinctions made in the bore journal are unsatisfactory, particularly as some of the whin is described as soft and light. He states that the borer identified a piece of decomposed Carriden ash with some of the rock bored. + Usually called Bonnytoun Hill, but not named on the one-inch map. Volcanic Rocks from Linlithgow to Bo'ness. 153 shore, on the north side of the big east and west fault with down- throw to the north, which passes about half a mile south of the seaward end of Bridgeness Pier.* This bottom bed is only 2 ft. thick in a boring near the north-east corner of the Bridgeness workings,t but in No. 6 Pit, Grange, it is 8 ft., while in No. 18 Pit, Kinneil (Lothians Pit), it is reported to be 59 ft. thus showing a rapid increase towards the west: It seems possible, however, that the thick band last mentioned may include two or more flows which come together without any sedimentary parting. In the Snab Pit the position of the Red Coal seems doubtful: if the 6-in. coal at a depth of 902 ft. represents it, then the overlying igneous rock, without any sedimentary parting, is in this locality as much as 91 ft. thick, which would show a still further increase in thickness in a westerly direction. But if Mr. Cadell is correct in regarding this 6-in. seam as the Wandering Coal, the bottom lava which lies above the Red Coal must have died out in a westerly direction between the No. 18 Pit and the Snab. The vesicular bottom of the lava on the east side of Bonnytoun Hill is well exposed at the mouth of an old day-level nearly half a mile N.N.W. of Upper Bonnytoun. Part of it is not more than 5 in. above the top of the coal, but does not seem to have produced any appreciable alteration therein. It shows a “pillow structure,” being divided into large rounded vesicular masses, 2 or 3 ft. in diameter, some of which are to a large extent, if not entirely, isolated from one another by partings of clay shale. In a vertical face of the trap mass which comes above the Red Coal about 300 yds. 8.S.W. of the seaward end of Bridgeness Pier, a parting of dark micaceous sandstone, about 5 in. thick, appears to include pieces of trap and to descend in places in thin strings into the underlying rock. In a quarry a quarter of a mile north-west of North Bank three bands of basic igneous rock are sccn, of which the lower, lying above the sediments which include the Wester Main Coal, is about 30 ft. thick. The middle band is 18 or 20 ft. thick, and the top of the upper is not exposed. Between the lower and the middle band there is in one place, but not generally, a parting of sediment, about a foot thick, and several round lumps of vesicular trap which appear in vertical section to be entirely surrounded by sediment.{ The parting of sediment which separates the middle and the upper bands is only 2 or 3 in. thick. Specimens from both of these partings (11751 from the upper and 11752 from the lower) have been ex- amined under the microscope by Dr. Flett, and are stated by him to show considerable alteration. The polished face of 11752 shows very well the irregularities of the igneous surface on which the sediment lies, and which frequently forms little projections, facing in one direction, which may possibly indicate overfolds in the original flowing surface of a lava. The higher layers of sediment *It was in the western exposure that the remains of the lycopod stem, described by H. M. Cadell (“The Occurrence of Plant Remains in Olivine Basalt in the Bo’ness Coal-Field,” Trans. Edin. Geol. Soc., vol. vi. p. 191), were found. +H. M. Cadell, “The Carboniferous Limestone Coal-Fields of West Lothian,” Trans. Inst. Min. Eng., vol. xxii. 1901, p. 383. t Since this description was written the quarry has been extended, and a somewhat different section exposed. 154 Carboniferous Limestone Series of Bathgate and Bo'ness District. in the little hollows of the trap sometimes overlap the lower, and abut against the sides of the hollows. A few pieces of igneous rock seem to be isolated in the sediment, but the top surface of the main mass of lava is, through all its irregularities, much finer than the interior, and can in this locality have suffered little or no denudation. It seems indeed possible that it was hot and perhaps still flowing at the time the sediment was laid down on it. In another quarry, two-thirds of a mile N.N.E. of Gardeners Hall, two bands occur, which are probably in a somewhat higher strati- graphical position but still below the Upper Ironstone: in the upper band, which is very vesicular, we find various streaks of siliceous material, sometimes 4 or 5 in. thick, which cross the igneous rock at various angles, sometimes steeply. They are much more siliceous than any common type of sediment found in the district, and are described by Dr. Flett as cherts (11753, 11754, 11755, 11786). They show no radiolaria or other traces of organic remains, but include pieces of extremely decomposed basalt or dolerite. Specimen 11786 was found by Dr. Pollard to contain 91:83 per cent. of silica. In a quarry (at Bell’s Knowe) nearly a quarter of a mile S.S.E. of Bo’ness Railway Station two lava flows are seen in about the same stratigraphical position as the bands in the quarry last mentioned. The lower flow is 40 ft. thick and separated from the upper by a thin layer of sediment, averaging about a foot thick, composed of micaceous shale, indurated sandstone and an impure coal, which, Mr. Cadell states,* has been crumpled and at one place completely doubled up by the overlying flow. The decomposed top of the lava under the coal is traversed by various calcareous streaks, one of which (11787) appears to Dr. Flett to have been marmorised along a thin layer at the contact. Many loose blocks on the waste heap of No. 3 Pit, Kinneil, show an impure sandy sediment wrapping round large pieces of vesicular trap, which have perhaps come from near the horizon of the Wandering Coal (see p. 132). In the southern part of the area many bands of igneous rock have been found in positions below the Red Coal, and the sedimentary partings are subordinate to them. These, however, are not well exposed at the outcrop, and it is doubtful where they first come in. In the boring No. 2 Bonnytoun (Kinneil), which is near the old mine near Upper Bonnytoun, the journal records one band between the Six-foot Coal and the East Main and another between the East Main and the Smithy. Farther south-east the borings No. 2 and No. 1 Parkhead show an excess of whinstone for several hundred feet below the probable position of the Red Coal. Near the Forth the volcanic rocks that underlie the Upper Ironstone are succeeded by a series of sediments, about 270 ft. in thickness. The next volcanic zone is not far beneath the Index Lime- stone where an olivine dolerite of Dalmeny type (11772) occurs, which is well exposed at Bo’ness Distillery, its thickness there being about 24 ft., and its top 10 ft. below the limestone. Mr. Cadell states that a thin bed of ash was formerly exposed just beneath the lava in this locality. Both westward and southward from the distillery this * “ Notes on the Volcanic Rocks of the Borrowstounness Coal-Field,” Trans. Edin. Geol. Soc., vol. iii. p. 311. Volcanic Rocks from Linlithgow to Bo'ness. 155 volcanic zone increases considerably in thickness, being 51 ft. in the Snab Pit No. 1, and about the same in No. 3 Pit, Kinneil.* Farther south, near the Avon and the Little Mill, the section below the Index Limestone is very different and shows more igneous rock. Fifty yards above the foot of the burn that comes inte the Avon from the north nearly a third of a mile north-west of the Mill, the coal below the Index rests directly on a fine-grained, reddish- brown mudstone, 18 or 20 ft. thick, which contains in places round lumps of dark igneous rock about a foot long. The top of the mudstone is penetrated by many narrow cylindrical harder parts, which perhaps represent fossil rootlets. Underneath it come 9 or 10 feet of shaly or flaggy sandstone underlain by tuff—the top of the Little Mill ash, which is so well exposed in the big scars on the river side between this locality and the Little Mill. It is generally of a dark-green colour, false-bedded and full of fragments of decomposed vesicular trap, often about half an inch long, together with other much larger and fresher pieces. The larger occasionally attain a length of several feet, are somewhat round and perhaps represent “bombs.” Mr. Cadell states that the bed contains pseudomorphs of splinters of coniferous wood, in which the woody substance has generally been entirely replaced by calcareous matter.+ The dip is usually at gentle angles, rarely as much as 25°, and near the Little Burn it is in the same direction and of much the same amount as that of the overlying sediments. In the burn 5.8.W. of Swordie Mains, however, the ash dips nearly south at gentle angles, though it is almost certain that the underlying sedi- ments on the south-east side must have a westerly inclination. The appearances may be best accounted for on the supposition that the beds of ash were originally piled up so as to form a bank with the layers on either side inclined outwards at angles of 20° or 30°. A series of borings (Balderston borings) just on the north side of the scars of tuff in the Avon have pierced considerable thicknesses of sediment mixed with rock, recorded as “ whin,” presumably ash in these cases. Hence it is clear that the ash must be of very irregular distribution. Perhaps it lies very near a submarine volcanic neck (of earlier date than the Index Limestone) and from time to time the materials may have been irregularly sorted under water. The boring No. 6 Kinneil (see p. 136) begins in the tuff about 150 yds. east of the Mill, and goes down 490 ft. before meeting the first band of sediments, which consists of blaes and faky fireclay about seven feet thick. Mr. Cadell supposes this boring has pierced the voleanic neck which supplied the ash,t but the bedding in the tuff only 30 yds. away is almost horizontal, and at various depths below the sediments described other thin bands of blaes are recorded, down to the bottom at 691 ft. In the burn a third of a mile north-west of the Mill a band of decomposed dolerite (11771) occurs a little above the top of the tuff. This must be nearly on the same stratigraphical position as the trap at Bo'ness Distillery, but possibly it is of intrusive character. About 230 yds. N.N.E. of the Snab Pits a band of olivine dolerite (11773), probably a lava flow, is exposed at the roadside and was * H. M. Cadell, op. cit., plate facing p. 312. f Op. cit., p. 313. | Op. cit., p. 318. 156 Carboniferous Limestone Series of Bathgate and Bo'ness District. formerly visible on the foreshore a little farther north-west. Thé stratigraphical position seems about 150 ft. above the Index Lime- stone, for Snab Pit No. 1 pierced a band of “ whinstone,” 5 ft. 6 in. thick, in this position, very near the top of the shaft. In the Avon near the Avon Mills east of Waukmilton, and in the water- course north of the mill, a band of much decomposed porphyritic olivine basalt (11774) occurs, and in boring No. 1 Langloan, about 200 yds. west of Kinneil Mills, this band was again found, with a thickness of 22 ft., and its base about 90 ft. above the Index Limestone. As the sedimentary beds above this limestone seem to become thicker northwards to the Forth (see p. 141), it is possible that the band is the same as that exposed near the Snab Pits, especially as it appears to have been met in several bores a little north of the Avon, including No. 2 Russell, in which the base was 110 ft. above the Index Limestone. About 300 yds. west of the Snab Pits a slightly higher band of “greenstone” was also formerly exposed on the foreshore, but is now deeply covered under artificially made ground. The top of an ash bed is obscurely seen in a little burn about 170 yds. N.N.E. of Kinneil Mills: its stratigraphical position is possibly 40 or 50 ft. below the Kinneil Mills Limestone; the thickness is perhaps only a few feet. About 11 ft. below the outcrop of the Kinneil Mills Limestone in the Avon a thin oolitic, calcareous, ferruginous bed contains green chloritic patches (11746), which Dr. Flett supposes may possibly represent pieces of decomposed ash. In a still higher position, perhaps nearly half-way between the Arden (Dykeneuk) and Castlecary (Leven Seat) Limestones, we find two other thin oolitic, calcareous, and ferruginous beds, the lower of which (11748) contains lumps stated by Dr. Flett to have some resemblance to volcanic spongy lapilli. C.T. 6, In the neighbourhood of Charlestown on the north side of the Forth, the volcanic group of the Bathgate Hills is represented only by some thin beds of tuff interstratified with the Lower Limestone group. A bed of coarse tuff overlies a limestone in the railway cutting three-quarters of a mile west of Charlestown Station, and several beds of green tuff are interstratified with sandstone in the middle of Ironmill Bay. A broad exposure of greenish tuff, near low-water mark in the middle of the Bay, may mark the site of an ash-neck, the sedimentary rocks close to the tuff being tilted up at high angles. H.B. M. VoucANic NecKS WEST OF EDINBURGH AND THE PENTLAND HILLs. In the upper Oil-shale group and basal beds of the Carboniferous Limestone series masses of agglomerate and tuff occur, sometimes pierced by irregular intrusions of basalt. In some cases these necks form prominent features in the landscape; in others they are known only through underground mining operations. Very interesting in this respect is the neck at Gallowscrook, near Philpstoun, described below. is ; ; Beyond the fact that the necks must be later than the sediments Volcanic Necks West of Edinburgh. 157 through which they cut, there is no direct evidence as to their age, but it will be noticed from the map that these necks all lie to the eastward of the lavas and tuffs of the Bathgate Hills, and pierce rocks, which lie below or at the base of the extrusive rocks. There can therefore be little doubt that the necks mark some of the orifices through which the Bathgate Hills volcanic series were erupted. The petrographical similarity of the tuffs and basalts occupying the necks with the bedded tuffs and lavas further strengthens this view. U.B.M, The ground plan of the neck at Niddry Castle forms an irregular oval, the longest axis measuring 500 yds. It is filled with a fine- grained, dull green tuff which in places contains small fragments of black shale and grains of carbonate of copper. The ash is unstratified and in places contains large fragments of shale and ironstone. Two intrusions of dolerite intersect the western side of the neck, and on its north and south sides the surrounding strata roll over and are inclined towards the vent. The Tar Hill vent lies directly north of Ecclesmachan village, and forms a conspicuous feature in the landscape with the deep hollow of the Niddry Burn encircling its southern and western sides, while the eastern flank is a long sloping drum of boulder clay. Its longer axis measures 700 yds. The rock is a fine-grained, unstratified tuff with many baked fragments of shale. Two small orifices occur at West Broadlaw and south of West Binny, which are filled with dull yellowish and green tuff with small indurated fragments of shale and sandstone. The neck at Gallowscrook half a mile east of Philpstoun does not appear at the surface, but was found during mining operations in the Broxburn Seam at this locality. A mine, 360 ft. in length, crossed the vent, and the walls were found to be quite perpendicular but somewhat slickensided, doubtless due to the subsidence of the materials. The oil-shale was unaltered to within a foot or two of the ash, and in common with most necks the strata for some little distance dip towards the vent. The tuff varies in character and structure, is chiefly fine-grained with occasional large blocks of black shale or, again, it contained small veins of pitch or solid paraffin.* If the extent of ground covered by tuff round any one neck forms any criterion as to the actual size of the vent, that of Binns Hill would then be the largest in this district. It is quite possible, how- ever, that the actual neck is smaller than the area shown on the map and that a portion of the ash-covered ground includes material heaped up outside the margin of the vent. One small exposure of tuff in a quarry and another in a small cliff below probably indicate the presence of a small neck at West Shore Wood. The green agglomerate contains rounded and angular bombs up to one foot in diameter. Blocks of dark greenish grey tuff probably mark the position of a small neck on the shore a short distance to the east of Society. J.8.G. W. A small voleanic neck, filled with coarse agglomerate, is exposed in the Brox Burn below the filter beds for the Bangour Asylum Reservoir. The agglomerate, in contrast with the bedded tuff *H, M. Cadell, rans, Inst. Min. Hing., 1901, vol. xxii. p, 353, 158 Carboniferous Limestone Series of Bathgate and Bo’ness District. exposed higher up the burn, contains abundant large blocks of agglomerate and of sedimentary rocks. It truncates the edges of the surrounding shales and sandstones, which are greatly disturbed. The conical hill of tuff that forms the summit of the Riccarton Hills may be a neck, but the relations with the surrounding basalts are obscure. H. B. M. In the Calciferous Sandstone and basal beds of the Carboniferous Limestone series, in the neighbourhood of Linlithgow, masses of coarse agglomerate occur, sometimes forming prominent features, as at Pilgrims Hill north of the Poorhouse, east of Cauldhame and east of Parkly Place. The lapilli are sometimes an inch across, but usually smaller. They are composed chiefly of igneous material, but carbon- ised plant fragments are common. The microscope shows that sand grains form a considerable part of the finer material between the larger fragments. Basalt intrusions, in the form of plugs or thin dykes, are frequently connected with these masses of ash, and are com- posed of rock similar in appearance to that of the lavas, but a specimen from one of the plugs 700 yds. north of Riccarton was found on microscopic examination by Dr. Flett to contain analcime. The adventitious appearance of the masses of ash referred to, their oval or circular plan, their massive character, unbedded appear- ance, and their intimate association with intrusive rocks similar to the lavas, support the conclusion that these masses represent filled- up vents whence the lavas in the overlying strata have been poured out. G. W. G. CHAPTER X. CALCIFEROUS SANDSTONE SERIES OF THE MID-LOTHIAN BASIN. Tue Mid-Lothian Coal-field lies, as already stated, on the eastern side of a line of powerful disturbance—the Pentland fault—trending N.N.E., which has brought up the older Paleozoic Rocks of the Pentland Hills on the west (see horizontal section in Sheet 32, colour printed edition). Within this coal-field an important development of true Coal Measures forms a basin, the axis of which is nearly parallel to the fault. It seems probable that the synclinal arrangement of the strata has been developed under the influence of considerable earth pressure acting from a westerly direction, for on the west side of the basin the rocks often dip at high angles, from 50° to 90°, or are even reversed, while on the east the inclination does not usually exceed 25° or 30°. The strata are divisible into various groups, the positions and general thicknesses of which are shown in the following table :— Middle Coal Measures (?), perhaps 460 ft. Upper Lower Coal Measures, perhaps 1300 ft. Carboniferous. Millstone Grit or Roslin Sandstone Series, upper portion, often about 400 ft. Millstone Grit or Roslin Sandstone Series, lower portion, often about 200 ft. Carb. pee Limestone Group, from 550 to 1070 ft. ‘Caner Limestone ; Edge Coal Group, from 550 to 1000 ft. Caxieniteveia. Series. Lower Limestone Group, from 240 to 540 ft. Sandatoné but probably diminishes greatly southwards Baries and eastwards. alotternas | a Group, more than 2000 ft. at Straiton, Cementstone Group. The detailed examination of the Mid-Lothian basin has proved that in the north-west portion of the area, in the neighbourhood of Niddrie, the strata are unusually thick, while both in a south- western and an eastern direction from that locality all the groups diminish in thickness, and the coals of the Edge Coal series become fewer and thinner.* The only exceptions are some of the limestones. Between Niddrie and the Emily Pit, Arniston—a distance of about six and a half miles in a S.S.E. direction—the Edge Coal group thins down from about 1050 ft. to about 600 ft, and there is a strong presumption that the diminution continues still farther in a southerly direction from the Emily Pit. At Mauricewood, near Penicuik, the decrease is also marked, the thickness of strata between the top of the highest and the bottom of the lowest coal in this division being only slightly more than 500 ft. (see p. 211). At * Most of these points have been illustrated in the vertical sections engraved on the margin of the colour printed edition of the one-inch map 22, 159 160 The Mid-Lothian Basin. the same place the total thickness of the coal seams in the group referred to is diminished to 44 ft. while at Loanhead—hardly four miles away—it is 97 ft. In the Lower Limestone division the diminution in thickness from Gilmerton to Middleton and Esperston is equally pronounced, from about 700 ft. to about 200 ft. It will also be seen from the vertical sections in Sheet 32 that the Lower Coal Measures and the Edge Coal group include a valuable series of coals, and are separated from each other by a somewhat barren division composed of the Roslin Sandstone series (Millstone Grit) and the Upper Limestone group. Some coals of good quality are found in certain districts among both the Upper and the Lower Limestones, and thin impure limestones and marine horizons are known to occur in the Coal Measures, and also in the Roslin Sandstone series and Edge Coal group. It is noticeable in this district, as in many others, that the limestones and marine horizons often lie only a little distance above coals and fireclays. The length of the basin formed by the true Coal Measures, from the sea at Musselburgh to the southern extremity beyond Rosewell, is rather more than nine miles. Its breadth varies considerably from place to place, chiefly in consequence of cross faults, but it probably never exceeds three and a half miles. Round the central basin of Coal Measures the Roslin Sandstone series forms a belt which is particularly narrow in the north- west area in consequence of the unusually steep inclination of the strata. It also extends for a considerable distance in a south- westerly direction past Penicuik to Auchencorth Moss, near the southern margin of the map. Outside the rim formed by the Roslin Sandstone the different divisions of the Carboniferous Limestone series are affected by various folds. Thus on the west, near Gilmerton, a compound syncline causes the outcrop of the Carboniferous Limestone series to extend locally nearly three-quarters of a mile west of its usual line of crop. A little farther south near Broomhills and Bilston Burn, the Gilmerton syncline may still be recognised lying to the west of the Straiton anticline (see Fig. 13, p. 163). It will be observed that at the west side of this section the beds are reversed near the Pentland fault, as is often the case in other places situated along this belt of disturbance. On the east side of the basin there is one important anticlinal fold with a N.N.E. axis, along the centre of which beds belonging to the Lower Limestone group emerge at Cousland and the Roman Camp. On the eastern side of this anticline the Edge Coals dip E.S.E. and extend eastwards into the East Lothian Coal-field (see ‘The Geology of East Lothian,” 1910, Geol. Sur. Mem.). The strata on the south-western side of the Musselburgh and Rosewell basin of Coal Measures are affected by various folds, some of which appear to die out before they reach the basin, and along the synclinal portions of these folds we find various small outliers of Coal Measures, one just south of Penicuik and another a mile and a half 8.8.W. of that town. In this district the Calciferous Sandstone series is chiefly confined to the western side of the basin, but it occurs also to the south-east of the Lower Limestone group near Borthwick and Calciferous Sandstone Series. 161 Old Middleton. As will be noticed subsequently, it includes some beds of marine limestone of much the same type as those in the Carboniferous Limestone series. The boundary line between the Calciferous Sandstone and the Carboniferous Limestone series has been drawn at the base of the Gilmerton Limestone, which, in the Bilston Burn, has been converted into ochre. But a considerable amount of stratigraphical and paleontological evidence has been accumulated, partly by Mr. Macconochie, which makes it not improbable that a lower limestone, the base of which in the Burdiehouse Burn lies 130 ft. below the Gilmerton Limestone, really corresponds to the Lower Longcraig Limestone of Dunbar, which, in that locality, is taken as the base of the Carboniferous Limestone series. The little limestone referred to rests directly on a calcareous shale with abundant remains of Rhipidomella [Orthis], underlain by a thin pyritous shale, a few inches thick, with fish remains and Lingula. A shale with Schizo- phoria and Rhipidomella and a similar fish bed occur below the Lower Abden Limestone on the coast of Fife, which in all probability corresponds in position with the Lower Longcraig of Dunbar, though neither the shale nor the fish bed has there been found in connection with it. The chief dislocations affecting the coal-field strike approxi- mately east and west, and have a downthrow to the north, as, for example, the Sheriffhall fault—which passes through Dalkeith— and the westerly continuation of the large north-east fault at Vogrie. The displacements effected by both these faults appear to be very large near the centre of the basin, but much less at the sides, and this fact has led to the supposition that they were developed in great part simultaneously with the folding that produced the synclinal arrangement of the strata. One of the best sections in the district is that on the shore at Joppa, which extends from about the middle of the Upper Limestone group, through the Roslin Sandstone series, into the Lower Coal Measures. It has been measured by W. Gibson and D. Tait, and the details are shown in the horizontal section (Plate VII.), but it should be stated that the coal seams are not well seen, and the positions of some of them are doubtful. Probably the best inland section of the Carboniferous strata is that in the Bilston Burn, on the west side of the basin, near Loanhead, which cuts the lower part of the Roslin Sandstone series, the whole of the Carboniferous Limestone and part of the Calciferous Sandstone (see Fig. 15, p. 181). The lower beds of the true Coal Measures are well exposed in the North Esk near Elginhaugh, in the South Esk near Newbattle Abbey and in the railway cutting near Broomieknowe Station. Crt.C, OIL-SHALE GROUP. PORTOBELLO, NIDDRIE, AND GILMERTON AREA. Certain oil-shales to the west of Niddrie have been artificially exposed, but they have never been wrought, and the record of the precise position of their outcrops has been lost. We have no exact II 162 The Mid-Lothian Basin. knowledge of even the upper portion of the Calciferous Sandstone group north of Gilmerton, but near this village the Burdiehouse Burn twice in its course affords a good section of strata underlying the Gilmerton Limestone. At Hyvots Bank, just above the first crossing of the limestone by the stream, the section is more extensive, though not so clear as that exposed farther down stream, for a short distance above the bridge of the main road. The Hyvots Bank section has, moreover, the advantage of showing the beds in question passing naturally beneath the Gilmerton Limestone, while in the other section a small fault obscures the relationship. The two sections agree in their details, which are shown below, in descending order, as far as the down-stream section extends. Ft. GILMERTON LIMESTONE, Black Shale (middle portion burns) .. 10 LIMESTONE, almost entirely consisting of remains of Productus semireticulatus and P. lonqispinus. . Coat of poor quality Fireclay ‘ Sandstone ; Dark Fireclay .. Ironstone band with plants and fish remains Dark Shale * : Coal daugh Flaggy Sandstone Sandy Shale Black Carbonaceous Shale LIMESTONE, dark Black Shale Black Shale Saal 3 rb WWOMDD TD DH WO Tb bo oooococooooo°o°o0°o CoH, _ _ The Hyvots Bank section shows some still lower beds, namely—. i>] + al 3 ee COWwWoor: LIMESTONE, dark Dark calcareous Shales with LIMESTONE nodules. LIMESTONE, dark shaly .. LIMESTONE, massive grey encrinital, with Phipidomella band at base Thin band with Lnngula and fish bones ae bed a Dark Shale : Grey Shale with ironstone nodules CoaL, Parrot... Grey Shale (passing down into faky sandstones) at least IOOR CMooOwocoocdod Where the grey shale at the bottom of the above section is reached in the burn, a fault reintroduces the lower part of the limestone and the bone bed.t The Parrot Coal in this second exposure is overlain by a 2-in. blackband ironstone with remains of entomostraca. The sandstones beneath the grey shales are not well seen; they are thin, however, and in the second exposure are underlain by grey marls with calcareous concretions. Below these marls there is a gap in the section, but from com- parison with the fuller sequence of the Bilston Burn section, to be described in the sequel, it is probable that these grey marls rest upon “In this section “Shale” does not imply oil-shale as inthe Diamond Bore Section on p. 164. { This bone bed, both here and in Bilston Burn, was first discovered by “Mr. Macconochie. Calciferous Sandstone between Straiton and Glencorse Burn. 163 a considerable mass of grey faky sandstone, part of which is cut out by the continuation of the fault which, as already mentioned, redupli- cates a portion of the section farther down stream. Be this as it may, the next beds below the faky sandstones of Bilston Burn are exposed in the Burdiehouse Burn a little below the Lasswade road, and consist of a mass of grey sandy shales overlying a thin grey shaly marine limestone—the Cephalopod Limestone of Bilston Burn. It should be mentioned that a coal, reputed to be about two feet thick, was wrought in Bilston Burn at a slightly higher horizon than these grey shales, and although not actually exposed in Burdiehouse Burn it would probably be easy to locate the outcrop. It is interesting to recall that Mr. John Henderson was the first to draw attention to the occurrence of marine limestones below the Gilmerton Limestone in this burn section.* The relations of these marine bands to the Lower Abden Limestone in Fife will be referred to in the sequel (p. 170). E. B. B, AREA BETWEEN STRAITON AND GLENCORSE BURN. No representatives of the Cementstone group have been detected in this area, but the tract is one of economic importance from the presence of a succession of valuable oil-shales overlying the Burdie- NE SM BROOMHILL STRAITON LOANHEAD o 500 1000 2000 FEET /A\MOND BORE ~ \ \ \ if > EDGE COALS ETC. OF LOANHEAD FIELD N XN mn e \ \ \ \ } Vis {G oN A) Ser ae Lf Bo 44 “ yet \ ae, 7 \ ia Be N > X Fic. 18.—Section of Burdichouse and Straiton Shale-field. P.S. Pumpherston Shale. B.L. Burdiehouse Limestone. D.S. Dunnet Shale. By.Sa. Binny Sandstone. B.S. Broxburn Shale. F.S. Fell Shale. H.C. Houston Coal. Pa.S. Paper Shale, N.G.L. North Greens Limestone. P.F. Pentland Fault. house Limestone at Straiton, which represent some of the well-known seams in West Lothian. Much information regarding the succession of the oil-bearing strata is available from mining records, which can be supplemented as regards the higher portion of the Oil-shale group by the excellent natural section of Bilston Burn. The. main structural features may thus be briefly summarised. * Qn some Marine Beds underlying the Gilmerton Limestone,” Trans, Edin. Geol. Soc., 1882, vol. iv. p. 217. 164 The Mid-Lothian Basin. A well-marked anticlinal fold runs in a N.N.E. direction near Straiton, on whose western side the beds form a compound syncline, the western limb being inverted next the Pentland fault. The latter fold is a continuation southwards of the Gilmerton trough. On the eastern side the members of the Oil-shale group plunge beneath the Carboniferous Limestone series at high angles. In the southern portion of the mined area, near Pentland Mains, the three seams are thrown into a sharp compound anticline, and after passing over this flexure the different outcrops, without any break, resume their former trend. The most important geological horizon in this area is the Burdie- house Limestone which has been wrought only on the east side of the Straiton arch, but its position to the west has been proved in bores. To the north its outcrop is truncated by a fault with a down- throw of 60 fms. in that direction, which crosses the Straiton anticline with an east and west trend and is probably the continua- tion of the Sheriffhall dislocation. Definite information concerning the nature of the strata below the Burdiehouse Limestone is afforded by a diamond bore at Straiton which was put down in the centre of the anticline (Fig. 13). It begins a short distance below the limestone and its general features are given in the following section :— Diamond Bore, Straiton (condensed). Ft. In. Surface... a or sis a .. 69 6 Blaes a a oH oe pe .. 38 0 LIMESTONE (fossils) .. ai si i . 1 9 Fakes and Blaes .. 3 iS a s« 9 & Sandstone .. i a8 ie me . 4 6 Fakes and Blaes .. sin sad sie . 49 5 Sandstone, brown oe i a . 45 4 Fakes and Blaes .. i i i .- 70 2 Shaly Blaes .. ie ag on &% war, Abd FO Blaes and Fakes .. bis oe: ss . 4 41 Sandstone, limy posts .. 26 si - 14 7 LIMESTONE (fossils) .. ie si ie we Lt) 0 Blaesand ribs... 9 as se we U1, 2 Coan. Zi 3 - O 1 Fakes and Fireclay on top ee oe .. 25 11 Sandstone .. 3 ae w 31 7 Blaes, Fakes and ribs as 2 oe .. 385 O LIMESTONE (fossils) .. is 0 oe « 0 8 Faky Blaes and ribs isd i iv .. 387 0 Shale .. od ie ak . O 4 Oil-Shales at Limy Fakes and Blaes .. vy ais .. 64 0 Pumpherston { Shaly Blaes with rib .. 5% sr at . 5 0 position. Sandstone and Blaes .. re ais ce 0 2 Shaly Blaes .. is die 6.3 . ll 5 Blaes with cement ribs .. as fe .. 380 10 Sandstone with partings. . Bs 8 = 8 Blaes with cement ribs .. re aa .. 32 4 Sandstone with partings.. ws a » 438° 5 Blaes ne es Sa .. 51 8 Marls, Blaes with ‘cement ribs .. Bx .. 27 10 Faky Blaes and ribs ee ais oe se BT 8380 2 Calctferous Sandstone between Straiton and Glencorse Burn. 165 The shale and shaly blaes lying between 460 and 548 ft. from the top apparently represent the Pumpherston position. To the east of Crawley Cottages in Glencorse Burn, a 4-in. coal and thin limestone band with blaes are seen in the bed of the stream. A gap equivalent to 100 ft. of strata here occurs, beyond which comes a thick brown sandstone dipping again to the east. This thin coal may possibly be the equivalent of the 1-in. seam in the Straiton bore, and the sandstone may represent the brown sandstone, 45 ft. thick, which lies 112 ft. above this coal. : Higher up the stream the following section is exposed :— Ft. Black blaes with cement bands oe i 2% .. 8 Grey blaes and fireclay .. ae aye si aa .. 10 Sandstone, banded .. oy ke = a6 of . 4 Burdichouse Limestone.—Reference has already been made in Chapter VI. (p. 47) to Dr. Hibbert’s classic paper on the limestone at Burdiehouse, in which he called attention to the absence of true marine organisms and advocated its fresh-water origin from ‘the occurrence in it of plants, entomostraca and fish remains chiefly of Paleoniscid fishes. After a prolonged study of Scottish Carboniferous ichthyology, Dr. Traquair has been led to the conclusion that the distinctive fish fauna of the Burdiehouse Limestone implies estuarine as opposed to marine or open sea conditions. The fish remains are frequently found, though not in the Burdiehouse Limestone itself, in association with Zingula but not with the hinged brachiopods, such as Productus. In the previous edition of this memoir, Salter remarked * that “the fossils found in the Burdiehouse Limestones are for the greater part distinct from those of other parts of the Lower Carboniferous series. This may be partly due to greater attention having been paid to this celebrated limestone by collectors.” In commenting upon this sagacious inference Dr. Traquair notes that “this explana- tion of a supposed fact has indeed proved to be true even in a more emphatic sense than is implied by the word ‘partly’ As regards the fishes, at least, if we leave out of consideration the names cancelled above, all the species contained in the Burdiehouse list, except Megalichthys laticeps and Uronemus lobatus, occur in the Dunnet Shale above and many of them in the Wardie Shales below.” + The following is a vertical section of the Burdiehouse strata quoted from Hibbert’s description : {— a. Argillaceous and bituminous shale of a very dark colour, alternating with which are thin seams of ironstone, and three or more very thin seams of limestone, the latter being from 2 to 2} in. thick, and at intervals from each other of 27 to 36 in. From 30 to 50 ft. of shale are exposed. b. The limestone of Burdiehouse, 27 ft. thick. c A pavement of rather soft blaes, 2 or 3 ft. thick. This is an argillaceous and bituminous shale mixed with calcareous matter, and forming, near the junction of the rock, or immediately subjacent to it, an impure limestone. *“ The Geology of the Neighbourhood of Edinburgh,” 1861, p. 146. + Trans, Roy. Soc. Edin., 1903, vol.-xl. p. 692. { Trans. Roy. Soc. Edin., 1833-4, vol. xiii, p..244. 166 The Mid-Lothian Basin. d, Limestone of inferior quality, 3 or 4 ft. thick. e. Black blaes (argillaceous and bituminous shale), rather soft, 3 or 4 ft. thick. f. A seam of coal, 6 to 10 in. thick. g. “Yellow clay” (an argillaceous and shaly sandstone 2). Some of the workmen describe this bed as metal, and as forming a very coarse freestone. Depth unknown. The beds of argillaceous shale, both above and below the lime- stone, contain the same organic remains as the latter. The limestone is regularly stratified and of various tints, often bluish grey or blackish grey from the bituminous or vegetable matter which is so abundantly diffused through it. It possesses a dull and earthy fracture, the rock being charged with innumerable tests of ostracods. It breaks very readily along the bedding planes where the bands of limestone alternate with thin lamine of vegetable or bituminous matter. Where these are absent it breaks with a conchoidal fracture. For over one hundred years the limestone has been opened out by a series of quarries between Straiton and Burdiehouse Mains. To the south-west of Straiton its position has been proved by numerous bores, and to the south of Pentland Mains there are traces of several old quarries. From this point to the west of Penicuik it cannot be traced, but it is possible that it extends to the south of the Glencorse Burn, for below Crawley Cottage cementstone bands are exposed in this stream. This bed is at present only wrought at two localities: at the Straiton Oil Works by a pit sunk 50 fms. with stoop and room workings, and at the opencast quarry to the east of Burdiehouse Mains by a mine 160 fms. in length. The workings along the north face of this mine have proved the position of an east and west fault with 60 fms. downthrow to the north, to which reference has already been made. The average dip in the quarries is 20° to 30°, and in the underground workings 47° to the south-east. To the south-east of the quarried outcrop of the Burdiehouse Limestone between Pentland and Burdiehouse Mains is situated the oil-shale field recently wrought by the Clippens Oil Company. The proved ground is two miles in length with an average breadth of 600 yds. and contains several workable seams. The oil-shales above the limestone are shown in the following section :— PaPER SHALE Ft. In, Strata to .. as a ae z3 re -» 1338 O Houston CoaL Strata to.. As ki ae is dig . 51 8 TWENTY-INCH CoAL Strata to.. oe a a i a . 46 8 FELiLs SHALE Strata to.. is ois ua iS Me .. 145 1 BroxBuRN SHALE Strata to.. ac eae wis oe ae .. 264 11 Dounwet SHALE Strata to.. es 3 Pa Pa A .. 177° ~ 0 --- - BURDIEHOUSE LIMESTONE. The actual outcrops of the Dunnet, Fells and Broxburn Shales have been proved by mining and the remaining coals and shales by Calciferous Sandstone between Straiton and Glencorse Burn. 167 bores and trial pits. A glance at the map will show how closely these different seams follow the outcrop of the limestone. To the south of Pentland Mains the two lowest shales are thrown into four successive folds, but apart from these flexures the structure of the field is very simple. It is crossed by no faults of any importance and the different beds dip to the south-east beginning at 44° and increasing to 58°, The Dunnet Shale is from 5} to 6 ft. thick, yields from 25 to 26 gallons of oil and 20 to 23 lb. of sulphate of ammonia per ton of shale, and is rich in solid paraffin, known technically as “scale.” The roof of this seam is composed of soft friable blaes which is a disadvantage in mining the shale, The roof and floor of this bed have yielded a rich fish fauna to Dr. Traquair.* He remarks that “of the twenty-one accurately determined species here recorded, twelve occur in the Burdiehouse Limestone below, which was considered to be a ‘fresh-water lime- stone’ by Dr. Hibbert. Fragments of cephalopodous shells in the roof-shale bear witness to the fact that marine conditions were not far off, and that ‘estuarine’ is rather a better word in the circum- stances.” The Broxburn Shale gives from 20 to 22 gallons of crude oil and 20 to 21 1b. of sulphate of ammonia per ton. It has astrong roof and is more cheaply wrought than the Dunnet Shale. It shows the following section :— Ft. In Blaes .. 2 0 Ironstone BAanpD 0 6 Blaes .. 304 SHALE... 3.3 Irony rib 0 1 Blaes . . 1 5 The Fells Shale, on account of its thinness and hardness, would not be a workable seam were it not for its extreme richness, yielding 34 to 35 gallons of crude oil and 10 to 19 1b. of sulphate of ammonia per ton. The Twenty-inch and Houston Coals are both thin and dirty, and have never been worked in this field. The Paper Shale has been opened out at its outcrop and is a thin, finely laminated shale. It has never been wrought and may be the equivalent of the Raeburn or Mungle Shale of West Lothian. The section in the Pentland cross-cut mine is given in the sub- joined table, and the Broxburn section is placed alongside for comparison. In the Pentland section the Binny Sandstone is 65 ft. thick and at Broxburn 277 ft. In the eastern field three limestones with a total thickness of 41 ft. lie above the Binny Sandstone, which are not found in the Broxburn field. The Broxburn marls are not represented in the Pentland section. * Trans. Roy. Soc. Edin., 1903, vol. xl. p. 692. 168 The Mid-Lothian Basin. Comparative Table of Strata in Pentland Cross- Cut Mine and at Broxburn. Pentland Cross-Cut Mine. SHALE, FELLS Fakes Ironstone with thin bands and Blaes Sandstone .. Blaes Rock Blaes Sandstone .. Blaes Sandstone .. ae $ and Blaes * hard Blaes LIMESTONE, dark Blaes SHaAxz, brown Blaes SHALE, poor .. Suatz, BRoxBurn Blaes SHALE Daugh LIMESTONE Blaes LIMESTONE Fireclay LIMESTONE, hard Fireclay Sandstone .. Daugh Sandstone .. Blaes Sandstone .. Blaes Ironstone SHALE.. Blaes Daugh Blaes SHALE, DUNNET Blaes LIMESTONE Fakes ws Faky Sandstone Hard faky Sandstone Fakes : - Faky Sandstone Kennel Blaes z LIMESTONE, Burdiehouse Ft. In. | I 8 8 10 24 13 es He a DdeH NAD OWWRDOWORFHWOWNONOWARwWOUWOr RW e POOORAWO DC TCOARDOABNWNKHOCSTCOCHOAWDWDOARBWWDADDOOCNWNWKRADCOHWRADOADS De owe 60 Broxburn. ; Ft. In. SHALE, FELLS 3 0 Blaes 5 0 LIMESTONE 4.0 Hard Marls . 248 O SHALE 11 Blaes and ribs 12 3 SHALE 0 8 LIMESTONE 0 6 SHALE 1 6 Blaes 3 10 SHALE, grey 5 10 Blaes 5 64 SHALE, curly .. 5 66 Blaes 4 0 SHALE, BROXBURN 5 60 Blaes 19 O Marly Fakes 69 0 Blaes and shaly Blaes 29 2 Binny Sandstone .. . 277° = 4 Sandstone and faky Blaes.. 46 10 Faky Blaes.. : -- 2 3 SHALE .. 0 4 . O 8 Blaes ‘i a oa LEO 5 SHALE, DUNNET cs .. 4 10 Blaes ar ae war OS IG Limy Sandstone .. 84 6 Blaes : . 127. 6 Sandstone and Blaes . 1838 10 LIMESTONE .. ae we ok) Blaes a .. 66 8 SHALE, BARRACKS .. - O 6 Blaes As . WW 68 LIMESTONE... ll 2 Smnistone| Burdie- 30 0 LIMESTONE house O 4 1216 1 The position of the Burdiehouse Limestone, as shown on the map on the west side of the Straiton anticline, is inferred from bores. Calciferous Sandstone between Straiton and Glencorse Burn. 169 The Dunnet and Fells Shales have been got in the basin to the west, and the latter seam at Broomhills Farm appears in an inverted synclinal fold. The exposures are disconnected. East of Broomhills Farm the beds in the Burdiehouse Burn dip to the south-east at very high angles and are sometimes vertical. They consist of black blaes with a bed of oil-shale. At the edge of the burn below the farmhouse a mine has been driven for a short distance into the shale, which is reported by Mr. Gemmell to be the Fells and about 2 ft. 6 in. thick. This seam occupies a small com- pound synclinal trough with steep sides. The shale was tested but found to be unsatisfactory. Between Broomhills and the Pentland fault a 4-ft. curly shale has been uncovered which was believed to be the Dunnet Seam. On the east side of the compound synclinal fold, and at the edge of the flat ground below Broomhill Cottage, this same shale was opened out by a pit. It dipped to north-west, was 4 ft. 7 in. thick and proved to be the Dunnet Shale lying about 130 ft. above the Burdiehouse Limestone. Oil-shale crops have been opened out at various places between the Kames and Hyvots Bank, and at St. Catherines Well crude paraffin is found floating on the surface of the water. Some years ago the South House property was bored, but the results were not satisfactory, although they were not such as to preclude the possibility of finding a valuable field to the north of the Burdiehouse fault. Above the Paper Shale of Straiton there is no section to indicate the nature of the strata for 561 ft. of vertical thickness. The section in the Bilston Burn commences on the east side of the Edinburgh road with a cream -coloured encrinital limestone. Eighteen feet above this horizon is a bed of blaes with oil-shale bands, which is overlaid by a grey encrinital limestone, 1 ft. thick. Next in order comes a calmy calcareous mudstone, 4 ft. thick, which has been termed the Cephalopod Limestone. Various strata, aggregating 73 ft. in thickness, separate this characteristic horizon from a coal reported to be 2 ft. thick, the latter seam being overlaid by 723 ft. of beds, on top of which comes a very peculiar light-coloured lumpy fireclay with nodular concretions. Reference has already been made to the occurrence of the Cephalopod Limestone and the lumpy marl or fireclay in the Burdiehouse Burn section, near Gilmerton, which together with the RAipidomella [Orthis] shale and fish band enabled Mr. Macconochie to institute a comparison of the sequence of strata below the Gilmerton Limestone in the two sections (Fig. 14). The close correspondence in the sequence of zones in these two sections seems to involve the acceptance of an ochre bed (21 ft. thick) as. the decomposed *. representative of the Gilmerton Limestone (60 ft. thick). This correlation had been already reached on account of the close lithological resemblance of the sandstones above the ochre bed and limestone respectively, and also because both lie about 100 ft. beneath the North Greens Coal. Another important point is the correlation of these Mid-Lothian sections with that on the Fife coast near Kinghorn, which Mr. _* Cf C. T. Clough, “ On the Disappearance of Limestones in High Teesdale,” Geol. Mag., 1903, p. 259; and C. A, Matley, Q.J.4.8., 1906, vol. lxii. pp. 291, 293. as 170 g 08 The Mid-Lothian Basin. Macconochie’s discovery of the fish bone bed has rendered possible. From general stratigraphical relations it will be readily conceded that the thin limestone beneath the Gilmerton (and ochre bed) might represent the first or lower Abden Limestone of Fife, so that when it is found to be underlain bya shale with Rhipidomella and GILMERTON SECTION. BILSTON BURN SECTION. GILMERTON LIMESTONE. ——— Sandstones Dark Fireclay IRONSTONE with plants Dark Shale rer Flaggy Sandstone a Yellow Sandstone. sx] COAL (impure) 1’ 6.” u 7 =| LIMESTONE & IRONSTONE with plants. Sandy Shale Soft Yellow Sandstone Black Shale .| faky at base. Dark Limestone andy Shale Black Shale with band at base. Dark Limestone R=] Argillaceous Shale with Fossiliferous Tronstone Nodules, Dark Calcareous Shale with Limestone Nodules Dark Fissile Shales. paris Shaly Limestone SET LIMESTONE (Calmy). . Encrinital Bed overlying =>] LIMESTONE (Encrinita)). Rhipidometia Shale & Fish Bed Rhipidomelia Shale & Fish Bed. e Dark Shale Grey Shale with Ironstone Nodules COAL (Parrot) 6” Grey Shale resting on == Faky Sandsto.s SS Dark Fissile Shale. SPLINT COAL 5”. Grey Shales. Concretionary Marls or Fireclays. ‘,"* {I pigsile Sandstone. Grey Shales. Fic. 14.—Comparative Sections of Strata below the Gilmerton Limestone in Burdiehouse Burn and in the Bilston Burn (scale 40 feet=1 inch). this in turn by a bed charged with fragments of Zingula and fish remains, just as in the Fife section, the grounds for correlation seem reasonably conclusive. It may be noted, however, that Dr. Traquair, who has determined the fish remains present, regards the bone bed by itself as inconclusive, for much the same assemblage of forms might be expected in any bone bed about this horizon. But the Calciferous Sandstone between Penicuik and Carlops. 171 crucial evidence that helps to fix the horizon is the stratigraphical relation of the bone bed containing Zingula to the shale with Lhipidomella and the limestone. J8.GW., EBB PENICUIK, CARLOPS AND RUTHERFORD AREA, The area extending. from Penicuik to the south end of the Mid- Lothian basin at Rutherford in Sheet 24 presents features of consider- able interest owing to the attenuation of the Oil-shale group in that direction, to the thinning out and disappearance of some of the workable seams, and to the evidence of unconformable overlap of the members of this group on to the denuded platform of the Lower Old Red Sandstone beyond Rutherford. The area is also noteworthy owing to the occurrence in it, not far above the Burdiehouse Lime- stone in the Esk section, of a volcanic zone which is almost immedi- ately overlain by an oil-shale of good quality, termed, for convenience of reference, the Carlops Oil-shale. No less interesting is the appearance of thin marine limestones, detected by Mr. Macconochie, beneath the Burdiehouse Limestone, in the Esk, yielding a remark- able assemblage of organic remains, comprising brachiopods, bryozoa, lamellibranchs, gasteropods and cephalopods (see description by Dr. Lee in Appendix I. p. 369). Recently various bores have been put down in this area by Charles Edward Allan, of Stormont Castle, Belfast, who has kindly allowed the Geological Survey to examine the rock-cores and has furnished copies of the bore journals. As the boring operations are incomplete we are desired to confine ourselves at present to a brief statement of the results. The Carlops Oil-shale, of good quality, and the underlying voleanic zone have been proved to extend south- wards to Rutherford. Northwards, at the Eight Mile Burn, a bore beginning near the base of the Carboniferous Limestone series passed through several oil-shales—one of good quality—together with olivine basalt lavas of the Bo’ness type, and reached an ento- mostracan limestone resembling the Burdiehouse Limestone of the North Esk. The North Esk Section.—The best natural section of the Oil-shale group in the Mid-Lothian basin is to be found in the North Esk below Carlops Bridge at the southern margin of Sheet 32, where the belt of Calciferous Sandstone strata between the Pentland fault and the base of the Carboniferous Limestone series is about a quarter of a mile in breadth. Both in the North Esk and in a small tributary, named the Amazondean Burn, to the north the beds are usually inclined at high angles and are in places inverted, but the sequence is remarkably clear. During the former survey of the district, the two thin bands of limestone visible in the Esk, not far below Carlops Bridge, were regarded as representing the position of the Burdiehouse Limestone*—a view which has been adopted during the recent revision. Beginning at Carlops Bridge where the Lower Old Red Conglomerate is seen in the river with signs of fracture evidently produced by the Pentland fault, we find the lowest visible Carboniferous strata in the stream about 120 yds. below the bridge, where they consist of * “ Geology of the Neighbourhood of Edinburgh,” Geol, Sur. Mem., 1861, p. 37. 172 The Mid-Lothian Basin. pebbly sandstones, faky sandstones and shales. In a scar at the bend where the river flows to the N.N.E. these beds are overlaid by green and red clays, shales and calcareous ribs, surmounted by pebbly grits and fine conglomerate with pebbles of radiolarian chert, vein quartz and Lower Old Red Sandstone lavas, some measuring an inchacross. From this point downwards for a distance of 300 yds. to the exposure of the Burdiehouse Limestone, the strata appear mainly on the eastern bank of the stream, and consist largely of green and grey sandstones, grits, shales and mudstones dipping easterly at angles varying from 30° to 50°. Intercalated in this series, we find the marine zone already referred to, about 20 ft. thick, com- prising the following subdivisions in descending order :— Thin limestone with marine fossils. Strata. Thin lamellibranch limestone from 6 to 8 in. thick. Strata. Calcareous sandstone or sandy limestone with plant remains. Clayey shales. Calcareous shale, about 1 ft. in thickness, highly decomposed and crowded with marine fossils, chiefly lamellibranchs. About 20 ft. below the position of the Burdiehouse Limestone there is a band of calcareous conglomerate or sandy limestone with Leperditia, about 3 ft. thick, which is visible on the east bank and may probably represent the entomostracan limestone at Rutherford to the south-east, in Sheet 24. The two bands of yellow cream-coloured limestone—the lower measuring 3 ft. and the upper 6 ft. in thickness, which in all ‘probability represent the position of the Burdiehouse Limestone—are separated from each other by about 30 ft. of green sandstones and shales. Fossils are not abundant, but,in the upper band, entomo- straca, fish remains and coprolites were obtained. After crossing about 30 ft. of strata, the volcanic zone appears in the river at the point where it changes its course towards the east. It consists of a basalt lava overlain by a thin band of tuff, 3 in. thick, crowded with fish scales, which is, in turn, succeeded by a bed of decomposing entomostracan limestone about 2 ft. thick. At this point in the section, in a scar on the right bank, the first oil-shale (the Carlops Shale) occurs with thin intercalations of grey shale and a lenticular seam of Spirorbis limestone, containing entomostraca. This oil-shale is of good quality and may represent the Dunnet Shale in the Straiton section. Descending the stream for a distance of about 60 yds., we encounter a thin oil-shale of inferior quality,.resting on a bed of limestone, 9 in. thick; charged ‘with entomostraca and fish remains. A few yards farther down another prominent scar on the right bank displays a third oil-shale of poor quality, interleaved with grey shales, the beds dipping to the east at angles varying from 70° to 80°. In the middle of this zone, a thin seam of decomposing shale occurs, from which Mr. Macconochie has obtained excellent specimens of the following arthropods, deter- -mined by Dr. Peach, namely: Cyclus testudo, Crangopsis eskdalensis, C. elegans, Perimecturus and Palemysis. The occurrence of this assemblage Calctferous Sandstone between Penicuik and Carlops. 173 at this locality is of special interest, as the forms are almost identical with those collected from the “ Scorpion Beds” of Glencartholm, near Canonbie, in Dumfries-shire, which occur there in the higher part of the Calciferous Sandstone series. From the third band of oil-shale down to the junction of the Amazondean Burn with the Esk, the observer crosses a succession of dark-grey and blue shales, grey and yellow sandstones, and blue calmy shales, which are followed by a fourth band of oil-shale of inferior quality resting on a thin seam of calcareous shale charged with Pleurotomaria. At this point the sequence is interrupted by a fault crossing the North Esk in a N.N.W. direction with a down- throw to the east, whereby the fourth seam of oil-shale with its underlying Pleurotomaria band has been shifted for a distance of 200 yds. to the north, reappearing in the Amazondean Burn not far above the farmhouse of that name. The rock exposures in this tributary are not continuous, but certain fossiliferous zones have been there identified by Mr. Macconochie, which have been of service for the purpose of correlation. Descending the burn from the point near the high road, where the Pleurotomaria band and accompanying oil-shale occur in inverted order (I in Fig. 16, p. 184), and are followed by sandy fakes, the observer, after crossing further outcrops of grey and dark shales, meets with an exposure of calmy limestone containing cephalopods and encrinites (the Cephalopod Limestone, IT in Fig. 16, p. 184), succeeded by bituminous shale. This calcareous subzone, likewise inverted, is followed by ripple-marked dark and grey fakes and by a coal formerly wrought. A few feet above this seam an important horizon is met with (IIT in Fig. 16, p. 184), consisting of a bed of limestone, 3 ft. thick, yielding encrinites and Productus semireticulatus, underlain by a thin band crowded with Rhipidomedlla [Orthis] and a peculiar shale charged with fragments of Zingula and some fish remains (the Bone Bed of the Burdiehouse Burn). As already indicated, these paleontological horizons—the encrinital limestone, the Rhipidomella shale and the fish band—have been detected in the same relative order in the Bilston and Burdiehouse Burns to the north (p. 170). Farther down the Amazondean Burn the Productus limestone is twice repeated by folding. If we assume that the entomostracan limestone beneath the Carlops Oil-shale in the North Esk represents the Burdiehouse Limestone, then it follows that the sections just described furnish us with a more or less continuous sequence from the Burdiehouse Limestone to the Bone Bed and its overlying calcareous seam, which may be the equivalent of the Lower Abden Limestone of the Fife coast. Nine Mile Burn—tIn this stream the higher members of the Calciferous Sandstone are brought to the surface along an anticlinal fold in the overlying Carboniferous Limestone series (Chapter XL, p. 185). The sequence of the Oil-shale group on the western limb of the arch is alone exposed, as the Gilmerton Limestone and underlying Calciferous Sandstone strata on the east limb are cut out by a fault. Not far from this dislocation the Pleurotomaria band and its overlying oil-shale are met with in the stream dipping steeply to the W.N.W. They are followed in ascending order by 174 The Mid-Lothian Basin. dark shales with two thin limestones, sandstones, shales and a thin coal. At the bend in the burn we pass up into the Carboniferous Limestone strata, the position of the Gilmerton Limestone being indicated by a bed of ochre, to be referred to in the sequel (Chapter XL, p. 186). Along the narrow belt of Calciferous Sandstone strata extending northwards from the Nine Mile Burn to Glencorse, scarcely any solid rock is exposed, the stream sections being cut mainly through boulder clay. But, as already indicated, the presence of the Oil-shale group with several seams of shale has been proved by boring operations -near the Hight Mile Burn. B.N.P., J. H. Recent boring operations in the ground between Carlops and West Linton, a short distance beyond the limit of the present Map, render it advisable to call attention to the further extension southwards into the adjoining Sheet (24) of the Calciferous Sandstone strata found along the river Esk, in the section just described. The position of the lower limestones is fixed a short distance to the east of Rutherford, the lowest bed being well exposed in Whitefield Quarry. Ata point on the Deep Syke, one-third of a mile below the Carlops road, and half a mile south by west of Rutherford Mains, a hard sandy light grey limestone containing entomostraca is exposed for some distance along the bed of the stream, the beds being almost horizontal. As this entomostracan limestone may be correlated with ‘the band which lies 20 ft. below the Burdiehouse Limestone in the Esk section referred to above, it was natural to expect the oil-shale seams of that section to occur in the ground between the outcrop of this entomostracan limestone and the marine limestones east of Rutherford. As already stated (p. 171), this expectation has been fully confirmed by bores recently put down. _ Further reference may be made to a series of trial bores put down some years ago by the Clippens Oil Company in the ground immediately to the south-east of Whitefield, a mile west of Macbie Hill Station, and approximately half a mile west of the outcrop of the lowest of the Carboniferous limestones. In two of these bores, an oil-shale, 4 ft. in thickness, was proved at a depth of 8 fms. The result of the trial borings did not at the time seem to warrant further operations, but the presence of oil-shale at this locality, in what appears to be a similar stratigraphical position to that of the shales proved at Rutherford, is interesting as indicating the probable occurrence of workable oil-shale over a considerable area between Carlops and Macbie Hill. LW. HL BORTHWICK, MIDDLETON AND TYNE WATER. From evidence obtained in the ground farther to the north-east (Sheet 33), it is probable that the lowest members of the Carboni- ferous formation, which cross the extreme south-eastern corner of the Map, are in faulted relations with the Silurian strata along the northern face of the Moorfoot Hills. Owing, however, to the thick covering of boulder clay, which inasks the lower hill-slopes, the nature and exact position of the Calciferous Sandstone of Middleton and Tyne Water. 175 boundary line between the two formations over Middleton Moor is to a certain extent conjectural. The lowest beds of the series seen in this part of the area are well exposed along the South Middleton Burn, which joins the North Middleton Burn at Borthwick to form the Gore Water. At the entrance of the Currie Glen, soft red and white sandstones with marly bands are seen in an old quarry in the wood, and similar rocks form the high banks of the stream within the glen on the north side. At the base of these sandstones the stream flows for some distance over the upper surface of a volcanic zone, the various members of which—loose decomposing ash, tuff with nodules of cherty rock, and a hard pillowy lava—appear at many points in the banks and bed of the burn. Close to the sudden bend made by the stream to the south, the volcanic rocks are cut off by a small fault that crosses the bend; and about 100 yds. farther up stream they are again truncated by a more powerful dislocation running approximately east and west, with a downthrow to the south, which may be as much as 50 or 60 ft. By this fault the sandstones that overlie the voleanic zone are brought down to the bed of the burn, where they aré seen in conjunction with a coarse agglomeratic ash. Red and yellow sandstones and marls appear almost continuously along the burn from this point to Currie Farm, but the stream is flowing nearly along the strike, and no great thickness of strata is passed through, The beds are dipping N.W. to W.N.W. at low angles. At the side of the road leading up from the stream to Currie Farm, a thin coal associated with soft yellow sandstone is exposed ; while dark shales underlie the drift just above the farmhouse. The occurrence of these beds is important, as proving the red sand- stones of the Currie Glen to lie within the Calciferous Sandstone series. Returning to Borthwick and following the course of the North Middleton Burn, we find a considerable distance in which exposures of rock are few and often widely separated. The non-appearance of the oil-shales in this position may possibly be accounted for by this discontinuity in the sections; but from the observation made by Mr. Bailey in the ground to the east, it seems more probable that they are cut out by a powerful strike-fault with a downthrow to west, whose course is indicated as crossing the stream at Borthwick. : The upper beds of the Calciferous Sandstone seen in the North Middleton Burn are, in ascending order,—red and yellow false- bedded sandstones with soft variegated marls; hard yellow : gritty sandstones and coarse pebbly grits; and, immediately underlying the lowest of the Carboniferous limestones at North Middleton, sandstones and dark shales with ironstone nodules. L. W. H. Below the Carboniferous Limestone series of Tyne Water we find a considerable thickness—probably 100 ft. at least—of alternating sandstones and marls, the former often red and the latter purplish- grey and white. CB Ces CHAPTER XI. CARBONIFEROUS LIMESTONE SERIES OF THE MID-LOTHIAN BASIN. Lower LIMESTONE GROUP. OnE of the most difficult questions connected with the stratigraphy of the Carboniferous Limestone series in the Mid-Lothian basin is the correlation of the lower limestones on the east side of the syncline with those on the west. The Gilmerton Limestone, which, as already stated, is taken as the base of this series on the west, has a striking resemblance lithologically to No. 2 Limestone of Tyne Water, but it is probably on a lower horizon being below the position of the North Greens Coal. For this reason different designations have been given to the lower limestones on either side. The names of the chief calcareous zones on the east are given below in descending order— No. 3, or Chapel Point Limestone. No. 2, or Skateraw Limestone. No. 1, or Longeraig Limestone.* On the west side of the basin the chief lower limestones are termed in descending order— The Bilston Burn Limestone, The Vexhim Upper and Lower Limestones. The North Greens Limestone. The Gilmerton Limestone. _ The lower limestones are unusually thick at the south end of the syncline, where in some places they seem to coalesce without any intercalations of sandstone or shale. On the western limb of the basin the Bilston Burn displays a remarkably clear section of the Lower Limestone group, and indeed of the Carboniferous Limestone series as a whole (see Fig. 15, p, 181). No such satisfactory section is to be found on the east side, but it is certain that some of the lower limestones there must differ consider- ably in character from those with which they correspond strati- graphically on the west. The coast sections at Aberlady, and between Dunbar and Cock- burnspath, form connecting links between the counties of Mid- Lothian and. Northumberland, for part of Limestone No. 2 of Tyne Water, Mid-Lothian, is believed to correspond not only to the Skateraw Middle Limestone of Dunbar, but also to the Acre Limestone of Northumberland, and Limestone No. 1 of Tyne Water is regarded as the representative of the Longcraig * These names are taken from the localities on the coast near Dunbar, where the supposed representatives of these limestones are best seen. 176 Lower Limestone Group of Niddrie. 177 Limestones of Dunbar and also of the Eelwell Limestone of Northumberland.* : CT. Gs JOPPA, NIDDRIE AND GILMERTON AREA. On the shore at Joppa the strata are covered by sand and drift, but indications of the limestones were found in digging the founda- tions of houses at the east end of the town. A section of the group was measured in 1893, in a cross-cut mine situated a little south of the Brunstane (Burdiehouse) Burn, by the firm of Mr. William Gow, and has been communicated by Mr. Martin, Manager of Niddrie Collieries. The most important details of the section are shown below in descending order. The distance from the Carleton Coal is stated for the sake of comparison with the Gilmerton section, which is given in the sequel (p. 179). Ft. In. Various Strata, starting from the base of the CaRLETON Coat and including the position of the BLuE Coat... a ac .. 99 10 Faky blaes i a se ne .. 57 5 BILSTON BURN LIMESTONE .. ee “3 w« 14 9 Blaes 6 ne ae ne a3 .. 165 7 Sandstone and blaes_.. & 2 we oA, OP Blaes ss a 2 3 ae . 1 4 Cement (UPPER VEXHIM LIMESIONE) .. . 38 8 Sandstone and blaes_.. ie a ya Wd. 9 Nippris Vexum™ Coat (foul) es ss ce 2 6 Fireclay .. aH a 6s . 12 4 CoaL .. ee oe a se ae web) 0 Coarse sandstone es ae ts .. 69 8 Blaes au ae er te 3 . 10 7 Sandstone he ae a3 Ai .. 54 I1 Blaes me Sr ee i as .. 28 10 LIMESTONE 33 ig <6 B< 3 . 9 10 : Blaes 2 a mi Se Ee ox, AB 7 aa LIMESTONE 4% xs an ne whe .. 18 1 ® Blaes sa ak 24 ‘k 3 . 18 1 LIMESTONE... ae Be ae Be . 6 7 Blaes oa ae ee oe oi ss Th “9 RoueHParror(CoaL .. a ox Pe 28 es we Lf -0 Coat of | Blaes is as ia me ifs .. O 10 Loanhead. (Coat .. a ie iat ss 4 we Ae 76 Sandstone 35 ee 23 ne ge 13.11 Blaes aes pe 34 he . 18 1 Nort Greens Coan Rowek cs a = - a The North Greens or Jewel Coal, shown at the bottom of this section, contains an excellent seam of Parrot and is reported to be one of the best seams in Mid-Lothian. In Brunstane Burn the “cement” band and the “coarse sandstone” of the section can be recognised, and between the burn and the sea the outcrops drawn on the map cannot be greatly in error, for Mr. Milne Homet records the occurrence of the Gilmerton and North Greens Limestones at * W. Gunn, “ Correlation of the Carboniferous Rocks of England and Scotland,” Trans. Edin. Geol. Soc., vol. vii. p. 361, plate xx.*; also Geol. Mag., 1898, Dec. iv. vol. v. p. 342. C. B. Crampton, “ Iimestones of Aberlady, Dunbar and St. Monans,” Trans. Edin. Geol. Soc., vol. viii. p. 374. + “Memoir on the Mid-Lothian and East Lothian Coal-Fields,” 1839, p. 88. 12 178 Carboniferous Limestone Series of Mid-Lothian Basin. Duddingston Mains, and the crops of both the North Greens and Vexhim Coals have been opened up just south of the main line of the railway. The Gilmerton Limestone was formerly worked close to Niddrie House, but the quarries are now entirely filled up. South- wards from this point to the Ferniehill Quarries there are no exposures, but the crop of the North Greens Coal is known from mining information. Along this part of their course the various outcrops are deflected so as to run almost north and south instead of N.N.E. and 8.S.W. At Ferniehill, half a mile due north of Gilmerton, the cause of the deflection becomes evident, for the Gilmerton Limestone may there be traced in a line of quarries round the nose of an anticline, the axis of which runs due north and south and pitches about 15° to the south. The Lower Limestone and Edge Coal groups between Niddrie and Ferniehill lie on the east side of this anticline, and their inclinations have been steepened and their outcrop narrowed by it. These effects are best known in the Edge Coal group, to which belong the vertical strata of Drum Quarry and the overhanging seams of No. 11 Pit (of Niddrie), just north of Edmonstone, which have been figured by My. Martin.* In the Moredun Quarries, which run to the north-west near Fernieside, the Gilmerton Limestone lies on the west side of the anticline and in the most northerly quarry dips almost due west at an angle of 45°. The anticline described is not directly continued farther south than Gilmerton, but its place is taken by another starting at Hyvots Mill and running 8.8.W. through the village of Pentland, the continuation of which appears in the Straiton arch (Fig. 13, p. 163), The westerly dip of the western limbs of the two anticlines is not continued up to the Pentland fault, for the beds are quickly brought up again, sometimes dipping steeply to the E.S.E., sometimes even showing a reversed dip. This is well seen in the Burdiehouse Burn south of the Gilmerton Road, where some dis- tinctly ripple-marked flagstones overhang at an angle of 45°. Near this point a part of the Gilmerton Limestone is exposed, but, owing to a small fault, less than half of its full thickness is seen in the stream section. One result of the folding described has been the production of the shallow little basin of Gilmerton, in which we find outliers of the North Greens Coal and Limestone. The North Greens Coal in this basin has a thickness of nearly 4 ft. 6 in., of which 1 ft. 6 in. is parrot, and the rest a rough coal. It is separated from the lime- stone above by 17 ft. of sandstone and shale. The Bilston Burn Limestone, which is not now visible north of Gilmerton, crops out immediately to the east of Gilmerton House, and was passed through in a pit sunk to the North Greens Coal. It is reported that the limestone is here 5 ft. thick, and is overlain by 19 ft. of calcareous shale, and that the coal, locally called the Vexhim, which lies below the limestone and is separated from it by 11 ft. of black shale, is 2 ft. 2 in. thick. The following section of the group as developed at Gilmerton is based on information given by Mr. Marshall, Mining Engineer, Edinburgh, except as regards the thicknesses below the North Greens *“The Mid-Lothian Coal Basin,” Trans, Min. Inst. Scot, vol. xv. pt. iii, p. 164, Lower Limestone Group of Gulmerton. 179 Coal, which have been obtained by protraction from the surface. The positions of the Carleton and Blue Coals are given so as to allow of comparison with both the Niddrie and Loanhead sections :— Ft. CARLETON CoaL .. aks oe ae a 5 Strata ae ae és 6 .. 84 Buus Coan i 3% Pa 5 <3 7 Strata * a ea iS we .. 90 BILSTON BURN (LIMESTONE blaes .. sf 6 a . 19 LIMESTONE. \ LIMESTONE he sia hes ‘e a 5 Blaes Se is ae ad Coa, VEXHIM of Gilmerton Blaes i oa Coan Freestone Blaes Sandstone Blaes : a LIMESTONE blaes (vee VEXHIM c untEstox) Coan : i 2a ae 5 Fakes Blaes is Freestone post and fakes .. Blaes with ironstone balls Fakes ns eg LIMESTONE blaes (LOWER. VEXHIM tantestox) a Blaes rs 4 At OAL Halas bx Coat, fine spling VBE of Niddrie i ‘ Freestone and fakes az in Blaes 2% oT, ek sch fan 2 Carlet 5 2a Coa Blaes A Be i ea as Red sandstone sh a a8 .. 146 Blaes als aid ay 5 . 91 | Blaes wis es Ls oe .. 57 oO ad do Ph We SB DO — bo DOM ODEN KH QHYOOrTANO NORTH GREENS LIMESTONE. LIMESTONE 6 Blaes 3 Sandstone 1 Clay .. 0 Freestone and fakes 7 Blaes We a Oe 1 Sandstone (lakes) ss i es 1 Blaes j : eh i 6 1 0 0 3 None ie CoaL GREENS Coan. Hard band (ironstone 2) Fireclay Parrot and RovuaH Coa si ee Strata iste is as oi .. 110 Calcareous blaes .. ne Sie a 10 GILMERTON LIMESTONE .. 3 j -. 60 It will be seen that a small group of nailer occurs between the North Greens and Bilston Burn Limestones. The name Vexhim has been applied rather loosely in different localities to different coals of this group. Thus the Niddrie Vexhim is obviously represented at Gilmerton by the 3-ft. coal which lies about 35 ft. above the thick red sandstone. The latter’ constitutes a good horizon and SOSCDOMRODCOWOWODOWARODOROSCORDOARAROCWAROONONSOOOOOSCAE * The section between these beds and the base of the North Greens Coal is taken from the old Engine Pit near Gilmerton House. { This word is not known among miners, Perhaps it is a clerical error for “ clay,” 180 Carboniferous Limestone Series of Mid-Lothian Basin. is known to extend from Niddrie to Gilmerton and thence to the Bilston Burn. The word blaes is often applied to -argillaceous lime- stone as well as shale, and it. is probable that in the above section some of the blaes recorded represents argillaceous limestone, for the limestone portions of the North Greens and Bilston Burn seams, as shown in the section, are much thinner than oe are in Bilston Burn. The only accessible exposures of the group are those in the Gilmerton Burn and in the various quarries in the Gilmerton Lime- stone. The bottom portion of the Gilmerton Limestone, 10 ft. in thickness, is largely made up of the remains of encrinites. It was followed from the quarries underground in mines and is the only part which was ever quarried for burning. Above the 50 ft. of evenly bedded grey limestones, which follow the mined portion, we find about 10 ft. of dark calcareous shales which have yielded a considerable number of marine fossils. The shale is succeeded by a persistent group of flaggy sandstones. Although its position is not given in the above section a well- known blackband ironstone lies a little above the North Greens Coal, and contains fish remains. Dr. Traquair* states that the fauna indicates estuarine conditions, and resembles that of the Wardie Shales and the Oil-Shales, but differs entirely from that of the marine limestones. The band. has also furnished the remains of several labyrinthodonts. _* W,G, EB. B. LOANHEAD, BILSTON BURN AND MAURICEWOOD AREA. Three miles south of Gilmerton an excellent section of the Lower Limestone group is exposed in the Bilston Burn (Fig. 15), where the strata generally dip to the south-east at ages varying from 40° to 48°, In this stream immediately to the west of Pathhead we find a series of coarse ochre beds which, in the past, were worked for ochre. The largest of these, 214 ft. thick, is the representative of the Gilmerton Limestone, as already shown (p. 170). From information supplied by an old miner it appears that a limestone, which was identified as the Gilmerton Limestone, was quarried by him close to the farmhouse north of the stream and in the same line of strike as the beds of ochre. This statement is corroborated by old limestone workings at this spot, and additional evidence is thus furnished of the correlation of the Gilmerton Limestone with the ochre bed in Bilston Burn. In this connection it is interesting to note that in the Nine Mile Burn section, 73 miles to the south-west, the position of the Gilmerton Limestone is also occupied by an ochre bed of which 20 ft. is exposed (p. 186). Between Bilston Burn and Penicuik the Gilmerton Limestone is not visible, but in a bore to the south-west of Mauricewood Colliery it has been proved to have a thickness of 48 ft., and 100 ft. above it lies the North Greens Coal. A thin limestone is intercalated in the strata between these two horizons (see Fig. 15). “Distribution of Fossil Fish Remains in the Carboniferous Rocks of the Edinburgh District, ” Trans. Roy. Soc, Edin., 1903, vol. xl. pt. iii. p. 694. 181 Lower Limestone Group of Bilston Burn. paseyd ore spvog oyy Josemeu sy], “WING Uozs[Ig UT BIVIZG SHOLEJTUOgIED FO gouonbes oy4 SUIMOYS ‘a]IU T 0} SoyOUT g Jo epeos 943 UO de— GT “OLT ‘qolteg pur WITYXe A oY} Jo UoTydooxe sy} YITM ‘sures O44 OAOGB . yen ee vw oa! 00s 0 i LIS SO FTVIS Ai 182 Carboniferous Limestone Series of Mid-Lothian Basin. In the past the well-known North Greens Coal was extensively worked in the Gilmerton field, and has also been wrought to crop from the Sheriffhall and Burdiehouse fault to within a short distance of the village of Loanhead. In the Bilston Burn, in the hollow 70 yds. S.S.E. of Pathhead farmhouse, it was opened up some years ago by the Shotts Iron Co. where it furnished the following section :— Roof, sandstone. Ft. Coat, duffy .. ar is es at os en Coan 3 4} Pavement, grey fakes. In the Bilston Burn about 48 it. above the North Greens Coal there is a Rough Parrot Coal, 2 ft. 4 in. thick. At Loanhead this seam was worked in the Ramsay Pit till quite recently by means of a stone mine driven from the North Coal along the “ veese” of the Edgefield fault, from which the following sections were obtained :— Section, North Side Working. Roof, blaes. Ft. In. Coat, duffy ; ‘ os is is « OO 9 » Parrot as e a 8 a . O 8 » Splint... ee és a sa via se O 9 » Free 4 3. 63 5 (0 Section, South Side Working. Roof, blaes. Ft. In. Coat, Inferior .. Ss ae a xe Be - O 2 » Free ae Ha 3 ie i a - 0 6 » Splint .. wi 4 sis a as . 1 0 » Free oe ae 6 2 Between this point and Penicuik the North Greens Limestone has been proved in a bore on the south side of the Cuiken Burn to have a thickness of 10 ft. and to lie 40 ft. above the North Greens Coal. The Vexhim Coal of Loanhead and Niddrie lies a little above the North Greens Sandstone and is seen on the south side of the quarry close to Gilmerton House. It is a soft inferior coal, which has been wrought along the crop to Laverock Hall, where there is a mine, not being worked at present but formerly used to supply fuel to the Burdiehouse Limeworks. On the south side of the Sheriffhall fault the Upper Vexhim Limestone is exposed in the Edgefield railway cutting, where it consists of 4 ft. of limestone and 2 ft. of limy fakes. In the Bilston Burn the coal is 2 ft. 8 in. thick and is separated by 38 ft. of strata from the Upper Vexhim Limestone. It here lies 277 ft. above the North Greens Coal. Between Bilston Burn and Penicuik this coal and limestone have not been found. Ascending in the sequence we find the two Vexhim Limestones between the Vexhim Coal and Bilston Burn Limestone, a fact worthy of note as showing the marked development of calcareous zones in the Lower Limestone group. The Bilston Burn Limestone is not now seen at Gilmerton but was formerly worked in a quarry a little to the east of the present * “Geology of the Neighbourhood of Edinburgh,” Geol. Sur. Mem., p. 78. 184 Carboniferous Limestone Series of Mid-Lothian Basin. sandstone quarry at Gilmerton House. To the south-west it is first exposed in the Bilston Burn (Fig. 15) where its full thickness is about 50 ft., the bottom portion being a grey coralline limestone in beds which vary from 2 to 6 ft. in thickness, with thin partings of shale. The top bed is more impure and sandy and shows good Cauda-galli markings at the base. It lies about 50 ft. above the Upper Vexhim Limestone. Between Mauricewood and Mauricewood Pit this limestone has been uncovered and proved to be 180 ft. below the North Coal. To the west of Cuiken the position of this bed has been laid down on the map from boring information. In the Bilston Burn the thin limestone, 1 ft. 8 in. thick, which lies 41 ft. above the thick limestone just described, has been taken as the top of the Lower Limestone group. AREA BETWEEN PENICUIK AND CARLOPS. _ By far the best section of the Lower Limestone group between Penicuik and the village of Carlops is to be found in Habbie’s Howe ROAD AMAZONDEAN R.ESK Fic. 16.—Section of Calciferous Sandstone and Lower Limestone Group in Amazondean Burn and in Habbie’s Howe, North Esk, Carlops. on the North Esk, where the sequence of limestones is clearly displayed. Below Newhall House the strata dip steadily to the east, but are thrown into a series of folds as they approach the Pentland fault on the west, an anticlinal fold to the west of Newhall being succeeded by a compound syncline whose western limb is slightly inverted, the bed dipping steeply to the west. These folds are further modified by several faults, some of which are reversed. In the two sections about to be described, no less than five distinct bands of limestone have been recognised. The highest beds are comparatively thin, and it is evident that the upper bands, which, in the sequel, will be shown to coalesce at the south end of the basin, are here split up by the intercalation of non-calcareous strata. The top limestone (No. 5 in Fig. 16) crosses the Esk immediately below Newhall House, about 70 yds. above the footbridge. It is a dark calmy rock (14 inches thick), the upper portion crowded with small Producti (P. semireticulatus). It is succeeded by two thin S.E, Lower Limestone Group between Penicuik and Carlops. 185 coals, presumably in the position of the Vexhim Coals. From the point where the stream makes a sudden bend to the north, it flows for some distance along the strike of the next limestone (No. 4 in Fig. 16), which is seen in the right-hand bank. At the next bend, a rusty-weathering limestone, 6 to 8 ft. thick (No. 3 in Fig. 16), appears in the bed of the stream, while a thicker band—the North Greens Limestone—(No. 2 in Fig. 16) is seen in the bank on the north side. At the next footbridge a small fault with a downthrow to the east crosses the stream and brings up this limestone (No. 2) on the high southern bank where it forms a steep crag underlain by the North Greens Coal. Immediately above the bridge the river is flowing over the crest of the undenuded portion of the anticlinal dome, occupied by the lowest or Gilmerton Limestone and a small inlier of the underlying Calciferous Sandstone strata. On the west side of the fold the No. 2 band appears again, forming the linn, and is seen in the banks on either side of the stream at Peggy's Pool. This band is here 50 ft. in thickness, the lower portion thick-bedded and very fossiliferous, the upper 20 or 30 ft. made up of limestone bands and calcareous shale. A line of old pits to the south-west of the river shows where this limestone was at one time quarried along the outcrop. Between the linn and the next sharp bend of the stream, Nos. 3 and 4 limestones can be detected, but are badly exposed. The strata are now concealed for some distance until on the steep northern bank, about 40 yds. below Mill Bridge, a thin limestone—probably No. 5—is sharply folded with one of the lower Edge Coals. The strata beneath are now partly faulted out, and the next recognisable bed on the west side of the disturbance is the North Greens Lime- stone (No. 2), followed by the North Greens Coal and an underlying white ganister. This limestone has been quarried immediately above the bridge. The beds are now vertical or even inverted and dipping slightly to the west. The lowest (Gilmerton) Limestone does not appear in the river, being cut out by a small fault, but is seen in the small side stream on the south bank. Between this point and the foot of the Amazondean Burn, the section is occupied by sandstones and dark shales with lenticular masses of encrinital limestone, all belonging to the Calciferous Sandstone series. The ground to the north of the Esk is drift covered, and the limestones are next seen in the Nine Mile Burn, below the Carlops and Penicuik road. The structure exhibited in this section is a modification of that found at Habbie’s Howe. As in the latter locality, an anticline is followed by a syncline, but here the eastern limb of the former is inverted, and the centre of the fold traversed by a fault throwing down to the east; while the syncline is truncated on the west by the Pentland fault. The first limestone seen in the stream, at a point 500 yds. south- east of the Carlops road, is a yellow encrinital band, 4 ft. thick, which forms a small waterfall. This is No, 4 of the Habbie’s Howe section, No. 5 being cut out by a small fault which crosses the stream immediately above the outcrop of the lowest (North and 186 Carboniferous Limestone Series of Mid-Lothian Basin. South) Coal. Above this fault the beds dip steeply to the west, and follow one another up the stream in apparently inverted order. The yellow encrinite band is succeeded by dark shales; a limestone in two bands (No. 3), separated by shales; a thick sandstone; and No. 2, or the North Greens Limestone, below which the North Greens Coal, 2 ft. thick, was at one time wrought but is now no longer visible. The Gilmerton Limestone and underlying Calciferous Sandstone strata are cut out by a fault which crosses the burn 60 yds. above No. 2 Limestone. Two hundred yards below the road we pass again into Carboni- ferous Limestone strata, the position of the Gilmerton Limestone _being indicated—as in the Bilston Burn—by a yellow ochre bed, 20 ft. of which is exposed. The base is filled in with a siliceous network containing casts of Producti, Encrinites and branching corals. Beneath this ochre bed is a 1-ft. coal, resting upon a fireclay. A higher coal seam, which may be regarded as the North Greens Coal, has been wrought at Gardenfield, 100 yds. higher up the stream, and blocks of limestone seen in the burn suggest that this coal is overlain by a limestone not visible in place—No. 2, or North Greens Limestone. A limestone laid bare during the building of the school at the roadside, 100 yds. to the west, may represent either a higher bed or a repetition of the North Greens on the other side of the fold. Between this point and the Nine Mile Burn Inn the Carbeni- ferous Limestone is cut off by the Pentland fault, the intervening ground being obscured by drift. ; Between this section and the Cornton Burn, where these strata are next observed, the beds are interrupted by the fault or faults which run north-west and south-east through the Brunston Colliery. In the Cornton Burn the lowest limestone and the North Greens Coal are concealed by drift. The North Greens Limestone is here seen in two bands, separated by a few feet of shale. The lower bed is about 25 ft. in thickness, a very fossiliferous encrinital rock. Above the upper calcareous band, a good coal, 15 in., crops out in the burn, and, being correlated with the Vexhim Coal of Niddrie, fixes the position of the next succeeding limestone, a grey crystalline rock with large Encrinites, as * the Vexhim Limestone. There are no further exposures of the Lower Limestones between this point and Carsewell. L. W. H. MIDDLETON, ESPERSTON, TEMPLE AND MOUNT LOTHIAN AREA, The base of the lower group of Carboniferous limestones crosses the North Middleton Burn about 60 yds. below the bridge at North Middleton, and a good section of the lower portion of the lowest band of limestone is exposed along the stream between this point and the bridge at Guildie Howes. The bottom beds, which rest upon sandstone and dark shale with ironstone nodules, are composed of a dark, blue-grey, encrinital lime- stone. To this succeeds immediately above the cauld at the bridge. Lower Limestone Growp of Middleton Quarries. 187 a thick-bedded yellow-weathering limestone with a strong Lithostro- tion band. This coralline limestone is seen at short intervals along the stream to a point 60 to 70 yds. below the upper bridge. The. strata are dipping westwards across the burn at 10°, and though there is one break in the section where a limestone slightly different in character appears, it is probable that between the cauld and the upper bridge the stream is flowing over nearly the same beds, and that the whole thickness of limestone passed through in this section may not exceed 20 ft. The strike of the limestone in the stream carries it up to the old Middleton Quarry, at a slightly higher elevation on the south side of the road, where higher beds are exposed. The top of this quarry is a concretionary limestone which closely resembles the concre- tionary rock that forms the upper part of the section in the Catcune Quarry and of the middle limestone of the Tyne Water. Immediately below this concretionary limestone, which averages 15 ft. in thickness, is a band with large scattered Productus gwanteus followed by a shaly bed with large cup-corals. _ Below this come 12 ft. of flaggy limestone with shaly seams to the bottom of the quarry. A more complete section of these limestones, with the overlying strata, can be studied in the New Middleton Quarry, half a mile farther to the south. In the tramway cutting which leads into the quarry from the north, a thin limestone containing Producti, Encrinites, Syringopora, Alveolites and Cauda-galli markings is exposed at the bridge. This band can be correlated with a persistent thin limestone that has been traced between the middle and upper bands in the ground farther to the east. The complete section is as follows, in descending order :— Tramway Cutting. No. 3 | LIMESTONE a3 (seen) LIMESTONE. i sas a oe Pi Dark shale and thin coal q Yellow and white sandstone 2 Black shale with coaly seam 6 White fireclay .. se ae 2-3 Continued in Quarry Section. No. 2 Thick-bedded and concretionary LIMESTONE LIMESTONE with dark saiy| 16 (equivalent of partings F . SKATERAW LIMESTONE) Thin-bedded flaggy and faky 12-16 LIMESTONE Be 5 po apa and No. 1 Thick - bedded grey, yellow - LIMESTONE i weathering LIMESTONE with (equivalent o. cup-corals, Lithostrotion and . LONGCRAIG Encrinite bands : lowest layers 15-18 (bottom not seen) LIMESTONE). thinner with dark shaly partings ae si STONE now exposed in 50 Maximum thickness of a9) quarry 188 Carboniferous Limestone Series of Mid-Lothian Basin. The strata dip N.W. to N.N-W. at 10° to 15°, and the rock has been continuously quarried up the hill-slope to the south-east for a distance of 400 yds. The whole thickness of limestone represented in these workings must be nearly 100 ft. In the old quarries in the plantation ou the top of the hill the limestone is capped with a few feet of faky sandstone. The beds immediately beneath this cover differ somewhat in character from those at the top of the Middleton Quarry, and it is possible that the limestone of that quarry is here separated from a lower limestone by a few feet of non-calcareous sediment, which there is not sufficient evidence to trace for any distance further along the strike. A limestone with the characteristic concretionary top and Productus giganteus band of the Catcune and Middleton Quarries appears again in the North Middleton Burn a quarter of a mile to the south of Esperston. As this rock is followed up the stream it appears to pass continuously into a thick-bedded, yellow-weathering, encrinital limestone similar to that of the stream section above North Middleton, which is succeeded below by variegated sandstones and shales. The most obvious inference from the evidence afforded by the sections described above is, that, while the upper part of the Middleton Quarry represents the second limestone of the Tyne Water (Skateraw), and the limestones seen in the burn at North Middleton the lowest or Longeraig, in this particular area these two lower limestones have by the thinning out or complete dis- appearance of the intervening sediments nearly or entirely coalesced ; and that their combined thickness may here be considerably over 100 ft. It should be noted that in this part of the basin there is no evidence of any coal in the position of the North Greens seam, which on the west side lies between the two lower limestones— the Gilmerton and North Greens. Returning to the stream section at Esperston Farm, we find the same succession above the concretionary limestone as that seen in the tramway cutting. Immediately above the farm, and again 300 yds. farther down, the stream is flowing over a gentle dip slope of the third limestone with Cauda- galli, described in a former paragraph. Above this limestone in the stream bank is seen a fireclay and 16 to 18 in. splint coal (Vexhim Coal position), which is immediately followed by the base of the highest or Esperston Limestone. The Esperston Limestone is well displayed in the large quarries which extend for half a mile south-west from the Arniston Limeworks, and are at the present time extensively wrought for building and agricultural purposes. The section seen in the southern working face is as follows :— Ft. Yellow, brown-weathering sandstone .. 46 & .:|Yellow and dark shales- ‘2 &)Hard compact evenly-bedded blue), BS $\ LIMESTONE, in beds 1 to 2 ft. 20 C|_ thick, but thicker towards base ‘(bottom not seen in quarry) Thin shaly partings .. Lower Limestone Growp of Esperston. 189 The characteristic fossils of the upper part of this limestone are, Pinna flabelliformis, P. mutica, Spirifer trigonalis, Productus punctatus, Bellerophon, Syringopora, Cauda-gaili markings. The beds are lying at a very low angle, and sometimes appear to be almost flat, and the same limestone again appears in the bank on the north side of the deep valley below the old limekilns. In the area to the west of Esperston, along the southern margin of this Map, it has been found impossible, on account of the heavy covering of glacial deposits, to separate the different limestones of this group. The area tinted with the limestone colour represents the calcareous group as a whole, and does not imply that all the ground thus coloured is occupied by solid limestone. ___ The limestone exposed in the bank of Rosebery Reservoir (South Esk) at low water is probably the lowest bed, representing the rock of Middleton Quarry. It is overlain by sandstone, ‘fireclay and a thin coal. This coal was at one time wrought at Fountainside, but was found to be not continuous owing to the underlying and over- lying limestones coming together. L. W. The top of the next higher limestone is seen in the bed of the South Esk just below the outfall of the Rosebery Reservoir. It probably represents the limestone quarried at Esperston and Lime- stone No. 3 of Tyne Water. Some distance above it there is a thin calcareous band, passing in places into a fossiliferous. limestone, believed to be the representative of the limestone which was struck at the bottom of No. 17 bore of the Arniston Coal Company, where it had a coal with “parrot” close above it.. This thin limestone is well seen in the South Esk above Temple, and also as an inlier in the bed of the river between Temple and the junction of the South Esk with Redside Burn. The section below this thin limestone is somewhat as follows :— Ft. In. Shale .. im BS ois ee i - 10 0 CoaL.. = i ag ad -. from 9 in. to 0 6 Shale .. ei a5 ei a3 bs . 4 0 ‘CoaL.. ie a i - O 6 Dark shale and ganister 0 Thick red speckled sandstone with dark shale and 0 flaggy sandstone .. .. from 30 ft. to 35 LIMESTONE (Esperston) is An increase in the thickness of the beds takes place where the lime- stones mantle on the north and east round the Lower Silurian rocks, a small portion of which project into this Sheet near Venture Fair. These limestones were at one time extensively wrought in the neighbourhood of Mount Lothian, and also at the Side Lime- works near Fountainside, where the following section, now much obscured, was exposed :— Ft. Sandstone Concretionary LIMESTONE bands ~ LIMESTONE . Caleareous shale ie ds ga A LIMESTONE. es urs Sh na ae co a A -T 190 Carboniferous Limestone Series of Mid-Lothian Basin. The rock quarried at Hillhead and Fountainbridge (Sheet 24) is probably the lowest bed of the series. A thick limestone with a concretionary top, which may be correlated with the Upper Middleton or Catcune band, is seen at several places along the line of outcrop between Rosebery Reservoir and Mount Lothian, and has been wrought at the Fullarton Quarries, where the section shows— Ft. 1, Concretionary flaggy grey LIMESTONE with shaly partings .. 3 a as a -. 16-20 2, Hard grey encrinite LIMusToNE in thick beds (worked by amine) .. 4 ad ie 16 (bottom not seen) The limestone contains Saccamina cartert, Crinoids, Fenestella and corals, Productus longispinus, P. punctatus, Spirifer, etc. The dip is north-east at 8° to 10°. In the old quarries at Mount Lothian, now almost entirely grassed over, a hard grey encrinital limestone is seen, the beds lying almost flat or dipping N.N.E. at low angles. They probably re- present the lower beds of the Fullarton section, the whole of the intervening ground being presumably occupied by limestone. There is sufficient evidence immediately to the west of Mount Lothian to differentiate two limestone outcrops, separated by a belt of sandstone. At Herbershaw the limestones are finally cut off on the west by the fault which forms the eastern boundary of the basin in the ground to the south. The extension of this fault into the present area has been proved in the bores put down in the neigh- bourhood of Venture Fair. The limestones reappear on the west side of the fault between Venture Fair and Mosshouses, where they were formerly worked, but are now no longer visible. The evidence obtained in the ground farther to the south, a short distance beyond the limits of this Map (in Sheet 24), shows a certain amount of change in the sedimentation of the Lower Lime- stone group. There is, indeed, a general resemblance in character between the second or higher limestone in the south-east part of the basin and that of the Middleton Quarry; but with regard to fossil contents, aud, in the case of the other limestones, to lithological characters, it is no longer possible to correlate them with any certainty with the limestones on the east side of the area. The third or highest limestone does not appear to be always present, and where it occurs is of variable thickness, never exceeding 4 or 5 ft., and different in character from the Esperston Limestone. There seems to be more aftinity between these limestones and those on the west side of the basin already described. L. W. H. TYNE WATER AND GORE WATER AREA. Owing to the low angle of dip—in a general north-westerly direction—the lower limestones and the beds between them extend in the Tyne Water over a considerable distance—from Ford (Sheet 33) to Crichton Castle, near the head of the Tyne. The same limestones continue south-west and cross the Gore Water between Fushiebridge and Borthwick, but owing to the covering of drift they are only seen Lower Limestone Growp of Tyne Water and Vogrie Burn. 191 in one or two places outside the Tyne valley. From the exposures in the Tyne valley and in the Vogrie burn the following generalised section, in descending order, has been constructed :— Ft. In, Parrot CoaL— Yellow sandstone. Bs 3 .. 10 0 Black and blue shale * ‘(blaes) ie 6 0 Well-bedded rather calmy LIMESTONE with few crinoids and flattened oval concretions. Seen in Vogrie burn and quarry at Ford.. 18 0 Black and blue shale and white and yellow sandstones .. -. 20 0 Very ferruginous LIMESTONE, ‘with encrinites 1. 1 0 Sandy blue shale and hard sandstone = - 10 0 Impure dark-blue LIMESTONE "perhaps 5 0 Sandstone, shale and hard white ‘ganister with thin CoaL .. . perha: a 10 0 Ferruginous LIMESTONE with Syringopora an Cauda-gallr . 0 Alternating thin yellow sandstone and “ inky ” shale, with fireclay and a 1-ft. coal. Seen in quarry at Currie Lee “ is ae . 15 0 Hard LIMESTONE in two beds 8 0 LIMESTONE full of black concretions, probably pyritous, and with many fossils, including Pinna, Spirifer, 196 Carboniferous Limestone Series of Mid-Lothian Basin. the following general section gives the local names and thicknesses of the coals and of the intermediate strata :-— Ft. In. Fuex Coat... bx oe va ae -. 4 0 Intermediate strata ae a = se .. 380 O LaveERock Coau a ais ws a ae . 38 O Intermediate strata st ee it tes .. 24 40 Great Seam Coat .. ee a x - . 8 O Intermediate strata a as 2 ae .. 86 0 STAIRHEAD CoaL Ze a ee = ee . 4 6 Intermediate strata ts es ee is .. 60 0 GILLESPIE CoaL ‘ oa ae eh ei . 4 6 Intermediate strata ee we Ss ei .. 142 O Litre GILLESPIE CoaL Pe a2 ia ix a 2 0 Intermediate strata ae es re 2 .. 80 0 Biack CHAPEL CoaL.. as es Ga ws a » 6 Intermediate strata Se ste ae a4 .. 60 0 StTrIng1E Coat. Be a ee os « <8 0 Intermediate strata a Ks ed ats .. 80 =O Littie Spiint Coat . Bb A aes 2 ay & 0 Intermediate strata ce ifs es Oe .. 60 O Bie Spiint Coan aS is a vs as . 4 °0 Intermediate strata a as aus des .. 60 O Rea Corsi or Stony Coan 8 a8 ig - 5 O Intermediate strata ae dy oe s .. 150 O Coat .. ai fs a os te 2h 0 Intermediate strata se at a 343 . 78 O CaRLETON CoaL od 28 me is fs . 5 6 Intermediate strata oe 2 a oe .. 54° 0 Rover Coat .. on sie ae a s 8 9 Intermediate strata ose a a Ss .. 80 #O Buus Coat... es be : . 38 9 Total thickness .. 909 6 At Niddrie the thickness between the Great Seam and the Index Limestone is about 130 ft. The section on the west side of the now disused Joppa Quarries is as follows, in descending order:— , Fr. In. Black papery shales 2 0 CoaL .. is 0 6 Dark fireclay 0 8 Sandy firecla; 1 6 Nodular fireclay .. 1 8 Grit, flaggy at bottom 5 66 Grey shale . 3. 66 Flags i 1 0 Grey shales 2 8 Coan... 1 0 Flags and grey shales 5 60 Coat, Sparkes ws 2 4 Sandy hes 2 4 Nodular firec. ar 6 0 CoaL_.. 05 3 0 Fireclay 0 6 Grit 1 0 8 0 Massive grit The above beds are dipping about 61° to the east, but allowance for this has been made in estimating the thicknesses. The following section is recorded from a crosscut (belonging to Edge Coal Group of Niddrie. . 197 the Niddrie Collieries) situated just south of Brunstane Burn—the same crosscut which furnished the section of the Lower Limestone group :— Section of Part of the Edge Coal Group in the Niddrie Collierces. GILLESPIE COAL. Fakes ; Sandstone. . Fakes ‘ Sandstone. . Blaes Sandstone. . Blaes Sandstone. . Blaes Sandstone. . Blaes LittLe GILLESPIE Coat Fireclay Sandstone. . Faky blaes ; oe ae wes CHAPEL or Coan CorBIE CRaIG.. Fakes Blaes Sandstone. . Blaes, soft Srinkie Coa... Sandstone. . Blaes ‘ Littie SPLINT Coat .. Sandstone. . Fakes Sandstone. . Blaes Sandstone. . PEACOCETAIL (Bra SPLINT) Coan Fireclay i Sandstone. . Blaes Sandstone. . Blaes Cony, nen | REAL CoRBIE rv STONY re J oF Stow Fakes Sandstone. . Blaes Sandstone. . Fount Coat... Sandstone. . Fakes Sandstone. . Fakes Sandstone. . é Fireclay and blaes Sandstone. . _ Blaes with rib.of ‘day Sandstone. . 4 Blaes Carry forward Ft, 8 3 4 16 11 38 a owe es In. 2 3 11 e Ore aT OD — 5 7 4 ll 2 0 1 8 6 7 8 1 2 0 1 6 2 0 16 10 2 11 14. 9 1 5 2 8 9 10 6 2 1 10 3. («8 12 #4 5 9 2 6 220 «2 4 0 3 61 34. («6 4 11 9 10 18 11 2 6 1 5 1 5 18 1 66 5 8 2 40 2 2 0 8 2 4 11 15 #7 8 2 1 8 6 2 28 «8 18 1 60 8 15 7 . 666 9 198 Carboniferous Limestone Series of Mid-Lothian Basin. ; Ft. In. Brought forward .. 666 9. CARLETON CoAL ie <4 ee ay. 8 20) Blaes 9 10 Coan... ‘i a ba a a ae oe 1 C38 Sandstone ss Ee “4 ‘a ike .. 13 11 Blaes 4 11 Coan 1. 8 Fireclay 4 11 CoaL.. is a a oa ie iis ae 1 6 Blaes - wis ae - i ee ; 27 0 Sandstone. . oe te cp a bas .. 10 7 Blaes* .. Se 23 ss be aa we SS 6 Sandstone. . ad oa ae es eo gies DS 4. Faky blaes on ~ 28 np a . «87 O56 LIMESTONE. 827 0 The thin coals beneath the Carleton were not named in this account of the crosscut, and the strata beneath the Carleton appear to be very variable, for Mr. Martin gives the following section from No, 15 Pit, Niddrie — Section in No. 15 Pit, N ddrie. Ft, In, CaRLETON CoaL a ae x ok, si . 4 10 Strata a ee i Bs 8 ss .. 20 0 CanpDLu Coa. . ia os a ae ee pe Ds 20 Strata ea a8 a eo An .. 380 0 BLACKBAND IRonsToNnE acs as ane “aha tie QP -O Strata Ses a8 oe =i fe te ». 10 O BiuE Coan .. ne oe ae si ad ca 2 JO It will be seen that 300 ft. of strata separate.the Carleton from the next coal of good quality above it, namely, the Stony or Real Corbie. In this interval, a little farther south, we find the Corbie Craig of Gilmerton, which is the best-known coal in the south- western portion of the basin. At Niddrie, parrot is found in the Great Seam and the Stairhead—both in the upper portion of the series—and in the Candle Coal—in the lower portion—but in none of the intermediate seams. The parrot of the Great Seam is the best of those wrought at Niddrie, and Mr. R. W. Dron + has shown that it diminishes in thickness towards Joppa and Gilmerton. The section of this seam at Niddrie is as follows : {— oe Ft, In Coat, unworked .. Ps as ze ai 4in.to 0 9 CANNEL or GAS CoaL .. an bg .. 1fti2imto 2 6 TRONSTONE a ie ie ai ne 4in,to 0 8 Pett or Crow Coat... oe a we 3in.to 0 9 CoaL ie ie .. lft.2in.to 1 6 Daugh | or Blae Holing a “a a din.to 1 8 Borrom Coa, unworked ea ie .. 2ft.6in. to 4 0 * A dolerite dyke crossed the section between this and the overlying bed. + Op. cit. p. 225. i: Martin, “First Report of the Royal Commission on Coal Supplies,” 1903, vol. i, 'p. 79. Edge Coal Group of Niddrie and Gilmerton. 199 A thin ironstone occurs with the Stairhead parrot also, and both the Great Seam ironstone and the Stairhead ironstone are wrought at the same time as the coal. The section of the Stairhead seam at Niddrie is given below : *— Sream Coan STAIRHEAD CANNEL BLAcKBAND IRONSTONE.. a BLACKBAND [RONSTONE (infertor) ‘ RoveH Coat (steam) .. a ae oe oe oe Hoon ds bo _ De oD Qs The only exposure of the group between Joppa Quarry and Drum is to the east of Niddrie Mill, in an old quarry where a coal is exposed, which, though only 18 in. thick, appears from its position and the associated rocks to represent the Peacocktail of Niddrie. A little to the south, in a crosscut from No. 13 Niddrie Pit, a shale containing Zingwla was found. It lay about half-way between the Stinkie and the Black Chapel Coals, and seems, therefore, to be on a higher horizon than the shale, recorded by Dr. Traquairt as containing Zingula at Loanhead, which overlies the No..1 Iron- stone of that colliery. Dr. Traquair also refers to a band with Lingula squamiformis, which occurs probably about 10 ft. above the horizon of the North (Blue) Coal of Niddrie. Fish remains of the ordinary estuarine type, as Dr. Traquair points out, are associated with the Zingula, and it seems probable that this band represents the persistent seam of Lingula shale which overlies the Arniston Parrot in the south-eastern portion of the basin. At Drum, and again near Gilmerton, in the interval between the Great Seam and the Index (No. 4) Limestone, a soft yellow grit was formerly dug out to supply sand for stable yards. Between these two places the outcrops have been shifted by a fault, the course of which is only partially known, which acts as an important water barrier between the Niddrie and Gilmerton mines. The succession of the beds at Gilmerton is shown in the following ‘section, the original of which was taken from an old document in the possession of Sir David Baird, but the names of the coals, except that of the top seam, are taken from Mr. T. A. Tweedie’s Report on the Coal-field (1890). The strata above the Flex Coal are taken from an old plan by John Ainslie (1786) :— Ft. In INDEX LIMESTONE. Intermediate strata oes a 5s ae -. 28 6 BaxLew Coan ees $a oe re ats ace 20 Intermediate strata ie me bis se .. 86 0 Fuex Coan... i ae 3 i sy . 4 0 Intermediate strata a 2é bs a .. 60 O - RUMBOLD CoaL si ants ae om 6 we «2 80 Intermediate strata ee a8 ia ee wer 260 LavERocKk CoaL 2% i ie re A . 38 O Intermediate strata ig ag oe a .. 86 0 Great Seam Coat... oa an oe wee .. 10 0 Intermediate strata ak 5 ee Pe .. 18 #O *R. W. Dron, op. cit. p. 227. + “On the Distribution of Fossil Fish Remains in the Carboniferous Rocks of the Edinburgh District,” Trans. Roy. Soc. Edin., 1903, vol. xl. pt. iii. p. 694. 200 Carboniferous Limestone Series of Mid-Lothian Basin. Ft. In. STAIRHEAD CoaL ae 3.66 Intermediate strata 66 O GILLESPIE CoaL 2 3 «6 Intermediate strata 60 0O Briack CHAPEL CoaL 7 0 Intermediate strata 9 O PERPETUAL CoaL me 2 9 Intermediate strata 94 9 KITTLEPURSE CoaL si i — es xa 2 QD Intermediate strata ee - 6 ‘i .. 120 0 STINKIE CoaL.. £7 i = at me war 74, 20 Intermediate strata se ee as us i GRAS 10 Roveu Coan .. ee ss Ks ds see 8 Intermediate strata a és es is .. 114 #O Guass Coat .. 0 oe ae a3 . 38 4 Intermediate strata i Se ae a .. 50 O Parrot or Stony Coan ets aa i ay . 38 9 Intermediate strata es se .. 60 O CorBIE Craig Coat (with parting). 3 a asa 0 Intermediate strata és as re . 48 0 PrEAcoOcETAIL CoaL .. ee ds = x . 4 0 Intermediate strata ans oa ie oe .. 54° 0 CaRLETON CoaL as fd as id do ge “Dd. 6 Intermediate strata ote ws 2 Se .. 84 O Buvur Coat... bea te oe ee oie. wats IO Intermediate strata os ee 25 es .. 90 O LIMESTONE. It will be noticed that no coal under two feet thick is recorded in the above section, and that the total thickness of the coal specified is 80 ft. 3 in. It is not certain that the Black Chapel Seam of Gilmerton is on exactly the same horizon as the coal with the same name at Niddrie. In addition to the Great Seam and the Stairhead, three coals occupying a central position in the Gilmerton section contain parrot, namely the Kittlepurse, the Stony and the Corbie Craig. From the imperfect record of the section which now remains it is im- possible to say whether the Loanhead ironstones are represented at Gilmerton or not. Between Niddrie and Loanhead the Stair- head is distinguished by the possession of a very good roof, so that it is specially adapted to form positions for permanent inclines. It acquired its name in fact from being often used for stairways before the days of mechanical haulage. W. G., EB. B LOANHEAD AND MAURICEWOOD FIELDS. The dip workings and the cross-cut mines in the Loanhead and Burghlee Collieries show that the Edge Coals and the Upper Lime- stone group dip to the south-east at high angles. At Burghlee Pit the Great Seam has been worked to a depth of 1578 ft. (vertical) or 1860 ft. along the incline, with an average inclina- tion of 58° to the south-east. At the bottom of the mine the dip decreases to 7° or 5° and continues at this low inclination as far as the coal has been worked, for a distance of 1200 ft. to the east. This change from the high angle on.the west side of the basin to the comparatively flat angles of the central area, though sharp, is not accompanied by any line of dislocation. Edge Coal Group of Mauricewood. 201 At Roslyn Colliery and Glencorse Burn the Edge Coals dip to the south-east. The underground workings at Greenlaw, together with the sections in the Glencorse Burn at Auchindinny and in the river Esk half a mile above the Roslin Powder Mills, show that the Edge Coals, still dipping to south-east, flatten out for a short distance, and then rise gently to the south-east (see Fig. 18), This change of inclination takes place nearer the surface than at Loanhead, which is quite in accordance with the fact that the Mid- Lothian basin becomes shal- lower towards the south. The accompany- ing section (Fig. 18) has been drawn from Mauricewood House to Bore No. 28, near Loanstone, to illustrate the folding of the strata in that part of the field. The old iron- stone workings of the Mauricewood pit * show that the Edge Coals dip down sharply to — south-east for some little distance be- low sea-level, and then suddenly be- come flat, After slight undulations for a considerable distance near Hast- field the dip proved underground changes to the north-west, and the crest of an . anti- Fic. 18.—Section from Mauricewood House to Loanstone, clinal fold is pierced showing folding of the Carboniferous Limestone Series, by Bore No. 29 (see Fig. 18), on the south-east side of which the beds rise again towards the south-east, so that the Castlecary Limestone crops out at Loanstone. From Mauricewood to Cuiken Burn the ground is faulted and ? MAURICEWOOD HO. 3UNW!1=SAHINIE FIVIS 7v02 —) boar /) NOINN = / ROAD BORE N° 49 BORE N° 60 \ EASTFIELD FAULT BORE N229 R.ESK or 19 TWWOD HLYON \-----T>> TE rITTrU TWO? IJivw? Wewvo0I LS7 NOLYIWT LOANSTONE LS7 SNIFTUXOD HL20N BORE N°? 28 * In the Mauricewood pit the lower coals near the surface become nearly vertical and this is the beginning of the reversal of the strata in the vicinity of the Pentland fault seen in the Nine Mile Burn. 202 Carboniferous Limestone Series of Mid-Lothian Basin. disturbed, and the crops, as laid down on the map, are chiefly calcu- lated and protracted from boring information. Several dislocations were supposed to traverse that portion of the Edge Coals which lies to the south-west of Laverock Hall, Gilmerton, and as a large east and west fault has been proved in the Burdiehouse Limestone Mine (60 fms. downthrow to the north) a curved liné has been drawn from near Long Loan by Wester Melville to connect it with the known position of the Sheriffhall fault to the east. ~~ As regards the tract between this fault and the Edgefield dis- location, very little mining information is available, but the coals-are believed to be there inclined at a high angle to the south-east, and in some cases may be vertical. The position of the Flex Coal has been got in a pit 26 fms. in depth, situated 500 yds. to the west of Wester Melville. From this point to the proved crop of the Fells Shale the strata would require to be nearly vertical in order to allow all the beds to crop out. The strata in the cross-cut mines in the Burghlee and Loanhead pits have now been measured, and the details are Eee in the subjoined table :— Section of Edge Coals and Intermediate Strata at Loanhead. Ft. In. Ft. In. LIMESTONE, INDEX. ; Strata se ws os a Pa 102 0 Coat, Fimx .. ais is ai ia we DO Strata a ee 72 O No. 3 IRonstrone or RUMBLES PARROT sg - 4 6 Strata 12 «#O CoaL, GREAT SEAM 8 O Strata ; 84 6 5) STAIRHEAD a its as x «x 8 4: Strata ; Se ne 22 #9 No. 2 Inonstons or CHARLIES Coa Pe ge HOO AE Le oa Strata as Oe es aks ee 24 O Coal, Morrats sre a a: 2 © , Strata as a ie bye 9 2 » GILLESPIE 0 a us ..3ftto 8 4 Strata 08 so ie 49 1 » BULACKCHAPEL .. 5 2 3 Strata iis is its : 4 0 », PERPETUAL or Canpatin se 5in.to 2 2 Strata ~ ad a Sas 6l 4 » KITTLEPURSE .. ee .. 2ft.8in. to 3 0 Strata aA a ae ae a 33- 6 5) STINKIE or PEACOCK .. aus ais ». 8 10 “ Strata ts sr ist a ox 51 6 » RovuGH .. es as .. 1ft.9in.to 3 0 / Strata ait io as ie 40 7 GLASS... ra as cast = *2it.to 8 6 Strata . ace eh a 16 «5 No. 1 Ironstone 3 6 - Strata wi 6 ste ax 7 6 Coat, BRowns as ie o. 24.-6in. to 1 07 Strita sf ae tia ace ~ 100 11 Rover .. id snd i ie ve QO 7 Strata ate ae ie 14 8 », Stony or PARRot AND. Rouen es - 5 3% Strata os ine ae se i 10 0 Carry forward .. 60 6 665 Il Edge Coal Group of Loanhead. 208 Ft, In. Ft. In. et forward .. 60 5 665 11 Coat, Horgs .. ie . .. lft.8in.to 2 O Strata .. fe its ae 14° #7 » BEATTIE .. st ae /1ft.l0in.to 3 11 Strata . ; . at 20 O », CORBIE ORale or Corsie Rover oe we AL $3 » SPLINT .. pes ee si sx 4 2 Strata. : a is aa 107 10 ee AnpreEws or Lirrne SpLint ..2t.10in.to 5 10 Strata . “ ie 4 ms ne 48 8 » SOUTH or CARLETON sé ., 4ft.2in.to 5 8 Strata... Zs oh ss 5 sa 24 0 eo TED ace be a x8 ne wo dt 4 4 ' Strata. , a8 ate 17.1 » LITTLE SpLinty or CANNEL Fir - eg ab) Strata . ood ea svg i ou ; a) » NoRtTH or Buux a oe as ..3ft.to 4 6 Strata. . te sd we a es 15 O LIMESTONE, 93 11 914 10 The Iowest seam in the above vertical section—the North Coal—is separated, in the Bilston Burn, by 15 ft. of yellow sandstone and blaes from the 20-in. limestone which there forms the top of the Lower Limestone group. This seam is the equivalent of the Blue Coal of Gilmerton. In the latter field it is 7 ft. thick; at the Edgefield fault, 4 ft. 6 in.; and at Loanhead, 4 ft.; while at the Dryden March it is reduced to 2 ft. 11lin. It is a rough coal mixed with splint of superior quality. The upper portion is sold as house- hold coal. The sections at Dryden March and Loanhead are given below :-— Ft. In, ( Roof, blaes. SpLint CoaL a is ae ie 2 20 FREE, is ae aye . O11 At Dryden March. RES 2 11 Pavement, sandstone .. - O ll Ft, In ( Roof, blaes. Fre Coan 0 6 SPLINT ,, si ae A - O 9 FREE ,, = ue Gs .— O 4 SPLINT ,, 5 if a 0 9 At Loanhead.{ Sorr Frre Coat . 1 6 Daugh 0 2 4 0 L Pavement, sandstone .. ew The Little Splinty or Cannel Fir Coal, 1 ft. 2 in, thick, lies immediately above the North Coal, being separated from it by thin bands ranging from 1 ft, 9 in, to 2 ft. 3 in. in thickness. It isa hard splint coal of very superior quality, but has never been wrought. The roof is composed of bands mixed with blaes, and the pavement is a soft fireclay. The Little Coal, about 1 ft, 4 in. thick, is a soft 204 Carboniferous Limestone Series of Mid-Lothian Basin. rough coal mixed with splint of good quality, which has never been worked. The South Coal varies in thickness, becoming thinner towards the south-west. It is a hard, rough, second-class house coal, the upper portion being splinty, and the lower very soft. It is the equivalent of the Carlton Coal in the Gilmerton field, and shows the following sections at Dryden and Loanhead :— Ft. In. Ft. In. Roof, blaes. Roof, blaes, InrerionCoat.. 1 0 InFERIOR Coat 1 0 Hard Fireclay 0 4° Parting 0 2 At Dryden.4 Sprint Coan 2 10 | Ae Tonnes Sumy CoaL ; in —_—- ‘| FREE Coau 4 2) ae Pavement, blaes. 5 8 Pavement, fakes. The Andrews or Little Splint Coal varies from 2 ft. 10 in. to 5 ft. 10 in, according to the thickness of the stone interleaved with it. The lower portion is a soft rough coal, and the top coal is harder but full of iron pyrites. In working, it breaks up into dress as the holing has to be done in the bottom bed. It has only been wrought to a limited extent for steam purposes, and has the following section :— Roof, blaes. Ft. In. Sort Coat... 2 6 Black ston oe a oe oh sx “Ll -8 Coan sa ect Sed als “ om ae PES: 5 10 Pavement, fakes. The Corbie Splint and Corbie Craig Coals display the following sequence at Loanhead :— yy st Roof, fakes with ribs of blaes. Sciurty Coat, inferior FREE a 3 SPLINT _,, FREE 5) ScLurty ,, SPLINTY ,, {Fase 6 ScLurTy ,, Corbie Craig, 4 ft. 11 in. inferior Corbie Splint, 4 ft. 2 in. ~ 24 SSannmwar p inferior © | Orr OFOrre Pavement, soft fireclay. The lower seam or Corbie Splint is a superior splint coal, varying in thickness; the upper seam or Corbie Craig is a firm rough coal of good quality. Both become thinner in a south-west direction towards Dryden, the Corbie Splint being reduced to 2 ft. 9 in. at Dryden, while the Corbie Craig, which has a thickness of 4 ft. 11 in. at Loanhead, diminishes to 4 ft. at Dryden. At Loanhead the two coals come together, but in some portions of this field they are separated by 10 to 18 ft. of strata. The pavement of the Corbie. Splint consists in places of bands and fireclay and in others of very coarse sandstone. The strata separating the Beattie Coal from the Corbie Craig are Edge Coal Group of Loanhead. 205 thicker at Loanhead than towards Dryden. At Dryden March, as shown in the following section, they consist merely of 30 in. of blaes, which, together with the Beattie Coal, 2 ft. 7 in. thick, is left as a roof to the Corbie Craig :— eS 5B EP AROnDoOwon-t BrEattiz CoaL Blaes .. 3 CorBIE CRAIG Coan option at . oe Dryden March. Bree Corbie Splint, {Free Coan : FREE, es 2ft.9in. (gororry ? inferior Fireclay HOooOHMaonwwed _ A reduction of thickness towards the south-west has also been observed in the Beattie Coal. At Loanhead the top portion of this seam is a firm rough coal of good quality; the remainder rather soft; both being sold as household coal. The bottom sclutty portion varies from 9 to 15 in. in the mine, and, when the stones are removed, is used for steam purposes. The Hopes Coal is a variable rough seam and has only been partially wrought. It has the following sections :— Ft. In. Ft. In. Roof, sandstone and blaes, WILp Parrot Coat Be a eu .. O 4and0 10 Coa mi did = Pe ik eed @ ds 2 i 8 2 O The Stony or Parrot and Rough Coal is separated from the Hopes Seam by strata varying in thickness from 10 to 31 ft. The Parrot on top is poor in quality and not always present. The seam, which is all exhausted down to the Mavisbank day-level, displays the following sections :— Ft. In. Ft. In, Roof, black blaes. Roof, blaes. Parrot CoaL 12 Parrot Coan .. 0 4 Fireclay 0 14 WILD PaRrRor Coa 1 2 Coan 0 4 Stone 0 5 Batt IRonstonzs 0 4 Coan 2 5 Coan . 1 Qg Sandstone .. 0 14 5 3} Coan... eae 2 Pavement, blaes. Sandstone .. 0 14 CoaL 10 4 6 Pavement, sandstone. The blaes roof is very brittle and the Ironstone and Parrot are left to support it. The seam below is a rather soft rough coal of fair quality, which is sold for household purposes. The Rough Coal above the Stony Seam is a coarse rough coal which has not been wrought. The Browns Coal varies in thickness from 1 ft. 7 in. to 2 ft. 6 in., and is believed to be entire throughout this coal-field, 206 Carboniferous Limestone Series of Mid-Lothian Basin. The No. 1 Ironstone,—an important fossiliferous horizon,— furnishes the sections given below :— Roof, blaes. Ft.. In. CLAYBAND IRONSTONE .. as at ee . 0 5 Wiip Parrot Coan 10 Dryden) B. B. IRoNSTONE .. O 8} March. | B. B. ss 0 5 Daua# CoaL 0 3 Pavement, hard blaes. co We bs Roof, blaes. TRoNSTONE ‘ CLAYBAND [RONSTONE Witp Parrot Coan ‘ 5 » With IRow STONE. Pavement, fireclay. Loanhead. '. . \ " Roof, blaes. Tor TRONSTONE ee Light band (parrot and ironstone of no value) | Witp Parrot Coat, top band ba $6 » bottom band B. B. IRONSTONE . Bortom B. B. TRONSTONE. Pavement, sandy fakes. \ 3°47 occoooood typ rHuoom & Loanhead. | It is overlain by a Lingula shale, and both have yielded fish remains which have been determined by Dr. Traquair,* but the zone is not so prolific as the Rumbles Ironstone to be described presently. ' The Glass Coal is a hard rough coal, ribbed with splint, is of a good quality and shows the following sequence :— Roof, sandstone and blaes. Ft. In. Free Coat .. 2 4 Daugh Coal. . 01 FREE COAL .. 14 Pavement, faky blaes. sais 3.6 The Rough Coal above the Glass varies in thickness from 1 ft. 9 in. to 3 ft., and is a bard rough coal with a bad roof and pave- ment. It is believed to be unwrought throughout this coal-field. The roof coal of the Stinkie or Peacock Seam is a fine splint. The under coal varies from 3 ft. to 4 ft. 2 in. in thickness and is a rough free coal full of iron pyrites—suitable only for steam puryoses. The sections at Dryden and Loanhead are given below :— Ft. In. Ft. In. Roof, blaes. Roof, blaes. Coat .. ee 4 OF I Fins Sprint Coan O 10 Sprint Coan - 1 0 Loanhead.{ Coan ce ee BIO Dryden. RoueH __,, .2 6 Pavement, fireclay. —— Fireclay ; ~O 3 10 Pavement, hard blaes, —— : 3.8 * Trans. Roy. Soc. Edin., 1903, vol. xl. plate iii. p. 695. Edge Coal Group of Loanhead. 207 The Kittlepurse Coal is ribbed with splint of a superior quality, is sold as a good household coal, and has the following section :— Roof, blaes. Ft. In, WILD Parrot CoaL I 22 Coan 1 6 2 8 Pavement, fireclay. The Perpetual or Calpatie Coal is of variable thickness, sometimes amounting to 2ft.2 in. Itis a firm rough coal of inferior quality, and has been wrought only to a limited extent in this field. In part of the Burghlee workings it shows the sequence given below :— Roof, blaes, Ft. In. TRONSTONE ve a eis us wid we sa OF 8 Blaes. . a <4 ts a as at . 0 6 Coan ie a i ne at a ss . O 5F 1 2} Pavement, fireclay. The Blackchapel Seam is a thick, soft, free coal of poor quality, with ribs of stone and iron pyrites, suitable only for steam purposes. It shows the following composition :— Roof, sandstone. Ft. In. Coan ee ie a 2 ay dy og .. 3 5 Fireclay fs 25 aa is 3 a . O 5 CoaL Ma 5 ‘3 i A st ans . O 4 Parting ie is a hs ae ai -. O O§ Coan oe in as os #3 Po ss oa OT] 52 Pavement, fireclay. The Gillespie Coal, occasionally 5 ft. thick, is a soft rough coal of good or medium quality and used chiefly for steam purposes. It furnishes the sequence given below :— Roof, sandstone. Ft. In. Shale ee ss ee ss ia Hs .. 010 CoaL an wis ae ts ai a a .. 8 0 3 10 Pavement, fireclay. The Moffats Coal, which varies in thickness from 9 in. up to 2 ft., is a good rich smithy coal with a soft blaes roof and fireclay pave- ment, but has not been wrought. Charlies Coal or No. 2 Ironstone displays the following sections :— Roof, black blaes. Ft. In. IRONSTONE .. ae Oo ol Black blaes 0 10 Gas Coan 0 10 IRONSTONE Ons) 2 6 Pavement, coaly sclit. 208 Carboniferous Limestone Series of Mid-Lothian Basin. Ft. In. Roof, sandstone. WILD Parrot CoAL .. a es 5 re . O 8 i. - Gorda oe ae, The Shc, ae. SOO Ironstone Banp_... 3 = ne = - O 4 Witp Parrot mixed with RoueH Coat and occasional TRoNSTONE 2 in, thick Pre ae Ls ww, O 9 2 7 The Parrot or Gas Coal in this seam was tried in 1849 at the Edinburgh Gas Works and was reported to be of inferior quality, probably because the coal had not been properly cleaned before it was sent to the Gas Works. The ironstone is of good quality. The Stairhead Coal is a rough coal of second-class quality with the following sequence :— Ft. In. Roof, sandstone. Coan 1 4 » DUFF 0 4 5 : 1 8 3.4 Pavement, sandstone. The Great Seam yields coals of good quality, the upper or splinty portion forming an excellent household coal. Three sections are given below :— Ft. In. Roof, black blaes. Coat, Craw 3 0 8 Blaes 0 9 Coa, SPLINTY 1 3 » FREE 0 2 » PARROT Oo 2 » FREE.. 2 0 % i Fireclay 0 38 % Coal, FREE 1 113 Fireclay 0 1 Coat, Grounp 1 6)! Fireclay 0 3 9 8} Ft. In. Ft. In. Roof. Banded roof. Fireclay.. O 5 Coat, Ribbed Splint 5 0 Coa... oe 4 10 Coat, RoveH se 6 Fireclay.. O 4 a Coat, Bottom 1 9 6 6 Fireclay.. 1 7 —_— 8 Ill No. 3 Ironstone or Rumbles Parrot or Ironstone and Gas Coal is 12 ft. above the Great Seam at Loanhead, but 18 ft. above that horizon at Dryden, where it was chiefly wrought for its excellent gas Edge Coal Group of Loanhead. 209 coal, which thins out to 2 in. to the east. At Dryden its composition is as follows :— Ft. lanl Bp Roof, blaes. Coat, Wi1tp Parrot IRONSTONE .. Coat, Gas .. IRONSTONE .. Hy onor al~rn0o At Loanhead the Rumbles Seam is a rich soft coal. The wild parrot in the centre varies from 4 to 10 in. in thickness and was sold with the coal, for which there was an excellent local demand. The sequence in one part of Loanhead is given below :— Ft. In Roof, blaes. Sort Coau .. e3 14 Coa, WILD Parrot a ae wih Re wa AO ») SOFT... we on re a 8 “a ve 3.0 Pavement, rock. On the west side of Loanhead the seam contains from 54 to 8 in. of excellent parrot and also 11 in. of free coal. As the holing is made in the 1 ft. 3 in. of coal, and the mined coal is shot down the steep spouts to the workings below, a large portion of the seam is reduced to small coal and dross. There the sequence is as follows :— Roof, blaes. Ft. In. Coat, WILD Parror 1 0 TRonsTONE 0 2 Coa, PaRRot O 8} 9) FREE 0 11 CoaL 1 3 Coal, FREE 0 4 4 4h Pavement, sandstone. The No. 3 Ironstone, separated by 12 ft. of strata from the Great Seam below, is especially noteworthy as the most productive fish bearing bed in the Lothians. Dr. Traquair,* who calls this band the Borough Lee or Loanhead Ironstone No. 2, has recorded 35 species from this locality. The Flex Seam is a good rough coal, and when separated from the Duff is sold as a good household coal similar in quality to the Great Seam. The following is a representative section :— Ft. Iv. Roof, sandstone. Coat, Durr .. £3 ay ai ‘i sed Ms sc OO 8 » RovuGH oe ree ava a ie a . 38 4 1 0 Pavement, soft fireclay. All the seams in the Loanhead field attain their maximum thickness and quality in the vicinity of the Edgefield faults. To * Trans, Roy. Soc. Edin., 1903, vol. xl. p. 696. 14 210 Carboniferous Limestone Series of Mid-Lothian Basin. the south-west they become thinner and of inferior quality, with the exception of the No. 3 Ironstone or Rumbles Parrot. Section of Hdge Coals and Intermediate Strata at Roslin. Ft. In. Ft. In. Coa, STAIRHEAD we Oe ae a 1 7 Strata .. Ee ie se i, 10 6 » CHARLIES ma oA ea Bs 1 6 Strata .. si sis ee ce 22 8 Ironstonz No. 2 ee Ha si zs 1 2 Strata .. ioe Coat, Morrats 0 10 Strata .. 19 0 », GILLESPIE 2 6 Strata .. as sx i id 48 10 » BUACKCHAPEL .. as zh os 2 6 Strata .. 83 «6 » KITTLEPURSE 0 Strata .. 47 9 », PEACOCK .. 3 69 Strata .. 73° 8 » Guass.. 2 6 Strata .. 49 2 » BROWNS .. 2 6 Strata .. 59 5 » STONY .. 3 0 Strata .. 49 2 » BEATTIE .. 1 6 » CORBIE CRAIG 4 6 Strata .. 8 i 0 » CoRBIE SPLINT .. 3. 4 33 2 467 9 =600 11 The details in the above section are taken partly from a shaft, 80 fms. deep, sunk at the new colliery at Roslin to about 5 fms. below the Peacock Coal. The rest of the section has been obtained from two stone mines, one driven towards the Great Seam and the other in the direction of the North Coal. In the area between Loanhead and Penicuik the thickest coal is that formed by the practical coalescence of the Beattie, Corbie Craig and Corbie Splint Coals. The section of these three seams in Roslin North Mine is as follows :— Ft. In. [RONSTONE a5 ag es 65 33 ge O28 Blae a ns or oi a na . OO 9 Coat, Brarriz ; 1 6 » CORBIE CRAIG .. 4 6 Blae 1 0 CoaL, SPLINT .. 1 6 ,» Rovee .. 1 10 11 3 This Roslin Pit is connected with the Burghlee and Loanhead workings by a continuous level road in the Peacock Seam, which also extends as far as the Edgefield fault, a distance of two miles. Between Loanhead and Roslin the strata between the top of the Edge Coal Group of Mauricewood. 211 Stairhead and the base of the Corbie Splint Coal diminish in thick- ness 24 per cent., and the coals and ironstones, 44 per cent., as shown by the following tables :— Loanhead Section. Roslin Section, Ft. In. Ft. In. Coats, total thickness ee so BY JI 324 Strata .. ae a .. 480 0 467 9 5387 11 5001 Between Roslin Pit and Gowklie Moss, a fault shifts the strata on the south-west side some distance to the north-west, from which dislocation to Greenlaw no mining operations have been carried on since that area was first mapped by the Geological Survey. In the Mauricewood Colliery the following seams are worked, namely the Johnston, Union, Stairhead, Corbie Jewel and Corbie Splint, this field being separated from the Greenlaw workings by a fault with a downthrow to the south, amounting in places to 45 fms. but diminishing at the Mains to 25 fms. :— Section of Edge Coals and Intermediate Strata at Mauricewood. Ft. In. Ft. In. CoaL, JOHNSTONE... ha _ ax . 4+ 0 Strata ae a a ee 4 42 0 » WAVERLEY .. sie oe is ie UO 6 Strata es we a0 ab ing 15 0 » Unton (FLEx Coat of Loanhead) .. . 4 0 Strata = i ce os ee To 2 Strata a i se ie i 41 3 IRONSTONE .. ee ee a aS sa, “OL Strata su oe ag ie Bi 12 #9 B.B. IRonstonE 8 a ain he an 1 0 Strata ea oe ae 7 oe 1 8 Coat, GREAT SEAM .. i 24 si . 8 4 Strata ee he ee Ms 1 17. OO Strata ad <4 a as ea 1 Oo » STAIRHEAD.. a oa a sa 8 I Strata ze ae os ee as 4 10 as, Gs 4 e cs es a Bac. oie ca Strata hs es oe oe ie 24 5 5 te ea ee 1 6 Strata is na ne ia 15 O » GILLESPIE iss se a5 ie wa DS 136, Strata acs eee 8 et 361 » BLACKCHAPEL.. a ac ae pe LID Strata é 163 6 a? faal Se dag Ge toa. Oe ceils S2EAI2 Strata si 8 i es ia 17° (10 a Ge ea Ms Ge ee ARS Sees, ve SI Strata =e oy ee ee eg 173 » CORBIE JEWED.. 55 - a sc AD Strata ocd a a AG 53 10 3 5, CORBIE SPLINT es ae a we 2°36 Strata a ih a ea ia 68 10 Strata a3 bi ie aa hy 15 il Carry forward .. 45 8 511 9 212 Carboniferous Limestone Series of Mid-Lothian Basin. Ft. In. Ft. In. 3 Brought forward .. 45 8 511 9 CoaL, SouTH .. a 54 i od . 2 4 Strata ag ire si ae ae 21 5 » Norte .. a 63 = a . 2 4 Strata LIMESTONE, BILSTON BURN 50 4 533 2 _ The above section shows that the thinning of the coals and intermediate strata in a south-west direction already noticed between Loanhead and Roslin continues even in a greater degree towards Mauricewood. A comparison of the strata from the top of the Flex Coal to the base of the North Coal at Loanhead and Mauricewood proves that in the interval of three miles between these places the thickness of the strata exclusive of coals and ironstones has diminished 40 per cent. and the thickness of coals and ironstones combined, 53 per. cent., as shown in the following table :— Loanhead Mauricewood Section. Section. Ft. In. Ft. In. Coats and Ironstonss, total thickness .. 93 5 43 10 Intermediate strata 8 3% .. 797 10 476 2 891 3 520 O A careful analysis of the details of these two sections indicates that the strata, comprising 150 ft. of coarse sandstone and 9 ft. 4 in. of fireclay that lie between the Blackchapel and the next lowest coal shown in the Mauricewood section, must be the equivalents of the coal seams and associated strata, which, in the Loanhead section, come between the Blackchapel and the Stony Coals. Among these seams are the Kittlepurse, Peacock and Rough Coals. It is evident, therefore, that very different conditions of deposition must have prevailed in the Mauricewood area while these well-known coals were in process of formation between Loanhead and Roslin. J.8.G. W. PENICUIK FIELD. AREA SOUTH OF PENICUIK. The Edge Coals are not at present wrought anywhere within the limits of this Map to the south of Penicuik, but their position has been proved by a number of bores put down in different parts of the area to the south and south-west of Penicuik. The details of many of these bores have been kindly placed at our service by Mr. Gemmell, Mining Engineer. The highest of these coals, the Flex, which in this part of the basin lies about 20 ft. below the Index Limestone, crops out in the small burn 500 yds. north-east of Penicuik House. It appears again, together with two other coals, probably the Rumbles and Great Edge Coal Group South of Penicurk. 213 Seam, in the steep bank on the north side of the Esk. The seam 3 ft. thick, seen in the old quarry west of the pond, dipping south-east at 30° beneath a thick sandstone, is probably the former coal. A bore put down close to the saw mill gives a good section of these coals. The beds are dipping south at 60°, and owing to the high angle the thickness of the seams given in the bore journal, is exaggerated. The first coal got in the bore (the Flex) is in two beds, the upper 2 ft., the lower 3 ft. 3 in. (true thickness). The second seam —the Rumbles—is also split by an 8-in. fireclay into two beds, 1 ft. 10 in. and 7 to 12 in. respectively, in true thickness. The Great Seam, 29 fms. from the surface, is in two beds, 17 to 20 in. and 6 to 8 in., separated by 19 to 30 in. of stone. Between this point and the outcrop of the Index Limestone at Cornton, the beds are thrown into a series of gentle folds, and the thin coals of the Upper Limestone group seen in the Cornton Burn below the bridge at Cornton are lying in a series of shallow basins. It has not been found possible to identify or trace the outcrops of the two seams seen at intervals in this section, but it is probable that the Wood and South Parrot, both of the Upper Limestone group, may be represented. The Flex and Rumbles Coals appear in the Cornton Burn 100 yds. above Cornton, and their outcrops follow the course of the stream for some distance. Where they first cross the burn the beds are vertical, and, a short distance farther up, the dip is slightly inverted towards the north-west. The lower coals can be seen crossing the burn farther to the westward, where they have been identified successively as the Black- chapel, 16 in.; the Glass, 2 ft.; the Beattie, 10 in.; the Corbie Craig ; and the North and South. The position of some of these coals in the ground between the Cornton Burn and the Esk, has been approxi- mately fixed from their occurrence in the section of the Talla Water tunnel.* The entire series of the Edge Coals, from the Flex to the North and South, are found at the old Brunston Colliery, on the north side of the Esk, which was worked for many years, up till about the middle of the last century, by a day-level driven from the river bank. The Flex is here a soft dirty coal, 22 in. thick, The Rumbles averages 34 ft.,and a small area of it was worked for steam coal. The Great Seam is not more than a foot in thickness and was not found to be workable, but other seams lying beneath it were wrought to some extent. The first of these is the Stony Coal, of poor quality, about 3 ft. in thickness, divided into two beds by 20 in. of stone. The next seam is the Corbie Craig, the best coal of this part of the area, which also occurs in two beds separated by 12 to 20 in. of fire- clay. The top bed is a rough coal averaging 2 ft.; the lower gives 14 to 18 in. of good splint coal. The lowest coals, the North and South, were here regarded as forming a single seam, composed of a splint coal of 13 in., a hard “kingle,” 2 ft. 10 in. and a 20-in. coal below. The seam is hardly workable, but a small part of it has been wrought out. The following section gives the details of the succession and * Information kindly supplied by Messrs. Leslie & Reid, Engineers to the Edin- burgh and District Water Trust. 214 Carboniferous Limestone Series of Mid-Lothian Basin. thickness of the coals and intervening strata at the Brunston Colliery :— Section of the Hdge Coals at Brunston Colliery.* by oF . In. pe Oo LIMESTONE (No. 4) Sandstone Fuex Coan .. White fireclay RuMBOLDs (or RUMBLES) Coan Sandstone and fireclay .. Laveroce Coan Sandstone Coat .. : Sandstone. Coat—Great Seam Fireclay and ironstone balls STaAIRHEAD CoaL.. Fireclay and ironstone balls GILLESPIE CoaL Indurated clay CoaL, mixed with stone Sandstone. . Fireclay .. Sandstone Shale (blaes) Sprint Coa .. Shale (blaes) Gass Coau .. Indurated clay Stony Coan 5 se Coarse grey sandstone .. Horzs Coat .. vs Fireclay with ironstone balls .. Beattie Coan Sandstone and shale Fine white sandstone CoaL we a6 is ai Firetey| CorBIE CRAIG CoaL CoaL i sé za ee ww eo We oF ROWONHRWNOD et PRE OWFRNWOO maT bo WH DOTWOWRr WOM ee e H1oOownonorowownooce © oo DOE WORORFRDODOEFNNAYNKHYENOOrH w rg a A comparison of this section with that of Loanhead, 7 miles to the north-east, will show how greatly the beds have diminished, the total thickness of coal at Loanhead being over 80 ft., whereas at Brunston the same seams only amount to 27 ft.5 in. Again at Mauricewood, 3 miles farther to the north, the thicknesses of the Great Seam and Gillespie Coals are respectively 8 ft. 4 in. and 3ft. 1 in., while the same seams at Brunston measure 1$ to 1 ft. and 1 ft. 8 in. A similar thinning to the south is shown by the North Greens Coal (Lower Limestone group), which diminishes from 2 ft. in the Nine Mile Burn to a few inches or nothing at the south end of the basin. A large fault, 50 fms. wide and filled with broken rock, runs through the Brunston Colliery. Its direction is north-west and south-east at right angles to the strike of the strata, and the down- throw is to the north-east. It is not improbable that this may be * Communicated to Mr. Howell by Mr. J. Lawson, late manager of the Colliery. Edge Coal Growp of South of Penicuik. 215 two parallel faults, the rock being broken up between them. Two other faults interrupt the coals between Brunston and the Nine Mile Burn, both throwing the strata down on the north-east side.* The Rumbles can be traced along the steep bank beneath the sandstone quarries south of Brunston Colliery, and is seen again, together with the Flex, in the face of the large quarry at Marfield, where an excellent freestone is wrought at the present time. The section now exposed in the Marfield Quarry is as follows :— Ft. In. Sandstone. Blaes_ .. mi 6 0 Coat (FLEX), soft dirty 1 5 Blaes .. he 6 0 Coat.. 3 0 » SPLINT 0 10 RoMBLES, Blaes 1 6 Fireclay Oo 4 Coau.. ‘ 0 4 Shales .. i He os a 4 0 Thick yellow sandstone ae i 40 Oseen, Three coals, identified by Mr. Howell as the Beattie, Corbie Craig, and North and South, are seen inthe Nine Mile Burn dipping to the S.S.E, at 20° to 30°. Lower down, the burn is flowing over the thick yellow sandstone which underlies the Great Seam and Gillespie: Coals. The Great Seam and higher coals cross the Esk at Marfield, and the low angle of dip allows of their appearance on the eastern bank, where the Great Seam is seen a few feet above the level of the river. It is here 18 in. in thickness, and rests upon fireclay and dark shales with ironstone’nodules, beneath which is a thin seven-inch coal which may be the Stairhead. Above are dark shales and a thick sandstone. The outcrop of this seam is apparently cut off to the north by the fault which crosses the river in the hollow below the Marfield Quarry. On the same side of the river, a little farther to the north, the Flex and Rumbles Coals crop out beneath the steep escarpment formed by the 20-ft. sandstone that underlies the Index Limestone on the top of the bank. Old air-shafts and shallow pits indicate where the Corbie Craig Coal has formerly been worked all through the estate of Newhall, and its outcrop crosses the North Esk near the lower bridge, im- mediately under Newhall House. The Edge Coals underlie the Roslin Sandstone outlier on Auchen- corth Moss, and the lower seams have been proved in several bores along the eastern edge of the basin between Howgate and Leadburn Junction (Sheet 24), Ata point 420 yds. north-west of Venture Fair, the Corbie Craig Seam was found at 19 fms., the coal being 4 ft, 2 in. in thickness, divided into two beds by 15 in. of fireclay. In the other bores the same coal varies from 2 ft. to 3 ft. 3 in. The Beattie and Corbie Craig Seams crop out above the Peebles railway line between Venture Fair and Rose View, and were formerly wrought near Mosshouses by means of a day-level from the Lead Burn. The beds here dip W.N.W. at 30°; but the coal is now only visible at one point, in a sandstone quarry at Venture Fair. L. W. H. * Much of the two preceding paragraphs is taken from Mr. Howell’s original description. “ Geology of Edinburgh” (1861), pp. 90, 91. 216 Carboniferous Limestone Group of Mid-Lothian Basin. TEMPLE FIELD. The examination of the natural sections taken in conjunction with the data obtained from the numerous bores put down by the Arniston Coal Company has made it possible to construct a general- ised section of the beds which come above the thin limestone at the top of the Lower Limestone group. Near the bottom of the section a coal with a parrot band probably represents the Parrot Coal of the Arniston Colliery. It is seen in the South Esk above Temple and also in the bend of the stream below the junction with the Redside Burn, and has been struck in several of the bores of the Arniston Coal Company. The Coal 4 ft. thick near the top of the section at Temple is supposed to be the Kailblades Seam. Higher than any of the strata in the foregoing section are some of the beds with thin coals seen in the little burn running down from Redside, and near the south-westerly continuation of the Vogrie fault. The mapping of the ground south of Carrington and Redside has shown that this fault crosses the South Esk a short way below the junction with the Redside Burn, and is continued in a westerly direction through Red- side and Fatlips, thus truncating the basin of the Coal Measures and Millstone Grit along its southern margin. Bores Nos. 1 to 5 and Bore “No. 15, Arniston Mains, prove the continuation of this fault between Gorebridge and the South Esk, the Upper Limestones being faulted down against the Edge Coal group, and striking at the line of junction. Near Temple, and for several miles farther west, some of the higher beds of the Edge Coal group and the Upper Limestone division have been probably cut out by the same fault, and the thickness of the Edge Coal group preserved between Yorkston and Redside perhaps does not exceed 200 ft. Owing to their gentle northerly dip the strata, however, cover a wide area. Bores Nos. 3 and 4, Arniston Mains, put down by the Arniston Coal Company, in the neighbourhood of Bells Mains, farther to the east near Fushie- bridge, found the Parrot Coal at depths of 361 and 400 ft. The former bore was continued to the limestone, which it reached at 387 ft. At 78 ft.in Bore No. 3 a thick coal was met with, giving the following section :— Ft. In. Coan .. es wa oy a & Ae » BO Fireclay .. a ee #3 a Me ». 1 10 Coat .. 5 ss , : és c. 2 TI In Bore No. 4 the same coal was met at 90 ft, and gave the section shown below :— Ft. In. CoaL .. os ss os i os i - 2 9 PaRROT i 2% 23 23 ai 2 sa Q- Rotew Coat .. ‘3 o -» O 11f This coal probably represents the Great Seam. Other bores show that this coal is restricted to a small basin and probably bounded on one side by the Vogrie fault. The underground workings of the Gore Pit show the continuation of the Roman Camp anticline as far south-west as Arniston Mains, the different level roads following one another in curves as the dip changes from west to south and SS.E. Across the Vogrie Edge Coal Group of Gorebridge, Newtongrange and Cowden. 217 fault the southern continuation of the Roman Camp anticline is also shown by the Lower Limestones coming nearly to the surface near Arniston House, as is proved by Bore No. 16, which commences below the Parrot position and passes down into the limestones. Three miles to the west, on the south side of the supposed con- tinuation of the Vogrie fault near Fatlips, a fine-grained yellow sandstone with no clear dip is first seen, followed higher up the burn by a soft, rather coarse yellow sandstone, which dips W.N.W. These yellow sandstones, and also the sandstones, shales and thin coals seen farther south, in the old quarries near the reservoir for the Roslynlee Asylum, are supposed to belong to the Edge Coal group, but no fossils have been found to prove their Lower Carboniferous age. A seam of coal found in making the puddle trench of the reservoir is reported to be of good quality and thicker than those in the quarries. C. B.C THE GOREBRIDGE, NEWTONGRANGE AND COWDEN FIELDS. In this district, on the east side of the coal basin, coal is now obtained from the following pits: New Gore, Emily (Arniston Colliery Co.), Lady Victoria (Newtongrange, Lothian Coal Co.), Bryans. Much of it is brought from great depths and considerable distances from the winding shafts. The forehead of the “ Carrington Dook” in the Parrot seam in the Lady Victoria Pit is about 2200 ft. below the surface, at a locality about 500 yds. W.N.W. of Aiken- dean Farm. The beds near the forehead are undulating, but are probably on the eastern side of the centre of the basin. In the Lady Victoria shaft the strata between Limestone No. 4 and the thin limestone (at the top of the Lower Limestone group) that underlies the Parrot seam are about 646 ft. thick,* and they include 15 coals of variable quality, which exceed 23 in. in thickness. The total thickness of coal and cannel, without counting partings of dirt, is about 70 ft. Most of the seams cannot, how- ever, be worked with profit at great depths, and in the Victoria Pit the only seams being mined at the time of the revision by the Geological Survey were the Parrot and Bryans Splint. At Arniston the Great Seam and the Kailblades were also worked. The following section shows the coals and intermediate strata as they were proved at the old Cowden Colliery, Dalkeith :— Ft.. In. INDEX LIMESTONE (No. 4) Sandstone and shale (blaes) .. ‘ aa .. 29 4 CoaL (DECEPTION) .. Ss is Be id gmety ol HD) Sandstone. . a ae me Be a .. 80 6 Coat (CRYNz).. a4 ed = wi a x 2 6 Sandstone. . ie af 5 a ie .. 24 6 Shale - 53 3 2 i ie . 4 8 Sandstone a3 ia es 2% £4 .. 24 4 Coat (Mavis) .. ie si oe st ics a 2 8 Sandstone ah = Me wa a .. 62 2 -Coau (GREAT SEAM) .. aa is af es we, 84 FO) Sandstone a ae is s2 hs in OO Carry forward .. 197 10 * In these measurements a deduction has been made for dip. 218 Carboniferous Limestone Series of Mid-Lothian Basin. Brought forward Coat (Dramonp) s is is i Sandstone and shale Coarse blackband ironstone Coat . Shale with bands Coat (SILLER WILLIE) Sandstone CoaL .. Sandstone bands. . CoaL .. Shale Coan .. Sandstone bands. . Ironstone ‘in balls os ee ay CoaL .. a és = ss 2% 8 Shale on 8 on a oo o Edge Coal Group of Newtongrange. 219 Of the seams mentioned in the above section the chief can be recognised in the Lady Victoria and Emily shafts, as shown by the following considerably shortened sections :— Portion of Section in the Lady Victoria Shaft. Ft. In. InpEx or No. 4 LIMESTONE. Strata CoaL.. Strata Shale, parroty CANNEL : TRonsTONE CoaL.. CANNEL : Shale, parroty Strata CoaL.. Strata Coa. 7 Sandstone . Coa. Bastard fireclay Coa. . Strata Sandstone. Great Sram Coan. Strata Diamond Coan Strata CoaL . Daugh and blaes . Coax with daugh parting « Ironstone bands Coat. ‘ Blaes CoaL. Blaes LIMESTONE bands .. Strata with thin Coan CoaL . Blaes Coal .. Blaes CoaL.. ooo00ne NOrOorF Carry forward Portion of Section InpEx or No. 4 LIMESTONE. Strata CoaL .. os Fireclay .. CoaL ., : Fireclay .. CoaL .. a Strata Carry forward + po~Teconore gi. + - bo moore? Dp pi it a “I 10 #1 1 il 13° =«7 oo toe bo bo bo toe bo _ poe bo CNHNNFNONNWHE WHE ROOK KRAOYH DW _ — an SOPOEEO RST Cy OE Se Ft SO OG SOR JE S00 SO OVI RO 2 bo . 204 9b Ft. In. 20 11 7 0 T. 5 1 8 87 9 Brought forward Strata es Coat, BLACKBIRD Strata ee Coat with blaes parting Strata with thin Coal Coat, CoRONATION . Strata ‘ Bastard limestone Blaes CoaL.. Strata SmitHy Coan Strata with thin Coal SPLint Coa, waste Strata with thin Coal Coax with daugh penne = Strata , CoaL . Strata Bd KalnBhaDEs CoaL partings of fakes Strata LittLe SPLINT Coan Strata CoaL.. Blaes CaNNEL CoaL Strata partings Strata os Ironstone (the “ bane ”» JEWEL CoaL jason Parrot Coa ARROT CoaL Sieber Bottoms Coan Witp Coat .. Strata LIMESTONE. in Emily Shaft. Ee forward CoaL .. Fireclay .. White sandstone Great Szam Coat .. Strata Diamond Coan | Strata Carry forward . 204 with Little Coa with blaes Ft. In. ve} we toe w or ol ra HWOrFORMNPRONNMNOOADWaArd a ew e Onn SA Oner toe Oo ~ ye DOOM Wwe ~WS or 646 2 eR 220 Carboniferous Limestone Series of Mid-Lothian Basin. Ft. In. Ft. In. Brought forward .. 180 4 Brought forward .. 421 7 CoaL .. ant ee - 2 4 |Coan.. ow ae wo 2 9 Strata .. les we 23 38 Strata 6 6 Coan .. a on -- 2 8 |Coar.. 1 38 Strata .. ae .. 29 8 Strata is 17. 8 CoaL .. 3 3 | KarnpnapEs CoaL .. 3 10 ~ Strata 13° 0 Fireclay and blaes 2 6 CoaL .. 1 6 | Lirrie Spiint Coan a Strata wool Strata .. ne ee: Mer! <2 CoaL . et 0 11 | Goar RoveH 0 9 Fireclay .. 0 ll ‘oo 1 3 Coat .. 1 10 Blaes 1 7 Strata 9 3 | IRoNSTONE Pe sie, OPT CoaL .. 1 1 Blaes .. ai .. 14 11 Blaes 10 6 |CoaL.. 9 1 CoaL .. 2 1 Blaes 1 6 Strata 32 6 |CoaL.. ‘ 1 3 Coat .. 1 4 | IRoNSTONE BANDS 2 9 Strata 14 oil Blaes 9 #7 Coa .. 1 7 | Ironstone Oo 2 Strata 31 67 Blaes 0 6 SPLINT CoAL.. 3 9 | Parrot SEAM 2 3 Strata with thin Coal . 368 ——— -_—- 570 10 Carry forward .. 421 7 —— If the Lady Victoria section be compared with that of Cowden it will be observed that in the latter the interval between the coals called the Blackbird and the Coronation is only 64 ft, while in the former the interval between the same two coals is more than 58 ft. The thickness of the Edge Coal Group down to the Parrot Seam in the Emily shaft is about 50 ft. less than at Cowden, and a similar diminution of thickness in a southerly direction continues south of the Emily shaft (see p. 194). The Parrot seam—the lowest of the Edge Coals—is not, on the average, more than 3 ft. thick, but it is often profitable to follow it to great depths as it contains, near the middle, a thin seam of Parrot which is a very good gas producer (1903), and the upper portion, the Jewel Coal, makes also an excellent house coal. At Arniston and Newbattle Collieries the Parrot varies between 6 and 9 in. in thickness, but farther north it becomes thinner, and in the old Cowden Pit is said to be only aninch. Above the Jewel portion of the coal we find 2 or 3 in. of dark, finely laminated shale containing abundant remains of Lingula, overlain by a band of ironstone, called the “bane,” which is about 3 in. thick and is said to be very persistent. The ironstone makes a good roof to the coal workings and yields in places abundant remains of Carbonia (7). The Lingula shale was found in the Lady Victoria Pit, the Emily Pit, and an old level at Common (Gorebridge), and judging from the waste heaps at the tops of many of the old abandoned pits it must be of general occurrence in the Newtongrange and Gorebridge district. The shale (blaes) 6 or 8 in. above the “bane” contains, in parts of the Carrington Dook of the Newbattle Colliery, lamellibranchs, determined by Dr. W. Hind to be Naiadites carinata and. Naiadites modiolaris. This shale is believed to be the lowest Edge Coal Group of Newtongrange. 221 horizon in which these fossils have yet been found* In England, they are said to characterise the Lower and Middle Coal Measures. In the Lady Victoria Pit a band of hard calcareous sandstone,t about 5 ft. thick, is found 34 ft. below the Little Splint Coal, and contains along certain bedding planes an admixture of small black grains of tourmaline. A thin seam of Zingula shale occurs in some places just above the Kailblades or Rough Coal, between 100 and 140 ft. above the Parrot Coal. It was stated to occur at Bryans by Mr. D. Milne Home,t so long ago as 1839, and is well exposed at Common (Gorebridge), where it is 2 or 3 in. thick and overlain by 15 in. of shale with ironstone nodules, but in the Lady Victoria Pit it has not been detected. The Kailblades is used as a steam coal. In both the Emily and Lady Victoria Pits it is much mixed with partings of clay and thin- bedded sandstone, frequently full of vertical rootlets. The two coals, about 8 ft. apart, which are exposed in the old quarry at the north end of the wood between Lawfield and Langlaw, probably represent two portions of the Kailblades Coal with a thicker separation than usual. A sandstone that occurs a little above the Kailblades Coal is about 40 ft. thick in the Masterton Quarry and contains numerous quartz grains-as large as a pea, being much coarser than most of the sandstones which occur in this district in the Edge Coal group. In the Crossgatehall railway cutting there is, however, an equally coarse sandstone slightly below the Great Seam, and at Gilmerton the strata between the Great Seam and the Index Limestone chiefly consist of rather coarse sandstone or grit (p. 199). The Bryans Splint Coal is sometimes 6 ft. thick, and is an excellent house coal. Parts of it are of hard splint coal which can be got in large blocks, and above it we often find 12 or 13 ft. of shale with small nodules of ironstone and thin even courses of sandstone. The Coronation Coal in the Lady Victoria shaft is pyritous and somewhat liable to spontaneous combustion. About 24 ft. below this seam, a thin limestone, rather more than 2 ft. thick, was cut in sinking the Lady Victoria shaft. A search was made for this band in the “ Newbattle incline,’ and a calcareous sandstone, 2 or 3 ft. thick, with abundant remains of Productus semireticulatus, was found between 20 and 30 ft. below the coal. This calcareous horizon is rather more than 300 ft. below the Index or No. 4 Lime- stone, and not far from the middle of the Edge Coal group. It is not recorded in the shaft section of the Emily Pit, Arniston. In the roadway into Shaw’s Quarry, a quarter of a mile slightly east of north of West Houses, three coals are exposed, varying between 14 and 24 in, in thickness and dipping about 24° to W.N.W., as well as a lower coal, 3 ft. thick, which has been worked by an “ingoing eye.” All these coals must lie a little below the Diamond Seam and probably above the Coronation Coal in the Lady Victoria shaft, but they cannot be correlated confidently * They occur on a higher horizon in the same group (p. 230). + Locally called Waittie’s toe. tf Op. cit. p. 38. 222 Carboniferous Limestone Series of Mid-Lothian Basin. with coals shown either in that or in the Cowden section, the beds on this horizon being evidently very variable. At the entrance to the quarry the casts of two big tree stems—one of which is Sigillaria—are seen in a flaggy sandstone above the three-feet Coal. They stand almost at right angles to the bedding planes and are perhaps 4 ft. high. One of the stems must have been at least 2 ft. in diameter. Limestone bands, about 30 in. thick, are stated to have been pierced about 40 ft. below the Diamond Coal in the Lady Victoria shaft. The beds on this horizon are not now visible in any part of the colliery, nor in any surface exposure in the neighbourhood. At Crossgatehall—four miles away—no corresponding calcareous band has been detected. The Diamond Coal is considered an excellent house coal though thin. The Great Seam is 6 or 7 ft. thick at Arniston and Newbattle Collieries and near Smeaton Shaw. At the Arniston Colliery it is not of very good quality and is classed as a steam coal. In all these places it contains a band of parrot a little above the base, but this band is not of such good quality as that from the Parrot Coal, and at Arniston Colliery, where it is 3 in. thick, it is sent up separately. The Great Seam is exposed obscurely near the western end of the Crossgatehall railway cutting, where it contains, as usual, a band of parrot near the base: above the coal comes a rather massive sandstone about 30 ft. thick, which is well represented also at -Gorebridge, Newtongrange and Cowden. The Mavis Coal is exposed at the mouth of an old “boot gate” in a little wood at the junction of the roads a quarter of a mile $.S.W. of West Cowden. It is about 3 ft. thick and overlies a bed of shale, 20 in. thick, which rests on a sandstone, at least 35 ft. thick, coming above the Great Seam. Above the coal there is a bed of shale a foot thick, and then a band of ironstone from 4 to 5 in. thick. Good surface exposures of the beds under review are rare. The best are those at Common (Gorebridge), in old quarries near East Houses and Lawfield, and in the railway cutting at Crossgatehall on the north-west side of the fault, with a large downthrow to the north-west, which crosses the cutting 90 yds. east of the bridge. The last-mentioned exposure furnishes the most extensive section, the details of which are given below in descending order :— Section in the Eastern Part of the Crossgatehall Railway Cutting. Ft. In. Sandstone 2 O Gap in a 1 0 Flaggy sandstone 1 6 CoaL .. ee a Re an ae 1 Oo Thin-bedded sandstone with rootlets .. 1 6 Massive sandstone 3 0 CoaL .. 5 ; 1 0 Sandy shale 1 O Sandstone ate 2 0 Gap 15 0 Carry forward .. 29 0 Edge Coal Growp of Crossgatehall. 223 Ft. In. Brought forward 29 0 Sandstone i 5 ee 30 0 Small Gap ? BRIGHT Coan 2 O Parrot CoaL ee L.. 2 Brieut Coat a 0 5 Sandy clay at 0 2 Coan 0 6 Sandy clay ss ai a ia as Pe xg O 2 Ga oe Pe es ie Bi sie 26 .. 4or 5 O Shales and thin sandstones, often with rootlets 8 O CoaL .. zis 1 #0 Shale 1 #0O Alternations of sandstone and shale, “the former rock in excess near the top s : aa Shale . ee a “ye Sandy shale and shaly sandstone a be sp Sandstone : ae : CoaL .. Fireclay Alternations of shale and sandstone Shale with ironstone 2 Bricut Coat (bottom not seen) Shale with ironstone nodules .. Sandstone. . ‘ Fireclay OAL .. m2 Clay cate Brieut Coan ee f Parrot CoaL | a wo _ WOTDOKFOCRFOROKFOADUNOOCAN® owocoo Clay Carberry ? e Briaut Coan Sandy clay Massive sandstone Blue and grey clay and ‘shale, with ironstone layers and a 3-in. band of Parrot Coal close to top a8 Alternations of sandstone and shale Coan .. s Mostly sandstone Coan... Massive sandstone s Coat, splinty near top and with a Tin. parting of shale near middle a Sandstone with rootlets. . , oy a ae as Shale Coat with some Parrot near “middle Massive sandstone Shale and thin-bedded sandstone Massive sandstone ofa Thin-bedded sandstone with shale partings sie Shale with ironstone asi Coat with lumps of aaa Fireclay wo _ Hb Ke OMODDODOCOOEABVOIV9CO DCS CORFE ODUDHrFOOOrCO ; bo SHE NOTOMDHFNOWWOHODH ON o | | a eo 310 Oo The total thickness amounts to about 310 ft. The coal with lumps of pyrites near the base of the section is seen on the south side of the railway cutting. On the north side a coal mixed with ‘ironstone and parrot appears to be nearly on the same horizon, but the section here is not clear. The direction of dip varies between E.N.E. and N.N.E. and the angle between 25° and 30°. The general dip in the Gorebridge-Cowden district is slightly 224 Carboniferous Limestone Series of Mid-Lothian Basin. north of west at angles varying between 10° and 25°. Near Gore- bridge, the outcrops are affected by the anticlinal fold of the Roman Camp ridge, at the south end of which the arch pitches to the south, and the dip changes gradually from west through south-west and south to south-east. Hence the outcrops of the lower coals— including the Bryans Splint, Kailblades and Parrot—form ‘curves with the convexity pointing nearly south, but the crops of the Great Seam and overlying strata are abruptly truncated by the great Vogrie fault. On the north side of Kast Houses the outcrops of the lower beds —from the Bryans Splint downwards—are also affected by a roll over towards the east, and though they are not distinctly seen they must in places be separated by wide intervals from those of the higher seams. Thus while the outcrop of the Edge Coal group on the west side of the Roman Camp ridge is slightly less than a mile broad near Newtongrange, it is a mile and a half near Cowden. The axis of the fold referred to strikes N.N.E., in much the same direction as that of the Roman Camp anticline. On the south side of the old quarry at the north end of the wood between Lawfield and Langlaw the beds are plicated along two small folds with axes striking nearly east and west. The Parrot Coal appears to have been formerly worked in at least two places nearly half a mile slightly north of east of Lawfield, and it is believed by miners to extend over the hill eastwards to Edgehead. It is said to have been proved in a boring a little west of the fault, with downthrow to east, which bounds the Edgehead workings. The Vogrie N.N.E. fault, which has been adopted as the south-east margin of the area now being described, has, near Gore- bridge, a downthrow to the north-west of about 40 fms. In the Vogrie Pit the depth of the Great Seam is 10 fms. and that of the Bryans Splint is 50 fms., while in a bore about 500 yds. south-east of the pit the Splint is only 6 fms. deep"and is dipping gently north- west. The surface position of the fault can be located in the Gore Water, where there is an exposure of Limestone No. 4 little distance on the north side of it. From a comparison of the underground with the surface positions the hade in this locality is made out to be 52°, A little north of the Emily shaft two large nearly east and west faults throw the beds down into a trough. A quarter of a mile east of Hunterfield the displacement of the southern fault has been proved in the Bryans Splint Seam to be 186 ft. down to the north, but it rapidly diminishes in a westerly direction, and 730 yds. farther west, is only 18 ft. The northern fault is said to have a downthrow of 185 ft. near Greenhall, but about half a mile west of Greenhall the displacement in the Great Seam is only 90 ft. Eastward from Greenhall this fault truncates the limestone at the end of the Roman ‘Camp ridge, but the downthrow cannot be large, the limestone on the south side of the fault having been found only a short distance below the surface. At Bryans the strata are thrown down to the north 12 or 14 fms. by an east and west fault, which was lately exposed at the surface in a position 150 yds. north-east of the pit head; the crushed rock accompanying the fault is several yards in breadth. ‘Edge Coal Group of Newtongrange. 225 An important line of disturbance striking north-east or N.N.E. and represented either by one or two faults, both with a large downthrow to the north-west, has been met in the Cockpen Dook, in the Newbattle Incline in the Lady Victoria Colliery, and in workings near East Houses. In the Cockpen Dook the fault plane has not been driven through, and the amount of downthrow is not known. The position of the south side of the fault in the Parrot Seam, at a depth of more than 2000 ft. beneath the surface, is about 30 yds. south of Cockpen Bridge. In the Newbattle Incline there are two large dislocations, one with a displacement of 240 ft. and another of 168 ft. Near East Houses the main fault has a throw of 120 ft. and is accompanied, on the south-east side, by a nearly parallel minor fracture of 30 ft. In a north-easterly direction from East Houses the disturbance has not been proved in mining, but it seems probable that it runs to the east of the outcrop of the Great Seam. Perhaps it is represented by the N.N.E. fault that crosses the Crossgatehall railway cutting, the downthrow of which is in a north-westerly direction, and must be large, perhaps as much as 500 ft.,the greater part of the Edge Coal group being cut out by it. A north-west fault on the south side of Wester Cowden has a downthrow to the north of 90 ft, and to the north of this locality two faults strike nearly north-west and have a displacement to south- west amounting to 30 and 42 ft. respectively. The east and west fault passing about 100 yds. south of Cowden Cleugh * was formerly regarded as the continuation of the Sheriffhall fault. Perhaps it may be a branch of this great line of disturbance, but Mr, R. T. Moore has lately proved by boring operations that its downthrow is not likely to exceed 40 or 50 ft. at the head of the Cleugh. Cc. T. C COAL-FIELD EAST OF GOREBRIDGE AND OF THE ROMAN CAMP RIDGE, North-east of the Gore Water, coals have been worked from the Vogrie Pits, two of which are situated on the western or downthrow side of the Vogrie fault and have worked the Parrot, Kailblades and Splint Seams. The Kailblades and the Splint have also been worked on the eastern side of the fault from three pits between Harvieston and Mountskip Farm. The Parrot Coal has been proved in bores but has not been worked on the eastern side, being apparently too thin to repay mining. This is indicated by the following section derived from an old bore put down near Harvieston, on the south- east side of the Vogrie fault :— Section of the Strata at Harvieston. Ft. In. Surface .. ies 6 6 Fireclay . . i a 0 6 Sandstone and shale .. 5 5 Sort Coan .. sts Ss 0 7 Sandstone and shale .. 8 5 Carry forward .. 21 6 * Not named inthe new edition of the one-inch map, but situated in the wood east of Cowdenfoot, TS 226 Carboniferous Limestone Series of Mid-Lothian Basin. Ft. In. Brought forward .. 21 5 Coat (impure) a a ‘a ane ae ea 0! Sandstone és x ae x ne -- 10 5 SpLint Coat (waste) 3 0 Sandstone and shale .. 26 «5 Coa. . 1 3 Sandstone and shale 24 9 Coan ‘ 1 4 K Fireclay Oo 4 AILBLADES } (ig 43, ; 1 7 SEAM. Fireclay 1 5 CoaL “3 1 8 Sandstone and shale aa ae ang are .. 91 6 Parrot Coan oa 6 ay si . O 4 Sandstone and shale ae se a ste «a B81. °F LIMESTONE, 217 4 It will be seen from the above that the valuable Parrot Seam of the Newbattle and Arniston Collieries is only 4 in. thick in this bore. The Parrot Coal was formerly worked from a pit north of Hillhead on the downthrow side of the fault that traverses the Roman Camp ridge from Edgehead, where it has been proved in the coal workings, towards Mansfield. The coal that has been worked from the crop in the Camp Wood is considered by miners to be the Kailblades. Within the limits of Sheet 32, Edgehead Colliery is the only place where coals are now worked on the eastern side of the Roman Camp ridge. The Splint Coal, which represents part of the Kailblades of Arniston, is the only seam being worked, but the Parrot Coal was formerly mined over a wide area from several pits near Edgehead. To the south-east of Edgehead the Cherry Coal, on a higher horizon than the Splint, has also been wrought. The Parrot Coal workings in this district have been carried as far north-west as the fault that runs E.N.E., between Mansfield and Edgehead, with a downthrow to the south. A second large fault, with a downthrow to the west, which may be a continuation of the Vogrie dislocation, has been met with in the workings about half a mile south-east of Edgehead, and limits the Parrot workings on the east. The following section of the coals and intervening strata at Edgehead has been communicated by Mr. Johnston, Manager of the Edgehead Colliery :-— Ft. In. Strata.. oe be aug oe .. 96 O Barns Coan a4 ee aa ay ie 2 @ Strata. . ee su Gap. candfene ie os Sandstone with some fakes .. Coarse pebbly rib with clay a and d pyrites Sandstone ce CastLEcary or No. 6 LIMESTONE. or WOOWHOH OGOWVWRORWO aD In the upper portion of the series thin conglomerates often occur, showing a rather coarse matrix of, yellow sandstone and many fragments of pale. grey clay, dark grey shale, coal and parrot shale, together with occasional pieces of hard siliceous sandstone or ganister. Most of these ingredients vary in length between } in. and 3 in, and are rather angular in outline. Large fragments of vein quartz, such as frequently characterise the coarser-grained sandstone bands, are not conspicuous. These conglomerates are sometimes 2 or 3 ft. thick, and display indications of erosion or of local unconformity at their base, the edges of some of the lower beds having been denuded * See note at the end of this chapter. 248 Roslin Sandstone Series of Mrd-Lothian Basin. before the overlying conglomerate was deposited. But similar instances of local unconformity are common throughout the series even where no conglomerate is seen. The individual beds of con- glomerate cannot usually be traced more than a few yards. Good examples can be seen on the east bank of the Esk about 660 yds. 5.S.W. of Melville Castle, and again on the south side of the river, 150 yds. north of Polton House. In the former locality two bands of conglomerate are exposed, one 3 ft. above the other, and in the latter locality there are also two, one 10 ft. above the other, with unusually large pieces of coal—one more than a foot long and 6 in. thick. The bands often contain large pieces of Calamites which seem authigenic. They do not appear to have been rolled or derived from a pre-existing bed. It might be supposed that the conglomerates occur near and in connection with the paleontological break, but from the informa- tion provided by a bore which has been put down about 70 yds. W.S.W. of the south lodge of Melville Castle, it would appear that all the conglomerates observed must be nearer the top than the bottom of the series. About 200 yds. west of Hawthornden Castle conglomerates are to be found with. pieces of pale grey clay, as much as 3 in. long (but without any coal or dark grey shale), which are probably not more than 150 ft. below the top of the series. Between Roslin Castle and the eastern entrance to the Powder Mills, two faults are seen, and there is probably a third. One of these, with a north-west strike, crosses the big loop south of the Castle, and throws down the top of the series to the south-west, perhaps 40 ft. Another, with a similar strike, but hading in the opposite direction, makes a distinct break on the south bank of the river a quarter of a mile slightly south of west of the Castle. It is not accompanied with much crushing, but the amount of throw is not known. A third fault is inferred, because the top sandstone of the series is only a few feet above the Esk in the most southern portion of the big loop south of the Castle, while, in a locality less than a quarter of a mile farther north-west, we find beds of sandstone and shale which are probably less than 200 ft. above the Castlecary (No. 6) Limestone. The rock in the area between these two localities is not well seen, but it shows no indication of a steep dip such as would be required to bring in all the middle portion of the Roslin Sandstone series. In the workings in the Edge Coal group a little north-west of Roslin village, a fault has been proved striking N.N.W., and with a downthrow to the east of 168 ft., which is supposed to be a continuation of a dislocation crossing the Esk near the Carpet Works. All the strata between the Carpet Works and the exposure of the Castlecary (No. 6) Limestone, rather more than a third of a mile slightly west of south of Oatslie, probably belong to the lower portion of the Roslin Sandstone series. A coarse massive sandstone, at least 60 ft. thick, is well seen on the east bank of the Esk, a third of a mile south- east of Oatslie, where it appears to be resting with a very uneven base in denuded hollows of the underlying fireclay. A little below the sandstone, but on the other side of the river, a coal 8 in. thick is seen. Some hard calcareous flaggy sandstones on the same Pemcutk Area. 249 horizon as those which, in the South Esk, lie between 100 and 170 ft. above Limestone No. 6, crop out below the coal, and a little below these calcareous strata another coal about 6 in. thick is exposed. The remains of the following plants have been found in beds not far below the thick sandstone :— Lepidodendron rhodeanum Stern C. $3 veltheimianum Stern C. Calamites, several sp. The beds in this locality are nearly flat, and the outcrops of Limestone No. 6 and the lowest coal are almost on the same level, from which it may be inferred that these two outcrops are separated by a fault with a downthrow to the north-east. Perhaps this dislocation is a continuation or branch of the Vogrie fault which skirts the southern margin of the coal basin. C.T.C., J.8.G. W. PENICUIK AREA. The northern portion of the area of Roslin Sandstone, which lies to the south of Penicuik, occupies one of the minor troughs due to the system of shallow folds into which the strata in this part of the district have been thrown. The northern end of this syncline is cut off by an E.S.E. and N.W. fault, which crosses the river Esk at the Valleyfield Paper Mills and has been proved in several bores in the ground farther to the east and west. The fault has a downthrow to south and brings the sand- stones against the rocks of the Upper Limestone group in the river. The western boundary of the sandstone is also shifted a few hundred yards to the south by the fault which crosses the Esk and the Hare Burn. A good section of the sandstones is exposed in the steep southern bank of the Esk in South Bank Wood, where thick-bedded white, grey and reddish gritty sandstones and pebbly bands, with intercalations of thin fakes and purplish sandy shales, dip east at 15° to 20°. A short distance lower down in the series there is a curious bed of fragmental rock made up of angular stones derived from volcanic material, in a sandy matrix. A similar rock is found in the Hare Burn, associated with pebbly grits and friable yellow sandstones. The journal of a bore put down through the Roslin Sandstone at a point in the Hare Burn, exactly one mile above Hare Burn Bridge, gives 79 fms. of sandstones and fakes above the highest limestone (No. 6), with a 1-ft. seam of foul coal at 53 fms. ~ L. W. A. CARRINGTON, NEWTONGRANGE AND SMEATON AREA. Excellent sections occur in the lower part of the series in the South Esk, for a quarter of a mile below, and about a mile above, the junction with Gore Water, but some of the beds are very inconstant in thickness. Rather more than a third of a mile south of the junction of the Esk and the Gore Water, a W.N.W. fault, which has a consider- able downthrow to the south, crosses the Esk at Shank, but the beds 250 Roslin Sandstone Series of Mid-Lothain Basin. on either side of the fault cannot be correlated with confidence. sections on both sides are given below, in descending order :— Flaggy sandstone: .. es Mottled red and buff i impure clay with rootlets 2h Hard irony sandstone. . is Mottled red and yellow sandy clay. Soft flaggy red and yellow sandstone oe soft yellow sandstone a os < Firecdey, pale grey _ Purple and red shale with fish remains at. the base Fireclay. Red ane Yellow flaggy sandstone with rootlets Sandy nodular clay, pale grey and red, with rootlets Flaggy yellow sandstone with rootlets and many Upper Carboniferous plant remains a Purple or greenish shale with fish remains in the lower part Soft yellow false-bedded massive sandstone with remains of tree stems es oe “a Purple-red shale $s Notulas red and yellow LIMESTONE with corals and other fossils . ess +. a ie Mottled red and yellow fireclay Soft yellow sandstone Soft mottled sandstone, red, yellow, lilac, ete, Flaggy sandstones and sandy clays .. Dark grey shales and thin in flagey hard ‘calcareous sandstones Coal streak ae ee Pale grey fireclay ... ane ae ee me Massive soft yellow sandstone ae ae oe Dark grey shale 2 Pale grey fireclay : ak Gap ag. eps Massive yellow sandstone .. es se Dark grey shale sd a Sao iss a Gap risk ae «e ae we 7 Pale grey, ‘freslay 5 a a Soft massive sandstone, yellow, purple or white .. Dark grey shale with some thin ironstone courses CastLEcary or No. 6 LIMESTONE. Section in the South Esk on the North Side of the Shank Fault. Ft. In. 1 90 3 0 0 6 Oo 9. 2 3 18 O. 9 O 2 O 2 O 0 6 I 9 3 #0 1 8 5 4 72 6 1 0O 9 0. 2 0 13 O 2 6 49 6 13 (=O 12 #O Oo 04 5 60 7 6 0 6 2 O 10 O- 8 0 7 O 20 O 2 v0 45 O 35 60 367. 3}. —— The The remains of Upper Carboniferous plants and fishes which were collected from a flaggy sandstone and a purple shale near the top, are as follows :— Pleuroplax attheyi (Barkas). rankinei (H. & A.). Rhadinichthys monensis (Egerton). Lepidodendron obovatum Sternd. - aculeatum Sternb. Cf. Sigillaria sillimanni Brongt. - Clathrate Sigillaria or ee Lepidostrobus. i Carrington, Newtongrange and Smeaton Area. 251 Section in the South Esk on the South Side of the Shank Fault. . Ft. In Sandstone. Shale .. i a ae is 0 ae Flaggy sandstone Dark grey shale, basal } art with Leptdodendron ghincanewm 18 Purple and dark grey shale .. Grey and buff fireclay. . 2 ais Massive yellow and red sandstone .. im ahs ie 19 Gap. a as ie ae Fe ws «62 Pale grey ‘fireclay ix ; ee id ae 22" Brown and yellow massive sandstone... ose .. 42 Pale grey and red mottled fireclay . .. 16 Red calcareous impure ironstone with spheerosiderite iy 2 Mottled yellow and red fireclay 8 Massive soft white and deep red false-bedded sandstone.. 62 Flaggy purple and grey sandstone .. a ee ae | Yellow and red sandstone .. 3 Gap, including supposed position of a marine ironstone visible in an adjoining section farther south* . Yellow and white sandstone . ‘ oi Pale grey fireclay .. Ga Yellow sandstone Pale grey fireclay Yellow sandstone Dark purple shale Calcareous hard flaggy sandstone Shale .. Black carbonaceous shale or smut a Purple and pale grey shale and caus fireclay Yellow sandstone : Gap Ga eaveods sandstone with Orthotetid shell Shale .. Calcareous sandstone with Orthotetid shell. Shale te ‘ CASTLECARY or No. 6 LIMESTONE. The shale which contains Lepidodendron glincanum contains also— Calamites ramifer Kidston. - Lepidostrobus variabilis L. é& H. Lepidodendron gaudryi Renault. Lepidophloios. _ Stigmaria ficoides Brongt. Productus sp. Cf. Anthracomya valenciensis R. Eth., Jun. Rhizodopsis sp. The estimated interval—232 ft.—between Limestone No. 6 and the higher marine limestone in the first section is greater than that between Limestone No. 6 and the supposed position of the marine shale and ironstone in the second section, which is estimated at 150 ft. The higher limestone has only been seen in one place, and the ironstone does not occur in all the localities where it might naturally be expected, but these two beds may probably be on the same horizon. On the N.N.E. side of the fault, the interval between the marine limestone referred to and the plant bed with Upper Carboniferous forms is about 89 ft., while on the S.S.W. side the interval between the ironstone and the plant bed which contains Peete glincanum is about 177 ft. a : * See note at the end of this chapter, bo — > e aonwso DHORDDVDOROBDRDGVVCOOHDSCCS DPOSCRPOVORARMRBODOVSCSOSCSO OCH NWWREOOROCAAMH sf ow 252 Roslin Sandstone Series of Mid-Lothian Basin. If we consider merely the relations of the plant beds to Limestone No. 6 without correlating the marine limestone and ironstone, we find that the bed that contains the undoubted Upper Carboniferous assemblage is about 322 ft. above this limestone, while the band with Lepidodendron glincanum is 326 ft. above that horizon. At the top of the Lady Victoria shaft, Newtongrange, a thickness of about 110 ft. of the lower part of the series is passed through, about half of which consists of shale. A coal, 7 in. thick, is pierced about 95 ft. above Limestone No. 6, and probably corresponds to one of the coal smuts in the South Esk. In the railway cutting a third of a mile south-east of Smeaton Station, various beds which seem to belong to this series are exposed on the south side of a sandstone quarry, but it is probable that a fault passes in a nearly east and west direction between the quarry and the cutting. Among the beds in the cutting we find an impure limestone, 3 ft. thick, containing crinoids and Alveolites depressa, which is considered to be on the same horizon as the marine limestone in the South Esk, and the equivalent of the lowest of the calcareous horizons—which also contains Alveolites depressa—in the Roslin Sandstone series on the east side of Port Seton harbour (one-inch map 33). Just below this limestone there is a grey shale, and about 70 ft. farther down comes a similar bed containing calcareous nodules and marine fossils, which is underlain by a coal about a foot thick. Cc. T.C. MUSSELBURGH AREA. On the shore at Musselburgh the low angle of dip and the false- bedded character of the sandstones do not permit accurate or de- tailed measurements, but the following approximate thicknesses may be given. The Six-foot Coal is underlain by false-bedded sand- stones and shales about 100 ft. thick, and these in turn by about 25 ft. of shales with an ironstone band containing marine fossils, while at the base an impure coal yields plants of Upper Carboniferous age. Descending in the. series, we find next in order a coarse grit, about 100 ft. thick, forming Westpans Rocks, which contains near the summit a specimen of Lepidodendron veltheimianum, visible at low water. The grit is underlain by shales and thin grits perhaps about 60 ft. thick. At the top the marly shales are mottled and contain marine fossils, and near the base a shale yields plants (Plant Bed No. 1 in 6-in. Sheet Edin. 4 N.W.) of Lower Carboniferous species. A little distance above this plant zone a limestone band contains numerous marine fossils. -At the east side of Westpans Rocks there are some interesting cases of false-bedding in thin lenticular sandy shales, in which the more sandy lamine are arranged in a succession of minute sharp curves with axial planes lying at gentle angles to the horizon and nearly parallel to one another. In some beds the minor lamine are also crossed by a number of parallel planes, along which there seems evidence of slight displacement, and which are almost parallel to the axial.planes of the curves alluded to. It might..be suggested that the minor lamine are here crossed by.a set of cleavage planes or strain slips, and that they are probably parallel to some obscure Musselburgh Area. 253 thrust planes. But no planes of movement have been detected in the neighbourhood, and there is no perceptible crushing or shearing in the rocks. It is obvious that the curves and planes of displace- ment were formed before the overlying rocks were deposited, and before the beds affected were consolidated. Perhaps a series of sliding motions or “creeps” down a gentle slope may have caused certain beds to be folded and broken while they were still in a soft condition. © 7. 6, W. G. NOTE ON THE LAMELLIBRANCH FAUNA FROM THE MILLSTONE GRIT. The beds marked with an asterisk on pp. 247 and 251 yielded to Mr. Tait the remarkable assemblage of lamellibranchs referred to on pp. 52 and 53, Chapter V1. CHAPTER XIII. THE COAL MEASURES OF THE MID-LOTHTAN BASIN. In the south part of the Mid-Lothian basin the base of the Coal Measures is drawn below the fireclay seat of the Jenny Meggat Coal, which is the first seam above the barren Roslin Sandstones. In the:north part, it is also drawn below the seat of the first coal overlying the Millstone Grit, which, in the neigh- bourhood of Joppa, is the Seven-foot Coal, and near Cowpits, the Six-foot Seam. Near Hawthornden the Jenny Meggat Coal is about 130 ft. below the Parrot Rough seam, and, one or two feet above the latter horizon, a band of shale and ironstone charged with the lamelli- branch, Carbonicola robusta, has been detected in some localities, but not as yet at Whitehill. This band was lately found by Mr. Gibson, but it was known to the late Mr. James Bennie of the Geological Survey many years ago. A similar fossiliferous band occurs above the Fifteen-foot Coal of Joppa, and has been found by Mr. Tait above the same coal in the New Craighall Pit* and also above the lowest coal in the little basin of Coal Measures at Port Seton. It is also stated by Mr. Milnet that a band of fossil shells occurs above the Three-foot Coal of Cowpits. In all these places the bands are believed to be on the same geological horizon, though the intervals that separate this horizon from the line mapped as the top of the Roslin Sandstone series vary greatly in thickness. This variation is shown by the following tabular statement :—- Ft. Supposed approximate distance at Brunstane, Joppa be «. 215 5 ‘ » ina “crosscut” at New Craighall 171 ‘5 7 % on Joppa shore .. si .. 150 9 4 » at Whitehill es se .. 136 ” 5 » at Port Seton ag ou .. 38 » 3 » at Cowpits .. 5x oi -. 80 At Brunstane and on Joppa shore three thick coals occur in the interval, at Cowpits two, at Port Seton only one, about a foot thick, but it is noteworthy that the last of these contains a seam of Parrot, * Op. cit. p. 18. ; + Dr. Wheelton Hind has examined the specimens from this pit and finds both Carbonicola robusta and C. acuta. {Since the above paragraph was written, Mr. R. Martin, ery eae of Niddrie Colliery, has inferred from recent mining exploration that the Three-foot Coal of Cowpits corresponds to the Nine-foot of New Craighall, not the Fifteen-foot. At New Craighall the Nine-foot Seam is 18 or 19 ft. above the Fifteen-foot. Should Mr. Martin’s correlation be definitely established, it would seem possible that Mr. Milne’s information was incorrect, and that the band of fossil shells referred to by him occurred above the Six-foot Coal of Cowpits, not the Three-foot. At Cowpits the Six-foot Seam is onlyg9,4ft. below the ares et General Descruption. © 255 like the Parrot Rough Coal, of Whitehill: and Polton. The great thickness at Brunstane seems largely due to the presence of a thick red ‘sandstone, 100 ft. thick, which lies immediately below the Fifteen-foot Coal. : . The Coal Measures of this district may be conveniently divided into two groups. The upper one, amounting to 500 or 600 ft. in thickness, contains no workable coals, and probably corresponds to the Red Measures of Fifeshire, which have-been correlated with, the Middle Goal Measures of England. Its base line has been drawn in the Dalkeith district at the top of a marine bed, to be subsequently described. These upper beds occupy an area, less than a square mile in extent, on the north side of the Sheriffhall fault, and in the central and northern parts of this area they generally dip south, so that the underlying measures emerge from below them a little above the junction of the North and South Esk. It is probable that the lower part of the same barren beds recurs at the northern end of the coal basin near Musselburgh, but its outcrop here is entirely hidden beneath raised beach materials and drift. . The lower or coal-bearing group of the Coal Measures underlying these. red barren strata may. be arranged in two subdivisions: (1) an upper or Craighall set of coals, which do not. occur on the south side of the Sheriffhall fault; (2) a lower set, which in the north-western part of the basin are often called the Brunstane Coals, and on the north-eastern side the Cowpits Coals. These two groups of coals are separated by about 200 ft. of strata, in which no thick coal, or only one—the Golden Coal *—appears to occur. In the neighbourhood of Joppa and Craighall the total thickness of all the coals exceeding 23 in. in both these groups appears to be about 68 ft. It is believed, as already indicated, that the Fifteen- foot or Ell Coal of Joppa and Niddrie corresponds to the Parrot Rough of Whitehill, or perhaps to the Parrot Rough and Jewel combined. The Nine-foot may correspond to the Splint of White- hill, and Salters to the Great Seam, but the last correlation is doubtful, as the Great Seam appears to be only from 1 to 15 in. thick at Elginhaugh and Eskbank. The total thickness of the lower seams, counting downwards from the top of the Great or Salters, is greater in the northern. part of the basin than in the southern. In the New Craighall Colliery, Niddrie, in a crosscut from the Four- foot to Salters seam, the collective thickness of the Salters, Nine- foot, Fifteen-foot and Four-foot seams is estimated to be about 21 ft., and the total thickness of these together with the Seven-foot Coal is, in this locality, probably about 26 ft. In the Whitehill winding shaft the collective thickness of the Great Seam and the lower coals is about. 18 ft., and there is probably a lower coal—the Jenny Meggat—about 18 in. thick. : Many coarse false-bedded grits occur within the Coal Measures, parts of which are often of a reddish colour and have a considerable resemblance to certain members of the Roslin Sandstone series. A bed of this character lies immediately below the Jewel Coal of * Mr. Milne (op. cit.) places this coal about 40 ft. below the Jewel Seam, and gives its thickness at various places on the west side of the basin. In the new Woolmet pit it is 16 ft, below the Jewel Coal, 256 Coal Measures of Mid-Lothian Basin. Whitehill—and thus not far above the top of the Roslin Sandstone— a second, often called the “Rough Coal post,” just below the Great Seam, a third, which is well seen in the part of Dalhousie Burn below Cockpen Church, some distance above the Great Seam, and others in the still higher measures in Dalkeith Park. A few thin bands of impure limestone have. been found on different horizons, all of which are above the position of the Great Seam. Some of them are compact and slightly argillaceous, and are associated with red or purple shales, but one, which is taken as the top of the Lower Coal Measures, is partly of marine origin and con- tains remains of Spirifer. The general lithological character of the grey shales differs to some extent from that of the shales in the underlying Edge Coal group, being rather less sandy and less micaceous. The sandstones in the Coal Measures, on the other hand, are perhaps as a rule rather less mixed with shaly material than the arenaceous beds in the Edge Coal group. These features are not, however, sufficiently persistent to be of much value by themselves for purposes of differentiation. It is by means of the fossil flora and fish fauna that these two coal- bearing divisions of the Carboniferous system can be distinguished with confidence. The mollusca are less numerous and do not always afford a decisive test (see p. 221). aT. 6, W. G I, Lower Coat MEASURES. JOPPA, NEW CRAIGHALL, MUSSELBURGH AND WOOLMET FIELDS. Most of the measures extending from the base of the group up to the Greymecham Coal are exposed on the shore at Joppa (see Plate VII.), but the coal outcrops are, as a rule, concealed under sand. The position of the Fifteen-foot Seam is determined by a band of ironstone nodules, containing large specimens of Carbonicola robusta, which has been found to overlie this horizon in many portions of the coal-field (see p. 254). ~The seams all occur towards the middle of the basin, and are consequently much less inclined than those of the Edge Coal group. The following inclinations in the Ell (or Fifteen-foot) Coal occur in the New Craighall Collieries—on the 450 ft. (below Ordnance Datum) level, 25° to 32°; on the 600 ft. level, 14° to 22°; and on the 800 ft. level, 15°. On the 450 ft. level the Ell Coal has the following composition :— Ell Coal—New Craighall Collieries, Ft. In. Pelt Oo 7 CoaL .. a 2 11 Fireclay .. 2 9 CoaL ne 3 6 The following section gives the thicknesses of the coals at Joppa, as well as of the intermediate strata — Joppa and Niddrie Fields. 257 Section of the Brunstane Coals at Joppa. Ft. In, Coa. (GREYMECHAM) we a 3 ae es a 3 7 Sandstone eas 20 sh Se as a .. lo Oo Coan... ane ne as ee i . 2 0 Fireclay SALTHRS ae er es a se 4 0 Coat .. re = 6 ws Me . 2 0 Sandstone and shale .. avs a ae 35 .. 45 0 Fireclay 4 23 na si, ne a .. 18 #0 Coan. ic a de se a os ove abe od Pintiay | NINE-Foor ne oy ae se Je 2 <0 Coan... a3 oe S ai bea ss -. 5 6, Shale .. ng a ne a se ad .. 81 0 Coat, Tee og ss a we ate .. 12 6 Red sandstone . ox i os si 4 -- 100 O Fireclay eas a a a5 oe wa 8 0 Sandstone and shale i a Sa - ae . 16 6 Coat, Four-Foor .. 88 as fe ee be a A 0 ' Fireclay "3 si a a a es - 6 O Sandstone ie ve 8 a ae . 8 O Fireclay with ironstone is Be a aH -. 20 O Sandstone aes ie st Ses “ oe .. 24 0 Coat... a ne ts Be iis os sdo Gls 3B Fireclay oe eg 4 0 Coat... SEVEN-FOOT £4 =i #4 . 6 O Fireclay ce ay 9 on e eg ower oe 36 CoaL te - of ‘ie = ae a 2 O Fireclay 1 6 434 5 It may be observed that the thicknesses of the coals, etc., given in the above section are considerably greater than those calculated from the information obtained respecting the beds in a cross cut mine, driven from the Four-foot Coal to the Salters Seam in the New Craighall Colliery, Niddrie, from which the following vertical section has been constructed :— Section in the New Craighall Colliery, Niddrie. ty St onl B Fakes SaLTers CoaL Fireclay Blaes_ .. Kingle, hard .. Bastard fireclay Sandstone, hard Bastard fireclay Blaes, fireclay an Coal Nivg-root Coa .. Fireclay, holing Blaes_ .. Faky candstone Blaes, “ mussels ” and ‘balls (ironstone) FirteEn-Froot Coat - i Fireclay, holing Sandstone Fireclay Blaes a oom De ATTIRE ODOR RHE OanNaed _ ADOWDAWOKHADROCMWWOWHRDOOO rs Carry forward .. 80 17 258 Coal Measures of Mid-Lothian Basin. Ft. In. Brought forward .. 80 4 Fakes beh i an bree ie ee ge 3 A Sandstone ais ati is fe a as -. 10 7 Blaes .. he oe ais zy ee iv ae 9476 Four-Foot Coat .. oe ah iia a ay 21-410 161 7 The “mussels” referred to in this section consist of Carbonicola robusta and Carbonicola acuta, as already stated, and the following more detailed section, measured by Mr. Tait, shows more exactly the stratigraphical relations of the shale that contains them :— Detailed Section in the New Craighall Colliery, Niddrie. , Ft. _ B TOHOOWOTWWOO CoOoOoOn Ning-Foot Coan Fireclay a White sandstone Blaes or fireclay i ae ds os igh as Black shale with ironstone nodules with remains of Carbonicola robusta and Carbonicola acuta Well-bedded blaes 2 CoaL .. os IMPURE CoaL CoaL ica te ws Fireclay }Firtren-root CoaL CoaL oe IRONSTONE Coan COPROCONONMNRYWH OORT According to Dr. Hind, the specimens of Carbonicola robusta, referred to in the foregoing section, belong to a variety, previously figured by him,* found at Shotts and at Dalmellington. The section in the Woolmet shaft—a quarter of a mile east of Woolmet House—is of considerable importance since it supplies details of the strata intervening between the Brunstane or lower group and the Craighall or upper group of coals. It also shows that the Cowpits succession can now be recognised on the western side of the basin. An abstract of the section communicated by Mr. R. Martin is given below in descending order :— Ft. In. Fireclay and sandstone +3 ae “8 3 -. 27 6 Dramonp Coat, variable, but averages .. ana i . 4 0 Fireclay oe we oe 5 ae ahs in ED Coa... ns ss es ay os 35 - ve FL 0 Various strata .. ee Am a oa ia .. 26 6 JEWEL CoAL (waste) as a a ie sd is) 1B U6 Fireclay as 8 te si ae as . 16 0 GoLDEN CoaLt ... oe = soi ais a sa ID 6 Carry forward .. 88 0 * “ A Monograph on Carbonicola, Anthracomya and Naiadites,” Monograph of the Paleontographical Society, 1894-96, plate ii. figs. 3-6. The specimens figured are said by Dr. Peach to have come from two horizons, one near the Slaty-band Ironstone, at the base of the Coal Measures, and another near the Kiltongue Coal, more than 400 ft. above the base of the Coal Measures. + Probably so named from the abundant admixture with iron pyrites. See R. Bald’s ‘‘ Observations on the Coal-Field and accompanying Strata in the Vicinity of Dalkeith, Mid-Lothian,” Edin. Phil. Jour., 1827, vol. iv. p._115, Woolmet and Craighall Sections. 259 Brought forward Fireclay Ss bd “et CoaL .. Fireclay Sandstone. . Coan Various strata CoaL .. Fireclay Coan .. Various strata Coan .. Various strata Sandstone. . , Cowrits Livre SPLINT CoaL Various strata Coal .. a Fireclay Sandstone. . Coat .. Fireclay Coat .. Pelt . Fireclay and blaes Cowrits Five-root Coat Fireclay Grey sandstone Blaes QuaRRY CoaL . Strata Gass or GREYMECHAM Coat, Strata 3 Barrs or SALTERS Coan Strata a NINE-Foot SEAM co bo ew aD oe ~ o SPOSOSCONOQONAMHWOOWROROARAWOROROOCCOROOH CORNOE WO —_ a Lal BRD Pp eS Oot rN ow 662 The thicknesses of the upper group of coals, etc., at Craighall are given in the subjoined table :— Ft. In. CLAYKNOWES CoaL 340 Sandstone and shale 28 0 Coat .. ni ish 36 is in ob 6 Sandstone ‘and shale ie a ais i .. 185 O Sandstone (red and eile a Se af .. 185 0 Shale tee s ie a Sa sev AE. 80 Coat (the Sprint) .. i os Bi ws -. 5 O Sandstone and shale... ae ae ie :. 45 0 TRONSTONE se oh a aa ies -. O Of Sandstone. . = a i sie ee .. 18 +O Coat (the RovaH) .. 24 lis i st . 4 0 Shale sce ei a a re -. 42 90 Sandstone and shale... a ss vis .. 18 0 Coa (the Bezriz) .. es ea of ae . 6 O Sandstone. . na ae Xe i es .. 386 9 Grey bands ae sh si ss eg -» 16 0 Shale (red) ass 95 ay .. 80 0 Sandstone (red and 1 white) i ais ae -- 22 0 Shale as itis A a .. 28 O Coat (the DIAMOND) 8 es a ag - 6 O Sandstone and shale... as ee ey .. 20 O Coan (the JewEL) .. «a